The Effects of Cytokinin on the Transcriptional Regulation of PIN Expression in Arabidopsis thaliana

The processes of cell division and differentiation are critical to the development of any multicellular organism. During the formation of plant roots these processes take place at a region of the root tip called the meristem. Cytokinin and auxin are two plant growth hormones that influence this process. Although these two growth hormones are both necessary they also appear in many ways to have an antagonistic relationship. As meristematic root cells undergo differentiation they cease dividing. It has been proposed that the size of the root meristem and thus the overall rate of root growth are determined by the balance between the rate of cell division, determined by auxin, and the rate of cell differentiation, determined by cytokinin. One of the ways cytokinin may have an antagonistic influence on auxin regulation is by limiting auxin transport. Directed auxin transport from one part of a plant to another is controlled by a family of auxin efflux proteins called PIN proteins. To date, studies reported in the literate are inconsistent as to whether and how cytokinin influences PIN protein production at the transcriptional and/or translational level. This study was undertaken to explore the effect of cytokinin signaling on PIN gene expression using real-time quantitative PCR

Foraging ecology of common dolphins (Delphinus sp.) in the Hauraki Gulf, New Zealand : a thesis presented in fulfilment of the requirements for the degree of Master of Science (Zoology), Massey University, Albany, New Zealand

This study investigated the foraging ecology of common dolphins (Delphinus sp.) in the Hauraki Gulf Marine Park, off the east coast of Auckland. New Zealand. Like most species of small cetacea in the Southern Hemisphere, its foraging habits are poorly described. A total of 59 focal group follows of common dolphins were conducted between January and April 2006. Observations were conducted at the surface, recording the predominant behavioural state of the group, foraging phase, foraging strategy, group dispersion, group formation, swimming style, group heading, calf presence and associated species. All occurrences of fission-fusion events and surface behaviours were recorded. This study tested the hypothesis that foraging behaviour of common dolphins would be influenced by environmental and physical parameters, group size, calf presence and associations with other species. In the Hauraki Gulf, foraging behaviour was recorded during all common dolphin follows, with 14% ± 1.7 (mean ± s.e.) of time spent feeding. Larger groups of dolphins spent more time foraging than smaller groups. Herding accounted for a large part of the foraging behaviour of common dolphins (mean ± s.e. = 28% ± 2.3. n = 54). Larger groups were found to spend significantly more time herding than smaller groups. Herding was generally directed towards the nearest landmass. Common dolphins use a variety of foraging strategies, both individual and group coordinated strategies. High-speed pursuits (n = 29) and kerplunkmg (n= 15) were the only individual foraging strategies recorded. Coordinated feeding strategies employed were synchronous diving (n = 50), Ime-abreast (n = 28), carouselling (n = 26) and wall-formation (n = 4). Synchronous diving and carouselling were the most enduring strategies, accounting for a significant proportion of foraging behaviour (mean ± s.e. - 32% ± 0.05 and 24% ± 0.08 of instantaneous samples, respectively). Foraging strategies were typified by vanous group formations, dispersion between group members, swimming styles and breathing intervals. Foraging strategies were also observed to have different roles in dolphin foraging. Line-abreast and wall- formation were associated with herding. However, high-speed pursuit, kerplunking and carouselling were strategies synonymous with feeding. Foraging strategies were shown to be dynamic, with dolphin groups changing strategies within a foraging bout (mean ± s.e. = 3 ± 0.4). Larger groups spent more time engaged in coordinated foraging strategies than smaller groups. Noisy surface behaviours and fission-fusion events were frequently seen in synchrony with foraging behaviour. Calves present in a foraging group, typically assumed a central position in the group during herding, but remained on the periphery during feeding. When feeding, common dolphins frequently were associated with Australasian gannets (Morus senator), shearwaters (Puffinus spp.) and Bryde's whales (Balaenoptera brydei) Observations on the predatory behaviour of each species suggested a temporary close association between birds, whales and dolphins. This study showed an association of Australasian gannet flocks (n =46) and Bryde's whales (n = 27) with common dolphins, and described the nature of the joint aggregations of mixed-species feeding in the Hauraki Gulf. The behaviour of gannots and whales strongly coincided with that of the foraging dolphin group. Whales were recorded tracking behind foraging dolphins for up to one and a half hours (mean ± s.e. = 23 min ± 2.3). Observations suggest that the relationship between gannets and whales with common dolphins was deliberate, and that these species take advantage of the superior ability of dolphins to locate and concentrate prey. The associations with gannets and whales had a significant impact on common dolphin foraging behaviour. Duration of the phenomenon was predicted to be a direct function of the quantity of prey fish available. The presence of a whale had a sizable impact on the diffusion of feeding aggregations. Results from this study indicate that the benefits of coordinated team hunts implemented by common dolphins in the Hauraki Gulf are a key factor in their foraging ecology. Their cooperative foraging skills appear to not only benefit the common dolphin individual, but other species as well. Ultimately, their role as a social hunter and an abundant, apex predator in the ocean, suggests that the common dolphin is a strongly interacting species which may facilitate population viability of other species in the Hauraki Gulf ecosystem

Think Again: The Decision Making Process in \u3ci\u3eKing Lear\u3c/i\u3e and Jane Smiley\u27s \u3ci\u3eA Thousand Acres\u3c/i\u3e

This thesis is a feminist reading of Shakespeare‟s King Lear and Jane Smiley‟s Pulitzer Prize winning novel A Thousand Acres that applies psychological insights into human behavior to explain economic decision-making. Many of the traditional readings of King Lear, including the works of critics A. C. Bradley, Maynard Mack and Stephen Greenblatt, approach the play by accepting the patriarchal view of Lear as the rightful ruler, while Goneril and Regan are wicked for taking the kingdom from their father. Smiley‟s A Thousand Acres, however, approaches the text from what she imagines Goneril‟s perspective to be and includes the incestuous implications of a relationship in which daughters love their father all. While both approaches are valid, I examined economic decisions the daughters make when Lear offers his daughters his kingdom and Larry offers his daughters the farm. These economic decisions reflect the psychological theories into how people decide, and I apply these theories to show both Lear and his daughters basing their understanding of economic gain on heuristics of cognitive ease, availability, and the anchoring power of the patriarch rather than Platonic rationality. This, then, frees Lear from his monstrous position in Smiley‟s novel and Goneril and Regan‟s wicked roles in King Lear, and allows for a reading of the plot that is rooted in the psychological depth of all human life. Lear, Goneril, Regan and Cordelia all make effective and ineffective, positive and destructive, emotional and rational decisions throughout the play making it impossible to simplify each character as simply legitimate or wicked, sinned against or sinning

A Correlational Analysis of Empowerment and Experience with Resistance to Change

Despite more than 60 years of research about the nature of change, resistance to change remains a problem across industries. Health care leaders have limited knowledge of how health care managers\u27 perceptions of empowerment, years of experience, and resistance to change (RTC) relate. The purpose for this nonexperimental correlational study was to examine the relationship between empowerment, years of experience, and RTC among managers via an online survey. The theoretical framework incorporated Kanter\u27s structural empowerment theory and Kotter\u27s change theory. The sample included 245 out of 1,181 health care managers from Veterans Administration (VA) hospitals in the New York metropolitan region, recruited through a nonrandom purposive sampling method. There was a significant association measured between empowerment and RTC (r = -.132, p = .05), but no association between years of experience and RTC (r = .060, p =.348). The regression model showed that years of experience and perceptions of empowerment together in one model was not a significant predictor of RTC (F(2,242) =2.82, p = .062, R2 = .023). In the model, perceptions of empowerment was a statistically significant predictor of RTC (â = -.136, p = .03), but years of managerial experience was not (â = .074, p = .249). These findings, while not generalizable, offer a unique examination of organizational change among an underexamined population. According to study results, as empowerment increased, RTC diminished. In contrast, experience did not relate to the propensity to resist change. These findings have social implications for VA and general business leaders who may use these results to improve change management plans, empower staff, reduce RTC, and enhance organizational and patient outcomes

Maternity Rights and Mothers' Return to Work

In this paper we use the ALSPAC cohort of 12,000 births to examine the effect of maternity rights on mothers' post-birth return to employment decisions. We aim to disentangle the effects of the terms of maternity rights entitlements from the effects of other factors (such as household wealth, personal preferences and labour market opportunities) that influence the timing of a mother's return to work. We adopt a discrete hazard model with instrumental variables to estimate a counterfactual of what mothers with rights would have done in the absence of this legislation. Mothers with rights have an underlying (but unobserved) stronger attachment to the labour market which prompts earlier return than on average. Nevertheless, even when we take this into account we find a substantial impact of maternity rights on behaviour. Having rights induces around 20 per cent more women to return to their previous job before 7 months than would otherwise be the case. Women from lower skilled groups return disproportionately at the date at which maternity pay expires, while managerial and professional women tend to return at the expiry of unpaid leave.government policy, welfare, child care, labor supply

The emergence of resistance to the benzimidazole anthlemintics in parasitic nematodes of livestock is characterised by multiple independent hard and soft selective sweeps

Anthelmintic resistance is a major problem for the control of parasitic nematodes of livestock and of growing concern for human parasite control. However, there is little understanding of how resistance arises and spreads or of the “genetic signature” of selection for this group of important pathogens. We have investigated these questions in the system for which anthelmintic resistance is most advanced; benzimidazole resistance in the sheep parasites Haemonchus contortus and Teladorsagia circumcincta. Population genetic analysis with neutral microsatellite markers reveals that T. circumcincta has higher genetic diversity but lower genetic differentiation between farms than H. contortus in the UK. We propose that this is due to epidemiological differences between the two parasites resulting in greater seasonal bottlenecking of H. contortus. There is a remarkably high level of resistance haplotype diversity in both parasites compared with drug resistance studies in other eukaryotic systems. Our analysis suggests a minimum of four independent origins of resistance mutations on just seven farms for H. contortus, and even more for T. circumincta. Both hard and soft selective sweeps have occurred with striking differences between individual farms. The sweeps are generally softer for T. circumcincta than H. contortus, consistent with its higher level of genetic diversity and consequent greater availability of new mutations. We propose a model in which multiple independent resistance mutations recurrently arise and spread by migration to explain the widespread occurrence of resistance in these parasites. Finally, in spite of the complex haplotypic diversity, we show that selection can be detected at the target locus using simple measures of genetic diversity and departures from neutrality. This work has important implications for the application of genome-wide approaches to identify new anthelmintic resistance loci and the likelihood of anthelmintic resistance emerging as selection pressure is increased in human soil-transmitted nematodes by community wide treatment programs

Phytoplankton Dynamics in Galveston Bay: Assessing Responses to Freshwater Inflows

Increased freshwater use in estuarine watersheds is a concern for productivity downstream in ecologically and economically important estuaries worldwide. In Galveston Bay (TX), the seventh largest estuary in the United States, population growth in two large metropolitan areas (Houston and Dallas-Fort Worth), continues to alter the quantity and quality of freshwater inflows (FWI). We report here on the influence of FWI on pelagic and benthic phytoplankton in Galveston Bay in spring and summer over 3 years (2010 to 2012), intended to capture periods of high and low FWI, respectively. A year of severe drought that persisted throughout 2011 allowed us to also examine consequences of prolonged low flows. We followed the response of pelagic phytoplankton (biomass, community composition) to the addition of nutrients using assays, and the response of benthic phytoplankton (biomass, community composition), in addition to corresponding nutrient fluxes and sediment oxygen consumption via core incubation methods. Log response ratios indicated bay-wide nitrate+ammonium (NA) and nitrate+phosphate (NP) co-limitation of pelagic phytoplankton, in addition to recurrent N or A limitation. Further, nutrient limitation of phytoplankton standing stock was more frequently observed during drought than non-drought years. Diatoms, cyanobacteria, and chlorophytes were dominant in 2010 and 2011, but dinoflagellates became particularly prominent in spring 2012 as FWI alleviated prolonged drought conditions. We also observed resilience of the benthic microalgal (BMA) community to drought, but not in the benthic boundary layer (BBL) phytoplankton community. BMA communities primarily consisted of diatoms throughout, while BBL phytoplankton communities differed with each sampling event. Fluxes differed before and after the drought, and the results here imply that resilience of the water column system is at risk in future drought events, though further study is necessary. We observed that drought itself does not have a significant effect on pelagic or benthic phytoplankton community composition, though timing of the beginning of the drought in relation to annual phytoplankton growth cycles could play a role. Rather, the increase in availability of freshwater inflows following the drought appeared to be more influential on community structure, than the lack of inflows and the resources they bring