A variably saturated soil moisture flow model is developed for planted soils with depth varying properties by incorporating a nonuniform macroscopic root water uptake function. The model includes spatial and temporal variation of the root density with dynamic root growth for simulating water uptake by plants along with the impact of soil moisture availability. The governing partial differential moisture flow equation integrated over the depth with a plant water uptake term is solved numerically by the implicit finite difference method using an iterative scheme. The model is first tested for barren soils for two profiles considering constant and depth varying soil characteristics under constant inflow condition. The results obtained are later tested with experimental data available in the literature. A nonuniform plant water uptake term is subsequently incorporated in the model and water uptake by wheat plants under different soil moisture availability conditions is studied. Finally, the moisture flow model is validated with field data of rain fed wheat (Triticum aestivum) using a dynamic root growth model for a layered root zone soil profile. The simulated soil moisture regime of the layered root zone shows a reasonably good agreement with the observed data. 相似文献
The formation of conjugated diene hydroperoxides and hexanal was compared to the development of aroma profiles during initial
lipid oxidation of a vegetable oil and its 40% oil-in-water emulsion at 60°C. The aroma profiles of the oil and the emulsion
with and without addition of ascorbic acid or ascorbyl palmitate were compared. The aroma compounds were isolated under a
model mouth system and analyzed by gas chromatography/sniffing port analysis. Detectable odors were found and corresponded
to 11 and 14 volatile compounds in the oil and the emulsion, respectively. The emulsion had higher lipid oxidation rates than
the oil. Addition of ascorbic acid and ascorbyl palmitate had little influence on the aroma composition of the oil. In the
emulsion, addition of these compounds resulted in diminished generation of odor active compounds. Results of measurements
of conjugated diene hydroperoxides and headspace hexanal corresponded to that of the lipid oxidation rate in general, but
predicted insufficiently the alterations in the aroma compositions by antioxidants. 相似文献
It is well established that plants infested with a single herbivore species can attract specific natural enemies through the
emission of herbivore-induced volatiles. However, it is less clear what happens when plants are simultaneously attacked by
more than one species. We analyzed volatile emissions of lima bean and cucumber plants upon multi-species herbivory by spider
mites (Tetranychus urticae) and caterpillars (Spodoptera exigua) in comparison to single-species herbivory. Upon herbivory by single or multiple species, lima bean and cucumber plants emitted
volatile blends that comprised mostly the same compounds. To detect additive, synergistic, or antagonistic effects, we compared
the multi-species herbivory volatile blend with the sum of the volatile blends induced by each of the herbivore species feeding
alone. In lima bean, the majority of compounds were more strongly induced by multi-species herbivory than expected based on
the sum of volatile emissions by each of the herbivores separately, potentially caused by synergistic effects. In contrast,
in cucumber, two compounds were suppressed by multi-species herbivory, suggesting the potential for antagonistic effects.
We also studied the behavioral responses of the predatory mite Phytoseiulus persimilis, a specialized natural enemy of spider mites. Olfactometer experiments showed that P. persimilis preferred volatiles induced by multi-species herbivory to volatiles induced by S. exigua alone or by prey mites alone. We conclude that both lima bean and cucumber plants effectively attract predatory mites upon
multi-species herbivory, but the underlying mechanisms appear different between these species. 相似文献
Site‐specific immobilization of peptides and proteins is crucial to ensure their functionality in surface‐based assays. We report the use of aniline‐catalyzed oxime ligations as a very efficient and broadly applicable method to covalently attach the N terminus of proteins and peptides to a surface functionalized with alkoxy‐amine groups.
Plants may defend themselves against herbivores by enhancing the effectiveness of natural enemies of herbivores. This is termed indirect defense, which may be induced by herbivore damage. An important aspect of induced indirect defense is the attraction of the herbivore's natural enemies to infested plants by the plant emitting so-called herbivore-induced synomone (HIS) in response to herbivore damage. In this paper, we review the role of terpenoids in the induced indirect defense of plants against herbivorous mites. HIS are emitted from both damaged and undamaged areas of infested plants, and the composition of HIS varies among different plant species. The emission of HIS may also vary within a plant species, depending upon: (1) plant cultivar, (2) leaf growth stage, (3) the herbivore species that is attacking, and (4) abiotic conditions (light intensity, time of year, and water stress). Predatory mites cope with this variation of HIS by innate recognition as well as temporary specialization to a certain HIS via learning. 相似文献
We introduce the generalized nonogram, an extension of the well‐known nonogram or Japanese picture puzzle. It is not based on a regular square grid but on a subdivision (arrangement) with differently shaped cells, bounded by straight lines or curves. To generate a good, clear puzzle from a filled line drawing, the arrangement that is formed for the puzzle must meet a number of criteria. Some of these relate to the puzzle and some to the geometry. We give an overview of these criteria and show that a puzzle can be generated by an optimization method like simulated annealing. Experimentally, we analyze the convergence of the method and the remaining penalty score on several input pictures along with various other design options. 相似文献
Oxygenated ex situ machine perfusion of donor livers is an alternative for static cold preservation that can be performed at temperatures from 0 °C to 37 °C. Organ metabolism depends on oxygen to produce adenosine triphosphate and temperatures below 37 °C reduce the metabolic rate and oxygen requirements. The transport and delivery of oxygen in machine perfusion are key determinants in preserving organ viability and cellular function. Oxygen delivery is more challenging than carbon dioxide removal, and oxygenation of the perfusion fluid is temperature dependent. The maximal oxygen content of water-based solutions is inversely related to the temperature, while cellular oxygen demand correlates positively with temperature. Machine perfusion above 20 °C will therefore require an oxygen carrier to enable sufficient oxygen delivery to the liver. Human red blood cells are the most physiological oxygen carriers. Alternative artificial oxygen transporters are hemoglobin-based oxygen carriers, perfluorocarbons, and an extracellular oxygen carrier derived from a marine invertebrate. We describe the principles of oxygen transport, delivery, and consumption in machine perfusion for donor livers using different oxygen carrier-based perfusion solutions and we discuss the properties, advantages, and disadvantages of these carriers and their use. 相似文献
Metallurgical and Materials Transactions B - In order to better understand the metallic droplet behavior during a slag treatment process, a physical modeling based on the similarity principle was... 相似文献