2 results
Integrating prescribed burning and clopyralid for the management of yellow starthistle (Centaurea solstitialis)
- Joseph M. DiTomaso, Guy B. Kyser, Jessica R. Miller, Sergio Garcia, Richard F. Smith, Glenn Nader, J. Michael Connor, Steve B. Orloff
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- Journal:
- Weed Science / Volume 54 / Issue 4 / August 2006
- Published online by Cambridge University Press:
- 20 January 2017, pp. 757-767
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Prescribed burning and the herbicide clopyralid are very effective tools for the management of yellow starthistle. However, repeated use of either can be impractical or can present other problems. The potential solution is the development of an effective integrated weed management strategy using a combination of the two approaches. In small plot studies (0.2 ha), we tested one of five possible treatments: (1) untreated control, (2) 2 consecutive yr of clopyralid (0.105 kg ha−1), (3) 2 consecutive yr of prescribed summer burning, (4) first-year clopyralid followed by second-year prescribed burning, and (5) first-year prescribed burning followed by second-year clopyralid. Treatments were made in 1999 and 2000 at three study sites in California (San Benito, Yuba, and Siskiyou counties). In 2001, the year following the final treatment, 2 consecutive yr of clopyralid or first-year burning followed by second-year clopyralid consistently reduced yellow starthistle cover in the following year by 92 to 100%. However, at the Yuba site, clopyralid alone increased medusahead and ripgut brome cover. Although 2 consecutive yr of burning was effective in Yuba, very high levels of starthistle infestation in San Benito were not completely burned in the second year because of the lack of available consumable fuel. Clopyralid treatment the first year followed by prescribed burning in the second year stimulated yellow starthistle germination and did not reduce the infestation. In a large-scale study conducted at two sites (13 and 81 ha) in southern Monterey County, we used a first-year burn followed by either 2 yr of clopyralid (0.158 kg ha−1) or a single year of clopyralid (0.210 kg ha−1) and a subsequent burn. Results were in close agreement with those found in the small-scale studies. In the year following the final treatment, control of yellow starthistle was greater than 99% when the burn was followed by 2 yr of clopyralid. In contrast, when a prescribed burn was used in the last year of the program, the level of control was not as good, probably because of the increased germination of the remaining soil seedbank. These results indicate that a first-year prescribed burn followed by a second-year clopyralid treatment can provide consistently good control of yellow starthistle, as well as reduced levels of noxious annual grasses, including medusahead and ripgut brome.
11 - The role of the lateral nucleus of the amygdala in auditory fear conditioning
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- By Hugh T. Blair, Department of Psycology University of California 1285 Franz Hall Box 951563 Los Angeles, CA 90095-1563, Karim Nader, Department of Psychology McGill University Canada Stewart Biological Sciences Building Room N8/8, 398-3511 1205 Dr Penfield Avenue Montreal, Quebec, H3 A 1B1, Glenn E. Schafe, Department of Psychology and Interdisciplinary Neuroscience Program Yale University 2 Hillhouse Avenue New Haven, Connecticut 06511-6814, Elizabeth P. Bauer, W. M. Keck Foundation Laboratory of Neurobiology Center for Neural Science 6 Washington Place, Room 276 New York University New York, NY 10003, Sarina M. Rodrigues, W. M. Keck Foundation Laboratory of Neurobiology Center for Neural Science New York University New York, New York 10003, Joseph E. LeDoux, University Professor; Professor of Neural Science and Psychology Center for Neural Science New York University 4 Washington Place, Room 809 New York, NY 10003
- Edited by James R. Pomerantz, Rice University, Houston
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- Book:
- Topics in Integrative Neuroscience
- Published online:
- 08 August 2009
- Print publication:
- 21 February 2008, pp 299-325
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Summary
Introduction
Classical fear conditioning is a form of associative learning in which subjects are trained to express fear responses to a neutral conditioned stimulus (CS) that is paired with an aversive unconditioned stimulus (US). As a result of such pairing, the CS comes to elicit behavioral, autonomic, and endocrine responses that are characteristically expressed in the presence of danger (Blanchard & Blanchard, 1969; Bolles & Fanselow, 1980; Smith et al., 1980). Fear conditioning has emerged as an especially useful behavioral model for investigating the neurobiological mechanisms of learning and memory, because fear memories are rapidly acquired and long-lasting, involve well-defined stimuli and responses, and depend upon similar neural circuits in different vertebrate species (see Davis & Lee, 1998; LeDoux, 2000; Maren, 1999; Rogan et al., 2001).
In this chapter, we review studies that have investigated the role of the amygdala in fear learning. We argue that neural plasticity in the lateral amygdala is critical for storing memories of the association between the CS and US during fear conditioning, and discuss how learning and memory are achieved at the cellular or molecular level. Alternative views of amygdala contributions to fear conditioning are also considered.
The amygdala and fear conditioning
Fear learning depends critically upon the amygdala (Davis & Shi, 2000; Fendt & Fanselow, 1999; LeDoux, 1996, 2000), a cluster of nuclei in the brain's temporal lobe that plays a key role in regulating emotions (Kluver & Bucy, 1939; LeDoux, 1996).