106 research outputs found
Critical Rotational Frequency for Superfluid Fermionic Gases across a Feshbach Resonance
We present a method to determine the critical rotational frequencies for
superfluidity of both uniform and trapped Fermi gases across wide Feshbach
resonance. It is found that as one approaches the resonance from the BCS side,
beyond a critical scattering length, pairing is so robust that superfluidity
cannot be destroyed by rotation. Moreover, the critical frequency has a
sequence of jumps revealing the appearance of Landau levels, which are
particularly prominent for systems up to a few thousand particles. For
rotational frequency below an "ultimate" critical frequency, defined to be the
lowest frequency at which the center of the cloud goes normal, a trapped gas
has a superfluid core surrounded by a normal gas, as seen in recent
experiments.Comment: 4 pages, 2 figures, published versio
Criterion for bosonic superfluidity in an optical lattice
We show that the current method of determining superfluidity in optical
lattices based on a visibly sharp bosonic momentum distribution
can be misleading, for even a normal Bose gas can have a similarly sharp
. We show that superfluidity in a homogeneous system can be
detected from the so-called visibility of that must
be 1 within , where is the number of bosons. We also show that
the T=0 visibility of trapped lattice bosons is far higher than what is
obtained in some current experiments, suggesting strong temperature effects and
that these states can be normal. These normal states allow one to explore the
physics in the quantum critical region.Comment: 4 pages, 2 figures; published versio
Factors Related to Health Status among Nurses in Taiwan
Nurses play an important role in healthcare institutions. Improving the nurses’ health status and increasing nurses’ enthusiasm in clinical nursing can improve the quality of healthcare. The purposes of this study include: (1) to understand the basic characteristics of the participants, and health status; (2) to analyze the differences in health status between different demographic of the participants.The study adopted stratified and cluster sampling, and used a cross-sectional descriptive design. A total of 256 registered nurses and licensed vocational nurses were recruited for the study who have been working in the position for at least one year in a medical center in northern Taiwan. Research tools included basic properties, and the Chinese Health Questionnaire. Data were analyzed with SPSS for Windows 187.0 (Chinese) software for descriptive statistics, t-test, and one-way ANOVA.To summarize, we found the following: (1) Participants’ average age was 29.8 years, and most participants were single, childless women with bachelor’s degrees or above, not living with their in-laws, N1 ranked, working on shift, and not participating in health courses. (3) Participants’ health status were found significant differences among gender, education degree, and whether or not they had children. The findings of this study provide a reference for management decision making
Ursolic acid inhibits the initiation, progression of prostate cancer and prolongs the survival of TRAMP mice by modulating pro-inflammatory pathways
10.1371/journal.pone.0032476PLoS ONE73
Homogeneous Fermion Superfluid with Unequal Spin Populations
For decades, the conventional view is that an s-wave BCS superfluid can not
support uniform spin polarization due to a gap in the quasiparticle
excitation spectrum. We show that this is an artifact of the dismissal of
quasiparticle interactions in the conventional approach at the
outset. Such interactions can cause triplet fluctuations in the ground state
and hence non-zero spin polarization at "magnetic field" . The
resulting ground state is a pairing state of quasiparticles on the ``BCS
vacuum". For sufficiently large , the spin polarization of at unitarity
has the simple form . Our study is motivated by the recent
experiments at Rice which found evidence of a homogenous superfluid state with
uniform spin polarization.Comment: 4 pages, 3 figure
Proximity-induced quasi-one-dimensional superconducting quantum anomalous Hall state: a promising scalable top-down approach towards localized Majorana modes
In this work, ~100 nm wide quantum anomalous Hall insulator (QAHI)
nanoribbons are etched from a two-dimensional QAHI film. One part of the
nanoribbon is covered with superconducting Nb, while the other part is
connected to an Au lead via two-dimensional QAHI regions. Andreev reflection
spectroscopy measurements were performed, and multiple in-gap conductance peaks
were observed in three different devices. In the presence of an increasing
magnetic field perpendicular to the QAHI film, the multiple in-gap peak
structure evolves into a single zero-bias conductance peak (ZBCP). Theoretical
simulations suggest that the measurements are consistent with the scenario that
the increasing magnetic field drives the nanoribbons from a multi-channel
occupied regime to a single channel occupied regime, and that the ZBCP may be
induced by zero energy Majorana modes as previously predicted [24]. Although
further experiments are needed to clarify the nature of the ZBCP, we provide
initial evidence that quasi-1D QAHI nanoribbon/superconductor heterostructures
are new and promising platforms for realizing zero-energy Majorana modes
The natural retinoprotectant chrysophanol attenuated photoreceptor cell apoptosis in an N-methyl-N-nitrosourea-induced mouse model of retinal degenaration
Retinitis pigmentosa (RP) is an inherited photoreceptor-degenerative disease, and neuronal degeneration in RP is exacerbated by glial activation. Cassia seed (Jue-ming-zi) is a traditional herbal medicine commonly used to treat ocular diseases in Asia. In this report, we investigated the retina-protective effect of chrysophanol, an active component of Cassia seed, in an N-methyl-N-nitrosourea (MNU)-induced mouse model of RP. We determined that chrysophanol inhibited the functional and morphological features of MNU-induced retinal degeneration using scotopic electroretinography (ERG), optical coherence tomography (OCT), and immunohistochemistry analysis of R/G opsin and rhodopsin. Furthermore, TUNEL assays revealed that chrysophanol attenuated MNU-induced photoreceptor cell apoptosis and inhibited the expression of the apoptosis-associated proteins PARP, Bax, and caspase-3. In addition, chrysophanol ameliorated reactive gliosis, as demonstrated by a decrease in GFAP immunolabeling, and suppressed the activation of matrix metalloproteinase (MMP)-9-mediated gelatinolysis. In vitro studies indicated that chrysophanol inhibited lipopolysaccharide (LPS)-induced iNOS and COX-2 expression in the BV2 mouse microglia cell line and inhibited MMP-9 activation in primary microglia. Our results demonstrate that chrysophanol provided neuroprotective effects and inhibited glial activation, suggesting that chrysophanol might have therapeutic value for the treatment of human RP and other retinopathies
The prediction of Alzheimer’s disease through multi-trait genetic modeling
To better capture the polygenic architecture of Alzheimer’s disease (AD), we developed a joint genetic score, MetaGRS. We incorporated genetic variants for AD and 24 other traits from two independent cohorts, NACC (n = 3,174, training set) and UPitt (n = 2,053, validation set). One standard deviation increase in the MetaGRS is associated with about 57% increase in the AD risk [hazard ratio (HR) = 1.577, p = 7.17 E-56], showing little difference from the HR for AD GRS alone (HR = 1.579, p = 1.20E-56), suggesting similar utility of both models. We also conducted APOE-stratified analyses to assess the role of the e4 allele on risk prediction. Similar to that of the combined model, our stratified results did not show a considerable improvement of the MetaGRS. Our study showed that the prediction power of the MetaGRS significantly outperformed that of the reference model without any genetic information, but was effectively equivalent to the prediction power of the AD GRS
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