13,039 research outputs found
The Higgsino-Singlino World at the Large Hadron Collider
We consider light higgsinos and singlinos in the next-to-minimal
supersymmetric Standard Model at the Large Hadron Collider. We assume that the
singlino is the lightest supersymmetric particle and that the higgsino is the
next-to-lightest supersymmetric particle with the remaining supersymmetric
particles in the multi-TeV range. This scenario, which is motivated by the
flavor and CP issues, provides a phenomenologically viable dark matter
candidate and improved electroweak fit consistent with the measured Higgs mass.
Here, the higgsinos decay into on (off)-shell gauge boson and the singlino. We
consider the leptonic decay modes and the resulting signature is three isolated
leptons and missing transverse energy which is known as the trilepton signal.
We simulate the signal and the Standard Model backgrounds and present the
exclusion region in the higgsino-singlino mass plane at the Large Hadron
Collider at TeV for an integrated luminosity of 300 fb.Comment: 12 pages, overall changes, conclusion unchanged, matches published
versio
Pretzel links, mutation, and the slice-ribbon conjecture
Let p and q be distinct integers greater than one. We show that the
2-component pretzel link P(p,q,-p,-q) is not slice, even though it has a ribbon
mutant, by using 3-fold branched covers and an obstruction based on Donaldson's
diagonalization theorem. As a consequence, we prove the slice-ribbon conjecture
for 4-stranded 2-component pretzel links.Comment: 14 pages, 7 figures, V2: Implements suggestions from a referee
report. This version has been accepted for publication by MR
Detecting non-decomposability of time evolution via extreme gain of correlations
Non-commutativity is one of the most elementary non-classical features of
quantum observables. Here we propose a method to detect non-commutativity of
interaction Hamiltonians of two probe objects coupled via a mediator. If these
objects are open to their local environments, our method reveals
non-decomposability of temporal evolution into a sequence of interactions
between each probe and the mediator. The Hamiltonians or Lindblad operators can
remain unknown throughout the assessment, we only require knowledge of the
dimension of the mediator. Furthermore, no operations on the mediator are
necessary. Technically, under the assumption of decomposable evolution, we
derive upper bounds on correlations between the probes and then demonstrate
that these bounds can be violated with correlation dynamics generated by
non-commuting Hamiltonians, e.g., Jaynes-Cummings coupling. An intuitive
explanation is provided in terms of multiple exchanges of a virtual particle
which lead to the excessive accumulation of correlations. A plethora of
correlation quantifiers are helpful in our method, e.g., quantum entanglement,
discord, mutual information, and even classical correlation. Finally, we
discuss exemplary applications of the method in quantum information: the
distribution of correlations and witnessing dimension of an object.Comment: 7 pages, 2 figure
Facile and time-resolved chemical growth of nanoporous CaxCoO2 thin films for flexible and thermoelectric applications
CaxCoO2 thin films can be promising for widespread flexible thermoelectric
applications in a wide temperature range from room-temperature self-powered
wearable applications (by harvesting power from body heat) to energy harvesting
from hot surfaces (e.g., hot pipes) if a cost-effective and facile growth
technique is developed. Here, we demonstrate a time resolved, facile and
ligand-free soft chemical method for the growth of nanoporous Ca0.35CoO2 thin
films on sapphire and mica substrates from a water-based precursor ink,
composed of in-situ prepared Ca2+-DMF and Co2+-DMF complexes. Mica serves as
flexible substrate as well as sacrificial layer for film transfer. The grown
films are oriented and can sustain bending stress until a bending radius of 15
mm. Despite the presence of nanopores, the power factor of Ca0.35CoO2 film is
found to be as high as 0.50 x 10-4 Wm-1K-2 near room temperature. The present
technique, being simple and fast to be potentially suitable for cost-effective
industrial upscaling.Comment: 16 pages, 5 figure
Role of microenvironment in the mixed Langmuir-Blodgett films
This paper reports the pi-A isotherms and spectroscopic characteristics of
mixed Langmuir and Langmuir-Blodgett (LB) films of non-amphiphilic carbazole
(CA) molecules mixed with polymethyl methacrylate (PMMA) and stearic acid (SA).
pi-A isotherm studies of mixed monolayer and as well as also the collapse
pressure study of isotherms definitely conclude that CA is incorporated into
PMMA and SA matrices. However CA is stacked in the PMMA/SA chains and forms
microcrystalline aggregates as is evidenced from the scanning electron
micrograph picture. Nature of these aggregated species in the mixed LB films
has been revealed by UV-Vis absorption and fluorescence spectroscopic studies.
The presence of two different kinds of band systems in the fluorescence spectra
of the mixed LB films have been observed. This may be due to the formation of
low dimensional aggregates in the mixed LB films. Intensity distribution of
different band system is highly sensitive to the microenvironment of two
different matrices as well as also on the film thicknessComment: 11 pages, 5 figure
Esophageal perforation following anterior cervical spine surgery: Case report and review of the literature
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Mammalian EAK-7 activates alternative mTOR signaling to regulate cell proliferation and migration.
Nematode EAK-7 (enhancer-of-akt-1-7) regulates dauer formation and controls life span; however, the function of the human ortholog mammalian EAK-7 (mEAK-7) is unknown. We report that mEAK-7 activates an alternative mechanistic/mammalian target of rapamycin (mTOR) signaling pathway in human cells, in which mEAK-7 interacts with mTOR at the lysosome to facilitate S6K2 activation and 4E-BP1 repression. Despite interacting with mTOR and mammalian lethal with SEC13 protein 8 (mLST8), mEAK-7 does not interact with other mTOR complex 1 (mTORC1) or mTOR complex 2 (mTORC2) components; however, it is essential for mTOR signaling at the lysosome. This phenomenon is distinguished by S6 and 4E-BP1 activity in response to nutrient stimulation. Conventional S6K1 phosphorylation is uncoupled from S6 phosphorylation in response to mEAK-7 knockdown. mEAK-7 recruits mTOR to the lysosome, a crucial compartment for mTOR activation. Loss of mEAK-7 results in a marked decrease in lysosomal localization of mTOR, whereas overexpression of mEAK-7 results in enhanced lysosomal localization of mTOR. Deletion of the carboxyl terminus of mEAK-7 significantly decreases mTOR interaction. mEAK-7 knockdown decreases cell proliferation and migration, whereas overexpression of mEAK-7 enhances these cellular effects. Constitutively activated S6K rescues mTOR signaling in mEAK-7-knocked down cells. Thus, mEAK-7 activates an alternative mTOR signaling pathway through S6K2 and 4E-BP1 to regulate cell proliferation and migration
The 2HA line of Medicago truncatula has characteristics of an epigenetic mutant that is weakly ethylene insensitive
BACKGROUND The Medicago truncatula 2HA seed line is highly embryogenic while the parental line Jemalong rarely produces embryos. The 2HA line was developed from one of the rare Jemalong regenerates and this method for obtaining a highly regenerable genotype in M. truncatula is readily reproducible suggesting an epigenetic mechanism. Microarray transcriptomic analysis showed down regulation of an ETHYLENE INSENSITIVE 3-like gene in 2HA callus which provided an approach to investigating epigenetic regulation of genes related to ethylene signalling and the 2HA phenotype. Ethylene is involved in many developmental processes including somatic embryogenesis (SE) and is associated with stress responses. RESULTS Microarray transcriptomic analysis showed a significant number of up-regulated transcripts in 2HA tissue culture, including nodule and embryo specific genes and transposon-like genes, while only a few genes were down-regulated, including an EIN3-like gene we called MtEIL1. This reduced expression was associated with ethylene insensitivity of 2HA plants that was further investigated. The weak ethylene insensitivity affected root and nodule development. Sequencing of MtEIL1 found no difference between 2HA and wild-type plants. DNA methylation analysis of MtEIL1 revealed significant difference between 2HA and wild-type plants. Tiling arrays demonstrated an elevated level of miRNA in 2HA plants that hybridised to the antisense strand of the MtEIL1 gene. AFLP-like methylation profiling revealed more differences in DNA methylation between 2HA and wild-type. Segregation analysis demonstrated the recessive nature of the eil1 phenotype and the dominant nature of the SE trait. CONCLUSIONS We have demonstrated that EIL1 of Medicago truncatula (MtEIL1) is epigenetically silenced in the 2HA seed line. The possible cause is an elevated level of miRNA that targets its 3'UTR and is also associated with DNA methylation of MtEIL1. Down regulation of MtEIL1 makes it possible to form nodules in the presence of ethylene and affects root growth under normal conditions. Segregation analysis showed no association between MtEIL1 expression and SE in culture but the role and mechanism of ethylene signalling in the process of plant regeneration through SE requires further investigation. The work also suggests that epigenetic changes to a particular gene induced in culture can be fixed in regenerated plants.This work was funded by the Australian Research Council (CEO348212) through the ARC Centre of Excellence for Integrative Legume Research (CILR)
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mEAK-7 Forms an Alternative mTOR Complex with DNA-PKcs in Human Cancer.
MTOR associated protein, eak-7 homolog (mEAK-7), activates mechanistic target of rapamycin (mTOR) signaling in human cells through an alternative mTOR complex to regulate S6K2 and 4E-BP1. However, the role of mEAK-7 in human cancer has not yet been identified. We demonstrate that mEAK-7 and mTOR signaling are strongly elevated in tumor and metastatic lymph nodes of patients with non-small-cell lung carcinoma compared with those of patients with normal lung or lymph tissue. Cancer stem cells, CD44+/CD90+ cells, yield elevated mEAK-7 and activated mTOR signaling. mEAK-7 is required for clonogenic potential and spheroid formation. mEAK-7 associates with DNA-dependent protein kinase catalytic subunit isoform 1 (DNA-PKcs), and this interaction is increased in response to X-ray irradiation to regulate S6K2 signaling. DNA-PKcs pharmacologic inhibition or genetic knockout reduced S6K2, mEAK-7, and mTOR binding with DNA-PKcs, resulting in loss of S6K2 activity and mTOR signaling. Therefore, mEAK-7 forms an alternative mTOR complex with DNA-PKcs to regulate S6K2 in human cancer cells
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