111 research outputs found
Geology, fluid inclusion and stable isotope study of the Yueyang Ag-Au-Cu deposit, Zijinshan orefield, Fujian Province, China
No full textThe large Yueyang Ag-Au-Cu deposit is commonly regarded as a low-sulfidation epithermal deposit in the Zijinshan orefield, Fujian Province, southeastern China. The Ag-Ag-Cu orebodies hosted in the Zijinshan granitic batholith are mainly stratoid and lens in shape, and controlled by a series of NW-trending listric faults with shallow dip angles. Four mineralization stages are recognized on the basis of mineral assemblage, ore fabrics, and crosscutting relationships of the ore veins, namely: pre-ore (pyrite + sericite + quartz chlorite), main Cu (chalcopyrite + pyrite + sericite + quartz +/- bomite), main Ag-Au (Ag and Au minerals + pyrite + quartz + adularia +/- calcite +/- apatite +/- chalcopyrite +/- galena +/- sphalerite) and post-ore (quartz +/- chalcedony +/- calcite) stages. Fluid inclusions (Fis) in the deposit include aqueous liquid-rich (WL-), aqueous vapor-rich (WV-), and minor carbonic (C-) and daughter mineral-bearing (S-) type ones. WL-subtype is the main inclusion type in the Yueyang deposit, accounting for more than 90% in proportion in each stage. Minor WV-subtype inclusions occur in both the main Cu and Ag stages, while the C type and S-type ones are only observed in the main Cu stage. Fluid inclusion and H-O isotope study indicated that the ore-forming fluid of the main Cu stage is primarily magmatic vapor, which further underwent fluid boiling and mixing with meteoric water, while the ore-forming fluid of the main Ag stage is meteoric water-dominated, and the precipitation of silver and gold was mainly resulted from fluid boiling and the precipitation of other sulfides. On the basis of the aforementioned geological, fluid inclusion and stable isotope studies, we proposed a two-stage model for the Yueyang deposit, including a magmatic vapor-related porphyry type Cu mineralization and meteoric water-related low-sulfidation epithermal Ag-Au-Cu mineralization, although the porphyry Cu mineralization is very limited in scale. The mineralization and exhumation depths of the Yueyang deposit are estimated to be 448 527 m and 18 97 m, respectively. By comparison with the exhumation depths of other deposits in the Zijinshan orefield, it is suggested that more epithermal deposits could be found in the southwest of the orefield due to less uplift and exhumation therein. (C) 2017 Elsevier B.V. All rights reserved.National Natural Science Foundation of China [41502083]; Ministry of Science and Technology of China [2009BAB43B04]; Zijin Mining Co. Ltd.SCI(E)ARTICLE254-2708
Essays on information and frictions in financial markets
No full textThe first chapter studies the dynamics of information acquisition and uncertainty in a noisy rational expectations model. Investors choose to acquire most information at times when uncertainty and risk premia are high; this choice feeds back and endogenously reduces subsequent uncertainty. Within the model, uncertainty can be measured directly from risk-neutral variance—analogous to the VIX index—so this translates into the concrete prediction that risk-neutral variance mean-reverts rapidly following spikes in volatility, as is observed empirically. The cyclicality of information acquisition depends on the skewness of the underlying asset: if the market is negatively skewed, market-level information acquisition is countercyclical. Conversely, information acquisition and risk premia are high following good news for positively skewed assets such as individual stocks, which gives rise to momentum in the stock market. In the second chapter, my co-author and I consider an economy populated by investors with heterogeneous preferences and beliefs who receive non-pledgeable labor incomes. We study the effects of collateral constraints that require investors to maintain sufficient pledgeable capital to cover their liabilities. We show that these constraints inflate stock prices, give rise to clusters of stock return volatilities, and produce spikes and crashes in price-dividend ratios and volatilities. Furthermore, the mere possibility of a crisis significantly decreases interest rates and increases Sharpe ratios. The stock price has a large collateral premium over non-pledgeable incomes. Asset prices are in closed form, and investors survive in the long run. The third chapter studies information acquisition with a long-lived risky asset that generates dividends in each period. The investors can either be informed or uninformed, and the informed investors actively acquire information on the timevarying dividend growth rate. Informed investors take short positions in the variance swap to realize their informational advantage; the uninformed investor takes a long position to hedge his risks. Serial correlation of returns is decreasing in information acquisition of informed investors. Low uncertainty induces investors to acquire less information and decreases the cross-sectional dispersion of beliefs in expected returns
Essays on information and frictions in financial markets
No full textThe first chapter studies the dynamics of information acquisition and uncertainty in a noisy rational expectations model. Investors choose to acquire most information at times when uncertainty and risk premia are high; this choice feeds back and endogenously reduces subsequent uncertainty. Within the model, uncertainty can be measured directly from risk-neutral variance—analogous to the VIX index—so this translates into the concrete prediction that risk-neutral variance mean-reverts rapidly following spikes in volatility, as is observed empirically. The cyclicality of information acquisition depends on the skewness of the underlying asset: if the market is negatively skewed, market-level information acquisition is countercyclical. Conversely, information acquisition and risk premia are high following good news for positively skewed assets such as individual stocks, which gives rise to momentum in the stock market. In the second chapter, my co-author and I consider an economy populated by investors with heterogeneous preferences and beliefs who receive non-pledgeable labor incomes. We study the effects of collateral constraints that require investors to maintain sufficient pledgeable capital to cover their liabilities. We show that these constraints inflate stock prices, give rise to clusters of stock return volatilities, and produce spikes and crashes in price-dividend ratios and volatilities. Furthermore, the mere possibility of a crisis significantly decreases interest rates and increases Sharpe ratios. The stock price has a large collateral premium over non-pledgeable incomes. Asset prices are in closed form, and investors survive in the long run. The third chapter studies information acquisition with a long-lived risky asset that generates dividends in each period. The investors can either be informed or uninformed, and the informed investors actively acquire information on the timevarying dividend growth rate. Informed investors take short positions in the variance swap to realize their informational advantage; the uninformed investor takes a long position to hedge his risks. Serial correlation of returns is decreasing in information acquisition of informed investors. Low uncertainty induces investors to acquire less information and decreases the cross-sectional dispersion of beliefs in expected returns
Testing the effectiveness of treatment for cancers for which the endpoint is survival using Bayesian subgroup analysis
No full textReducing dependency: Corporate ESG profiles and customer structure
No full textUnderstanding the organizational consequences of corporate ESG and its underlying mechanisms is essential for corporate management to develop sustainable strategies, and it is a topic of growing interest in academia. This study, utilizing a sample of Chinese A-share listed firms from 2010 to 2019, examines the impact of corporate ESG profiles on customer structure. We demonstrate that superior ESG profiles (primarily the social and governance aspects) contribute to reducing customer concentration. This effect is achieved by enhancing firm reputation and employee efficiency, thereby increasing market competitiveness and market share. This effect is more pronounced in firms that invest heavily in advertising and have employees committed to long-term goals. Furthermore, we discover that ESG-driven changes in customer concentration led to additional organizational outcomes, including enhanced bargaining power over customers, improved financial performance, and reduced operational risk. In conclusion, our evidence suggests that ESG significantly shapes a firm's customer structure and, consequently, its operations
When no news is good news: Multidimensional heterogeneous beliefs in financial markets
No full textWe demonstrate the asset pricing implications of investors' belief heterogeneity in the frequency of news arrival and its joint impact with heterogeneous beliefs about news content. Investors trade volatility derivatives against each other to speculate on the rate of news arrival: greater disagreement of this kind gives rise to more extreme derivative positions. When disagreement about news arrival frequency is low, volatility exhibits mean reversion because extreme optimists and pessimists incur substantial wealth losses amid intense market swings. In contrast, high disagreement about the news arrival rate leads to volatility persistence. When news is absent in such environments, volatility sellers dominate, and extreme payoffs are underweighted in the formation of market expectations, resulting in lower implied volatility. In this context, "no news" effectively becomes good news for risky asset valuations
Zero distribution of finite order Bank--Laine functions
No full textIt is known that a Bank-Laine function is a product of two normalized
solutions of the second order differential equation ,
where is an entire function. By using Bergweiler and Eremenko's method
of constructing transcendental entire function by gluing certain
meromorphic functions with infinitely many times, we show that, for each
and each , there exists a Bank--Laine
function such that with and being two entire
functions such that and ,
respectively. We actually provide a simpler construction of the special
Bank--Laine functions given by Bergweiler and Eremenko.Comment: arXiv admin note: text overlap with arXiv:1510.05731 by other author
Collateral constraints and asset prices
No full textWe study the effects of collateral constraints in an economy populated by investors with nonpledgeable labor incomes and heterogeneous preferences and beliefs. We show that these constraints inflate stock prices and generate spikes and crashes in price-dividend ratios and volatilities, clustering of volatilities, and leverage cycles. They also lead to substantial decreases in interest rates and increases in Sharpe ratios when investors are anxious about hitting constraints due to production crises in the economy. Furthermore, stock prices have large collateral premiums over nonpledgeable incomes. We derive asset prices and stationary distributions of the investors' consumption shares in closed form
The genes slyA, STM3120 and htrA are required for the anticancer ability of VNP20009
No full textabstract: VNP20009 is a very effective anti-cancer agent and can specifically target tumors and inhibit tumor growth. It was assumed that the tumor targeting ability of VNP20009 correlated to its anticancer capacity. However, our observation contradicted to this assumption. Three VNP20009 mutant strains (ΔslyA, ΔSTM3120 and ΔhtrA) with reduced fitness in normal tissues and unchanged fitness in tumors partially or completely lost their anti-cancer capacities. The genes slyA, STM3120 and htrA were required for survival within macrophages and were indispensable for tumor microenvironment remodeling by VNP20009. The infiltration of immune cells occurred less in the tumors of mice infected with the mutant strains. In addition, the mRNA levels of TNF-α and IL-1β were significantly decreased in the tumors of mice treated with the mutant strains. Our results indicate that the immune responses elicited by bacteria rather than the bacterial titer in tumors play a “decisive” role in VNP20009-mediated bacterial cancer therapy, which provides a novel perspective for the underlying mechanism of bacterial cancer therapy.The final version of this article, as published in Oncotarget, can be viewed online at: http://www.impactjournals.com/oncotarget/index.php?journal=oncotarget&page=article&op=view&path%5b%5d=1321
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