72 research outputs found
Classical Trajectories of the Continuum States of the symmetric Scarf II potential
We apply the factorization technique developed by Kuru et. al. [Ann. Phys.
{\bf 323} (2008) 413] to obtain the exact analytical classical trajectories and
momenta of the continuum states of the non Hermitian but symmetric
Scarf II potential. In particular, we observe that the strange behaviour of the
quantum version at the spectral singularity has an interesting classical
analogue.Comment: 7 pages, 8 figure
Scattering in a varying mass PT symmetric double heterojunction
We observe that the reflection and transmission coefficients of a particle
within a double, PT symmetric heterojunction with spatially varying mass, show
interesting features, depending on the degree of non Hermiticity, although
there is no spontaneous breakdown of PT symmetry. The potential profile in the
intermediate layer is considered such that it has a non vanishing imaginary
part near the heterojunctions. Exact analytical solutions for the wave function
are obtained, and the reflection and transmission coefficients are plotted as a
function of energy, for both left as well as right incidence. As expected, the
spatial dependence on mass changes the nature of the scattering solutions
within the heterojunctions, and the space-time (PT) symmetry is responsible for
the left-right asymmetry in the reflection and transmission coefficients.
However, the non vanishing imaginary component of the potential near the
heterojunctions gives new and interesting results.Comment: 7 pages, 8 figure
Incidence, causes and feto-maternal outcomes of obstructed labour in a tertiary health care centre
Background: Obstructed labour is one of the most common preventable cause of maternal and neonatal morbidity and mortality in developing countries. This study was undertaken to assess the incidence, causes and feto-maternal outcomes of obstructed labour.Methods: This prospective study was carried out in the Department of Obstetrics and Gynaecology at Patna Medical College and Hospital, Patna, Bihar, India over a period of one year from February 2012 to February 2013. The 228 patients diagnosed to have obstructed labour were studied.Results: Out of 2556 deliveries conducted during this period, 228 cases of obstructed labour were found constituting an incidence of 8.9%. Majority of the patients were unbooked (89.47%), between 21-30 years of age (90.35%) and with parity 3 or more. The most common cause of obstructed labour was malposition (45.61%) followed by cephalopelvic disproportion (43.85%) and malpresentation (8.7%). caesarean section was the most common mode of delivery. In 21.92% of cases ruptured uterus was diagnosed pre-operatively among which, 2.63% has scar rupture and in remaining cases rupture was in unscarred uterus due to obstructed labour diagnosed intra-operatively. PPH was seen intra-operatively in 17.54% of cases and bladder trauma in 3.5% of cases. Most common post-operative complications were paralytic ileus (52.6%) followed by severe anaemia (48.2%) and infections (23.68%). Only 0.8% patients developed vesico-vaginal fistula as a late sequela of obstructed labour. The maternal mortality was 3.5% and perinatal mortality was 39%.Conclusions: In present study, the incidence of obstructed labour is very high. Good antenatal care, education of primary health care providers and traditional birth attendants on dangers of obstructed labour and the need for early referral is suggested to reduce the incidence of this condition
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