435 research outputs found

    Modelling the spreading of wilding conifers

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    In many parts of the Canterbury high country, conifer seeds are spreading on the wind from exisiting plantations and shelterbelts, leading to a serious weed problem. Environment Canterbury set the task at MISG to model this spread, and thus provide a basis for prioritising control operations on a limited budget. The study group provided increased understanding of topographic and climatic factors involved in seed dispersal, and of the distribution of the resulting seed rain. In addition a simulation framework was developed for comparing the effectiveness of different control strategies

    Factors associated with trends in bare ground in high country

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    Environment Canterbury has responsibility for promoting sustainable management of the region’s natural resources. Soil erosion in the Canterbury high country has been a long-term concern, and was the subject of the problem brought to MISG. Pre-European and early European burning and grazing not only induced large tracts of tussock grassland in areas that were previously wooded, but also exposed areas of soil to further erosion by wind, rain and frost. In the 1960s to 1980s the government encouraged de-stocking on some properties, with the aim of restoring vegetative cover. In the late 1970s, a monitoring programme was set up in parts of the Canterbury high country to track the effects of lowered grazing levels

    Nine Companions: Exploring Loyalty Beyond Logic in J.R.R. Tolkien's The Fellowship of the Ring

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    J.R.R. Tolkien fought in the trenches in one of the most horrific battles of WWI: the Battle of the Somme. He lost many close friends in the in the war, which may have affected the way he viewed concepts like loyalty. In addition, scholars agree that Beowulf- an epic in which loyalty is a key theme- influenced Tolkien as well. His focus on loyalty is very different from his more pessimistic modernist contemporaries because he chooses to focus on the ability of good to overcome evil in the end through friendship and loyalty. This thesis examines these dynamics in The Fellowship of the Ring. Some critics claim that Tolkien’s views are simplistic; but Tolkien knows, better than most, what darkness and despair look like and chooses to take a more positive outlook and focus on themes like strength, courage, and friendshi

    Synthesis of compounds capable of producing cytotoxic N3-methyladenine DNA adducts in estrogen receptor positive cells

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    This project describes the design and synthesis of new compounds that are capable of targeting cells that express the estrogen receptor and producing cytotoxic N3-methyladenine DNA adducts in those cells. These compounds contain a reactive methylsulfonate group connected to a unit that binds to DNA in the minor groove at adenine-thymine rich regions, and therefore, selectively methylates adenines in these regions at the N3 position. This component is connected by a linking unit to estradiol, which binds to the estrogen receptor, and therefore, is expected to selectively target these compounds to cells that express the estrogen receptor. The linking unit is the only variable component in the design, and can be altered in order to optimize the DNA and estrogen receptor binding properties of the compound, and to modulate the water solubility of the compounds. The synthesis of three compounds varying in linker length by one, two, and three methylene units is described

    Putting induction into practice: a case study of how school context mediates induction policies and practices

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    This study describes beginning teacher support and retention in four high schools in a large school district in North Carolina. State and district policies mandate that all beginning teachers receive multiple layers of mentor support, including district mentors, school-level mentors, school buddies, and school Induction Coordinators. Little is known about how individual schools enact the induction policies set forth by the district, or about individual teacher’s response to the activities within a given school context. This qualitative research study on the nature of the implementation of induction at four different high school sites and beginning teachers’ experiences in these contexts during their first two years provided information about the kinds of support that beginning teachers need and receive, and the impact that induction practices had on their decisions to stay, move to another school, or leave the profession. Data collection from 25 first and second year teachers and 13 Support Providers (district administrators, school administrators, mentors, and Induction Coordinators) provided evidence regarding what factors were helpful to them for transitioning into their professional roles and what factors most influenced their decisions to stay or leave. The general research question for this study is: “How do participants (Support Providers and beginning teachers) involved with induction perceive the relationship between school context, support, and teacher retention at their respective schools?” Two specific research and several sub-questions guided this study: 1) How do participants perceive support for beginning teachers at their schools? *How do they perceive the implementation of induction policies and practices at their schools? *How do participants perceive other types of support at their schools? 2) Why do some beginning teachers choose to leave, and why do some beginning teachers choose to stay in their schools? *How do participants perceive support needs in relationship to the unique needs of their school? *How do participants perceive retention for beginning teachers at their schools? The research found that Support Providers and Beginning Teachers cited similar sources of support for beginning teachers, including induction-related activities, mentors, administrators, and colleagues. Some teachers found induction supports cumbersome, time consuming, and misaligned to their needs. Support Providers reported that a primary role in support of beginning teachers was to provide a menu of options for beginning teachers to choose from. District personnel felt that they set up a strong structure of support for beginning teachers, but that they felt constrained by their case-load to work with schools with large numbers of beginning teachers. All participants felt that beginning teachers who left their school were not adequately prepared for and supported in their particular school environment. Beginning teachers who stayed did so because of their passion for working with their students and satisfaction from seeing students make academic gains, regardless of whether or not they felt supported by their administration. These teachers had a personal commitment to their school and students and felt supported enough to continue in their respective schools. Each of the four schools presented a unique teaching context. As a result, the needs of the beginning teachers varied greatly depending on the school’s needs and their individual preparation and expectations for the role. Induction was embedded in each school’s particular culture, and as a result, district level induction policies played out differently at each school

    Landscape aspects of oyster reefs : fragmentation and habitat utilization

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    The functional value of oyster reefs is recognized in many estuarine systems, with increasing interest in oyster reef restoration for ecological function rather than for fishery production. Reefs provide structure and refuge for juvenile fish and crustaceans, and may be a locus for predator foraging. However, reef morphology influences the relative value of refuge and forage functions, and reef utilization by benthic, epibenthic, and nektonic organisms. Reef fragmentation will increase the edge to interior ratio, and may enhance use by organisms that favor edge regions, or decrease use by species requiring more interior habitat. The influence of fragmentation was examined using created intertidal oyster reefs and natural reef patches in southeastern North Carolina. Created reef treatments included a uniform circular reef, a small fragmented reef, a large fragmented reef, and reference natural reef and mudflat areas. In addition, uniform and fragmented patch reefs in two nearby tidal creeks were also sampled. All treatments were sampled immediately after construction in June 2002, and then quarterly over two years, targeting infauna, epifauna, and nekton. Effects of fragmentation on infuana were variable, with a combination of positive and negative species-specific responses. However, preferential use of large fragmented reefs over small fragmented reefs was observed for Lagodon rhomboides, Panopeus herbstii, and Geukensia demissa, suggesting that the small fragmented reefs were most likely below the patch size threshold at which edge effects become beneficial. Implications are that oyster reef fragmentation may be an important factor for restoration managers to consider when designing reefs in which increased habitat utilization is a primary goal. Although a degree of fragmentation may be beneficial for some species, once fragmentation leads to a loss of reef area below critical thresholds, degradation effects on habitat utilization could be great

    Evidence for ACTN3 as a genetic modifier of Duchenne muscular dystrophy

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    Duchenne muscular dystrophy (DMD) is characterized by muscle degeneration and progressive weakness. There is considerable inter-patient variability in disease onset and progression, which can confound the results of clinical trials. Here we show that a common null polymorphism (R577X) in ACTN3 results in significantly reduced muscle strength and a longer 10\u2009m walk test time in young, ambulant patients with DMD; both of which are primary outcome measures in clinical trials. We have developed a double knockout mouse model, which also shows reduced muscle strength, but is protected from stretch-induced eccentric damage with age. This suggests that \u3b1-actinin-3 deficiency reduces muscle performance at baseline, but ameliorates the progression of dystrophic pathology. Mechanistically, we show that \u3b1-actinin-3 deficiency triggers an increase in oxidative muscle metabolism through activation of calcineurin, which likely confers the protective effect. Our studies suggest that ACTN3 R577X genotype is a modifier of clinical phenotype in DMD patients

    Enzymatic response of Callinectes sapidus and Geukensia demissa as biomarkers for pesticide exposure

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    The widespread commercial and private use of organophosphate (OP) and carbamate pesticides, and their subsequent presence in aquatic ecosystems, is cause for concern in terms of both environmental and human health. Disruption of acetylcholinesterase (AChE) activity is a primary mode of acute toxicity of OP pesticides to non-target organisms, and this inhibition has been used in limited settings as a biomarker of OP/carbamate exposure. A second hydrolyzing enzyme, carboxylesterase (CBE), is also inhibited upon exposure to these compounds; used in conjunction with AChE activity, it may provide a more inclusive biomarker than AChE activity alone. In this study, two aquatic invertebrates were studied as potential indicator species of pesticide pollution. Enzymes were characterized for Michaelis-Menten kinetics, and in vitro and in vivo tests were conducted to assess the impact of OP and carbamate compounds on each enzyme, in both hemolymph and tissue in both species. In general, the blue crab, Callinectes sapidus, showed higher mortality at lower concentrations than did the ribbed mussel, Geukensia demissa. However, G. demissa showed more significant enzyme inhibition at sub-lethal concentrations, making it a more effective indicator of a potential threat. Although enzyme inhibition rarely occurred at environmentally relevant concentrations of a single contaminant, the more probable presence of multiple or chronic stressors could effect a measurable response in situ

    Posttraumatic stress disorder symptoms and the substance use following September 11th

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    The terrible events that unfolded on September 11, 2001 affected the entire world, especially people in the United States. This study assessed symptoms and correlates of posttraumatic stress disorder (PTSD) and examined substance use following the attack. There were 210 participants from the NY, NJ, and Conn. areas surveyed on the beach 8- 10 months after 9/11. Participants were asked about their retrospective accounts and their current reports of symptoms and substance use. Results showed that people who were within a one-mile radius of the World Trade Center (WTC) on 9/11 had more frequent PTSD symptoms retrospectively and 8-10 months following the attack than people who were 45-60 miles away. There was a significant correlation between retrospective accounts of PTSD symptoms and substance use six months following 9/11. There was also a significant correlation between PTSD symptoms 8-10 months after 9/11 and substance use six months following 9/11. A t-test revealed that substance use in the six months after 9/11 was not significantly different from substance use in the six months before 9/11. Even 8-10 months after the terrorist’s attacks of September 11, 2001 participants reported considerable psychological imbalance