Managing the acidity of abandoned water filled coal mining voids in Collie (Western Australia) using organic matter

The effectiveness of using organic matter additions to increase pH in abandoned water filled coal mining voids in Collie was investigated. Previous studies have demonstrated that passing acidic drainage through organic matter increased the waters pH. Laboratory trials using intact sediment cores (collected from Ewington, Collie, Western Australia) were used to assess the effects of additions of hay, manure and mulched vegetation on pH, nutrients an sulphate levels. In a series of experiments the effect of different quantities of organic material, sulphate reducing bacterial inoculations and alkalinity generation were measured. A subsequent field experiment was conducted to examine the impact that manure and mulch had on mine void water in 18 in situ ponds constructed adjacent to Ewington. It was concluded from the laboratory experiments that mulch and manure treatments were significantly better than hay as an organic matter addition for increasing the pH of acidified mine void water at Ewington. The manure produced the greatest increase in pH, although it contributed less to alkalinity than mulch; suggesting mulch bas a greater ability to release carbonates than did manure. The manure and mulch additions increased the pH in the laboratory and field experiment by 0.5-1.5 pH units. This increase was sustained for most of the 21 week field experiment. An increase in pH in the control ponds was recorded over the last 8 weeks of the experiment which was probably due to the inflow of more alkaline groundwater through the substratum as a consequence of the winter rainfall. pH values measured in the experimental ponds 15 months after the commencement of the project indicated that the ponds treated with manure maintained significantly higher pH levels than either the mulch or the control ponds. There was no difference between the pH values for the ponds treated with mulch and the controls suggesting that manure not only provided a greater increase in pH but also over a longer period. The addition of organic mailer also resulted in an increase in gilvin in the laboratory experiments. Low sulphate and sulphide levels were also recorded in all experiments before and after the introduction of organic materials into mine void water and ponds adjacent to Ewington indicating that sulphate reducing bacterial activity was not the cause for the increase in pH as occurred in other situations, but rather the addition of alkaline organic matter caused the increase in pH. The addition of manure organic material was associated with an increase in the ortho-phosphate levels, resulting in an increase in chlorophyll a concentrations. It is believed to be the first stages of succession processes leading to the establishment of a biologically active wetland system. During this process the emerging ecosystem neutralises the acidic content of the water

Surface pressure distributions on a delta wing undergoing large amplitude pitching oscillations

Wind tunnel experiments were performed on a 70 deg sweep delta wing to determine the effect of a sinusoidal pitching motion on the pressure field on the suction side of the wing. Twelve pressure taps were placed from 35 to 90 percent of the chord, at 60 percent of the local semi-span. Pressure coefficients were measured as a function of Reynolds number and pitch rate. The pressure coefficient was seen to vary at approximately the same frequency as the pitching frequency. The relative pressure variation at each chord location was comparable for each case. The average pressure distribution through each periodic motion was near the static distribution for the average angle of attack. Upon comparing the upstroke and downstroke pressures for a specific angle of attack, the downstroke pressures were slightly larger. Vortex breakdown was seen to have the most significant effect at the 40 to 45 percent chord location, where a decrease in pressure was apparent

Characterisation of sensitivity and orientation tuning for visually responsive ensembles in the zebrafish tectum

Sensory coding relies on ensembles of co-active neurons, but these ensembles change from trial to trial of the same stimulus. This is due in part to wide variability in the responsiveness of neurons within these ensembles, with some neurons responding regularly to a stimulus while others respond inconsistently. The specific functional properties that cause neurons to respond more or less consistently have not been thoroughly explored. Here, we have examined neuronal ensembles in the zebrafish tectum responsive to repeated presentations of a visual stimulus, and have explored how these populations change when the orientation or brightness of the stimulus is altered. We found a continuum of response probabilities across the neurons in the visual ensembles, with the most responsive neurons focused toward the spatial centre of the ensemble. As the visual stimulus was made dimmer, these neurons remained active, suggesting higher overall responsiveness. However, these cells appeared to represent the most consistent end of a continuum, rather than a functionally distinct "core" of highly responsive neurons. Reliably responsive cells were broadly tuned to a range of stimulus orientations suggesting that, at least for this stimulus property, tight stimulus tuning was not responsible for their consistent responses

Pure and loaded fireballs in SGR giant flares

On December 27, 2004, a giant flare from SGR 1806$-$20 was detected on earth. Its thermal spectrum and temperature suggest that the flare resulted from an energy release of about $10^{47}$ erg/sec close to the surface of a neutron star in the form of radiation and/or pairs. This plasma expanded under its own pressure producing a fireball and the observed gamma-rays escaped once the fireball became optically thin. The giant flare was followed by a bright radio afterglow, with an observable extended size, implying an energetic relativistic outflow. We revisit here the evolution of relativistic fireballs and we calculate the Lorentz factor and energy remaining in relativistic outflow once the radiation escapes. We show that pairs that arise naturally in a pure pairs-radiation fireball do not carry enough energy to account for the observed afterglow. We consider various alternatives and we show that if the relativistic outflow that causes the afterglow is related directly to the prompt flare, then the initial fireball must be loaded by baryons or Poynting flux. While we focus on parameters applicable to the giant flare and the radio afterglow of SGR 1806$-$20 the calculations presented here might be also applicable to GRBs

Using Game of Thrones to teach neuroscience and neuropharmacology during lockdown

Peer reviewedPublisher PD

Experiential learning, new venture creation, strategic entrepreneurship, knowledge and competency in the university context

In this paper, by analysing two different entrepreneurship education programmes in the UK, we explore how experiential entrepreneurial learning can be optimised while students engage in parallel in actually creating a new venture. Until both programmes are properly up-and running - with graduates – both programmes started in 2009 - it will not be possible to draw firm conclusions about the types of business being started. This paper describes how research, experience and anecdotal evidence was used to develop two degrees. Progress will be the subject of reflective, longitudinal research to evaluate the relevant propositions. We identified four important issues arising from our analysis. First, a clear importance within these programmes that students start a real business, rather than just learn with cases or participate in simulations, business games, or role plays. In addition, we see a need to capture the learning with a portfolio. Second, there remains a debate about whether such a pedagogical intervention is best achieved at Undergraduate (Bachelor’s) or Postgraduate (Master’s) level. However, an important point about these programmes is that students can still graduate because there is a valuable learning experience in business start up to capture in a portfolio. Third, it remains unclear whether entrepreneurship (as opposed to enterprise skills) should be in the curriculum or adjunct to it. Or, indeed, whether the optimal situation is to have entrepreneurship as both part of the curriculum and adjunct to it. Fourth, it is important to recognise the potential of collaboration between 'complementary' Universities and the building of a sharing community, something of a federation which might grow over time, grounded with reference to entrepreneurial universities

An adaptable method using human mixed tissue ratiometric controls for benchmarking performance on gene expression microarrays in clinical laboratories

<p>Abstract</p> <p>Background</p> <p>Molecular biomarkers that are based on mRNA transcripts are being developed for the diagnosis and treatment of a number of diseases. DNA microarrays are one of the primary technologies being used to develop classifiers from gene expression data for clinically relevant outcomes. Microarray assays are highly multiplexed measures of comparative gene expression but have a limited dynamic range of measurement and show compression in fold change detection. To increase the clinical utility of microarrays, assay controls are needed that benchmark performance using metrics that are relevant to the analysis of genomic data generated with biological samples.</p> <p>Results</p> <p>Ratiometric controls were prepared from commercial sources of high quality RNA from human tissues with distinctly different expression profiles and mixed in defined ratios. The samples were processed using six different target labeling protocols and replicate datasets were generated on high density gene expression microarrays. The area under the curve from receiver operating characteristic plots was calculated to measure diagnostic performance. The reliable region of the dynamic range was derived from log₂ratio deviation plots made for each dataset. Small but statistically significant differences in diagnostic performance were observed between standardized assays available from the array manufacturer and alternative methods for target generation. Assay performance using the reliable range of comparative measurement as a metric was improved by adjusting sample hybridization conditions for one commercial kit.</p> <p>Conclusions</p> <p>Process improvement in microarray assay performance was demonstrated using samples prepared from commercially available materials and two metrics - diagnostic performance and the reliable range of measurement. These methods have advantages over approaches that use a limited set of external controls or correlations to reference sets, because they provide benchmark values that can be used by clinical laboratories to help optimize protocol conditions and laboratory proficiency with microarray assays.</p

Cerebral Amyloid and Hypertension are Independently Associated with White Matter Lesions in Elderly.

In cognitively normal (CN) elderly individuals, white matter hyperintensities (WMH) are commonly viewed as a marker of cerebral small vessel disease (SVD). SVD is due to exposure to systemic vascular injury processes associated with highly prevalent vascular risk factors (VRFs) such as hypertension, high cholesterol, and diabetes. However, cerebral amyloid accumulation is also prevalent in this population and is associated with WMH accrual. Therefore, we examined the independent associations of amyloid burden and VRFs with WMH burden in CN elderly individuals with low to moderate vascular risk. Participants (n = 150) in the Alzheimer's Disease Neuroimaging Initiative (ADNI) received fluid attenuated inversion recovery (FLAIR) MRI at study entry. Total WMH volume was calculated from FLAIR images co-registered with structural MRI. Amyloid burden was determined by cerebrospinal fluid Aβ1-42 levels. Clinical histories of VRFs, as well as current measurements of vascular status, were recorded during a baseline clinical evaluation. We tested ridge regression models for independent associations and interactions of elevated blood pressure (BP) and amyloid to total WMH volume. We found that greater amyloid burden and a clinical history of hypertension were independently associated with greater WMH volume. In addition, elevated BP modified the association between amyloid and WMH, such that those with either current or past evidence of elevated BP had greater WMH volumes at a given burden of amyloid. These findings are consistent with the hypothesis that cerebral amyloid accumulation and VRFs are independently associated with clinically latent white matter damage represented by WMHs. The potential contribution of amyloid to WMHs should be further explored, even among elderly individuals without cognitive impairment and with limited VRF exposure

Superconductivity in SrNi2As2 Single Crystals

The electrical resistivity \rho(T) and heat capacity C(T) on single crystals of SrNi2As2 and EuNi2As2 are reported. While there is no evidence for a structural transition in either compound, SrNi2As2 is found to be a bulk superconductor at T_c=0.62 K with a Sommerfeld coefficient of \gamma= 8.7 mJ/mol K^2 and a small upper critical field H_{c2} \sim 200 Oe. No superconductivity was found in EuNi2As2 above 0.4 K, but anomalies in \rho and C reveal that magnetic order associated with the Eu^{2+} magnetic moments occurs at T_m = 14 K.Comment: 8 pages, 5 figure