412 research outputs found

    Lyapunov coefficients for Hopf bifurcations in systems with piecewise smooth nonlinearity

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    Motivated by models that arise in controlled ship maneuvering, we analyze Hopf bifurcations in systems with piecewise smooth nonlinear part. In particular, we derive explicit formulas for the generalization of the first Lyapunov coefficient to this setting. This generically determines the direction of branching (super- versus sub-criticality), but in general this differs from any fixed smoothening of the vector field. We focus on non-smooth nonlinearities of the form uiuju_i|u_j|, but our results are formulated in broader generality for systems in any dimension with piecewise smooth nonlinear part. In addition, we discuss some codimension-one degeneracies and apply the results to a model of a shimmying wheel.Comment: 39 pages, 10 figure

    Task and ego goal orientations in competitive sport: a quantitative review of the literature from 1989 to 2016

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    Achievement goal theory (AGT) is a dominant theoretical framework. The purposes of this review were (1) to provide a summary of the task and ego goal orientations literature in competitive sport as measured by the Task and Ego Orientations in Sport Questionnaire (TEOSQ) or the Perceptions of Success in Sport Questionnaire (POSQ), (2) to test the interdependence of the two goal orientations, and (3) to provide the estimated means for both orientations across a number of historically examined moderator variables. 260 studies met inclusion criteria totaling 80,959 unique participants across 39 countries and 32 sports. Youth samples were nearly 50% of all included studies. The meta-analyzed intercorrelations (rw=.18, z=9.96, p<.000) supported the conceptualized interdependence of the two goal orientations. The estimated mean values were 4.15+.30 (task) and 3.04+.51 (ego). However, differences, POSQ compared to TEOSQ, existed in the estimated means (g=.92 task; g=1.09 ego). Thus, the TEOSQ and POSQ samples for the moderator variables (i.e. sex, sport level, sport type, and collective/individualistic countries) were examined separately. Results both supported and refuted the hypotheses and also differed by measure. Because of TEOSQ and POSQ inconsistencies, an additional analysis was undertaken to examine whether the TEOSQ and POSQ differed to a common correlate motivation climate. This analysis revealed measurement differences in the ego to ego climate relationships. In conclusion, AGT has been extensively researched in competitive sport. The inconsistent pattern of results raises a number of future research questions

    Implantación y análisis de un sistema de respuesta interactiva en el aula

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    En el curso académico 2011/12 se ha introducido como innovación educativa en la ETSI de Telecomunicación de la UPM un sistema de respuesta interactiva basado en mandos de radio frecuencia para el soporte a la participación de los alumnos en el aula. El presente documento pretende describir la experiencia de su implantación en tres asignaturas de diferente tipología. De acuerdo a los resultados obtenidos hasta el momento, los alumnos estacan la facilidad de uso del sistema y la mejora en cuanto a su participación en clase, estando interesados en su utilización en otras asignaturas. Por parte de los profesores, destaca que se dispone de información instantánea del proceso de aprendizaje individualizado del alumno, lo que permite incidir inmediatamente en aquellas cuestiones con peores resultados. Los principales inconvenientes se centran en su baja aportación a la asistencia a clase y a la retención y comprensión de conceptos

    A Meta-Analytic Review of Achievement Goal Orientation Correlates in Competitive Sport: A Follow-Up to Lochbaum et al. (2016)

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    Recent quantitative research in competitive sport with the Task and Ego Orientations in Sport Questionnaire (TEOSQ) and Perceptions of Success Questionnaire (POSQ) pointed to a potential critical issue that the two questionnaires did not agree across a number tested hypotheses (Lochbaum, Kazak Çetinkalp, Graham, Wright, & Zazo, 2016). Thus, the present quantitative review examined whether correlates of the two achievement goal orientations were moderated by the two measures. To achieve this purpose, 772 unique correlates (489 TEOSQ, 283 POSQ; 402 task orientation, 370 ego orientation) from 93 studies spanning 1989-2016 from 32 countries with 26,387 participants were placed into 15 different categories and meta-analyzed. The task goal orientation was significantly and small to moderate in meaningfulness related to adaptive success factors (rw=.29), maladaptive success factors (rw=-.12), desirable behaviors (rw=.28), positive emotions (rw=.35), amotivation (rw=-.13), extrinsic motivation (rw=.20), external regulations (rw=.12), internal regulations (rw=.34), intrinsic motivation (rw=.47), the mastery/task climate (rw=.38), perceived competence (rw=.26), and trait selfesteem (rw=.35). The ego goal orientation was significantly and small in meaningfulness related to adaptive success factors (rw=.10), maladaptive success factors (rw=.12), negative emotions (rw=.11), undesirable behaviors (rw=.23), amotivation (rw=.16), extrinsic motivation (rw=.28), external regulation (rw=.21), intrinsic motivation (rw=.14), performance/ego climate (rw=.28), and perceived competence (rw=.17). The questionnaire measure was a significant moderator for the task goal orientation relationship with desirable behaviors (POSQ rw=.24; TEOSQ rw=.37), internal regulations (POSQ rw=.26; TEOSQ rw=.39), and trait self-esteem (POSQ rw=.45; TEOSQ rw=.32) and for the ego goal orientation relationship with performance/ego climate (POSQ rw=.34; TEOSQ rw=.24). Overall, the extent of the questionnaire type being a concern when examining correlates was fortunately minimal. Yet, differences in the two dominant measures exit. Recommendations for future research examining both the TEOSQ and POSQ were proposed

    Behavior change training for pregnant women's communication during birth: A randomized controlled trial.

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    Applying health psychological theories can improve communication interventions to empower pregnant women and ensure safe births. The aim was to test a short digital communication intervention based on the health action process approach. A randomized-controlled trial was conducted with pregnant women at two German university hospitals. The intervention group (NT1  = 225; NT2  = 142) received a 2.5 h online training focusing on communication planning, self-efficacy and communicating personal needs and preferences under difficult circumstances. This group was compared with a passive control group (NT1  = 199; NT2  = 144). Data from the N = 286 women with complete datasets were used for multilevel analyses. Data from all recruited N = 424 women were used for intention-to-treat analyses with multiple imputation. Both groups improved regarding communication behavior, quality of birth, action planning, coping planning and coping self-efficacy after birth, which was more pronounced in the intervention group. The intention-to-treat analyses confirmed the higher improvement for communication behavior, perceived quality of birth and coping planning. The intervention was related to improvements in pregnant women's communication behavior and quality of birth. Hence, future research and practice should apply and evaluate health psychological theories when targeting communication and empowerment

    Paleo and historical seismicity in Mallorca (Baleares, Spain): a preliminary approach

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    The island of Mallorca is subject to low seismic activity. The instrumental record shows that current seismicity is surficial (La isla de Mallorca presenta una actividad sísmica baja. El registro instrumental muestra que la sismicidad actual es superficial

    Basement membrane-rich Organoids with functional human blood vessels are permissive niches for human breast cancer metastasis

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    Metastasic breast cancer is the leading cause of death by malignancy in women worldwide. Tumor metastasis is a multistep process encompassing local invasion of cancer cells at primary tumor site, intravasation into the blood vessel, survival in systemic circulation, and extravasation across the endothelium to metastasize at a secondary site. However, only a small percentage of circulating cancer cells initiate metastatic colonies. This fact, together with the inaccessibility and structural complexity of target tissues has hampered the study of the later steps in cancer metastasis. In addition, most data are derived from in vivo models where critical steps such as intravasation/extravasation of human cancer cells are mediated by murine endothelial cells. Here, we developed a new mouse model to study the molecular and cellular mechanisms underlying late steps of the metastatic cascade. We have shown that a network of functional human blood vessels can be formed by co-implantation of human endothelial cells and mesenchymal cells, embedded within a reconstituted basement membrane-like matrix and inoculated subcutaneously into immunodeficient mice. The ability of circulating cancer cells to colonize these human vascularized organoids was next assessed in an orthotopic model of human breast cancer by bioluminescent imaging, molecular techniques and immunohistological analysis. We demonstrate that disseminated human breast cancer cells efficiently colonize organoids containing a functional microvessel network composed of human endothelial cells, connected to the mouse circulatory system. Human breast cancer cells could be clearly detected at different stages of the metastatic process: initial arrest in the human microvasculature, extravasation, and growth into avascular micrometastases. This new mouse model may help us to map the extravasation process with unprecedented detail, opening the way for the identification of relevant targets for therapeutic intervention

    Estudio a corto plazo en artroplastia total de cadera no cementada con par de fricción cerámica-cerámica

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    Se revisan 38 prótesis con par de fricción cerámica-cerámica en 31 pacientes intervenidos durante los años 2000 a 2003. La edad media era de 47,3 años. La valoración clínica con la escala de Harris pasó de 53 puntos de media en el preoperatorio a 97 en el postoperatorio lo que permitió establecer un 76,3% de resultados excelentes y un 23,7 de buenos. No hemos podido constatar ninguna complicación asociada al par cerámica-cerámica. Los resultados iniciales con el par cerámica-cerámica son superponibles a otras pares de fricción, su utilización en implantes que han demostrado su eficacia con otros pares de fricción, la mejoría en la fabricación y la estricta observación de la técnica quirúrgica permite obviar el riesgo de fractura. Merced a su baja incidencia de desgaste y buen comportamiento biológico representa una alternativa real para su implantación en pacientes jóvenes o con una actividad elevada.From 2000 to 2003, 38 patients underwent ceramic on ceramic bearing total hip artrhoplasty. Mean age was 47.3 years. Clinical evaluation with the harris hip score increased from 53 points preoperatively to 97 postoperatively. There were no complications associated with ceramic on ceramic bearing.Initial results are similar to those found with others bearing surfaces. The use of ceramics in implants that have shown their effectiviness with others bearing surfaces, improvement in manufactured of the ceramics and a carefull surgery decreased the risk os fracture. Low incidence of wear debris and biological caracteristics makes ceramics a real alternative in young or high activity patients

    Complicaciones a corto plazo de la artroplastia total primaria de cadera

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    Objetivos: Se pretende analizar las principales complicaciones a corto plazo (seis semanas) tras la Artroplastia total primaria de cadera. ;aterial y métodos: Se revisaron todos los pacientes a los que se realizó artroplastia total de cadera durante el año 2003. Las variables estudiadas fueron el índice de luxaciones, sangrado, infección, fracturas periprotésicas, complicaciones vásculo-nerviosas y mortalidad. Resultados: Obtuvimos una tasa del 4,4% de luxaciones; 1,7% de trombosis venosa profunda con un 0,87% de embolismo pulmonar, 1,7% de infecciones superficiales sin casos de infección profunda. El 14,9% de los casos necesitaron una transfusión postquirúrgica. Intraoperatoriamente observamos apertura del cálcar en el 3,5%, y fracturas periprotésicas postoperatorias en el 0,87%. No registramos complicaciones neurológicas ni mortalidad en estas primeras seis semanas del estudio. Conclusiones: La complicación más frecuente es la luxación, fundamentalmente en los casos secundarios a fractura. La trombosis venosa profunda, a èsar de la profilaxis, continúa siendo una complicación frecuente.Objectives: Our purpose was to analyze the main early complications (six weeks) after primary total hip arthroplasty. Materials and Methods: All patients who had undergone primary total hip replacement during 2003 were reviewed. The studied outcomes were the rates of dislocation, blood loss, infection, periprosthetic fractures, neural and vascular complications, and mortality. Results: Our rates were 4,4% for hip dislocation, 1,7% for deep vein thrombosis with 0,87% for pulmonary embolism, 1,7% for wound infection without cases of deep infection. 14,9% of the patients needed postoperative transfusion. We reported 3,5% fractures of the calcar during surgery and 0,87% of postoperative periprosthetic fractures. We didn ́t reported any neural complications or mortality within six weeks postoperatively. Conclusions: The most frequent complication is dislocation, mainly in cases whose underlying diagnose was hip fracture. Although prophylaxis is done, deep vein thrombosis goes on being a frequent complication

    dReDBox: Materializing a full-stack rack-scale system prototype of a next-generation disaggregated datacenter

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    Current datacenters are based on server machines, whose mainboard and hardware components form the baseline, monolithic building block that the rest of the system software, middleware and application stack are built upon. This leads to the following limitations: (a) resource proportionality of a multi-tray system is bounded by the basic building block (mainboard), (b) resource allocation to processes or virtual machines (VMs) is bounded by the available resources within the boundary of the mainboard, leading to spare resource fragmentation and inefficiencies, and (c) upgrades must be applied to each and every server even when only a specific component needs to be upgraded. The dRedBox project (Disaggregated Recursive Datacentre-in-a-Box) addresses the above limitations, and proposes the next generation, low-power, across form-factor datacenters, departing from the paradigm of the mainboard-as-a-unit and enabling the creation of function-block-as-a-unit. Hardware-level disaggregation and software-defined wiring of resources is supported by a full-fledged Type-1 hypervisor that can execute commodity virtual machines, which communicate over a low-latency and high-throughput software-defined optical network. To evaluate its novel approach, dRedBox will demonstrate application execution in the domains of network functions virtualization, infrastructure analytics, and real-time video surveillance.This work has been supported in part by EU H2020 ICTproject dRedBox, contract #687632.Peer ReviewedPostprint (author's final draft
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