1,631 research outputs found
Real Space Visualization of Thermomagnetic Irreversibility within Supercooling and Superheating Spinodals in using Scanning Hall Probe Microscopy
Phase coexistence across disorder-broadened and magnetic-field-induced first
order antiferromagnetic to ferrimagnetic transition in polycrystalline
has been studied mesoscopically by Scanning Hall Probe
Microscope at 120K and up to 5 Tesla magnetic fields. We have observed
hysteresis with varying magnetic field and the evolution of coexisting
antiferromagnetic and ferrimagnetic state on mesoscopic length scale. These
studies show that the magnetic state of the system at low field depends on the
path followed to reach 120 K. The low field magnetic states are mesoscopically
different for virgin and second field increasing cycle when 120 K is reached by
warming from 5K, but are the same within measurement accuracy when the
measuring temperature of 120K is reached from 300K by cooling
Field induced magnetic transition and metastability in Co substituted
A detailed investigation of first order ferrimagnetic (FRI) to
antiferromagnetic (AFM) transition in Co (15%) doped is carried out.
These measurements demonstrate anomalous thermomagnetic irreversibility and
glass-like frozen FRI phase at low temperatures. The irreversibility arising
between the supercooling and superheating spinodals is distinguised in an
ingenious way from the irreversibility arising due to kinetic arrest. Field
annealing measurements shows reentrant FRI-AFM-FRI transition with increasing
temperature. These measurements also show that kinetic arrest band and
supercooling band are anitcorrelated i.e regions which are kinetically arrested
at higher temperature have lower supercooling temperature and vice versa.Comment: 10 pages, 8 figure
Causal and localizable quantum operations
We examine constraints on quantum operations imposed by relativistic
causality. A bipartite superoperator is said to be localizable if it can be
implemented by two parties (Alice and Bob) who share entanglement but do not
communicate; it is causal if the superoperator does not convey information from
Alice to Bob or from Bob to Alice. We characterize the general structure of
causal complete measurement superoperators, and exhibit examples that are
causal but not localizable. We construct another class of causal bipartite
superoperators that are not localizable by invoking bounds on the strength of
correlations among the parts of a quantum system. A bipartite superoperator is
said to be semilocalizable if it can be implemented with one-way quantum
communication from Alice to Bob, and it is semicausal if it conveys no
information from Bob to Alice. We show that all semicausal complete measurement
superoperators are semilocalizable, and we establish a general criterion for
semicausality. In the multipartite case, we observe that a measurement
superoperator that projects onto the eigenspaces of a stabilizer code is
localizable.Comment: 23 pages, 7 figures, REVTeX, minor changes and references adde
Collective traffic-like movement of ants on a trail: dynamical phases and phase transitions
The traffic-like collective movement of ants on a trail can be described by a
stochastic cellular automaton model. We have earlier investigated its unusual
flow-density relation by using various mean field approximations and computer
simulations. In this paper, we study the model following an alternative
approach based on the analogy with the zero range process, which is one of the
few known exactly solvable stochastic dynamical models. We show that our theory
can quantitatively account for the unusual non-monotonic dependence of the
average speed of the ants on their density for finite lattices with periodic
boundary conditions. Moreover, we argue that the model exhibits a continuous
phase transition at the critial density only in a limiting case. Furthermore,
we investigate the phase diagram of the model by replacing the periodic
boundary conditions by open boundary conditions.Comment: 8 pages, 6 figure
An improved method for statistical studies of the internal kinematics of HII regions: the case of M 83
We present the integrated Halpha emission line profile for 157 HII regions in
the central 3.4' x 3.4' of the galaxy M 83 (NGC 5236). Using the Fabry-Perot
interferometer GHaFaS, on the 4.2 m William Herschel on La Palma, we show the
importance of a good characterization of the instrumental response function for
the study of line profile shapes. The luminosity-velocity dispersion relation
is also studied, and in the log(L)-log(sigma) plane we do not find a linear
relation, but an upper envelope with equation log(L)=0.9 *log(sigma)+38.1. For
the adopted distance of 4.5 Mpc, the upper envelope appears at the luminosity
L=10^38.5 ergs, in full agreement with previous studies of other galaxies,
reinforcing the idea of using HII regions as standard candles.Comment: 13 pages, 9 figures, accepted for publication in MNRA
Adding control to arbitrary unknown quantum operations
While quantum computers promise significant advantages, the complexity of
quantum algorithms remains a major technological obstacle. We have developed
and demonstrated an architecture-independent technique that simplifies adding
control qubits to arbitrary quantum operations-a requirement in many quantum
algorithms, simulations and metrology. The technique is independent of how the
operation is done, does not require knowledge of what the operation is, and
largely separates the problems of how to implement a quantum operation in the
laboratory and how to add a control. We demonstrate an entanglement-based
version in a photonic system, realizing a range of different two-qubit gates
with high fidelity.Comment: 9 pages, 8 figure
Evaluation of Total Daily Dose and Glycemic Control for Patients Taking U-500 Regular Insulin Admitted to the Hospital
OBJECTIVE: Patients using U-500 regular insulin are severely insulin resistant, requiring high doses of insulin. It has been observed that a patient\u27s insulin requirements may dramatically decrease during hospitalization. This study sought to systematically investigate this phenomenon.
METHODS: We performed a retrospective chart review of patients with U-500 insulin outpatient regimens who were admitted to the San Antonio Military Medical Center over a 5-year period. Each patient\u27s outpatient total daily dose (TDD) of insulin was compared to the average inpatient TDD. The outpatient estimated average glucose (eAG) was calculated from the glycated hemoglobin (HbA1c) and compared to the average inpatient glucose.
RESULTS: There were 27 patients with a total of 62 separate admissions. The average age was 64.4 years, with a mean body mass index of 38.9 kg/m
CONCLUSION: U-500 insulin is prone to errors in the hospital setting, so conversion to U-100 insulin is a preferred option. Despite a significant reduction in insulin TDD, these patients had clinically similar glucose levels. Therefore, patients taking U-500 insulin as an outpatient can be converted to a U-100 basal-bolus regimen with at least a 50% reduction of their outpatient TDD.
ABBREVIATIONS: BG = blood glucose eAG = estimated average glucose HbA1c = glycated hemoglobin NPO = nil per os SPSS = Statistical Package for the Social Sciences TDD = total daily dose
TIMP3 Is Reduced in Atherosclerotic Plaques From Subjects With Type 2 Diabetes and Increased by SirT1
Atherosclerosis is accelerated in subjects with type 2 diabetes by unknown mechanisms. We identified tissue inhibitor of metalloproteinase 3 (TIMP3), the endogenous inhibitor of A disintegrin and metalloprotease domain 17 (ADAM17) and other matrix metalloproteinases (MMPs), as a gene modifier for insulin resistance and vascular inflammation in mice. We tested its association with atherosclerosis in subjects with type 2 diabetes and identified Sirtuin 1 (SirT1) as a major regulator of TIMP3 expression
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