420 research outputs found

    Does context matter for the relationship between deprivation and all-cause mortality? The West vs. the rest of Scotland

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    abstract: Background A growing body of research emphasizes the importance of contextual factors on health outcomes. Using postcode sector data for Scotland (UK), this study tests the hypothesis of spatial heterogeneity in the relationship between area-level deprivation and mortality to determine if contextual differences in the West vs. the rest of Scotland influence this relationship. Research into health inequalities frequently fails to recognise spatial heterogeneity in the deprivation-health relationship, assuming that global relationships apply uniformly across geographical areas. In this study, exploratory spatial data analysis methods are used to assess local patterns in deprivation and mortality. Spatial regression models are then implemented to examine the relationship between deprivation and mortality more formally. Results The initial exploratory spatial data analysis reveals concentrations of high standardized mortality ratios (SMR) and deprivation (hotspots) in the West of Scotland and concentrations of low values (coldspots) for both variables in the rest of the country. The main spatial regression result is that deprivation is the only variable that is highly significantly correlated with all-cause mortality in all models. However, in contrast to the expected spatial heterogeneity in the deprivation-mortality relationship, this relation does not vary between regions in any of the models. This result is robust to a number of specifications, including weighting for population size, controlling for spatial autocorrelation and heteroskedasticity, assuming a non-linear relationship between mortality and socio-economic deprivation, separating the dependent variable into male and female SMRs, and distinguishing between West, North and Southeast regions. The rejection of the hypothesis of spatial heterogeneity in the relationship between socio-economic deprivation and mortality complements prior research on the stability of the deprivation-mortality relationship over time. Conclusions The homogeneity we found in the deprivation-mortality relationship across the regions of Scotland and the absence of a contextualized effect of region highlights the importance of taking a broader strategic policy that can combat the toxic impacts of socio-economic deprivation on health. Focusing on a few specific places (e.g. 15% of the poorest areas) to concentrate resources might be a good start but the impact of socio-economic deprivation on mortality is not restricted to a few places. A comprehensive strategy that can be sustained over time might be needed to interrupt the linkages between poverty and mortality.The electronic version of this article is the complete one and can be found online at: https://ij-healthgeographics.biomedcentral.com/articles/10.1186/1476-072X-10-3

    High-Level Expression of Various Apolipoprotein (a) Isoforms by "Transferrinfection". The Role of Kringle IV Sequences in the Extracellular Association with Low-Density Lipoprotein

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    Characterization of the assembly of lipoprotein(a) [Lp(a)] is of fundamental importance to understanding the biosynthesis and metabolism of this atherogenic lipoprotein. Since no established cell lines exist that express Lp(a) or apolipoprotein(a) [apo(a)], a "transferrinfection" system for apo(a) was developed utilizing adenovirus receptor- and transferrin receptor-mediated DNA uptake into cells. Using this method, different apo(a) cDNA constructions of variable length, due to the presence of 3, 5, 7, 9, 15, or 18 internal kringle IV sequences, were expressed in cos-7 cells or CHO cells. All constructions contained kringle IV-36, which includes the only unpaired cysteine residue (Cys-4057) in apo(a). r-Apo(a) was synthesized as a precursor and secreted as mature apolipoprotein into the medium. When medium containing r-apo(a) with 9, 15, or 18 kringle IV repeats was mixed with normal human plasma LDL, stable complexes formed that had a bouyant density typical of Lp(a). Association was substantially decreased if Cys-4057 on r-apo(a) was replaced by Arg by site-directed mutagenesis or if Cys-4057 was chemically modified. Lack of association was also observed with r-apo(a) containing only 3, 5, or 7 kringle IV repeats without "unique kringle IV sequences", although Cys-4057 was present in all of these constructions. Synthesis and secretion of r-apo(a) was not dependent on its sialic acid content. r-Apo(a) was expressed even more efficiently in sialylation-defective CHO cells than in wild-type CHO cells. In transfected CHO cells defective in the addition of N-acetylglucosamine, apo(a) secretion was found to be decreased by 50%. Extracellular association with LDL was not affected by the carbohydrate moiety of r-apo(a), indicating a protein-protein interaction between r-apo(a) and apoB. These results show that, besides kringle IV-36, other kringle IV sequences are necessary for the extracellular association of r-apo(a) with LDL. Changes in the carbohydrate moiety of apo(a), however, do not affect complex formation

    On mesogranulation, network formation and supergranulation

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    We present arguments which show that in all likelihood mesogranulation is not a true scale of solar convection but the combination of the effects of both highly energetic granules, which give birth to strong positive divergences (SPDs) among which we find exploders, and averaging effects of data processing. The important role played by SPDs in horizontal velocity fields appears in the spectra of these fields where the scale ∌\sim4 Mm is most energetic; we illustrate the effect of averaging with a one-dimensional toy model which shows how two independent non-moving (but evolving) structures can be transformed into a single moving structure when time and space resolution are degraded. The role of SPDs in the formation of the photospheric network is shown by computing the advection of floating corks by the granular flow. The coincidence of the network bright points distribution and that of the corks is remarkable. We conclude with the possibility that supergranulation is not a proper scale of convection but the result of a large-scale instability of the granular flow, which manifests itself through a correlation of the flows generated by SPDs.Comment: 10 pages, 11 figures, to appear in Astronomy and Astrophysic

    Lipoprotein(a) is associated differentially with carotid stenosis, occlusion, and total plaque area

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    Background - Lipoprotein(a) [Lp(a)] is a putative risk factor for myocardial infarction and stroke and is related to thrombosis and impaired fibrinolysis. We studied relationships of Lp(a) with carotid stenosis, occlusion, and total plaque area, distinct phenotypes of atherosclerosis that may be differentially affected by cardiovascular risk factors. Methods and Results - Multivariable linear regression analysis was used to study relationships of Lp(a) to phenotypes of carotid atherosclerosis among 876 consecutive patients from an atherosclerosis prevention clinic with complete data for all variables used in the model. Occlusion of an internal carotid artery was present in 22 (2.5%) patients (one with bilateral occlusions). Risk factors predicted carotid plaque area, stenosis, and occlusion differently. Lp(a) was a significant independent predictor of baseline stenosis (P\u3c0.0001) but not of plaque area (P=0.13); in logistic regression, Lp(a) significantly predicted occlusion (P=0.001). Patients with occlusion had significantly higher levels of Lp(a): 0.27±0.25 g/L versus 0.17±0.18 g/L without occlusion; P=0.007. Conclusion - Lp(a) was a significant independent predictor of carotid stenosis and occlusion, but not of carotid plaque area, supporting the hypothesis that the effect of Lp(a) on atherogenesis and cardiovascular risk is largely related to thrombosis and impaired fibrinolysis. Stenosis and occlusion may not be attributable to plaque progression, but to plaque rupture and thrombosis; this relationship may also apply to other arterial beds. © 2008 American Heart Association, Inc

    Chromium stable isotope distributions in the southwest Pacific Ocean and constraints on hydrothermal input from the Kermadec Arc

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    Special attention has been given to chromium (Cr) as a paleoproxy tracing redox cycling throughout Earth’s history, due to differences in the solubility of its primary redox species at Earth’s surface (Cr (III) and Cr(VI)) and isotope fractionation associated with their interconversion. In turn, chromium’s pale- oproxy potential has motivated studies of the modern ocean to better understand which processes drive its cycling and to constrain their impact on the Cr isotope composition (d53Cr) of seawater. Here, we pre- sent total dissolved seawater Cr concentrations and d53Cr along the GEOTRACES GP13 section. This sec- tion is a zonal transect extending from Australia in the subtropical southwest Pacific Ocean. Surface signals of local biological Cr cycling are minimal, in agreement with distributions of dissolved major nutrients as well as biologically-controlled trace metals in this low productivity, oligotrophic environ- ment. Depth profiles have Cr concentration minima in surface waters and maxima at depth, and are lar- gely shaped by the advection of nutrient- and Cr-rich subsurface waters rather than vertically-driven processes. Samples close to the sediment–water interface indicate important benthic Cr fluxes across the section. The GP13 transect crosses the hydrothermally-active Kermadec Arc. Hydrothermal fluids (consisting of <15% background seawater) were collected from three venting sites at the Brothers Volcano (along the Kermadec Arc). These fluids yielded near-crustal d53Cr values (!0.17 to +0.08‰) and elevated [Cr] (7.5–23 nmol kg!1, hydrothermal endmember [Cr] % 8–27 nmol kg!1), indicating that the Kermadec Arc may be an isotopically light Cr source. Dissolved [Fe] enrichments have been reported previously in deep waters ($1600–3000 m) along the GP13 transect, east of the Kermadec Arc. These same waters show ele- vated [Cr] compared to Circumpolar Deep Water ([Cr] = 3.88 ± 0.11, d53Cr = 0.89 ± 0.08, n = 32), with an aver- age [Cr] accumulation of 0.71 ± 0.11 nmol kg!1 (1 SD), and an estimated d53Cr of +0.46 ± 0.30‰ (2 SD, n = 9) for the accumulated Cr. Comparing high-temperature vent and neutrally buoyant plume data, hydrothermal-sourced Cr is likely negligable compared to Cr contributions from other processes (benthic fluxes, release from particles), and the advection of more Cr-rich Pacific Deep Water. It is unlikely that hydrothermal vents would be a major contributor within the regional or global biogeochemical Cr cycle, even if hydrothermal fluxes change by orders of magnitude, and therefore d53Cr trends in the paleorecord may be attributable, at least in part, to major changes in other controls on Cr (e.g. widespread anoxia)

    The Position of High Frequency Waves with Respect to the Granulation Pattern

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    High frequency velocity oscillations were observed in the spectral lines Fe I 543.45nm and 543.29nm, using 2D spectroscopy with a Fabry- Perot and speckle reconstruction, at the VTT in Tenerife. We investigate the radial component of waves with frequencies in the range 8 - 22mHz in the internetwork, network and a pore. We find that the occurrence of waves do not show any preference on location and are equally distributed over down-flows and up-flows, regardless of the activity of the observed area in the line of Fe I 543.45nm. The waves observed in the lower formed line of Fe I 543.29nm seem to appear preferentially over down-flows.Comment: Article has 12 pages and 7 images. It is accepted in Solar Physics Journa

    Copper-nickel-rich, amalgamated ferromanganese crust-nodule deposits from Shatsky Rise, NW Pacific

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    A unique set of ferromanganese crusts and nodules collected from Shatsky Rise (SR), NW Pacific, were analyzed for mineralogical and chemical compositions, and dated using Be isotopes and cobalt chronometry. The composition of these midlatitude, deep-water deposits is markedly different from northwest-equatorial Pacific (PCZ) crusts, where most studies have been conducted. Crusts and nodules on SR formed in close proximity and some nodule deposits were cemented and overgrown by crusts, forming amalgamated deposits. The deep-water SR crusts are high in Cu, Li, and Th and low in Co, Te, and Tl concentrations compared to PCZ crusts. Thorium concentrations (ppm) are especially striking with a high of 152 (mean 56), compared to PCZ crusts (mean 11). The deep-water SR crusts show a diagenetic chemical signal, but not a diagenetic mineralogy, which together constrain the redox conditions to early oxic diagenesis. Diagenetic input to crusts is rare, but unequivocal in these deep-water crusts. Copper, Ni, and Li are strongly enriched in SR deep-water deposits, but only in layers older than about 3.4 Ma. Diagenetic reactions in the sediment and dissolution of biogenic calcite in the water column are the likely sources of these metals. The highest concentrations of Li are in crust layers that formed near the calcite compensation depth. The onset of Ni, Cu, and Li enrichment in the middle Miocene and cessation at about 3.4 Ma were accompanied by changes in the deep-water environment, especially composition and flow rates of water masses, and location of the carbonate compensation depth. Key Points - Fe-Mn crusts can have a diagenetic component - Mid-latitude N. Pacific deep-water Fe-Mn crusts are uniquely enriched in Cu, Th, Li - Temporal changes in deep-ocean geochemical processes are recorde
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