Response of photosynthetic organisms to global change: an approach based on marker pigments

Report for the scientific sojourn carried out at the Department of Freshwater Ecology, National Environmetal Research Institute, Denmark, from 2006 to 2008. The main objective of the project was to reconstruct photosynthetic organism community composition using pigmentbased methods and to study their response to natural (e.g. climate) or anthropogenic (e.g. eutrophication) perturbations that took place in the system over time. We performed a study in different locations and at different temporal scales. We analysed the pigment composition in a short sediment record (46 cm sediment depth) of a volcanic lake (Lake Furnas) in the Azores Archipelago (Portugal). The lake has been affected during the last century by successive fish introductions. The specific objective was to reconstruct the lake’s trophic state history and to assess the role of land-use, climate and fish introductions in structuring the lake community. Results obtained suggested that whereas trophic cascade and changes in nutrient concentrations have some clear effects on algal and microbial assemblages, interpreting the effects of changes in climate are not straightforward. This is probably related with the rather constant precipitation in the Azores Islands during the studied period. We also analysed the pigment composition in a long sediment record (1800 cm sediment depth) of Lake Aborre (Denmark) covering ca. 8kyr of lake history. The specific objective was to describe changes in lake primary production and lake trophic state over the Holocene and to determine the photosynthetic organisms involved. Results suggested that external forcing (i.e. land use changes) was responsible of erosion and nutrient run off to the lake that contributed to the reported changes in lake primary production along most of the Holocene.

Estudi de l'impacte ecotoxicològic de l'insecticida imidacloprid en diferents compartiments ambientals

En les darreres dècades la necessitat d’una major producció en l’agricultura ha implicat l’ús de productes químics per a millorar la producció. Entre aquests productes trobem els insecticides que, tot i ser específics per a determinades funcions, en molts casos acaben afectant també a altres organismes que no en són la diana. Els assajos d’ecotoxicitat són una eina clau per a determinar el grau d’afectació d’aquests insecticides. En aquest estudi es pretén determinar l’efecte de l’aplicació directa en el sòl de les dosis recomanades de l’insecticida Confidor 20SL (amb imidacloprid com a principi actiu) sobre Eisenia fetida i dels lixiviats d’aquests sòls sobre Daphnia magna i Selenastrum capricornutum simulant fenòmens d’escorrentia o lixiviació naturals. En el cas de E.fetida s’obté una LC50 de 24.71 mg/kg sòl i per la reproducció un valor de EC50 de 8.41 mg/kg sòl. S’observa allunyament en totes les dosis utilitzades i la EC50 és de 2.57 mg/kg sòl. No s’han pogut determinar efectes a nivell neurològic a partir de la determinació de l’activitat de l’ AChE. A l’exposar D.magna als lixiviats del sòl contaminat no s’han observat efectes clars ni en la mortalitat ni en la reproducció. El mateix succeeix amb S.capricornutum. Les dosis d’aplicació del pesticida Confidor, representen una amenaça per a E.fetida pel que fa a efectes subletals però no podem dir el mateix per als organismes aquàtics.

Macrofossils in Raraku Lake (Easter Island) integrated with sedimentary and geochemical records towards a palaeoecological synthesis for the last 34,000 years

Macrofossil analysis of a composite 19 m long sediment core from Rano Raraku Lake (Easter Island)was related to litho-sedimentary and geochemical features of the sediment. Strong stratigraphical patterns are shown by indirect gradient analyses of the data. The good correspondence between the stratigraphical patterns derived from macrofossil (Correspondence Analysis) and sedimentary and geochemical data (Principal Component Analysis) shows that macrofossil associations provide sound palaeolimnological information in conjunction with sedimentary data. The main taphonomic factors in fluencing the macrofossil assemblages are run-off from the catchment, the littoral plant belt, and the depositional environment within the basin. Five main stages during the last 34,000 calibrated years BP (cal yr BP) are characterised from the lithological, geochemical, and macrofossil data. From 34 to 14.6 cal kyr BP (last glacial period) the sediments were largely derived from the catchment, indicating a high energy lake environment with much erosion and run-off bringing abundant plant trichomes, lichens, and mosses into the centre of Raraku Lake.

Long-run Inflation-Unemployment Dynamics: The Spanish Phillips Curve and Economic Policy

This paper takes a new look at the long-run dynamics of inflation and unemployment in response to permanent changes in the growth rate of the money supply. We examine the Phillips curve from the perspective of what we call "frictional growth", i.e. the interaction between money growth and nominal frictions. After presenting theoretical models of this phenomenon, we construct an empirical model of the Spanish economy and, in this context, we evaluate the long-run inflation-unemployment trade for Spain and examine how recent policy changes have afected it.

The short and long-run determinants of the real exchange rate in Mexico

This paper explores the real exchange rate behavior in Mexico from 1960 until 2005. Since the empirical analysis reveals that the real exchange rate is not mean reverting, we propose that economic fundamental variables affect its evolution in the long-run. Therefore, based on equilibrium exchange rate paradigms, we propose a simple model of real exchange rate determination which includes the relative labor productivity, the real interest rates and the net foreign assets over a long period of time. Our analysis also considers the dynamic adjustment in response to shocks through impulse response functions derived from the multivariate VAR model.

Long-run selection and the work ethic

That individuals contribute in social dilemma interactions even when contributing is costly is a well-established observation in the experimental literature. Since a contributor is always strictly worse off than a non-contributor the question is raised if an intrinsic motivation to contribute can survive in an evolutionary setting. Using recent results on deterministic approximation of stochastic evolutionary dynamics we give conditions for equilibria with a positive number of contributors to be selected in the long run.

Killing by lung cancer or by diabetes? The trade-off between smoking and obesity

As the prevalence of smoking has decreased to below 20%, health practitioners interest has shifted towards theprevalence of obesity, and reducing it is one of the major health challenges in decades to come. In this paper westudy the impact that the final product of the anti-smoking campaign, that is, smokers quitting the habit, had onaverage weight in the population. To these ends, we use data from the Behavioral Risk Factors Surveillance System,a large series of independent representative cross-sectional surveys. We construct a synthetic panel that allows us tocontrol for unobserved heterogeneity and we exploit the exogenous changes in taxes and regulations to instrumentthe endogenous decision to give up the habit of smoking. Our estimates, are very close to estimates issued in the 90sby the US Department of Health, and indicate that a 10% decrease in the incidence of smoking leads to an averageweight increase of 2.2 to 3 pounds, depending on choice of specification. In addition, we find evidence that the effectovershoots in the short run, although a significant part remains even after two years. However, when we split thesample between men and women, we only find a significant effect for men. Finally, the implicit elasticity of quittingsmoking to the probability of becoming obese is calculated at 0.58. This implies that the net benefit from reducingthe incidence of smoking by 1% is positive even though the cost to society is $0.6 billions.

Available evidence and outcome of off-label use of rituximab in clinical practice

Purpose: To analyze the therapeutic indications for off-label use of rituximab, the available evidence for its use, the outcomes, and the cost. Methods: This was a retrospective analysis of patients treated with rituximab for off-label indications from January 2007 to December 2009 in two tertiary hospitals. Information on patient characteristics, medical conditions, and therapeutic responses was collected from medical records. Available evidence for the efficacy of rituximab in each condition was reviewed, and the cost of treatment was calculated. Results: A total of 101 cases of off-label rituximab use were analyzed. The median age of the patients involved was 53 [interquartile range (IQR) 37.568.0] years; 55.4 % were women. The indications for prescribing rituximab were primarily hematological diseases (46 %), systemic connective tissue disorders (27 %), and kidney diseases (20 %). Available evidence supporting rituximab treatment for these indications mainly came from individual cohort studies (53.5 % of cases) and case series (25.7 %). The short-term outcome (median 3 months, IQR 24 months) was a complete response in 38 % of cases and partial response in 32.6 %. The highest short-term responses were observed for systemic lupus erythematosus and membranous glomerulonephritis, and the lowest was for neuromyelitis optica, idiopathic thrombocytopenic purpura, and miscellaneous indications. Some response was maintained in long-term follow-up (median 23 months IQR 1230months) in 69.2%of patients showing a short-term response. Median cost per patient was 5,187.5 (IQR 5,187.57,781.3). Conclusions: In our study, off-label rituximab was mainly used for the treatment of hematological, kidney, and systemic connective tissue disorders, and the response among our patient cohort was variable depending on the specific disease. The level of evidence supporting the use of rituximab for these indications was low and the cost was very high. We conclude that more clinical trials on the off-label use of rituximab are needed, although these may be difficult to conduct in some rare diseases. Data from observational studies may provide useful information to assist prescribing in clinical practice.

Available evidence and outcome of off-label use of rituximab in clinical practice

Purpose: To analyze the therapeutic indications for off-label use of rituximab, the available evidence for its use, the outcomes, and the cost. Methods: This was a retrospective analysis of patients treated with rituximab for off-label indications from January 2007 to December 2009 in two tertiary hospitals. Information on patient characteristics, medical conditions, and therapeutic responses was collected from medical records. Available evidence for the efficacy of rituximab in each condition was reviewed, and the cost of treatment was calculated. Results: A total of 101 cases of off-label rituximab use were analyzed. The median age of the patients involved was 53 [interquartile range (IQR) 37.5-68.0] years; 55.4 % were women. The indications for prescribing rituximab were primarily hematological diseases (46 %), systemic connective tissue disorders (27 %), and kidney diseases (20 %). Available evidence supporting rituximab treatment for these indications mainly came from individual cohort studies (53.5 % of cases) and case series (25.7 %). The short-term outcome (median 3 months, IQR 2-4 months) was a complete response in 38 % of cases and partial response in 32.6 %. The highest short-term responses were observed for systemic lupus erythematosus and membranous glomerulonephritis, and the lowest was for neuromyelitis optica, idiopathic thrombocytopenic purpura, and miscellaneous indications. Some response was maintained in long-term follow-up (median 23 months IQR 12-30months) in 69.2%of patients showing a short-term response. Median cost per patient was 5,187.5 (IQR 5,187.5-7,781.3). Conclusions: In our study, off-label rituximab was mainly used for the treatment of hematological, kidney, and systemic connective tissue disorders, and the response among our patient cohort was variable depending on the specific disease. The level of evidence supporting the use of rituximab for these indications was low and the cost was very high. We conclude that more clinical trials on the off-label use of rituximab are needed, although these may be difficult to conduct in some rare diseases. Data from observational studies may provide useful information to assist prescribing in clinical practice.

A carboxylesterase, Esterase-6, modulates sensory physiological and behavioural response dynamics to pheromone in Drosophila

Background: Insects respond to the spatial and temporal dynamics of a pheromone plume, which implies not only a strong response to"odor on", but also to"odor off". This requires mechanisms geared toward a fast signal termination. Several mechanisms may contribute to signal termination, among which odorant-degrading enzymes. These enzymes putatively play a role in signal dynamics by a rapid inactivation of odorants in the vicinity of the sensory receptors, although direct in vivo experimental evidences are lacking. Here we verified the role of an extracellular carboxylesterase, esterase-6 (Est-6), in the sensory physiological and behavioral dynamics of Drosophila melanogaster response to its pheromone, cis-vaccenyl acetate (cVA). Est-6 was previously linked to post-mating effects in the reproductive system of females. As Est-6 is also known to hydrolyze cVA in vitro and is expressed in the main olfactory organ, the antenna, we tested here its role in olfaction as a putative odorant-degrading enzyme. Results: We first confirm that Est-6 is highly expressed in olfactory sensilla, including cVA-sensitive sensilla, and we show that expression is likely associated with non-neuronal cells. Our electrophysiological approaches show that the dynamics of olfactory receptor neuron (ORN) responses is strongly influenced by Est-6, as in Est-6° null mutants (lacking the Est-6 gene) cVA-sensitive ORN showed increased firing rate and prolonged activity in response to cVA. Est-6° mutant males had a lower threshold of behavioral response to cVA, as revealed by the analysis of two cVAinduced behaviors. In particular, mutant males exhibited a strong decrease of male-male courtship, in association with a delay in courtship initiation. Conclusions: Our study presents evidence that Est-6 plays a role in the physiological and behavioral dynamics of sex pheromone response in Drosophila males and supports a role of Est-6 as an odorant-degrading enzyme (ODE) in male antennae. Our results also expand the role of Est-6 in Drosophila biology, from reproduction to olfaction, and highlight the role of ODEs in insect olfaction. Keywords: carboxylesterase, esterase 6, olfaction, pheromone, signal termination