The Risk-Taking Channel and Monetary Transmission Mechanism in Colombia

The recent financial crisis has brought to the forefront the need of a better understanding of the transmission mechanisms of monetary policy. The main step forward in this direction has drawn on work aimed at stressing the role of the financial sector in this transmission. Particular emphasis has been place on how policy actions impact risk perceptions and attitudes of banks and other financial institutions, leading to shifts in the supply of credit. Along these lines, and based on evidence from Colombia, the present paper finds a significant link between low interest rates and banks’ risk taking based on evidence from Colombia. Lower interest rates raise the probability of default on new loans but reduce that on outstanding loans. Furthermore, this channel of policy transmission depends on some bank, loan and borrower characteristics, as well on macroeconomic conditions such as the rate of growth of the economy.Monetary policy, lending standards, risk taking, duration analysis, accelerated failure time models. Classification JEL: E44, G21, L14

Using Machine Learning for Handover Optimization in Vehicular Fog Computing

Smart mobility management would be an important prerequisite for future fog computing systems. In this research, we propose a learning-based handover optimization for the Internet of Vehicles that would assist the smooth transition of device connections and offloaded tasks between fog nodes. To accomplish this, we make use of machine learning algorithms to learn from vehicle interactions with fog nodes. Our approach uses a three-layer feed-forward neural network to predict the correct fog node at a given location and time with 99.2 % accuracy on a test set. We also implement a dual stacked recurrent neural network (RNN) with long short-term memory (LSTM) cells capable of learning the latency, or cost, associated with these service requests. We create a simulation in JAMScript using a dataset of real-world vehicle movements to create a dataset to train these networks. We further propose the use of this predictive system in a smarter request routing mechanism to minimize the service interruption during handovers between fog nodes and to anticipate areas of low coverage through a series of experiments and test the models' performance on a test set

Quantum fields and "Big Rip" expansion singularities

The effects of quantized conformally invariant massless fields on the evolution of cosmological models containing a ``Big Rip'' future expansion singularity are examined. Quantized scalar, spinor, and vector fields are found to strengthen the accelerating expansion of such models as they approach the expansion singularity.Comment: 7 pages; REVTeX

Ultrastructural immunocytochemistry of a Leydig cell enzime and sperm tail protein using antigen retrieval by microwave irradiation

Presentem aquí un protocol simple i ràpid per a la localització de diversos antígens en mostres biològiques incloses en resines acríliques per electromicroscòpia i immunoprecipitació amb or. S'han utilitzat cèll. ules de Leydig de rates adultes separades per gradients de densitat i espermatozoides humans per estudiar la localització subcell. ular d'antígens específics i analitzar la influència de l'exposició a la irradiació per microones sobre la immunoreactivitat valorada per marcatge d'or immunoprecipitat sobre material fixat per formaldehid i inclòs en LR White. Es varen utilitzar seccions ultrafines muntades sobre suports de níquel i immerses en tampó citrat, exposant-les a la irradiació per microones (a màxima potència: 800 W) durant breus períodes de temps. La microscòpia immunoelectrònica es va fer utilitzant anticossos primaris contra l'enzim esteroidogènic (3-beta-hidroxiesteroid-deshidrogenasa, 3-beta-HSD) del reticle endoplasmàtic llis i una proteïna del citosquelet de l'embolcall fibrós de l'espermatozoide (AKAP4). L'anticòs secundari utilitzat fou una immunoglobulina anticonill conjugada amb or (partícules de 15 nm). Les seccions control es varen incubar en sèrum no immune. Les seccions varen ser breument exposades a tetraòxid d'osmi i a acetat d'uranil o foren analitzades, senzillament, sense cap tipus de tinció. El marcatge es va expressar per densitat de partícules d'or per µm2. El soroll de fons fou negligible. La localització de la 3-beta-HSD fou específica en el reticle endoplasmàtic llis de les cèll. ules de Leydig, mentre que els mitocondris i les gotes lipídiques foren negatives. La proteïna AKAP4, principal component de l'embolcall fibrós de la cua de l'espermatozoide i clàssicament localitzada en les fibres d'aquest embolcall fibrós, i en altres components de la cua de l'espermatozoide, varen ser negatius. Després de l'exposició de les seccions a les microones, la densitat de partícules d'or en el reticle endoplasmàtic llis de les cèll. ules de Leydig i en l'embolcall fibrós dels espermatozoides havia augmentat tres vegades en relació amb els mateixos teixits no exposats a les microones, sense comprometre la localització específica de la immunotinció. Aquest mètode permet un augment significatiu de la sensibilitat i de la densitat del marcatge sense modificar les concentracions d'anticòs, l'especificitat o la tinció no específica o de soroll de fons.We report here a simple and fast protocol for enhanced immunogold electronmicroscopic localization of various antigens in biological materials embedded in acrylic resins. Adult rat Leydig cells separated by density gradients and washed human spermatozoa were used to study the subcellular localization of specific antigens and to test the influence of exposure to microwave irradiation on the immunoreactivity assessed by immunogold labeling on formaldehyde fixed, LR White embedded material. Ultrathin sections mounted on nickel grids and immersed in citrate buffer were exposed for brief periods to microwave irradiation at full power (800 W). Immunoelectron microscopy was achieved using primary antibodies raised against a smooth endoplasmic reticulum steroidogenic enzyme (3β Hidroxysteroid Dehydrogenase, 3β- HSD) and a cytoskeletal protein of the sperm fibrous sheath (AKAP4). The secondary antibody was a gold conjugated (15nm particles) anti-rabbit immunoglobulin. Control sections were incubated in non immune serum. Sections were briefly exposed to osmium tetraoxide and uranyl acetate or were observed without any further staining. Labeling was expressed as gold particle density per µm2. Background labeling was negligible. 3β-HSD specifically localized to the smooth endoplasmic reticulum of Leydig cells, while mitochondria and lipid droplets were negative. AKAP4, the main protein component of the fibrous sheath of the sperm tail typically localized to the fibers of the fibrous sheath, while other components of the sperm tail were negative. After on section exposure to microwaves, gold density over the Smooth Endoplasmic Reticulum of Leydig cells and the fibrous sheath of spermatozoa increased by three fold over the same tissues not pretreated by microwaves without compromising the specific localization of the immunolabeling. This method allows for a significant increase of sensitivity and labeling density without modifying antibody concentrations, specificity or background staining

Journey of Research Practice

Welcome to the inaugural issue of the Journal of Research Practice (JRP). This journal has resulted from a widely shared interest that researchers in different disciplines and professional fields should communicate with each other freely and remain open to learn from each other’s individual journey of research.The title of this journal may look surprising to some readers. There may even be a legitimate doubt as to whether the journal would take-off at all, the title being so broad and unspecific. On the contrary, to be more optimistic, the journal could meet a long-felt need, i.e., that of bringing researchers, and various forms of organised inquiry, into fruitful connections with each other, without the restrictions imposed by formal disciplinary boundaries.Research and researchers have been the focus of many discussions in the past. These discussions have proliferated following different threads. There is a logical (and philosophical) thread that seeks to explicate the logic of research and the structure of scientific inquiry, seeking out the rules and methods deployed by researchers in arriving at justifiable results. It also delves into the ideology of scientific research. There is a sociological thread that seeks to understand research communities as social entities and knowledge as a product of social interaction among human beings. There is an institutional or political-economic thread that seeks to understand the workings of regional or national research systems--complete with their councils, funding, and power play. Likewise, there are other threads too, such as research as a space of struggle and resistance, research as a practice of freedom and self-transcendence, etc. There is something to be gained by bringing these threads together, in the hands of researchers themselves, no matter what disciplines or fields they might individually pursue

Characteristics of a multicolor dye laser

An experimental investigation on the possibility of obtaining tunable, multiple wavelength output in mixture of dyes pumped by a nitrogen laser has been carried out. A great number of binary dye mixtures have been tested. Simultaneous two wavelength operation is generally possible provided the gain profiles of both dyes are neither strongly overlapped nor too widely separated. Three color emission is feasible in many mixtures, but the possible combinations are limited. A simple scheme for multiple, simultaneous wavelength tuning is presented

Enhancement of photoacoustic detection of inhomogeneities in polymers

We report a series of experiments on laser pulsed photoacoustic excitationin turbid polymer samples addressed to evaluate the sound speed in the samples and the presence of inhomogeneities in the bulk. We describe a system which allows the direct measurement of the speed of the detected waves by engraving the surface of the piece under study with a fiduciary pattern of black lines. We also describe how this pattern helps to enhance the sensitivity for the detection of an inhomogeneity in the bulk. These two facts are useful for studies in soft matter systems including, perhaps, biological samples. We have performed an experimental analysis on Grilon(R) samples in different situations and we show the limitations of the method.Comment: 8 pages, 7 figure