Anisotropic power-law inflation for a conformal-violating Maxwell model

A set of power-law solutions of a conformal-violating Maxwell model with a non-standard scalar-vector coupling will be shown in this paper. In particular, we are interested in a coupling term of the form $X^{2n} F^{\mu\nu}F_{\mu\nu}$ with $X$ denoting the kinetic term of the scalar field. Stability analysis indicates that the new set of anisotropic power-law solutions is unstable during the inflationary phase. The result is consistent with the cosmic no-hair conjecture. We show, however, that a set of stable slowly expanding solutions does exist for a small range of parameters $\lambda$ and $n$. Hence a small anisotropy can survive during the slowly expanding phase.Comment: 13 pages with 3 figure

Multiple Quantum Phases in Graphene with Enhanced Spin-Orbit Coupling: From the Quantum Spin Hall Regime to the Spin Hall Effect and a Robust Metallic State

We report an intriguing transition from the quantum spin Hall phase to the spin Hall effect upon segregation of thallium adatoms adsorbed onto a graphene surface. Landauer-B\"uttiker and Kubo-Greenwood simulations are used to access both edge and bulk transport physics in disordered thallium-functionalized graphene systems of realistic sizes. Our findings not only quantify the detrimental effects of adatom clustering in the formation of the topological state, but also provide evidence for the emergence of spin accumulation at opposite sample edges driven by spin-dependent scattering induced by thallium islands, which eventually results in a minimum bulk conductivity $\sim 4e^{2}/h$, insensitive to localization effects

Are Urban Consumers in China Ready to Accept Biotech Foods?

Based on a large-scale survey conducted in 11 large and small eastern cities in 2002, this study employs ordered probit models to estimate the effects of demographic and socio-economic variables on the likelihood of biotech food acceptance in China. This study also employs a dichotomous choice model to estimate consumers' mean willingness to pay (WTP) for biotech foods, including soybean oil and insect-resistant biotech rice. This survey reaffirms that Chinese urban consumers had a low awareness of biotechnology. Despite the low level of awareness, a great majority of respondents had favorable or neutral attitudes toward biotech foods. Only 5-15 percent was strongly or relatively opposed to biotech foods. Results from the models suggest that mid- and small-city consumers were more supportive of the use of biotech foods than large-city consumers. In addition, consumers with poorer health were less willing to accept biotech foods. Those consumers who trusted the accuracy of media information were also more willing to accept biotech foods. A majority-60 percent or higher-of the respondents were willing to purchase biotech foods without any price discounts. However, about 20 percent would only accept non-biotech foods. Results of the WTP analysis suggest that the likely price premiums that respondents are willing to pay for non-biotech foods averaged around 23.4 percent in the case of soybean oil and 41.5 percent for rice. Mean WTPs estimated from this study are likely to be overstated due in part to the hypothetical nature of the survey data.biotech foods, ordered probit model, consumer acceptance, willingness to pay, China, Consumer/Household Economics, Research and Development/Tech Change/Emerging Technologies, Q11, Q13,

Consumers' Willingness to Pay for Biotech Foods in China

Based on a large-scale consumer survey, this study employs a semi-double-bounded dichotomous choice model to estimate the mean willingness to pay (WTP) for biotech foods in China. The study also accounts for the effects of respondents' characteristics on the probability of purchasing biotech foods and WTP. Analyses focus on biotech soybean oil and insect-resistant biotech rice.Biotech foods, willingness to pay, China, contingent valuation method, semi-double-bounded dichotomous choice model, Consumer/Household Economics,

Anisotropic power-law inflation for a generalized model of two scalar and two vector fields

Cosmological implication of a generalized model of two scalar and two vector fields, in which both scalar fields are non-minimally coupled to each vector field, is studied in this paper. In particular, we will seek an anisotropic power-law inflationary solution to this model. Furthermore, the stability of the obtained solution will be examined by using the dynamical system approach. As a result, we will show that this solution turns out to be stable and attractive during the inflationary phase as expected due to the existence of the unusual couplings between two scalar and two vector fields. Remarkably, we will point out that the existence of phantom field will lead to an instability of the corresponding anisotropic power-law inflation.Comment: 20 pages, 6 figures. Comments are welcome. arXiv admin note: text overlap with arXiv:2110.1351

Anisotropic power-law inflation for a model of two scalar and two vector fields

Inspired by an interesting counterexample to the cosmic no-hair conjecture found in a supergravity-motivated model recently, we propose a multi-field extension, in which two scalar fields are allowed to non-minimally couple to two vector fields, respectively. This model is shown to admit an exact Bianchi type I power-law solution. Furthermore, stability analysis based on the dynamical system method is performed to show that this anisotropic solution is indeed stable and attractive if both scalar fields are canonical. Nevertheless, if one of the two scalar fields is phantom then the corresponding anisotropic power-law inflation turns unstable as expected.Comment: 13 pages, 2 figures. Updated version, in which several typos are corrected and one reference is added. All results are not changed. Matches the published version. Comments are welcom

Sentiment-oriented metric learning for text-to-image retrieval

National Research Foundation (NRF) Singapore under NRF Fellowship Programm