The placement, fate and effectiveness of granular nematicides in potato beds infested with the potato cyst nematode <i>Globodera pallida</i> (stone)

The chemical control of the potato cyst nematode (PCN) by granular nematicides when applied and incorporated into potato seed beds was investigated to assess problems connected with incorporation using bed cultivation machinery. Fluorescent tracer granule work using a range of granular nematicide incorporation methods suggested that differences exist between the incorporation methods in terms of placement of the fluorescent granules in the planted potato bed. Incorporation of tracer initially by a bed tiller followed by a second incorporation by a stone and clod separator produced a distribution of tracer greater than 40cm deep in the planted bed. Incorporation of tracer by a stone and clod separator with application of tracer halfway up the first web produced concentrated bands of tracer in the sides of the planted bed. No visible differences in tracer distribution occurred between other treatments. The differences observed between incorporation techniques during the fluorescent tracer granule work were shown not to be important in terms of PCN control or yield in the first year's field experiments. The second year of field experimentsa ssessedth e incorporation of the granular nematicide Vydate (10G) before, during or after stone and clod separation of potato beds. These field experiments suggested that timing of nematicide incorporation in relation to stone and clod separation had no effect on potato yield or control of PCN. As in the first year's experiments, significant differences occurred between plots treated or not treated with a granular nematicide, but not between incorporation methods. Work describing the field concentration of oxamyl immediately after planting showed similarities to the distribution of tracer granules observed in the soil hall studies. The subsequent distribution of oxamyl 3 weeks after planting showed no redistribution of the nematicide in the potato bed. The depth of potato planting is thought to be responsible for the uniformity of PCN control and crop response to nematicide treatment regardless of incorporation method as seed was planted below the nematicide treated layer. Evaluation of a diagnostic kit used for detecting oxamyl in soil showed that the kit was well suited for this purpose and its use is discussed in the light of the findings of this study

ANALYSIS AND SIMULATION OF ACTIVE VIBRATION DAMPENING USING CON-STRAINED MODAL SPACE OPTIMAL CONTROL APPROACH

The active vibration attenuation of linearly elastic structures modeled by the finite element method, with a possibly large number of degrees of freedom, is considered. The approach, formulated in modal space, applies mathematical optimization to obtain exact solutions to systems that may involve any number of modes to be controlled by an equal or smaller number of discrete actuators. Such systems are under-actuated and generally involve second-order non-holonomic constraints that impose limitations on the dynamically admissible motions that the system can be made to follow. The approach presented in this thesis has value as a tool for the designing and analyzing active vibration attenuation in structures under idealized conditions, but does not replace traditional control approaches are necessary for practical implementation of such systems. The optimal attenuation of the structure subject to any initial disturbance is obtained by applying Pontryagin’s principle to solve for the minimum solution to a quadratic performance index subject to additional under-actuated constraints that are satisfied by the introduction of time-dependant Lagrange multipliers. The optimality conditions are derived in a compact form and solved by applying symbolic differential operators. The approach uses commercial finite element analysis software and symbolic mathematical software to obtain the optimal actuation forces required by each discrete actuator and the trajectory that the system will undergo. The approach, which is called the constrained modal space optimal control method involves three primary stages in the solution process. The first stage –the structural stage – involves the transformation of any system modeled by finite elements into a sufficient number of modal variables and selection of the number and positioning of potential actuator locations. In this stage any problems with poor controllability can be quickly assessed and mitigated prior to proceeding with the next solution stage – the control stage. In the control stage the optimal control problem is solved and all unknown system forces and trajectories are obtained. System gains for the closed loop system can also be obtained in this stage. In the third stage – the verification stage – the actuation forces obtained in the control stage are tested on a transient time-integrated finite element model to evaluate if the system will respond as expected. Any potential spillover effects on higher modes of vibration not considered in the control can be observed in the verification stage

Researching disabled children and young people’s views on decision-making: working reflexively to rethink vulnerability

Issues relating to qualitative research with disabled children and young people will be discussed. Semi-structured interviews with boys who have Duchenne muscular dystrophy were conducted to explore their thoughts on how they might make a decision to take part in medical research. Assumptions about disabled children’s vulnerability can impact how researchers conduct qualitative research, and how they are involved in significant decision-making. Working reflexively and in partnership with children illustrates their competence, supporting reconsideration of their vulnerability

Committed to burnout: An investigation into the relationship between sport commitment and athlete burnout in Gaelic games players

This study examined the relationship between sports commitment, outlined in the hierarchical Sport Commitment Model, and athlete burnout in men and women playing Gaelic games, for the first time. These athletes experience a number of unique challenges, including playing with numerous teams simultaneously, significant personal commitment despite their amateur status, and the societal and cultural importance of their sports. This study also involved piloting a novel commitment measure of ‘team importance’ for team-sport athletes. Two-hundred-and-one male and female Gaelic games players completed the Sports Commitment Questionnaire, team importance measure and Athlete Burnout Questionnaire. Hierarchical Multiple Regression analyses revealed a negative relationship between sport enjoyment, social support (emotional) and desire to excel and particular burnout components; a positive relationship between other priorities and personal investments and particular burnout components; and enthusiastic commitment was associated with lower burnout, while constrained commitment was linked to higher burnout. The team importance measure was also found to be a reliable and valid measure of sports commitment. These findings provide important insight into how sports commitment can contribute to, or guard against, burnout in male and female athletes

Near-inertial wave scattering by random flows

The impact of a turbulent flow on wind-driven oceanic near-inertial waves is examined using a linearised shallow-water model of the mixed layer. Modelling the flow as a homogeneous and stationary random process with spatial scales comparable to the wavelengths, we derive a transport (or kinetic) equation governing wave-energy transfers in both physical and spectral spaces. This equation describes the scattering of the waves by the flow which results in a redistribution of energy between waves with the same frequency (or, equivalently, with the same wavenumber) and, for isotropic flows, in the isotropisation of the wave field. The time scales for the scattering and isotropisation are obtained explicitly and found to be of the order of tens of days for typical oceanic parameters. The predictions inferred from the transport equation are confirmed by a series of numerical simulations. Two situations in which near-inertial waves are strongly influenced by flow scattering are investigated through dedicated nonlinear shallow-water simulations. In the first, a wavepacket propagating equatorwards as a result from the $\beta$-effect is shown to be slowed down and dispersed both zonally and meridionally by scattering. In the second, waves generated by moving cyclones are shown to be strongly disturbed by scattering, leading again to an increased dispersion.Comment: Accepted for publication in Phys. Rev. Fluid

Phosphorylation by Akt within the ST loop of AMPK-α1 down-regulates its activation in tumour cells

The insulin/IGF-1 (insulin-like growth factor 1)-activated protein kinase Akt (also known as protein kinase B) phosphorylates Ser(487) in the ‘ST loop’ (serine/threonine-rich loop) within the C-terminal domain of AMPK-α1 (AMP-activated protein kinase-α1), leading to inhibition of phosphorylation by upstream kinases at the activating site, Thr(172). Surprisingly, the equivalent site on AMPK-α2, Ser(491), is not an Akt target and is modified instead by autophosphorylation. Stimulation of HEK (human embryonic kidney)-293 cells with IGF-1 caused reduced subsequent Thr(172) phosphorylation and activation of AMPK-α1 in response to the activator A769662 and the Ca(2+) ionophore A23187, effects we show to be dependent on Akt activation and Ser(487) phosphorylation. Consistent with this, in three PTEN (phosphatase and tensin homologue deleted on chromosome 10)-null tumour cell lines (in which the lipid phosphatase PTEN that normally restrains the Akt pathway is absent and Akt is thus hyperactivated), AMPK was resistant to activation by A769662. However, full AMPK activation could be restored by pharmacological inhibition of Akt, or by re-expression of active PTEN. We also show that inhibition of Thr(172) phosphorylation is due to interaction of the phosphorylated ST loop with basic side chains within the αC-helix of the kinase domain. Our findings reveal that a previously unrecognized effect of hyperactivation of Akt in tumour cells is to restrain activation of the LKB1 (liver kinase B1)–AMPK pathway, which would otherwise inhibit cell growth and proliferation

Metabolic and cardiovascular improvements after biliopancreatic diversion in a severely obese patient

BACKGROUND: Severe obesity is associated with important morbidity and increased mortality. The successes of lifestyle modifications and drug therapy have been partial and mostly unsustained in reducing obesity and its comorbidities. Bariatric surgery, particularly biliopancreatic diversion with duodenal switch reduces efficiently excess body weight and improves metabolic and cardiovascular functions. CASE PRESENTATION: A 56-year-old man with severe clinical obesity underwent a biliopancreatic diversion with a duodenal switch after unsuccessful treatment with weight loss pharmacotherapy. He had diabetes, hypertension and sleep apnea syndrome and was on three medications for hypertension and two hypoglycemic agents in addition to > 200 insulin units daily. Eleven months after the surgery, he had lost 40% of his body weight. The lipid profile showed great improvement and the hypertension and diabetes were more easily controlled with no more insulin needed. The pseudonormalized pattern of left ventricular diastolic function improved and ventricular walls showed decreased thickness. CONCLUSION: Biliopancreatic diversion may bring metabolic and cardiovascular benefits in severely obese patients from a cardiovascular perspective

Understanding mobile VLE usage in distance education: A pilot study

This paper presents preliminary results of a mobile virtual learning environment (VLE) usage study conducted at a United Kingdom (UK) based distance education institution. A total of 207 undergraduate students participated in the study over a period of 6 months. Study participants were recruited through email invitation. An online survey was conducted to gather both quantitative and qualitative data about (i) learner characteristics, (ii) awareness about the existence of the mobile VLE system, (iii) perceptions about the usefulness of using the mobile VLE system to support learning, (iv) attitudes towards using mobile VLE technological tools to support learner activities, and (v) motives for using mobile VLE tools when carrying out learning activities. Results indicate that perceived usefulness of the various technological tools incorporated in the mobile VLE system and also familiarity with their usage in teaching and learning has an effect on their deployment in distance education. These findings confirm our assumptions that the design and integration of mobile VLE in teaching and learning should be closely aligned with pedagogical goals and established practices