Late Pleistocene climate change and landscape dynamics in the Eastern Alps: the inner-alpine Unterangerberg record (Austria)

Drill cores from the inner-alpine valley terrace of Unterangerberg, located in the Eastern Alps of Austria, offer first insights into a Pleistocene sedimentary record that was not accessible so far. The succession comprises diamict, gravel, sand, lignite and thick, fine grained sediments. Additionally, cataclastic deposits originating from two paleo-landslide events are present. Multi-proxy analyses including sedimentological and palynological investigations as well as radiocarbon and luminescence data record the onset of the last glacial period (Wurmian) at Unterangerberg at similar to 120-110 ka. This first time period, correlated to the MIS 5d, was characterised by strong fluvial aggradation under cold climatic conditions, with only sparse vegetation cover. Furthermore, two large and quasi-synchronous landslide events occurred during this time interval. No record of the first Early Wiirmian interstadial (MIS 5c) is preserved. During the second Early Wiirmian interstadial (MIS 5a), the local vegetation was characterised by a boreal forest dominated by Picea, with few thermophilous elements. The subsequent collapse of the vegetation is recorded by sediments dated to similar to 70-60 ka (i.e. MIS 4), with very low pollen concentrations and the potential presence of permafrost. Climatic conditions improved again between similar to 55 and 45 ka (MIS 3) and cold-adapted trees re-appeared during interstadials, forming an open forest vegetation. MIS 3 stadials were shorter and less severe than the MIS 4 at Unterangerberg, and vegetation during these cold phases was mainly composed of shrubs, herbs and grasses, similar to what is known from today's alpine timberline. The Unterangerberg record ended at similar to 45 ka and/or was truncated by ice during the Last Glacial Maximum. (C) 2013 Elsevier Ltd. All rights reserved.

Late-Pleistocene palaeoclimate and glacial activity recorded from lake sediments in the Eastern Alps

Greenland ice core data show that the last glaciation in the Northern Hemisphere was characterized by relatively short and rapid warming-cooling cycles. While the Last Glacial Maximum (LGM) and the following Late Glacial are well documented in the Eastern Alps, continuous and well dated records of the time period preceding the LGM are only known from stalagmites. Although most of the sediment that filled the Alpine valleys prior to the LGM was eroded, thick successions have been locally preserved as terraces along the flanks of large longitudinal valleys. The Inn valley in Tyrol (Austria) offers the most striking examples of Pleistocene terraces in the Eastern Alps. A large number of drill cores provides the opportunity to study these sediments for the first time in great detail. Our study focuses on the river terrace of Unterangerberg near Wörgl, where LGM gravel and till were deposited on top of (glacio)lacustrine sediments. The cores comprise mostly silty material, ranging from organic-rich to organic-poor and dropstone-rich beds. A diamictic layer classified as basal till is present at the bottom of the lake sediments. Radiocarbon ages of plant macro remains from the lake sequences indicate deposition between ~40 and >50 cal. ka BP. Luminescence ages obtained from fine-grain polymineral (4-11 μm) samples suggest an age of the lake deposits between ~40 to 60 ka and are consistent with the radiocarbon dates. Sedimentological analyses indicate that sedimentation in these palaeolakes was driven by local processes, but also by climatically induced changes in nearby glacier activity. These observations strongly hint towards a significant ice advance in the Eastern Alps during the early last glacial and subsequent mild interstadial conditions, supporting a local coniferous forest vegetation.

The Physical and Chemical Structure of Hot Molecular Cores

We have made self-consistent models of the density and temperature profiles of the gas and dust surrounding embedded luminous objects using a detailed radiative transfer model together with observations of the spectral energy distribution of hot molecular cores. Using these profiles we have investigated the hot core chemistry which results when grain mantles are evaporated, taking into account the different binding energies of the mantle molecules, as well a model in which we assume that all molecules are embedded in water ice and have a common binding energy. We find that most of the resulting column densities are consistent with those observed toward the hot core G34.3+0.15 at a time around 10^4 years after central luminous star formation. We have also investigated the dependence of the chemical structure on the density profile which suggests an observational possibility of constraining density profiles from determination of the source sizes of line emission from desorbed molecules.

Enhanced Deuterium Fractionation in Dense Interstellar Cores Resulting from Multiply Deuterated H3+

In this Letter, we present the first results from updated models of interstellar deuterium chemistry that now include all possible deuterated isotopomers of H3+. We find that in regions of high density and heavy depletion, such as prestellar cores, the inclusion of HD2+ and D3+ enhances the fractionation of ionic and neutral species significantly. Our models are the first to predict the very high atomic D/H ratios (>=0.3) necessary for grain-surface chemistry models to reproduce the high formaldehyde and methanol fractionation seen in star-forming regions.

Physicochemical and mineralogical characteristics of soil/saprolite cores from a field research site, Tennessee

Site characterization is an essential initial step in determining the feasibility of remedial alternatives at hazardous waste sites. Physicochemical and mineralogical characterization of U-contaminated soils in deeply weathered saprolite at Area 2 of the DOE Field Research Center (FRC) site, Oak Ridge, TN, was accomplished to examine the feasibility of bioremediation. Concentrations of U in soil–saprolite (up to 291 mg kg–1 in oxalate-extractable Uo) were closely related to low pH (ca. 4–5), high effective cation exchange capacity without Ca (64.7–83.2 cmolc kg–1), amorphous Mn content (up to 9910 mg kg–1), and the decreased presence of relative clay mineral contents in the bulk samples (i.e., illite 2.5–12 wt. %, average 32 wt. %). The pH of the fill material ranged from 7.0 to 10.5, whereas the pH of the saprolite ranged from 4.5 to 8. Uranium concentration was highest (about 300 mg kg–1) at around 6 m below land surface near the saprolite–fill interface. The pH of ground water at Area 2 tended to be between 6 and 7 with U concentrations of about 0.9 to 1.7 mg L–1. These site specific characteristics of Area 2, which has lower U and nitrate contamination levels and more neutral ground water pH compared with FRC Areas 1 and 3 (ca. 5.5 and

Reuseable Silicon IP Cores for Discrete Wavelet Transform Applications

Architectures and methods for the rapid design of silicon cores for implementing discrete wavelet transforms over a wide range of specifications are described. These architectures are efficient, modular, scalable, and cover orthonormal and biorthogonal wavelet transform families. They offer efficient hardware utilization by exploiting a number of core wavelet filter properties and allow the creation of silicon designs that are highly parameterized, including in terms of wavelet type and wordlengths. Control circuitry is embedded within these systems allowing them to be cascaded for any desired level of decomposition without any interface glue logic. The time to produce chip designs for a specific wavelet application is typically less than a day and these are comparable in area and performance to handcrafted designs. They are also portable across a wide range of silicon foundries and suitable for field programmable gate array and programmable logic data implementation. The approach described has also been extended to wavelet packet transforms.

Generic Architecture and Semiconductor Intellectual Property Cores for Avanced Encryption Standard Cryptography

A generic architecture for implementing the advanced encryption standard (AES) encryption algorithm in silicon is proposed. This allows the instantiation of a wide range of chip specifications, with these taking the form of semiconductor intellectual property (IP) cores. Cores implemented from this architecture can perform both encryption and decryption and support four modes of operation: (i) electronic codebook mode; (ii) output feedback mode; (iii) cipher block chaining mode; and (iv) ciphertext feedback mode. Chip designs can also be generated to cover all three AES key lengths, namely 128 bits, 192 bits and 256 bits. On-the-fly generation of the round keys required during decryption is also possible. The general, flexible and multi-functional nature of the approach described contrasts with previous designs which, to date, have been focused on specific implementations. The presented ideas are demonstrated by implementation in FPGA technology. However, the architecture and IP cores derived from this are easily migratable to other silicon technologies including ASIC and PLD and are capable of covering a wide range of modem communication systems cryptographic requirements. Moreover, the designs produced have a gate count and throughput comparable with or better than the previous one-off solutions.

A survey of [ D2CO] /[ H2CO] and [ N2D^+] /[ N2H^+] ratios towards protostellar cores

Aims.We use observations and models of molecular D/H ratios to probe the physical conditions and chemical history of the gas and to differentiate between gas-phase and grain-surface chemical processing in star forming regions. Methods: As a follow up to previous observations of HDCO/H2CO and DCN/HCN ratios in a selection of low-mass protostellar cores, we have measured D2CO/H2CO and N2D^+/N2H+ ratios in these same sources. For comparison, we have also measured N2D^+/N2H+ ratios towards several starless cores and have searched for N2D+ and deuterated formaldehyde towards hot molecular cores (HMCs) associated with high mass star formation. We compare our results with predictions from detailed chemical models, and to other observations made in these sources. Results: Towards the starless cores and low-mass protostellar sources we have found very high N2D+ fractionation, which suggests that the bulk of the gas in these regions is cold and heavily depleted. The non-detections of N2D+ in the HMCs indicate higher temperatures. We did detect HDCO towards two of the HMCs, with abundances 1-3% of H2CO. These are the first detections of deuterated formaldehyde in high mass sources since Turner (1990) measured HDCO/H2CO and D2CO/H2CO towards the Orion Compact Ridge. Figures 1-5 are only available in electronic form at http://www.aanda.org

Design of silicon IP cores for biorthogonal wavelet transforms

A methodology for rapid silicon design of biorthogonal wavelet transform systems has been developed. This is based on generic, scalable architectures for the forward and inverse wavelet filters. These architectures offer efficient hardware utilisation by combining the linear phase property of biorthogonal filters with decimation and interpolation. The resulting designs have been parameterised in terms of types of wavelet and wordlengths for data and coefficients. Control circuitry is embedded within these cores that allows them to be cascaded for any desired level of decomposition without any interface logic. The time to produce silicon designs for a biorthogonal wavelet system is only the time required to run synthesis and layout tools with no further design effort required. The resulting silicon cores produced are comparable in area and performance to hand-crafted designs. These designs are also portable across a range of foundries and are suitable for FPGA and PLD implementations.