Visualización del concepto de exactitud en integración numérica

En los últimos tiempos, el estudio de la visualización en el pensamiento matemático es objeto de numerosas investigaciones, en parte, posiblemente, debido al surgimiento de la computadora como un recurso didáctico para la comprensión de conceptos matemáticos. Este trabajo tiene como objetivo reflexionar sobre la importancia de poder relacionar e interpretar imágenes visuales (utilizando manipulables virtuales) con la información que está dada en forma simbólica. Presentamos una propuesta didáctica para la comprensión del concepto de exactitud del método de Simpson utilizándose la interfase gráfica de MATLAB, GUI (graphical user interface), la cual fue puesta en práctica con alumnos de la asignatura Cálculo Numérico de la carrera Ingeniería Electrónica. El uso reflexivo y creativo de las nuevas tecnologías permite dar un significado concreto a las nociones matemáticas por lo que el diseño de nuevos materiales utilizando esta nueva metodología, donde muestren el uso efectivo en el aula, es sumamente importante. Del análisis realizado en la evaluación escrita y en el examen parcial de la asignatura, esta nueva metodología permite afianzar la comprensión y fijar el concepto con mayor facilidad a los que se someten a la enseñanza predominantemente algorítmica

Una propuesta didáctica utilizando las nuevas tecnologías para la enseñanza de la integral como límite de sucesiones

En este trabajo presentamos una propuesta didáctica para la enseñanza del tema Integral definida para alumnos de primer año de las carreras de Ingeniería en la asignatura Análisis matemático I. En esta secuencia utilizamos la interfase gráfica de MATLAB, GUI (graphical user interface). El concepto de integral definida es utilizado, para determinar el valor del área limitada por curvas y rectas. Tradicionalmente, para comenzar a explicar este concepto, el profesor, dibuja en el pizarrón la zona a determinar su área, subdividiendo los intervalos y encontrando el área buscada, para lo cual introduce el concepto de integral definida. En la secuencia que presentamos, es el alumno, utilizando la computadora, quien va subdividiendo el intervalo, visualizando el área buscada

Gravitational Waves at Strong Coupling from an Effective Action

Using a holographic derivation of a quantum effective action for a scalar operator at strong coupling, we compute quasiequilibrium parameters relevant for the gravitational wave signal from a first-order phase transition in a simple dual model. We discuss how the parameters of the phase transition vary with the effective number of degrees of freedom of the dual field theory. Our model can produce an observable signal at LISA if the critical temperature is around a TeV, in a parameter region where the field theory has an approximate conformal symmetry.Peer reviewe

Effective actions and bubble nucleation from holography

We discuss the computation of the quantum effective action of strongly interacting field theories using holographic duality and its use to determine quasiequilibrium parameters of first-order phase transitions relevant for gravitational wave production. A particularly simple holographic model is introduced, containing only the metric and a free massive scalar field. Despite the simplicity, the model contains a rich phase diagram, including first-order phase transitions at nonzero temperature, due to various multitrace deformations. We obtain the leading terms in the effective action from homogeneous black brane solutions in the gravity dual and linearized perturbations around them. We then employ the effective action to construct bubble and domain wall solutions in the field theory side and study their properties. In particular, we show how the scaling of the effective action with the effective number of degrees of freedom of the quantum field theory determines the corresponding scaling of gravitational wave parameters.Peer reviewe

Aproximación del comportamiento de ladrillos cerámicos huecos mediante métodos numéricos

En la provincia de Misiones, Argentina, se destaca el uso frecuente de mampuestosconocidos como Ladrillos Cerámicos Huecos (LCH), los cuales son de fabricación industrial,moldeados con máquinas extrusoras, cocidos en hornos continuos. En términos de comportamientomecánico y estructural es un elemento de rotura frágil, el cual suele estar solicitado en forma global acompresión dentro de las mamposterías que conforma, con valores de resistencia que dependen devarios factores propios de su proceso de fabricación. En cuanto a su geometría es destacable laaparente interacción entre las paredes internas y externas que conforman una estructura de marcos. Elobjetivo del presente trabajo es analizar mediante una herramienta de simulación numérica, elcomportamiento mecánico de los mampuestos de la región, en forma aislada, considerando lasdiferentes variables que intervienen en su forma y composición material. Para ello, los ladrilloscerámicos individuales son modelados a través del método de los elementos finitos en el softwareSAP 2000 versión 14.1.0. El material es considerado según propiedades mecánicas y geométricas queson obtenidas a través de ensayos experimentales normalizados. Con los resultados experimentales dedeformaciones y resistencia a compresión se calibra el modelo numérico, con el que se obtieneinformación sobre el comportamiento de interacción entre las paredes horizontales y verticales delladrillo a efectos de poder avanzar en la formulación de macro modelos conformados por elementosfinitos de área.Fil: Duarte, Javier Alberto. Universidad Nacional de Misiones; ArgentinaFil: Detke, Fernando Rubén. Universidad Nacional de Misiones; ArgentinaFil: Reinert, Hugo Orlando. Universidad Nacional de Misiones; ArgentinaFil: Garcia, Diego Alberto. Universidad Nacional de Misiones; Argentina. Comisión Nacional de Investigación Científica y Tecnológica; ChileFil: Ares, Alicia Esther. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Möller, Oscar. Universidad Nacional de Rosario; Argentin

Transcultural adaptation and validation of the “Hip and Knee” questionnaire into Spanish

Journal Article; Research Support, Non-U.S. Gov't;BACKGROUND The purpose of the present study is to translate and validate the "Hip and Knee Outcomes Questionnaire", developed in English, into Spanish. The 'Hip and Knee Outcomes Questionnaire is a questionnaire planned to evaluate the impact in quality of life of any problem related to the human musculoskeletal system. 10 scientific associations developed it. METHODS The questionnaire underwent a validated translation/retro-translation process. Patients undergoing primary knee arthroplasty, before and six months postoperative, tested the final version in Spanish. Psychometric properties of feasibility, reliability, validity and sensitivity to change were assessed. Convergent validity with SF-36 and WOMAC questionnaires was evaluated. RESULTS 316 patients were included. Feasibility: a high number of missing items in questions 3, 4 and 5 were observed. The number of patients with a missing item was 171 (51.35%) in the preoperative visit and 139 (44.0%) at the postoperative. Internal validity: revision of coefficients in the item-rest correlation recommended removing question 6 during the preoperative visit (coefficient <0.20). Convergent validity: coefficients of correlation with WOMAC and SF-36 scales confirm the questionnaire's validity. Sensitivity to change: statistically significant differences were found between the mean scores of the first visit compared to the postoperative. CONCLUSION The proposed translation to Spanish of the 'Hip and Knee Questionnaire' is found to be reliable, valid and sensible to changes produced at the clinical practice of patients undergoing primary knee arthroplasty. However, some changes at the completion instructions are recommended. LEVEL OF EVIDENCE Level I. Prognostic study.Ye

Blood Transfusion in Knee Arthroplasty

Orthopedic surgery is one of most blood-consuming surgical specialties since it is associated with a significant preoperative hemorrhage requiring frequent allogeneic blood transfusions. A special mention needs to be done to hip and knee arthroplasty, complex rachis arthrodesis and tumor-pathology removal. The intervention on older and higher-risk patients has raised the demand on allogeneic blood to such levels that even Blood Banks are unable to attend. Besides the high cost, using allogeneic blood has its risks, such as immunosuppression, patient’s wrong identification, transfusion reactions or the possibility of infectious disease transmission. This imbalance between blood demand and availability, together with the awareness about potential risks of blood transfusions and the continuous advances both in technology and pharmaceutics, should lead us to extreme changes in transfusion politics; developing a series of therapeutic measures to reduce blood transfusion to minimum, leaving its use only when it is strictly necessary, especially in scheduled surger

Sitagliptin reduces cardiac apoptosis, hypertrophy and fibrosis primarily by insulin-dependent mechanisms in experimental type-II diabetes. Potential roles of GLP-1 isoforms

Background:Myocardial fibrosis is a key process in diabetic cardiomyopathy. However, their underlying mechanisms have not been elucidated, leading to a lack of therapy. The glucagon-like peptide-1 (GLP-1) enhancer, sitagliptin, reduces hyperglycemia but may also trigger direct effects on the heart.Methods:Goto-Kakizaki (GK) rats developed type-II diabetes and received sitagliptin, an anti-hyperglycemic drug (metformin) or vehicle (n=10, each). After cardiac structure and function assessment, plasma and left ventricles were isolated for biochemical studies. Cultured cardiomyocytes and fibroblasts were used for in vitro assays.Results:Untreated GK rats exhibited hyperglycemia, hyperlipidemia, plasma GLP-1 decrease, and cardiac cell-death, hypertrophy, fibrosis and prolonged deceleration time. Moreover, cardiac pro-apoptotic/necrotic, hypertrophic and fibrotic factors were up-regulated. Importantly, both sitagliptin and metformin lessened all these parameters. In cultured cardiomyocytes and cardiac fibroblasts, high-concentration of palmitate or glucose induced cell-death, hypertrophy and fibrosis. Interestingly, GLP-1 and its insulinotropic-inactive metabolite, GLP-1(9-36), alleviated these responses. In addition, despite a specific GLP-1 receptor was only detected in cardiomyocytes, GLP-1 isoforms attenuated the pro-fibrotic expression in cardiomyocytes and fibroblasts. In addition, GLP-1 receptor signalling may be linked to PPARδ activation, and metformin may also exhibit anti-apoptotic/necrotic and anti-fibrotic direct effects in cardiac cells.Conclusions:Sitagliptin, via GLP-1 stabilization, promoted cardioprotection in type-II diabetic hearts primarily by limiting hyperglycemia e hyperlipidemia. However, GLP-1 and GLP-1(9-36) promoted survival and anti-hypertrophic/fibrotic effects on cultured cardiac cells, suggesting cell-autonomous cardioprotective actionsThis work was supported by national funding from Ministerio de Educación y Ciencia (SAF2009-08367), Comunidad de Madrid (CCG10-UAM/ BIO-5289), and a unrestricted grant from by Merck/MS

Detection and genetic characterization of enteric viruses in diarrhoea outbreaks from swine farms in Spain

Background The aim of this work was to study the prevalence and distribution of Porcine astrovirus (PAstV), Porcine kobuvirus (PKoV), Porcine torovirus (PToV), Mammalian orthoreovirus (MRV) and Porcine mastadenovirus (PAdV) as well as their association with widely recognized virus that cause diarrhoea in swine such as coronavirus (CoVs) and rotavi‑ rus (RVs) in diarrhoea outbreaks from Spanish swine farms. Furthermore, a selection of the viral strains was genetically characterized. Results PAstV, PKoV, PToV, MRV and PAdV were frequently detected. Particularly, PAstV and PKoV were detected in almost 50% and 30% of the investigated farms, respectively, with an age-dependent distribution; PAstV was mainly detected in postweaning and fattening pigs, while PKoV was more frequent in sucking piglets. Viral co-infections were detected in almost half of the outbreaks, combining CoVs, RVs and the viruses studied, with a maximum of 5 dif‑ ferent viral species reported in three investigated farms. Using a next generation sequencing approach, we obtained a total of 24 ARN viral genomes (>90% genome sequence), characterizing for frst time the full genome of circulating strains of PAstV2, PAstV4, PAstV5 and PToV on Spanish farms. Phylogenetic analyses showed that PAstV, PKoV and PToV from Spanish swine farms clustered together with isolates of the same viral species from neighboring pig producing countries. Conclusions Although further studies to evaluate the role of these enteric viruses in diarrhoea outbreaks are required, their wide distribution and frequent association in co-infections cannot be disregard. Hence, their inclusion into routine diagnostic panels for diarrhoea in swine should be considered. Keywords Swine, Multiplex RT-PCR, Phylogenetic analysis, Porcine astrovirus, Porcine kobuvirus, Porcine torovirus, Mammalian orthoreovirus, Porcine mastadenovirusThis work was supported by the program of the National Institute of Agricultural and Food Research and Technology (INIA project E-RTA2015-0003-C02-01 and E-RTA2015-0003-C02-02) of Spanish Government. H. Puente, O. Mencía-Ares, L. Pérez-Pérez, M. Cortey and H. Argüello were supported by Spanish Government (FPU17/00466, FPU16/03485, PRE2020-093762, RYC-2015-1715-4 and BEAGAL- 18-106, respectively) and M. Gómez-García by Junta de Castilla & León (LE131-18)info:eu-repo/semantics/publishedVersio

Ski Lesions Around the Knee: A Literature Review

Ski is a popular sports practiced worldwide although it is considered a high-risk sports with high incidence of injuries. A common place for injuries is the knee, with a wide range from knee sprains to complex ligamentous injuries to fractures. In this chapter, we made a search in PubMed using the words “knee” and “ski.” Later, we selected those articles according to the inclusion criteria. When reviewing the literature, we found that the most common place for a ski-related injury is the knee, with knee sprains and ACL lesions being the most common diagnosis in the latter years with a decreasing incidence of tibia fractures. We could also analyze the risk factors different authors have found, for professional athletes and for recreational skiers. In conclusion, the ACL lesion in the skier presents a high incidence, which suggests an effort should be made to prevent it