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P Dodds

Publications and source records attributed to P Dodds.

13 recordsLinked to original sources
PubMed2025

Optimising parent selection in plant breeding: comparing metaheuristic algorithms for genotype building.

Stacking desirable haplotypes across the genome to develop superior genotypes has been implemented in several crop species. A major challenge in Optimal Haplotype Selection is identifying a set of parents that collectively contain all desirable haplotypes, a complex combinatorial problem with countless possibilities. In this study, we evaluated the performance of metaheuristic search algorithms (MSAs)-genetic algorithm (GA), differential evolution (DE), particle swarm optimisation (PSO), and simulated annealing (SA) for optimising parent selection under two genotype building (GB) objectives: Optimal Haplotype Selection (OHS) and Optimal Population Value (OPV). Using a diverse wheat population of 583 lines genotyped for 29,972 SNPs, forming 7645 haplotype blocks and phenotyped for stripe rust scores, we assessed each algorithm's performance across fitness optimisation, convergence speed, and computational efficiency. GA consistently achieved high fitness and rapid convergence, while DE showed robustness but required longer runtime and careful tuning. PSO performed well under the OHS criterion but was less effective for OPV. SA, although computationally lighter, was less consistent in finding optimal solutions. Simulation over 100 breeding cycles showed that OHS outperformed both OPV and GEBV-based selection in long-term genetic gain and diversity retention. OHS maintained heterozygosity and additive variance, which are key for sustainable improvement, while GEBV selection led to early allele fixation. Our findings underscore the potential of GB strategies that prioritise the collective performance of parent sets rather than individual ranking to enhance selection outcomes in genomic-assisted breeding programmes.

Plant Breeding↗
PubMed2002

Formal observations and engagement: a discussion paper.

Formal observation of patients at risk is extremely common in acute psychiatric facilities. Effectively a form of physical containment, observation is resource-intensive, makes significant personal demands upon staff and skews the focus of nursing care towards the small group of patients judged to be most at risk. For patients, the experience of being observed is often less than therapeutic and, in some cases, counter productive. In this paper, the authors draw upon a variety of perspectives, including that of a psychiatrist and a service user. It is argued that the practice of formal observation is ineffective and may actually contribute to the poor state of UK acute psychiatric inpatient units, in terms of direct patient care, clinical decision-making and appropriate risk management. In a recent 'commentary' within this journal, the authors offered 'engagement' as an alternative to observation. In this paper, the meaning of engagement is refined and presented as a process of emotional and psychological containment of distress. The paper concludes that inappropriate over-use of formal observation as a custodial and defensive practice can contribute to a sense of dehumanization and isolation within acute psychiatric patients; engagement may provide a genuine (i.e. not just linguistic) alternative.

Coercion↗
PubMed2000

The generation of plant disease resistance gene specificities.

We are gaining an understanding of the molecular basis of resistance specificity and of the natural processes that generate different specificities. This is a prerequisite for the genetic engineering of new plant disease-resistance genes to control diseases for which naturally occurring resistance is inadequate. DNA sequence analysis indicates that point mutation, recombination and selection can generate and maintain the high levels of polymorphism observed in resistance genes. Comparisons of closely related resistance proteins indicate that specificity can be determined by variation in at least two regions. One of these contains leucine-rich repeats, which are a common feature of most resistance proteins.

Amino Acid Sequence↗
PubMed2000

Structure, function and evolution of plant disease resistance genes.

Gene-for-gene plant disease resistance involves two basic processes: perception of pathogen attack, followed by responses to limit disease. Perception involves receptors with high degrees of specificity for pathogen strains, which are encoded by disease resistance genes. Large repertoires of distantly related resistance (R) genes with diverse recognitional specificities are found within a single plant species. The generation of R-gene polymorphism involves gene duplication, followed by DNA-sequence divergence by point mutation, and by deletion and duplication of intragenic DNA repeats encoding blocks of leucine-rich elements. Recombination between related genes reassorts this variation to further diversify gene sequences. Pathogen pressure selects functional resistance specificities and results in the maintenance of R-gene diversity. Recent genome-sequence data reveal that the NBS-LRR (i.e. nucleotide-binding site-leucine-rich repeat) class of R genes represents as much as 1% of the Arabidopsis genome. Experimental data have shown that the LRR has a role in determination of specificity. Mutation experiments, in which R-gene signaling has been dissociated from specificity in constitutive signal mutants, have provided the potential for non-specific resistance to be expressed from pathogen-infection-induced promoters in transgenic plants.

Evolution, Molecular↗
PubMed1990

Carcinoma of the thyroid gland in Auckland, New Zealand.

We have reviewed the Auckland experience (1969 to 1987) of 212 instances of carcinoma of the thyroid gland. Females outnumbered males by 4:1, the average age of the patients was 46 years and differentiated cancer was more common (180) than either anaplastic (20) or medullary carcinoma (12). The incidence was higher in the Polynesian patients, most of whom were born outside of New Zealand, than in Maori or European patients, most of whom were born in New Zealand. Patients with papillary carcinoma fared well with greater than 90 per cent of the patients alive at the time of the study, while the corresponding figure for follicular carcinoma was 70 per cent. For both types of differentiated carcinoma of the thyroid gland, the best results, in terms of outcome and morbidity, occurred after total ipsilateral lobectomy and partial contralateral lobectomy (TL + CLPL). In neither type of operation was the use of an adjuvant radioiodine therapy of any obvious benefit. The incidence of permanent complications was twice as high after total thyroidectomy than for TL + CLPL. In contrast with the situation regarding adjuvant radioiodine, patients who presented with systemic follicular carcinomatosis responded well to therapeutic radioiodine, and if thyroidectomy could also be accomplished, the outcome was good. Most patients with anaplastic carcinoma presented with unresectable disease and no regimen used made any impact on the biologic factors of the disease. All but one of the patients with medullary carcinoma had the sporadic variant, and the results were similar after performing either unilateral operation or total thyroidectomy. Carcinoma of the thyroid is more common in Polynesians born in Pacific Islands than in Caucasians or Maoris born in New Zealand. For differentiated carcinoma of the thyroid gland, a satisfactory combination of outcome and morbidity is accomplished with TL + CLPL. Although therapeutic radioiodine is effective in patients with metastatic differentiated carcinoma of the thyroid, we could not show that surgical treatment plus adjuvant radioiodine yielded better results than surgical treatment alone. The major prognostic factors governing the outcome were the histologic type (most patients with papillary carcinoma survive; most patients with anaplastic carcinoma die irrespective of treatment, and patients with follicular and medullary lesions have an in-between outlook) and the presence of systemic disease. The presence of regional disease did not appear to influence the outcome.(ABSTRACT TRUNCATED AT 400 WORDS)

Carcinoma↗
PubMed1985

A study of sweat sodium and chloride; criteria for the diagnosis of cystic fibrosis.

Retrospective analysis of sodium and chloride results from sweat tests carried out in Bristol and Sheffield has shown that misdiagnosis of cystic fibrosis (false negatives and false positives) is considerably less if sodium and chloride are both measured. In patients with cystic fibrosis the chloride concentration is usually higher than the sodium, whereas in normal subjects the reverse usually occurs. This observation is particularly useful when borderline results (50-70 mmol/L) are obtained.

Adolescent↗