The Western Irish Namurian Basin reassessed

Current basin models for the Western Irish Namurian Basin (WINB) envisage an elongate trough along the line of the present-day Shannon Estuary that was infilled with clastic sediments derived from a hinterland that lay to the W or NW. This paper argues for an alternative basin configuration with source areas to the SW supplying sediment to a basin where deepest water conditions were in northern County Clare. Rapid subsidence along the present-day Shannon Estuary ponded sediment in this area throughout the early Namurian and, only with the rapid increase of sedimentation rates within the mid-Namurian (Kinderscoutian Stage), were substantial amounts of sediment able to prograde to the NE of the basin. This alternative model better explains the overwhelming predominance of NE-directed palaeocurrents in the Namurian infill, but requires fundamental revisions to most aspects of current depositional models. Deep-water black shales (Clare Shale Formation) initially accumulated throughout the region and were progressively downlapped by an unconfined turbidite system (Ross Formation) prograding to the NE. This in turn was succeeded by an unstable, siltstone-dominated slope system (Gull Island Formation) characterized by large-scale soft-sediment deformation, which also prograded to the NE. In the northern-most basin outcrops, in northern County Clare, this early phase of basin infill was developed as a condensed succession of radiolarian-rich black shales, minor turbiditic sandstones and undisturbed siltstones. The new basin model envisages the northern exposures of County Clare to be a distal, basin floor succession whereas the traditional model considers it a relatively shallow, winnowed, basin margin succession. Later stages of basin infill consist of a series of deltaic cycles that culminate in major, erosive-based sandstone bodies (e.g. Tullig Sandstone) interpreted either as axial, deltaic feeder channels or incised valley fills genetically unrelated to the underlying deltaic facies. Within the context of the new basin model the former alternative is most likely and estimated channel depths within the Tullig Sandstone indicate that the basal erosive surface could have been generated by intrinsic fluvial scour without recourse to base-level fall. The northerly flowing Tullig channels pass down-dip into isolated channel sandbodies interbedded with wave-dominated strata that suggest the deltas of the WINB were considerably more wave-influenced than hitherto proposed. The retreat of the Tullig delta during sea-level rise saw the rapid southerly retrogradation of parasequences, as may be expected if the basin margin lay to the SW of the present-day outcrops

Coherent flow structures in a depth-limited flow over a gravel surface : the role of near-bed turbulance and influence of Reynolds number

In gravel bed rivers, the microtopography of the bed exerts a significant effect on the generation of turbulent flow structures. Although field and laboratory measurements have indicated that flows over gravel beds contain coherent macroturbulent flow structures, the origin of these phenomena, and their relationship to the ensemble of individual roughness elements forming the bed, is not quantitatively well understood. Here we report upon a flume experiment in which flow over a gravel surface is quantified through the application of digital particle imaging velocimetry, which allows study of the downstream and vertical components of velocity over the entire flow field. The results indicate that as the Reynolds number increases (1) the visual distinctiveness of the coherent flow structures becomes more defined, (2) the upstream slope of the structures increases, and (3) the turbulence intensity of the structures increases. Analysis of the mean velocity components, the turbulence intensity, and the flow structure using quadrant analysis demonstrates that these large-scale turbulent structures originate from flow interactions with the bed topography. Detection of the dominant temporal length scales through wavelet analysis enables calculation of mean separation zone lengths associated with the gravel roughness through standard scaling laws. The calculated separation zone lengths demonstrate that wake flapping is a dominant mechanism in the production of large-scale coherent flow structures in gravel bed rivers. Thus, we show that coherent flow structures over gravels owe their origin to bed-generated turbulence and that large-scale outer layer structures are the result of flow-topography interactions in the near-bed region associated with wake flapping

Earth observation tool for monitoring coastal eutrophication

ISECA is an Interreg project running until September 2014 that aims to advance and disseminate scientific knowledge related to eutrophication in the 2Seas area (English Channel and North Sea).The main objective of ISECA is to develop a demonstration prototype of an information system for monitoring eutrophication of coastal waters.This information system combines in-situ, satellite information and models outputs

Effects of Methylene Blue and Polyethelene Glycol on Facial Nerve Axotomy Recovery

poster abstractInjury and disease are common factors affecting peripheral nerves and can lead to loss of function. Recovery time after an injury is slow and not very efficient in humans. Treatment methods involving methylene blue (MB) and polyethylene glycol (PEG) have shown combinational effects in sciatic nerve axotomies. We are using behavior analysis of eye blink reflex and vibrissae orientation and movement as a measurement of rate of functional recovery. We will have treatment groups of both cut and crush rats. For each group we will be testing the effect of PEG/MB or no treatment control groups. The results of these treatment groups are significant to finding treatment options for clinical use

Exploring the relationship between hydrograph characteristics and the time evolution of sand bed morphology

The development of sand bed morphology in response to steady uniform flow is well described by phase diagrams. This includes the predications of bedform spacing, and individual bedform characteristics, both important parameters on describing flow resistance. However during time varying flow such as that experienced during the passage of a flood wave, the implicit assumption that bed form adjustment tracks changes to flow does not hold true with evidence of bed form hysteresis in flood cycles. Consequently there is a need to understand which characteristics of unsteady flow drive the disequilibrium between bedform geometries and the hydraulic conditions. This paper describes a series of experiments set up to identify the impacts of hydrograph characteristics on the morphodynamic evolution of alluvial dunes. A series of mobile bed experiments were undertaken in a 16m long, 1.6m wide flume, using a uniform sediment of medium sand (D50 of 450μm). Sediment was water worked under steady flow until quasi equilibrium bed conditions were met whereupon a hydrograph consisting of a rising and falling rising limb was applied. At the end of the hydrograph a period of steady flow was once again run until equilibrium conditions were attained. During the experiments profiles of bed morphology were measured continuously along a 5m long, 0.6m wide transect taken along the channel centreline using ultrasonic sensors. Flow was measured with a suite of Acoustic Doppler Velocimeters and suspended sediment with Acoustic Backscatter Sensors. Results are reported for two different hydrographs applied to two different initial starting conditions. The impact of the differing rising-limb characteristics are discussed in terms of differences between equilibrium bed morphologies, flow field characteristics and suspended sediment concentrations

Identification of baryon resonances in central heavy-ion collisions at energies between 1 and 2 AGeV

The mass distributions of baryon resonances populated in near-central collisions of Au on Au and Ni on Ni are deduced by defolding the $p_t$ spectra of charged pions by a method which does not depend on a specific resonance shape. In addition the mass distributions of resonances are obtained from the invariant masses of $(p, \pi^{\pm})$ pairs. With both methods the deduced mass distributions are shifted by an average value of -60 MeV/c$^2$ relative to the mass distribution of the free $\Delta(1232)$ resonance, the distributions descent almost exponentially towards mass values of 2000 MeV/c^2. The observed differences between $(p, \pi^-)$ and $(p, \pi^+)$ pairs indicate a contribution of isospin $I = 1/2$ resonances. The attempt to consistently describe the deduced mass distributions and the reconstructed kinetic energy spectra of the resonances leads to new insights about the freeze out conditions, i.e. to rather low temperatures and large expansion velocities.Comment: 30 pages, 13 figures, Latex using documentstyle[12pt,a4,epsfig], to appear in Eur. Phys. J.

Exploring Appropriation of Global Cultural Rituals

Adolescents, as a consequence of identification with popular culture, have been described as having homogenous consumption patterns. More recently, however, it has been recognised that ‘glocalisation’ (global practices reworked to fit local contexts) affords an opportunity for differentiation. This paper considers a recent UK phenomenon, namely that of the US high school prom, and seeks to explore the ways in which this ritual has been adopted or adapted as part of youth culture. The method employed here was mixed methods and included in-depth interviews with those who attended a prom in the last three years as well as a questionnaire distributed amongst high school pupils who were anticipating a high school prom. The findings illustrate that the high school prom in the UK is becoming increasingly integrated into the fabric of youth culture although, depending on the agentic abilities employed by the emerging adults in the sample, there is differing appropriation of this ritual event particularly in relation to attitudes towards and motivations for attending the prom. A typology of prom attendees is posited. This paper contributes to our understanding of this practice in a local context