4,920 research outputs found
Double resonance in the infinite-range quantum Ising model
We study quantum resonance behavior of the infinite-range kinetic Ising model
at zero temperature. Numerical integration of the time-dependent Schr\"odinger
equation in the presence of an external magnetic field in the direction is
performed at various transverse field strengths . It is revealed that two
resonance peaks occur when the energy gap matches the external driving
frequency at two distinct values of , one below and the other above the
quantum phase transition. From the similar observations already made in
classical systems with phase transitions, we propose that the double resonance
peaks should be a generic feature of continuous transitions, for both quantum
and classical many-body systems.Comment: 4 pages, 5 figure
Superconductivity-induced Phonon Renormalization on NaFeCoAs
We report a study of the lattice dynamics in superconducting NaFeAs (Tc = 8
K) and doped NaFe0.97Co0.03As (Tc = 20 K) using Raman light scattering. Five of
the six phonon modes expected from group theory are observed. In contrast with
results obtained on iso-structural and iso-electronic LiFeAs, anomalous
broadening of Eg(As) and A1g(Na) modes upon cooling is observed in both
samples. In addition, in the Co-doped sample, a superconductivity-induced
renormalization of the frequency and linewidth of the B1g(Fe) vibration is
observed. This renormalization can not be understood within a single band and
simple multi-band approaches. A theoretical model that includes the effects of
SDW correlations along with sign-changing s-wave pairing state and interband
scattering has been developed to explain the observed behavior of the B1g(Fe)
mode.Comment: 10 pages; 6 figure
Phonon arithmetic in a trapped ion system
Single-quantum level operations are important tools to manipulate a quantum state. Annihilation or creation of single particles translates a quantum state to another by adding or subtracting a particle, depending on how many are already in the given state. The operations are probabilistic and the success rate has yet been low in their experimental realization. Here we experimentally demonstrate (near) deterministic addition and subtraction of a bosonic particle, in particular a phonon of ionic motion in a harmonic potential. We realize the operations by coupling phonons to an auxiliary two-level system and applying transitionless adiabatic passage. We show handy repetition of the operations on various initial states and demonstrate by the reconstruction of the density matrices that the operations preserve coherences. We observe the transformation of a classical state to a highly non-classical one and a Gaussian state to a non-Gaussian one by applying a sequence of operations deterministically
Effect of betaine and ascorbic acid in drinking water on growth performance and blood biomarkers in meat ducks exposed to heat stress
The aim of this study was to compare the effect of drinking water that contains various levels of ascorbic acid (AA) and betaine (BT) on growth performance and blood biomarkers in meat ducks exposed to heat stress. Six hundred and forty one-day-old Cherry Valley ducks were randomly assigned to one of seven treatment groups: i) control group, drinking water without ascorbic acid or betaine, ii) AA100, drinking water containing ascorbic acid at 100 milligrams per litre, iii) AA200, drinking water containing ascorbic acid at 200 milligrams per litre, iv) AA300, drinking water containing ascorbic acid at 300 milligrams per litre, v) BT400, drinking water containing betaine at 400 milligrams per litre, vi) BT800, drinking water containing betaine at 800 milligrams per litre, and vii) BT1200, drinking water containing betaine at 1200 milligrams per litre. The ducks were exposed to heat stress (11:00 to 17:00, 33 °C to 43 °C, relative humidity 70%, artificially controlled-environment houses) from the 22nd to 42nd days. Ducks from treatment groups AA300 and BT1200 displayed significantly increased bodyweight gains compared with those in the control group. Blood levels of glucose, and activities of aspartate aminotransferase and alanine aminotransferase in all treatment groups were significantly lower than those observed in the control group. Red blood cell count, platelet number, electrolytes and blood gas concentrations were significantly higher in all treatment groups compared with those in the control group. Blood pH levels in all treatment groups were lower than those in the control group. In conclusion, drinking water containing ascorbic acid or betaine improved the growth performance via biomarker homeostasis in blood of meat ducks exposed to heat stress.Keywords: body weight gain, blood lipid, red blood cell, electrolytes; blood gas, blood p
Quantum state conversion by cross-Kerr interaction
A generalized Mach-Zehnder-type interferometer equipped with cross-Kerr
elements is proposed to convert N-photon truncated single-mode quantum states
into (N+1)-mode single-photon states, which are suitable for further state
manipulation by means of beam splitter arrays and ON/OFF-detections, and vice
versa. Applications to the realization of unitary and non-unitary
transformations, quantum state reconstruction, and quantum telemanipulation are
studied.Comment: 22 pages, 4 figures, using a4.st
Raman Scattering Study of the Lattice Dynamics of Superconducting LiFeAs
We report an investigation of the lattice dynamical properties of LiFeAs
using inelastic light scattering. Five out of the six expected phonon modes are
observed. The temperature evolution of their frequencies and linewidths is in
good agreement with an anharmonic-decay model. We find no evidence for
substantial electron-phonon coupling, and no superconductivity-induced phonon
anomalies.Comment: 5 pages, 3 figures, 1 tabl
The impact of sexual activity during the third trimester of pregnancy on labor outcome in nulliparous women
Background: In the environment, there’s not enough studies on the effects of sexual activity during pregnancy on labor outcome, especially for nulliparous women. The aim was to assess the effects of sexual activity during the third term of pregnancy on the outcome of labor in nulliparous women.Methods: A prospective cohort study on labor was carried out for 11 months at the labor ward of the Yaoundé gynaeco-obstetric and pediatric Hospital. In this study compared women were exposed to at least one unprotected sexual intercourse with vaginal ejaculation per week during the third trimester of pregnancy (exposed group), to those who had less than one unprotected sexual intercourse per week (non-exposed group).Results: Of the 1123 primiparous women who gave birth within the study period, 426 consented to enroll in the study. Amongst these women, 186 women in the exposed group compared to 240 women in the non-exposed group. Intercourse during pregnancy predisposed on arrival into the labor ward to a Bishop’s score ≥7 (RR = 1.94; CI = 1.63-2.3) and within the course of labor to a spontaneous per vaginal delivery (RR = 1.18; CI = 1.06-1.31) and an active phase duration <6 hours (RR = 1.52; CI = 1.36-1.7). Furthermore, sexual intercourse during pregnancy protected against labor induction (RR = 0.21; CI = 0.12-0.36), dystocia (RR = 0.36; CI = 0.27-0.49), cesarean section (RR = 0.29; CI = 0.15-0.55), episiotomy (RR = 0.56; CI = 0.36-0.87) and an Apgar score <7 at the first minute of birth (RR = 0.31; CI = 0.14-0.7).Conclusions: Sexual activity during pregnancy improves the prognosis of labor in primiparous women. In the absence of contraindications, consented unprotected heterosexual vaginal intercourse should be promoted in nulliparous women
Proteolytic degradation and potential role of onconeural protein cdr2 in neurodegeneration
Cerebellar degeneration-related protein 2 (cdr2) is expressed in the central nervous system, and its ectopic expression in tumor cells of patients with gynecological malignancies elicits immune responses by cdr2-specific autoantibodies and T lymphocytes, leading to neurological symptoms. However, little is known about the regulation and function of cdr2 in neurodegenerative diseases. Because we found that cdr2 is highly expressed in the midbrain, we investigated the role of cdr2 in experimental models of Parkinson's disease (PD). We found that cdr2 levels were significantly reduced after stereotaxic injection of 1-methyl-4-phenylpyridinium (MPP+) into the striatum. cdr2 levels were also decreased in the brains of post-mortem PD patients. Using primary cultures of mesencephalic neurons and MN9D cells, we confirmed that MPP + reduces cdr2 in tyrosine hydroxylase-positive dopaminergic neuronal cells. The MPP+-induced decrease of cdr2 was primarily caused by calpain-and ubiquitin proteasome system-mediated degradation, and cotreatment with pharmacological inhibitors of these enzymes or overexpression of calcium-binding protein rendered cells less vulnerable to MPP+-mediated cytotoxicity. Consequently, overexpression of cdr2 rescued cells from MPP+-induced cytotoxicity, whereas knockdown of cdr2 accelerated toxicity. Collectively, our findings provide insights into the novel regulatory mechanism and potentially protective role of onconeural protein during dopaminergic neurodegeneration. © 2016 Macmillan Publishers Limited All rights reserved.1
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Microstructure and texture analysis of 304 austenitic stainless steel using Bragg edge transmission imaging
Bragg edge imaging using pulsed neutrons is a non-destructive technique for studying microstructure and texture of materials. It provides two-dimensional visualization of crystallographic information using a pixelated gas electron multiplier detector and a time-of-flight method. In this work, the properties of type 304 austenitic stainless steel samples were studied via Bragg edge imaging. The samples included hot-rolled, cold-rolled and heat-treated specimens, which were characterized to investigate texture, phase fraction and grain growth. The results showed that the crystallite size increased with increasing annealing temperature. The cold-rolled and annealed samples exhibited strong textures, while the hot-rolled sample showed no preferred orientation. The phase volume fraction of induced martensite in the cold-rolled sample was also obtained. Two-dimensional maps of microstructures and textures were obtained without destructive processes. The results were validated by electron backscatter diffraction and found to be consistent. This work provides valuable information for non-destructive characterization of bulk materials by performing Bragg edge imaging using the Hokkaido University compact accelerator neutron source
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