Revised; Originally Published: 2004 / 3 pp. / Wheat and barley are the two major small grain crops in Arizona. These crops can produce yields near maximum at a wide range of seeding rates due to yield component compensation. Grain yield is determined by plants per unit area, tillers per plant, kernels per head, and kernel weight. At a low seeding rate, the plant will compensate for fewer plants per unit area by producing more tillers per plant and larger heads. At a high seeding rate, fewer tillers are produced compared to a low seeding rate, and the heads are smaller. Therefore, grain yields near maximum can be produced at a wide range of seeding rates if conditions are favorable (see Fig. 1). Weed control can be a problem at low seeding rates and lodging may be a problem at high seeding rates. The optimum seeding rate for small grains depends on a variety of factors which will be discussed

No description available.

No description available.

The properties of a polymer surface can be manipulated by the addition of a small quantity of surface active functionalised polymer to the bulk. On annealing above the glass transition these low surface energy functional groups attach to the air/polymer interface forming a brush like layer. To quantify this effect perdeuterated polystyrenes with fluoroalkane groups at specific locations in the polymer have been blended with unmodified polystyrene. Three key areas have been studied; effect of molecular architecture; effect of the molecular weight of the matrix polymer; and the rate of formation of the segregating layer. The complementary techniques of neutron reflectometry and nuclear reaction analysis have been used to determine the near surface depth profile of the deuterated polymer. Architectures studied were linear polystyrene with functional groups at both ends of the polymer chain, a 3-armed star with a functional core and linear polystyrene with functional groups evenly spaced along the chain. The architecture affected the shape of the composition profile but had little effect on the surface volume fraction and surface excess values obtained for the same bulk volume fraction. Self-consistent field theory simulations were carried out to determine the 'sticking energy' of the functional groups and good comparisons were obtained between the experimental volume fraction profiles and those predicted. Some segregation of functional polymer was observed during sample preparation and equilibrium segregation was obtained in less than one hour for 50000 M(_W) linear polymer up to eight hours for the 3-armed star after annealing under vacuum at 413K. For the difunctional polystyrene the functional groups did not have a significant affect on the rate of diffusion compared to non-functional polystyrene and diffusion coefficients obtained ranged from 6x10(^-16) to 9x10(^-15) cm(^2)s(^-1) The 3-armed star had the lowest diffusion coefficient value of 2xl0(^-16) cm(^-2)s(^-1) because of the inability for branched molecules to diffuse by reptation.

The main research question of this study is: What discourses of learning and identity do students develop in relation to their individual learning histories, their experience of learning and of knowledge-acquisition in the HE environment, and how critically reflective are students of the positioning enacted through the dominant discourses of the HE environment with particular regard to institutional discourses of academic learning and knowledge? Rationale: The university is seen as a significant stage in the development of students' learning histories, of particular relevance for the students' perceptions of self, learning and knowledge. The role of discourses of knowledge acquisition and learning in talk - 'learning discourses' - is examined against the background of general study conditions for students poised between study and work. The case study: methodology and methods The dissertation, which is an example of computer-aided qualitative research, describes a small-scale ethnographic study of students at a German university. The researcher adopts a broadly ethnomethodological approach. The data was collected in a limited number of individual in-depth research interviews to construct a language corpus. Other data regarding the research site was collected via observation and from documentary sources. Data analysis: the interview transcripts were analysed using a mixture of conversation analysis; institutional discourse(s) analysis and narrative analysis. Results: the study provides evidence of the production of learning biographies in interview talk. Evidence is also produced in this study of the 'biographization' of students' talk. The coherence of students' discourse practices in relation to their experience of learning is underlined and the researcher argues that the student respondents negotiate the intrinsic difficulties of asymmetrical institutional talk by deploying a range of discourses, both institutionally-generated as well as individual discourses of resistance and opposition. The evidence of individual discourse practices provided by the data employed here is seen as a strong argument for a <b>low-inference</b> approach to data analysis. The results produced by analysis of the interview transcripts demonstrate the central importance of heteroglossic elements in talk, - here described as <b>'embedded speech'</b> and understood to function as a <b>’plausibility device'</b> - in the process of self-expression and the production of own discourse Relevance This research is seen as relevant for university learning strategies, for the appreciation of student self-perception, their discourses of knowledge and resistance to the prevailing 'human capital' discourses of learning, exam success and career orientation of HE study.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Bibliography: leaves 163-170. / Microfiche. / xvi, 189 leaves, bound ill. 29 cm

Thesis (Ph.D.)--Tufts University, 2002. / Adviser: Robert Cook. Submitted to the Dept. of Psychology. Includes bibliographical references (leaves 151-158). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2007. / Includes bibliographical references (leaves 100-101). Also available in electronic version.

This thesis reports investigations into laser ablation inductively coupled plasma emission spectrometry for rapid elemental analysis of a diverse range of samples: glasses, aqueous solutions, oils, coated steels and glasses, and biological samples. Bulk analysis of glasses for major, minor and trace elements is reported. Results showed that element emission responses are dependent upon laser operating conditions. With optimised operating conditions of a Q switched laser operating at 60 J for 5 s ablation time with the laser defocused by 5 mm above the sample surface. The limits of detection are in the sub ug g -1 level with precision ranging from 6.6 %RSD for a non volatile element such as boron to 23 %RSD for a volatile element silver. Although the principal aim of using aqueous multielement solutions as novel calibration standards for quantitative analysis of other liquids was not achieved, optimised laser operating parameters needed for microsampling of aqueous solutions and analytical performance data were obtained. The optimum laser operating conditions for a 20 ul sample were found to be the same as for glasses and were as follows: a Q switched laser operating at 60 J for a 5 s ablation time with the laser defocused by 5 mm above the sample surface. Transport efficiencies of approximately 30 % can be achieved, compared to < 1% by pneumatic nebulisation. Also there was no differential loss of elements by laser ablation which may occur with electrothermal vaporisation. Limits of detection were found to be in the sub ug ml -1 level. Precisions were typically between 6.6 and 12 %RSD. The main cause for lack of precision was spattering of the sample. Microsampling of oils by laser ablation proved to be an effective and accurate technique for rapid determination of element concentration without the need for sample filtration or digestion. Precision proved to be better than for aqueous solutions, typically from 3 to 7 %RSD, because of a reduction in spattering. The same optimum laser operating conditions used for aqueous solutions were identical for oils. This thesis reports the first experiments to fully utilise laser ablation as a routine method for quantitative measurement of coating depth for coated steels and glasses. It was found that the peak width at half the maximum height was proportional to the coating thickness (over a range of 1 to 10 um). With optimised laser operating conditions a depth resolution of less than 1 um was achieved. The optimum laser operating conditions were as follows: a Q switched laser ran continuously with a laser lamp energy of 60 J at 10 Hz pulse repetition rate. Finally experiments show the great potential for the use of laser ablation as a microsampling technique for microtome tissue samples. Micro depth analysis of nickel distribution in skin shows that the technique could differentiate between two skin samples with different nickel concentrations. The use of gel multielement standards as a novel calibration technique for analysis of microtome tissue samples has also been demonstrated. Optimum laser operating condition were to use a moderate laser energy of 750 V with the laser defocused 5 mm above the sample surface.