249 research outputs found

    Re-examining the effects of verbal instructional type on early stage motor learning

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    The present study investigated the differential effects of analogy and explicit instructions on early stage motor learning and movement in a modified high jump task. Participants were randomly assigned to one of three experimental conditions: analogy, explicit light (reduced informational load), or traditional explicit (large informational load). During the two-day learning phase, participants learned a novel high jump technique based on the ‘scissors’ style using the instructions for their respective conditions. For the single-day testing phase, participants completed both a retention test and task-relevant pressure test, the latter of which featured a rising high-jump-bar pressure manipulation. Although analogy learners demonstrated slightly more efficient technique and reported fewer technical rules on average, the differences between the conditions were not statistically significant. There were, however, significant differences in joint variability with respect to instructional type, as variability was lowest for the analogy condition during both the learning and testing phases, and as a function of block, as joint variability decreased for all conditions during the learning phase. Findings suggest that reducing the informational volume of explicit instructions may mitigate the deleterious effects on performance previously associated with explicit learning in the literature

    Geoarqueología y paleontología de los depósitos de Pleistoceno Superior del antiguo Arroyo Abroñigal (Cuenca de Manzanares, Madrid): el yacimiento de Puente de los Tres Ojos

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    La excavación arqueológica del yacimiento del Puente de los Tres Ojos, próximo a la calle Cerro Negro (Madrid), ha aportado nuevos datos para profundizar en el conocimiento de la ocupación humana y en la reconstrucción paleoambiental del valle del antiguo arroyo Abroñigal, cuyo curso fluvial funcionó como afluente del río Manzanares posiblemente desde antes del Pleistoceno Superior hasta la segunda mitad del siglo XX. En el presente artículo se incluyen los aspectos geomorfológicos y cronoestratigráficos de los niveles excavados, documentándose varias secuencias fluviales y aluviales de relleno de la margen derecha del fondo de valle del Abroñigal en su tramo inferior. Durante la excavación se registró un amplio conjunto lítico, formado en su mayoría por piezas recuperadas en niveles de arenas y gravas correspondientes a episodios fluviales de media energía, a las que hay que añadir un porcentaje menor localizado en niveles de limos arcillosos y arenas finas. La mayor parte del conjunto lítico responde a sistemas técnicos propios del Paleolítico Medio, aunque destaca la presencia testimonial de piezas del Paleolítico Superior, además de restos de fauna de mamíferos correspondientes al Pleistoceno Superior, todo ello en niveles datados por OSL entre 14.400 y 11.170 años BP aproximadament

    The planarity of the stickface motion in the field hockey hit

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    The field hockey hit is an important but poorly understood stroke. This study investigated the planarity of the stickface motion during the downswing, in order to better characterise the kinematics and to assess the suitability of planar pendulum models for simulating the hit. Thirteen experienced female field hockey players were filmed executing hits with a single approach step, and the kinematics of the centre of the stickface were measured. A method was developed for identifying how far back from impact the stickface motion was planar. Orthogonal least-squares regression was used to determine best-fit planes for sections of the stickface path of varying length, each of which ended at impact, and these sections were considered planar if the mean residual between the stickface path and the fitted plane was less than 0.25% of the distance traveled by the stickface during that period. On average the stickface motion was planar for the last 83±12% of its downswing path, with the length of the planar section ranging from 1.85 m to 2.70 m. The suitability of a planar model for the stickface motion was supported, but further investigation of the stick and arm kinematics is warranted

    The planarity of the stickface motion in the field hockey hit

    Get PDF
    The field hockey hit is an important but poorly understood stroke. This study investigated the planarity of the stickface motion during the downswing, in order to better characterise the kinematics and to assess the suitability of planar pendulum models for simulating the hit. Thirteen experienced female field hockey players were filmed executing hits with a single approach step, and the kinematics of the centre of the stickface were measured. A method was developed for identifying how far back from impact the stickface motion was planar. Orthogonal least-squares regression was used to determine best-fit planes for sections of the stickface path of varying length, each of which ended at impact, and these sections were considered planar if the mean residual between the stickface path and the fitted plane was less than 0.25% of the distance traveled by the stickface during that period. On average the stickface motion was planar for the last 83±12% of its downswing path, with the length of the planar section ranging from 1.85 m to 2.70 m. The suitability of a planar model for the stickface motion was supported, but further investigation of the stick and arm kinematics is warranted

    Cholesterol levels affect the performance of aunps-decorated thermo-sensitive liposomes as nanocarriers for controlled doxorubicin delivery

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    Stimulus-responsive liposomes (L) for triggering drug release to the target site are particularly useful in cancer therapy. This research was focused on the evaluation of the effects of cholesterol levels in the performance of gold nanoparticles (AuNPs)-functionalized L for controlled doxorubicin (D) delivery. Their interfacial and morphological properties, drug release behavior against temperature changes and cytotoxic activity against breast and ovarian cancer cells were studied. Langmuir isotherms were performed to identify the most stable combination of lipid components. Two mole fractions of cholesterol (3.35 mol% and 40 mol%, L1 and L2 series, respectively) were evaluated. Thin-film hydration and transmembrane pH-gradient methods were used for preparing the L and for D loading, respectively. The cationic surface of L allowed the anchoring of negatively charged AuNPs by electrostatic interactions, even inducing a shift in the zeta potential of the L2 series. L exhibited nanometric sizes and spherical shape. The higher the proportion of cholesterol, the higher the drug loading. D was released in a controlled manner by diffusion-controlled mechanisms, and the proportions of cholesterol and temperature of release media influenced its release profiles. D-encapsulated L preserved its antiproliferative activity against cancer cells. The developed liposomal formulations exhibit promising properties for cancer treatment and potential for hyperthermia therapy.Ministerio de Ciencia e Innovación CTQ2014- 57515-C2-

    Emapalumab in children with primary hemophagocytic lymphohistiocytosis

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    Primary hemophagocytic lymphohistiocytosis is a rare syndrome characterized by immune dysregulation and hyperinflammation. It typically manifests in infancy and is associated with high mortality. METHODS We investigated the efficacy and safety of emapalumab (a human anti-interferon-γ antibody), administered with dexamethasone, in an open-label, single-group, phase 2-3 study involving patients who had received conventional therapy before enrollment (previously treated patients) and previously untreated patients who were 18 years of age or younger and had primary hemophagocytic lymphohistiocytosis. The patients could enter a long-term follow-up study until 1 year after allogeneic hematopoietic stem-cell transplantation or until 1 year after the last dose of emapalumab, if transplantation was not performed. The planned 8-week treatment period could be shortened or extended if needed according to the timing of transplantation. The primary efficacy end point was the overall response, which was assessed in the previously treated patients according to objective clinical and laboratory criteria. RESULTS At the cutoff date of July 20, 2017, a total of 34 patients (27 previously treated patients and 7 previously untreated patients) had received emapalumab; 26 patients completed the study. A total of 63% of the previously treated patients and 65% of the patients who received an emapalumab infusion had a response; these percentages were significantly higher than the prespecified null hypothesis of 40% (P=0.02 and P=0.005, respectively). In the previously treated group, 70% of the patients were able to proceed to transplantation, as were 65% of the patients who received emapalumab. At the last observation, 74% of the previously treated patients and 71% of the patients who received emapalumab were alive. Emapalumab was not associated with any organ toxicity. Severe infections developed in 10 patients during emapalumab treatment. Emapalumab was discontinued in 1 patient because of disseminated histoplasmosis. CONCLUSIONS Emapalumab was an efficacious targeted therapy for patients with primary hemophagocytic lymphohistiocytosis

    Emapalumab in children with primary hemophagocytic lymphohistiocytosis

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    Primary hemophagocytic lymphohistiocytosis is a rare syndrome characterized by immune dysregulation and hyperinflammation. It typically manifests in infancy and is associated with high mortality

    Fatigue limit of recycled aggregate concrete

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    This paper presents the main results of the research carried out to obtain the fatigue limit of concrete incorporating recycled aggregate from concrete. In this research, recycled aggregate concretes with partial and total coarse aggregate replacement and control concretes with different increasing water/cement ratios have been cast to study the material’s behavior in response to repeated compressive loads. The results show that, for the same water/cement ratio, the recycled aggregate concretes present a loss of stiffness higher than the control concrete. Furthermore, the use of recycled aggregate in concrete implies a reduction of the fatigue life. These differences are increased for low water/cement ratios, as in this case the main factor is the lower strength capacity of the aggregate. From the results obtained, recommendable mixtures for recycled aggregates exposed to fatigue loads are proposed
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