2,870 research outputs found
Spin wave dispersion softening in the ferromagnetic Kondo lattice model for manganites
Spin dynamics is calculated in the ferromagnetic (FM) state of the
generalized Kondo lattice model taking into account strong on-site correlations
between e_g electrons and antiferromagnetic (AFM) exchange among t_{2g} spins.
Our study suggests that competing FM double-exchange and AFM super-exchange
interaction lead to a rather nontrivial spin-wave spectrum. While spin
excitations have a conventional Dq^2 spectrum in the long-wavelength limit,
there is a strong deviation from the spin-wave spectrum of the isotropic
Heisenberg model close to the zone boundary. The relevance of our results to
the experimental data are discussed.Comment: 6 RevTex pages, 3 embedded PostScript figure
Eosinophils, probiotics, and the microbiome
There is currently substantial interest in the therapeutic
properties of probiotic microorganisms as recent research suggests that oral administration of specific
bacterial strains may reduce inflammation and alter the
nature of endogenous microflora in the gastrointestinal
tract. Eosinophils are multifunctional tissue leukocytes,
prominent among the resident cells of the gastrointestinal mucosa that promote local immunity. Recent studies
with genetically altered mice indicate that eosinophils not
only participate in maintaining gut homeostasis, but that
the absence of eosinophils may have significant impact
on the nature of the endogenous gut microflora and
responses to gut pathogens, notably Clostridium difficile.
Furthermore, in human subjects, there is an intriguing
relationship between eosinophils, allergic inflammation,
and the nature of the lung microflora, notably a distinct
association between eosinophil infiltration and detection
of bacteria of the phylum Actinobacteria. Among topics
for future research, it will be important to determine
whether homeostatic mechanisms involve direct interactions between eosinophils and bacteria or whether
they involve primarily eosinophil-mediated responses to
cytokine signaling in the local microenvironment. Likewise, although is it clear that eosinophils can and do
interact with bacteria in vivo, their ability to discern
between pathogenic and probiotic species in various
settings remains to be explored
A mobile antineutrino detector with plastic scintillators
We propose a new type segmented antineutrino detector made of plastic
scintillators for the nuclear safeguard application. A small prototype was
built and tested to measure background events. A satisfactory unmanned field
operation of the detector system was demonstrated. Besides, a detailed Monte
Carlo simulation code was developed to estimate the antineutrino detection
efficiency of the detector.Comment: 23 pages, 11 figures; accepted for publication in Nuclear Instruments
and Methods in Physics Research
Single-qubit gates and measurements in the surface acoustic wave quantum computer
In the surface acoustic wave quantum computer, the spin state of an electron
trapped in a moving quantum dot comprises the physical qubit of the scheme. Via
detailed analytic and numerical modeling of the qubit dynamics, we discuss the
effect of excitations into higher-energy orbital states of the quantum dot that
occur when the qubits pass through magnetic fields. We describe how
single-qubit quantum operations, such as single-qubit rotations and
single-qubit measurements, can be performed using only localized static
magnetic fields. The models provide useful parameter regimes to be explored
experimentally when the requirements on semiconductor gate fabrication and the
nanomagnetics technology are met in the future.Comment: 13 pages, 10 figures, submitted to Phys. Rev.
Fundamental properties of Tsallis relative entropy
Fundamental properties for the Tsallis relative entropy in both classical and
quantum systems are studied. As one of our main results, we give the parametric
extension of the trace inequality between the quantum relative entropy and the
minus of the trace of the relative operator entropy given by Hiai and Petz. The
monotonicity of the quantum Tsallis relative entropy for the trace preserving
completely positive linear map is also shown without the assumption that the
density operators are invertible.
The generalized Tsallis relative entropy is defined and its subadditivity is
shown by its joint convexity. Moreover, the generalized Peierls-Bogoliubov
inequality is also proven
Development of a score for assessment of radiologic damage in large-vessel vasculitis (Combined Arteritis Damage Score, CARDS)
OBJECTIVES:
Outcome assessment in large-vessel vasculitis (LVV) remains challenging and this impairs patient management and the conduct of clinical studies. Previous proposals for outcome tools have not included imaging. This study aimed to develop an imaging score to quantify damage in LVV and to assess the difference between Takayasu (TAK) and giant cell arteritis (GCA).
METHODS:
Ninety-six patients (41 TAK, 55 GCA) were identified from local registries at two University Hospitals in the UK. Radiologic lesions including stenosis, occlusion and aneurysm were evaluated in 25 arterial regions by enhanced computed tomography or magnetic resonance angiography. Lesion correlation with combined damage assessment scores was employed in a multiple regression analysis to define the weight of individual lesions and develop a damage index.
RESULTS:
A numerical damage index was developed: the “Combined Arteritis Damage Score (CARDS)”. The index was derived from a formula: number of regions with mild stenosis × 0.6 + number of regions with moderate to severe stenosis × 1.2 + number with occlusions × 1.6 + number with aneurysms × 0.8 in 25 arterial regions. The median CARDS was higher in TAK than GCA (4.1 and 0.6, interquartile range 1.3-5.7 and 0-3, p<0.001).
CONCLUSIONS:
We have developed a damage assessment tool, CARDS, based on imaging in LVV of potential value to clinical studies and patient management. TAK and GCA differ in the radiologic severity of disease.Dr. Daiki Nakagomi is supported by the Japan College of Rheumatology and Shimoshizu Hospital, National Hospital Organization. This project was supported by the Cambridge Biomedical Research Centre
Thermocurrents and their Role in high Q Cavity Performance
Over the past years it became evident that the quality factor of a
superconducting cavity is not only determined by its surface preparation
procedure, but is also influenced by the way the cavity is cooled down.
Moreover, different data sets exists, some of them indicate that a slow
cool-down through the critical temperature is favourable while other data
states the exact opposite. Even so there where speculations and some models
about the role of thermo-currents and flux-pinning, the difference in behaviour
remained a mystery. In this paper we will for the first time present a
consistent theoretical model which we confirmed by data that describes the role
of thermo-currents, driven by temperature gradients and material transitions.
We will clearly show how they impact the quality factor of a cavity, discuss
our findings, relate it to findings at other labs and develop mitigation
strategies which especially addresses the issue of achieving high quality
factors of so-called nitrogen doped cavities in horizontal test
Teaching Students with Special Educational Needs in an Inclusive Educational Setting in Sri Lanka: Regular Class Teacher’s View
This study examined how regular class teachers view teaching students with special educational needs (SEN) in Sri Lankan government schools. Three types of schools in three education zones were visited and 36 teachers were interviewed. The results revealed that all the participants recognized the presence of a student with SEN in their classes, and majority of them were aware that they had given some sorts of accommodations/modifications to teach them. In addition, it was found teachers felt they were supported especially from the school administrators. Results also indicated that teachers face stress or dilemmas when balancing classes to meet the needs of both students with and without SEN. However, there was a pitfall in coordination between teachers of regular classes and special units. More training and seminar need to be introduced on inclusive education strategies and philosophy that reinforces teachers’ professional ideas of accepting students in need.This research was conducted as a part of the project on the topic concerning “Educational Policy Research on Equity and Inclusion in the Asia-Pacific Region” carried out by Prof. Kazuo Kuroda, Center for the study of International Cooperation in Education, Waseda University, and funded by the Official Development Assistance of the Japanese National Commission for UNESCO, Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan
Lax pair and Darboux transformation of noncommutative U(N) principal chiral model
We present a noncommutative generalization of Lax formalism of U(N) principal
chiral model in terms of a one-parameter family of flat connections. The Lax
formalism is further used to derive a set of parametric noncommutative
B\"{a}cklund transformation and an infinite set of conserved quantities. From
the Lax pair, we derive a noncommutative version of the Darboux transformation
of the model.Comment: 1+20 page
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