Enhancement of germination of spores of Verticillium dahliae and Fusarium oxysporum esp vasinfectum in vascular fluid from cotton plants infected with the root-knot nematode

Root-knot nematode [RKN] (Meloidogyne incognita) can increase the severity of Verticillium (V dahliae) and Fusarium (F oxysporum f.sp. vasinfectum) wilt diseases in cotton (Gossypium hirsutum). This study was conducted to determine some of the physiological responses caused by nematode invasion that might decrease resistance to vascular wilt diseases. The effect of RKN was investigated on spore germination and protein, carbohydrate and peroxidase content in the xylem fluids extracted from nematode-infected plants. Two cotton cultivars were used with different levels of resistance to both of the wilt pathogens. Spore germination was greater in the xylem fluids from nematode-infected plants than from nematode-free plants. The effect on spore germination was greater in the Fusarium-resistant cultivar (51%). Analysis of these fluids showed a decrease in total protein and carbohydrate levels for both wilt-resistant cultivars, and an increase in peroxidase concentration. Fluids from nematode-free plants of the Verticillium-resistant cultivar contained 46% more peroxidase than the Fusarium-resistant cultivar. The results provide further evidence that the effect of RKN on vascular wilt resistance is systemic and not only local. Changes in metabolites in the xylem pass from the root to the stem, accelerating disease development.

Ecophysiology of seed dormancy and the control of germination in early spring-flowering Galanthus nivalis and Narcissus pseudonarcissus (Amaryllidaceae)

Seed dormancy induction and alleviation in the winter-flowering moist temperate woodland species Galanthus nivalis and Narcissus pseudonarcissus are complex and poorly understood. Temperature, light and desiccation were investigated to elucidate their role in the germination ecophysiology of these species. Outdoor and laboratory experiments simulating different seasonal temperatures, seasonal durations, and temperature fluctuations; the presence of light during different seasons; and intermittent drying (during the summer period) over several ‘years’ investigated the importance of these factors in germination. Warm summer-like temperatures (20°C) were necessary for germination at subsequent cooler autumn-like temperatures (greatest at 15°C in G. nivalis and 10°C in N. pseudonarcissus). As the warm temperature duration increased so did germination at subsequent cooler temperatures; further germination occurred in subsequent ‘years’ at cooler temperatures following a second, and also third, warm period. Germination was significantly greater in darkness, particularly in G. nivalis. Dormancy increased with seed maturation period in G. nivalis, because seeds extracted from green capsules germinated more readily than those from yellow. Desiccation increased dormancy in an increasing proportion of N. pseudonarcissus seeds the later they were dried in ‘summer’. Seed viability was only slightly reduced by desiccation in N. pseudonarcissus but was poor and variable in G. nivalis. Shoot formation occurred both at the temperature at which germination was greatest and also if 5°C cooler. In summary, continuous hydration of seeds of both species during warm summer-like temperatures results in the gradual release of seed dormancy; thereafter, darkness and cooler temperatures promote germination. Cold temperatures, increased seed maturity (G. nivalis), and desiccation (N. pseudonarcissus) increase dormancy while light inhibits germination.

On the speed of the eddy-driven jet and the width of the Hadley cell in the Southern Hemisphere

A strong correlation between the speed of the eddy-driven jet and the width of the Hadley cell is found to exist in the Southern Hemisphere, both in reanalysis data and in twenty-first-century integrations from the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report multimodel archive. Analysis of the space–time spectra of eddy momentum flux reveals that variations in eddy-driven jet speed are related to changes in the mean phase speed of midlatitude eddies. An increase in eddy phase speeds induces a poleward shift of the critical latitudes and a poleward expansion of the region of subtropical wave breaking. The associated changes in eddy momentum flux convergence are balanced by anomalous meridional winds consistent with a wider Hadley cell. At the same time, faster eddies are also associated with a strengthened poleward eddy momentum flux, sustaining a stronger westerly jet in midlatitudes. The proposed mechanism is consistent with the seasonal dependence of the interannual variability of the Hadley cell width and appears to explain at least part of the projected twenty-first-century trends.

The Optimal trigger speed of vehicle activated signs

The thesis aims to elaborate on the optimum trigger speed for Vehicle Activated Signs (VAS) and to study the effectiveness of VAS trigger speed on drivers’ behaviour. Vehicle activated signs (VAS) are speed warning signs that are activated by individual vehicle when the driver exceeds a speed threshold. The threshold, which triggers the VAS, is commonly based on a driver speed, and accordingly, is called a trigger speed. At present, the trigger speed activating the VAS is usually set to a constant value and does not consider the fact that an optimal trigger speed might exist. The optimal trigger speed significantly impacts driver behaviour. In order to be able to fulfil the aims of this thesis, systematic vehicle speed data were collected from field experiments that utilized Doppler radar. Further calibration methods for the radar used in the experiment have been developed and evaluated to provide accurate data for the experiment. The calibration method was bidirectional; consisting of data cleaning and data reconstruction. The data cleaning calibration had a superior performance than the calibration based on the reconstructed data. To study the effectiveness of trigger speed on driver behaviour, the collected data were analysed by both descriptive and inferential statistics. Both descriptive and inferential statistics showed that the change in trigger speed had an effect on vehicle mean speed and on vehicle standard deviation of the mean speed. When the trigger speed was set near the speed limit, the standard deviation was high. Therefore, the choice of trigger speed cannot be based solely on the speed limit at the proposed VAS location. The optimal trigger speeds for VAS were not considered in previous studies. As well, the relationship between the trigger value and its consequences under different conditions were not clearly stated. The finding from this thesis is that the optimal trigger speed should be primarily based on lowering the standard deviation rather than lowering the mean speed of vehicles. Furthermore, the optimal trigger speed should be set near the 85th percentile speed, with the goal of lowering the standard deviation.

Speed of adjustment within currency markets

One measure of market efficiency is the speed at which prices adjust to fundamental value with the arrival of information. This paper examines this issue by estimating speed of adjustment coefficients using three  methodologies for eight currencies for the entire year of 1996 using half hourly non-overlapping return intervals. We find that the bulk of adjustment to fundamental value for all currencies occurs within the hour but then quickly deteriorates. Within the hour adjustment is sufficiently quick to be considered efficient but the lack of full adjustment to fundamental value is not what would be predicted within an efficient market. There is no evidence for any of the currencies studied of a tendency to over react. There is also little difference in the speeds of adjustment between actively and less actively traded  currencies. There is however a definite difference in the speed at which currencies adjustment depending on whether they are free floating or managed exchange rates. Free floating rates adjust much quicker. Government intervention slows adjustment to fundamental value.

Do organizational service recovery actions impact on hotel guests future intentions and does speed of recovery matter?

This paper investigates hotel guests’ responses to organizational actions dealing with service failure. Eight service failure scenarios were used to identify guests’ intentions towards future visits. Guests’ intentions to switch hotels, revisit the property and remain loyal to the chain were found to vary based on the recovery efforts undertaken. This research found that empowering employees contribute to positive consumer intentions toward the service provider. Compensation was also found effective if offered through empowered employees. Speed of response to service failure was also identified as important action to improve consumer future intentions. Based on these findings, implications for future research are highlighted. Recommendations to the practitioners of hospitality and tourism sector were made for the management of failed service encounter.

Role of organizational service recovery actions on sustomer switching intentions in a process based service failure : does speed of recovery matters?

The study examines how organizational activities of compensation and empowerment impact on consumers switching intentions and also whether these differ based on the speed of service recovery. Data is collected using hypothetical scenarios in a situation of process failure. It is found that there is no direct effect of either compensation or empowerment on switching intent, although the interaction effect is significant when recovery occurs quickly.

Faster than the speed of white (noise): potential pressure points in research partnerships and processes

White noise occurs in the thinking, decision making and communication of dominant Settler cultures. It inhibits clear reception of messages, somewhat like the indistinct, fuzzy static of an un-tuned radio. As much a systemic issue as an individual one, it results from assumed privilege and lack of knowledge of worldviews other than the dominant. Until white noise is acknowledged, development of partnerships between Indigenous and non-Indigenous groups is likely to be limited by having to continually start at a point of inequality where nonIndigenous gaps in knowledge and understanding remain unrecognised. This paper/workshop considers challenges encountered while researching experiences of Aboriginal education in Western Australian prisons. Each pressure point occurred where the dominant world view prevailed without question. Discussion will focus on the specific pressure points of ethics approval, project development, informed consent and application of outcomes and findings. The paper asks the questions ‘Who decides what stories are created at these pressure points? What informs those stories?’ As individuals, we might not be able to crash through the white noise barrier but we can chip away and be transparent about its existence with the goal of eventually moving faster than the speed of white (noise).