3,021 research outputs found
Lost on re-entry: the Columbia disaster
No full textThe NASA Space shuttle must be the most sophisticated engineering
accomplishment of humankind. The catastrophic loss of Columbia and crew at reentry
early this year was totally unexpected and a blow to manned space
exploration. DIRK PONS looks into the final moments of Columbia
Differentiation of Matter and Antimatter by Hand: Internal and External Structures of the Electron and Antielectron
Get PDFA previous conceptual work, called the Cordus conjecture, has proposed a non-local hidden-variable (NLHV) design for the photon, and thereby proposed a solution to photon entanglement and wave-particle duality. This paper applies a systems design approach to extend the theory to matter, specifically to differentiate between the matter-antimatter species. This concept rests on two premises: that particules have span (physical separation between reactive ends); and that their externally emitted discrete forces have an energisation sequence. Specific hidden-variable models are proposed for the electron, positron, and proton. This concept provides a better explanation of the difference between matter and antimatter in ways that make physical sense. It also provides foundational concepts from which new solutions to other problems, like annihilation and baryogenesis, can be envisaged. The Cordus theory goes beyond conventional NLHV solutions, such as the de Broglie-Bohm model, by offering a solution not only for the inner contents of a particle, the hidden variables, but also predicting how its discrete fields operate. This theory provides a physically natural explanation for spin, handedness, chirality, and related directional attributes of particles, which are otherwise only abstract concepts in quantum mechanics. The theory also explains parity violation, and why the photon does not have an antiparticle. This work makes a conceptual contribution of presenting a new concept of handedness and the matter-antimatter species differentiation. It demonstrates the potential of hidden-variable designs to provide solutions of high explanatory power
Rapporteur’s report – innovative geotechnologies for energy transition
No full textThe 9th Society for Underwater Technology (SUT) International Conference on Offshore Site Investigation and Geotechnics (OSIG) closed with a Rapporteur’s report given by the author. This paper provides a record of that report, transcribed from a video recording. The presentation slides are shown as Figures.</p
DEFRApH - Sample collection and handling procedures
Get PDFAll chemical and biogeochemical process in the sea are affected by the acidity of the water. Acidity is therefore fundamental property of seawater. The growing concern that the acidity of the oceans might be increasing has revealed weaknesses in our knowledge of this fundamental property and its variation in space and time. In 2008 the DEFRApH project (DEFRA contract ME4133) was initiated to provide this missing information in UK related waters. It required sampling for and analysis of the total inorganic carbon and total alkalinity content of samples. This reports documents the procedures sued for sampling. A companion document Hartman Dumousseaud and Roberts (NOC Internal Document No. 01) describes in detail the analytical procedures used and the calculation of the results
Author Correction:Prefrontal cortical ChAT-VIP interneurons provide local excitation by cholinergic synaptic transmission and control attention (Nature Communications, (2019), 10, 1, (5280), 10.1038/s41467-019-13244-9)
No full textThe original version of this Article contained an error in the spelling of the author Wilma D.J. van de Berg, which was incorrectly given as Wilma D.J. van den Berg. This has now been corrected in both the PDF and HTML versions of the Article.</p
Sunitinib treatment exacerbates intratumoral heterogeneity in metastatic renal cancer
No full textThis work was supported by the Chief Scientist Office, Scotland (ETM37; to G.D. Stewart, A.C.P. Riddick, M. Aitchison, and D.J. Harrison), Cancer Research UK (Experimental Cancer Medicine Centre; to T. Powles, London and D.J. Harrison, Edinburgh), Medical Research Council (to A. Laird and D.J. Harrison), Royal College of Surgeons of Edinburgh (to A. Laird), Melville Trust (to A. Laird), Medical Research Council (MC_UU_12018/25; to I.M. Overton), Royal Society of Edinburgh Scottish Government Fellowship cofunded by Marie Curie Actions (to I.M. Overton), Renal Cancer Research Fund (to G.D. Stewart), Kidney Cancer Scotland (to G.D. Stewart) and an educational grant from Pfizer (to T. Powles).Purpose: The aim of this study was to investigate the effect of VEGF targeted therapy (sunitinib) on molecular intratumoral heterogeneity (ITH) in metastatic clear cell renal cancer (mccRCC). Experimental design: Multiple tumor samples (n=187 samples) were taken from the primary renal tumors of mccRCC patients who were sunitinib treated (n=23, SuMR clinical trial) or untreated (n=23, SCOTRRCC study). ITH of pathological grade, DNA (aCGH), mRNA (Illumina Beadarray) and candidate proteins (reverse phase protein array) were evaluated using unsupervised and supervised analyses (driver mutations, hypoxia and stromal related genes). ITH was analysed using intratumoral protein variance distributions and distribution of individual patient aCGH and gene expression clustering. Results: Tumor grade heterogeneity was greater in treated compared to untreated tumors (P=0.002). In unsupervised analysis, sunitinib therapy was not associated with increased ITH in DNA or mRNA. However, there was an increase in ITH for the driver mutation gene signature (DNA and mRNA) as well as increasing variability of protein expression with treatment (p<0.05). Despite this variability, significant chromosomal and transcript changes to key targets of sunitinib, such as VHL, PBRM1 and CAIX, occurred in the treated samples. Conclusions: These findings suggest that sunitinib treatment has significant effects on the expression and ITH of key tumor and treatment specific genes/proteins in mccRCC. The results, based on primary tumor analysis, do not support the hypothesis that resistant clones are selected and predominate following targeted therapy.Peer reviewe
Can target-to-pons ratio be used as a reliable method for the analysis of [ 11C]PIB brain scans?
No full textRationale: 11C]PIB is the most widely used PET imaging marker for amyloid in dementia studies. In the majority of studies the cerebellum has been used as a reference region. However, cerebellar amyloid may be present in genetic Alzheimer's (AD), cerebral amyloid angiopathy and prion diseases. Therefore, we investigated whether the pons could be used as an alternative reference region for the analysis of [ 11C]PIB binding in AD. The aims of the study were to: 1) Evaluate the pons as a reference region using arterial plasma input function and Logan graphical analysis of binding. 2) Assess the power of target-to-pons ratios to discriminate controls from AD subjects. 3) Determine the test-retest reliability in AD subjects. 4) Demonstrate the application of target-to-pons ratio in subjects with elevated cerebellar [ 11C]PIB binding. Methods: 12 sporadic AD subjects aged 65±4.5yrs with a mean MMSE 21.4±4 and 10 age-matched control subjects had [ 11C]PIB PET with arterial blood sampling. Three additional subjects (two subjects with pre-symptomatic presenilin-1 mutation carriers and one probable familial AD) were also studied. Object maps were created by segmenting individual MRIs and spatially transforming the gray matter images into standard stereotaxic MNI space and then superimposing a probabilistic atlas. Cortical [ 11C]PIB binding was assessed with an ROI (region of interest) analysis. Parametric maps of the volume of distribution (V T) were generated with Logan analysis. Additionally, parametric maps of the 60-90min target-to-cerebellar ratio (RATIO CER) and the 60-90min target-to-pons ratio (RATIO PONS) were computed. Results: All three approaches were able to differentiate AD from controls (p0.83); RATIO CER performed best closely followed by RATIO PONS. The two subjects with presenilin-1 mutations and the probable familial AD case showed no significant differences in cortical binding using RATIO CER, but the RATIO PONS approach revealed higher [ 11C]PIB binding in cortex and cerebellum. Conclusion: This study established 60-90min target-to-pons RATIOs as a reliable method of analysis in [ 11C]PIB PET studies where cerebellum is not an appropriate reference region. © 2012 Elsevier Inc
Automated midbrain-pons ratio using artificial intelligence differentiates PSP from other atypical parkinsonian disorders
No full textObjective: Our primary goal was to implement an automated measure of the midbrain to pons ratio (MPR) using an artificial intelligence method. Our second objective was to assess the diagnostic accuracy of the MPR for PSP against a range of parkinsonian disorders.Background: There is a high degree of clinical overlap between atypical parkinsonian disorders, there is a high degree of clinical overlap, particularly in early disease. PSP is an atypical parkinsonian syndrome causing rapidly progressive neurodegenerative disease with motor and cognitive impairment.The MPR is a recognised and partially validated imaging biomarker for the disease. It has not been assessed in differentiating PSP from other atypical parkinsonian disorders.Currently, MPR requires manual assessment by an expert familiar with neuroimaging. Automating it would facilitate large scale analysis for use as a diagnostic biomarker for clinical use and in trials.Method: Our deep reinforcement learning method, communicative multi-agent reinforcement learning (C-MARL), trains agents to find landmarks. Agents explore 3D volumes and are rewarded based on their distance to the target landmark. They learn to communicate to increase their accuracy.We used data from 370 participants (HCN=131, CBS=80, PSP=134, MSA=25 MSA) from the Cambridge Centre for Parkinsons Plus Disorders and the PROSPECT-M data split in training, testing and validation sets (70:15:15). Four landmarks from the midbrain and pons were manually recorded, using Massey et al.’s annotation method [1].ROC analysis was carried out to assess the efficacy of the MPR in discriminating PSP from other APS.Results: The algorithm was accurate in identifying landmarks (mean error 0.8mm, SD 0.3mm), resulting in an accurate measurement of MPR (mean percent error 3.7, SD 1.7).The MPR was significantly smaller in PSP patients in comparison to all other groups [Figure 1], with a high accuracy for distinguishing between groups (AUC values: HC0.98, MSA 0.97, CBD 0.90).Conclusion: We report a new highly accurate automated measure of MPR predictor using artificial intelligence. We demonstrate that the MPR is a useful diagnostic biomarker for distinguishing PSP from other atypical parkinsonian disorders.References: [1] Massey, L.A., Jäger, H.R., Paviour, D.C., O’Sullivan, S.S., Ling, H., Williams, D.R., Kallis, C., Holton, J., Revesz, T., Burn, D.J. and Yousry, T., 2013. The midbrain to pons ratio: a simple and specific MRI sign of progressive supranuclear palsy. Neurology, 80(20), pp.1856-1861.</p
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Automated midbrain-pons ratio using artificial intelligence differentiates PSP from other atypical parkinsonian disorders
No full textObjective: Our primary goal was to implement an automated measure of the midbrain to pons ratio (MPR) using an artificial intelligence method. Our second objective was to assess the diagnostic accuracy of the MPR for PSP against a range of parkinsonian disorders.Background: There is a high degree of clinical overlap between atypical parkinsonian disorders, there is a high degree of clinical overlap, particularly in early disease. PSP is an atypical parkinsonian syndrome causing rapidly progressive neurodegenerative disease with motor and cognitive impairment.The MPR is a recognised and partially validated imaging biomarker for the disease. It has not been assessed in differentiating PSP from other atypical parkinsonian disorders.Currently, MPR requires manual assessment by an expert familiar with neuroimaging. Automating it would facilitate large scale analysis for use as a diagnostic biomarker for clinical use and in trials.Method: Our deep reinforcement learning method, communicative multi-agent reinforcement learning (C-MARL), trains agents to find landmarks. Agents explore 3D volumes and are rewarded based on their distance to the target landmark. They learn to communicate to increase their accuracy.We used data from 370 participants (HCN=131, CBS=80, PSP=134, MSA=25 MSA) from the Cambridge Centre for Parkinsons Plus Disorders and the PROSPECT-M data split in training, testing and validation sets (70:15:15). Four landmarks from the midbrain and pons were manually recorded, using Massey et al.’s annotation method [1].ROC analysis was carried out to assess the efficacy of the MPR in discriminating PSP from other APS.Results: The algorithm was accurate in identifying landmarks (mean error 0.8mm, SD 0.3mm), resulting in an accurate measurement of MPR (mean percent error 3.7, SD 1.7).The MPR was significantly smaller in PSP patients in comparison to all other groups [Figure 1], with a high accuracy for distinguishing between groups (AUC values: HC0.98, MSA 0.97, CBD 0.90).Conclusion: We report a new highly accurate automated measure of MPR predictor using artificial intelligence. We demonstrate that the MPR is a useful diagnostic biomarker for distinguishing PSP from other atypical parkinsonian disorders.References: [1] Massey, L.A., Jäger, H.R., Paviour, D.C., O’Sullivan, S.S., Ling, H., Williams, D.R., Kallis, C., Holton, J., Revesz, T., Burn, D.J. and Yousry, T., 2013. The midbrain to pons ratio: a simple and specific MRI sign of progressive supranuclear palsy. Neurology, 80(20), pp.1856-1861.</p
Reply to the discussion by McCarron on “Modelling spatial variability in as-laid embedment for high pressure and high temperature (HPHT) pipeline design”
No full textN/AThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author
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