Feeling Right at Home: Hometown CEOs and Firm Innovation

Extending the theories of social and place identity, we predict that CEO hometown identity has a positive and significant influence on firm innovation. Our empirical evidence, from publicly traded firms in China during 2002–2016, suggests that a firm whose CEO's hometown is in the same province or city as the firm's headquarters tends to invest more in R&D and generate more patent applications. Our results are robust to the firm fixed effects and we use difference-in-differences analysis and instrument variable regressions to mitigate endogeneity concerns. CEOs' hometown identity still has a strong and positive impact on innovation after we control for measures of social capital of CEOs. We identify the mechanisms behind the positive relation between firm innovation and CEO hometown identity: hometown CEOs enjoy more support from the board of directors, they are more willing to take risks, and they are more likely to have long-term visions

Mechanical deformation mechanism and verification of sections at junctions of light and dark tunnel in a mountain area

Projects involving junctions of light and dark tunnel in mountainous areas are complex engineering problems that combine tunnel structure, slope rock-soil mass and protection projects. Such junctions suffer from a complex and changeable load. The stress and deformation of the junction varies under different conditions. Thus, it is a major source of inconvenience for construction and monitoring operations. In this paper, according to the load conditions at a junction of light and dark tunnel, we divide the junction hole into thrust, compression, and combined thrust-compression types. Three types of structures were simulated by numerical analysis, and we explored the structural deformation and stress of these types of tunnel under different condition. Thus, in any construction process, the mechanical deformation mechanism and the weak point in the structure should be worked out. Based on the weak parts, some monitoring points were installed, and four fields for monitoring were chosen. The monitoring results show that the actual deformation, stress and structural failure location are basically consistent with the numerical simulation results. The deformation mechanism of light and dark tunnel junction obtained can provide the basis for selecting the treatment measures and controlling the structural deformation. Furthermore, the results can also be used as a reference for similar engineering design, construction and site monitoring projects

An Image-Based Finite Element Approach for Simulating Viscoelastic Response of Asphalt Mixture

This paper presents an image-based micromechanical modeling approach to predict the viscoelastic behavior of asphalt mixture. An improved image analysis technique based on the OTSU thresholding operation was employed to reduce the beam hardening effect in X-ray CT images. We developed a voxel-based 3D digital reconstruction model of asphalt mixture with the CT images after being processed. In this 3D model, the aggregate phase and air void were considered as elastic materials while the asphalt mastic phase was considered as linear viscoelastic material. The viscoelastic constitutive model of asphalt mastic was implemented in a finite element code using the ABAQUS user material subroutine (UMAT). An experimental procedure for determining the parameters of the viscoelastic constitutive model at a given temperature was proposed. To examine the capability of the model and the accuracy of the parameter, comparisons between the numerical predictions and the observed laboratory results of bending and compression tests were conducted. Finally, the verified digital sample of asphalt mixture was used to predict the asphalt mixture viscoelastic behavior under dynamic loading and creep-recovery loading. Simulation results showed that the presented image-based digital sample may be appropriate for predicting the mechanical behavior of asphalt mixture when all the mechanical properties for different phases became available

Analytical analyses of the effect of filled karst cavern on tunnel lining structure under complex geological conditions

In this study, based on the elastic foundation beam theory, a local elastic foundation model has been developed. Using the model, the mechanical characteristics of the effect of tunnel-filled karst on the lining structure has been investigated. Incorporating the characteristic of the karst area, the formulas for the displacement, bending moment, and shear force of an equivalent beam have been derived. By applying the formulas to a beam under different working conditions, such as different cavern sizes and different compression modulus ratios of the filling media, analyses of the mechanical states have been carried out. The results show that if the compression modulus ratio of different filling media is close to unity, the effect of the cave on the lining structure is very small. On the other hand, if the ratio is much less than unity, the effect is more significant. The effect on the stability of the lining structure is greater for the larger caves, and smaller for the smaller caves. For the tunnel bottom equivalent beam, its bending point is at the point where the cave is in contact with the surrounding rock. Further, the maximum shear force is at the contact surface. For a beam that is closer to the karst, the displacement is larger. Under this situation, the beam section is in an adverse force state and prone to cracks. The results from this study can be used as a significant guide for the design, maintenance and construction of a tunnel which has a cavern at the base of the tunnel

Microstructural Modeling of Rheological Mechanical Response for Asphalt Mixture Using an Image-Based Finite Element Approach

In this paper, an image-based micromechanical model for an asphalt mixture’s rheological mechanical response is introduced. Detailed information on finite element (FE) modeling based on X-ray computed tomography (X-ray CT) is presented. An improved morphological multiscale algorithm was developed to segment the adhesive coarse aggregate images. A classification method to recognize the different classifications of the elemental area for a confining pressure purpose is proposed in this study. Then, the numerical viscoelastic constitutive formulation of asphalt mortar in an FE code was implemented using the simulation software ABAQUS user material subroutine (UMAT). To avoid complex experiments in determining the time-dependent Poisson’s ratio directly, numerous attempts were made to indirectly obtain all material properties in the viscoelastic constitutive model. Finally, the image-based FE model incorporated with the viscoelastic asphalt mortar phase and elastic aggregates was used for triaxial compressive test simulations, and a triaxial creep experiment under different working conditions was conducted to identify and validate the proposed finite element approach. The numerical simulation and experimental results indicate that the three-dimensional microstructural numerical model established can effectively analyze the material’s rheological mechanical response under the effect of triaxial load within the linear viscoelastic range

Local–Migrant Interaction in Everyday Life in an Ancient Tourism Town

Daily interaction is a primary means of understanding social change which is of vital importance for community well-being. In tourism host communities, daily interactions among different resident groups reflect tourism’s effects which are directly related to tourists’ experiences and community harmony. In this exploratory article, grounded theory was applied to analyze daily interactions between locals and migrants in Zhouzhuang, the first ancient tourism town in China, based on in-depth interviews. A model framework was also constructed. The results pinpoint subjective interaction intention and objective interaction opportunities as two influencing factors which operate reciprocally and directly influence locals’ and migrants’ daily interactions. The findings suggest that many locals and migrants experience clear communication boundaries in daily interactions. Both groups’ subjective interaction intentions were influenced by their cultural backgrounds, group perceptions, and original social networks, all of which are difficult to modify within a short time. Therefore, increasing objective communication opportunities is a key way to promote intergroup interaction and integration. These findings provide theoretical and practical implications for tourism host communities’ well-being and sustainable development

Specific Multilocus Variable-Number Tandem-Repeat Analysis Genotypes of <i>Mycoplasma pneumoniae</i> Are Associated with Diseases Severity and Macrolide Susceptibility

<div><p>Clinical relevance of multilocus variable-number tandem-repeat (VNTR) analysis (MLVA) in patients with community-acquired pneumonia (CAP) by <i>Mycoplasma pneumoniae</i> (<i>M. pneumoniae</i>) is unknown. A multi-center, prospective study was conducted from November 2010 to April 2012. Nine hundred and fifty-four CAP patients were consecutively enrolled. <i>M. pneumoniae</i> clinical isolates were obtained from throat swabs. MLVA typing was applied to all isolates. Comparison of pneumonia severity index (PSI) and clinical features among patients infected with different MLVA types of <i>M. pneumoniae</i> were conducted. One hundred and thirty-six patients were positive with <i>M. pneumoniae</i> culture. The clinical isolates were clustered into 18 MLVA types. One hundred and fourteen (88.3%) isolates were resistant to macrolide, covering major MLVA types. The macrolide non-resistant rate of <i>M. pneumoniae</i> isolates with Mpn13-14-15-16 profile of 3-5-6-2 was significantly higher than that of other types (p≤0.001). Patients infected with types U (5-4-5-7-2) and J (3-4-5-7-2) had significantly higher PSI scores (p<0.001) and longer total duration of cough (p = 0.011). Therefore it seems that there is a correlation between certain MLVA types and clinical severity of disease and the presence of macrolide resistance.</p></div

Dendritic Spine in Autism Genetics: Whole-Exome Sequencing Identifying De Novo Variant of <i>CTTNBP2</i> in a Quad Family Affected by Autism Spectrum Disorder

Autism spectrum disorder (ASD) affects around 1% of children with no effective blood test or cure. Recent studies have suggested that these are neurological disorders with a strong genetic basis and that they are associated with the abnormal formation of dendritic spines. Chromosome microarray (CMA) together with high-throughput sequencing technology has been used as a powerful tool to identify new candidate genes for ASD. In the present study, CMA was first used to scan for genome-wide copy number variants in a proband, and no clinically significant copy number variants were found. Whole-exome sequencing (WES) was used further for genetic testing of the whole quad family affected by ASD, including the proband, his non-autistic sister, and his parents. Sanger sequencing and MassARRAY-based validation were used to identify and confirm variants associated with ASD. WES yielded a 151-fold coverage depth for each sample. A total of 98.65% of the targeted whole-exome region was covered at >20-fold depth. A de novo variant in CTTNBP2, p.M115T, was identified. The CTTNBP2 gene belongs to a family of ankyrin repeat domain-containing proteins associated with dendritic spine formation. Although CTTNBP2 has been associated with ASD, limited studies have been developed to identify clinically relevant de novo mutations of CTTNBP2 in children with ASD; family-based WES successfully identified a clinically relevant mutation in the CTTNBP2 gene in a quad family affected by ASD. Considering the neuron-specific expression of CTTNBP2 and its role in dendritic spine formation, our results suggest a correlation between the CTTNBP2 mutation and ASD, providing genetic evidence for ASD spine pathology. Although the present study is currently insufficient to support the assertion that the de novo mutation M115T in CTTNBP2 directly causes the autism phenotype, our study provides support for the assertion that this mutation is a candidate clinically relevant variant in autism