Documento mediante el cual Julio Uribe S., explica a la opinión pública acerca de la forma en que se han adelantado las negociaciones entre el Gobierno nacional y particulares de Europa, con el fin de conseguir un empréstito que permita la finalización de la construcción del ferrocarril de Antioquia. El impreso aparece acompañado por una serie de documentos que muestran cómo Uribe ha realizado las diferentes negociaciones, con el fin de que tanto particulares como agencias de prensa estén al tanto de las garantías y transparencia del proceso.

If architecture has succeeded the natural impulse of evolution and demonstrated its everchanging creative power, urbanism has challenged its operationality by revealing a logic that surpasses any established concepts within the field. New urbanisms today are understood by weakening public life, changing the nature of the streets and modifying the human scale. Furthermore, the emergent post-urban life appears unmanageable due to conditions never diagnosed before: edge cities, peripheries, nodality and disarticulation seem problematic to conceptualize. What is it about the challenge of architecture capable to deploy a logic that drives urban design with a certain direction? Architecture can expand its potential design approaches through the investigation of its own rationality in order to find new sources that intersect emerging urban landscapes. The façade performs as a critical surface that articulates urban affects and provides a positive understanding of the street-grid as a persistent and flexible planning instrument along time. If the plan is not sufficient anymore, by securing its spatial hierarchies the building skin becomes significant to a contemporary discussion where architecture gains an instrument to overcome the difference. The dialogue amongst architectural design process is not reducible to a fixed set of values but to opening up its own disciplinary boundaries. It intends to rethink these borders in new terms utilizing few notions and examples that have proven as techniques of formal stability within architecture, as opposed to the diffuse and complex transformational processes of the city. Paradoxically, it is inside architecture where non-static surfaces of composition open the field to creative processes, since they are by nature given to experimentation.

Abstract: Cinema has developed into an industry of production and a medium channeling the social and cultural contexts it is made in. In academia, it has been consolidated as a field and form of knowledge, with formal professions in post-secondary education programs. It has also been an asset in secondary education to languages, literature, arts and the humanities. But with schools either offering it or not (unlike said disciplines) as a separate key subject, does the study and practice of cinema itself contribute to the young learner’s integral human development? Situating movies as a mediation for cultural transmission, the affirmative is observed, as the exercises of criticism and creation associated with the moving image artform further the cognizance and expressiveness of a person. A review of cinema and media scholarship, particularly early film theory and history, will allow the tracking of notions regarding the educational potential of motion picture viewing and creation, arriving at an overview of it on learners in their youth. Then, an analysis of film practice literature to align it with learning theories and the cognitive and communicative dimensions of human development shall serve as examples of how the field itself can inform the design of high school cinema courses. Resumen: El cine se ha desarrollado como una industria de producción y un medio que canaliza los contextos sociales y culturales en los que se realiza. En la academia, ha sido consolidado como un campo y forma de conocimiento, con profesiones formales y programas de educación post-secundaria. También ha sido un soporte en la educación secundaria a los idiomas, la literatura, las artes y las humanidades. Empero, con los colegios ofreciéndolo o no (a diferencia de las disciplinas mencionadas) como una materia clave por separado, ¿contribuye el estudio y la práctica del cine como tal al desarrollo humano integral del joven aprendiz? Situando las películas como una mediación para la transmisión cultural, se observa lo afirmativo, dado que los ejercicios de crítica académica y creación asociados con el arte de la imagen en movimiento profundizan el conocer y la expresividad de una persona. Una revisión de literatura académica en cine y medios, en particular de la teoría e historia temprana del cine, permitirá el seguimiento de nociones sobre el potencial educativo de ver y crear películas, llegando a una descripción general de lo anterior en aprendices en su juventud. Luego, un análisis de escritos sobre la práctica del cine, con miras a alinearla con teorías del aprendizaje y las dimensiones cognitiva y afectiva del desarrollo humano, servirán como ejemplos de cómo el campo como tal puede informar el diseño de cursos en cine en bachillerato alto.

Flip chip interconnection design and process capability has been extended with the use of copper pillar, specially for finer pitches, beyond what was possible with area array and standard C4 reflow and solder bumps. Many trends in device packaging are fueling this trend, specially the needs for thin packaging, increased function integration, challenging thermal, mechanical and physical specifications. In terms of processing, devices using Cu Pillar are most commonly assembled using thermo-compression bonding due to sizable challenges in extending the conventional mass reflow solution, typical for solder bumps. TC is specially recommended for handling very thin die in sparse or peripheral bump layouts, which are a predominant share of all devices converting to Cu pillar, where a bonding head is used to both hold the die flat and in true alignment with the substrate while supplying the thermal energy necessary to complete the interconnection. This process most often also requires the use of a non-conductive paste/film for stress absorption in recognition to the fact that underfill materials have great limitations in filling the underdie cavity. In this paper, we explore avenues to extend the current processing envelope for Cu pillar bumped devices using C4 reflow. Benefits of this approach are shown as decreased cost of ownership for materials, lower fixed costs due to using mostly depreciated equipment. Yet, challenges in defining new design rules, reformulating materials and extending process flows are among some of the barriers for further adoption of this solution in production.

Abstract: The present study aims to create a patient-specific hand model to simulate the passive rehabilitation on the index finger, quantifying the flexor digitorum profundus (FDP) tendon excursion and the stress experienced during simulated flexion. The computational model used in this analysis was created from an unknown patient dataset available in the Embodi3d online library. The segmentation, three-dimensional reconstruction, and modeling of the structures involved were performed using Materialise Mimics and Rhino3D. The FDP tendon excursion and stress values present in the model were calculated in the ANSYS environment. Based on the finite-element simulation, the FDP tendon presents an excursion of 10.1 mm during passive postoperative flexion. The highest-stress values were observed between the pulleys-FDP tendon contact surfaces. In particular, the pulley A1 exhibited the máximum principal stress of the model with a 58.7 MPa. The pulley A3 showed the same stress distribution pattern that A1 Pulley, but with the lowest values. The FDP Tendon excursión obtained is consistent with the results reported in the literature, which vary from 8 to 11 mm. The stress values found in the model explain the importance of the pulley mechanism keeping the FDP tendon attached to the finger bone during the range of motion experienced. The silico model proposed may potentially be used in the assessment of new medical device proposals in the field of hand reconstructive surgery.

Hollow steel sections are considered a convenient element shape in civil engineering due to their architectural and structural advantages. Combination of hollow section columns with open section beams are structurally more efficient. However, this configuration use is limited due to the complexity of its connection. Blind fasteners have been developed to overcome the problem caused by the limited accessibility to the inner part of the hollow steel sections to tight a standard bolt and its nut. Based on the available literature, a novel blind fastener named the Extended Hollo-Bolt (EHB) is considered to offer a promising configuration for moment-resisting joints between open and concrete filled hollow sections. However, the EHB connection behaviour is not fully understood and therefore specific design approaches are lacking. This work investigates the combined failure mode of the connection by means of a Finite Element model validated against previous laboratory test results and the effect of the column thickness through a parametric study. An analytical model is also proposed. A non-linear numerical model was created in Abaqus (version 6.15) which simulates a single row of two EHB in tension. The developed FE model was able to represent the column and bolt failure modes in agreement with the experimental results and predict the behaviour of the connection when a combined failure occurs. Three numerical analyses were carried out using commercial column face thicknesses to evaluate the effect of the column slenderness ratio on the stiffness of the connection when subjected to a pull-out force. The main contribution of this work is the FE model and the proposed analytical strength and stiffness component models for the combined failure of the EHB component. Perfiles de acero tubulares son preferidos en construcciones civiles debido a sus ventajas arquitectónicas y estructurales, además, la combinación de columnas tubulares con vigas hechas con perfiles abiertos (formas I o H) es estructuralmente más eficiente que estructuras que usan solo perfiles abiertos. Sin embargo, el uso de esta configuración es limitado ya que las conexiones entre estos miembros estructurales son complejas. Los llamados pernos ciegos fueron desarrollados para superar los problemas causados por la falta de accesibilidad al interior de los perfiles tubulares para atornillar un perno con tuerca estándar. Un novedoso tipo de perno llamado Hollo-Bolt (del inglés Hollow: hueco y bolt: tornillo) extendido (EHB) ha mostrado potencial para ser usado en conexiones rígidas entre columnas tubulares y vigas con perfiles abiertos. Sin embargo, el comportamiento del EHB no ha sido completamente entendido y por lo tanto no existen guías de diseño que permitan usarlo en la industria. El presente trabajo investiga el tipo de falla combinada del perno por medio de un modelo de elementos finitos validado con resultados previos de ensayos de laboratorio, además, estudia los efectos producidos al utilizar diferentes espesores en la columna tubular. Finalmente, un modelo analítico es propuesto. Un modelo no lineal fue desarrollado en el programa Abaqus para simular una fila de dos pernos EHB bajo tensión. El modelo desarrollado captura el comportamiento de los dos tipos de fallas encontrados en la literatura: tornillo en tensión y columna en flexión, y además predice el comportamiento cuando una falla combinada puede ocurrir. En total, tres análisis numéricos fueron llevados a cabo con secciones tubulares comerciales para evaluar el efecto del espesor de la columna en la rigidez y resistencia de la conexión. La principal contribución de este trabajo de investigación es un modelo analítico para calcular la rigidez y resistencia de este tipo de conexión compuesta. Distinción: Tesis sobresaliente. Mejor graduado de maestría en ingeniería estructural.

Recent technological developments in mechanical investigation techniques and nondestructive monitoring of masonry buildings provide today an amount of information, unthinkable up until yesterday. Likewise the techniques of automated laser survey allow a rapid and precise definition of the geometry of a building, with a level of detail never previously reached. On the other hand, the applications to the modeling of complex masonry historical structures are not as widespread, and constitute an interesting subject of research. Despite the fact that numerical modeling techniques based on the finite element method have progressed considerably, and the computing power available is constantly growing. The difficulties that are encountered are manifold, and reside especially on the absence of well consolidated procedures for the definition of the model and for the management of uncertainties. The Asinelli Tower in Bologna is taken as a case study to define a general methodology for the analysis of historical masonry towers. Using the finite element code DIANA (TNO Diana, Netherlands) the difficulties that are typically encountered in building models of increasing complexity are addressed, proposing a general procedure. The study of the tower, although not directed to the formulation of an explicit judgment on the structural stability, has led to the formulation of an anisotropic cracked masonry model, capable of representing the dynamic behavior of the tower with greater efficiency compared to what is available in the scientific literature.

Abstract: The remarkable high strength-to-weight ratio of bamboo and the recent innovations and development of laminated bamboo products has enabled the potential for new larger and taller structural bamboo applications. However, there is little understanding of the behaviour and performance of bamboo structures during and after a fire. To date, bamboo has been used widely in low-rise constructions where structural integrity during and after a fire does not pose a risk to the life safety of occupants, fire service intervention, and significant impact on property protection or business continuity. Nevertheless, a comprehensive understanding of the structural fire performance is crucial if bamboo is to be widely used in the construction of mid- and high-rise load-bearing structures. An extensive literature review on the fire performance of bamboo structures shown herein identifies that novel fire testing methods were needed to investigate the mechanical response of bamboo, primarily to study the reduction in the strength and stiffness at elevated temperatures. Past research outcomes have evidenced the need for constitutive stress-strain models to describe the mechanical behaviour of bamboo at elevated temperatures, as well as numerical models to predict the response of the bamboo loadbearing members during and after a fire. Several small and bench-scale experimental studies were conducted to understand the reduction in the mechanical properties of bamboo at elevated temperatures. Compressive tests were performed for round and laminated bamboo for test samples at temperatures between ambient and 250ºC. Round bamboo strips were tested in tension to understand the reduction in the tensile strength at elevated temperatures. A dynamic mechanical analysis of bamboo strips was carried out to investigate the decrease in the modulus of elasticity at elevated temperatures, and to compare this against the results of bench-scale tests to analyse the effect of a different test set-up and heat transfer scenario. With the experimental results of the reduction of the compressive and tensile strength of bamboo, as well as the modulus of elasticity, constitutive stress-strain models were proposed to correlate the stress-and strain relationship at elevated temperatures. Equations for the reduction factors of strength and modulus of elasticity were presented, as well as stress-strain curves. The linear elastic behaviour of bamboo under tension and compression, and the elastoplastic behaviour under compression were analysed to quantify the effects of elevated temperatures. Another series of experiments were conducted to investigate the performance of laminated bamboo beams exposed to fire. The bamboo beams were loaded at different stress-levels whilst exposed to a constant indecent heat flux. The beams were fully instrumented to measure the loss of cross-section, the strain profiles, and the deflections at the mid-span during the heating exposure. Finally, a numerical model combining the thermal performance, and the mechanical behaviour of bamboo at elevated temperatures was developed to predict the stress-strain profiles, the deflection, and the bending capacity of bamboo beams during a fire. The results of the numerical model were compared against the results obtained from the experimental tests, and the model showed a good agreement with the experimental results. The proposed framework shows that structural analysis can be carried out if heat transfer analysis and constitutive stress-strain models are available to predict the thermomechanical response of laminated bamboo beams. Findings from this work provide a good understanding of the reduction on the strength and elasticity of bamboo at elevated temperatures. These results will enable predictions to be made for the bending capacity of bamboo beams during a fire, and they will constitute the basis for designing fire-safe bamboo structures.

Abstract: The conservation of migratory species poses significant challenges that may be countered by detailed knowledge about the sites used by migrants throughout the annual cycle. We present the rst GPS-tracking data on the migration of declining Caspian terns Hydroprogne caspia breeding in the Baltic Sea. For 39 Caspian terns from colonies along a latitudinal gradient from 57 to 65°N, we identified key migratory routes, stopovers and wintering areas. In autumn these seabirds migrated using coastal and freshwater stopovers along six routes to reach their wintering areas across the Sahel, the Nile River Basin and the southern Iberian Peninsula. In spring, adults returned to the breeding grounds in the Baltic using a time optimizing strategy by reducing time at stopover by 78%, whereas most subadults remained sedentary and some performed only partial return migrations. Of the stopover sites used in both seasons, 58% are protected and have a reported management plan. Conservation strategies in wintering areas, stopover sites that are not protected or had not been previously recognized, and the inclusion of the species in important migratory yways across Europe and Africa will be important to prevent further population declines of a species that depends on aquatic habitats.

Abstract: Recent research suggests that intergovernmental grants, own-source revenues, and changes in government investment play a crucial role in helping local governments in advanced economies to adjust their fiscal positions in response to budget shocks. Little is known, however, about the dynamic of local fiscal adjustments in emerging economies, and there are reasons to expect distinct fiscal stabilization patterns, for instance, due to lower fiscal capacity. A panel dataset of more than 900 municipalities in Colombia shows that in line with some of the results for developed countries: (1) intergovernmental grants react significantly to increases in government spending; (2) the response of own-source revenues to innovations in government spending in large cities is higher than in the small ones; (3) government investment is highly volatile and responds to innovations in all other budgetary components; and (4) there is no empirical evidence of a reduction in fiscal effort following increases in intergovernmental grants.