Integrando el uso de habilidades espaciales y geométricas para el aprendizaje significativo del concepto de volumen de sólidos con estudiantes de dibujo técnico

El presente reporte plantea la necesidad de estudiar la problemática que gira en torno al aprendizaje del concepto de volumen de cuerpos sólidos desde el análisis del contexto del desarrollo del pensamiento espacial de estudiantes que demuestran habilidades en cursos independientes de la matemática escolar como es el dibujo técnico. Uno de los objetivos es proponer una metodología de trabajo que permita potenciar dichas habilidades en el aprendizaje de algunos conceptos geométricos, en particular el concepto de volumen, a través de un proyecto de aula transversal entre las áreas de dibujo y matemáticas con estudiantes de secundaria (13-14 años) del Instituto Técnico Industrial Francisco de Paula Santander ubicado en la ciudad de Puente Nacional (departamento de Santander en Colombia)

Competitividad y medio ambiente: la construcción de patrones exportadores sustentables en América Latina

In this study we discuss the need to develop sustainable export patterns in Latin America that fulfill two criteria: reduce the importance of activities that impose the greatest environmental impacts and increase the relevance of activities and products with a higher technological content, since these are the most dynamic in international markets, tend to be cleaner, and present positive spillovers to the rest of the economy. We propose a conceptual framework and analyze the export profiles of Argentina, Brazil, Chile and Mexico, where the heterogeneity among Latin American countries is evident. We conclude that the development of sustainable export patterns will require decisive actions in the environmental and technological domains.trade; environment; technological development; Latin America

Nonabelian 2D Gauge Theories for Determinantal Calabi-Yau Varieties

The two-dimensional supersymmetric gauged linear sigma model (GLSM) with abelian gauge groups and matter fields has provided many insights into string theory on Calabi--Yau manifolds of a certain type: complete intersections in toric varieties. In this paper, we consider two GLSM constructions with nonabelian gauge groups and charged matter whose infrared CFTs correspond to string propagation on determinantal Calabi-Yau varieties, furnishing another broad class of Calabi-Yau geometries in addition to complete intersections. We show that these two models -- which we refer to as the PAX and the PAXY model -- are dual descriptions of the same low-energy physics. Using GLSM techniques, we determine the quantum K\"ahler moduli space of these varieties and find no disagreement with existing results in the literature.Comment: v3: 46 pages, 1 figure. Corrected phase structure of general linear determinantal varieties. Typos correcte

Two-Sphere Partition Functions and Gromov-Witten Invariants

Many N=(2,2) two-dimensional nonlinear sigma models with Calabi-Yau target spaces admit ultraviolet descriptions as N=(2,2) gauge theories (gauged linear sigma models). We conjecture that the two-sphere partition function of such ultraviolet gauge theories -- recently computed via localization by Benini et al. and Doroud et al. -- yields the exact K\"ahler potential on the quantum K\"ahler moduli space for Calabi-Yau threefold target spaces. In particular, this allows one to compute the genus zero Gromov-Witten invariants for any such Calabi-Yau threefold without the use of mirror symmetry. More generally, when the infrared superconformal fixed point is used to compactify string theory, this provides a direct method to compute the spacetime K\"ahler potential of certain moduli (e.g., vector multiplet moduli in type IIA), exactly in {\alpha}'. We compute these quantities for the quintic and for R{\o}dland's Pfaffian Calabi-Yau threefold and find agreement with existing results in the literature. We then apply our methods to a codimension four determinantal Calabi-Yau threefold in P^7, recently given a nonabelian gauge theory description by the present authors, for which no mirror Calabi-Yau is currently known. We derive predictions for its Gromov-Witten invariants and verify that our predictions satisfy nontrivial geometric checks.Comment: 25 pages + 2 appendices; v2 corrects a divisor in K\"ahler moduli space and includes a new calculation that confirms a geometric prediction; v3 contains minor update of Gromov-Witten invariant extraction procedur

Aditivos orgánicos para estabilizar construcción de tierra en sitios prehispánicos de México

Published versio

Learning regions of interest from low level maps in virtual microscopy

Virtual microscopy can improve the workflow of modern pathology laboratories, a goal limited by the large size of the virtual slides (VS). Lately, determination of the Regions of Interest has shown to be useful in navigation and compression tasks. This work presents a novel method for establishing RoIs in VS, based on a relevance score calculated from example images selected by pathologist. The process starts by splitting the Virtual Slide (VS) into a grid of blocks, each represented by a set of low level features which aim to capture the very basic visual properties, namely, color, intensity, orientation and texture. The expert selects then two blocks i.e. A typical relevant (irrelevant) instance. Different similarity (disimilarity) maps are then constructed, using these positive (negative) examples. The obtained maps are then integrated by a normalization process that promotes maps with a similarity global maxima that largely exceeds the average local maxima. Each image region is thus entailed with an associated score, established by the number of closest positive (negative) blocks, whereby any block has also an associated score. Evaluation was carried out using 8 VS from different tissues, upon which a group of three pathologists had navigated. Precision-recall measurements were calculated at each step of any actual navigation, obtaining an average precision of 55% and a recall of about 38% when using the available set of navigations

Classification of functional data: a weighted distance approach

A popular approach for classifying functional data is based on the distances from the function or its derivatives to group representative (usually the mean) functions or their derivatives. In this paper, we propose using a combination of those distances. Simulation studies show that our procedure performs very well, resulting in smaller testing classication errors. Applications to real data show that our procedure performs as well as –and in some cases better than– other classication methods

Trilingualism in the United States: A case study of an Arabic and Greek household

Recent studies suggest that trilingual families in the United States are experiencing limited resources due to failing efforts to promote heritage language (HL) maintenance, diversity, and language rights both nationally and locally. Using a case study methodology, this paper will address obstacles identified in an interview with an Arabic speaking mother raising a trilingual child along with a Greek speaking partner while living in a monolingual society (U.S.). There is a need to uncover complex language practices and issues that different trilingual groups in the United States experience in order to preserve their heritage languages (HL) and cultures. Qualitative data was based on a survey and a 70-minute long virtual interview conducted in 2022. Our case study analysis reveals that the child lacks cultural context to both HLs when learning them in a monolingual society. Nonetheless, our findings suggest that there seems to be a link between emotional investment and language development. The child’s closer relationship with the father’s family reports a faster HL acquisition and retention as opposed to the distant and limited interaction with the mother’s family. Additionally, data suggests that the child found it hard to build his own identity without the help of others who share the same cultures. This research aims to contribute to language policy reform nationally, which is necessary to provide children from diverse backgrounds in the United States with an inclusive, integrated education

Lo bueno, lo malo y lo feo de la propuesta Yasuní-ITT

La propuesta de mantener el crudo bajo tierra en el bloque ITT dentro de la Reserva de Biósfera Yasuní representa un gran oportunidad para demostrar al planeta que los ecuatorianos estamos dispuestos a cambiar nuestro actual modelo de desarrollo. La falta de una decisión política firme hace tambalear a la propuesta. ¿Quiénes perdemos o ganamos con esto?. El Parque y la Reserva de Biosfera Yasuní encierran la mayor concentración de biodiversidad por kilómetro cuadrado de todos los lugares del planeta. Varios científicos que han venido trabajando desde los años noventa en las estaciones Yasuní de la PUCE, pero sobre todo en la Estación de Bio-diversidad Tiputini de la USFQ, plasmaron esta conclusión en un artículo científico publicado en la revista científica PLoSONE a finales del 2009. En una hectárea de bosque se pueden encontrar más del doble de especies de árboles que en el territorio de los Estados Unidos continental o toda Europa. Aquí habita la mayor diversidad registrada de anfibios y reptiles de ningún otro lugar de la Amazonía. Con sus más de 630 especies de aves, representa casi la mitad de la diversidad de aves del Ecuador y no tiene igual en el mundo.La propuesta de mantener el crudo bajo tierra en el bloque ITT dentro de la Reserva de Biósfera Yasuní representa un gran oportunidad para demostrar al planeta que los ecuatorianos estamos dispuestos a cambiar nuestro actual modelo de desarrollo. La falta de una decisión política firme hace tambalear a la propuesta. ¿Quiénes perdemos o ganamos con esto?. El Parque y la Reserva de Biosfera Yasuní encierran la mayor concentración de biodiversidad por kilómetro cuadrado de todos los lugares del planeta. Varios científicos que han venido trabajando desde los años noventa en las estaciones Yasuní de la PUCE, pero sobre todo en la Estación de Bio-diversidad Tiputini de la USFQ, plasmaron esta conclusión en un artículo científico publicado en la revista científica PLoSONE a finales del 2009. En una hectárea de bosque se pueden encontrar más del doble de especies de árboles que en el territorio de los Estados Unidos continental o toda Europa. Aquí habita la mayor diversidad registrada de anfibios y reptiles de ningún otro lugar de la Amazonía. Con sus más de 630 especies de aves, representa casi la mitad de la diversidad de aves del Ecuador y no tiene igual en el mundo

Using CycleGANs for effectively reducing image variability across OCT devices and improving retinal fluid segmentation

Optical coherence tomography (OCT) has become the most important imaging modality in ophthalmology. A substantial amount of research has recently been devoted to the development of machine learning (ML) models for the identification and quantification of pathological features in OCT images. Among the several sources of variability the ML models have to deal with, a major factor is the acquisition device, which can limit the ML model's generalizability. In this paper, we propose to reduce the image variability across different OCT devices (Spectralis and Cirrus) by using CycleGAN, an unsupervised unpaired image transformation algorithm. The usefulness of this approach is evaluated in the setting of retinal fluid segmentation, namely intraretinal cystoid fluid (IRC) and subretinal fluid (SRF). First, we train a segmentation model on images acquired with a source OCT device. Then we evaluate the model on (1) source, (2) target and (3) transformed versions of the target OCT images. The presented transformation strategy shows an F1 score of 0.4 (0.51) for IRC (SRF) segmentations. Compared with traditional transformation approaches, this means an F1 score gain of 0.2 (0.12).Comment: * Contributed equally (order was defined by flipping a coin) --------------- Accepted for publication in the "IEEE International Symposium on Biomedical Imaging (ISBI) 2019