17,472 research outputs found
Dissipationless Anomalous Hall Current in Films
The observation of dissipationless anomalous Hall current is one of the
experimental evidences to confirm the intrinsic origin of anomalous Hall
effect. To study the origin of anomalous Hall effect in iron,
Fe(SiO) granular films with volume fraction of SiO
0\le x \le 40.51 were fabricated using co-sputtering. Hall and longitudinal
resistivities were measured in the temperature range 5 to 350 K with magnetic
fields up to 5 Tesla. As x increased from 0 to 40.51, the anomalous Hall
resistivity and longitudinal resistivity increased about 4 and 3 orders in
magnitude, respectively. Analysis of the results revealed that the normalized
anomalous Hall conductivity is a constant for all the samples, the evidence of
dissipationless anomalous Hall current in Fe.Comment: 17 pages, 5 figures;
http://link.aps.org/doi/10.1103/PhysRevB.83.20531
Pattern formation in oscillatory complex networks consisting of excitable nodes
Oscillatory dynamics of complex networks has recently attracted great
attention. In this paper we study pattern formation in oscillatory complex
networks consisting of excitable nodes. We find that there exist a few center
nodes and small skeletons for most oscillations. Complicated and seemingly
random oscillatory patterns can be viewed as well-organized target waves
propagating from center nodes along the shortest paths, and the shortest loops
passing through both the center nodes and their driver nodes play the role of
oscillation sources. Analyzing simple skeletons we are able to understand and
predict various essential properties of the oscillations and effectively
modulate the oscillations. These methods and results will give insights into
pattern formation in complex networks, and provide suggestive ideas for
studying and controlling oscillations in neural networks.Comment: 15 pages, 7 figures, to appear in Phys. Rev.
Generation of Entanglement Outside of the Light Cone
The Feynman propagator has nonzero values outside of the forward light cone.
That does not allow messages to be transmitted faster than the speed of light,
but it is shown here that it does allow entanglement and mutual information to
be generated at space-like separated points. These effects can be interpreted
as being due to the propagation of virtual photons outside of the light cone or
as a transfer of pre-existing entanglement from the quantum vacuum. The
differences between these two interpretations are discussed.Comment: 25 pages, 7 figures. Additional references and figur
Anomalous microwave conductivity coherence peak in c-axis MgB2 thin film
The temperature dependence of the real part of the microwave complex
conductivity at 17.9 GHz obtained from surface impedance measurements of two
c-axis oriented MgB2 thin films reveals a pronounced maximum at a temperature
around 0.6 times the critical temperature. Calculations in the frame of a
two-band model based on Bardeen-Cooper-Schrieffer (BCS) theory suggest that
this maximum corresponds to an anomalous coherence peak resembling the two-gap
nature of MgB2. Our model assumes there is no interband impurity scattering and
a weak interband pairing interaction, as suggested by bandstructure
calculations. In addition, the observation of a coherence peak indicates that
the pi-band is in the dirty limit and dominates the total conductivity of our
filmsComment: 10 pages, 4 figures, to be published in Phys. Rev. Let
Spatial prediction of rotational landslide using geographically weighted regression, logistic regression, and support vector machine models in Xing Guo area (China)
© 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This study evaluated the geographically weighted regression (GWR) model for landslide susceptibility mapping in Xing Guo County, China. In this study, 16 conditioning factors, such as slope, aspect, altitude, topographic wetness index, stream power index, sediment transport index, soil, lithology, normalized difference vegetation index (NDVI), landuse, rainfall, distance to road, distance to river, distance to fault, plan curvature, and profile curvature, were analyzed. Chi-square feature selection method was adopted to compare the significance of each factor with landslide occurence. The GWR model was compared with two well-known models, namely, logistic regression (LR) and support vcector machine (SVM). Results of chi-square feature selection indicated that lithology and slope are the most influencial factors, whereas SPI was found statistically insignificant. Four landslide susceptibility maps were generated by GWR, SGD-LR, SGD-SVM, and SVM models. The GWR model exhibited the highest performance in terms of success rate and prediction accuracy, with values of 0.789 and 0.819, respectively. The SVM model exhibited slightly lower AUC values than that of the GWR model. Validation result of the four models indicates that GWR is a better model than other widely used models
Microscopic correlation between chemical and electronic states in epitaxial graphene on SiC(000-1)
We present energy filtered electron emission spectromicroscopy with spatial
and wave-vector resolution on few layer epitaxial graphene on SiC$(000-1) grown
by furnace annealing. Low energy electron microscopy shows that more than 80%
of the sample is covered by 2-3 graphene layers. C1s spectromicroscopy provides
an independent measurement of the graphene thickness distribution map. The work
function, measured by photoelectron emission microscopy (PEEM), varies across
the surface from 4.34 to 4.50eV according to both the graphene thickness and
the graphene-SiC interface chemical state. At least two SiC surface chemical
states (i.e., two different SiC surface structures) are present at the
graphene/SiC interface. Charge transfer occurs at each graphene/SiC interface.
K-space PEEM gives 3D maps of the k_|| pi - pi* band dispersion in micron scale
regions show that the Dirac point shifts as a function of graphene thickness.
Novel Bragg diffraction of the Dirac cones via the superlattice formed by the
commensurately rotated graphene sheets is observed. The experiments underline
the importance of lateral and spectroscopic resolution on the scale of future
electronic devices in order to precisely characterize the transport properties
and band alignments
Effect of magnetic order on the superfluid response of single-crystal ErNiBC: A penetration depth study
We report measurements of the in-plane magnetic penetration depth (T) in single crystals of ErNiBC down to 0.1 K using
a tunnel-diode based, self-inductive technique at 21 MHz. We observe four
features: (1) a slight dip in (T) at the Nel
temperature = 6.0 K, (2) a peak at = 2.3 K, where a weak
ferromagnetic component sets in, (3) another maximum at 0.45 K, and (4) a final
broad drop down to 0.1 K. Converting to superfluid density , we see
that the antiferromagnetic order at 6 K only slightly depresses
superconductivity. We seek to explain some of the above features in the context
of antiferromagnetic superconductors, where competition between the
antiferromagnetic molecular field and spin fluctuation scattering determines
increased or decreased pairbreaking. Superfluid density data show only a slight
decrease in pair density in the vicinity of the 2.3 K feature, thus supporting
other evidences against bulk ferromagnetism in this temperature range.Comment: 15 pages, 5 figure
Effects of 8-Week Ketogenic Diet on Anthropometrics, Body Composition, Metabolic Parameters, and Psychological Factors in Young Obese Population
Obese have a significantly higher Body Mass Index (BMI), which can be associated with poor nutritional intake and sedentary lifestyles. The ketogenic diet is a form of a dietary intervention which is often implemented for metabolic syndrome individuals such as obese populations. PURPOSE: The purpose of this study was to measure the effects of a ketogenic diet on anthropometrics, body composition, metabolic parameters, and psychological factors in young obese population. METHODS: Seven young obese participants (n=7, height (cm); 174.8 ± 10.9, weight (kg); 105 ± 20.7, BMI (kg∙m-2); 34.6 ± 4.8) completed an 8-week intervention with a 70:20:10 ratio of fats to proteins to carbohydrates. Participants within the study were provided three meals per day, for a total of 8 weeks. Statistical analyses were performed with IBM Statistical Package for Social Science (SPSS 27.0, SPSS Inc., Chicago, USA). All data was reported as mean and standard deviation (SD). Dependent paired t-Test was used to determine ketogenic diet intervention effects. Frequencies were used to measure results from psychological factors. Statistical significance was set a priori p ≤ 0.05. RESULTS: Participants within the study noted significant reductions in anthropometric variables during 8 weeks: body mass (Pre: 105.8 ± 20.5 kg Post: 98.9 ± 18.8 kg, p= 0.000), BMI (Pre: 34.6 ± 4.8 kg·m-2, Post: 32.2 ± 4.2 kg·m-2, p= 0.001), waist circumference (Pre: 101.5 ± 13.9 cm, Post: 96.3 ± 13.3 cm, p= 0.000), and hip circumference (Pre: 112.6 ± 11.5 cm, Post: 107.3 ± 10.8 cm, p= 0.000). Significant reductions were shown in body composition variables: body fat (Pre: 25.6 ± 0.8%, Post: 21.1 ± 1.4%, p=0.000), and lean body mass (Post: 78.9 ± 14.9 kg, Post: 78.2 ± 14.5 kg, p=.0035). Significant reductions were shown in metabolic parameters: systolic blood pressure (Post: 126.6 ± 10.0 mmHg, Post: 120 ± 6.6 mmHg, p=0.029), diastolic blood pressure (Pre: 81.7 ± 4.9 mmHg, Post: 76.3 ± 1.8 mmHg, p= 0.020), and VO2max (Pre: 47.6 ± 8.9 mL·kg-1·min-1, Post: 51.8 ± 9.2 mL·kg-1·min-1, p=0.001. Question 1 within the psychological questionnaire results shown a reduction in the negative aspect in poor health score, with a significant increase shown towards good health. Question 3g results shown that here was a significant increase in frequencies of improvement towards having no limitations regarding walking a one-mile distance. Question 9g had significant increase in individuals selecting improved overall energy levels in comparison to baseline. CONCLUSION: The 8 weeks of ketogenic diet intervention may contribute or change bioenergetics pathways and results in significant adaptations on anthropometrics, body composition, metabolic parameters, and psychological factors in young obese population
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