Antioquia

Direct ink writing technique, an extrusion based additive manufacturing process, has been used to fabricate kaolinite clay based-ceramics with several inexpensive ceramic powders: lime, fly ash and talc. All the above materials are commonly used in the traditional ceramics industry, in both small and large industries, and therefore available worldwide. This research shows the simplicity of the process feasible not only for companies but also for individual users. The samples were fabricated with water to clay ratios (W/C) between 0.68 and 0.72. Additives were tested in 3.0, 5.0 and 7.0wt.% with respect to the clay contents, although 3 wt.% of additives worked best. Cylindrical samples were fabricated with 20mm in diameter and 20mm in height in order to test their compressive strength and density. Measurement samples were previously cured for three days at room temperature and then exposed to 1100?C for 1 h. The powdered additives and their corresponding mixtures with clay were chara...

The calcium ion has long been known to play an important role in cell death regulation. Hence, necrotic cell death was early associated with intracellular Ca 2þ overload, leading to mitochondrial permeability transition and functional collapse. Subsequent characterization of the signaling pathways in apoptosis revealed that Ca 2þ /calpain was critically involved in the processing of the mitochondrially localized, Apoptosis Inducing Factor. More recently, the calcium ion has been demonstrated to play important regulatory roles also in other cell death modalities, notably autophagic cell death and anoikis. In this review, we summarize current knowledge about the mechanisms involved in Ca 2þ regulation of these various modes of cell death with a focus on the importance of the mitochondria.

The electrophysiological correlates of the Stroop color-word interference eect were studied in eight healthy subjects using high-density Event-Related Potentials (ERPs). Three response modalities were compared: Overt Verbal, Covert Verbal, and Manual. Both Overt Verbal and Manual versions of the Stroop yielded robust Stroop color-word interference as indexed by longer RT for incongruent than congruent color words. The Incongruent vs Congruent ERP dierence wave presented two eects. A ®rst eect was a medial dorsal negativity between 350±500 ms post-stimulus (peak at 410 ms). This eect had a signi®cantly dierent scalp distribution in the Verbal and Manual Stroop versions, with an anterior±medial focus for overt or covert speech, and a broader medial±dorsal distribution for the manual task. Dipole source analysis suggested two independent generators in anterior cingulate cortex. Later on in time, a prolonged positivity developed between 500±800 ms post-stimulus over left superior temporo-parietal scalp. This eect was present for all the three response modalities. A possible interpretation of these results is that Stroop color-word interference ®rst activates anterior cingulate cortex (350±500 ms post-stimulus), followed by activation of the left temporo-parietal cortex, possibly related to the need of additional processing of word meaning. #

Brain electrical activity associated with inhibitory control was recorded in ten ADHD and ten healthy children using high density event related potentials (ERPs) during the Stop Signal Task (SST). SST is a two-choice reaction time (RT) paradigm, in which subjects are required, on 25% of the trials, to withdraw their response upon presentation of a "Stop Signal". In the healthy children, the ERP evoked by the Stop Signal differed for successful inhibitions (SI) compared to failed inhibitions (FI), with greater amplitude of a positive wave peaking around 320 msec over anterior medial frontal scalp (P3a). Such success-related P3a activity was significantly reduced in amplitude in the ADHD group. In addition, the error related negativity (ERN), a sharp negative wave that is present selectively on error trials in choice RT experiments, peaking 100 ms after motor onset, and distributed over anterior medial frontal scalp, was also markedly reduced in the ADHD group. The scalp distribution of the group differences in P3a and the ERN is consistent with a reduction of activity of sources in dorsal anterior cingulate cortex (dACC), suggesting a global deficit in cognitive control operations subserved by dACC in ADHD.

El 13 de junio de 1954 sin mucha compresión por un individuo que desde su hogar movía una perilla en una caja de madera y veía imágenes de personas en movimientos, se inauguró la televisión (TV) en Colombia. La TV ha tenido una evolución tanto tecnológica con mayores estándares de los aparatos de TV como en la calidad de imagen, sin dejar atrás que el consumo por los usuarios ha aumentado a tal punto que dejo de ser un lujo de pocos a tener el 95% de cada hogar en Colombia al menos un TV.

Camaleón, la piel árida, reseca de tragarse ojos incendiados, escucha silencioso gestos para hacerse de ellos, para fabricar una pantalla, y suplantarlos. Camaleón anda alegre, se ríe y solloza con sus miles de apariencias, engaña y se engaña, camaleón perdió su color original, pero aún no lo sabe esta sobre la cara de todos.

Imaging spectroscopy, also known as hyperspectral imaging, has been transformed in less than thirty years from being a sparse research tool into a commodity product available to a broad user community. Currently, there is a need for standardized data processing techniques able to take into account the special properties of hyperspectral data. In this paper, we provide a seminal view on recent advances in techniques for hyperspectral image processing. Our main focus is on the design of techniques able to deal with the high-dimensional nature of the data, and to integrate the spatial and spectral information. Performance of the discussed techniques is evaluated in different analysis scenarios. To satisfy time-critical constraints in specific applications, we also develop efficient parallel implementations of some of the discussed algorithms. Combined, these parts provide an excellent snapshot of the state-ofthe-art in those areas, and offer a thoughtful perspective on future potentials and emerging challenges in the design of robust hyperspectral imaging algorithms.

Hyperspectral imaging offers the possibility of characterizing materials and objects in the air, land and water on the basis of the unique reflectance patterns that result from the interaction of solar energy with the molecular structure of the material. In this paper, we provide a seminal view on recent advances in techniques for hyperspectral data processing. Our main focus is on the development of approaches able to naturally integrate the spatial and spectral information available from the data. Special attention is paid to techniques that circumvent the curse of dimensionality introduced by high-dimensional data spaces. Experimental results, focused in this work on a specific case-study of urban data analysis, demonstrate the success of the considered techniques. This paper represents a first step towards the development of a quantitative and comparative assessment of advances in hyperspectral data processing techniques. 0-7803-9510-7/06/$20.00

The FLuorescence EXplorer (FLEX) mission proposes to launch a satellite for the global monitoring of steady-state chlorophyll fluorescence in terrestrial vegetation. Fluorescence is a sensitive probe of photosynthetic function in both healthy and physiologically perturbed vegetation, and a powerful non-invasive tool to track the status, resilience, and recovery of photochemical processes and moreover provides important information on overall photosynthetic performance with implications for related carbon sequestration. The early responsiveness of fluorescence to atmospheric, soil and plant water balance, as well as to atmospheric chemistry and human intervention in land usage makes it an obvious biological indicator in improving our understanding of Earth system dynamics. The amenability of fluorescence to remote, even space-based observation qualifies it to join the emerging suite of space-based technologies for Earth observation. FLEX would encompass a three-instrument array for measurement of the interrelated features of fluorescence, hyperspectral reflectance, and canopy temperature. FLEX would involve a space and ground-truthing program of 3-years duration and would provide data formats for research and applied science.

Two research stories provide a means of looking backward at our discipline over the twentieth century and of thinking about moving forward in the twenty-first. These stories recount individuals' quest for control when their moral status is threatened. Both research stories and sociological stories render reality, subscribe to rulesfor such renderings, contain an inner logic, and make moral claims for credibility. When looking backward at the discipline, sociologists need to build on the classical theorists, not dismiss them. At the millennium sociological theory and methods are contested; and challenges to foundational assumptions that gained momentum in the late 1960s have recently been raised anew. Movingforward in the twenty-first century means recommitting ourselves to empirical inquiry and basing our moral claims on it. I call for acknowledging the diversity of sociological approaches, agreeing on strong standards for each approach, and recognizing and examining our disciplinary moral claims. SOCIOLOGICAL PERSPECTIVES Volume 43, Number 4,2000 patients (which is what some residents, and perhaps staff, thought I was-my youth, notebook, and claims to be doing research probably convinced them). Finding a treatable disability to legitimate patients' admission to the center seldom posed problems. Their bodies had worn out from hard lives, troubled times, and grueling jobs.