6,919 research outputs found
Large magnetic circular dichroism in resonant inelastic x-ray scattering at the Mn L-edge of Mn-Zn ferrite
We report resonant inelastic x-ray scattering (RIXS) excited by circularly
polarized x-rays on Mn-Zn ferrite at the Mn L2,3-resonances. We demonstrate
that crystal field excitations, as expected for localized systems, dominate the
RIXS spectra and thus their dichroic asymmetry cannot be interpreted in terms
of spin-resolved partial density of states, which has been the standard
approach for RIXS dichroism. We observe large dichroic RIXS at the L2-resonance
which we attribute to the absence of metallic core hole screening in the
insulating Mn-ferrite. On the other hand, reduced L3-RIXS dichroism is
interpreted as an effect of longer scattering time that enables spin-lattice
core hole relaxation via magnons and phonons occurring on a femtosecond time
scale.Comment: 7 pages, 2 figures,
http://link.aps.org/doi/10.1103/PhysRevB.74.17240
Identification of network modules by optimization of ratio association
We introduce a novel method for identifying the modular structures of a
network based on the maximization of an objective function: the ratio
association. This cost function arises when the communities detection problem
is described in the probabilistic autoencoder frame. An analogy with kernel
k-means methods allows to develop an efficient optimization algorithm, based on
the deterministic annealing scheme. The performance of the proposed method is
shown on a real data set and on simulated networks
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Testing the accuracy of an observation-based classifier for rapid detection of autism risk
Current approaches for diagnosing autism have high diagnostic validity but are time consuming and can contribute to delays in arriving at an official diagnosis. In a pilot study, we used machine learning to derive a classifier that represented a 72% reduction in length from the gold-standard Autism Diagnostic Observation Schedule-Generic (ADOS-G), while retaining >97% statistical accuracy. The pilot study focused on a relatively small sample of children with and without autism. The present study sought to further test the accuracy of the classifier (termed the observation-based classifier (OBC)) on an independent sample of 2616 children scored using ADOS from five data repositories and including both spectrum (n=2333) and non-spectrum (n=283) individuals. We tested OBC outcomes against the outcomes provided by the original and current ADOS algorithms, the best estimate clinical diagnosis, and the comparison score severity metric associated with ADOS-2. The OBC was significantly correlated with the ADOS-G (r=−0.814) and ADOS-2 (r=−0.779) and exhibited >97% sensitivity and >77% specificity in comparison to both ADOS algorithm scores. The correspondence to the best estimate clinical diagnosis was also high (accuracy=96.8%), with sensitivity of 97.1% and specificity of 83.3%. The correlation between the OBC score and the comparison score was significant (r=−0.628), suggesting that the OBC provides both a classification as well as a measure of severity of the phenotype. These results further demonstrate the accuracy of the OBC and suggest that reductions in the process of detecting and monitoring autism are possible
Positions of septal papillary muscles in human hearts
Septal papillary muscles, similarly to other papillary muscles, are essential elements
of the heart valvular system. Damage to their structure may lead to
a considerable life risk.
Of all the papillary muscles, the septal papillary muscles are characterized by
the greatest topographical and morphological variability. However, information
about these muscles is scarce and fragmentary. The objective of this study
was to ascertain their occurrence and the region in which they are placed in
the inter-ventricular septum.
One hundred and eleven human hearts were examined. The hearts belonged
to the Clinical Anatomy Department of the Medical University of Gdańsk. They
were fixed in formalin with ethanol and came from middle-aged and older
individuals of both sexes, devoid of pathological changes and birth defects.
During the tests, classic anatomical methods were applied.
The region where the papillary muscles are found covers a sizeable surface of
the septum, from the conus arteriosus up to the back angle of the right chamber.
Depending on their location the following septal papillary muscles (musculi
papillares septales, MPS) were singled out: 1) lying on the front wall of the
septum (anterior papillares septales), 2) in the central part of the septum (central
muscles), and 3) in the posterior section of the septum (posterior papillares
septales). A trial to determine the types of MPS was based on this diversity of
location. Consequently, five types of MPS were specified: type I: anterior-central
(44.1%); type II: anterior (15.3%); type III: anterior-posterior (13.5%); type IV:
anterior-central-posterior (24.3%); and type V: uniform (2.75%).
This study is an attempt to systematize and standardize the terminology of
these structures. (Folia Morphol 2010; 69, 2: 101-106
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