2,404 research outputs found

    Mechanism design for aggregating energy consumption and quality of service in speed scaling scheduling

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    We consider a strategic game, where players submit jobs to a machine that executes all jobs in a way that minimizes energy while respecting the given deadlines. The energy consumption is then charged to the players in some way. Each player wants to minimize the sum of that charge and of their job's deadline multiplied by a priority weight. Two charging schemes are studied, the proportional cost share which does not always admit pure Nash equilibria, and the marginal cost share, which does always admit pure Nash equilibria, at the price of overcharging by a constant factor

    Investigating Fatigue Performance on the Foamed Asphalt Specimens Generated Using Different Foam Properties

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    An evaluation of fatigue resistance for foamed asphalt mixture is very demanding since the binder is not continuously distributed on the aggregate surface and this mixtures contains water, the content of which dramatically affects the mechanical properties. This paper discusses the results of laboratory fatigue testingon the foamed asphalt mixtures in which the specimens are generated using three different foamed bitumen properties. Foamed bitumen as the binder was produced at three different foaming water content (FWC) at a temperature of 180oC using a 70/100 pen. The aggregates were mechanically mixed with foamed bitumen using a Hobart mixer. The resulting mixtures were then compacted using a gyratory compactor to generatespecimen with diameter of 100 mm. The specimens were fatigue tested at various stress levels at a temperature of 20oC following a curing period of 3 days at 40oC. Overall, fatigue performance of foamed asphalt can be identified based upon both stress and strain for mixtures produced at FWC 1%, 5%, and 10%

    The relationship of telomere length to baseline corticosterone levels in nestlings of an altricial passerine bird in natural populations.

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    BackgroundEnvironmental stressors increase the secretion of glucocorticoids that in turn can shorten telomeres via oxidative damage. Modification of telomere length, as a result of adversity faced early in life, can modify an individual's phenotype. Studies in captivity have suggested a relationship between glucocorticoids and telomere length in developing individuals, however less is known about that relationship in natural populations.MethodsIn order to evaluate the effect of early environmental stressors on telomere length in natural populations, we compared baseline corticosterone (CORT) levels and telomere length in nestlings of the same age. We collected blood samples for hormone assay and telomere determination from two geographically distinct populations of the Thorn-tailed Rayadito (Aphrastura spinicauda) that differed in brood size; nestlings body mass and primary productivity. Within each population we used path analysis to evaluate the relationship between brood size, body mass, baseline CORT and telomere length.ResultsWithin each distinct population, path coefficients showed a positive relationship between brood size and baseline CORT and a strong and negative correlation between baseline CORT and telomere length. In general, nestlings that presented higher baseline CORT levels tended to present shorter telomeres. When comparing populations it was the low latitude population that presented higher levels of baseline CORT and shorter telomere length.ConclusionsTaken together our results reveal the importance of the condition experienced early in life in affecting telomere length, and the relevance of integrative studies carried out in natural conditions

    Endohedral terthiophene in zigzag carbon nanotubes: Density functional calculations

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    The inclusion and encapsulation of terthiophene (T3) molecules inside zigzag single-walled carbon nanotubes (CNTs) is addressed by density functional calculations. We consider the T3 molecule inside five semiconducting CNTs with diameters ranging from 9.6 to 12.7 Ang. Our results show that the T3 inclusion process is exothermic for CNTs with diameters larger than 9.5 Ang. The highest energy gain is found to be of 2 eV, decreasing as the CNT diameter increases. This notable effect of stabilization is attributed to the positively charged CNT inner space, as induced by its curvature, which is able to accommodate the neutral T3 molecule. The band structure of the T3@CNT system shows that T3 preserves its electronic identity inside the CNTs, superimposing their molecular orbitals onto the empty CNT band structure without hybridization. Our results predict that the electronic states added by the T3 molecules would give rise to optical effects and nonradiative relaxation from excited states.Comment: 5 pages, 5 figures, 1 table, accepted in PR

    Aproximación a la probabilidad en el aula de educación primaria. Un estudio de caso sobre los primeros elementos lingüísticos

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    El lenguaje desempeña un rol fundamental en el proceso de enseñanza-aprendizaje de la matemática, especialmente de la probabilidad, debido a la estrecha relación existente entre las expresiones de uso común y el lenguaje de corte matemático o probabilístico. En este trabajo se presenta un análisis de los primeros elementos lingüísticos vinculados al lenguaje probabilístico presentes en dos sesiones de clase de un segundo curso de Educación Primaria de una escuela chilena. Para ello, nos hemos centrado en cuatro grandes focos que promueven el lenguaje probabilístico y el desarrollo de la alfabetización probabilística: lenguaje verbal, lenguaje numérico, lenguaje tabular y lenguaje gráfico. Los resultados muestran un fuerte predominio de términos y expresiones verbales provenientes del lenguaje común vinculadas principalmente al significado intuitivo de la probabilidad, que transitan hacia conceptos de corte probabilístico

    Correlation between magnetic interactions and domain structure in A1 FePt ferromagnetic thin films

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    We have investigated the relationship between the domain structure and the magnetic interactions in a series of FePt ferromagnetic thin films of varying thickness. As-made films grow in the magnetically soft and chemically disordered A1 phase that may have two distinct domain structures. Above a critical thickness dcr30d_{cr}\sim 30 nm the presence of an out of plane anisotropy induces the formation of stripes, while for d<dcrd<d_{cr} planar domains occur. Magnetic interactions have been characterized using the well known DCD-IRM remanence protocols, δM\delta M plots, and magnetic viscosity measurements. We have observed a strong correlation between the domain configuration and the sign of the magnetic interactions. Planar domains are associated with positive exchange-like interactions, while stripe domains have a strong negative dipolar-like contribution. In this last case we have found a close correlation between the interaction parameter and the surface dipolar energy of the stripe domain structure. Using time dependent magnetic viscosity measurements, we have also estimated an average activation volume for magnetic reversal, Vac1.37×104\langle V_{ac}\rangle \sim 1.37\times 10^{4} nm3,^{3}, which is approximately independent of the film thickness or the stripe period.Comment: 25 pages, 11 figure
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