A new butterfly-shaped chaotic attractor

AbstractIn this paper, a new chaotic system is proposed that consists of six terms including one multiplier and one quadratic term. The characteristics of this system are examined by theoretical and numerical analysis, such as equilibria, their stabilities, Lyapunov exponents and Lyapunov dimension, dissipativity, as well as, Poincaré maps, bifurcations, waveforms, power spectrums are performed. In addition, the forming mechanisms of compound structures of the new chaotic attractor are investigated

Control and synchronization of the generalized Lorenz system with mismatched uncertainties using backstepping technique and time‐delay estimation

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140007/1/cta2353.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/140007/2/cta2353_am.pd

Multidirectional Instability Accompanying an Inferior Labral Cyst

Paralabral cyst of the shoulder joint can be observed in 2% to 4% of the general population, particularly in men during the third and fourth decade. On average, these cysts measure 10 mm to 20 mm in diameter and are located preferentially on the postero-superior aspect of the glenoid. The MRI has increased the frequency of the diagnosis of paralabral cysts of the shoulder joint. Paralabral cysts of the shoulder joint usually develop in the proximity of the labrum. The relationship between shoulder instability and labral tears is well known, however, the association of shoulder instability with a paralabral cyst is rare. Shoulder instability may cause labral injury or labral injury may cause shoulder instability, and then injured tear develops paralabral cyst. In our patient, the inferior paralabral cyst may be associated with inferior labral tears and instability MRI

A moment closure method for stochastic reaction networks

In this paper we present a moment closure method for stochastically modeled chemical or biochemical reaction networks. We derive a system of differential equations which describes the dynamics of means and all central moments from a chemical master equation. Truncating the system for the central moments at a certain moment term and using Taylor approximation, we obtain explicit representations of means and covariances and even higher central moments in recursive forms. This enables us to deal with the moments in successive differential equations and use conventional numerical methods for their approximations. Furthermore, we estimate the errors in the means and central moments generated by the approximation method. We also find the moments at equilibrium by solving truncated algebraic equations. We show in examples that numerical solutions based on the moment closure method are accurate and efficient by comparing the results to those of stochastic simulation algorithms.open303

Positive and negative switching barriers: promoting hotel customer citizenship behaviour through brand attachment

Purpose This study aims to develop and test a theoretical model postulating that a hotel customer’s brand attachment is reinforced by positive and negative switching barriers, which, in turn, determine customer citizenship behaviour (CCB) towards hotel brands. Design/methodology/approach Surveys were conducted and completed by 233 respondents in the USA who had favourite hotel brands and used these brands in the previous year. A framework was developed based on the literature, and eight hypotheses were tested using structural equation modelling. Findings The findings suggest that a customer’s brand attachment (brand-self connection and brand prominence) to a hotel is strengthened not only by relational benefits (positive switching barriers) but also by switching costs (negative switching barriers). Brand prominence can promote CCB, whereas the impact of brand-self connection on CCB is rather limited. Research limitations/implications This study highlights the importance of affirmative and passive reasons for customers to remain in a relationship with the hotel brand and how sub-dimensions of switching barriers are interrelated to predict a customer’s attitude and behaviour to the brand. By emphasising the role of customers’ hotel brand attachment, this study also ascertains that cognitive and affective bonds towards a hotel brand can be significant antecedents to their extra-role behaviours. Originality/value This research contributes to the hospitality literature by expanding the realm of consumer behaviour research on switching barriers, brand attachment and CCB

Possible link between Arctic Sea ice and January PM10 concentrations in South Korea

In this study, we investigated the possible teleconnection between PM10 concentrations in South Korea and Arctic Sea ice concentrations at inter-annual time scales using observed PM10 data from South Korea, NCEP R2 data, and NOAA Sea Ice Concentration (SIC) data from 2001 to 2018. From the empirical orthogonal function (EOF) analysis, we found that the first mode (TC1) was a large-scale mode for PM10 in South Korea and explained about 27.4% of the total variability. Interestingly, the TC1 is more dominantly influenced by the horizontal ventilation effect than the vertical atmospheric stability effect. The pollution potential index (PPI), which is defined by the weighted average of the two ventilation effects, is highly correlated with the TC1 of PM10 at a correlation coefficient of 0.75, indicating that the PPI is a good measure for PM10 in South Korea at inter-annual time scales. Regression maps show that the decrease of SIC over the Barents Sea is significantly correlated with weakening of high pressure over the Ural mountain range region, the anomalous high pressure at 500 hPa over the Korean peninsula, and the weakening of the Siberian High and Aleutian low. Moreover, these patterns are similar to the correlation pattern with the PPI, suggesting that the variability of SIC over the Barents Sea may play an important role in modulating the variability of PM10 in South Korea through teleconnection from the Barents Sea to the Korean peninsula via Eurasia

Mathematical Modeling of the Impact of Actin and Keratin Filaments on Keratinocyte Cell Spreading

AbstractKeratin intermediate filaments (IFs) form cross-linked arrays to fulfill their structural support function in epithelial cells and tissues subjected to external stress. How the cross-linking of keratin IFs impacts the morphology and differentiation of keratinocytes in the epidermis and related surface epithelia remains an open question. Experimental measurements have established that keratinocyte spreading area is inversely correlated to the extent of keratin IF bundling in two-dimensional culture. In an effort to quantitatively explain this relationship, we developed a mathematical model in which isotropic cell spreading is considered as a first approximation. Relevant physical properties such as actin protrusion, adhesion events, and the corresponding response of lamellum formation at the cell periphery are included in this model. Through optimization with experimental data that relate time-dependent changes in keratinocyte surface area during spreading, our simulation results confirm the notion that the organization and mechanical properties of cross-linked keratin filaments affect cell spreading; in addition, our results provide details of the kinetics of this effect. These in silico findings provide further support for the notion that differentiation-related changes in the density and intracellular organization of keratin IFs affect tissue architecture in epidermis and related stratified epithelia

Early Union of Grafted Bone in Ankylosing Spondylitis: Comparative Study with Degenerative Spinal Disease

Patients with ankylosing spondylitis (AS) achieve early bone union compared to those with other spinal diseases. This study compared the time to bone union after surgery between AS patients and degenerative spinal disease patients. Patients with degenerative spinal diseases (control group) and AS (experimental group) underwent pedicle subtraction osteotomy followed by posterolateral fusion, and decompression and posterolateral fusion, respectively. There were 10 patients in the experimental group. The control group included 26 patients who were less than 50 years of age and underwent two-level autogenous grafting after decompression and spinal fusion. Autogenous grafts and a range of bone substitutes were used in the experimental group, whereas only autogenous grafts were used in the control group. Bone union was determined on the radiographs and 3-dimensional CT scan images. The level of union was assessed using the Lenke's and Christensen's classification systems. In the experimental group, the mean age was 41.3 years (range, 30 to 67 years), the mean follow-up period was 21.7 months (range, 12 to 43 months), and bone union was confirmed at an average of 3.5 months (range, 3 to 5 months) after surgery. In the control group, the mean age was 43.1 years (range, 35 to 50 years), the mean follow-up period was 21.8 months (range, 12 to 74 months), and bone union was observed at an average of 5.6 months (range, 4 to 12 months) after surgery. The difference in the time to bone union between the two groups was significant (p = 0.023). The union of grafted bone was obtained earlier in patients with AS than in those with degenerative spinal diseases. Therefore, future studies should examine the factors affecting the early union in AS patients