7,753 research outputs found

    Healing the Whole Man

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    Casting propellant in rocket engine

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    A method is described for casting a solid propellant in the casing of a rocket engine having a continuous wall with a single opening which is formed by leaves of a material which melt at a temperature of the propellant and with curved edges concentric to the curvature of the spherical casing. The leaves are inserted into the spherical casing through the opening forming a core having a greater width than the width of the single opening and with curved peripheral edges. The cast propellant forms a solid mass and then heated to melt the leaves and provide a central opening with radial projecting flutes

    Resource Mediated Competition of two South Texas Natives: _Acacia berlandieri_ and _Trichloris pluriflora_

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    *Background/Question/Methods* 
_Acacia berlandieri_, an early-successional C~3~ woody shrub legume, and _Trichloris pluriflora_, a late-successional/climax C~4~ mid-tall grass, reside in similar habitats and have both been documented in Texas for over 150 years. This study examines the resource mediated above and below ground competition within and between these species, which may illuminate some of the dynamics involved in the encroachment of woody shrub species into the former grasslands. These species, started from seed, were grown outdoors (5 replicates/treatment) using sandy clay loam soil in plastic lined 15×15 cm pots for 155 days and watered daily. Half of these pots received 12.5% Hoagland’s solution as a nutrient source. Growth measurements were taken 3 times, after a 72 day establishment period and prior to harvest. The plants were then harvested intact, dried at 60°C, and above and below ground dry mass for each individual plant was separated. The roots were ashed at 650°C and measurements were taken for the above and below ground biomass. 

*Results/Conclusions* 
The growth parameters of _Acacia berlandieri_, basal diameter, height, and number of leaves increased with density (P = 0.0024, P < 0.0001, and P < 0.0001), when grown in competition with _Trichloris pluriflora_, using the densities of 1/3, 2/2. 3/1, and 4/0 _Acacia/Trichloris_ plants/pot. None of these growth parameters for _A. berlandieri_ had an effect on the variables of density, nutrients or and their interaction (P > 0.0500), when grown alone with densities of 1, 2, and 4 plants/pot. The growth parameters of _T. pluriflora_, culms and height decreased with density (P = 0.0077 and P = 0.0006), when grown in competition with _A. berlandieri_, using densities of 1/3, 2/2. 3/1, and 4/0 _Trichloris/Acacia_ plants/pot. The culms, tillers, and height of _T. pluriflora_, when grown alone with densities of 1, 2, 4, and 8 plants/pot, decreased with density (P < 0.0001, P = 0.0312, and P < 0.0001). The measurement parameters of harvested _A. berlandieri_, above ground biomass and ash-free root biomass increased with density (P = 0.0463 and P = 0.0389), when grown in competition with _T. pluriflora_. The root biomass of harvested _A. berlandieri_, grown alone, decreased with the interaction of density and nutrients (P = 0.0068). The total plant dry mass, above ground biomass, root dry mass, and root dry mass of harvested _T. pluriflora_, grown in competition with _A. berlandieri_, decreased with density (P < 0.0001, P < 0.0001, P = 0.0235, and P = 0.0145). These same measurement parameters of harvested _T. pluriflora_, grown alone, increased with density (P < 0.0001 for all four). The addition of nutrients had no effect on the growth or harvest of _A. berlandieri_ and _T. pluriflora_ for either intra- or interspecific competition. Instead, density appeared to be the driving force for the competition between and among these two species for both growth and harvest. Although woody shrub and grassland interactions should be mediated by resource availability, that was not the case in this study. Clearly, density is an important variable involved in the disappearance of the grasslands

    Experiments for satellite and material recovery from orbit. Volume I - Summary Final report

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    Experiment missions for OSO satellite rendezvous, capture, material retrieval, refurbishment, and extravehicular operation wor

    Experiments for Satellite and Material Recovery from Orbit. Volume III - Experiment Missions Final Report

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    Experiment missions for OSO satellite rendezvous, capture, material recovery, refurbishment, and extravehicular operation wor

    Influence of sediment redox conditions on uranium mobilisation during saline intrusion

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    This research was funded by the Natural Environment Research Council (grant NE/C506799/1: Studentship NE/H527116/1)

    Child homicide: generating victim and suspect risk profiles

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    Purpose – In England and Wales, on average one child every week is a victim of homicide. The purpose of this paper is to explore whether different victim-risk profiles and suspect variables can be differentiated for specific victim ages. Design/methodology/approach – This paper presents a preliminary analysis of more than 1,000 child homicides committed in England and Wales between 1996 and 2013, from data provided through the Homicide Index. Statistical techniques such as cluster analysis were used to identify specific victim-risk profiles and to analyse suspect variables according to the age of victim. Findings – The findings present a clearer picture of the risk-age relationship in child homicide, whereby several specific risk profiles are identified for specific child ages, comprised of crime variables including; likely victim and suspect demographics, the most likely circumstances of the homicide and methods of killing. Using similar techniques, a number of tentative clusters of suspects implicated in child homicide are also described and analysed, with suggestions of further analysis that might prove of value. Practical implications – The practical implications cannot be understated. For those professionals working in the fields of child protection and criminal investigation the identification of risk profiles promises to provide a back-cloth with which to practice when confronted with complex and distressing child homicide scenarios. This research promises most to those currently training in related professions. Originality/value – Although the statistical level of risk has been linked with the age of a child (with younger children being most vulnerable to killing by a parent or step-parent and older children most vulnerable to killing by acquaintances and strangers), extant research is yet to progress beyond the identification of broad age-risk categories. The paper concludes with a discussion of the likely implications for those charged with reducing and investigating child homicide and outlines the possibility of future research

    Unusual suspects: identifying active serious offenders by self-selection policing

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    The present thesis examines the emergent and complementary investigative method known as self-selection policing. This method seeks to identify minor offences indicative of more serious criminality, whereby the serious offender volunteers him or herself for warranted police attention by dint of committing a minor (often considered innocuous) infraction of the law. In early chapters a conceptual and theoretical underpinning for self-selection is developed by exploring relevant criminological and psychological theory. Terms and concepts are clarified early on, for example, discussion and clarity are provided regarding what constitutes serious and minor offences and offenders. Next, a series of exploratory studies is presented whereby specific minor offences are identified and their utility as indicators (or ‘flags’) for more serious criminality tested. These include non-compliance with Home Office Road Transport Form 1 (HO/RT1), where drivers are required to present necessary motoring documents to police within seven days, and the giving of false details to police. After presenting a theoreical and empirical case for using self-selection policing, late chapters explore anticipated obstacles to its wider implementation. For example, a study is presented which demonstrates a general overestimation of offence homogeneity by police. The implications of this finding for self-selection policing are discussed. The present thesis concludes by suggesting where self-selection policing sits both conceptually and theoretically within academic criminology, and within operational policing. For example, suggestions are offered as to how police and public might be convinced of the utility of self-selection policing and how it might be best integrated with mainstream policing

    Are there errors in glycogen biosynthesis and is laforin a repair enzyme?

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    Glycogen, a branched polymer of glucose, is well known as a cellular reserve of metabolic energy and/or biosynthetic precursors. Besides glucose, however, glycogen contains small amounts of covalent phosphate, present as C2 and C3 phosphomonoesters. Current evidence suggests that the phosphate is introduced by the biosynthetic enzyme glycogen synthase as a rare alternative to its normal catalytic addition of glucose units. The phosphate can be removed by the laforin phosphatase, whose mutation causes a fatal myoclonus epilepsy called Lafora disease. The hypothesis is that glycogen phosphorylation can be considered a catalytic error and laforin a repair enzyme
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