Diallel analysis of varying late season night temperatures on the development of a range of fluecured tobacco (Nicotiana tabacum l.) genotypes : a thesis presented in partial fulfillment of the requirements for the degree of Masterate of Agricultural Science in Plant Science at Massey University

Pg 62 not in original - misnumberedA study was conducted in the climate room facilities, at D.S.I.R. Plant Physiology Division, Palmerston North, on the effect of varying late season night temperatures on the development of a range of flue-cured tobacco genotypes. The study involved imposing three night temperatures, 10°C, 15°C and 20°C, when the plants came into flower. Ten F1 genotypes of a five parent diallel cross (no parents, no reciprocals) were grown at each night temperature with three replications per temperature. Fourteen morphological, physical and chemical characters were measured. The effect of late season night temperature was negligible but there was some evidence of genotype environment interaction for some of the characters. The experiment was conducted using single plants as plots and the statistical analysis showed acceptable coefficients of variation for biological studies. The genetic analysis of the diallel showed that general combining ability variance is the most important type of genetic variance in the characters examined. This agrees with the majority of other tobacco diallel studies. As general combining ability variance is largely a measure of additive genetic variance, breeding homozygous lines from a heterozygous base population should be the best approach to follow. Heritability values were of sufficient size for several of the commercially important characters to indicate that improvement through selection was possible. General combining ability and phenotypic simple correlations between pairs of characters were generally in good agreement, demonstrating that phenotypic selection will result in altering the genotypes in the desired direction for the characters in question. The experiment showed a large negative correlation between the two economically important characters, yield and total nicotine alkaloids. This result is in agreement with similar studies carried out by other workers in this field. The experiment revealed a number of improvements which could be useful in the conduct of future tobacco climate room studies

Community screening for preschool child inhibition to offer the 'Cool Little Kids' anxiety prevention programme

Temperamental inhibition has been identified as a key risk factor for childhood anxiety and internalizing problems. An efficacious early prevention programme for shy/inhibited children has been developed; however, accurate, efficient and acceptable screening is needed to support wider implementation. We explore community screening options in the context of a trial implementing the Cool Little Kids prevention programme for anxiety disorders. In comparison to the Australian Temperament Project's inhibition scale, we examine the Strengths and Difficulties Questionnaire's (SDQ) ability to screen for inhibited preschool children. Parents of 6307 children aged 3 to 6years enrolled in preschool programmes from eight socio-economically diverse districts in Melbourne, Australia, first completed the measures of inhibition and SDQ. Parents with inhibited children then enrolled in the Cool Little Kids randomized trial (n=545). Of these, 88% provided feedback about inhibition screening. Parents allocated to the intervention also provided feedback on the Cool Little Kids parenting programme. Results demonstrated that parents of preschool children (i) find inhibition screening acceptable, (ii) take up this parenting programme and (iii) report favourable feedback. The SDQ emotional symptoms subscale demonstrated acceptable sensitivity but insufficient specificity to identify inhibited preschool children. Presenting parents with a brief, validated inhibition scale could be a low-cost option for identifying inhibited preschool children in the community to offer early anxiety prevention.12 page(s

Thalamic Deep Brain Stimulation for Essential Tremor: Relation of the Dentatorubrothalamic Tract with Stimulation Parameters

BACKGROUND: In deep brain stimulation (DBS) for essential tremor, the primary target ventrointermedius (VIM) nucleus cannot be clearly visualized with structural imaging. As such, there has been much interest in the dentatorubrothalamic tract (DRTT) for target localization, but evidence for the DRTT as a putative stimulation target in tremor suppression is lacking. We evaluated proximity of the DRTT in relation to DBS stimulation parameters. METHODS: This is a retrospective analysis of 26 consecutive patients who underwent DBS with microelectrode recordings (46 leads). Fiber tracking was performed with a published deterministic technique. Clinically optimized stimulation parameters were obtained in all patients at the time of most recent follow-up (6.2 months). Volume of tissue activated (VTA) around contacts was calculated from a published model. RESULTS: Tremor severity was reduced in all treated hemispheres, with 70% improvement in the treated hand score of the Clinical Rating Scale for Tremor. At the level of the active contact (2.9 ± 2.0 mm superior to the commissural plane), the center of the DRTT was lateral to the contacts (5.1 ± 2.1 mm). The nearest fibers of the DRTT were 2.4 ± 1.7 mm from the contacts, whereas the radius of the VTA was 2.9 ± 0.7 mm. The VTA overlapped with the DRTT in 77% of active contacts. The distance from active contact to the DRTT was positively correlated with stimulation voltage requirements (Kendall τ = 0.33, P = 0.006), whereas distance to the atlas-based VIM coordinates was not. CONCLUSIONS: Active contacts in proximity to the DRTT had lower voltage requirements. Data from a large cohort provide support for the DRTT as an effective stimulation target for tremor control

Focused Ultrasound Thalamotomy with Dentato-Rubro-Thalamic Tractography in Patients with Spinal Cord Stimulators and Cardiac Pacemakers

Magnetic resonance image-guided high-intensity focused ultrasound (MRgFUS)-based thermal ablation of the ventral intermediate nucleus of the thalamus (VIM) is a minimally invasive treatment modality for essential tremor (ET). Dentato-rubro-thalamic tractography (DRTT) is becoming increasingly popular for direct targeting of the presumed VIM ablation focus. It is currently unclear if patients with implanted pulse generators (IPGs) can safely undergo MRgFUS ablation and reliably acquire DRTT suitable for direct targeting. We present an 80-year-old male with a spinal cord stimulator (SCS) and an 88-year-old male with a cardiac pacemaker who both underwent MRgFUS for medically refractory ET. Clinical outcomes were measured using the Clinical Rating Scale for Tremor (CRST). DRTT was successfully created and imaging parameter adjustments did not result in any delay in procedural time in either case. In the first case, 7 therapeutic sonications were delivered. The patient improved immediately and durably with a 90% CRST-disability improvement at 6-week follow-up. In our second case, 6 therapeutic sonications were delivered with durable, 75% CRST-disability improvement at 6 weeks. These are the first cases of MRgFUS thalamotomy in patients with IPGs. DRTT targeting and MRgFUS-based thermal ablation can be safely performed in these patients using a 1.5-T MRI