2,766 research outputs found
Additive Asymmetric Quantum Codes
We present a general construction of asymmetric quantum codes based on
additive codes under the trace Hermitian inner product. Various families of
additive codes over \F_{4} are used in the construction of many asymmetric
quantum codes over \F_{4}.Comment: Accepted for publication March 2, 2011, IEEE Transactions on
Information Theory, to appea
Gaussian Process Planning with Lipschitz Continuous Reward Functions: Towards Unifying Bayesian Optimization, Active Learning, and Beyond
This paper presents a novel nonmyopic adaptive Gaussian process planning
(GPP) framework endowed with a general class of Lipschitz continuous reward
functions that can unify some active learning/sensing and Bayesian optimization
criteria and offer practitioners some flexibility to specify their desired
choices for defining new tasks/problems. In particular, it utilizes a
principled Bayesian sequential decision problem framework for jointly and
naturally optimizing the exploration-exploitation trade-off. In general, the
resulting induced GPP policy cannot be derived exactly due to an uncountable
set of candidate observations. A key contribution of our work here thus lies in
exploiting the Lipschitz continuity of the reward functions to solve for a
nonmyopic adaptive epsilon-optimal GPP (epsilon-GPP) policy. To plan in real
time, we further propose an asymptotically optimal, branch-and-bound anytime
variant of epsilon-GPP with performance guarantee. We empirically demonstrate
the effectiveness of our epsilon-GPP policy and its anytime variant in Bayesian
optimization and an energy harvesting task.Comment: 30th AAAI Conference on Artificial Intelligence (AAAI 2016), Extended
version with proofs, 17 page
Molecular regulation of seed and fruit set
Seed and fruit set are established during and soon after fertilization and determine seed and fruit number, their final size and, hence, yield potential. These processes are highly sensitive to biotic and abiotic stresses, which often lead to seed and fruit abortion. Here, we review the regulation of assimilate partitioning, including the potential roles of recently identified sucrose efflux transporters in seed and fruit set and examine the similarities of sucrose import and hydrolysis for both pollen and ovary sinks, and similar causes of abortion. We also discuss the molecular origins of parthenocarpy and the central roles of auxins and gibberellins in fruit set. The recently completed strawberry (Fragaria vesca) and tomato (Solanum lycopersicum) genomes have added to the existing crop databases, and new models are starting to be used in fruit and seed set studies
Topographical changes in photo-responsive liquid crystal films:a computational analysis
Switchable materials in response to external stimuli serve as building blocks to construct microscale functionalized actuators and sensors. Azobenzene-modified liquid crystal (LC) polymeric networks, that combine liquid crystalline orientational order and elasticity, reversibly undergo conformational changes powered by light. We present a computational framework to describe photo-induced topographical transformations of azobenzene-modified LC glassy polymer coatings. A nonlinear light penetration model is combined with an opto-mechanical constitutive relation to simulate various ordered and corrugated topographical textures resulting from aligned or randomly distributed LC molecule orientations. Our results shed light on the fundamental physical mechanisms of light-triggered surface undulations and can be used as guidelines to optimize surface modulation and roughness in emerging fields that involve haptics interfacing, friction control and wetting manipulation.</p
KAYAK-alpha modulates circadian transcriptional feedback loops in Drosophila pacemaker neurons
Circadian rhythms are generated by well-conserved interlocked transcriptional feedback loops in animals. In Drosophila, the dimeric transcription factor CLOCK/CYCLE (CLK/CYC) promotes period (per), timeless (tim), vrille (vri), and PAR-domain protein 1 (Pdp1) transcription. PER and TIM negatively feed back on CLK/CYC transcriptional activity, whereas VRI and PDP1 negatively and positively regulate Clk transcription, respectively. Here, we show that the alpha isoform of the Drosophila FOS homolog KAYAK (KAY) is required for normal circadian behavior. KAY-alpha downregulation in circadian pacemaker neurons increases period length by 1.5 h. This behavioral phenotype is correlated with decreased expression of several circadian proteins. The strongest effects are on CLK and the neuropeptide PIGMENT DISPERSING FACTOR, which are both under VRI and PDP1 control. Consistently, KAY-alpha can bind to VRI and inhibit its interaction with the Clk promoter. Interestingly, KAY-alpha can also repress CLK activity. Hence, in flies with low KAY-alpha levels, CLK derepression would partially compensate for increased VRI repression, thus attenuating the consequences of KAY-alpha downregulation on CLK targets. We propose that the double role of KAY-alpha in the two transcriptional loops controlling Drosophila circadian behavior brings precision and stability to their oscillations
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