Multi-proxy record of ocean-climate variability during the last two millennia on the Mackenzie Shelf, Beaufort Sea

A 2,000 year-long oceanographic history, in sub-centennial resolution, from a Canadian Beaufort Sea continental shelf site (60 meters water depth) near the Mackenzie River outlet is reconstructed from ostracode and foraminifera faunal assemblages, shell stable isotopes (δ18O, δ13C) and sediment biogenic silica. The chronology of three sediment cores making up the composite section was established using 137Cs and 210Pb dating for the most recent 150 years and combined with linear interpolation of radiocarbon dates from bivalve shells and foraminifera tests. Continuous centimeter-sampling of the multicore and high-resolution sampling of a gravity and piston core yielded a time-averaged faunal record of every ~40 years from 0 to 1850 CE and every ~24 years from 1850 to 2013 CE. Proxy records were consistent with temperature oscillations and related changes in organic carbon cycling associated with the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA). Abundance changes in dominant microfossil species, such as the ostracode Paracyprideis pseudopunctillata and agglutinated foraminifers Spiroplectammina biformis and S. earlandi, are used as indicators of less saline, and possibly corrosive/turbid bottom conditions associated with the MCA (~800-1200 CE) and the most recent ~60 years (1950-2013). During these periods, pronounced fluctuations in these species suggest that prolonged seasonal sea-ice melting, changes in riverine inputs and sediment dynamics affected the benthic environment. Taxa analyzed for stable oxygen isotope composition of carbonates show the lowest δ18O values during intervals within the MCA and the highest during the late LIA, which is consistent with a 1° to 2°C cooling of bottom waters. Faunal and isotopic changes during the cooler LIA (1300-1850 CE) are most apparent at ~1500-1850 CE and are particularly pronounced during 1850 to ~1900 CE, with a ~0.5 per mil increase in δ18O values of carbonates from median values in the analyzed taxa. This very cold 50-year period suggests that enhanced summer sea ice suppressed productivity, which is indicated by low sediment biogenic silica values and lower δ13C values in analyzed species. From 1900 CE to present, declines in calcareous faunal assemblages and changes in dominant species (Cassidulina reniforme and P. pseudopunctillata) are associated with less hospitable bottom waters, indicated by a peak in agglutinated foraminifera from 1950-1990 CE

Hygge, Hope and Higher Education: A Case Study of Denmark

Higher education institutions have been profoundly reshaped by processes associated with neoliberalism. In this chapter, Larsen outlines the ways in which Denmark has ushered in marketdriven reforms to the Danish higher education system to enhance their institutional competitiveness over the past 30 years. Research on the impacts of neoliberal higher education reforms on faculty is reviewed and the author discusses her experiences (at a Canadian university) with market-driven, accountability reforms. The chapter shifts direction and provides the reader with an overview of the concept of hygge, an idealized Danish term that has connotations of coziness, safety, friendliness, and intimacy. Larsen recounts her experiences as a Canadian academic on sabbatical at a Danish university in 2017, illustrating the ways in which she experienced hygge in the Danish university setting. In the final section of the chapter, Larsen argues that hygge can be viewed as a retreat from the individualism, competition, market stratification and other challenges associated with neoliberalism. Hygge marks out the boundaries between the cold and heartless market-place and the warm and cozy home, and despite critiques that is instantiates exclusions, hygge offers hope to resist the alienation associated with neoliberalism and provide an alternative ethos for close and safe social relations within academia

On Glauber modes in Soft-Collinear Effective Theory

Gluon interactions involving spectator partons in collisions at hadronic machines are investigated. We find a class of examples in which a mode, called Glauber gluons, must be introduced to the effective theory for consistency.Comment: 19 pages, three figures. Uses JHEP3.cl

Flat Clathrin Lattices: stable features of the plasma membrane

Clathrin-mediated endocytosis (CME) is a fundamental property of eukaryotic cells. Classical CME proceeds via the formation of clathrin-coated pits (CCP) at the plasma membrane that invaginate to form clathrin-coated vesicles; a process that is well understood. However, clathrin also assembles into flat clathrin lattices (FCL); these structures remain poorly described and their contribution to cell biology is unclear. We have used quantitative imaging to provide the first comprehensive description of FCL and explore their influence on plasma membrane organization. Ultrastructural analysis by electron and super-resolution microscopy revealed two discrete populations of clathrin structures. CCP were typified by their sphericity, small size and homogeneity. FCL were planar, large and heterogeneous, and present on both the dorsal and ventral surfaces of cells. Live microscopy demonstrated that CCP are short-lived and culminate in a peak of dynamin recruitment, consistent with classical CME. In contrast, FCL were long-lived with sustained association with dynamin. We investigated the biological relevance of FCL using the chemokine receptor CCR5 as a model system. Agonist activation leads to sustained recruitment of CCR5 to FCL. Quantitative molecular imaging indicated that FCL partitioned receptors at the cell surface. Our observations suggest that FCL provide stable platforms for the recruitment of endocytic cargo

Syntenator: Multiple gene order alignments with a gene-specific scoring function

<p>Abstract</p> <p>Background</p> <p>Identification of homologous regions or conserved syntenies across genomes is one crucial step in comparative genomics. This task is usually performed by genome alignment softwares like WABA or blastz. In case of conserved syntenies, such regions are defined as conserved gene orders. On the gene order level, homologous regions can even be found between distantly related genomes, which do not align on the nucleotide sequence level.</p> <p>Results</p> <p>We present a novel approach to identify regions of conserved synteny across multiple genomes. Syntenator represents genomes and alignments thereof as partial order graphs (POGs). These POGs are aligned by a dynamic programming approach employing a gene-specific scoring function. The scoring function reflects the level of protein sequence similarity for each possible gene pair. Our method consistently defines larger homologous regions in pairwise gene order alignments than nucleotide-level comparisons. Our method is superior to methods that work on predefined homology gene sets (as implemented in Blockfinder). Syntenator successfully reproduces 80% of the EnsEMBL man-mouse conserved syntenic blocks. The full potential of our method becomes visible by comparing remotely related genomes and multiple genomes. Gene order alignments potentially resolve up to 75% of the EnsEMBL 1:many orthology relations and 27% of the many:many orthology relations.</p> <p>Conclusion</p> <p>We propose Syntenator as a software solution to reliably infer conserved syntenies among distantly related genomes. The software is available from <url>http://www2.tuebingen.mpg.de/abt4/plone</url>.</p

Conditioned Effects Produced by Naltrexone Doses That Reduce Ethanol-Reinforced Responding in Rhesus Monkeys

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66264/1/j.1530-0277.1999.tb04173.x.pd

CD74 deficiency ameliorates Pseudomonas aeruginosa-induced ocular infection

Eye trauma and contact lens wear are the main factors that predispose to the development of infectious keratitis. The existing therapies fail to control the inflammation-driven tissue damage that occurs during Pseudomonas aeruginosa infection. Antibiotic treatment reduces bacterial burdens, but better interventions are needed to alleviate tissue damage resulting from local inflammation. We have previously documented that inhibition of macrophage migration inhibitory factor (MIF) reduces the bacterial levels and the inflammatory damage during keratitis. Here, we report that mice deficient for CD74, the putative MIF receptor, developed milder Pseudomonas aeruginosa-induced disease, characterized by decreased proinflammatory mediators and reduced bacterial presence in the cornea. However, topical inhibition of MIF using antibodies applied to the cornea further promoted recovery from disease, suggesting that in addition to MIF-dependent signaling events, MIF-triggered CD74-independent signaling pathways regulate sensitization to P. aeruginosa-induced infection

Disorder Effects on Exciton-Polariton Condensates

The impact of a random disorder potential on the dynamical properties of Bose Einstein condensates is a very wide research field. In microcavities, these studies are even more crucial than in the condensates of cold atoms, since random disorder is naturally present in the semiconductor structures. In this chapter, we consider a stable condensate, defined by a chemical potential, propagating in a random disorder potential, like a liquid flowing through a capillary. We analyze the interplay between the kinetic energy, the localization energy, and the interaction between particles in 1D and 2D polariton condensates. The finite life time of polaritons is taken into account as well. In the first part, we remind the results of [G. Malpuech et al. Phys. Rev. Lett. 98, 206402 (2007).] where we considered the case of a static condensate. In that case, the condensate forms either a glassy insulating phase at low polariton density (strong localization), or a superfluid phase above the percolation threshold. We also show the calculation of the first order spatial coherence of the condensate versus the condensate density. In the second part, we consider the case of a propagating non-interacting condensate which is always localized because of Anderson localization. The localization length is calculated in the Born approximation. The impact of the finite polariton life time is taken into account as well. In the last section we consider the case of a propagating interacting condensate where the three regimes of strong localization, Anderson localization, and superfluid behavior are accessible. The localization length is calculated versus the system parameters. The localization length is strongly modified with respect to the non-interacting case. It is infinite in the superfluid regime whereas it is strongly reduced if the fluid flows with a supersonic velocity.Comment: chapter for a book "Exciton Polaritons in Microcavities: New Frontiers" by Springer (2012), the original publication is available at http://www.springerlink.co

ProSAAS-Derived Peptides are Colocalized with Neuropeptide Y and Function as Neuropeptides in the Regulation of Food Intake

ProSAAS is the precursor of a number of peptides that have been proposed to function as neuropeptides. Because proSAAS mRNA is highly expressed in the arcuate nucleus of the hypothalamus, we examined the cellular localization of several proSAAS-derived peptides in the mouse hypothalamus and found that they generally colocalized with neuropeptide Y (NPY), but not α-melanocyte stimulating hormone. However, unlike proNPY mRNA, which is upregulated by food deprivation in the mediobasal hypothalamus, neither proSAAS mRNA nor proSAAS-derived peptides were significantly altered by 1–2 days of food deprivation in wild-type mice. Furthermore, while proSAAS mRNA levels in the mediobasal hypothalamus were significantly lower in Cpefat/fat mice as compared to wild-type littermates, proNPY mRNA levels in the mediobasal hypothalamus and in other subregions of the hypothalamus were not significantly different between wild-type and Cpefat/fat mice. Intracerebroventricular injections of antibodies to two proSAAS-derived peptides (big LEN and PEN) significantly reduced food intake in fasted mice, while injections of antibodies to two other proSAAS-derived peptides (little LEN and little SAAS) did not. Whole-cell patch clamp recordings of parvocellular neurons in the hypothalamic paraventricular nucleus, a target of arcuate NPY projections, showed that big LEN produced a rapid and reversible inhibition of synaptic glutamate release that was spike independent and abolished by blocking postsynaptic G protein activity, suggesting the involvement of a postsynaptic G protein-coupled receptor and the release of a retrograde synaptic messenger. Taken together with previous studies, these findings support a role for proSAAS-derived peptides such as big LEN as neuropeptides regulating food intake