Robust Radio Interferometric Calibration Using the t-Distribution

A major stage of radio interferometric data processing is calibration or the estimation of systematic errors in the data and the correction for such errors. A stochastic error (noise) model is assumed, and in most cases, this underlying model is assumed to be Gaussian. However, outliers in the data due to interference or due to errors in the sky model would have adverse effects on processing based on a Gaussian noise model. Most of the shortcomings of calibration such as the loss in flux or coherence, and the appearance of spurious sources, could be attributed to the deviations of the underlying noise model. In this paper, we propose to improve the robustness of calibration by using a noise model based on Student's t distribution. Student's t noise is a special case of Gaussian noise when the variance is unknown. Unlike Gaussian noise model based calibration, traditional least squares minimization would not directly extend to a case when we have a Student's t noise model. Therefore, we use a variant of the Expectation Maximization (EM) algorithm, called the Expectation-Conditional Maximization Either (ECME) algorithm when we have a Student's t noise model and use the Levenberg-Marquardt algorithm in the maximization step. We give simulation results to show the robustness of the proposed calibration method as opposed to traditional Gaussian noise model based calibration, especially in preserving the flux of weaker sources that are not included in the calibration model.Comment: MNRAS accepte

Design comparison of experimental storm water detention systems treating concentrated road runoff

The aim was to assess the treatment efficiencies of experimental storm water detention (extended storage) systems based on the Atlantis Water Management Limited detention cells receiving concentrated runoff that has been primary treated by filtration with different inert aggregates. Randomly collected gully pot liquor was used in stead of road runoff. To test for a 'worst case scenario', the experimental system received higher volumes and pollutant concentrations in comparison to real detention systems under real (frequently longer but diluted) runoff events. Gravel (6 and 20 mm), sand (1.5 mm), Ecosoil (inert 2 mm aggregate provided by Atlantis Water Management Limited), block paving and turf were tested in terms of their influence on the water quality. Concentrations of five-day @ 20� C ATU biochemical oxygen demand (BOD) in contrast to suspended solids (SS) were frequently reduced to below international secondary wastewater treatment standards. The denitrification process was not completed. This resulted in higher outflow than inflow nitrate-nitrogen concentrations. An analysis of variance indicated that some systems were similar in terms of most of their treatment performance variables including BOD and SS. It follows that there is no advantage in using additional aggregates with high adsorption capacities in the primary treatment stage

Perfect transfer of coherent state-based qubits via coupled cavities

Motivated by the need for communication of coherent state-based qubits in quantum computers, we introduce a method for perfect transferring of an arbitrary superposition of coherent states between two distant nodes of a linear array of three semiconductor QDs. The QDs trapped in a system of coupled cavities. In this method, the field mode of the cavities, as the resource of transferring of quantum states, are only virtually excited which minimizes the effect of decoherence due to photon loss.Comment: 10 pages, 3 figures. arXiv admin note: text overlap with arXiv:quant-ph/0211055 by other author

Perfect routing of quantum information in regular cavity QED networks

We introduce a scheme for perfect routing of quantum states and entanglement in regular cavity QED networks. The couplings between the cavities are quasi-uniform and each cavity is doped with a two-level atom. Quasi-uniform couplings leads the system to evolve in invariant subspaces. Combination the evolutions of the system in its invariant subspaces with quite simple local operations on atoms in the networks, gives the perfect routing of quantum states and entanglement through the network. To provide the protocol be robust due to decoherence arisen from photon loss, the field mode of the cavities are only virtually excited

Music and anxiety in hospitalized children

Purpose: Music is a method of stress reduction and could be used as a non-invasive therapeutic tool to relieve the pain and anxiety of patient. This study is designed to evaluate the role of music therapy on the level of anxiety in children aged 912 yearsold, in an academic hospital in Gorgan, northeast of Iran. Methods: Sixty hospitalized children were categorized into the intervention (case=30) and the control groups (N=30) by using a simple randomized method. The data gathering instruments were questionnaires which included demographic information and a trait anxiety inventory for children, the Spielberger test (STAIC). For the intervention group, for 2 days, 20 minutes (3 am-6 pm), the soothing rhythmic music of Johann Sebastian Bach was released through a tape recorder which was equipped with a headphone and then, the Spielberger questionnaires were refilled by each patient. The control group did not receive any intervention. Results: The results showed that the anxiety scores between the control and the intervention groups had no significant difference before the application of the music. The mean anxiety after the application of music in the control group was 49.4±7.2 and in the intervention group, it was 30.7±7.5. The results showed a significant difference between the mean anxiety in the control and the intervention groups (p<0.05). Conclusions: Our results showed that in hospitalized children, music therapy reduced the anxiety level

Redefinition of the genus Scarabacariphis Masan and new morphological data for S. geotrupes comb. nov. (Ishikawa) (Acari: Mesostigmata: Eviphididae)

International audienceHerein, Alliphis geotrupes Ishikawa, 1979 is transferred to the genus Scarabacariphis Masan, 1994 because of its free peritrematal shield (i.e. separated from the dorsal shield). The genus Scarabacariphis is redefined, and a key to the species of Scarabacariphis is provided, as well as additional morphological information for Scarabacariphis geotrupes comb. nov

The comparison of under-5-year nutritional status among Fars-native, Turkman and Sistani ethnic groups in the north of Iran

Background: Under nutrition is a health problem in developing countries and the main aim of this study was determine of the nutritional status and some sociodemographic factors among rural under-5-year children in the North of Iran in 2013. Methods: This was a descriptive, cross-sectional study, which carried out on 2530 children (637 = Fars-native, 1002 = Turkman and 891 = Sistani) from 21 villages in the North of Iran. Villages were chosen by random sampling among 118, and all of under-five children were chosen by simple sampling. For all of cases, a questionnaire with contain questions on the socialdemographic condition was completed and anthropometric indexes were measured by a learned team. Anthropometric data were compared with those in Centers for Disease Control and Prevention reference population. SPSS 18.0 software was used for statistical data analysis and P value under 0.05 included significations. Results: Generally, under nutrition (Z-score ≤ −2) was observed in 6.6%, 18.5% and 3.3% based on underweight, stunting and wasting, respectively and there were in boys more than girls and in Sistani more than other ethnic groups. Based on underweight and stunting, under nutrition was seen in Sistani more than other ethnic groups. Among three ethnic groups, stunting was significant both in boys (P = 0.013) and in girls (P = 0.004), but wasting was significant only in girls (P = 0.001). The estimated odds ratio (OR) with 95% confidence interval of under nutrition was obtained from logistic regression. Compared with good economic group, the OR was 1.831 in poor economic groups (P = 0.001). The risk of under nutrition in Sistanish ethnic group was 1.754 times more than Fars-native group (P = 0.001). Conclusions: Under nutrition is a health problem among under-5-year children in rural area in the North of Iran and stunting was seen in an alarming rate among them. Among ethnic groups, Sistanish children more than others were under nourished. Poor economic status is a risk factor for under nutrition in this area. © 2015 Veghari G

Teaching Courses in Macroeconomics and Monetary Policy with Bloomberg Analytics

In this article, the authors illustrate the use of Bloomberg for analyzing topics in macroeconomics and monetary policy in economics and finance courses. The hands-on experience that students gain from such a course has many benefits, including deeper learning and clearer understanding of data. The authors describe goals and learning objectives, then compare Bloomberg with Federal Reserve Economic Data (FRED). In addition, they provide examples of how to use Bloomberg in the classroom, describe how to have students perform sector analysis, show how Bloomberg tools are useful for analyzing monetary policy, discuss how to use Bloomberg to analyze the financial sector, and illustrate the platform’s use in a case study