Chemical Ecology of the host searching behavior in an Egg Parasitoid: are Common Chemical Cues exploited to locate hosts in Taxonomically Distant Plant Species?

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.

     

High-temperature Solar Thermal Energy Storage

The mislocation of solar energy production facilities and points of demand and the temporal mismatch of solar energy availability and energy demand make transport and storage of solar energy essential. Research at the Solar Energy Research Institute has focused on high-temperature, diurnal storage because of the frequency of use and the potential for conservation of premium fossil fuels. Also, high-temperature thermal energy storage can reduce the cost of hydrogen production, electricity and heat produced by cogeneration, and methane reforming. SERI research is concentrating on containment techniques (including materials corrosion, internal insulation, and storage medium for high-temperature molten salts) and direct-contact heat exchange (including cost-effective heat exchanger design and heat transfer of various materials). After initial screening tests we selected carbonates for further study. We are now constructing test equipment that will allow heat transfer experiments with molten carbonate to 700°C     

RESEARCH IN THE UNITED STATES ON HIGH-EFFICIENCY AMORPHOUS SILICON PHOTOVOLTAIC DEVICES

The purpose of this paper is to describe the research in the United States, especially the cofunded government/industry program, on amorphous silicon photovoltaic devices that has been done over the past 10 years, discuss progress achieved, describe the remaining problem areas and the future research program to overcome the remaining problems.     

Ultrastructural Study of Skeletal Fish Muscle After Freezing at Different Rates

Goldfish skeletal muscle was examined with the electron microscope to investigate the ultrastructural changes produced by freezing. Aquarium fish were used to circumvent the variables associated with catching and killing large food fish. Muscle tissue was frozen slowly in a refrigerator or quickly in liquid nitrogen. The results confirm the conclusions in the literature that fast freezing produces many small ice crystals which cause minimum dislocation of tissue ultrastructural components, whereas slow freezing generates fewer large ice crystals which distort cells and crush myofibrils. These results reveal the ultrastructural counterpart to those alterations which are visible in the light microscope using much simpler equipment and methodology [Bello et al. (1981), J. Food Sci. 46: 733].     

Improved Histological Procedure for Microscopic Demonstration of Related Changes in Fish Muscle Tissue Structure During Holding and Freezing

A simple and practical histological preparative procedure that causes minimum damage and distortion in the arrangement and organization of muscular tissue of fish was developed, which includes: fixation in Sanfelice fluid, dehydration in Cellosolve, infiltration in Parlodion, clearing in chloroform, infiltration and embedding in paraffin, sectioning (4–8 μm), and staining in a modified Massontrichrome stain. The procedure permitted the clear observation of muscle cells at the myofibrillar level. Sensible changes in the configuration and arrangement of the muscular tissue due to the rate of freezing and the postmortem condition, including spoilage, were clearly distinguished. Holding and spoilage progressively expanded the extracellular space at the expense of shrunken muscle cells and clumped myofibrils. Freezing also increased the extracellular space with cellular and myofibrillar compression between ice crystals. These alterations are diagnostic of prior tissue treatment and are easily obtained with simple histological methods.     

Five Solar-Energy Desalination Systems

This paper gives an overview of the Solar Energy Storage Program at the Solar Energy Research Institute. The program provides research, systems analyses, and economic assessments of thermal and thermochemical energy storage and transport. Current activities include experimental research into very high temperature (above 800^°C) thermal energy storage and assessment of novel thermochemical energy storage and transport systems.

The applications for such high-temperature storage are thermochemical processes, solar thermal-electric power generation, regeneration of heat and electricity, industrial process heat, and thermally regenerative electrochemical systems.

The research results for five high-temperatuTe thermal energy storage technologies and two thermochemical systems are described.