bluuebunny/crossref_metadata_2025 huggingface dataset:
Using a Functional Model to Develop a Mathematical Formula
Authors: Otto Charlotte A. , Everett Susan A. , Luera Gail R.
Published: March 2010

The unifying theme of models was incorporated into a required Science Capstone course for pre‐service elementary teachers based on national standards in science and mathematics. A model of a teeter‐totter was selectedfor use as an example of a functional model for gathering data as well as a visual model of a mathematical equation for developing the mathematical relationship for a Class 1 lever, M1D1=M1D1. In this study, 20 student groups (n=72) collected data using the model in an inquiry‐based activity. All groups developed the qualitative relationship, 13 groups developed a correct mathematical formula, 6 groups developed one‐half of the relationship (X = mass × distance), and 1 group attempted to develop a procedural relationship. The pre‐service elementary teachers used a variety of model types in the activity including visual/pictorial, functional/physical and mathematical‐both graphs and formulas. The use of the teeter‐totter model as a visual and functional model of a mathematical formula was a factor in developing the mathematical relationship.
Using Metaphors to Unpack Student Beliefs About Mathematics
Authors: Schinck Amélie G. , Neale Henry W. , Pugalee David K. , Cifarelli Victor V.
Published: March 2010

This paper reports on an exploratory study of the mathematical beliefs of a group of ninth and tenth grade students at a large, college preparatory, private school in the Southeastern United States. These beliefs were revealed using contemporary metaphor theory. A thematic analysis of the students' metaphors for mathematics indicated that students had well developed and complex views about mathematics including math as: an Interconnected Structure, a Hierarchical Structure, a Journey of Discovery, an Uncertain Journey, and a Tool. Another prevalent theme revealed by the metaphors was that students believe perseverance is needed for success in mathematics. The data also suggest an impact of gender and tracking on students beliefs about mathematics. Creating metaphors for mathematics provided a catalyst for student reflection, class discussion, and qualitative data, which could aid program evaluation. Several areas for future research were identified through this exploratory study.
Learning and Assessing Mathematics through Reading and Writing
Authors: Bossé Michael J. , Faulconer Johna
Published: March 2010

Students learn mathematics more effectively and more deeply when reading and writing is directed at learning mathematics. Although reading and writing in mathematics may necessitate more skills and practice to master, the mathematical learning derived from reading and writing mathematics far outweighs the burden it places on teachers and students. This paper explores the vital role of purposeful reading and writing in the mathematics classroom and outlines some techniques to promote successful integration of reading and writing in mathematics.
The “Problem” of Experience in Mathematics Teaching
Authors: Superfine Alison Castro
Published: March 2010

Prior research has established that teachers' use of curriculum materials is affected by a range of factors, such as teachers' conceptions of mathematics teaching, and the nature and extent of their teaching experience. What is less clear, and far less examined, in prior research is the role that the teacher guide (TG) may play in mediating the influence of these and other factors on teachers' decisions and actions. Accordingly, this study examines how two 6th grade teachers use the TG from Connected Mathematics Project as a resource in making planning and enactment decisions, and factors associated with patterns of TG use. Through cross‐case analysis, the author found that these teachers seemed to draw largely from their previous experiences and their own conceptions of mathematics teaching and learning when making planning and enactment decisions related to mathematical tasks, and not particularly from the TG. For example, when faced with certain planning and instructional challenges, such as students struggling with the content, teachers tended to rely on their particular conceptions of mathematics teaching to address these challenges. Despite the fact that the TG provided suggestions for teachers as to how address such challenges, it was not extensively used as a resource by the teachers in this study in their planning and enactment of lessons.
Model‐Based Inquiry and School Science: Creating Connections
Authors: Passmore Cynthia , Stewart Jim , Cartier Jennifer
Published: March 2010

Much has been made in recent years of inquiry approaches to science education and the promise of such instruction to alleviate some of the ills of science education, yet in some ways this construct is still unclear to many in the field. In this paper we explore one view of inquiry in science that is based on the development, use, assessment, and revision of models and related explanations. Because modeling plays a central role in scientific inquiry it should be a prominent feature of students’ science education. We present a framework based on this view that can serve as a guide to curriculum development and instructional decision‐making with the goal of creating classroom environments that mirror important aspects of scientific practice. Specifically, the framework allows us to emphasize that scientists: engage in inquiry other than controlled experiments, use existing models in their inquiries, engage in inquiry that leads to revised models, use models to construct explanations, use models to unify their understanding, and engage in argumentation. Here, we discuss how these practices can be incorporated into science classrooms and illustrate that discussion with examples from our research classrooms.
Preparing Pre‐Service Teachers to Teach Mathematics in Inclusive Classrooms: A Three‐Year Case Study
Authors: Burton Dolores , Pace Darra
Published: March 2010

Federal and state regulations mandating inclusion of students with disabilities in general education classes have made it essential to create pathways for pre‐service teachers to develop skills to teach content to diverse groups of students. The study uses a framework suggested by the relationship between teacher attitude and teacher behavior (Fullan, 1982), teacher beliefs and practice, and self‐efficacy and behavioral change (Bandura, 1977). The purpose of the study was to examine changes, if any, in three cohorts of general education teacher candidates' (n=13, n=8, n=5) attitudes toward teaching mathematics to students with disabilities after participating in focused instructional experiences which provided both information and vicarious positive teaching activities in special education. Data collected included pretest and posttest scores for each of the three cohorts and journal entries. Little or no change in attitude towards students with disabilities and mathematics, and efficacy to teach students with disabilities was observed for the year one and year two cohorts. In the third year the modules were combined with a structured field experience. The data collected from the third year cohort suggested a positive trend in attitude as measured by the survey data and field experience journal data. Future study with larger samples is needed.
Mix It Up: Teachers' Beliefs on Mixing Mathematics and Science
Authors: Offer Joey , Mireles Selina Vasquez
Published: March 2010

This paper defines correlation, describes the Mix It Up program, discusses the teachers' beliefs about the value of correlating mathematics and science prior to program participation, and identifies problems teachers associated with correlation before and during the program. Teachers' beliefs about the value of correlation and about the problems associated with correlation are based on results from both quantitative and qualitative methods used to evaluate the program. Results indicate that teachers believe correlating mathematics and science strengthens students' content knowledge in mathematics and science, bridges the gap between mathematics and science, enhances motivation, and increases students' flexibility in problem solving. Additionally, the areas identified by teachers to be most problematic were time, planning for instruction as a team, and exposure to correlation in the past. The most important finding from the program evaluation indicates that although teachers did not identify content knowledge weaknesses before participating in the program, they did recognize gaps in their own content knowledge during program participation, and more importantly they made connections among these gaps, classroom instruction, and their own students' performance in mathematics and science.
Undergraduate Engineering Majors' Beliefs About Mathematics
Authors: Berkaliev Zaur , Kloosterman Peter
Published: March 2010

This study examined the mathematics beliefs of college students in 10 undergraduate mathematics classes at a large engineering school in the Midwest. The beliefs of 254 engineering majors were measured by the Indiana Mathematics Belief Scales and compared to the beliefs of elementary education majors and remedial college mathematics students obtained from earlier studies using the same instrument. The results were interpreted in terms of the students' daily attitudes towards their mathematics classes and corresponding academic and demographic parameters. The study showed that in many respects, the beliefs of the engineering majors were not that different from the other populations. The correlations among beliefs for the engineering group tended to be higher although there were relatively few significant correlations between belief and background variables. Attitude data were collected across a full semester for the engineering majors. The relatively modest day‐to‐day variation in those attitudes suggests that they are based on deeply seated beliefs.
A Preservice Secondary Teacher's Moves to Protect Her View of Herself as a Mathematics Expert
Authors: Plummer Julie Stafford , Peterson Blake E.
Published: March 2010

This paper discusses the experience of a preservice secondary mathematics teacher during lesson study. Although the preservice teacher was a strong undergraduate mathematics student, she used compensation “moves” to deflect attention away from her insecurities about her conceptual understanding of secondary mathematics. She feared being labeled as “dumb” and redirected conversations in order to protect her identity as a knower of mathematics. This paper investigates the culture in which preservice teachers develop confidence in their personal mathematics knowledge and how that confidence may influence behavior.
Turkish Prospective Chemistry Teachers' Alternative Conceptions about Acids and Bases
Authors: Boz Yezdan
Published: March 2010

The purpose of this study was to obtain prospective chemistry teachers' conceptions about acids and bases concepts. Thirty‐eight prospective chemistry teachers were the participants. Data were collected by means of an open‐ended questionnaire and semi‐structured interviews. Analysis of data indicated that most prospective teachers did not have difficulties about macroscopic properties of acids and bases. However, despite chemistry instruction, most of the prospective teachers were found to have problems in understanding the neutralization concept, the distinction between strength and concentration of acids and linking the acids and bases topic to daily life. These findings have some implications for teacher education programs.
Endothelial lipase and reverse cholesterol transport in type 2 diabetes mellitus
Authors: Shiu Sammy WM , Zhou Huali , Wong Ying , Tan Kathryn CB
Published: March 2010

Aims/Introduction:  Endothelial lipase (EL) plays an important role in high‐density lipoprotein (HDL) metabolism and experimental data suggest that EL might be proatherogenic. We have investigated whether serum EL concentration is associated with changes in serum capacity to induce cholesterol efflux and arterial stiffness in type 2 diabetes.

Materials and Methods:  Serum EL was assayed by ELISA in 172 diabetic patients and 175 controls. The ability of serum to induce cholesterol efflux was measured using a cell culture system and arterial stiffness was determined by measuring pulse wave velocity (PWV) between carotid and femoral arteries.

Results:  Diabetic patients had significantly higher C‐reactive protein (CRP) and EL (27.7 ± 16.6 ng/mL vs 24.0 ± 11.3, P < 0.05). Cholesterol efflux to serum mediated through scavenger receptor class B type I was impaired (15.1 ± 2.5%vs 16.7 ± 3.1, respectively, P < 0.01). In controls, serum EL correlated with cholesterol efflux to serum (r = −0.16, P = 0.025), but only a trend was seen in the diabetic patients. Linear regression showed that in controls, HDL, serum EL and waist circumference were major independent determinants of cholesterol efflux; whereas in the diabetic cohort, the major independent determinants of cholesterol efflux were HDL, CRP and age. PWV was increased in the diabetic patients (P < 0.01), but no association between serum EL and PWV was seen in either groups.

Conclusions:  Serum EL was increased in diabetic patients, but impaired serum capacity to induce cholesterol efflux in these patients was mainly related to low HDL and subclinical inflammation. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00016.x, 2010)
Corporate Cash Holdings and Tax‐induced Debt Financing
Authors: Jung Kooyul , Kim Byungmo
Published: March 2010

Stockpiling of liquid assets in cash decreases the possibility of a firm's falling into financial distress and becoming technically insolvent. Such stockpiling provides incentives for firms to increase their leverage because cash holdings decrease potential financial distress costs and increase target debt‐equity ratios. This paper examines whether firms' excessive cash holdings enhance an explanatory power of the marginal tax rate for the change in leverage. The results show that high‐taxed firms with excess cash are more likely to increase their leverage. The increase in leverage is not to discipline the entrenched managers' discretionary use of free cash, and the excess cash is not simply for planned future investments either. We also find that the results still hold even when the financial crisis periods are excluded and that the debt financing behavior changes with the level of statutory tax rate. These findings provide evidence that firms with sufficient cash are more likely to take advantage of interest tax shields.
Studies on Information Asymmetry, Price Manipulation and Investor Performances*
Authors: Yoo Jin
Published: March 2010

In this paper, we examine optimal investment strategies of informed traders in an equity market, where well informed and not so well informed traders as well as noise traders coexist. Naturally, less informed traders follow more informed counterparts because of informational advantage. On the other hand, more informed investors can take advantage of less informed investors' trust by manipulating prices. Often, by inflating or deflating the equity prices, more informed traders make greater profits than less informed traders do. Over time, less informed traders become aware of the others' strategy, thereby a long‐term equilibrium is to be attained, in which the more informed mixes his sincere and cheating strategy, and the less informed mixes his trust and distrust strategy. This model can be especially useful in understanding emerging markets, where foreign investors, local institutions, and local individuals are often characterized as more informed, less informed, and noise traders, respectively.
Risk Measurement and Investment Myopia in Hedge Fund Management*
Authors: Li Xun , Wu Zhenyu
Published: March 2010

Lo (2001) surveys the literature on risk management for hedge funds, and recommends a dynamic and transparent risk measurement for the evolutionary hedge fund industry by citing Albert Einstein's comments. This study is to explore the feasibility and advantages of adopting a dynamic absolute‐deviation risk measurement in hedge fund management. It does not only provide an optimal asset allocation strategy both analytically and numerically in a dynamic mean‐absolute deviation (DMAD) setting for hedge fund managers, but also contributes to mitigation of potential investment myopia problems in their risk‐taking behaviors. It sheds light on risk management and investor‐fund manager agency conflicts in the hedge fund industry and adds to the literature on portfolio selection and optimal asset allocation.
CEO Power and Firm Performance: A Test of the Life‐Cycle Theory*
Authors: Harjoto Maretno A. , Jo Hoje
Published: March 2010

We examine the effects of corporate governance and monitoring mechanisms on the choice of board leadership structure and the value and performance of a firm according to the firm's life‐cycle changes. Employing a large and extensive sample during the 1995–2005 period, we find that the board leadership choice is associated with governance characteristics including board independence, managerial entrenchment, and CEO abilities measured by CEO age and CEO tenure after controlling for various firm characteristics. In addition, after correcting for the endogenous treatment effect, our results show that while CEO dualities‐i.e., CEO‐chair of the board or CEO‐nomination committee member — or CEO pluralities‐i.e., CEO‐chair of the board, and a chair or a member of the nomination committee‐positively influences firm value and performance in firm's early stage, CEO duality or CEO pluralities adversely influences firm value and operating performance in firm's late stage. These results are supportive of the life‐cycle theory, suggesting that CEO power concentration is beneficial in firms' early stage, but harmful in firm's late stage at which firms require check‐and‐balance as opposed to dictatorship. In addition, the impact of external monitoring by institutional ownership on firm value and performance is more effective than those of independent board and blockholders' ownership while the impact of Sarbane‐Oxley Act on firm performance is not significant.
Foreign Bond Investment and the Yield Curve*
Authors: Suh Sangwon
Published: March 2010

Market participants have argued that the yield curve in the Korean bond market has been increasingly flattened since 2007 caused partly by foreign investors' rapidly growing investment in Korean bond market, motivated to take advantage of market imperfections seeking riskless profit making opportunities. To analyze how much foreign bond investments have affected the bond yields in Korea, in this paper I utilize a stylized affine term structure model that has an observable factor related with foreign bond investments as well as latent factors. I find supportive evidence for the argument by market participants that investment by foreigners has been an important factor behind the flattening of the yield curve since 2007. Taking out the effects of foreign bond investment on the yields, I observe much a weakened yield flattening phenomenon.
The Impact of Trade Characteristics on Stock Return Volatility: Evidence from the Australian Stock Exchange*
Authors: Frino Alex , Segara Reuben , Zheng Hui
Published: March 2010

This study examines the impact of trade characteristics on stock return volatility. Using a sample of transaction data from the Australian Stock Exchange, the trading frequency of medium sized trades is found to have the greatest impact on stock return volatility. The result lends support to the stealth trading hypothesis (Barclay and Warner, 1993). After controlling for trading frequency, the average trade size is found to have little explanatory power on price volatility. Stock return volatility is more sensitive to buyer‐initiated trades than seller‐initiated trades, especially so for buyer‐initiated medium sized trades. This finding is consistent with the assertion that information effects are stronger for buys than for sells (Chan and Lakonishok, 1993).
Negative Momentum Profit in Korea and its Sources*
Authors: Chae Joon , Eom Yunsung
Published: March 2010

To analyze the negative momentum profit in Korea, we further divide the decomposition of Lo and MacKinlay (1990) into winners' and losers' auto‐ and cross‐serial covariances. We find that the negative autocovariance and the positive cross‐serial covariance in Lo and MacKinlay's decomposition are asymmetric between winners and losers. The negative autocovariance is mainly from losers and the positive cross‐serial covariance mainly between past winners and current losers. By investigating time‐series characteristics of auto‐(cross‐serial) covariances, we cannot observe any systematic change of auto‐(cross‐serial) covariances in the momentum period. Based upon the evidence in this paper, we argue that positive cross‐serial covariance between past winners and current losers seems to be an important driving force behind the negative momentum profit in Korea. Therefore, investors' underreaction to market‐wide information would be plausible explanation of the negative momentum profit.
The Impact of Day‐Trading on Volatility and Liquidity*
Authors: Chung Jay M. , Choe Hyuk , Kho Bong‐Chan
Published: March 2010

We examine day‐trading activities for 540 stocks traded on the Korea Stock Exchange using transactions data for the period from 1999 to 2000. Our cross‐sectional analysis reveals that day‐traders prefer lower‐priced, more liquid, and more volatile stocks. By estimating various bivariate VAR models using minute‐by‐minute data, we find that greater day‐trading activity leads to greater return volatility and that the impact of a day‐trading shock dissipates gradually within an hour. Past return volatility also positively affects future day‐trading activity. We also find that past day‐trading activity negatively affects bid‐ask spreads, and past bid‐ask spreads negatively affect future day‐trading activity. Finally, we find that day‐traders use short‐term contrarian strategies and their order imbalance affects future returns positively. This result is consistent with a cyclical behavior of day‐traders who concentrate their buy or sell trades at the bottom or peak of the short‐term price cycles, respectively.
Stress Testing of Financial Industries: A Simple New Approach to Joint Stress Testing of Korean Banking, Securities, and Non‐Life Insurance Industries*
Authors: Chang Kook‐Hyun , Kim Myung‐Jig
Published: March 2010

This paper proposes a simple joint stress testing model useful in studying the effects of specific stress scenarios on a financial sector. In doing so, we adopt the principal component analysis (PCA) as a main device to interpret various financial information contained in figures and numbers on a financial company. We repeat the principal component analysis across different levels from individual company to a financial industry, and eventually to a financial sector as a whole to derive a financial sector risk index. We then link the sector risk index with stress macro variables, which constitute a much simpler task than devising individual models for each financial components. Once a relationship is established, a joint stress test is conducted by repeating PCA conversely. As a sample of stress scenario in the paper, we use the case of the 2003 credit card distress. We find that securities industry is more sensitive to market stresses than two other industries‐bank and insurance‐and that financial institutions in such a stress‐sensitive industry are, consequently, more affected by the stresses than those in other industries. Despite the simplicity of the proposed model, this model is expected to provide substantial information, particularly for financial supervisors without having to build a complicated joint stress testing model.
Financial Reporting by Business Groups and the Market's Ex ante Valuation of Tunneling: Evidence from Korean Chaebols*
Authors: Kim Kwon‐Jung
Published: March 2010

This study examines how the Korean stock market reacts to the release of group‐level financial statements by Korean business groups (chaebols). I find that chaebol firms that perform relatively well (measured by ROE) within their group but whose controlling shareholders have low levels of cash‐flow rights experience negative price reactions particularly when their group ROE is low. In contrast, chaebol firms whose controlling shareholders have high levels of cash‐flow rights do not experience negative price reactions even when their group ROE is negative. These findings are consistent with the market anticipating that “tunneling” will occur in low‐cash‐flow‐right firms, but not in high‐cash‐flow‐right firms, to provide support to poorly performing firms. To corroborate these results, I also examine whether tunneling actually occurs within one year after the group‐earnings announcements. I find that in many cases, resources of low‐cash‐flow‐right firms with relatively good performance are actually transferred to poorly performing firms (mostly, unlisted firms) through purchasing new equity of poorly performing firms. Moreover, the magnitude of negative price reactions at the time of group‐earnings announcements is significantly related to the magnitude of resources transferred to poorly performing firms.
An Importance Sampling Method to Evaluate Value‐at‐Risk for Assets with Jump Risk*
Authors: Wang Ren‐Her , Lin Shih‐Kuei , Fuh Cheng‐Der
Published: March 2010

Risk management is an important issue when there is a catastrophic event that affects asset price in the market such as a sub‐prime financial crisis or other financial crisis. By adding a jump term in the geometric Brownian motion, the jump diffusion model can be used to describe abnormal changes in asset prices when there is a serious event in the market. In this paper, we propose an importance sampling algorithm to compute the Value‐at‐Risk for linear and nonlinear assets under a multi‐variate jump diffusion model. To be more precise, an efficient computational procedure is developed for estimating the portfolio loss probability for linear and nonlinear assets with jump risks. And the titling measure can be separated for the diffusion and the jump part under the assumption of independence. The simulation results show that the efficiency of importance sampling improves over the naive Monte Carlo simulation from 7 times to 285 times under various situations. We also show the robustness of the importance sampling algorithm by comparing it with the EVT‐Copula method proposed by Oh and Moon (2006).
Do Controlling Shareholders Manage the Timing of Information Disclosure When Making a Stock Gift?*
Authors: Jung Woon‐Oh , Park Sung‐Ook
Published: March 2010

In Korea, controlling shareholders in general tend to transfer their shares to their family members or related parties. In this paper, we investigate whether Korean controlling shareholders attempt to influence stock prices by managing the timing of information disclosures when they transfer stocks to related parties as gifts. Because gift taxes are levied based on the average market value of the stock transferred for a certain period known as the valuation period, controlling shareholders may have incentives to depress the stock prices in this period in order to reduce the gift tax. We make a specific conjecture that controlling shareholders may wish to time the disclosure of good news and bad news so that the latter (the former) is released during (outside of) the valuation period for the stock to be transferred. To test this hypothesis we examine the disclosure timing of good and bad news for a sample of 118 gift transactions by 83 firms over the period of 2000–2004. We find that during the valuation period (i.e., the 4‐month period extending over the 2 months before and after the gift transaction) the frequency of good news was considerably lower than in other periods, whereas the frequency of bad news during the valuation period was substantially higher. This result supports the hypothesis that controlling shareholders may delay good news and bring forward bad news in an attempt to influence stock prices during the valuation period. Despite the attempts by controlling shareholders to keep stock prices depressed in the valuation period, we also find that the prices tend to increase after the gift announcement date. We provide some of the potential explanations for the upward price movement subsequent to gift transactions.
Pricing Weather Derivatives using a Predicting Power Time Series Process*
Authors: Chang Chuang‐Chang , Lin Jun‐Biao , Shen Wen‐Min
Published: March 2010

This paper extended the Cao‐Wei (2004, JFM) model to construct a theoretical model for pricing weather derivatives in two significant ways. One adopted a time series model developed by Campbell and Diebold (2005, JASA) to describe the dynamics of temperature. The advantage of using Campbell and Diebold's time series model to describe the temperature dynamics is that it can not only take the conditional mean of temperature coming from trend, seasonal, and cyclical components but also allow for the conditional variance dynamics. The other purpose of this paper is to use an extended power utility function, instead of Cao and Wei's constant proportional risk aversion (CPRA) utility function. The extended power utility function could exhibit decreasing, constant, and increasing relative risk aversion. Eventually, we find that the prices of weather derivatives can be determined by weather conditions, discount factors, and forward premiums. Additionally, these sources have close relations with some risk aversion parameters. Furthermore, the results are consistent with Cao and Wei's condition under some specific parameter assumptions.
The Influence of Corporate Governance on Corporate Performance and Value after Changing the CEO: Evidence from Taiwan*
Authors: Huang Hsu‐Huei , Chan Min‐Lee
Published: March 2010

Can corporate performance be improved by changing the CEO? The answer to this question may vary from country to country or from firm to firm. This study proposes that, generally speaking, firms in countries with a better corporate governance environment or firms with better governing mechanisms are more likely to see improvements in performance after a change in their CEOs than those without this environment or these mechanisms. To test this corporate governance hypothesis, we compared corporate performance and value measures of 155 listed companies in Taiwan that had their CEOs replaced between 1996 and 2002. At the national level, we found that in Taiwan corporate performance did not generally improve by merely replacing the CEO. At the firm level, companies with better corporate governance in terms of ownership structure and board structure were found to have better performance and higher corporate value after changing the CEO, and they were also found to have a better net improvement in performance.
Nonlinear Dynamic Relations Between Equity Return and Equity Fund Flow: Korean Market Empirical Evidence*
Authors: Kim Sei‐Wan , Kim Youngmin
Published: March 2010

This research studies the dynamic relationship between equity returns and equity fund flows by incorporating nonlinear properties of the two variables. Nonlinear estimation based on a smooth transition autoregressive model reveals results different from those previously reported based on a linear relationship. Our empirical results find that there is significant mutual Granger causality between equity returns and equity fund flows. In addition, by introducing the dividend yield effect, significant Granger causality is also found between the three variables. This can be interpreted as meaning that demand for equities is downward sloping for both the price pressure effect and the information effect. Relatively fast regime switching and dynamic instability show that stock investment through equity funds is mostly short‐horizon‐oriented investment.
Association Between Accounting Conservatism and Analysts’ Forecast Inefficiency*
Authors: Pae Jinhan , Thornton Daniel B.
Published: March 2010

We find that analysts’ earnings forecasts do not fully impound the implications of accounting conservatism. Forecast optimism is negatively associated with the magnitude of beginning‐of‐year balance sheet reserves (BSR), which are associated with conservative accounting in prior years. However, this result vanishes once we allow for the negative association, documented in several prior studies, between BSR and Basu’s asymmetric timeliness measure of conservatism [Journal of Accounting and Economics 24 (1997) 3]. After controlling for this association, we find that forecasters’ under‐reaction to bad versus good news is negatively associated with the magnitude of BSR. We obtain similar results after allowing for the positive association between asymmetric timeliness and Khan and Watts’ C_Score [Journal of Accounting and Economics 48 (2009) 132]. Therefore, our results are consistent with a subtle form of inefficiency of forecasts with respect to accounting conservatism; that is, analysts do not fully appreciate that the earnings of companies with lower BSR or higher C_Scores are likely to be both: (i) lower relative to forecast; and (ii) more asymmetrically timely than the earnings of companies exhibiting higher BSR or lower C_Scores.
Optimal Design of a Hybrid-Driven Servo Press and Experimental Verification
Authors: Tso Pei-Lum
Published: March 2010

This paper focuses on a hybrid-driven servo press, which uses not only a servomotor but also a regular ac motor with a flywheel. A PC-based control system is developed based on both feedback and iterative learning control theories on a prototype. The stamping performance, improved forming ability, and energy saving merits have been verified by the experiment. The results show that the advantages of the hybrid-driven servo press have been validated, such as its energy saving features, flexible punch speeds, and adjustable strokes, for any kind of stamping operations.
Multicategory Design of Bundled Products for Retail Channels Under Uncertainty and Competition
Authors: Williams N. A. , Azarm S. , Kannan P. K.
Published: March 2010

One prevalent approach to increase both retailer and manufacturer revenues are to improve the attractiveness of a product offering by bundling related product categories together for one price. To be most effective, bundled products should be developed with an integrated design approach that seeks to achieve utility for the end customer. We propose a bundled product design approach that endogenizes demand dependencies between the product categories and thus determines the impact of the bundle and cross-category competition on proposed engineering designs. Additionally, the approach simultaneously considers uncertainty in engineering design, competing manufacturer product attributes, and customer preferences to ensure acceptable product profitability and market share under interval uncertainty. We find after optimizing manufacturer profit and market share that considering demand dependencies can lead to optimal bundle and individual product designs that increase profits for both retailer and manufacturer.
A Hierarchical Statistical Sensitivity Analysis Method for Multilevel Systems With Shared Variables
Authors: Liu Yu , Yin Xiaolei , Arendt Paul , Chen Wei , Huang Hong-Zhong
Published: March 2010

Statistical sensitivity analysis (SSA) is an effective methodology to examine the impact of variations in model inputs on the variations in model outputs at either a prior or posterior design stage. A hierarchical statistical sensitivity analysis (HSSA) method has been proposed in literature to incorporate SSA in designing complex engineering systems with a hierarchical structure. However, the original HSSA method only deals with hierarchical systems with independent subsystems. For engineering systems with dependent subsystem responses and shared variables, an extended HSSA method with shared variables (named HSSA-SV) is developed in this work. A top-down strategy, the same as in the original HSSA method, is employed to direct SSA from the top level to lower levels. To overcome the limitation of the original HSSA method, the concept of a subset SSA is utilized to group a set of dependent responses from the lower level submodels in the upper level SSA and the covariance of dependent responses is decomposed into the contributions from individual shared variables. An extended aggregation formulation is developed to integrate local submodel SSA results to estimate the global impact of lower level inputs on the top level response. The effectiveness of the proposed HSSA-SV method is illustrated via a mathematical example and a multiscale design problem.
High-quality molecular-beam-epitaxy-grown Ga2O3(Gd2O3) on Ge (100): Electrical and chemical characterizations
Authors: Chu R. L. , Lin T. D. , Chu L. K. , Huang M. L. , Chang C. C. , Hong M. , Lin C. A. , Kwo J.
Published: March 2010

High-κ dielectric Ga2O3(Gd2O3) (GGO) has been deposited on Ge (100) at room temperature using molecular beam epitaxy. In situ angular-resolved x-ray photoelectron spectroscopy on the GGO/Ge after gate dielectric deposition and 500°C postdeposition annealing has exhibited negligible Ge interdiffusion, thus revealing high thermal stability of the heterostructure. The CF4-plasma treatment on the passivated GGO/Ge has greatly improved the capacitance-voltage characteristics of the metal-oxide-semiconductor capacitors, besides the very low gate leakage current density of 3.2×10−9A∕cm2 at a flat-band voltage +1V. These excellent interfacial characteristics have been achieved without employing any intentional passivation layers.
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ultrahigh-sensitivity image sensor with active-matrix high-efficiency electron emission device
Authors: Nakada Tomonari , Sato Takanobu , Matsuba Yohei , Sakemura Kazuto , Okuda Yoshiyuki , Negishi Nobuyasu , Watanabe Atsushi , Yoshikawa Takamasa , Ogasawara Kiyohide , Nanba Masakazu , Tanioka Kenkichi , Egami Norifumi , Kobayashi Akira , Koshida Nobuyoshi
Published: March 2010

A 640×480pixel image sensor has been developed for low light imaging with a practical resolution. This image sensor combined an active-matrix high-efficiency electron emission device (HEED) with a high-gain avalanche rushing amorphous photoconductor (HARP) target. To meet the requirement for a scaling of the imaging size, we developed a 2∕3in. image sensor based on an active-matrix HEED with 13.75×13.75μm2pixels. The highly emissive property of 3.8μA∕pixel was comparable to that obtained previously from a 1in. device. The possible effect of the pixel size scaling on the image-pickup sensitivity was compensated by a significant increase in the emission current density. The technological potential of the HEED-HARP image sensing has been further enhanced toward practical use.
High-optical-quality nanosphere lithographically formed InGaAs quantum dots using molecular beam epitaxy assisted GaAs mass transport and overgrowth
Authors: Qian Xifeng , Vangala Shivashankar , Wasserman Daniel , Goodhue William D.
Published: March 2010

Optically active, highly uniform, cylindrical InGaAs quantum dot (QD) arrays have been fabricated using nanosphere lithography combined with Bromine ion-beam-assisted etching and molecular beam epitaxy (MBE)-assisted GaAs mass transport. Previously fabricated QD nanopillar arrays showed significant degradation of optical properties due to the etch damage. Here, a novel mass transport process in a Riber 3200 was performed to encapsulate the lithographically defined InGaAs disk QDs in a GaAs matrix, resulting in the passivation of the etch-damaged QD sidewall layer. Photoluminescence emission intensity following the mass transport process increased by a magnitude of 4–10 as compared to that from unprocessed nanopillar sample. In addition, a PL peak energy redshift was observed after mass transport, presumably due to the decrease in the lateral barrier potential from vacuum to GaAs, as well as the elimination of the depletion layer. Furthermore, the mass transport process in the high vacuum MBE environment enables GaAs overgrowth with few defects and dislocations following mass transport for surface planarization. PL emission intensity increased by an additional factor of 4 following GaAs overgrowth, bringing the QD intensity to 12 of that of the original single quantum well. Thus, the potential of the MBE-assisted mass transport process has been demonstrated to fabricate high optical quality InGaAs quantum dots encapsulated in a GaAs matrix for device applications.
Molecular beam epitaxy as a method for the growth of freestanding zinc-blende (cubic) GaN layers and substrates
Authors: Novikov S. V. , Zainal N. , Akimov A. V. , Staddon C. R. , Kent A. J. , Foxon C. T.
Published: March 2010

The authors have studied the growth of bulk, freestanding zinc-blende (cubic) GaN layers by plasma-assisted molecular beam epitaxy (PA-MBE). They have established that the best structural properties of freestanding zinc-blende GaN can be achieved with initiation under Ga-rich conditions but without Ga droplet formation. It is difficult to initiate the growth of zinc-blende GaN, but it is even more difficult to sustain the growth of the pure zinc-blende polytype in thick layers without any wurtzite inclusions. In order to grow high quality freestanding cubic GaN layers, it is necessary to maintain the same growth conditions for about 1week. The best quality zinc-blende phase GaN was achieved in the first 10μm of the GaN layers. The authors have produced zinc-blende GaN substrates from our thick bulk GaN layers and they used the side previously attached to the GaAs substrate as the episide of these zinc-blende GaN substrates. They have demonstrated the scalability of the process by growing zinc-blende GaN layers on 2 and 3in. diameter wafers. The growth of freestanding bulk GaN layers has allowed them to refine the value for the lattice parameter of zinc-blende GaN as 4.510±0.005Å. They have demonstrated that the PA-MBE process developed has allowed them to grow freestanding AlxGa1−xN wafers.
Highly stacked InGaAs quantum dot structures grown with two species of As
Authors: Sugaya Takeyoshi , Amano Takeru , Mori Masahiko , Niki Shigeru
Published: March 2010

The authors describe successful formation of highly stacked InGaAs quantum dot (QD) structures grown with molecular beam epitaxy. 100-stack InGaAs QDs are grown without using any strain compensation technique or any degradation in crystal quality. InGaAs QDs are aligned in the growth direction and tend to align in the QD plane. As2-grown multistack InGaAs QD structures have superior optical properties to As4-grown structures at a high growth rate of 1μm∕h, whereas the opposite is true at a lower growth rate. The highest and narrowest photoluminescence spectrum is observed in a highly stacked InGaAs QD structure grown with an As2 source and a high growth rate.
Numerical analysis of dynamic force spectroscopy using a dual-oscillator sensor
Authors: Solares Santiago D. , Hölscher Hendrik
Published: March 2010

A spectral analysis method was recently introduced by Stark et al. [Proc. Natl. Acad. Sci. U.S.A. 99, 8473 (2002)] and implemented by Sahin et al. [Nat. Nanotechnol. 2, 507 (2007)], which is capable of performing simultaneous tapping-mode atomic force microscopy imaging and force spectroscopy. Here the authors report on numerical dual-oscillator simulations that are applied in combination with Fourier data processing software to explore optimized spectroscopy parameters for characterizing polymer and semiconductor samples with the above mentioned spectral analysis method. They also describe various imaging artifacts observed in the simulations, expected limitations of the dual-oscillator model used, and trends of the effect of the most relevant imaging and data processing variables on the quality of the acquired force curves.
Simultaneous atomic force and scanning tunneling microscopy study of the Ge(111)-c(2×8) surface
Authors: Sawada Daisuke , Sugimoto Yoshiaki , Morita Ken-ichi , Abe Masayuki , Morita Seizo
Published: March 2010

In this article, the authors present the simultaneous noncontact atomic force microscopy and scanning tunneling microscopy measurement of the Ge(111)-c(2×8) surface using PtIr-coated Si cantilevers at room temperature. In both frequency shift and time-averaged tunneling current images at constant-height mode, each atom was clearly resolved. The image contrasts differ because the time-averaged tunneling current image is more directly coupled with local density of states than the frequency shift image. They demonstrate the measurement of the site-specific scanning tunneling spectroscopy (STS) spectra, which are in good agreement with typical STS measurements. Moreover, they demonstrate the simultaneous measurements of site-specific frequency shift and tunneling current as a function of tip-sample distance curves. On the Ge(111)-c(2×8) surface, tunneling current dropped at the near-contact region where a strong tip-sample interaction force is observed.
Structural, electrical, and optical characterizations of laser deposited nanometric iron oxide films
Authors: Caricato A. P. , Gorbachuk N. T. , Korduban A. M. , Leggieri G. , Luches A. , Mengucci P. , Mulenko S. A. , Valerini D.
Published: March 2010

The structural, electrical, and optical characteristics of nanometric Fe2O3−x films fabricated on ⟨100⟩ Si and SiO2 substrates by ablating an iron target with a KrF excimer laser in low pressure (0.05–1.0 Pa) O2 atmosphere are reported. The thickness of films fabricated with 4000 laser pulses is ∼80 nm for samples deposited at the lowest pressure (0.05 Pa) and decreases gradually to 50 nm at the highest used pressure (1.0 Pa). The film mean composition results close to FeO at lower pressures (0.05–0.10 Pa) and to Fe2O3 at higher pressures (0.5–1.0 Pa). From glazing incidence x-ray diffraction spectra, it was inferred that deposits are poorly crystallized, especially the ones prepared at relatively high oxygen pressures (0.5–1.0 Pa). Scanning electron microscopy inspections show that surfaces are plane and uniform, with very rare (<0.1 μm−2) submicron droplets. From x-ray reflectivity spectra, surface roughness results very low (0.1–0.5 nm, increasing with O2 pressure). The films present a semiconductor behavior, with electrical energy gaps increasing from 0.43 to 0.93 eV with increasing O2 pressure, while the optical energy gap varies from 1.60 eV (0.05 Pa) to 1.74 eV (1.0 Pa). Very high thermoelectromotive force coefficient values were measured (up to 1.65 mV/K). It is also shown that films present promising gas sensing properties.
Photoluminescence and photoreflectance studies of InAs self-assembled nanostructures on GaAs(631) substrates
Authors: Garcia-Liñan G. , Cruz-Hernández E. , Vázquez-Cortes D. , López-Luna E. , Méndez-García V. H. , López-López M. , Hernandez-Rosas J. , Zamora-Peredo L.
Published: March 2010

The authors report the photoluminescence and photoreflectance characteristics of molecular beam epitaxy grown InAs nanostructures on GaAs (631)-oriented substrates. Prior to the InAs growth, self-assembled nanochannels on the GaAs buffer layer were formed, which later were used as templates for nanostructures formation. Different samples were prepared by varying the amount of InAs from 0.75 to 2 ML (monolayer), 50 nm of GaAs was grown on top as a capping layer. Low temperature photoluminescence spectroscopy showed intense optical transitions in the spectra, their energy position directly depends on the quantity of InAs deposited. The self-assembling of InAs quantum wires (QWRs) at the early stages of growth is suggested. Anisotropy effects in the InAs nanostructures were corroborated by polarized photoluminescence supporting the proposal of formation of QWRs. Photoreflectance spectroscopy at room temperature was also employed to characterize the samples. It is found that in addition to the band-gap energy transition, features associated with quantum confinement in the wetting layer were observed even for very low quantities of InAs deposited.