648 research outputs found

    Two-week joint mobilization intervention improves self-reported function, range of motion, and dynamic balance in those with chronic ankle instability

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    We examined the effect of a 2-week anterior-to-posterior ankle joint mobilization intervention on weight-bearing dorsiflexion range of motion (ROM), dynamic balance, and self-reported function in subjects with chronic ankle instability (CAI). In this prospective cohort study, subjects received six Maitland Grade III anterior-to-posterior joint mobilization treatments over 2 weeks. Weightbearing dorsiflexion ROM, the anterior, posteromedial, and posterolateral reach directions of the Star Excursion Balance Test (SEBT), and self-reported function on the Foot and Ankle Ability Measure (FAAM) were assessed 1 week before the intervention (baseline), prior to the first treatment (pre-intervention), 24–48 h following the final treatment (post-intervention), and 1 week later (1-week follow-up) in 12 adults (6 males and 6 females) with CAI. The results indicate that dorsiflexion ROM, reach distance in all directions of the SEBT, and the FAAM improved (p < 0.05 for all) in all measures following the intervention compared to those prior to the intervention. No differences were observed in any assessments between the baseline and pre-intervention measures or between the postintervention and 1-week follow-up measures (p > 0.05). These results indicate that the joint mobilization intervention that targeted posterior talar glide was able to improve measures of function in adults with CAI for at least 1 week

    Effects of post-printing heat treatment on microstructure, corrosion and wet wear behavior of CoCrW alloy produced by L-PBF process

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    CoCr alloys are widely used as human implants because of both their superior corrosion resistance and superior mechanical properties (fatigue, wear resistance, etc.) respect to other metal alloys used in biomedical field. In particular, CoCrW alloys are used mainly to produce dental implants. In this study, the effects of thermal treatment on the corrosion resistance and wet wear resistance of CoCrW alloys produced via Laser-Powder Bed Fusion (L-PBF) were investigated, and the corrosion resistance and wet wear resistance of the L-PBF specimens were compared with those of the specimens obtained after forging. The heat treatment involved the solubilization of the alloy at 1150 °C in an Ar-saturated atmosphere, followed by furnace cooling. A detailed microstructural characterization of the L-PBF specimens was carried out using a light microscope and a scanning electron microscope in both the horizontal and vertical growth directions. Scanning Kelvin probe measurements were performed on the heat-treated specimens obtained by three-dimensional printing and forging. The void contents of the specimens were evaluated using the Archimedes’ method and image analysis. Vickers (HV2) hardness measurements were performed to evaluate the mechanical properties of the specimens. The corrosion properties of the specimens were evaluated by carrying out potentiodynamic tests in two different corrosive media (aqueous solution (9 g/L NaCl) at pH = 2 and 7). The corroded areas of the specimens were then examined using scanning electron microscopy (SEM). Finally, tribological tests were performed using the pin (Ti counter material)-on-flat configuration under dry and wet conditions, using the same corrosive environments as those used in the potentiodynamic tests and two different stroke lengths. The worn samples were characterized using SEM to investigate their wear mechanisms, and a stylus profilometer was used to determine the wear rates of the materials. The experimental results showed that the additively manufactured CoCrW L-PBF alloy had higher corrosion resistance than the wrought material. In addition, the additively manufactured material showed better dry and wet wear performances than the wrought material. Nevertheless, the heat treatment did not affect the properties evaluated in this study

    From music to mathematics and backwards: introducing algebra, topology and category theory into computational musicology

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    International audienceDespite a long historical relationship between mathematics and music, the interest of mathematicians is a recent phenomenon. In contrast to statistical methods and signal-based approaches currently employed in MIR (Music Information Research), the research project described in this paper stresses the necessity of introducing a structural multidisciplinary approach into computational musicology making use of advanced mathematics. It is based on the interplay between three main mathematical disciplines: algebra, topology and category theory. It therefore opens promising perspectives on important prevailing challenges, such as the automatic classification of musical styles or the solution of open mathematical conjectures, asking for new collaborations between mathematicians, computer scientists, musicologists, and composers. Music can in fact occupy a strategic place in the development of mathematics since music-theoretical constructions can be used to solve open mathematical problems. The SMIR project also differs from traditional applications of mathematics to music in aiming to build bridges between different musical genres, ranging from contemporary art music to popular music, including rock, pop, jazz and chanson. Beyond its academic ambition, the project carries an important societal dimension stressing the cultural component of 'mathemusical' research, that naturally resonates with the underlying philosophy of the “Imagine Maths”conference series. The article describes for a general public some of the most promising interdisciplinary research lines of this project

    Hey Maths ! Modèles formels et computationnels au service des Beatles

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    Cet article livre quelques réflexions sur les modèles formels et computationnels dans et pour les musiques populaires tout en mettant l’accent sur les chansons des Beatles. Après une présentation rapide des approches systématiques dans l’analyse de la forme, mais aussi des outils théoriques à la base de la représentation géométrique des structures et des processus musicaux (Tonnetz, constructions issues de la tradition analytique néo-riemannienne), les auteurs évoquent les questions que soulève l’analyse d’une collection de chansons des Beatles dès lors qu’on les envisage d’un point de vue formel et computationnel. En effet, si la forme et la structure des chansons des Beatles peuvent être étudiées sans recourir à des outils mathématiques, la modélisation informatique du processus de segmentation d’une pièce de musique, ainsi que les techniques issues du Music Information Retrieval, permettent d’approcher ces chansons d’un point de vue computationnel tout en posant la question de leur singularité par rapport à d’autres musiques elles aussi qualifiées de « populaires ».This article proposes some thoughts on formal and computational models in and for popular music by focusing on Beatles songs. After a brief presentation of some systematic approaches in the analysis of musical form and of some theoretical tools used in the geometric representation of musical structures and processes (the Tonnetz and other Neo-Riemannian constructions), the authors deal with the questions raised by the analysis of a collection of Beatles songs once they are studied either from a formal or a computational viewpoint. Even though the form and the structure of Beatles songs can be studied without using mathematical tools, the computer-aided modelling of the segmentation process of a musical piece, as well as the techniques belonging to the field of Music Information Retrieval, allow to give a quantitative, computational-oriented interpretation of Pop songs. At the same time, this approach opens the question of the singularity of this repertoire with respect to other popular music pieces

    The Multi-allelic Genetic Architecture of a Variance-Heterogeneity Locus for Molybdenum Concentration in Leaves Acts as a Source of Unexplained Additive Genetic Variance

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    Funding: We acknowledge support from the US National Institutes of Health (http://www.nih.gov/) (grant 2R01GM078536 to DES), European Commission (http://ec.europa.eu/index_en.htm) (grant PCIG9-GA-2011-291798 to DES) and UK Biotechnology and Biological Sciences Research Council (http://www.bbsrc.ac.uk/) (grants BB/L000113/1 to DES). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    On a Conjecture of Rapoport and Zink

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    In their book Rapoport and Zink constructed rigid analytic period spaces FwaF^{wa} for Fontaine's filtered isocrystals, and period morphisms from PEL moduli spaces of pp-divisible groups to some of these period spaces. They conjectured the existence of an \'etale bijective morphism FaFwaF^a \to F^{wa} of rigid analytic spaces and of a universal local system of QpQ_p-vector spaces on FaF^a. For Hodge-Tate weights n1n-1 and nn we construct in this article an intrinsic Berkovich open subspace F0F^0 of FwaF^{wa} and the universal local system on F0F^0. We conjecture that the rigid-analytic space associated with F0F^0 is the maximal possible FaF^a, and that F0F^0 is connected. We give evidence for these conjectures and we show that for those period spaces possessing PEL period morphisms, F0F^0 equals the image of the period morphism. Then our local system is the rational Tate module of the universal pp-divisible group and enjoys additional functoriality properties. We show that only in exceptional cases F0F^0 equals all of FwaF^{wa} and when the Shimura group is GLnGL_n we determine all these cases.Comment: v2: 48 pages; many new results added, v3: final version that will appear in Inventiones Mathematica

    Effect of Thermal Treatment on Corrosion Behavior of AISI 316L Stainless Steel Manufactured by Laser Powder Bed Fusion

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    The effect of post-processing heat treatment on the corrosion behavior of AISI 316L stainless steel manufactured by laser powder bed fusion (L-PBF) is investigated in this work. Produced stainless steel was heat treated in a broad temperature range (from 200 °C to 1100 °C) in order to evaluate the electrochemical behavior and morphology of corrosion. The electrochemical behavior was investigated by potentiodynamic and galvanostatic polarization in a neutral and acidic (pH 1.8) 3.5% NaCl solution. The microstructure modification after heat treatment and the morphology of attack of corroded samples were evaluated by optical and scanning electron microscopy. The fine cellular/columnar microstructure typically observed for additive-manufactured stainless steel evolves into a fine equiaxed austenitic structure after thermal treatment at high temperatures (above 800 °C). The post-processing thermal treatment does not negatively affect the electrochemical behavior of additive-manufactured stainless steel even after prolonged heat treatment at 1100 °C for 8 h and 24 h. This indicates that the excellent barrier properties of the native oxide film are retained after heat treatment
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