Elemental Analysis of Adhesive Tapes by Laser-Based Methods

Adhesive tapes are a common type of evidence involved in violent crimes and national security threats. This research evaluated the utility of LA-ICP-MS and LIBS for the characterization of the trace elemental signature in adhesive tapes for forensic comparisons. LA-ICP-MS and LIBS methods were developed, for the first time, for the qualitative and quantitative analysis of adhesive tapes. The backings of 90 black electrical tapes, previously characterized by conventional techniques (physical examination, IR, Py-GC-MS, and SEM-EDS), were analyzed by LA-ICP-MS to evaluate the ability of the technique to discriminate samples originating from different sources and to associate pieces of tapes originating from the same roll. The discrimination for the LA-ICP-MS analysis of the 90 samples was found to be 93.9%, greater than the discrimination found using SEM-EDS (87.3%). Moreover, 100% correct association resulted for the control samples evaluated in this study. The analysis of tapes by LIBS allowed to separate pairs of tapes that were not previously distinguished by LA-ICP-MS by detecting differences in lithium, calcium, and potassium. The potential of normalization strategies was evaluated for LIBS spectral and statistical comparisons. Two quantitative analysis methods were developed for the analysis of tapes and other polymers. These quantitative methods can help in creating and populating databases that can lead to the use of likelihood ratios and the development of standard methods of analysis and interpretation for tape evidence. Two interlaboratory trials including 7 operational and research laboratories were completed as part of this study. SEM-EDS resulted in 16.7% and 12.5% false positive rates for interlaboratory tests #1 and #2, respectively. Up to 7 and 8 elements were detected by SEM-EDS for interlaboratory test #1 and #2, respectively. LIBS and LA-ICP-MS resulted in no false positives or false negatives. In addition, increased characterization of the samples was obtained by detecting up to 17 elements by LIBS and 32 elements by LA-ICP-MS. The increased sensitivity and selectivity of LIBS and LA-ICP-MS methods has been shown to distinguish tapes originating from different sources, and to correctly associate tapes belonging to the same rolls in different laboratories and by different analysts

Implementación del Monitoreo de opciones de Agricultura Sostenible Adaptada al Clima (ASAC): Seguimiento a su adopción e impactos en el TeSAC de Olopa, Guatemala – febrero 2020 Reporte de Actividad

Este documento presenta los resultados de la implementación del Marco de monitoreo multinivel sobre Agricultura Sostenible Adaptada al Clima (ASAC), en el TeSAC de Olopa en Guatemala. Este monitoreo ha permitido generar evidencia sobre la adopción de prácticas y tecnologías agrícolas viables y climáticamente inteligentes implementadas en el territorio. Además, otro objetivo del monitoreo fue evaluar el efecto que tiene la implementación de prácticas ASAC en la seguridad alimentaria, los medios de vida de los hogares y varias dimensiones de género. Para ello se recopiló información sobre las características socioeconómicas de 106 hogares y 187 agricultores (84 mujeres y 103 hombres), su percepción ante el efecto de eventos climáticos y la implementación de prácticas ASAC, entre otros aspectos

The Uneven Influence of Climate Trends and Agricultural Policies on Maize Production in the Yucatan Peninsula, Mexico

Maize is an important staple crop in Mexico, and the recent intensification of climate variability, in combination with non-climatic forces, has hindered increases in production, especially for smallholder farmers. This article demonstrates the influence of these drivers on maize production trends in the three states of the Yucatan Peninsula using a mixed methods approach of climatic analysis and semi-structured interviews. Climate trend analysis and generalized additive models (GAMs) demonstrate relationships between production and climatic variability, using 1980–2010 precipitation and temperature data. Data from forty interviews with government officials and representatives of farmers\u27 associations (gathered in 2015 and 2016) highlight the influence of agricultural policy on maize production in the region. The climate trend analysis yielded mixed results, with a statistically significant negative rainfall trend for Quintana Roo and variability in maximum temperature changes across the region, with an increase in Yucatan State and Quintana Roo and a decrease in Campeche. Climate and production GAMs indicate a strong significant relationship between production and climate fluctuations for Campeche (79%) and Quintana Roo (72%) and a weaker significant relationship for the Yucatan State (31%). Informants identified precipitation variability and ineffective public policies for smallholder agricultural development as primary obstacles for maize production, including inadequate design of agricultural programs, inconsistent agricultural support, and ineffective farmers\u27 organizations. Quantifying the influence of climate change on maize production, and the amplifying influence of national and regional agricultural policy for smallholder farmers, will inform more appropriate policy design and implementation

Plataforma de Colaboración para la Investigación

En cuanto al uso de los conceptos para organizar el conocimiento, Hjorland indica que éstos son concebidos como unidades de pensamiento, y la relación interconceptual es un elemento fundamental ya que los paradigmas, con sus teorías y conceptualizaciones, son por naturaleza instrumentos clasificadores de la realidad con la que interactúa de continuo el individuo. De esta forma, las relaciones semánticas que se establecen entre los conceptos son básicas para sistematizar el conocimiento, pero su significado queda sujeto a la perspectiva teórica desde la cual sean considerados.Según la UNESCO (2005a) la diversidad de las modalidades de acceso al conocimiento constituye una de las características más importantes de la sociedad del aprendizaje y supone también, entre otras cosas, el cuestionamiento de los conceptos de inteligencia en los que prevalecía el carácter estable de los procesos de evaluación y trasmisión de los conocimientos. Así, en el contexto de la realidad actual, la tarea de discriminar información se vuelve un proceso casi imposible, la creciente información actual, principalmente por vía Internet, le resulta al pensamiento humano cada vez más difícil de filtrar, tratar y dominar; lo cual se traduce en barreras (número ilimitado de fuentes, desconocimiento de los mecanismos de filtrado, organización o apropiación cognitiva de la información) que impiden hacer un uso efectivo de ella. Así, el exceso de información no significa mejor comprensión de la realidad, sino que con frecuencia alarmante produce el efecto contrario (UNESCO, 2005a; Dudziacck 2003; Sahagún, 2004, citados por Peña, 2011)

Resilience to the effects of social stress on vulnerability to developing drug addiction

We review the still scarce but growing literature on resilience to the effects of social stress on the rewarding properties of drugs of abuse. We define the concept of resilience and how it is applied to the field of drug addiction research. We also describe the internal and external protective factors associated with resilience, such as individual behavioral traits and social support. We then explain the physiological response to stress and how it is modulated by resilience factors. In the subsequent section, we describe the animal models commonly used in the study of resilience to social stress, and we focus on the effects of chronic social defeat (SD), a kind of stress induced by repeated experience of defeat in an agonistic encounter, on different animal behaviors (depression- and anxiety-like behavior, cognitive impairment and addiction-like symptoms). We then summarize the current knowledge on the neurobiological substrates of resilience derived from studies of resilience to the effects of chronic SD stress on depression- and anxiety-related behaviors in rodents. Finally, we focus on the limited studies carried out to explore resilience to the effects of SD stress on the rewarding properties of drugs of abuse, describing the current state of knowledge and suggesting future research directions

Wikification of learning objects using metadata as an alternative context for disambiguation

We present a methodology to wikify learning objects. Our proposal is focused on two processes: word sense disambiguation and relevant phrase selection. The disambiguation process involves the use of the learning objects metadata as either additional or alternative context. This increases the probability of success when a learning object has a low quality context. The selection of relevant phrases is perf ormed by identifying the highest values of semantic relat edness between the main subject of a learning object and t he phrases. This criterion is useful for achieving the didactic objectives of the learning object

Manual de implementación de prácticas de Agricultura Sostenible Adaptada al Clima (ASAC). Experiencias de los TeSAC de Guatemala y Honduras.

Este manual recoge algunas de las prácticas agropecuarias implementadas en el TeSAC de Olopa (en las comunidades de El Guayabo, Nochán, Tituque (Caserío Tishmuntique y Tuticopote abajo), así como en el TeSAC de Santa Rita, (en las comunidades de Tierra Fría, La Casita, Aldea nueva, Queseras y Villanueva). Dichas prácticas son el resultado de un esfuerzo entre las comunidades mencionadas, CCAFS y sus socios implementadores tanto en Guatemala (la Asociación Regional Campesina Ch'orti' - ASORECH), como en Honduras (la Comisión de Acción Social Menonita - CASM)

Xanthinuria: a rare cause of urolithiasis in the cat

Xanthinuria is a very rare disease in cats. Its etiology may have a genetic origin or may be due to an iatrogenic xan- thine-dehydrogenase inhibition that nally results in urolithiasis. The present work reports two cases of xanthine uro- lithiasis in European Shorthair unrelated male and female cats. Both uroliths were analyzed by stereoscopic microsco- py, infrared spectroscopy and scanning electron microscopy. Besides the report of these two clinical cases, a detailed pathophysiologic review and some updated recommendations for diagnosis and treatment for this condition were done.La xantinuria es una patología que se presenta raramente en los gatos. Su etiología puede tener origen genético o de- berse a una inhibición yatrogénica de la enzima xantina deshidrogenasa, que generalmente se mani esta con urolitiasis. En este trabajo se informa el hallazgo de dos urolitos de xantina en dos gatos, un macho y una hembra, de raza Euro- pea de pelo corto, no emparentados. Los urolitos fueron analizados mediante microscopía estereoscópica, espectrosco- pía infrarroja y microscopía electrónica de barrido. Además de informar sobre estos casos clínicos, se hace una revisión detallada de la siopatología y de las recomendaciones actuales para el diagnóstico y manejo médico de esta patología.Se agradece al Consejo Nacional de Ciencia y Tecnolo- gía de México (CONACyT) y al Programa de Mejora- miento del Profesorado de la Secretaria de Educación Pública de México 2011 (PROMEP-SEP), el apoyo complementario para la realización de este trabajo

Formative E-Assessment of Schema Acquisition in the Human Lexicon as a Tool in Adaptive Online Instruction

This chapter presents a comprehensive method of implementing e-assessment in adaptive e-instruction systems. Specifically, a neural net classifier capable of discerning whether a student has integrated new schema-related concepts from course content into her/his lexicon is used by an expert system with a database containing natural mental representations from course content obtained from students and teachers for adapting e-instruction. Mental representation modeling is used to improve student modeling. Implications for adaptive hypermedia systems and hypertext-based instructions are discussed. Furthermore, it is argued that the current research constitutes a new cognitive science empirical direction to evaluate knowledge acquisition based on meaning information

Cognitive Analysis of Meaning and Acquired Mental Representations as an Alternative Measurement Method Technique to Innovate E-Assessment

Empirical directions to innovate e-assessments and to support the theoretical development of e-learning are discussed by presenting a new learning assessment system based on cognitive technology. Specifically, this system encompassing trained neural nets that can discriminate between students who successfully integrated new knowledge course content from students who did not successfully integrate this new knowledge (either because they tried short-term retention or did not acquire new knowledge). This neural network discrimination capacity is based on the idea that once a student has integrated new knowledge into long-term memory, this knowledge will be detected by computer-implemented semantic priming studies (before and after a course) containing schemata-related words from course content (which are obtained using a natural semantic network technique). The research results demonstrate the possibility of innovating e-assessments by implementing mutually constrained responsive and constructive cognitive techniques to evaluate online knowledge acquisition