7,972 research outputs found
An investigation into the time-saving benefits of using a computerised taxation program
Software programs designed to calculate the tax liability of individuals and other types of tax entity are being designed and used with increasing frequency. Research done in the United States of America appears to indicate that these programs do not achieve any saving in time and, in fact, may take longer to use than to complete a tax return by hand. As the South African revenue collection system appears to be moving closer to a self-assessment system, where the calculation of tax owing will be the responsibility of the taxpayer, the research essay sets out to determine whether there is a saving in time when calculating a tax liability using a tax software program, instead of calculating it by hand. In addition, the research aims to determine how much time, on average, is saved or lost, using such a program, and whether there is any correlation between the time taken to perform a calculation by hand and that using the software program. It does so by comparing the average estimated time it would take to complete tax calculations for individuals by hand with the average time taken to complete the same tax calculations using a tax software program. The average time taken to do the calculations by hand is based on the time allocation given for questions by the authors of a published question bank for university students. The time taken using software is determined by using a stop-watch to time each question being processed. The results, subject to assumptions made in carrying out the research, show that there is a substantial saving in time using the software program. Based on the data, however, the results indicate a weak correlation between the estimated time taken to do a calculation by hand and the estimated time using the software program. Possible reasons for the weak correlation are discussed. A recommendation is also made for the standardization and certification of existing tax calculation software
LANDSAT-1 and LANDSAT-2 flight evaluation report
There are no author-identified significant results in this report
Ventilatory Phenotypes among Four Strains of Adult Rats.
Our purpose in this study was to identify different ventilatory phenotypes among four different strains of rats. We examined 114 rats from three in-house, inbred strains and one outbred strain: Brown Norway (BN;n = 26), Dahl salt-sensitive (n = 24), Fawn-hooded Hypertensive (FHH: n = 27), and outbred Sprague-Dawley rats (SD; n = 37). We measured eupneic (room air) breathing and the ventilatory responses to hypoxia (12% O2-88% N2), hypercapnia (7% CO2), and two levels of submaximal exercise. Primary strain differences were between BN and the other strains. BN rats had a relatively attenuated ventilatory response to CO2 (P \u3c 0.001), an accentuated ventilatory response to exercise (P \u3c 0.05), and an accentuated ventilatory roll-off during hypoxia (P \u3c 0.05). Ventilation during hypoxia was lower than other strains, but hyperventilation during hypoxia was equal to the other strains (P \u3e 0.05), indicating that the metabolic rate during hypoxia decreased more in BN rats than in other strains. Another strain difference was in the frequency and timing components of augmented breaths, where FHH rats frequently differed from the other strains, and the BN rats had the longest expiratory time of the augmented breaths (probably secondary to the blunted CO2 sensitivity). These strain differences not only provide insight into physiological mechanisms but also indicate traits (such as CO2 sensitivity) that are genetically regulated. Finally, the data establish a foundation for physiological genomic studies aimed at elucidating the genetics of these ventilatory control mechanisms
Heat transport of clean spin-ladders coupled to phonons: Umklapp scattering and drag
We study the low-temperature heat transport in clean two-leg spin ladder
compounds coupled to three-dimensional phonons. We argue that the very large
heat conductivities observed in such systems can be traced back to the
existence of approximate symmetries and corresponding weakly violated
conservation laws of the effective (gapful) low--energy model, namely
pseudo-momenta. Depending on the ratios of spin gaps and Debye energy and on
the temperature, the magnetic contribution to the heat conductivity can be
positive or negative, and exhibit an activated or anti-activated behavior. In
most regimes, the magnetic heat conductivity is dominated by the spin-phonon
drag: the excitations of the two subsystems have almost the same drift
velocity, and this allows for an estimate of the ratio of the magnetic and
phononic contributions to the heat conductivity.Comment: revised version, 8 pages, 3 figures, added appendi
Fractional Operators, Dirichlet Averages, and Splines
Fractional differential and integral operators, Dirichlet averages, and
splines of complex order are three seemingly distinct mathematical subject
areas addressing different questions and employing different methodologies. It
is the purpose of this paper to show that there are deep and interesting
relationships between these three areas. First a brief introduction to
fractional differential and integral operators defined on Lizorkin spaces is
presented and some of their main properties exhibited. This particular approach
has the advantage that several definitions of fractional derivatives and
integrals coincide. We then introduce Dirichlet averages and extend their
definition to an infinite-dimensional setting that is needed to exhibit the
relationships to splines of complex order. Finally, we focus on splines of
complex order and, in particular, on cardinal B-splines of complex order. The
fundamental connections to fractional derivatives and integrals as well as
Dirichlet averages are presented
Microscopic Theory for the Markovian Decay of Magnetization Fluctuations in Nanomagnets
We present a microscopic theory for the phonon-driven decay of the
magnetization fluctuations in a wide class of nanomagnets where the dominant
energy is set by isotropic exchange and/or uniaxial anisotropy. Based on the
Zwanzig-Mori projection formalism, the theory reveals that the magnetization
fluctuations are governed by a single decay rate , which we further
identify with the zero-frequency portion of the associated self-energy. This
dynamical decoupling from the remaining slow degrees of freedom is attributed
to a conservation law and the discreteness of the energy spectrum, and explains
the omnipresent mono-exponential decay of the magnetization over several
decades in time, as observed experimentally. A physically transparent
analytical expression for is derived which highlights the three
specific mechanisms of the slowing down effect which are known so far in
nanomagnets.Comment: 7 page
On the contrasting spin dynamics of , and near half filling
We present simple calculations which show that incommensurability upon doping
and the width of the magnetically ordered phase in Mott-Hubbard insulators
depend strongly on the location of the hole/electron pockets in the Brillouin
zone. For systems, we found the pockets at ,
in which case the corrections to the antiferromagnetic spin stiffness grow with
doping and destroy the commensurate antiferromagnetic ordering already at a
very small doping. On the other hand, in , the hole pockets are
located at and the symmetry related points, in which case the
corrections to the stiffness scale linearly with the density of carriers and do
not destroy commensurate spin ordering. For , systems the situation is
less certain, but our results favor hole pockets at . We also
discuss briefly the tendency towards phase separation.Comment: 18 pages, LaTe
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