4,059 research outputs found
Privacy of a lossy bosonic memory channel
We study the security of the information transmission between two honest
parties realized through a lossy bosonic memory channel when losses are
captured by a dishonest party. We then show that entangled inputs can enhance
the private information of such a channel, which however does never overcome
that of unentangled inputs in absence of memory.Comment: RevTex file, 4 pages, 2 figure
An exact fluid model for relativistic electron beams: The many moments case
An interesting and satisfactory fluid model has been proposed in literature
for the the description of relativistic electron beams. It was obtained with 14
independent variables by imposing the entropy principle and the relativity
principle. Here the case is considered with an arbitrary number of independent
variables, still satisfying the above mentioned two principles; these lead to
conditions whose general solution is here found. We think that the results
satisfy also a certain ordering with respect to a smallness parameter
measuring the dispersion of the velocity about the mean; this
ordering generalizes that appearing in literature for the 14 moments case
Forgetfulness of continuous Markovian quantum channels
The notion of forgetfulness, used in discrete quantum memory channels, is
slightly weakened in order to be applied to the case of continuous channels.
This is done in the context of quantum memory channels with Markovian noise. As
a case study, we apply the notion of weak-forgetfulness to a bosonic memory
channel with additive noise. A suitable encoding and decoding unitary
transformation allows us to unravel the effects of the memory, hence the
channel capacities can be computed using known results from the memoryless
setting.Comment: 6 pages, 2 figures, comments are welcome. Minor corrections and
acknoledgment adde
First principles theory of fluctuations in vortex liquids and solids
Consistent perturbation theory for thermodynamical quantities in type II
superconductors in magnetic field at low temperatures is developed. It is
complementary to the existing expansion valid at high temperatures.
Magnetization and specific heat are calculated to two loop order and compare
well to existing Monte Carlo simulations and experiments.Comment: 3 .ps fig. In press Phys. Rev.
Pre-implantation mouse embryos cultured In vitro under different oxygen concentrations show altered ultrastructures
Abstract
Assisted Reproductive Technologies routinely utilize different culture media and oxygen (O2) concentrations to culture human embryos. Overall, embryos cultured under physiological O2 tension (5%) have improved development compared to embryos cultured under atmospheric O2 conditions (20%). The mechanisms responsible for this remain unclear. This study aimed to evaluate the effect of physiologic (5%) or atmospheric O2 (20%) tension on the microscopic ultrastructure of pre-implantation mouse embryos using Transmission Electron Microscopy (TEM). Embryos flushed out of the uterus after natural mating were used as the control. For use as the control, 2-cells, 4-cells, morulae, and blastocysts were flushed out of the uterus after natural fertilization. In vitro fertilization (IVF) was performed using potassium simplex optimized medium (KSOM) under different O2 tensions (5% and 20%) until the blastocyst stage. After collection, embryos were subjected to the standard preparative for light microscopy (LM) and TEM. We found that culture in vitro under 5% and 20% O2 results in an increase of vacuolated shaped mitochondria, cytoplasmic vacuolization and presence of multi-vesicular bodies at every embryonic stage. In addition, blastocysts generated by IVF under 5% and 20% O2 showed a lower content of heterochromatin, an interruption of the trophectodermal and inner cell mass cell membranes, an increased density of residual bodies, and high levels of glycogen granules in the cytoplasm. In conclusion, this study suggests that in vitro culture, particularly under atmospheric O2 tension, causes stage-specific changes in preimplantation embryo ultrastructure. In addition, atmospheric (20%) O2 is associated with increased alterations in embryonic ultrastructure; these changes may explain the reduced embryonic development of embryos cultured with 20% O2
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