2,755 research outputs found

    Self-organization and phase transition in financial markets with multiple choices

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    Market confidence is essential for successful investing. By incorporating multi-market into the evolutionary minority game, we investigate the effects of investor beliefs on the evolution of collective behaviors and asset prices. When there exists another investment opportunity, market confidence, including overconfidence and under-confidence, is not always good or bad for investment. The roles of market confidence is closely related to market impact. For low market impact, overconfidence in a particular asset makes an investor become insensitive to losses and a delayed strategy adjustment leads to a decline in wealth, and thereafter, one's runaway from the market. For high market impact, under-confidence in a particular asset makes an investor over-sensitive to losses and one's too frequent strategy adjustment leads to a large fluctuation in asset prices, and thereafter, a decrease in the number of agents. At an intermediate market impact, the phase transition occurs. No matter what the market impact is, an equilibrium between different markets exists, which is reflected in the occurrence of similar price fluctuations in different markets. A theoretical analysis indicates that such an equilibrium results from the coupled effects of strategy updating and shift in investment. The runaway of the agents trading a specific asset will lead to a decline in the asset price volatility and such a decline will be inhibited by the clustering of the strategies. A uniform strategy distribution will lead to a large fluctuation in asset prices and such a fluctuation will be suppressed by the decrease in the number of agents in the market. A functional relationship between the price fluctuations and the numbers of agents is found

    Coupled effects of local movement and global interaction on contagion

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    By incorporating segregated spatial domain and individual-based linkage into the SIS (susceptible-infected-susceptible) model, we investigate the coupled effects of random walk and intragroup interaction on contagion. Compared with the situation where only local movement or individual-based linkage exists, the coexistence of them leads to a wider spread of infectious disease. The roles of narrowing segregated spatial domain and reducing mobility in epidemic control are checked, these two measures are found to be conducive to curbing the spread of infectious disease. Considering heterogeneous time scales between local movement and global interaction, a log-log relation between the change in the number of infected individuals and the timescale τ\tau is found. A theoretical analysis indicates that the evolutionary dynamics in the present model is related to the encounter probability and the encounter time. A functional relation between the epidemic threshold and the ratio of shortcuts, and a functional relation between the encounter time and the timescale τ\tau are found

    Overexpression of soybean ubiquitin-conjugating enzyme gene GmUBC2 confers enhanced drought and salt tolerance through modulating abiotic stress-responsive gene expression in Arabidopsis

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    Previous studies have shown that ubiquitination plays important roles in plant abiotic stress responses. In the present study, the ubiquitin-conjugating enzyme gene GmUBC2, a homologue of yeast RAD6, was cloned from soybean and functionally characterized. GmUBC2 was expressed in all tissues in soybean and was up-regulated by drought and salt stress. Arabidopsis plants overexpressing GmUBC2 were more tolerant to salinity and drought stresses compared with the control plants. Through expression analyses of putative downstream genes in the transgenic plants, we found that the expression levels of two ion antiporter genes AtNHX1 and AtCLCa, a key gene involved in the biosynthesis of proline, AtP5CS, and the copper chaperone for superoxide dismutase gene AtCCS, were all increased significantly in the transgenic plants. These results suggest that GmUBC2 is involved in the regulation of ion homeostasis, osmolyte synthesis, and oxidative stress responses. Our results also suggest that modulation of the ubiquitination pathway could be an effective means of improving salt and drought tolerance in plants through genetic engineering

    Lifespan Intellectual Factors, Genetic Susceptibility, and Cognitive Phenotypes in Aging: Implications for Interventions

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    Along with rapid global population aging, the age-related cognitive disorders such as mild cognitive impairment (MCI) and dementia have posed a serious threat to public health, health care system, and sustainable economic and societal development of all countries. In this narrative review, we seek to summarize the major epidemiological studies from the life-course perspective that investigate the influence of genetic susceptibility [e.g., apolipoprotein (APOE) ε4 allele] and intellectual or psychosocial factors (e.g., educational attainments and leisure activities) as well as their interactions on cognitive phenotypes in aging. Numerous population-based studies have suggested that early-life educational attainments and socioeconomic status, midlife work complexity and social engagements, late-life leisure activities (social, physical, and mentally-stimulating activities), certain personality traits (e.g., high neuroticism and low conscientiousness), and depression significantly affect late-life cognitive phenotypes. Furthermore, certain intellectual or psychosocial factors (e.g., leisure activities and depression) may interact with genetic susceptibility (e.g., APOE ε4 allele) to affect the phenotypes of cognitive aging such that risk or beneficial effects of these factors on cognitive function may vary by carrying the susceptibility genes. Current evidence from the randomized controlled trials that support the cognitive benefits of cognitive training among cognitive healthy older adults remains limited. The cognitive reserve hypothesis has been proposed to partly explain the beneficial effects of lifetime intellectual and psychosocial factors on late-life cognitive function. This implies that, from a life-course perspective, preventive intervention strategies targeting multiple modifiable intellectual and psychosocial factors could interfere with clinical expression of cognitive disorders in old age and delay the onset of dementia syndrome, and thus, may help achieve healthy brain aging

    Ionic Liquid Pilocarpine Analog as an Antiglaucoma Drug Candidate

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    Ionic liquid pilocarpine analog [Pilo-OEG]Cl, the first-of-its-kind ionic liquid antiglaucoma drug candidate, is synthesized and reported. To synthesize [Pilo-OEG]Cl, pilocarpine was reacted with the oligo-polyethylene glycol chloride, 2-[2-(2-chloroethoxy)ethoxy] ethanol, to form an ionic liquid molecule with an imidazole cation and a chloride anion. The chemical structure of [Pilo-OEG]Cl was confirmed with 1H NMR spectroscopy. Compared with pilocarpine (Pilo) and pilocarpine hydrochloride (PiloHCl), [Pilo-OEG]Cl has improved structural stability according to pH measurements and LC-MS analysis. The corneal permeability coefficient of [Pilo-OEG]Cl is 2-fold higher than that of Pilo and 8-fold higher than that of PiloHCl. [Pilo-OEG]Cl does not show apparent toxicity to human corneal epithelial cells over a broad range of concentrations up to 50 mM. The in vivo efficacy of PiloHCl and [Pilo-OEG]Cl was tested in normotensive adult Brown Norway female rats. [Pilo-OEG]Cl is found to be more potent than PiloHCl in lowering the intraocular pressure (IOP). [Pilo-OEG]Cl is more cytocompatible than PiloHCl based on the in vitro ELISA and hemolysis tests and in vivo histological analysis. Taken together, [Pilo-OEG]Cl has enhanced stability, corneal permeability, better IOP-lowering efficacy, and improved biocompatibility, thus making it a promising new drug candidate for antiglaucoma therapy. Transforming old antiglaucoma drugs to pharmaceutically active ionic liquids represents an innovative approach to developing glaucoma medications

    A generalized public goods game with coupling of individual ability and project benefit

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    Facing a heavy task, any single person can only make a limited contribution and team cooperation is needed. As one enjoys the benefit of the public goods, the potential benefits of the project are not always maximized and may be partly wasted. By incorporating individual ability and project benefit into the original public goods game, we study the coupling effect of the four parameters, the upper limit of individual contribution, the upper limit of individual benefit, the needed project cost and the upper limit of project benefit on the evolution of cooperation. Coevolving with the individual-level group size preferences, an increase in the upper limit of individual benefit promotes cooperation while an increase in the upper limit of individual contribution inhibits cooperation. The coupling of the upper limit of individual contribution and the needed project cost determines the critical point of the upper limit of project benefit, where the equilibrium frequency of cooperators reaches its highest level. Above the critical point, an increase in the upper limit of project benefit inhibits cooperation. The evolution of cooperation is closely related to the preferred group-size distribution. A functional relation between the frequency of cooperators and the dominant group size is found

    Relation between axial length and ocular parameters

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    AIM: To investigatethe relation between axial length(AL), age and ocular parameters.<p>METHODS: A total of 360 subjects(360 eyes)with emmetropia or myopia were recruited. Refraction, center corneal thickness(CCT), AL, intraocular pressure(IOP)were measured by automatic-refractor, Pachymeter, A-mode ultrasound and non-contact tonometer, respectively. Corneal curvature(CC), anterior chamber depth(ACD)and white-to-white distance(WWD)were measured by Orbscan II. Three dimensional frequency domain coherent optical tomography(3D-OCT)was used to examine the retinal nerve fiber layer thickness(RNFLT). The Pearson correlation coefficient(<i>r</i>)and multiple regression analysis were performed to evaluate the relationship between AL, age and ocular parameters.<p>RESULTS: The average AL was 24.15±1.26mm. With elongation of the AL, spherical equivalent(SE)(<i>r</i>=-0.742,<i>P</i><0.01), CC(<i>r</i>=-0.395, <i>P</i><0.01)and RNFLT(<i>r</i>=-0.374, <i>P</i><0.01)all decreased, while the mean ACD(<i>r</i>=0.411, <i>P</i><0.01)increased. On the contrary, there was not statistical significan with CCT(<i>r</i>=0.099, <i>P</i>=0.060)and WWD(<i>r</i>=0.061, <i>P</i>=0.252). There was also a significant correlation between AL and age(<i>P</i>=0.001), SE(<i>P</i><0.001), ACD(<i>P</i><0.001), CC(<i>P</i><0.001)in Multiple linear regression analysis.<p>CONCLUSION: In longer eyes, there is a tendency toward myopia, a flatter cornea, a deeper ACD and a thinner RNFLT. Age is an influencing factor for the AL as well
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