The Complete Local Volume Groups Sample - II. A study of the Central Radio Galaxies in the High−-Richness Sub-sample

We present a study of the radio properties of the dominant early-type galaxies in 26 galaxy groups, the high-richness sub-sample of the Complete Local-volume Groups Sample (CLoGS). Combining new 610 MHz and 235 MHz observations of 21 groups from the Giant Metrewave Radio Telescope (GMRT) with archival GMRT and Very Large Array (VLA) survey data, we find a high detection rate, with 92% of the dominant galaxies hosting radio sources. The sources have a wide range of luminosities, 10$^{20}$ $-$ 10$^{24}$ W/Hz in the 235 and 610 MHz bands. The majority (54%) are point-like, but 23% have radio jets, and another 15% are diffuse radio sources with no clear jet/lobe morphology. The spectral index of the detected radio sources ranges from very flat values of ~0.2 to typical radio synchrotron spectra of ~0.9 with only two presenting steep radio spectra with $\alpha_{235}^{610}$ > 1. We find that jet sources are more common in X-ray bright groups, with radio non-detections found only in X-ray faint systems. Radio point sources appear in all group environments irrespective of their X-ray properties or spiral fraction. We estimate the mechanical power (Pcav) of the jet sources in the X-ray bright groups to be 10$^{41}$ $-$ 10$^{43}$ erg/s, with the two large-scale jet systems (NGC 193 and NGC 4261) showing jet powers two orders of magnitude greater than the radiative losses from the cool cores of their groups. This suggests that central AGN are not always in balance with cooling, but may instead produce powerful periodical bursts of feedback heating.Comment: Accepted for publication by MNRAS, 19 Manuscript pages with 8 tables and 8 figures, plus 13 pages of appendice

Alveolar Osteitis: A Comprehensive Review of Concepts and Controversies

Alveolar osteitis, “dry socket”, remains amongst the most commonly encountered complications following extraction of teeth by general dentists and specialists. A great body of literature is devoted to alveolar osteitis addressing the etiology and pathophysiology of this condition. In addition numerous studies are available discussing methods and techniques to prevent this condition. To this date though great controversy still exists regarding the appropriate terminology used for this condition as well as the actual etiology, pathophysiology, and best methods of prevention and treatment. This article is a comprehensive critical review of the available literature addressing the concepts and controversies surrounding alveolar osteitis. We aim to assist the dental health care professional with patient preparation and management of this commonly encountered postoperative condition should be encountered

New insights into the evolution of the FR I radio galaxy 3C 270 (NGC 4261) from VLA and GMRT radio observations

We present Giant Metrewave Radio Telescope (GMRT) 240 MHz observations of the nearby luminous FR I radio source 3C 270, in the group-central elliptical NGC 4261. Combining these data with reprocessed Very Large Array (VLA) 1.55 and 4.8 GHz observations, we produce spectral index maps that reveal a constant spectral index along the jets and a gradual steepening from the ends of the jets through the lobes towards the nucleus. A Jaffe & Perola (JP) model fitted to the integrated spectrum of the source gives an asymptotic low-frequency index of $\alpha_{inj}=0.53_{-0.02}^{+0.01}$, while JP models fitted to the observed spectral index trend along the lobes allow us to estimate radiative ages of $\sim29$ Myr and $\sim37$ Myr for the west and east lobes respectively. Our age estimates are a factor of two lower than the 75-Myr upper limit derived from X-ray data (O'Sullivan et al. 2011). We find unlikely the scenario of an early supersonic phase in which the lobe expanded into the ISM at approximately Mach 6 (3500 km s$^{-1}$), and suggest that either the source underwent multiple AGN outbursts with possible large changes in jet power, or possibly that the source age that we find is due to a backflow that transports young electrons from the jet tips through the lobes toward the nucleus relatively quickly. We calculate that in the lobes the energy ratio of non-radiating to radiating particles is $\sim4-24$ indicating significant gas entrainment. If the lobes are in pressure balance with their surroundings, the total energy required to heat the entrained material is $10^{58}$ erg, $\sim$40% of the total enthalpy of the lobes.Comment: 14 pages, 11 figures, 8 tables. Accepted for publication by MNRAS. Revised throughout in response to referee's comment

Injuries and adolescent ballet dancers: current evidence, epidemiology, and intervention

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Background: It has been consistently reported in the literature that adolescent dancers have a high injury prevalence. Most injuries are reported as overuse onset and the most affected body region is the lower limb. Growth and maturation have been reported as non-modifiable whereas poor motor performance in power and strength as modifiable risk factors. Methods: A systematic review was conducted to evaluate the association of growth, maturation and overuse injuries in aesthetic sports/disciplines. This was followed by a prospective cross­ sectional study to assess the relationship of injury incidence and primarily countermovement­ jump (CMJ), a valid indicator of motor performance, and secondarily gender differences and maturity status. Three randomized controlled trials (RCT) were conducted to assess 1) the feasibility of a trial in a vocational environment, 2) to conduct power and sample calculation and 3) to assess the effects a neuromuscular injury prevention intervention on countermovement-jump, reactive strength-index (RSI), isometric mid-thigh pull (IMTP) and inter-limb asymmetry (ASYM) in adolescent ballet dancers. Results: The results from the systematic review were inconclusive, due to the heterogeneity of the studies, the research design, and sample size. The cross-sectional study revealed no association between injury incidence and CMJ; and there was no statistically significant gender or maturity status differences in injury incidence. The RCT results demonstrated no statistically significant between-group differences in the mean scores of all the measured parameters. Both groups revealed potentially clinically meaningful difference, between pre and post intervention scores in CMJ and IMTP. No harm was observed, however, less injuries were reported for the intervention group during the duration of the trial. Conclusion: The results of this investigation indicate no association of CMJ and injury incidence, and no gender or maturity status differences in injury incidence were observed. The RCT results indicate no significant between-group post intervention differences in all the assessed parameters. The observations about the potentially clinically meaningful results in power and strength, may warrant further investigation in this area of study. Research in injuries and dance is particularly important, given the high prevalence, suggesting that more work is needed in this field to ameliorate the detrimental effects of injury in this population.Elmhurst Ballet Schoo

Radio properties of a complete sample of nearby groups of galaxies

Much of the evolution of galaxies takes place in groups where feedback has the greatest impact on galaxy formation. By using an optically selected, statistically complete sample of 53 nearby groups (CLoGS), observed at radio (GMRT) and X-ray (Chandra and XMM-Newton) frequencies, we aim to characterise the radio-AGN population in groups and examine their impact on the intra-group gas and member galaxies. In this dissertation, low-frequency GMRT radio images of the nearby (<80 Mpc) central brightest group ellipticals from the high richness CLoGS sub-sample are presented for the first time at 235 and 610 MHz. Using the sensitivity to older electron populations at 235 MHz and the resolution of 610 MHz as a key to identify past and current AGN activity, a detailed analysis of the radio properties for each of the central group radio sources is performed, with the results being in addition combined with findings from the X-ray observations

Educational Activities Concerning Folk/Popular Culture in Greek Primary School Websites

Folk/Popular culture comprises a many-sided and complex term, existing in both its traditional (Folk) and contemporary dimension (Popular). Many of its aspects can be traced in Primary Education school books, but in many cultural school displays as well. Student participation in cultural oriented activities encourages enculturation, the awareness of belonging in one or many cultural groups, and, successively, an understanding of one’s cultural identity. This article presents the results of research conducted all over Greece concerning educational programs and activities about folk/popular culture as shown in the websites of Greek public and private Primary Schools and Kindergartens, utilizing online data collection