Interperiod coherent integration of the received signal with a variable repetition period of the probing signal

Interperiod coherent integration of the received signal provides an increase in the signal-to-noise ratio and is simply implemented with a fixed repetition period of the probing signals. In practice, pulsed radars use a variable repetition period to protect against blind speeds. The algorithms of the interperiod coherent integration with a variable repetition period have been developed and their features have been revealed, which are advisable to take into account in the practical implementation in the radars. These features determine the complexity of the interperiod coherent integration algorithm, the radial velocity (Doppler frequency) survey interval and the spectrum features. An algorithm is developed with simultaneous interperiod coherent integration of the received signal and a single-delay clutter cancelation in the spectral domain in the case of variable repetition period of the probing signals. The quantitative indicators obtained by modeling are presented and a comparative analysis is carried out.

Remnant radio galaxies discovered in a multi-frequency survey

The remnant phase of a radio galaxy begins when the jets launched from an active galactic nucleus are switched off. To study the fraction of radio galaxies in a remnant phase, we take advantage of a $8.31$ deg $^2$ subregion of the GAMA 23 field which comprises of surveys covering the frequency range 0.1–9 GHz. We present a sample of 104 radio galaxies compiled from observations conducted by the Murchison Widefield Array (216 MHz), the Australia Square Kilometer Array Pathfinder (887 MHz), and the Australia Telescope Compact Array (5.5 GHz). We adopt an ‘absent radio core’ criterion to identify 10 radio galaxies showing no evidence for an active nucleus. We classify these as new candidate remnant radio galaxies. Seven of these objects still display compact emitting regions within the lobes at 5.5 GHz; at this frequency the emission is short-lived, implying a recent jet switch off. On the other hand, only three show evidence of aged lobe plasma by the presence of an ultra-steep-spectrum ( $\alpha<-1.2$ ) and a diffuse, low surface brightness radio morphology. The predominant fraction of young remnants is consistent with a rapid fading during the remnant phase. Within our sample of radio galaxies, our observations constrain the remnant fraction to $4\%\lesssim f_{\mathrm{rem}} \lesssim 10\%$ ; the lower limit comes from the limiting case in which all remnant candidates with hotspots are simply active radio galaxies with faint, undetected radio cores. Finally, we model the synchrotron spectrum arising from a hotspot to show they can persist for 5–10 Myr at 5.5 GHz after the jets switch of—radio emission arising from such hotspots can therefore be expected in an appreciable fraction of genuine remnants.

Call Me Maybe: Experimental Evidence on Frequency and Medium Effects in Microenterprise Surveys

This study analyzes the effects of differences in survey frequency and medium on microenterprise survey data. A sample of enterprises were randomly assigned to monthly in-person, weekly in-person, or weekly phone surveys for a 12-week panel. The results show few differences across the groups in measured means, distributions, and deviations of measured data from an objective data-quality standard provided by Benford’s Law. However, phone interviews generated higher within-enterprise variation through time in several variables and may be more sensitive to social desirability bias. Higher-frequency interviews did not lead to persistent changes in reporting or increase permanent attrition from the panel but did increase the share of missed interviews. These findings show that collecting high-frequency survey data by phone does not substantially affect data quality. However, researchers who are particularly interested in within-enterprise dynamics should exercise caution when choosing survey medium.

Effectiveness and applicability of low FODMAP diet in the irritable bowel syndrome: Preliminary results of a prospective study

Introduction: Irritable bowel syndrome (IBS) is a very common entity that alters patient’s life quality worldwide. Several therapeutic modalities are available with variable results. Recently, the low-FODMAP diet effect on IBS symptoms has been proven. The aim of our study was to study the efficiency of this diet and to assess its applicability in a Tunisian IBS group of patients. Methods: A longitudinal, prospective study including 34 patients with IBS was conducted. Patients responded to a food frequency survey and had to follow a low FODMAP diet with a dietary guide education for 3 weeks. After the diet, a telephone questionnaire was conducted to evaluate adherence and treatment efficiency. Results: Mean of the population age was 56.5 (21 – 83 years) with a sex ratio of almost 1⁄4. The initial food survey showed a large consumption of white bread and fruits. Tolerance to rich in FODMAP foods was variable among patients. Up to 97% of patients adhered to the low FODMAP diet. A decrease in abdominal pain in 88% of cases and in bloating in 64.7% of cases (p = 0.007) were noted after the diet. Conclusion: In our patients, the low FODMAP diet showed satisfactory results with good adherence, and improvement of IBS symptoms. However, it is important to note the difficulty of a long-term diet in a population with a variable alimentary habit. Key words: low FODMAP diet; irritable bowel syndrome, applicability, Tunisia

A Population Survey of Dietary Attitudes towards Gluten

It is unclear how the prevalence of people who believe the gluten-free diet (GFD) to be generally healthy (“Lifestylers”) is impacting the overall rates of self-reported gluten sensitivity (GS). We repeated a population survey from 2012 in order to examine how attitudes towards GS have changed over time. Our survey (N = 1004) was administered in Sheffield (UK) in 2015, replicating the 2012 experiment. The questionnaire included a food frequency survey and assessed self-reported GS as well as associated variables (prevalence, current diet, pre-existing conditions, etc.). The overall rates of key variables and chi-squared analysis in comparison to the previous survey were as follows: self-reported GS was 32.8% (previously 12.9%, p < 0.001), pre-existing coeliac disease (CD) was 1.2% (previously 0.8%, p = 0.370), following a GFD was 3.7% (previously 3.7%, p = 0.997). Self-reported GS was positively associated with some pre-existing conditions, including anxiety, depression, chronic fatigue, headaches, and other food allergies/intolerances (including irritable bowel syndrome (IBS); chi-squared analyses, all p < 0.001). Over a 3-year period, the fraction of people who self-reported GS increased by over 250%. Despite this, arguably more meaningful indications of underlying physiological GS remained comparable. This research suggests that the public perception of gluten is causing a marked increase in the number of people who erroneously believe they are sensitive to it.

Students’ adherence to dietary recommendations and their food consumption habits

Background: Habitual behavior rather than intention has been linked to food intake patterns. Aim: The purpose of this study was to examine the adherence to dietary recommendations in university students and to analyze whether habit strength predicts food consumption. Methods: A student sample of the University (University of Hohenheim) was recruited ( n = 103; age range 18–30 years). Habit strength for consuming the food groups fruits, vegetables, whole grains, milk, meat, convenience foods, sugary and savory snacks, water and sugar-sweetened beverages was measured using a questionnaire. Food intake was measured via a self-administered online food frequency survey two weeks later, which was then compared to dietary recommendations. For associations of habit strength and consumption, Kendall’s Tau-c correlation coefficient was calculated. Results: The majority of students failed to meet the recommendations for all food groups except meat, eggs, oil, fat, and water. Only 4.2% of men (15.4% of women) consumed the recommended daily amount of vegetables. Fruit recommendations were met by 20.8% of men (43.6% of women). Habit strength was significantly associated with the consumption of most food groups. Conclusion: Adhering to dietary recommendations appeared to be difficult. Educational efforts should be undertaken to improve students’ diet considering habit strength as an important determinant of food intake.