How geographical neighboring competitors influence the strategic price behaviors of universities is still unclear because previous studies assume spatial independence between universities. Using data from the National Center for Education Statistics college navigator dataset, this study shows that the price of one university is spatially autocorrelated to its neighboring competitors and such neighborhood structure induces cooperation Nash equilibrium in a spatial price game. In the spatial price game of universities the possibility of the cooperation solution is about 76%, while that of the defeat solution is about 24%. This study demonstrates that the relation between price difference and geographical distance of universities is an inverse U-shaped curve rather than a line.
Background: Although coronary heart disease (CHD) is one of the major cardiovascular diseases, risk factors associated with the health-related quality of life (HRQoL) of CHD patients remain unclear. The present study was designed to determine the profile and significant factors of the HRQoL in CHD patients. Methods: A cross-sectional study was conducted in rural communities of Fangshan District, Beijing, China. Socio-demographic, lifestyle, and comorbidity information of CHD patients were collected by a structured questionnaire and medical records. HRQoL was measured using European Quality of Life 5-dimensions (EQ-5D) scale and EQ Visual Analog Scale (EQ-VAS). Multiple linear and logistic regressions were performed to explore the association of potential risk factors with HRQoL scores and each EQ-5D, respectively. Results: Totally, 1928 CHD patients (mean age 61.64 +/- 9.24 years; female:male = 2.4:1) were enrolled in the study. The mean score of EQ-5D index and EQ-VAS were 0.889 +/- 0.172 and 71.56 +/- 17.65, respectively. Multiple linear regression revealed that marital status, physical activity, moderate alcohol drinking, and familys population were positive independent correlates of EQ-VAS, whereas diabetes mellitus and stroke were negative independent correlates (all P < 0.05). Age and stroke were negatively while physical activity, moderate alcohol drinking, familys population and household income were positively correlated with EQ-5D index (all P < 0.05) independently. In addition, each of the five HRQoL dimensions had various specific determinants, including obesity, underweight, smoking or education. Conclusions: Findings of the study highlight certain socio-demographic, lifestyle factors, and comorbid stroke or diabetes mellitus as correlates of HRQoL in Chinese CHD patients. Large-scale cohort studies should be carried out to confirm our results in the future.
BACKGROUND: Although coronary heart disease (CHD) is one of the major cardiovascular diseases, risk factors associated with the health-related quality of life (HRQoL) of CHD patients remain unclear. The present study was designed to determine the profile and significant factors of the HRQoL in CHD patients. METHODS: A cross-sectional study was conducted in rural communities of Fangshan District, Beijing, China. Socio-demographic, lifestyle, and comorbidity information of CHD patients were collected by a structured questionnaire and medical records. HRQoL was measured using European Quality of Life 5-dimensions (EQ-5D) scale and EQ Visual Analog Scale (EQ-VAS). Multiple linear and logistic regressions were performed to explore the association of potential risk factors with HRQoL scores and each EQ-5D, respectively. RESULTS: Totally, 1928 CHD patients (mean age 61.64 +/- 9.24 years; female:male = 2.4:1) were enrolled in the study. The mean score of EQ-5D index and EQ-VAS were 0.889 +/- 0.172 and 71.56 +/- 17.65, respectively. Multiple linear regression revealed that marital status, physical activity, moderate alcohol drinking, and family's population were positive independent correlates of EQ-VAS, whereas diabetes mellitus and stroke were negative independent correlates (all P < 0.05). Age and stroke were negatively while physical activity, moderate alcohol drinking, family's population and household income were positively correlated with EQ-5D index (all P < 0.05) independently. In addition, each of the five HRQoL dimensions had various specific determinants, including obesity, underweight, smoking or education. CONCLUSIONS: Findings of the study highlight certain socio-demographic, lifestyle factors, and comorbid stroke or diabetes mellitus as correlates of HRQoL in Chinese CHD patients. Large-scale cohort studies should be carried out to confirm our results in the future.
BACKGROUND: Although coronary heart disease (CHD) is one of the major cardiovascular diseases, risk factors associated with the health-related quality of life (HRQoL) of CHD patients remain unclear. The present study was designed to determine the profile and significant factors of the HRQoL in CHD patients.
METHODS: A cross-sectional study was conducted in rural communities of Fangshan District, Beijing, China. Socio-demographic, lifestyle, and comorbidity information of CHD patients were collected by a structured questionnaire and medical records. HRQoL was measured using European Quality of Life 5-dimensions (EQ-5D) scale and EQ Visual Analog Scale (EQ-VAS). Multiple linear and logistic regressions were performed to explore the association of potential risk factors with HRQoL scores and each EQ-5D, respectively.
RESULTS: Totally, 1928 CHD patients (mean age 61.64 ± 9.24 years; female:male = 2.4:1) were enrolled in the study. The mean score of EQ-5D index and EQ-VAS were 0.889 ± 0.172 and 71.56 ± 17.65, respectively. Multiple linear regression revealed that marital status, physical activity, moderate alcohol drinking, and family's population were positive independent correlates of EQ-VAS, whereas diabetes mellitus and stroke were negative independent correlates (all P < 0.05). Age and stroke were negatively while physical activity, moderate alcohol drinking, family's population and household income were positively correlated with EQ-5D index (all P < 0.05) independently. In addition, each of the five HRQoL dimensions had various specific determinants, including obesity, underweight, smoking or education.
CONCLUSIONS: Findings of the study highlight certain socio-demographic, lifestyle factors, and comorbid stroke or diabetes mellitus as correlates of HRQoL in Chinese CHD patients. Large-scale cohort studies should be carried out to confirm our results in the future.
Here we compare volatile organic compound (VOC) measurements using a standard proton-transfer-reaction quadrupole mass spectrometer (PTR-QMS) with a new proton-transfer-reaction time of flight mass spectrometer (PTR-TOF) during the Uintah Basin Winter Ozone Study 2013 (UBWOS2013) field experiment in an oil and gas field in the Uintah Basin, Utah. The PTR-QMS uses a quadrupole, which is a mass filter that lets one mass to charge ratio pass at a time, whereas the PTR-TOF uses a time of flight mass spectrometer, which takes full mass spectra with typical 0.1 s-1 min integrated acquisition times. The sensitivity of the PTR-QMS in units of counts per ppbv (parts per billion by volume) is about a factor of 10-35 times larger than the PTR-TOF, when only one VOC is measured. The sensitivity of the PTR-TOF is mass dependent because of the mass discrimination caused by the sampling duty cycle in the orthogonal-acceleration region of the TOF. For example, the PTR-QMS on mass 33 (methanol) is 35 times more sensitive than the PTR-TOF and for masses above 120 amu less than 10 times more. If more than 10-35 compounds are measured with PTR-QMS, the sampling time per ion decreases and the PTR-TOF has higher signals per unit measuring time for most masses. For UBWOS2013 the PTR-QMS measured 34 masses in 37 s and on that timescale the PTR-TOF is more sensitive for all masses. The high mass resolution of the TOF allows for the measurements of compounds that cannot be separately detected with the PTR-QMS, such as oxidation products from alkanes and cycloalkanes emitted by oil and gas extraction. PTR-TOF masses do not have to be preselected, allowing for identification of unanticipated compounds. The measured mixing ratios of the two instruments agreed very well (R-2 >= 0.92 and within 20 %) for all compounds and masses monitored with the PTR-QMS.
For closed quantum systems driven away from equilibrium, work is often defined in terms of projective measurements of initial and final energies. This definition leads to statistical distributions of work that satisfy nonequilibrium work and fluctuation relations. While this two-point measurement definition of quantum work can be justified heuristically by appeal to the first law of thermodynamics, its relationship to the classical definition of work has not been carefully examined. In this paper, we employ semiclassical methods, combined with numerical simulations of a driven quartic oscillator, to study the correspondence between classical and quantal definitions of work in systems with 1 degree of freedom. We find that a semiclassical work distribution, built from classical trajectories that connect the initial and final energies, provides an excellent approximation to the quantum work distribution when the trajectories are assigned suitable phases and are allowed to interfere. Neglecting the interferences between trajectories reduces the distribution to that of the corresponding classical process. Hence, in the semiclassical limit, the quantum work distribution converges to the classical distribution, decorated by a quantum interference pattern. We also derive the form of the quantum work distribution at the boundary between classically allowed and forbidden regions, where this distribution tunnels into the forbidden region. Our results clarify how the correspondence principle applies in the context of quantum and classical work distributions and contribute to the understanding of work and nonequilibrium work relations in the quantum regime.
In addition to surface plasmon polaritons (SPPs), quasi-cylindrical waves (CWs) are also important components of electromagnetic fields on metal surfaces. In this study, we present a closed-form expression for CW fields on a dielectric-film-coated metal surface. It is found that the effective refractive index of CWs roughly keeps unchanged when the coated dielectric film becomes thicker, while the effective refractive index of SPPs increases rapidly. These different responses are explained by referring to a waveguide perspective, in which the SPP and CW waves are, respectively, identified as a waveguide mode and superposition of radiation modes. The results and related analyses with the waveguide perspective explicitly show the different physical natures of SPPs and CWs. (C) 2015 Optical Society of America
Tao S, Fang J, Zhao X, Zhao S, Shen H, Hu H, Tang Z, Wang Z, Guo Q. Rapid loss of lakes on the Mongolian Plateau. Proceedings of the National Academy of SciencesProceedings of the National Academy of Sciences. 2015;112:2281-2286.Abstract
Lakes are widely distributed on the Mongolian Plateau and, as critical water sources, have sustained Mongolian pastures for hundreds of years. However, the plateau has experienced significant lake shrinkage and grassland degradation during the past several decades. To quantify the changes in all of the lakes on the plateau and the associated driving factors, we performed a satellite-based survey using multitemporal Landsat images from the 1970s to 2000s, combined with ground-based censuses. Our results document a rapid loss of lakes on the plateau in the past decades: the number of lakes with a water surface area >1 km2 decreased from 785 in the late 1980s to 577 in 2010, with a greater rate of decrease (34.0%) in Inner Mongolia of China than in Mongolia (17.6%). This decrease has been particularly pronounced since the late 1990s in Inner Mongolia and the number of lakes >10 km2 has declined by 30.0%. The statistical analyses suggested that in Mongolia precipitation was the dominant driver for the lake changes, and in Inner Mongolia coal mining was most important in its grassland area and irrigation was the leading factor in its cultivated area. The deterioration of lakes is expected to continue in the following decades not only because of changing climate but also increasing exploitation of underground mineral and groundwater resources on the plateau. To protect grasslands and the indigenous nomads, effective action is urgently required to save these valuable lakes from further deterioration.