Reflection of plane waves from the flat boundary of a micropolar elastic halfspace

Microstructure effect on wave propagation, and plane wave reflection from stress free flat surface in micropolar elastic half-spac

Turning around coast-based schools: an interpretive narrative analysis of a report on school reform in English coastal communities

An interpretive narrative inquiry approach is adopted to shed light on the improvement agendas applied in a specific set of coastal schools. The unifying thread between the focal cases is that they had been designated as failures and made notorious through association with their communities’ tainted reputations. These schools feature in a report published by the Future Leaders Trust, which is used as the resource for this paper. The taken for granted deficit discourses implicit in the accounts of how these schools were reformed are relied upon by the school leaders and other stakeholders to justify why they needed to be turned around. These assumptions that come to the fore through analysis, demonstrate that the socioeconomic contexts found in the jaded English coastal communities are not engaged with. Importing approaches that draw on communities’ resistance to relegation could, potentially, build positive discourses that lead to communities reclaiming educational opportunities in such schools, one clear example being that of Countesthorpe in Leicestershire, UK, in the 1970s

Molecular dynamics study of oxygen diffusion in Pr₂NiO_4+δ

Oxygen transport in tetragonal Pr2NiO4+δ has been investigated using molecular dynamics simulations in conjunction with a set of Born model potentials. Oxygen diffusion in Pr2NiO4+δ is highly anisotropic, occurring almost entirely via an interstitialcy mechanism in the a-b plane. The calculated oxygen diffusivity has a weak dependence upon the concentration of oxygen interstitials, in agreement with experimental observations. In the temperature range 800-1500 K, the activation energy for migration varied between 0.49 and 0.64 eV depending upon the degree of hyperstoichiometry. The present results are compared to previous work on oxygen self-diffusion in related K2NiF4 structure materials

Mechanisms of nonstoichiometry in HfN_1-<i>x</i>

Density functional theory is used to calculate defect structures that can accommodate nonstoichiometry in hafnium nitride: HfN1-x, 0 ≤ X ≤ 0.25. It is predicted that a mechanism assuming simple distributions of nitrogen vacancies can accurately describe the variation in the experimentally observed lattice parameter with respect to the nitrogen nonstoichiometry. Although the lattice parameter changes are remarkably small across the whole nonstoichiometry range, the variations in the bulk modulus are much greater

Anisotropic oxygen diffusion in tetragonal La₂NiO_4+δ: molecular dynamics calculations

Molecular dynamics simulations, used in conjunction with a set of Born model potentials, have been employed to study oxygen transport in tetragonal La2NiO4+δ. We predict an interstitialcy mechanism with an activation energy of migration of 0.51 eV in the temperature range 800-1100 K. The simulations are consistent with the most recent experiments. The prevalence of oxygen diffusion in the a-b plane accounts for the anisotropy observed in measurements of diffusivity in tetragonal La2NiO4+δ

Influence of surgery and rehabilitation conditioning on psychophysiological fitness

The purpose of this study was to assess changes in psychophysiological fitness following reconstructive knee surgery and early phase (2.5 months) physical rehabilitation. Nine patients (7 male, 2 female; mean age, 29.9 years) electing to undergo anterior cruciate ligament reconstructive surgery (central third, bone-patella tendon-bone graft) were assessed on four separate assessment occasions post-surgery. Repeated measures ANOVAs showed significant condition (injured/non-injured leg) by test occasion (2 weeks pre-surgery and 6, 8 and 10 weeks post-surgery) interactions for knee ligamentous compliance (anterior tibiofemoral displacement), peak force and electromechanical delay associated with the knee flexors of the injured and noninjured legs (F3,24 = 4.7 to 6.6; p < 0.01), together with individualized emotional profile disturbance scores that were significantly less at 10 weeks post-surgery compared to pre-surgery, 6 weeks and 8 weeks post-surgery (F3,24 = 7.6; p < 0.01). Spearman rank correlation coefficients identified significant relationships between musculoskeletal fitness and emotional profile scores at pre-surgery (r = 0.69–0.72; p < 0.05) and at 8 weeks post-surgery (r = 0.70–0.73; p < 0.05). The 6 Bi-POMS subscales and the 12 ERAIQ responses found inconsistent patterns of response and relationships across the assessment occasions. Overall, the patterning of changes and associations amongst emotional performance profile discrepancy scores in conjunction with those scores from indices of musculoskeletal fitness performance capability offered important support for the efficacy of an approach which integrates self-perceptive and objective measurements of fitness capability during rehabilitation following surgery to a synovial joint

A Middle Pleistocene Butchery Site at Great Yeldham, Essex, UK: Identifying Butchery Strategies and Implications for Mammalian Faunal History

This paper discusses the evidence relating to an assemblage of Pleistocene bones and teeth discovered in a brick pit at Great Yeldham, Essex, in the late nineteenth century. Surviving elements from this collection, which include a bison foot bone with cut-marks, are now in the British Geological Survey Museum, Keyworth. A re-examination of this collection suggests that humans were present at the site during a temperate period in the earlier part of the late Middle Pleistocene. The cut-marks suggest that the hind foot was detached and discarded as butchery waste at the death site. Finally, the paper discusses the implications of humanly modified bones for understanding aspects of early human behaviour and distribution in Britain, which have hitherto largely centred around the study of stone tools

Refractory Hypercalcemia in Sarcoidosis: Exacerbation by thiazide diuretics, differentiation from primary hyperparathyroidism, and possible role of prolactin

Hypercalcemia in a patient with sarcoidosis was made worse by a thiazide diuretic initially given to control hypercalciuria alone. The hypercalcemia was unusually resistant to corticosteroid treatment during the summer even after the thiazide diuretic had been discontinued. Lack of response to corticosteroid together with decreased tubular reabsorption of phosphate and increased tubular reabsorption of calcium suggested associated primary hyperparathyroidism, but PTH was undetectable by immunoassay, and nephrogenous cyclic AMP excretion was zero. Amenorrhea, galactorrhea and hyperprolactinemia were found to be due to a pituitary tumor which was removed. The experience with this patient suggests that: 1) exacerbation of hypercalcemia by thiazides does not discriminate between its different causes; 2) finding low values for plasma parathyroid homone (PTH) and nephrogenous cyclic AMP is the most certain way of excluding primary hyperparathyroidism in patients with hypercalcemia from other causes; 3) prolactin excess, by increasing the synthesis of 1,25 dihydroxycholecalciferol, may have intensified the calcium metabolism disorder

The origins of radial fracture systems and associated large lava flows on Venus

Magellan images have revealed the existence of systems of radial fractures on venus that are very similar in form to terrestrial dike swarms such as the Mackenzie swarm in Northern Canada. The association of many of the fracture systems with lava flows, calderas, and volcanic edifices further support the idea of a dike emplacement origin. A global survey of the Magellan images has allowed the location of 300 such fracture systems. Two types of fracture systems are defined. A series of models were developed to simulate the emplacement of dikes on Venus. Observations of fracture lengths and widths were then used to constrain the emplacement conditions. The model results show that the great length and relatively large width of the fractures can only be explained if the dikes that produce them were emplaced in high driving pressure (pressure buffered) conditions. Such conditions imply high rates of melt production, which is consistent with the melt being derived directly from a plume head. We have recently modeled the vertical emplacement of a dike from the top of a mantle plume and calculated the eruption rates such a dike would produce on reaching the surface. This modeling shows that eruption rates of approximately 0.1 cu km/hr can readily be generated by such a dike, consistent with the above results. However, the sensitivity of the model to dike width and therefore driving pressure means that eruption rates from dikes emplaced from the base of the crust or the head of a mantle plume could be orders of magnitude higher than this. Clearly, therefore, the model needs to be refined in order to better constrain eruption conditions. However, it is worth noting here that the initial results do show that even for moderate dike widths, eruption rates could be at least on the order of those estimated for terrestrial flood basalts

Use of shallow samples to estimate the total carbon storage in pastoral soils

Using data from pastoral soils sampled by horizon at 56 locations across New Zealand, we conducted a meta-analysis. On average, the total depth sampled was 0.93 ± 0.026 m (± SEM), and on a volumetric basis, the total C storage averaged 26.9 ± 1.8, 13.9 ± 0.6 and 9.2 ± 1.4 kg C m⁻² for allophanic (n=12), non-allophanic (n=40) and pumice soils (n=4), respectively. We estimated the total C storage, and quantified the uncertainty, using the data for samples taken from the uppermost A-horizon whose depth averaged 0.1 ± 0.003 m. For A-horizon samples of the allophanic soils, the mean C content was 108 ± 6 g C kg⁻¹ and the bulk density was 772 ± 29 kg m⁻³, for non-allophanic soils they were 51 ± 4 g C kg⁻¹ and 1055 ± 29 kg m⁻³, and for pumice soils they were 68 ± 9 g C kg⁻¹ and 715 ± 45 kg m⁻³. The C density —a product of the C content and bulk density —of the A-horizon samples was proportional to their air-dried water content, a proxy measure for the mineral surface area. By linear regression with C density of the A-horizon, the total C storage could be estimated with a standard error of 3.1 kg C m⁻², 19% of the overall mean