151 |
An Enhanced Resolution Spaceborne ScatterometerLong, David G. 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Spaceborne wind scatterometers are designed principally to measure radar backscatter from the ocean's surface for the determination of the near-surface wind direction and speed. Although measurements of the radar backscatter are made over land, application of these measurements has been limited primarily to the calibration of the instrument due to their low resolution (typically 50 km). However, a recently developed resolution enhancement technique can be applied to the measurements to produced medium-scale radar backscatter images of the earth's surface. Such images have proven useful in the study of tropical vegetation3 as well as glacial5 and sea6 ice. The technique has been successfully applied2 to Seasat scatterometer (SASS) data to achieve image resolution as fine as 3-4 km. The method can also be applied to ERS-l scatterometer data. Unfortunately, the instrument processing method employed by SASS limits the ultimate resolution which can be obtained with the method. To achieve the desired measurement overlap, multiple satellite passes are required. However, with minor modifications to future Doppler scatterometer systems (such as the NASA scatterometer [NSCAT] and its follow-on EoS-era scatterometer NEXSCAT) imaging resolutions down to 1-2 km for land/ice and 5-10 km for wind measurement may be achieved on a single pass with a moderate increase in downlink bandwidth (from 3.1 kbps to 750 kbps). This paper describes these modifications and briefly describes some of the applications of this medium-scale Ku-band imagery for vegetation studies, hydrology, sea ice mapping, and the study of mesoscale winds.
|
152 |
ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2Otten, Gilles P. P. L., Snik, Frans, Kenworthy, Matthew A., Keller, Christoph U., Males, Jared R., Morzinski, Katie M., Close, Laird M., Codona, Johanan L., Hinz, Philip M., Hornburg, Kathryn J., Brickson, Leandra L., Escuti, Michael J. 12 January 2017 (has links)
We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of 2-5 mu m. and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The coronagraph manipulates the phase in the pupil to produce three beams yielding two coronagraphic point-spread functions (PSFs) and one faint leakage PSF. The phase pattern is imposed through the inherently achromatic geometric phase, enabled by liquid crystal technology and polarization techniques. The coronagraphic optic is manufactured using a direct-write technique for precise control of the liquid crystal pattern. and multitwist retarders for achromatization. By integrating a linear phase ramp to the coronagraphic phase pattern, two separated coronagraphic PSFs are created with a single pupil-plane optic, which makes it robust and easy to install in existing telescopes. The two coronagraphic PSFs contain a 180 degrees dark hole on each side of a star, and these complementary copies of the star are used to correct the seeing halo close to the star. To characterize the coronagraph, we collected a data set of a bright (m(L) = 0-1) nearby star with similar to 1.5 hr of observing time. By rotating and optimally scaling one PSF. and subtracting it from the other PSF, we see a contrast improvement by 1.46 magnitudes at 3.5 lambda/D. With regular angular differential imaging at 3.9 mu m, the MagAO vector apodizing phase plate coronagraph delivers a 5 sigma Delta mag contrast of 8.3 (= 10(-3.3)) at 2 lambda/D and 12.2 (= 10(-4.8)) at 3.5 lambda/D.
|
153 |
Participation and role of EU in resolving Nagorno-Karabakh ConflictHasanov, Ahmad January 2014 (has links)
The thesis analyses the conflict between Azerbaijan and Armenia over the region of Nagorno-Karabakh which both parties claim to be their historical territory. The thesis explains how the conflict started and continued with a full-scale military conflict between Azerbaijan and Armenia, which is commonly referred to as the Nagorno-Karabakh War. One of the most important chapter of the thesis is the description of roles played by foreign mediators such as Russia, Kazakhstan, Iran and Turkey. All those countries pursued their own geopolitical and economic goals in the region, and wished to actively participate in it in order to spread their influence. The European Union has constantly been playing an important role in settlement of the Nagorno-Karabakh conflict thanks to its active involvement in all peacekeeping and mediation processes in the region. Nonetheless, despite all international efforts, the conflict in Nagorno-Karabakh still continues as of today, and the parties cannot come to any compromise due to the antagonistic nature of their territorial disputes for Nagorno-Karabakh. Both, Azerbaijan and Armenia have started actively deploying their troops on the mutual borders, which raises fears among the international community that a new war for Nagorno-Karabakh might start already in the near future.
|
154 |
Image reconstruction for emission optical projection tomographyDarrell, Alexander Louis January 2010 (has links)
Emission Optical Projection Tomography (eO PT) is a relatively new imag- ing modality that bridges a gap between micro Magnetic Resonance Imag- ing and Confocal Laser Scanning Microscopy. eO PT can be used to image the anatomy and gene expression of intact biological specimens at high resolution and thus provides an alternative to time consuming methods such as serial sectioning. Tomographic image reconstruction for eOPT is currently performed using the Filtered Back Projection algorithm which, while being fast, does not account for the physics of image formation and thus can result in reconstructions of reduced resolution and questionable quantitative consistency. This thesis describes work that was done on eOPT in three areas, including image formation, tomographic reconstruction, and memory savings, the latter of which were required to bring implementation of 3D iterative reconstruction algorithms within reach for the relatively high-resolution eO PT imaging modality. In the area of image formation, measurements were taken to reveal the effects of optical blurring, diffraction and charge-coupled device (CCD) camera noise. Accurate models of each of these phenomena were developed and compared against the measurements. The subject of image reconstruction was first addressed with a modi- fication to the FBP algorithm designed to correct for the quantitative inaccuracies suspected of being introduced by the FBP algorithm when reconstructing specimens consisting of very fine detail. This was done by incorporating the quantitative aspects of the model of image formation into the FBP algorithm. The full model of image formation was incorpo- rated into the iterative Maximum Likelihood Expectation Maximisation (MLEM) algorithm. The third strand of this thesis focuses on various memory saving meth- ods developed to enable the implementation and testing of a variation of MLEM known as the Ordered Subsets Expectation Maximisation (OSEM). , Without such memory saving methods, the implementation of an iterative 3D reconstruction algorithm such as MLEM or OSEM using a full model of image formation would have remained beyond the capacity of modern computers for the foreseeable future, requiring several Terabytes of RAM. Comparisons were made between the quality of and the time required to produce FBP and OSEM reconstructions of the same data sets given the availability of limited computing resources. The feasibility of adopting OSEM reconstructions as an alternative to FBP reconstructions was dis- cussed, based on the use of currently available cutting edge computing hardware.
|
155 |
Screening for domestic violence in family mediation : an investigation into how mediators manage disclosures of domestic abuse and associated emotionsMorris, Paulette Elaine January 2015 (has links)
This thesis explores the practice of family mediators when screening for domestic violence during mediation. Mediation Information and Assessment Meetings (MIAMs) and Joint Mediation Meetings (JMs) were recorded between April 2010 and January 2011, by four mediators who mediate for National Family Mediation (NFM) affiliated services in the South of England. These meetings were analysed from the mother’s perspective, using qualitative and quantitative analysis. The themes for analysis were taken from the Duluth Domestic Abuse Intervention Programme (DDAIP). It was found that mediators did initially screen for domestic violence during the MIAM, using the guidelines published by NFM; that screening was focused on the clients perception of the abuse and not the mediators interpretation of the abuse. The published expectation for screening to be ongoing throughout mediation was explored during the analysis of the joint meetings. There was evidence that abusive behaviours were alleged or inferred during those meetings and there was also evidence that the abusive behaviours and the emotions expressed by the mothers were managed by the mediators. There was no clear evidence that the mediators were proactively screening for domestic violence during the joint meetings save for reacting to and managing the impact and effect of the negative behaviours. This study concludes that mediators do not routinely screen for domestic violence during joint meetings, therefore guidance and training for ongoing screening during joint mediation meetings is needed. The current guidance and policy for screening needs to be reviewed.
|
156 |
Diplomacy Becomes Them: Mediating Knowledge in Spaces of Conflict ResolutionChristiansen, Poul Erik 21 February 2019 (has links)
This dissertation explores informal means of convening various foreign policy professionals in conflict resolution discussions, taking two quite different case studies: the Pugwash Conferences, a long-standing transnational non-governmental organization; and the Ottawa Dialogue, a more recent suite of projects. Although conventionally viewed through the rubric of ‘Track Two’, this thesis instead tackles the subject of unofficial diplomacy through a conceptual framework derived from critical and sociological work in International Relations theory. By taking a practice-based approach, the research reveals that what is actually done in the spaces of unofficial diplomacy not only has a diplomatic purpose at root but in fact can be seen to reproduce a diplomatic logic in how certain tasks are performed. The dissertation shows the intrinsic liminality of these informal, unofficial activities to the corridors of power and policymaking and, in this way, helps elaborate how the emergent landscape of diplomacy is impacted by various actors and changing practices.
To understand why such processes appear around international conflict, the thesis calls attention to investigating how they are used by those who participate. The approach brings into focus the constitution of professional social networks that emerge in spaces left out of limelight, where various experts contest, debate, and refract policy knowledge. Through the eyes of these non-traditional actors, the thesis problematizes diplomacy as a solely state-based authority, insisting that we must look to the close imbrication of government representatives in putatively non-state activities to understand their contribution to global governance. Developed through an immersion and engagement of ten years with the very people who do the work, this project brings together several theoretical and methodological perspectives to make sense of a complex data-set and bridge a number of disciplinary gaps.
|
157 |
An investigation of aspects of normal and abnormal wound resolutionBrown, Nicola Jane January 1998 (has links)
Keloids are classically regarded as scars that `outgrow the boundary of the original injury'. Ambiguous data concerning certain characteristics of keloid fibroblasts (such as proliferation rates and collagen production), however, have served only to confuse researchersT. he lack of an in vivo model and of detailed clinical accounts are added problems. In this study, a murine granulomatous tissue resolution model was used to investigate the profile of a number of cytokines suspectedto be involved in the aetiology of keloids. The results obtained from these experiments were then extrapolated to clarify the observations made in keloids. The results of these extrapolated comparisons revealed elevated levels of interleukin (IL)-4, IL-10, vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and transforming growth factor beta (TGF)-ß in keloid samples and decreasedle vels of interferon (IFN)-y and IL-2. The murine model was also used to investigate the implications of the low levels of IFN-y known to be present in the serum of keloid patients and shown here to be present in clinical samples. The results were found to support the hypothesis that the addition of IFN-y reduces the fibrosis so typical of keloids by rectifying the abnormality of the absence of IFNy content. The same model was used to provide evidence that the inhibition of VEGF activity in resolving wounds may halt the development of keloid lesions. The immunohistochemical profiles of cellular proliferation, apoptosis, lymphokines and cytokines for resolution (and, to a certain extent, the model) were used to compare with the abnormally resolved wounds which were available as clinical samples. Immunohistochemistry was also employed to describe the cellular nature of the clinical tissue samples in detail and to facilitate the development of the following hypothesis for keloid formation and propagation: lymphocytes migrate to the site of an (alleged) endogenous antigen present in the skin. The nature of these lymphocytes is characteristic of a type 2 immune response, they produce IL-4 (and IL-10) which in turn inhibit(s) the production of IFN-y and IL-2. Aside from this immunological response, wound resolution is taking place: fibroblasts are producing PDGF, EGF and TGF-ß to aid matrix remodelling and collagen synthesis. The provisional matrix is being vascularised by the action of VEGF, to allow the replenishment of nutrients; regression of blood vessels occurs through the action of an apoptosis-dependent mechanism, as does the 'normalisation' of fibroblastic populations. The keloid scar continues to grow after the cessation of resolution because the immune response to the 'endogenous' antigen continues and the lymphocytes continue to migrate to the site of the wound and continue to stimulate fibroblast proliferation and collagen production through the release of IL-4.
|
158 |
Studies of anorectal function using high resolution anorectal manometry in health and faecal incontinenceCarrington, Emma V. January 2017 (has links)
Faecal incontinence (FI) is a prevalent complaint in Western populations and causes significant disability. Impaired motor function of the anal canal is a common pathophysiological feature and assessment of sphincteric function with manometry is a routine part of symptom assessment. High-resolution anorectal manometry (HRAM) may provide a more detailed understanding of anorectal function, however its clinical utility has not been established. Aims The principal aims of this thesis were to: (1) Explore existing practices of anorectal manometry (2) Examine current evidence supporting the use of HRAM (3) Develop and validate a protocol for the performance of HRAM (4) Define normal values for traditional measures of sphincteric function using HRAM (5) Develop and validate novel measures of sphincteric function, and explore whether they improve diagnostic accuracy in patients with FI (6) Examine anorectal function over a prolonged period with HRAM to evaluate the phenomenon of anal sampling (referred to in this thesis as transient anal sphincter relaxations [TASRs]) Methods The following methods were used: (1) A worldwide survey of current practices of anorectal manometry (2) A systemic review of the literature (3) Prospective studies (both standard and prolonged) of anal function in healthy volunteers and patients with FI Results The practice of anorectal manometry is markedly variable internationally with no two centres surveyed employing the same methods. Within the 62 centres surveyed, there were 16 combinations of ways in which squeeze data were reported. A review of the literature demonstrated a growing evidence base for the use of HRAM however there is a paucity of data that confirm added benefits of HRAM over conventional manometry. A standardized protocol for HRAM was developed to allow the reporting of traditional measures of anorectal function. Novel measures derived from HRAM were developed which demonstrate increased sensitivity for the detection of impaired sphincteric control in patients with FI (sensitivity of traditional measure [conventional squeeze increment] 36% vs. 59% for the novel HRAM measure [5-second squeeze profile]). Transient anal sphincter relaxations (TASRs) were characterized using HRAM. In health, TASRs are often perceived by the individual as the urge to pass wind (39% of events) and their frequency increases following meal consumption. Conversely in FI, TASRs are a rare occurrence and are generally not perceived (only one patient (1/10 [10%]) with FI reported GI sensations associated with TASR events). Conclusions Anorectal manometry is in need of standardization. Novel measures derived from HRAM may improve diagnostic utility and further exploration of TASR characteristics might give insight into the pathophysiology of FI.
|
159 |
An Analysis of Conflict in Two HospitalsWashing, Harry Alfred 08 1900 (has links)
The primary problems of the study are to collect data on conflicts with respect to two hospitals. and to analyze such data in order to determine the seriousness of present intra- and intersubgroup conflicts and the subject matters and underlying causes of the more serious present subgroup conflicts. A comparative analysis of the respective subgroups in each hospital and a comparative analysis of the two hospitals in conflicts are also part of the study.
|
160 |
Resolving other-anaphoraNygren Modjeska, Natalia January 2004 (has links)
Reference resolution is a major component of any natural language system. In the past 30 years significant progress has been made in coreference resolution. However, there is more anaphora in texts than coreference. I present a computational treatment of other-anaphora, i.e., referential noun phrases (NPs) with non-pronominal heads modi- fied by “other” or “another”: [. . . ] the move is designed to more accurately reflect the value of products and to put steel on more equal footing with other commodities. Such NPs are anaphoric (i.e., they cannot be interpreted in isolation), with an antecedent that may occur in the previous discourse or the speaker’s and hearer’s mutual knowledge. For instance, in the example above, the NP “other commodities” refers to a set of commodities excluding steel, and it can be paraphrased as “commodities other than steel”. Resolving such cases requires first identifying the correct antecedent(s) of the other-anaphors. This task is the major focus of this dissertation. Specifically, the dissertation achieves two goals. First, it describes a procedure by which antecedents of other-anaphors can be found, including constraints and preferences which narrow down the search. Second, it presents several symbolic, machine learning and hybrid resolution algorithms designed specifically for other-anaphora. All the algorithms have been implemented and tested on a corpus of examples from the Wall Street Journal. The major results of this research are the following: 1. Grammatical salience plays a lesser role in resolving other-anaphors than in resolving pronominal anaphora. Algorithms that solely rely on grammatical features achieved worse results than algorithms that used semantic features as well. 2. Semantic knowledge (such as “steel is a commodity”) is crucial in resolving other-anaphors. Algorithms that operate solely on semantic features outperformed those that operate on grammatical knowledge. 3. The quality and relevance of the semantic knowledge base is important to success. WordNet proved insufficient as a source of semantic information for resolving other-anaphora. Algorithms that use the Web as a knowledge base achieved better performance than those using WordNet, because the Web contains domain specific and general world knowledge which is not available from WordNet. 4. But semantic information by itself is not sufficient to resolve other-anaphors, as it seems to overgenerate, leading to many false positives. 5. Although semantic information is more useful than grammatical information, only integration of semantic and grammatical knowledge sources can handle the full range of phenomena. The best results were obtained from a combination of semantic and grammatical resources. 6. A probabilistic framework is best at handling the full spectrum of features, both because it does not require commitment as to the order in which the features should be applied, and because it allows features to be treated as preferences, rather than as absolute constraints. 7. A full resolution procedure for other-anaphora requires both a probabilistic model and a set of informed heuristics and back-off procedures. Such a hybrid system achieved the best results so far on other-anaphora.
|
Page generated in 0.0988 seconds