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We present a sediment-mixing process model of till genesis based on data from surface tills of the Saginaw lobe terrain in lower Michigan. Our research uses a spatial approach to understanding glacial landsystems and till genesis. We sampled calcareous till at 336 upland sites and at 17 sites in lacustrine sediment of the Saginaw Lake plain. The loamy tills have bimodal grain-size curves, with a fine-texture mode near the silt–clay boundary and a sand mode. Spatial grouping analysis suggests that tills can be divided into six groups, each with different textures and clay mineral compositions that vary systematically down-ice. The similarity among groups with respect to the silt–clay mode and clay mineralogy argues for a common origin for the fines—illite-rich lacustrine sediment of the Saginaw Lake plain. Fine-textured sediments were probably entrained, transported, and deposited down-ice as till, which also becomes sandier and enriched in kaolinite, reflecting increasing mixing with shallow sandstone bedrock with distance from the lacustrine clay source. Clayey tills on the flanks of the Saginaw terrain may reflect proglacial ponding against nearby uplands. A process model of progressive down-ice mixing of preexisting fine lake sediments with crushed/abraded sandstone bedrock helps to better explain till textures compared with a purely crushing/abrasion process model.
Glacier surface mass-balance measurements on Greenland started more than a century ago, but no compilation exists of the observations from the ablation area of the ice sheet and local glaciers. Such data could be used in the evaluation of modelled surface mass balance, or to document changes in glacier melt independently from model output. Here, we present a comprehensive database of Greenland glacier surface mass-balance observations from the ablation area of the ice sheet and local glaciers. The database spans the 123 a from 1892 to 2015, contains a total of ~3000 measurements from 46 sites, and is openly accessible through the PROMICE web portal (http://www.promice.dk). For each measurement we provide X, Y and Z coordinates, starting and ending dates as well as quality flags. We give sources for each entry and for all metadata. Two thirds of the data were collected from grey literature and unpublished archive documents. Roughly 60% of the measurements were performed by the Geological Survey of Denmark and Greenland (GEUS, previously GGU). The data cover all regions of Greenland except for the southernmost part of the east coast, but also emphasize the importance of long-term time series of which there are only two exceeding 20 a. We use the data to analyse uncertainties in point measurements of surface mass balance, as well as to estimate surface mass-balance profiles for most regions of Greenland.
We present a preliminary analysis of the self-absorbed [CII]-spectra observed with SOFIA/GREAT towards NGC 2024. Together with the detected [13CII] hyperfine satellites, the observed spectra require surprisingly high column densities of C+, both in the warm core and the foreground absorption component. Such high column densities are a challenge to explain with present state-of-the-art PDR models of the UV/molecular cloud interaction.
It is shown that various spectroscopic methods based on measurements of X-ray spectra radiated from cluster targets can be used for estimation of the destruction degree of clusters by laser prepulses. These methods allow insight to be gained regarding the important issue of preservation of the dense cluster core at the moment of the arrival of the main laser pulse. In addition, they can be used for quantitative estimation of the size of the undestroyed parts of the clusters and also for measuring the temperature and density of the preplasmas produced by the laser prepulses.
We report spectrophotometric observations made with SOFIA/FORCAST on 2011 June 2 UT. Optical measurements have previously shown that the abundance discrepancy factor (adf) varies with position in several high-adf PNe, and is highest close to the central star. The very low electron temperature inclusions postulated to explain the abundance discrepancy, must be cooled predominantly by fine structure IR lines. These SOFIA data will map mid-IR FS lines (and our related Herschel program will add several far-IR FS lines) in the bright, well-characterized, high-adf PN NGC 7009. We will compare these IR results with FS optical line measurements in order to correlate ratios of IR to optical fluxes with position, and thus correlate with where the adf peaks.
We observed several H ii regions in the dwarf irregular galaxy NGC 6822 using the infrared spectrograph on the Spitzer Space Telescope. Our aim is twofold: first, to examine the neon to sulfur abundance ratio in order to determine how much it may vary and whether or not, it is fairly ‘universal’; second, to discriminate and test the predicted ionizing spectral energy distribution between various stellar atmosphere models by comparing with our derivation of the ratio of fractional ionizations involving neon and sulfur. This work extends our previous similar studies of H ii regions in M83 and M33 to lower metallicities.
The effect of the P-M system of hybrid dysgenesis in Drosophila melanogaster on unequal crossing-over was studied using the Bar duplication. This system of dysgenesis had no demonstrable effect on the rate of Bar reversion. In the course of the study it was found that there was a greatly reduced rate of reversion in two homozygous inversion stocks. Further, one revertant was found which may result from unequal crossing over at the Bar locus in males.
The ARGOS Food and Dose Module has been adopted by the RPII to simulate the transfer of radioactivity in the food chain in the event of a large scale nuclear incident and to enhance its capability to assess the radiological consequences. This paper describes adaptation of this model for Irish conditions and its intended use, illustrated with examples from a recent national emergency exercise. By enabling time series of activity concentrations of individual radionuclide or radionuclide groups in a range of food and animal feeds and comparison with appropriate action levels, the model would assist the formulation of early advice regarding countermeasures and would be an important factor in refining a pre-defined sampling strategy. The current implementation provides a basis for more detailed modelling which would inevitably be required in the event of a real incident. As the situation evolved and monitoring results became available, FDM could be refined and used to predict future concentrations or those over a wide spatial area with increased confidence.
An investigation is made of the role of hollow atoms in the spectra of an ultrashort-pulse-laser-driven Ar cluster target. Experimental measurements are presented from an Ar cluster-gas target using short-pulse lasers with various intensities, durations, and contrasts. Calculations in support of these measurements have been performed using a detailed atomic kinetics model with the ion distributions found from solution of the time-dependent rate equations. The calculations are in good agreement with the measurements and the role of hollow atoms in the resulting complicated spectra is analyzed. It is demonstrated that, although the presence of hollow atoms is estimated to add only around 2% to the total line emission, signatures of hollow atom spectra can be identified in the calculations, which are qualitatively supported by the experimental measurements.
The Radiological Protection Institute of Ireland (RPII) monitors airborne radioactivity concentrations at ten stations throughout Ireland, of which nine are equipped with low volume particulate samplers and one, in Dublin, with a high volume particulate sampler. The low volume particulate samples are assessed for total beta activity. In the period 1998-2003 the total beta activity concentrations observed have been consistently low, ranging between 0.03 and 1.33 mBq m-3 with a mean over all sampling sites of 0.26 ± 0.15 mBq m-3 (n = 2361). High volume particulate samples have been assessed for caesium-137 and beryllium-7. A mean caesium-137 activity concentration of 2.3 ± 2.2 mBq m-3 (n = 26) was observed in samples taken since 1993 while the mean beryllium-7 activity concentration over this period was 3.0 ± 1.6 mBq m-3 (n = 42).
In addition, air sampled at the RPII's laboratory in Dublin, is monitored for krypton-85, a radioactive noble gas, released into the environment primarily as a result of the reprocessing of nuclear fuel at installations such as Sellafield in the UK and Cogema La Hague in France. Analysis of the krypton-85 monitoring data, along with additional backward air trajectory modelling, demonstrate the influence of the reprocessing plants on the krypton-85 concentrations in Ireland.
The integration of molecular and morphological approaches has produced substantial progress in understanding the higher classification of most major invertebrate groups. The striking exception to this is the Polychaeta. Neither the membership nor the higher classification of this group has been robustly established. Major inconsistencies exist between the only comprehensive cladistic analysis of Polychaeta using morphological data and the DNA sequence studies covering all or part of the taxon.
We have compiled a dataset of available nearly complete 18S ribosomal DNA sequences and collected an additional 22 sequences (20 Polychaeta in 19 taxa, one Myzostomida and one Phoronida) to obtain more comprehensive coverage of polychaete diversity for this gene. Analyses of the data do not resolve all inconsistencies among current hypotheses of polychaete phylogeny. They do support the recognition (in whole or part) of some clades such as the Eunicida, Phyllodocida and Terebellida that have been proposed on morphological grounds. Our analyses contradict the Canalipalpata and the Scolecida. Although the polychaete sister-group to the Clitellata is not clearly resolved in our analyses, the clitellates are always recovered as a derived clade within the Polychaeta. Increased taxon sampling is required to elucidate further the phylogeny of the Polychaeta.
A non-lithographic method of fabricating high-density arrays of nanometer-scale vertical columns was investigated. The use of oblique deposition techniques allows the fabrication of isolated vertical columns in a single-step evaporation process without the need for either pre- or post-deposition lithographic processing. Extreme oblique incidence deposition with computer controlled substrate motion was utilized to fabricate columns with diameters near 100 nm and densities exceeding 109 columns/cm2. The desired column geometry may be engineered through choice of deposition angle and substrate spin rate. In one potential application of these microstructures, arrays of vertical columns were fabricated from silicon and carbon and tested for field emission characteristics. Further studies were made on the use of ion milling to modify the tips of the nanocolumns in order to improve the field emission properties.
Amorphous silicon based thin film transistor liquid crystal displays (TFT/LCD) have become the dominant technology used for flat panel displays for notebook computers. The need for higher resolution, larger diagonal displays for both notebook and desktop applications is discussed. Calculations have shown that the use of high conductivity gate metal such as aluminum or copper, together with the implementation of improved groundrules, can significantly extend today's technology. Aluminum suffers from problems with hillock formation during PECVD processing, and copper typically has poor adhesion to glass, reaction problems with silicon and other PECVD films, and difficulties in contacting it to other metals. Approaches to solving problems with both materials are presented, and a novel reduced mask process to fabricate high resolution, high aperture ratio 10.5” SXGA (1280×1024) displays is described. The process uses copper gate metallurgy with redundancy, without the need for extra processing steps. The resulting displays have 150 dpi color resolution, an aperture ratio of over 35%, and excellent image quality, making them the first high resolution displays that are suitable for notebook applications.
Amorphous silicon based thin film transistor liquid crystal displays (TFT/LCD) have become the dominant technology used for flat panel displays for notebook computers. The need for higher resolution, larger diagonal displays for both notebook and desktop applications is discussed. Calculations have shown that the use of high conductivity gate metal such as aluminum or copper, together with the implementation of improved groundrules, can significantly extend today's technology. Aluminum suffers from problems with hillock formation during PECVD processing, and copper typically has poor adhesion to glass, reaction problems with silicon and other PECVD films, and difficulties in contacting it to other metals. Approaches to solving problems with both materials are presented, and a novel reduced mask process to fabricate high resolution, high aperture ratio 10.5” SXGA (1280 × 1024) displays is described. The process uses copper gate metallurgy with redundancy, without the need for extra processing steps. The resulting displays have 150 dpi color resolution, an aperture ratio of over 35%, and excellent image quality, making them the first high resolution displays that are suitable for notebook applications.
Background. Evidence suggests that schizophrenia may be
disorder with origins in early
intrauterine mal-development. We have constructed a comprehensive
anthropometric scale for the
evaluation of dysmorphic features as an index of the nature and timing
Method. A detailed set of craniofacial and bodily measures
compiled and applied to 174
patients with schizophrenia and 80 matched control subjects.
Results. Patients had significantly higher scores on this
scale and displayed multiple anomalies of
the craniofacial region with an overall narrowing and elongation of the
mid-face and lower face.
Twelve craniofacial anomalies independently distinguished patients from
controls and these
variables correctly classified 95% of patients and 80% of control subjects.
Conclusions. This new scale, while procedurally more exacting
than the Waldrop scale, more clearly
defines the topography of anomalies previously suspected in individuals
with schizophrenia. These
findings constitute direct evidence for disturbed craniofacial development
in schizophrenia and
indicate origins in the foetal period during which the characteristic human
facial pattern evolves in
close association with brain differentiation.
We present new far-infrared line observations of the planetary nebulae (PNs) NGC 7027, NGC 7009, NGC 6210, NGC 6543, and IC 4997 obtained with the Kuiper Airborne Observatory (KAO). The bulk of our data are for NGC 7027 and NGC 7009, including [Ne V] 24 μm, [O IV] 26 μm, [O III] (52, 88μm), and [Nm] 57 μm. Our data for [O III] (52, 88) and [N III] 57 in NGC 7027 represent the first measurements of these lines in this source. The large [O III] 52/88 flux ratio implies an electron density (cm–3) of log Ne[O III] = 4.19, the largest Ne ever inferred from these lines. We derive N++/O++ = 0.394±0.062 for NGC 7027 and 0.179±0.043 for NGC 6210. We are able to infer the O+3/O++ ionic ratio from our data. As gauged by this ionic ratio, NGC 7027 is substantially higher ionization than is NGC 7009 – consistent with our observation that the former produces copious [Ne V] emission while the latter does not. These data help characterize the stellar ionizing radiation field.