We study the simplest optomechanical system with a focus on the bistable regime. The covariance matrix formalism allows us to study both cooling and entanglement in a unified framework. We identify two key factors governing entanglement; namely, the bistability parameter (i.e., the distance from the end of a stable branch in the bistable regime) and the effective detuning, and we describe the optimum regime where entanglement is greatest. We also show that, in general, entanglement is a nonmonotonic function of optomechanical coupling. This is especially important in understanding the optomechanical entanglement of the second stable branch.

Some studies have suggested that the number of deaths increases as temperatures drops or rises above human thermal comfort zone. The present study was conducted to evaluate the relation between respiratory-related mortality and temperature in Shiraz, Iran. In this ecological study, data about the number of respiratory-related deaths sorted according to age and gender as well as average, minimum, and maximum ambient air temperatures during 2007-2011 were examined. The relationship between air temperature and respiratory-related deaths was calculated by crude and adjusted negative binomial regression analysis. It was adjusted for humidity, rainfall, wind speed and direction, and air pollutants including CO, NO, PM, SO, O, and THC. Spearman and Pearson correlations were also calculated between air temperature and respiratory-related deaths. The analysis was done using MINITAB16 and STATA 11. During this period, 2598 respiratory-related deaths occurred in Shiraz. The minimum number of respiratory-related deaths among all subjects happened in an average temperature of 25 °C. There was a significant inverse relationship between average temperature- and respiratory-related deaths among all subjects and women. There was also a significant inverse relationship between average temperature and respiratory-related deaths among all subjects, men and women in the next month. The results suggest that cold temperatures can increase the number of respiratory-related deaths and therefore policies to reduce mortality in cold weather, especially in patients with respiratory diseases should be implemented.

BackgroundSome epidemiological evidence has shown a relation between ambient air pollution and adverse health outcomes. The aim of this study was to investigate the effect of air pollution on mortality from respiratory diseases in Tehran, Iran.MethodsIn this ecological study, air pollution data was inquired from the Tehran Province Environmental Protection Agency and the Tehran Air Quality Control Company. Meteorological data was collected from the Tehran Meteorology Organization and mortality data from the Tehran Cemetery Mortality Registration. Generalized Additive Models (GAM) was used for data analysis with different lags, up to 15 days. A 10-unit increase in all pollutants except CO (1-unit) was used to compute the Relative Risk of deaths.ResultsDuring 2005 until 2014, 37,967 respiratory deaths occurred in Tehran in which 21,913 (57.7%) were male. The strongest relationship between NO2 and PM10and respiratory death was seen on the same day (lag 0), and was respectively (RR = 1.04, 95% CI: 1.02–1.07) and (RR = 1.03, 95% CI: 1.02–1.04). O3 and PM2.5 had the strongest relationship with respiratory deaths on lag 2 and 1 respectively, and the RR was equal to 1.03, 95% CI: 1.01–1.05 and 1.06, 95% CI: 1.02–1.10 respectively. NO2, O3, PM10 and PM2.5 also showed significant relations with respiratory deaths in the older age groups.ConclusionsThe findings of this study showed that O3, NO2, PM10 and PM2.5 air pollutants were related to respiratory deaths in Tehran. Reducing ambient air pollution can save lives in Tehran.

We analyze the impact of loss in lattices of coupled optical waveguides and find that in such case, the hopping between adjacent waveguides is necessarily complex. This results not only in a transition of the light spreading from ballistic to diffusive, but also in a new kind of diffraction that is caused by loss dispersion. We prove our theoretical results with experimental observations. PACS numbers: PACS numbers: 42.25. Bs, 42.79.Gn, 72.10.Bg, 73.23.Ad Absorption is an intrinsic feature of photonic systems, arising due to the laws of causality [1]. It results in decoherence and, hence, in a considerable change in the dynamics of optical waves. However, it is generally agreed that in the particular case of homogeneous and isotropic loss the impact on the amplitude distribution in the system vanishes, besides a global decay of the integrated power [1]. A very prominent photonic system is arrays of evanescently coupled waveguides [2], where a tailored absorption (or absorption/gain) distribution is the basis for a multitude of unexpected physical phenomena, such as exceptional points [3], unusual beam dynamics [4], spontaneous PT -symmetry breaking [5], non-reciprocal Bloch oscillations [6] and dynamic localization [7], unidirectional cloaking [8], and even tachyonic transport [9]. Owing to the intuition described above, if all lattice sites exhibit exactly the same absorption, its impact vanishes in the evolution equations of these systems. In a more mathematical language, in this case absorption adds to the Hamiltonian as a pure diagonal matrix with identical elements, which can be removed by normalization.In our work we show that absorption in coupled waveguide systems does always impact the light dynamics, even if it is homogeneous and isotropic in all lattice sites. Due to the imaginary part of the dielectric function (that describes the absorption) imaginary off-diagonal elements in the Hamiltonian appear that cannot be removed by normalization, causing significant deviations in the light dynamics compared to the Hermitian case. However, our theory holds for all Schrödinger type systems that can be mapped onto a tight binding lattice, e.g., paraxial waves in optics or mechanics as well as quantum dynamics in spin chains, population transfer in multi-level systems and graphene. Our theory supplements the knowledge about the influence of non-Hermiticity to all these systems in general including the effect of PT symmetry.In order to study the impact of absorption in such systems, we consider a one-dimensional array of N identical single mode optical waveguides with width 2w, inter-site spacing d, and the complex relative electric permittivity + i at the positions x n (n = 1, 2, ..., N ), which is surrounded by a bulk material (with 0 + i 0 ). A sketch of this system is shown in Fig. 1.The dynamics of wave propagating through this system is governed by the Helmholtz wave equationwhere ψ(x, z) is the electric field amplitude, k 0 = ω c is the propagation constant in free space, and ε(x) is relative electric ...

Many studies have suggested that cardiovascular and respiratory disease mortality may change with fluctuations in temperature. In this study the relation between temperature and mortality has been studied in a city with desert climate. Four years data on daily temperature, cardiovascular, respiratory mortality and air pollution was acquired for Kerman, Iran. Time series, regression and correlation analyses were performed. Results showed an inverse relationship between mortality and temperature in Kerman, in which decreases in temperature were associated with increases in mortality. This pattern is similar to some foreign studies which show acclimatization of people living in southern warmer climates and less negative effects of warm temperatures. Among the pollutants only dust (p=0.003) and SO2 (p<0.001) showed a positive correlation with respiratory mortality.