Nonequilibrium field-induced phase separation in single-file diffusion

Using an analytically tractable lattice model for reaction-diffusion processes of hard-core particles we demonstrate that under nonequilibrium conditions phase coexistence may arise even if the system is effectively one-dimensional as e.g. in the channel system of some zeolites or in artificial optical lattices. In our model involving two species of particles a steady-state particle current is maintained by a density gradient between the channel boundaries and by the influence of an external driving force. This leads to the development of a fluctuating but always microscopically sharp interface between two domains of different densities which are fixed by the boundary chemical potentials. The internal structure of the interface becomes very simple for strong driving force. We calculate the drift velocity and diffusion coefficient of the interface in terms of the microscopic model parameters.Comment: 38 pages, 2 figure

Thermal and Nonthermal Emission from the Nearby Galaxy M33 : A Multi-Scale Study of Infrared and Radio Emission

A multi-wavelength study of radio and IR emission from the nearby galaxy M33 is presented. We focus on three main topics: 1) energy sources of IR emission and its correlation with radio continuum emission at different spatial scales, 2) separation of thermal and nonthermal components of the radio continuum emission without assuming a constant nonthermal spectral index, and 3) distribution of the linearly polarized emission and magnetic fields in M33. Highly resolved and sensitive Spitzer MIPS images of M33 at 24, 70, and 160μm enabled us to study the morphology of different dust components and their role in attenuation of the Hα emission from this galaxy. Radio continuum observations with the VLA and the 100-m Effelsberg telescope led to high sensitive maps of total and linearly polarized radio continuum emission at low (1.42 GHz) and high frequencies (8.35 GHz). A 2D-wavelet transformation was used to find dominant scales of emitting structures, separate the diffuse emission components from compact sources, and compare IR emitting structures to those at radio and Hα wavelengths. We found that the IR emission is powered predominantly by young O/B stars, specifically at 24μm and 70μm. At least up to scales of 0.8 kpc, the cold dust (emitting at 160µm) is also effectively heated by UV photons from massive ionizing stars, however, the average radiation field also contributes to heating the cold dust at larger scales. At scales smaller than 4 kpc, emission from both the warm and the cold dust show better correlation with the thermal radio than with the nonthermal radio emission, indicating a more important role of UV photons from O/B stars than of cosmic ray electrons in heating the dust at these scales. Interestingly, there is a characteristic scale range where the nonthermal radio-IR correlation is maximum: scales of giant star-forming regions, spiral arms and the central extended region of M33, 0.8-2 kpc, indicating regions with high-density cosmic rays and/or stronger (turbulent) magnetic field. We developed a new thermal/nonthermal separation method based on a de-reddened Hα map as a template for the thermal radio emission. For the first time, we derived a map of the nonthermal spectral index in a galaxy by means of this method, directly indicating energy loss of cosmic ray electrons when diffusing away from their origins in star-forming regions towards interarm regions and the outer parts of the galaxy. Furthermore, this energy loss is more significant at 8.35 GHz than at 1.42 GHz. Assuming equipartition between the magnetic field and cosmic ray electrons, we obtained the scale length of the cosmic ray electrons and of the magnetic field of about 12 kpc and 24 kpc, respectively. The large-scale magnetic field exhibits a well ordered spiral structure with almost the same orientation as that of the optical spiral arms. There is a north-south asymmetry in the received polarized emission that is frequency-dependent and most probably caused by Faraday depolarization effects. About 10% of the nonthermal emission from M33 at 8.35 GHz is polarized, mostly due to the strong polarized emission from a magnetic arm in the north-west of the galaxy. The average total and regular magnetic field strengths in M33 are about 6.4μG and 2.5μG, respectively

Radio emission during the formation of stellar clusters in M33

We investigate thermal and non-thermal radio continuum associated with the early formation and evolution of Young Stellar Clusters (YSCs) selected by their MIR emission in M33. For the first time in an external galaxy it has been possible to identify radio counterparts to more than 300 star forming regions. We proof the nature of candidate YSCs fully embedded in molecular clouds, by recovering their associated faint radio continuum luminosities. Using the Halpha line to identify free-free radio emission at 5 GHz in the more evolved, partially exposed YSCs, we retrieve information on the relevance of magnetic fields and cosmic rays across the M33 disk at 25 pc spatial scales. A cross-correlation of MIR and radio continuum luminosities is established from bright to very faint YSCs, with MIR-to-radio emission ratio showing a gradual decline towards the outer disk, while the magnetic field is pervasive at all radii. We establish and discuss the tight relation between radio continuum and other star formation indicators, such as Halpha. This relation holds for individual YSCs over four orders of magnitude as well as for molecular clouds hosting YSCs. On average about half of radio emission at 5 GHz in YSCs is non-thermal. For exposed but compact YSCs the non-thermal radio fraction increases with source brightness, while for large HII regions the fraction is lower and shows no clear trend. This has been found for YSCs with and without identified SNRs and underlines the possible role of massive stars in triggering particle acceleration through winds and shocks: these particles diffuse throughout the native molecular cloud prior to cloud dispersal.Comment: 14 pages, 10 figures, accepted for publication in A&

Lack of Interaction between the Dust Grains and the Anomalous Radio Jet in the Nearby Spiral Galaxy NGC 4258

We obtained Spitzer/IRAC 3.6-8 micron images of the nearby spiral galaxy NGC 4258 to study possible interactions between dust and the radio jet. In our analysis we also included high-resolution radio continuum, H-alpha, CO, and X-ray data. Our data reveal that the 8 micron emission, believed to originate largely from PAH molecules and hot dust, is an excellent tracer of the normal spiral structure in NGC 4258, and hence it originates from the galactic plane. We investigated the possibility of dust destruction by the radio jet by calculating correlation coefficients between the 8 micron and radio continuum emissions along the jet in two independent ways, namely (i) from wavelet-transformed maps of the original images at different spatial scales, and (ii) from one-dimensional intensity cuts perpendicular to the projected path of the radio jet on the sky. No definitive sign of a correlation (or anticorrelation) was detected on relevant spatial scales with either approach, implying that any dust destruction must take place at spatial scales that are not resolved by our observations.Comment: Accepted for publication in the Astronomical Journal (11 pages, 10 figures, 1 table

The Resolved Radio--FIR Correlation in Nearby Galaxies with Herschel and Spitzer

We investigate the correlation between the far-infrared (FIR) and radio continuum emission from NGC6946 on spatial scales between 0.9 and 17 kpc. We use the Herschel PACS (70, 100, 160$\mu$m) and SPIRE (250$\mu$m) data from the KINGFISH project. Separating the free-free and synchrotron components of the radio continuum emission, we find that FIR is better correlated with the free-free than the synchrotron emission. Compared to a similar study in M33 and M31, we find that the scale dependence of the synchrotron--FIR correlation in NGC6946 is more similar to M31 than M33. The scale dependence of the synchrotron--FIR correlation can be explained by the turbulent-to-ordered magnetic field ratio or, equivalently, the diffusion length of the cosmic ray electrons in these galaxies.Comment: 4 pages, 3 figures, The Spectral Energy Distribution of Galaxies Proceedings IAU Symposium No. 284, 2011, R.J. Tuffs & C.C.Popescu, ed

Shocks in the asymmetric exclusion process with internal degree of freedom

We determine all families of Markovian three-states lattice gases with pair interaction and a single local conservation law. One such family of models is an asymmetric exclusion process where particles exist in two different nonconserved states. We derive conditions on the transition rates between the two states such that the shock has a particularly simple structure with minimal intrinsic shock width and random walk dynamics. We calculate the drift velocity and diffusion coefficient of the shock.Comment: 26 pages, 1 figur

Attitude and readiness of Dentistry students in Kerman University of Medical Sciences concerning Tele-dentistry in 2017

Introduction: Tele-dentistry is the use of information and telecommunications technology for dental care, counseling, education and public awareness in the same way as remote medical. Tele-dentistry is a relatively new field that can change the dental care system. However, many dentists are unaware of the goals, benefits, and how to participate. Therefore, this study was conducted to determine the knowledge and attitude of dental students regarding telemedicine. Methods:The present study is descriptive-analytic. The study population consisted of all dental students in Kerman in year 2017 and sample of 230 students selected by proportional sampling. For data collection, a complete English translation of an English-language article in the Journal of Clinical and Diagnostic Research, whose validity was confirmed by three of the leading medical informatics specialists in English, was then used to analyze the data using the software SPSS 19. Results: The findings of this study showed that there is no significant difference between the students' age, sex and term of education with their knowledge of tele-dentistry (P>0.05). Knowledge and attitude of 72% of students in tele-dentistry is very low. 40% of them said tele-dentistry would be very beneficial and more than half of them would be willing to do tele-dentistry in the future. 81% of them agreed that tele-dentistry could be a good tool for health education and oral health, and effective in educating the health of a large number of people. 75% of them felt that distance dental care saves time, and 81% of students believed that tele-dentistry was not financially feasible. Conclusion: The results of this study showed that many respondents lacked adequate knowledge and knowledge about tele-dentistry. Hence, there is a huge need for awareness among dentists to further the future of dentistry in the future. Therefore, it is suggested that the related institutions take more serious measures for awareness and education about tele-dentistry for students

Cranial phenotypic variation in Meriones crassus and M. libycus (Rodentia, Gerbillinae), and a morphological divergence in M. crassus from the Iranian Plateau and Mesopotamia (Western Zagros Mountains)

Jirds (genus Meriones) are a diverse group of rodents, with a wide distribution range in Iran. Sundevall’s jird (Meriones crassus Sundevall, 1842) is one such species that shows a disjunct distribution, found on the Iranian Plateau and Western Zagros Mountains. Morphological differences observed between these two populations, however, lack quantitative support. Morphological differences between geographical populations of Meriones crassus were analysed and compared with those of the sympatric M. libycus. Similarities in the cranial morphology of these species were found, e.g. in a relatively large and inflated bulla. A two-dimensional geometric morphometric analysis was done on the skull of 275 M. crassus and 220 M. libycus from more than 70 different localities in their distribution range. Results confirm cranial differences between specimens of M. crassus from the Western Zagros and those from Africa and Arabia, mainly at the level of the relative size of the tympanic bulla, that were significantly correlated with the annual rainfall and elevation. Moreover, the study supports the hypothesis that the Western Zagros specimens are both a geographically and phenotypically distinct group compared to the other Iranian M. crassus specimens, suggesting that the former might be a distinct species

Morphological plasticity of Nemoura Cinerea (Arthropoda, Nemouridae) as a biological indicator for aquatic systems

Macrobenthos are indicators of the physical and chemical changes in aquatic ecosystems. In this research, the diversity of macrobenthos communities in the Ortkand River, Iran, was investigated during four consecutive seasons using the Shannon-Weiner, EPT richness indices, and the Hilsenhoff index for water quality at four sampling stations. In addition, sampling of Nemoura cinerea (Arthropoda, Nemouridae) was done to compare morphological differences between specimens from two upstream and downstream sites using a geometric morphometric approach. The physicochemical parameters of water were also recorded. The entry of fish farm wastewater significantly affects biotic and abiotic environmental factors according to the Shannon-Weiner and Hilsenhoff indices. The results showed a significant positive correlation between DO and Shannon-Wiener index, TDS and the Hilsenhoff index, and DO and EPT richness index. A significant negative correlation was observed between BOD and the Shannon-Wiener index, DO and Hilsenhoff index, and between BOD and EPT richness index. Geometric morphometrics analyses revealed that the two groups differed mainly in pronotum and metanotum morphology. According to the results, monitoring of macrobenthos can help assess rivers’ water quality, and N. cinerea can be a proper bioindicator