An Empirical Relation Between The Large-Scale Magnetic Field And The Dynamical Mass In Galaxies

The origin and evolution of cosmic magnetic fields as well as the influence of the magnetic fields on the evolution of galaxies are unknown. Though not without challenges, the dynamo theory can explain the large-scale coherent magnetic fields which govern galaxies, but observational evidence for the theory is so far very scarce. Putting together the available data of non-interacting, non-cluster galaxies with known large-scale magnetic fields, we find a tight correlation between the integrated polarized flux density, S(PI), and the rotation speed, v(rot), of galaxies. This leads to an almost linear correlation between the large-scale magnetic field B and v(rot), assuming that the number of cosmic ray electrons is proportional to the star formation rate, and a super-linear correlation assuming equipartition between magnetic fields and cosmic rays. This correlation cannot be attributed to an active linear alpha-Omega dynamo, as no correlation holds with global shear or angular speed. It indicates instead a coupling between the large-scale magnetic field and the dynamical mass of the galaxies, B ~ M^(0.25-0.4). Hence, faster rotating and/or more massive galaxies have stronger large-scale magnetic fields. The observed B-v(rot) correlation shows that the anisotropic turbulent magnetic field dominates B in fast rotating galaxies as the turbulent magnetic field, coupled with gas, is enhanced and ordered due to the strong gas compression and/or local shear in these systems. This study supports an stationary condition for the large-scale magnetic field as long as the dynamical mass of galaxies is constant.Comment: 23 pages, 4 figures, accepted for publication in the Astrophysical Journal Letter

The role of thermal and non-thermal processes in the ISM of the Magellanic Clouds

Radio continuum emission is a dust-unbiased tracer of both thermal and non-thermal processes in the interstellar medium. We present new maps of the free–free and synchrotron emission in the Magellanic Clouds (MCs) at 0.166, 1.4, and 4.8 GHz with no prior assumption about the radio non-thermal spectrum. The maps were constructed using a de-reddened H α map as a template for the thermal radio emission, which we subtract from maps of the total radio continuum emission. To de-redden the H α emission, it is important to know the fraction of dust surface density that attenuates the H α emission along the line of sight, fd. This fraction is obtained by comparing the dust opacity obtained through the infrared emission spectrum and the Balmer decrement method. In star-forming regions, the median fd is about 0.1, which is lower than that in diffuse regions by a factor of three. We obtain a global thermal radio fraction, fth, of 30 per cent (35 per cent) in the LMC (SMC) at 1.4 GHz. Furthermore, we present maps of the equipartition magnetic field strength with average values of ≃10.1μG in the LMC and ≃5.5μG in the SMC. The magnetic field is proportional to the star-formation rate to the power of 0.24 and 0.20 for the LMC and SMC, respectively. This study shows that non-thermal processes control the interstellar medium in the MCs

Repelling Random Walkers in a Diffusion-Coalescence System

We have shown that the steady state probability distribution function of a diffusion-coalescence system on a one-dimensional lattice of length L with reflecting boundaries can be written in terms of a superposition of double shock structures which perform biased random walks on the lattice while repelling each other. The shocks can enter into the system and leave it from the boundaries. Depending on the microscopic reaction rates, the system is known to have two different phases. We have found that the mean distance between the shock positions is of order L in one phase while it is of order 1 in the other phase.Comment: 5 pages, 1 EPS figure, Accepted for publication in PRE (2008

Blackfly fever and dermatitis caused by Simulium kiritshenkoi: a human case report in Iran

BACKGROUND: Besides the considerable role of blackflies to the transmission of many disease agents, these flies considered as annoying biting pests of wildlife, livestock, poultry, and humans. There are few literature reports of blackfly fever following Simulium spp. This study describes a case of blackfly fever and dermatitis following blackflies numerous bites in Iran. CASE PRESENTATION: The present report describes a 25-year-old man that was attacked by numerous flies while fishing and camping near Namrood river in Firuzkuh County, Tehran Province, Iran. Pruritic dermatitis with marked edema appeared mainly on the hands and legs and subsequently, the patient's condition worsened with swollen lymph nodes, joints aching, and 40�°C fever. The patient's clinical signs and symptoms were alleviated by injection of intramuscular Dexamethasone Phosphate (DEXADIC®) 8�mg/2�ml after 24�h. CONCLUSIONS: This study reported a human case with blackfly fever and dermatitis following numerous bites of Simulium kiritshenkoi, for the first time in Iran

Dietary intake and lifestyle behavior in different phenotypes of polycystic ovarian syndrome: a case-control study

Objective: To compare dietary intake and lifestyle behaviour in women with polycystic ovarian syndrome (PCOS) and healthy women. Methods: 160 healthy women (partner with male infertility) were recruited to a control group; 168 women with PCOS (diagnosed on ultrasound) were recruited to a case study group for this cross-sectional comparative study. The case group was classified into three phenotypes based on presence or absence of menstrual disorder (M), hyperandrogenism (HA), and polycystic ovary according to sonography (PCO): HA+PCO (n=53), PCO+M (n=57) and M+HA+PCO (n=66). Dietary intake and lifestyle behaviour were measured using a food frequency questionnaire (FFQ) and a lifestyle questionnaire (LQ). Results: The mean energy (P<0.001) and fat intake (P<0.001) were greater in PCOS groups compared with the control group. The average energy and fat intake were greater in HA+M+PCO group after age and BMI adjustment compared with other phenotypes (P<0.001). In comparison with the control group, lifestyle scores were lower in the PCOS group in the fields of physical activity, weight and nutrition control after age and BMI adjustment (P<0.001). The average score of lifestyle in the fields of physical activity, weight and nutrition control, and psychological health was lower in the phenotype HA+M+PCO compared with other phenotypes (P<0.001). Conclusions: Limited energy and fat intake is strongly recommended in Iranian women with PCOS especially in phenotype HA+M+PCO. Consultation on improvement of psychological health and the importance of weight and nutrition control, and appropriate physical activity in patients especially in HA+M+PCO is advocated. Keywords: Lifestyle, polycystic ovarian syndrome, die

Research Article Presenting a Framework for Ranking Identification System in the Chain Store: Real Case Study of the Iran SHAHRVAND Department Store

Abstract: The purpose of this research is to specify and rank the appropriate automatic identifying goods system for a real case of a department store (Shahrvand department store). The ideas of the experts about the most appropriate identifying goods system in the department store are evaluated and collected by the brainstorming method, the three types of identification system which are specified by the brainstorming method are: RFID (Radio Frequency IDentification), Barcode and OCR (Optical Character Recognition). In order to ranking the achieved automatic identification systems and helping the management of the department store for decision making, the promethee (Preference Ranking Organization Method for Enrichment Evaluations) method is selected which has the most conformity with this research between the all MCDM (Multi Criteria Decision Making) method. Therefore, by consideration of two approaches: &quot;efficiency of identification systems&quot; and &quot;convenience of customer purchase&quot; eight criteria are extracted for ranking the identification system. Finally, the RFID system is preferred to other automatic identifying good systems by the used method in the research

Fermat-linked relations for the Boubaker polynomial sequences via Riordan matrices analysis

The Boubaker polynomials are investigated in this paper. Using Riordan matrices analysis, a sequence of relations outlining the relations with Chebyshev and Fermat polynomials have been obtained. The obtained expressions are a meaningful supply to recent applied physics studies using the Boubaker polynomials expansion scheme (BPES).Comment: 12 pages, LaTe

A Detailed Study of the Radio--FIR Correlation in NGC6946 with Herschel-PACS/SPIRE from KINGFISH

We derive the distribution of the synchrotron spectral index across NGC6946 and investigate the correlation between the radio continuum (synchrotron) and far-infrared (FIR) emission using the KINGFISH Herschel PACS and SPIRE data. The radio--FIR correlation is studied as a function of star formation rate, magnetic field strength, radiation field strength, and the total gas surface brightness. The synchrotron emission follows both star-forming regions and the so-called magnetic arms present in the inter-arm regions. The synchrotron spectral index is steepest along the magnetic arms ($\alpha_n \sim 1$), while it is flat in places of giant H{\sc ii} regions and in the center of the galaxy ($\alpha_n \sim 0.6-0.7$). The map of $\alpha_n$ provides an observational evidence for aging and energy loss of cosmic ray electrons propagating in the disk of the galaxy. Variations in the synchrotron--FIR correlation across the galaxy are shown to be a function of both star formation and magnetic fields. We find that the synchrotron emission correlates better with cold rather than with warm dust emission, when the interstellar radiation field is the main heating source of dust. The synchrotron--FIR correlation suggests a coupling between the magnetic field and the gas density. NGC6946 shows a power-law behavior between the total (turbulent) magnetic field strength B and the star formation rate surface density $\Sigma_{\rm SFR}$ with an index of 0.14\,(0.16)$\pm$0.01. This indicates an efficient production of the turbulent magnetic field with the increasing gas turbulence expected in actively star forming regions. The scale-by-scale analysis of the synchrotron--FIR correlation indicates that the ISM affects the propagation of old/diffused cosmic ray electrons, resulting in a diffusion coefficient of $D_0=4.6\times 10^{28}$\,cm$^2$\,s$^{-1}$ for 2.2\,GeV CREs.Comment: 23 pages, 13 figures, accepted for publication in Astronomy & Astrophysics Journa