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The recent ban on animal protein sources as livestock feed has lead to an increased demand for alternative protein sources (Salgado et al., 2001). Soya protein has been suggested as a potential alternative to fishmeal in weaner diets in sustainable pig production systems. However, the digestion of soya products is known to be reduced by the presence of antinutritional factors such as protease inhibitors and lectins (Lallès, 1993). Several methods have been devised to refine soya thereby increasing ileal digestibility’s (Shon et al, 1994). Some of the refined products include isolate soy protein and soybean protein concentrate. The objective of this experiment was to compare the effect of replacing fishmeal (FO) with HP 300 a soya isolate product on growth performance of piglets from weaning to 28 days post weaning under commercial conditions.
Single and multi-mode room temperature laser action was observed in GaN pyramids under strong optical pumping. The 5- and 15-micron-wide hexagonal-based pyramids were laterally overgrown on a patterned GaN/AlN seeding layer grown on a (111) silicon substrate by metal-organic chemical vapor deposition. The pyramids were individually pumped, imaged, and spectrally analyzed through a high magnification optical system using a high density pulsed excitation source. We suggest that the cavity formed in a pyramid is of a ring type, formed by total internal reflections of light off the pyramids’ surfaces. The mode spacing of the laser emission was found to be correlated to the size of pyramids. The effects of pyramid geometry and pulse excitation on the nature of laser oscillations inside of the pyramids is discussed. Practical applications of the results for the development of light-emitting pixels and laser arrays are suggested.
Two crystal forms, orthorhombic and cubic, of satellite tobacco mosaic virus have been investigated. Atomic force microscopy showed that the orthorhombic crystals were characterized by a high density of point defects, while the cubic crystals were practically defect-free. Nonetheless, orthorhombic crystals diffract to a high resolution of 1.8 Å while the cubic crystals diffract to only about 4 to 6 Å resolution. Differences in the properties of viruses incorporated into the two crystal structures were demonstrated by growth kinetics studies. It appears that physical and chemical treatments applied to protein and virus solutions during their extraction and purification introduce a variety of specific structural changes and that these alterations may then affect the diffraction properties of resultant macromolecular crystals.
The application of genetic and molecular biological methods to the engineering of proteins, the engine of the biotechnology revolution, has become increasingly dependent on knowledge of protein, nucleic acid and virus molecular structure. Structural information of high precision, essential to this enterprise, can only be obtained through X-ray crystallographic techniques. The quality of this information is directly a function of the properties and degree of perfection of the crucial intermediates, the macromolecular crystals. As a consequence, there is now broad and intense interest in developing new methods, procedures and reagents for the nucleation and growth of such crystals. There is, in addition, an expanded interest in the properties of biological crystals and the use of physical measurements in improving approaches to growing better and larger crystals. Here some of the fundamentals of macromolecular crystal growth will be reviewed, and some current trends in the field remarked upon, including the new initiative to develop a national structural genomics program.
Based on experimental findings obtained earlier by the authors , a model is devised in which the divergence of the vacancy flow created in the grain boundaries of Al-Si(1%) metallizations by high-density DC is attributed to temperature gradients and structural features. Void nuclei of critical size are created in areas of high vacancy concentration. These nuclei grow, fed by the electromigrational vacancy current. It is shown that stresses have only a negligible' effect on the vacancy diffusion but influence the nucleation process dramatically. Results expressed in terms of fraction of void area are calculated and then correlated with experimental results. Certain material parameters, whose values are not known, are derived from the experimental data. The physical significance of these parameters is discussed.
Single and multi-mode room temperature laser action was observed in GaN pyramids under strong optical pumping. The 5- and 15-micron-wide hexagonal-based pyramids were laterally overgrown on a patterned GaN/AlN seeding layer grown on a (111) silicon substrate by metal-organic chemical vapor deposition. The pyramids were individually pumped, imaged, and spectrally analyzed through a high magnification optical system using a high density pulsed excitation source. We suggest that the cavity formed in a pyramid is of a ring type, formed by total internal reflections of light off the pyramids' surfaces. The mode spacing of the laser emission was found to be correlated to the size of pyramids. The effects of pyramid geometry and pulse excitation on the nature of laser oscillations inside of the pyramids is discussed.
We present a comprehensive study of the optical characteristics of AlxGa1−xN epilayers by means of photoluminescence (PL), PL excitation, and time-resolved PL spectroscopy. All AlxGa1−xN epilayers were grown by metalorganic chemical vapor deposition and the Al mole fraction (x) was varied from 0 to 0.6. We observed that (i) the full width at half maximum of the PL emission, (ii) the energy difference between the PL emission peak energy and the PLE absorption edge, and (iii) the effective lifetime increase with increasing x. These facts indicate that degree of band-gap fluctuation due to a spatially inhomogeneous Al alloy content distribution increases with increasing x. We observed anomalous temperature-induced emission shift behavior for AlxGa1−xN epilayers, specifically, an S-shaped (decrease-increase-decrease) temperature dependence of the peak energy with increasing temperature. This anomalous temperature-dependent emission behavior was enhanced as the Al mole fraction was increased. Since the band-gap fluctuation in AlxGa1−xN epilayers due to inhomogeneous spatial variations of the Al content increases with increasing Al content, we believe that band-gap fluctuation causes the PL peak energy to deviate from the typical temperature dependence of the energy gap shrinkage. Therefore, the anomalous temperature-induced emission shift can be attributed to energy tail states due to alloy potential inhomogeneities in the AlxGa1−xN epilayers with large Al content.
The single radial haemolysis test is conveniently practical and economical and promises to have wide applicability in the study of influenza antibodies in human populations. It can also be adapted for preliminary examination of new virus isolates during epidemics.
Using this test a rather higher proportion of the population in the Highland Region of Scotland was found to possess antibody to a recent epidemic strain of influenza (A/Scotland/74) than was the case in the south of England. Antibody was detected and apparently evenly spread throughout all but the most remote island communities. Some evidence of the spread of the subsequent variant, A/Victoria/75, was obtained. Most of the school children in our study had high antibody titres to recent strains but the proportion with high antibody titres to these strains declined speedily from the age of 17 years onwards.
Event-related potentials were recorded using color
pictures of real objects. Participants made relatedness
judgments for pictures that were highly, moderately, or
unrelated to a picture of a preceding prime object (Experiment
1) or object identification decisions for related/easily
identified, unrelated/easily identified, and unrelated/unidentifiable
objects preceded by prime objects (Experiment 2). Unrelated
pictures elicited larger event-related potential negativities
between 225 and 500 ms than did related pictures, although
the first portion of this epoch had a more frontal distribution
than did the later portion. The later epoch differentiated
the unrelated from the moderately related and the moderately
related from the highly related pictures (Experiment 1),
but the early epoch produced differences only between the
unrelated and related pictures (Experiments 1 and 2). This
pattern supports the existence of two separate components,
an anterior, image-specific N300 and a later, central/parietal
To compare the mortality rates of vegetarians and non-vegetarians.
Collaborative analysis using original data from five prospective studies. Death rate ratios for vegetarians compared to non-vegetarians were calculated for ischaemic heart disease, cerebrovascular disease, cancers of the stomach, large bowel, lung, breast and prostate, and for all causes of death. All results were adjusted for age, sex and smoking. A random effects model was used to calculate pooled estimates of effect for all studies combined.
USA, UK and Germany.
76, 172 men and women aged 16–89 years at recruitment. Vegetarians were those who did not eat any meat or fish (n = 27,808). Non-vegetarians were from a similar background to the vegetarians within each study.
After a mean of 10.6 years of follow-up there were 8330 deaths before the age of 90 years, including 2264 deaths from ischaemic heart disease. In comparison with non-vegetarians, vegetarians had a 24% reduction in mortality from ischaemic heart disease (death rate ratio 0.76, 95% CI 0.62–0.94). The reduction in mortality among vegetarians varied significantly with age at death: rate ratios for vegetarians compared to non-vegetarians were 0.55 (95% CI 0.35—0.85), 0.69 (95% CI 0.53–0.90) and 0.92 (95% CI 0.73–1.16) for deaths from ischaemic heart disease at ages <65, 65–79 and 80–89 years, respectively. When the non-vegetarians were divided into regular meat eaters (who ate meat at least once a week) and semi-vegetarians (who ate fish only or ate meat less than once a week), the ischaemic heart disease death rate ratios compared to regular meat eaters were 0.78 (95% CI 0.68–0.89) in semi-vegetarians and 0.66 (95% CI 0.53–0.83) in vegetarians (test for trend P<0.001). There were no significant differences between vegetarians and non-vegetarians in mortality from the other causes of death examined.
Vegetarians have a lower risk of dying from ischaemic heart disease than non-vegetarians.
Life histories of Conophthorus beetles attacking the shoot tips of jack, red, Scotch, and ponderosa pines were studied and compared with the life history of the red pine cone beetle, Conophthorus resinosae Hopkins. The tip-infesting beetles have not been morphologically separated from C. resinosae. The beetles attacking the shoots of jack, red, Scotch, and ponderosa pines have similar life histories which differ from that of C. resinosae. The latter is distinctly univoltine, while the tip-infesting beetles appear to be bivoltine. Also, dates of appearance and seasonal development differ.
Behavioral differences between a Conophthorus beetle attacking jack pine shoot tips and the red pine cone beetle, C. resinosae Hopkins, were studied. In field experiments the red pine cone beetle attacked cones and shoots of both pines but preferred cones over shoots and red pine cones over jack pine cones. The jack pine tip beetle attacked both jack pine and red pine snoots, but no progeny appeared in red pine shoots. In laboratory tests, the red pine cone beetle survived equally well in vapors of simulated red and jack pine shoot resin, while the jack pine tip beetle survived best in the jack pine resin vapor. The jack pine tip beetle is described as a new species, Conophthorus banksianae McPherson.
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