20,075 research outputs found

    Investor Reactions to Information Disclosure: Can Providing Public Information About Firms' Pollution Improve Environmental Performance?

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    Information disclosure has been touted as a powerful tool to effect change in environmental quality. Nascent efforts to augment federal information disclosure have begun in Georgia. We conduct the first empirical analysis of investor reactions to a Pollutant Release and Transfer Register (PRTR) outside of the United States. In contrast to the U.S. studies, we find no evidence of negative investor reactions to firms listed on Japan's PRTR. We identify several institutional reasons for these contradictory results. Our results suggest that PRTRs may not have the same effect in all locations and thus further empirical studies of the burgeoning number of PRTRs being implemented globally are warranted. Working Paper Number 2005-001

    Can Encouraging Voluntary Development of Environmental Management Systems Augment Existing Regulations?

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    Encouraging firms to voluntarily develop environmental management systems (EMSs) has been described as a potential policy tool for achieving environmental objectives in Georgia. We survey current thinking on the subject and note several shortcomings in current methods used to evaluate what motivates private firms to adopt comprehensive EMSs. Using a unique dataset of environmental management practices of Japanese manufacturers, we find that consumer pressures, regulatory pressures, and market power are major factors that motivate firms to develop comprehensive EMSs. We also find that after controlling for self-selection bias in survey response, the effects of regulatory pressures become more significant and larger in magnitude. These results suggest that although encouraging development of EMSs has the potential to augment existing regulations, the regulatory tools are fundamental to the success of such voluntary approaches. Working Paper Number 2005-001

    Synchronised laser chaos communication: statistical investigation of an experimental system

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    The paper is concerned with analyzing data from an experimental antipodal laser-based chaos shift-keying communication system. Binary messages are embedded in a chaotically behaving laser wave which is transmitted through a fiber-optic cable and are decoded at the receiver using a second laser synchronized with the emitter laser. Instrumentation in the experimental system makes it particularly interesting to be able to empirically analyze both optical noise and synchronization error as well as bit error rate. Both the noise and error are found to significantly depart in distribution from independent Gaussian. The conclusion from bit error rate results is that the antipodal laser chaos shift-keying system can offer a feasible approach to optical communication. The non-Gaussian optical noise and synchronous error results are a challenge to current theoretical modelling

    Charge dynamics in thermally and doping induced insulator-metal transitions of (Ti1-xVx)2O3

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    Charge dynamics of (Ti1-xVx)2O3 with x=0-0.06 has been investigated by measurements of charge transport and optical conductivity spectra in a wide temperature range of 2-600K with the focus on the thermally and doping induced insulator-metal transitions (IMTs). The optical conductivity peaks for the interband transitions in the 3d t2g manifold are observed in the both insulating and metallic states, while their large variation (by ~0.4 eV) with change of temperature and doping level scales with that of the Ti-Ti dimer bond length, indicating the weakened singlet bond in the course of IMTs. The thermally and V-doping induced IMTs are driven with the increase in carrier density by band-crossing and hole-doping, respectively, in contrast to the canonical IMT of correlated oxides accompanied by the whole collapse of the Mott gap.Comment: 4 pages, 4 figure

    Linear-response theory of the longitudinal spin Seebeck effect

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    We theoretically investigate the longitudinal spin Seebeck effect, in which the spin current is injected from a ferromagnet into an attached nonmagnetic metal in a direction parallel to the temperature gradient. Using the fact that the phonon heat current flows intensely into the attached nonmagnetic metal in this particular configuration, we show that the sign of the spin injection signal in the longitudinal spin Seebeck effect can be opposite to that in the conventional transverse spin Seebeck effect when the electron-phonon interaction in the nonmagnetic metal is sufficiently large. Our linear-response approach can explain the sign reversal of the spin injection signal recently observed in the longitudinal spin Seebeck effect.Comment: Proc. of ICM 2012 (Accepted for publication in J. Korean Phys. Soc.), typos correcte

    Distribution of Faraday Rotation Measure in Jets from Active Galactic Nuclei II. Prediction from our Sweeping Magnetic Twist Model for the Wiggled Parts of AGN Jets and Tails

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    Distributions of Faraday rotation measure (FRM) and the projected magnetic field derived by a 3-dimensional simulation of MHD jets are investigated based on our "sweeping magnetic twist model". FRM and Stokes parameters were calculated to be compared with radio observations of large scale wiggled AGN jets on kpc scales. We propose that the FRM distribution can be used to discuss the 3-dimensional structure of magnetic field around jets and the validity of existing theoretical models, together with the projected magnetic field derived from Stokes parameters. In the previous paper, we investigated the basic straight part of AGN jets by using the result of a 2-dimensional axisymmetric simulation. The derived FRM distribution has a general tendency to have a gradient across the jet axis, which is due to the toroidal component of the magnetic field generated by the rotation of the accretion disk. In this paper, we consider the wiggled structure of the AGN jets by using the result of a 3-dimensional simulation. Our numerical results show that the distributions of FRM and the projected magnetic field have a clear correlation with the large scale structure of the jet itself, namely, 3-dimensional helix. Distributions, seeing the jet from a certain direction, show a good matching with those in a part of 3C449 jet. This suggests that the jet has a helical structure and that the magnetic field (especially the toroidal component) plays an important role in the dynamics of the wiggle formation because it is due to a current-driven helical kink instability in our model.Comment: Accepted for publication in Ap

    Conical Singular Solutions in (2+1)-Dimensional Gravity Employing the ADM Canonical Formalism

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    Topological solutions in the (2+1)-dimensional Einstein theory of gravity are studied within the ADM canonical formalism. It is found that a conical singularity appears in the closed de Sitter universe solution as a topological defect in the case of the Einstein theory with a cosmological constant. Quantum effects on the conical singularity are studied using the de Broglie-Bohm interpretation. Finite quantum tunneling effects are obtained for the closed de Sitter universe, while no quantum effects are obtained for an open universe.Comment: 15 pages, 3 figure
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