Measurement of space charge in the lower atmosphere

A double field mill is described which, when placed at a point abore the earth's surface, is automatically brought to the potential of that point and registers the potential gradient* Two such Instruments are employed to study space charge values In the first fire metres of the atmosphere. Comparison Is made between results obtained using the double mills and an Obolensky-type air filter, which lead to the conclusion that the latter instnuasnt gives incorrect readings in the presence of largp* small- ion concentrations. Space charge studies In fair weather conditions indicate the presence of a negative charge close to the ground of approximately -50µµC/m(^3), decreasing in the first two metres to aero and having an average value between one and three metres of +3µµC/m(^3). file average height to which this charge extends is shown to be proportional to the potential gradient, and has it's origin in ionization produced by radioactive substances in the earth, close to the surface. In disturbed conditions, heavy rain is found to generate a negative space charge of the order of -1000µµC/m(^3) arising from a splashing effect at the earth's surface. In snowfalls charges of +500µµC/m(^3) originate from the charge on the Individual snowflakes and a positive charge left in the air due to rubbing or shattering of the snow as it is falling*The fait weather results in the first metro show a good agreement with those of Norinder, but higher up show the usual positive charge found by Kahler, Daunderer, Scrase, Obolensky and Brown

Primary care-led commissioning and public involvement in the English National Health Service. Lessons from the past.

Background: Patient and Public involvement (PPI) in health care occupies a central place in Western democracies. In England, this theme has been continuously prominent since the introduction of market reforms in the early 1990s. The health care reforms implemented by the current Coalition Government are making primary care practitioners the main commissioners of health care services in the National Health Service, and a duty is placed on them to involve the public in commissioning decisions and strategies. Since implementation of PPI initiatives in primary care commissioning is not new, we asked how likely it is that the new reforms will make a difference. We scanned the main literature related to primary care-led commissioning and found little evidence of effective PPI thus far. We suggest that unless the scope and intended objectives of PPI are clarified and appropriate resources are devoted to it, PPI will continue to remain empty rhetoric and box ticking. Aim: To examine the effect of previous PPI initiatives on health care commissioning and draw lessons for future development. Method: We scanned the literature reporting on previous PPI initiatives in primary careled commissioning since the introduction of the internal market in 1991. In particular, we looked for specific contexts, methods and outcomes of such initiatives. Findings: 1. PPI in commissioning has been constantly encouraged by policy makers in England. 2. Research shows limited evidence of effective methods and outcomes so far. 3. Constant reconfi- guration of health care structures has had a negative impact on PPI. 4. The new structures look hardly better poised to bring about effective public and patient involvement

Shuttle electrical environment

Part of an AFGL payload flown on the STS-4 mission consisted of experiments to measure in-situ electric fields, electron densities, and vehicle charging. During this flight some 11 hours of data were acquired ranging from 5 minute snapshots up to continuous half-orbits. These experiments are described and results presented for such vehicle induced events as a main engine burn, thruster firings and water dumps in addition to undisturbed periods. The main characteristic of all the vehicle induced events is shown to be an enhancement in the low frequency noise (less than 2 kHz), in both the electrostatic and electron irregularity (delta N/N) spectra. The non-event results indicate that the electrostatic broadband emissions show a white noise characteristic in the low frequency range up to 2 kHz at an amplitude of 10 db above the shuttle design specification limit, falling below that limit above 10 kHz. The vehicle potential remained within the range of -3 to +1 volt throughout the flight which exhibits normal behavior for a satellite in a low equatorial orbit

A research note on the benefit of patient and public involvement in research: The experience of prostate cancer patients regarding information in radiotherapy.

This document is the Accepted Manuscript version of the following article: L. Gordon, A. Dickinson, M. Offredy, and J. Smiddy, ‘A research note on the benefit of patient and public involvement in research: The experience of prostate cancer patients regarding information in radiotherapy’, Radiography, Vol. 23(2): 167-170, May 2017, doi: http://dx.doi.org/10.1016/j.radi.2017.02.004. Under embargo. Embargo end date: 27 February 2018. © 2016. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/. © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.Aim To explore the inclusion of patient and public involvement (PPI) in a qualitative study on the experiences of men with prostate cancer regarding information in radiotherapy. Method The application of PPI to one doctoral research study is explored with respect to two perspectives: firstly, involvement of a patient reference group who informed the research design and materials, and secondly, the involvement of a public involvement in research group (PIRg) in advising the researcher during the design process. Discussion PPI is recognised as an important component of contemporary health research. PPI is becoming a common and essential requirement for high quality research projects and yet literature exploring or reporting the involvement and influence of PPI is sparse. Consideration is given to the national PPI landscape that has shaped public involvement in health research. Conclusion The contribution of PPI to this study appears to have been beneficial to the development and evaluation of the study design, the self-worth of the reference group participants and demonstrates that the value of PPI in health research should not be underestimated.Peer reviewe

Baseline and stress-induced levels of corticosterone in male and female Afrotropical and European temperate stonechats during breeding

Background: Latitudinal variation in avian life histories falls along a slow-fast pace of life continuum: tropical species produce small clutches, but have a high survival probability, while in temperate species the opposite pattern is found. This study investigated whether differential investment into reproduction and survival of tropical and temperate species is paralleled by differences in the secretion of the vertebrate hormone corticosterone (CORT). Depending on circulating concentrations, CORT can both act as a metabolic (low to medium levels) and a stress hormone (high levels) and, thereby, influence reproductive decisions. Baseline and stress-induced CORT was measured across sequential stages of the breeding season in males and females of closely related taxa of stonechats (Saxicola spp) from a wide distribution area. We compared stonechats from 13 sites, representing Canary Islands, European temperate and East African tropical areas. Stonechats are highly seasonal breeders at all these sites, but vary between tropical and temperate regions with regard to reproductive investment and presumably also survival. Results: In accordance with life-history theory, during parental stages, post-capture (baseline) CORT was overall lower in tropical than in temperate stonechats. However, during mating stages, tropical males had elevated post-capture (baseline) CORT concentrations, which did not differ from those of temperate males. Female and male mates of a pair showed correlated levels of post-capture CORT when sampled after simulated territorial intrusions. In contrast to the hypothesis that species with low reproduction and high annual survival should be more risk-sensitive, tropical stonechats had lower stress-induced CORT concentrations than temperate stonechats. We also found relatively high post-capture (baseline) and stress-induced CORT concentrations, in slow-paced Canary Islands stonechats. Conclusions: Our data support and refine the view that baseline CORT facilitates energetically demanding activities in males and females and reflects investment into reproduction. Low parental workload was associated with lower post-capture (baseline) CORT as expected for a slow pace of life in tropical species. On a finer resolution, however, this tropical-temperate contrast did not generally hold. Post-capture (baseline) CORT was higher during mating stages in particular in tropical males, possibly to support the energetic needs of mate-guarding. Counter to predictions based on life history theory, our data do not confirm the hypothesis that long-lived tropical populations have higher stress-induced CORT concentrations than short-lived temperate populations. Instead, in the predator-rich tropical environments of African stonechats, a dampened stress response during parental stages may increase survival probabilities of young. Overall our data further support an association between life history and baseline CORT, but challenge the role of stress-induced CORT as a mediator of tropical-temperate variation in life history

Reformation of casein particles from alkaline-disrupted casein micelles

In this study, the properties of casein particles reformed from alkaline disrupted casein micelles were studied. For this purpose, micelles were disrupted completely by increasing milk pH to 10·0, and subsequently reformed by decreasing milk pH to 6·6. Reformed casein particles were smaller than native micelles and had a slightly lower zeta-potential. Levels of ionic and serum calcium, as well as rennet coagulation time did not differ between milk containing native micelles or reformed casein particles. Ethanol stability and heat stability, >pH7·0, were lower for reformed casein particles than native micelles. Differences in heat stability, ethanol stability and zeta-potential can be explained in terms of the influence of increased concentrations of sodium and chloride ions in milk containing reformed casein particles. Hence, these results indicate that, if performed in a controlled manner, casein particles with properties closely similar to those of native micelles can be reformed from alkaline disrupted casein micelle

Fractal-based analysis of optical coherence tomography data to quantify retinal tissue damage

BACKGROUND: The sensitivity of Optical Coherence Tomography (OCT) images to identify retinal tissue morphology characterized by early neural loss from normal healthy eyes is tested by calculating structural information and fractal dimension. OCT data from 74 healthy eyes and 43 eyes with type 1 diabetes mellitus with mild diabetic retinopathy (MDR) on biomicroscopy was analyzed using a custom-built algorithm (OCTRIMA) to measure locally the intraretinal layer thickness. A power spectrum method was used to calculate the fractal dimension in intraretinal regions of interest identified in the images. ANOVA followed by Newman-Keuls post-hoc analyses were used to test for differences between pathological and normal groups. A modified p value of <0.001 was considered statistically significant. Receiver operating characteristic (ROC) curves were constructed to describe the ability of each parameter to discriminate between eyes of pathological patients and normal healthy eyes. RESULTS: Fractal dimension was higher for all the layers (except the GCL + IPL and INL) in MDR eyes compared to normal healthy eyes. When comparing MDR with normal healthy eyes, the highest AUROC values estimated for the fractal dimension were observed for GCL + IPL and INL. The maximum discrimination value for fractal dimension of 0.96 (standard error =0.025) for the GCL + IPL complex was obtained at a FD <= 1.66 (cut off point, asymptotic 95% Confidence Interval: lower-upper bound = 0.905-1.002). Moreover, the highest AUROC values estimated for the thickness measurements were observed for the OPL, GCL + IPL and OS. Particularly, when comparing MDR eyes with control healthy eyes, we found that the fractal dimension of the GCL + IPL complex was significantly better at diagnosing early DR, compared to the standard thickness measurement. CONCLUSIONS: Our results suggest that the GCL + IPL complex, OPL and OS are more susceptible to initial damage when comparing MDR with control healthy eyes. Fractal analysis provided a better sensitivity, offering a potential diagnostic predictor for detecting early neurodegeneration in the retina

Real-Time Automatic Segmentation of Optical Coherence Tomography Volume Data of the Macular Region.

Optical coherence tomography (OCT) is a high speed, high resolution and non-invasive imaging modality that enables the capturing of the 3D structure of the retina. The fast and automatic analysis of 3D volume OCT data is crucial taking into account the increased amount of patient-specific 3D imaging data. In this work, we have developed an automatic algorithm, OCTRIMA 3D (OCT Retinal IMage Analysis 3D), that could segment OCT volume data in the macular region fast and accurately. The proposed method is implemented using the shortest-path based graph search, which detects the retinal boundaries by searching the shortest-path between two end nodes using Dijkstra's algorithm. Additional techniques, such as inter-frame flattening, inter-frame search region refinement, masking and biasing were introduced to exploit the spatial dependency between adjacent frames for the reduction of the processing time. Our segmentation algorithm was evaluated by comparing with the manual labelings and three state of the art graph-based segmentation methods. The processing time for the whole OCT volume of 496x644x51 voxels (captured by Spectralis SD-OCT) was 26.15 seconds which is at least a 2-8-fold increase in speed compared to other, similar reference algorithms used in the comparisons. The average unsigned error was about 1 pixel ( approximately 4 microns), which was also lower compared to the reference algorithms. We believe that OCTRIMA 3D is a leap forward towards achieving reliable, real-time analysis of 3D OCT retinal data

Accuracy of user-adjusted axial length measurements by optical biometry in eyes having combined phacovitrectomy for macular-off rhegmatogenous retinal detachment

PURPOSE: To evaluate the accuracy of user-adjusted axial length measured by optical biometry (OB) for intraocular lens (IOL) power calculations in eyes having combined phacovitrectomy for macula-off rhegmatogenous retinal detachment (RRD). SETTING: Department of Ophthalmology, Calderdale Royal Hospital, Halifax, UK. DESIGN: Prospective Retrospective case series review of 22 consecutive eyes that underwent phacovitrectomy for macula-off RRD. METHODS: Axial lengths (ALs) were measured using OB with user adjustment to identify a posterior peak corresponding to the eye’s AL and ultrasound (US). These measurements were compared and analysed for accuracy to each other and the accurate indication of the eye’s AL. RESULTS: User-adjusted OB was similar to US and post-operative OB measurements. There was no statistically significant difference between the means of the AL measurements derived from user-adjusted OB and ultrasound AL (p=0.964). User-adjusted OB was not statistically significantly different to post-operative OB (p=0.242). Compared to postoperative OB, IOL power was within 0.5 Dioptre in 12 out of 13 cases (92%; 95% confidence interval (77.8%, 100.0%) for user-adjusted OB, and in only 10 out of 13 cases (77%; 95% confidence interval (54.0%, 99.8%) of US measurements. CONCLUSIONS: User-adjusted OB may be used as an alternative method for the measurement of AL in macula-off RRD for primary repair by combined phacovitrectomy. OB will, however, require assessment of agreement with US AL in cases where a posterior peak is not easily identifiable. We have also shown that user-adjusted OB may outperform US AL when calculating IOL power; however, a larger study may be needed to confirm thi

Automated classifiers for early detection and diagnosis of retinopathy in diabetic eyes

BACKGROUND: Artificial neural networks (ANNs) have been used to classify eye diseases, such as diabetic retinopathy (DR) and glaucoma. DR is the leading cause of blindness in working-age adults in the developed world. The implementation of DR diagnostic routines could be feasibly improved by the integration of structural and optical property test measurements of the retinal structure that provide important and complementary information for reaching a diagnosis. In this study, we evaluate the capability of several structural and optical features (thickness, total reflectance and fractal dimension) of various intraretinal layers extracted from optical coherence tomography images to train a Bayesian ANN to discriminate between healthy and diabetic eyes with and with no mild retinopathy. RESULTS: When exploring the probability as to whether the subject's eye was healthy (diagnostic condition, Test 1), we found that the structural and optical property features of the outer plexiform layer (OPL) and the complex formed by the ganglion cell and inner plexiform layers (GCL + IPL) provided the highest probability (positive predictive value (PPV) of 91% and 89%, respectively) for the proportion of patients with positive test results (healthy condition) who were correctly diagnosed (Test 1). The true negative, TP and PPV values remained stable despite the different sizes of training data sets (Test 2). The sensitivity, specificity and PPV were greater or close to 0.70 for the retinal nerve fiber layer's features, photoreceptor outer segments and retinal pigment epithelium when 23 diabetic eyes with mild retinopathy were mixed with 38 diabetic eyes with no retinopathy (Test 3). CONCLUSIONS: A Bayesian ANN trained on structural and optical features from optical coherence tomography data can successfully discriminate between healthy and diabetic eyes with and with no retinopathy. The fractal dimension of the OPL and the GCL + IPL complex predicted by the Bayesian radial basis function network provides better diagnostic utility to classify diabetic eyes with mild retinopathy. Moreover, the thickness and fractal dimension parameters of the retinal nerve fiber layer, photoreceptor outer segments and retinal pigment epithelium show promise for the diagnostic classification between diabetic eyes with and with no mild retinopathy