1,660 research outputs found
Nonperturbative solution of the Nonconfining Schwinger Model with a generalized regularization
Nonconfining Schwinger Model [AR] is studied with a one parameter class of
kinetic energy like regularization. It may be thought of as a generalization
over the regularization considered in [AR]. Phasespace structure has been
determined in this new situation. The mass of the gauge boson acquires a
generalized expression with the bare coupling constant and the parameters
involved in the regularization. Deconfinement scenario has become transparent
at the quark-antiquark potential level.Comment: 13 pages latex fil
Perforation of the appendix and the sigmoid colon by an ectopic IUD
The perforation of both appendix and sigmoid colon by an ectopic Intrauterine device (IUD) by an intrauterine device is a rare occurrence. We present a case of a patient is a 47- year- old hispanic woman who presented at the Gynaecology clinic with complaints of chronic right sided pelvic pain. She had an intrauterine device inserted 10 years prior with no recent gynaecological follow-up. The device was identified by ultrasonography and she was planned for a hysterectomy and IUD retrieval by the gynaecology team. An intra-operative finding of sigmoid colon and appendiceal perforation by an IUD during a total abdominal hysterectomy and emergent involvement of the general surgery team. She underwent a segmental resection of the involved sigmoid colon, appendectomy and removal of the IUD. All missing Intrauterine devices should be accurately localized by tomographic or magnetic imaging preoperatively
Thin-shell wormholes from black holes with dilaton and monopole fields
We provide a new type of thin-shell wormhole from the black holes with
dilaton and monopole fields. The dilaton and monopole that built the black
holes may supply fuel to construct the wormholes. Several characteristics of
this thin-shell wormhole have been discussed. Finally, we discuss the stability
of the thin-shell wormholes with a "phantom-like" equation of state for the
exotic matter at the throat.Comment: 6 pages and 3 figures, some typos are corrected and accepted in
Int.J.Theor.Phy
Cu-based metalorganic systems: an ab initio study of the electronic structure
Within a first principles framework, we study the electronic structure of the
recently synthesized polymeric coordination compound
Cu(II)-2,5-bis(pyrazol-1-yl)-1,4-dihydroxybenzene (CuCCP), which has been
suggested to be a good realization of a Heisenberg spin-1/2 chain with
antiferromagnetic coupling. By using a combination of classical with ab initio
quantum mechanical methods, we design on the computer reliable modified
structures of CuCCP aimed at studying effects of Cu-Cu coupling strength
variations on this spin-1/2 system. For this purpose, we performed two types of
modifications on CuCCP. In one case, we replaced H in the linker by i) an
electron donating group (NH2) and ii) an electron withdrawing group (CN), while
the other modification consisted in adding H2O and NH3 molecules in the
structure which change the local coordination of the Cu(II) ions. With the
NMTO-downfolding method we provide a quantitative analysis of the modified
electronic structure and the nature of the Cu-Cu interaction paths in these new
structures and discuss its implications for the underlying microscopic model.Comment: 18 pages, 11 figures, final versio
Magnetic properties of PdAs2O6: a dilute spin system with an unusually high N\'eel temperature
The crystal structure and magnetic ordering pattern of PdAs2O6 were
investigated by neutron powder diffraction. While the magnetic structure of
PdAs2O6 is identical to the one of its isostructural 3d-homologue NiAs2O6, its
N\'{e}el temperature (140 K) is much higher than the one of NiAs2O6 (30 K).
This is surprising in view of the long distance and indirect exchange path
between the magnetic Pd ions. Density functional calculations yield
insight into the electronic structure and the geometry of the exchange-bond
network of both PdAs2O6 and NiAs2O6, and provide a semi-quantitative
explanation of the large amplitude difference between their primary exchange
interaction parameters
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