The present study investigated if the emotional valence of words modulates the subliminal repetition priming effect in the brain, in particular, the occipitotemporal visual cortex, by adopting a ...rapid presentation event-related fMRI design. A masked repetition priming paradigm was adopted, in which, before the presentation of the target (either positive or negative or neutral in meaning), a masked prime word that was either a repetition or an unrelated word of the target was presented. The subject made a perceptual judgment on the target. The results revealed that the left mid-fusiform gyrus was sensitive to the emotional manipulation of the repetition priming effect and that the priming effect in the region was greater in the positive than in the negative word condition. The priming effect in the fusiform gyrus in neutral words was not significant, which might be a result of suppression caused by the emotional context. No effect of valence or repetition was found in the amygdala.
In this study, Fe/Ag/Fe/Ag ferromagnetic structures were epitaxially grown on a GaAs(1
0
0) substrate. Using the Network Analyzer (Agilent 8510C), FMR (ferromagnetic resonant) signals were observed ...in samples as the in-plane magnetic field was applied to either hard- or easy-axes. Of interest was that our sample demonstrated a FMR-switching behavior in hard-axis but not in easy-axis. The detecting data showed that the switch magnetic field was much smaller than what has been stated previously in Fe/Cu/Fe systems by other laboratories. In addition to the frequency switch in FMR, we also observed a magnetic reversal behavior in its
M–
H curve. Data presented that both of the FMR and magnetic reverse took place in the same direction (hard-axis).
Microwave properties were investigated in Ta/NiFe N_{i 81} F_{e 19} \approx. Permalloy, Py) bilayer system using electrically driven spin torque ferromagnetic resonance (STFMR) technique focusing ...particularly using frequency sweep measurements. Frequency sweep STFMR signals were detected via spin Hall effect of Ta. This technique was optimized for achieving high signal-to-noise (SNR) ratio and anisotropic magnetoresistance of 1.5% was achieved. The Gilbert damping constant can be tuned by applying an electric current which shows the evidence of spin torque in the system. The value of \alpha is found to be 0.0085 \pm 0.0002 at I_{\mathrm{dc}}=0 \mathrm{mA}. Further, \theta_{\mathrm{SH}}=-0.160 \pm 0.027, an important parameter describing performance of Ta was calculated and the parameters quantified corroborate with widely used field sweep technique discussed in literature. The interface transparency, T=\sim 0.40, is large which accounts for the flow of spin current density that diffuses into the Py layer via SHE of Ta. Further, these studies are beneficial for the development of Ta/Py based spin Hall nano-oscillators (SHNO) which can generate RF power by application of dc current.
We report studies of magnetic anisotropy in Fe films of various thicknesses grown on GaAs(001) with MgO as a capping layer. Deposition was done in an ultrahigh vacuum chamber at room temperature. ...Ferromagnetic Resonance (FMR) has been used to investigate the anisotropy in the films. Fe films of thickness 20 monolayers (ML) and 25 ML showed the presence of both four-fold and in-plane uniaxial magnetic anisotropies. In Fe films of thickness as high as 50 ML the spectra showed different number of peaks at different in-plane angles of applied magnetic field. This could be understood as being due to the presence of a mixture of both uniaxial and four-fold anisotropies in the films. The anisotropy constants are evaluated. The interface of MgO with Fe is found to be one of the factors that influence the anisotropy towards a uniaxial nature.
The high frequency dynamic magnetic responses of FeCo thin films and structures have been investigated mainly using ferromagnetic resonance (FMR) technique. The FMR resonance condition and linewidth ...are first derived from the dynamic Landau- Lifshitz-Gilbert equation, followed by a study of the conversion between FMR field and frequency linewidths. It is found that the linewidth conversion relation based on the derivative of resonance condition is only valid for samples with negligible extrinsic linewidth contribution. The dynamic magnetic properties obtained by using FMR measurements of FeCo thin films grown on Si/SiO2 substrates with varying deposition temperatures is then presented. The effective Landé g-factor, extrinsic linewidth, and Gilbert relaxation rate are all found to decrease in magnitude with increasing sample growth temperature from 20oC to about 400–500oC and then on further increase of the growth temperature to increase in magnitude. Samples grown at about 400–450oC display the smallest coercivity, while the smallest value of the Gilbert relaxation rate of about 0.1 GHz is obtained for samples grown at 450–500oC. An almost linear relation between extrinsic linewidth and coercivity is observed, which suggests a positive correlation between magnetic inhomogeneity, coercivity and extrinsic linewidth. Another major discovery in this study is that the Gilbert relaxation decreases with increasing lattice constant, which is ascribed to the degree of structural order in the films. A micromagnetic model is established for an asymmetric trilayer system consisting of two different ferromagnetic (FM) layers separated by thin non-magnetic (NM) layer, treating the magnetization in each FM layer as a macrospin. Based on the model, numerical simulations of magnetization curves and FMR dispersion relations, of both the acoustic mode where magentizations in the two FM layers precess in phase and the optic mode where they precess out-of-phase, have been carried out. The most significant implication from the results is that the coupling strength can be extracted by detecting only the acoustic mode resonances at many different unsaturated magnetic states using broadband FMR technique. Finally, trilayer films of FeCo(100 Å)/NM/FeNi(100 Å) with NM=Ru or Cu were prepared and studied. The thickness of the Ru and Cu spacer was varied from 0 to 50 Å. For the Ru spacer series, the film with 10 Å Ru spacer shows antiferromagnetic coupling while all other films are ferromagnetically coupled. For the Cu spacer trilayers, it is found that all films are ferromagnetically coupled and that films with thin Cu spacer are surprisingly strongly coupled (the coupling constant is 3 erg/cm2 for the sample with 5 Å Cu spacer). The strong coupling strength is qualitatively understood within the framework of a combined effect of Ruderman-Kittel- Kasuya-Yosida interaction and pinhole coupling, which is evidenced by transmission electron microscopy analysis. The magnetic coupling constant decreases exponentially with increasing Cu spacer thickness, without showing an oscillatory thickness dependence. The results have implications for the design of multilayers for spintronic applications.
This paper discusses the physical nature of the optimum sheet resistance of noise suppression sheets/films based on three-dimensional (3-D) finite-element method (FEM) electromagnetic field ...simulation. Co-Al-O films with sheet resistance of10 -1 -10 5 Omega/square were deposited on top of a micro strip-line. It was revealed that inline loss generation was maximized with the film's sheet resistance of nominally 100 Omega/square, which explains well the earlier experimental results. The ratio of loss generation to the input power reached 0.96 in the experimental results and 0.97 in the simulation results at 6 GHz. A certain balance of eddy current generation and a material resistivity allowed the Co-Al-O film to dissipate the inline noise power effectively. The simulation results also showed that the inline power was not radiated from the Co-Al-O film but was lost in the film. Ferromagnetic resonance losses were found around 1-2 GHz combined with the eddy current losses. These two electric and magnetic losses enhanced total inline loss generation effectively
Posterior cortical atrophy (PCA) is characterized by bilateral parieto-occipito-temporal atrophy and hypometabolism. Neuropsychological impairments include complex visual disturbances, alexia, ...agraphia, finger agnosia, right–left disorientation and dyscalculia. A recent case study reported severe numerical deficits with some selectively preserved numerical skills in a patient affected by PCA Delazer, M., Karner, E., Zamarian, L., Donnemiller, E., & Benke, T. (2006). Number processing in posterior cortical atrophy—a neuropsycholgical case study.
Neuropsychologia. In a functional magnetic resonance imaging (fMRI) study brain activation patterns related to these selectively preserved numerical skills were analyzed. Recitation of multiplication tables and counting forward were contrasted to word recitation in a block design. Contrasts between experimental conditions and control condition yielded significant activation of inferior and medial temporal structures. Since numerical processing is generally associated with parietal activation, it was hypothesized that preserved brain structures would compensate for the functional deficits.
We have analyzed the Nojima fault NIED 1800 m drill core samples by ESR (Electron Spin Resonance) to detect seismic frictional heating events, especially during the 1995 Kobe Earthquake. Dark gray ...fault gouge with foliation >
10 cm away from the fault plane at about 1140 m in depth, which was produced by ancient fault movements, has a FMR (ferrimagnetic resonance) signal. Heating experiments show that this FMR signal is derived from ferrimagnetic trivalent ion oxides (γ-Fe
2O
3: maghemite) with imperfect crystallinity, which is produced by thermal dehydration of γ-FeOOH (lepidocrocite) or Fe(OH)
3 (limonite). The existence of the FMR signal means that dry heating such as frictional heating once occurred, and that the frictional heat temperature along the dark gray fault gouge may have risen to over 350 °C during ancient seismic fault slip. In order to detect frictional heating events in fault zones, the increase of the FMR signal and the color change of fault gouge into dark gray or black are important indexes. On the other hand, no FMR signal is detected from the fault gouges just on two fault planes at about 1140 m and 1300 m in depth, which are considered to be possible main fault planes in the 1995 Kobe Earthquake. These two fault planes may not have played an important role of fault slip in the Earthquake.
The present paper reviews recent studies on changes in body mass, body composition and rates of energy expenditure during the breeding season in the black-legged Kittiwake (
Rissa tridactyla) on ...Svalbard (79 °N). The main characteristic of the energy budget is a pronounced decrease in body mass as well as basal metabolic rate (BMR) after the eggs have hatched. While most internal organs lose mass in direct proportion to the general decrease in body mass, the liver and kidney masses decrease to a disproportionately greater extent. Since both the liver and the kidney have high intrinsic metabolic rates, these results support an earlier notion that the reduction in body mass is an adaptation to reduce maintenance costs. Alternatively, the reduced BMR is due to a decrease in energy uptake from the gastrointestinal tract, thereby ensuring that undigested food is ready to be regurgitated to the chicks. At the end of the chick-rearing period, the field metabolic rate (FMR) reaches its highest level, probably due to an increased workload associated with chick feeding. This occurs at a time of low body mass and BMR. A pronounced increase in the metabolic scope (FMR/BMR) during the latter part of the chick-rearing period demonstrates that BMR and FMR may change independently of each other and that the ratio FMR/BMR may not be a good measure of energy stress.
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