Purpose – The study aims to examine the association between product market competition and corpor... more Purpose – The study aims to examine the association between product market competition and corporate investment decisions on, particularly, risk-taking and investment efficiency. Existing theoretical studies on whether product market competition mitigates or exacerbates agency problems are inconclusive. Prior research generally finds that competition constrains management opportunism in reporting operating performance. However, the association between product market competition and managerial investment decisions has largely been unexplored. Design/methodology/approach – The primary measure of product market competition is the Herfindahl–Hirschman Index. The authors use regression analysis to examine the association between corporate risk-taking and over-investment of free cash flow (FCF) (as dependent variables) and product market competition (as an independent variable). Findings – Using firm-year observations from 1990 to 2010, the authors find that competition encourages manager...
To assess the burden and spectrum of neurological illness in a pediatric intensive care unit and ... more To assess the burden and spectrum of neurological illness in a pediatric intensive care unit and review the associated mortality. Retrospective review of medical records of children (1 mo-16 years) with acute neurological diagnosis admitted in PICU in Aga Khan University hospital from January 2008 to December 2011 was done. Basic demographic, diagnosis, neuro diagnostic procedures performed, therapies and outcomes were done on a structured datasheet. During study period, 231 (19.3%) patients were admitted with acute neurological illnesses in PICU. The mean age was 67 ±50 months, 54% (n=125) was under-five and 138 (59.7%) were males. Out of total, 144 (62.3%) had neurological illness and 87 (37.7%) had neurosurgical diagnosis. In acute neurological illness, 51.5% (n=119) had non-traumatic-coma (NTC) and 10.8% (n=25) had neuromuscular illness. CNS infection (26%, n=60) in structural cause and status epilepticus (10%, n=23) were the most common cause of structural and metabolic type of...
Since the early days of option pricing theory,the assumption that the dividends on the underlying... more Since the early days of option pricing theory,the assumption that the dividends on the underlying stock or index over the life of the contract are known has not been challenged. We examine the sensitivity of index option prices to the assumption of dividend uncertainty. We consider a number of issues related to the forecasting of dividends and build a dividend
Options on common stocks that pay dividends are traditionally priced by assuming that the stock p... more Options on common stocks that pay dividends are traditionally priced by assuming that the stock pays known discrete dividends or a known yield so that the dividend is stochastic but a constant proportion of the stock price. We show in a simple arbitrage-free framework that the Black-...
International Journal of Computer Network and Information Security, 2012
Various security attacks may cause unauthorized access, misuse, modification, or denial of a comp... more Various security attacks may cause unauthorized access, misuse, modification, or denial of a computer network and network accessible resources. To prevent these attacks various authentication means can be used to provide authenticated key exchange protocols. Authenticated key exchange protocol allows the exchange of session key and also authenticates the identities of parties involved in the key exchange. It mathematically binds the agreed key to other agreed upon data such as shared secret keys, passwords and public/private key pairs. The reliability and security of the authentication protocol can be increased by combining two factors in the same authentication protocol. Many two-factor authenticated schemes have been proposed due to its usefulness. The main focus of this paper is to propose an enhanced two-factor authenticated scheme that can resist various security attacks in network by eliminating the attack races by matching it with knowledge available in the network as well as provide user anonymity.
Larch mitochondria contain a 'native' tRNA His which is absent from angiosperms. Sequence compari... more Larch mitochondria contain a 'native' tRNA His which is absent from angiosperms. Sequence comparisons of genomic DNA and cDNA obtained from unprocessed primary transcripts of the larch mitochondrial gene trnH encoding this tRNA revealed three nucleotide discrepancies. These three nucleotide alterations, in the acceptor stem, D stem and anticodon stem respectively, are conversions of genomic cytidines to thymidines in the cDNA (uridines in the tRNA) and thus resemble the RNA editing events observed in nearly all plant mitochondrial mRNAs. Two cases of editing affecting mitochondrial tRNAs from angiosperms have already been described, but we present here the first example of such events in a gymnosperm mitochondrial tRNA. All three editing events correct mismatched C•A base pairs which appear when folding the gene sequence into the standard cloverleaf structure, thereby improving the secondary structure of the tRNA. When incubated with a heterologous potato mitochondrial processing extract, only the edited form of the larch mitochondrial tRNA His precursor was efficiently processed in vitro. These data strongly suggest that editing of larch mitochondrial tRNA His is a prerequisite for its processing.
This study investigates the intertemporal relation between daily stock index change and volume tu... more This study investigates the intertemporal relation between daily stock index change and volume turnover of four countries. The results show that, in the sample period 1996-2000, the pricevolume relations are differential across countries. Index change leads volume turnover for US stock market. When daily stock prices go up (down) strongly, subsequent volume turnover fall (rise). On the other hand, stock prices do not exhibit a clear pattern after a significant change in volume turnover. Moreover, UK and Japanese markets exhibit a comtemporary or independent relation while Taiwanese market shows a causal relation between index change and volume. The distinct relations across countries are ascribed to the behavior of market participant structure. Since unconditional volume cannot help forecast prices, we characterize volume by time-series models to measure abnormal volume. We show that abnormal volume have weak predictable power on prices. An Investigation on the Intertemporal Relation between Stock Index and Volume Financial academicians and practitioners are leaned to believe that trading volume contain important information. A number of research shed light on the role of volume played in price determination (e.g., Karpoff (1987), Gallant, Rossi, and Tauchen (1992), and Lo and Wang (2000) among others). Nevertheless, the price-volume relation is not crystal yet and has an extensive room to explore. The complexity of financial market behavior makes the price-volume relation sophisticated (discussed in section I). Hiemstra and Jones (1994), for example, conclude a nonlinear causal relation between price and volume. It may imply that many factors, macro and micro, known or unknown, may simultaneously affect either of both of price and volume. Thus the price-volume relation could vary over time and is difficult to examine. The purpose of this paper is to investigate the intertemporal relation between stock index change and aggregate volume turnover. There have been a number of studies related to the pricevolume relations of individual stocks, while research of aggregate price and volume are not plenty. This topic is important for explaining market behavior. If past volume lead prices, it contributes to the predictability on stock price. On the other hand, if past prices can predict volume, it reflects that investors mainly respond to price changes. Lagged prices, therefore, should be modeled in current volume. In contrast to Hiemstra and Jones' (1994) nonlinear relation, we postulate that the indexvolume relation is linear but not strictly stationary. In other words, we allow the price-volume relation to vary over time. This framework is simple but intuitive. We conjecture that there should be some kind of unconditional time-series relation between index and volume in normal periods while some other relations during certain particular periods. Specifically, we conduct the nested causal tests developed by Chen and Lee (1990). These tests employ several hypotheses to identify the relation between variables and are consistent with nonlinear tests. The results show that five of six indices have no causality from volume to prices. We then assume that "abnormal volume" have a significant impact on price. Technically, we employ the ARMA model with three types of outliers, namely, additive, temporal-change, and level-shift outliers to characterize volume. We use the difference between the actual and forecasted volume by the ARMA-outlier model to be an "abnormal volume" proxy. The results show that past "abnormal volume" have some predicted power on index change. The remainder of this paper is structured as follows. Section I reviews the price-volume relations. Section II discusses the data sample. Section III summarizes the causality tests of Chen and Lee (1990). Section IV introduces the abnormal volume model. Section V reports the empirical results. Finally, section VI concludes the findings.
ABSTRACT This paper investigates the behavior of stock and option prices around block trades in s... more ABSTRACT This paper investigates the behavior of stock and option prices around block trades in stocks. The results indicate that for both uptick and downtick block trades the stock prices adjust within a fifteen minute period after the block trade. Moreover, for uptick blocks there is no ...
Abstract This study examines the effect of changes in margin requirements on stock price volatili... more Abstract This study examines the effect of changes in margin requirements on stock price volatility. We examine the possibility that the impact of margin requirements varies with a stock's degree of speculative interest. Using four alternative measures of speculative interest, we ...
Abstract This study evaluates the effect of SEC-ordered sus-pensions on securities&am... more Abstract This study evaluates the effect of SEC-ordered sus-pensions on securities' returns, volatility, and trading volume during 1963-1987. It is found that there is a per-manent devaluation of these securities during the sus-pension. This result, however, is sensitive to the an- ...
The Quarterly Review of Economics and Finance, 1998
Existing literature documents a positive stock market reaction to the announcement of long-term p... more Existing literature documents a positive stock market reaction to the announcement of long-term performance plans as well a~ subsequently higher growth rates in earnings per share and return on equity (ROE). These findings are consistent with the notion that such performance plans provide an incentive to managers to reduce the magnitude of agency conflict present within the modern corporation. Using a paired sample design, this paper addresses the specific sources of superior post-adoption ROE performance. We fail to observe any evidence of improvement in total sales, total asset turnover or the management of long-term debt. We find that the post-adoption
This paper investigates the impact of the listing of options on the Nikkei Stock Average (NSA) on... more This paper investigates the impact of the listing of options on the Nikkei Stock Average (NSA) on the volatility, bid-ask spread and trading volume for stocks listed in the First Section of the Tokyo Stock Exchange. Our results indicate that trading volume, volatility, and bid-ask spreads decline for the stocks contained in the Nikkei 225 Index after the listing of the index options. Cross-sectional regressions that control for changes in spread, volume, and price indicate that the options listing is associated with decreases in volatility for the index stocks. We conjecture that the observed results are consistent with the hypothesis that the advent of options trading causes a migration of speculative and market-wide information-oriented trading activity from the underlying market to the options market.
Recently, historical price series along with the dividend series have been used to severely quest... more Recently, historical price series along with the dividend series have been used to severely question the Efficient Markets Hypothesis. The literature suggests that the stock prices vary too much to be explained by subsequent changes in dividends. It is argued in this paper that these results require the assumption of stationarity of the price process and that this assumption is not compatible with the random walk model of Efticient Markets. A non-stationary dividend process, which is compatible with the random walk model of Efficient Markets, results in a reversal of earlier results. The new results are shown to be consistent with the empirical findings. Simulations are run to verify the results.
We examine a sample of "rms that reset the exercise prices on their executive options. These repr... more We examine a sample of "rms that reset the exercise prices on their executive options. These repricings follow a period of about one year of poor "rm-speci"c performance in which the average "rm loses one-fourth of its value. No other o!setting changes to option terms or compensation are made, and many "rms reprice more than once. Without repricing, a majority of the options would have been at-the-money within two years. We "nd that when faced with circumstances in which repricing might be chosen, "rms with greater agency problems, smaller size, and insider-dominated boards are more likely to reprice.
The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolid... more The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolidation of a poroelastic half-space caused by axisymmetric surface loads. The fluid and solid constituents of the poroelastic medium are compressible and its permeability in the vertical direction is different from its permeability in the horizontal direction. An analytical solution of the governing equations is obtained by taking the displacements and the pore pressure as the basic state variables and using a combination of the Laplace and Hankel transforms. The problem of an axisymmetric normal load is discussed in detail. An explicit analytical solution is obtained for normal disc loading. Detailed numerical computations reveal that the anisotropy in permeability as well as the compressibilities of the fluid and solid constituents of the poroelastic medium have significant effects on the consolidation of the half-space. The anisotropy in permeability may accelerate the consolidation process and may lead to a dilution in the theoretical prediction of the Mandel-Cryer effect. The compressibility of the solid constituents may also accelerate the consolidation process.
The dielectric relaxation studies of different molar concentrations of ethanol in the binary mixt... more The dielectric relaxation studies of different molar concentrations of ethanol in the binary mixtures of ethanol and N, N-dimethylacetamide in benzene solutions have been studied at 9.883 GHz by using standard standing microwave techniques and Gopala Krishna's [Trans Faraday Soc, 33 (1957) 767] single frequency concentration variation method at different temperatures (25, 30, 35 and 40°C). It is found that dielectric relaxation time varies non-linearly with the variation in molar concentration of ethanol in the whole concentration range of the binary mixture. The solute-solute and solutesolvent types of molecular associations have been proposed. The energy parameters (ΔH ε , ΔF ε , ΔS ε) for the dielectric relaxation process of binary mixtures containing 50% molar concentration of ethanol have been calculated at the respective given temperatures. Comparison has been made with the corresponding energy parameters for viscous flow process. It is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process.
Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain... more Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain enormous amount of heavy metals. Microorganisms including fungi have been reported to exclude heavy metals from wastewater through bioaccumulation and biosorption at low cost and in eco-friendly way. An attempt was, therefore, made to isolate fungi from sites contaminated with heavy metals for higher tolerance and removal of heavy metals from wastewater. Seventy-six fungal isolates tolerant to heavy metals like Pb, Cd, Cr and Ni were isolated from sewage, sludge and industrial effluents containing heavy metals. Four fungi (Phanerochaete chrysosporium, Aspegillus awamori, Aspergillus flavus, Trichoderma viride) also were included in this study. The majority of the fungal isolates were able to tolerate up to 400 ppm concentration of Pb, Cd, Cr and Ni. The most heavy metal tolerant fungi were studied for removal of heavy metals from liquid media at 50 ppm concentration. Results indicated removal of substantial amount of heavy metals by some of the fungi. With respect to Pb, Cd, Cr and Ni, maximum uptake of 59.67, 16.25, 0.55, and 0.55 mg/g was observed by fungi Pb3 (Aspergillus terreus), Trichoderma viride, Cr8 (Trichoderma longibrachiatum), and isolate Ni27 (A. niger) respectively. This indicated the potential of these fungi as biosorbent for removal of heavy metals from wastewater and industrial effluents containing higher concentration of heavy metals.
An analytical solution is obtained of the fully coupled diffusion-deformation system of equations... more An analytical solution is obtained of the fully coupled diffusion-deformation system of equations governing the quasi-static plane strain deformation of a poroelastic half-space with anisotropic permeability and compressible constituents. The stresses and the pore pressure are taken as the basic state variables. Displacements are obtained by integrating the coupled constitutive relations. The problem of surface loads is discussed in detail. Explicit analytical solutions are derived for normal line loading, shear line loading and normal strip loading. The permeability anisotropy is found to have a significant effect on the quasi-static deformation of the half-space. However, in the drained and undrained limits, the anisotropy has no effect. The stresses in the drained and undrained states are independent of the poroelastic parameters. Numerical computation of the pore pressure indicates that ignoring permeability anisotropy may lead to an overestimation of the pore pressure at points vertically below the point of normal loading. Further, anisotropy in permeability may lead to a dilution in the theoretical prediction of the Mandel-Cryer Effect.
Purpose – The study aims to examine the association between product market competition and corpor... more Purpose – The study aims to examine the association between product market competition and corporate investment decisions on, particularly, risk-taking and investment efficiency. Existing theoretical studies on whether product market competition mitigates or exacerbates agency problems are inconclusive. Prior research generally finds that competition constrains management opportunism in reporting operating performance. However, the association between product market competition and managerial investment decisions has largely been unexplored. Design/methodology/approach – The primary measure of product market competition is the Herfindahl–Hirschman Index. The authors use regression analysis to examine the association between corporate risk-taking and over-investment of free cash flow (FCF) (as dependent variables) and product market competition (as an independent variable). Findings – Using firm-year observations from 1990 to 2010, the authors find that competition encourages manager...
To assess the burden and spectrum of neurological illness in a pediatric intensive care unit and ... more To assess the burden and spectrum of neurological illness in a pediatric intensive care unit and review the associated mortality. Retrospective review of medical records of children (1 mo-16 years) with acute neurological diagnosis admitted in PICU in Aga Khan University hospital from January 2008 to December 2011 was done. Basic demographic, diagnosis, neuro diagnostic procedures performed, therapies and outcomes were done on a structured datasheet. During study period, 231 (19.3%) patients were admitted with acute neurological illnesses in PICU. The mean age was 67 ±50 months, 54% (n=125) was under-five and 138 (59.7%) were males. Out of total, 144 (62.3%) had neurological illness and 87 (37.7%) had neurosurgical diagnosis. In acute neurological illness, 51.5% (n=119) had non-traumatic-coma (NTC) and 10.8% (n=25) had neuromuscular illness. CNS infection (26%, n=60) in structural cause and status epilepticus (10%, n=23) were the most common cause of structural and metabolic type of...
Since the early days of option pricing theory,the assumption that the dividends on the underlying... more Since the early days of option pricing theory,the assumption that the dividends on the underlying stock or index over the life of the contract are known has not been challenged. We examine the sensitivity of index option prices to the assumption of dividend uncertainty. We consider a number of issues related to the forecasting of dividends and build a dividend
Options on common stocks that pay dividends are traditionally priced by assuming that the stock p... more Options on common stocks that pay dividends are traditionally priced by assuming that the stock pays known discrete dividends or a known yield so that the dividend is stochastic but a constant proportion of the stock price. We show in a simple arbitrage-free framework that the Black-...
International Journal of Computer Network and Information Security, 2012
Various security attacks may cause unauthorized access, misuse, modification, or denial of a comp... more Various security attacks may cause unauthorized access, misuse, modification, or denial of a computer network and network accessible resources. To prevent these attacks various authentication means can be used to provide authenticated key exchange protocols. Authenticated key exchange protocol allows the exchange of session key and also authenticates the identities of parties involved in the key exchange. It mathematically binds the agreed key to other agreed upon data such as shared secret keys, passwords and public/private key pairs. The reliability and security of the authentication protocol can be increased by combining two factors in the same authentication protocol. Many two-factor authenticated schemes have been proposed due to its usefulness. The main focus of this paper is to propose an enhanced two-factor authenticated scheme that can resist various security attacks in network by eliminating the attack races by matching it with knowledge available in the network as well as provide user anonymity.
Larch mitochondria contain a 'native' tRNA His which is absent from angiosperms. Sequence compari... more Larch mitochondria contain a 'native' tRNA His which is absent from angiosperms. Sequence comparisons of genomic DNA and cDNA obtained from unprocessed primary transcripts of the larch mitochondrial gene trnH encoding this tRNA revealed three nucleotide discrepancies. These three nucleotide alterations, in the acceptor stem, D stem and anticodon stem respectively, are conversions of genomic cytidines to thymidines in the cDNA (uridines in the tRNA) and thus resemble the RNA editing events observed in nearly all plant mitochondrial mRNAs. Two cases of editing affecting mitochondrial tRNAs from angiosperms have already been described, but we present here the first example of such events in a gymnosperm mitochondrial tRNA. All three editing events correct mismatched C•A base pairs which appear when folding the gene sequence into the standard cloverleaf structure, thereby improving the secondary structure of the tRNA. When incubated with a heterologous potato mitochondrial processing extract, only the edited form of the larch mitochondrial tRNA His precursor was efficiently processed in vitro. These data strongly suggest that editing of larch mitochondrial tRNA His is a prerequisite for its processing.
This study investigates the intertemporal relation between daily stock index change and volume tu... more This study investigates the intertemporal relation between daily stock index change and volume turnover of four countries. The results show that, in the sample period 1996-2000, the pricevolume relations are differential across countries. Index change leads volume turnover for US stock market. When daily stock prices go up (down) strongly, subsequent volume turnover fall (rise). On the other hand, stock prices do not exhibit a clear pattern after a significant change in volume turnover. Moreover, UK and Japanese markets exhibit a comtemporary or independent relation while Taiwanese market shows a causal relation between index change and volume. The distinct relations across countries are ascribed to the behavior of market participant structure. Since unconditional volume cannot help forecast prices, we characterize volume by time-series models to measure abnormal volume. We show that abnormal volume have weak predictable power on prices. An Investigation on the Intertemporal Relation between Stock Index and Volume Financial academicians and practitioners are leaned to believe that trading volume contain important information. A number of research shed light on the role of volume played in price determination (e.g., Karpoff (1987), Gallant, Rossi, and Tauchen (1992), and Lo and Wang (2000) among others). Nevertheless, the price-volume relation is not crystal yet and has an extensive room to explore. The complexity of financial market behavior makes the price-volume relation sophisticated (discussed in section I). Hiemstra and Jones (1994), for example, conclude a nonlinear causal relation between price and volume. It may imply that many factors, macro and micro, known or unknown, may simultaneously affect either of both of price and volume. Thus the price-volume relation could vary over time and is difficult to examine. The purpose of this paper is to investigate the intertemporal relation between stock index change and aggregate volume turnover. There have been a number of studies related to the pricevolume relations of individual stocks, while research of aggregate price and volume are not plenty. This topic is important for explaining market behavior. If past volume lead prices, it contributes to the predictability on stock price. On the other hand, if past prices can predict volume, it reflects that investors mainly respond to price changes. Lagged prices, therefore, should be modeled in current volume. In contrast to Hiemstra and Jones' (1994) nonlinear relation, we postulate that the indexvolume relation is linear but not strictly stationary. In other words, we allow the price-volume relation to vary over time. This framework is simple but intuitive. We conjecture that there should be some kind of unconditional time-series relation between index and volume in normal periods while some other relations during certain particular periods. Specifically, we conduct the nested causal tests developed by Chen and Lee (1990). These tests employ several hypotheses to identify the relation between variables and are consistent with nonlinear tests. The results show that five of six indices have no causality from volume to prices. We then assume that "abnormal volume" have a significant impact on price. Technically, we employ the ARMA model with three types of outliers, namely, additive, temporal-change, and level-shift outliers to characterize volume. We use the difference between the actual and forecasted volume by the ARMA-outlier model to be an "abnormal volume" proxy. The results show that past "abnormal volume" have some predicted power on index change. The remainder of this paper is structured as follows. Section I reviews the price-volume relations. Section II discusses the data sample. Section III summarizes the causality tests of Chen and Lee (1990). Section IV introduces the abnormal volume model. Section V reports the empirical results. Finally, section VI concludes the findings.
ABSTRACT This paper investigates the behavior of stock and option prices around block trades in s... more ABSTRACT This paper investigates the behavior of stock and option prices around block trades in stocks. The results indicate that for both uptick and downtick block trades the stock prices adjust within a fifteen minute period after the block trade. Moreover, for uptick blocks there is no ...
Abstract This study examines the effect of changes in margin requirements on stock price volatili... more Abstract This study examines the effect of changes in margin requirements on stock price volatility. We examine the possibility that the impact of margin requirements varies with a stock's degree of speculative interest. Using four alternative measures of speculative interest, we ...
Abstract This study evaluates the effect of SEC-ordered sus-pensions on securities&am... more Abstract This study evaluates the effect of SEC-ordered sus-pensions on securities' returns, volatility, and trading volume during 1963-1987. It is found that there is a per-manent devaluation of these securities during the sus-pension. This result, however, is sensitive to the an- ...
The Quarterly Review of Economics and Finance, 1998
Existing literature documents a positive stock market reaction to the announcement of long-term p... more Existing literature documents a positive stock market reaction to the announcement of long-term performance plans as well a~ subsequently higher growth rates in earnings per share and return on equity (ROE). These findings are consistent with the notion that such performance plans provide an incentive to managers to reduce the magnitude of agency conflict present within the modern corporation. Using a paired sample design, this paper addresses the specific sources of superior post-adoption ROE performance. We fail to observe any evidence of improvement in total sales, total asset turnover or the management of long-term debt. We find that the post-adoption
This paper investigates the impact of the listing of options on the Nikkei Stock Average (NSA) on... more This paper investigates the impact of the listing of options on the Nikkei Stock Average (NSA) on the volatility, bid-ask spread and trading volume for stocks listed in the First Section of the Tokyo Stock Exchange. Our results indicate that trading volume, volatility, and bid-ask spreads decline for the stocks contained in the Nikkei 225 Index after the listing of the index options. Cross-sectional regressions that control for changes in spread, volume, and price indicate that the options listing is associated with decreases in volatility for the index stocks. We conjecture that the observed results are consistent with the hypothesis that the advent of options trading causes a migration of speculative and market-wide information-oriented trading activity from the underlying market to the options market.
Recently, historical price series along with the dividend series have been used to severely quest... more Recently, historical price series along with the dividend series have been used to severely question the Efficient Markets Hypothesis. The literature suggests that the stock prices vary too much to be explained by subsequent changes in dividends. It is argued in this paper that these results require the assumption of stationarity of the price process and that this assumption is not compatible with the random walk model of Efticient Markets. A non-stationary dividend process, which is compatible with the random walk model of Efficient Markets, results in a reversal of earlier results. The new results are shown to be consistent with the empirical findings. Simulations are run to verify the results.
We examine a sample of "rms that reset the exercise prices on their executive options. These repr... more We examine a sample of "rms that reset the exercise prices on their executive options. These repricings follow a period of about one year of poor "rm-speci"c performance in which the average "rm loses one-fourth of its value. No other o!setting changes to option terms or compensation are made, and many "rms reprice more than once. Without repricing, a majority of the options would have been at-the-money within two years. We "nd that when faced with circumstances in which repricing might be chosen, "rms with greater agency problems, smaller size, and insider-dominated boards are more likely to reprice.
The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolid... more The fully coupled Biot quasi-static theory of linear poroelasticity is used to study the consolidation of a poroelastic half-space caused by axisymmetric surface loads. The fluid and solid constituents of the poroelastic medium are compressible and its permeability in the vertical direction is different from its permeability in the horizontal direction. An analytical solution of the governing equations is obtained by taking the displacements and the pore pressure as the basic state variables and using a combination of the Laplace and Hankel transforms. The problem of an axisymmetric normal load is discussed in detail. An explicit analytical solution is obtained for normal disc loading. Detailed numerical computations reveal that the anisotropy in permeability as well as the compressibilities of the fluid and solid constituents of the poroelastic medium have significant effects on the consolidation of the half-space. The anisotropy in permeability may accelerate the consolidation process and may lead to a dilution in the theoretical prediction of the Mandel-Cryer effect. The compressibility of the solid constituents may also accelerate the consolidation process.
The dielectric relaxation studies of different molar concentrations of ethanol in the binary mixt... more The dielectric relaxation studies of different molar concentrations of ethanol in the binary mixtures of ethanol and N, N-dimethylacetamide in benzene solutions have been studied at 9.883 GHz by using standard standing microwave techniques and Gopala Krishna's [Trans Faraday Soc, 33 (1957) 767] single frequency concentration variation method at different temperatures (25, 30, 35 and 40°C). It is found that dielectric relaxation time varies non-linearly with the variation in molar concentration of ethanol in the whole concentration range of the binary mixture. The solute-solute and solutesolvent types of molecular associations have been proposed. The energy parameters (ΔH ε , ΔF ε , ΔS ε) for the dielectric relaxation process of binary mixtures containing 50% molar concentration of ethanol have been calculated at the respective given temperatures. Comparison has been made with the corresponding energy parameters for viscous flow process. It is found that the dielectric relaxation process can be treated as the rate process like the viscous flow process.
Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain... more Wastewater particularly from electroplating, paint, leather, metal and tanning industries contain enormous amount of heavy metals. Microorganisms including fungi have been reported to exclude heavy metals from wastewater through bioaccumulation and biosorption at low cost and in eco-friendly way. An attempt was, therefore, made to isolate fungi from sites contaminated with heavy metals for higher tolerance and removal of heavy metals from wastewater. Seventy-six fungal isolates tolerant to heavy metals like Pb, Cd, Cr and Ni were isolated from sewage, sludge and industrial effluents containing heavy metals. Four fungi (Phanerochaete chrysosporium, Aspegillus awamori, Aspergillus flavus, Trichoderma viride) also were included in this study. The majority of the fungal isolates were able to tolerate up to 400 ppm concentration of Pb, Cd, Cr and Ni. The most heavy metal tolerant fungi were studied for removal of heavy metals from liquid media at 50 ppm concentration. Results indicated removal of substantial amount of heavy metals by some of the fungi. With respect to Pb, Cd, Cr and Ni, maximum uptake of 59.67, 16.25, 0.55, and 0.55 mg/g was observed by fungi Pb3 (Aspergillus terreus), Trichoderma viride, Cr8 (Trichoderma longibrachiatum), and isolate Ni27 (A. niger) respectively. This indicated the potential of these fungi as biosorbent for removal of heavy metals from wastewater and industrial effluents containing higher concentration of heavy metals.
An analytical solution is obtained of the fully coupled diffusion-deformation system of equations... more An analytical solution is obtained of the fully coupled diffusion-deformation system of equations governing the quasi-static plane strain deformation of a poroelastic half-space with anisotropic permeability and compressible constituents. The stresses and the pore pressure are taken as the basic state variables. Displacements are obtained by integrating the coupled constitutive relations. The problem of surface loads is discussed in detail. Explicit analytical solutions are derived for normal line loading, shear line loading and normal strip loading. The permeability anisotropy is found to have a significant effect on the quasi-static deformation of the half-space. However, in the drained and undrained limits, the anisotropy has no effect. The stresses in the drained and undrained states are independent of the poroelastic parameters. Numerical computation of the pore pressure indicates that ignoring permeability anisotropy may lead to an overestimation of the pore pressure at points vertically below the point of normal loading. Further, anisotropy in permeability may lead to a dilution in the theoretical prediction of the Mandel-Cryer Effect.
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