26,957 research outputs found
Prediction Possibility in the Fractal Overlap Model of Earthquakes
The two-fractal overlap model of earthquake shows that the contact area
distribution of two fractal surfaces follows power law decay in many cases and
this agrees with the Guttenberg-Richter power law. Here, we attempt to predict
the large events (earthquakes) in this model through the overlap time-series
analysis. Taking only the Cantor sets, the overlap sizes (contact areas) are
noted when one Cantor set moves over the other with uniform velocity. This
gives a time series containing different overlap sizes. Our numerical study
here shows that the cumulative overlap size grows almost linearly with time and
when the overlapsizes are added up to a pre-assigned large event (earthquake)
and then reset to `zero' level, the corresponding cumulative overlap sizes
grows upto some discrete (quantised) levels. This observation should help to
predict the possibility of `large events' in this (overlap) time series.Comment: 6 pages, 6 figures. To be published as proc. NATO conf. CMDS-10,
Soresh, Israel, July 2003. Eds. D. J. Bergman & E. Inan, KLUWER PUB
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Design of domestic photovoltaics manufacturing systems under global constraints and uncertainty
As global political discourse is taking place where the need for a cleaner energy mix is constantly highlighted, manufacturing strategies are becoming more relevant. Thus, the photovoltaics system design is a crucial aspect related with the overall sustainability. In fact, various countries are considering the potential to locally manufacture different elements of the photovoltaics (PV) value chain and the strategies to incentivize a local manufacturing base. This paper develops a mathematical programming approach for the optimal design of a PV manufacturing value chain considering diverse criteria linked to economic and environmental performance such as minimum sustainable price, transportation capacity, among others, and considering uncertainty. In addition, the proposed methodology involves the dependence over time of supply chain variables and economic parameters such as inflation, electricity cost, and weighted average cost of capital, to determine the manufacturing system topology under uncertain conditions. Our results highlight the importance of planning models to develop markets policies related to supply chains, production level changes and imposed tariffs all while involving uncertainty in economic parameters, which is an improvement compared to planning models that use deterministic formulations. Finally, the proposed methodology and results can encourage decision-making considering probable variations in different parameters
Patterns in high-frequency FX data: Discovery of 12 empirical scaling laws
We have discovered 12 independent new empirical scaling laws in foreign
exchange data-series that hold for close to three orders of magnitude and
across 13 currency exchange rates. Our statistical analysis crucially depends
on an event-based approach that measures the relationship between different
types of events. The scaling laws give an accurate estimation of the length of
the price-curve coastline, which turns out to be surprisingly long. The new
laws substantially extend the catalogue of stylised facts and sharply constrain
the space of possible theoretical explanations of the market mechanisms.Comment: 26 pages, 3 figures, 23 tables,2nd version (text made more concise
and readable, algorithm pseudocode, results unchanged), 5-year datasets
(USD-JPY, EUR-USD) provided at http://www.olsen.ch/more/datasets
Monte carlo within simulated annealing for integral constrained optimizations
For years, Value-at-Risk and Expected Shortfall have been well established measures of market risk and the Basel Committee on Banking Supervision recommends their use when controlling risk. But their computations might be intractable if we do not rely on simplifying assumptions, in particular on distributions of returns. One of the difficulties is linked to the need for Integral Constrained Optimizations. In this article, two new stochastic optimization-based Simulated Annealing algorithms are proposed for addressing problems associated with the use of statistical methods that rely on extremizing a non-necessarily differentiable criterion function, therefore facing the problem of the computation of a non-analytically reducible integral constraint. We first provide an illustrative example when maximizing an integral constrained likelihood for the stress-strength reliability that confirms the effectiveness of the algorithms. Our results indicate no clear difference in convergence, but we favor the use of the problem approximation strategy styled algorithm as it is less expensive in terms of computing time. Second, we run a classical financial problem such as portfolio optimization, showing the potential of our proposed methods in financial applications
Cisgenic inhibition of the potato cold induced phosphorylase L gene expression and decrease in sugar contents
To decrease the accumulation of reducing and non-reducing sugar in potato tubers stored at low temperature, a single gene silencing vector pARTPhL-IR, harboring a part of starch phosphorylase L gene as inverted repeats with pdk intron within was constructed and transformed into potato (Solanum tuberosum L.) cultivars Agria and Marfona. Polymerase chain reaction (PCR) of nptII gene and pdk intron indicated that the RNA interference construct was transformed successfully into the genome. Real time RT-PCR analysis of starch phosphorylase L gene in stored microtubers for 90 days at 4°C showed that the expression level of this gene in transgenics ranged from 1.63 to 7.54% of that in the non-transgenic plants. Analysis of sugar content in these plants showed that the total sugar content in transgenic microtubers was significantly reduced compared to the control, up to 35% in line M4. The accumulation of reducing sugars in transgenic lines at 4°C was reduced from 9.13 (in Agria) to 5.57 mg/g fresh weight (transgenic line A5) and from 9.56 (in Marfona) to 6.52 mg/g fresh weight (transgenic line M4), implying that silencing of starch phosphorylase L gene reduced starch breakdown during cold storage conditions.Key words: Cold sweetening, potato (Solanum tuberosum L.), RNA interference, starch phosphorylase L. gene
Effect of Cs+ ions on the electrochemical nanogravimetric response of platinum electrode in acid media
Why Use the Radial Artery? The Saphenous Vein is the Second Graft of Choice for CABG in Brazil
The saphenous vein (SV) is the most commonly used conduit for coronary artery bypass surgery (CABG) and the second conduit of choice in Brazil and many other countries. The radial artery (RA) is suggested, by some, to be superior to SV grafts, although its use in the USA declined over a 10 year period. The patency of SV grafts (SVG) is improved when the vein is harvested with minimal trauma using the no-touch (NT) technique. This improved performance is due to the preservation of the outer pedicle surrounding the SV and reduction in vascular damage that occurs when using conventional techniques (CT) of harvesting. While the patency of NT SVGs has been shown superior to the RA at 36 months in one study, data from the RADIAL trial suggests the RA to be the superior conduit. When additional data using NT SVG is included in this trial the difference in risk of graft occlusion between the RA and SV grafts dissipates with there no longer being a significant difference in patency between conduits. The importance of preserving SV structure and the impact of NT harvesting on conduit choice for CABG patients are discussed in this short review
The effects of peer influence on adolescent pedestrian road-crossing decisions
Objective: Adolescence is a high-risk period for pedestrian injury. It is also a time of heightened susceptibility to peer influence. The aim of this research was to examine the effects of peer influence on the pedestrian road-crossing decisions of adolescents.
Methods: Using 10 videos of road-crossing sites, 80 16- to 18-year-olds were asked to make pedestrian road-crossing decisions. Participants were assigned to one of 4 experimental conditions: negative peer (influencing unsafe decisions), positive peer (influencing cautious decisions), silent peer (who observed but did not comment), and no peer (the participant completed the task alone). Peers from the adolescentâs own friendship group were recruited to influence either an unsafe or a cautious decision.
Results: Statistically significant differences were found between peer conditions. Participants least often identified safe road-crossing
sites when accompanied by a negative peer and more frequently identified dangerous road-crossing sites when accompanied by a positive peer. Both cautious and unsafe comments from a peer influenced adolescent pedestriansâ decisions.
Conclusions: These findings showed that road-crossing decisions of adolescents were influenced by both unsafe and cautious comments from their peers. The discussion highlighted the role that peers can play in both increasing and reducing adolescent risk-taking
25 - Identification of Scn1a, Scn2a, and Scn8a in Mammalian Sexual Structures
Ion channels are important membrane bound proteins that are responsible for the the activation and initiation of action potentials in excitable cells. Alterations in function of these channels by mutations have been identified as a cause of several neurological conditions such as epilepsy, ataxia, migraines, and spasms. These conditions are known as channelopathies. Of particular interest is the role that these proteins play in sexual arousal and orgasms. 40-53 percent of American women report sexual dysfunction experienced as loss of libido, lack of arousal, anorgasmia, and sexual pain. In addition, sexual dysfunction is often reported by women with epilepsy and it is often exacerbated by antiepileptic drugs (AEDs). Specifically, common AEDs such as carbamazepine and phenytoin have been reported to impair sexual arousal in patients. This suggests that voltage-gated ion channels genes are good candidate genes for exploring sexual dysfunction conditions. In this study we sought to first examine the specific ion channels present in female C57BL/6 mouse reproductive structures. We looked at three common voltage gated sodium channels found in the central nervous system: Scn1a, Scn2a, and Scn8a. Using the RT-PCR profiler array for neuronal ion channels, we determined the relative expression of these ion channels in crude dissections of mouse sexual organs such as the clitoris, vaginal canal and urethra. Single RT-PCR was then used to confirm the results. Transcripts with â„ 2 fold differences were considered significant. Our results indicates that Scn8a is expressed in female sexual structures, suggesting its role in arousal and/or in the generation of orgasms and the potential for therapeutic intervention
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