868 research outputs found
Symptomatic spinal cord involvement in prostate cancer
A CAJM article on prostate cancer.The literature on spinal cord involvement in prostate cancer is reviewed by searching the Medline from 1965 to 1997 and references in publications on the subject. The objective was to identify the clinical characteristics and treatment modalities of the disease.
Prostate cancer is the leading cause of metastatic spinal cord disease in men. The tumour reaches the spinal column mainly by the venous route. The frequency of involvement in decreasing order is thoracic spine, lumbar spine and cervical spine. The tumour usually exerts compression of the cord from the extradural space. However, intradural and intramedullary metastases have devastating effects. The patients have other neurological and urological symptoms prior to the onset of paraplegia. But in some, spinal cord compression may be the first symptom of prostate cancer. Plain X-rays may suffice in diagnosis but MRI is the single most valuable investigation for anatomic definition or localization of spinal cord secondaries. All forms of treatment are palliative.
Treatment options, singly or in combination, include hormonal manipulation, radiotherapy and laminectomy each often with high dose corticosteroids. Recurrence of symptoms after an initial relief with hormonal manipulation signifies escape of the tumour from endocrine control and portends a poor prognosis
A Multi-Gene Genetic Programming Application for Predicting Students Failure at School
Several efforts to predict student failure rate (SFR) at school accurately
still remains a core problem area faced by many in the educational sector. The
procedure for forecasting SFR are rigid and most often times require data
scaling or conversion into binary form such as is the case of the logistic
model which may lead to lose of information and effect size attenuation. Also,
the high number of factors, incomplete and unbalanced dataset, and black boxing
issues as in Artificial Neural Networks and Fuzzy logic systems exposes the
need for more efficient tools. Currently the application of Genetic Programming
(GP) holds great promises and has produced tremendous positive results in
different sectors. In this regard, this study developed GPSFARPS, a software
application to provide a robust solution to the prediction of SFR using an
evolutionary algorithm known as multi-gene genetic programming. The approach is
validated by feeding a testing data set to the evolved GP models. Result
obtained from GPSFARPS simulations show its unique ability to evolve a suitable
failure rate expression with a fast convergence at 30 generations from a
maximum specified generation of 500. The multi-gene system was also able to
minimize the evolved model expression and accurately predict student failure
rate using a subset of the original expressionComment: 14 pages, 9 figures, Journal paper. arXiv admin note: text overlap
with arXiv:1403.0623 by other author
Utilitarian analysis of Igbo satiric poems
Oral literature, especially oral poetry been an instrument of social control which blends or repudiates a person for doing what are regarded as contrary to the mores or laws of the society. Oral satiric poems have been good instruments for checkmating the society. This paper examined the utilitarian value of oral satiric poem to ascertain their value to the society. Three research questions were raised to guide this study. It is a descriptive study. The data was collected through oral interview, published, unpublished and recorded tapes. Seven (7) oral satiric poems were collected for easy investigation. The analysis revealed that satiric poems have social as well as cultural relevance. The study recommended that the rich cultural heritage which abounds in the Igbo satiric poems should be harnessed by compiling and documenting them to preserve them for posterity
The Impact of Monetary Policy Rate on Inflation in Nigeria
This work investigated the determinants of inflation in Nigeria using a monthly data from January 2007 to August 2014. The ordinary least square (OLS) method was adopted because of its best linear unbiased estimator (BLUE) property. The result showed that expected inflation, exchange rate and money supply influenced inflation, while annual treasury bill rate and monetary policy rate though rightly signed did not influence inflation in Nigeria within the period under investigation. The estimated model displayed that all the explanatory variables used for the analysis accounted for 90% variation in explaining the direction of inflation as regards to increase or decrease. The co-integration test showed that a long term relationship existed among the variables and they were stationary at order one I (1). Keywords: Inflation, Co-integration, Keynesian and Monetary Policy
Can Higher Inflation Lead to Currency Appreciation in Nigeria?
This work verified if higher inflation can lead to currency appreciation in Nigeria using an annual data from 1981 to 2013. The ordinary least square (OLS) method was adopted because of its best linear unbiased estimator property. The result showed that current inflation does not lead to currency appreciation in Nigeria, and rather what leads to currency appreciation is expected inflation. Although, monetary policy rate and export were significant in determining Naira value but they did not show the expected signs. The estimated model showed stability and all the explanatory variables used for the analysis accounted for 96% variation in explaining the direction of value of Naira as regards to appreciation or depreciation. The co-integration test showed that a long term relationship existed among the variables and they were stationary at order one I (1). Keywords: Currency, Inflation, Co-integration and Appreciatio
An examination of moral and value motifs in Igbo folktales and its influence on character formation of children
The art of child upbringing has been in existence from the inception of the world. The secrets required in turning out balanced and well behaved individuals have been passed down through the ages (from generation to generation) through various agencies and individuals responsible. As the society evolves through stages of change, the family which is a microcosm of the society also changes. Institutions and artifacts are shaken and re-examined, discarded or if fortunate retained and most times placed at the lower rung of the ladder in the scheme of things. This has been the fate of Igbo folktales which has been thrown out of the schedule of families especially the “modern” families. This paper therefore is of the view that folktales contain values and morals which can be a handy and useful tool for protecting the mind of the young from the negative influences that abound in the society today and inculcating the right values and morals in them. The paper established that folktales are concerned with maintaining positive relationship, tolerance and peaceful co-existence, wisdom for survival, hard work, respect, etc. The data for the study is based on a sample of Igbo folktale. The paper concludes that modern parents/families should blend/build in the age old and trusted asset of folktale into their modern technique of child upbringing in order to achieve a better result and by implication a better society
Numerical Analyses of Weakly Nonlinear Velocity-Density Coupling
We study evolution of various statistical quantities of smoothed cosmic
density and velocity fields using N-body simulations. The parameter
characterizes nonlinear coupling of
these two fields and determines behavior of bulk velocity dispersion as a
function of local density contrast.
It is found that this parameter depends strongly on the smoothing scale even
in quasi-linear regimes where the skewness parameter
is nearly constant and close to the predicted value by the second-order
perturbation theory. We also analyze weakly nonlinear effects caused by an
adaptive smoothing known as the gather approach.Comment: 22 pages, 4 figures, to appear in ApJ (558, Sep 10
A New Approach to Probing Large Scale Power with Peculiar Velocities
We propose a new strategy to probe the power spectrum on large scales using
galaxy peculiar velocities. We explore the properties of surveys that cover
only two small fields in opposing directions on the sky. Surveys of this type
have several advantages over those that attempt to cover the entire sky; in
particular, by concentrating galaxies in narrow cones these surveys are able to
achieve the density needed to measure several moments of the velocity field
with only a modest number of objects, even for surveys designed to probe scales
\gtwid 100\hmpc. We construct mock surveys with this geometry and analyze
them in terms of the three moments to which they are most sensitive. We
calculate window functions for these moments and construct a statistic
which can be used to put constraints on the power spectrum. In order to explore
the sensitivity of these surveys, we calculate the expectation values of the
moments and their associated measurement noise as a function of the survey
parameters such as density and depth and for several popular models of
structure formation. In addition, we have studied how well these kind of
surveys can distinguish between different power spectra and found that, for the
same number of objects, cone surveys are as good or better than full-sky
surveys in distinguishing between popular cosmological models. We find that a
survey with galaxy peculiar velocities with distance errors of 15% in
two cones with opening angle of could put significant
constraints on the power spectrum on scales of \hmpc, where few other
constraints exist.Comment: 15 pages, 3 figures, Some revisions and different figure. Accepted
for publication at ApJ letter
Power Spectrum of Velocity Fluctuations in the Universe
We investigate the power spectrum of velocity fluctuations in the universe,
, starting from four different measures of velocity: (1) the power
spectrum of velocity fluctuations from peculiar velocities of galaxies; (2) the
rms peculiar velocity of galaxy clusters; (3) the power spectrum of velocity
fluctuations from the power spectrum of density fluctuations in the galaxy
distribution; (4) and the bulk velocity from peculiar velocities of galaxies.
We show that measures (1) and (2) are not consistent with each other and either
the power spectrum from peculiar velocities of galaxies is overestimated or the
rms cluster peculiar velocity is underestimated. The amplitude of velocity
fluctuations derived from the galaxy distribution (measure 3) depends on the
parameter . We estimate the parameter on the basis of measures
(2) and (4). The power spectrum of velocity fluctuations from the galaxy
distribution in the Stromlo-APM redshift survey is consistent with the observed
rms cluster velocity and with the observed large-scale bulk flow when the
parameter is in the range 0.4-0.5. In this case the value of the
function at wavelength Mpc is km s
and the rms amplitude of the bulk flow at the radius Mpc is km s. The velocity dispersion of galaxy systems originates mostly
from the large-scale velocity fluctuations with wavelengths Mpc.Comment: Astrophysical Journal, Vol. 493, in press: 23 pages, uses AAS Latex,
and 14 separate postscript figure
An Evolving Entropy Floor in the Intracluster Gas?
Non-gravitational processes, such as feedback from galaxies and their active
nuclei, are believed to have injected excess entropy into the intracluster gas,
and therefore to have modified the density profiles in galaxy clusters during
their formation. Here we study a simple model for this so-called preheating
scenario, and ask (i) whether it can simultaneously explain both global X-ray
scaling relations and number counts of galaxy clusters, and (ii) whether the
amount of entropy required evolves with redshift. We adopt a baseline entropy
profile that fits recent hydrodynamic simulations, modify the hydrostatic
equilibrium condition for the gas by including approx. 20% non-thermal pressure
support, and add an entropy floor K_0 that is allowed to vary with redshift. We
find that the observed luminosity-temperature (L-T) relations of low-redshift
(z=0.05) HIFLUGCS clusters and high-redshift (z=0.8) WARPS clusters are best
simultaneously reproduced with an evolving entropy floor of
K_0(z)=341(1+z)^{-0.83}h^{-1/3} keV cm^2. If we restrict our analysis to the
subset of bright (kT > 3 keV) clusters, we find that the evolving entropy floor
can mimic a self-similar evolution in the L-T scaling relation. This degeneracy
with self-similar evolution is, however, broken when (0.5 < kT < 3 keV)
clusters are also included. The approx. 60% entropy increase we find from z=0.8
to z=0.05 is roughly consistent with that expected if the heating is provided
by the evolving global quasar population. Using the cosmological parameters
from the WMAP 3-year data with sigma_8=0.76, our best-fit model underpredicts
the number counts of the X-ray galaxy clusters compared to those derived from
the 158 deg^2 ROSAT PSPC survey. Treating sigma_8 as a free parameter, we find
a best-fit value of sigma_8=0.80+/- 0.02.Comment: 14 emulateapj pages with 9 figures, submitted to Ap
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