1,525 research outputs found

    Ecology and conservation of Alseuosmia quercifolia (Alseuosmiaceae) in the Waikato region, New Zealand

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    The ecology of Alseuosmia quercifolia, a small endemic shrub, was investigated, focussing on its habitat requirements, population dynamics, phenology and reproductive biology, and conservation status. This species occurs most commonly in lowland native forests of the Waikato region of the North Island (north of latitude 38°05'S), but is also found in scattered populations to North Cape. In the Waikato region it typically occupies shady, well-drained, south or south-east facing lower slopes of hills and ranges at altitudes below 400 m. Population structures show considerable variation amongst seven study sites in the Waikato region, with disjunct size classes a reflection of the presence and abundance of introduced browsing mammals. It is a relatively short-lived (less than 50 years), slow-growing species with a fleshy fruit adapted to bird dispersal, but seed dispersal now appears to be primarily by gravity. Flowering occurs early in spring and is synchronous at both individual and population levels, occurring over a 5-week period, with peak flowering during the second and third weeks. While all populations set seed, reproductive output can be negatively affected by persistent browse and by rain during peak flowering. This species is vulnerable because it is highly palatable to introduced mammals and all plants in a population are within browse height. It has relatively narrow habitat specificity, localised distribution, and limited potential to extend its range. We suggest it fulfils the requirements of the category "declining", using the most recent classification of threatened and uncommon plants of New Zealand

    The Development of Chemical and Biological Profiling for the Forensic Provenancing of Norfolk Soils

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    Soils are frequently analysed by forensic laboratories by comparing a suspect sample to an especially collected control sample. As yet, they cannot be compared to a central database, unless the area in question has already been identified; with the use databases being highly contested within the field of forensic geosciences. There is a need for a method of soil profiling that allows an unknown sample to be tested and assigned a quantitative likelihood that it originated from a given region. Spatial models can then be created using geographical information systems to house multiple datasets and be used to map soils across geographical areas. Generally, the more variables available with which to compare items, the greater the certainty a forensic analyst can have when asserting their similarity; this applies to geological materials. Equally, soil profiling methods can be used to exclude soil samples from each other or an area. This research involves a number of chemical and biological profiling methods that have been used to build up a unique signature for soils from different locations across Norfolk. All analyses have been carried out on a single source sample. 87Sr/86Sr ratios have been measured using MC-ICP-MS, and trace element concentrations measured using ICP-MS. The 87Sr/86Sr ratios are significantly different at each of the sample locations; although there is some variation in the replicates collected at each location this variation is smaller than the regional variation. The correlation between the isotope chemistry of the topsoil and the underlying geology is poor, indicating that other sources such as land-use, vegetation cover and additions to the soil contribute to the 87Sr/86Sr. Therefore, trace element concentrations have been used to spatially discriminate samples and to investigate the effect of fertilisers on the elemental composition of the topsoil. The biological techniques used to aid discrimination are soil DNA analysis using the chloroplast-located matK gene and MALDI-ToF-MS, palynology and the creation of Norfolk vegetation maps showing all of the plant species recorded in the area; each additional independent dataset allows for an increasing signature of each sample to be built up which can be used for assessing similarity or exclusionary purposes

    The Role of Autobiographies in Activism: How Former 'Comfort Women' Used Testimonies to Fight for Their Rights

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    Imagine you are in a room of women from different cultures and backgrounds. You may be inclined to think that these women have nothing in common. However, if you were to ask them if they had experienced sexual harassment, four of out five (81%) would raise their hands (Chatterjee). According to the National Sexual Violence Resource Center, one in five women have also been raped. Sexual violence defines the female experience. Female sexuality has always been centered around and dictated by men, their desires, and their sexual urges. Rebecca Solnit says, “sex is an arena of power” (108) and has long been a way to shame, control, and own women. Men have defined when, with whom, and under what circumstances women are allowed to have sex, and through an emphasis on female virginity, have controlled and regulated women and their bodies (Jung, Soh, and Solnit). Sex is one of the most basic components of human existence, and to exert control over someone’s sexuality is to take away their most basic freedom and their sense of security

    An economic model for evaluating strategies on the south coast of W.A. which reduce wind erosion : documentation

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    The sandplain region on the south coast has predominately sandy soils which are subject to erosive winds when ground cover is likely to be scarce. This can often result in production losses of crop and pasture. There is concern that wind erosion will lead to the depletion of the soil resource in the long term. The model is multi-period linear programming with a planning horizon of 10 years. Effects of wind erosion on production can be imposed on the model for the first five years after the erosion event

    The effect on farm profit of conserving stubble to prevent wind erosion

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    Over-grazing of stubbles is a major cause of winf erosion on WesternAustralian farms. Stubble contributes to the \u27roughness\u27 of the paddock; as the roughness is reduced, the risk of winf erosion is increased. The risk of lupinosis in sheep has previously reduced the likelihood of lupin stubble being over grazed, but the development of Gungurru, a phomopsis-resistent variety of lupin, has increased the potential for over-grazing and hence the probability of wind erosion. This article describes the economic benefit (or cost) of conserving stubble at the conservation standards

    The use of magnetic fields to create high-speed plasma jets for spacecraft propulsion

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    The aim of the work reported in this thesis has been to explore arrangements of magnetic fields and electric currents to create novel plasma thrusters that are more efficient and less complex than existing designs. Two original devices are discussed, firstly a thruster that uses a magnetic nozzle in combination with a High Power Impulse Magnetron Sputtering source (HiPIMS) to produce a jet of copper plasma and secondly, a thruster that uses the phenomena of magnetic reconnection that occurs between opposing magnetic fields in a plasma to produce a plasma jet. While HiPIMS has been normally employed to create thin films, the use of a solenoidal magnetic field to accelerate and focus the ions produced by that source has not been previously investigated as a means of creating a thruster. The HiPIMS thruster has a specific impulse (Isp) of 1543s. Magnetic reconnection has been studied for decades by geophysicists and by astronomers. Despite that effort, so far there has been little interest in exploiting the phenomena as a means of producing high-speed plasmas in a thruster despite the evidence of jets in those environments. A thruster consisting of two slit coaxial tubes of copper was constructed. Evidence for the occurrence of magnetic connection was fourfold. (1) A significant electron current that coincided with the rise of the magnetic field that was followed by a large ion current. (2) Ion currents were found to increase as the plasma became less collisional. (3) Ions with energies greater than 130 eV corresponding to a speed of 2.50 x 104 m/s and an Isp of 2550s were detected. (4) The ratio between the estimated speed of ions flowing into the diffusion layer (350m/s) and the measured speed of the out-flowing ions (2.50 x 104 m/s) was approximately 68. The physics indicates that such a thruster could have a basic energy efficiency of 50%

    Studies on the cryopreservation of boar spermatozoa and its integration into assisted reproductive technologies

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    The aim of this thesis was to investigate the possibility of integrating frozen-thawed boar semen into reproductive technologies and into commercial production of pigs in Australia. This was to be achieved by establishing a semen freezing and AI regime that was of a standard acceptable to industry, and integrating the resultant frozen-thawed sperm into other reproductive technologies, such as flow cytometric sperm sorting and IVF. Initially, a protocol for freezing and thawing boar semen was established, based on the method described by Westendorf et al. (1975) and attempts were made to modify this protocol to improve the post-thaw sperm quality, as determined by in vitro assessment of motility, acrosome integrity and longevity. First, the egg yolk used in the freezing extenders was investigated, and the chicken yolk was replaced with either duck or quail yolk. It was shown that there was no benefit in substituting yolk from duck or quail for the chicken yolk traditionally used in freezing extender. Second, the effect of seminal plasma addition to the freezing extender, or seminal plasma addition to resuspension medium post-thaw was tested. Incorporating whole seminal plasma into the freezing extender at levels above 50% was found to be detrimental to post-thaw sperm quality. Reducing levels to 20% of the final volume improved acrosome integrity, but adversely affected motility of sperm. However, adding 20% seminal plasma to the resuspension medium used after thawing of boar semen had no significant influence on sperm quality compared with resuspension in medium without seminal plasma. The antioxidant catalase, and the iron chelator desferal added to the freezing extender, did not improve post-thaw sperm quality, nor was any benefit seen with addition of these substrates to the resuspension medium post-thaw. However, the bioactive phospholipid PAF and its regulating enzyme PAF:AH appeared to enhance post-thaw motility and acrosome integrity of sperm, respectively, when added to the semen pre-freezing. Unfortunately, due to the restrictions imposed on rPAF:AH as a research drug, it was not possible to test the in vivo effects at this time. After the in vitro experiments were completed, the in vivo fertility of frozen-thawed sperm was tested using the optimal freezing protocol and a novel technology, enabling non-surgical deep intrauterine insemination of sows. The aim was to establish the lowest possible dose of frozen-thawed sperm that could be used, without compromising fertility. Successful pregnancies were achieved with doses as low as 62.5 x 106 frozen-thawed sperm but the farrowing rates were too low to be practicable on a commercial scale. This is the first report of litters born after insemination of such a low dose of frozen-thawed sperm and using the novel DIU insemination technique. However, it was concluded that a double dose of 250 x 106 frozen-thawed sperm was the minimum dose required for maintaining acceptable fertility. Reduction in sperm numbers to such an extent made it possible to consider non-surgical insemination of sex-sorted, frozen-thawed semen. Previously, pregnancies had been achieved only after surgical insemination of sex-sorted boar sperm, or with DIU insemination of unfrozen sperm, immediately after sex-sorting. The low numbers of sex-sorted sperm available restricted the inseminate dose used here to 50 x106 motile sperm. A litter of 5 piglets was born after a low-dose, DIU insemination of sex-sorted, frozen-thawed sperm. This is the first report of piglets born after insemination with sex-sorted frozen-thawed sperm and non-surgical insemination. The low farrowing rate achieved in this experiment prompted the investigation of integrating sex-sorted, frozen-thawed boar sperm into IVF. Morulae were produced after IVF with sex-sorted, frozen-thawed sperm and successfully transferred using non-surgical techniques. This is the first report of pregnancy achieved with non-surgical transfer of embryos produced after IVF and IVC of IVM oocytes with sex-sorted, frozen-thawed boar sperm. Unfortunately, the pregnancy did not hold, and the embryos were lost prior to Day 32, but PCR of non-transferred embryos confirmed successful pre-selection of sex. Overall, this thesis demonstrated that it is still not economically feasible to incorporate frozen-thawed boar semen into the commercial production of pigs although it has considerable application in breeding programmes. However, the development of novel techniques enabling reduction in sperm dose, and for non-surgical transfer of embryos into recipient sows and incorporation of frozen-thawed semen into these technologies means that progress is being made with the integration of reproductive technologies and frozen-thawed semen into the pig industry

    Derivation of supply curves for catchment water effluents meeting specific salinity concentration targets in 2050: linking farm and catchment level models or “Footprints on future salt / water planes”

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    The salt burden in a stream reflects the blend of salty and fresh flows from different soil areas in its catchment. Depending not only on long-run rainfall, water yields from a soil are also determined by land cover: lowest if the area is forested and greatest if cleared. Water yields under agro-forestry, lucerne pasture, perennial grass pasture, and annual pasture or cropping options span the range of water yields between the extremes of forested and cleared lands. This study explores quantitative approaches for connecting the hydrologic and economic consequences of farm-level decisions on land cover (productive land uses) to the costs of attaining different catchment level targets of water volumes and salt reaching downstream users; environmental, agricultural, domestic, commercial and industrial. This connection is critical for the resolution of the externality dilemma of meeting downstream demands for water volume and quality. New technology, new products and new markets will expand options for salinity abatement measures in the dryland farming areas of watershed catchments. The development of appropriate policy solutions to address demands for water volumes and quality depends on the possibility of inducing targeted land use change in those catchments or parts of catchments where decreased saline flows or increased fresh water flows can return the best value for money. This study provides such a link.salinity, targets, opportunity cost, concentration, dilution, effluent, externality, supply, demand, policy, water quality, new technology, new markets, Resource /Energy Economics and Policy,

    Coal dust: a clinical and radiological review of its effects on the health of coal trimmers

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    "The importance of Dust as a factor in Occupational Mortality has attracted the attention of every living authority on occupational diseases from Ramazzini to Sir Thomas Oliver." This statement from a book "Occupational Diseases ", by an American author 3) - Goldberg, affords a fitting apology for a study of one of the less well known forms of dust hazard.The work entailed in writing this Thesis has been carried out by the author while engaged in General Practice. In all branches of Medical work one is brought into close contact with the lives of one's patients, but this is perhaps particularly true in the case of the General Practitioner, and to be of real service to his patients, he must understand something of the work they do and the conditions under which this work is carried out. Above all, he must attempt to give relief to the ailments his patients exhibit, and is often expected to afford this solace.in cases where advanced pathological changes render it impossible to do so. The medical problems arising out of Industry naturally vary with the particular occupation involved, and such problems will be of greater or lesser interest to the Medical Profession in general, according to the widespread or restricted nature of the Occupation, but individual Practitioners, working in an area with one or more basic industry, must thoroughly understand the special effects such occupation or occupations have on the health of their patients employed in the particular industry.Before this work was commenced, the author was impressed by the large number of men in his own area in South Wales giving their occupation as Coal Trimmers, who presented severe symptoms principally related to the respiratory tract, and to whom relief was afforded with difficulty. This prompted a desire to learn more of the mode of onset and the progress of the disability from which these men suffered, and it was felt that this desire could be gratified by a clinical and radiological review of a series of cases.A wide interest has been taken in the effects of dust on the Coal Miner. This is due in part to the striking nature of his work and in part to the large number of men involved all over the country. In any study of dust hazards, the miner usually comprises one of the occupational groups considered, and particular attention has been paid to the miner in South Wales in numerous papers by various workers.The Coal Trimmer has not received such wide attention. This occupation is briefly referred to in several papers and has been the subject of at least one Official Survey by the Medical Research 3. Council(11),but in view of the fairly widespread nature of the occupation, and the obvious exposure to large quantities of coal dust, it is felt that a special survey of this particular dust hazard cannot be without interest and importance.It is necessary to emphasise at the outset that the hazards attached to the occupation of Coal Trimming are to a very large extent different from those experienced by men engaged in handling coal at other stages of its production and transit. Were this not so, the study now presented would be a mere reiteration of facts already well known from work done on Coal Miners. The differences in the risks to which the Coal Trimmer is exposed, compared to those experienced by the Coal Miner, can best be appreciated by a note on the respedtive conditions of work
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