1,183 research outputs found
Structural Phase Transitions of the Metal Oxide Perovskites SrTiO3, LaAlO3 and LaTiO3 Studied with a Screened Hybrid Functional
We have investigated the structural phase transitions of the transition metal
oxide perovskites SrTiO, LaAlO and LaTiO using the screened
hybrid density functional of Heyd, Scuseria and Ernzerhof (HSE06). We show that
HSE06-computed lattice parameters, octahedral tilts and rotations, as well as
electronic properties, are significantly improved over semilocal functionals.
We predict the crystal field splitting () resulting from the
structural phase transition in SrTiO and LaAlO to be 3 meV and 10
meV, respectively, in excellent agreement with experimental results. HSE06
identifies correctly LaTiO in the magnetic sates as a Mott insulator.
Also, it predicts that the GdFeO-type distortion in non-magnetic
LaTiO will induce a large of 410 meV. This large
crystal-field splitting associated with the large magnetic moment found in the
G-type antiferromagnetic state suggest that LaTiO has an induced orbital
order, which is confirmed by the visualisation of the highest occupied
orbitals. These results strongly indicate that HSE06 is capable of efficiently
and accurately modeling perovskite oxides, and promises to efficiently capture
the physics at their heterointerfaces
Phosphoregulation on mitochondria: Integration of cell and organelle responses
Mitochondria are highly integrated organelles that are crucial to cell adaptation and mitigating adverse physiology. Recent studies demonstrate that fundamental signal transduction pathways incorporate mitochondrial substrates into their biological programs. Reversible phosphorylation is emerging as a useful mechanism to modulate mitochondrial function in accordance with cellular changes. Critical serine/threonine protein kinases, such as the c‐Jun N‐terminal kinase (JNK), protein kinase A (PKA), PTEN‐induced kinase‐1 (PINK1), and AMP‐dependent protein kinase (AMPK), readily translocate to the outer mitochondrial membrane (OMM), the interface of mitochondria‐cell communication. OMM protein kinases phosphorylate diverse mitochondrial substrates that have discrete effects on organelle dynamics, protein import, respiratory complex activity, antioxidant capacity, and apoptosis. OMM phosphorylation events can be tempered through the actions of local protein phosphatases, such as mitogen‐activated protein kinase phosphatase‐1 (MKP‐1) and protein phosphatase 2A (PP2A), to regulate the extent and duration of signaling. The central mediators of OMM signal transduction are the scaffold proteins because the relative abundance of these accessory proteins determines the magnitude and duration of a signaling event on the mitochondrial surface, which dictates the biological outcome of a local signal transduction pathway. The concentrations of scaffold proteins, such as A‐kinase anchoring proteins (AKAPs) and Sab (or SH3 binding protein 5—SH3BP5), have been shown to influence neuronal survival and vulnerability, respectively, in models of Parkinson\u27s disease (PD), highlighting the importance of OMM signaling to health and disease. Despite recent progress, much remains to be discovered concerning the mechanisms of OMM signaling. Nonetheless, enhancing beneficial OMM signaling events and inhibiting detrimental protein‐protein interactions on the mitochondrial surface may represent highly selective approaches to restore mitochondrial health and homeostasis and mitigate organelle dysfunction in conditions such as PD
Weather, Crime, and Mental Illness
ABSTRACT - A simple count of disturbed incidents in the mentally ill and total radio transmissions of the Minneapolis Police Departmenf were collected daily over a six-month period. These were correlated with calendar time, temperature, humidity, and barometric pressure for the same period. Separate comparisons were made of all these measures for December 1959 with those of other Decembers. All the weather variables correlated linearly and significantly with the behavior v.ariables; temperature and humidity, positively; barometric pressure negatively. Calendar time for the half year correlated linearly and negatively. December 1959 had a higher crime and mental disturbance rate than other Decembers; this was accompanied by higher temperature and humidity
A Re-evaluation of the “Oncogenic” Nature of Wnt/β-catenin Signaling in Melanoma and Other Cancers
In cancer, Wnt/β-catenin signaling is ubiquitously referred to as an “oncogenic” pathway that promotes tumor progression. This review examines how the regulation and downstream effects of Wnt/β-catenin signaling in cancer varies depending on cellular context, with a focus on malignant melanoma. We emphasize that the cellular homeostasis of Wnt/β-catenin signaling may represent a more appropriate concept than the simplified view of the Wnt/β-catenin pathway as either oncogenic or tumor-suppressing. Ultimately, a more refined understanding of the contextual regulation of Wnt/β-catenin signaling will be essential for addressing if and how therapeutic targeting of this pathway could be leveraged for patient benefit
Generation of Three-Qubit Entangled States using Superconducting Phase Qubits
Entanglement is one of the key resources required for quantum computation, so
experimentally creating and measuring entangled states is of crucial importance
in the various physical implementations of a quantum computer. In
superconducting qubits, two-qubit entangled states have been demonstrated and
used to show violations of Bell's Inequality and to implement simple quantum
algorithms. Unlike the two-qubit case, however, where all maximally-entangled
two-qubit states are equivalent up to local changes of basis, three qubits can
be entangled in two fundamentally different ways, typified by the states
and . Here we demonstrate the operation of three coupled
superconducting phase qubits and use them to create and measure
and states. The states are fully characterized
using quantum state tomography and are shown to satisfy entanglement witnesses,
confirming that they are indeed examples of three-qubit entanglement and are
not separable into mixtures of two-qubit entanglement.Comment: 9 pages, 5 figures. Version 2: added supplementary information and
fixed image distortion in Figure 2
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Degradation of the materials of construction in Li-ion batteries
The primary current-collector materials being used in lithium-ion cells are susceptible to environmental degradation: aluminum to pitting corrosion and copper to environmentally assisted cracking. Pitting occurs at the highly oxidizing potentials associated with the positive-electrode charge condition. However, the pitting mechanism is more complex than that typically observed in aqueous systems in that the pits are filled with a mixed metal/oxide product and exist as mounds or nodules on the surface. Electrochemical impedance spectroscopy was shown to be an effective analytical tool for quantifying and verifying aluminum corrosion behavior. Two fluorocarbon-based coatings were shown to improve the resistance of Al to pitting attack. Detailed x-ray photoelectron spectroscopy (XPS) surface analyses showed that there was very little difference in the films observed after simple immersion in either PC:DEC or EC:DMC electrolytes versus those following electrical cycling. Li and P are the predominant surface species. Finally, environmental cracking of copper can occur at or near the lithium potential and only if specific metallurgical conditions exist (work-hardening and large grain size)
Holistic Slowdown Driven Scheduling and Resource Management for Malleable Jobs
In job scheduling, the concept of malleability has been explored since many
years ago. Research shows that malleability improves system performance, but
its utilization in HPC never became widespread. The causes are the difficulty
in developing malleable applications, and the lack of support and integration
of the different layers of the HPC software stack. However, in the last years,
malleability in job scheduling is becoming more critical because of the
increasing complexity of hardware and workloads. In this context, using nodes
in an exclusive mode is not always the most efficient solution as in
traditional HPC jobs, where applications were highly tuned for static
allocations, but offering zero flexibility to dynamic executions. This paper
proposes a new holistic, dynamic job scheduling policy, Slowdown Driven
(SD-Policy), which exploits the malleability of applications as the key
technology to reduce the average slowdown and response time of jobs. SD-Policy
is based on backfill and node sharing. It applies malleability to running jobs
to make room for jobs that will run with a reduced set of resources, only when
the estimated slowdown improves over the static approach. We implemented
SD-Policy in SLURM and evaluated it in a real production environment, and with
a simulator using workloads of up to 198K jobs. Results show better resource
utilization with the reduction of makespan, response time, slowdown, and energy
consumption, up to respectively 7%, 50%, 70%, and 6%, for the evaluated
workloads
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Corrosion of current-collector materials in Li-ion cells
The primary current-collector materials being used in lithium-ion cells are susceptible to environmental degradation: aluminum to pitting corrosion and copper to environmentally assisted cracking. Pitting occurs at the highly oxidizing potentials associated with the positive-electrode charge condition. However, the pitting mechanism is more complex than that typically observed in aqueous systems in that the pits are filled with a mixed metal/oxide product and exist as mounds or nodules on the surface. Electrochemical impedance was shown to be an effective analytical tool for quantification and verification of visual observations and trends. Two fluorocarbon-based coatings were shown to improve the resistance of Al to localized pitting. Finally, environmental cracking of copper can occur at or near the lithium potential and only if specific metallurgical conditions exist (work hardening and large grain size)
CHILES: HI morphology and galaxy environment at z=0.12 and z=0.17
We present a study of 16 HI-detected galaxies found in 178 hours of
observations from Epoch 1 of the COSMOS HI Large Extragalactic Survey (CHILES).
We focus on two redshift ranges between 0.108 <= z <= 0.127 and 0.162 <= z <=
0.183 which are among the worst affected by radio frequency interference (RFI).
While this represents only 10% of the total frequency coverage and 18% of the
total expected time on source compared to what will be the full CHILES survey,
we demonstrate that our data reduction pipeline recovers high quality data even
in regions severely impacted by RFI. We report on our in-depth testing of an
automated spectral line source finder to produce HI total intensity maps which
we present side-by-side with significance maps to evaluate the reliability of
the morphology recovered by the source finder. We recommend that this become a
common place manner of presenting data from upcoming HI surveys of resolved
objects. We use the COSMOS 20k group catalogue, and we extract filamentary
structure using the topological DisPerSE algorithm to evaluate the \hi\
morphology in the context of both local and large-scale environments and we
discuss the shortcomings of both methods. Many of the detections show disturbed
HI morphologies suggesting they have undergone a recent interaction which is
not evident from deep optical imaging alone. Overall, the sample showcases the
broad range of ways in which galaxies interact with their environment. This is
a first look at the population of galaxies and their local and large-scale
environments observed in HI by CHILES at redshifts beyond the z=0.1 Universe.Comment: 23 pages, 12 figures, 1 interactive 3D figure, accepted to MNRA
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