bluuebunny/crossref_metadata_2025 huggingface dataset:
FUNCTIONAL FORMS OF THE CAPITAL ASSET PRICING MODEL UNDER DIFFERENT MARKET RISK REGIMES
Authors: Ang James S. , Lai Tsong‐Yue
Published: March 2005

This paper demonstrates that, given the assumption that asset returns are generated by the linear market model, the same functional form for the capital asset pricing model can be derived via the simpler linear programming approach for the riskaverse, risk‐neutral, and risk‐loving market regimes.
OPTIONS ON U.S. TREASURY COUPON ISSUES
Authors: Finucane Thomas J.
Published: March 2005

Pricing models for options on default‐free coupon bonds are developed and tested under the assumption that the bond prices, rather than interest rates, are the underlying stochastic factors. Under the assumption that coupon bond prices, excluding accrued interest, follow a generalized Brownian bridge process, preference‐free, continuous‐time pricing models are developed for European put and call options, and a discrete‐time model is developed for American puts and calls. The empirical validity of the models is assessed using a six‐moth sample of daily closing prices.
THE IMPACT OF BOND RATING CHANGES ON COMMON STOCKS AND BONDS: TESTS OF THE WEALTH REDISTRIBUTION HYPOTHESIS
Authors: Zaima Janis K. , McCarthy Joseph
Published: March 2005

Past studies on the impact of bond rating changes have focused on bonds or stocks and the information content of rating change announcements. This paper examines both bonds and stocks and investigates the wealth redistribution effect as well as the existence of information content. The results imply that information content of “bad’ news dominates firm downgradings, while the wealth redistribution effect dominates firm upgradings. Furthermore, this study attributes the lack of information content for bond upgradings to the offsetting effects of wealth redistribution and information content.
The Pricing of When‐Issued Securities
Authors: Lamoureux Christopher G. , Wansley James W.
Published: March 2005

The observed pricing of when‐issued securities would seem to violate the law of one price in financial economics. Generally, when‐issued shares sell at a premium over the original shares during the short time when both are traded. This paper examines whether this observed premium could be due to a nonsynchronous trading problem, to the intensity of trading, to the exchange on which the shares are traded, to whether the shares are traded pre‐or‐post ‐negotiable commissions, or to the nature of the demand for when‐issued relative to the price setting of the specialist. Results indicate that most orders for when‐issued securities are buys, that these orders typically take place at the specialist's ask price, and that accounting for this trading mechanism explains the positive premium on when‐issued securities.
The Regression Tendencies of Betas: A Reappraisal
Authors: Kolb Robert W. , Rodriguez Ricardo J.
Published: March 2005

This paper reexamines the regression tendencies of beta. We show that common assertions in the literature about regression tendencies go well beyond the facts established by Blume. We analyze betas during the 1926–1985 period and examine the tendencies of betas to change. Extreme betas do tend to move toward the mean. However, betas near the mean in one period tend to move away from the mean. As a result, the distribution of betas is approximately stationary over time.
Interest Rate Risk at Commercial Banks: An Empirical Investigation
Authors: Mitchell Karlyn
Published: March 2005

This paper develops and estimates models to measure banks' exposure to interest rate risk. The models are estimated for the 1976–1983 period to determine whether banks' exposure to interest rate risk increased as a result of increased interest rate volatility and financial deregulation. The major findings are that banks changed their risk management strategies after 1979 and that total exposure to interest rate risk remained quite small.
Intertemporal Resolution of Uncertainty and Portfolio Behavior
Authors: Gandhi Devinder K. , Rashid Muhammad , Riener Kenneth D.
Published: March 2005

In this paper, it is shown that the early resolution of uncertainty improves the welfare of an investor who has utility defined over his intertemporal consumption. This result arises because the early resolution of uncertainty permits the investor the additional flexibility of rearranging his initial consumption. In contrast, if the investor has utility for terminal wealth, there is no effect on his portfolio behavior from the early resolution of uncertainty.
OSHA Sanctions and the Value of the Firm
Authors: Fry Clifford L. , Lee Insup
Published: March 2005

Citations by the Occupational Safety and Health Administration (OSHA) against companies for violating health and safety regulations are shown in this study to induce declines in the values of the subject firms. The declines are immediate and significant responses to the announcement of the OSHA citation, following the pattern predicted for efficient markets. Because firm values fall by more than proposed fines, OSHA citations are apparently forerunners of additional and significant costs to be borne by subject firms, perhaps in the form of capital costs to remedy safety conditions or losses in related lawsuits. Our findings point toward OSHA citations as an important part of the business environment.
Liquidity and Stock Exchange Listing
Authors: Edelman Richard B. , Baker H. Kent
Published: March 2005

This study examines the pattern of stock price behavior for a sample of 71 firms that moved from NASDAQ and NASDAQ/NMS to the American Stock Exchange (AMEX) between 1982 and 1987. The study tests the liquidity gains hypothesis, which states that investors expect liquidity gains for the less liquid over‐the‐counter stocks but not for their more liquid counterparts after their listing on the AMEX. The results support the hypothesis by showing a significant difference between the two groups of stocks on the day the AMEX announced approval of the listing. Thus, companies with low liquidity are the largest beneficiaries of listing. The evidence provides little support for the anomalous negative pattern of returns during the post‐listing period reported in previous studies.
Flotation Cost Allowance Methodologies: A Synthesis Using Present Value Analysis
Authors: Berry S. Keith
Published: March 2005

This article demonstrates a consistency amongst several alternative flotation cost recovery methodologies using present value analysis. All of the recovery methodologies assume that the stockholder is made whole through time. The key difference among them is the temporal pattern of cost recovery. It is shown that the appropriateness of prospective application of a particular flotation methodology is dependent upon prior regulatory treatment. The article provides a framework for addressing the issues concerning the proper market price‐to‐book value ratio and the appropriateness of an adjustment even if a utility has no plans to sell new common stock.
A Generalization of the Tree Harvesting Paradigm
Authors: Rodriguez Ricardo J.
Published: March 2005

The tree harvesting paradigm finds the optimal length of each harvest cycle. Typically, only the extreme cases of one and infinite harvests are considered. We extend the model in two ways. First, we analyze an arbitrary number of harvest cycles and show that the optimal cycle length decreases monotonically with the number of cycles. Second, we relax the restrictive assumption requiring the disappearance of positive net present value opportunities as the final cycle is harvested. Instead, we assume these opportunities disappear after an exogenously fixed horizon. This simple change of assumptions produces solutions that may differ substantially from the traditional solutions.
The Risk of Banks Expanding Their Permissible Nonbanking Activities
Authors: III Elijah Brewer
Published: March 2005

Risk exposure is a central issue in the continuing debate over the wisdom of allowing bank holding comapanies to expand into nonbank activities. This paper examines the relation between bank holding company (BHC) risk and the composition of nonbank assets. The empirical evidence indicates that risk is negatively associated with the mix of BHC assets in permissible nonbank subsidiaries. The negative association between BHC risk and the mix of permissible nonbank activities appears to have positive implications for future deregulation.
Estimation Risk and Adaptive Behavior in the Pricing of Options
Authors: Barry Christopher B. , French Dan W. , Rao Ramesh K. S.
Published: March 2005

We consider the effects of uncertainty in the statistical parameters of the Gaussian process in the context of the Black‐Scholes option pricing model. With continuous time observation of returns, uncertainty about the variance disappears over any finite time interval, but uncertainty about the mean diminishes at the rate of 1/τ, where T is the length of the time interval of observation. In a market in which participants base their portfolio decisions on the predictive distribution of returns, option prices will be higher than in a market in which uncertainty in the mean is ignored. Even though the mean parameter, μ, is itself irrelevant in the Black‐Scholes model, uncertainty about μ affects option values under our behavioral assumptions.
Comparing Present Value Cost Differentials between Fixed‐ and Adjustable‐Rate Loans: A Mortgage Simulation
Authors: Tucker Michael
Published: March 2005

When a borrower chooses between a fixed‐rate and an adjustable‐rate loan, he is doing so based on expectations of future interest rates and the expected life of the loan. This paper demonstrates how Monte Carlo simulation can be employed to assist in decision making when the borrower is confronted with the choice of fixed or adjustable‐rate mortgages. Present value costs of future mortgage payments are modeled using actual lending parameters offered over a 50‐month period, at varying borrower discount rates, and with different mortgage holding periods. The selection of a fixed‐rate or a variable‐rate mortgage is shown to be sensitive to mortgagee holding period and discount rates as well as to market conditions.
Inflation Uncertainty, Real‐Interest‐Rate Uncertainty, and the Liquidity Premium on Government Bonds
Authors: Palmon Oded , Parker Jeffrey
Published: March 2005

This paper shows that the components of uncertainty about nominal interest rates, real‐rate uncertainty and inflation uncertainty, have different effects on the liquidity premium. An increase in inflation uncertainty should increase the equilibrium liquidity premium because investors reduce the effect of inflation uncertainty on the riskiness of their portfolios by holding more short‐term bonds. In contrast, an investor can reduce the effects of uncertainty about future ex‐ante real rates on portfolio return by matching more closely the maturity dates of the bonds held with the date on which the portfolio is to be liquidated for consumption purposes. Thus, the effect of an increase in real‐rate uncertainty on the equilibrium liquidity premium is ambiguous, depending on the relative magnitudes of long‐term and short‐term saving and the proportions of short‐term and long‐term bonds issued by the government.
Estimating Systematic Risk with Daily Security Returns: A Note on the Relative Efficiency of Selected Estimators
Authors: Corrado Charles J. , Schatzberg John D.
Published: March 2005

This paper utilizes asymptotic analysis and daily security returns to examine the estimation efficiency of two unbiased robust estimators compared with ordinary least squares. Our results demonstrate a relative efficiency gain for a nonparametric rank estimator and a relative efficiency loss for the minimum absolute deviation estimator when estimating the systematic risk of securities using daily security returns.
The Role of Sectoral Demand in Influencing Tax‐Exempt Bond Yields: A Reexamination
Authors: Marlin Matthew R.
Published: March 2005

Despite an ongoing interest and a growing number of studies, the existence of segmentation (preferred habitats) in the tax‐exempt bond market remains controversial. Adding to the existing controversy are the impacts of recent tax reform legislation on the market and, consequently, on the viability of existing theories of yield determination. The present study first establishes that segmentation did exist through 1986, but that the influence of sectoral demand declined steadily throughout the 1980s. While the Tax Reform Act of 1986 resulted in a dramatic change in the pattern of sectoral demand, the results are not clear as to whether this implies an end to segmentation or simply a need to respecify the definitions of the different market segments.
Corporate Spin‐Offs and Closed‐End Funds in a State‐Preference Framework
Authors: Schnabel Jacques A.
Published: March 2005

Miller's clientele argument for market value subadditivity as an explanation for stockholder wealth gains in corporate spin‐offs and discounts from the net asset value of closed‐end fund shares is examined in the context of a simple state‐preference model. It is shown that binding short sales constraints induce value subadditivity and thus render Miller's clientele argument valid. This is true regardless of whether or not divergence of opinion among investors or state‐dependent utility functions exist. In the absence of binding short sales constraints, value additivity prevails and Miller's clientele argument is not viable. Although personal taxes are not considered in the model developed in this paper, it is shown that tax‐timing options reinforce the existence of value subadditivity.
Long‐Term Synthetic Puts
Authors: Hussain Riaz
Published: March 2005

We present the possibility of replicating the performance of a long‐term put, which is not available in the financial markets, by a set of other traded financial assets. First, a benchmark portfolio is formed out of one share of stock and one put on the stock with a certain exercise price and a long time until maturity. The general form of a portfolio, consisting of shares of stock, bonds, and options on the stock, is discussed, which is expected to perform like the benchmark portfolio. Then a class of these synthetic puts is examined to determine which type of synthetic put may dominate the others.
Comparison of Seasonal Anomalies across Major Equity Markets: A Note
Authors: Wilson Jack W. , Jones Charles P.
Published: March 2005

This paper reexamines the existence of seasonal anomalies in daily stock prices by integrating seasonal patterns into a single comprehensive model that captures the joint effects of seasonal variations for each of the three major markets. This model incorporates serial correlation and corrects for non‐normality by using robust regression techniques. Serial correlation is found to be important, as is the day of the week and the January variable. Furthermore, the Tuesday after a Monday holiday is significant for two markets using the robust technique (but not ordinary least squares). Finally, the day‐preceding‐a‐holiday effect is strongly significant.
Rates of Return on Art Objects, the Fisher Hypothesis, and Inflationary Expectations
Authors: Matsumoto Keishiro , Andoh Samuel K. , Hoban James P.
Published: March 2005

After surveying the evolution of the major methodologies in inflation hedging, this study presents a unique methodology that uses principal component factor analysis to separate the effects of variability in the real rate of return from the nominal rate of return. This approach allows the effects of both anticipated and unanticipated inflation on rates of return to be estimated more precisely. This study finds that art objects perform well in terms of average real rates of return and that the market, though not perfect, integrates anticipated inflation into the rates of return. However, unanticipated inflation is very often negatively related to the rates of return.
Some Tests of APT Mispricing Using Mimicking Portfolios
Authors: Kryzanowski Lawrence , Lalancette Simon , To Minh Chau
Published: March 2005

Cross‐sectional and time‐series tests using mimicking portfolios are used to assess the exactness of the APT with(out) a residual market factor. The first factor seems to be sufficient to span the efficient set, whether the model is estimated using (un)conditional variance‐covariance matrices that are (un)adjusted for nonsynchronous trading. Although the conditional standard deviations of the mimicking portfolios significantly explain the time‐variability of security volatilities, the residuals of the mean equation still exhibit heteroskedasticity. Similar results are obtained for portfolios of CAPM‐betaranked securities, and for randomly selected individual securities.
Voluntary Corporate Divestitures as Antitakeover Mechanisms
Authors: Loh Charmen , Bezjak Jennifer Russell , Toms Harrison
Published: March 2005

This paper examines the investor reaction to the use of corporate selloffs as antitakeover devices. The results show that firms subject to takeover speculations prior to the divestiture announcement experience insignificant changes in share prices while firms that have no takeover bid report significant wealth increases. The majority of the firms that undergo defensive divestitures remain independent one year after the selloffs. These findings are consistent with the authors' proposition that investors regard divestitures following rumors of takeover attempt as antitakeover strategies. On the other hand, investors perceive selloffs in a takeover‐free environment as a positive net present value decision.
A Reexamination of the Costs of Firm Commitment and Best Efforts IPOs
Authors: Chua Lena
Published: March 2005

Ritter [14] documents that best efforts IPOs are, on average, more costly to issue than firm commitment IPOs. This paper explains the phenomenon. Two component costs of going public are analyzed: underpricing and underwriter compensation. The model, based on a disagreement about firm value between underwriters and issuers, shows that underpricing is higher for firms using best efforts contracts as these firms, on average, are more speculative. Underwriter compensation is hypothesized to be higher for firms using best efforts contracts because of the high costs of market making for these firms in the aftermarket and the high distribution costs associated with the high risk of a failed offer. Empirical tests strongly support the propositions.
The Hedging Effectiveness of ECU Futures Contracts: Forecasting Evidence from an Error Correction Model
Authors: Ghosh Asim
Published: March 2005

In this paper, the traditional price change hedge ratio estimation method is extended by applying the theory of cointegration in case of hedging with European Currency Unit (ECU) futures contracts. Previous studies ignore the last period's equilibrium error and short‐run deviations. The findings of this study indicate that the hedge ratio estimated by the error correction method is superior to the one obtained from the traditional method, as evidenced by the likelihood ratio test and out‐of‐sample forecasts. Hedgers can control the risk of their portfolios more effectively at a lower cost.
The Impact of Sampling Errors on the Choice of Portfolio Efficiency Analysis Rules with Borrowing and Lending of a Riskless Asset
Authors: Brooks Robert , Kroll Yoram
Published: March 2005

This paper evaluates the impact of sampling errors on portfolio decisions using mean‐variance and stochastic dominance rules where riskless borrowing and lending opportunities exist. The paper establishes criteria for comparing the alternative decision rules (for example, mean variance versus stochastic dominance) according to their effectiveness and the cost (in sampling error terms). Normal distributions are simulated using various assumed means, standard deviations, correlations, and sample sizes. These simulations enable one to evaluate the impact of sampling errors on the potential effectiveness of the empirical stochastic dominance and mean variance rules that include borrowing and lending of a riskless asset.
Co‐Kurtosis and Capital Asset Pricing
Authors: Fang Hsing , Lai Tsong‐Yue
Published: March 2005

This paper examines the impact of co‐kurtosis on asset pricing using a four‐moment capital asset pricing model. It is shown that, in the presence of skewness and kurtosis in asset return distribution, the expected excess rate of return is related not only to the systematic variance but also to the systematic skewness and systematic kurtosis. Investors are compensated in higher expected return for bearing the systematic variance and the systematic kurtosis risks. Investors also forego the expected excess return for taking the benefit of increasing the systematic skewness.
Index Futures Trading and Stock Return Volatility: Evidence from the Introduction of Mid Cap 400 Index Futures
Authors: Galloway Tina M. , Miller James M.
Published: March 2005

The MidCap 400 stock index is used to provide new evidence on the relation between stock index futures trading and stock return volatility. The study documents a significant decrease in return volatility and systematic risk, and a significant increase in trading volume for the MidCap 400 stocks after the introduction of the MidCap index. A control sample of medium‐capitalization stocks, however, exhibits similar contemporaneous changes in these measures. The MidCap stocks and the control stocks also experience a significant decrease in volatility and an increase in volume after the introduction of MidCap 400 index futures. Thus, the study finds no difference in the behavior of the MidCap 400 stocks and the control stocks and no evidence of a relation between index futures trading and volatility in the stock market.
Board Composition, Managerial Ownership, and Firm Performance: An Empirical Analysis
Authors: Barnhart Scott W. , Rosenstein Stuart
Published: March 2005

Our objective is to examine the sensitivity of simultaneous equations techniques in corporate governance research. We model Tobin's Q, board composition, and managerial ownership using a three‐equation instrumental variables approach, with two specifications and four instruments. We find that the variables are jointly determined. However, results depend strongly on the specification of the model and the instruments. We conclude that results using simultaneous equations methods must be interpreted cautiously, OLS estimates should not be casually dismissed, and that sensitivity analysis is essential when estimating an empirical model whose structure is uncertain.
Risk adjusted discount rates and the present value of risky costs
Authors: Ariel Robert
Published: March 2005

In capital budgeting the correct risk adjusted discount rate for future cash flows is independent of whether the flow is a cost or a revenue. Contrary to a widely disseminated view in some popular textbooks and elsewhere, costs are not especially safe (nor risky), and accordingly costs should not be discounted at especially low risk adjusted discount rates. This paper analyzes capital budgeting within a portfolio model in which revenues and costs appear as “long’ and “short’ portfolio positions, respectively, and proves that costs are neither more nor less intrinsically risky than revenues.
The generation of stock market cycles
Authors: Bolten Steven E. , Weigand Robert A.
Published: March 2005

This paper demonstrates that the relation between stock market and business cycle dynamics can be conceptualized using a dividend discount model. The interaction of changes in earnings and interest rates throughout the economic cycle are shown to cause changes in the level of stock prices. This implies that monitoring and forecasting these factors can help explain and possibly predict stock price behavior over time.
The liquidity effects associated with addition of a stock to the S&P 500 index: evidence from bid/ask spreads
Authors: Erwin Gayle R. , Miller James M.
Published: March 2005

This study examines changes in stock liquidity, as measured by the bid/ask spread, when a stock is added to the S&P 500 Index. The paper presents evidence of a significant decrease in the bid/ask spread upon S&P 500 addition, however, this effect is limited to only those stocks that were not trading listed options. Further, the decrease in the bid/ask spread for nonoptioned stocks is accompanied by a significant and permanent increase in share price and trading volume. While optioned stocks experience a permanent increase in trading volume, they experience only a temporary increase in share price. The findings for optioned stocks support the hypothesis that the price and volume effects associated with S&P 500 addition derive from temporary price pressure. Findings pertaining to the nonoptioned stocks indicate that the price and volume effects associated with S&P addition reflect enhanced stock liquidity. The decrease in the bid/ask spread for nonoptioned stocks is attributed to informational efficiencies achieved via index arbitrage trading, and it is argued that this effect is mitigated for optioned stocks due to the pre‐existence of arbitrage trading between the option and the underlying stock.
An Examination of Mandatorily Convertible Preferred Stock
Authors: Huckins Nancy White
Published: March 2005

I investigate the determinants of the use of mandatorily convertible preferred stock and assess market reaction to its issue. The security is dividend enhanced and converted into common stock within four years. Issuers have high debt ratios, low interest coverage, and bankruptcy risk. Market response to the issue was neutral suggesting the preferred issue resolved the lemon problem associated with common stock. Firms' Z‐scores and abnormal returns are inversely related indicating the issues reduced financial distress. Market response was most positive for low risk firms with high cash flows.
Private Placement of Common Equity and Earnings Expectations
Authors: Goh Jeremy , Gombola Michael J. , Lee Hei Wai , Liu Feng‐Ying
Published: March 2005

We examine earnings forecast revisions by analysts subsequent to the announcement of private equity placements. Results show that analysts make significant upward revisions to their forecasts for current‐year earnings. Furthermore, these forecast revisions are significantly related to announcement‐period abnormal returns, but not to the risk changes accompanying the equity placement. These findings are consistent with the information hypothesis, which suggests that private equity placements convey favorable information about future earnings.
Nasdaq and The Chicago Stock Exchange: An Analysis of Multiple Market Trading
Authors: Van Ness Bonnie F. , Van Ness Robert A. , Hsieh Wen‐Liang
Published: March 2005

We analyze a set of 97 NASD‐listed securities that trade on both the Nasdaq and Chicago Stock Exchange (CHX) to determine if trading costs and price improvement differ between the two markets. We find that order execution costs, which we define by the traded spread and the signed effective half‐spread, are significantly lower on the CHX. This difference is consistent over trade types and for trades of at least 1,000 shares. Also, we find that trades occurring on the CHX receive more price improvement than do those occurring on Nasdaq.
Contagion Effects of Dividend Reduction or Omission Announcements in the Electric Utility Industry
Authors: Impson Michael
Published: March 2005

This study examines the contagion effects of dividend reduction or omission announcements in the electric utility industry. Using a series of ten electric utility dividend announcements covering the period 1979–1991, I analyze differences in contagion reactions across utilities. I find the strength of the contagion reaction is significantly related to utility size, average dividend yield, debt ratio, market‐to‐book ratio, cash flow, and Altman's Z‐score. There is also evidence of a flight to quality, including a preference for utilities operating in more favorable regulatory environments.
Informed and Uninformed Trading in an Electronic, Order‐Driven Environment
Authors: Brockman Paul , Chung Dennis Y.
Published: March 2005

The purpose of our study is to investigate the trading behavior of informed and uninformed investors in a screen‐based, order‐driven environment. As more and more exchanges conduct trading through electronic limit‐order books, it is increasingly important to analyze consequent trading behavior and its impact on the liquidity provision process. We examine one of the largest electronic, order‐driven markets in the world, the Stock Exchange of Hong Kong. Our findings show that the interaction of informed and uninformed traders plays a significant role in determining corporate liquidity.
Predictors of Bleeding Complications and Thrombocytopenia with the Use of Abciximab during Percutaneous Coronary Intervention
Authors: RAZAKJR OMAR ABDUL , TAN HUAY CHEEM , YIP WEI LUEN , LIM YEAN TENG
Published: March 2005

Abciximab (c7e3; ReoPro®; Centocor, Inc., Pennsylvania, USA), a Fab fragment of the chimeric human‐murine monoclonal antibody directed against platelet glycoprotein IIb/IIIa receptors, has been shown to reduce acute ischemic complications in patients undergoing percutaneous coronary interventions (PCI). However, its use has been associated with an increased incidence of bleeding events. The aim of this study is to examine the frequency of bleeding complications and to identify clinical variables associated with it in our patients.

We prospectively recorded incidence of bleeding complications in 344 consecutive patients who underwent PCI with adjunctive use of abciximab (Ab). Clinical predictors for patients who developed bleeding complications with Ab were compared with the nonbleeders.

Major bleeding occurred in six patients (1.7%) one of whom had pulmonary hemorrhage and one had intracranial hemorrhage. Minor bleeding occurred in 20 (5.8%) patients. Thrombocytopenia was seen in 13 (3.9%) patients of which four (1.2%) were mild, four (1.2%) were severe, and five (1.5%) were profound. Multivariate analyses showed that female gender and the “bail‐out” use of Ab were risk factors for bleeding complications. The rate of major bleeding complications and thrombocytopenia were low and comparable with published trials. Female patients and those who received Ab as a “bail‐out” were at higher risk of developing bleeding complications.
Crack‐Tip Structure in Soda–Lime–Silicate Glass
Authors: Guin Jean‐Pierre , Wiederhorn Sheldon M. , Fett Theo
Published: March 2005

The topology of crack tips in soda–lime–silicate glass was investigated using atomic force microscopy (AFM). Studies were conducted on cracks that were first propagated in water and then subjected to stress intensity factors either at or below the crack growth threshold. Exposure to loads at the crack growth threshold resulted in long delays to restart crack growth after increasing the stress intensity factor to higher values. After breaking the fracture specimen in two, the “upper” and “lower” fracture surfaces were mapped and compared using AFM. Fracture surfaces matched to an accuracy of better than 0.5 nm normal to the fracture plane and 5 nm within the fracture plane. Displacements between the upper and lower fracture surfaces that developed after a critical holding time were independent of distance from the crack tip, and increased with holding time. Despite the surface displacement, crack tips appeared to be sharp. Results are discussed in terms of a hydronium ion–alkali ion exchange along the crack surfaces and corrosion of the glass surface near the crack tip by hydroxyl ions.
Effects of Acetic Acid on the Crystallization Temperature of Sol–Gel‐Derived MgO Nano‐Powders and Thin Films
Authors: Kim Jin Young , Jung Hyun Suk , Hong Kug Sun
Published: March 2005

The influences of acetic acid addition to Mg‐methoxide on the stability of the precursor and the crystallization behavior of sol–gel‐derived MgO nano‐powders and thin films were investigated using X‐ray powder diffraction, transmission electron microscopy, Fourier‐transformed infrared spectroscopy, and thermogravimetry. The addition of acetic acid enhanced the stability of the alkoxide against precipitation. Moreover, during postheat treatment of the gel powders treated with acetic acid, a significantly lowered crystallization temperature (250°C) was observed as compared to the untreated counterpart (350°C). The low‐temperature crystallization of MgO, induced by the modification of Mg‐methoxide with acetic acid, was related to the decomposition of organics at a lower temperature. These results could be explained in terms of the decrease of the O–R bond strength depending on the increase in the alkyl group size. MgO thin films having a high degree of crystallinity were successfully obtained from the Mg‐methoxide treated with acetic acid at 300°C. The low‐temperature crystallization of sol–gel‐derived MgO thin films showed the feasibility for their application as a protective layer in alternative current plasma display panel cells.
Hot Corrosion Mechanism of Composite Alumina/Yttria‐Stabilized Zirconia Coating in Molten Sulfate–Vanadate Salt
Authors: Wu Nianqiang , Chen Zheng , Mao Scott X.
Published: March 2005

In order to improve the hot corrosion resistance of yttria‐stabilized zirconia (YSZ), an Al2O3 overlay has been deposited on the surface of YSZ by electron‐beam physical vapor deposition. Hot corrosion tests have been performed on the YSZ coatings with and without an Al2O3 overlay in the molten salt mixture (Na2SO4+0–15 wt% V2O5) at 950°C. The presence of V2O5 in the molten salt exacerbates degradation of both the monolithic YSZ coating and the composite YSZ/Al2O3 system. The formation of a low‐melting Na2O–V2O5–Al2O3 liquid phase is responsible for degradation of the Al2O3 overlay. The Al2O3 overlay acts as a barrier against the infiltration of the molten salt into the YSZ coating during exposure to the molten salt mixture with <5 wt% vanadate.
Comparison of Mechanical Properties of Silicon Nitrides with Controlled Porosities Produced by Different Fabrication Routes
Authors: Díaz Aranzazu , Hampshire Stuart , Yang Jian‐Feng , Ohji Tatsuki , Kanzaki Shuzo
Published: March 2005

Three different series of porous silicon nitride ceramics with volume fraction porosities in the range 0–0.5 were fabricated using different preparation routes: (i) partial sintering, (ii) the addition of fugitive inclusions, and (iii) partial hot pressing. The use of different sintering additives and firing conditions, depending on the preparation route, gives rise to different materials within a certain porosity range with variations in terms of microstructure and grain boundary phase. Mechanical properties, elastic moduli, and strength have been evaluated separately for each series of materials. Porosity dependences of Young's modulus, shear modulus, Poisson's ratio, and fracture strength have been assessed and a comparison of the different materials is made and discussed in relation to their microstructural features.
Stress–Strain Behavior During Compression of Polycrystalline La1−xCaxCoO3 Ceramics
Authors: Faaland Sonia , Grande Tor , Einarsrud Mari‐Ann , Vullum Per Erik , Holmestad Randi
Published: March 2005

Mechanical stress–strain behavior of LaCoO3, La0.8Ca0.2CoO3, and La0.7Ca0.3CoO3 was studied under compression at 25° and 300°C. A hysteresis in the stress–strain relationship due to reorientation of ferroelastic domains (deformation twins) was observed, and a remanent strain is measured after unloading. The cohersive stress, defined as the maximum in effective elastic compliance during first loading, increases with substitution of Ca for La and decreases with increasing temperature. Domain reorientation was confirmed by X‐ray diffraction of surfaces parallel and perpendicular to the loading direction. LaCoO3 can be regarded as a soft ferroelastic material while the 30% Ca‐substituted material is a hard ferroelastic. The hysteresis of the stress–strain relationship was clearly dependent on both composition and temperature.
Correlation between infant birth weight and mother's periodontal status
Authors: Marin Constanza , Segura‐Egea Juan J. , Martínez‐Sahuquillo Ángel , Bullón Pedro
Published: March 2005

Objectives: Recent studies have suggested that periodontal disease is a risk factor for low birth weight (LBW) with other multiple factors. A cross‐sectional study was undertaken to help further evaluate the proposed association between periodontal disease and infant birth weight.

Material and Methods: Caucasian pregnant women (n=152), aged 14–39 years, were enrolled while receiving prenatal care. Dental plaque, probing depth, bleeding on probing and clinical attachment level were recorded and three groups were made: healthy group (HG) (n=38), gingivitis group (GG) (n=71) and periodontitis group (PG) (n=43). At delivery, birth weight was recorded.

Results: Infant mean weight at delivery was 3293.9±508.1 g. The total incidence of preterm birth and LBW infants was 5.3% and 4.6%, respectively. The incidence of LBW infants was 3.5% in term gestations and 25% in preterm gestations. Mothers height correlated with infant birth weight (p=0.03). Significant difference in birth weight existed between mothers with <1.55 m (3229.23±462.57) and those with 1.65 m (3475.55±505.07). In the group of women >25 years old infant mean weight in HG was 3588.33±531.83, being lower in GG (3466.75±334.45) and even lower (3092.60±592.94) in PG (p=0.0198). Bleeding on probing was significantly greater in women with <2500 g infants (40.2±21.8%) compared with 2500–3499 g (18.6±15.1%) and 3500 g (17.1±16.1%) (p=0.009).

Conclusions: Periodontal disease in normal Caucasian pregnant women, older than 25 years, is statistically associated with a reduction in the infant birth weight. These data provide new evidence on the relationship between periodontal disease and birth weight.
Isolation of an Algal Morphogenesis Inducer from a Marine Bacterium
Authors: Matsuo Yoshihide , Imagawa Hiroshi , Nishizawa Mugio , Shizuri Yoshikazu
Published: March 2005

Ulva
and
Enteromorpha
are cosmopolitan and familiar marine algal genera. It is well known that these green macroalgae lose their natural morphology during short-term cultivation under aseptic conditions and during long-term cultivation in nutrient-added seawater and adopt an unusual form instead. These phenomena led to the belief that undefined morphogenetic factors that were indispensable to the foliaceous morphology of macroalgae exist throughout the oceans. We characterize a causative factor, named thallusin, isolated from an epiphytic marine bacterium. Thallusin induces normal germination and morphogenesis of green macroalgae.
Cathodic Stripping Voltammetry of 2-Thiouracils
Authors: Kasprzak Michał , Ciesielski Witold , Skrzypek Sławomira
Published: March 2005

Four 6-R-2-thiouracils (R = H, methyl, propyl, benzyl) were examined by differential pulse cathodic stripping voltammetry on mercury electrode. The research led to a very sensitive analytical method that allows their determination on nanomolar level. The detection limit of the 6-propyl derivative is as low as 1.0 × 10-9 mol dm-3. The procedure is very simple and utilizes only most common chemical reagents (such as acetate buffer). The buffer concentration plays an important role in the preconcentration stage, due to the adsorption processes accompanying electrode reactions. The new analytical method was tested with commercial samples of various antithyroid drugs.
The impact of introduced round gobies (Neogobius melanostomus) on phosphorus cycling in central Lake Erie
Authors: Bunnell David B , Johnson Timothy B , Knight Carey T
Published: March 2005

We used an individual-based bioenergetic model to simulate the phosphorus flux of the round goby (Neogobius melanostomus) population in central Lake Erie during 19952002. Estimates of round goby diet composition, growth rates, and population abundance were derived from field sampling. As an abundant introduced fish, we predicted that round gobies would influence phosphorus cycling both directly, through excretion, and indirectly, through consumption of dreissenid mussels, whose high mass-specific phosphorus excretion enhances recycling. In 1999, when age-1+ round gobies reached peak abundance near 350 million (2.4 kg·ha1), annual phosphorus excretion was estimated at 7 t (1.4 × 103 mg P·m2·day1). From an ecosystem perspective, however, round gobies excreted only 0.4% of the phosphorus needed by the benthic community for primary production. Indirectly, round gobies consumed <0.2% of dreissenid population biomass, indicating that round gobies did not reduce nutrient availability by consuming dreissenids. Compared with previous studies that have revealed introduced species to influence phosphorus cycling, round gobies likely did not attain a sufficiently high biomass density to influence phosphorus cycling in Lake Erie.
Vegetationenvironment relationships in zero-order basins in coastal Oregon
Authors: Sheridan Chris D , Spies Thomas A
Published: March 2005

Zero-order basins, where hillslope topography converges to form drainages, are common in steep, forested landscapes but we know little about their ecological structure. We used indirect gradient analysis to characterize gradients in plant species composition and cluster analysis to characterize groups of plant species associated with specific geomorphic areas. We sampled vegetation within 63 randomly selected zero-order basins in the southern Coast Range of Oregon and collected data on herb, shrub, and overstory tree cover, as well as environmental conditions. Zero-order basin overstories were similar in tree composition to both first-order riparian and upland plant assemblages, but were intermediate in tree density. Shrubs in zero-order basins included both species associated with dry upland conditions and species associated with riparian conditions. Results suggest that understory plant species composition in zero-order basins follows gradients in geomorphic and overstory conditions. Furthermore, it appears that zero-order basins have distinctive geomorphology and fluvial regimes. These distinctive features appear to support both plant species associated with riparian conditions and species associated with upland conditions. Zero-order basins represent the farthest upstream extension of riparian plant species into upland areas, increasing plant species diversity in steep, forested landscapes.
Impact of stand structure on surface fire ignition potential in Picea abies and Pinus sylvestris forests in southern Finland
Authors: Tanskanen Heidi , Venäläinen Ari , Puttonen Pasi , Granström Anders
Published: March 2005

Forest fire ignition potential was investigated in Picea abies (L.) Karst. (Norway spruce) and Pinus sylvestris L. (Scots pine) dominated stands of 0, 15, 3045, and 4060 years of age. A series of small-scale (<0.5 m2) ignition tests were carried out in experimental plots on 61 different days in June, July, and August. Ignition success percentages were analyzed in relation to stand structural properties, preclassified stand types, and the output of the Canadian Fire Weather Index system. In addition, the number of average stand-type-specific fire days was estimated based on weather data (JuneAugust) for southern Finland for the years 19912002. Factors in stand structure that significantly correlated with the ignition success percentage were canopy depth and leaf area index, the correlation coefficients being 0.575 (p < 0.005) and 0.582 (p < 0.005), respectively. In Pinus sylvestris dominated stands, ignition tests produced self-sustained surface fires in 32.0%, 24.0%, and 19.3% of cases in 0-, 15-, and 30- to 45-year age classes, respectively. In Picea abies dominated sites conditions were favorable for fire in 12.0% and 4.6% of trials in the 0- and 40- to 60-year age classes, respectively. The output of the FWI-system correlated well with the ignition success in June and July but poorly in August. Based on the 12-year time series analysis, there were on average per year 27, 18, and 14 potential fire days in 0-, 15-, and 30- to 45-year-old Pinus sylvestris stands, and 10 and 4 potential fire days in 0- and 40- to 60-year-old Picea abies stands, respectively. We concluded that the dominance of Picea abies or Pinus sylvestris and stand age appear to modify the ignition conditions significantly and should be used as threshold indicators in fire occurrence predictions.
Expression of TRPC4 channel protein that interacts with NHERF-2 in rat descending vasa recta
Authors: Lee-Kwon Whaseon , Wade James B. , Zhang Zhong , Pallone Thomas L. , Weinman Edward J.
Published: March 2005

The PDZ domain adaptor protein Na+/H+ exchanger regulatory factor (NHERF)-2 is expressed in renal medullary descending vasa recta (DVR), although its function has not been defined. Transient receptor potential channels (TRPC) TRPC4 and TRPC5, nonselective cation channels that transport Ca2+, were recently demonstrated to complex with the NHERF proteins. We investigated whether TRPC4 and/or TRPC5 are associated with NHERF-2 in DVR. RT-PCR revealed mRNA for TRPC4 and NHERF-2, but not for TRPC5 or NHERF-1, in microdissected DVR. Immunohistochemical studies demonstrated expression of TRPC4 and NHERF-2 proteins in both the endothelial cells and pericytes. These proteins colocalized in some cells of the DVR. TRPC4 coimmunoprecipitated with NHERF-2 from renal medullary lysates, and NHERF-2 coimmunoprecipitated with TRPC4. TRPC5 was not detected in DVR with the use of immunohistochemistry or in NHERF-2 immunoprecipitates. We conclude that DVR pericytes and endothelia coexpress TRPC4 and NHERF-2 mRNA and protein and that these proteins colocalize and coimmunoprecipitate, indicating a possible physical association. These findings suggest that TRPC4 and NHERF-2 may play a role in interactions related to Ca2+ signaling.
Regulatory effects of estrogen on acute lung inflammation in mice
Authors: Speyer Cecilia L. , Rancilio Nicholas J. , McClintock Shannon D. , Crawford Jeffrey D. , Gao Hongwei , Sarma J. Vidya , Ward Peter A.
Published: March 2005

The role of estrogen in the regulation of the inflammatory response is not well defined. In this study, we investigated the effects of ovarian hormones on the acute inflammatory response in mouse lungs. Acute lung injury was induced by intratracheal instillation of bacterial lipopolysaccharide (LPS) in male, female, and ovariectomized (OVX) mice. End points of injury were polymorphonuclear neutrophil (PMN) content in bronchoalveolar lavage (BAL) fluids, myeloperoxidase activity in whole lung, and leak of albumin into the lung. After intratracheal instillation of LPS, all end points of injury were substantially increased in male and OVX mice compared with the female mice with intact ovaries. BAL fluids of all mice showed similar levels of chemokines (macrophage inflammatory protein MIP-2, KC, and monocyte chemoattractant proteins MCP-1 and MCP-3) and TNF-α, but enhanced levels of IL-1β were found in OVX and male mice. Serum levels of IL-6 and ICAM-1 levels in lung homogenates from OVX and male mice, compared with those in female mice with intact ovaries, were also enhanced after instillation of LPS. Albumin and PMN content in LPS-injured lungs were reduced to levels found in female mice after administration of estradiol in OVX mice and corresponded to reduced IL-1β, IL-6, and ICAM-1 levels. These data suggest that estrogen suppresses lung inflammatory responses in mice through an effect on vascular cell adhesion molecules and proinflammatory mediators.