31,800 research outputs found
Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort
Cocoa flavanols (CF) positively influence physiological processes in ways that suggest their consumption may improve aspects of cognitive function. This study investigated the acute cognitive and subjective effects of CF consumption during sustained mental demand. In this randomized, controlled, double-blinded, balanced, three period crossover trial 30 healthy adults consumed drinks containing 520 mg, 994 mg CF and a matched control, with a three-day washout between drinks. Assessments included the state anxiety inventory and repeated 10-min cycles of a Cognitive Demand Battery comprising of two serial subtraction tasks (Serial Threes and Serial Sevens), a Rapid Visual Information Processing (RVIP) task and a mental fatigue scale, over the course of 1 h. Consumption of both 520 mg and 994 mg CF significantly improved Serial Threes performance. The 994 mg CF beverage significantly speeded RVIP responses but also resulted in more errors during Serial Sevens. Increases in self-reported mental fatigue were significantly attenuated by the consumption of the 520 mg CF beverage only. This is the first report of acute cognitive improvements following CF consumption in healthy adults. While the mechanisms underlying the effects are unknown they may be related to known effects of CF on endothelial function and blood flow
A quantum genetic algorithm with quantum crossover and mutation operations
In the context of evolutionary quantum computing in the literal meaning, a
quantum crossover operation has not been introduced so far. Here, we introduce
a novel quantum genetic algorithm which has a quantum crossover procedure
performing crossovers among all chromosomes in parallel for each generation. A
complexity analysis shows that a quadratic speedup is achieved over its
classical counterpart in the dominant factor of the run time to handle each
generation.Comment: 21 pages, 1 table, v2: typos corrected, minor modifications in
sections 3.5 and 4, v3: minor revision, title changed (original title:
Semiclassical genetic algorithm with quantum crossover and mutation
operations), v4: minor revision, v5: minor grammatical corrections, to appear
in QI
High-speed detection of emergent market clustering via an unsupervised parallel genetic algorithm
We implement a master-slave parallel genetic algorithm (PGA) with a bespoke
log-likelihood fitness function to identify emergent clusters within price
evolutions. We use graphics processing units (GPUs) to implement a PGA and
visualise the results using disjoint minimal spanning trees (MSTs). We
demonstrate that our GPU PGA, implemented on a commercially available general
purpose GPU, is able to recover stock clusters in sub-second speed, based on a
subset of stocks in the South African market. This represents a pragmatic
choice for low-cost, scalable parallel computing and is significantly faster
than a prototype serial implementation in an optimised C-based
fourth-generation programming language, although the results are not directly
comparable due to compiler differences. Combined with fast online intraday
correlation matrix estimation from high frequency data for cluster
identification, the proposed implementation offers cost-effective,
near-real-time risk assessment for financial practitioners.Comment: 10 pages, 5 figures, 4 tables, More thorough discussion of
implementatio
Soy protein improves cardiovascular risk in subclinical hypothyroidism : a randomized double-blinded crossover study
© 2017 Endocrine Society. Background: Soy protein with isoflavones appears to have an adverse effect on thyroid function, but it is not known whether it is the protein or isoflavone component that is deleterious. The effect of isoflavone-free soy on thyroid function was determined in patients with subclinical hypothyroidism, with a secondary aim of assessing its effect on cardiovascular risk indices. Methods: This was a randomized, double-blind, crossover study involving 80 patients with subclinical (compensated) hypothyroidism. Patients were randomly assigned to either isolated soy (isoflavone-free) protein (SP) or casein protein (CP) supplementation for 8 weeks, washed out for 8 weeks, and then crossed over for a further 8-week period. Results: Thyroid function was unaffected by either a SP or CP. There were significant decreases in fasting glucose (4.760.6 vs 5.561.4, P < 0.01), insulin resistance (3.3±3.0 vs 3.8±3.4, P = 0.05), total cholesterol (4.4 ± 0.9 vs 5.3 ± 1.2, P < 0.01), triglycerides (0.9 ± 0.5 vs 1.7 ± 0.9, P < 0.1), and highly sensitive C-reactive protein (hsCRP; 0.8 ± 0.7 vs 2.6 ± 2.8, P < 0.01) in the SP group compared with the CP group. Blood pressure, low-density lipoprotein, and high-density lipoprotein remained unchanged in both groups. Conclusion: SP alone had no effect on thyroid function in patients with subclinical hypothyroidism and resulted in a significant reduction in fasting glucose, insulin resistance, total cholesterol, triglycerides, and hsCRP compared with CP
Pharmacokinetics and pharmacodynamics of tiotropium solution and tiotropium powder in chronic obstructive pulmonary disease
The aim of the study was to characterize pharmacokinetics of tiotropium solution 5 µg compared to powder 18 µg and assess dose-dependency of tiotropium solution pharmacodynamics in comparison to placebo. In total 154 patients with chronic obstructive pulmonary disease (COPD) were included in this multicenter, randomized, double-blind within-solution (1.25, 2.5, 5 µg, and placebo), and open-label powder 18 µg, crossover study, including 4-week treatment periods. Primary end points were peak plasma concentration (Cmax,ss ), and area under the plasma concentration-time profile (AUC0-6h,ss ), both at steady state. The pharmacodynamic response was assessed by serial spirometry (forced expiratory volume in 1 second/forced vital capacity). Safety was evaluated as adverse events and by electrocardiogram/Holter. Tiotropium was rapidly absorbed with a median tmax,ss of 5-7 minutes postdosing for both devices. The gMean ratio of solution 5 µg over powder 18 µg was 81% (90% confidence interval, 73-89%) for Cmax,ss and 76% (70-82%) for AUC0-6h,ss , indicating that bioequivalence was not established. Dose ordering for bronchodilation was observed. Powder 18 µg and solution 5 µg were most effective, providing comparable bronchodilation. All treatments were well tolerated with no apparent relation to dose or device. Comparable bronchodilator efficacy to powder18 µg at lower systemic exposure supports tiotropium solution 5 µg for maintenance treatment of COPD
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Class decomposition for GA-based classifier agents – A Pitt approach
Incremental learning has been widely addressed in the machine learning literature to cope with learning tasks where the learning environment is ever changing or training samples become available over time. However, most research work explores incremental learning with statistical algorithms or neural networks, rather than evolutionary algorithms. The work in this paper employs genetic algorithms (GAs) as basic learning algorithms for incremental learning within one or more classifier agents in a multi-agent environment. Four new approaches with different initialization schemes are proposed. They keep the old solutions and use an “integration” operation to integrate them with new elements to accommodate new attributes, while biased mutation and crossover operations are adopted to further evolve a reinforced solution. The simulation results on benchmark classification data sets show that the proposed approaches can deal with the arrival of new input attributes and integrate them with the original input space. It is also shown that the proposed approaches can be successfully used for incremental learning and improve classification rates as compared to the retraining GA. Possible applications for continuous incremental training and feature selection are also discussed
Correlated electron transport through double quantum dots coupled to normal and superconducting leads
We study Andreev transport through double quantum dots connected in series
normal and superconducting (SC) leads, using the numerical renormalization
group. The ground state of this system shows a crossover between a local
Cooper-pairing singlet state and a Kondo singlet state, which is caused by the
competition between the Coulomb interaction and the SC proximity. We show that
the ground-state properties reflect this crossover especially for small values
of the inter-dot coupling , while in the opposite case, for large ,
another singlet with an inter-dot character becomes dominant. We find that the
conductance for the local SC singlet state has a peak with the unitary-limit
value . In contrast, the Andreev reflection is suppressed in the Kondo
regime by the Coulomb interaction. Furthermore, the conductance has two
successive peaks in the transient region of the crossover. It is further
elucidated that the gate voltage gives a different variation into the
crossover. Specifically, as the energy level of the dot that is coupled to the
normal lead varies, the Kondo screening cloud is deformed to a long-range
singlet bond.Comment: 11 pages, 10 figure
On the genetic optimization of APSK constellations for satellite broadcasting
Both satellite transmissions and DVB applications over satellite present
peculiar characteristics that could be taken into consideration in order to
further exploit the optimality of the transmission. In this paper, starting
from the state-of-the-art, the optimization of the APSK constellation through
asymmetric symbols arrangement is investigated for its use in satellite
communications. In particular, the optimization problem is tackled by means of
Genetic Algorithms that have already been demonstrated to work nicely with
complex non-linear optimization problems like the one presented hereinafter.
This work aims at studying the various parameters involved in the optimization
routine in order to establish those that best fit this case, thus further
enhancing the constellation.Comment: IEEE International Symposium on Broadband Multimedia Systems and
Broadcasting (BMSB), 2014; IEEE proceedings, 201
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