186 research outputs found
Measuring Photosynthesis in Symbiotic Invertebrates: A Review of Methodologies, Rates and Processes
Assessment of habitat quality and landscape connectivity for forest-dependent cracids in the Sierra Madre del Sur Mesoamerican biological corridor, Mexico
Assessing landscape connectivity allows us to identify critical areas that impede or facilitate the movement of organisms and their genes and to plan their conservation and management. In this article, we assessed landscape connectivity and ecological condition of the habitat patches of a highly biodiverse region in Chiapas, Mexico. We employed data of three cracid species with different characteristics in habitat use and mobility. The habitat map of each species was derived from a spatial intersection of the models of potential distribution and a high-resolution map of current land cover and land use. The ecological condition of vegetation types was evaluated using 75 field plots. Structure of landscape was estimated by fragmentation metrics, while functional connectivity was assessed using spatially explicit graph analysis. The extent of suitable habitat for Oreophasis derbianus, Penelopina nigra, and Penelope purpurascens correspond to 25%, 46%, and 55% of the study area (5,185.6 km2), respectively. Although the pine-oak forests were the most fragmented vegetation type, habitats of the three species were well connected, and only 4% to 9% of the fragments located on the periphery of the corridor had low connectivity. Landscape connectivity depends mainly on land uses with an intermediate and lower ecological condition (secondary forests and coffee agroforestry systems). Therefore, we suggest that in addition to promoting the improvement in connectivity in fragmented forests, conservation efforts should be aimed at preventing the conversion of mature forests into agricultural uses and maintaining agroforestry systems
Diseño e implementación de una universidad abierta caso Universidad Central del Ecuador
La Universidad del Central del Ecuador se encuentra en un cambio trascendental en su vida institucional con el fin de retomar la categoría A en la evaluación del CEAACES. Esta acreditación tiene un componente importante en el desarrollo de la investigación y conocimiento. Considerando estos aspectos, se ha diseñado una propuesta basada en el uso de la tecnología y que ha sido implementada como una estrategia integral, orientada hacia una universidad abierta que permita sustentar los principios de Transparencia, Participación, Colaboración. El logro de esta estrategia está supeditado a la implementación de tecnología de punta que consolide estos principios en el seno de la comunidad universitaria. Este artículo detalla las etapas a implementarse en una Universidad Abierta, considerando los siguientes momentos: estado del arte, descripción del proyecto, metas logradas, siguientes pasos, y un resumen de las lecciones aprendidas. Se presenta la experiencia de implementación de los proyectos que soportan la estrategia y cómo ellos se han ido diseñando e implementando
Structural complexity governs seagrass acclimatization to depth with relevant consequences for meadow production, macrophyte diversity and habitat carbon storage capacity
Analyses of the integrated seagrass response to depth support the previously documented low plasticity and consistent shade-adapted leaf physiology of a habitat-builder that dominates well-illuminated reef environments. Two structural responses, "canopy-opening" and "below-ground-mass-depletion", govern the photoacclimatory response and facilitate, respectively, light penetration within the canopy and functional adjustments in whole-plant carbon balances. Conversely, "canopy-closing" may also explain dense canopies formed close to the waterline, as they provide shade and photoprotection to a susceptible leaf physiology under high-light. Canopy light attenuation is primarily regulated by the leaf area index (LAI), which is governed by changes in shoot size and density. Shoot density diminishes non-linearly with depth, while shoot size increases to a maximum followed by a decline. The initial increase in shoot size, which resembles a self-thinning response, increases LAI and meadow production in shallow depths. These seagrass structural adjustments have relevant ecological implications. Canopy-thinning allows macrophyte diversity to increase with depth, while seagrass production and carbon storage diminish exponentially, and are maximal only in a shallow coastal fringe. The results support the universality of plant self-thinning, from phytoplankton to complex canopies, likely the consequence of simple physical laws related to light limitation and pigment self-shading within photosynthetic structures and communities
Avaliação de um programa de intervenção para promover a saúde sexual de adolescentes mexicanos em conflito com a lei
O propósito desta pesquisa foi avaliar a efetividade de um programa de intervenção para promover a saúde sexual de adolescentes que se encontram em conflito com a lei. Trabalhou-se com 118 adolescentes pertencentes a uma comunidade de diagnóstico. Foi utilizado um desenho quase-experimental com um grupo de intervenção e um de controle, conformado por três fases: pré-avaliação, intervenção e pós-avaliação. A intervenção consistiu em cinco sessões de duas horas cada uma e foi formada pelos elementos que respondem ao modelo ecológico em seus três níveis: microssistema (conhecimentos, crenças, atitudes, intenção e autoeficácia para usar preservativo, autoestima, comunicação com o parceiro, estilos de negociação para usar preservativo, entre outros); mesossistema (apoio, supervisão e comunicação com os pais, entre outros) e macrossistema (estereótipos de gênero). Foi realizada uma análise de medidas repetidas. Os resultados mostraram mudanças entre o grupo controle e o experimental a favor deste último em todas as variáveis do modelo, exceto em comunicação com o parceiro e autoestima. Os achados são discutidos quanto à importância de desenhar programas com base no modelo ecológico dirigidos à população que se encontra num ambiente privado de liberdade.The purpose of this research was to evaluate the effectiveness of an intervention program to promote sexual health of adolescents in conflict with the law. The study was carried out with 118 adolescents belonging to a diagnosis community. A quasi-experimental design was used with an intervention group and one control group, consisting of three phases: preevaluation, intervention and post-evaluation. The intervention, which consisted of five sessions of two hours each one, comprised the elements that respond to the ecological model in its three levels: micro-system (knowledge, believes, attitudes, intentions and self-efficacy to use condoms, self-esteem, communication with partner, negotiating styles, etc.); meso-system (support, supervision and communication with parent, etc.) and macro-system (gender stereotypes). An analysis of repeated measures was performed. Results showed changes between control and experimental groups, in favor of the latter in all the variables of the model, except for partner communication and self-esteem. The findings are discussed in terms of the importance of designing programs based on the ecological model aimed at people who are deprived of freedom.El propósito de la presente investigación fue evaluar la efectividad de un programa de intervención para promover la salud sexual de adolescentes que se encuentran en conflicto con la ley. Se trabajó con 118 adolescentes pertenecientes a una comunidad de diagnóstico. Se utilizó un diseño cuasiexperimental con un grupo de intervención y uno control, conformado por tres fases: preevaluación, intervención y postevaluación. La intervención consistió en cinco sesiones de dos horas cada una, y estuvo conformada por los elementos que responden al modelo ecológico en sus tres niveles: microsistema (conocimientos, creencias, actitudes, intención y autoeficacia para usar condón, autoestima, comunicación con pareja, estilos de negociación para usar condón, entre otras); mesosistema (apoyo, supervisión y comunicación con padre y madre, entre otras), y macrosistema (estereotipos de género). Se realizó un análisis de medidas repetidas. Los resultados mostraron cambios entre el grupo control y el experimental, a favor de este último en todas las variables del modelo, excepto en comunicación con la pareja y autoestima. Los hallazgos se discuten en términos de la importancia de diseñar programas con base en el modelo ecológico dirigidos a población que se encuentran en un ambiente privado de la libertad
Fabricación de camisas para motores diesel
Conjunto de artículos publicados en la revista FundiPress sobre la fabricación de camisa
Comparar la eficiencia de las escalas de blatchford y rockall para predecir el riesgo de mortalidad y resangrado en pacientes con sangrado digestivo alto no variceal en el servicio de emergencia del Hospital Enrique Garcés
El Sangrado Digestivo Alto (SDA), se define como la perdida hemática proximal al ángulo de Treitz. Se manifiesta generalmente en forma de hematemesis o melenas, aunque ocasionalmente puede presentarse en forma de rectorragia. Constituye una urgencia potencialmente grave y sigue siendo una de las causas más frecuentes de hospitalización por patología digestiva (García-Castrillo Riesgo, Piñera Salmerón, Rancaño García, & Sánchez Sánchez, 2008; García Ruiz, Alcaín Martínez, Cañero, & Vazquez Pedreño, 2010).
La incidencia en Latinoamérica y referencial de Europa es de 102 por cada 100 000 hospitalizaciones. La mortalidad puede variar de 2% a 15% y en las nuevas hemorragias puede ser tan alta como 10 a 30%. De los pacientes que se presentan con la HDA, el 23% requiere transfusión de sangre, y el 14% necesitan intervención endoscópica o quirúrgica (García Ruiz, et al., 2010).
Los síntomas pueden ir desde: debilidad, cólicos abdominales, diarrea, palidez, hasta una hemorragia severa caracterizada por: ortostatismo, confusión, angina de pecho, palpitaciones severas, y extremidades frías/ húmedas (Church et al., 2006; García Ruiz, et al., 2010; Rotondano et al., 2014). Al examen físico podemos observar: sangre de color rojo intenso en el vómito, o con aspecto de pozos de café, heces negras o alquitranadas (melenas), sangre oscura mezclada en las heces, heces mezcladas o cubiertas con sangre de color rojo intenso (Cassana, Scialom, Segura, & Chacaltana, 2015; Chen, Hung, Chiu, Chen, & Hsiao, 2007; García Ruiz, et al., 2010; Rotondano, et al., 2014).
Se ha identificado como causas principales: úlcera péptica: dolor epigástrico o en el cuadrante superior derecho, úlcera de esófago: odinofagia, reflujo gastroesofágico, disfagia, mallory-weiss: emesis, arcadas, o toser antes de hematemesis, malignidad: disfagia, saciedad precoz, pérdida de peso involuntaria, caquexia (Church, et al., 2006), otras causas (Barkun, Bardou, Kuipers, et al., 2010).
Los instrumentos para dar puntajes de riesgo en SDA son: Puntuación de Rockall, Blatchford, AIM65 (Pang et al., 2010). La puntuación Rockall se basa en edad, la presencia de shock, comorbilidad, diagnóstico y estigmas endoscópicos de hemorragia reciente (Custódio Lima et al., 2013; Church et al., 2006; Espinoza Ríos et al., 2009; García-Castrillo Riesgo, et al., 2008; Hyett et al., 2013), la puntuación Blatchford, se basa en el nitrógeno ureico en sangre, la hemoglobina, la presión arterial sistólica, el pulso, y la
presencia de melena, síncope, enfermedad hepática e insuficiencia cardiaca (Blatchford, Murray, & Blatchford, 2000; Cheng, Lu, Teller, Sekhon, & Wu, 2012; Gallardo Chavarría, 2007; Gómez Herrera, 2008; Hyett, et al., 2013; Lanas et al., 2010; Saltzman, 2015), AIMS65 toma en cuenta cinco factores asociados con una mayor mortalidad hospitalaria: Albúmina menos de 3,0 g/dl (30 g/L), INR superior a 1,5, alteración del estado mental (Glasgow Coma Score de menos de 14, desorientación, letargo, estupor o coma), la presión arterial sistólica de 90 mmHg o menos, edad más de 65 años (Cheng, et al., 2012; Church, et al., 2006).
El tratamiento se basa en cuatro pilares fundamentales: Manejo de la vía aérea (según la clínica del paciente), hidratación, corrección hematocrito/hemoglobina, trastornos de coagulación (prolongación tiempos de coagulación. trombocitopenia) e inhibidores de la bomba de protones.
Este estudio es de corte transversal, se realizó un análisis de tipo descriptivo y de asociación entre las escalas. Las variables a medidas fueron Escalas de Blatchford y Rockal
Influence of size reduction of fly ash particles by grinding on the chemical properties of geopolymers
Chemical properties of geopolymers were evaluated from the reduction of fly ash particle size by grinding. X-ray diffraction determined that at early curing ages new crystalline phases appear in the matrix of the geopolymer and they remain for 28 days, with increases in intensities up to 60%. In Fourier transform infrared spectroscopy, displacements were identified in the main band of the geopolymers at higher wavenumbers, attributed to the greater rigidity in the structures of the aluminosilicate gel due to the increase of the reaction products in the geopolymers obtained through fly ashsubjected to previous grinding, which is observable in the geopolymers matrix. Results indicate that the reduction of fly ash particle size by grinding has an influence on the chemical properties of geopolymers.Peer ReviewedPostprint (published version
Scientific discourse in Early Childhood Education in the context of the Ecological School Garden
Desde el compromiso de promover la alfabetización científica desde edades tempranas, la siguiente
investigación tiene como objetivo explorar el funcionamiento del discurso científico de niños y niñas de 5 años
en momentos de asamblea y en el marco de una secuencia didáctica contextualizada en el huerto ecológico
escolar. Para ello, a partir de las transcripciones de cuatro asambleas se ha establecido un sistema de categorías
emergentes, aplicado sobre los datos y consensuado entre expertos. Los resultados muestran que los niños de 5
años aportan datos e información al discurso (31,6%), aportan esquemas de conocimiento (39,8%), argumentan
sobre los esquemas que comparten (24%) y en menor medida, hacen emerger modelos iniciales explicativos
(4,6%). Respecto a los esquemas de conocimiento que surgen, estos giran en torno a los elementos necesarios en
el huerto (luz, tierra, agua, profundidad), y permiten visualizar e inferir los modelos iniciales explicativos que
maneja el alumnado a estas edades. En conclusión, los resultados arrojan evidencias respecto de la capacidad de
desarrollar la competencia científica desde edades tempranas y la idoneidad del uso del huerto ecológico escolar
como contexto para la promoción de habilidades cognitivo lingüísticas que influyen en la construcción del
conocimiento científico.According to the necessity to develop scientific literacy from early ages, the aim of this work is to
explore scientific discourse of 5 years-old children at circle time during a didactic sequence related to their
ecological school garden. To get those achievements, an emergent-cathegories system has been stablished by the
analysis of transcriptions obtained from four circle time registrations, being this system agreed by experts. Results
show that 5 years-old children contributed with data and information to the discourse (in a 31,6% of the cases),
they supply knowledge schemata (in a 39,8% of the cases), they offer arguments on the shared schemata (in a
24% of the cases) and, in a less measure, they build initial explaning models (in a 4,6% of the cases). In relation
to knowledge schemata that are built in this context, they are about the necessary elements in the garden (light,
earth, water, soil or depth), and they allow to visualize and to infere the initial explaining models handled by the
children at that age. In conclusion, results show evidences respect to the capacity of developing scientific
competence from early years as well as the suitability of the use of ecological school garden as a context to
promote cognitive-linguistic skills which influence on scientific knowledge construction
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Age-related changes to the three-dimensional full shape of the isolated human crystalline lens
11 pags., 4 figs., 4 tabs.PURPOSE. Studying the full shape crystalline lens geometry is important to understand the changes undergone by the crystalline lens leading to presbyopia, cataract, or failure of emmetropization, and to aid in the design and selection of intraocular lenses and new strategies for correction. We used custom-developed three-dimensional (3-D) quantitative optical coherence tomography (OCT) to study age-related changes in the full shape of the isolated human crystalline lens. METHODS. A total of 103 ex vivo human isolated lenses from 87 subjects (age range, 0-56 years) were imaged using a 3-D spectral-domain OCT system. Lens models, constructed after segmentation of the surfaces and distortion correction, were used to automatically quantify central geometric parameters (lens thickness, radii of curvatures, and asphericities of anterior and posterior surfaces) and full shape parameters (lens volume, surface area, diameter, and equatorial plane position). Age-dependencies of these parameters were studied. RESULTS. Most of the measured parameters showed a biphasic behavior, statistically significantly increasing (radii of curvature, lens volume, surface area, diameter) or decreasing (asphericities, lens thickness) very fast in the first two decades of life, followed by a slow but significant increase after age 20 years (for all the parameters except for the posterior surface asphericity and the equatorial plane position, that remained constant). CONCLUSIONS. Three-dimensional quantitative OCT allowed us to study the age-dependency of geometric parameters of the full isolated human crystalline lens. We found that most of the lens geometric parameters showed a biphasic behavior, changing rapidly before age 20 years and with a slower linear growth thereafter.Supported by the Ministerio de Educación y Ciencia, Spain
(FIS2017- 84753-R), European Research Council (ERC-2011-
AdG-294099), and IMCUSTOMEYE Ref. 779960 (H2020-ICT2017-1) (SM), and European Research Council under Euro
pean Union’s Horizon 2020 research and innovation programme
H2020-MSCA COFUND-2015 FP-713694, MULTIPLY (AdC),
Consejo Superior de Investigaciones Científicas ICoop Program,
National Eye Institute (Grants 2R01EY021834, P30EY14801)
(Center Grant), the Hyderabad Eye Research Foundation,
Florida Lions Eye Bank and the Beauty of Sight Foundation,
and an unrestricted grant from Research to Prevent Blindnes
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