394 research outputs found
Multidrug-resistant Bacteroides fragilis group on the rise in Europe?
We report a case of multidrug-resistance (MDR) in a strain of Bacteroides fragilis from a blood culture and abdominal fluid in a Danish patient. The patient had not been travelling for several years and had not received antibiotics prior to the present case. We also summarize the cases that have been reported to date of MDR B. fragilis group in Europe. As far as we know, a case like this with MDR B. fragilis has not been described in Scandinavia before. Š 2012
Bootstrapping Conditional GANs for Video Game Level Generation
Generative Adversarial Networks (GANs) have shown im-pressive results for
image generation. However, GANs facechallenges in generating contents with
certain types of con-straints, such as game levels. Specifically, it is
difficult togenerate levels that have aesthetic appeal and are playable atthe
same time. Additionally, because training data usually islimited, it is
challenging to generate unique levels with cur-rent GANs. In this paper, we
propose a new GAN architec-ture namedConditional Embedding Self-Attention
Genera-tive Adversarial Network(CESAGAN) and a new bootstrap-ping training
procedure. The CESAGAN is a modification ofthe self-attention GAN that
incorporates an embedding fea-ture vector input to condition the training of
the discriminatorand generator. This allows the network to model
non-localdependency between game objects, and to count objects. Ad-ditionally,
to reduce the number of levels necessary to trainthe GAN, we propose a
bootstrapping mechanism in whichplayable generated levels are added to the
training set. Theresults demonstrate that the new approach does not only
gen-erate a larger number of levels that are playable but also gen-erates fewer
duplicate levels compared to a standard GAN
Investigation of factors influencing the immunogenicity of hCG as a potential cancer vaccine
Human hCG and its βâsubunit (hCGβ) are tumour autocrine growth factors whose presence in the serum of cancer patients has been linked to poorer prognosis. Previous studies have shown that vaccines, which target these molecules and/or the 37 amino acid Câterminal hCGβ peptide (hCGβCTP), induce antibody responses in a majority of human recipients. Here we explored whether the immunogenicity of vaccines containing an hCGβ mutant (hCGβR68E, designed to eliminate crossâreactivity with luteinizing hormone) or hCGβCTP could be enhanced by coupling the immunogen to different carriers (KLH or Hsp70) using different crossâlinkers (EDC or GAD) and formulated with different adjuvants (RIBI or Montanide ISA720).
While there was little to choose between KLH and Hsp70 as carriers, their influence on the effectiveness of a vaccine containing the BAChCGβR68E mutant was less marked, presumably because being a foreign species, this mutant protein itself might provide Tâhelper epitopes. The mutant provided a significantly better vaccine than the hCGβCTP peptide irrespective of the carrier used, how it was crossâlinked to the carrier or which adjuvant was used when hCG was the target. Nonetheless, for use in humans where hCG is a tolerated selfâprotein, the need for a carrier is of fundamental importance. Highest antibody titres were obtained by linking the BAChCGβR68E to Hsp70 as a carrier by GAD and using RIBI as the adjuvant, which also resulted in antibodies with significantly higher affinity than those elicited by hCGβCTP peptide vaccine. This makes this mutant vaccine a promising candidate for therapeutic studies in hCGβâpositive cancer patients
Constraints on the Obliquities of Kepler Planet-Hosting Stars
Stars with hot Jupiters have obliquities ranging from 0-180 degrees, but
relatively little is known about the obliquities of stars with smaller planets.
Using data from the California-Kepler Survey, we investigate the obliquities of
stars with planets spanning a wide range of sizes, most of which are smaller
than Neptune. First, we identify 156 planet hosts for which measurements of the
projected rotation velocity (vsini) and rotation period are both available. By
combining estimates of v and vsini, we find nearly all the stars to be
compatible with high inclination, and hence, low obliquity (less than about 20
degrees). Second, we focus on a sample of 159 hot stars (> 6000K) for which
vsini is available but not necessarily the rotation period. We find 6 stars for
which vsini is anomalously low, an indicator of high obliquity. Half of these
have hot Jupiters, even though only 3% of the stars that were searched have hot
Jupiters. We also compare the vsini distribution of the hot stars with planets
to that of 83 control stars selected without prior knowledge of planets. The
mean vsini of the control stars is lower than that of the planet hosts by a
factor of approximately pi/4, as one would expect if the planet hosts have low
obliquities. All these findings suggest that the Kepler planet-hosting stars
generally have low obliquities, with the exception of hot stars with hot
Jupiters.Comment: AJ, in pres
Quantum fingerprinting
Classical fingerprinting associates with each string a shorter string (its
fingerprint), such that, with high probability, any two distinct strings can be
distinguished by comparing their fingerprints alone. The fingerprints can be
exponentially smaller than the original strings if the parties preparing the
fingerprints share a random key, but not if they only have access to
uncorrelated random sources. In this paper we show that fingerprints consisting
of quantum information can be made exponentially smaller than the original
strings without any correlations or entanglement between the parties: we give a
scheme where the quantum fingerprints are exponentially shorter than the
original strings and we give a test that distinguishes any two unknown quantum
fingerprints with high probability. Our scheme implies an exponential
quantum/classical gap for the equality problem in the simultaneous message
passing model of communication complexity. We optimize several aspects of our
scheme.Comment: 8 pages, LaTeX, one figur
EPIC 219217635: A Doubly Eclipsing Quadruple System Containing an Evolved Binary
We have discovered a doubly eclipsing, bound, quadruple star system in the
field of K2 Campaign 7. EPIC 219217635 is a stellar image with that
contains an eclipsing binary (`EB') with d and a second EB with
d. We have obtained followup radial-velocity (`RV')
spectroscopy observations, adaptive optics imaging, as well as ground-based
photometric observations. From our analysis of all the observations, we derive
good estimates for a number of the system parameters. We conclude that (1) both
binaries are bound in a quadruple star system; (2) a linear trend to the RV
curve of binary A is found over a 2-year interval, corresponding to an
acceleration, cm s; (3) small
irregular variations are seen in the eclipse-timing variations (`ETVs')
detected over the same interval; (4) the orbital separation of the quadruple
system is probably in the range of 8-25 AU; and (5) the orbital planes of the
two binaries must be inclined with respect to each other by at least
25. In addition, we find that binary B is evolved, and the cooler and
currently less massive star has transferred much of its envelope to the
currently more massive star. We have also demonstrated that the system is
sufficiently bright that the eclipses can be followed using small ground-based
telescopes, and that this system may be profitably studied over the next decade
when the outer orbit of the quadruple is expected to manifest itself in the ETV
and/or RV curves.Comment: Accepted for publication in MNRA
Warm-Start AlphaZero Self-Play Search Enhancements
Recently, AlphaZero has achieved landmark results in deep reinforcement
learning, by providing a single self-play architecture that learned three
different games at super human level. AlphaZero is a large and complicated
system with many parameters, and success requires much compute power and
fine-tuning. Reproducing results in other games is a challenge, and many
researchers are looking for ways to improve results while reducing
computational demands. AlphaZero's design is purely based on self-play and
makes no use of labeled expert data ordomain specific enhancements; it is
designed to learn from scratch. We propose a novel approach to deal with this
cold-start problem by employing simple search enhancements at the beginning
phase of self-play training, namely Rollout, Rapid Action Value Estimate (RAVE)
and dynamically weighted combinations of these with the neural network, and
Rolling Horizon Evolutionary Algorithms (RHEA). Our experiments indicate that
most of these enhancements improve the performance of their baseline player in
three different (small) board games, with especially RAVE based variants
playing strongly
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