No drain, autologous transfusion drain or suction drain? A randomised prospective study in total hip replacement surgery of 168 patients

We performed a prospective, randomised controlled trial to assess the differences in the use of a conventional suction drain, an Autologous Blood Transfusion (ABT) drain and no drain, in 168 patients. There was no significant difference between the drainage from ABT drains ( mean : 345 ml) and the suction drain (314 ml). Forty percent of patients receiving a suction drain had a haemoglobin level less than 10 g/dL at 24 hours, compared to 35% with no drain and 28% with an ABT drain. Patients that had no drains had wounds that were dry significantly sooner, mean 3.0 days compared to a mean of 3.9 days with an ABT drain and a mean of 4 days with a suction drain. Patients that did not have a drain inserted stayed in hospital a significantly shorter period of time, compared with drains. We feel the benefits of quicker drying wounds, shorter hospital stays and the economic savings justify the conclusion that no drain is required after hip replacement

Refined Phenotyping of Modic Changes: Imaging biomarkers of prolonged severe low back pain and disability

Imaging biomarkers of prolonged severe low back pain and disablitypublished_or_final_versio

The theory of international business: the role of economic models

This paper reviews the scope for economic modelling in international business studies. It argues for multi-level theory based on classic internalisation theory. It present a systems approach that encompasses both firm-level and industry-level analysis

Charge asymmetries of top quarks at hadron colliders revisited

A sizeable difference in the differential production cross section of top- compared to antitop-quark production, denoted charge asymmetry, has been observed at the Tevatron. The experimental results seem to exceed the theory predictions based on the Standard Model by a significant amount and have triggered a large number of suggestions for "new physics". In the present paper the Standard Model predictions for Tevatron and LHC experiments are revisited. This includes a reanalysis of electromagnetic as well as weak corrections, leading to a shift of the asymmetry by roughly a factor 1.1 when compared to the results of the first papers on this subject. The impact of cuts on the transverse momentum of the top-antitop system is studied. Restricting the ttbar system to a transverse momentum less than 20 GeV leads to an enhancement of the asymmetries by factors between 1.3 and 1.5, indicating the importance of an improved understanding of the $t\bar t$-momentum distribution. Predictions for similar measurements at the LHC are presented, demonstrating the sensitivity of the large rapidity region both to the Standard Model contribution and effects from "new physics".Comment: 23 pages. Final version to appear in JHE

On-shell Recursion in String Theory

We prove that all open string theory disc amplitudes in a flat background obey Britto-Cachazo-Feng-Witten (BCFW) on-shell recursion relations, up to a possible reality condition on a kinematic invariant. Arguments that the same holds for tree level closed string amplitudes are given as well. Non-adjacent BCFW-shifts are related to adjacent shifts through monodromy relations for which we provide a novel CFT based derivation. All possible recursion relations are related by old-fashioned string duality. The field theory limit of the analysis for amplitudes involving gluons is explicitly shown to be smooth for both the bosonic string as well as the superstring. In addition to a proof a less rigorous but more powerful argument based on the underlying CFT is presented which suggests that the technique may extend to a much more general setting in string theory. This is illustrated by a discussion of the open string in a constant B-field background and the closed string on the level of the sphere.Comment: 36 + 9 pages text, one figure, v3: added discussion on relation to old-fashioned factorization, typos corrected, published versio

Overcoming obstacles associated with other learning experiences and school-based assessment: Perspectives of high school students with visual impairment in Hong Kong - Collaborative research project report

published_or_final_versio

Heart and liver R2 and R2* measurements in patients with thalassaemia major at 3T

Myocardial Tissue Characterization: Fat, Hemorrhage & Edema - Poster presentationTo determine the feasibility of measurements of transverse relaxation times for assessment of tissue iron overload at high field, we compared results of determinations of R2 and R2* using breathhold multi-echo spin-echo (MESE) and multi-echo gradient echo (MEGE) sequences, respectively, at 3T and at 1.5T in normal subjects and patients with thalassaemia major. Our results, the first reported measurements of R2 at both 3T and 1.5T in iron overloaded patients, demonstrate significant correlations in heart and liver at the two field strengths. These results provide evidence that myocardial and hepatic R2 can be measured at 3T as indicators of iron overload.published_or_final_versionThe 17th Scientific Meeting & Exhibition of the International Society of Magnetic Resonance in Medicine (ISMRM), Honolulu, HI., 18-24 April 2009. In Proceedings of ISMRM 17th Scientific Meeting & Exhibition, 2009, p. 375

Explaining the t tbar forward-backward asymmetry without dijet or flavor anomalies

We consider new physics explanations of the anomaly in the top quark forward-backward asymmetry measured at the Tevatron, in the context of flavor conserving models. The recently measured LHC dijet distributions strongly constrain many otherwise viable models. A new scalar particle in the antitriplet representation of flavor and color can fit the t tbar asymmetry and cross section data at the Tevatron and avoid both low- and high-energy bounds from flavor physics and the LHC. An s-channel resonance in uc to uc scattering at the LHC is predicted to be not far from the current sensitivity. This model also predicts rich top quark physics for the early LHC from decays of the new scalar particles. Single production gives t tbar j signatures with high transverse momentum jet, pair production leads to t tbar j j and 4 jet final states.Comment: 7 pages, 6 figures; v2: notation clarified, references adde

Étude de cas : explorer l'impact des modèles imprimés en 3D sur l'intégration cognitive durant la formation aux compétences cliniques

Background: Cognitive integration occurs when trainees make conceptual connections between relevant knowledges and is known to improve learning. While several experimental studies have demonstrated how text and audio-visual instruction can be designed to enhance cognitive integration, clinical skills training in real-world contexts may require alternative educational strategies. Introducing three-dimensional (3D) printed models during clinical skills instruction may offer unique learning opportunities to support cognitive integration. Methods: Using case study methodology, we explore how learners and an instructor used 3D printed bones to augment their learning interactions during a clinical skills laboratory on shoulder on palpation, and to describe the instructional strategies with 3D printed bones that may support learning. Students (n = 21) worked in small groups and were given access to a 3D printed clavicle, scapula, and humerus. Data were collected through observation, a student focus group, and a semi-structured interview with the instructor. Thematic analysis to review and code the data and to generate themes. Results:  We developed four themes that describe how 3D printed models were used in the classroom and how they may support cognitive integration: classroom interactivity, visualization of anatomy, integrating knowledge, and educational potential. Conclusions: The findings demonstrate several ways 3D printed models can augment how learners, instructors, and educational materials interact with one another and how readily learners make connections between different sources and types of knowledge. This research extends previous work by demonstrating how social learning processes and interactions with physical models can offer unique affordances that may support cognitive integration.Contexte : L'intégration cognitive se produit lorsque les apprenants établissent des liens conceptuels entre des connaissances pertinentes et est connue pour améliorer l'apprentissage. Alors que plusieurs études expérimentales ont démontré comment le texte et l'enseignement audiovisuel peuvent être conçus pour améliorer l'intégration cognitive, la formation aux compétences cliniques dans des contextes réels peut nécessiter d'autres stratégies éducatives. L'introduction de modèles imprimés en trois dimensions (3D) dans l'enseignement des compétences cliniques peut offrir des occasions d'apprentissage uniques pour favoriser l'intégration cognitive. Méthodes : En utilisant la méthodologie des études de cas, cette étude explore comment les apprenants et un instructeur ont utilisé des os imprimés en 3D pour augmenter leurs interactions d'apprentissage au cours d'un laboratoire de compétences cliniques sur la palpation de l'épaule, et pour caractériser les stratégies d'enseignement avec des os imprimés en 3D qui peuvent favoriser l'apprentissage. Les étudiants (n=21) ont travaillé en petits groupes et ont eu accès à une clavicule, une omoplate et un humérus imprimés en 3D. Les données ont été collectées par l'observation, un groupe de discussion d'étudiants et un entretien semi-structuré avec l'instructeur. Une analyse thématique a permis de passer en revue  et de coder les données et de dégager des thèmes. Résultats :  Quatre thèmes ont été développés pour décrire comment les modèles imprimés en 3D ont été utilisés en classe et comment ils peuvent favoriser l'intégration cognitive : interactivité en classe, visualisation de l'anatomie, intégration des connaissances et potentiel éducatif. Conclusions : Les résultats démontrent que les modèles imprimés en 3D peuvent améliorer la façon dont les apprenants, les instructeurs et le matériel pédagogique interagissent et la facilité avec laquelle les apprenants établissent des liens entre les différents types et sources de connaissances. Cette recherche s’ajoute à des travaux antérieurs en démontrant comment les processus d'apprentissage social et les interactions avec les modèles physiques peuvent offrir des potentialités uniques susceptibles de favoriser l'intégration cognitive

LHC diphoton Higgs signal and top quark forward-backward asymmetry in quasi-inert Higgs doublet model

In the quasi-inert Higgs doublet model, we study the LHC diphoton rate for a standard model-like Higgs boson and the top quark forward-backward asymmetry at Tevatron. Taking into account the constraints from the vacuum stability, unitarity, electroweak precision tests, flavor physics and the related experimental data of top quark, we find that compared with the standard model prediction, the diphoton rate of Higgs boson at LHC can be enhanced due to the light charged Higgs contributions, while the measurement of the top quark forward-backward asymmetry at Tevatron can be explained to within $1\sigma$ due to the non-standard model neutral Higgs bosons contributions. Finally, the correlations between the two observables are discussed.Comment: 14 pages, 5 figues. Version to appear in JHEP, some references adde