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51.
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Melanin granules melanophages and a fully‐melanized epidermis are common traits of odontocete and mysticete cetaceans 下载免费PDF全文
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Johannes Breidenbach Sonia M. Ortiz Manfred Reich 《European Journal of Forest Research》2010,129(5):813-823
Several TerraSAR-X satellite images acquired in high resolution spotlight mode with different polarisations for two study
sites in southern Germany were used to distinguish forest from other land cover classes (agriculture, built-up, water bodies)
using logistic regression models. In general, we observed that the mean and particularly the standard deviation of the backscatter
were viable measures to discriminate land cover classes. Both measures were lowest for water bodies and highest for built-up
areas, with agricultural areas and forest in intermediate positions. Trees outside forest were not differentiable from forest
with the applied method. The HH-polarised image was better suited for a classification of built-up areas, whereas the VV-polarised
image was more appropriate when classifying agricultural areas. Consequently, the combination of the two differently polarised
images leads to a significantly better model. Since forests in one study area were generally found on steeper slopes in comparison
to other land cover classes, the inclusion of terrain slope further improved the classification, which resulted in an overall
accuracy of 92–95%. Systematic differences in the parameter values of the explanatory variables for one class between the
study areas may be caused by differing class probabilities. Thus, transferring the model of one study area to the image of
another resulted in a 7–9% loss of accuracy. 相似文献
54.
J. L. Tadeo J. M. Ortiz A. Estelles 《The Journal of Horticultural Science and Biotechnology》2013,88(4):531-537
SummaryJuice and rind sugar content, fruit volume and rind colour were determined in cvs Fina, Oroval and Hernandina Clementines and in cvs Navelina, Washington Navel and Navelate oranges, cultivars that are harvested at different periods during the season. An accumulation of sugars was observed in all cultivars during ripening, mainly due to an increase of sucrose in the juice and of reducing sugars in the rind. Cv Hernandina, a late Clementine, showed a slower rate of sugar increase in rind. 相似文献
55.
Apple (Malus × domestica Borkh.) fruit intended for long-term storage are frequently harvested commercially before becoming fully ripe, often resulting in poor aroma development. Since postharvest calcium dips have proved effective for the enhancement of flavor-related volatile esters after cold storage of apples, this study was undertaken in order to assess whether preharvest calcium sprays (7 weekly applications at 1.6%, w/v, 81-123 days after full bloom) could also aid in improving this important attribute at harvest. This procedure significantly increased calcium content in treated fruit. The emission of aroma-related volatile esters by untreated and calcium-treated 'Fuji' apples was then monitored during maturation and ripening over two months prior to commercial harvest. Results indicate that most of the compounds contributing to overall flavor in ripe fruit were enhanced in response to preharvest calcium applications, suggesting that this procedure may be suitable for the improvement of fruit aroma at harvest. The emission of acetate esters was particularly favored, consistent with higher acetaldehyde contents in treated fruit. These effects arose apparently from increased pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH) activities, possibly leading to a better supply of alcohols and acyl CoAs for ester biosynthesis. 相似文献
56.
Vicente Martinez J. Maria Nuñez Antonio Ortiz Antonio Cerda 《Journal of plant nutrition》2013,36(8):1359-1368
Under conditions of salt stress, plants show qualitative and quantitative alterations in various organic compounds, such as nitrogen (N) compounds and organic acids. In this work, the effect of different saline levels as well as various N levels, supplied as nitrate (NO3) or as ammonium (NH4)+NO3 on the concentration of amino acids and organic acids in the leaves of tomato and cucumber plants has been studied. The effect of the source of N on individual amino acid contents varied with plant species. Most of the amino acids increased when the concentration of N in the nutrient solution was increased, except when N was added as NH4+NO3 for tomato. The effect of salt stress depended on which amino acid was considered. The data also indicate that the effect of salinity on each particular amino acid was greatly dependent on the plant species and N source. Organic acids were differently affected by salinity and by the N source, depending on the plant species. In tomato, the concentrations of short‐chain organic acids were 2–3 times higher in NO3‐supplied plants than in those grown with NH4+NO3. Finally, in cucumber, malic acid concentration increased as a function of the saline level in the medium. 相似文献
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Peter R. Gildemacher Wachira Kaguongo Oscar Ortiz Agajie Tesfaye Gebremedhin Woldegiorgis William W. Wagoire Rogers Kakuhenzire Peter M. Kinyae Moses Nyongesa Paul C. Struik Cees Leeuwis 《Potato Research》2009,52(2):173-205
Increased productivity of potatoes can improve the livelihood of smallholder potato farmers in Kenya, Uganda and Ethiopia
and is required to meet the growing demand. This paper investigates the opportunities for potato system improvement that could
result in improved productivity. Through a diagnosis of the potato systems in the three countries on the basis of surveys
and stakeholder workshops, seed potato quality management, bacterial wilt control, late blight control and soil fertility
management were identified as key technical intervention topics. For effective problem solving in these areas, the functioning
of the potato innovation system requires improvement to better deliver the functions of potato marketing as well as knowledge
development and information exchange. With use of a ‘system failure framework’ the shortcomings of the potato innovation system
are identified and discussed and options for improvement are suggested. 相似文献