Northern Ellesmere Island, 1953 And 1954

Account of the Ellesmere Ice Shelf Expeditions, organized by the Defence Research Board and Geological Survey of Canada. On reconnaissance Apr.-Aug. 1953, G.F. Hattersley-Smith and R.G. Blackadar made glaciological and geological observations west from Alert to Markham Bay (including Ross River and Feilden Peninsula), east to Cape Sheridan, and southwest along Wood River toward the United States Range. In 1954 (Apr.-Sept.), G.F. Hattersley-Smith, E.W. Marshall, A.P. Crary, and R.L. Christie made their main base on the ice shelf at Ward Hunt Island (83 05 N, 75 W), from which trips were made east to Cape Albert Edward and Cape Columbia, and west to Kruger Island on the edge of Nansen Sound, completing glaciological and geological reconnaissance of the north coast of Ellesmere. On the ice shelf near the Ward Hunt Island base, geological, geophysical, glaciological and oceanographic investigations, survey and leveling work, and meteorological observations were carried on. Reports are made on the glaciological work by G.F. Hattersley-Smith; geophysical and oceanographic studies, by A.P. Crary; and geological observations, 1954, by R.L. Christie. New place names (11) submitted to the Canadian Board on Geographical Names, also records and relics recovered from cairns of earlier expeditions, are reported. The account is introduced by a useful summary of parties visiting Northern Ellesmere 1876-1951, and of work on ice island T-3

Lipid and fatty acid composition of parasitic caligid copepods belonging to the genus Lepeophtheirus

Sea lice are copepod ectoparasites that constitute a major barrier to the sustainability and economic viability of marine finfish aquaculture operations worldwide. In particular, the salmon louse, Lepeophtheirus salmonis, poses a considerable problem for salmoniculture in the northern hemisphere. The free-swimming nauplii and infective copepodids of L. salmonis are lecithotrophic, subsisting principally on maternally-derived lipid reserves. However, the lipids and fatty acids of sea lice have been sparsely studied and therefore the present project aimed to investigate the lipid and fatty acid composition of sea lice of the genus Lepeophtheirus obtained from a variety of fish hosts. Total lipid was extracted from eggs and adult female Lepeophtheirus salmonis obtained from both wild and farmed Atlantic salmon (Salmo salar L.) sampled at two time points, in the mid 1990’s and in 2009. In addition, L. salmonis from wild sea trout (Salmo trutta L.) and L. hippoglossi from wild Atlantic halibut (Hippoglossus hippoglossus L.) were sampled and analyzed. The lipids of both females and egg strings of Lepeophtheirus were characterized by triacylglycerol (TAG) as the major neutral (storage) lipid with phosphatidylcholine and phosphatidylethanolamine as the major polar (membrane) lipids. The major fatty acids were 22:6n-3 (DHA), 18:1n-9 and 16:0, with lesser amounts of 20:5n-3, 22:5n-3 and 18:0. L. salmonis sourced from farmed salmon were characterized by higher levels of 18:2n-6 and 18:3n-3 than lice from wild salmon. Egg strings had higher levels of TAG and lower DHA compared to females, whereas L. hippoglossi had lower levels of TAG and higher DHA than L. salmonis. The results demonstrate that the fatty acid compositions of lice obtained from wild and farmed salmon differ and that changes to the lipid and fatty acid composition of feeds for farmed salmon influence the louse compositions

A solution scan of societal options to reduce transmission and spread of respiratory viruses: SARS-CoV-2 as a case study

Societal biosecurity – measures built into everyday society to minimize risks from pests and diseases – is an important aspect of managing epidemics and pandemics. We aimed to identify societal options for reducing the transmission and spread of respiratory viruses. We used SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) as a case study to meet the immediate need to manage the COVID-19 pandemic and eventually transition to more normal societal conditions, and to catalog options for managing similar pandemics in the future. We used a ‘solution scanning’ approach. We read the literature; consulted psychology, public health, medical, and solution scanning experts; crowd-sourced options using social media; and collated comments on a preprint. Here, we present a list of 519 possible measures to reduce SARS-CoV-2 transmission and spread. We provide a long list of options for policymakers and businesses to consider when designing biosecurity plans to combat SARS-CoV-2 and similar pathogens in the future. We also developed an online application to help with this process. We encourage testing of actions, documentation of outcomes, revisions to the current list, and the addition of further options.</p

Production of e+e−e^+e^- Pairs Accompanied by Nuclear Dissociation in Ultra-Peripheral Heavy Ion Collision

We present the first data on $e^+e^-$ pair production accompanied by nuclear breakup in ultra-peripheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order corrections to the pair production cross section should be enhanced. We compare the pair kinematic distributions with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED); the latter includes the photon virtuality. The cross section, pair mass, rapidity and angular distributions are in good agreement with both calculations. The pair transverse momentum, $p_T$, spectrum agrees with the QED calculation, but not with the equivalent photon approach. We set limits on higher-order contributions to the cross section. The $e^+$ and $e^-$ $p_T$ spectra are similar, with no evidence for interference effects due to higher-order diagrams.Comment: 6 pages with 3 figures Slightly modified version that will appear in Phys. Rev.

Highly unsaturated fatty acid synthesis in marine fish: Cloning, functional characterization, and nutritional regulation of fatty acyl delta6 desaturase of Atlantic cod (Gadus morhua L.)

Fish contain high levels of the n-3 highly unsaturated fatty acids (HUFA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids that are crucial to the health of higher vertebrates. Biosynthesis of HUFA requires enzyme-mediated desaturation of fatty acids. Here we report cloning and functional characterisation of a ∆6 fatty acyl desaturase of Atlantic cod (Gadus morhua), and describe its tissue expression and nutritional regulation. PCR primers were designed based on the sequences of conserved motifs in available fish desaturases and used to isolate a cDNA fragment from liver of cod. The full-length cDNA was obtained by Rapid Amplification of cDNA Ends (RACE). The cDNA for the putative fatty acyl desaturase was shown to comprise 1980bp which included a 5’-UTR of 261bp and a 3’-UTR of 375bp. Sequencing revealed that the cDNA included an ORF of 1344 bp that specified a protein of 447 amino acids. The protein sequence included three histidine boxes, two transmembrane regions, and an N-terminal cytochrome b5 domain containing the haem-binding motif HPGG, all of which are characteristic of microsomal fatty acid desaturases. The cDNA displayed Δ6 desaturase activity in a heterologous yeast expression system. Quantitative real time PCR assay of gene expression in cod showed that the ∆6 desaturase gene, was highly expressed in brain, relatively highly expressed in liver, kidney, intestine, red muscle and gill, and expressed at much lower levels in white muscle, spleen and heart. In contrast, the abundance of a cod fatty acyl elongase transcript was high in brain and gill, with intermediate levels in kidney, spleen, intestine and heart, and relatively low expression in liver. The expression of the Δ6 desaturase gene and the PUFA elongase gene may be under a degree of nutritional regulation, with levels being marginally increased in livers and intestine of fish fed a vegetable oil blend by comparison with levels in fish fed fish oil. However, this was not reflected in increased Δ6 desaturase activity in hepatocytes or enterocytes, which showed very little highly unsaturated fatty acid biosynthesis activity irrespective of diet. The study described has demonstrated that Atlantic cod express a fatty acid desaturase gene with functional Δ6 activity in a yeast expression system. This is consistent with an established hypothesis that the poor ability of marine fish to synthesise HUFA is not due to lack of a Δ6 desaturase, but rather to deficiencies in other parts of the biosynthetic pathway. However, further studies are required to determine why the Δ6 desaturase appears to be barely functional in cod under the conditions tested

The Public Repository of Xenografts enables discovery and randomized phase II-like trials in mice

More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease