2,419 research outputs found
Two Cases of Primary Ectopic Ovarian Pregnancy
Primary ovarian pregnancy is one of the rarest varieties of ectopic pregnancies. Patients frequently present with abdominal pain and menstrual irregularities. Intrauterine devices have evolved as probable risk factors. Preoperative diagnosis is challenging but transvaginal sonography has often been helpful. A diagnostic delay may lead to rupture, secondary implantation or operative difficulties. Therefore, awareness of this rare condition is important in reducing the associated risks. Here, we report two cases of primary ovarian pregnancies presenting with acute abdominal pain. Transabdominal ultrasonography failed to hint at ovarian pregnancy in one, while transvaginal sonography aided in the correct diagnosis of the other. Both cases were confirmed by histopathological examinations and were successfully managed by surgery
Influence of the nature of confinement on the melting of Wigner molecules in quantum dots
We analyze the quantum melting of two-dimensional Wigner molecules (WM) in
confined geometries with distinct symmetries and compare it with corresponding
thermal melting. Our findings unfold complementary mechanisms that drive the
quantum and thermal crossovers in a WM and show that the symmetry of the
confinement plays no significant role in determining the quantum crossover
scale . This is because the zero-point motion screens the boundary effects
within short distances. The phase diagram as a function of thermal and quantum
fluctuations determined from independent criteria is unique, and shows
"melting" from the WM to both the classical and quantum "liquids." An
intriguing signature of weakening liquidity with increasing temperature, ,
is found in the extreme quantum regime. The crossover is associated with
production of defects. However, these defects appear to play distinct roles in
driving the quantum and thermal "melting." Our study will help comprehending
melting in a variety of experimental traps - from quantum dots to complex
plasma.Comment: 14 pages, 9 figure
Electrophoresis of a polyelectrolyte through a nanopore
A hydrodynamic model for determining the electrophoretic speed of a
polyelectrolyte through a nanopore is presented. It is assumed that the speed
is determined by a balance of electrical and viscous forces arising from within
the pore and that classical continuum electrostatics and hydrodynamics may be
considered applicable. An explicit formula for the translocation speed as a
function of the pore geometry and other physical parameters is obtained and is
shown to be consistent with experimental measurements on DNA translocation
through nanopores in silicon membranes. Experiments also show a weak dependence
of the translocation speed on polymer length that is not accounted for by the
present model. It is hypothesized that this is due to secondary effects that
are neglected here.Comment: 5 pages, 2 column, 2 figure
Anomaly Detection for Science DMZs Using System Performance Data
Science DMZs are specialized networks that enable large-scale distributed scientific research, providing efficient and guaranteed performance while transferring large amounts of data at high rates. The high-speed performance of a Science DMZ is made viable via data transfer nodes (DTNs), therefore they are a critical point of failure. DTNs are usually monitored with network intrusion detection systems (NIDS). However, NIDS do not consider system performance data, such as network I/O interrupts and context switches, which can also be useful in revealing anomalous system performance potentially arising due to external network based attacks or insider attacks. In this paper, we demonstrate how system performance metrics can be applied towards securing a DTN in a Science DMZ network. Specifically, we evaluate the effectiveness of system performance data in detecting TCP-SYN flood attacks on a DTN using DBSCAN (a density-based clustering algorithm) for anomaly detection. Our results demonstrate that system interrupts and context switches can be used to successfully detect TCP-SYN floods, suggesting that system performance data could be effective in detecting a variety of attacks not easily detected through network monitoring alone
Modulation of the local density of states within the -density wave theory in the underdoped cuprates
The low temperature scanning tunneling microscopy spectra in the underdoped
regime is analyzed from the perspective of coexisting -density wave and
d-wave superconducting states. The calculations are carried out in the presence
of a low concentration of unitary impurities and within the framework of the
fully self-consistent Bogoliubov-de Gennes theory, which allows local
modulations of the magnitude of the order parameters in response to the
impurities. Our theory captures the essential aspects of the experiments in the
underdoped BSCCO at very low temperatures.Comment: 4 pages, 4 eps figures, RevTex4. New added material as well as
reference
Bimaximal Neutrino Mixing in a Zee-type Model with Badly Broken Flavor Symmetry
A Zee-type neutrino mass matrix model with a badly broken horizontal symmetry
SU(3)_H is investigated. By putting a simple ansatz on the symmetry breaking
effects of SU(3)_H for transition matrix elements, it is demonstrated that the
model can give a nearly bimaximal neutrino mixing with the ratio ,
which are in excellent agreement with the observed data. In the near future,
the lepton-number violating decay will be observed.Comment: 10 pages, no figures, a comment adde
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