Contrasting genetic diversity among Oryza longistaminata (A. Chev et Roehr) populations from different geographic origins using AFLP

Molecular markers have been used extensively in studying genetic diversity, genetic relationships and germplasm management. However, the understanding of between and within population genetic variation and how it is partitioned on the basis of geographic origin is crucial as this helps to improve sampling efficiency. The objective of this study was therefore to assess the intra-specific diversity in Oryza longistaminata and how the variation is partitioned within and between different geographic locations, using molecular markers. AFLP analysis generated 176 bands that revealed high levels of polymorphism (95.6%) and diversity within and between populations. The mean Nei's genetic diversity for all the 176 loci in the 48 populations was 0.302 and diversity for populations within countries ranged from 0.1161 to 0.2126. Partitioning of between and within population diversity revealed that the mean allelic diversity at each polymorphic locus was HT = 0.3445. The within population diversity was (HS = 0.1755) and the between population diversity was (DST = 0.1688). Results of AMOVA revealed significant differences (

Defining and identifying crop landraces

Awareness of the need for biodiversity conservation is now universally accepted, but most often recent conservation activities have focused on wild species. Crop species and the diversity between and within them has significant socioeconomic as well as heritage value. The bulk of genetic diversity in domesticated species is located in traditional varieties maintained by traditional farming systems. These traditional varieties, commonly referred to as landraces, are severely threatened by genetic extinction primarily due to their replacement by modern genetically uniform varieties. The conservation of landrace diversity has been hindered in part by the lack of an accepted definition to define the entity universally recognized as landraces. Without a definition it would be impossible to prepare an inventory and without an inventory changes in landrace constituency could not be recognized over time. Therefore, based on a literature review, workshop discussion and interviews with key informants, common characteristics of landraces were identified, such as: historical origin, high genetic diversity, local genetic adaptation, recognizable identity, lack of formal genetic improvement, and whether associated with traditional farming systems. However, although these characteristics are commonly present they are not always all present for any individual landrace; several crop-specific exceptions were noted relating to crop propagation method (sexual or asexual), breeding system (self-fertilized or cross-fertilized species), length of formal crop improvement, seed management (selection or random propagation) and use. This paper discusses the characteristics that generally constitute a landrace, reviews the exceptions to these characteristics and provides a working definition of a landrace. The working definition proposed is as follows: `a landrace is a dynamic population(s) of a cultivated plant that has historical origin, distinct identity and lacks formal crop improvement, as well as often being genetically diverse, locally adapted and associated with traditional farming systems

The genetic structure and conservation of aus, aman and boro rices from

Abstract A diverse set of 115 rice varieties from Bangladesh was surveyed using 35 polymorphic RAPD (randomly amplified polymorphic DNA) markers and the genetic structure of this germplasm, encompassing the principal rice ecotypes of Bangladesh (aus, aman and boro), was determined using multivariate analysis. The level of genetic diversity was evaluated and compared with the levels of diversity found within other rice growing areas of the world. Geographical information systems analysis using Atlas-GIS was employed to analyse and present the geographic distribution of genetic diversity across Bangladesh, and cluster analysis was used to test the efficiency of selection of material for a core collection

Lower limb stiffness and maximal sprint speed in 11-16-year-old boys

The purpose of the study was to examine the relationship between vertical stiffness, leg stiffness and maximal sprint speed in a large cohort of 11-16-year-old boys. Three-hundred and thirty-six boys undertook a 30 m sprint test using a floor-level optical measurement system, positioned in the final 15 m section. Measures of speed, step length, step frequency, contact time and flight time were directly measured whilst force, displacement, vertical stiffness and leg stiffness, were modeled from contact and flight times, from the two fastest consecutive steps for each participant over two trials. All force, displacement and stiffness variables were significantly correlated with maximal sprint speed (p 0.7) relationship with sprint speed, while vertical center of mass displacement, absolute vertical stiffness, relative peak force, and maximal leg spring displacement had large (r > 0.5) relationships. Relative vertical stiffness and relative peak force did not significantly change with advancing age (p > 0.05), but together with maximal leg spring displacement accounted for 96% of the variance in maximal speed. It appears that relative vertical stiffness and relative peak force are important determinants of sprint speed in boys aged 11-16 years, but are qualities that may need to be trained due to no apparent increases from natural development. Practitioners may wish to utilize training modalities such as plyometrics and resistance training to enable adaptation to these qualities due to their importance as predictors of speed in youth

Recent Advances in Graph Partitioning

We survey recent trends in practical algorithms for balanced graph partitioning together with applications and future research directions

The Expanding Fireball of Nova Delphini 2013

A classical nova occurs when material accreting onto the surface of a white dwarf in a close binary system ignites in a thermonuclear runaway. Complex structures observed in the ejecta at late stages could result from interactions with the companion during the common envelope phase. Alternatively, the explosion could be intrinsically bipolar, resulting from a localized ignition on the surface of the white dwarf or as a consequence of rotational distortion. Studying the structure of novae during the earliest phases is challenging because of the high spatial resolution needed to measure their small sizes. Here we report near-infrared interferometric measurements of the angular size of Nova Delphini 2013, starting from one day after the explosion and continuing with extensive time coverage during the first 43 days. Changes in the apparent expansion rate can be explained by an explosion model consisting of an optically thick core surrounded by a diffuse envelope. The optical depth of the ejected material changes as it expands. We detect an ellipticity in the light distribution, suggesting a prolate or bipolar structure that develops as early as the second day. Combining the angular expansion rate with radial velocity measurements, we derive a geometric distance to the nova of 4.54 +/- 0.59 kpc from the Sun.Comment: Published in Nature. 32 pages. Final version available at http://www.nature.com/nature/journal/v515/n7526/full/nature13834.htm

Decoherence, einselection, and the quantum origins of the classical

Decoherence is caused by the interaction with the environment. Environment monitors certain observables of the system, destroying interference between the pointer states corresponding to their eigenvalues. This leads to environment-induced superselection or einselection, a quantum process associated with selective loss of information. Einselected pointer states are stable. They can retain correlations with the rest of the Universe in spite of the environment. Einselection enforces classicality by imposing an effective ban on the vast majority of the Hilbert space, eliminating especially the flagrantly non-local "Schr\"odinger cat" states. Classical structure of phase space emerges from the quantum Hilbert space in the appropriate macroscopic limit: Combination of einselection with dynamics leads to the idealizations of a point and of a classical trajectory. In measurements, einselection replaces quantum entanglement between the apparatus and the measured system with the classical correlation.Comment: Final version of the review, with brutally compressed figures. Apart from the changes introduced in the editorial process the text is identical with that in the Rev. Mod. Phys. July issue. Also available from http://www.vjquantuminfo.or

Evaluation of an inter-professional workshop to develop a psychosocial assessment and child-centred communication training programme for paediatricians in training

BACKGROUND: The quality of psychosocial assessment of children in consultations varies widely. One reason for this difference is the variability in effective mental health and communication training at undergraduate and post-qualification levels. In recognition of this problem, the Royal College of Paediatrics and Child Health in the United Kingdom have developed the Child in Mind Project that aims to meet this deficit in medical training. This paper describes the evaluation of a workshop that explored the experiences and expectations of health care professionals in the development of a training programme for doctors. METHODS: The one-day inter-professional workshop was attended by 63 participants who were invited to complete evaluation forms before and immediately after the workshop. RESULTS: The results showed that the workshop was partially successful in providing an opportunity for an inter-professional group to exchange ideas and influence the development of a significant project. Exploring the content and process of the proposed training programme and the opportunity for participants to share experiences of effective practice were valued. Participants identified that the current culture within many health care settings would be an obstacle to successful implementation of a training programme. Working within existing training structures will be essential. Areas for improvement in the workshop included clearer statement of goals at the outset and a more suitable environment for the numbers of participants. CONCLUSIONS: The participants made a valuable contribution to the development of the training programme identifying specific challenges. Inter-professional collaborations are likely to result in more deliverable and relevant training programmes. Continued consultation with potential users of the programme – both trainers and trainees will be essential