Focus and social contagion of environmental organization advocacy on Twitter.

Agriculture, overexploitation, and urbanization remain the major threats to biodiversity in the Anthropocene. The attention these threats garner among leading environmental nongovernmental organizations (eNGOs) and the wider public is critical in fostering the political will necessary to reverse biodiversity declines worldwide. I analyzed the advocacy of leading eNGOs on Twitter by scraping account timelines, screening content for advocacy relating to biodiversity threats and, for prevalent threats, further screening content for positive and negative emotional language with a sentiment lexicon. Twitter advocacy was dominated by the major threats of climate change and overexploitation and the minor threat of plastic pollution. The major threats of agriculture, urbanization, invasions, and pollution were rarely addressed. Content relating to overexploitation and plastic pollution was more socially contagious than other content. Increasing emotional negativity further increased social contagion, whereas increasing emotional positivity did not. Scientists, policy makers, and eNGOs should consider how narrowly focused advocacy on platforms like Twitter will contribute to effective global biodiversity conservation.

Enfoque y Contagio Social de la Promoción de Organizaciones Ambientales en Twitter Resumen La agricultura, la sobreexplotación y la urbanización siguen siendo las principales amenazas para la biodiversidad durante el Antropoceno. La atención que atraen estas amenazas entre las principales organizaciones no gubernamentales ambientales (ONGa) y el público en general es crítico para el fomento de la voluntad política necesaria para revertir las declinaciones en la biodiversidad a nivel mundial. Analicé la promoción de las principales ONGa en Twitter mediante la extracción de información de la cronología de las cuentas, la búsqueda de contenidos de promoción relacionados con las amenazas para la biodiversidad y el lenguaje emocional negativo con un léxico de opinión. La promoción en Twitter estuvo dominada por dos amenazas predominantes y una amenaza menor: el cambio climático y la sobreexplotación y la contaminación por plástico, respectivamente. Las amenazas predominantes como la agricultura, la urbanización, las invasiones y la contaminación fueron mencionadas en raras ocasiones. El contenido relacionado con la sobreexplotación y la contaminación por plástico tuvo un mayor contagio social que cualquier otro contenido. El incremento en la negatividad emocional incrementó todavía más el contagio social, mientras que el incremento en la positividad emocional no lo hizo. Los científicos, los formuladores de políticas y las ONGa deberían considerar cómo contribuirá la promoción, con un enfoque casi exclusivo en plataformas como Twitter, a la conservación efectiva de la biodiversidad en todo el mundo.

Biomass encounter rates limit the size scaling of feeding interactions.

The rate that consumers encounter resources in space necessarily limits the strength of feeding interactions that shape ecosystems. To explore the link between encounters and feeding, we first compiled the largest available dataset of interactions in the marine benthos by extracting data from published studies and generating new data. These data indicate that the size-scaling of feeding interactions varies among consumer groups using different strategies (passive or active) to encounter different resource types (mobile or static), with filter feeders exhibiting the weakest feeding interactions. Next, we used these data to develop an agent-based model of resource biomass encounter rates, underpinned by consumer encounter strategy and resource biomass density. Our model demonstrates that passive strategies for encountering small, dispersed resources limits biomass encounter rates, necessarily limiting the strength of feeding interactions. Our model is based on generalisable assumptions, providing a framework to assess encounter-based drivers of consumption and coexistence across systems.

Functional responses of a cosmopolitan invader demonstrate intraspecific variability in consumer-resource dynamics.

BACKGROUND: Variability in the ecological impacts of invasive species across their geographical ranges may decrease the accuracy of risk assessments. Comparative functional response analysis can be used to estimate invasive consumer-resource dynamics, explain impact variability, and thus potentially inform impact predictions. The European green crab (Carcinus maenas) has been introduced on multiple continents beyond its native range, although its ecological impacts appear to vary among populations and regions. Our aim was to test whether consumer-resource dynamics under standardized conditions are similarly variable across the current geographic distribution of green crab, and to identify correlated morphological features. METHODS: Crabs were collected from multiple populations within both native (Northern Ireland) and invasive regions (South Africa and Canada). Their functional responses to local mussels (Mytilus spp.) were tested. Attack rates and handling times were compared among green crab populations within each region, and among regions (Pacific Canada, Atlantic Canada, South Africa, and Northern Ireland). The effect of predator and prey morphology on prey consumption was investigated. RESULTS: Across regions, green crabs consumed prey according to a Type II (hyperbolic) functional response curve. Attack rates (i.e., the rate at which a predator finds and attacks prey), handling times and maximum feeding rates differed among regions. There was a trend toward higher attack rates in invasive than in native populations. Green crabs from Canada had lower handling times and thus higher maximum feeding rates than those from South Africa and Northern Ireland. Canadian and Northern Ireland crabs had significantly larger claws than South African crabs. Claw size was a more important predictor of the proportion of mussels killed than prey shell strength. DISCUSSION: The differences in functional response between regions reflect observed impacts of green crabs in the wild. This suggests that an understanding of consumer-resource dynamics (e.g., the per capita measure of predation), derived from simple, standardized experiments, might yield useful predictions of invader impacts across geographical ranges.

On the context-dependent scaling of consumer feeding rates.

The stability of consumer-resource systems can depend on the form of feeding interactions (i.e. functional responses). Size-based models predict interactions - and thus stability - based on consumer-resource size ratios. However, little is known about how interaction contexts (e.g. simple or complex habitats) might alter scaling relationships. Addressing this, we experimentally measured interactions between a large size range of aquatic predators (4-6400 mg over 1347 feeding trials) and an invasive prey that transitions among habitats: from the water column (3D interactions) to simple and complex benthic substrates (2D interactions). Simple and complex substrates mediated successive reductions in capture rates - particularly around the unimodal optimum - and promoted prey population stability in model simulations. Many real consumer-resource systems transition between 2D and 3D interactions, and along complexity gradients. Thus, Context-Dependent Scaling (CDS) of feeding interactions could represent an unrecognised aspect of food webs, and quantifying the extent of CDS might enhance predictive ecology.

ZEB1 and TCF4 reciprocally modulate their transcriptional activities to regulate Wnt target gene expression.

The canonical Wnt pathway (TCF4/ß-catenin) has important roles during normal differentiation and in disease. Some Wnt functions depend on signaling gradients requiring the pathway to be tightly regulated. A key Wnt target is the transcription factor ZEB1 whose expression by cancer cells promotes tumor invasiveness by repressing the expression of epithelial specification markers and activating mesenchymal genes, including a number of Wnt targets such as LAMC2 and uPA. The ability of ZEB1 to activate/repress its target genes depends on its recruitment of corepressors (CtBP, BRG1) or coactivators (p300) although conditions under which ZEB1 binds these cofactors are not elucidated. Here, we show that TCF4 and ZEB1 reciprocally modulate each other's transcriptional activity: ZEB1 enhances TCF4/ß-catenin-mediated transcription and, in turn, Wnt signaling switches ZEB1 from a repressor into an activator. In colorectal cancer (CRC) cells with active Wnt signaling, ZEB1 enhances transcriptional activation of LAMC2 and uPA by TCF4/ß-catenin. However, in CRC cells with inactive Wnt, ZEB1 represses both genes. Reciprocal modulation of ZEB1 and TCF4 activities involves their binding to DNA and mutual interaction. Wnt signaling turns ZEB1 into an activator by replacing binding of CtBP/BRG1 in favor of p300. Using a mouse model of Wnt-induced intestinal tumorigenesis, we found that downregulation of ZEB1 reduces the expression of LAMC2 in vivo. These results identify a mechanism through which Wnt and ZEB1 transcriptional activities are modulated, offering new approaches in cancer therapy.

Fortune favours the bold: a higher predator reduces the impact of a native but not an invasive intermediate predator.

Emergent multiple predator effects (MPEs) might radically alter predictions of predatory impact that are based solely on the impact of individuals. In the context of biological invasions, determining if and how the individual-level impacts of invasive predators relates to their impacts in multiple-individual situations will inform understanding of how such impacts might propagate through recipient communities. Here, we use functional responses (the relationship between prey consumption rate and prey density) to compare the impacts of the invasive freshwater mysid crustacean Hemimysis anomala with a native counterpart Mysis salemaai when feeding on basal cladoceran prey (i) as individuals, (ii) in conspecific groups and (iii) in conspecific groups in the presence of a higher fish predator, Gasterosteus aculeatus. In the absence of the higher predator, the invader consumed significantly more basal prey than the native, and consumption was additive for both mysid species - that is, group consumption was predictable from individual-level consumption. Invaders and natives were themselves equally susceptible to predation when feeding with the higher fish predator, but an MPE occurred only between the natives and higher predator, where consumption of basal prey was significantly reduced. In contrast, consumption by the invaders and higher predator remained additive. The presence of a higher predator serves to exacerbate the existing difference in individual-level consumption between invasive and native mysids. We attribute the mechanism responsible for the MPE associated with the native to a trait-mediated indirect interaction, and further suggest that the relative indifference to predator threat on the part of the invader contributes to its success and impacts within invaded communities.

[The effect of age in a planning and arranging task ('Mexican pyramid') among schoolchildren]. / Efecto de la edad en una tarea de planificación y organización ('pirámide de México') en escolares.

AIM: To analyze the influence of age on the performance of a planning and organization task, two skills included in the executive functions. SUBJECTS AND METHODS: Performance of the task 'Mexican pyramid' from the Evaluacion Neuropsicologica Infantil (ENI) were analyzed on 239 school age children from México and Colombia, distributed in six age groups. Five measures were analyzed: number of correct designs, number of movements per design and execution time in the correct designs, number of correct designs built with the minimum of movements and its execution time. RESULTS: There was a significant effect of age on the five measures. Comparison between groups showed that younger children (5 to 6 years old) had a smaller number of correct designs, while children from 5 to 8 years old need more movements. Execution time showed a greater number of differences between groups. Analyzing the 11 items of the task, it was evident that difficulty level is related with the number of movements and the novelty of rules. CONCLUSIONS: Our results suggest that accuracy of performance, the number of moves as well as the speed of performance are useful markers of the development of the executive functions. Our results support the notion that the development of planning and organization; is fast in the first years of the school age, and it slows down on adolescence.

Efecto de la edad en una tarea de planificación y organización (‘pirámide de México’) en escolares / The effect of age in a planning and arranging task (‘Mexican Pyramid’) among school children

Objetivo. Conocer los cambios relacionados con la edad en una tarea de planificación y organización, como componentes de las funciones ejecutivas. Sujetos y métodos. Se analizó la ejecución en la ‘pirámide de México’ de la evaluación neuropsi-cológica infantil en 239 escolares de México y Colombia de 5 a 16 años de edad, distribuidos en seis grupos. Se utilizaron cinco medidas: número de aciertos, número de movimientos y tiempo de ejecución en los diseños correctos, número de aciertos y tiempo de ejecución en los diseños correctos realizados con el mínimo de movimientos. Resultados. Se observó un efecto de la edad sobre las cinco medidas. En comparación con los otros grupos, los niños de 5 a 6 años tienen una menorcantidad de diseños correctos; los de 5 a 8 años requieren mayor número de movimientos. El tiempo de ejecución mostró un mayor número de diferencias intragrupales. El análisis por ensayo reveló que el grado de dificultad se relaciona con la cantidadde movimientos y lo novedoso de las reglas. Conclusiones. Además del número de aciertos y de movimientos invertidos para lograr cada acierto, el tiempo de ejecución es un indicador útil del desarrollo de estas funciones, dado que la rapidez enla ejecución es la que marca diferencias mayores entre los niños. Nuestros resultados apoyan la existencia de un desarrollo acelerado de las funciones de planificación y organización durante los primeros años de la etapa escolar, que sigue un cursomás lento en la adolescencia

Aim. To analyze the influence of age on the performance of a planning and organization task, two skills includedin the executive functions. Subjects and methods. Performance of the task ‘Mexican pyramid’ from the Evaluación Neuropsicológica Infantil (ENI) were analyzed on 239 school age children from México and Colombia, distributed in six age groups.Five measures were analyzed: number of correct designs, number of movements per design and execution time in the correct designs, number of correct designs built with the minimum of movements and its execution time. Results. There was a significant effect of age on the five measures. Comparison between groups showed that younger children (5 to 6 years old) hada smaller number of correct designs, while children from 5 to 8 years old need more movements. Execution time showed a greater number of differences between groups. Analyzing the 11 items of the task, it was evident that difficulty level is related with the number of movements and the novelty of rules. Conclusions. Our results suggest that accuracy of performance, the number of moves as well as the speed of performance are useful markers of the development of the executive functions. Our results support the notion that the development of planning and organization; is fast in the first years of the school age, and it slows down on adolescence

[The nutritional status of the child with congenital cardiopathy]. / Estado nutricio del niño con cardiopatía congénita.

OBJECTIVE: To know the frequency and type of nutritional alterations of children with congenital heart disease. MATERIAL AND METHODS: Sixty six children with congenital heart disease were studied. MEASUREMENTS were: weight, size, mid arm circumference, tricipital and subscapular skinfold thickness. Blood samples for white blood cells count, and albumin were taken and urine was collected for determination of creatinine. Muscular and fat areas of the arm and creatinine/height index were calculated. In order to compare the children with both cyanotic and non-cyanotic types of heart diseases chi 2 test or Fisher's exact test, ware used. RESULTS: 41 girls and 25 boys, 42 with acyanotic and 24 cyanotic heart disease. 50 children were malnourished (26 compensated, 23 non-compensated and one acute); 16 were normal. 85% of the children presented diminished muscular area and 97% diminished fatty area. The creatinine/height index was diminished in 94% of the cases. No significant differences were demonstrated between both groups. CONCLUSION: chronic malnutrition in children with congenital heart disease is frequent. Most of the cases with malnutrition are compensated. This poor nutritional status is at the expense of fatty and muscular tissues.

[Structure of human resources in a public hospital in Chile: an experience in introducing changes]. / Estructura y recursos humanos en un hospital público chileno: una experiencia de cambio.

This article discusses the structural and operational reform process that took place beginning in 1994 in Luis Calvo Mackenna Hospital, a tertiary pediatric care facility run by Oriente Metropolitan Health Center in Santiago, Chile. The formation of the Chilean health care system is briefly outlined, along with the changes brought about by the military government in 1979 and other transformations introduced by the first democratic government in 1990 and by the second one, in 1994. In spite of Chile's favorable health indicators and of the current government's desire to establish equitable services and to launch a decentralized system, the health care system that was fundamentally modeled in the fifties and sixties has failed to respond successfully to the demographic transition and to the population's new epidemiologic profile. One of the main problems is that services at the secondary and tertiary levels lack what is necessary to respond to the demand. Under a new leadership with an interest in modern administrative methods, clinical services at Luis Calvo Mackenna Hospital were restructured with new departments and units, a study of the organizational climate was carried out, the entire staff was intensively trained so as to generate a spirit of involvement and a new vision of the hospital's mission and teamwork, and a strategic plan was drawn up that is still being implemented.

[Quantification of bacteria in the small intestine of malnourished children with chickenpox]. / Cuantificacíon de bacterias del intestino delgado en niños desnutridos con varicela.

The purpose of the present study was to determine whether a high number of bacteria could be demonstrated in the upper small bowel during the chickenpox infection. Intestinal juice was drawn in nine malnourished children, during and two weeks after the acute period of the disease. The results of the study fail to demonstrate quantitative differences in the bacterial flora of the small bowel in both periods. Besides that, the bacterial overgrowth previously reported in malnutrition, is confirmed.

Mejoramiento tecnológico de la producción de cachirí: bebida fermentada de Yuca (Manihot esculenta Crantz) do origen indígena / Technological improvement of the production of cachiri fermented beverage of cassava (Manihot esculenta Crantz) of indigenous origin

Se presenta una tecnología para la elaboración de cachirí (cachirí), bebida fermentada de yuca (Manihot esculenta Crantz) tradicionalmente consumida por algunas comunidades indígenas de Venezuela,Suriname y Guyana. En la tecnología propuesta se usó yuca fresca o harina de yuca como materia prima y el proceso comprendió tres etapas: 1) licuefacción, en la cual se utilizó alfa-amilasa y fue efectuada a 85-C y pH 6,0;2 sacarificación en la cual se empleó amiloglucosidasa y fue llevado a cabo a 60-C, pH 4,5; y 3) fermentación a 30-C y pH 4,5 empleando una levadura del género Saccharomyces. El mostro fermentado se clarificó, embotelló y pasteurizó. Esta bebida resultó ser un líquido de color ambar; de baja acidez (0,289g/100ml); con un nivel de etanol en el rango de 8,86 al 13,8% v/v y azúcares totales de 2.12% respectivamente. Las concentraciones de acetato de etilo, alcohol propílico, butílico y amílico, etc., fueron muy similares a los encontrados frecuentemente en vinos tradicionales