Paleocene Cyclic Sedimentation in the Western North Atlantic, ODP Site 1051, Blake Nose

Upper Paleocene (zone CP8b) cyclic sediment from Ocean Drilling Program (ODP) Site 1051 on Blake Nose, western North Atlantic, alternates from white carbonate-rich to green carbonate-poor in response to precessional forcing. Compositional differences between the two bed types are minor: mineral and nannofossil composition of the beds vary subtly, but grain size of the terrigenous component and biogenic silica content remain constant. Iron content determined by sediment magnetic susceptibility and iron intensity determined by a core-scanning XRF correlates negatively with carbonate content and are higher in green beds. Kaolinite content of green beds is slightly higher as well. Green beds exhibit lower evenness values than white beds for nannofossil assemblages and are more dominated by the species Coccolithus. Dominance by Coccolithus indicates more mesotrophic conditions over Blake Nose during deposition of the green beds, which correlates with slightly higher iron and kaolinite contents. The absence of change in terrigenous grain size and the absence of any indication of planktonic blooms indicate that there was a minor, most likely eolian, input of iron and kaolinite during deposition of the green beds. The source area was most likely northwest Africa, which supplied iron and kaolinite when source areas deflated under drier conditions. With this scenario, kaolinite is an indicator of drier climate and source area erosion, rather than the warmer and/or wetter conditions under which it forms in soils. During precessional minima or perihelion summer (the opposite of our current configuration), there was an increased range of seasonal temperatures and an increase in the intensity of summer and winter monsoon circulation. As a consequence, there was more rainfall in northern Africa and drier conditions in the continental interiors at mid-latitudes. Green bed deposition occurred during precessional maxima when the North Atlantic was cooler, northwest Africa drier, and the eolian flux to the western North Atlantic slightly increased

Century-scale records of land-based activities recorded in Mesoamerican coral cores

Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Marine Pollution Bulletin 58 (2009): 1835-1842, doi:10.1016/j.marpolbul.2009.07.024.The Mesoamerican Reef, the second-largest barrier reef in the world, is located in the western Caribbean Sea off the coasts of Mexico, Belize, Guatemala, and Honduras. Particularly in the south, the surrounding watersheds are steep and the climate is extremely wet. With development and agricultural expansion, the potential for negative impacts to the reef from land-based runoff becomes high. We constructed annually resolved century-scale records of metal/calcium ratios in coral skeletons collected from four sites experiencing a gradient of land-based runoff. Our proxy data indicate that runoff onto the reef has increased relatively steadily over time at all sites, consistent with land use trends from historical records. Sediment supply to the reef is greater in the south, and these more exposed reefs will probably benefit most immediately from management that targets runoff reduction. However, because runoff at all sites is steadily increasing, even distal sites will benefit from watershed management.This research was supported by funds from the PADI Foundation, B. Katz, two anonymous donors and the Edna Bailey Sussman Foundation to J.C

Data report: High-resolution stable isotope stratigraphy of the late Middle Eocene at Site 1051, Blake Nose

The primary aim of the this investigation was to examine the stability of subtropical sea-surface temperatures and reconstruct the surfaceto- benthos thermal gradient. High-resolution stable isotopic analyses (δ18O and δ13C) were conducted on late middle Eocene planktonic and benthic foraminifers recovered from Hole 1051B, Blake Nose, western North Atlantic. The sequence comprises a siliceous nannofossil and foraminifer ooze, with well-preserved calcareous microfossils. Isotopic examination was conducted on the mixed-layer dweller Morozovella spinulosa and the benthic foraminifer Nuttalides truempyi at this subtropical site

Local Stressors Reduce Coral Resilience to Bleaching

Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2–3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change

Genome-Wide Association Study Identifies Loci for Liver Enzyme Concentrations in Mexican Americans: The GUARDIAN Consortium.

ObjectivePopulations of Mexican American ancestry are at an increased risk for nonalcoholic fatty liver disease. The objective of this study was to determine whether loci in known and novel genes were associated with variation in aspartate aminotransferase (AST) (n = 3,644), alanine aminotransferase (ALT) (n = 3,595), and gamma-glutamyl transferase (GGT) (n = 1,577) levels by conducting the first genome-wide association study (GWAS) of liver enzymes, which commonly measure liver function, in individuals of Mexican American ancestry.MethodsLevels of AST, ALT, and GGT were determined by enzymatic colorimetric assays. A multi-cohort GWAS of individuals of Mexican American ancestry was performed. Single-nucleotide polymorphisms (SNP) were tested for association with liver outcomes by multivariable linear regression using an additive genetic model. Association analyses were conducted separately in each cohort, followed by a nonparametric meta-analysis.ResultsIn the PNPLA3 gene, rs4823173 (P = 3.44 × 10-10 ), rs2896019 (P = 7.29 × 10-9 ), and rs2281135 (P = 8.73 × 10-9 ) were significantly associated with AST levels. Although not genome-wide significant, these same SNPs were the top hits for ALT (P = 7.12 × 10-8 , P = 1.98 × 10-7 , and P = 1.81 × 10-7 , respectively). The strong correlation (r2  = 1.0) for these SNPs indicated a single hit in the PNPLA3 gene. No genome-wide significant associations were found for GGT.ConclusionsPNPLA3, a locus previously identified with ALT, AST, and nonalcoholic fatty liver disease in European and Japanese GWAS, is also associated with liver enzymes in populations of Mexican American ancestry

Egg Laying Behaviour and Larval Shelter-Construction Patterns of the endangered Mottled Duskywing (Erynnis martialis) in Canada

The Mottled duskywing (Erynnis martialis) butterfly is endangered, living in pine forests and oak barrens in Canada and the eastern United States of America. While host plants and larval behaviour is documented in Mottled duskywing’s eastern range, these life components are poorly known in Manitoba. We observed adult behaviour, host plant species used and larval foraging to better understand these biological aspects of E. martialis. We observed eggs laid exclusively on Ceanothus herbaceus, and larvae consuming C. herbaceus in leaf shelters near the periphery of plants. Early instar larvae tied leaves together with cells of silk creating partly open shelters while later instar larvae completely sealed shelters. Shelters constructed out of young leaves at the edge of plants are likely easier to digest. Later-instar larvae may nocturnally harvest food to consume in shelters during the day to reduce predation risk. Larvae were found in clearings adjacent to Pinus banksiana dominated forests, with these openings likely providing suitable microhabitats for egg development and larval feeding. We observed newly emerged adults during weeks 1 to 5 of the flight period; eggs, larvae and adults overlapped. We recommend direct observations of larval foraging—during the day and night, as well as transitions into and out of diapause—to more accurately describe their behaviour and physiology. We started to characterise microhabitats, however further research is needed. Our research may help to guide critical habitat designations, leading to successful Mottled duskywing recovery in Manitoba."Funding was provided by the Canadian Wildlife Service (Environment and Climate Change Canada, Government of Canada) and an Alliance Grant from the Natural Sciences and Engineering Research Council of Canada. JH thanks the support for publication fees by the University of Winnipeg Graduate Student Travel / Publication Grant."https://bioone.org/journals/the-journal-of-the-lepidopterists-society/volume-76/issue-1/lepi.76i1.a6/Egg-Laying-Behaviour-and-Larval-Shelter-Construction-Patterns-of-the/10.18473/lepi.76i1.a6.shor

The Spectral Energy Distribution of Powerful Starburst Galaxies I : Modelling the Radio Continuum

This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.We have acquired radio-continuum data between 70MHz and 48 GHz for a sample of 19 southern starburst galaxies at moderate redshifts (0.067 < z < 0.227) with the aim of separating synchrotron and free-free emission components. Using a Bayesian framework, we find the radio continuum is rarely characterized well by a single power law, instead often exhibiting lowfrequency turnovers below 500 MHz, steepening at mid to high frequencies, and a flattening at high frequencies where free-free emission begins to dominate over the synchrotron emission. These higher order curvature components may be attributed to free-free absorption across multiple regions of star formation with varying optical depths. The decomposed synchrotron and free-free emission components in our sample of galaxies form strong correlations with the total-infrared bolometric luminosities. Finally, we find that without accounting for free-free absorption with turnovers between 90 and 500MHz the radio continuum at low frequency (v < 200 MHz) could be overestimated by upwards of a factor of 12 if a simple power-law extrapolation is used from higher frequencies. The mean synchrotron spectral index of our sample is constrained to be α = -1.06, which is steeper than the canonical value of -0.8 for normal galaxies. We suggest this may be caused by an intrinsically steeper cosmic ray distribution.Peer reviewe

Deciphering interplay between Salmonella invasion effectors

Bacterial pathogens have evolved a specialized type III secretion system (T3SS) to translocate virulence effector proteins directly into eukaryotic target cells. Salmonellae deploy effectors that trigger localized actin reorganization to force their own entry into non-phagocytic host cells. Six effectors (SipC, SipA, SopE/2, SopB, SptP) can individually manipulate actin dynamics at the plasma membrane, which acts as a ‘signaling hub’ during Salmonella invasion. The extent of crosstalk between these spatially coincident effectors remains unknown. Here we describe trans and cis binary entry effector interplay (BENEFIT) screens that systematically examine functional associations between effectors following their delivery into the host cell. The results reveal extensive ordered synergistic and antagonistic relationships and their relative potency, and illuminate an unexpectedly sophisticated signaling network evolved through longstanding pathogen–host interaction