Phytochrome D Acts in the Shade-Avoidance Syndrome in Arabidopsis by Controlling Elongation Growth and Flowering Time1

Shade avoidance in higher plants is regulated by the action of multiple phytochrome (phy) species that detect changes in the red/far-red ratio (R/FR) of incident light and initiate a redirection of growth and an acceleration of flowering. The phyB mutant of Arabidopsis is constitutively elongated and early flowering and displays attenuated responses to both reduced R/FR and end-of-day far-red light, conditions that induce strong shade-avoidance reactions in wild-type plants. This indicates that phyB plays an important role in the control of shade avoidance. In Arabidopsis phyB and phyD are the products of a recently duplicated gene and share approximately 80% identity. We investigated the role played by phyD in shade avoidance by analyzing the responses of phyD-deficient mutants. Compared with the monogenic phyB mutant, the phyB-phyD double mutant flowers early and has a smaller leaf area, phenotypes that are characteristic of shade avoidance. Furthermore, compared with the monogenic phyB mutant, the phyB-phyD double mutant shows a more attenuated response to a reduced R/FR for these responses. Compared with the phyA-phyB double mutant, the phyA-phyB-phyD triple mutant has elongated petioles and displays an enhanced elongation of internodes in response to end-of-day far-red light. These characteristics indicate that phyD acts in the shade-avoidance syndrome by controlling flowering time and leaf area and that phyC and/or phyE also play a role.

Chloroplast-Avoidance Response Induced by High-Fluence Blue Light in Prothallial Cells of the Fern Adiantum capillus-veneris as Analyzed by Microbeam Irradiation1

Chloroplast movement was induced by partial cell illumination using a high-fluence blue microbeam in light-grown and dark-adapted prothallial cells of the fern Adiantum capillus-veneris. Chloroplasts inside the illuminated area moved out (high-fluence response [HFR]), whereas those outside moved toward the irradiated area (low-fluence response [LFR]), although they stopped moving when they reached the border. These results indicate that both HFR and LFR signals are generated by high-fluence blue light of the same area, and that an LFR signal can be transferred long-distance from the beam spot, although an HFR signal cannot. The lifetime of the HFR signal was calculated from the traces of chloroplast movement induced by a brief pulse from a high-fluence blue microbeam to be about 6 min. This is very short compared with that of the LFR (30–40 min; T. Kagawa, M. Wada [1994] J Plant Res 107: 389–398). These data indicate that the signal transduction pathways of the HFR and the LFR must be distinct.

Spontaneous avoidance behavior in Drosophila null for calmodulin expression.

The regulatory protein calmodulin is a major mediator of calcium-induced changes in cellular activity. To analyze the roles of calmodulin in an intact animal, we have generated a calmodulin null mutation in Drosophila melanogaster. Maternal calmodulin supports calmodulin null individuals throughout embryogenesis, but they die within 2 days of hatching as first instar larvae. We have detected two pronounced behavioral abnormalities specific to the loss of calmodulin in these larvae. Swinging of the head and anterior body, which occurs in the presence of food, is three times more frequent in the null animals. More strikingly, most locomotion in calmodulin null larvae is spontaneous backward movement. This is in marked contrast to the wild-type situation where backward locomotion is seen only as a stimulus-elicited avoidance response. Our finding of spontaneous avoidance behavior has striking similarities to the enhanced avoidance responses produced by some calmodulin mutations in Paramecium. Thus our results suggest evolutionary conservation of a role for calmodulin in membrane excitability and linked behavioral responses.

Memory enhancement by intrahippocampal, intraamygdala, or intraentorhinal infusion of platelet-activating factor measured in an inhibitory avoidance task.

Platelet-activating factor (PAF; 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine), which is thought to be a retrograde messenger in long-term potentiation (LTP), enhances glutamate release and LTP through an action on presynaptic nerve endings. The PAF antagonist BN 52021 blocks CA1 LTP in hippocampal slices, and, when infused into rat dorsal hippocampus pre- or posttraining, blocks retention of inhibitory avoidance. Here we report that memory is affected by pre- or posttraining infusion of the PAF analog 1-O-hexadecyl-2-N-methylcarbamoyl-sn-glycerol-3-phosphocholine (mc-PAF) into either rat dorsal hippocampus, amygdala, or entorhinal cortex. Male Wistar rats were implanted bilaterally with cannulae in these brain regions. After recovery from surgery, the animals were trained in step-down inhibitory avoidance or in a spatial habituation task and tested for retention 24 h later. mc-PAF (1.0 microgram per side) enhanced retention test performance of the two tasks when infused into the hippocampus before training without altering training session performance. In addition, mc-PAF enhanced retention test performance of the avoidance task when infused into (i) the hippocampus 0 but not 60 min after training; (ii) the amygdala immediately after training; and (iii) the entorhinal cortex 100 but not 0 or 300 min after training. In confirmation of previous findings, BN 52021 (0.5 microgram per side) was found to be amnestic for the avoidance task when infused into the hippocampus or the amygdala immediately but not 30 or more minutes after training or into the entorhinal cortex 100 but not 0 or 300 min after training. These findings support the hypothesis that memory involves PAF-regulated events, possibly LTP, generated at the time of training in hippocampus and amygdala and 100 min later in the entorhinal cortex.

Influences of psychological and experiential processes in paintings of Sheila Sobol

"For a number of artists, the activity of making. art is an inquiry into: the nature of art, the true nature of reality, and the execution of artistic ideas. This inquiry ·is benefited by recognizing psychological processes and theories, subjectl.ve and external experiences, and technical and aesthetic knowledge. The "creative process" contains this inquiry and can be likened to a hinge which connects the art produced and the artist"

Educating a New Cadre of Experts Specializing in Digital Collections and Digital Curation: Experiential Learning in Digital Library Curriculum

Integration of experiential learning into the library and information science (LIS) courses has been a theme in LIS education, but the topic deserves renewed attention with an increasing demand for professionals in the digital library field and in light of the new initiative announced by the Library of Congress (LC) and the Institution of Museum and Library Services (IMLS) for national residency program in digital curation. The balance between theory and practice in digital library curricula, the challenges of incorporating practical projects into LIS coursework, and the current practice of teaching with hands on activities represent the primary areas of this panel discussion.

The Politics of Budget Consolidation in Britain and Germany: the Impact of Blame-Avoidance Opportunities. CES Germany & Europe Working Papers, No. 05.2, 2005

According to parts of the literature, blame avoidance opportunities, i.e. the necessity and applicability of blame avoidance strategies, may differ among countries according to the respective institutional set-ups and between governing parties according to their programmatic orientation. In countries with many veto actors, a strategy of "Institutional Cooperation" among these actors is expected to diffuse blame sufficiently to render other blame avoidance strategies obsolete. In contrast, governments in Westminster democracies should resort to the more unilateral strategies of presentation, policy design and timing. At the same time, parties of the left are expected to have an easier time implementing spending cuts while right parties are less vulnerable when proposing tax increases. Evidence from the politics of budget consolidation in Britain and Germany does not corroborate these hypotheses. Instead, it seems that party competition conditions the effects institutions and the partisan complexion of governments have on the politics of blame avoidance.

Results of Minicars RSV crash avoidance tests conducted in West Germany.

National Highway Traffic Safety Administration, Washington, D.C.

Collision avoidance radar braking systems investigation - phase III study. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Collision avoidance radar braking systems investigation - phase III study, technical report. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Preliminary human factors guidelines for crash avoidance warning devices.

Federal Highway Administration, Office of Crash Avoidance Research, Washington, D.C.

Accident avoidance evaluation of General Motors experimental safety vehicle. Final report.

National Highway Traffic Safety Administration, Washington, D.C.

Analytical modeling of driver response in crash avoidance maneuvering. Volume I: technical background. Final report.

National Highway Traffic Safety Administration, Washington, D.C.