295 research outputs found
Congenital Lymphoedema, Bronchiectasis And Seizure: Case Report
A l0-year-old girl with facial anomalies, mental retardation, peripheral lymphoedema, convulsions, cerebral cortical dysgenetic changes, bronchiectasis and chronic sinusitis is presented. She had features of both yellow nail syndrome and Hennekam syndrome. We think that our case might be a new congenital lymphoedema syndrome or an
intermediate form between these syndromes. East African Medical Journal Vol. 85 (3) 2008: pp. 145-14
Spin 0 and spin 1/2 quantum relativistic particles in a constant gravitational field
The Klein-Gordon and Dirac equations in a semi-infinite lab (), in the
background metric \ds^2 = u^2(x) (-\dt^2 + \dx^2) + \dy^2 + \dz^2, are
investigated. The resulting equations are studied for the special case . It is shown that in the case of zero transverse-momentum, the square
of the energy eigenvalues of the spin-1/2 particles are less than the squares
of the corresponding eigenvalues of spin-0 particles with same masses, by an
amount of . Finally, for nonzero transverse-momentum, the energy
eigenvalues corresponding to large quantum numbers are obtained, and the
results for spin-0 and spin-1/2 particles are compared to each other.Comment: 12 pages, LaTeX 2
Dyonic Kerr-Newman black holes, complex scalar field and Cosmic Censorship
We construct a gedanken experiment, in which a weak wave packet of the
complex massive scalar field interacts with a four-parameter (mass, angular
momentum, electric and magnetic charges) Kerr-Newman black hole. We show that
this interaction cannot convert an extreme the black hole into a naked
sigularity for any black hole parameters and any generic wave packet
configuration. The analysis therefore provides support for the weak cosmic
censorship conjecture.Comment: Refined emphasis on the weak cosmic censorship conjecture,
conclusions otherwise unchanged. Also, two sections merged, literature review
updated, references added, a few typos correcte
On the exactness of the Semi-Classical Approximation for Non-Relativistic One Dimensional Propagators
For one dimensional non-relativistic quantum mechanical problems, we
investigate the conditions for all the position dependence of the propagator to
be in its phase, that is, the semi-classical approximation to be exact. For
velocity independent potentials we find that:
(i) the potential must be quadratic in space, but can have arbitrary time
dependence.
(ii) the phase may be made proportional to the classical action, and the
magnitude (``fluctuation factor'') can also be found from the classical
solution.
(iii) for the driven harmonic oscillator the fluctuation factor is
independent of the driving term.Comment: 7 pages, latex, no figures, published in journal of physics
The effect of orthodontic extraoral appliances on depression and the anxiety levels of patients and parents
Background: Psychosocial consequences and postâoperative anxiety in patients after fixed orthodontic treatment are important parameters that must be evaluated by clinicians not to effect patient and their parentâs psychosocial mood negatively.Objective: The aim of this study was to evaluate the changes in depression and anxiety levels of orthodontic patients and their parents before the extraoral appliance therapy, and at a 1âyear followâup.Materials and Methods: Patients and one of their parents responded to a series of questionnaires and evaluation scales in order to assess depression and anxiety levels. Two groups of patients and their parents were surveyed; one group that had not yet embarked on the treatment and another that had commenced extraâoral appliance therapy 1 year prior to the study.Results: The 1âyearâtreatment group scored significantly higher than the preâtreatment group on the depression scale and the traitâanxiety scale. Stateâtrait anxiety inventory scores did not differ significantly between the groups. The parents of the 1âyearâtreatment group also scored significantly higher on the Beck depression inventory than those of the preâtreatment group.Conclusion: The results of this study emphasize the need for due consideration of psychological parameters before and during treatment with extraâoral appliances, particularly with regard to depression and anxiety.Key words: Anxiety, depression, exoral appliance
Destroying black holes with test bodies
If a black hole can accrete a body whose spin or charge would send the black
hole parameters over the extremal limit, then a naked singularity would
presumably form, in violation of the cosmic censorship conjecture. We review
some previous results on testing cosmic censorship in this way using the test
body approximation, focusing mostly on the case of neutral black holes. Under
certain conditions a black hole can indeed be over-spun or over-charged in this
approximation, hence radiative and self-force effects must be taken into
account to further test cosmic censorship.Comment: Contribution to the proceedings of the First Mediterranean Conference
on Classical and Quantum Gravity (talk given by T. P. S.). Summarizes the
results of Phys. Rev. Lett. 103, 141101 (2009), arXiv:0907.4146 [gr-qc] and
considers further example
Associations between diurnal preference, sleep quality and externalizing behaviours: a behavioural genetic analysis
Background - Certain aspects of sleep co-occur with externalizing behaviours in youth, yet little is known about these associations in adults. The present study: (1) examines the associations between diurnal preference (morningness versus eveningness), sleep quality and externalizing behaviours; (2) explores the extent to which genetic and environmental influences are shared between or are unique to these phenotypes; (3) examines the extent to which genetic and environmental influences account for these associations.
Method - Questionnaires assessing diurnal preference, sleep quality and externalizing behaviours were completed by 1556 young adult twins and siblings.
Results - A preference for eveningness and poor sleep quality were associated with greater externalizing symptoms [r=0.28 (95% CI 0.23â0.33) and 0.34 (95% CI 0.28â0.39), respectively]. A total of 18% of the genetic influences on externalizing behaviours were shared with diurnal preference and sleep quality and an additional 14% were shared with sleep quality alone. Non-shared environmental influences common to the phenotypes were small (2%). The association between diurnal preference and externalizing behaviours was mostly explained by genetic influences [additive genetic influence (A)=80% (95% CI 0.56â1.01)], as was the association between sleep quality and externalizing behaviours [A=81% (95% CI 0.62â0.99)]. Non-shared environmental (E) influences accounted for the remaining variance for both associations [E=20% (95% CI â0.01 to 0.44) and 19% (95% CI 0.01â0.38), respectively].
Conclusions - A preference for eveningness and poor sleep quality are moderately associated with externalizing behaviours in young adults. There is a moderate amount of shared genetic influences between the phenotypes and genetic influences account for a large proportion of the association between sleep and externalizing behaviours. Further research could focus on identifying specific genetic polymorphisms common to both sleep and externalizing behaviours
The Dirac Equation Is Separable On The Dyon Black Hole Metric
Using the tetrad formalism, we carry out the separation of variables for the
massive complex Dirac equation in the gravitational and electromagnetic field
of a four-parameter (mass, angular momentum, electric and magnetic charges)
black hole.Comment: 13 page
Effect of testosterone propionate on hippocampal pyramidal neuron number in female rats
INTRODUCTION The hippocampus is an important region of the brain that regulates cognitive and emotional functions. In this study, we examined the impact of perinatal administration of testosterone propionate (TP) on the number of pyramidal neurons in the CA1 and CA3 regions of the hippocampi of female rats. METHODS Five groups of rats were used in this study. Three groups of female rats were administered TP in either both the prenatal and the postnatal periods (Group 1), only the prenatal period (Group 2) or only the postnatal period (Group 3). The other two groups of rats included control females (Group 4) and control males (Group 5). The rats were sacrificed on postnatal Day 120 and their brains were analysed for hippocampal pyramidal neuron number using stereological methods. RESULTS Control male rats (Group 5; p = 0.043) and TP-treated female rats in Groups 1 (p = 0.012) and 2 (p = 0.037), but not Group 3 (p > 0.05), had a significantly higher number of pyramidal neurons than control female rats (Group 4). The rats in Group 1 had the highest number of pyramidal neurons among the female rats. CONCLUSION Perinatal TP treatment has an augmenting effect on the number of pyramidal neurons in the hippocampi of female rats. We also found gender-based differences in the hippocampi of male and female rats, with a higher number of pyramidal neurons seen in male rats. Continuous TP administration during the prenatal and postnatal periods is more effective than administration only in the prenatal or postnatal period
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