Redox Chemistry and Molybdenum Burial in a Mesoproterozoic Lake

While marine sediments have been used to constrain a history of redox chemistry throughout the Precambrian, far fewer data have been generated from lakes. With major biological innovations thought to have occurred in Proterozoic lakes, understanding their chemistry is critical for understanding the evolution of eukaryotic life. We use sediment geochemistry to characterize the redox conditions of the Nonesuch Formation (~1.1 Ga) and a modern analogue for the Proterozoic: the Middle Island Sinkhole in Lake Huron (USA). Iron speciation, Mo contents, and Mo‐U covariation demonstrate oxic and anoxic—not euxinic—environments, with no clear indicators of enhanced biological productivity in the Nonesuch Formation. Moderate Mo enrichments observed in the Nonesuch Formation are not attributed to euxinia, but instead to an authigenic particulate shuttle. We suggest that the Fe and Mo sediment geochemistry of these lacustrine systems reflect only local water column and sediment burial conditions and not atmospheric oxygenation.Plain Language SummaryLakes are proposed to have been critical environments for the evolution of life during the Proterozoic (~2.5 to 0.5 billion years ago). However, relatively little is known about the chemistry of ancient lakes, including the availability of oxygen for biological productivity, and how local oxygen availability can be extrapolated to understand global oxygen availability. In addition, with no lakes remaining from the Proterozoic, the only way to study ancient lakes is to use the chemistry of the sediments left behind. This study uses the sediment chemistry of elements that are sensitive to oxygen to understand oxygen availability in a Proterozoic lake environment. These data were then compared to modern lake environments with known chemistry and oxygen levels in order to interpret the results better. We found that oxygen availability in the Proterozoic lake was variable, with no clear indicators of abundant biological productivity. We conclude that ancient lake sediments only constrain the chemistry of the local environment, with no major implications for global or even regional atmospheric oxygenation.Key PointsFe, Mo, and U sediment geochemistry of the Nonesuch Formation (~1.1 Ga; USA) indicate fluctuating oxic and anoxic redox chemistryMo and U covariation in the Nonesuch Formation and modern analogue sediments confirm euxinia is not necessary for moderate Mo burialComparison of Nonesuch Formation and modern analogue indicates that Proterozoic lakes are unlikely to constrain atmospheric oxygenPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150528/1/grl59087_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150528/2/grl59087.pd

SDSS-RASS: Next Generation of Cluster-Finding Algorithms

We outline here the next generation of cluster-finding algorithms. We show how advances in Computer Science and Statistics have helped develop robust, fast algorithms for finding clusters of galaxies in large multi-dimensional astronomical databases like the Sloan Digital Sky Survey (SDSS). Specifically, this paper presents four new advances: (1) A new semi-parametric algorithm - nicknamed ``C4'' - for jointly finding clusters of galaxies in the SDSS and ROSAT All-Sky Survey databases; (2) The introduction of the False Discovery Rate into Astronomy; (3) The role of kernel shape in optimizing cluster detection; (4) A new determination of the X-ray Cluster Luminosity Function which has bearing on the existence of a ``deficit'' of high redshift, high luminosity clusters. This research is part of our ``Computational AstroStatistics'' collaboration (see Nichol et al. 2000) and the algorithms and techniques discussed herein will form part of the ``Virtual Observatory'' analysis toolkit.Comment: To appear in Proceedings of MPA/MPE/ESO Conference "Mining the Sky", July 31 - August 4, 2000, Garching, German

The impact of Cochrane Systematic Reviews : a mixed method evaluation of outputs from Cochrane Review Groups supported by the UK National Institute for Health Research

© 2014 Bunn et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: There has been a growing emphasis on evidence-informed decision making in health care. Systematic reviews, such as those produced by the Cochrane Collaboration, have been a key component of this movement. The UK National Institute for Health Research (NIHR) Systematic Review Programme currently supports 20 Cochrane Review Groups (CRGs). The aim of this study was to identify the impacts of Cochrane reviews published by NIHR funded CRGs during the years 2007-11. Methods: We sent questionnaires to CRGs and review authors, interviewed guideline developers and used bibliometrics and documentary review to get an overview of CRG impact and to evaluate the impact of a sample of 60 Cochrane reviews. We used a framework with four categories (knowledge production, research targeting, informing policy development, and impact on practice/services). Results: A total of 1502 new and updated reviews were produced by the 20 NIHR funded CRGs between 2007-11. The clearest impacts were on policy with a total of 483 systematic reviews cited in 247 sets of guidance; 62 were international, 175 national (87 from the UK) and 10 local. Review authors and CRGs provided some examples of impact on practice or services, for example safer use of medication, the identification of new effective drugs or treatments and potential economic benefits through the reduction in the use of unproven or unnecessary procedures. However, such impacts are difficult to objectively document and the majority of reviewers were unsure if their review had produced specific impacts. Qualitative data suggested that Cochrane reviews often play an instrumental role in informing guidance although a poor fit with guideline scope or methods, reviews being out of date and a lack of communication between CRGs and guideline developers were barriers to their use. Conclusions: Health and economic impacts of research are generally difficult to measure. We found that to be the case with this evaluation. Impacts on knowledge production and clinical guidance were easier to identify and substantiate than those on clinical practice. Questions remain about how we define and measure impact and more work is needed to develop suitable methods for impact analysis.Peer reviewe

Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes

The virulence of many Gram-positive bacteria depends on cholesterol-dependent cytolysins (CDCs), which form pores in eukaryotic cell plasma membranes. Pyolysin (PLO) from Trueperella pyogenes provided a unique opportunity to explore cellular responses to CDCs because it does not require thiol activation. Sublytic concentrations of PLO stimulated phosphorylation of MAPK ERK and p38 in primary stromal cells, and induced autophagy as determined by protein light-chain 3B cleavage. Although, inhibitors of MAPK or autophagy did not affect PLO-induced cytolysis. However, 10 μM 3-hydroxynaphthalene-2-carboxylic acid-(3,4-dihydroxybenzylidene)-hydrazide (Dynasore), a dynamin guanosine 5′-triphosphatase inhibitor, protected stromal cells against PLO-induced cytolysis as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (85 ± 17% versus 50 ± 9% cell viability), measuring extracellular ATP, and kinetic assays. This was a generalized mechanism because Dynasore also protected HeLa cells against streptolysin O. Furthermore, the effect was reversible, with stromal cell sensitivity to PLO restored within 30 minutes of Dynasore removal. The protective effect of Dynasore was not conferred by dynamin inhibition, induction of ERK phosphorylation, or Dynasore binding to PLO. Rather, Dynasore reduced cellular cholesterol and disrupted plasma membrane lipid rafts, similar to positive control methyl-β-cyclodextrin. Dynasore is a tractable tool to explore the complexity of cholesterol homeostasis in eukaryotic cells and to develop strategies to counter CDCs.—Preta, G., Lotti, V., Cronin, J. G., and Sheldon, I. M. Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes

Renal oncocytoma: a comparative clinicopathologic study and fluorescent in-situ hybridization analysis of 73 cases with long-term follow-up

Clinical studies have confirmed that renal oncocytoma (RO) is a benign neoplasm with excellent prognosis. In diagnostically challenging cases of renal oncocytic epithelial neoplasms, fluorescent in-situ hybridization (FISH) is increasingly being used and its ability to distinguish RO from chromophobe renal cell carcinoma (ChRCC) has been documented. In this study, we evaluated the differential diagnostic contribution of FISH in cases of RO

The galaxy-mass correlation function measured from weak lensing in the Sloan Digital Sky Survey

We present galaxy-galaxy lensing measurements over scales 0.025 to 10 h(-1) Mpc in the Sloan Digital Sky Survey (SDSS). Using a flux-limited sample of 127,001 lens galaxies with spectroscopic redshifts and mean luminosity [L] similar to L-* and 9,020,388 source galaxies with photometric redshifts, we invert the lensing signal to obtain the galaxy-mass correlation function xi(gm). We find xi(gm) is consistent with a power law, xi(gm) (r = r(0))(-gamma), with best-fit parameters gamma = 1.79 +/- 0.06 and r(0) (5.4 +/- 0.7) (0.27/Omega(m))(1/gamma) h(-1) Mpc. At fixed separation, the ratio xi(gg)/xi(gm) = b/r, where b is the bias and r is the correlation coefficient. Comparing with the galaxy autocorrelation function for a similarly selected sample of SDSS galaxies, we find that b/r is approximately scale-independent over scales 0.2 - 6.7 h(-1) Mpc, with mean [b/r] = (1.3 +/- 0.2) (Omega(m)/0.27). We also find no scale dependence in b/r for a volume-limited sample of luminous galaxies (-23.0 < M-r < -21.5). The mean b/r for this sample is [b/r](Vlim) = (2.0 +/- 0.7) (Omega(m)/0.27). We split the lens galaxy sample into subsets based on luminosity, color, spectral type, and velocity dispersion and see clear trends of the lensing signal with each of these parameters. The amplitude and logarithmic slope of xi(gm) increase with galaxy luminosity. For high luminosities (L similar to 5 L-*), xi(gm) deviates significantly from a power law. These trends with luminosity also appear in the subsample of red galaxies, which are more strongly clustered than blue galaxies

Cabibbo Mixing and the Search for CP Violation

We examine certain extensions of the standard model in which $CP$ violation is spontaneous and the strong $CP$ problem is resolved. In these models, the $3 \times 3$ quark mixing matrix is neither real nor unitary. However, to a precision of 0.1%, it is real and orthogonal. There are no readily observable $CP$-violating effects besides those in the neutral kaon system.Comment: 6 pages, latex, no figure