346 research outputs found
Broad Band Optical Polarimetric Study of IC 1805
We present the BVR broad band polarimetric observations of 51 stars belonging
to the young open cluster IC 1805. Along with the photometric data from the
literature we have modeled and subtracted the foreground dust contribution from
the maximum polarization (P_{max}) and colour excess (E_{B-V}). The mean value
of the P_max for intracluster medium and the foreground are found to be 5.008
+/-0.005 % and 4.865 +/-0.022 % respectively. Moreover, the mean value of the
wavelength of maximum polarization (lambda_{max}) for intracluster medium is
0.541 +/- 0.003 micro m, which is quite similar as the general interstellar
medium (ISM). The resulting intracluster dust component is found to have
negligible polarization efficiency as compared to interstellar dust. Some of
the observed stars in IC 1805 have shown the indication of intrinsic
polarization in their measurements.Comment: 8 pages, 7 figures, Accepted for publication in MNRA
Treatment of giant cell tumours of bone by radical curettage and bone cement
Background: Giant cell tumour of bone remains a difficult and challenging management problems because there are no absolute clinical radiographic or histologic parameters that accurately predict the tendency of any single lesion to recur or metastasize.Methods: We performed surgery on 12 patients of GCT with radical curettage and bone cement over a period of 5.8 years. Results were evaluated using the musculoskeletal skeletal grading system.Results: The present series consists of 12 case of GCT age ranging from 16-45 years. Painful swelling was the commonest presentation, limitation of motion was seen in 9 cases and pathological fracture was seen in 1 case. 9 of the tumour occurred around knee joint. Rare involvement of talus was seen in 1 case. Overall 9 patients had a perfect functional score of 30 points and 1 patient scored less than 20 points.Conclusions: Acrylic cement reconstruction is safe and effective procedure that provides local adjuvant therapy, the cement field defect is mechanically stable. Patient can bear weight immediately and rehabilitate quickly
Coexistence of magnetism and superconductivity in a t-J bilayer
We investigate coexistence of antiferromagnetic and superconducting
correlations in bilayered materials using a two-dimensional t-J model with
couplings across the layers using variational Monte Carlo calculations. It is
found that the underdoped regime supports a coexisting phase, beyond which the
(d-wave) superconducting state becomes stable. Further, the effects of
interplanar coupling parameters on the magnetic and superconducting
correlations as a function of hole doping are studied in details. The magnetic
correlations are found to diminish with increasing interplanar hopping away
from half filling, while the exchange across the layers strengthens interplanar
antiferromagnetic correlations both at and away from half filling. The
superconducting correlations show more interesting features where larger
interplanar hopping considerably reduces planar correlations at optimal doping,
while an opposite behaviour, i.e. stabilisation of the superconducting state is
realised in the overdoped regime, with the interplanar exchange all the while
playing a dormant role.Comment: 8 pages, 9 figures, RevTex4, Submitted to Phys. Rev.
Polarization in young open cluster NGC 6823
We present multiwavelength linear polarimetric observations of 104 stars
towards the region of young open cluster NGC 6823. The polarization towards NGC
6823 is dominated by foreground dust grains and we found the evidence for the
presence of several layers of dust towards the line of sight. The first layer
of dust is located approximately within 200 pc towards the cluster, which is
much closer to the Sun than the cluster (~ 2.1 kpc). The radial distribution of
the position angles for the member stars are found to show a systematic change
while the polarization found to reduce towards the outer parts of the cluster
and the average position angle of coronal region of the cluster is very close
to the inclination of the Galactic parallel (~ 32 degree). The size
distribution of the grains within NGC 6823 is similar to those in general
interstellar medium. The patchy distribution of foreground dust grains are
suggested to be mainly responsible for the both differential reddening and
polarization towards NGC 6823. The majority of the observed stars do not show
the evidence of intrinsic polarization in their light.Comment: 16 pages, 6 tables, 11 figures, Accepted for publication in MNRA
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