679 research outputs found
Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery
No full textIn the version of this article initially published, the ATLAS Collaboration
author names, affiliations and acknowledgements were omitted and
have now been included in the HTML and PDF versions of the article
Automatic segmentation of lumbar vertebrae in digital videofluoroscopic images
No full textLow back pain is a significant problem in the industrialized world. Diagnosis of the underlying causes can be extremely difficult. Since mechanical factors often play an important role, it can be helpful to study the motion of the spine. Digital videofluoroscopy has been developed for this study and it can provide image sequences with many frames, but which often suffer due to noise, exacerbated by the very low radiation dosage. Thus, determining vertebra position within the image sequence presents a considerable challenge.There have been many studies on vertebral image extraction, but problems of repeatability, occlusion and out-of-plane motion persist. In this paper, we show how the Hough transform (HT) can be used to solve these problems. Here, Fourier descriptors were used to describe the vertebral body shape. This description was incorporated within our HT algorithm from which we can obtain affine transform parameters, i.e., scale, rotation and center position. The method has been applied to images of a calibration model and to images from two sequences of moving human lumbar spines. The results show promise and potential for object extraction from poor quality images and that models of spinal movement can indeed be derived for clinical application
Cultural influences on low back pain - Extending the biopsychosocial model
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The present investigation examined the influence of cultural factors on Low Back Pain (LBP). Multiple regression techniques were used to determine the relative importance of clinical, social and psychological factors to LBP disability and cultural influences on these factors were then explored. The findings indicated that compared to clinical and social factors, LBP disability was most strongly associated with psychological factors (adjusted R2 change = 0.38, p<0.00), the most important of which was psychological distress. Clinical (adjusted R2 change = 0.11, p<0.00) or social (adjusted R2 change = 0.02, p=0.09) factors were only moderately or weakly associated with LBP disability. A series of hierarchical regression models examined the mediating role of cognitive Coping Strategies (Catastrophising & Praying and Hoping (Rosenstiel and Keefe (1983)) and Pain Control Beliefs (Control of Pain &
Responsibility for management of Pain (Main and Waddell (1991)) on the relationship between LBP disability and distress. In support of the Cognitive Behavioural Mediational Model of chronic pain (Rudy and Turk, 1987), evidence was found to suggest that the relationship between LBP disability and distress was largely dependent upon Coping Strategies and Pain Control Beliefs. The findings also suggested that Pain Control Beliefs were largely dependent upon Coping strategies, although these relationships varied between specific Pain Control Beliefs and Coping Strategies. The study found evidence to suggest that certain self report questionnaires which are commonly used to assess cognitive factors associated with LBP may not have robust cross cultural reliabilities as measured by Cronbach's Alpha (Cronbach 1951) (Praying and Hoping (P&H) subscale of the Coping Strategies Questionnaire (CSQ) Rosensteil and Keefe 1983; Pain Responsibility (PR) subscale of the Pain Locus of Control (PLC) Main and Waddell 1991). The findings indicated that when used in their present form, these self reported questionnaires may provide inconsistent results with South Asian, African-born or Muslim LBP patients. The study provided evidence for the role of Cultural factors (self defined Ethnicity, Country of Birth and reported Religious Affiliation) on the experience of LBP. Although the relationship between cultural factors and LBP was generally weak (R2 change < 0.15), it appeared that South Asian, African-born and Muslim patients experienced LBP significantly worse than other LBP patients. The cultural group differences were strongest for the "passive" coping strategy "Praying and Hoping" (Rosensteil and Keefe 1983) (R2 change = 0.15, p < 0.001). The most apparent cultural differences were for Muslim patients who compared with all other Religious groups consistently reported the worst experience of LBP. Muslim LBP patients were clinically more disabled than either Christian (mean Roland and Morris Disability Questionnaire (RMDQ) difference (Roland and Morris, 1983) = 4.13) or other (mean RMDQ difference = 4.29) LBP patients. The statistical control of clinical variables in the regression models led to the conclusion that these groups of patients had a more "chronic" experience of LBP. Religious affiliation may help to identify LBP patients who present to secondary care with more chronic symptoms of LBP. Standardisation of self report questionnaire in these cultural groups may improve the precision of these findings. The present investigation was primarily descriptive in that reasons for cultural differences were not empirically examined. However the study findings suggest potentially fruitful areas for further investigation particularly that work on the meaning of "Praying" as a coping strategy and on its relationship with LBP disability for non-Christian groups would appear warranted
Author Correction: A detailed map of Higgs boson interactions by the ATLAS experiment ten years after the discovery
No full textPHP257 Comparison of Economic Evaluation Between Three Major HTA Agencies. Is There a French Touch?
No full textSearch for long-lived charged particles using large specific ionisation loss and time of flight in 140 fb−1 of pp collisions at = 13 TeV with the ATLAS detector
No full textThis paper presents a search for massive, charged, long-lived particles with the ATLAS detector at the Large Hadron Collider using an integrated luminosity of 140 f b−1 of proton-proton collisions at √ s = 13 TeV. These particles are expected to move signifcantly slower than the speed of light. In this paper, two signal regions provide complementary sensitivity. In one region, events are selected with at least one charged-particle track with high transverse momentum, large specifc ionisation measured in the pixel detector, and time of fight to the hadronic calorimeter inconsistent with the speed of light. In the other region, events are selected with at least two tracks of opposite charge which both have a high transverse momentum and an anomalously large specifc ionisation. The search is sensitive to particles with lifetimes greater than about 3 ns with masses ranging from 200 GeV to 3 TeV. The results are interpreted to set constraints on the supersymmetric pair production
of long-lived R-hadrons, charginos and staus, with mass limits extending beyond those from previous searches in broad ranges of lifetime
Search for light long-lived neutral particles from Higgs boson decays via vector-boson-fusion production from pp collisions at √s = 13 TeV with the ATLAS detector
No full textA search is reported for long-lived dark photons with masses between 0.1 GeV and 15 GeV, from exotic decays of Higgs bosons produced via vector-boson-fusion. Events that contain displaced collimated Standard Model fermions reconstructed in the calorimeter or muon spectrometer are probed. This search uses the full LHC Run 2 (2015–2018) data sample collected in proton–proton collisions at √s = 13 TeV, corresponding to an integrated luminosity of 139
f
b
−
1
. Dominant backgrounds from Standard Model processes and non-collision sources are estimated using data-driven techniques. The observed event yields in the signal regions are consistent with the expected background. Upper limits on the Higgs boson to dark photon branching fraction are reported as a function of the dark photon mean proper decay length or of the dark photon mass and the coupling between the Standard Model and the potential dark sector. This search is combined with previous ATLAS searches obtained in the gluon–gluon fusion and WH production modes. A branching fraction above 10% is excluded at 95% CL for a 125 GeV Higgs boson decaying into two dark photons for dark photon mean proper decay lengths between 173 and 1296 mm and mass of 10 GeV
The role of cervical spine range of motion in recovery from whiplash associated disorders
No full textThis thesis investigates the role of cervical spine Range of Motion in the recovery from
Whiplash Associated Disorders.
In clinical practice, Health Care Professionals attach value to measurements of cervical spine
Range of Motion for diagnostic, prognostic and treatment evaluation purposes. A systematic
literature review found conflicting evidence as to whether cervical spine Range of Motion
was a prognostic factor following a whiplash injury. Greater understanding of prognostic
factors such as this may facilitate improvements in patient management.
A second systematic literature review investigated the reliability and validity of methods for
measuring cervical spine Range of Motion. The Cervical Range Of Motion (CROM) device
was found to be the most rigorously tested and clinimetrically promising method and was
subsequently investigated for intra- and inter-observer reliability in a group of whiplashinjured
individuals and found to be substantially reliable.
The CROM device was utilised in a longitudinal cohort study of 599 whiplash-injured
patients to investigate the prognostic value of cervical spine Range of Motion for neck painrelated
disability and patient-reported recovery at short, medium and long-term follow-up. A
patient-reported version of cervical spine Range of Motion was also evaluated as a
prognostic factor.
Although useful for explaining disability at the time of measurement, active, passive and
patient-reported forms of cervical spine Range of Motion were not significant prognostic
factors for poor outcome when other physical and psychosocial factors were accounted for.
The clinical implication of this research is that if patients are experiencing reduced cervical
spine Range of Motion a few weeks after their whiplash injury they will not necessarily have
a poor outcome in the longer term as is commonly believed at present
Atividade antinociceptiva e inflamatória da acupuntura no acuponto spleen 6 (SP6) em camundongos : análise dos seus mecanismos neurobiológicos
No full textTese (doutorado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-graduação em Neurociências, Florianópolis, 2013A acupuntura é uma técnica milenar usada, entre outras aplicações, parao alívio da dor. Neste trabalho buscou-se verificar o efeito da acupunturae seus mecanismos de ação em modelos de nocicepção e inflamação emcamundongos. A acupuntura manual (AM) foi realizada no acupontoSP6 (Spleen 6) e reduziu a nocicepção aguda induzida por ácido acético(AA) e pela formalina. O melhor perfil antinociceptivo foi obtidoatravés de inserção e retenção da agulha por 10 minutos, sendo que seuefeito perdurou por 120 minutos. Verificou-se também que a integridadedas fibras aferentes primárias, em especial do tipo C, foi essencial para oefeito da AM no acuponto SP6. Além disto, foi observado que o SP6 foio acuponto que reduziu de forma mais significativa a nocicepção agudacausada pelo AA e formalina quando comparado com os acupontosST35, BL57, KI3, GB39, LR5 e um não acuponto. A estimulação doacuponto SP6 também foi efetiva em reduzir a dor neuropática,caracterizada pela hipersensibilidade mecânica (HM) e térmica (calor)induzidas pela ligadura parcial do nervo ciático. É importante salientarque a redução da HM permaneceu inicialmente por 1 hora, porém, seprolongou por 6 horas (com 5 tratamentos) e depois 60 horas (com 10tratamentos). Verificou-se que a administração prévia de antagonista dereceptores kappa () opióides, colinérgicos (muscarínico e nicotínico),dopaminérgicos (D2) e adenosinérgicos (A1 perifericamente),preveniram o efeito antinociceptivo do SP6 no modelo do AA.Observou-se também que houve maior atividade da proteína cFos emáreas do encéfalo envolvidas na dor como o locus coeruleus (LC), asubstância cinzenta periaquetal (PAG), o núcleo magno da rafe (rafe), onúcleo paraventricular do hipotálamo (PVN), o hipocampo e a amígdalacentral (Ace), após a AM. A AM no SP6 reduziu o número total deleucócitos, o número de neutrófilos, a atividade da mieloperoxidase, apermeabilidade capilar e restabeleceu os níveis de citocinasIL(interleucina)-10 na cavidade peritoneal de animais submetidos aperitonite induzida por carragenina, sendo que este efeito foi em partedependente de glicocorticóides endógenos. A estimulação do acupontoSP6 também reduziu a HM e térmica (calor) em camundongos quereceberam carragenina (3%) via intramuscular, além de restabelecer osníveis de IL-10 no músculo. Além disto, a AM no SP6 foi capaz dealterar o número de macrófagos anti-inflamatórios com fenótipo M2 emrelação aos macrófagos inflamatórios M1, sem promover aumento nonúmero total de macrófagos no músculo dos animais que receberamcarragenina. Ainda, os efeitos antinociceptivo e anti-inflamatório da AMno SP6 não foram observados em animais nocautes para a citocina IL-10. Assim, os nossos dados estendem os dados da literatura e permitemsugerir que a AM no SP6 possui efeito antinociceptivo e antiinflamatóriopronunciado, devido a liberação de IL-10. <br
Software Performance of the ATLAS Track Reconstruction for LHC Run 3
No full textCharged particle reconstruction in the presence of many simultaneous proton–proton (pp) collisions in the LHC is a challenging task for the ATLAS experiment’s reconstruction software due to the combinatorial complexity. This paper describes the major changes made to adapt the software to reconstruct high-activity collisions with an average of 50 or more simultaneous pp interactions per bunch crossing (pile-up) promptly using the available computing resources. The performance of the key components of the track reconstruction chain and its dependence on pile-up are evaluated, and the improvement achieved compared to the previous software version is quantified. For events with an average of 60pp collisions per bunch crossing, the updated track reconstruction is twice as fast as the previous version, without significant reduction in reconstruction efficiency and while reducing the rate of combinatorial fake tracks by more than a factor two
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