A definite prosauropod dinosaur from the Lower Elliot Formation (Norian: Upper Triassic) of South Africa

Main articleA new sauropodomorph dinosaur specimen is described and identified as a prosauropod. It is tentatively placed as the sister taxon of Riojasaurus incertus from Argentina. The systematic position of all commonly accepted sauropodomorph dinosaurs from the Lower Elliott Formation of South Africa is reviewed and it is found that none can be positively identified as prosauropod. Euskelosaurus browni is a nomen dubium based on material that cannot be identified further than Sauropodomorpha. Blikanasaurus cromptoni and Antetonitrus ingenipes are basal sauropods. Melanorosaurus readi is probably another basal sauropod but opinion remains divided. Plateosauravus cullingworthi presents conflicting character data and at present is classified as Sauropodomorpha incertae sedis. Consequently the specimen described here represents the only prosauropod specimen currently recognized in the Lower Elliot Formation of South Africa.NRF postdoctoral fellowship

A new theropod dinosaur from the Early Jurassic of South Africa and its implications for the early evolution of theropods

A new theropod, Dracovenator regenti, from the upper Elliot Formation is described, based upon a fragmentary skull. It can be diagnosed on the basis of a bilobed fossa on the lateral surface of the premaxilla that is connected to the alveolar margin by a narrow channel, the presence of a deep, oblique, lateral notch on the articular and hypertrophied dorsal processes on the articular. Other aspects of its morphology display a mosaic of coelophysoid and advanced theropod characteristics. A cladistic analysis of basal Theropoda, including the new taxon finds that the new taxon is closely related to Dilophosaurus wetherilli and Zupaysaurus rougieri although the clade formed by these three taxa is not robustly supported. It also finds that Coelophysoidea sensu lato is paraphyletic with respect to Ceratosauria + Tetanurae but that this topology is not a significantly better explanation of the data than an inclusive, monophyletic Coelophysoidea.Welles Fun

New information on the palate and lower jaw of Massospondylus (Dinosauria: Sauropodomorpha)

Additional anatomical details of the palate and lower jaw of the prosauropod dinosaur Massospondylus Owen are documented on the basis of a previously undescribed skull from the upper Elliot Formation. The palate is generally similar to that of other early sauropodomorphs, but can be shown to differ from those of Plateosaurus, Lufengosaurus and Thecodontosaurus in several respects. For example, Massospondylus lacks the well-developed palatine boss seen in Plateosaurus and the pneumatic recess that is present on the ectopterygoid of Thecodontosaurus. In addition, Massospondylus possesses an expanded medioventral premaxillary process that is much larger than that of any other basal sauropodomorph.The Royal Society of London and the Palaeontological Research Fund of the Natural History Museu

Preliminary report of a large theropod dinosaur trackway in Clarens Formation sandstone (Early Jurassic) in the Paul Roux district, northeastern Free State, South Africa

An isolated fallen block of Clarens Formation sandstone near the small northeastern Free State town of Paul Roux preserves part of the trackway of a bipedal dinosaur. Although well known as a local curiosity, this trackway has not previously been formally reported or described. It consists of five successive paces of what is interpreted as a medium-sized to large theropod dinosaur, and represents the largest known theropod trackway in the ‘Stormberg’ sequence in South Africa. The tracks are assigned to the ichnotaxon Grallator sp., and show similarities to North American tracks of comparable age originally described as Dilophosauripus. Until now no body fossils of a likely candidate trackmaker were known, but elsewhere in this volume a possible candidate is described by the second author

New specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 from the Early Jurassic of South Africa

We describe new specimens of the basal ornithischian dinosaur Lesothosaurus diagnosticus Galton, 1978 collected from a bone bed in the Fouriesburg district of the Free State, South Africa. The material was collected from the upper Elliot Formation (Early Jurassic) and represents the remains of at least three different individuals. These individuals are larger in body size than those already known in museum collections and offer additional information on cranial ontogeny in the taxon. Moreover, they are similar in size to the sympatric taxon Stormbergia dangershoeki. The discovery of three individuals at this locality might imply group-living behaviour in this early ornithischian

A Uniform Analysis of the Ly-alpha Forest at z=0 - 5: V. The extragalactic ionizing background at low redshift

In Paper III of our series "A Uniform Analysis of the Ly-alpha forest at z=0 - 5", we presented a set of 270 quasar spectra from the archives of the Faint Object Spectrograph on the Hubble Space Telescope. A total of 151 of these spectra, yielding 906 lines, are suitable for using the proximity effect signature to measure J(\nu_0), the mean intensity of the hydrogen-ionizing background radiation field, at low redshift. Using a maximum likelihood technique and the best estimates possible for each QSO's Lyman limit flux and systemic redshift, we find J(\nu_0)= 7.6^+9.4_-3.0 x 10^-23 ergs s^-1 cm^-2 Hz^-1 sr^-1 at at 0.03 < z < 1.67. This is in good agreement with the mean intensity expected from models of the background which incorporate only the known quasar population. When the sample is divided into two subsamples, consisting of lines with z 1, the values of J(\nu_0) found are 6.5^+38._-1.6 x 10^-23 ergs s^-1 cm^-2 Hz^-1 sr^-1, and 1.0^+3.8_-0.2 x 10^-22 ergs s^-1 cm^-2 Hz^-1 sr^-1, respectively, indicating that the mean intensity of the background is evolving over the redshift range of this data set. Relaxing the assumption that the spectral shapes of the sample spectra and the background are identical, the best fit HI photoionization rates are found to be 6.7 x 10^-13 s^-1 for all redshifts, and 1.9 x 10^-13 s^-1 and 1.3 x 10^-12 s^-1 for z 1, respectively. This work confirms that the evolution of the number density of Ly-alpha lines is driven by a decrease in the ionizing background from z ~ 2 to z ~ 0 as well as by the formation of structure in the intergalactic medium. (Abridged)Comment: 71 LaTeX pages, 20 encapsulated Postscript figures, Accepted for publication in ApJ, Figure 4 available at http://lithops.as.arizona.edu/~jill/QuasarSpectra/ or http://hea-www.harvard.edu/QEDT/QuasarSpectra

The UK clinical aptitude test and clinical course performance at Nottingham: a prospective cohort study

Background The UK Clinical Aptitude Test (UKCAT) was introduced in 2006 as an additional tool for the selection of medical students. It tests mental ability in four distinct domains (Verbal Reasoning, Quantitative Reasoning, Abstract Reasoning, and Decision Analysis), and the results are available to students and admission panels in advance of the selection process. Our first study showed little evidence of any predictive validity for performance in the first two years of the Nottingham undergraduate course. The study objective was to determine whether the UKCAT scores had any predictive value for the later parts of the course, largely delivered via clinical placements. Methods Students entering the course in 2007 and who had taken the UKCAT were asked for permission to use their anonymised data in research. The UKCAT scores were incorporated into a database with routine pre-admission socio-demographics and subsequent course performance data. Correlation analysis was followed by hierarchical multivariate linear regression. Results The original study group comprised 204/254 (80%) of the full entry cohort. With attrition over the five years of the course this fell to 185 (73%) by Year 5. The Verbal Reasoning score and the UKCAT Total score both demonstrated some univariate correlations with clinical knowledge marks, and slightly less with clinical skills. No parts of the UKCAT proved to be an independent predictor of clinical course marks, whereas prior attainment was a highly significant predictor (p <0.001). Conclusions This study of one cohort of Nottingham medical students showed that UKCAT scores at admission did not independently predict subsequent performance on the course. Whilst the test adds another dimension to the selection process, its fairness and validity in selecting promising students remains unproven, and requires wider investigation and debate by other schools

Careless Responding in Crowdsourced Alcohol Research: A Systematic Review and Meta-Analysis of Practices and Prevalence

Crowdsourcing - the process of using the internet to outsource research participation to “workers” - has considerable benefits, enabling research to be conducted quickly, efficiently, and responsively, diversifying participant recruitment, and allowing access to hard-to-reach samples. One of the biggest threats to this method of online data collection however is the prevalence of careless responders who can significantly affect data quality. The aims of this preregistered systematic review and meta-analysis were: (a) to examine the prevalence of screening for careless responding in crowdsourced alcohol-related studies; (b) to examine the pooled prevalence of careless responding; and (c) to identify any potential moderators of careless responding across studies. Our review identified 96 eligible studies (~126,130 participants), of which 51 utilized at least one measure of careless responding, 53.2%, 95% CI 42.7%–63.3%; ~75,334 participants. Of these, 48 reported the number of participants identified by careless responding method(s) and the pooled prevalence rate was ~11.7%, 95% CI 7.6%–16.5%. Studies using the MTurk platform identified more careless responders compared to other platforms, and the number of careless response items was positively associated with prevalence rates. The most common measure of careless responding was an attention check question, followed by implausible response times. We suggest that researchers plan for such attrition when crowdsourcing participants and provide practical recommendations for handling and reporting careless responding in alcohol research