Search Results - (Author, Cooperation:D. J. Campbell)

2018-12-21

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

2012-07-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Host-Pathogen Interactions ; Humans ; Immunity ; Intestines/immunology/microbiology/pathology ; Metagenome/*immunology ; Mice ; Skin/*immunology/*microbiology ; Skin Diseases, Bacterial/*immunology/pathology ; T-Lymphocytes/*immunology

2018-09-04

Rockefeller University Press

0022-1007

1540-9538

Medicine

Infectious Disease and Host Defense

1089-7674

AIP Digital Archive

Physics

The International Thermonuclear Experimental Reactor FEAT design for a long-pulse tokamak burning plasma experiment (R=6.2 m, a=2 m, B=5.3 T, I=15 MA) is intended to achieve extended burn in inductively driven deuterium–tritium plasmas with the ratio of fusion power to auxiliary heating power, Q, of at least 10 and a nominal fusion power output of ∼500 MW. It also aims to demonstrate steady-state plasma operation using noninductive current drive with a Q of at least 5. Particular features of the design are: a significant operating window for Q=10 inductive operation; long inductive pulses (several hundred seconds burn); a capability for studying steady-state scenarios, specifically in cases where α-particles make a significant contribution to the plasma pressure; disruption physics processes which are comparable to those expected at the reactor scale; and an α-particle density and heating power which permit the key issues of α-particle confinement and α-particle driven magnetohydrodynamic instabilities to be investigated under conditions appropriate to a reactor. © 2001 American Institute of Physics.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Oabjective The aim of this study was to ascertain the normal range of amniotic fluid alphafetoprotein (AFP) levels from 8 to 18 weeks of pregnancy.Design Amniotic fluid samples obtained by amniocentesis were analysed by radioimmunoassay for AFP. From 8 to 12 weeks, fluid was obtained by transvaginal amniocentesis prior to termination of pregnancy. Samples from 13 to 18 weeks were obtained from amniotic fluid specimens submitted for cytogenetic analysis.Setting A tertiary referral prenatal diagnostic service.Subjects Two hundred thirty-seven women between 8 and 18 weeks gestation.Results High levels of AFP were present in amniotic fluid at 8 weeks (median 83.0 kU/ml), falling rapidly to 11 weeks (median 19.9 kU/ml) (P〈0.01). Levels then rose to a peak at 13 weeks (median 30.7 kU/ml), thereafter falling to 18 weeks.Conclusions A single coherent view of the levels of AFP from 8 to 18 weeks of pregnancy is presented for the first time. The rapid changes and complex pattern of AFP levels in early pregnancy suggest that interpretation of amniotic fluid AFP levels in the diagnosis of neural tube defects may be more difficult between 8 and 13 weeks of pregnancy than in the second trimester.

Electronic Resource

1365-2389

Blackwell Publishing Journal Backfiles 1879-2005

Geosciences

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Soil compaction is a concern worldwide, particularly where compactible soils are used for intensive agriculture in a wet climate. We have investigated the impact of compaction and the associated changes in soil structural qualities on crop production and environmental pollution. The overall objective was to develop soil management systems that provide suitable conditions for crop growth and minimize environmental damage. We ran large-scale field experiments studying the preservation of structural quality in arable and permanent grassland, using management systems such as the control or elimination of field traffic and the application of conservation tillage and zero tillage. We measured bulk density, shear strength, cone resistance, macroporosity, relative diffusivity, air permeability and water infiltrability to identify soil qualities that could be used for selecting suitable soil management. Along with crop yield, we measured environmental impacts, such as the emissions of nitrous oxide from the soil, which require the interaction of soil structure and water content near the soil surface. Soil structure influenced wetness, which affected trafficability, compaction and nitrogen retention. Measurement of properties that affect fluid storage and transport, such as macroporosity, provided soil quality indices that helped in recommending suitable soil management systems. Spatial variation of structure associated with wheel-track locations could be estimated rapidly using a cone penetrometer. Variation was particularly important in determining crop yield consistency. Crop productivity and soil structural qualities were preserved best when field traffic was eliminated. A reduced ground-pressure system successfully minimized compaction in grassland but was less effective in an arable rotation. Unless traffic is eliminated, good timing of operations is the most effective way to preserve soil structural quality.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

The first two channels of the JET electron cyclotron emission diagnostic have been in regular use for several months. A Michelson interferometer provides several hundred broadband spectral measurements (with time resolution 15 ms) on every plasma pulse. The second cyclotron harmonic in these spectra is used to deduce absolutely calibrated electron temperature profiles in the outer half of the plasma. Current measurements and their interpretation will be discussed, and the full diagnostic system, for the determination of two-dimensional profiles, will be described.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1365-2044

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have evaluated the performance of the Intersurgical 40% Oxygen Recovery T-Kit in ten healthy volunteers, Inspired oxygen and end-tidal carbon dioxide. concentrations were measured during normal respiration and with variations in respiratory rate and depth. The performance of the device was then studied after modifications to the inspiratory limb, the expiratory, limb and the arrangement of the attachments to the T -piece. The standard arrangement of the T piece was associated with inadequate inspired oxygen concentration (31.9±0.6%), independent of respiratory rate and depth. All three modifications increased the inspired oxygen concentration, the longer expiratory limb to 34.6% (p 〈 0.01)and the altered T piece arrangement to 37.3% (p 〈 0.01). The highest inspired oxygen concentration of 40.3% (p 〈 0.01)was obtained by increasing the length of the inspiratory limb.

Electronic Resource

1747-6593

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

The paper reviews various options adopted in the UK for engineered protection measures aimed at preventing pollution to the environs of landfill sites. The advantages and limitations of both natural and synthetic lining materials are discussed, recognizing the constraints posed by the geometry and geology of prospective landfill sites. Particular attention is given to the Environmental Safety Centre experience with techniques designed to minimize both leachate and gaseous emissions, and hence prevent pollution of ground and surface waters, and reduce hazards to nearby property. Options for operational practices and restoration procedures are discussed in relation to the control of degradation processes and polluting potential. Included in these options are design and operation of leachate and gas collection/treatment systems, phasing of landfilling operations, and progressive restoration of sites. Monitoring requirements are emphasized as a vital measure of the success or failure of site designs and operational practices in ensuring that appropriate environmental protection is achieved and maintained.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

The resonance hyper-Raman (RHR) scattering of CH3I vapor is observed as blue incident radiation is tuned through two-photon resonance with the ν2 vibronic absorption band of the predissociative B˜←X˜ Rydberg transition in the UV. In analogy to linear resonance Raman spectroscopy, the RHR band shapes and polarization are found to be a sensitive function of the two-photon resonant vibronic state lifetime and detuning. The dependence of these scattering characteristics on the two-photon excited-state dephasing constant provides a technique for determining subpicosecond predissociation rates via nonlinear spontaneous Raman scattering. Theoretical fits to the observed resonant rovibrational hyper-Raman depolarization ratio dispersion curves are obtained for a vibronic B-state lifetime of 0.5±0.2 ps. This lifetime value is in agreement with previous results obtained from linear resonance Raman scattering studies. The polarization analysis of RHR scattering, in particular, provides a technique for measuring excited-state lifetimes of molecular transitions in the VUV.

Electronic Resource

0156-7446

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Economics

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] We have recently examined the brains of ten hedgehogs (Erinaceus europaeus) in coronal, horizontal and sagittal sections, and found cells apparently identical with mast cells which are localized to the diencephalon. These cells were observed only in the thalamus, epithalamus and metathalamus, and ...

Electronic Resource

1572-946X

Springer Online Journal Archives 1860-2000

Physics

Abstract This paper describes the detailed calibration at soft X-ray energies (0.1–2.0 keV; 125 Å-6 Å) of gold coated, paraboloidal X-ray mirrors, four of which were subsequently flow on the Ariel-6 satellite. Uncertainties in the attitude of the satellite together with an apparent reduction in sensitivity of the soft X-ray experiment necessitated observations using the Crab Nebula as a reference. These showed that a dramatic reduction in the reflection efficiencies of all four mirrors had occurred, almost certainly after or during launch. An initial recalibration of the mirrors using the Crab observation is described.

Electronic Resource

1432-1939

Buffer zone ; Edge-effect corrections ; Density estimates ; Granite tors ; Buzzard territories

Springer Online Journal Archives 1860-2000

Biology

Abstract When analysing spatial pattern, aggregation and regularity are normally regarded as being mutually exclusive and a two-tailed test is applied to check whether or not there is a deviation from random expectation towards one or the other. However any fine-scale regularity occurring in crowded patches is likely to be masked by the larger-scale aggregation using this approach. An associated problem is that edge effects are particularly severe for small patchy populations. An inclusive analysis utilising one-tailed nearest-neighbour tests to check for aggregation and regularity separately is described. In addition the technique resolves the edge-effect problem. The approach is illustrated using a synthetic patchy population, and is then applied to a population of granite tors showing both large-scale aggregation and fine-scale regularity. Regular spacing of buzzard territories is discussed briefly.

Electronic Resource

1432-1939

Territoriality ; Spatial competition ; Boundary independence ; Acorn woodpeckers

Springer Online Journal Archives 1860-2000

Biology

Abstract Organisms can aggregate to form patches or clusters interspersed with interstices of unoccupied space for behavioural or ecological reasons. Territorial spacing in the clusters could follow, resulting in regularity. In these circumstances an analysis of spatial pattern in a sample area defined by a boundary enclosing the clusters might reveal the aggregation but not the regularity. To demonstrate the occurrence of regularity, spacing trends and an estimate of density based on a nearest-neighbour graphical analysis can be used. The method is independent of boundaries and the presence of interstices. The basis of the method, and its strengths and limitations, are examined. A re-analysis of acorn woodpecker data, which has generated some controversy in the past, illustrates its potential for revealing “hidden” regularity.

Electronic Resource

1432-1939

Nearest neighbours ; Graphical analysis ; Spatal competition

Springer Online Journal Archives 1860-2000

Biology

Summary The most crowded individuals in a population often compete for space and develop a regular pattern of spacing. Such regularity is not normally recognized because it occurs within high-density regions of a populated area showing overall aggregation. Thus competition for space, as reflected by spatial pattern, often goes undetected when standard tests for spatial randomness are used. The test described in this paper makes use of truncated samples of nearest-neighbour distances arranged in ascending order, so that only the pattern of spacing of the most crowded individuals is analysed. This is the basis of Pielou's test (1962, 1977) for spatial competition. An advantage of the approach described is that the density of the most crowded individuals is determined graphically. The graphical method also provides a means for choosing an appropriate, non-arbitrary, truncation point for the test. The test was applied to two samples of singing crickets to demonstrate the procedure. The biological significance of the spacing patterns identified is discussed.

Electronic Resource

1432-0878

Springer Online Journal Archives 1860-2000

Biology

Medicine

Summary Further studies of the neurohypophysis of the hedgehog have confirmed the presence of two distinct types of neurosecretory fibre in the infundibular process. A third type of fibre, possibly containing catecholamines, is found in the upper infundibular stem. Lesions of the paraventricular nuclei result in vacuolation of type I nerve fibres, which contain crystal-like and aggregate bodies. Type II fibres, containing membranous inclusions, with or without osmiophilic material, apparently do not degenerate. The evidence suggests that type I fibres arise in both the paraventricular and supraoptic nuclei.

Electronic Resource