Space shuttle electromagnetic environment experiment. Phase A: Definition study

Methods for carrying out measurements of earth electromagnetic environment using the space shuttle as a measurement system platform are herein reported. The goal is to provide means for mapping intentional and nonintentional emitters on earth in the frequency range 0.4 to 40 GHz. A survey was made of known emitters using available data from national and international regulatory agencies, and from industry sources. The spatial distribution of sources, power levels, frequencies, degree of frequency re-use, etc., found in the survey, are here presented. A concept is developed for scanning the earth using a directive antenna whose beam is made to rotate at a fixed angle relative to the nadir; the illuminated area swept by the beam is of the form of cycloidal annulus over a sphere. During the beam's sojourn over a point, the receiver sweeps in frequency over ranges in the order of octave width using sweeping filter bandwidths sufficient to give stable readings

Monte Carlo calibration of the SMM gamma ray spectrometer for high energy gamma rays and neutrons

The Gamma Ray Spectrometer (GRS) on the Solar Maximum Mission spacecraft was primarily designed and calibrated for nuclear gamma ray line measurements, but also has a high energy mode which allows the detection of gamma rays at energies above 10 MeV and solar neutrons above 20 MeV. The GRS response has been extrapolated until now for high energy gamma rays from an early design study employing Monte Carlo calculations. The response to 50 to 600 MeV solar neutrons was estimated from a simple model which did not consider secondary charged particles escaping into the veto shields. In view of numerous detections by the GRS of solar flares emitting high energy gamma rays, including at least two emitting directly detectable neutrons, the calibration of the high energy mode in the flight model has been recalculated by the use of more sophisticated Monte Carlo computer codes. New results presented show that the GRS response to gamma rays above 20 MeV and to neutrons above 100 MeV is significantly lower than the earlier estimates

Dewetting of Glassy Polymer Films

Dynamics and morphology of hole growth in a film of power hardening viscoplastic solid (yield stress ~ [strain-rate]^n) is investigated. At short-times the growth is exponential and depends on the initial hole size. At long-times, for n > 1/3, the growth is exponential with a different exponent. However, for n < 1/3, the hole growth slows; the hole radius approaches an asymptotic value as time tends to infinity. The rim shape is highly asymmetric, the height of which has a power law dependence on the hole radius (exponent close to unity for 0.25 < n < 0.4). The above results explain recent intriguing experiments of Reiter, Phys. Rev. Lett, 87, 186101 (2001).Comment: 4 pages, 5 figures, RevTe

Space shuttle electromagnetic environment experiment. Phase A: Definition study

A program is discussed which develops a concept for measuring the electromagnetic environment on earth with equipment on board an orbiting space shuttle. Earlier work on spaceborne measuring experiments is reviewed, and emissions to be expected are estimated using, in part, previously gathered data. General relations among system parameters are presented, followed by a proposal on spatial and frequency scanning concepts. The methods proposed include a nadir looking measurement with small lateral scan and a circularly scanned measurement looking tangent to the earth's surface at the horizon. Antenna requirements are given, assuming frequency coverage from 400 MHz to 40 GHz. For the low frequency range, 400-1000 MHz, a processed, thinned array is proposed which will be more fully analyzed in the next phase of the program. Preliminary hardware and data processing requirements are presented

Deep sequencing of Ptilidium (Ptilidiaceae) suggests evolutionary stasis in liverwort plastid genome structure

Background and aims – Organellar genome sampling is patchy for non-vascular groups, with the earliest land plants poorly represented; currently only two liverworts, two mosses and one hornwort have sequenced, annotated plastid genomes. This is in part due to methodological difficulties that have hampered attempts to generate plastid genome data from liverworts. In this paper we present a method that overcomes some of the inherent difficulties by circumventing the need for plastid enrichment, but that also provides other valuable information from nuclear and mitochondrial regions including sequences from loci that may be phylogenetically useful, and potential population-level markers such as single nucleotide polymorphisms and microsatellites. Methods – A shotgun library developed from total genomic liverwort DNA was subjected to high-throughput pyrosequencing using the Roche 454 platform. Plastid reads were bioinformatically identified, assembled and annotated. To maximize usage of the vast number of reads generated using 454 sequencing technology, combined nuclear, mitochondrial and plastid contigs were also screened for microsatellite markers, and presumed nuclear contigs were scanned for protein domains. Key Results – This is the first plastid genome to be assembled for a leafy liverwort (i.e. Ptilidium) and also the first such genome to be sequenced using next generation technology for any bryophyte. The 119,007 base long plastid genome of Ptilidium pulcherrimum contains 88 protein-coding genes, four rRNAs and thirty tRNAs. The Inverted Repeat occurs between trn V-GAC and trn N-GUU. Functional copies of the two plastid-encoded sulphate import protein-coding genes (cysA and cysT) are absent, although pseudogenes are present in the same position that the functional genes occupy in Marchantia. Microsatellites: 197 novel potential primer pairs for P. pulcherrimum were found. Presumed nuclear Ptilidium contigs gave multiple hits to Class I transposable elements. Conclusions – The arrangement of genes is identical to the plastid of the complex thalloid liverwort Marchantia, suggesting that structural rearrangements are rare in hepatics. This dataset represents a valuable resource for novel phylogenetic and population level marker design in hepatics

The Plume Impingement Contamination II Experiment: Motivation, Design, and Implementation Plan

The International Space Station (ISS) will have a long service life during which it must be able to serve as a capable platform for a wide variety of scientific investigations. In order to provide this capability, the ISS has, at the system level, a design requirement of no more than 100 Angstroms of contaminant deposition per year from "non-quiescent" sources. Non-quiescent sources include the plumes resulting from the firing of reaction control system (ReS) engines on space vehicles visiting the ISS as well as the engines on the ISS itself. Unfortunately, good general plume contamination models do not yet exist. This is due both to the complexity of the problem, making the analytic approach difficult, and to the difficulty in obtaining empirical measurements of contaminant depositions. To address this lack of flight data, NASA Johnson Space Center is planning to fly an experiment, Plume Impingement Contamination-II, to measure the contamination deposition from the Shuttle Orbiter's primary RCS engines as a function angle from plume centerline. This represents the first direct on-orbit measurement of plume impingement contamination away from the nozzle centerline ever performed, and as such is extremely important in validating mathematical models which will be used to quantify the cumulative plume impingement contamination to the ISS over its lifetime. The paper will elaborate further upon the motivation behind making these measurements as well as present the design and implementation plan of this planned experiment

An evaluation of the impact of a multidisciplinary team, in a single centre, on treatment and survival in patients with inoperable non-small-cell lung cancer

Treatment and survival of patients with inoperable Non-small-cell lung cancer in 1997 (n=117) and 2001 (n=126), before and after the introduction of a multidisciplinary team, was examined in a single centre. There were no differences in age, sex and extent of deprivation between the two years. However, in 2001, 23% of patients received chemotherapy treatment compared with 7% in 1997 (P<0.001). Median survival in 2001 was 6.6 months compared with 3.2 months in 1997 (P<0.001)

High precision quantum control of single donor spins in silicon

The Stark shift of the hyperfine coupling constant is investigated for a P donor in Si far below the ionization regime in the presence of interfaces using Tight-binding and Band Minima Basis approaches and compared to the recent precision measurements. The TB electronic structure calculations included over 3 million atoms. In contrast to previous effective mass based results, the quadratic Stark coefficient obtained from both theories agrees closely with the experiments. This work represents the most sensitive and precise comparison between theory and experiment for single donor spin control. It is also shown that there is a significant linear Stark effect for an impurity near the interface, whereas, far from the interface, the quadratic Stark effect dominates. Such precise control of single donor spin states is required particularly in quantum computing applications of single donor electronics, which forms the driving motivation of this work.Comment: 5 pages, 2 figure

Social Cognition in Adolescents with Developmental Language Disorder (DLD): Evidence from the Social Attribution Task

Social cognition impairments may explain social, emotional and behavioural difficulties (SEBD) in individuals with Developmental Language Disorder (DLD). In a novel approach, the Social Attribution Task (SAT) was used to examine this association. SAT narratives were coded from 53 participants [n = 26 DLD; n = 27 typical language development (TLD)] matched on age (Mage = 13;6) and gender (35.9% female). Parents reported SEBD. Adolescents with DLD performed worse than their TLD peers on the majority of SAT indices and had higher peer (d = 1.09) and emotional problems (d = .75). There was no association between social cognition abilities and SEBD. These exploratory findings suggest social cognition should be further examined in this population