834 research outputs found

    A Comparison and Contrast of the Idealized Role of the Secondary School Principal as Perceived by Superintendents, Principals, and Teachers

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    The differences and similarities concerning the role of the secondary school principal as perceived by superintendents, principals, and teachers was studied. All superintendents and principals and twenty-five randomly selected teachers at the five traditional high schools in the Tri-Cities provided the input from which the data was drawn and conclusions were reached. A survey questionnaire containing forty statements frequently suggested for the secondary school principal was the tool utilized for this procedure. The results showed that there were similarities of role perceptions for the secondary school principal and there were also dissimilarities of role perceptions as seen by those same groups. Recommendations for future studies of this kind were discussed at the conclusion of the thesis

    Objective Assessment and Design Improvement of a Staring, Sparse Transducer Array by the Spatial Crosstalk Matrix for 3D Photoacoustic Tomography.

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    Accurate reconstruction of 3D photoacoustic (PA) images requires detection of photoacoustic signals from many angles. Several groups have adopted staring ultrasound arrays, but assessment of array performance has been limited. We previously reported on a method to calibrate a 3D PA tomography (PAT) staring array system and analyze system performance using singular value decomposition (SVD). The developed SVD metric, however, was impractical for large system matrices, which are typical of 3D PAT problems. The present study consisted of two main objectives. The first objective aimed to introduce the crosstalk matrix concept to the field of PAT for system design. Figures-of-merit utilized in this study were root mean square error, peak signal-to-noise ratio, mean absolute error, and a three dimensional structural similarity index, which were derived between the normalized spatial crosstalk matrix and the identity matrix. The applicability of this approach for 3D PAT was validated by observing the response of the figures-of-merit in relation to well-understood PAT sampling characteristics (i.e. spatial and temporal sampling rate). The second objective aimed to utilize the figures-of-merit to characterize and improve the performance of a near-spherical staring array design. Transducer arrangement, array radius, and array angular coverage were the design parameters examined. We observed that the performance of a 129-element staring transducer array for 3D PAT could be improved by selection of optimal values of the design parameters. The results suggested that this formulation could be used to objectively characterize 3D PAT system performance and would enable the development of efficient strategies for system design optimization

    Climate Signals in Wine Quality Time-Series of North-East Hungary

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    Today’s viticulture regions for quality wine production are located in relatively narrow geographical and therefore climatic niches that put them at greater risk from climate change than other more broad acre crops. Our target area, the Mátra Region is close to the edge of optimal wine production concerning its climate conditions. Fifty year (1961-2010) wine and quality (natural sugar content, in weight % of must) data are analysed and compared to parallel climate variables. Two sets of station-based monthly temperature, sunshine duration and precipitation data, taken from neighbouring stations, Eger-Kőlyuktető (1961-2010) and Kompolt (1976-2006) are used altogether in 132 combinations. In addition, daily grid-point data provided by the CarpatClim Project are used (www.carpatclim-eu.org/pages/home). By now it is clear that (1) wine quality, is in significant negative correlation with the annual precipitation and in positive correlation with temperature and sunshine duration. (2) Applying a wide combination of monthly data we obtain even stronger correlations (higher significance according to t-tests) even from the station-based data, but it is difficult to select and optimum model from the many proper combinations just slightly differing in performance over the test sample. (3) The interpolated areal averages of the grid-point data promise good results, but their statistical analysis by using 5-day averages is just in its initial phase. It is clearly seen that June 5-day temperature means strongly influence the sugar content in the Mátra-region of NE Hungary

    RNAi suppression of xylan synthase genes in wheat starchy endosperm

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    The xylan backbone of arabinoxylan (AX), the major cell wall polysaccharide in the wheat starchy endosperm, is synthesised by xylan synthase which is a complex of three subunits encoded by the GT43_1, GT43_2 and GT47_2 genes. RNAi knock-down of either GT43_1 or all three genes (triple lines) resulted in decreased AX measured by digestion with endoxylanase (to 33 and 34.9% of the controls) and by monosaccharide analysis (to 45.9% and 47.4% of the controls) with greater effects on the amount of water-extractable AX (to 20.6 and 19.9% of the controls). Both sets of RNAi lines also had greater decreases in the amounts of substituted oligosaccharides released by digestion of AX with endoxylanase than in fragments derived only from the xylan backbone. Although the GT43_1 and triple lines had similar effects on AX they did differ in their contents of soluble sugars (increased in triple only) and on grain size (decreased in triple only). Both sets of transgenic lines had decreased grain hardness, indicating effects on cell wall mechanics. These results, and previously published studies of RNAi suppression of GT43_2 and GT47_2 and of a triple mutant of GT43_2, are consistent with the model of xylan synthase comprising three subunits one of which (GT47_2) is responsible for catalysis with the other two subunits being required for correct functioning but indicate that separate xylan synthase complexes may be responsible for the synthesis of populations of AX which differ in their structure and solubility

    Loss of TaIRX9b gene function in wheat decreases chain length and amount of arabinoxylan in grain but increases cross-linking

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    Wheat contains abundant xylan in cell walls of all tissues, but in endosperm there is an unusual form of xylan substituted only by arabinose (arabinoxylan; AX) that has long chains and low levels of feruloylation, a fraction of which is extractable in water (WE-AX). WE-AX acts as soluble dietary fibre but also gives rise to viscous extracts from grain, a detrimental trait for some non-food uses of wheat. Here we show that a glycosyl transferase family 43 wheat gene abundantly expressed in endosperm complements the Arabidopsis irx9 mutant and so name the three homoeologous genes TaIRX9b. We generated wheat lines with a constitutive knock-out of TaIRX9b by stacking loss-of-function alleles for these homeologues from a mutagenized hexaploid wheat population resulting in decreases in grain extract viscosity of 50-80%. The amount and chain length of WE-AX molecules from grain of these triple stack lines was decreased accounting for the changes in extract viscosity. Imaging of immature wheat grain sections of triple stacks showed abolition of immunolabelling in endosperm with LM11 antibody that recognises epitopes in AX, but also showed apparently normal cell size and shape in all cell types, including endosperm. We identified differentially expressed genes from endosperm of triple stacks suggesting that compensatory changes occur to maintain this endosperm cell wall integrity. Consistent with this, we observed increased ferulate dimerisation and increased cross-linking of WE-AX molecules in triple stacks. These novel wheat lines lacking functional TaIRX9b therefore provide insight into control of wheat endosperm cell walls

    Diaminothiazoles Modify Tau Phosphorylation and Improve the Tauopathy in Mouse Models

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    Although Tau accumulation is a feature of several neurodegenerative conditions, treatment options for these conditions are nonexistent. Targeting Tau kinases represents a potential therapeutic approach. Small molecules in the diaminothiazole class are potent Tau kinase inhibitors that target CDK5 and GSK3?. Lead compounds from the series have IC50 values toward CDK5/p25 and GSK3? in the low nanomolar range and no observed toxicity in the therapeutic dose range. Neuronal protective effects and decreased PHF-1 immunoreactivity were observed in two animal models, 3Ă—Tg-AD and CK-p25. Treatment nearly eliminated Sarkosyl-insoluble Tau with the most prominent effect on the phosphorylation at Ser-404. Treatment also induced the recovery of memory in a fear conditioning assay. Given the contribution of both CDK5/p25 and GSK3? to Tau phosphorylation, effective treatment of tauopathies may require dual kinase targeting

    A path toward understanding neurodegeneration

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    The specter of neurodegenerative disease, particularly Alzheimer's disease, haunts the developed world and exacts a poorly documented toll on underdeveloped countries. With so little progress made toward finding a cure—or, better, a prevention—it is time to rethink the path to progress. This requires a change in perspective on the type of research that will make a difference. The lesson learned from cancer research is that a new commitment means rethinking the fundamental approach to the disease. Cancer research moved from taking potshots with, usually, cytotoxic drugs to a bottom-up, mechanism-based approach in which newly acquired genetic knowledge played the largest role. Today, that effort has produced a platform of knowledge from which academia and industry are drawing. For neurodegenerative disease, the genetic approach remains valid but the problem must concurrently be approached from a complementary, robust cell biological perspective, focusing on the cellular cascade of events that lead to neuronal cell death
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