Anatomy and origin of authochthonous late Pleistocene forced regression deposits, east Coromandel inner shelf, New Zealand: implications for the development and definition of the regressive systems tract

High-resolution seismic reflection data from the east Coromandel coast, New Zealand, provide details of the sequence stratigraphy beneath an autochthonous, wave dominated inner shelf margin during the late Quaternary (0-140 ka). Since c. 1 Ma, the shelf has experienced limited subsidence and fluvial sediment input, producing a depositional regime characterised by extensive reworking of coastal and shelf sediments during glacio-eustatic sea-level fluctuations. It appears that only one complete fifth-order (c. 100 000 yr) depositional sequence is preserved beneath the inner shelf, the late Pleistocene Waihi Sequence, suggesting any earlier Quaternary sequences were mainly cannibalised into successively younger sequences. The predominantly Holocene-age Whangamata Sequence is also evident in seismic data and modern coastal deposits, and represents an incomplete depositional sequence in its early stages of formation. A prominent aspect of the sequence stratigraphy off parts of the east Coromandel coast is the presence of forced regressive deposits (FRDs) within the regressive systems tract (RST) of the late Pleistocene Waihi Sequence. The FRDs are interpreted to represent regressive barrier-shoreface sands that were sourced from erosion and onshore reworking of underlying Pleistocene sediments during the period of slow falling sea level from isotope stages 5 to 2 (c. 112-18 ka). The RST is volumetrically the most significant depositional component of the Waihi Sequence; the regressive deposits form a 15-20 m thick, sharp-based, tabular seismic unit that downsteps and progrades continuously across the inner shelf. The sequence boundary for the Waihi Sequence is placed at the most prominent, regionally correlative, and chronostratigraphically significant surface, namely an erosional unconformity characterised in many areas by large incised valleys that was generated above the RST. This unconformity is interpreted as a surface of maximum subaerial erosion generated during the last glacial lowstand (c. 18 ka). Although the base of the RST is associated with a prominent regressive surface of erosion, this is not used as the sequence boundary as it is highly diachronous and difficult to identify and correlate where FRDs are not developed. The previous highstand deposits are limited to subaerial barrier deposits preserved behind several modern Holocene barriers along the coast, while the transgressive systems tract is preserved locally as incised-valley fill deposits beneath the regressive surface of erosion at the base of the RST. Many documented late Pleistocene RSTs have been actively sourced from fluvial systems feeding the shelf and building basinward-thickening, often stacked wedges of FRDs, for which the name allochthonous FRDs is suggested. The Waihi Sequence RST is unusual in that it appears to have been sourced predominantly from reworking of underlying shelf sediments, and thus represents an autochthonous FRD. Autochthonous FRDs are also present on the Forster-Tuncurry shelf in southeast Australia, and may be a common feature in other shelf settings with low subsidence and low sediment supply rates, provided shelf gradients are not too steep, and an underlying source of unconsolidated shelf sediments is available to source FRDs. The preservation potential of such autochthonous FRDs in ancient deposits is probably low given that they are likely to be cannibalised during subsequent sea-level falls

New machine-marked tests for selection into core medical training: evidence from two validation studies

The objective of this study was to examine whether two machine-marked tests (MMTs), a clinical problem-solving test (CPS) and a situational judgement test (SJT, focusing on professional dilemmas), previously validated for selection into general practice (GP) training in the UK, could provide a valid selection methodology for shortlisting into core medical training (CMT). An exploratory longitudinal design was used to examine the psychometric properties of the MMTs for CMT applicants, and the correlation between MMT scores (time 1) and subsequent CMT interview outcomes (time 2). Independent samples from two consecutive years were used: in 2008 a retrospective analysis of data was used, while in 2009, doctors applying for CMT were asked to complete the MMTs for evaluation purposes. In 2008, a total of 1,711 doctors applied to both CMT and GP training and completed the MMTs. In 2009, a total of 2,265 doctors who applied for CMT completed the MMTs for evaluation purposes. The main outcome measure was the CMT applicants’ interview score. Both the CPS and SJT had good reliability and score distributions for 2008 and 2009 CMT samples, similar to the GP comparison samples. The MMTs were good predictors of performance in the CMT interviews (r0.56, p0.001 in 2008, and r0.61, p0.001 in 2009 for both MMTs combined) and offered incremental validity over the current shortlisting process. The GP MMTs offer an appropriate measurement methodology for selection into CMT, representing a significant innovation for developing selection methodology for CMT. Longer-term studies should be undertaken to assess the validity of all selection techniques used, in terms of CMT training outcome

Clastic Sediment Partitioning in a Cretaceous Delta System, Western Canada: Responses to Tectonic and Sea-Level Controls

The early–mid Cenomanian Dunvegan Formation represents a large delta complex that prograded at least 400 km from NW to SE. A regional stratigraphy based on marine transgressive surfaces and equivalent subaerial interfluves allows the formation to be subdivided into ten transgressive–regressive allomembers, labelled J to A in ascending order, each with an average duration of <200 ky. Analysis of stacking patterns and facies distributions of parasequences within allomembers allows transgressive, highstand, falling stage and lowstand systems tracts to be identified. Extensive valley systems that average 1–2 km wide and 21 m deep can be traced for up to 320 km across the top surfaces of allomembers H to E. In their lower 20–40 km, valleys are filled with muddy heterolithic tidal facies but this changes to fluvial-dominated multi-storey channel-fills further up-valley. Interfluve surfaces are marked by palaeosols, the character of which indicate a protracted hiatus with extensive physical, chemical and biological modification of the parent material. Changes in flexural subsidence rate are indicated by isopach patterns. Allomembers J–F have a sigmoidal prismatic geometry, successively offlapping to the SE. There is no evidence of thickening toward the orogen. In contrast, overlying allomembers E–A show progressive development of a depocentre along the western margin of the basin. The increasing accommodation rate on the updip coastal plain caused marine deltas to be starved of sediment, leading to progressive backstep of shorelines. Simultaneously, alluvial deposits within the depocentre show an upward increase in the proportion of subaqueous to subaerial facies, culminating in the incursion of brackish and finally marine waters. Thus tectonic subsidence rate had a first-order affect on both the volume of sediment available to build marine deltas and also on the local character of facies that accumulated on the coastal plain. The onset of flexural subsidence in allomember E appears to have resulted in subtle uplift of a forebulge, resulting in dramatic deflection of river systems. Despite the clear tectonic signature, successive transgressions and regressions involved similar horizontal displacements of the shoreline, regardless of subsidence rate. This suggests that modest eustatic changes also influenced the accommodation available. Based on the measured horizontal excursions of the shoreline, the vertical thickness of alluvial strata, and realistic alluvial gradients, an average eustatic excursion of about 24 m is calculated. The incision of valley systems is attributed in part to periods of eustatic fall. However, valleys seem too long to be explained by eustasy alone, and hence secular changes in discharge are postulated as an additional forcing factor. Climatic cycles in the Milankovitch band may have been responsible for both eustatic and discharge variations

Whole animal experiments should be more like human randomized controlled trials

Beverly S. Muhlhausler, Frank H. Bloomfield, Matthew W. Gillma

Developing standards for reporting implementation studies of complex interventions (StaRI): a systematic review and e-Delphi

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited

Understanding the unique contribution of aversion to risk taking in predicting drivers' self-reported speeding

Recent research has highlighted the importance of a drivers' attitude towards risk taking as one of the factors influencing safe driving behaviours. However, the strength of the relationship between drivers' attitude towards risk and their speeding may depend on other factors such as age, gender, and the frequency of driving, or even combinations of these factors. A survey completed by 400 students at the University of Southern Queensland found that aversion to risk taking was the single strongest predictor of self-reported speeding (sr2 = .07) even when competing against well known predictors such as driving efficacy, worry and concern, likelihood of accidents, personality traits (e.g., thrill seeking, dislike of driving, hazard-monitoring, fatigue proneness, and aggression) and coping variables (e.g., task-focused, reappraisal, emotion-focused, avoidance, and confrontive coping). Further analyses focused on the moderation effects of age, gender, and driving frequency. The first analysis found that for younger drivers (≤ 20 years, N = 108), aversion to risk taking was still the strongest unique predictor (sr2 = .07). The second analysis confirmed an interaction between gender and aversion to risk taking with males (N = 79) reporting a much weaker relationship between aversion to risk taking and speeding (sr2 = .01). The third analysis showed that drivers who are less frequent drivers (N = 105) also have a weaker relationship between aversion to risk taking and speeding (sr2 = .04). The inclusion of personality variables and coping variables in this study allowed the unique contribution of individuals' aversion to risk-taking to be determined, while the examination of the potential moderating effects of age, gender, and frequency of driving showed that this unique contribution varies between 1% and 7%. Researchers must consider the possible moderating effects of these factors when specifying models that link individual attitudes, perceptions, and attributes to driving behaviours

Giant Beaver Palaeoecology Inferred from Stable Isotopes

This is a multi-individual (n = 11), stable carbon and nitrogen isotope study of bone collagen (δ13Ccol and δ15Ncol) from the giant beaver (genus Castoroides). The now-extinct giant beaver was once one of the most widespread Pleistocene megafauna in North America. We confirm that Castoroides consumed a diet of predominantly submerged aquatic macrophytes. These dietary preferences rendered the giant beaver highly dependent on wetland habitat for survival. Castoroides’ δ13Ccol and δ15Ncol do not support the hypothesis that the giant beaver consumed trees or woody plants, which suggests that it did not share the same behaviours as Castor (i.e., tree-cutting and harvesting). The onset of warmer, more arid conditions likely contributed to the extinction of Castoroides. Six new radiocarbon dates help establish the chronology of the northward dispersal of the giant beaver in Beringia, indicating a correlation with ice sheet retreat

Traceable measurement and imaging of the complex permittivity of a multiphase mineral specimen at micron scales using a microwave microscope

This paper describes traceable measurements of the dielectric permittivity and loss tangent of a multiphase material (particulate rock set in epoxy) at micron scales using a resonant Near-Field Scanning Microwave Microscope (NSMM) at 1.2 GHz. Calibration and extraction of the permittivity and loss tangent is via an image charge analysis which has been modified by the use of the complex frequency to make it applicable for high loss materials. The results presented are obtained using a spherical probe tip, 0.1 mm in diameter, and also a conical probe tip with a rounded end 0.01 mm in diameter, which allows imaging with higher resolution (≈10 µm). The microscope is calibrated using approach-curve data over a restricted range of gaps (typically between 1% and 10% of tip diameter) as this is found to give the best measurement accuracy. For both tips the uncertainty of scanned measurements of permittivity is estimated to be±10% (at coverage factor k=2) for permittivity ⪝10. Loss tangent can be resolved to approximately 0.001. Subject to this limit, the uncertainty of loss tangent measurements is estimated to be±20% (at k=2). The reported measurements inform studies of how microwave energy interacts with multiphase materials containing microwave absorbent phases