Parasitoids are known to exploit volatile cues emitted by plants after herbivore attack to locate their hosts. Feeding and oviposition of a polyphagous herbivore can induce the emission of odor blends that differ among distant plant species, and parasitoids have evolved an incredible ability to discriminate them and locate their hosts relying on olfactive cues. We evaluated the host searching behavior of the egg parasitoid Cosmocomoidea annulicornis (Ogloblin) (Hymenoptera: Mymaridae) in response to odors emitted by two taxonomically distant host plants, citrus and Johnson grass, after infestation by the sharpshooter Tapajosa rubromarginata (Signoret) (Hemiptera: Cicadellidae), vector of Citrus Variegated Chlorosis. Olfactory response of female parasitoids toward plants with no herbivore damage and plants with feeding damage, oviposition damage, and parasitized eggs was tested in a Y-tube olfactometer. In addition, volatiles released by the two host plant species constitutively and under herbivore attack were characterized. Females of C. annulicornis were able to detect and significantly preferred plants with host eggs, irrespectively of plant species. However, wasps were unable to discriminate between plants with healthy eggs and those with eggs previously parasitized by conspecifics. Analysis of plant volatiles induced after sharpshooter attack showed only two common volatiles between the two plant species, indole and β-caryophyllene. Our results suggest that this parasitoid wasp uses common chemical cues released by many different plants after herbivory at long range and, once on the plant, other more specific chemical cues could trigger the final decision to oviposit.
ABSTRACT This paper reviews the technology of wood drying and recent developments in the field. The importance of drying is reviewed first. Then the fundamentals of wood properties as they relate to drying are discussed, including how water is held in wood, how it moves through wood, and how drying stresses that lead to drying defects develop. Traditional drying technology for lumber, veneer, and heavy timbers is then presented. With this background, the discussion moves to recent developments in drying technology that have been implemented commercially, such as high-temperature drying, low-temperature drying, continuously rising temperature drying, vacuum drying, and advances in process control. Finally, a discussion is presented on drying technology of the future. This topic describes processes that offer potential improvements in drying technology, but are still in the research and development stage. 相似文献
Using a sensitive direct gas analysis technique, an attempt was made to detect hydrogen evolution from copper corroding in neutral oxygen free chloride solutions. No hydrogen was detected at evolution rates 3 orders of magnitude lower than those reported for copper in pure water. 相似文献
Aflatoxins are secondary metabolites produced by species of Aspergilli, specifically Aspergillus flavus and Aspergillus parasiticus. These molds are ubiquitous in nature and grow on a variety of substrates, thereby producing aflatoxins. Aflatoxins are of great concern due to their biochemical and biological effects on living organisms. In this article, the occurrence of aflatoxins, their biosynthesis, factors influencing their production, their effects on living organisms, and methods of detection and control in food are reviewed. Future areas of research involving mathematical modeling of factors influencing aflatoxin production and alternative methods of control, such as modified atmosphere packaging, are also discussed. 相似文献
Pulse crops are cool season, annually grown legume crops, which are harvested for their seeds. They are invaluable agricultural commodities which are produced and imported by many regions of the world. Pulse seeds are a valuable source of dietary protein, carbohydrates, fiber and an important source of essential vitamins and minerals. Their nutritional characteristics have been associated with a reduction in the incidence of various cancers, HDL cholesterol, type-2 diabetes and heart disease. Pulses also contain protein and non-protein antinutritional factors, which may cause deleterious effects on the host when the seeds or processed seeds are consumed raw. Conversely, recent studies have demonstrated that protein antinutritional compounds such as lectins, protease inhibitors and the non-antinutritional component, angiotensin I-converting enzyme (ACE) inhibitor may have beneficial properties. Lectins have been associated with reducing certain forms of cancer, activating innate defense mechanisms and managing obesity. Protease inhibitors such as trypsin and chymotrypsin inhibitors have been demonstrated to reduce the incidence of certain cancers and demonstrate potent anti-inflammatory properties. Angiotensin I-converting enzyme (ACE) inhibitor has been associated with a reduction in hypertension. 相似文献
Objective: Unintentional injury rates in low- and middle-income countries are up to 50 times higher than high-income nations. In South Africa, kerosene (paraffin) is a leading cause of poisoning and burns, particularly in low-income communities where it serves as a primary fuel for light, cooking, and heating. This study tested a community-based intervention to reduce kerosene-related injury risk. The intervention used a train-the-trainers model, whereby expert trainers train local paraprofessionals, who in turn deliver educational materials to community residents. The intervention was theory-driven, pragmatically motivated, and culturally sensitive. Design: Prospective quasi-experimental intervention design with nonequivalent case versus control groups. Main Outcome Measures: Three primary outcome measures were considered: self-reported knowledge of kerosene safety, observed practice of safe kerosene use, and self-reported recognition of risk for kerosene-related injury. Results: ANOVA models suggest a large and significant increase in self-reported kerosene-related knowledge in the intervention community compared to the control community. There were smaller, but statistically significant changes, in kerosene-related safety practices and recognition of kerosene injury risk in the intervention community compared to the control community. Conclusion: The intervention was successful. A train-the-trainers model might be an effective educational tool to reduce kerosene-related injury risk in low-income communities within low- and middle-income countries. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
Geographic information systems have finally arrived in state and local governments and, with them, an extraordinary opportunity for planning. Many groups with differing agendas are competing to define this new technology, what it will do, and who will use it. It is by no means certain that planners will do well in this competition. This article mines the literature on technological innovation and concludes that planners must understand GIS as a socially constructed technology, including not just hardware and software but also the practices, laws, organizational arrangements, and knowledge that are necessary for its use. The article recommends a strategic approach to GIS implementation that involves both human and technical systems. 相似文献