2,693 research outputs found

    Local diffusion theory of localized waves in open media

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    We report a first-principles study of static transport of localized waves in quasi-one-dimensional open media. We found that such transport, dominated by disorder-induced resonant transmissions, displays novel diffusive behavior. Our analytical predictions are entirely confirmed by numerical simulations. We showed that the prevailing self-consistent localization theory [van Tiggelen, {\it et. al.}, Phys. Rev. Lett. \textbf{84}, 4333 (2000)] is valid only if disorder-induced resonant transmissions are negligible. Our findings open a new direction in the study of Anderson localization in open media.Comment: 4 pages, 2 figure

    Self organized criticality in an improved Olami-Feder-Christensen model

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    An improved version of the Olami-Feder-Christensen model has been introduced to consider avalanche size differences. Our model well demonstrates the power-law behavior and finite size scaling of avalanche size distribution in any range of the adding parameter paddp_{add} of the model. The probability density functions (PDFs) for the avalanche size differences at consecutive time steps (defined as returns) appear to be well approached, in the thermodynamic limit, by q-Gaussian shape with appropriate q values which can be obtained a priori from the avalanche size exponent τ\tau. For the small system sizes, however, return distributions are found to be consistent with the crossover formulas proposed recently in Tsallis and Tirnakli, J. Phys.: Conf. Ser. 201, 012001 (2010). Our results strengthen recent findings of Caruso et al. [Phys. Rev. E 75, 055101(R) (2007)] on the real earthquake data which support the hypothesis that knowing the magnitude of previous earthquakes does not make the magnitude of the next earthquake predictable. Moreover, the scaling relation of the waiting time distribution of the model has also been found.Comment: 16 pages, 6 figure

    Overexpression of an isoform of AML1 in acute leukemia and its potential role in leukemogenesis

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    AML1/RUNX1 is a critical transcription factor in hematopoietic cell differentiation and proliferation. From the _AML1_ gene, at least three isoforms, _AML1a_, _AML1b_ and _AML1c_, are produced through alternative splicing. AML1a interferes with the function of AML1b/1c, which are often called AML1. In the current study, we found a higher expression level of _AML1a_ in ALL patients in comparison to the controls. Additionally, AML1a represses transcription from promotor of macrophage-colony simulating factor receptor (M-CSFR) mediated by AML1b, indicating that AML1a antagonized the effect of AML1b. In order to investigate the role of _AML1a_ in hematopoiesis and leukemogenesis _in vivo_, bone marrow mononuclear cells (BMMNCs) from mice were transduced with AML1a and transplanted into lethally irradiated mice, which develop lymphoblastic leukemia after transplantation. Taken together, these results indicate that overexpression of AML1a may be an important contributing factor to leukemogenesis

    Topologically Protected Metastable States in Classical Dynamics

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    We propose that the domain walls formed in a classical Ginzburg-Landau model can exhibit topologically stable but thermodynamically metastable states. This proposal relies on Allen-Cahn's assertion that the velocity of domain wall at some point is proportional to the mean curvature at that point. From this assertion we speculate that domain wall resembles a rubber band that can winds the background geometry in a nontrivial way and can exist permanently. We numerically verify our proposal in two and three spatial dimensions by using periodic boundary conditions as well as Neumann boundary conditions. We find that there are always possibilities to form topologically stable domain walls in the final equilibrium states. However, from the aspects of thermodynamics these topologically nontrivial domain walls have higher free energies and are thermodynamically metastable. These metastable states that are protected by topology could potentially serve as storage media in the computer and information technology industry.Comment: 5 pages, 4 figure

    脑卒中后遗症期患者社区康复评定量表选择初探

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    Objective: To choose the scales that can comprehensively assess the function of patients with stroke sequelae for the grassroots medical staff. Methods: The commonly used scales were selected. The patients with stroke sequelae were assessed by the MOS item short from health survey(SF-36), Modified Barthel Index(MBI), Brain Injury Community Rehabilitation Outcome Scales(BICRO-39),WHO Disability Assessment Scale II(WHO-DAS II) and Anxiety and Depression Self-rating Scales(SAS and SDS). The assessment datum was conducted by Pearson correlation coefficient. Results: The data of MBI have significant correlation among the datum of WHO-DASII, SF-36 and BICRO 39 scales(P<0.05). The datum of MBI doesn’t have correlation among the datum of the SAS and SDS (P>0.05). Conclusions: Community doctors can choose MBI which can effectively assess the activities of daily living for the community patients with stroke sequelae. MBI also can reflect the functional levels of community patients with stroke sequelae.目的:为基层医务人员选择综合科学评价脑卒中后遗症期患者的功能水平的量表。方法:选择常用的量表:简明健康状况调查表SF-36量表、改良Barthel指数评分标准、脑损伤社区康复结果量表(BICRO-39 scales)、世界卫生组织残疾评定量表(WHODASII)、焦虑抑郁自评量表(SAS & SDS)在内的六个量表的数据采集,分别与改良Barthel指数评分标准进行皮尔森相关系数(Pearson correlation coefficient)分析。结果:BI的测评结果与WHODAS II、SF-36、BICRO-39的测评结果显著相关(P值<0.05);而与SAS及SDS的测评结果不相关(P>0.05)。结论:基层医生可以选择BI量表对脑卒中后遗症患者的日常生活活动能力进行评定;BI量表也可以进一步反映脑卒中后遗症患者的功能水平

    Study on the Modified triphenyl tetrazolium chloride – dehydrogenase activity (TTC-DHA) Method in Determination of bioactivity in the up-flow aerated bio-activated carbon filter

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    The study applied triphenyl tetrazolium chloride-dehydrogenase activity (TTC-DHA) method to detect the activities of attached biofilm on bio-activated carbon (BAC) samples in the up-flow aerated biological activated carbon filter (UABACF) treating textile secondary effluent. Modification to the conventional TTC-DHA determination method was proposed. In the modification, BAC samples were used directly to measure TTC-DHA without pre-separating the attached biofilm from carbon samples. After modification, the mean values of biofilm TTC-DHA activities for the BAC samples at different heights of the biofilter were 25 to 193 times higher than those measured in conventional way. In addition, the microbial activity distribution related more closely to substrate removal along the height of the reactor after modification. The results indicated that high activity of the bacteria that are firmly fixed on the porous surface of the media would be ignored during pre-separation of the attached biofilm from media surface. The study also indicated the influence of granular activated carbon (GAC) adsorption on the bio-activity of attached biofilm. GAC adsorption was favorable in the improvement of the activities within the biofilter, especially when the attached films were destroyed. The modification of TTC-DHA determination method made this technique more convenient and accurate in activity measurement of biofilm fixed on porous surface structured activated carbon.Keywords: Up-flow, aerated bio-filter, BAC, TTC-DHA, bioactivit

    Research on Traffic Optimization of Urban Four-Phase Intersections Based on VISSIM

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    In order to effectively solve the congestion problem of mixed intersections, improve traffic efficiency, and improve the current congestion situation of urban road network, this paper takes the mixed traffic flow intersection of Shanghai Road and Guyan Street in Yuanzhou District of Guyuan City as an example to carry out optimization research, collect traffic flow and signal timing data during peak hours through field investigation, and establish a microscopic road model by using VISSIM software. Through simulation, the indexes such as vehicle delay and queue length are obtained. Then the lane function of the model is divided, the signal timing is optimized by Webster algorithm and Fuzzy algorithm, and the comparison analysis is carried out. The simulation results show that the vehicle delay and queue length after Fuzzy optimization are greatly reduced, and the traffic running condition is significantly improved, thus verifying the scientificity and rationality of the optimization scheme
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