Andres Uribe - Academia.edu (original) (raw)

Papers by Andres Uribe

2019 IEEE Latin American Conference on Computational Intelligence (LA-CCI)

This article presents the development of a mobile application that exploits a Convolutional Neura... more This article presents the development of a mobile application that exploits a Convolutional Neural Network (CNN) to recognize a set of fruits and vegetables by processing snapshots taken by the built-in camera of the device. We built an acquisition system to gather pictures of different kinds of fruits and vegetables to train a neural network model. Instead of defining a new topology and training it from scratch, we took advantage of transfer learning and fine-tuned several MobileNet models to classify our images in their corresponding classes on a smartphone. Once the fruit or vegetable is identified, our mobile application provides valuable nutritional information about it.

SSRN Electronic Journal, 2018

Television is an overlooked tool of state building. We estimate the impact of televising criminal... more Television is an overlooked tool of state building. We estimate the impact of televising criminal proceedings on public use of government courts to resolve disputes. We draw on survey data from Afghanistan, where the government used television as a mechanism for enhancing the legitimacy of formal legal institutions during an ongoing conflict. We find consistent evidence of court 'uptake' among survey respondents who trust television following the nation's first televised criminal trial. We find no evidence that public confidence in other government functions (e.g. economy, development, corruption) improved during this period. Our findings suggest that television may provide a means of building state legitimacy during war. Submission Type: Short Article * We thank Luke Condra and Kenneth Holland for helpful comments. The authors are grateful to the North Atlantic Treaty Organization's Communications and Information Agency for granting access to the survey materials used in this study. A particular debt of gratitude is owed to Philip T. Eles, senior scientist at the Agency, for providing continued support for and feedback on this project. All errors remain with the authors.

Liquefaction-induced damage has been reported in numerous seismic events around the world: Alaska... more Liquefaction-induced damage has been reported in numerous seismic events around the world: Alaska 1964, Japan 1995, Turkey 1999, Taiwan 1999, Iran 2004 and China 2008. Historically, Southern California has been seismically active for a radius of 300 km around the Port of Long Beach. At least 189 earthquakes were registered from year 1800 until present. The Port of Long Beach is located within a few miles of this fault line, and is also near the Newport-Inglewood and the Palos Verdes faults. The port has experienced significant expansion projects in the past decades which have been completed by placing hydraulic fill behind rock retention dikes. These man-made loose deposits have shown to be susceptible to liquefaction.

These Ecole polytechnique federale de Lausanne EPFL, n° 2052 (1999)Faculte informatique et commun... more These Ecole polytechnique federale de Lausanne EPFL, n° 2052 (1999)Faculte informatique et communicationsLaboratoire de systemes logiquesJury: Igor Aleksander, Joan Cabestany, Wulfram Gerstner, Pierre Marchal, Jean-Daniel Nicoud, Eduardo Sanchez Public defense: 1999-10-22 Reference doi:10.5075/epfl-thesis-2052Print copy in library catalog Record created on 2005-03-16, modified on 2016-08-08

Presidential Studies Quarterly, 2020

Scholars and the general public have been struck by the norm‐shattering rhetoric of President Don... more Scholars and the general public have been struck by the norm‐shattering rhetoric of President Donald J. Trump. His “rhetorical signature” is heavy with Manichean good‐versus‐evil messages, vilification of his opponents, and disdain for institutions and for evidence. But many politicians vilify their opponents and style themselves as uniquely able to solve their society's problems. In fact, Trump's Manichean discourse is typical of populist leaders, in the United States and around the world. Using text‐as‐data analysis of campaign rhetoric, we study the content and mood of presidential campaign speeches by a range of U.S. politicians, which allows a broader perspective not only on the uniqueness of Trump's rhetoric, but also its continuities with the rhetoric of others. This analysis allows us to define Trump as a right‐wing populist. Right‐wing populists, like left‐leaning ones, are anti‐elitist and Manichean in words and outlook. However, the two versions of populism di...

Journal of Functional Foods, 2018

To test the hypothesis that epicatechin doses of 1.6, 3.2 and 4.8 mg per kg of body weight in a n... more To test the hypothesis that epicatechin doses of 1.6, 3.2 and 4.8 mg per kg of body weight in a nonalkalized cocoa beverage cause significant acute decreases in human appetite that increase with increasing dose. Methods: We conducted a four-way randomized, crossover, placebo-controlled double-blinded human trial with 28 healthy, non-obese, young-adult male participants. Our primary measure of appetite was ad libitum pizza intake 150 min after beverage ingestion. We used linear mixed models analyses. Results: Compared to our placebo, the beverages containing 1.6, 3.2 and 4.8 mg per kg of body weight caused mean decreases in pizza intake of 984.3 kJ (18.1%, p = .002), 588.0 kJ (10.8%, p = .06) and 623.2 kJ (11.4%, p = .049), respectively. There were no reported adverse side effects related to the ingested beverages. Conclusions: In our randomized trial two doses of epicatechin larger than1.6 mg/kg did not cause larger acute decreases in pizza intake.

HortScience, 2010

Water use efficiency (WUE) and response of grape vines (Vitis vinifera L. cvs. ‘Cabernet Sauvigno... more Water use efficiency (WUE) and response of grape vines (Vitis vinifera L. cvs. ‘Cabernet Sauvignon’, ‘Merlot’, and ‘Viognier’) to a particle film treatment (PFT) under varying levels of applied water were evaluated in Victoria, Australia, and southwestern Idaho. Vines that received the least amount of water had the warmest canopy or leaf surface temperature and the lowest (more negative) leaf water potential, stomatal conductance (gS), transpiration (E), and photosynthesis (A). Vines with plus-PFT had cooler leaf and canopy temperature than non-PFT vines; however, temperature difference resulting from irrigation was greater than that resulting from PFT. In well-watered vines, particle film application increased leaf water potential and lowered gS. Point-in-time measurements of WUE (A/E) and gS did not consistently correspond with seasonal estimates of WUE based on carbon isotope discrimination of leaf or shoot tissue. The response of vines with particle film to undergo stomatal clos...

Agronomia Colombiana, Apr 1, 2013

The need for more efficient nutrient use in adverse conditions, such as droughts, facilitated the... more The need for more efficient nutrient use in adverse conditions, such as droughts, facilitated the development of new alternatives for fertilizer application, such as direct insertion into the vascular system of the pseudostem of harvested banana plants (Musa AAA Simmonds), considering the plant interconnection between the mother plant and the sucker in succession. The objective of this study was to evaluate the effect of fertilizer insertion into the pseudostem of banana plants compared to the conventional soil fertilization system. The study was conducted at two locations (north and center of Urabá region), setting different rates of fertilizer treatments (75, 100 and 125% of the commercial rate) inserted at different heights (0.6 m and 0.9 m) with a soil application of fertilizers as a control treatment. Biometric (height, pseudostem diameter, number of leaves), physiological (specific leaf area and specific leaf weight), and production variables were evaluated in the plants. According to the results, it was evident that the 0.9 m insertion height of the fertilizer was better than 0.6 m and the soil application. Although no significant differences were found between doses of fertilizer, we observed a trend of better performance for plants in treatments of 75% and 100% fertilizer dose inserted at 0.9 m. La necesidad de hacer más eficiente el uso nutrientes en condiciones adversas como la sequía ha permitido el desarrollo de nuevas alternativas de aplicación de fertilizantes como la inserción directa al sistema vascular del seudotallo o "troncón" de la planta cosechada del banano (Musa AAA Simmonds), teniendo en cuenta la intercomunicación que existe entre la planta madre y el hijo en sucesión. El objetivo del ensayo fue evaluar la eficiencia de inserción del fertilizante al troncón comparado con la fertilización edáfica convencional. El ensayo se realizó en dos localidades (zona norte y centro) de Urabá (Colombia), con cuatro dosis de fertilizante (75, 100 y 125% de la dosis comercial y fertilización edáfica) insertadas en el seudotallo a 0,9 y 0,6 m. Se tomaron variables de crecimiento (altura, diámetro del seudotallo, número de hojas), fisiológicas (área foliar específica, peso foliar especifico) y producción. La inserción del fertilizante a 0,9 m fue más efectiva que a 0,6 m y que la fertilización al suelo. Aunque no se evidenciaron diferencias significativas entre las dosis de fertilizante, se pudo observar una tendencia de mejor comportamiento de las plantas en los tratamientos de 75 y 100% de la dosis comercial insertados a 0,9 m.

Neuroendocrinology, 2015

Background: There is growing evidence that maternal obesity and prenatal exposure to a high-fat d... more Background: There is growing evidence that maternal obesity and prenatal exposure to a high-fat diet program fetal development to regulate the physiology and behavior of the offspring in adulthood. Yet the extent to which the maternal dietary environment contributes to adult disease vulnerability remains unclear. In the current study we tested whether prenatal exposure to maternal obesity increases the offspring's vulnerability to stress-related psychiatric disorders. Methods: We used a mouse model of maternal diet-induced obesity to investigate whether maternal obesity affects the response to adult chronic stress exposure in young adult (3-month-old) and aged adult (12-month-old) offspring. Results: Long-lasting, delayed impairments to anxiety-like behaviors and stress coping strategies resulted on account of prenatal exposure to maternal obesity. Although maternal obesity did not change the offspring's behavioral response to chronic stress per se, we demonstrate that the b...

European Journal of Gastroenterology and Hepatology, 2001

Objectives Cytokines stimulate lymphocyte cell proliferation and affect cell division in several ... more Objectives Cytokines stimulate lymphocyte cell proliferation and affect cell division in several other cell types. Helicobacter pylori-induced gastritis and coeliac disease are characterized by an increased cell proliferation in association with an increased production of pro-in¯ammatory cytokines, which could contribute to these cell kinetic changes. Our aim is to examine in vitro whether cytokines usually present in the gastrointestinal mucosa affect DNA synthesis and apoptosis in a rat and a human small-intestinal cell line. Methods IEC-6 and FHs-74 cells were incubated for 24 h with 10 À13 ±10 À9 M of tumour necrosis factor alpha (TNFá), interleukin-1â (IL-1â), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), transforming growth factor-beta (TGF-â) and interferon gamma (IFN-ã). IEC-6 cells were also incubated with 10 À13 ±10 À9 M of interleukin-1á (IL-1á) and 10 À8 M of interleukin-1 receptor antagonist (IL-1ra). The cells were labelled with 3 H-methyl thymidine for the ®nal 4 hours, and then processed for autoradiography. DNA synthesis was evaluated by the labelling index (LI%). Apoptosis was evaluated in IEC-6 cells by changes in membrane lipid asymmetry using annexin-V binding to externalized phosphatidylserine (¯ow cytometry) and by estimating the caspase activity. Results TNF-á, IL-1â, IL-8 and IFN-ã signi®cantly and markedly increased the LI, even at low concentrations (P < 0.0001), in both IEC-6 and FHs-74 cells, as did IL-1á in IEC-6 cells. TGF-â signi®cantly reduced the LI in both cell lines (P < 0.0001), whereas IL-2, IL-6 and IL-1ra did not affect DNA synthesis signi®cantly. None of IL-1â, IL-8, TNFá or IFN-ã affected apoptosis in IEC-6 cells. Conclusion TNF-á, IL-1á, IL-1â, IL-8 and IFN-ã stimulated DNA synthesis in a human and a rat small-intestinal cell line. The cytokines exert their mitogenic action directly on the intestinal cells via speci®c receptors. Our ®ndings indicate that pro-in¯ammatory cytokines may participate in the regulation of the gastrointestinal epithelial cell proliferation in health and disease.

Socio-Economic Planning Sciences, 2012

The Institute of Medicine (IOM) has pointed out that the existing pandemic mitigation models lack... more The Institute of Medicine (IOM) has pointed out that the existing pandemic mitigation models lack the dynamic decision support capability. In this paper, we present a simulation optimization model to generate dynamic strategies for distribution of limited mitigation resources, such as vaccines and antivirals, over a network of regional outbreaks. The model has the capability to redistribute the resources remaining from previous allocations in response to changes in the pandemic progress. The model strives to minimize the impact of ongoing outbreaks and the expected impact of potential outbreaks, considering measures of morbidity, mortality, and social distancing, translated into the societal and economic costs of lost productivity and medical services. The model is implemented on a simulated H5N1 outbreak involving four counties in the state of Florida, U.S. with over four million inhabitants. The performance of our strategy is compared to that of a myopic distribution strategy. Sensitivity analysis is performed to assess the impact of variability of some critical factors on policy performance. The methodology is intended to support public health policy on effective distribution of limited mitigation resources.

Scandinavian Journal of Gastroenterology, 1992

The aim of the present investigation was to study the effect of a long-term and a short-term trea... more The aim of the present investigation was to study the effect of a long-term and a short-term treatment regimen with 15-R-15-methyl prostaglandin E2 and natural prostaglandin E2 (PGE2) on the endocrine cell populations of the rat pancreas. Graded oral doses of the analogue (5 and 50 micrograms/kg) and PGE2 (5000 micrograms/kg) were given twice daily for 4 weeks. The pancreas was carefully excised and weighed. Sections from randomly taken pancreatic biopsy specimens were processed for immunohistochemistry or hematoxylin and eosin staining before quantitative estimations were made, using stereologic methods. The total pancreatic volumes of insulin-, glucagon-, polypeptide P-, somatostatin-, and chromogranin A-immunoreactive cells were not affected by E2 prostaglandins. Neither the total volume of the islets of Langerhans nor that of the pancreatic cell nuclei was affected. The size of pancreatic cell nuclei was the same in the groups. The plasma levels of the antitrophic peptide somatostatin were significantly increased in rats treated with doses of both the analogue and PGE2 (p less than 0.05). In an additional short-term study rats were given oral placebo or 5000 micrograms/kg PGE2 twice daily for 5 days. The total endocrine pancreatic volume was not affected by PGE2. As in the long-term study, natural PGE2 did not affect the total pancreas volume or the total volume of pancreatic cell nuclei. These findings indicate that E2 prostaglandins produce no changes in the exocrine or endocrine pancreas in a dose range known to induce hyperplasia in the gastrointestinal epithelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Scandinavian Journal of Gastroenterology, 1987

Proliferative and functional epithelial cells were isolated from jejunal specimens of the rat by ... more Proliferative and functional epithelial cells were isolated from jejunal specimens of the rat by means of vibrational treatment combined with differential air insufflation. This method gave a good separation between superficial cells of the villi and the crypt cells, as evaluated by flow cytometry, morphology, cytology, and incorporation of radioactive thymidine into DNA. Groups of Sprague-Dawley rats (260 g) were treated twice daily for 11 days with oral placebo, 15(R)15-methyl-prostaglandin E2 in the range of 0.125-2 mg X kg-1, or 5 mg X kg-1 natural PGE2. Isolated crypt cells and superficial cells of the jejunal villi were then analysed by flow cytometry. Morphometric measurements were performed on sections of some jejunal specimens not submitted to vibrational treatment. The cell cycle distribution of crypt cells was unaffected by treatment with the prostaglandin analogue despite the presence of trophic changes. The proportion of crypt cells in G2/M phase was slightly but significantly reduced in rats given natural PGE2 compared with controls. The cell cycle distribution of villus cells was not affected by prostaglandin treatment. Trophic changes in the absence of increased DNA synthesis (S phase) or increased mitotic activity suggests that the hyperplasia observed after prostaglandin treatment is due to a reduced cell loss and/or slower migration time of epithelial cells.

Scandinavian Journal of Gastroenterology, 1997

Previous studies suggest that E2 prostaglandins and the microflora may participate in the regulat... more Previous studies suggest that E2 prostaglandins and the microflora may participate in the regulation of endocrine cells and of gastrointestinal cell kinetics. Our aim is to examine the actions of endogenous prostaglandins and of the microflora on gastrointestinal cell proliferation and tissue levels of neuroendocrine peptides. Germfree and ex-germfree rats were treated with subcutaneous placebo or 1.5 mg/kg indomethacin for 3 days. All rats were labeled with 3H-methyl-thymidine, and biopsy specimens from different parts of the gastrointestinal tract were processed for autoradiography. DNA synthesis was estimated by the labeling index, except in the oxyntic mucosa, where the total number of labeled cells present in 7.5 mm mucosa was used. The concentration of neuroendocrine peptides was determined by radioimmunoassay. In the germfree rat, indomethacin reduced DNA synthesis in the fundus, duodenum, and proximal jejunum (P < 0.05) and the number of villous cells throughout the small intestine (P < 0.05). Exposure to microflora increased DNA synthesis in the proximal and distal jejunum, ileum, and colon (P < 0.05 versus germfree controls) and the number of crypt cells in the distal small intestine and colon (P < 0.05) and reduced the number of villous cells in the small intestine (P < 0.05) but did not affect tissue concentrations of neuroendocrine peptides. Indomethacin increased the concentration of somatostatin in the stomach, duodenum, and colon of germfree rats (P < 0.001), the concentration of calcitonin gene-related peptide (CGRP) and enteroglucagon in the proximal and distal jejunum and ileum (P < 0.001), and the concentration of glucagon in the colon (P < 0.05). The concentrations of somatostatin, CGRP, and glucagon were lower in indomethacin-treated ex-germfree rats than in indomethacin-treated germfree rats (P < 0.01). Indomethacin selectively reduced DNA synthesis in the upper gastrointestinal tract of germfree rats, indicating a basal stimulatory role for endogenous prostaglandins on cell proliferation. Endogenous prostaglandins modulate synthesis or release of gastrointestinal neuroendocrine peptides. Somatostatin may mediate indomethacin-induced reduction of DNA synthesis. The microflora stimulates cell proliferation and influences tissue levels of neuroendocrine peptides in a manner opposite to that of indomethacin.

Preparative Biochemistry and Biotechnology, 1999

Bacterial constituents and products of the bacterial metabolism pass from the gut lumen to the po... more Bacterial constituents and products of the bacterial metabolism pass from the gut lumen to the portal vein and may influence the homeostasis of the liver. Our aim is to examine whether DNA synthesis of human hepatocyte cell lines is affected by constituents of Escherichia coli species as well as by intracolonic products of bacterial fermentation that reach the liver via the portal vein. Supernatant solutions and bacterial cell fractions (containing either whole dead bacteria, cell walls, cytosol or non-soluble intracellular components) of E. coli K12 and of E. coli species from rat fecal flora were separated by multi-step centrifugation, French press, and microfiltration. The supernatant solution and the cell fractions were incubated with a human hepatoma cell line (Hep-G2) and with a cell line derived from non-malignant human liver cells (Chang cells) for 24 h. The cells were labeled with tritiated thymidine before processing to autoradiography. DNA synthesis was estimated by the labeling index (LI%). DNA synthesis was also estimated following incubation of Hep-G2 cells with short chain fatty acids (acetic, propionic, butyric and succinic acid), acetaldehyde, and ammonium chloride. Epidermal growth factor and a water extract of Helicobacter pylori were used as references. The fractions of E. coli from rat fecal flora containing cytosol and non-soluble intracellular components significantly increased the labeling index in both Hep-G2 and Chang cells (p < 0.05). In addition, the supernatant solution significantly increased the LI in Chang cells (p < 0.05). Epidermal growth factor increased the LI of Hep-G2 cells dose-dependently (p < 0.05). Butyric acid reduced DNA synthesis at 10(-4) M (p < 0.05). The highest doses of acetaldehyde were cytotoxic and reduced the LI. Escherichia coli species contain mitogenic factors to human hepatocytes. The mitogen(s) are present in the supernatant solution, in the cytosol and in non-soluble intracellular components. Butyrate, which is a product of bacterial fermentation of colonic substrates inhibit DNA synthesis in the hepatocyte cell lines. Our findings suggest that soluble mitogen(s) that diffuse from the microorganism to the outer environment, intracellular bacterial constituents, and products of the bacterial metabolism that reach the liver via the portal vein may influence the cell kinetic steady-state of hepatic cells.

Journal of Endocrinology, 2014

While it is known that stress promotes obesity, the effects of stress within an obesogenic contex... more While it is known that stress promotes obesity, the effects of stress within an obesogenic context are not so clear and molecular targets at the interface remain elusive. The FK506-binding protein 51 (FKBP51, gene:Fkbp5) has been identified as a target gene implicated in the development of stress-related psychiatric disorders and is a possible candidate for involvement in stress and metabolic regulation. The aims of the current study are to investigate the interaction between chronic stress and an obesogenic context and to additionally examine whether FKBP51 is involved in this interaction. For this purpose, male C57BL/6 mice were exposed to a high-fat diet for 8 weeks before being challenged with chronic social defeat stress. Herein, we demonstrate that chronic stress induces hypophagia and weight loss, ultimately improving features arising from an obesogenic context, including glucose tolerance and levels of insulin and leptin. We show thatFkbp5expression is responsive to diet and...

Logo Universidad La Sabana. ...

Helicobacter, 1999

Background.During the conversion from the bacillary into the coccoid form, Helicobacter pylori or... more Background.During the conversion from the bacillary into the coccoid form, Helicobacter pylori organisms are known to change extensively. The aim of this study was to determine some of the changes that occur regarding morphology, intracellular composition and surface properties during the aging of bacteria in vitro.Materials and Methods. H. pylori from agar plate cultures of different ages was used in this study. The intracellular composition of the two morphological forms of the bacteria was tested by density centrifugation, DNA extraction and quantitative OD, mRNA and ATP measurements. Immunoblotting was used to observe changes in secreted/superficial protein patterns, and hydrophobicity measurements were used to observe changes in surface properties.Results.All bacillary H. pylori organisms changed morphology gradually over 10 days of culture. Rods had a higher density than cocci; bacteria stored in PBS had the highest density and bacteria stored in water had the lowest. The quan...