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Simulation and experimental work that compare the performance of straight and tapered monocapillaries when used with laboratory x-ray sources are reported. Detailed simulations for various taper profiles give several important conclusions for optimizing the design of a tapered monocapillary. Several tapered monocapillaries were prepared. With a 16W x-ray source, beam intensities of 4×105 photon/sec/μm2 and 3×105photon/sec/μm2 of Cu Kα x rays were obtained from the tapered monocapillaries for output diameters of 8μm and 3.5μm, respectively. These intensities are 1.4 and 1.5 times that obtained from straight capillaries with the same output beam sizes at the experimental set-up optimized for a straight capillary. In addition to the gain in x-ray flux, the tapered monocapillaries produce output beams with significantly reduced high energy bremsstrahlung radiation and increased flux stability with respect to shifts of the x-ray source spot.
It is the practise for some farmers to supplement new season lambs with concentrates, often as a creep feed, in order to get them to market early before the price declines. This concentrate is usually based on cereals and would be high in n-6 fatty acids, diluting the beneficial effect of grass grazing which promotes the n-3 polyunsaturated fatty acid (PUFA) content in the meat (Fisher et al., 2000). The purpose of this trial was to assess the addition of linseed to the concentrate, fed in a creep-feed system, which would maintain or enhance the n-3 fatty acid composition of the meat of animals fed concentrates at grass during the finishing period (Cooper et al., 2004).
We present an in-depth study of metal-poor stars, based high resolution spectra combined with newly released astrometric data from Gaia, with special attention to observational uncertainties. The results are compared to those of other studies, including Gaia benchmark stars. Chemical evolution models are discussed, highlighting few puzzles that are still affecting our understanding of stellar nucleosynthesis and of the evolution of our Galaxy.
The ability to use serving size information on food labels is important for managing age-related chronic conditions such as diabetes, obesity and cancer. Past research suggests that older adults are at risk for failing to accurately use this portion of the food label due to numeracy skills. However, the extent to which older adults pay attention to serving size information on packages is unclear. We compared the effects of numeracy and attention on age differences in accurate use of serving size information while individuals evaluated product healthfulness.
Accuracy and attention were assessed across two tasks in which participants compared nutrition labels of two products to determine which was more healthful if they were to consume the entire package. Participants’ eye movements were monitored as a measure of attention while they compared two products presented side-by-side on a computer screen. Numeracy as well as food label habits and nutrition knowledge were assessed using questionnaires.
Sacramento area, California, USA, 2013–2014.
Stratified sample of 358 adults, aged 20–78 years.
Accuracy declined with age among those older adults who paid less attention to serving size information. Although numeracy, nutrition knowledge and self-reported food label use supported accuracy, these factors did not influence age differences in accuracy.
The data suggest that older adults are less accurate than younger adults in their use of serving size information. Age differences appear to be more related to lack of attention to serving size information than to numeracy skills.
This study aimed to determine the potential role and guidelines for implementation of skill-based peer mentoring for radiotherapy planning education.
After four weekly mentoring sessions, both Year 3 mentors (n=9) and Year 2 mentees (n=9) were invited to complete a short online questionnaire relating to the impact of the initiative. The tool contained a mixture of Likert-style questions concerning student enjoyment and perceived usefulness of the initiative as well as more qualitative open questions that gathered perceptions of the peer mentoring process, implementation methods and potential future scope.
Several key discussion themes related to benefits to each stakeholder group, challenges arising, improvements and potential future directions. There were high levels of enjoyment and perceived value of the mentoring from both sides with 100% of the 18 respondents enjoying the experience. The informal format encouraged further learning, while mentors reported acquisition of valuable skills and gains in knowledge.
Peer mentoring has a valuable and enjoyable role to play in radiotherapy planning training and helps consolidate theoretical understanding for experienced students. An informal approach allows for students to adopt the most appropriate mentoring model for their needs while providing them with a free space to engender additional discussion.
The FORWARD SolarSoft IDL package is a community resource for model-data comparison, with a particular emphasis on analyzing coronal magnetic fields. FORWARD allows the synthesis of coronal polarimetric signals at visible, infrared, and radio frequencies, and will soon be augmented for ultraviolet polarimetry. In this paper we focus on observations of the infrared (IR) forbidden lines of Fe XIII, and describe how FORWARD may be used to directly access these data from the Mauna Loa Solar Observatory Coronal Multi-channel Polarimeter (MLSO/CoMP), to put them in the context of other space- and ground-based observations, and to compare them to synthetic observables generated from magnetohydrodynamic (MHD) models.
Magnetic fields in the solar atmosphere provide the energy for most varieties of solar activity, including high-energy electromagnetic radiation, solar energetic particles, flares, and coronal mass ejections, as well as powering the solar wind. Despite the fundamental role of magnetic fields in solar and heliospheric physics, there exist only very limited measurements of the field above the base of the corona. What is needed are direct measurements of not only the strength and orientation of the magnetic field but also the signatures of wave motions in order to better understand coronal structure, solar activity, and the role of MHD waves in heating and accelerating the solar wind. Fortunately, the remote sensing instrumentation used to make magnetic field measurements is also well suited to measure the Doppler signature of waves in the solar structures. We present here a mission concept for the Waves And Magnetism In the Solar Atmosphere (WAMIS) experiment which is proposed for a NASA long-duration balloon flight.
Excavations between November 1990 and February 1992 have produced important information on the date and development of the Sarn-y-bryn-caled cursus complex between 3000–2000 BC. In particular a timber circle of 2000 BC, two penannular ring-ditches and a section across the cursus monument were excavated. A radiocarbon sequence has been obtained. The results of the excavations are described in Part I. Part II comprises a discussion of the forms, dates, functions, and reconstruction of timber circles. A corpus of and chronology for timber circles is presented.
Foods and dietary patterns that enhance satiety may provide benefit to consumers. The aim of the present review was to describe, consider and evaluate research on potential benefits of enhanced satiety. The proposal that enhanced satiety could only benefit consumers by a direct effect on food intake should be rejected. Instead, it is proposed that there is a variety of routes through which enhanced satiety could (indirectly) benefit dietary control or weight-management goals. The review highlights specific potential benefits of satiety, including: providing appetite control strategies for consumers generally and for those who are highly responsive to food cues; offering pleasure and satisfaction associated with low-energy/healthier versions of foods without feeling ‘deprived’; reducing dysphoric mood associated with hunger especially during energy restriction; and improved compliance with healthy eating or weight-management efforts. There is convincing evidence of short-term satiety benefits, but only probable evidence for longer-term benefits to hunger management, possible evidence of benefits to mood and cognition, inadequate evidence that satiety enhancement can promote weight loss, and no evidence on which consumers would benefit most from satiety enhancement. The appetite-reducing effects of specific foods or diets will be much more subtle than those of pharmaceutical compounds in managing hunger; nevertheless, the experience of pharmacology in producing weight loss via effects on appetite suggests that there is potential benefit of satiety enhancement from foods incorporated into the diet to the consumer.
The Dominion Radio Astrophysical Observatory (DRAO) is carrying out a survey as part of an international collaboration to image the northe, at a common resolution, in emission from all major constituents of the interstellar medium; the neutral atomic gas, the molecular gas, the ionised gas, dust and relativistic plasma. For many of these constituents the angular resolution of the images (1 arcmin) will be more than a factor of 10 better than any previous studies. The aim is to produce a publicly-available database of high resolution, high-dynamic range images of the Galaxy for multi-phase studies of the physical states and processes in the interstellar medium. We will sketch the main scientific motivations as well as describe some preliminary results from the Canadian Galactic Plane Survey/Releve Canadien du Plan Galactique (CGPS/RCPG).
A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40°, spanning longitudes 167° through 360°to 79° at b = 0°, plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg2. The brightness temperature sensitivity will be very good, typically σT≃ 1 K at resolution 30 arcsec and 1 km s−1. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.
We have studied the etching effect of AlxGa1-xAs (0≤ x ≤ 0.5) by trisdimethylaminoarsenic (TDMAAs) at different substrate temperatures, and the quality of the resulting etched/regrown GaAs interface. We find that the etching rate of AlxGa1-x As decreases with increasing Al composition, and the interface trap density of the TDMAAs etched/regrown interface can be reduced by about a factor of 10 as deduced from capacitance-voltage carrier profiles. A smooth surface morphology of GaAs with an interface state density of 1.4×l011 cm−2 can be obtained at a lower in-situ etching temperature of 550°C. Moreover, by using this in-situ etching the I-V characteristics of regrown p-n junctions of Al0.35Ga0.65As/Al0.25Ga0.75As and Al0.35Ga0.65As/GaAs can be improved.
We present characteristics of Al/Si3N4/Si/n-GaAs metal-insulator-semiconductor (MIS) interfaces grown on GaAs(111)B prepared with a combination of in situ molecular beam epitaxy (MBE) and chemical vapor deposition (CVD) techniques . The density of the surface states in the high 1010 eV-1 cm-2 near the GaAs midgap for the GaAs grown at 575°C and 625°C was obtained. The MIS structure with GaAs homoepitaxial layer grown at 625°C, showing smoother surface morphology than the surface grown at 575 °C, exhibited small hysteresis which was as small as 30 mV under a field excursion of 1.5 MV/cm. The presence of a 1 MHz frequency response at 77 K suggests that the traps be within 60 meV of the conduction band edge of GaAs.
GaAs micro crystals in line were grown on a sulfur-terminated GaAs surface by low energy focused ion beam. Ga ions, picked out from a liquid Ga ion source, were accelerated up to 10 KV to obtain a focused ion beam. The ions were given a positive bias to reduce their kinetic energy by retarding lens.The Ga ions landed on the surface softly and formed a series of Ga droplets. By subsequent As molecule supply to the Ga droplet, GaAs micro crystals in line were grown. This method was found to be useful to make fine structures directly on the semiconductor materials.
Various optical techniques have been developed over the last few years to allow real-time analysis of regions of importance for semiconductor epitaxy, in particular the unreacted and reacted parts of the surface reaction layer (SRL) and the near-surface region of the sample. When coupled with emerging microscopic methods of calculating optical properties, these approaches will allow several levels of control beyond that which has been currently demonstrated.
We describe physics and control of Si/SiGe heterointerfaces. A clear distinction will be made between the vertical and lateral effects of the Si/SiGe interface from the viewpoint of interface engineering. Ge surface segregation during nonequilibrium MBE growth and surfactant-mediated-growth are highlighted as prominent examples for the vertical effects while interface microroughness is addressed for the lateral effects. The influence of the interface effects on radiative recombination of indirect excitons is described in the context of SiGe-based optoelectronic applications.