24,374 research outputs found
Phase diagram and spin-glass phenomena in electron-doped La1-xHfxMnO3 (0.05 β€ x β€ 0.3) manganite oxides
The effects of tetravalent hafnium doping on the structural, transport, and magnetic properties of polycrystalline La1βxHfxMnO3 (LHMO) (0.05ββ€βxββ€β0.3) were investigated systematically. LHMO exhibited a typical colossal magnetoresistance effect via the double-exchange between Mn2+ and Mn3+ ions, instead of that between Mn3+ and Mn4+ ions in hole-doped manganites. A phase diagram was obtained for the first time through magnetization and resistance measurements in a broad temperature range. As the Hf concentration varied from xβ=β0.05 to 0.3, the Curie point and metal-to-insulator transition temperature increased significantly, whereas the magnetization and resistivity decreased remarkably. An abnormal enhancement of the magnetization was observed at about 42 K. It was further confirmed that a second magnetic phase MnO2 in LHMO gives rise to such a phenomenon. The possible causes are discussed in detail. The dynamic magnetic properties of LHMO, including relaxation and aging processes, were studied, demonstrating a spin-glass state at low temperature accompanied by a ferromagnetic phase.published_or_final_versio
Asymmetric interlimb transfer of concurrent adaptation to opposing dynamic forces
Interlimb transfer of a novel dynamic force has been well documented. It has also been shown that unimanual adaptation to opposing novel environments is possible if they are associated with different workspaces. The main aim of this study was to test if adaptation to opposing velocity dependent viscous forces with one arm could improve the initial performance of the other arm. The study also examined whether this interlimb transfer occurred across an extrinsic, spatial, coordinative system or an intrinsic, joint based, coordinative system. Subjects initially adapted to opposing viscous forces separated by target location. Our measure of performance was the correlation between the speed profiles of each movement within a force condition and an βaverageβ trajectory within null force conditions. Adaptation to the opposing forces was seen during initial acquisition with a significantly improved coefficient in epoch eight compared to epoch one. We then tested interlimb transfer from the dominant to non-dominant arm (D β ND) and vice-versa (ND β D) across either an extrinsic or intrinsic coordinative system. Interlimb transfer was only seen from the dominant to the non-dominant limb across an intrinsic coordinative system. These results support previous studies involving adaptation to a single dynamic force but also indicate that interlimb transfer of multiple opposing states is possible. This suggests that the information available at the level of representation allowing interlimb transfer can be more intricate than a general movement goal or a single perceived directional error
Imaging characteristics and treatment of a penetrating brain injury caused by an oropharyngeal foreign body in a dog
A 4-year-old Border collie was presented with one episode of collapse, altered mentation, and a suspected pharyngeal stick injury. Magnetic resonance imaging (MRI) and computed tomography showed a linear foreign body penetrating the right oropharynx, through the foramen ovale and the brain parenchyma. The foreign body was surgically removed and medical treatment initiated. Complete resolution of clinical signs was noted at recheck 8 weeks later. Repeat MRI showed chronic secondary changes in the brain parenchyma. To the authors' knowledge, this is the first report of the advanced imaging findings and successful treatment of a penetrating oropharyngeal intracranial foreign body in a dog
Predicting Fluid Intelligence of Children using T1-weighted MR Images and a StackNet
In this work, we utilize T1-weighted MR images and StackNet to predict fluid
intelligence in adolescents. Our framework includes feature extraction, feature
normalization, feature denoising, feature selection, training a StackNet, and
predicting fluid intelligence. The extracted feature is the distribution of
different brain tissues in different brain parcellation regions. The proposed
StackNet consists of three layers and 11 models. Each layer uses the
predictions from all previous layers including the input layer. The proposed
StackNet is tested on a public benchmark Adolescent Brain Cognitive Development
Neurocognitive Prediction Challenge 2019 and achieves a mean squared error of
82.42 on the combined training and validation set with 10-fold
cross-validation. In addition, the proposed StackNet also achieves a mean
squared error of 94.25 on the testing data. The source code is available on
GitHub.Comment: 8 pages, 2 figures, 3 tables, Accepted by MICCAI ABCD-NP Challenge
2019; Added ND
Expression quantitative trait loci are highly sensitive to cellular differentiation state
Blood cell development from multipotent hematopoietic stem cells to specialized blood cells is accompanied by drastic changes in gene expression for which the triggers remain mostly unknown. Genetical genomics is an approach linking natural genetic variation to gene expression variation, thereby allowing the identification of genomic loci containing gene expression modulators (eQTLs). In this paper, we used a genetical genomics approach to analyze gene expression across four developmentally close blood cell types collected from a large number of genetically different but related mouse strains. We found that, while a significant number of eQTLs (365) had a consistent βstaticβ regulatory effect on gene expression, an even larger number were found to be very sensitive to cell stage. As many as 1,283 eQTLs exhibited a βdynamicβ behavior across cell types. By looking more closely at these dynamic eQTLs, we show that the sensitivity of eQTLs to cell stage is largely associated with gene expression changes in target genes. These results stress the importance of studying gene expression variation in well-defined cell populations. Only such studies will be able to reveal the important differences in gene regulation between different ce
A study on the interacting Ricci dark energy in gravity
The present work reports study on the interacting Ricci dark energy in a
modified gravity theory named gravity. The specific model (proposed by R. Myrzakulov, arXiv:1205.5266v2) is considered here. For
this model we have observed a quintom-like behavior of the equation of state
(EoS) parameter and a transition from matter dominated to dark energy density
has been observed through fraction density evolution. The statefinder
parameters reveal that the model interpolates between dust and CDM
phases of the universe.Comment: 12 pages, 5 figure
Deep Shape Matching
We cast shape matching as metric learning with convolutional networks. We
break the end-to-end process of image representation into two parts. Firstly,
well established efficient methods are chosen to turn the images into edge
maps. Secondly, the network is trained with edge maps of landmark images, which
are automatically obtained by a structure-from-motion pipeline. The learned
representation is evaluated on a range of different tasks, providing
improvements on challenging cases of domain generalization, generic
sketch-based image retrieval or its fine-grained counterpart. In contrast to
other methods that learn a different model per task, object category, or
domain, we use the same network throughout all our experiments, achieving
state-of-the-art results in multiple benchmarks.Comment: ECCV 201
Complement-Mediated Virus Infectivity Neutralisation by HLA Antibodies Is Associated with Sterilising Immunity to SIV Challenge in the Macaque Model for HIV/AIDS.
Sterilising immunity is a desired outcome for vaccination against human immunodeficiency virus (HIV) and has been observed in the macaque model using inactivated simian immunodeficiency virus (SIV). This protection was attributed to antibodies specific for cell proteins including human leucocyte antigens (HLA) class I and II incorporated into virions during vaccine and challenge virus preparation. We show here, using HLA bead arrays, that vaccinated macaques protected from virus challenge had higher serum antibody reactivity compared with non-protected animals. Moreover, reactivity was shown to be directed against HLA framework determinants. Previous studies failed to correlate serum antibody mediated virus neutralisation with protection and were confounded by cytotoxic effects. Using a virus entry assay based on TZM-bl cells we now report that, in the presence of complement, serum antibody titres that neutralise virus infectivity were higher in protected animals. We propose that complement-augmented virus neutralisation is a key factor in inducing sterilising immunity and may be difficult to achieve with HIV/SIV Env-based vaccines. Understanding how to overcome the apparent block of inactivated SIV vaccines to elicit anti-envelope protein antibodies that effectively engage the complement system could enable novel anti-HIV antibody vaccines that induce potent, virolytic serological response to be developed
Suppression of photoconductivity by magnetic field in epitaxial manganite thin films
The erasure of photoinduced resistance (PR) by the magnetic field was investigated in manganite films. The PR was significantly suppressed when a magnetic field was introduced at low temperature. The decrease (or increase) of PR with increment of magnetic field was observed in ferromagnetic (or paramagnetic) phases of films, respectively. Our results are suggested to be the coaction of two effects under magnetic fields: (i) the reorientation of domains and spin directions of photoexcited carriers and (ii) electrons trapped around oxygen vacancies released and recombined with majority carriers in films. The interplay of the external fields is a good demonstration of the strong coupling between spins and charges in colossal magnetoresistance materials. Β© 2012 American Institute of Physics.published_or_final_versio
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