An analysis of the previous method for testing tolerances of noxious weed seeds was performed. Problems of the current techniques were discussed, and the solution to these problems was given. A new technique of testing through the sequential test ratio was developed, and results examined. The sequential test was found to be useful enough to include the use of it in determining tolerances for noxious weed seeds. This study did show that the use of sequential tests does have excellent potential and flexibility as a statistical tool for the tolerances of noxious weed seeds. (75 pages)

Yellow starthistle (Centaurea solstitialis L.) is an introduced Asteraceae that has become established on 10 million acres in the Pacific Northwest and California. This weed functions as an annual or short-lived perennial and depends on seeds for reproduction. Strategies of control that reduce plant fitness or lower seed production or viability may help limit the rate of spread of yellow starthistle. Previous work has shown that grazing and mowing can influence seed production. This study tested the hypothesis that proper timing and frequency of defoliation can reduce the number and viability of seeds produced. The study was conducted in Umatilla County, Oregon using a randomized block design with 4 replications of each of 4 defoliation treatments: (1) single defoliation at the bolting stage; (2) single defoliation at the bud stage; (3) two defoliations, once at the bolting stage and again at the bud stage; (4) non-defoliated control. Each of 4 blocks consisted of a 12 x 12 m area, with 16 plots measuring 3 x 3 m. Plants were defoliated at ground level using a gas-powered string-type mower. Response measurements were collected at the end of the growing season (September) following potential regrowth and included: (1) number of seedheads per plant; (2) number of seeds per seedhead; (3) number of seeds per plant; (4) number of seeds m⁻², (5) seed viability (% germination rates). Supporting measurements included: seedhead diameter; plant height, number of branches per plant; pre-dawn xylem pressure; soil moisture; and documentation of 5 biological control insect species. A single defoliation at bolting resulted in fewer seeds per seedhead, and fewer seeds per plant than non-defoliated controls. A single defoliation at the floral bud stage or repeated defoliation (bolting and again at the bud stage) resulted in equally fewer seeds per plant and fewer seeds m⁻² compared to non-defoliated controls. There was no statistical difference in percent germination of seeds among treatments. Defoliation had no effect on the infestation rates of seedheads by biological control insects. A second study examined nutrient content of yellow starthistle during 6 phenological stages from sites in Union, Baker and Umatilla Counties, Oregon during each of 2 years. Acid detergent fiber, lignin, cellulose and neutral detergent fiber contents increased through phenological development. Crude protein ranged from 16.7 to 5.0%. In Vitro dry matter digestibility ranged from 84.8% to 57.0%. Mineral nutrients P, K, CA, Mg, Mn, Fe, Cu, Zn, and Na were analyzed and determined to be adequate for maintenance needs of ewes. / Graduation date: 2002

This study evaluated the effects of tillage system, rotational tillage sequences, and winter seed burial depth on weed seedling recruitment in irrigated cropping systems. Notill (NT) planting of vegetable crops reduced emergence of hairy nightshade by 77 to 99% and Powell amaranth emergence from 50 to 87% compared to conventional tillage (CT) and planting of crops. Cover crops suppressed weed emergence if soils were undisturbed but not if soils were tilled in the spring. Four years of NT vegetable crops reduced summer annual weed density by 48 to 79% at two sites. Rotational tillage sequences that alternated between NT and CT only reduced summer annual weed density if the shorter season crop of snap beans was paired with CT and sweet corn was paired with NT. Hairy nightshade density decreased by 83 to 90% if NT was paired with the longer season crop of sweet corn. Hairy nightshade seedling recruitment at 30.7 C was more than 15 times greater for seeds buried at 6, 13 and 25 cm than when buried at 1 cm in simulated NT. Recruitment potential was low in March and April but increased to a maximum in May and June. Germination rates for seeds buried at 1 cm were lower and mortality and dormancy greater than for seeds buried from 6 to 25 cm during the winter. Protecting the seeds buried at 1 cm from rainfall during the winter increased seedling recruitment from 0 to 2 of 10 buried seeds, but had a negligible effect on seed mortality and dormancy. Treatment of seeds buried at 25 cm with 1 cm soil temperature reduced recruitment from 4.8 to 2.3 of 10 buried seeds at 33.3 C, but did not significantly increase seed mortality or dormancy. Estimates of seed drift using electronic transponders found that 16% of the seeds at 5 cm moved to within the emergence zone for hairy nightshade. Seed drift coupled with the faster germination rate and lower mortality of seeds buried at 12 cm or below predicts that hairy nightshade recruitment will be optimized when soil is tilled in the spring. / Graduation date: 2005

Provoked Vestibulodynia (PVD) is the most common form of chronic vulvar pain, affecting 12% of women in the general population. PVD is characterized by a severe burning pain in response to pressure localized to the vaginal entrance. Research examining the pain component of PVD indicates that it has much in common with other chronic pain conditions. Increased pain sensitivity has been demonstrated in other chronic pain conditions to be due in part to impairment in centrally acting endogenous pain modulation systems, such as Diffuse Noxious Inhibitory Control (DNIC). DNIC is triggered by the simultaneous application of two painful stimuli, with pain at one body site inhibiting pain at another body site. Because DNIC consists of a feedback loop that involves the spinal cord and the brain, it is thought to be dependent upon both sensory and affective pain components. In the current study, 20 women with PVD and 24 controls underwent sensory testing to determine the integrity of DNIC function. Unexpectedly, women with PVD displayed a DNIC response of greater magnitude than controls. Participants also completed measures to assess the interplay between group, DNIC, and psychosocial functioning. Women with PVD experienced decreases in psychosocial functioning; however, this reduction was not found to mediate the relationship between group and DNIC function. Findings of intact DNIC function in women with PVD do not imply that PVD is not a chronic pain condition. DNIC is a complex and dynamic process and warrants further study using different stimuli and paradigms. This study supports previous literature, while adding to the development of a greater understanding of the interaction between psychophysical and psychosocial components of chronic pain, which will allow for the creation of better assessment and treatment strategies. / Thesis (Master, Psychology) -- Queen's University, 2007-09-14 00:14:17.698

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.A.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed Aug. 17, 2007. Includes bibliographical references (p. 70-77).

The application of a sequential test, the sequential probability ratio test, for the tolerances of noxious weed seeds is studied. It is proved that the sequential test can give a similar power curve to that of the current fixed sample test if the test parameters are properly chosen. The average sample size required by a sequential test, in general, is smaller than that of the existing test. However, in some cases it requires relatively a larger sample than current test. As a solution to the problem a method of truncation is considered. A kind of mixed procedure is suggested. This procedure gives almost an identical power curve to the standard one with great savings in sample size. The sample size is always less than that of the current test procedure.

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Thesis (Ph.D.)--Mississippi State University. Department of Biological Sciences. / Title from title screen. Includes bibliographical references.