2,577 research outputs found

    The Asymmetric Rotor. IX. The Heavy Water Bands at 2787 cm^–1 and 5373 cm^–1

    Get PDF
    The combination band (110) of the two stretching fundamentals of D2O is reported and analyzed to yield nu0=5373.2 cm^–1 and the excited state moments of inertia 1.910, 3.931, and 5.929×10^–40 g cm^2. The same method of analysis applied to the unsymmetrical fundamental band (100) envelope gives nu0=2787.5 cm^–1 and the excited state moments 1.881, 3.876, and 5.843×10^–40 g cm^2

    Can the mid-Holocene provide suitable models for rewilding the landscape in Britain?

    Get PDF
    Palaeoecologists have been encouraging us to think about the relevance of the Holocene fossil record for nature conservation for many years (e.g. Buckland 1993) but this information seems slow to filter through to the conservation community. Indeed, Willis et al. (2005) report that recently published biodiversity reports and policy documents rarely look back more than 50 years and may ignore the historical context entirely. This has been a lost opportunity for understanding ecological systems. Many natural processes occur over timescales that confound our attempts to understand them, so the vast temporal perspective provided by palaeoecological studies can provide important guidance for nature conservation (Willis & Birks 2006). However, accurate vegetation mapping is difficult enough in modern landscapes (Cherrill & McLean 1999), so the challenge of describing prehistoric environments is immeasurably greater. Nevertheless, pioneering work in the mid 20th century showed that pollen and spores extracted from peat bogs were so perfectly preserved thatthey could be used to demonstrate sequences of vegetation change since the last glaciation (Godwin 1956). Since then, the science has burgeoned: ancient deposits of beetles, snails, fungal spores and plant macrofossils add to the picture, as does the chemistry of ancient lake sediments (Bell & Walker 2004). Many questions still remain to be answered by this fascinating research and one aspect has received considerable attention in the last decade. This concerns the nature of the ‘primeval’ landscapes, in other words our understanding of natural systems prior to significant human impact. The debate was kindled by a thesis by the Dutch forest ecologist Frans Vera in 2000 (see also Vera & Buissink 2007). Vera effectively challenged established views about the primeval landscapes and argued that the refutation, and the resulting alternative landscape models, had critical importance for modern conservation practice. Vera’s thesis is focused on the pre-Neolithic (ca 8000-5000bp) landscape in the lowlands of central and western Europe, with the assumption that this period represents an almost pristine or ‘natural’ state which should provide a suitable conservation benchmark. Vera contends (i) that this landscape was not closed woodland but a relatively open park-like mosaic of wood and grassland,and (ii) that large wild herbivores were an essential driving force behind woodland-grassland vegetation cycles. The advocacy in his argument and the timing of the publication, when grazingwas seen as increasingly important in conservation in Europe, have combined to raise the profile of this issue. If Vera is correct, the open park-like landscapes were inherited rather than created by people; this may have implications for conservation practice in Europe. The adoption of Vera’s ideas into conservation management plans in the UK (see Box 1) gives an indication of the influence that this work has had. Indeed, Vera’s ideas have been described as a ‘challenge to orthodox thinking’ (Miller 2002) and considerable debate has been stimulated centering on the ecological validity of Vera’s hypothesis and its relevance for modern conservation. In this article, we attempt to address these issues on the basis of results from a literature review, web-debate and discussions with Dutch and British ecologists, prepared for English Nature with a view to informing conservation strategies (Hodder & Bullock 2005a)

    Multidisciplinary Safety Team (MDST) Factors of Success

    Get PDF
    This project included a literature review and summary that focused on subjects related to team building, team/committee member motivational strategies, and tools for effective and efficient committee meetings. It also completed an online survey of multidisciplinary safety team (MDST) members that focused on methods to increase meeting attendance and the identification of factors that make MDSTs successful. The survey had a response rate of about 15 percent. Finally, three small MDST focus groups were held and the participants discussed information similar to that investigated by the online survey. The results of these three activities were similar and complementary. In general, the outcomes of all three tasks show that a well-designed agenda that has items relevant to the meeting attendees is very important. In addition, the literature, online survey, and focus group results identified other characteristics that define a good team or MDST. Some of these characteristics included effective and consistent leadership, members that are allowed to provide input and have an impact, members that are vested in the activities of the group, and a match between the interests of the members and the focus/mission/purpose of the meetings/group. Meetings that are scheduled well in advance of the meeting date, include time for networking, local safety activity discussions, hands-on activities/tasks, and/or some type of educational or informational presentation or activity also appeared to be the most desirable. Lastly, it was shown that MDSTs can thrive and be successful through various means, but the ability to focus on a specific safety issue when the group is first organized was suggested as a benefit that could be of assistance for long-term sustainability

    Computation of the Scharlau Invariant, I

    Full text link
    The Scharlau invariant determines whether or not a finite group has a fixed point free representation over a field:\ \ if 00, yes, otherwise, no. Until now it was known to be one of 00, 11, pp, p2p^2 for pp a prime dividing the order of the group. We eliminate p2p^2 as a possibility. Work of Scharlau [Sch] reduces the question to the above list with p2p^2 being possible for the groups SL2(Zp)\text{SL}_2({\Bbb Z}_p) for pp a Fermat prime larger than 55. A computation using GAP in the Senior Thesis [Y] of the second author solves the problem for p=17p = 17. With this motivation, we found a short proof of the result not requiring a computer.Comment: 7 page

    Low pressure hyperbaric oxygen therapy and SPECT brain imaging in the treatment of blast-induced chronic traumatic brain injury (post-concussion syndrome) and post traumatic stress disorder: a case report

    Get PDF
    A 25-year-old male military veteran presented with diagnoses of post concussion syndrome and post traumatic stress disorder three years after loss of consciousness from an explosion in combat. The patient underwent single photon emission computed tomography brain blood flow imaging before and after a block of thirty-nine 1.5 atmospheres absolute hyperbaric oxygen treatments. The patient experienced a permanent marked improvement in his post-concussive symptoms, physical exam findings, and brain blood flow. In addition, he experienced a complete resolution of post-traumatic stress disorder symptoms. After treatment he became and has remained employed for eight consecutive months. This case suggests a novel treatment for the combined diagnoses of blast-induced post-concussion syndrome and post-traumatic stress disorder

    Evaluation of Pavement Markings on Low-Volume Rural Roadways in Iowa

    Get PDF
    Many rural roadways in Iowa have centerline and/or edgeline pavement markings. The current Manual on Uniform Traffic Control Devices (MUTCD), however, requires centerline and/or edgeline pavement markings only along streets and roadways with traffic volumes much greater than 400 vehicles per day (the volume-based definition of a low-volume roadway in the MUTCD). This project was initiated to gather and summarize information about the state of practice related to the installation and maintenance of pavement markings along low-volume rural roadways in Iowa. Additional information was also collected to provide more guidance in the pavement-marking decision-making process. The tasks completed include an examination and summary of past research, the collection of legal input related to the use of pavement markings in Iowa, and a survey of Iowa county engineers that focused on their current pavement-marking practices. A basic safety benefit-cost evaluation of pavementmarking applications was also performed. Overall, the literature on the effectiveness of pavement markings and their safety impacts is limited. A number of studies have been completed with varying levels of robustness and reliability in their results. The Highway Safety Manual includes crash modification factors for the installation of centerline markings that it indicates should be used with caution, and one for the installation of edgeline and centerline markings that equates to a 24 percent total serious and minor-injury crash reduction. A more recent study from Louisiana also found a 15 percent reduction in total crashes after the addition of edgelines. The legal input acquired as part of this project was generally common knowledge. It indicated that once a traffic control device has been installed, the jurisdiction must properly and adequately maintain it. The survey completed found that, of the great majority of the respondents (97 percent), painted centerline/no passing zones and edgelines on at least some of their paved low-volume rural roadways. A much smaller percentage took this approach, or just painted centerlines/no passing zones, along their seal-coated roadways. The basic cost-benefit evaluation found that the percentage of crash reduction needed from pavement markings to make them beneficial was very low (i.e., 5.1 percent, at most). Overall, it was concluded that pavement markings are widely used in Iowa along low-volume paved roadways and sometimes seal-coated roadways. In addition, there is a safety benefit to the installation of pavement markings. but the research into that impact is limited, particularly along low-volume roadways. It is recommended that further analysis be completed on potential pavement-marking safety impacts, that a pavement-marking database be developed, and that a committee be initiated to help develop policies related to pavement-marking removal

    Hybrid Computer Simulation of the Accumulation and Melt Processes in a Snowpack

    Get PDF
    This study represents the first phase of an investigation to develop an operational simulation model of the point snowmelt process based on a time increment of one day or less. Mathematical relationships for various phenomena involved in the snowmelt process were proposed and tested. These relationships were combined into a model which is applicable to any geographic locations by determining appropriate constants for certain relationships. The model was synthesized on a hybrid computer and calibrated using field data from the Central Sierra Snow Laboratory. It was then tested with data from other well instrumented locations. Sensitivity tests were also conducted to study the relative effects of the various basic parameters and functions upon the melting process. Initial tests of the model proved encouraging and suggested merit in perusing a proposed subsequent phase of the project to incorporate the watershed runoff hydrographs resulting from a melting snowpack will be simulated
    • …
    corecore