51 research outputs found
Emerging Role for the PERK/eIF2α/ATF4 in Human Cutaneous Leishmaniasis.
Leishmania parasites utilize adaptive evasion mechanisms in infected macrophages to overcome host defenses and proliferate. We report here that the PERK/eIF2α/ATF4 signaling branch of the integrated endoplasmic reticulum stress response (IERSR) is activated by Leishmania and this pathway is important for Leishmania amazonensis infection. Knocking down PERK or ATF4 expression or inhibiting PERK kinase activity diminished L. amazonensis infection. Knocking down ATF4 decreased NRF2 expression and its nuclear translocation, reduced HO-1 expression and increased nitric oxide production. Meanwhile, the increased expression of ATF4 and HO-1 mRNAs were observed in lesions derived from patients infected with the prevalent related species L.(V.) braziliensis. Our data demonstrates that Leishmania parasites activate the PERK/eIF2α/ATF-4 pathway in cultured macrophages and infected human tissue and that this pathway is important for parasite survival and progression of the infection
Geometric Entanglement of Symmetric States and the Majorana Representation
Permutation-symmetric quantum states appear in a variety of physical
situations, and they have been proposed for quantum information tasks. This
article builds upon the results of [New J. Phys. 12, 073025 (2010)], where the
maximally entangled symmetric states of up to twelve qubits were explored, and
their amount of geometric entanglement determined by numeric and analytic
means. For this the Majorana representation, a generalization of the Bloch
sphere representation, can be employed to represent symmetric n qubit states by
n points on the surface of a unit sphere. Symmetries of this point distribution
simplify the determination of the entanglement, and enable the study of quantum
states in novel ways. Here it is shown that the duality relationship of
Platonic solids has a counterpart in the Majorana representation, and that in
general maximally entangled symmetric states neither correspond to anticoherent
spin states nor to spherical designs. The usability of symmetric states as
resources for measurement-based quantum computing is also discussed.Comment: 10 pages, 8 figures; submitted to Lecture Notes in Computer Science
(LNCS
Dynamics of multipartite quantum correlations under decoherence
Quantum discord is an optimal resource for the quantification of classical
and non-classical correlations as compared to other related measures. Geometric
measure of quantum discord is another measure of quantum correlations.
Recently, the geometric quantum discord for multipartite states has been
introduced by Jianwei Xu [arxiv:quant/ph.1205.0330]. Motivated from the recent
study [Ann. Phys. 327 (2012) 851] for the bipartite systems, I have
investigated global quantum discord (QD) and geometric quantum discord (GQD)
under the influence of external environments for different multipartite states.
Werner-GHZ type three-qubit and six-qubit states are considered in inertial and
non-inertial settings. The dynamics of QD and GQD is investigated under
amplitude damping, phase damping, depolarizing and flipping channels. It is
seen that the quantum discord vanishes for p>0.75 in case of three-qubit GHZ
states and for p>0.5 for six qubit GHZ states. This implies that multipartite
states are more fragile to decoherence for higher values of N. Surprisingly, a
rapid sudden death of discord occurs in case of phase flip channel. However,
for bit flip channel, no sudden death happens for the six-qubit states. On the
other hand, depolarizing channel heavily influences the QD and GQD as compared
to the amplitude damping channel. It means that the depolarizing channel has
the most destructive influence on the discords for multipartite states. From
the perspective of accelerated observers, it is seen that effect of environment
on QD and GQD is much stronger than that of the acceleration of non-inertial
frames. The degradation of QD and GQD happens due to Unruh effect. Furthermore,
QD exhibits more robustness than GQD when the multipartite systems are exposed
to environment.Comment: 15 pages, 4 figures, 4 table
Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in âs = 7 TeV pp collisions with the ATLAS detector
A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fbâ1 of protonâproton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC
Measurements of inclusive jet suppression in heavy ion collisions at the LHC
provide direct sensitivity to the physics of jet quenching. In a sample of
lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated
luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with
a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the
transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the
anti-kt algorithm with values for the distance parameter that determines the
nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of
the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp.
Jet production is found to be suppressed by approximately a factor of two in
the 10% most central collisions relative to peripheral collisions. Rcp varies
smoothly with centrality as characterized by the number of participating
nucleons. The observed suppression is only weakly dependent on jet radius and
transverse momentum. These results provide the first direct measurement of
inclusive jet suppression in heavy ion collisions and complement previous
measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables,
submitted to Physics Letters B. All figures including auxiliary figures are
available at
http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02
NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics
Xenarthrans â anteaters, sloths, and armadillos â have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset
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