26 research outputs found

    Examining Transylvanian Saxon Fortified Churches from the 13th to the 16th Centuries; the History and Archaeology of the Saxon Rural Church in Romania: Roles and Identities

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    This PhD thesis provides a multi-layered analysis of Saxon rural fortified churches from the thirteenth to the sixteenth centuries in Transylvania. By examining the histories and archaeologies of these poorly studied but prominent medieval survivals, the thesis explores the processes by which the Church transformed Saxon social structures and considers how far structure and form reflect that society and its evolving identities. The timeframe spans the primary Saxon colonization of Transylvania until the occupation of the region by the Turks after 1526. Critically, almost all of the Saxon villages and churches originated and were subsequently fortified during this period and many have remained relativity unaltered since. Three major research strategies are employed: (l) a quantitative analysis of data for the representative regions of Brasov and Sibiu Counties; (2) detailed analysis of the form and function of the built units; and (3) detailed assessment of two major case studies. Data were collected from published and archival reports and sources, plus interviews, newspapers and site surveys. Core to the whole is the creation of a Gazetteer of Saxon sites in BraÅŸov and Sibiu Counties. The thesis considers Saxon fortified complexes in their site and landscape setting, but first reviews medieval to modem Saxon Transylvania, evaluating the impact of events on the Saxon peoples, and then details the nature of Saxon rights, privileges, and administration in their lands and settlements. The roles and development of the Saxon fortified churches are next explored, assessing topographic, defensive, material and economic considerations and evolutions. The final part of the thesis analyses the morphology, domestic, cultural and social life of the Saxon fortified church and village, through which we may assess other angles of evolving Saxon identity. In addition, the thesis has considered the heritage of complexes - how viewed, how maintained, issues of access, of decay - and their recognition by UNESCO and European Union departments. The thesis reveals a specific Saxon colonial form which adapted to a near constancy of threat and uncertainty. The survival of so many components of this distinctive past requires far more attention from scholars to appreciate fully the Saxon contribution

    Role of Surface States in Silver-Doped CdSe and CdSe/CdS Quantum Dots

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    The effects of Ag doping of CdSe and CdSe/CdS quantum dots (QDs) have been studied as a function of the surface composition. Throughout these studies, static and time-resolved luminescence and transient absorption measurements are used to determine the nature and rates of radiationless decay mechanisms and how these vary with the concentration of Ag dopants. In tributylphosphine-ligated CdSe, the photoluminescence quantum yield (PL QY) varies nonmonotonically with dopant concentration, increasing at low concentrations of Ag<sup>+</sup> then decreasing with further addition. The initial increase is assigned to the passivation of preexisting surface hole traps by interaction of interstitial Ag<sup>+</sup> with surface Se<sup>2–</sup> ions, whereas the subsequent decrease is due to the introduction of substitutional Ag<sup>+</sup> dopants, which act as a new source of hole traps. Ligation of the particle surface with alkyl amines largely passivates the surface hole traps and thereby eliminates the initial increase in PL QY upon doping. CdSe/CdS QDs ligated with oleylamine (and no phosphines) exhibit extensive thermal population of empty surface orbitals by valence band electrons. Photoexcitation of these surface-charged particles results in what is essentially a positive trion, which can undergo rapid Auger decay. The presence of oleylamine reduces much of the Ag<sup>+</sup> to Ag<sup>0</sup>, and the addition of Ag<sup>0</sup> dopants passivates these empty surface states and eliminates the surface charging and hence positive trion formation

    Aerial Prefeeding Followed by Ground Based Toxic Baiting for More Efficient and Acceptable Poisoning of Invasive Small Mammalian Pests

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    <div><p>Introduced brushtail possums (<i>Trichosurus vulpecula</i>) and rat species (<i>Rattus</i> spp.) are major vertebrate pests in New Zealand, with impacts on conservation and agriculture being managed largely through poisoning operations. Aerial distribution of baits containing sodium fluoroacetate (1080) has been refined to maximise cost effectiveness and minimise environmental impact, but this method is strongly opposed by some as it is perceived as being indiscriminate. Although ground based control enables precise placement of baits, operations are often more than twice as costly as aerial control, mainly due to the high labour costs. We investigated a new approach to ground based control that combined aerial distribution of non-toxic ‘prefeed’ baits followed by sparse distribution of toxic baits at regular intervals along the GPS tracked prefeeding flight paths. This approach was tested in two field trials in which both 1080 baits and cholecalciferol baits were used in separate areas. Effectiveness of the approach, assessed primarily using ‘chewcards’, was compared with that of scheduled aerial 1080 operations that were conducted in outlying areas of both trials. Contractors carrying out ground based control were able to follow the GPS tracks of aerial prefeeding flight lines very accurately, and with 1080 baits achieved very high levels of kill of possums and rats similar to those achieved by aerial 1080 baiting. Cholecalciferol was less effective in the first trial, but by doubling the amount of cholecalciferol bait used in the second trial, few possums or rats survived. By measuring the time taken to complete ground baiting from GPS tracks, we predicted that the method (using 1080 baits) would be similarly cost effective to aerial 1080 operations for controlling possums and rats, and considerably less expensive than typical current costs of ground based control. The main limitations to the use of the method will be access to, and size of, the operational site, along with topography and vegetation density.</p></div

    Predicted percentage cost-saving in ground-based control by prefeeding aerially rather than ground laying prefeed baits, and assuming 5h of bait laying per day.

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    <p>The blue line indicates savings when toxic baits are laid directly on the ground as in this study, while the red line estimates savings relative to a bait station operation in which an additional visit is necessary to remove baits stations. The dotted lines indicate the mean rate of baiting from the two trials, and the predicted cost-savings by prefeeding aerially. Greater proportional savings are obtained where the rate of ground baiting is slower (e.g. in difficult terrain), and where it is not necessary to deploy baits in bait stations.</p

    Location of the two trial sites in North and South Islands of New Zealand.

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    <p>Location of the two trial sites in North and South Islands of New Zealand.</p

    Predicted person-days required (based on 7h of baiting per day) for contractors to complete control, using the method tested here, in areas of 1000, 5000, and 10 000ha, at different baiting rates.

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    <p>The vertical dotted line indicates the mean rate of baiting from the two trials, and the horizontal dotted lines predict the person-days required to complete the three area sizes.</p

    A ‘chewcard’ attached to a tree close to the ground.

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    <p>Peanut paste bait has been pressed into the hollow ribs of the card attracting interference by common pest species.</p

    Representation of two muscle response vectors.

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    <p>SI is the cosine of the angle between the RV and PRV vectors (θ). This value compares the relative distribution across the set of muscles chosen for the task. A SI value of 1.0 means that the test participant's RV had an identical distribution of sEMG activity across muscles to the neurologically intact group PRV for that task. In the 2D case the ratio of activity in muscle X and muscle Y is the same. For two muscles (X and Y) the vectors are 2 dimensional as shown here. The vector sum is the response vector. A third muscle would be represented by a vector component perpendicular to the page. For more muscles, the formulae are extended, but visualisation in 3D space is no longer possible.</p

    Satellite photographs (Airbus DS 2014) of the two trial sites with information overlaid to show the location of treatment blocks and monitoring lines.

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    <p>The ground baiting blocks are indicated by the red lines, and adjacent areas treated with aerial 1080 poisoning are indicated by yellow lines (arrows indicating continuation beyond the limits of the figure). Chewcard lines are shown in purple and trap lines in blue. The two images have different scales.</p
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