Fatty acids from the cyanobacterium Microcystis aeruginosa with potent inhibitory effects on fish gill Na+/K+-ATPase activity

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Acumulación de Cu y Zn por célular microalgales marinas de Nannochloropsis gaditana (Eustigmatophyceae) inmovilizadas en alginato de calcio

13 páginas, 5 figuras, 2 tablas.[EN] Different experiments about the accumulation capacity for copper and zinc were carried out on the marine microalgae Nannochloropsis gaditana Lubián (Eustigmatophyceae). A 24-hour study of the evolution of accumulated metal in the beads revealed two possible accumulation phases. Accumulation differences between free and immobilized microalgal cells were investigated finding no differences for copper, and little differences for zinc. Free cells accumulated practically 100% Cu or Zn in the media under experimental conditions. Experiments in order to compare the accumulation capacity of living vs. dead cells were designed too, obtaining the largest accumulation levels for both metals in the beads containing immobilized living microalgae. In experiments carried out in continuous-flow reactors, beads with entrapped cells showed to be more efficient removing Cu and Zn than beads without cells. In all the experiments, the calcium alginate beads showed strong affinity for Cu. Similar results were obtained when accumulation by packed beads in columns was tested, but efficacy was higher if this design was used (beads with cells retain 80% of Cu introduced in the column).[ES] Se han realizado distintos experimentos sobre la capacidad de acumulación de cobre y zinc por parte de la microalga marina Nannochloropsis gaditana Lubián (Eustigmatophyceae). Un estudio de la evolución del metal acumulado durante 24 horas reveló la existencia de dos posibles fases de acumulación. Se investigaron las diferentes capacidades de acumulación de células microalgales libres e inmovilizadas, no encontrándose diferencias para el cobre y pequeñas diferencias para el zinc. Las células libres acumularon prácticamente el 100% del Cu o Zn presentes en el medio, en las condiciones experimentales. Se desarrollaron experimentos encaminados a determinar la capacidad de acumulación de estos metales por parte de algas inmovilizadas vivas frente a la de algas inmovilizadas muertas, encontrándose los niveles acumulativos más altos para ambos metales en las gotas de alginato que contenían algas vivas. En experimentos realizados en reactores de flujo continuo, las gotas de alginato con células inmovilizadas en su interior demostraron ser más eficientes en cuanto a la retirada de Cu y Zn del medio que las gotas sin algas. En todos los experimentos realizados se observa una fuerte afinidad del Cu por el alginato de calcio. Se obtuvieron resultados similares cuando se ensayó la acumulación de metales en gotas de alginato dispuestas en columnas llenas, aunque la eficacia fue mayor cuando se usó este último diseño (las gotas de alginato con células retuvieron el 80% del Cu introducido en la columna).Peer reviewe

The effect of alterations in activity and body temperature on the pulmonary surfactant system in the lesser long-eared bat Nyctophilus geoffroyi

Pulmonary surfactant is a mixture of phospholipids, neutral lipids and proteins that controls the surface tension of the fluid lining the lung. It is critical for lung stability and function. The amount and composition of surfactant are influenced by physiological variables such as metabolic rate, body temperature and ventilation. We investigated the plasticity of the pulmonary surfactant system in the microchiropteran bat Nyctophilus geoffroyi throughout a natural 24 h cycle. Bats were housed at 24 degrees C on a fixed (8 h:16 h) light:dark photoperiod. At 4 h intervals throughout the 24 h period, bats were lavaged and the surfactant analysed for absolute and relative amounts of total phospholipid (PL), disaturated phospholipid (DSP) and cholesterol (Chol). N. geoffroyi experienced two peaks of activity, at 18:00 h and 06:00 h. The amount of surfactant increased 1.5-fold upon arousal from torpor. The proportion of DSP to PL in the surfactant remained constant. Similarly, the Chol/PL and Chol/DSP ratios remained relatively constant. Surfactant cholesterol content did not increase during torpor in N. geoffroyi. Cholesterol does not appear to control surfactant fluidity during torpor in these bats, but instead the cholesterol content exactly mirrored the diurnal changes in body temperature.Nicola C. Slocombe, Jonathan R. Codd, Philip G. Wood, Sandra Orgeig and Christopher B. Daniel

End-users productivity in model-based spreadsheets: an empirical study

Lecture Notes in Computer Science Volume 6654, 2011Spreadsheets are widely used and studies show that most of the existing ones contain non-trivial errors. To improve end-users productivity, recent research proposes the use of a model-driven engineering approach to spreadsheets. In this paper we conduct the first empirical study to assess the effectiveness and efficiency of this approach. A set of spreadsheet end users worked with two different model-based spreadsheets. We present and analyze here the results achieved.(undefined

Automaton Meets Query Algebra: Towards a Unified Model for XQuery Evaluation over XML Data Streams

Abstract. In this work, we address the efficient evaluation of XQuery expressions over continuous XML data streams, which is essential for a broad range of applications including monitoring systems and infor-mation dissemination systems. While previous work has shown that au-tomata theory is suited for on-the-fly pattern retrieval over XML data streams, we find that automata-based approaches suffer from being not as flexibly optimizable as algebraic query systems. In fact, they enforce a rigid data-driven paradigm of execution. We thus now propose a unified query model to augment automata-style processing with algebra-based query optimization techniques. The proposed model has been success-fully applied in the Raindrop stream processing system. Our experimen-tal study confirms considerable performance gains with both established optimization techniques and our novel query rewrite rules.

Models and metaphors: complexity theory and through-life management in the built environment

Complexity thinking may have both modelling and metaphorical applications in the through-life management of the built environment. These two distinct approaches are examined and compared. In the first instance, some of the sources of complexity in the design, construction and maintenance of the built environment are identified. The metaphorical use of complexity in management thinking and its application in the built environment are briefly examined. This is followed by an exploration of modelling techniques relevant to built environment concerns. Non-linear and complex mathematical techniques such as fuzzy logic, cellular automata and attractors, may be applicable to their analysis. Existing software tools are identified and examples of successful built environment applications of complexity modelling are given. Some issues that arise include the definition of phenomena in a mathematically usable way, the functionality of available software and the possibility of going beyond representational modelling. Further questions arising from the application of complexity thinking are discussed, including the possibilities for confusion that arise from the use of metaphor. The metaphor of a 'commentary machine' is suggested as a possible way forward and it is suggested that an appropriate linguistic analysis can in certain situations reduce perceived complexity

Recognising Desire: A psychosocial approach to understanding education policy implementation and effect

It is argued that in order to understand the ways in which teachers experience their work - including the idiosyncratic ways in which they respond to and implement mandated education policy - it is necessary to take account both of sociological and of psychological issues. The paper draws on original research with practising and beginning teachers, and on theories of social and psychic induction, to illustrate the potential benefits of this bipartisan approach for both teachers and researchers. Recognising the significance of (but somewhat arbitrary distinction between) structure and agency in teachers’ practical and ideological positionings, it is suggested that teachers’ responses to local and central policy changes are governed by a mix of pragmatism, social determinism and often hidden desires. It is the often underacknowledged strength of desire that may tip teachers into accepting and implementing policies with which they are not ideologically comfortable

Case study on the efficacy of a lanthanum-enriched clay (Phoslock®) in controlling eutrophication in Lake Het Groene Eiland (The Netherlands)

Lake Het Groene Eiland was created in the beginning of 2008 by construction of dikes for isolating it from the surrounding 220-ha water body. This so-called claustrum of 5 ha was treated using lanthanum-modified clay (Phoslock®) to control eutrophication and mitigate cyanobacterial nuisance. Cyanobacteria chlorophyll-a were significantly lower in the claustrum than those in the reference water body, where a massive bloom developed in summer, 2008. However, PO4-P and TP did not statistically differ in these two waters. TN and NO3-N were significantly lower in the claustrum, where dense submerged macrophytes beds developed. Lanthanum concentrations were elevated after the applications of the modified clay in the claustrum, but filterable lanthanum dropped rapidly below the Dutch standard of 10.1 μg l−1. During winter, dozens of Canada geese resided at the claustrum. Geese droppings contained an average of 2 mg PO4-P g−1 dry weight and 12 mg NH3-N g−1 dry weight and might present a growing source of nutrients to the water. Constructing the claustrum enabled unrestricted bathing in subsequent three summers, as no swimming bans had to be issued due to cyanobacteria blooms. However, the role of the modified clay in this positive outcome remains unclear, and longevity of the measures questionable.

The bridge between social identity and community capital on the path to recovery and desistance

It has long been recognised that changes in social networks (and the underpinning changes in personal and social identity) are strong predictors of both desistance from crime and recovery from substance use. Building on existing work attempting to measure and shift social networks and transitions to prosocial groups, the current study provides pilot data from prisoners and family members about a visualisation technique widely used in specialist addiction treatment (node-link mapping) to map opportunities for linkage to prosocial groups and networks. The data presented in the paper are from a small-scale feasibility pilot. This suggests both bonding and bridging capital in prisoner populations due for release and the diversity of community capital opportunities that exists in this population. The implications of this work are significant for substance users and offenders pending return to the community, and has implications around resettlement and reintegration support for probation staff in prisons and in the community. The paper emphasises the importance of mapping connectedness as a key component of planning for reintegration back into the community for those working with offenders who are aspiring to achieve desistance and recovery

‘It was just like we were a family again’: play as a means to maintain family ties for children visiting an imprisoned parent

Children can find the process of visiting a prison traumatic and as a result of parental incarceration may experience a range of adverse outcomes. When children stay in contact with their imprisoned parent through prison visiting, however, this seems to be a protective factor. This paper reports on a play visits service based at Her Majesty's Prison Leeds, UK. The service provides supervised play work provision for children visiting their father. Data were derived from prisoners and prisoners' families and were triangulated as a means of achieving a level of validity. The findings reveal that play visits do produce positive outcomes for children and play visits are effective in maintaining and strengthening family ties. These effects may be stronger when compared to standard prison visits, but further research is needed to confirm this