The development and evaluation of an alternative powder prepregging technique for use with LaRC-TPI/graphite composites

An alternative powder prepregging method for use with LaRC-TPI (a thermoplastic polyimide)/graphite composites is investigated. The alternative method incorporates the idea of moistening the fiber prior to powder coating. Details of the processing parameters are given and discussed. The material was subsequently laminated into small coupons which were evaluated for processing defects using electron microscopy. After the initial evaluation of the material, no major processing defects were encountered but there appeared to be an interfacial adhesion problem. As a result, prepregging efforts were extended to include an additional fiber system, XAS, and a semicrystalline form of the matrix. The semicrystalline form of the matrix was the result of a complex heat treating cycle. Using scanning electron microscopy (SEM), the fiber/matrix adhesion was evaluated in these systems relative to the amorphous/XAS coupons. Based on these results, amorphous and semicrystalline/AS-4 and XAS materials were prepregged and laminated for transverse tensile testing. The results of these tests are presented, and in an effort to obtain more information on the effect of the matrix, remaining semicrystalline transverse tensile coupons were transformed back to the amorphous state and tested. The mechanical properties of the transformed coupons returned to the values observed for the original amorphous coupons, and the interfacial adhesion, as observed by SEM, was better than in any previous sample

Management of Four Alfalfa Varieties to Control Damage from Potato Leafhoppers

The main purpose of this study was to obtain information on forage yield and quality of four alfalfa (Medicago sativa L.) varieties that differed in level of resistance to potato leafhopper (Empoasca fabae Harris) yellowing, when cut at three stages of growth in the second and third cuttings in field plots, with and without insecticide application. The stages of growth were bud, 1/10, and full bloom. Other purposes included study of the same varieties in field cages manually infested at 20, 40, and 60 adult leafhoppers/square yard, and in supplemental cuttings of field plots under high natural infestation levels

Research encounters, reflexivity and supervision

Reflexivity in qualitative and ethnographic social science research can provide a rich source of data, especially regarding the affective, performative and relational aspects of interviews with research subjects. This paper explores by means of three case examples different ways of accessing and using such reflexivity. The examples are drawn from an empirical psycho-social study into the identity transitions of first-time mothers in an inner-city multicultural environment. Fieldnotes and supervision were used to engage with researcher subjectivity, to enhance the productive use of reflexivity and to address the emotional work of research. The methodology of the supervision was psychoanalytic, in its use of a boundaried frame and of psychoanalytic forms of noticing oneself, of staying engaged emotionally as well as creating a reflective distance. The examples illustrate how this can enhance the knowledge gained about the research subjects

Characterization and Analysis of Anthocyanin-Related Genes in Wild-Type Blueberry and the Pink-Fruited Mutant Cultivar ‘Pink Lemonade’: New Insights into Anthocyanin Biosynthesis

Blueberries are one of the richest sources of antioxidants, such as anthocyanins, among fruits and vegetables. Anthocyanin mutants, like the pink-fruited cultivar ‘Pink Lemonade’, are valuable resources for investigating anthocyanin biosynthesis in blueberries. In this study, we examined expression of flavonoid pathway genes during fruit development in wild-type, blue-fruited blueberries using quantitative real-time PCR. Expression was also compared between wild-type and the pink-fruited ‘Pink Lemonade’. This revealed significantly lower expression in ‘Pink Lemonade’ than in wild-type of nearly all the structural genes examined suggesting that a transcriptional regulator of the pathway was affected. Hence, we compared expression of three known regulatory genes and found that the gene encoding the transcription factor MYB1 was expressed at a significantly lower level in ‘Pink Lemonade’ than in the wild-type. To validate the capacity of this MYB1 to regulate the transcription of anthocyanin genes in blueberries, a transient expression assay was conducted. Results indicated MYB1 overexpression enhanced anthocyanin production. Comparative sequence analysis between wild-type and mutant MYB1 variants found differences in highly conserved features suggesting a mechanistic explanation for the mutant phenotype. Collectively, the results presented here contribute to a better understanding of mechanisms regulating anthocyanin biosynthesis in Vaccinium

Energy Spectrum Evolution of a Diffuse Field in Elastic Body Caused by Weak Nonlinearity

We study the evolution of diffuse elastodynamic spectral energy density under the influence of weak nonlinearity. It is shown that the rate of change of this quantity is given by a convolution of the linear energy at two frequencies. Quantitative estimates are given for sample aluminum and fused silica blocks of experimental interest.Comment: 9 pages, 3 figures; revised for better presentatio

Climate Change and Malaria in Canada: A Systems Approach

This article examines the potential for changes in imported and autochthonous malaria incidence in Canada as a consequence of climate change. Drawing on a systems framework, we qualitatively characterize and assess the potential direct and indirect impact of climate change on malaria in Canada within the context of other concurrent ecological and social trends. Competent malaria vectors currently exist in southern Canada, including within this range several major urban centres, and conditions here have historically supported endemic malaria transmission. Climate change will increase the occurrence of temperature conditions suitable for malaria transmission in Canada, which, combined with trends in international travel, immigration, drug resistance, and inexperience in both clinical and laboratory diagnosis, may increase malaria incidence in Canada and permit sporadic autochthonous cases. This conclusion challenges the general assumption of negligible malaria risk in Canada with climate change

DART Mass spectrometry as a potential tool for the differentiation of captive-bred and wild lion bones.

In recent years lion bones have been legally traded internationally to Asian markets from captive bred sources in South Africa. There are also indications of increasing instances of illegal international trade in wild lion bones. The existence of parallel captive and wild supplies of lion bone are a cause of law enforcement concern regarding the potential for the laundering of illegally sourced bones through legal trade, and present a problem for the assessment of the conservation impact of wild lion bone trade due to the difficulty of determining what market-share wild and captive-bred lion bones account for. Captive-bred and wild lion bone are visually indistinguishable and no reliable method currently exists for distinguishing them. We present a preliminary study that explores the use of DART mass spectrometry as a method to differentiate between captive-bred and wild lion bones. We find that DART is able to differentiate between a batch of captive-bred South African lion bone and a batch of wild lion bone and suggest that DART mass spectrometry shows strong potential as a tool for the regulation and investigation of lion bone trade. Further testing is needed to prove the suitability of this technique. Therefore, we suggest that further research focuses on testing the capability of DART to differentiate between contemporary wild and captive-bred lion bone originating from South Africa, and attempts to identify chemical markers in bone that can be used as indicators of captive-bred origin

Wavelet treatment of the intra-chain correlation functions of homopolymers in dilute solutions

Discrete wavelets are applied to parametrization of the intra-chain two-point correlation functions of homopolymers in dilute solutions obtained from Monte Carlo simulation. Several orthogonal and biorthogonal basis sets have been investigated for use in the truncated wavelet approximation. Quality of the approximation has been assessed by calculation of the scaling exponents obtained from des Cloizeaux ansatz for the correlation functions of homopolymers with different connectivities in a good solvent. The resulting exponents are in a better agreement with those from the recent renormalisation group calculations as compared to the data without the wavelet denoising. We also discuss how the wavelet treatment improves the quality of data for correlation functions from simulations of homopolymers at varied solvent conditions and of heteropolymers.Comment: RevTeX, 19 pages, 7 PS figures. Accepted for publication in PR