3,901 research outputs found
Use of ERTS-1 pictures in coastal oceanography in British Columbia
The ERTS-1 color composite picture of the Vancouver-Victoria region illustrates the value of ERTS data for coastal oceanography. The water of the Fraser River plume which is so clearly visible in the center of the scene has been of interest to oceanographers on the west coast of Canada for a long time as an easily visible tracer of surface water circulation in the strait of Georgia. Maps of the plume at different states of the tide and with different river flow and weather were compiled from oblique aerial photographs in 1950 and used in the siting of sewage and other outfalls in the Vancouver area. More recently high level aerial photomosaics have been used to map the plume area, but the plume can spread over distances of 30 to 40 miles and many photographs, with the uneven illumination inherent in wide angle coverage, are needed for the mosaic. The ERTS satellite gives the first complete view of the plume area. Electronic enhancement of the images shows that the satellite's narrow angle coverage allows very weak surface turbidity features to be made visible to give information on surface currents over a wide area
Reassessment of the evidence for postcranial skeletal pneumaticity in Triassic archosaurs, and the early evolution of the avian respiratory system.
Uniquely among extant vertebrates, birds possess complex respiratory systems characterised by the combination of small, rigid lungs, extensive pulmonary air sacs that possess diverticula that invade (pneumatise) the postcranial skeleton, unidirectional ventilation of the lungs, and efficient crosscurrent gas exchange. Crocodilians, the only other living archosaurs, also possess unidirectional lung ventilation, but lack true air sacs and postcranial skeletal pneumaticity (PSP). PSP can be used to infer the presence of avian-like pulmonary air sacs in several extinct archosaur clades (non-avian theropod dinosaurs, sauropod dinosaurs and pterosaurs). However, the evolution of respiratory systems in other archosaurs, especially in the lineage leading to crocodilians, is poorly documented. Here, we use µCT-scanning to investigate the vertebral anatomy of Triassic archosaur taxa, from both the avian and crocodilian lineages as well as non-archosaurian diapsid outgroups. Our results confirm previous suggestions that unambiguous evidence of PSP (presence of internal pneumatic cavities linked to the exterior by foramina) is found only in bird-line (ornithodiran) archosaurs. We propose that pulmonary air sacs were present in the common ancestor of Ornithodira and may have been subsequently lost or reduced in some members of the clade (notably in ornithischian dinosaurs). The development of these avian-like respiratory features might have been linked to inferred increases in activity levels among ornithodirans. By contrast, no crocodile-line archosaur (pseudosuchian) exhibits evidence for unambiguous PSP, but many of these taxa possess the complex array of vertebral laminae and fossae that always accompany the presence of air sacs in ornithodirans. These laminae and fossae are likely homologous with those in ornithodirans, which suggests the need for further investigation of the hypothesis that a reduced, or non-invasive, system of pulmonary air sacs may be have been present in these taxa (and secondarily lost in extant crocodilians) and was potentially primitive for Archosauria as a whole
Should we be treating animal schistosomiasis in Africa? The need for a One Health economic evaluation of schistosomiasis control in people and their livestock
A One Health economic perspective allows informed decisions to be made regarding control priorities and/or implementation strategies for infectious diseases. Schistosomiasis is a major and highly resilient disease of both humans and livestock. The zoonotic component of transmission in sub-Saharan Africa appears to be more significant than previously assumed, and may thereby affect the recently revised WHO vision to eliminate schistosomiasis as a public health problem by 2025. Moreover, animal schistosomiasis is likely to be a significant cost to affected communities due to its direct and indirect impact on livelihoods. We argue here for a comprehensive evaluation of the economic burden of livestock and zoonotic schistosomiasis in sub-Saharan Africa in order to determine if extending treatment to include animal hosts in a One Health approach is economically, as well as epidemiologically, desirable
Use of an inertial navigation system for accurate track recovery and coastal oceanographic measurements
A data acquisition system using a Litton LTN-51 inertial navigation unit (INU) was tested and used for aircraft track recovery and for location and tracking from the air of targets at sea. The characteristic position drift of the INU is compensated for by sighting landmarks of accurately known position at discrete time intervals using a visual sighting system in the transparent nose of the Beechcraft 18 aircraft used. For an aircraft altitude of about 300 m, theoretical and experimental tests indicate that calculated aircraft and/or target positions obtained from the interpolated INU drift curve will be accurate to within 10 m for landmarks spaced approximately every 15 minutes in time. For applications in coastal oceanography, such as surface current mapping by tracking artificial targets, the system allows a broad area to be covered without use of high altitude photography and its attendant needs for large targets and clear weather
The Development of Statistical Computing at Rothamsted
An account is given of the development of statistical computing at Rothamsted. It is concerned mainly with the period from 1954 (when the first electronic computer was delivered) until 1985 (when this article was written). Initially, many specialised programs were written, but it was soon realised that, for efficiency, general-purpose programs—each unifying many statistical techniques—were required. The development of these programs was gradual and required corresponding developments in statistical theory. Now, the bulk of statistical work, not only for Rothamsted but also for the Agricultural and Food Research Service (AFRS) as a whole, is covered by a few programs, notably Genstat that has an international market. Further developments of these programs are required to make them more accessible to scientists who are not well versed in statistics and to take advantage of technological advances
Discoverability of Private Investigator Surveillance in South Carolina: Navigating the Work Product Doctrine under Samples v. Mitchell
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Black and minority ethnic trainees’ experiences of physical education initial teacher training
The official published version can be accessed at the link below.This report draws together the findings of research that aimed to explore black and minority ethnic (BME) trainees’ experiences of Physical Education (PE) initial teacher training (ITT). Although the numbers of BME trainees opting to enter teaching have improved considerably over the last few years, PE remains one of three specific subject areas where they remain significantly under-represented. Current figures suggest that PE attracts approximately 3% of trainees from BME backgrounds, compared with 11% for new entrants into teaching overall. The relative lack of success in attracting BME trainees into PE teaching compared to other subject areas suggests that the subculture of the subject may be a compounding factor. Over the last decade or so, a number of studies have explored the impact of ethnicity on teachers’ professional socialisation and their experiences as teachers in school, but none have focused on experiences within specific subject cultures. The centrality of the body in PE, and the link between this and the perceived low status of the subject, are influencing factors highlighted in the broader literature, including sports studies. For example, research exploring racism and the under-representation of BME participants in sport has highlighted the prevalence of stereotypical attitudes about their physicality and abilities held by coaches, administrators and spectators. Other research has suggested that some minority ethnic groups favour higher status, better paid, careers in areas such as law or medicine rather than teaching. As yet, there has been little attention to ‘race’ and ethnicity within PEITT, although studies have shown the impact of gender on trainees’ developing professional identities, and how teachers’ gendered bodies are important ‘tools’ of their work. In addition, there has been little research that has acknowledged trainees’ multiple identities, or the complex ways in which ‘race’, ethnicity, class and gender and other identity markers intersect to impact on the professional socialisation process. The research on which this report is based sought to fill some of these gaps in our understandings of BME trainees’ experiences of PEITT, and to identify strategies that might help in their recruitment and retention in the longer term. The research was funded through a small Recruitment and Retention Challenge Grant from the Teacher Development Agency (TDA). These grants form part of the TDA’s wider policy agenda to widen the diversity of new intakes opting into teaching. Higher education institutions have been encouraged, through targets and financial support and incentives, to develop specific strategies aimed at widening the diversity of their cohorts. Examples of such strategies include the provision of specialist admission help for BME prospective trainees; opportunities to gain experience in schools; open days and ‘taster’ events; advertising in the ethnic minority media, and the development of good practice guides and staff training to help ITT providers address issues of ‘race’ and ethnicity. 5 The impetus for this research resulted, in part, from presentations and discussions at a one day PEITT Network1 staff seminar on diversity held in October, 2007. The quantitative research conducted by the Association for Physical Education (AfPE) and the Ethnic Minority Foundation (EMF) presented here, showed the extent of the national under-representation of BME students in PEITT. Although the day focused on addressing reasons for BME under representation and strategies that might be used for improving recruitment, we felt it was also important to learn about the qualitative experiences of trainees that have been attracted into PEITT. Understanding the experiences of our current BME trainees might offer useful insights into how we might recruit and retain future such trainees. Our choice of qualitative research was supported by a national study published shortly after the network day, investigating the links between gender, ethnicity and degree attainment (Higher Education Academy, HEA, 2008), which specifically calls for further qualitative studies of students’ experiences of different subject areas.Funding from the Training and Development Agency (TDA
Black and Minority Ethnic Trainees' Experiences of Physical Education Initial Teacher Training: Report to the Training and Development Agency
Snake mitochondrial genomes: phylogenetic relationships and implications of extended taxon sampling for interpretations of mitogenomic evolution
<p>Abstract</p> <p>Background</p> <p>Snake mitochondrial genomes are of great interest in understanding mitogenomic evolution because of gene duplications and rearrangements and the fast evolutionary rate of their genes compared to other vertebrates. Mitochondrial gene sequences have also played an important role in attempts to resolve the contentious phylogenetic relationships of especially the early divergences among alethinophidian snakes. Two recent innovative studies found dramatic gene- and branch-specific relative acceleration in snake protein-coding gene evolution, particularly along internal branches leading to Serpentes and Alethinophidia. It has been hypothesized that some of these rate shifts are temporally (and possibly causally) associated with control region duplication and/or major changes in ecology and anatomy.</p> <p>Results</p> <p>The near-complete mitochondrial (mt) genomes of three henophidian snakes were sequenced: <it>Anilius scytale</it>, <it>Rhinophis philippinus</it>, and <it>Charina trivirgata</it>. All three genomes share a duplicated control region and translocated tRNA<sup>LEU</sup>, derived features found in all alethinophidian snakes studied to date. The new sequence data were aligned with mt genome data for 21 other species of snakes and used in phylogenetic analyses. Phylogenetic results agreed with many other studies in recovering several robust clades, including Colubroidea, Caenophidia, and Cylindrophiidae+Uropeltidae. Nodes within Henophidia that have been difficult to resolve robustly in previous analyses remained uncompellingly resolved here. Comparisons of relative rates of evolution of rRNA vs. protein-coding genes were conducted by estimating branch lengths across the tree. Our expanded sampling revealed dramatic acceleration along the branch leading to Typhlopidae, particularly long rRNA terminal branches within Scolecophidia, and that most of the dramatic acceleration in protein-coding gene rate along Serpentes and Alethinophidia branches occurred before <it>Anilius </it>diverged from other alethinophidians.</p> <p>Conclusions</p> <p>Mitochondrial gene sequence data alone may not be able to robustly resolve basal divergences among alethinophidian snakes. Taxon sampling plays an important role in identifying mitogenomic evolutionary events within snakes, and in testing hypotheses explaining their origin. Dramatic rate shifts in mitogenomic evolution occur within Scolecophidia as well as Alethinophidia, thus falsifying the hypothesis that these shifts in snakes are associated exclusively with evolution of a non-burrowing lifestyle, macrostomatan feeding ecology and/or duplication of the control region, both restricted to alethinophidians among living snakes.</p
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