BIOMECHANICAL APPROACH TO BALLET MOVEMENTS: A PRELIMINARY STUDY

Movements in ballet dance often involve extreme joint positions and muscular efforts that may exceed normal ranges of motion and generate high stresses on bone and soft tissues. The primary aim of this study was to apply the principles and techniques of biomechanics to study ballet movements. Ground reaction forces and plantar pressure distribution were registered with a Kistler Platform and a Tekscan Systems respectively. Knee joint action in the sagittal plane was simultaneously collected with an electrogoniometer. Peak vertical forces, peak pressures and knee flexion-extension were analyzed and discussed. A better understanding of these biomechanical aspects may lead to a decrease of the injury risks and also to more graceful and efficient dance movements

RACEWALKING AND NORMAL WALKING ANALYSIS

INTRODUCTION: The purpose of the present study was to observe biomechanical variations in racewalking, starting from normal walking and continuing on up to a maximum racewalking performance supported by the athlete. Tests were carried out on a women’s racewalking team who represents Santa Catarina State at national competitions in Brazil. A GaitwayTM instrumented treadmill system was used to verify the differences between normal walking and racewalking. A few studies have been made of race walkers. Some physiological aspects indicated that the speed at which racewalking and running become equally efficient is similar to the crossover speed for conventional walking and running (Hagberg & Coyle, 1984). Another important study was done by Morgan & Martin (1986), who showed the effects of stride length alterations on racewalking economy. Their results support the hypothesis that trained subjects select locomotion patterns that are nearly optimal in terms of the aerobic demands. Cairns et al. (1986) determined that the racewalking gait exhibits some biomechanical characteristics which are different from the walking gait or running. Recently, Brisswalter et al. (1996) suggested that in well trained walkers the energy cost of walking increases with exercise duration, but walkers are able to maintain the same stride duration after the test when treadmill speed is controlled

Curricular orientations to real-world contexts in mathematics

A common claim about mathematics education is that it should equip students to use mathematics in the ‘real world’. In this paper, we examine how relationships between mathematics education and the real world are materialised in the curriculum across a sample of eleven jurisdictions. In particular, we address the orientation of the curriculum towards application of mathematics, the ways that real-world contexts are positioned within the curriculum content, the ways in which different groups of students are expected to engage with real-world contexts, and the extent to which high-stakes assessments include real-world problem solving. The analysis reveals variation across jurisdictions and some lack of coherence between official orientations towards use of mathematics in the real world and the ways that this is materialised in the organisation of the content for students

Safer_RAIN: A DEM-based hierarchical filling-&-spilling algorithm for pluvial flood hazard assessment and mapping across large urban areas

The increase in frequency and intensity of extreme precipitation events caused by the changing climate (e.g., cloudbursts, rainstorms, heavy rainfall, hail, heavy snow), combined with the high population density and concentration of assets, makes urban areas particularly vulnerable to pluvial flooding. Hence, assessing their vulnerability under current and future climate scenarios is of paramount importance. Detailed hydrologic-hydraulic numerical modeling is resource intensive and therefore scarcely suitable for performing consistent hazard assessments across large urban settlements. Given the steadily increasing availability of LiDAR (Light Detection And Ranging) high-resolution DEMs (Digital Elevation Models), several studies highlighted the potential of fast-processing DEM-based methods, such as the Hierarchical Filling-&-Spilling or Puddle-to-Puddle Dynamic Filling-&-Spilling Algorithms (abbreviated herein as HFSAs). We develop a fast-processing HFSA, named Safer_RAIN, that enables mapping of pluvial flooding in large urban areas by accounting for spatially distributed rainfall input and infiltration processes through a pixel-based Green-Ampt model. We present the first applications of the algorithm to two case studies in Northern Italy. Safer_RAIN output is compared against ground evidence and detailed output from a two-dimensional (2D) hydrologic and hydraulic numerical model (overall index of agreement between Safer_RAIN and 2D benchmark model: sensitivity and specificity up to 71% and 99%, respectively), highlighting potential and limitations of the proposed algorithm for identifying pluvial flood-hazard hotspots across large urban environments

A criterion for separating process calculi

We introduce a new criterion, replacement freeness, to discern the relative expressiveness of process calculi. Intuitively, a calculus is strongly replacement free if replacing, within an enclosing context, a process that cannot perform any visible action by an arbitrary process never inhibits the capability of the resulting process to perform a visible action. We prove that there exists no compositional and interaction sensitive encoding of a not strongly replacement free calculus into any strongly replacement free one. We then define a weaker version of replacement freeness, by only considering replacement of closed processes, and prove that, if we additionally require the encoding to preserve name independence, it is not even possible to encode a non replacement free calculus into a weakly replacement free one. As a consequence of our encodability results, we get that many calculi equipped with priority are not replacement free and hence are not encodable into mainstream calculi like CCS and pi-calculus, that instead are strongly replacement free. We also prove that variants of pi-calculus with match among names, pattern matching or polyadic synchronization are only weakly replacement free, hence they are separated both from process calculi with priority and from mainstream calculi.Comment: In Proceedings EXPRESS'10, arXiv:1011.601

Central nervous system metastases from castration-resistant prostate cancer in the docetaxel era.

Central nervous system (brain or leptomeningeal) metastases (BLm) are considered rare in castration-resistant prostate cancer (CRPC) patients. Now that docetaxel has become the reference drug for first-line treatment of CRPC, patients whose disease is not controlled by hormonal manipulations may live much longer than before and have higher risk of developing BLm. We retrospectively reviewed the records of all patients with CRPC attending our centres from 2002 to 2010, and identified all of those who were diagnosed as having BLm and received (or were considered to have been eligible to receive) docetaxel-based treatment. We identified 31 cases of BLm (22 brain metastases and 9 leptomeningeal metastases) with an incidence of 3.3%. BLm-free survival was 43.5 months, and survival after BLm discovery was 4 months. With six patients surviving for more than 1 year after developing BLm, the projected 1-year BL-S rate was 25.8%. The findings of our study may be relevant in clinical practice as they indicate that incidence of BLm in CRPC patients in the docetaxel era seems to be higher than in historical reports, meaning that special attention should be paid to the appearance of neurological symptoms in long-term CRPC survivors because they may be related to BLm

GeantV: Results from the prototype of concurrent vector particle transport simulation in HEP

Full detector simulation was among the largest CPU consumer in all CERN experiment software stacks for the first two runs of the Large Hadron Collider (LHC). In the early 2010's, the projections were that simulation demands would scale linearly with luminosity increase, compensated only partially by an increase of computing resources. The extension of fast simulation approaches to more use cases, covering a larger fraction of the simulation budget, is only part of the solution due to intrinsic precision limitations. The remainder corresponds to speeding-up the simulation software by several factors, which is out of reach using simple optimizations on the current code base. In this context, the GeantV R&D project was launched, aiming to redesign the legacy particle transport codes in order to make them benefit from fine-grained parallelism features such as vectorization, but also from increased code and data locality. This paper presents extensively the results and achievements of this R&D, as well as the conclusions and lessons learnt from the beta prototype.Comment: 34 pages, 26 figures, 24 table

Compiling Pattern Matching in Join-Patterns

We propose an extension of the join-calculus with pattern matching on algebraic data types. Our initial motivation is twofold: to provide an intuitive semantics of the interaction between concurrency and pattern matching; to define a practical compilation scheme from extended join-definitions into ordinary ones plus (ML) pattern matching. To assess the correctness of our compilation scheme, we develop a theory of the applied join-calculus, a calculus with value-passing and value matching

Plasma exosome profile in st-elevation myocardial infarction patients with and without out-of-hospital cardiac arrest

The identification of new biomarkers allowing an early and more accurate characterization of patients with ST-segment elevation myocardial infarction (STEMI) is still needed, and exosomes represent an attractive diagnostic tool in this context. However, the characterization of their protein cargo in relation to cardiovascular clinical manifestation is still lacking. To this end, 35 STEMI patients (17 experiencing resuscitated out-of-hospital cardiac arrest (OHCA-STEMI) and 18 uncomplicated) and 32 patients with chronic coronary syndrome (CCS) were enrolled. Plasma exosomes were characterized by the nanoparticle tracking analysis and Western blotting. Exosomes from STEMI patients displayed a higher concentration and size and a greater expression of platelet (GPIIb) and vascular endothelial (VE-cadherin) markers, but a similar amount of cardiac troponin compared to CCS. In addition, a difference in exosome expression of acute-phase proteins (ceruloplasmin, transthyretin and fibronectin) between STEMI and CCS patients was found. GPIIb and brain-associated marker PLP1 accurately discriminated between OHCA and uncomplicated STEMI. In conclusion, the exosome profile of STEMI patients has peculiar features that differentiate it from that of CCS patients, reflecting the pathophysiological mechanisms involved in STEMI. Additionally, the exosome expression of brain-and platelet-specific markers might allow the identification of patients experiencing ischemic brain injury in STEMI

Barbed suture vs conventional tenorrhaphy: biomechanical analysis in an animal model.

BACKGROUND: The advantages of barbed suture for tendon repair could be to eliminate the need for a knot and to better distribute the load throughout the tendon so as to reduce the deformation at the repair site. The purpose of this study was to evaluate the breaking force and the repair site deformation of a new barbed tenorrhaphy technique in an animal model. MATERIALS AND METHODS: Sixty porcine flexor tendons were divided randomly into three groups and repaired with one of the following techniques: a new 4-strand barbed technique using 2/0 polypropylene Quill™ SRS or 2/0 polydioxanone Quill™ SRS and a modified Kessler technique using 3/0 prolene. All tendons underwent mechanical testing to assess the 2-mm gap formation force, the breaking force and the mode of failure. The percentage change in tendon cross-sectional area before and after repair was calculated. RESULTS: The two-sample Student t-test demonstrated a significant increase in 2-mm gap formation force and in breaking force with barbed sutures, independently from suture material, when compared to traditional Kessler suture. Concerning the tendon profile, we registered less bunching at the repair site in the two barbed groups compared with the Kessler group. CONCLUSIONS: This study confirms the promising results achieved in previous ex vivo studies about the use of barbed suture in flexor tendon repair. In our animal model, tenorrhaphy with Quill™ SRS suture guarantees a breaking force of repair that exceeds the 40-50 N suggested as sufficient to initiate early active motion, and a smoother profile at the repair site. LEVEL OF EVIDENCE: Not applicable