Abstract The purposes of the present research were to evaluate (1) the value of ultrasonographically guided fine-needle aspiration biopsy (US-FNAB) in nonpalpable suspicious breast lesions, (2) the preoperative use of methylene blue staining in nonpalpable galactographically suspicious breast lesions, (3) the determinants of positive histologic margins and residual cancer in wire-guided biopsy (WGB) of nonpalpable breast cancer and in lumpectomy for early breast cancer and the determinants of positive radiologic margins and the correlation between radiologic and histologic margins and residual disease in WGB of nonpalpable breast cancer, (4) the assessment of lumpectomy margins by touch preparation cytology in early breast cancer, and (5) the cosmetic outcome of WGB performed for benign breast lesions. The sensitivity and specificity of US-FNAB in 90 nonpalpable breast lesions were 84% and 93%, respectively. Preoperative methylene blue staining was successful in 22 out of 30 (73%) cases, making subsequent selective minimal volume microdochectomy easy to perform. Multivariate analysis of 21 prospectively evaluated variables was done after 71 WGBs of nonpalpable breast cancer followed by 54 re-excisions. Large mammographic lesions had more often positive radiologic margins. Multifocality, large pathologic size and superficial excision were related to positive histologic margins and multifocality to residual disease in re-excisions. The sensitivity and specificity of specimen radiography for predicting histologic margins were 38% and 81% and those for residual disease 27% and 79%, respectively. The corresponding figures for histologic margins in predicting residual disease were 85% and 59%, respectively. In a prospective series of 55 consecutive lumpectomies for early breast cancer, positive histologic margins were found more often in the presence of intraductal cancer and if the pathologic size of the index tumor was large. Residual disease was found in 38% of the cases with positive and in 15% of the cases with negative histologic margins. A multifocal and nonpalpable index tumor predicted residual cancer in 34 re-excision specimens. The sensitivity and specificity of touch preparation cytology in predicting histologic margins were 38% and 85%, respectively. In WGB, the overall cosmesis 6 months after surgery was satisfactory in 75 % of the 101 prospectively evaluated patients with benign proven lesions. Cosmesis was poorer after deep excisions and complications. The results indicate that US-FNAB is a useful tool in evaluating nonpalpable suspicious breast lesions. Preoperative methylene blue staining crucially facilitates selective minimal volume microdochectomy in three-quarters of cases. To obtain free margins in WGB, mammographically and pathologically large lesions should be removed with wider excisions extending down to the fascia. However, radiologic margins in WGB and histologic margins both in WGB and in lumpectomy for early breast cancer may be misleading. Re-excision of the biopsy site of multifocal tumors after WGB and lumpectomy should be considered. This is also important after superficial excision in WGB due to the considerable risk of residual disease. Touch preparation cytology cannot be recommended for the assessment of margins in lumpectomy specimens of early breast cancer. Cosmetic outcome after WGB of benign breast lesions is satisfactory in 75 % of cases. Deep excisions and complications endanger the cosmetic outcome. Preoperative biopsy and tumor localization methods have proven their utility; nevertheless, free margins are still difficult to obtain and to evaluate accurately. The surgeon may often be forced to choose between free margins and an acceptable cosmetic outcome.

Oral cancer accounts for an estimated 650,000 new cases annually with a high mortality rate of approx. 50%. Oral cancer is typically treated with a combination of surgery, radiation and chemotherapy, but patients suffer from high recurrence rates due to delayed detection and invasiveness of the disease. Surgical standards require surgeons to resect a margin of healthy tissue surrounding cancerous tissue in order to reduce the rate of recurrence. Frozen section (FS) analysis is a common intraoperative technique for examination of surgical margins, but is limited in its sensitivity of detecting positive margins of resected tissue (especially in deep margins where most positive sites originate). Elastic Scattering Spectroscopy (ESS) is a fiber optic based backscattering optical technique which utilizes a small source detector separation allowing for examination of subcellular changes in tissue. In addition, ESS is a point measurement technique making it impossible to take a grid of coordinated measurements over a tissue surface. ESS has been used extensively for the classification of cancerous tissue in vivo, but current instrumentation limits the physical and financial availability of ESS devices across various clinical studies. The goal of this thesis is the design and implementation of a low cost, portable and modular ESS device that allows for scanning across an area of tissue for the quantification and assessment of deep margins of resected oral cancer samples. A low-cost ESS device has been developed and validated for use across various clinical studies which utilize ESS. A scanning module has been developed to allow for imaging of resected tissue over an area of 1cm2 with a pixel resolution down to 100 μm. This system will be utilized in a clinical study to assess deep margins of resected oral cancer tissue to test the feasibility for using ESS as an adjunct for FS.

Increased volatility of agricultural commodity prices as well as market linkages between the agricultural and energy markets expose producers to different types of systematic price risk. Producers that operate on margins involving both input and output price uncertainty are perhaps the most adversely affected by these volatility changes. The beef cattle feeding industry is one such example. This research focuses on how expected margins in the beef cattle backgrounding and finishing stages are affected by output and input price uncertainty.

No description available.

No description available.

Canada’s Boreal Plains peatlands comprise 2.1% of the world’s terrestrial carbon store and are vital water supplies for adjacent upland ecosystems in this sub-humid climate. Projections indicate that future drought and wildfire events will be more frequent and severe, enhancing moisture deficits and threatening the functional role of peatlands as net carbon sinks. Peatland margins existing at the peatland-upland interface have been identified as deep smouldering hotspots on the landscape, where margin carbon loss accounts for 50 to 90% of total peatland carbon loss, dependent on hydrogeological setting. Previous chronosequence analysis of peatland bog recovery from wildfire disturbance has chronicled a return to carbon sink status within 20 years, but has not included margins nor peatlands located in coarse or heterogeneous-textured hydrogeological settings with varying degrees of groundwater connectivity. This analysis identifies and describes margin vegetation communities and recovery trajectories with time since fire and across hydrogeological settings. No significant differences were identified in margin area over time or margin peat depths across hydrogeological settings. Margin canopy composition consists of mixed coniferous and broadleaf deciduous species, with enhanced litterfall characterizing the dominant early to mid successional ground layer composition. Both peatland bog middle and margin vegetation communities were found to be dominated by feathermoss growth ~60 years following wildfire, which represents an accelerated trajectory from previous chronosequence analyses. Increased peatland and margin fuel loads with time since fire are also demonstrated using aboveground biomass calculations. Restoration practitioners can use this study to identify recovery milestones and altered trajectories, with their associated feedbacks, that perpetuate a broadleaf canopy and limited Sphagnum moss paludification. Fire managers should include confined peatlands in coarse-textured hydrogeological settings with deep smouldering margins in their management considerations and consider intervention (forest treatments) to open the canopy and prevent legacy carbon losses by severe wildfires. / Thesis / Master of Science (MSc)

This dissertation describes two essays in empirical international trade, focusing on trade costs and the pattern of trade along the intensive and extensive margins. In the first essay, I study the barriers that impede international trade. In the second paper, I examine the growth of U.S. agricultural trade in detail describing how U.S. agriculture and food trade has expanded along the margins. The first chapter introduces a relatively straightforward, yet empirically powerful, manipulation of the gravity equation. The gravity model has been dubbed the work horse model of empirical trade, and thus is a suitable foundation from which to derive an indirect measure of largely unobservable 'iceberg' trade costs. In this paper, I solve a sector level version of the gravity equation and study the pattern of agricultural trade costs and factors that impede world agricultural trade growth over a long time series, 1986-2011. In addition, I estimate sector-specific elasticity of substitution which is a key parameter in the computation of trade cost. In the second essay, I examine the growth of world and U.S. agricultural exports along the intensive and extensive margins of international trade over the period 1986 to 2010. The purpose of this essay is to decompose the growth of world and U.S. agricultural trade using qualitative methods from the marketing literature (i.e., market expansion grids) but modified to fit bilateral trade relationships and a theoretical index to measure the margins of trade at a single point in time. In addition, we examine often overlooked channels by which U.S. agricultural exports have expanded using very detailed agricultural product lines. Using information related to the pattern of a trade rather than trade volume itself, I estimate how much starting a trade relationship with a new partner or in a new product variety matters to agricultural trade growth and then conclude with a set of stylized facts to inform current theory. / Ph. D.

本論文的研究對象為中國內地證券市場于2010 年3 月31 日開放的融資融券業務，試分析該創新業務是否對中國股市的價格發現功能帶來了有效的改善。筆者將所有符合融資融券條件的股票，以其近日的成交量進行篩選以構成新的證券投資組合，并計算它們在未來一段時間內的投資回報率。該研究的結果顯示，不同於美國等西方市場，中國融資（券）多的股票並未在未來的一定時間段里顯示出比融資（券）少的股票有更強（弱）的盈利能力。從而表明在內地股市中，無論是融資者還是融券者，都無法有效地預測未來一段時間內股市的走向。另外，通過比較融資融券業務占每日成交量的比重，亦可發現內地的融資業務的發展遠超融券業務的發展，使優化“單邊市場“的進程受到影響。根據以上兩個發現，筆者認為到2012 年為止，融資融券業務尚未有效的改善中國內地股市的價格法相功能，有悖于股市監管機構開展此業務時的最初目的。 / This paper studies the margin trading, including both margin purchase and short sale in mainland China markets, which was not opened until Mar 31st, 2010. I attempt to determine how the new business will influence the mainland markets by examining whether the margin traders are informed or not about stock prices in their holding periods. By using data from Mar 31st, 2010 to Dec 31st, 2012, I find that the daily percentage of margin purchasing in trading volume is usually 600% more than that of short selling, which may aggravate the asymmetric level of mainland stock markets. In addition, by measuring the return of specially sorted trading portfolios based on stock margin trading activities in previous trading days, I find that both heavily margin purchased (shorted) stocks do not perform better (worse) than lightly margin purchased (shorted) ones in the following trading days, which is different from the findings in developed markets, where heavily shorted stocks underperform the lightly shorted ones, and indicates that both margin purchasers and short sellers in mainland markets are not well informed. My two findings imply that margin trading in the mainland may not efficiently improve the price efficiency mechanism in mainland markets by incorporating private information into markets, which is one of the top purposes of regulators when starting the business. / Detailed summary in vernacular field only. / Wu, Xueyi. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 56-57). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts aslo in Chinese. / Abstract --- p.i / 摘要 --- p.ii / Acknowledgment --- p.iii / Table of Content --- p.iv / Chapter 1. --- Introduction --- p.1 / Chapter 2. --- Literature Review --- p.3 / Chapter 2.1 --- Margin Trading, Informed Investors and Price Discovery --- p.3 / Chapter 2.2 --- Unbalanced development of margin purchase and short sale --- p.5 / Chapter 2.3 --- Other studies related to margin trading in China --- p.6 / Chapter 3. --- Chinese Market and Its Margin Trading Regulation --- p.8 / Chapter 3.1 --- Market instability and the purposes of introducing margin trading --- p.8 / Chapter 3.2 --- Undeveloped derivative markets and dominance of individual investors --- p.10 / Chapter 3.3 --- Implementation rules --- p.11 / Chapter 3.4 --- Simultaneous opening of margin purchase and short sale --- p.13 / Chapter 4. --- Empirical Method and Results --- p.15 / Chapter 4.1 --- Data and Methodology --- p.15 / Chapter 4.2 --- Margin Trading Summary --- p.16 / Chapter 4.3 --- Duration --- p.18 / Chapter 4.4 --- Correlation --- p.20 / Chapter 4.4.1 --- Contemporaneous Correlation --- p.20 / Chapter 4.4.2 --- Autocorrelation and cross-autocorrelation --- p.21 / Chapter 4.5 --- Cross-section of Margin Purchase and Short Sale and Their Future Returns --- p.24 / Chapter 4.5.1 --- Margin Purchase Returns of Different Sections --- p.24 / Chapter 4.5.2 --- Short Sale Returns of Different Sections --- p.27 / Chapter 4.5.3 --- Robust Check by Choosing Different Holding Periods --- p.29 / Chapter 5. --- Conclusion --- p.31 / Chapter Tables --- p.33 / Chapter Table 1 --- Market capitalization and turnover of mainland stock market --- p.33 / Chapter Table 2 --- Distribution of accounts based on market value --- p.34 / Chapter Table 3 --- Summary statistics for margin trading in mainland markets --- p.35 / Chapter Table 4 --- Industry breakdown of margin purchase and short sale --- p.37 / Chapter Table 5 --- Duration and turnover rate of margin trading --- p.42 / Chapter Table 6 --- Contemporaneous correlation between margin trading and stock performance --- p.43 / Chapter Table 7 --- Autocorrelation and cross-autocorrelation between margin purchase and stock return --- p.45 / Chapter Table 8 --- Autocorrelation and cross-autocorrelation between short sale and stock return --- p.47 / Chapter Table 9 --- Margin purchase returns by using special sorted portfolios --- p.49 / Chapter Table 10 --- Short sale returns by using special sorted portfolios --- p.51 / Chapter Table 11 --- Margin purchase returns by choosing different holding periods --- p.53 / Chapter Table 12 --- Short sale returns by choosing different holding periods --- p.54 / Chapter Table 13 --- Number of securities firms approved for margin trading --- p.55 / References --- p.56

Graduation date: 1992

Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 163-171) / Microfiche. / xi, 171 leaves, bound ill., maps 29 cm