Studies on the Potato Sprout Suppressant/Fungicide Tecnazene

This thesis describes work relating to the use of potato sprout suppressant chemicals - compounds which are used to control the sprouting of potatoes during extended storage. In particular, several implications of the use, in commercial situations, of one of these compounds, tecnazene, were assessed. This included a study on the effects on subsequent field growth of a range of tecnazene residues in seed potatoes at planting - this chemical having previously been cited as a cause of delayed emergence and reduced yield. A storage experiment and field trial are described from which it was concluded that a specific effect on emergence and yield cannot be attributed to a given residue at planting, although this can be a useful guide in broader terms. It was considered that a residue at planting of less than 1-1.5 mg/kg on a whole tuber basis would have little effect on emergence and yield. It was also noted that tecnazene treatment resulted in an increased number of stems from each tuber, and in turn to a higher proportion of smaller tubers. This effect was noted for even the lowest application rate indicating that tecnazene treatment could perhaps be used to manipulate tuber size distribution while having little or no effect on emergence and total yield. The method of residue analysis employed in the above work is described in a separate section, along with an assessment of tecnazene toxicology. Two other commercial problems linked to the use of sprout suppressants were investigated, both of which are related to the use of tecnazene in large scale commercial potato stores: The effect of vapour phase application of tecnazene on the healing of tuber wounds is discussed, based on results obtained using a rapid method for assessment of the degree of suberisation and periderm development. Tecnazene treatment appeared to have no detrimental effect on wound healing in contrast to the other major sprout suppressant chemical, chlorpropham, which clearly inhibited the process. This is an important point as incomplete healing of tuber wounds results in water loss and facilitates infection by fungal or bacterial pathogens. The effect of tecnazene, either alone or in combination with chlorpropham, on the incidence of internal sprouting in treated tubers was also studied. This phenomenon occurs when sprouts grow into a tuber rather than out and away from tuber, and renders such tubers useless for processing into crisps. The results indicated that while internal sprouting can occur in the absence of tecnazene, the pattern of sprouting induced by tecnazene treatment would appear to increase the incidence of this disorder. The remaining section of work in this thesis was based on a subject of less practical significance, but of much interest - the mode of action of tecnazene. It was considered that tecnazene might act by inhibiting gibberellin biosynthesis or action and for this reason bean seedling bioassays were conducted in which very dilute aqueous solutions of tecnazene were fed to the plants. This did result in some growth inhibition when compared to controls although it was not nearly as marked as that effected by a known gibberellin biosynthesis inhibitor which was included in these assays, a fact which could possibly be partly explained by the very limited aqueous solubility of tecnazene. Any growth inhibition induced by tecnazene could be overcome by application of exogenous GA3, although, again partly for reaons of solubility, this need not necessarily implicate gibberellin biosynthesis inhibition or site blocking. Further work, probably at the cell constituent level, is required

Perceptions of Oklahoma Educational Administrators and School Board Members Relative to Federal Involvement in Local Education

Educational Administratio

Modeling Expert Opinions on Food Healthiness: A Nutrition Metric

Background Research over the last several decades indicates the failure of existing nutritional labels to substantially improve the healthiness of consumers' food and beverage choices. The difficulty for policy-makers is to encapsulate a wide body of scientific knowledge in a labeling scheme that is comprehensible to the average shopper. Here, we describe our method of developing a nutrition metric to fill this void. Methods We asked leading nutrition experts to rate the healthiness of 205 sample foods and beverages, and after verifying the similarity of their responses, we generated a model that calculates the expected average healthiness rating that experts would give to any other product based on its nutrient content. Results The form of the model is a linear regression that places weights on 12 nutritional components (total fat, saturated fat, cholesterol, sodium, total carbohydrate, dietary fiber, sugars, protein, vitamin A, vitamin C, calcium, and iron) to predict the average healthiness rating that experts would give to any food or beverage. We provide sample predictions for other items in our database. Conclusions Major benefits of the model include its basis in expert judgment, its straightforward application, the flexibility of transforming its output ratings to any linear scale, and its ease of interpretation. This metric serves the purpose of distilling expert knowledge into a form usable by consumers so that they are empowered to make healthier decisions.

Norms from the Georgia Centenarian Study: Measures of verbal abstract reasoning, fluency, memory, and motor function

We previously presented normative data from a relatively large, population-based sample (n = 244) of centenarians and a reference group of octogenarians (n = 80) for several brief, global neurocognitive tasks adapted for use for older adults with physical and sensory limitations (Miller et al., 2010 Miller, L. S., Mitchell, M. B., Woodard, J. L., Davey, A., Martin, P., Poon, L. W., … Siegler, I. C. (2010). Cognitive performance in centenarians and the oldest old: Norms from the Georgia Centenarian Study. Neuropsychological, Development, and Cognition. Section B: Aging, Neuropsychology and Cognition, 17, 575–590. doi: 10.1080/13825585.2010.481355[Taylor & Francis Online], [Web of Science ®], [Google Scholar], Neuropsychological, Development, and Cognition. Section B: Aging, Neuropsychology and Cognition, 17, 575). Here, we present additional normative data on several domain-specific tasks from these samples from Phase III of the Georgia Centenarian Study, including measures of verbal abstract reasoning, fluency, memory, and motor function. Expected age differences were demonstrated across all cognitive measures, and, consistent with our previous findings, centenarians showed a stronger association between age and performance. Normative tables are presented unweighted as well as population-weighted, and stratified by age and education level. These findings offer a unique contribution to the literature on cognitive aging, as normative performance in this age group is understudied and largely unavailable to clinicians and researchers

Cognitive Performance in Centenarians and the Oldest Old: Norms from the Georgia Centenarian Study

We present normative data from a large population-based sample of centenarians for several brief, global neurocognitive tasks amenable for frail elders. Comparative data from octogenarians are included. A total of 244 centenarians and 80 octogenarians from Phase III of the Georgia Centenarian Study were administered the Mini-Mental Status Examination, Severe Impairment Battery, and Behavioral Dyscontrol Scale. Centenarians (age 98–107) were stratified into three age cohorts (98–99, 100–101, 102–107), octogenarians into two 5- year cohorts (80–84, 85–89). Highly significant differences were observed between groups on all measures, with greater variation and dispersion in performance among centenarians, as well as stronger associations between age and performance. Descriptive statistics and normative ranges (unweighted and population-weighted) are provided by age cohort. Additional statistics are provided by education level. While most previous centenarian studies have used convenience samples, ours is population-based and likely more valid for comparison in applied settings. Results suggest centenarians look different than do even the oldest age range of most normative aging datasets (e.g., 85–90). Results support using global measures of neurocognition to describe cognitive status in the oldest old, and we provide normative comparisons to do so

Scanning X-ray nanodiffraction from ferroelectric domains in strained K0.75Na0.25NbO3 epitaxial films grown on (110) TbScO3

Scanning X-ray nanodiffraction on a highly periodic ferroelectric domain pattern of a strained K0.75Na0.25NbO3 epitaxial layer has been performed by using a focused X-ray beam of about 100 14;nm probe size. A 90°-rotated domain variant which is aligned along [1 2]TSO has been found in addition to the predominant domain variant where the domains are aligned along the [12]TSO direction of the underlying (110) TbScO3 (TSO) orthorhombic substrate. Owing to the larger elastic strain energy density, the 90°-rotated domains appear with significantly reduced probability. Furthermore, the 90°-rotated variant shows a larger vertical lattice spacing than the 0°-rotated domain variant. Calculations based on linear elasticity theory substantiate that this difference is caused by the elastic anisotropy of the K0.75Na0.25NbO3 epitaxial layer