Do forage legumes have a role in modern dairy farming systems?

peer-reviewedIntensification in New Zealand dairy farming systems has placed greater pressure on clover performance and fitness and has highlighted the need to develop clover cultivars that are better adapted to intensive grazing systems. Increased stocking rates and increased use of nitrogen fertiliser have put enormous pressure on the contribution of clover to modern dairy systems. Future innovations such as semi-hybrid cultivars offer the potential to improve the competitiveness of legumes with nitrogen-fertilised forage grasses. Similarly, advances in condensed tannin research suggest that significant animal performance gains can be achieved in conjunction with reduced environmental impact. In order to capture these benefits, dairy farmers will need to reassess their grazing management to ensure that legumes can be maintained at economically useful levels. Novel grazing management systems that optimise the benefits provided by the grass and legume components need to be used in future dairy farming systems. Forage legumes, and especially white clover, have an important role to play in modern dairy systems

Emigration and the age profile of retirement among immigrants

This paper analyzes the relationship between immigrants’ retirement status and the prevalence of return migration from the host country to their country of origin. We develop a simple theoretical model to illustrate that under reasonable conditions the probability of return migration is maximized at retirement. Reduced-form models of retirement status which control for the rate of return migration are then estimated using unique data on emigration rates matched to individual-level data for Australia. We find that immigrants, particularly immigrant women, are more likely to be retired than are native-born men and women with the same demographic, human capital, and family characteristics. Moreover, within the immigrant population, there is a negative relationship between the propensity to be retired and the return migration rate of one’s fellow countrymen, particularly amongst men. This link is strongest for those individuals who are at (or near) retirement age and among those with the highest cost of return migration. These results suggest that the fiscal pressures associated with aging immigrant populations vary substantially across origin countries

Accuracy of adults’ recall of childhood social class: findings from the Aberdeen children of the 1950s study

<b>Background</b>: Although adult reported childhood socioeconomic position has been related to health outcomes in many studies, little is known about the validity of such distantly recalled information. This study evaluated the validity of adults’ reports of childhood paternal social class. <b>Methods</b>: Data are drawn from the Aberdeen children of the 1950s study, a cohort of 12 150 people born in Aberdeen (Scotland) who took part in a school based survey in 1962. In this survey, two indices of early life socioeconomic position were collected: occupational social class at birth (abstracted from maternity records) and occupational social class in childhood (reported during the 1962 survey by the study participants). Between 2000 and 2003, a questionnaire was mailed to traced middle aged cohort members in which inquiries were made about their fathers’ occupation when they were aged 12 years. The level of agreement between these reports and prospectively collected data on occupational social class was assessed. <b>Results</b>: In total, 7183 (63.7%) persons responded to the mid-life questionnaire. Agreement was moderate between social class of father recalled in adulthood and that measured in early life ( statistics were 0.47 for social class measured at birth, and 0.56 for social class reported by the child). The relation of occupational social class to birth weight and childhood intelligence was in the expected directions, although weaker for adults’ reports in comparison with prospectively gathered data. <b>Conclusions</b>: In studies of adult disease aetiology, associations between childhood social class based on adult recall of parental occupation and health outcomes are likely to underestimate real effects

Distribution, Characteristics, and Use of Earth Dens and Related Excavations by Polar Bears on the Western Hudson Bay Lowlands

Polar bears fasting on land along the western coast of Hudson Bay during the open water period, from late July through early November, excavate three different types of structures, which we termed pits, deep dens, and shallow dens. Pits were shallow excavations found on the tops of banks or beach ridges, whereas both deep and shallow dens were dug into frozen peat banks. Pits were used as temporary resting places. The function of shallow dens is less clear, although some bears have been observed resting in them. Deep dens, which have an entrance tunnel and an enlarged inner chamber, are similar in size and structure to maternity dens dug in snow by female poplar bears elsewhere in their range. Deep and shallow dens are primarily occupied by lone females, most of which are pregnant, while pits are generally occupied by adult males and are used more during summer than in autumn. Pregnant polar bears in western Hudson Bay give birth between mid-November and mid-December, by which time snowdrifts suitable for the construction of maternity dens have not yet formed in most years. Thus, because earth dens represent the only consistently suitable environment available at the time of parturition, we suggest most cubs in western Hudson Bay are born in them. Consequently, the availability of suitable habitat for the construction and use of earth dens is probably critical to the survival of the polar bear population in Western Hudson Bay. Secondary benefits of earth dens to pregnant females, and to other bears during the warm weather in late summer, are that they help the bears to conserve energy by remaining cool and to avoid insect harassment.Les ours polaires qui jeûnent sur la terre ferme le long de la côte occidentale de la baie d'Hudson durant la période d'eau libre (fin juillet à début novembre), creusent trois types de structures différentes que nous appelons fosses, tanières profondes et tanières peu profondes. Les fosses sont des creux peu profonds que l'on a trouvé en haut des talus ou des crêtes de plage, alors que les tanières profondes et peu profondes étaient creusées dans de la tourbe gelée. Les fosses étaient utilisées comme lieux de repos temporaires. La fonction que remplissaient les tanières peu profondes n'est pas claire, bien qu'on y ait observé des ours qui s'y reposaient. Les tanières profondes, qui ont une entrée en forme de tunnel s'élargissant en une chambre intérieure, sont semblables, par leur dimension et leur forme, aux tanières de mise bas creusées dans la neige par les ourses polaires ailleurs dans leur territoire. Les tanières profondes et peu profondes sont surtout occupées par les femelles solitaires, dont la plupart sont pleines, tandis que les fosses sont en général occupées par des mâles adultes et sont plus utilisées en été qu'en automne. Dans la baie d'Hudson occidentale, les ourses pleines mettent bas entre la mi-novembre et la mi-décembre, date à laquelle, la majorité des années, les bancs de neige propres à la construction de tanières de mise bas ne sont pas encore formés. Par conséquent, vu que les tanières dans la terre représentent le seul milieu convenable régulièrement disponible au moment de la parturition, on suggère que, dans la baie d'Hudson occidentale, la plupart des oursons y naissent. La disponibilité d'un habitat approprié à la construction et l'utilisation des tanières de terre est donc probablement critique à la survie de la population de l'ours polaire dans la baie d'Hudson occidentale. Un autre bénéfice que représentent les tanières de terre pour les femelles pleines, ainsi que pour les autres ours durant la saison chaude à la fin de l'été, est que ces tanières aident les ours à conserver leur énergie en les maintenant au frais et à les mettant à l'abri des insectes

Enabling a High Throughput Real Time Data Pipeline for a Large Radio Telescope Array with GPUs

The Murchison Widefield Array (MWA) is a next-generation radio telescope currently under construction in the remote Western Australia Outback. Raw data will be generated continuously at 5GiB/s, grouped into 8s cadences. This high throughput motivates the development of on-site, real time processing and reduction in preference to archiving, transport and off-line processing. Each batch of 8s data must be completely reduced before the next batch arrives. Maintaining real time operation will require a sustained performance of around 2.5TFLOP/s (including convolutions, FFTs, interpolations and matrix multiplications). We describe a scalable heterogeneous computing pipeline implementation, exploiting both the high computing density and FLOP-per-Watt ratio of modern GPUs. The architecture is highly parallel within and across nodes, with all major processing elements performed by GPUs. Necessary scatter-gather operations along the pipeline are loosely synchronized between the nodes hosting the GPUs. The MWA will be a frontier scientific instrument and a pathfinder for planned peta- and exascale facilities.Comment: Version accepted by Comp. Phys. Com

Sen and the art of educational maintenance: evidencing a capability, as opposed to an effectiveness, approach to schooling

There are few more widely applied terms in common parlance than ‘capability’. It is used (inaccurately) to represent everything from the aspiration to provide opportunity to notions of innate academic ability, with everything in between claiming apostolic succession to Amartya Sen, who (with apologies to Aristotle) first developed the concept. This paper attempts to warrant an adaptation of Sen’s capability theory to schooling and schooling policy, and to proof his concepts in the new setting using research involving 100 pupils from 5 English secondary schools and a schedule of questions derived from the capability literature. The findings suggest that a capability approach can provide an alternative to the dominant Benthamite school effectiveness paradigm, and can offer a sound theoretical framework for understanding better the assumed relationship between schooling and well-being