Escenario global: El medio digital como zona de encuentro y desencuentro : Una mirada a la narrativa de Hwajang de Im Kwon Taek

En la actualidad el medio digital ocupa gran parte del escenario cotidiano, ya sea como espacio de ocio o de estudio. Inicialmente se lo comprendía y asociaba a utilidades de mensajería, sin embargo con el pasar el tiempo, acompañado del avance tecnológico, fue adquiriendo un nuevo carácter en la realidad de los sujetos, ocupando funciones como la de albergar datos e información. Frente a ello nos insertamos en un mundo que está constantemente conectado y nos permite vislumbrar qué sucede en otras regiones territoriales, un contexto en el cual es necesario comprender el lugar de la globalización, entendiéndose desde el área digital como un proceso que trasciende los espacios tangibles y posibilita la difusión de conocimiento/información sin barrera. Si bien sabemos que el concepto de cultura es muy amplio, el presente trabajo parte de la concepción de la cultura como construcción social dinámica. Tanto así, que el sujeto en cuestión se sitúa al encuentro de la comprensión de la diversificación cultural. Es por esto último que considero fundamental la cultura como lo aparente desconocido, al medio digital como zona de encuentro, y al sujeto frente al texto, en su diversa aparición, como choque del encuentro/desencuentro. En consecuencia, comprender el contexto en el que se desenvuelve esta difusión de información/contenido se torna fundamental. Concebir el encuentro es entender que las culturas fluctúan y cambian a lo largo del tiempo, y por tanto no se trata de un juicio valorativo, sino más bien la construcción de un discurso crítico y situado frente al encuentro de un determinado texto, a los efectos de poder repensarlo con ojos contemporáneos. Pero ya la cuestión no solo radica en lo que el sujeto inserto/nosotros comprendamos y reconozcamos como cultura, sino también cuando el medio denomina lo que significa la “representación cultural”. Y he aquí una nueva interrogante ¿qué pasa cuando se promociona lo cultural?¿cuál es el límite entre la cultura y la autodenominada representación cultural? Es por esto último que se partirá de la narrativa de Hwajang (Im Kwon Taek, 2014) a los efectos de poder generar una lectura reflexiva, crítica y situada frente a la representación cultural que el director trabaja a través de su discurso. Para ello, invitar al sujeto a comprender el contexto para leer el texto.Centro de Estudios Coreano

Influence of the critical parameters on the density estimate of some fatty acids by the Rackett's method

9 páginas, 3 figuras, 3 tablas.[ES] En este trabajo se realiza un estudio comparativo de las propiedades críticas temperatura y presión en los ácidos grasos palmítico, esteárico y oléico, proporcionadas por diferentes fuentes bibliográficas. Estas propiedades se utilizan en la ecuación de Rackett para estimar la densidad de las sustancias puras. Se describen y emplean los métodos más comúnmente aplicados en estos casos para estimar dichas propiedades críticas. Se selecciona un conjunto de valores de propiedades críticas para aplicarlas en la estimación de la densidad por la ecuación de Rackett. Se proponen los valores de las propiedades críticas con los que se obtiene una mejor estimación de la densidad, cuando se compara con resultados experimentales. Se demuestra que la selección de las propiedades críticas influye de forma decisiva en la estimación de propiedades físicas mediante la ecuación de Rackett.[EN] In this work a comparative study is carried out of the critical properties of temperature and pressure applied for the palmitic, stearic and oleic fatty acids, provided by different bibliographical sources. These properties are used in the Rackett's equation to estimate the density of the pure substances. The most commonly employed methods are described and applied in these cases to estimate these critical properties. A group of values of critical properties is selected to estimate the density using the Rackett's equation. The values of the critical properties that give a better estimation of the density, according to Rackett's equation, when compared with the experimental results are proposed. It is demonstrated that the selection of the critical properties influences in a decisive way in the estimation of physical properties by means of the Rackett's equation.Los autores hacen constar su agradecimiento a: La Comisión Interministerial de Ciencia y Tecnología, por la ayuda recibida para la realización de este trabajo: ALI 95 0517. Al Instituto de Cooperación Iberoamericana (ICI), por la beca proporcionada para la realización de la Tesis Doctoral.Peer reviewe

Handling missing values in trait data

Aim: Trait data are widely used in ecological and evolutionary phylogenetic comparative studies, but often values are not available for all species of interest. Traditionally, researchers have excluded species without data from analyses, but estimation of missing values using imputation has been proposed as a better approach. However, imputation methods have largely been designed for randomly missing data, whereas trait data are often not missing at random (e.g., more data for bigger species). Here, we evaluate the performance of approaches for handling missing values when considering biased datasets. Location: Any. Time period: Any. Major taxa studied: Any. Methods: We simulated continuous traits and separate response variables to test the performance of nine imputation methods and complete-case analysis (excluding missing values from the dataset) under biased missing data scenarios. We characterized performance by estimating the error in imputed trait values (deviation from the true value) and inferred trait–response relationships (deviation from the true relationship between a trait and response). Results: Generally, Rphylopars imputation produced the most accurate estimate of missing values and best preserved the response–trait slope. However, estimates of missing data were still inaccurate, even with only 5% of values missing. Under severe biases, errors were high with every approach. Imputation was not always the best option, with complete-case analysis frequently outperforming Mice imputation and, to a lesser degree, BHPMF imputation. Mice, a popular approach, performed poorly when the response variable was excluded from the imputation model. Main conclusions: Imputation can handle missing data effectively in some conditions but is not always the best solution. None of the methods we tested could deal effectively with severe biases, which can be common in trait datasets. We recommend rigorous data checking for biases before and after imputation and propose variables that can assist researchers working with incomplete datasets to detect data biases and minimize errors.Fil: Johnson, Thomas F.. University of Reading; Reino UnidoFil: Isaac, Nick J. B.. Centre For Ecology And Hydrology; Reino UnidoFil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: González Suárez, Manuela. University of Reading; Reino Unid

Human Disturbance Influences Reproductive Success and Growth Rate in California Sea Lions (Zalophus californianus)

The environment is currently undergoing changes at both global (e.g., climate change) and local (e.g., tourism, pollution, habitat modification) scales that have the capacity to affect the viability of animal and plant populations. Many of these changes, such as human disturbance, have an anthropogenic origin and therefore may be mitigated by management action. To do so requires an understanding of the impact of human activities and changing environmental conditions on population dynamics. We investigated the influence of human activity on important life history parameters (reproductive rate, and body condition, and growth rate of neonate pups) for California sea lions (Zalophus californianus) in the Gulf of California, Mexico. Increased human presence was associated with lower reproductive rates, which translated into reduced long-term population growth rates and suggested that human activities are a disturbance that could lead to population declines. We also observed higher body growth rates in pups with increased exposure to humans. Increased growth rates in pups may reflect a density dependent response to declining reproductive rates (e.g., decreased competition for resources). Our results highlight the potentially complex changes in life history parameters that may result from human disturbance, and their implication for population dynamics. We recommend careful monitoring of human activities in the Gulf of California and emphasize the importance of management strategies that explicitly consider the potential impact of human activities such as ecotourism on vertebrate populations

Landscape and road features linked to wildlife mortality in the Amazon

Roads impact wildlife around the world; however, dedicated studies are lacking in many biodiverse areas such as the Amazon. Identifying which species are more often hit by vehicles and which landscape and road-related features promote roadkill is essential to guide future development and ensure adequate mitigation actions. For six months, we monitored 240 km of roads in the Ecuadorian Amazon and recorded 1125 dead vertebrates (149 species). Reptiles were the most observed Class with 380 individuals (56 species), followed by amphibians with 278 individuals (11 species), birds with 259 individuals (62 species), and mammals with 208 individuals (20 species). We used Random Forest models to explore the role of various land cover types and road sinuosity on the observed mortality. Additionally, we created heatmaps to visualize the road segments where roadkills were more frequent. For all vertebrates, mortality was more likely in straight road sections near rivers. The effects of other variables were taxa-specific. Amphibian mortality was more likely near bare soil or forest, birds and mammals died more often near herbaceous-shrubby vegetation, and reptile mortality occurred more often in areas with high cover of agriculture. Road segments with high mortality (i.e., roadkill hotspots) varied across taxa. These hotspots identify areas where further research into mitigation is needed to assess road impacts and prevent collisions. Among records, we found rare and threatened species, for which road mortality could be a significant threat. Roadkill surveys not only aid in quantifying threats and informing future planning but can also provide insight into local biodiversity

Socioeconomic factors predict population changes of large carnivores better than climate change or habitat loss

Land-use and climate change have been linked to changes in wildlife populations, but the role of socioeconomic factors in driving declines, and promoting population recoveries, remains relatively unexplored. Here, we evaluate potential drivers of population changes observed in 50 species of some of the world’s most charismatic and functionally important fauna—large mammalian carnivores. Our results reveal that human socioeconomic development is more associated with carnivore population declines than habitat loss or climate change. Rapid increases in socioeconomic development are linked to sharp population declines, but, importantly, once development slows, carnivore populations have the potential to recover. The context- and threshold-dependent links between human development and wildlife population health are challenges to the achievement of the UN Sustainable development goals

Ectoparasitoid Dinarmus basalis causes greater offspring loss to the winged morph of Callosobruchus maculatus

The pest cowpea weevil Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) exhibits polymorphism with flight and flightless forms that differ in morphology and life-history. Flight forms are generally dispersers with lower fecundity that increase in frequency when population density and intraspecific competition are both high. Callosobruchus maculatus larvae can cause important damage to stored grains and the solitary ectoparasitoid Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae) is considered to be a good candidate biological control agent. However, whether morphs differ in the likelihood of their offspring surviving attack is unknown. Understanding this has implications for the pest status of the cowpea weevil following biological control. We found that attack by D. basalis lowered the number of emerging offspring produced by both morphs. The ectoparasitoid was most effective at reducing survival of larvae produced by flight morph parents, suggesting that there may be a further cost of dispersal for C. maculatus. Parental morph type did not influence D. basalis behavior or development when foraging, so the biological mechanism resulting in this difference remains unclear. Nevertheless, our study shows that D. basalis affects the offspring of both weevil morphs, as required for an effective biocontrol agent. These results contribute to our understanding of how intraspecific variation, including polymorphism, influences species interactions among biological control agents and their target insect pests

Population abundance and density estimates for Costa Rica’s endemic sea snake, Hydrophis platurus xanthos

Population abundance and density estimates provide key information for conservation assessment and prioritization of efforts and management. However, data are still largely unavailable for many taxa, including sea snakes, which appear to be facing global declines. Here, we present the first quantitative abundance and density estimates for the geographically isolated sea snake Hydrophis platurus xanthos endemic to the inner basin of Golfo Dulce, Costa Rica. Using systematic distance sampling methods, we obtained and analyzed 199 snake detections from 46 transect lines covering the entire known distribution (totaling nine days and 469 km of effort). Our modeling methods accounted for (i) the probability of detecting a snake given it was available to be detected (ii) the average availability of snakes at the water surface during a 24-hr cycle, and (iii) the by-hour variance in the taxon’s activity pattern. The best estimate of population abundance was 29781 individuals (95% CI=20104–44115) with an estimated density of 76 snakes/ km2. Without historical abundance estimates or minimum viable population size, it is unknown whether this number represents a healthy population. However, with all individuals inhabiting a relatively small inlet increasingly exposed to anthropogenic impacts, the long-term persistence of H. p. xanthos may be threatened by ongoing impacts (boat propeller strikes, agricultural runoff, and climate change), as well as unforeseen events in the future

Effect of humidity and temperature on the performance of three strains of Aphalara itadori, a biocontrol agent for Japanese knotweed

Japanese knotweed (Fallopia japonica) is a highly damaging invasive species affecting UK infrastructure and biodiversity. Under laboratory conditions, the psyllid Aphalara itadori has demonstrated its potential to be a successful biocontrol agent for F. japonica. However, this potential has not materialised in the field where long-term establishment of A. itadori has been unsuccessful and faces the added challenge of climate change. Intraspecific variation (variation among individuals of a species) has been shown to support establishment in alien species and improve resilience to changing environmental conditions, here we propose it could improve the performance of biocontrols. To test this possibility we compared the performance and impact on F. japonica of three strains of A. itadori with different genetic backgrounds, including a newly created hybrid. We hypothesize that genetic variability would be increased in hybrids resulting in greater biocontrol effectiveness (greater impact on plant growth). We also explored the potential influence of changing climate in performance, testing all strains under two humidity conditions (with the same temperature). Contrary to our expectation, the hybrid strain had the worst performance (slowest development rate and lower survival from egg to adult emergence) under both environmental conditions. Exposure to different strains of A. itadori did not result in consistent differences in plant growth, suggesting similar biocontrol effectiveness among strains. Under the drier, more stressful, conditions plants exposed to A. itadori had fewer leaves and accumulated less above-ground biomass. Overall, our results suggest that genetic variability may not be the key to improve A. itadori biocontrol effectiveness, but that predicted climate change, which anticipates drier and hotter summers in the UK, could reduce the growth potential of F. japonica when exposed to A. itadori

The interface between Macroecology and Conservation : existing links and untapped opportunities

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