6,160 research outputs found
Las medidas cautelares en el arbitraje nacional a partir de la Ley 1563 de 2012
Trabajo de investigaciónLa Ley 1563 de 2012 facultó a los árbitros para decretar una amplia gama de medidas cautelares nominadas e innominadas; sin embargo, en la práctica se hace poco uso de ellas, poniendo en riesgo su eficacia, así como la propia tutela judicial efectiva, por lo cual se pretende identificar las razones por las cuales no solicitan o no se decretan.PregradoAbogad
A biogeographical evaluation of the vegetation landscapes of las Bardenas Reales in Navarre in accordance with the LANBIOEVA methodology
El territorio de las Bardenas de Navarra configura uno de los paisajes más originales e infrecuentes de Europa. El relieve tabular estructural del Terciario ha sido modelado mayoritariamente en forma de badlands en un contexto climático de precipitaciones escasas y concentradas, temperaturas rigurosas tanto en invierno como en verano y vientos persistentes. Este contexto ambiental configura un paisaje vegetal de carácter estepario y con ciertas reminiscencias de zonas áridas o semiáridas. Es precisamente este interés el que nos lleva a caracterizar y valorar sus agrupaciones vegetales a través
de la metodología LANBIOEVA. El método se aplica de forma sistemática de manera que las evaluaciones para cada uno de los criterios y subcriterios puedan ser comparadas con las obtenidas durante más de 25 años en otros ámbitos y formaciones a escala global. Destacan con valoraciones altas el pinar de Pinus halepensis y, sobre todo, el carrascal de Quercus ilex ssp. rotundifolia. Por su parte, las puntuaciones más bajas se registran para el coscojar de Quercus coccifera.The territory of Bardenas de Navarra is one of the most original and uncommon in Europe. The structural tabular topography of the Tertiary age has been sculpted mostly into badlands in climatic conditions of low and concentrated rainfall, severe temperatures both in winter as in summer and persistent winds. This environmental context configures a steppe-type vegetal landscape reminiscent of arid or semi-arid areas. It is that interest that leads us to characterize and to assess its vegetal landscape using the LANBIOEVA methodology. This method is applied, in a systematic manner, to
those vegetal landscapes in order to obtain the data about each assessment criterion and these to be compared with other data obtained for over twenty years in other formations and areas at a global level. The Aleppo pine forest (Pinus halepensis) stands out for its high values and also does, especially, oak woods (Quercus rotundifolia). The lowest scores are recorded for the Kermes (Quercus coccifera)
Synthesis, characterization and performance of robust poison-resistant ultrathin film yttria stabilized zirconia – nickel anodes for application in solid electrolyte fuel cells
We report on the synthesis of undoped ∼5 μm YSZ-Ni porous thin films prepared by reactive pulsed DC magnetron sputtering at an oblique angle of incidence. Pre-calcination of the amorphous unmodified precursor layers followed by reduction produces a film consisting of uniformly distributed tilted columnar aggregates having extensive three-phase boundaries and favorable gas diffusion characteristics. Similarly prepared films doped with 1.2 at.% Au are also porous and contain highly dispersed gold present as Ni-Au alloy particles whose surfaces are strongly enriched with Au. With hydrogen as fuel, the performance of the undoped thin film anodes is comparable to that of 10–20 times thicker typical commercial anodes. With a 1:1 steam/carbon feed, the un-doped anode cell current rapidly falls to zero after 60 h. In striking contrast, the initial performance of the Au-doped anode is much higher and remains unaffected after 170 h. Under deliberately harsh conditions the performance of the Au-doped anodes decreases progressively, almost certainly due to carbon deposition. Even so, the cell maintains some activity after 3 days operation in dramatic contrast with the un-doped anode, which stops working after only three hours of use. The implications and possible practical application of these findings are discussed.European Union 298300Ministerio de Economía y Competitividad MAT2013‐40852R, 201560E05
A microfluidic platform for combinatorial synthesis and optimization of targeted polymeric nanoparticles for cancer therapy
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, February 2013."November 2012." Cataloged from PDF version of thesis.Includes bibliographical references.The use of nanotechnology to engineer drug delivery vehicles comprised of controlled release polymers with targeting molecules has the potential to revolutionize cancer therapy, among other diseases. Although a myriad of nanotherapeutics have been developed at the bench side, many of them stay at the research stage due to their complexity and difficulty in their optimization. A key challenge for optimization of nanoparticles (NPs) for drug delivery is the ability to systematically and combinatorially create and screen libraries of NPs with distinct physicochemical properties, from which promising formulations can be moved forward to preclinical and clinical studies. In this work, the development of a controlled method to synthesize libraries of NPs with distinct properties is described. The procedure uses a microfluidic platform that rapidly mixes reagents and provides homogeneous reaction environments, resulting in the reproducible, single-step synthesis of NPs with well-defined properties and narrow size distributions. The microfluidic system is composed of a mixing unit and a NP assembly unit. The mixing unit consists of a multi-inlet, 2-layer mixer where different precursors such as polymers of different MW and charge, ligand- and drug-conjugated polymers, free drugs, and solvents are mixed at different ratios into a homogenous solution. In the assembly unit, the precursor solution is quickly mixed with an anti-solvent (i.e. water) using 3D hydrodynamic flow focusing where NPs self-assemble after complete mixing. With the microfluidic platform, a library of 100 NPs with different sizes (15-200nm), charge (-30 to +30mV), surface chemistry (i.e. PEG coverage), surface ligand density (0-2.510⁵ ligands/[mu]m²), and drug loading (0-5 w/w%) was producedd in a high-throughput manner by simply varying the flow ratios of precursors entering the system. This library was implemented for (i) screening for formulations (in vitro and in vivo) with optimal clinical properties for cancer treatment and (ii) deepening the understanding of how NP properties affect their biological behavior. The platform developed in this work would likely lead to better understanding of the design parameters for polymeric NPs and their smoother transition to the clinic.by Pedro M. Valencia.Ph.D
Production of an Improved Vector for Synthesis and Purification of Eukaryotic Transcription Factors (GAL4-VP16, GAL4-AD and GAL4-D)
The main goal in conducting this series of experiments is to accomplish the construction of an expression vector that contains the coding regions for the GAL4 series transcription factors. This expression vector should possess special characteristics including a histidine tag that helps to easily locate the vector. The other main characteristic is a T7 promoter that allows for a high induction level upon addition of IPTG. The original pET21d expression vector was used in these experiments because it possesses these two intrinsic features. A sub-cloning process of the coding regions of the GAL4 series transcription factors (GAL4-AD, GAL4-D and GAL4-VP16) into the original pET21d expression vector resulted in the pET2Id-GAL4 expression vector. The coding regions for the GAL4-AD and GAL4-D transcription factors were extracted from a pGEX-cs vector by Polymerase Chain Reaction (PCR) amplification with specially designed primers. The GAL4-VP16 transcription factor was extracted from the pJL2 plasmid. In the case of the GAL4-VP16 transcription factor, the sequence was not initially available and experimental sequencing of the transcription factor was necessary to acquire enough information about the sequence to design the primers for the PCR amplification
Evidencias sobre la eficacia de los corredores ecológicos: ¿Solucionan la problemática de fragmentación de hábitats?
Se realiza una revisión del estado de la cuestión con respecto al bagaje científico existente sobre la eficacia de los corredores ecológicos como elementos dirigidos a la conservación de especies en paisajes fragmentados. Previamente se enumeran los efectos potenciales positivos y negativos que pudieran tener los corredores sobre la vida silvestre y se describen las principales dificultades metodológicas que presentan los estudios que tienen como objetivo testar dicha eficacia. Se evidencia la existencia de un nivel probatorio creciente sobre los efectos positivos de corredores ecológicos de características adecuadas en materia de conservación, si bien se espera que aumente significativamente el bagaje científico al respecto en los próximos años. El principio de precaución en materia de conectividad ecológica se torna fundamental dentro de la planificación territorial y sectorial, con el objeto de prevenir la pérdida de funcionalidad de los corredores ecológicos remanentes en el territorio.A review of scientific knowledge about the effectiveness of ecological corridors as elements aimed at the conservation of species in fragmented landscapes is conducted. Before, the potential positive and negative effects that corridors might have on wildlife are listed and the main methodological difficulties that show the studies that aim to test that effectiveness are described. It is clear that there is a growing level of evidence about the positive effects of ecological corridors of appropriate characteristics in terms of conservation, although it is expected that the scientific knowledge in this regard increase significantly in the coming years. The precautionary principle in the field of ecological connectivity becomes crucial in landscape planning, in order to prevent the loss of function of ecological corridors remaining in the territory.On réalise une révision de l’état de la question à l’égard du bagage scientifique existant sur l’efficacité des corridors écologiques, comme des éléments dirigés à la conservation d’espèces dans des paisajes fragmentés. Au préalable on énumère les effets potentiels positifs et négatives que peuvent avoir les corridors sur la vie sauvage et on décrit les difficultés principales méthodologiques que présentent les études qui ont pour but tèster la dite efficacité. Bien que les effets positifs des corridors écologiques adecuats sont évidents, on s’attend que le bagage scientifique à ce sujet augmente significativement dans les prochaines années. Le principe de précaution en matière de connectivité écologique deviene fondamental dans la planification territoriale et séctorielle, afin de prévenir la perte de fonctionnalité des corridors écologiques rémanents dans le territoire
- …