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

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 $p_{add}$ 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 $\tau$. 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

Governance Mechanism of E-health in Chinese Urban Communities: The Case of Zhabei District in Shanghai

E-health governance can be divided into four kinds of models: government-oriented, market-oriented, government-market cooperation, and multi-collaborative governance. With the development of market economy, democratic consciousness and management philosophy, traditional e-health management faces many challenges. And multi-collaborative governance model is becoming a good choice for the community e-health. In order to further analyze the characteristics and applicability of this model and explore the sustainable development path, this paper selects Zhabei District as a typical case and distinguishes the roles of different governance bodies in community e-health. By this study, we recognize that the e-health governance of Chinese urban community has some problems, such as, insufficient involvement of non-governmental body, obvious conflict of interest and the lack of collaboration among the various subjects. Therefore, it is supposed to construct an integrated e-health development mechanism. Based on collaborative governance theory, the mechanism has to follow three basic principles. At the same time, effective operation of this mechanism need five mechanisms which include trust, communication and negotiation, cost sharing, supervision and feedback. Key words: community e-health, collaborative governance, medical service, Zhabei Distric

Estudio piloto de intervención de enfermería radiológica en examen de resonancia magnética 3-t

OBJETIVO Se objetivó investigar el efecto de la intervención de enfermería radiológica en examen abdominal de IRM 3-T. MÉTODO Sesenta pacientes con enfermedades abdominales fueron divididos aleatoriamente en dos grupos: grupo intervención de enfermería RM y grupo control. Todos fueron sometidos a examen abdominal de RM 3-T. Las intervenciones de enfermería RM se efectuaron en el grupo establecido. Los resultados, incluyendo tasa de éxito en única vez, relación de imágenes de RM diagnosticables y puntos de calidad de imagen, fueron comparadas entre ambos grupos. RESULTADOS La tasa de éxito en única vez en grupo control y grupo intervención de enfermería RM fueron de 66,67% y 96,67%, expresando diferencias significativas (χ2 =9.017, POBJETIVO O objetivo deste estudo foi investigar o resultado da intervenção de enfermagem na radiologia em exame de ressonância magnética (RM) abdominal 3 Tesla. MÉTODO 60 pacientes com patologias abdominais foram aleatoriamente divididos em dois grupos: grupo de intervenção de enfermagem em RM e grupo controle. Todos os pacientes foram submetidos ao exame de RM abdominal 3 Tesla. As intervenções de enfermagem em RM foram realizadas no grupo de intervenção de enfermagem. Os resultados foram comparados entre os dois grupos, incluindo a taxa de sucesso único, o coeficiente das imagens de RM diagnosticáveis e os pontos da qualidade de imagem. RESULTADOS As taxas de sucesso único no grupo controle e no grupo de intervenção de enfermagem em RM foram 66,67% e 96,67%, com diferença significativa de (χ2 =9,017, POBJECTIVE The aim of this study was to investigate the effect of radiology nursing intervention in abdominal examination at 3-T MRI. METHOD 60 patients with abdominal diseases were divided into two groups randomly: MR nursing intervention group and control group. All the patients underwent abdominal MR examination at 3-T. The MR nursing interventions were performed in nursing intervention group. The outcomes, including one-time success rate, the ratio of diagnosable MR images and the points of image quality, were compared between these two groups. RESULTS The one-time success rates in control group and MR nursing intervention group were 66.67% and 96.67% with significant difference ( χ2 =9.017,

Numerical simulation on the impact dynamics of a novel rotation air hammer and experimental research

Novel rotation air hammer (NRAH) is a rock-breaking tool in the gas drilling. The rock-breaking ability of the NRAH is mainly from the collision between piston and drill bit in it. The collision makes the piston and the drill bit suffer from a high instantaneous impact stress, so that they are prone to failure. Thus, both of them are not only the most crucial parts of the NRAH, but also the easily damaged parts. So it is necessary to analyze the impact stress in them and optimize their structure to improve the security and reliability. First of all, we analyzed the working mechanism of the NRAH to understand motion and structure of the piston and the drill bit. Then we used the LS-DYNA program to analyze impact dynamics problem of the piston and the drill bit to obtain their stress change rule in the impact process. According to the structure optimization, the security coefficient of the piston and the drill bit has been obviously improved. Moreover, their energy conversion regulations were studied in the impact process of the NRAH and the last impacting velocity of the piston was computed, which can provide helpful for effective application of this tool in the field. Finally, based on the experimental study on the NRAH after the optimization, we found that its function had satisfied the design requirements as well as overall performance was improved

Ethyl 6-methyl-2-p-tolyl­pyrazolo[1,5-a]pyridine-5-carboxyl­ate

In the title mol­ecule, C18H18N2O2, the bicyclic ring system and the benzene ring form a dihedral angle of 13.45 (3)°. In the crystal structure, weak inter­molecular C—H⋯O hydrogen bonds link mol­ecules into chains propagated along [201]

Dynamical encircling exceptional point in largely detuned multimode optomechanical system

Dynamical encircling exceptional point(EP) shows a number of intriguing physical phenomena and its potential applications. To enrich the manipulations of optical systems in experiment, here, we study the dynamical encircling EP, i.e. state transfer process, in largely detuned multimode optomechanical system. The process of state transfer has been investigated with different factors about the location of start point, the orientation and the initial state of the trajectories around the EP in parameter space. Results show that the nonreciprocal and the chiral topological energy transfer between two optical modes are performed successfully by tuning the effective optomechanical coupling in the multimode system with large detuning. Moreover, the factor of evolution speed about system parameters is also discussed. Our work demonstrates the fundamental physics around EP in large detuning domain of multimode optomechanical system and provides an alternative for manipulating of optical modes in non-hermitian system.Comment: 9 pages,7 figure

Enhanced sensing mechanism based on shifting an exceptional point

Non-Hermitian systems associated with exceptional points (EPs) are expected to demonstrate a giant response enhancement for various sensors. The widely investigated enhancement mechanism based on diverging from an EP should destroy the EP and further limits its applications for multiple sensing scenarios in a time sequence. To break the above limit, here we proposed a new enhanced sensing mechanism based on shifting an EP. Different from the mechanism of diverging from an EP, our scheme is an EP non-demolition and the giant enhancement of response is acquired by a slight shift of the EP along the parameter axis induced by perturbation. The new sensing mechanism can promise the most ffective response enhancement for all sensors in the case of multiple sensing in a time sequence. To verify our sensing mechanism, we construct a mass sensor and a gyroscope with concrete physical implementations. Our work will deepen the understanding of EP-based sensing and inspire designing various high sensitivity sensors in different physical systems.Comment: 7 pages, 3 figure

HIF-1α Contributes to Hypoxia-induced Invasion and Metastasis of Esophageal Carcinoma via Inhibiting E-cadherin and Promoting MMP-2 Expression

Hypoxia-inducible factor-1α (HIF-1α) has been found to enhance tumor invasion and metastasis, but no study has reported its action in esophageal carcinoma. The goal of this study was to explore the probable mechanism of HIF-1α in the invasion and metastasis of esophageal carcinoma Eca109 cells in vitro and in vivo. mRNA and protein expression of HIF-1α, E-cadherin and matrix metalloproteinase-2 (MMP-2) under hypoxia were detected by RT-PCR and Western blotting. The effects of silencing HIF-1α on E-cadherin, MMP-2 mRNA and protein expression under hypoxia or normoxia were detected by RT-PCR and Western blotting, respectively. The invasive ability of Eca109 cells was tested using a transwell chambers. We established an Eca109-implanted tumor model and observed tumor growth and lymph node metastasis. The expression of HIF-1α, E-cadherin and MMP-2 in xenograft tumors was detected by Western blotting. After exposure to hypoxia, HIF-1α protein was up-regulated, both mRNA and protein levels of E-cadherin were down-regulated and MMP-2 was up-regulated, while HIF-1α mRNA showed no significant change. SiRNA could block HIF-1α effectively, increase E-cadherin expression and inhibit MMP-2 expression. The number of invading cells decreased after HIF-1α was silenced. Meanwhile, the tumor volume was much smaller, and the metastatic rate of lymph nodes and the positive rate were lower in vivo. Our observations suggest that HIF-1α inhibition might be an effective strategy to weaken invasion and metastasis in the esophageal carcinoma Eca109 cell line