1,092 research outputs found
Oxygen and silicon stable isotopes of diatom silica: reconstructing changes in surface water hydrography and silicic acid utilization in the late Pleistocene subarctic Pacific.
No full textDeglacial variations in upper ocean nutrient dynamics and stratification in high latitudes, as well as associated changes in thermohaline overturning circulation, are thought to have played a key role in changing atmospheric CO2 concentrations. This thesis examines the relationship between past changes in subarctic Pacific upper ocean stratification and nutrient (silicic acid) utilization, using oxygen and silicon stable isotopes of diatom silica, for the first time at millennial-scale resolution and analyzed with a new and efficient instrumentation set-up. The isotopic data, presented in three manuscripts, show a consistent picture of millennial-scale variability in upper ocean stratification and silicic acid utilization during the last ~50 ka BP, e.g. indicating that the subarctic Pacific was a source region for atmospheric CO2 during the last deglaciation (late Heinrich Stadial 1 and the Bølling/Allerød). The presented results demonstrate the high potential of combined diatom oxygen and silicon stable isotope analysis especially for, but not restricted to, marine regions characterized by a low biogenic carbonate content like the subarctic Pacific and the Southern Ocean
Edith Cooper’s Sin: Mapping the Willful Bodies of Michael Field
No full textScandal has long been associated with the collaborative partnership of Michael Field (the pseudonym/collaborative identity of Katharine Harris Bradley and Edith Emma Cooper): In the 1880s, the English literary world was reportedly scandalized to discover the recently lionized young debut writer, Michael Field, was actually an aunt and niece from suburban Bristol. Rediscovered in the 1990s as lesbian lovers and writers, Bradley and Cooper re-emerged at the forefront of historiography on transgressive sexuality and the nature of female same-sex relationships, and current scholarship has extended this to argue this relationship embraced more complex and fluidly desiring bodies. If LGBTQ+ sexuality is no longer a site of scandal, nevertheless under the surface a modern discomfort with the spectre of aunt-niece incest remains. In some sense, “Michael Field” often represents the bellwether for scholarship on Victorian women writers. Using Sara Ahmed’s theory of wilfullness and digital humanities scholarship on The Diaries of Michael Field this chapter draws on Bickle’s transcription of the 1912 diary, written predominantly by Edith Cooper whilst dying of cancer. This volume, which begins with Cooper’s discussion of her sin in the context of her Catholic conversion and includes a tumultuous penultimate meeting with art historian Bernhard Berenson—central to several of Cooper’s love triangles—grants a unique vision into Cooper’s sense of her own sexuality, and how she viewed the morality of her most intimate relationships
Paleoceanography of sediment cores SO202-27-6 during MIS 3
No full textThe modern subarctic Pacific is characterized by a steep salinity-driven surface water stratification, which hampers the supply of saline and nutrient-rich deeper waters into the euphotic zone, limiting productivity. However, the strength of the halocline might have varied in the past. Here, we present diatom oxygen (d18Odiat) and silicon (d30Sidiat) stable isotope data from the open subarctic North-East (NE) Pacific (SO202-27-6; Gulf of Alaska), in combination with other proxy data (Neogloboquadrina pachydermasin d18O, biogenic opal, Ca and Fe intensities, IRD), to evaluate changes in surface water hydrography and productivity during Marine Isotope Stage (MIS) 3, characterized by millennial-scale temperature changes (Dansgaard-Oeschger (D-O) cycles) documented in Greenland ice cores
(Table S1) Oxygen and silicon stable isotopes of diatom silica of sediment core SO202-27-6 during MIS 3
No full textElectronic spectroscopy of carbon chain radicals using cw cavity ring down in conjunction with mass detection
No full textThe electronic absorption spectrum of the 2A'' − X 2A'' origin band of the
nonlinear carbon chain radical C6H4
+ was rotationally resolved by cw-CRD
spectroscopy [41]. It was analysed using a least-squares method and the rotational
constants of the ground and excited states were determined accurately. The 581 nm
band observed under the same discharge conditions is assigned to the same electronic
transition of C6H4
+ but involving the excitation of the ν12 vibrational mode in the
upper state based on comparison with ab initio results. The presented data provide a
basis for future observations of the C6H4
+ radical in both millimeter and infrared
regions.
A linear time-of-flight mass spectrometer was constructed to provide on-line
monitoring of the plasma discharge with a mass resolution of 1 amu at a range up to
120 amu. The results from the acetylene/helium plasma discharge are in good
agreement with those obtained using the reflectron TOF mass spectrometer and a
similar ion source [42]. To improve the experimental set-up, the following
modifications can be made:
• Transferring the signal from the oscilloscope directly to a PC via a
GPIB card will increase the speed of data processing;
• Computer control of the voltage applied will make the spectrometer
easier to operate;
• Using a metal grid at ground potential in front of MCP detector will
increase the flight time of ions improving the mass resolution;
• Installing a focusing lens will increase the number of ions arriving at
the detector, and therefore increase the signal on the oscilloscope
(Table S2) Composition of pre-sonicated diatom samples of sediment core SO202-27-6 during MIS 3
No full text(Table 1) Planktic (N. pachyderma sin) radiocarbon ages and calibrated ages of sediment core SO202-27-6 during MIS 3
No full text(Table S3) Contamination of purified diatom samples with non-biogenic silicates estimated from SiO2 and Al2O3 percentages determined by EDS of sediment core SO202-27-6 during MIS 3
No full text(Table S3) Contamination of purified diatom samples with non-biogenic silicates estimated from SiO2 and Al2O3 percentages determined by ICP-OES of sediment core SO202-27-6 during MIS 3
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