Photosynthesis and calcification in the calcifying algae Halimeda discoidea studied with microsensors

With microsensors, we measured the steady‐state microprofiles of O2, pH and Ca2+ on the topside of young segments of Halimeda discoidea, as well as the surface dynamics upon light–dark shifts. The effect of several inhibitors was studied. The steady‐state measurements showed that under high light intensity, calcium and protons were taken up, while O2 was produced. In the dark, O2 was consumed, the pH decreased to below seawater level and Ca2+ uptake was reduced to 50%. At low light intensity (12 mmol photons m‐2 s‐1), Ca2+ efflux was observed. Upon light–dark shifts, a complicated pattern of both the pH and calcium surface dynamics was observed. Illumination caused an initial pH decrease, followed by a gradual pH increase: this indicated that the surface pH of H. discoidea is determined by more than one light‐induced process. When photosynthesis was inhibited by dichlorophenyl dimethyl urea (DCMU), a strong acidification was observed upon illumination. The nature and physiological function of this putative pump is not known. The calcium dynamics followed all pH dynamics closely, both in the presence and absence of DCMU. The Ca‐channel blockers verapamil and nifedipine had no effect on the Ca2+ dynamics and steady‐state profiles. Thus, in H. discoidea, calcification is not regulated by the alga, but is a consequence of pH increase during photosynthesis. Acetazolamide had no effect on photosynthesis, whereas ethoxyzolamide inhibited photosynthesis at higher light intensities. Therefore, all carbonic anhydrase activity is intracellular. Carbonic anhydrase is required to alleviate the CO2 limitation. Calcification cannot supply sufficient protons and CO2 to sustain photosynthesis

Maximal Ergodic Inequalities for Banach Function Spaces

We analyse the Transfer Principle, which is used to generate weak type maximal inequalities for ergodic operators, and extend it to the general case of $\sigma$-compact locally compact Hausdorff groups acting measure-preservingly on $\sigma$-finite measure spaces. We show how the techniques developed here generate various weak type maximal inequalities on different Banach function spaces, and how the properties of these function spaces influence the weak type inequalities that can be obtained. Finally, we demonstrate how the techniques developed imply almost sure pointwise convergence of a wide class of ergodic averages.Comment: 46 pages. The former Lemma 4.7 and Theorem 4.8 (which had a small gap in the proof) is replaced by Theorem 4.7. This change affects the latter part of section

Population scenarios and policy implications for South Mediterranean countries, 2010-2050

Four population scenarios were derived describing changes in indicators of demographic behaviour should people come to live in different future political-economic contexts. Focus of this policy brief is on expected trends in (1) population growth at regional and national levels, (2) working age populations in view of demographic dividend potential for the economy, and (3) population of elderly persons in view of the future financial burden this group might impose on societies. Results show that different economic-political development scenarios do have large effects on population growth, at least up to 2030). This is due to the socalled population momentum effect in the relatively young age-structures of most SMCs. In the short term, up to 2030, and depending on which economic-political unfolds, SMCs expected to grow from 280 million people to a figure between 362 and 349 million people. Thus, in a period of about 20 years SMC populations are expected to grow with a figure between 69 and 83 million. In that same period, EU27 populations will grow with 21 million only from about 500 to 521 million people. Between 2030 and 2050, additional population growth is foreseen in SMCs, between 48 and 62 million people, while EU27 populations are expected to grow with only 4 million during that period. SMCs appear to vary widely regarding demographic transition profiles so that demographic dividend potentials also vary. For instance, Egypt has considerably demographic dividend potential ahead in the coming decades as working age population shares will rise from 63% (2010) to a peak level of about 68% by 2045. In Turkey though, the working age population share is already high (68%) and near the expected peak level of 69% (by 2025) after which a decline sets in. The window of opportunity -the period when working age population shares rise to peak levels and remain at a high level- is starting to close for Lebanon and Tunisia though levels will remain high up to 2035 after which a decline sets in due to ageing of these populations. Ageing implies an increase of the economic burden to economies as elderly generally do not contribute any longer to economies as they did during their working age years. Old-age dependency ratios, the share of elderly in relation to the working age population, are still low compared to EU27 ratios but will increase after 2035. Should SMCs remain politically, economically and environmentally fragile in the coming decades, these lower dependency ratios will impose a relatively higher social and financial burden to societies than the high dependency ratios in EU countries

Population scenarios 2010-2050 for MED11 countries: a MEDPRO WP3 research report

The focus of this report is on population and development scenarios of MED11 countries for the period 2010-2050. More specifically, we address (1) design aspects of the MEDPRO population and development scenarios, and projection methodology, (2) main results of population scenarios for MED11 countries, including comparison with results of the UN medium variant projection and EUROSTAT EU-27 population projection, and (3) we reflect on the implications of the scenarios for policy and planning, and elaborate on what the effect of the current dramatic political and societal events in the region might be on the results of our population scenarios. Section 2 describes the MEDPRO framework for development scenarios. Sections 3 and 4 describe how demographic behaviour might respond if people in MED11 countries would live in four different macro-economic and political contexts. Focus in section 3 is on developing story lines, i.e. qualitative population scenarios, about how demographic behaviour may change if the development context change, and we operationalize these in the form of quantitative population scenarios. In section 4 we briefly describe the population projection methodology and we present and analyse main results of the population scenarios 2010-2050 for MED11 countries. In section 5 we discuss address the implications of the population scenarios and reflect on the plausibility of the results in light of the dramatic political transitions in the region.

The impact on employer operating costs of low cost health insurance including an HIV/treatment benefit: results of a study of five employers in Namibia

This repository item contains a single issue of the Health and Development Discussion Papers, an informal working paper series that began publishing in 2002 by the Boston University Center for Global Health and Development. It is intended to help the Center and individual authors to disseminate work that is being prepared for journal publication or that is not appropriate for journal publication but might still have value to readers.OBJECTIVE: The impact of low-cost health insurance on the costs incurred by Namibian employers was measured. BACKGROUND: Namibia has a relatively recent HIV epidemic and adult HIV prevalence estimated at 15.3%. AIDS-related mortality would be rising in the absence of antiretroviral treatment. (ART). Medical schemes in Namibia now offer low-cost policies that include good coverage for treatment of AIDS, including ART. In 2006-2007, a number of large Namibian employers agreed to purchase such policies for their uninsured workers. METHODOLOGY: We compared data on worker attrition and related costs for the period before and after purchase of the low cost health insurance policy. RESULTS: Worker attrition (death and medical retirement) reported by the companies declined from a range of 1.5% to 2.0% of the work force in 2005 and 2006 to 0.7% to 1.1% in 2008. When data was pooled, attrition fell from a peak of 1.7% of the combined work force in 2005 to 0.9% in 2008. Attrition-related costs at the companies were lower in 2008 than in the peak attrition years. The downward trend in attrition appears to have begun before the date when the firms purchased the new policies. The 2008 value of the savings measured was less than the annual cost of the premiums for the new policies. DISCUSSION: Antiretroviral treatment appears to reduce workforce attrition and related costs for Namibian employers. However, we cannot say if this is a result of new low-cost insurance policies or the rapid expansion of ART in the public sector

Comparison of key unit costs and outcomes for mobile and fixed site screening/testing programs in Namibia

This repository item contains a single issue of the Health and Development Discussion Papers, an informal working paper series that began publishing in 2002 by the Boston University Center for Global Health and Development. It is intended to help the Center and individual authors to disseminate work that is being prepared for journal publication or that is not appropriate for journal publication but might still have value to readers

Putting the pieces of the puzzle together: Age and sex-specific estimates of migration amongst countries in the EU/EFTA, 2002-2007

Because of inconsistencies in reported flows and large amounts of missing data, our knowledge of international migration patterns in Europe is limited. Methods for overcoming data obstacles and harmonising international migration data, however, are improving. In this paper, we provide a methodology for integrating various pieces of incomplete information together, including a partial set of harmonised migration flows, to estimate a complete set of migration flows by origin, destination, age and sex for the 31 countries in the European Union and European Free Trade Association from 2002 to 2007. The results represent a synthetic data base that can be used to inform population projections, policy decisions and migration theory.Du fait d’incohérences dans l’enregistrement des flux migratoires et du grand nombre de données manquantes, notre connaissance des schémas de migrations internationales en Europe reste limitée. Cependant, les méthodes disponibles pour surmonter les obstacles liés aux données et pour harmoniser les données sur la migration internationale s’améliorent. Dans cet article, nous proposons une méthode pour combiner les différents éléments de ces informations incomplètes, incluant un ensemble partiel de données harmonisées sur les flux migratoires, afin d’estimer une série complète de flux migratoires par pays d’origine, pays de destination, âge et sexe pour les 31 pays de l’Union Européenne et de l’Association Européenne de Libre Echange de 2002 à 2007. Les résultats constituent une base de données synthétique pouvant servir de base pour les projections de population, les décisions politiques et les théories relatives à la migration