Therapeutic radiographers' perceptions of the barriers and enablers to effective smoking cessation support

Introduction: Tobacco smoking during and post radiotherapy is associated with increased treatment toxicity and increased cancer related mortality. Routine delivery of smoking cessation advice is inconsistent in practice. This study identifies the key barriers and facilitators to the provision of effective smoking cessation conversations in radiotherapy practice. Methods: A baseline questionnaire (n ¼ 43) was used to identify current practice, barriers and facilitators to smoking cessation in radiotherapy and to inform a topic guide for follow up focus groups (n ¼ 5). Ethical approval was obtained through the 4 NHS trusts and the Health Research Authority. Focus group transcription was coded by two researchers. Results: Therapeutic Radiographers initiate health behaviour conversations with patients; there are a number of factors that facilitate the likelihood of a health behaviour conversation; indication that a patient smokes anatomical site and presence of acute effects. Key barriers to smoking cessation provision include; lack of training, limited knowledge, limitations as a result of poor clinical infrastructure, local culture and perceptions that patients do not prioritise smoking cessation during treatment. Conclusion: Therapeutic Radiographers have the motivation to provide smoking cessation advice, however they require further training to develop knowledge and skills in relation to benefits of smoking cessation and cessation strategies. Therapeutic Radiographers also expect that patients will respond negatively to smoking cessation advice, and that this might be damaging to the therapeutic relationship. Departmental culture and trust infrastructure can also significantly inhibit the provision of smoking cessation in radiotherapy practice and further support to implement NICE guidance is required

Kinetic theory of age-structured stochastic birth-death processes

Classical age-structured mass-action models such as the McKendrick-von Foerster equation have been extensively studied but are unable to describe stochastic fluctuations or population-size-dependent birth and death rates. Stochastic theories that treat semi-Markov age-dependent processes using, e.g., the Bellman-Harris equation do not resolve a population's age structure and are unable to quantify population-size dependencies. Conversely, current theories that include size-dependent population dynamics (e.g., mathematical models that include carrying capacity such as the logistic equation) cannot be easily extended to take into account age-dependent birth and death rates. In this paper, we present a systematic derivation of a new, fully stochastic kinetic theory for interacting age-structured populations. By defining multiparticle probability density functions, we derive a hierarchy of kinetic equations for the stochastic evolution of an aging population undergoing birth and death. We show that the fully stochastic age-dependent birth-death process precludes factorization of the corresponding probability densities, which then must be solved by using a Bogoliubov-–Born–-Green–-Kirkwood-–Yvon-like hierarchy. Explicit solutions are derived in three limits: no birth, no death, and steady state. These are then compared with their corresponding mean-field results. Our results generalize both deterministic models and existing master equation approaches by providing an intuitive and efficient way to simultaneously model age- and population-dependent stochastic dynamics applicable to the study of demography, stem cell dynamics, and disease evolution

Recombination dramatically speeds up evolution of finite populations

We study the role of recombination, as practiced by genetically-competent bacteria, in speeding up Darwinian evolution. This is done by adding a new process to a previously-studied Markov model of evolution on a smooth fitness landscape; this new process allows alleles to be exchanged with those in the surrounding medium. Our results, both numerical and analytic, indicate that for a wide range of intermediate population sizes, recombination dramatically speeds up the evolutionary advance

Maximum principle and mutation thresholds for four-letter sequence evolution

A four-state mutation-selection model for the evolution of populations of DNA-sequences is investigated with particular interest in the phenomenon of error thresholds. The mutation model considered is the Kimura 3ST mutation scheme, fitness functions, which determine the selection process, come from the permutation-invariant class. Error thresholds can be found for various fitness functions, the phase diagrams are more interesting than for equivalent two-state models. Results for (small) finite sequence lengths are compared with those for infinite sequence length, obtained via a maximum principle that is equivalent to the principle of minimal free energy in physics.Comment: 25 pages, 16 figure

X Linkage of AP3A, a Homolog of the Y-Linked MADS-Box Gene AP3Y in Silene latifolia and S. dioica

Background: The duplication of autosomal genes onto the Y chromosome may be an important element in the evolution of sexual dimorphism.A previous cytological study reported on a putative example of such a duplication event in a dioecious tribe of Silene (Caryophyllaceae): it was inferred that the Y-linked MADS-box gene AP3Y originated from a duplication of the reportedly autosomal orthologAP3A. However, a recent study, also using cytological methods, indicated that AP3A is X-linked in Silenelatifolia. Methodology/Principal Findings: In this study, we hybridized S. latifolia and S. dioicato investigate whether the pattern of X linkage is consistent among distinct populations, occurs in both species, and is robust to genetic methods. We found inheritance patterns indicative of X linkage of AP3A in widely distributed populations of both species. Conclusions/Significance: X linkage ofAP3A and Y linkage of AP3Yin both species indicates that the genes ’ ancestral progenitor resided on the autosomes that gave rise to the sex chromosomesand that neither gene has moved between chromosomes since species divergence.Consequently, our results do not support the contention that inter-chromosomal gene transfer occurred in the evolution of SlAP3Y from SlAP3A

Developmental appropriateness of kindergarten programs and academic outcomes in first grade

This study explored the relationship between the developmental appropriateness of kindergarten classroom instruction and first-grade report card grade overall averages and averages in reading, language, spelling, math, science, and social studies. The interactive roles that gender, SES, and kindergarten classroom type play in children’s later achievement were also examined. The sample consisted of166first-grade children who hadattended kindergarten classrooms with teaching practices identified as predominately developmentally appropriate or developmentally inappropriate. Findings indicated that firstgraders from more appropriate kindergarten classrooms had higher reading averages than children from less appropriate kindergarten classrooms. Females had higher overall and subject area averages than males. Significant interaction effects indicated that high SES children from less appropriate kindergarten classrooms hadhigheroverall averages and higher averages in all subjects except reading, when compared with low SES children from less appropriate classrooms. Low SES children from more appropriate kindergarten classrooms had higher overall averages and higher averages in all subjects except reading when comparedwith low SES children from less appropriate kindergarten classrooms. No significant differences were found between high and low SES children from more appropriate kindergarten classrooms. © 1993 Taylor & Francis Group, LLC

Inferring Deleterious-Mutation Parameters in Natural Daphnia Populations

Deng and Lynch (1, 2) proposed to characterize deleterious genomic mutations from changes in the mean and genetic variance of fitness traits upon selfing in outcrossing populations. Such observations can be readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. A significant inbreeding depression and an increase of genetic variance for all traits analyzed were observed. Deng and Lynch's (2) procedures were employed to estimate the genomic mutation rate (U), mean dominance coefficient ( [Image: see text] ), mean selection coefficient ( [Image: see text] ), and scaled genomic mutational variance ( [Image: see text] ). On average, [Image: see text] , [Image: see text] , [Image: see text] and [Image: see text] (^ indicates an estimate) are 0.84, 0.30, 0.14 and 4.6E-4 respectively. For the true values, the [Image: see text] and [Image: see text] are lower bounds, and [Image: see text] and [Image: see text] upper bounds

Strong polarization-induced reduction of addition energies in single-molecule nanojunctions

We address polarization-induced renormalization of molecular levels in solid-state based single-molecule transistors and focus on an organic conjugate molecule where a surprisingly large reduction of the addition energy has been observed. We have developed a scheme that combines a self-consistent solution of a quantum chemical calculation with a realistic description of the screening environment. Our results indeed show a large reduction, and we explain this to be a consequence of both (a) a reduction of the electrostatic molecular charging energy and (b) polarization induced level shifts of the HOMO and LUMO levels. Finally, we calculate the charge stability diagram and explain at a qualitative level general features observed experimentally.Comment: 9 pages, 5 figure

Rapid divergence and expansion of the X chromosome in papaya

X chromosomes have long been thought to conserve the structure and gene content of the ancestral autosome from which the sex chromosomes evolved. We compared the recently evolved papaya sex chromosomes with a homologous autosome of a close relative, the monoecious Vasconcellea monoica, to infer changes since recombination stopped between the papaya sex chromosomes. We sequenced 12 V. monoica bacterial artificial chromosomes, 11 corresponding to the papaya X-specific region, and 1 to a papaya autosomal region. The combined V. monoica X-orthologous sequences are much shorter (1.10 Mb) than the corresponding papaya region (2.56 Mb). Given that the V. monoica genome is 41% larger than that of papaya, this finding suggests considerable expansion of the papaya X; expansion is supported by a higher repetitive sequence content of the X compared with the papaya autosomal sequence. The alignable regions include 27 transcript-encoding sequences, only 6 of which are functional X/V. monoica gene pairs. Sequence divergence from the V. monoica orthologs is almost identical for papaya X and Y alleles; the Carica-Vasconcellea split therefore occurred before the papaya sex chromosomes stopped recombining, making V. monoica a suitable outgroup for inferring changes in papaya sex chromosomes. The papaya X and the hermaphrodite-specific region of the Y(h) chromosome and V. monoica have all gained and lost genes, including a surprising amount of changes in the X