The radio-infrared correlation in galaxies

The radio-infrared correlation was explained as a direct and linear relationship between star formation and IR emission. However, one fact making the IR-star formation linkage less obvious is that the IR emission consists of at least two emission components, cold dust and warm dust. The cold dust emission may not be directly linked to the young stellar population. Furthermore, understanding the origin of the radio-IR correlation requires to discriminate between the two main components of the radio continuum emission, free-free and synchrotron emission. Here, we present a multi-scale study of the correlation of IR with both the thermal and non-thermal (synchrotron) components of the radio continuum emission from the nearby galaxies M33 and M31.Comment: To appear in Highlights of Astronomy, Volume 15, XXVIIth IAU General Assembly, August 200

The Local Radio-IR Relation in M51

We observed M51 at three frequencies, 1.4 GHz (20 cm), 4.9 GHz (6 cm), and 8.4 GHz (3.6 cm), with the Very Large Array and the Effelsberg 100 m telescope to obtain the highest quality radio continuum images of a nearby spiral galaxy. These radio data were combined with deconvolved Spitzer IRAC 8 μm and MIPS 24 μm images to search for and investigate local changes in the radio-IR correlation. Utilizing wavelet decomposition, we compare the distribution of the radio and IR emission on spatial scales between 200 pc and 30 kpc. We show that the radio-IR correlation is not uniform across the galactic disk. It presents a complex behavior with local extrema corresponding to various galactic structures, such as complexes of H II regions, spiral arms, and interarm filaments, indicating that the contribution of the thermal and non-thermal radio emission is a strong function of environment. In particular, the relation of the 24 μm and 20 cm emission presents a linear relation within the spiral arms and globally over the galaxy, while it deviates from linearity in the interarm and outer regions as well in the inner region, with two different behaviors: it is sublinear in the interarm and outer region and overlinear in the central 3.5 kpc. Our analysis suggests that the changes in the radio/IR correlation reflect variations of interstellar medium properties between spiral arms and interarm region. The good correlation in the spiral arms implies that 24 μm and 20 cm are tracing recent star formation, while a change in the dust opacity, "Cirrus" contribution to the IR emission and/or the relation between the magnetic field strength and the gas density can explain the different relations found in the interarm, outer, and inner regions

Investigating the Effect of Zinc Chloride to Control External Bleeding in Rats

Background: Despite all progresses in surgical science, bleeding caused by traffic accidents is still a challenge for surgeons to save patients’ lives. Therefore, introducing an effective method to control external bleeding is an important research priority. Objectives: This study aimed to compare haemostatic effect of zinc chloride and simple suturing to control external bleeding. Materials and Methods: In this animal model study, 60 male Wistar rats were used. An incision (two cm in length and half a cm in depth) was made on shaved back of rats. The hemostasis time was measured once using zinc chloride with different concentrations (5%, 10%, 15%, 25%, and 50%) and then using simple suturing. Skin tissue was assessed for pathological changes. Due to abnormal distribution of variables in Kolmogorov-Smirnov test, the data was analyzed using Kruskal-Wallis test Mann-Whitney U tests. Results: In all the groups, complete hemostasis occurred. Hemostasis times of different concentrations of zinc chloride were significantly less than that of the control group (P < 0.001). Conclusions: Zinc chloride was effective to control external bleeding in rats

Integrated Treatment of Saline Oily Wastewater Using Sono-Electrokinetic Process, Degradation Mechanism, and Toxicity Assessment

Integration of sonication (US) with electrokinetic (EK) oxidation was studied for the treatment of a saline oily wastewater, as well as the effect of operating parameters, including pH, voltage, electrode distance (ED), sonication power, and reaction time on COD removal. A COD removal of 98 % was observed for the sono-electrokinetic (SEK) process with an applied voltage of 2.5 V, US power of 300 W, initial COD concentration of 3850 mg L–1, and reaction time of 9 h. The efficiency of SEK over sonication alone and EK oxidation alone was also confirmed with a higher pseudo-first-order reaction rate constant of 0.43 h–1, compared to values of 0.13 and 0.01 for alternative processes. In addition, the biodegradability of effluent was improved based on average oxidation state (AOS) and carbon oxidation state (COS) analysis. Oxygen consumption rate inhibition, dehydrogenase activity inhibition, and growth rate inhibition methods demonstrated the low toxicity of effluent (12–15 %) compared to influent. The current work indicated that SEK is a reliable and efficient technology for the treatment of saline oily wastewaters containing recalcitrant aromatic organics. This work is licensed under a Creative Commons Attribution 4.0 International License

The Magnetized Disk-Halo Transition Region of M51

An excellent laboratory for studying large scale magnetic fields is the grand de- sign face-on spiral galaxy M51. Due to wavelength-dependent Faraday depolarization, linearly polarized synchrotron emission at different radio frequencies gives a picture of the galaxy at different depths: Observations at L-band (1-2 GHz) probe the halo region while at C- and X- band (4-8 GHz) the linearly polarized emission probe the disk region of M51. We present new observations of M51 using the Karl G. Jansky Very Large Array (VLA) at S-band (2-4 GHz), where previously no polarization observations existed, to shed new light on the transition region between the disk and the halo. We discuss a model of the depolarization of synchrotron radiation in a multilayer magneto-ionic medium and compare the model predictions to the multi-frequency polarization data of M51 between 1-8GHz. The new S-band data are essential to distinguish between different models. Our study shows that the initial model parameters, i.e. the total reg- ular and turbulent magnetic field strengths in the disk and halo of M51, need to be adjusted to successfully fit the models to the data.Comment: 4 Pages, 3 Figures, Conference Proceeding to IAU Focus Meeting 8: New Insights in Extragalactic Magnetic Field