Propuesta curricular de hip??tesis de progresi??n para conceptos estructurantes de ecolog??a

Resumen en ingl??s

El papel de la pr??ctica en el desarrollo de la competencia motriz infantil : la hip??tesis de la variabilidad

Se aplica la hip??tesis de la variabilidad al practicar en el aprendizaje motor infantil de la teor??a del esquema de R. Achmidt. Se estructura en tres partes. En la primera se revisan los diferentes modelos explicativos del desrrollo motor. En la segunda se analiza la Teor??a del esquema de Richard Schmidt y su hip??tesis de variabilidad al practicar. En la tercera se presentan diferentes estudios experimentales a partir de los supuestos evaluados en las otras dos partes. Se analizan diferentes aspectos de la variabilidad al practicar (parametros variados, tipo de organizaci??n). Se estudia el papel de las estrategias instructivas aunadas a la pr??ctica variable aleatoria. Investigaci??n cuantitativa y cualitativa. Los resultados apoyan la hip??tesis de Schmidt y destacan la importancia de la organizaci??n de la pr??tica variable en la infancia. Se sugieren propuestas de actuaci??n para el futuro.

Aplicaci??n del m??todo Bootstrap al contraste de hip??tesis en la investigaci??n educativa

Resumen del autor. Resumen en castellano e ingl??s. Este art??culo se incluye en el monogr??fico 'Educaci??n social'

Una hip??tesis sobre las Novelas Ejemplares

An??lisis de la afinidad y concordancia entre las Novelas Ejemplares con las obras esc??nicas de Cervantes. Se baraja la posibilidad de que las Novelas Ejemplares sean antiguas comedias de Cervantes, que m??s tarde ??ste refundi?? en prosa para adaptarlas al gusto de la ??poca.

Contraste de la hip??tesis de se??alizaci??n : una panor??mica

Resumen basado en el de la publicaci??n. Notas a pie de p??gina

Hip Hop Lab : educación a través del arte y la cultura urbanos.

Resumen basado en el de la publicación. - El articulo forma parte de una sección de la revista dedicada a creatividad y educación

Hip hop en el aula

Bibliograf??a al final del art??culo

El giro pedag??gico en la investigaci??n sobre la transferencia interling????stica : repasando las hip??tesis de interdependencia y del umbral ling????stico

Resumen basado en el de la publicaci??n

Analysis and Simulation of Transverse Random Fracture of Long Fibre Reinforced Composites

La present tesi proposa una metodología per a la simulació probabilística de la fallada de la matriu en materials compòsits reforçats amb fibres de carboni, basant-se en l'anàlisi de la distribució aleatòria de les fibres. En els primers capítols es revisa l'estat de l'art sobre modelització matemàtica de materials aleatoris, càlcul de propietats efectives i criteris de fallada transversal en materials compòsits. El primer pas en la metodologia proposada és la definició de la determinació del tamany mínim d'un Element de Volum Representatiu Estadístic (SRVE) . Aquesta determinació es du a terme analitzant el volum de fibra, les propietats elàstiques efectives, la condició de Hill, els estadístics de les components de tensió i defromació, la funció de densitat de probabilitat i les funcions estadístiques de distància entre fibres de models d'elements de la microestructura, de diferent tamany. Un cop s'ha determinat aquest tamany mínim, es comparen un model periòdic i un model aleatori, per constatar la magnitud de les diferències que s'hi observen. Es defineix, també, una metodologia per a l'anàlisi estadístic de la distribució de la fibra en el compòsit, a partir d'imatges digitals de la secció transversal. Aquest anàlisi s'aplica a quatre materials diferents. Finalment, es proposa un mètode computacional de dues escales per a simular la fallada transversal de làmines unidireccionals, que permet obtenir funcions de densitat de probabilitat per a les variables mecàniques. Es descriuen algunes aplicacions i possibilitats d'aquest mètode i es comparen els resultats obtinguts de la simulació amb valors experimentals.

El cambio que rima. Creando espacios alternativos de contestación cultural desde el hip hop. Estudio del caso de raperos de El Alto y La Paz

A través de este trabajo se pretende comprender cómo se construye un espacio de contestación cultural y político desde una expresión artística como rap, que para aquellos que son sus seguidores, es parte de la “cultura Hip Hop”. Para cumplir este objetivo, el presente estudio desarrolla en el primer capítulo una recapitulación metodológica del camino trazado, es decir la explicación de las técnicas, herramientas y enfoques desde los que se trataron el tema, y por qué éstas se eligieron. En el segundo capítulo se da una breve reseña sobre el movimiento de rap a nivel mundial y nacional para luego concretar el desarrollo del movimiento en La Paz y El Alto. Finalmente, el tercer capítulo pretende mostrar el camino que une a los raperos con el público. Este es el eje del último capítulo, pues a través del presente documento, se plantea la relación entre músicos, activistas o artistas, con un público determinado. Esta tesis es una forma de entender cómo jóvenes de distinta procedencia y visiones sobre la vida, actúan en su sociedad y hablan de su realidad creando espacios de contestación que interpelan y responden a hechos concretos que afectan su cotidianeidad.

Proteomic analysis of resting and thrombin-stimulated platelets reveals the translocation and functional relevance of HIP-55 in platelets

The platelet surface is a dynamic interface that changes rapidly in response to stimuli to coordinate the formation of thrombi at sites of vascular injury. Tight control is essential as loss of organisation may result in the inappropriate formation of thrombi (thrombosis) or excessive bleeding. In this paper we describe the comparative analysis of resting and thrombin-stimulated platelet membrane proteomes and associated proteins to identify proteins important to platelet function. Surface proteins were labelled using a biotin tag and isolated by NeurtrAvidin affinity chromatography. Liquid phase IEF and SDS-PAGE were used to separate proteins, and bands of increased intensity in the stimulated platelet fractions were digested and identified by FT-ICR mass spectrometry. Novel proteins were identified along with proteins known to be translocated to the platelet surface. Furthermore, many platelet proteins revealed changes in location associated with function, including G6B and Hip-55. HIP-55 is an SH3-binding protein important in T-cell receptor signalling. Further analysis of HIP-55 revealed that this adaptor protein becomes increasingly associated with both Syk and integrin beta 3 upon platelet activation. Analysis of HIP-55 deficient platelets revealed reduced fibrinogen binding upon thrombin stimulation, suggesting HIP-55 to be an important regulator of platelet function.

Fracture incidence in relation to the pattern of use of hormone therapy in postmenopausal women

Context: Evidence is limited on the effects of different patterns of use of postmenopausal hormone therapy on fracture incidence and particularly on the effects of ceasing use. Objective: To investigate the effect of different patterns of hormone therapy use on fracture incidence. Design, Setting, and Participants: Prospective study of 138737 postmenopausal women aged 50 to 69 years recruited from the UK general population in 19961998 (the Million Women Study) and followed up for 1.9 to 3.9 years (average, 2.8 years) for fracture incidence. Main Outcome Measure: Adjusted relative risk (RR) for incident fracture (except fracture of the fingers, toes, and ribs) in hormone therapy users compared with never users at baseline. Results: A total of 5197 women (3.7%) reported 1 or more fractures, 79% resulting from falls. Current users of hormone therapy at baseline had a significantly reduced incidence of fracture (RR, 0.62; 95% confidence interval [CI], 0.58-0.66; P<.001). This protection was evident soon after hormone therapy began, and the RR decreased with increasing duration of use (P=.001). Among current users at baseline the RR of fracture did not vary significantly according to whether estrogen-only, estrogen-progestin, or other types of hormones were used (RR [95% CI], 0.64 [0.58-0.71], 0.58 [0.53-0.64], and 0.67 [0.56-0.80], respectively; P=19), nor did it vary significantly according to estrogen dose or estrogen or progestin constituents. The RR associated with current use of hormone therapy did not vary significantly according to 11 personal characteristics of study participants, including their age at menopause, body mass index, and physical activity. Past users of hormone therapy at baseline experienced no significant protection against fractures (RR, 1.07; 95% CI, 0.99-1.15); incidence rates returned to those of never-users within about a year of ceasing use. Conclusions: All types of hormone therapy studied confer substantial protection against fracture while they are used. This protection appears rapidly after use commences and wears off rapidly after use ceases. The older women are, the greater is their absolute reduction in fracture incidence while using hormone therapy.

Modelling metal cutting using modern ductile fracture mechanics: Quantitative explanations for some longstanding problems

The assumption that negligible work is involved in the formation of new surfaces in the machining of ductile metals, is re-examined in the light of both current Finite Element Method (FEM) simulations of cutting and modern ductile fracture mechanics. The work associated with separation criteria in FEM models is shown to be in the kJ/m2 range rather than the few J/m2 of the surface energy (surface tension) employed by Shaw in his pioneering study of 1954 following which consideration of surface work has been omitted from analyses of metal cutting. The much greater values of surface specific work are not surprising in terms of ductile fracture mechanics where kJ/m2 values of fracture toughness are typical of the ductile metals involved in machining studies. This paper shows that when even the simple Ernst–Merchant analysis is generalised to include significant surface work, many of the experimental observations for which traditional ‘plasticity and friction only’ analyses seem to have no quantitative explanation, are now given meaning. In particular, the primary shear plane angle φ becomes material-dependent. The experimental increase of φ up to a saturated level, as the uncut chip thickness is increased, is predicted. The positive intercepts found in plots of cutting force vs. depth of cut, and in plots of force resolved along the primary shear plane vs. area of shear plane, are shown to be measures of the specific surface work. It is demonstrated that neglect of these intercepts in cutting analyses is the reason why anomalously high values of shear yield stress are derived at those very small uncut chip thicknesses at which the so-called size effect becomes evident. The material toughness/strength ratio, combined with the depth of cut to form a non-dimensional parameter, is shown to control ductile cutting mechanics. The toughness/strength ratio of a given material will change with rate, temperature, and thermomechanical treatment and the influence of such changes, together with changes in depth of cut, on the character of machining is discussed. Strength or hardness alone is insufficient to describe machining. The failure of the Ernst–Merchant theory seems less to do with problems of uniqueness and the validity of minimum work, and more to do with the problem not being properly posed. The new analysis compares favourably and consistently with the wide body of experimental results available in the literature. Why considerable progress in the understanding of metal cutting has been achieved without reference to significant surface work is also discussed.