Reproducibility of aortic intima-media thickness in infants using edge-detection software and manual caliper measurements

Background: Aortic intima-media thickness measured by transabdominal ultrasound (aIMT) is an intermediate phenotype of cardiovascular risk. We aimed to (1) investigate the reproducibility of aIMT in a population-derived cohort of infants; (2) establish the distribution of aIMT in early infancy; (3) compare measurement by edge-detection software to that by manual sonographic calipers; and (4) assess the effect of individual and environmental variables on image quality. Methods. Participants were term infants recruited to a population-derived birth cohort study. Transabdominal ultrasound was performed at six weeks of age by one of two trained operators. Thirty participants had ultrasounds performed by both operators on the same day. Data were collected on environmental (infant sleeping, presence of a sibling, use of sucrose, timing during study visit) and individual (post-conception age, weight, gender) variables. Two readers assessed image quality and measured aIMT by edge-detection software and a subset by manual sonographic calipers. Measurements were repeated by the same reader and between readers to obtain intra-observer and inter-observer reliability. Results: Aortic IMT was measured successfully using edge-detection in 814 infants, and 290 of these infants also had aIMT measured using manual sonographic calipers. The intra-reader intra-class correlation (ICC) (n = 20) was 0.90 (95% CI 0.76, 0.96), mean difference 1.5 μm (95% LOA -39, 59). The between reader ICC using edge-detection (n = 20) was 0.92 (95% CI 0.82, 0.97) mean difference 2 μm (95% LOA -45.0, 49.0) and with manual caliper measurement (n = 290) the ICC was 0.84 (95% CI 0.80, 0.87) mean difference 5 μm (95% LOA -51.8, 61.8). Edge-detection measurements were greater than those from manual sonographic calipers (mean aIMT 618 μm (50) versus mean aIMT 563 μm (49) respectively; p < 0.001, mean difference 44 μm, 95% LOA -54, 142). With the exception of infant crying (p = 0.001), no associations were observed between individual and environmental variables and image quality. Conclusion: In a population-derived cohort of term infants, aIMT measurement has a high level of intra and inter-reader reproducibility. Measurement of aIMT using edge-detection software gives higher inter-reader ICC than manual sonographic calipers. Image quality is not substantially affected by individual and environmental factors. © 2014 McCloskey et al.; licensee BioMed Central Ltd

Temporal dynamics of aquatic communities and implications for pond conservation

Conservation through the protection of particular habitats is predicated on the assumption that the conservation value of those habitats is stable. We test this assumption for ponds by investigating temporal variation in macroinvertebrate and macrophyte communities over a 10-year period in northwest England. We surveyed 51 ponds in northern England in 1995/6 and again in 2006, identifying all macrophytes (167 species) and all macroinvertebrates (221 species, excluding Diptera) to species. The alpha-diversity, beta-diversity and conservation value of these ponds were compared between surveys. We find that invertebrate species richness increased from an average of 29. 5 species to 39. 8 species between surveys. Invertebrate gamma-diversity also increased between the two surveys from 181 species to 201 species. However, this increase in diversity was accompanied by a decrease in beta-diversity. Plant alpha-, beta and gamma-diversity remained approximately constant between the two periods. However, increased proportions of grass species and a complete loss of charophytes suggests that the communities are undergoing succession. Conservation value was not correlated between sampling periods in either plants or invertebrates. This was confirmed by comparing ponds that had been disturbed with those that had no history of disturbance to demonstrate that levels of correlation between surveys were approximately equal in each group of ponds. This study has three important conservation implications: (i) a pond with high diversity or high conservation value may not remain that way and so it is unwise to base pond conservation measures upon protecting currently-speciose habitats; (ii) maximising pond gamma-diversity requires a combination of late and early succession ponds, especially for invertebrates; and (iii) invertebrate and plant communities in ponds may require different management strategies if succession occurs at varying rates in the two groups

Memoria, responsabilidad, resistencia. Apuntes sobre ética y política en la ficción de José Saramago

Las tres nociones teóricas que constituyen el dispositivo conceptual de la propuesta aquí presentada, que lleva por título: Memoria, responsabilidad, resistencia (apuntes sobre ética y política en la ficción de José Saramago) y que tienen como eje articulador la marginalidad (desde que opera –benjaminianamente – sobre las relaciones de desigualdad y exclusión), orientan el trabajo heurístico con los textos escogidos como corpus y circunscriben sus alcances y limitaciones. Lo que se pretende en esta nueva etapa –entendida como continuidad de un proceso – es construir una teoría de análisis del discurso saramaguiano desde su intelección ético-política , tomando como referenciales las nociones bajtinianas de «discurso, epistemología, antagonismo, ideología, sujeto y poder». Y para ello, el «recorte» procedimental de las categorías enunciadas sirve como línea transversal de lectura que despliega las significaciones narrativas y las transforma en enunciados de valor y toma de posición. «Memoria» entendida en singular recoge las tesis benjaminianas sobre el «concepto de historia» que operan sobre ese radical campo de estudio que es el «pasado» y recuperan las voces acalladas de los «oprimidos» de la historia, postulando una lectura «a contrapelo » de la historia nacional y global. Situándose, en el caso de las referencialidades saramaguianas, en el contexto que articula la dictadura antes y después de su presencia en el escenario del siglo XX, el trabajo analítico focalizará en los modos de perduración de la memoria y la capacidad pregnante de irrumpir en el presente instaurando nuevos modos discursivos de resistencia. La noción de «responsabilidad» tiene una herencia múltiple en el equipo de investigación pero –sobre todo– conjuga con las tesis de Tzvetan Todorov sobre la ética de las víctimas, adentrándose en el estudio de la «alteridad» como presupuesto indiscutible y con el concepto de eticidad, vinculado a la teoría del reconocimiento desarrollada por Axel Honneth. Por último, la «resistencia» abre hacia una lectura política de la ficción de José Saramago que el procedimiento heurístico y hermenéutico de la investigación, a partir de los enunciados de Foucault y de Said –entre otros– pretende radicalizar. La conjunción tripartita de las nociones destacadas y su dinamicidad dialéctica aseguran la constitución de un referencial teórico que pretende instalar en el aparato crítico sobre la ficción del autor portugués, un dispositivo conceptual a partir del cual dialogar con el pensamiento y la filosofía contemporáne

Habitat filtering determines spatial variation of macroinvertebrate community traits in northern headwater streams

Although our knowledge of the spatial distribution of stream organisms has been increasing rapidly in the last decades, there is still little consensus about trait-based variability of macroinvertebrate communities within and between catchments in near-pristine systems. Our aim was to examine the taxonomic and trait based stability vs. variability of stream macroinvertebrates in three high-latitude catchments in Finland. The collected taxa were assigned to unique trait combinations (UTCs) using biological traits. We found that only a single or a highly limited number of taxa formed a single UTC, suggesting a low degree of redundancy. Our analyses revealed significant differences in the environmental conditions of the streams among the three catchments. Linear models, rarefaction curves and beta-diversity measures showed that the catchments differed in both alpha and beta diversity. Taxon- and trait-based multivariate analyses also indicated that the three catchments were significantly different in terms of macroinvertebrate communities. All these findings suggest that habitat filtering, i.e., environmental differences among catchments, determines the variability of macroinvertebrate communities, thereby contributing to the significant biological differences among the catchments. The main implications of our study is that the sensitivity of trait-based analyses to natural environmental variation should be carefully incorporated in the assessment of environmental degradation, and that further studies are needed for a deeper understanding of trait-based community patterns across near-pristine streams

Etica y política en la novela y el ensayo de José Saramago

Al plantear la dimensión ético-política de un texto se presupone un análisis axiológico de los valores que sostiene y sustrae en su emergencia discursiva, esto es la imagen de mundo, la concepción filosófica en que se sustenta y la voluntad práctica que propicia. Una lectura ético-política de un texto –en este orden– supone «usarlo» (al menos en el sentido que Humberto Eco le concede) al «autotelizarlo», es decir, transformarlo en vehículo de una reflexión colectiva. Potenciarlo en sus posibilidades y tornarlo acontecimiento de lenguaje; pragmatizarlo en su intención para leerlo documentaria y documentalmente, sin dejar de reconocerlo como ente en sí mismo. Se está haciendo referencia –claro está– a las implicancias ético-culturales y ético-políticas que los textos literarios presuponen, pero también a una dimensión productiva que opera en su enunciación, aquella que Saramago refiere cuando proclama la necesidad de una «insurrección ética» que devuelva a los seres humanos la capacidad de responsabilizarse de su lugar en el mundo. De allí el imperativo categórico que se imprime en sus textos y que al Equipo Saramaguiano de Teoría y Crítica Literarias le interesa explicitar. La lectura propuesta por el Equipo de investigación, además de explorar las potencialidades significativas de los textos, pretende contribuir a través de ellas a una segunda lectura, de orden refractaria esta última, es decir, inscripta en una dimensión situada: la perspectiva latinoamericana. No se trata de explorar el significado en sí mismo ni de ordenarlo conforme a una coordenada que le es referencialmente precisa, sino de aportar reflexiva y responsablemente a un análisis más profundo de la realidad inmediata en la que habitamos como investigadores. Se busca –en suma– potenciar los procedimientos heurísticos al máximo pero hacerlos conscientes de una mirada propia, al costurarlos con «nuestro» aquí y ahora de universitarios latinoamericanos.Fil: Koleff, Miguel Alberto. Universidad Católica de Córdoba. Facultad de Filosofía y Humanidades; Argentin

How should beta-diversity inform biodiversity conservation?

To design robust protected area networks, accurately measure species losses, or understand the processes that maintain species diversity, conservation science must consider the organization of biodiversity in space. Central is beta-diversity - the component of regional diversity that accumulates from compositional differences between local species assemblages. We review how beta-diversity is impacted by human activities, including farming, selective logging, urbanization, species invasions, overhunting, and climate change. Beta-diversity increases, decreases, or remains unchanged by these impacts, depending on the balance of processes that cause species composition to become more different (biotic heterogenization) or more similar (biotic homogenization) between sites. While maintaining high beta-diversity is not always a desirable conservation outcome, understanding beta-diversity is essential for protecting regional diversity and can directly assist conservation planning. Beta-diversity reveals the spatial scaling of diversity loss.Beta-diversity illuminates mechanisms of regional diversity maintenance.Human activities cause beta-diversity to increase, decrease, or remain unchanged.Conservation significance of beta-diversity shift depends on local diversity dynamics

Memoria, responsabilidad, resistencia. Apuntes sobre ética y política en la ficción de José Saramago

Las tres nociones teóricas que constituyen el dispositivo conceptual de la propuesta aquí presentada, que lleva por título: Memoria, responsabilidad, resistencia (apuntes sobre ética y política en la ficción de José Saramago) y que tienen como eje articulador la marginalidad (desde que opera –benjaminianamente – sobre las relaciones de desigualdad y exclusión), orientan el trabajo heurístico con los textos escogidos como corpus y circunscriben sus alcances y limitaciones. Lo que se pretende en esta nueva etapa –entendida como continuidad de un proceso – es construir una teoría de análisis del discurso saramaguiano desde su intelección ético-política , tomando como referenciales las nociones bajtinianas de «discurso, epistemología, antagonismo, ideología, sujeto y poder». Y para ello, el «recorte» procedimental de las categorías enunciadas sirve como línea transversal de lectura que despliega las significaciones narrativas y las transforma en enunciados de valor y toma de posición. «Memoria» entendida en singular recoge las tesis benjaminianas sobre el «concepto de historia» que operan sobre ese radical campo de estudio que es el «pasado» y recuperan las voces acalladas de los «oprimidos» de la historia, postulando una lectura «a contrapelo » de la historia nacional y global. Situándose, en el caso de las referencialidades saramaguianas, en el contexto que articula la dictadura antes y después de su presencia en el escenario del siglo XX, el trabajo analítico focalizará en los modos de perduración de la memoria y la capacidad pregnante de irrumpir en el presente instaurando nuevos modos discursivos de resistencia. La noción de «responsabilidad» tiene una herencia múltiple en el equipo de investigación pero –sobre todo– conjuga con las tesis de Tzvetan Todorov sobre la ética de las víctimas, adentrándose en el estudio de la «alteridad» como presupuesto indiscutible y con el concepto de eticidad, vinculado a la teoría del reconocimiento desarrollada por Axel Honneth. Por último, la «resistencia» abre hacia una lectura política de la ficción de José Saramago que el procedimiento heurístico y hermenéutico de la investigación, a partir de los enunciados de Foucault y de Said –entre otros– pretende radicalizar. La conjunción tripartita de las nociones destacadas y su dinamicidad dialéctica aseguran la constitución de un referencial teórico que pretende instalar en el aparato crítico sobre la ficción del autor portugués, un dispositivo conceptual a partir del cual dialogar con el pensamiento y la filosofía contemporáneaFil: Koleff, Miguel Alberto. Universidad Católica de Córdoba. Facultad de Filosofía y Humanidades; Argentin

Species Richness and Range Size of the Terrestrial Mammals of the World: Biological Signal within Mathematical Constraints

We explore global spatial diversity patterns for terrestrial mammals using as a tool range-diversity plots. These plots display simultaneously information about the number of species in localities and their spatial covariance in composition. These are highly informative, as we show by linking range-diversity plots with maps and by highlighting the correspondences between well defined regions of the plots with geographical regions or with taxonomic groups. Range-diversity plots are mathematically constrained by the lines of maximum and minimum mean covariance in species composition. We show how regions in the range-diversity plot corresponding to the line of maximum covariance correspond to large continental masses, and regions near the lower limit of the range-diversity plot correspond to archipelagos and mountain ranges. We show how curves of constant covariance correspond to nested faunas. Finally, we show that the observed distribution of the covariance range has significantly longer tails than random, with clear geographic correspondences. At the scale of our data we found that range-diversity plots reveal biodiversity patterns that cannot be replicated by null models, and correspond to conspicuous terrain features and taxonomic groupings

Inferring Ecological Processes from Taxonomic, Phylogenetic and Functional Trait β-Diversity

Understanding the influences of dispersal limitation and environmental filtering on the structure of ecological communities is a major challenge in ecology. Insight may be gained by combining phylogenetic, functional and taxonomic data to characterize spatial turnover in community structure (β-diversity). We develop a framework that allows rigorous inference of the strengths of dispersal limitation and environmental filtering by combining these three types of β-diversity. Our framework provides model-generated expectations for patterns of taxonomic, phylogenetic and functional β-diversity across biologically relevant combinations of dispersal limitation and environmental filtering. After developing the framework we compared the model-generated expectations to the commonly used “intuitive” expectation that the variance explained by the environment or by space will, respectively, increase monotonically with the strength of environmental filtering or dispersal limitation. The model-generated expectations strongly departed from these intuitive expectations: the variance explained by the environment or by space was often a unimodal function of the strength of environmental filtering or dispersal limitation, respectively. Therefore, although it is commonly done in the literature, one cannot assume that the strength of an underlying process is a monotonic function of explained variance. To infer the strength of underlying processes, one must instead compare explained variances to model-generated expectations. Our framework provides these expectations. We show that by combining the three types of β-diversity with model-generated expectations our framework is able to provide rigorous inferences of the relative and absolute strengths of dispersal limitation and environmental filtering. Phylogenetic, functional and taxonomic β-diversity can therefore be used simultaneously to infer processes by comparing their empirical patterns to the expectations generated by frameworks similar to the one developed here

Can additive beta-diversity be reliably partitioned into nestedness and turnover components?

Aims: Quantifying β‐diversity (differences in the composition of communities) is central to many ecological studies. There are many β‐diversity metrics, falling mostly into two approaches: variance‐based (e.g., the Sørensen index), or diversity partitioning (e.g., additive β‐diversity). The former cannot be used when species–sites matrices are unavailable (which is often the case in island biogeography in particular) and only species richness data are provided. Recently, efforts have been made to partition additive β‐diversity, a metric calculated using only α‐diversity and γ‐diversity, into nestedness and turnover components (termed here “richness‐only β‐diversity partitioning”). We set out to test whether this form of β‐diversity partitioning generates interpretable results, comparable with metrics based on species incidence β‐diversity partitioning. Location: Global. Time period: Present day. Major taxa studied: Multiple taxa. Methods: We first provide a brief review of β‐diversity partitioning methods, with a particular focus on the development of richness‐only β‐diversity partitioning. Second, we use 254 empirical incidence matrices (provided with the paper) sourced from the literature to measure turnover and nestedness using incidence β‐diversity partitioning, comparing the resulting values with those calculated using richness‐only β‐diversity. Results: We provide an account of the emergence of β‐diversity partitioning, with particular reference to the analysis of richness‐only datasets, and to the definition and usage of the relevant metrics. Analytically, we report weak correlations between turnover and nestedness calculated using the two different approaches. We show that this is because identical values of α‐diversity and γ‐diversity can correspond to incidence matrices with a range of different structures. Main conclusions: Our results demonstrate that the use of richness‐only β‐diversity partitioning to measure turnover and nestedness is problematic and can produce patterns unrelated to conventional measures of turnover and nestedness. We therefore recommend that more accurate definitions are adopted for these terms in future studies.</br