4,750 research outputs found

    A global assessment of the impact of climate change on water scarcity

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    This paper presents a global scale assessment of the impact of climate change on water scarcity. Patterns of climate change from 21 Global Climate Models (GCMs) under four SRES scenarios are applied to a global hydrological model to estimate water resources across 1339 watersheds. The Water Crowding Index (WCI) and the Water Stress Index (WSI) are used to calculate exposure to increases and decreases in global water scarcity due to climate change. 1.6 (WCI) and 2.4 (WSI) billion people are estimated to be currently living within watersheds exposed to water scarcity. Using the WCI, by 2050 under the A1B scenario, 0.5 to 3.1 billion people are exposed to an increase in water scarcity due to climate change (range across 21 GCMs). This represents a higher upper-estimate than previous assessments because scenarios are constructed from a wider range of GCMs. A substantial proportion of the uncertainty in the global-scale effect of climate change on water scarcity is due to uncertainty in the estimates for South Asia and East Asia. Sensitivity to the WCI and WSI thresholds that define water scarcity can be comparable to the sensitivity to climate change pattern. More of the world will see an increase in exposure to water scarcity than a decrease due to climate change but this is not consistent across all climate change patterns. Additionally, investigation of the effects of a set of prescribed global mean temperature change scenarios show rapid increases in water scarcity due to climate change across many regions of the globe, up to 2°C, followed by stabilisation to 4°C

    Racial disparity in long-term mortality rate after hospitalization for myocardial infarction: the Atherosclerosis Risk in Communities study

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    BACKGROUND: The underlying reasons why African American patients have a significantly higher mortality rate than European American patients after a myocardial infarction (MI) remain unclear. This study examined the racial disparity in mortality rates after MI and possible explanatory factors. METHODS: A prospective analysis was conducted within the Atherosclerosis Risk in Communities (ARIC) study, a community-based study of 15,792 middle-aged adults. From 1987 to 1998, 642 patients (471 European American and 171 African American) hospitalized for MI without prior history of MI were identified. Of these 642 patients, 129 (82 European American and 47 African American) died during follow-up. RESULTS: Cox proportional hazard models were used to analyze the racial difference in mortality rate after MI. After adjusting for age and sex, the relative hazard (RH) comparing African American patients to European American patients was 1.80 (95% CI, 1.24-2.61). The RH decreased after adjusting for vascular risk factors (1.29; 95% CI, 0.83-2.00), socioeconomic position (1.31; 95% CI, 0.83-2.09), severity of MI (1.60; 95% CI, 1.05-2.45), and treatment (1.36; 95% CI, 0.92-2.00). In the final model, which included all factors aforementioned, the RH for race was 1.00 (95% CI, 0.56-1.77). CONCLUSIONS: Our findings suggested that vascular risk factors, socioeconomic position, and treatment play major roles in the racial disparity in mortality rate after MI.http://deepblue.lib.umich.edu/bitstream/2027.42/78990/1/DingDiezRoux2003_AmHeartJ.pd

    Bryozoans are Major Modern Builders of South Atlantic Oddly Shaped Reefs

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    Supplementary information accompanies this paper at https://doi.org/10.1038/s41598-018-27961-6.In major modern reef regions, either in the Indo-Pacific or the Caribbean, scleractinian corals are described as the main reef framework builders, often associated with crustose coralline algae. We used underwater cores to investigate Late Holocene reef growth and characterise the main framework builders in the Abrolhos Shelf, the largest and richest modern tropical reef complex in the South Western Atlantic, a scientifically underexplored reef province. Rather than a typical coralgal reef, our results show a complex framework building system dominated by bryozoans. Bryozoans were major components in all cores and age intervals (2,000 yrs BP), accounting for up to 44% of the reef framework, while crustose coralline algae and coral accounted for less than 28 and 23%, respectively. Reef accretion rates varied from 2.7 to 0.9 mm yr−1, which are similar to typical coralgal reefs. Bryozoan functional groups encompassed 20 taxa and Celleporaria atlantica (Busk, 1884) dominated the framework at all cores. While the prevalent mesotrophic conditions may have driven suspensionfeeders’ dominance over photoautotrophs and mixotrophs, we propose that a combination of historical factors with the low storm-disturbance regime of the tropical South Atlantic also contributed to the region’s low diversity, and underlies the unique mushroom shape of the Abrolhos pinnacles.We thank CNPq/FAPES-Sisbiota/PELD, CAPES/IODP, CAPES/Ciências do Mar, and ANP/Brasoil for long term project funding. We also thank ICMBio for research permits and field logistic support, and Conservation International for providing and authorizing the use of the IKONOS image. JMW and JCB are International Visiting Researcher at UFES and JBRJ, supported by the Science Without Borders program. Zá Cajueiro provided invaluable field support and Ronaldo Francini, Carlos Janovitch and Lucio Engler helped in the drilling operations. This is a contribution from the Rede Abrolhos (abrolhos.org)

    Interactions and potential implications of Plasmodium falciparum-hookworm coinfection in different age groups in south-central Côte d'Ivoire

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    BACKGROUND: Given the widespread distribution of Plasmodium and helminth infections, and similarities of ecological requirements for disease transmission, coinfection is a common phenomenon in sub-Saharan Africa and elsewhere in the tropics. Interactions of Plasmodium falciparum and soil-transmitted helminths, including immunological responses and clinical outcomes of the host, need further scientific inquiry. Understanding the complex interactions between these parasitic infections is of public health relevance considering that control measures targeting malaria and helminthiases are going to scale.METHODOLOGY: A cross-sectional survey was carried out in April 2010 in infants, young school-aged children, and young non-pregnant women in south-central Côte d'Ivoire. Stool, urine, and blood samples were collected and subjected to standardized, quality-controlled methods. Soil-transmitted helminth infections were identified and quantified in stool. Finger-prick blood samples were used to determine Plasmodium spp. infection, parasitemia, and hemoglobin concentrations. Iron, vitamin A, riboflavin, and inflammation status were measured in venous blood samples.PRINCIPAL FINDINGS: Multivariate regression analysis revealed specific association between infection and demographic, socioeconomic, host inflammatory and nutritional factors. Non-pregnant women infected with P. falciparum had significantly lower odds of hookworm infection, whilst a significant positive association was found between both parasitic infections in 6- to 8-year-old children. Coinfected children had lower odds of anemia and iron deficiency than their counterparts infected with P. falciparum alone.CONCLUSIONS/SIGNIFICANCE: Our findings suggest that interaction between P. falciparum and light-intensity hookworm infections vary with age and, in school-aged children, may benefit the host through preventing iron deficiency anemia. This observation warrants additional investigation to elucidate the mechanisms and consequences of coinfections, as this information could have important implications when implementing integrated control measures against malaria and helminthiases

    Clinical trial of laronidase in Hurler syndrome after hematopoietic cell transplantation.

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    BackgroundMucopolysaccharidosis I (MPS IH) is a lysosomal storage disease treated with hematopoietic cell transplantation (HCT) because it stabilizes cognitive deterioration, but is insufficient to alleviate all somatic manifestations. Intravenous laronidase improves somatic burden in attenuated MPS I. It is unknown whether laronidase can improve somatic disease following HCT in MPS IH. The objective of this study was to evaluate the effects of laronidase on somatic outcomes of patients with MPS IH previously treated with HCT.MethodsThis 2-year open-label pilot study of laronidase included ten patients (age 5-13 years) who were at least 2 years post-HCT and donor engrafted. Outcomes were assessed semi-annually and compared to historic controls.ResultsThe two youngest participants had a statistically significant improvement in growth compared to controls. Development of persistent high-titer anti-drug antibodies (ADA) was associated with poorer 6-min walk test (6MWT) performance; when patients with high ADA titers were excluded, there was a significant improvement in the 6MWT in the remaining seven patients.ConclusionsLaronidase seemed to improve growth in participants <8 years old, and 6MWT performance in participants without ADA. Given the small number of patients treated in this pilot study, additional study is needed before definitive conclusions can be made

    Honey bee foraging distance depends on month and forage type

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    To investigate the distances at which honey bee foragers collect nectar and pollen, we analysed 5,484 decoded waggle dances made to natural forage sites to determine monthly foraging distance for each forage type. Firstly, we found significantly fewer overall dances made for pollen (16.8 %) than for non-pollen, presumably nectar (83.2 %; P < 2.2 × 10−23). When we analysed distance against month and forage type, there was a significant interaction between the two factors, which demonstrates that in some months, one forage type is collected at farther distances, but this would reverse in other months. Overall, these data suggest that distance, as a proxy for forage availability, is not significantly and consistently driven by need for one type of forage over the other

    Simultaneous quantification of 12 different nucleotides and nucleosides released from renal epithelium and in human urine samples using ion-pair reversed-phase HPLC

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    Nucleotides and nucleosides are not only involved in cellular metabolism but also act extracellularly via P1 and P2 receptors, to elicit a wide variety of physiological and pathophysiological responses through paracrine and autocrine signalling pathways. For the first time, we have used an ion-pair reversed-phase high-performance liquid chromatography ultraviolet (UV)-coupled method to rapidly and simultaneously quantify 12 different nucleotides and nucleosides (adenosine triphosphate, adenosine diphosphate, adenosine monophosphate, adenosine, uridine triphosphate, uridine diphosphate, uridine monophosphate, uridine, guanosine triphosphate, guanosine diphosphate, guanosine monophosphate, guanosine): (1) released from a mouse renal cell line (M1 cortical collecting duct) and (2) in human biological samples (i.e., urine). To facilitate analysis of urine samples, a solid-phase extraction step was incorporated (overall recovery rate ? 98 %). All samples were analyzed following injection (100 ?l) into a Synergi Polar-RP 80 Å (250 × 4.6 mm) reversed-phase column with a particle size of 10 ?m, protected with a guard column. A gradient elution profile was run with a mobile phase (phosphate buffer plus ion-pairing agent tetrabutylammonium hydrogen sulfate; pH 6) in 2-30 % acetonitrile (v/v) for 35 min (including equilibration time) at 1 ml min(-1) flow rate. Eluted compounds were detected by UV absorbance at 254 nm and quantified using standard curves for nucleotide and nucleoside mixtures of known concentration. Following validation (specificity, linearity, limits of detection and quantitation, system precision, accuracy, and intermediate precision parameters), this protocol was successfully and reproducibly used to quantify picomolar to nanomolar concentrations of nucleosides and nucleotides in isotonic and hypotonic cell buffers that transiently bathed M1 cells, and urine samples from normal subjects and overactive bladder patients

    Th2 Cell-Intrinsic Hypo-Responsiveness Determines Susceptibility to Helminth Infection

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    The suppression of protective Type 2 immunity is a principal factor driving the chronicity of helminth infections, and has been attributed to a range of Th2 cell-extrinsic immune-regulators. However, the intrinsic fate of parasite-specific Th2 cells within a chronic immune down-regulatory environment, and the resultant impact such fate changes may have on host resistance is unknown. We used IL-4gfp reporter mice to demonstrate that during chronic helminth infection with the filarial nematode Litomosoides sigmodontis, CD4(+) Th2 cells are conditioned towards an intrinsically hypo-responsive phenotype, characterised by a loss of functional ability to proliferate and produce the cytokines IL-4, IL-5 and IL-2. Th2 cell hypo-responsiveness was a key element determining susceptibility to L. sigmodontis infection, and could be reversed in vivo by blockade of PD-1 resulting in long-term recovery of Th2 cell functional quality and enhanced resistance. Contrasting with T cell dysfunction in Type 1 settings, the control of Th2 cell hypo-responsiveness by PD-1 was mediated through PD-L2, and not PD-L1. Thus, intrinsic changes in Th2 cell quality leading to a functionally hypo-responsive phenotype play a key role in determining susceptibility to filarial infection, and the therapeutic manipulation of Th2 cell-intrinsic quality provides a potential avenue for promoting resistance to helminths
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