2,093 research outputs found
Lorentz invariance of entanglement classes in multipartite systems
We analyze multipartite entanglement in systems of spin-1/2 particles from a
relativistic perspective. General conditions which have to be met for any
classification of multipartite entanglement to be Lorentz invariant are
derived, which contributes to a physical understanding of entanglement
classification. We show that quantum information in a relativistic setting
requires the partition of the Hilbert space into particles to be taken
seriously. Furthermore, we study exemplary cases and show how the spin and
momentum entanglement transforms relativistically in a multipartite setting.Comment: v2: 5 pages, 4 figures, minor changes to main body, journal
references update
A simplex of bound entangled multipartite qubit states
We construct a simplex for multipartite qubit states of even number n of
qubits, which has the same geometry concerning separability, mixedness, kind of
entanglement, amount of entanglement and nonlocality as the bipartite qubit
states. We derive the entanglement of the class of states which can be
described by only three real parameters with the help of a multipartite measure
for all discrete systems. We prove that the bounds on this measure are optimal
for the whole class of states and that it reveals that the states possess only
n-partite entanglement and not e.g. bipartite entanglement. We then show that
this n-partite entanglement can be increased by stochastic local operations and
classical communication to the purest maximal entangled states. However, pure
n-partite entanglement cannot be distilled, consequently all entangled states
in the simplex are n-partite bound entangled. We study also Bell inequalities
and find the same geometry as for bipartite qubits. Moreover, we show how the
(hidden) nonlocality for all n-partite bound entangled states can be revealed.Comment: 11 pages, 4 figures; 2nd version changed considerably and a detailed
derivation of the multipartite measure is include
Myocardial infarction does not affect circulating haematopoietic stem and progenitor cell self‐renewal ability in a rat model
Given the importance of peripheral blood haematopoietic stem and progenitor cells (HPCs) in post-acute regeneration after acute myocardial infarction (MI), the aim of the present study was to investigate the number and secondary replating capacity/self-renewal ability of HPCs in peripheral blood before and 2 weeks after MI. In female Lewis inbred rats (n = 9), MI was induced by ligation of the left coronary artery, and another nine underwent sham surgery, without ligation, for control purposes. Myocardial infarction was confirmed by troponin I concentrations 24 h after surgery. Peripheral blood was withdrawn and fractional shortening and ejection fraction of the left ventricle were assessed before (day 0) and 14 days after MI or sham surgery (day 14). After mononuclear cell isolation, primary and secondary functional colony-forming unit granulocyte–macrophage (CFU-GM) assays were performed in order to detect the kinetics of functional HPC colony counts and cell self- renewal ability in vitro. The CFU-GM counts and cell self-renewal ability remained unchanged (P < 0.05) in both groups at day 14, without interaction between groups. In the intervention group, higher day 0 CFU-GM counts showed a relationship to lower fractional shortening on day 14 (ρ = −0.82; P < 0.01). Myocardial infarction did not negatively affect circulating HPC self-renewal ability, which suggests a constant regenerative potential in the post-acute phase. A relationship of cardiac contractile function 14 days after MI with circulating CFU-GM counts on day 0 might imply functional colony count as a predictive factor for outcome after infarction
T lymphocytes from patients with primary biliary cirrhosis produce reduced amounts of lymphotoxin, tumor necrosis factor and interferon-gamma upon mitogen stimulation
Primary biliary cirrhosis (PBC) is considered an autoimmune disease characterized by destruction of small intrahepatic
bile ducts by lymphocytes. Altered functions of these lymphocytes might reflect an abnormal immune response leading
to tissue damage. We investigated lymphokine secretion by mitogen-stimulated T lymphocytes from the liver biopsies
of patients with PBC and for comparison also peripheral blood. In PBC, diminished synthesis of lymphotoxin (TNFP),
tumor necrosis factor (TNFa) and interferon-y (IFIVy) was found both in T-cell lines from liver tissue and in peripheral
blood. The reduction was most prominent for TNFP in early histological stages of PBC, and appeared to be a stable
phenomenon when T cells were tested after long-term tissue culture. Analysis of mRNA levels indicates a possible link
between reduced TNFP production and a defect in interleukin-2 transcription. The data suggest that diminished
lymphokine production in patients with PBC may play ;In important role in the immanopathogenesis of this disease
Thermo-visual feature fusion for object tracking using multiple spatiogram trackers
In this paper, we propose a framework that can efficiently combine features for robust tracking based on fusing the outputs of multiple spatiogram trackers. This is achieved without the exponential increase in storage and processing that other multimodal tracking approaches suffer from. The framework allows the features to be split arbitrarily between the trackers, as well as providing the flexibility to add, remove or dynamically weight features. We derive a mean-shift type algorithm for the framework that allows efficient object tracking with very low computational overhead. We especially target the fusion of thermal infrared and visible spectrum features as the most useful features for automated surveillance applications. Results are shown on multimodal video sequences clearly illustrating the benefits of combining multiple features using our framework
Measurement-based quantum computing with a spin ensemble coupled to a stripline cavity
Recently a new form of quantum memory has been proposed. The storage medium
is an ensemble of electron spins, coupled to a stripline cavity and an
ancillary readout system. Theoretical studies suggest that the system should be
capable of storing numerous qubits within the ensemble, and an experimental
proof-of-concept has already been performed. Here we show that this minimal
architecture is not limited to storage but is in fact capable of full quantum
processing by employing measurement-based entanglement. The technique appears
to be remarkably robust against the anticipated dominant error types. The key
enabling component, namely a readout technology that non-destructively
determines "are there n photons in the cavity?", has already been realised
experimentally.Comment: 17 pages, 8 figure
Orthotopic liver transplantation in human-immunodeficiency-virus-positive patients in Germany
Objectives: This summary evaluates the outcomes of orthotopic liver transplantation (OLT) of HIV-positive patients in Germany.
Methods: Retrospective chart analysis of HIV-positive patients, who had been liver-transplanted in Germany between July 1997 and July 2011.
Results: 38 transplantations were performed in 32 patients at 9 German transplant centres. The reasons for OLT were end-stage liver disease (ESLD) and/or liver failure due to hepatitis C (HCV) (n = 19), hepatitis B (HBV) (n = 10), multiple viral infections of the liver (n = 2) and Budd-Chiari-Syndrome. In July 2011 19/32 (60%) of the transplanted patients were still alive with a median survival of 61 months (IQR (interquartile range): 41-86 months). 6 patients had died in the early post-transplantation period from septicaemia (n = 4), primary graft dysfunction (n = 1), and intrathoracal hemorrhage (n = 1). Later on 7 patients had died from septicaemia (n = 2), delayed graft failure (n = 2), recurrent HCC (n = 2), and renal failure (n = 1). Recurrent HBV infection was efficiently prevented in 11/12 patients; HCV reinfection occurred in all patients and contributed considerably to the overall mortality.
Conclusions: Overall OLT is a feasible approach in HIV-infected patients with acceptable survival rates in Germany. Reinfection with HCV still remains a major clinical challenge in HIV/HCV coinfection after OLT
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