1,551 research outputs found
Study of the Hindrance Effect in Sub-barrier Fusion Reactions
We have measured the fusion cross sections of the 12C(13C, p)24Na reaction
through off-line measurement of the beta-decay of 24Na using the beta-gamma
coincidence method. Our new measurements in the energy range of Ec.m. = 2.6-3.0
MeV do not show an obvious S-factor maximum but a plateau. Comparison between
this work and various models is presented.Comment: 3 pages, 3 figures, Talk at the "10th International Conference on
Nucleus-Nucleus Collisions", Beijing, 16-21 August 200
Perceived importance of components of asynchronous music in circuit training
This study examined regular exercisers’ perceptions of specific components of music
during circuit training. Twenty-four men (38.8 years, s = 11.8 years) and 31 women
(32.4 years, s = 9.6 years) completed two questionnaires immediately after a circuit
training class. Participants rated the importance of 13 components of music (rhythm,
melody, etc.) in relation to exercise enjoyment, and each completed the Affect Intensity
Measure (Larsen, 1984) to measure emotional reactivity. Independent t tests were used
to evaluate gender differences in perceptions of musical importance. Pearson
correlations were computed to evaluate the relationships between affect intensity, age
and importance of musical components. Consistent with previous research and
theoretical predictions, rhythm response components (rhythm, tempo, beat) were rated
as most important. Women rated the importance of melody significantly higher than did
men, while men gave more importance to music associated with sport. Affect intensity
was found to be positively and significantly related to the perceived importance of
melody, lyrical content, musical style, personal associations and emotional content.
Results suggest that exercise leaders need to be sensitive to personal factors when
choosing music to accompany exercise. Qualitative research that focuses on the
personal meaning of music is encouraged
Protocol of a natural experiment to evaluate a supermarket intervention to improve food purchasing and dietary behaviours of women (WRAPPED study) in England: a prospective matched controlled cluster design
Introduction: Poor diet is a leading risk factor for non-communicable diseases and costs the National Health Service £5.8 billion annually. Product placement strategies used extensively in food outlets, like supermarkets, can influence customers’ preferences. Policy-makers, including the UK Government, are considering legislation to ensure placement strategies promote healthier food purchasing and dietary habits. High-quality scientific evidence is needed to inform future policy action. This study will assess whether healthier placement strategies in supermarkets improve household purchasing patterns and the diets of more than one household member.
Methods and analyses: This natural experiment, with a prospective matched controlled cluster design, is set in discount supermarkets across England. The primary objective is to investigate whether enhanced placement of fresh fruit and vegetables improves household-level purchasing of these products after 6 months. Secondary objectives will examine: (1) differences in intervention effects on purchasing by level of educational attainment, (2) intervention effects on the dietary quality of women and their young children, (3) intervention effects on store-level sales of fruit and vegetables and (4) cost-effectiveness of the intervention from individual, retailer and societal perspectives. Up to 810 intervention and 810 control participants will be recruited from 18 intervention and 18 matched control stores. Eligible participants will be women aged 18–45 years, who hold a loyalty card and shop in a study store. Each control store will be matched to an intervention store on: (1) sales profile, (2) neighbourhood deprivation and (3) customer profile. A detailed process evaluation will assess intervention implementation, mechanisms of impact and, social and environmental contexts.
Ethics and dissemination: Ethical approval was obtained from the University of Southampton, Faculty of Medicine Ethics Committee (ID 20986.A5). Primary, secondary and process evaluation results will be submitted for publication in peer-reviewed scientific journals and shared with policy-makers.
Trial registration number: NCT03573973; Pre-results
Anarchy in the UK: Detailed genetic analysis of worker reproduction in a naturally occurring British anarchistic honeybee, Apis mellifera, colony using DNA microsatellites
Anarchistic behaviour is a very rare phenotype of honeybee colonies. In an anarchistic colony,
many workers’ sons are reared in the presence of the queen. Anarchy has previously
been described in only two Australian colonies. Here we report on a first detailed genetic
analysis of a British anarchistic colony. Male pupae were present in great abundance above
the queen excluder, which was clearly indicative of extensive worker reproduction and is the
hallmark of anarchy. Seventeen microsatellite loci were used to analyse these male pupae,
allowing us to address whether all the males were indeed workers’ sons, and how many
worker patrilines and individual workers produced them. In the sample, 95 of 96 of the
males were definitely workers’ sons. Given that
≈
1% of workers’ sons were genetically
indistinguishable from queen’s sons, this suggests that workers do not move any
queen-laid eggs between the part of the colony where the queen is present to the area above
the queen excluder which the queen cannot enter. The colony had 16 patrilines, with an
effective number of patrilines of 9.85. The 75 males that could be assigned with certainty to
a patriline came from 7 patrilines, with an effective number of 4.21. They were the offspring of at least 19 workers. This is in contrast to the two previously studied Australian naturally occurring anarchist colonies, in which most of the workers’ sons were offspring of one patriline. The high number of patrilines producing males leads to a low mean relatedness between laying workers and males of the colony. We discuss the importance of studying such colonies in the understanding of worker policing and its evolution
Local lattice disorder in the geometrically-frustrated spin glass pyrochlore Y2Mo2O7
The geometrically-frustrated spin glass Y2Mo2O7 has been considered widely to
be crystallographically ordered with a unique nearest neighbor magnetic
exchange interaction, J. To test this assertion, we present x-ray-absorption
fine-structure results for the Mo and Y K edges as a function of temperature
and compare them to results from a well-ordered pyrochlore, Tl2Mn2O7. We find
that the Mo-Mo pair distances are significantly disordered at approximately
right angles to the Y-Mo pairs. These results strongly suggest that lattice
disorder nucleates the spin-glass phase in this material.Comment: 9 pages, 2 Postscript figures, Phys. Rev. B: Rapid, in pres
Why do some social insect queens mate with several males? Testing the sex-ratio manipulation hypothesis in Lasius niger
Although multiple mating most likely increases mortality risk for social insect queens and lowers the kin benefits for nonreproductive workers, a significant proportion of hymenopteran queens mate with several males. It has been suggested that queens may mate multiply as a means to manipulate sex ratios to their advantage. Multiple paternity reduces the extreme relatedness value of females for workers, selecting for workers to invest more in males. In populations with female-biased sex ratios, queens heading such male-producing colonies would achieve a higher fitness. We tested this hypothesis in a Swiss and a Swedish population of the ant Lasius niger. There was substantial and consistent variation in queen mating frequency and colony sex allocation within and among populations, but no evidence that workers regulated sex allocation in response to queen mating frequency; the investment in females did not differ among paternity classes. Moreover, population-mean sex ratios were consistently less female biased than expected under worker control and were close to the queen optimum. Queens therefore had no incentive to manipulate sex ratios because their fitness did not depend on the sex ratio of their colony. Thus, we found no evidence that the sex-ratio manipulation theory can explain the evolution and maintenance of multiple mating in L. niger
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