Training needs of the agricultural assistants (Practicos agricolas) in the Colombian Agricultural Institute (ICA).

Maestría en CienciasMaestrí

Smile detection in the wild based on transfer learning

Smile detection from unconstrained facial images is a specialized and challenging problem. As one of the most informative expressions, smiles convey basic underlying emotions, such as happiness and satisfaction, which lead to multiple applications, e.g., human behavior analysis and interactive controlling. Compared to the size of databases for face recognition, far less labeled data is available for training smile detection systems. To leverage the large amount of labeled data from face recognition datasets and to alleviate overfitting on smile detection, an efficient transfer learning-based smile detection approach is proposed in this paper. Unlike previous works which use either hand-engineered features or train deep convolutional networks from scratch, a well-trained deep face recognition model is explored and fine-tuned for smile detection in the wild. Three different models are built as a result of fine-tuning the face recognition model with different inputs, including aligned, unaligned and grayscale images generated from the GENKI-4K dataset. Experiments show that the proposed approach achieves improved state-of-the-art performance. Robustness of the model to noise and blur artifacts is also evaluated in this paper

Degradación fotocatalítica de un derivado del 4,4'-bis(1,3,5- triazinilamino)-estilbeno-2,2'-disulfonato en solución acuosa por el proceso foto-fenton (uv/fe3+/h2o2 )

La degradación fotocatalítica del blanqueador óptico derivado del 4,4'-bis(1,3,5- triazinilamino)-estilbeno-2,2'-disulfonato fue realizada por el proceso de oxidación avanzada UV/Fe+3/H2O2 (foto-Fenton). Se encontraron las condiciones óptimas de pH, concentraciones de Fe+3, H2O2. Durante el fototratamiento, fueron hechos ensayos para obtener información concerniente a la variación de: a) las absorbancias relativas y b) Demanda química de oxígeno (DQO) de la solución del blanqueador óptico tratada. Con este sistema de fotodegradación, el 72% de la concentración inicial del compuesto fue removido y se obtuvo unamineralización del 65% de la muestra total

Degradación fotocatalítica de un derivado del 4,4'-bis(1,3,5- triazinilamino)-estilbeno-2,2'-disulfonato en solución acuosa por el proceso foto-fenton (uv/fe3+/h2o2 )

La degradación fotocatalítica del blanqueador óptico derivado del 4,4'-bis(1,3,5- triazinilamino)-estilbeno-2,2'-disulfonato fue realizada por el proceso de oxidación avanzada UV/Fe+3/H2O2 (foto-Fenton). Se encontraron las condiciones óptimas de pH, concentraciones de Fe+3, H2O2. Durante el fototratamiento, fueron hechos ensayos para obtener información concerniente a la variación de: a) las absorbancias relativas y b) Demanda química de oxígeno (DQO) de la solución del blanqueador óptico tratada. Con este sistema de fotodegradación, el 72% de la concentración inicial del compuesto fue removido y se obtuvo unamineralización del 65% de la muestra total

Cáncer de tiroides en nódulo hipercaptante por gammagrafía. Serie de casos.

La presencia de nódulos tiroideos es una condición clínica de alta prevalencia en la población general.Cuando gammagráficamente son hipercaptantes a menudo se considera como una condición benigna;sin embargo, a pesar de presentarse esta condición, cuando la clínica es sugestiva de malignidad, es recomendado la realización de un estudio histológico. En este artículo se presentan tres casos en los que la clínica nos hizo sospechar de malignidad y se confirmó con estudios histológicos posteriores

Water Use, Leaf Cooling and Carbon Assimilation Efficiency of Heat Resistant Common Beans Evaluated in Western Amazonia

In our study, we analyzed 30years of climatological data revealing the bean production risks for Western Amazonia. Climatological profiling showed high daytime and nighttime temperatures combined with high relative humidity and low vapor pressure deficit. Our understanding of the target environment allows us to select trait combinations for reaching higher yields in Amazonian acid soils. Our research was conducted using 64 bean lines with different genetic backgrounds. In high temperatures, we identified three water use efficiency typologies in beans based on detailed data analysis on gasometric exchange. Profligate water spenders and not water conservative accessions showed leaf cooling, and effective photosynthate partitioning to seeds, and these attributes were found to be related to higher photosynthetic efficiency. Thus, water spenders and not savers were recognized as heat resistant in acid soil conditions in Western Amazonia. Genotypes such as BFS 10, SEN 52, SER 323, different SEFs (SEF 73, SEF 10, SEF 40, SEF 70), SCR 56, SMR 173, and SMN 99 presented less negative effects of heat stress on yield. These genotypes could be suitable as parental lines for improving dry seed production. The improved knowledge on water-use efficiency typologies can be used for bean crop improvement efforts as well as further studies aimed at a better understanding of the intrinsic mechanisms of heat resistance in legumes

Reorganizing the Intrinsic Functional Architecture of the Human Primary Motor Cortex during Rest with Non-Invasive Cortical Stimulation

The primary motor cortex (M1) is the main effector structure implicated in the generation of voluntary movements and is directly involved in motor learning. The intrinsic horizontal neuronal connections of M1 exhibit short-term and long-term plasticity, which is a strong substrate for learning-related map reorganization. Transcranial direct current stimulation (tDCS) applied for few minutes over M1 has been shown to induce relatively long-lasting plastic alterations and to modulate motor performance. Here we test the hypothesis that the relatively long-lasting synaptic modification induced by tDCS over M1 results in the alteration of associations among populations of M1 neurons which may be reflected in changes of its functional architecture. fMRI resting-state datasets were acquired immediately before and after 10 minutes of tDCS during rest, with the anode/cathode placed over the left M1. For each functional dataset, grey-matter voxels belonging to Brodmann area 4 (BA4) were labelled and afterwards BA4 voxel-based synchronization matrices were calculated and thresholded to construct undirected graphs. Nodal network parameters which characterize the architecture of functional networks (connectivity degree, clustering coefficient and characteristic path-length) were computed, transformed to volume maps and compared before and after stimulation. At the dorsolateral-BA4 region cathodal tDCS boosted local connectedness, while anodal-tDCS enhanced long distance functional communication within M1. Additionally, the more efficient the functional architecture of M1 was at baseline, the more efficient the tDCS-induced functional modulations were. In summary, we show here that it is possible to non-invasively reorganize the intrinsic functional architecture of M1, and to image such alterations

Neural correlates of evidence accumulation during value-based decisions revealed via simultaneous EEG-fMRI

Current computational accounts posit that, in simple binary choices, humans accumulate evidence in favour of the different alternatives before committing to a decision. Neural correlates of this accumulating activity have been found during perceptual decisions in parietal and prefrontal cortex; however the source of such activity in value-based choices remains unknown. Here we use simultaneous EEG–fMRI and computational modelling to identify EEG signals reflecting an accumulation process and demonstrate that the within- and across-trial variability in these signals explains fMRI responses in posterior-medial frontal cortex. Consistent with its role in integrating the evidence prior to reaching a decision, this region also exhibits task-dependent coupling with the ventromedial prefrontal cortex and the striatum, brain areas known to encode the subjective value of the decision alternatives. These results further endorse the proposition of an evidence accumulation process during value-based decisions in humans and implicate the posterior-medial frontal cortex in this process