Renal and vascular function in women with previous preeclampsia: A comparison of low- and high-degree proteinuria

The degree of proteinuria during preeclampsia has been considered to be a marker of severity of the disease and of endothelial dysfunction. The aim of the study was to assess whether the degree of proteinuria in preeclamptic pregnancy is related to impairment of vascular dilatation and/or kidney function years after the index pregnancy. Thirty women with a history of severe preeclampsia divided into low (n=8, dU-prot <5g/day) and high (n=22, dU-prot ≥5g/day) proteinuric groups and 21 women with previous normotensive pregnancy were studied 5–6 years after index pregnancy. Renal function and blood pressure were assessed together with venous occlusion plethysmography, where changes in brachial artery blood flow, induced by intra-arterial infusions of an endothelium-independent (sodium nitroprusside) and an endothelium-dependent (acetylcholine) vasodilator, were measured. The results showed similar renal function in all groups. There was no difference in vasodilation between preeclamptic groups and controls or correlation between degree of proteinuria during index pregnancy and present vasodilation. We conclude that the degree of proteinuria during preeclampsia does not predict vascular dilatation or renal function 5–6 years after preeclamptic pregnancy

Spectroscopic and photometric studies of low-metallicity star-forming dwarf galaxies. I. SBS 1129+576

Spectroscopy and V,I CCD photometry of the dwarf irregular galaxy SBS 1129+576 are presented for the first time. The CCD images reveal a chain of compact H II regions within the elongated low-surface-brightness (LSB) component of the galaxy. Star formation takes place mainly in two high-surface-brightness H II regions. The mean (V-I) colour of the LSB component in the surface brightness interval between 23 and 26 mag/sq.arcsec is relatively blue ~0.56+/-0.03 mag, as compared to the (V-I)~0.9-1.0 for the majority of known dwarf irregular and blue compact dwarf (BCD) galaxies. Spectroscopy shows that the galaxy is among the most metal-deficient galaxies with an oxygen abundance 12+log(O/H)= 7.36+/-0.10 in the brightest H II region and 7.48+/-0.12 in the second brightest H II region, or 1/36 and 1/28 of the solar value, respectively. Hbeta and Halpha emission lines and Hdelta and Hgamma absorption lines are detected in a large part of the LSB component. We use two extinction-insensitive methods based on the equivalent widths of (1) emission and (2) absorption Balmer lines to put constraints on the age of the stellar populations in the galaxy. In addition, we use two extinction-dependent methods based on (3) the spectral energy distribution (SED) and (4) the (V-I) colour. The observed properties of the LSB component can be reproduced by a stellar population forming continuously since 10 Gyr ago, provided that the star formation rate has increased during the last 100 Myr by a factor of 6 to 50 and no extinction is present. However, the observational properties of the LSB component can be reproduced equally well by continuous star formation which started not earlier than 100 Myr ago and stopped at 5 Myr, if some extinction is assumed.(Abridged)Comment: 17 pages, 12 figures, Accepted for publication in A&

A study of HI-selected galaxies in the Hercules cluster

The present study is aimed at a sample of 22 galaxies detected in the blind VLA HI survey of the Hercules cluster by Dickey (1997), 18 of which were selected on an HI line width smaller than 270 km/s and 4 others with only tentative optical counterparts on the Palomar Sky Survey. Sensitive single-dish HI line spectra were obtained for 20 of them, and for one (47-154) the VLA detection was not confirmed. Optical surface photometry was obtained of 10 objects, for 8 of which optical spectroscopy was obtained as well. Based on various selection criteria, two (ce-143 and ne-204) can be classified as dwarfs. The objects of which optical observations were made show star formation properties similar to those of published samples of actively star forming galaxies, and approximately half of them have properties intermediate between those of dwarf galaxies and low-luminosity disc galaxies. No optical redshifts could be obtained for two of the galaxies (sw-103 and sw-194) and their physical association with the HI clouds detected at their positions therefore remains uncertain. Unique among the objects is the Tidal Dwarf Galaxy ce-061 in a tail of the IC 1182 merger system.Comment: 20 pages, 19 figures, accepted for publication in A&

I Zw 18 as morphological paradigm for rapidly assembling high-z galaxies

IZw18, ever since regarded as the prototypical blue compact dwarf (BCD) galaxy, is, quite ironically, the most atypical BCD known. This is because its large exponential low-surface brightness envelope is not due to an old stellar host but entirely due to extended nebular emission (ne) (Papaderos et al. 2002; P02). We study IZw18 and IZw18C down to an unprecedently faint surface brightness level using HST ACS data. We argue that the properties of IZw18C can be consistently accounted for by propagating star formation over the past ~100 Myr, in combination with stellar diffusion and the associated radial stellar mass filtering effect (P02). As for IZw18, we find that ne extends out to ~16 stellar scale lengths and provides at least 1/3 of the total optical emission. The case of IZw18 suggests caution in studies of distant galaxies in dominant stages of their evolution, rapidly assembling their stellar mass at high specific star formation rates (SSFRs). It calls attention to the fact that ne is not necessarily cospatial with the underlying ionizing and non-ionizing stellar background, neither has to scale with its surface density. The prodigious energetic output during dominant phases of galaxy evolution may result in large exponential ne envelopes, extending much beyond the still compact stellar component, just like in IZw18. Therefore, the morphological paradigm of IZw18, while probably unique in the nearby Universe, may be ubiquitous among high-SSFR galaxies at high redshift. Using IZw18 as reference, we show that extended ne may introduce substantial observational biases and significantly affect fundamental galaxy relations. Among others, we show that the surface brightness profiles of distant morphological analogs to IZw18 may be barely distinguishable from Sersic profiles with an exponent 2<n<5, thus mimicking the profiles of massive galaxy spheroids. (abridged)Comment: 22 pages, 15 figures, Accepted for publication in Astronomy and Astrophysic

The evolutionary status of the low-metallicity blue compact dwarf galaxy SBS 0940+544

We present the results of spectrophotometry and V,R,I, Halpha CCD photometry of the blue compact dwarf (BCD) galaxy SBS 0940+544. Broad-band images taken with the 2.1m KPNO and 1.23m Calar Alto telescopes reveal a compact high-surface-brightness H II region with ongoing star formation, located at the northwestern tip of the elongated low surface brightness (LSB) main body of the BCD. High signal-to-noise 4.5m Multiple Mirror Telescope (MMT) and 10m Keck II telescope long-slit spectroscopy of SBS 0940+544 is used to derive element abundances of the ionized gas in the brightest H II region and to study the stellar population in the host galaxy. The oxygen abundance in the brightest region with strong emission lines is 12+log(O/H) = 7.46-7.50, or 1/29-1/26 solar, in agreement with earlier determinations and among the lowest for BCDs. Hbeta and Halpha emission lines and Hdelta and Hgamma absorption lines are detected in a large part of the main body. Three methods are used to put constraints on the age of the stellar population at different positions along the major axis. They are based on (a) the equivalent widths of the emission lines, (b) the equivalent widths of the absorption lines and (c) the spectral energy distributions (SED). Several scenarios of star formation have been considered. The observed properties in the main body can be reproduced by a continuous star formation process which started not earlier than 100 Myr ago, if a small extinction is assumed. However, the observations can be reproduced equally well by a stellar population forming continuously since 10 Gyr ago, if the star formation rate has increased during the last 100 Myr in the main body of SBS 0940+544 by at least a factor of five. In summary, we find no compelling evidence which favors either a young or an old age of SBS 0940+544.Comment: 20 pages, 15 Postscript figures, accepted for publication in the Astronomy and Astrophysic

Microbial metagenomes from three aquifers in the Fennoscandian shield terrestrial deep biosphere reveal metabolic partitioning among populations

Microorganisms in the terrestrial deep biosphere host up to 20% of the earth's biomass and are suggested to be sustained by the gases hydrogen and carbon dioxide. A metagenome analysis of three deep subsurface water types of contrasting age (from &lt;20 to several thousand years) and depth (171 to 448 m) revealed phylogenetically distinct microbial community subsets that either passed or were retained by a 0.22 mu m filter. Such cells of &lt;0.22 mu m would have been overlooked in previous studies relying on membrane capture. Metagenomes from the three water types were used for reconstruction of 69 distinct microbial genomes, each with &gt;86% coverage. The populations were dominated by Proteobacteria, Candidate divisions, unclassified archaea and unclassified bacteria. The estimated genome sizes of the &lt;0.22 mu m populations were generally smaller than their phylogenetically closest relatives, suggesting that small dimensions along with a reduced genome size may be adaptations to oligotrophy. Shallow 'modern marine' water showed community members with a predominantly heterotrophic lifestyle. In contrast, the deeper, 'old saline' water adhered more closely to the current paradigm of a hydrogen-driven deep biosphere. The data were finally used to create a combined metabolic model of the deep terrestrial biosphere microbial community.Supplementary information available for this article at http://www.nature.com/ismej/journal/v10/n5/suppinfo/ismej2015185s1.html</p