Neodymium isotope constraints on provenance, dispersal, and climate-driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years

Marine sediments deposited off the Zambezi River that drains a considerable part of the southeast African continent provide continuous records of the continental climatic and environmental conditions. Here we present time series of neodymium (Nd) isotope signatures of the detrital sediment fraction during the past ~45,000 years, to reconstruct climate-driven changes in the provenance of clays deposited along the Mozambique Margin. Coherent with the surface current regime, the Nd isotope distribution in surface sediments reveals mixing of the alongshore flowing Zambezi suspension load with sediments supplied by smaller rivers located further north. To reconstruct past changes in sediment provenances, Nd isotope signatures of clays that are not significantly fractionated during weathering processes have been obtained from core 64PE304-80, which was recovered just north of the Zambezi mouth at 1329 m water depth. Distinctly unradiogenic clay signatures (ENd values <214.2) are found during the Last Glacial Maximum, Heinrich Stadial 1, and Younger Dryas. In contrast, the Nd isotope record shows higher, more radiogenic isotope signatures during Marine Isotope Stage 3 and between ~15 and ~5 ka BP, the latter coinciding with the timing of the northern hemisphere African Humid Period. The clay-sized sediment fraction with the least radiogenic Nd isotope signatures was deposited during the Holocene, when the adjacent Mozambique Shelf became completely flooded. In general, the contribution of the distinctly unradiogenic Zambezi suspension load has followed the intensity of precession-forced monsoonal precipitation and enhanced during periods of increased southern hemisphere insolation and high-latitude northern hemispheric climate variability

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Simulation of the effects of grain boundary fission gas during thermal transients

This report presents the results of an initial set of out-of-cell transient heating experiments performed on unirradiated UO/sub 2/ pellets fabricated to simulate the effect of grain boundary fission gas on fuel swelling and cladding failure. The fabrication involved trapping high-pressure argon on internal pores by sintering annular UO/sub 2/ pellets in a hot isostatic press (HIP). The pellet stack was subjected to two separate transients (DGF83-03A and -03B). Figures show photomicrographs of HIPped and non-HIPped UO/sub 2/, respectively, and the adjacent cladding after DGF83-03B. Fuel melting occurred at the center of both the HIPped and non-HIPped pellets; however, a dark ring is present near the center in the HIPped fuel but not in the non-HIPped fuel. This dark band is a high-porosity region due to increased grain boundary/edge swelling in that pellet. In contrast, grain boundary/edge swelling did not occur in the non-HIPped pellets. Thus, the presence of the high-pressure argon trapped on internal pores during sintering in the HIP altered the microstructural behavior. Results of these preliminary tests indicate that the microstructural behavior of HIPped fuel during thermal transients is different from the behavior of conventionally fabricated fuel

New evidence for the production of EM-type ocean island basalts and large volumes of volcaniclastites during the early history of the Manihiki Plateau

Alkaline volcanic rocks including nephelinites, basanites and trachybasalts dredged from the volcanic pedestal of Rakahanga Atoll and from a volcanic edifice with 100 satellite volcanoes at the eastern edge of the Manihiki Plateau, ca. 40 km southwest of the atoll, fall well within the category of EM-type ocean island basalts. They indicate a hotspot involvement during the formation of the plateau basement. The rocks are thought to be products of explosive eruptions which took place subaerially or in shallow water in the Aptian. The volcanoes, together with other volcanic eruption centers, most likely were responsible for the formation of the 230 m thick volcaniclastite layer which rests on the basement for at least 5000 km2 of the eastern part of the Manihiki Plateau. Erosion has prevented any substantial sediment cover on the volcanic cone field and most of the slope of Rakahanga and thin pelagic limestones were deposited instead at least since the Maastrichtian

Voxel-Based Morphometry-from Hype to Hope. A Study on Hippocampal Atrophy in Mesial Temporal Lobe Epilepsy

BACKGROUND AND PURPOSE Automated volumetry of the hippocampus is considered useful to assist the diagnosis of hippocampal sclerosis in temporal lobe epilepsy. However, voxel-based morphometry is rarely used for individual subjects because of high rates of false-positives. We investigated whether an approach with high dimensional warping to the template and nonparametric statistics would be useful to detect hippocampal atrophy in patients with hippocampal sclerosis. MATERIALS AND METHODS We performed single-subject voxel-based morphometry with nonparametric statistics within the framework of Statistical Parametric Mapping to compare MRI from 26 well-characterized patients with temporal lobe epilepsy individually against a group of 110 healthy controls. The following statistical threshold was used: P < .05 corrected for multiple comparisons with family-wise error over the region of interest right and left hippocampus. RESULTS The sensitivity for the detection of atrophy related to hippocampal sclerosis was 0.92 (95% CI, 0.67-0.99) for the right hippocampus and 0.60 (0.31-0.83) for the left, and the specificity for volume changes was 0.98 (0.93-0.99). All clusters of decreased hippocampal volumes were correctly lateralized to the seizure focus. Hippocampal volume decrease was in accordance with neuronal cell loss on histology reports. CONCLUSIONS Nonparametric voxel-based morphometry is sensitive and specific for hippocampal atrophy in patients with mesial temporal lobe epilepsy and may be useful in clinical practice

Front-end electro-optical interfaces for CMS HCAL

The CMS experiment is a complex instrument to study particle physics at the energy frontier. An important detector subsystem within CMS is the hadron calorimeter or HCAL, consisting of four subsystems that cover the kinematic region $\beta$ <5. This paper provides details of the electro-optical interfaces for the central barrel subsystem that operates in a region of high magnetic field and converts scintillation signals from megatile sampling layers to lower geometry for energy measurement. (3 refs)

Laser developments and resonance ionization spectroscopy at IGISOL

We present an overview of recent laser ion source developments at the IGISOL facility, Jyväskylä. Technological advances in the lasers have led to a considerable increase in second-harmonic laser power with the use of intra-cavity second-harmonic generation, as well as to narrow linewidth capability by applying an injection-locking technique to a Ti:sapphire laser. The use of a diffraction grating for frequency selection in a new laser resonator has dramatically improved the wide-range tunability of the laser system, resulting in an ideal tool for the development of new ionization schemes. The role of different laser bandwidths, laser intensity and environmental broadening mechanisms on the experimental width of the measured spectral line have been studied using bismuth, silver and nickel, in the gas cell and expanding gas jet. Applications of novel ion guide nozzle design has led to remarkably collimated gas jets which overcome the current limitations in the gas cell-based laser ion source trap (LIST) method. Detailed planning is under way to optimize the new laser laboratory and laser transport path in order to fully exploit the unique opportunities afforded by the new IGISOL-4 facility