In the Breckland Environmentally Sensitive Area (ESA), farmers are encouraged to manage arable field margins to conserve arable plant communities using uncropped, cultivated field boundary strips ("uncropped wildlife strips") (UWSs). This study aims to describe the vegetation ofUWSs and to carry out an ecological assessment against the ESA objectives. Data were collected from a sample ofUWS and normally cropped sites in three study areas between 1989 and 1992. Species richness and non-crop biomass were greater in UWS than cropped sites. Bromus sterilis became dominant in study area 1, and appeared to have a competitive effect on other species. In study area 2 cultivations were done less frequently and perennial Graminae spread and became abundant. In study area 3, Amsinckia micrantha showed greatest increase but no effect on other species was apparent. Weed ingress into adjacent crops was lower at UWS than normally cropped sites. ESA objectives were translated into ecological criteria which could be directly measured. Assessments by subjective expert opinion and using species autecological data were compared. Subjective data were collected by a postal questionnaire of experts. Indicator species for each criterion were identified by applying rule sets to a species-attribute matrix. Site values for each criterion were calculated, and overall site values (foci) assigned using a multiple criterion method. Subjective site assessments closely agreed with the site foci and also with three of the five criteria. Over four years, half the sites were above the threshold level which represented satisfying ofESA objectives. Multivariate analysis of variation in the vegetation, from the main dataset and from a second survey, showed sites with lower soil pH, K and total N were more successful. Those with many overhanging or broadleaved trees, or previously cropped with sugar beet were less successful. Some amendments to management prescriptions are recommended.

No description available.

No description available.

Thesis (Ph. D.)--West Virginia University, 2008. / Title from document title page. Document formatted into pages; contains xv, 188 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 172-182).

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 156-161).

Rejection sensitivity is defined as the tendency to expect and look for rejection in ambiguous social situations. Individuals high in rejection sensitivity may interpret ambiguous or benign action to be situations of rejection, which may negatively impact these individuals’ intimate relationships. Research suggests that rejection sensitivity may manifest differently for men and women, such that men are more likely to be jealous and controlling, whereas women are more likely to be unsupportive and hostile. These reactions to ambiguous situations may influence the way rejection sensitive individuals seek help. To our knowledge, there is no research available that examines the link between rejection sensitivity and helpseeking behaviors. Williams and Mickelson (2008) found that stigmatized, low-income women who fear rejection were more likely to engage in indirect help-seeking behavior (e.g., complained about their problems in a general way) than direct help-seeking behavior (e.g., gave details about the problem), which resulted in lower levels of support. However, this one prior study examined only one item of fear of rejection, which actually tapped into worry about the support network not providing support if sought. The current study extended that prior research by examining similar hypotheses except using a more extensive measure of trait rejection sensitivity. Additional outcome variables were tested including anxiety and self esteem. We hypothesized that individuals high in rejection sensitivity would seek help indirectly, which would in turn link with high anxiety and low self-esteem, while those individuals low in rejection sensitivity would seek help directly which would in turn link with low anxiety and high self-esteem. Additionally, we hypothesized that type of help seeking would be related to network response such that indirect help seeking would be related to increased negative network response (e.g., attempt to change the topic) and decreased positive network response (e.g., sympathy), with direct help seeking being related to the inverse. Given the gender differences in experience of rejection sensitivity reported in the literature, these differences were also be explored. The current study was a cross-sectional design, in which participants (N = 381) completed a one-time online survey. The majority of participants were female (68.6%) and Caucasian (90%) with an average age of 20.82. Initial analyses revealed support for the proposed hypotheses. Rejection sensitivity was positively correlated with indirect help seeking (r =.110, p < .05) and negatively correlated with direct help seeking (r = -.133, p < .01). While direct help seeking was positively correlated with positive network response, indirect help seeking was related to both positive network response and negative network response (all ps < .01). Indirect help seeking was also positively correlated with anxiety and negatively correlated with self-esteem (all ps < .01). Findings are consistent with previous work on the negative outcomes among individuals high in rejection sensitivity, and that perhaps in part these individuals behave in ways that foster rejection. The current findings suggest future research should examine the relationship between rejection sensitivity, help seeking, and outcomes using an experimental or longitudinal design in order to capture the temporal ordering of the correlational relations reported here.

This dissertation presents the synthesis of a series of thermo- and pH-sensitive hydrophilic block copolymers and the study of their solution behavior in water. By incorporating a small amount of weak acid or base groups into the thermosensitive block(s) of a hydrophilic block copolymer, the LCST of the thermosensitive block(s) can be modified by changing the solution pH. Accordingly, the critical micellization temperature (CMT) and the sol-gel transition temperature (Tsol-gel) of the block copolymer in water can be tuned. Chapter 1 describes the synthesis of thermo- and pH-sensitive poly(methoxydi(ethylene glycol) methacrylate-co-methacrylic acid)-b-PEO-bpoly( methoxydi(ethylene glycol) methacrylate co-methacrylic acid) and the study of sol-gel transitions of its aqueous solutions at various pH values. The CMT of the 0.2 wt% solution and the Tsol-gel of the 12.0 wt% solution of this copolymer can be varied over a large temperature range. By judiciously controlling temperature and pH, multiple sol-gel-sol transitions were realized. Chapter 2 presents a systematic study of pH effect on rheological properties of micellar gels formed from 10.0 wt% aqueous solutions of thermo- and pH-sensitive poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid)-b-PEO-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid). With the increase of pH, the sol-gel transition became broader. The plateau moduli (GN) evaluated from frequency sweeps at T/Tsol-gel of 1.025, 1.032, and 1.039 decreased with the increase of pH from 3.00 to 5.40 with the largest drop observed at pH = ~ 4.7. The decrease in GN reflects the reduction of the number of bridging chains. The ionization of carboxylic acid introduced charges onto the thermosensitive blocks and made the polymer more hydrophilic, facilitating the formation of loops and dangling chains. Chapter 3 presents the synthesis of PEO-b-poly(methoxydi(ethylene glycol)methacrylate-co-2-(N-methyl-N-(4-pyridyl)amino)ethyl methacrylate) with the thermosensitive block containing a catalytic 4-N,N-dialkylaminopyridine and the study of the effect of thermo-induced micellization on its activity in the hydrolysis of pnitrophenyl acetate. The CMTs of this copolymer at pH of 7.06 and 7.56 were 40 and 37 °C, respectively. Below CMT, the logarithm of initial hydrolysis rate changed linearly with 1/T. Above CMT, the reaction rate leveled off, which is presumably because it was controlled by mass transport to the core of micelles above CMT.

No description available.

No description available.

Thesis (Ph.D.)--McMaster University, 2004. / Supervisor: Robert Pelton. Includes bibliographical references.