4,854 research outputs found
Strong Electron-Phonon Interaction and Colossal Magnetoresistance in EuTiO
At low temperatures, EuTiO system has very large resistivities and
exhibits colossal magnetoresistance. Based on a first principle calculation and
the dynamical mean-field theory for small polaron we have calculated the
transport properties of EuTiO. It is found that due to electron-phonon
interaction the conduction band may form a tiny subband which is close to the
Fermi level. The tiny subband is responsible for the large resistivity.
Besides, EuTiO is a weak antiferromagnetic material and its magnetization
would slightly shift the subband via exchange interaction between conduction
electrons and magnetic atoms. Since the subband is close to the Fermi level, a
slight shift of its position gives colossal magnetoresistance.Comment: 6 pages, 5 figure
Processing of Individual Items during Ensemble Coding of Facial Expressions
There is growing evidence that human observers are able to extract the mean emotion or other type of information from a set of faces. The most intriguing aspect of this phenomenon is that observers often fail to identify or form a representation for individual faces in a face set. However, most of these results were based on judgments under limited processing resource. We examined a wider range of exposure time and observed how the relationship between the extraction of a mean and representation of individual facial expressions would change. The results showed that with an exposure time of 50 ms for the faces, observers were more sensitive to mean representation over individual representation, replicating the typical findings in the literature. With longer exposure time, however, observers were able to extract both individual and mean representation more accurately. Furthermore, diffusion model analysis revealed that the mean representation is also more prone to suffer from the noise accumulated in redundant processing time and leads to a more conservative decision bias, whereas individual representations seem more resistant to this noise. Results suggest that the encoding of emotional information from multiple faces may take two forms: single face processing and crowd face processi
Generating axial magnetic fields via two plasmon decay driven by a twisted laser
We propose a new way of axial magnetic fields generation in a
non-relativistic laser intensity regime by using a twisted light carrying
orbital angular momentum (OAM) to stimulate two-plasmon decay (TPD) in a
plasma. The growth of TPD driven by an OAM light in a Laguerre-Gauss (LG) mode
is investigated through three dimensional fluid simulations and theory. A
theory based on the assumption that the electron plasma waves (EPWs) are
locally driven by a number of local plane-wave lasers predicts the maximum
growth rate proportional to the peak amplitude of the pump laser field and is
verified by the simulations. The OAM conservation during its transportation
from the laser to the TPD daughter EWPs is shown by both the theory and the
simulations. The theory predicts generation of ~40T axial magnetic fields
through the OAM absorption via TPD, which has perspective applications in the
field of high energy density physics.Comment: 6 pages, 3 figures
Electrically-controllable RKKY interaction in semiconductor quantum wires
We demonstrate in theory that it is possible to all-electrically manipulate
the RKKY interaction in a quasi-one-dimensional electron gas embedded in a
semiconductor heterostructure, in the presence of Rashba and Dresselhaus
spin-orbit interaction. In an undoped semiconductor quantum wire where
intermediate excitations are gapped, the interaction becomes the short-ranged
Bloembergen-Rowland super-exchange interaction. Owing to the interplay of
different types of spin-orbit interaction, the interaction can be controlled to
realize various spin models, e.g., isotropic and anisotropic Heisenberg-like
models, Ising-like models with additional Dzyaloshinsky-Moriya terms, by tuning
the external electric field and designing the crystallographic directions. Such
controllable interaction forms a basis for quantum computing with localized
spins and quantum matters in spin lattices.Comment: 5 pages, 1 figur
Application of High-Gradient Magnetic Separation for the Recovery of Super-Paramagnetic Polymer Adsorbent Used in Adsorption and Desorption Processes
Bacteremic pneumonia caused by extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae: Appropriateness of empirical treatment matters
BackgroundClinical information about bacteremic pneumonia caused by extended-spectrum beta-lactamase (ESBL)-producing organism is limited.MethodsA retrospective study was conducted at two medical centers in Taiwan. From May 2002 to August 2010, clinical information and outcome of adults with bacteremic pneumonia caused by ESBL-producing Escherichia coli and Klebsiella pneumoniae were analyzed. The primary outcome is the 30-day mortality.ResultsA total of 111 patients with bacteremic pneumonia caused by E. coli (37 patients, 33.3%) and K. pneumoniae (74, 66.7%) were identified. Their mean age was 69.2 years and 51.4% were male patients. Fifty-seven (51.3%) episodes were classified as hospital-acquired infections, 19 (17.1%) as health-care-associated infections, and four (3.6%) as community-acquired infections. Fifty-one (45.9%) patients received appropriate empiric antimicrobial therapy. The 30-day mortality rate was 40.5% (45 patients). In the multivariate analysis, several independent risk factors, including rapidly fatal underlying disease [odds ratio (OR), 5.75; 95% confidence interval (CI), 1.54ā21.48; pĀ =Ā 0.009], severe sepsis (OR, 4.84; 95% CI, 1.55ā15.14; pĀ =Ā 0.007), critical illness (OR, 4.28; 95% CI, 1.35ā13.57; pĀ =Ā 0.013), and receipt of appropriate empirical therapy (OR, 0.19; 95% CI, 0.07ā0.55; pĀ =Ā 0.002), were associated with 30-day mortality. The survival analysis consistently found that individuals with appropriate empiric therapy had a higher survival rate (log-rank test, pĀ <Ā 0.001).ConclusionESBL-producing bacteremic pneumonia, especially health-care-associated infections, often occurred in adults with comorbidities. Appropriate empirical therapy was associated with a favorable outcome
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