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The Rapid ASKAP Continuum Survey (RACS) is the first large-area survey to be conducted with the full 36-antenna Australian Square Kilometre Array Pathfinder (ASKAP) telescope. RACS will provide a shallow model of the ASKAP sky that will aid the calibration of future deep ASKAP surveys. RACS will cover the whole sky visible from the ASKAP site in Western Australia and will cover the full ASKAP band of 700–1800 MHz. The RACS images are generally deeper than the existing NRAO VLA Sky Survey and Sydney University Molonglo Sky Survey radio surveys and have better spatial resolution. All RACS survey products will be public, including radio images (with
15 arcsec resolution) and catalogues of about three million source components with spectral index and polarisation information. In this paper, we present a description of the RACS survey and the first data release of 903 images covering the sky south of declination
made over a 288-MHz band centred at 887.5 MHz.
Clement of Rome, traditionally the fourth pope and third successor to Peter, is a mysterious figure whose historical traces are as slight as his reputation and fame are great. His authentic letter to the Corinthian Church from 96 is of great importance; his legend and cult have grown great over the centuries, notably in connection with the Basilica di San Clemente in Rome. Excavations underneath the current twelfth-century basilica led to the discovery of an original fourth–fifth-century church, and beneath it are Roman buildings of the first and second centuries. At this site, visitors can journey back in time from the present day street level, through twelfth-and fourth-century strata, all the way down to the first-century Roman level. Such a journey takes the visitor through a series of complex historical realities, matched in their complexity by the history and narratives surrounding Clement himself. A study of Clement's legends, his writing, and the historical context in which he carried out his priestly life reveal much about the early Church in Rome, allowing us to make contact with a colleague of St. Peter himself.
Contextualizing Clement in Rome
Although his biographical information is elusive, Clement is sometimes linked to the Roman patrician Titus Flavius Clemens (50–95) and his wife Domitilla. Titus was a nephew of the former emperor Vespasianus (69–79) and as such a great nephew of the emperor Domitian (81–96), who nonetheless put Titus to death and exiled his wife in 96 on the grounds of godlessness and deviation into Jewish practices. Legend has sometimes associated Clement with Titus Flavius Clemens himself, though more frequently with a freedman of his household. Scholars now argue that the source of their treason would have been a refusal to sacrifice to the cult of Domitian's divine genius.
Though Titus Flavius Clemens is not now considered to have been Christian, many hypothesize that his wife indeed was of the Christian faith. Returning from exile after the death of Domitian, she may have been responsible for the donation of lands to the Christian community that eventually formed the Catacombe di Domitilla on the Appian Way.
Monarch butterflies (Danaus plexippus (Linnaeus) (Lepidoptera: Nymphalidae)) in eastern North America migrate each year from overwintering areas in Mexico to cover a large breeding distribution across the United States of America and southern Canada. In 2012, monarch butterflies migrated well beyond their usual range, resulting in an extended breeding distribution compared to typical years. We used stable isotope (δ2H, δ13C) measurements in wing chitin to determine the area of natal origin of these butterflies. Most monarch butterflies collected in May, June, and July from Manitoba and Alberta, Canada had natal origins in the North American Midwest. Monarch butterflies collected in Alberta and Saskatchewan, Canada in August and September had local natal origins indicating successful recruitment of offspring from colonising individuals. However, it is unknown whether these offspring migrated successfully to overwintering areas. Our work highlights the ability of monarch butterflies to colonise distant breeding areas and demonstrates how stable isotopes can be used to understand the dynamics of range-edge populations.
Very metal-poor stars ([Fe/H] < –2.0) inform our understanding of the formation and evolution of the Galaxy, and the physical conditions in the earliest star-forming environments of the Universe. They play an integral part in the paradigms of stellar populations, stellar archaeology, and near-field cosmology. We review the carbon-rich and carbon-normal sub-populations of the most iron-poor stars, providing insight into chemical enrichment at the earliest times in the Universe. We also discuss the role of very metal-poor stars in providing insight into the Galaxy’s halo, thick disk, and bulge, and the promise they hold for the future. A comparison between the abundances obtained for the nine most Fe-poor stars ([Fe/H] < –4.5) (all but one of which is C-rich) with abundances obtained from far-field cosmology suggests that the former are the most chemically primitive objects yet observed and probably older than the DLA- and sub-DLA systems for which data are currently available from far-field studies.
Task-based language assessment (TBLA) has generated interest since the early 1990s, primarily in conjunction with the ongoing development of task-based language teaching (TBLT) and the pursuit of developing appropriate testing models for this approach to pedagogy (Norris, 2002, 2009). However, tasks also offer considerable advantages for language assessment, beyond their obvious relevance within TBLT classes and programs. In fact, major innovations in the general domain of language assessment over the past two decades have occurred in conjunction with the introduction of tasks into assessment design, largely in response to the need for tests that better represent examinees’ abilities to use the language (Mislevy, Steinberg, & Almond, 2002), but also because tasks offer a meaningful space for language teachers, testers, learners, and others to examine, understand, and improve language learning endeavors (Van Gorp & Deygers, 2013). This article reviews the considerable range of current uses for TBLA, illustrating different types of assessment with concrete examples and highlighting distinct roles for tasks as a basic unit of analysis in test design, interpretation, and intended consequence. Ultimately, it argues that tasks offer a fundamental, though not exclusive, foundation for useful language assessment, and that task-based assessment, though challenging, is probably worth the effort.
Stars in low-mass dwarf galaxies show a larger range in their chemical properties than those in the Milky Way halo. The slower star formation efficiency make dwarf galaxies ideal systems for testing nucleosynthetic yields. Not only are alpha-poor stars found at lower metallicities, and a higher fraction of carbon-enhanced stars, but we are also finding stars in dwarf galaxies that appear to be iron-rich. These are compared with yields from a variety of supernova predictions.
Vitamin D deficiency has been implicated in the aetiology of infectious diseases and metabolic syndrome. These diseases are prevalent in the African and Asian-Indian populations of South Africa; however, there is limited data on 25-hydroxyvitamin D (25(OH)D) concentrations in these populations. The aim of the present study was to assess the vitamin D status and its predictors in healthy adults in Johannesburg. We assessed the vitamin D status of 730 adult African and Asian-Indian subjects residing in Johannesburg. The contributions of sun exposure, season, dietary intake of Ca and vitamin D, total body fat and body fat distribution to 25(OH)D concentrations were assessed. The concentrations of 25(OH)D were measured by HPLC. The contribution of 25(OH)D3 to total 25(OH)D concentrations was assessed. The mean age of the subjects was 42·6 (sd 13·1) years (range: 18–65). Concentrations of 25(OH)D < 30 nmol/l were found in 28·6 % of the Asian-Indian subjects in comparison with 5·1 % of the African subjects (P< 0·0001). Parathyroid hormone (PTH) concentrations were negatively associated with 25(OH)D concentrations, while season and sun exposure were positive predictors explaining 16 % of the variance in 25(OH)D concentrations (P< 0·0001) in the African subjects. In the Asian-Indian subjects, PTH concentrations were negatively associated with 25(OH)D concentrations, while male sex, season and Ca supplementation were positive predictors and explained 17 % of the variance in 25(OH)D concentrations (P< 0·0001). In the multivariate regression analysis, neither total body fat nor body fat distribution was predictive of 25(OH)D concentrations in either group. In conclusion, factors such as sun exposure, dietary supplement use and ethnicity are important determinants of plasma 25(OH)D concentrations.
The present paper examines dietary intake and body composition in antiretroviral (ARV)-naïve HIV-positive compared with HIV-negative South African women, as well as the impact of disease severity on these variables.
Baseline data from a longitudinal study assessing bone health in HIV-negative and HIV-positive premenopausal South African women over 18 years of age were used. Anthropometry and body composition, measured by dual energy X-ray absorptiometry, were analysed together with dietary intake data assessed using an interviewer-based quantitative FFQ.
Soweto, Johannesburg, South Africa.
Black, urban South African women were divided into three groups: (i) HIV-negative (HIV−; n 98); (ii) HIV-positive with preserved CD4 counts (HIV+ non-ARV; n 74); and (iii) HIV-positive with low CD4 counts and due to start ARV treatment (HIV+ pre-ARV; n 75).
The prevalence of overweight and obesity was high in this population (59 %). The HIV+ pre-ARV group was lighter and had a lower BMI than the other two groups (all P < 0·001). HIV+ pre-ARV women also had lower fat and lean masses and percentage body fat than their HIV− and HIV+ non-ARV counterparts. After adjustment, there were no differences in macronutrient intakes across study groups; however, fat and sugar intakes were high and consumption of predominantly refined food items was common overall.
HIV-associated immunosuppression may be a key determinant of body composition in HIV-positive women. However, in populations with high obesity prevalence, these differences become evident only at advanced stages of infection.
Below [Fe/H] = −3.0, there is an enormous range in [C/Fe]. We discuss the properties of C-rich ([C/Fe] > +0.7) and C-normal ([C/Fe] ≤ +0.7) stars in this regime, and suggest that there existed two different gas cooling channels in the very early Universe.
This talk covers preliminary work in which we apply a strictly differential line-by-line chemical abundance analysis to high quality UVES spectra of the globular cluster NGC 6752. We achieve extremely high precision in the measurement of relative abundance ratios. Our results indicate that the observed abundance dispersion exceeds the measurement uncertainties and that many pairs of elements show significant correlations when plotting [X1/H] vs. [X2/H]. Our tentative conclusions are that either NGC 6752 is not chemically homogeneous at the ≃0.03 dex level or the abundance variations and correlations signify star-to-star He abundance variations.
The present study aimed to assess the relationship between dietary habits, change in socio-economic status and BMI Z-score and fat mass in a cohort of South African adolescents.
In the longitudinal study, data were collected at ages 13, 15 and 17 years on a birth cohort who have been followed since 1990. Black participants with complete dietary habits data (breakfast consumption during the week and at weekends, snacking while watching television, eating main meal with family, lunchbox use, number of tuck shop purchases, fast-food consumption, confectionery consumption and sweetened beverage consumption) at all three ages and body composition data at age 17 years were included in the analyses. Generalized estimating equations were used to test the associations between individual longitudinal dietary habits and obesity (denoted by BMI Z-score and fat mass) with adjustments for change in socio-economic status between birth and age 12 years.
Birth to Twenty (Bt20) study, Soweto-Johannesburg, South Africa.
Adolescents (n 1298; 49·7 % male).
In males, the multivariable analyses showed that soft drink consumption was positively associated with both BMI Z-score and fat mass (P < 0·05). Furthermore, these relationships remained the same after adjustment for socio-economic indicators (P < 0·05). No associations were found in females.
Longitudinal soft drink consumption was associated with increased BMI Z-score and fat mass in males only. Fridge ownership at birth (a proxy for greater household disposable income in this cohort) was shown to be associated with both BMI Z-score and fat mass.
Factors resulting in high risk for cardiovascular disease have been well studied in high income countries, but have been less well researched in low/middle income countries. This is despite robust theoretical evidence of environmental transitions in such countries which could result in biological adaptations that lead to increased hypertension and cardiovascular disease risk. Data from the South African Birth to Twenty cohort, Bone Health sub-sample (n=358, 47% female), were used to model associations between household socioeconomic status (SES) in infancy, household/neighbourhood SES at age 16 years, and systolic blood pressure (multivariate linear regression) and risk for systolic pre-hypertension (binary logistic regression). Bivariate analyses revealed household/neighbourhood SES measures that were significantly associated with increased systolic blood pressure. These significant associations included improved household sanitation in infancy/16 years, caregiver owning the house in infancy and being in a higher tertile (higher SES) of indices measuring school problems/environment or neighbourhood services/problems/crime at 16 years of age. Multivariate analyses adjusted for sex, maternal age, birth weight, parity, smoking, term birth, height/body mass index at 16 years. In adjusted analyses, only one SES variable remained significant for females: those in the middle tertile of the crime prevention index had higher systolic blood pressure (β=3.52, SE=1.61) compared with the highest tertile (i.e. those with the highest crime prevention). In adjusted analyses, no SES variables were significantly associated with the systolic blood pressure of boys, or with the risk of systolic pre-hypertension in either sex. The lack of association between SES and systolic blood pressure/systolic pre-hypertension at age 16 years is consistent with other studies showing an equalization of adolescent health inequalities. Further testing of the association between SES and systolic blood pressure would be recommended in adulthood to see whether the lack of association persists.
To investigate predictors of adolescent obesity in rural South Africa.
Cross-sectional study. Height, weight and waist circumference were measured using standard procedures. Overweight and obesity in adolescents aged 10–17 years were assessed using the International Obesity Taskforce cut-offs, while the WHO adult cut-offs were used for participants aged 18–20 years. Waist-to-height ratio of >0·5 defined central obesity in those at Tanner stages 3–5. Linear and logistic regression analysis was used to evaluate risk factors.
Agincourt sub-district, rural South Africa.
Participants (n 1848) were aged 10–20 years.
Combined overweight and obesity was higher in girls (15 %) than boys (4 %), as was central obesity (15 % and 2 %, respectively). With regard to overweight/obesity, fourfold higher odds were observed for girls and twofold higher odds were observed for participants from households with the highest socio-economic status (SES). The odds for overweight/obesity were 40 % lower if the household head had not completed secondary level education. For central obesity, the odds increased 10 % for each unit increase in age; girls had sevenfold higher odds v. boys; post-pubertal participants had threefold higher odds v. pubertal participants; those with older mothers aged 50+ years had twofold higher odds v. those whose mothers were aged 35–49 years; those in highest SES households had twofold higher odds v. those in lowest SES households.
In rural South Africa, adolescent females are most at risk of obesity which increases with age and appears to be associated with higher SES. To intervene effectively, it is essential to understand how household factors influence food choice, diet and exercise.
Longer-term follow-up of patients with borderline personality disorder have found favourable clinical outcomes, with long-term reduction in symptoms and diagnosis.
We examined the 6-year outcome of patients with borderline personality disorder who were randomised to 1 year of cognitive–behavioural therapy for personality disorders (CBT–PD) or treatment as usual (TAU) in the BOSCOT trial, in three centres across the UK (trial registration: ISRCTN86177428).
In total, 106 participants met criteria for borderline personality disorder in the original trial. Patients were interviewed at follow-up by research assistants masked to the patient's original treatment group, CBT–PD or TAU, using the same measures as in the original randomised trial. Statistical analyses of data for the group as a whole are based on generalised linear models with repeated measures analysis of variance type models to examine group differences.
Follow-up data were obtained for 82% of patients at 6 years. Over half the patients meeting criteria for borderline personality disorder at entry into the study no longer did so 6 years later. The gains of CBT–PD over TAU in reduction of suicidal behaviour seen after 1-year follow-up were maintained. Length of hospitalisation and cost of services were lower in the CBT–PD group compared with the TAU group.
Although the use of CBT–PD did not demonstrate a statistically significant cost-effective advantage, the findings indicate the potential for continued long-term cost-offsets that accrue following the initial provision of 1 year of CBT–PD. However, the quality of life and affective disturbance remained poor.
Assessment of vitamin D status in a cohort of healthy 10-year-old urban children and the factors that influence vitamin D status in these children.
A cross-sectional study. Blood samples were collected across four seasons of the year for the biochemical determination of serum 25-hydroxyvitamin D [25(OH)D]. Anthropometric measurements (height and weight), BMI and total fat and lean mass (determined by the dual energy X-ray absorptiometry) were measured. 25(OH)D concentrations were assessed by chemiluminescent assay.
Study of children in the Greater Johannesburg area of South Africa who form the Bone Health sub-cohort of the longitudinal Birth to Twenty cohort.
Three hundred and eighty-five children who form the Bone Health sub-cohort of the longitudinal Birth to Twenty cohort.
White children had significantly higher 25(OH)D than their black peers (120·0 (sd 36·6) nmol/l v. 93·3 (sd 34·0) nmol/l, respectively). Seasonal variations in 25(OH)D levels were found only in white children, with 25(OH)D levels being significantly higher in white than in black children during the autumn and summer months. In multiple regression analysis, season, ethnicity, sex and total fat mass were the factors found to have an influence on 25(OH)D. Vitamin D deficiency (7 %) and insufficiency (19 %) were uncommon among the 10-year-old children.
Vitamin D supplementation or fortification is not warranted in healthy children living in Johannesburg. However, further studies need to confirm this in other regions of the country, especially in those living further south and with less sunshine during the winter months.
When in the late 1990s we set out to review the accumulated research on second language (L2) instructional effectiveness, it was with a sense – though no certainty – that a journey into the uncharted territory of systematic research synthesis would eventually prove worth the effort. In order to find a fitting methodology, and in the absence of any guidance within applied linguistics, we willingly delved into challenging techniques and debates from other disciplines. A few years later, we had to search long and hard to find enough synthesists working on language learning and teaching issues to warrant a book, but we did, and we saw that new effort as an important, if initial, step towards the adoption and adaptation of research synthesis, and particularly the subset of methods known as meta-analysis, to the problems of applied linguistics. Now, some ten years after our first publication on the topic, applications of meta-analysis have increased dramatically in the field, as this Timeline clearly shows. For some topics (e.g. interaction, corrective feedback), we have even seen several studies replicating and building on each other. We are pleased with these developments and welcome the efforts of the field to engage in rigorous and meaningful reviews of L2 research, with an eye towards cumulative explanation of key phenomena. At the same time, we also hope that researchers will avail themselves of the full potential of systematic research synthesis, which considerably transcends the narrower domain of meta-analysis and includes other quantitative as well as qualitative methods that more fully enable the task of synthesizing accumulated knowledge in the increasingly diverse research landscape of applied linguistics.