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Studies were conducted from 1989 to 1993 in continuous no-tillage and moldboard plow corn fields to describe rates of velvetleaf seed predation with time and with seed density, and to identify principal seed predators. Rates of seed loss from the soil surface averaged 1 to 57% day−1 and were equivalent in the two tillage systems. Predator populations were the same in no-tillage and moldboard plow fields. The predation rate was generally low in winter months, increased in mid-summer, and declined in late summer. In 2 of the 4 yr, predation increased in October and November. The predation rate was described by an exponential decay function of seed density, with high rates of seed loss at low densities and leveling off to a nearly constant level at densities above 600 seeds m−2. Predation was highest where seed access was not restricted, and exclosures of 6.5 and 1.6 cm2 reduced predation up to 15 and 52%, respectively. Mice were important predators in the field. In laboratory feeding studies, the carabid beetle Amara cupreolata, the slugs Arion subfuscus and Deroceras reticulatum, and cutworms (Agrotis ipsilon) consumed imbibed velvetleaf seeds. Amara cupreolata and A. subfuscus were the only predators to damage unimbibed velvetleaf seeds.
The integration of dissimilar materials is highly desirable for many different types of device applications but often challenging to achieve in practice. The unrivalled imaging capabilities of the aberration-corrected electron microscope enable enhanced insights to be gained into the atomic arrangements across heterostructured interfaces. This paper provides an overview of our recent observations of oxide-semiconductor heterostructures using aberration-corrected high-angle annular-dark-field and large-angle bright-field imaging modes. The perovskite oxides studied include strontium titanate, barium titanate, and strontium hafnate, which were grown on Si(001) and/or Ge(001) substrates using the techniques of molecular-beam epitaxy or atomic-layer deposition. The oxide layers displayed excellent crystallinity and sharp, abrupt interfaces were observed with no sign of any amorphous interfacial layers. The Ge(001) substrate surfaces invariably showed both 1× and 2× periodicity consistent with preservation of the 2 × 1 surface reconstruction following oxide growth. Overall, the results augur well for the future development of functional oxide-based devices integrated on semiconductor substrates.
The present study aimed to investigate socio-economic disparities in food and nutrient intakes among young Irish women. A total of 221 disadvantaged and seventy-four non-disadvantaged women aged 18–35 years were recruited. Diet was assessed using a diet history protocol. Of the total population, 153 disadvantaged and sixty-three non-disadvantaged women were classified as plausible dietary reporters. Food group intakes, nutrient intakes and dietary vitamin and mineral concentrations per MJ of energy consumed were compared between the disadvantaged and non-disadvantaged populations, as was compliance with dietary fibre, macronutrient and micronutrient intake guidelines. The disadvantaged women had lower intakes than the non-disadvantaged women of fruit, vegetables, fish, breakfast cereals, low-fat milk and wholemeal bread (all P< 0·001), yogurt (P= 0·001), low-fat spread (P= 0·002) and fresh meat (P= 0·003). They also had higher intakes of butter, processed red meats, white bread, sugar-sweetened beverages, fried potatoes and potato-based snacks (all P< 0·001) and full-fat milk (P= 0·014). Nutritionally, the disadvantaged women had higher fat, saturated fat and refined sugar intakes; lower dietary fibre, vitamin and mineral intakes; and lower dietary vitamin and mineral densities per MJ than their more advantaged peers. Non-achievement of carbohydrate (P= 0·017), fat (P< 0·001), saturated fat (P< 0·001), refined sugar (P< 0·001), folate (P= 0·050), vitamin C (P< 0·001), vitamin D (P= 0·047) and Ca (P= 0·019) recommendations was more prevalent among the disadvantaged women. Both groups showed poor compliance with Fe and Na guidelines. We conclude that the nutritional deficits present among these socially disadvantaged women are significant, but may be potentially ameliorated by targeted food-based interventions.
During in situ transmission electron microscopy (TEM) field emission
experiments, carbon nanotubes are observed to strongly diffract the
imaging TEM electron beam. We demonstrate that this effect is identical
to that of a standard electrostatic biprism. We also demonstrate that
the nanotube biprism can be used to capture electron-holographic
A transmission electron microscope (TEM) is much more than just a tool for imaging the static state of materials. To demonstrate this, we present work on studying the mechanical and electrical properties of carbon nanotube devices. Multiwall carbon nanotubes are concentrically stacked tubular sheets of graphite, where the spacing between each cylinder is simply the natural spacing of graphite. Using a custom-built in-situ nanomanipulation probe, we have shown that it is possible to slide the nanotube layers in a telescopic extension mode that exhibits low friction, demonstrating the potential of nanotubes as the ultimate synthetic nanobearing. During this telescopic extension, the electrical resistance of the nanotube devices increases, opening the possibility that these devices can also be used as nanoscale rheostats. We also briefly describe work on using electron holography inside a TEM to study the electric field distribution in nanotube field-emission devices and on using a nanotube itself as a biprism for electron holography. These measurements together demonstrate the wealth of information that can be obtained and frontiers that can be opened by putting operational nanodevices inside an electron microscope.
UHV-CVD growth based on a deuterium stabilized Sn hydride and digermane produces Ge-Sn alloys with tunable bandgaps. The Ge1−xSnx (x=2–20 at.%) alloys are deposited on Si (100) and exhibit superior crystallinity and thermal stability compared with MBE grown films. Composition, crystal and electronic structure, and optical and vibrational properties are characterized by RBS, low energy SIMS, high resolution electron microscopy TEM, x-ray diffraction, as well as Raman and IR spectroscopies. TEM studies reveal epitaxial films with lattice constants between those of Ge and Sn. X-ray diffraction shows well-defined (004) peaks and rocking curves indicate a tightly aligned spread of the crystal mosaics. Resonance Raman indicate a E1 bandgap reduction relative to Ge, consistent with a decrease of the E2 critical point observed in spectroscopic ellipsometry. IR transmission spectra indicate an increase in absorption with increasing Sn content consistent with a decrease of the direct bandgap.
General.—Ebridians, in many ways, are “neglected step-children” in the family of siliceous microplankton. Reduced to only three living species and never particularly abundant througout their history, ebridians do show up in marine, diatom-bearing sediments from practically every region of the globe.
The perception of and attitude to drinking patterns in recovering problem drinkers (N = 29) is analysed, utilizing a similar methodology to that of Richard & Burley (1978). Fault is found, however, in the latter study both in a failure to define variables and in the authors' statistical handling of the results. In the present study, it was found that controlled drinking is only seen as close to the problem drinker's concept of himself when it entails reasonably high levels of consumption. The importance of this finding for therapy is outlined. The possible negative effects of role conflict are mentioned. It is also found that problem drinkers perceive themselves as having quite different characteristics from those they themselves attribute to alcoholics. This finding is interpreted in terms of the fundamental attribution error (Jones & Nisbett, 1972).
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