241 research outputs found
The New Age of Accounting Regulation Canada and the United States
This paper reviews major differences between the accounting regulatory systems in Canada and the United States. In the U.S., the Sarbanes-Oxley Act of 2002 governs responsibilities of management, auditors, and Boards of Directors related to internal control over financial reporting. In Canada, a series of Multilateral Instruments under provincial jurisdiction serves similar objectives. As compared to the U.S., the Canadian system is more decentralized and principles-based allowing a greater degree of responsibility to the accounting profession for standard setting and oversight. The Canadian approach has resulted in weaker regulation, slower implementation, and greater influence by the accounting profession. These findings imply that accounting regulations should be tailored to fit the political and institutional structures of the adopting country
Dissipation signatures of the normal and superfluid phases in torsion pendulum experiments with 3He in aerogel
We present data for energy dissipation factor (Q^{-1}) over a broad
temperature range at various pressures of a torsion pendulum setup used to
study 3He confined in a 98% open silica aerogel. Values for Q^{-1} above T_c
are temperature independent and have a weak pressure dependence. Below T_c, a
deliberate axial compression of the aerogel by 10% widens the range of
metastability for a superfluid Equal Spin Pairing (ESP) state; we observe this
ESP phase on cooling and the B phase on warming over an extended temperature
region. While the dissipation for the B phase tends to zero as T goes to 0,
Q^{-1} exhibits a peak value greater than that at T_c at intermediate
temperatures. Values for Q^{-1} in the ESP phase are consistently higher than
in the B phase and are proportional to \rho_s/\rho until the ESP to B phase
transition is attained. We apply a viscoelastic collision-drag model, which
couples the motion of the helium and the aerogel through a frictional
relaxation time \tau_f. Our dissipation data is not sensitive to the damping
due to the presumed small but non-zero value of \tau_f. The result is that an
additional mechanism to dissipate energy not captured in the collision-drag
model and related to the emergence of the superfluid order must exist. The
extra dissipation below T_c is possibly associated with mutual friction between
the superfluid phases and the clamped normal fluid. The pressure dependence of
the measured dissipation in both superfluid phases is likely related to the
pressure dependence of the gap structure of the "dirty" superfluid. The large
dissipation in the ESP state is consistent with the phase being the A or the
Polar with the order parameter nodes oriented in the plane of the cell and
perpendicular to the aerogel anisotropy axis.Comment: 12 pages, 7 figure
Review of Management Control Systems in Their Organizational and Environmental Context : Managerial Perspective and Control Typology
This paper provides a critical review of literature on management controls and their context. The review indicates that more emphasis has been placed on organizational than environmental factors and that the effectiveness of different controls in different contexts remains practically unaddressed. In general, research has been ad hoc and focused on results-oriented financial controls, short-term efficiency, and individual level of analysis. Even for commonly studied topics (e.g., budget controls), evidence has often been inconsistent and limited to manufacturing organizations, w
Direct measurement of the 14N(p,g)15O S-factor
We have measured the 14N(p,g)15O excitation function for energies in the
range E_p = 155--524 keV. Fits of these data using R-matrix theory yield a
value for the S-factor at zero energy of 1.64(17) keV b, which is significantly
smaller than the result of a previous direct measurement. The corresponding
reduction in the stellar reaction rate for 14N(p,g)15O has a number of
interesting consequences, including an impact on estimates for the age of the
Galaxy derived from globular clusters.Comment: 5 pages, 3 figures, submitted to Phys. Rev. Let
Magneto-Acoustic Spectroscopy in Superfluid 3He-B
We have used the recently discovered acoustic Faraday effect in superfluid
3He to perform high resolution spectroscopy of an excited state of the
superfluid condensate. With acoustic cavity interferometry we measure the
rotation of the plane of polarization of a transverse sound wave propagating in
the direction of magnetic field from which we determine the Zeeman energy of
the excited state. We interpret the Lande g-factor, combined with the
zero-field energies of the state, using the theory of Sauls and Serene to
calculate the strength of f -wave interactions in 3He.Comment: 4 pages, 5 figures, submitted to PRL, Aug 30th, 200
Piezoacoustics for precision control of electrons floating on helium
Piezoelectric surface acoustic waves (SAWs) are powerful for investigating
and controlling elementary and collective excitations in condensed matter. In
semiconductor two-dimensional electron systems SAWs have been used to reveal
the spatial and temporal structure of electronic states, produce quantized
charge pumping, and transfer quantum information. In contrast to
semiconductors, electrons trapped above the surface of superfluid helium form
an ultra-high mobility, two-dimensional electron system home to
strongly-interacting Coulomb liquid and solid states, which exhibit non-trivial
spatial structure and temporal dynamics prime for SAW-based experiments. Here
we report on the coupling of electrons on helium to an evanescent piezoelectric
SAW. We demonstrate precision acoustoelectric transport of as little as ~0.01%
of the electrons, opening the door to future quantized charge pumping
experiments. We also show SAWs are a route to investigating the high-frequency
dynamical response, and relaxational processes, of collective excitations of
the electronic liquid and solid phases of electrons on helium.Comment: Main manuscript: 15 pages, 3 figures; Supplemental Information: 11
pages, 3 figures, 1 tabl
Superfluid Phase Stability of He in Axially Anisotropic Aerogel
Measurements of superfluid He in 98% aerogel demonstrate the existence of
a metastable \emph{A}-like phase and a stable \emph{B}-like phase. It has been
suggested that the relative stability of these two phases is controlled by
anisotropic quasiparticle scattering in the aerogel. Anisotropic scattering
produced by axial compression of the aerogel has been predicted to stabilize
the axial state of superfluid He. To explore this possiblity, we used
transverse acoustic impedance to map out the phase diagram of superfluid He
in a % porous silica aerogel subjected to 17% axial compression. We
have previously shown that axial anisotropy in aerogel leads to optical
birefringence and that optical cross-polarization studies can be used to
characterize such anisotropy. Consequently, we have performed optical
cross-polarization experiments to verify the presence and uniformity of the
axial anisotropy in our aerogel sample. We find that uniform axial anisotropy
introduced by 17% compression does not stabilize the \emph{A}-like phase. We
also find an increase in the supercooling of the \emph{A}-like phase at lower
pressure, indicating a modification to \emph{B}-like phase nucleation in
\emph{globally} anisotropic aerogels.Comment: 4 pages, 4 figures, submitted to LT25 (25th International Conference
on Low Temperature Physics
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