5,102 research outputs found

    The use of plant functional types as a method of determining plant biodiversity and keystoneness in a northern New Zealand isocline : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Plant Science at Massey University, New Zealand

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    New Zealand vegetation, like the rest of the world, is undergoing increased perturbations due to global climate change. Whether anthropocentric in origin or part of a natural climatic cycle, increased CO₂, increased temperature plus changing regimes of precipitation have been recorded. Environmental change, especially at local levels, does affect community structure. New Zealand's ancient endemic trees and shrubs face the greatest threat of extinction, mainly due to habitat destruction by man for development and by introduced pests. The consequence could be that these trees and shrubs would not be able to migrate naturally in the time frame that climatic change will allow. The use of Plant Functional Types in climate change research is extensive and these groupings are being used more frequently in the study of diversity response to environmental change. The objectives of the Maunganui Bluff study were to develop a methodology to construct PFTs and to utilise these functional groupings in an analysis of the isocline. These analyses were; a diversity study based on richness and abundance, a site ordination and a group analysis. A total of forty-eight PFTs were constructed, then reduced to seventeen. The final seventeen functional groups were used in the following analyses. 1. A diversity analysis. While not appearing useful in comparing species evenness to PFT evenness over the isocline, the analysis did confirm that at that point in space and time when sampling was undertaken, PFTs did conform to the assembly rule for groups. This rule states that there should be equal representation of functional groups at each site from the total available pool 2. Ordination. The second analysis was to determine the effect of the local environment on the spatial position of the PFTs on the isocline. Detrended Correlation Analysis (DCA), an ordination technique, was used to map the groups and the sites against environmental gradients. The results signified that a small number of groups were strongly influenced by potassium (K) but the majority of groups occupied specific sites, on an altitude – phosphorus and nitrogen gradient, due to competition for resources. This summation is supported by altitude being linked to precipitation and leaching, since most of the other environmental data, measured and analysed, were correlated to altitude. 3. Group analysis using Indicator Species Analysis in the computer programme PCORD. The statistical analysis highlighted three PFTs with high keystone rankings p*>.800), one of which was missed by a subjective analysis of the site map of PFTs distribution. When these three groups were deconstructed back to species, the membership of each group was only one species. Of these three species, only Haloragis erecta appeared to be out of place within the gradient. Four hundred metres in altitude is well beyond the plants recognised limit of approximately 120 metres. Since sea level to one hundred and fifty metres is the shrubland zone and site K is also, by species sampled, designated a shrubland, there is evidence that some environmental factor may be associated with these sites. Obviously, this cannot be tested, as there were no Haloragis erecta in the sampled sites from sea level to one hundred and fifty metres. The analysis suffered from a lack of replication for the site under study, as well as comparative sites, to determine the validity of the methodologies. The results while encouraging only reflect a point in both space and time. The work would have needed a much larger range of environmental data, over a longer time frame to ensure that the results were not chance, and would be sustained under more detailed statistical rigor. Many of the premises that the work was based on are subjective. However, despite the lack of statistical rigor, the study confirms the work being carried out using PFTs in other countries. New Zealand's endemic plants do have assembly rules and PFTs constructed with New Zealand natives are valid assemblages that can be used in statistical analysis, and may well turn out to be important in monitoring environmental change

    Water Quality in Pleasant Valley, Utah

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    Pollution of shallow groundwater due to wastewater disposal in Pleasant Valley, Utah, was investigated from October 1979 through August 1980. Water samples were collected from 23 wells and 5 stream sampling sites. Water quality analysis revealed pollution at several sites. Groundwater pollution caused by man’s activities in the area was observed in Bolotas and Scofield Campsite subdivisions. Severe shallow groundwater pollution measured in wells which were located in south and north profiles of the town of Scofield, Utah, could have originated from the municipal waste disposal practice in the town. Natural phenomena, however, such as pyrite oxidation, could possible have been the cause of the depletion of dissolved oxygen in the groundwater near Scofield. In the town of Scofield the shallow water table, less than 1.22 m (4 ft) below ground throughout the whole study period, could limit septic tank use in the study area. The seasonally variable nitrate and phosphate concentration in the surface stream reached its maximum value in May (i.e. 1.12 mg/1 NO3-N and 3.37 mg/1 total phosphorus) when the stream flow reached a maximum flow of 9.06 m3/s (370 cfs). These increases in nitrate and phosphorus content in the stream, sresulting from spring thawing, could increase the nutrient level in the Scofield Reservoir. Natural phenomena produced a high concentration of mercury, averaging 2.55 ug/1 during the study period. It is possible that the water in Scofield Reservoir might have a similar level of mercury. The maximum contamination level of mercury accepted by the State of Utah and U.S. EPA for drinking water is 2.0 ug/1. Therefore, potential health problems may exist for the people who depend on the Scofield Reservoir for their source of drinking water. Fluoride concentration ranged from 0.06 mg/1 to 0.42 mg/1 natural processes are responsible for fluoride in the water

    The Precipitation Characteristics of ISCCP Tropical Weather States

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    We examine the daytime precipitation characteristics of the International Satellite Cloud Climatology Project (ISCCP) weather states in the extended tropics (35 deg S to 35 deg N) for a 10-year period. Our main precipitation data set is the TRMM Multisatellite Precipitation Analysis 3B42 data set, but Global Precipitation Climatology Project daily data are also used for comparison. We find that the most convective weather state (WS1), despite an occurrence frequency below 10%, is the most dominant state with regard to surface precipitation, producing both the largest mean precipitation rates when present and the largest percent contribution to the total precipitation of the tropical zone of our study; yet, even this weather state appears to not precipitate about half the time. WS1 exhibits a modest annual cycle of domain-average precipitation rate, but notable seasonal shifts in its geographic distribution. The precipitation rates of the other weather states tend to be stronger when occurring before or after WS1. The relative contribution of the various weather states to total precipitation is different between ocean and land, with WS1 producing more intense precipitation on average over ocean than land. The results of this study, in addition to advancing our understanding of the current state of tropical precipitation, can serve as a higher order diagnostic test on whether it is distributed realistically among different weather states in atmospheric models

    Warp Breaks Detection in Jacquard Weaving Using MEMS: Effect of Weave on Break Signals

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    This paper reports a study to detect warp breaks in terms of weave structure using MEMS accelerometer based detection system. The system is briefly described. The output signals of MEMS sensors, which were mounted on harness cords of a Jacquard machine, at the moment of warp yarn break and after the break for a broad range of basic weaves were acquired during weaving. The weaves investigated are commonly used in Jacquard weaving to form patterns. The strength of the MEMS output acceleration signals was analyzed in time domain. The results show that the system is capable of detecting warp yarn breaks for the broad range of weaves studied

    Handling qualities of a wide-body transport airplane utilizing Pitch Active Control Systems (PACS) for relaxed static stability application

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    Piloted simulation studies have been conducted to evaluate the effectiveness of two pitch active control systems (PACS) on the flying qualities of a wide-body transport airplane when operating at negative static margins. These two pitch active control systems consisted of a simple 'near-term' PACS and a more complex 'advanced' PACS. Eight different flight conditions, representing the entire flight envelope, were evaluated with emphasis on the cruise flight conditions. These studies were made utilizing the Langley Visual/Motion Simulator (VMS) which has six degrees of freedom. The simulation tests indicated that (1) the flying qualities of the baseline aircraft (PACS off) for the cruise and other high-speed flight conditions were unacceptable at center-of-gravity positions aft of the neutral static stability point; (2) within the linear static stability flight envelope, the near-term PACS provided acceptable flying qualities for static stabilty margins to -3 percent; and (3) with the advanced PACS operative, the flying qualities were demonstrated to be good (satisfactory to very acceptable) for static stabilty margins to -20 percent

    Nuclear safety policy working group recommendations on nuclear propulsion safety for the space exploration initiative

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    An interagency Nuclear Safety Working Group (NSPWG) was chartered to recommend nuclear safety policy, requirements, and guidelines for the Space Exploration Initiative (SEI) nuclear propulsion program. These recommendations, which are contained in this report, should facilitate the implementation of mission planning and conceptual design studies. The NSPWG has recommended a top-level policy to provide the guiding principles for the development and implementation of the SEI nuclear propulsion safety program. In addition, the NSPWG has reviewed safety issues for nuclear propulsion and recommended top-level safety requirements and guidelines to address these issues. These recommendations should be useful for the development of the program's top-level requirements for safety functions (referred to as Safety Functional Requirements). The safety requirements and guidelines address the following topics: reactor start-up, inadvertent criticality, radiological release and exposure, disposal, entry, safeguards, risk/reliability, operational safety, ground testing, and other considerations

    Protocol for a feasibility randomised controlled trial of Screening and Enhanced Risk management for Vascular Event-related Decline in Memory (SERVED Memory)

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    INTRODUCTION: Stroke is a leading cause of death and disability. The development of dementia after stroke is common. Vascular risk factors (VRF) which contribute to stroke risk can also contribute to cognitive decline, especially in vascular dementia (VaD). There is no established treatment for VaD, therefore strategies for prevention could have major health resource implications. This study was designed to assess whether patients with early cognitive decline after stroke/transient ischaemic attack (TIA) can be easily identified and whether target-driven VRF management can prevent progression to dementia.  OBJECTIVES: The primary objective is to establish the feasibility of recruitment and retention of patients with early cognitive decline to a randomised controlled trial of enhanced VRF management. Secondary objectives include: (a) to determine the potential clinical benefit of the intervention; (b) to estimate the sample size for a future definitive multicentre randomised controlled trial; (c) to inform a future economic evaluation; (d) to explore the link between VRF control and the incidence of cognitive impairment on longitudinal follow-up in a UK population after stroke/TIA with current routine management.  METHODS: 100 patients with cognitive decline poststroke/TIA will be recruited from stroke services at the Norfolk and Norwich University Hospital. After collection of baseline data, they will be randomised to intervention (3 monthly follow-up with enhanced management) or control (treatment as usual by the general practitioner). At 12 months outcomes (repeat cognitive testing, VRF assessment) will be assessed. A further 100 patients without cognitive decline will be recruited to a parallel observational group from the same site. At 12 months they will have repeat cognitive testing.  ETHICS AND DISSEMINATION: Ethical approval has been granted in England. Dissemination is planned via publication in peer-reviewed medical journals and presentation at relevant conferences.  TRIAL REGISTRATION NUMBER: 42688361; Pre-results
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