24,906 research outputs found
Distribution of Complex and Core Lipids within New Hyperthermophilic Members of the Archaea Domain
Core and complex lipids of several new hyperthermophilic archaeal isolates were analyzed. The organisms belong to the Sulfolobales,Archaeoglobus, Pyrobaculum, and Methanococcus. A detailed structural investigation of complex lipids of Pyrobaculum species is reported. The different lipid structures are of help for
a rapid and simple phylogenetic classification of the new isolates. They are in agreement with the classification based on other features
Experimentally Feasible Security Check for n-qubit Quantum Secret Sharing
In this article we present a general security strategy for quantum secret
sharing (QSS) protocols based on the HBB scheme presented by Hillery, Bu\v{z}ek
and Berthiaume [Phys. Rev A \textbf{59}, 1829 (1999)]. We focus on a
generalization of the HBB protocol to communication parties thus including
-partite GHZ states. We show that the multipartite version of the HBB scheme
is insecure in certain settings and impractical when going to large . To
provide security for such QSS schemes in general we use the framework presented
by some of the authors [M. Huber, F. Minert, A. Gabriel, B. C. Hiesmayr, Phys.
Rev. Lett. \textbf{104}, 210501 (2010)] to detect certain genuine partite
entanglement between the communication parties. In particular, we present a
simple inequality which tests the security.Comment: 5 pages, submitted to Phys. Rev.
HIV/AIDS, Security and Conflict: New Realities, New Responses
Ten years after the HIV/AIDS epidemic itself was identified as a threat to international peace and security, findings from the three-year AIDS, Security and Conflict Initiative (ASCI)(1) present evidence of the mutually reinforcing dynamics linking HIV/AIDS, conflict and security
Transition from van-der-Waals to H Bonds dominated Interaction in n-Propanol physisorbed on Graphite
Multilayer sorption isotherms of 1-propanol on graphite have been measured by
means of high-resolution ellipsometry within the liquid regime of the adsorbed
film for temperatures ranging from 180 to 260 K. In the first three monolayers
the molecules are oriented parallel to the substrate and the growth is roughly
consistent with the Frenkel-Halsey-Hill-model (FHH) that is obeyed in
van-der-Waals systems on strong substrates. The condensation of the fourth and
higher layers is delayed with respect to the FHH-model. The fourth layer is
actually a bilayer. Furthermore there is indication of a wetting transition.
The results are interpreted in terms of hydrogen-bridge bonding within and
between the layers.Comment: 4 pages, 3 figure
Flicker as a tool for characterizing planets through Asterodensity Profiling
Variability in the time series brightness of a star on a timescale of 8
hours, known as 'flicker', has been previously demonstrated to serve as a proxy
for the surface gravity of a star by Bastien et al. (2013). Although surface
gravity is crucial for stellar classification, it is the mean stellar density
which is most useful when studying transiting exoplanets, due to its direct
impact on the transit light curve shape. Indeed, an accurate and independent
measure of the stellar density can be leveraged to infer subtle properties of a
transiting system, such as the companion's orbital eccentricity via
asterodensity profiling. We here calibrate flicker to the mean stellar density
of 439 Kepler targets with asteroseismology, allowing us to derive a new
empirical relation given by
. The calibration is valid for stars with
KK, and flicker estimates corresponding
to stars with . Our relation has a model error in the
stellar density of 31.7% and so has times lower precision than that
from asteroseismology but is applicable to a sample times greater.
Flicker therefore provides an empirical method to enable asterodensity
profiling on hundreds of planetary candidates from present and future missions.Comment: 6 pages, 3 figures, 1 table. Accepted to ApJ Letters. Code available
at https://www.cfa.harvard.edu/~dkipping/flicker.htm
Probing Sterile Neutrino Parameters with Double Chooz, Daya Bay and RENO
In this work, we present a realistic analysis of the potential of the
present-day reactor experiments Double Chooz, Daya Bay and RENO for probing the
existence of sterile neutrinos. We present exclusion regions for sterile
oscillation parameters for each of these experiments, using simulations with
realistic estimates of systematic errors and detector resolutions, and compare
the sterile parameter sensitivity regions we obtain with the existing bounds
from other reactor experiments. We find that these experimental set-ups give
significant bounds on the parameter \Theta_{ee} especially in the low sterile
oscillation region 0.01 < \Delta m_{41}^2 < 0.05 eV^2. These bounds can add to
our understanding of the sterile neutrino sector since there is still a tension
in the allowed regions from different experiments for sterile parameters.Comment: 12 pages, 5 figure
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