558 research outputs found
Persistent global marine euxinia in the early Silurian
No full textThe second pulse of the Late Ordovician mass extinction occurred around the Hirnantian-Rhuddanian boundary (~444 Ma) and has been correlated with expanded marine anoxia lasting into the earliest Silurian. Characterization of the Hirnantian ocean anoxic event has focused on the onset of anoxia, with global reconstructions based on carbonate δ238U modeling. However, there have been limited attempts to quantify uncertainty in metal isotope mass balance approaches. Here, we probabilistically evaluate coupled metal isotopes and sedimentary archives to increase constraint. We present iron speciation, metal concentration, δ98Mo and δ238U measurements of Rhuddanian black shales from the Murzuq Basin, Libya. We evaluate these data (and published carbonate δ238U data) with a coupled stochastic mass balance model. Combined statistical analysis of metal isotopes and sedimentary sinks provides uncertainty-bounded constraints on the intensity of Hirnantian-Rhuddanian euxinia. This work extends the duration of anoxia to >3 Myrs – notably longer than well-studied Mesozoic ocean anoxic events
Bracketing off population does not advance ethical reflection on EVCs: A reply to Kayser and Schneider
No full textIn a recent contribution to this journal, Kayser and Schneider reviewed the relevance of external visible characteristics (EVCs) for criminal investigation [1]. Their aim was to broaden the debate about the scientific, legal, and ethical dimensions of the use of EVCs for criminal investigation, which will help to achieve a firm legal basis for the application of EVCs eventually. While we applaud Kayser's and Schneider's overall very thoughtful and nuanced discussion of this topic, we were surprised to read that they suggest that a discussion of ‘the challenges of using problematic definitions of populations […] has to be kept separate from using EVCs’ (p. 158). In contrast to these authors, we contend that questions about defining populations – both at the level of scientific research, and the application of EVCs in criminal investigation – lie at the core of most social, ethical, and legal issues raised by the translation of EVCs into forensic and police practice
Data and Code for Atmospheric oxygen abundance, marine nutrient availability, and organic carbon fluxes to the seafloor
No full textCode and Data for manuscript "Atmospheric oxygen abundance, marine nutrient availability, and organic carbon fluxes to the seafloor
Music and elite identity in the English country house, c.1790-1840
No full textIn this thesis I investigate two untapped music book collections that belonged to two women. Elizabeth Sykes Egerton (1777-1853) and Lydia Hoare Acland (1786-1856) lived at Tatton Park, Cheshire, and Killerton House, Devon, respectively. Upon their marriage in the early nineteenth century, they brought with them the music books they had compiled so far to their new homes, and they continued to collect and play music after marriage. I examine the vocal music in Elizabeth’s and Lydia’s collections, and I aim to show how selected vocal music repertoires contributed toward the construction of landed elite identity in these women and their husbands, concentrating on gender, class, national identity and religion.In chapter one, I concentrate on songs that depict destitute and suffering individuals to move both listeners and performers to compassion. The songs are topical and provide insights into contemporary understandings of sympathy and landed elite responsibility for the distressed. In chapter two, I focus on the ingoing and outgoing movements of music in the country house, and the consumption of foreign music in the home. I divide the chapter into two sections, first examining Elizabeth’s Italian vocal music that she collected during her girlhood years in London and York in the 1790s. The Italian music that Elizabeth brought to Tatton complemented other Italian objects and items in the home. Italian culture appealed to the Egerton family both before and after Elizabeth and Wilbraham married. In the second section, I investigate Lydia and her family’s journey to Vienna for the Congress in 1814-1815. Lydia took away with her a book of vocal music to remind her of home in a foreign environment. While away in Vienna, the Aclands attended concerts and music salons, and they purchased music books to bring back home to add to their collection. In the final chapter, I concentrate on the man of the house at music and I consider the social expectations, duties and responsibilities that had befallen our landed elite men, Thomas Dyke Acland and Wilbraham Egerton. I discuss Thomas’s and Wilbraham’s musical engagements and occasions for performing music, and how men’s music-making contributed to a masculine identity.By placing the vocal music in broader social and cultural contexts, reading personal correspondence, newspaper articles, account books and diaries, we can begin to understand what our families thought about music, and how they used and experienced music in and around their homes, forming an important part of their lifestyle
Multiple tandem splicing silencer elements suppress aberrant splicing within the long exon 26 of the human Apolipoprotein B gene.
No full textABSTRACT: BACKGROUND: Apolipoprotein B (APOB) is an integral component of the chylomicron and the atherogenic lipoproteins LDL and Lp(a). Exon 26 of the APOB pre-mRNA is unusually long at 7,572 nt and is constitutively spliced. It is also subject to RNA editing in the intestine, which generates a shortened isoform, APOB48, assembled exclusively into chylomicrons. Due to its length, exon 26 contains multiple pseudo splice sites which are not spliced, but which conform to the degenerate splice site consensus. RESULTS: We demonstrate that these pseudo splice sites are repressed by multiple, tandem splicing silencers distributed along the length of exon 26. The distribution of these elements appears to be heterogeneous, with a greater frequency in the middle 4,800 nt of the exon. CONCLUSION: Repression of these splice sites is key to maintaining the integrity of exon 26 during RNA splicing and therefore the correct expression of both isoforms of APOB
Multi-technique surface geophysical surveys over Devon Ice Cap, Canadian Arctic
No full textThis dataset was acquired during a multi-technique surface geophysical campaign in May 2022 over Devon Ice Cap, Canadian Arctic.
Description of data:
Seismic
9 km of active source seismic reflection data
raw segy files for line A and line B
seismic observation log
matlab script for plotting a raw stack of line A and line B
coordinates of each seismic spread, with the ice surface elevation and estimated bed elevation
Transient electromagnetic (TEM)
7 large loop TEM soundings
with 500 x 500 m loop with receiver 250 m outside the loop (away from the transmitter)
USF files for each sounding
coordinates for each TEM sounding
TEM observation log
Magnetotelluric (MT)
17 MT stations
raw, unprocessed EDI files
coordinates for each MT station
MT observation log
Time series data (~80GB) can be found at:
https://drive.google.com/drive/folders/1OyCIP_B3VUJ4-ULSp8YOAPuNEMHuNcN-?usp=share_link
Acknowledgments
We thanks the Polar Continental Shelf Program for logistical support throughout the field season; Rob Harris at Geonics for his support and help with the TEM method; Zoe Vestrum at the University of Alberta for her MT support during deployment to the field;
Funding
This work was funded by the Weston Family Foundation. The aircraft hours were funded by the Polar Continental Survey Program (PCSP) and ArcticNet. MT survey was supported by a NSERC Discovery Grant to Martyn Unsworth and the Future Energy Systems program at the University of Alberta.
Corresponding Author
Siobhan Killingbeck [email protected]
Follicular Dendritic Cells (FDCs) and Sparing of CD4+ T cells from HIV/CD62L Triggered Apoptosis
No full textBoth B and T lymphocytes intimately interact with follicular dendritic cells (FDCs) in lymphoid follicles of secondary lymphoid tissue (e.g., spleen, lymph node, and tonsils). FDCs trap and retain antigens needed to induce and maintain potent memory antibody responses. FDCs contribute both antigen dependent and independent signals to B lymphocytes residing in the microenviroment of germinal centers in secondary lymphoid tissue, which contributes to the optimal activation of these cells as well as T lymphocytes. One important contribution of FDCs to B lymphocytes is signaling that spares these cells from programmed cell death. As B cells differentiate in germinal centers, they begin to mutate the gene segments encoding their antigen receptors. Some of these mutations result in a lowering of the affinity of the receptor for antigen while others leave the affinity unchanged. Importantly, some mutations result in higher affinity interactions between the receptor and antigen. Since antigen specific B cells are important for the ability of the immune system to mount an effective humoral response (antibodies), there needs to be a means for selecting mutations that create high affinity antibodies. This is thought to be accomplished by programming all germinal center B cells to undergo apoptosis unless provided with a rescue signal. The FDC provides the rescue signal and cells are selected based upon their ability to compete for limiting amounts of specific antigen present on FDCs. Those with the highest affinity receptor interact with antigen bearing FDCs and acquire signaling that spares them from apoptosis
A new estimate of detrital redox-sensitive metal concentrations and variability in fluxes to marine sediments
No full textThe enrichment and depletion of redox sensitive trace metals in marine sediments have been used extensively as paleoredox proxies. The trace metals in shale are comprised of both detrital (transported or particulate) and authigenic (precipitated, redox-driven) constituents, potentially complicating the use of this suite of proxies. Untangling the influence of these components is vital for the interpretation of enrichments, depletions, and isotopic signals of iron (Fe), chromium (Cr), uranium (U), and vanadium (V) observed in the rock record. Traditionally, a single crustal average is used as a cutoff for detrital input, and concentrations above or below this value are interpreted as redox derived authigenic enrichment or depletion, while authigenic isotopic signals are frequently corrected for an assumed detrital contribution. Building from an extensive study of soils across the continental United States – which upon transport will become marine sediments – and their elemental concentrations, we find large deviations from accepted crustal averages in redox-sensitive metals (Fe, Cr, U, V) compared to typical detrital tracers (Al, Ti, Sc, Th) and provide new estimates for detrital contributions to the ocean. The variability in these elemental ratios is present over large areas, comparable to the catchment-size of major rivers around the globe. This heterogeneity in detrital flux highlights the need for a reevaluation of how the detrital contribution is assessed in trace metal studies, and the use of confidence intervals rather than single average values, especially in local studies or in the case of small authigenic enrichments
Drone derived orthomosaic and digital surface model of the western Bailey Peninsula 16th February 2022
No full textProgress Code: completedStatement: High quality photogrammetry and geo-positioning, though snow cover obscures many ground features.<b>Purpose</b><br/>Mapping of ice free ground on the Bailey Peninsula for environmental values and background information.Orthomosaic and Digital Surface Model of the western portion of the Bailey Peninsula, Windmill Islands. The orthomosaic was compiled from 1,387 images processed in ESRI SiteScan running Pix4Denginge SDK version 5.0.45.<br/><br/>Drone piloted by Dr Rebecca McWatters with Devon Hamley and Kasey Williams as observers and ground crew. Mission planned and data processed by Dr Dan Wilkins.<br/><br/>Note that much of the normally exposed rock is covered by recent snowfall
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The transfer of heavy metals through trophic levels and their toxicity effects on organisms including humans
No full textThis research has investigated a number of topics pertaining to the effects of metalliferous mining. The combination of these has shown that past mining activities and their resultant waste have led to the accumulation of metals through trophic levels. During visits to Blanchdown Wood, Devon, UK and Snailbeach, Shropshire, UK, samples were collected to examine the effects of the spoil tips on the surrounding ecosystem. Samples of vegetation, soil and animal materials were extracted and analysed by inductively coupled plasma-optical emission spectrometry for the presence of heavy metals and were found to contain varying concentrations of lead, copper, arsenic, tin, tungsten and zinc. Laboratory investigations followed to determine the toxicity effects of lead, copper, and tungsten on Pandorina morum. This demonstrated that although single elements have effects on population growth, a combination of the three cations had pronounced and cumulative effects. It was found that the algae reduced the concentration of lead in the nutrient media, but it was not possible to determine whether lead was accumulated by the algae or adhered to the surface of the cells. In either case it is hypothesized that lead could then be transferred to the succeeding trophic levels. Further samples examined included archaeological finds, such as Anglo-Saxon human skeletons from a non-mining area. The concentrations of lead in these samples indicated that the population had been exposed to lead, and this is further explored. Since the population resided in a non-mining area, it is suggested that the contaminant was ingested via trophic level inputs; thus, providing further evidence certain metals are available to be transferred through the trophic levels to be stored in the human skeleton
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