7,453 research outputs found

    The effects of a therapy dog vs mindfulness vs a student advisor on student anxiety and well-being

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    There are growing concerns about the psychological well-being of university students; both in the UK and globally. In light of emerging research on the benefits of therapy dogs for student well-being, this study aimed to compare the use of therapy dogs to more conventional methods for improving students’ well-being. 94 university students were randomly assigned to one of three 30-minute treatment sessions: dog therapy, mindfulness, or the control group who were given the university’s standard treatment – a session with a student well-being adviser. All participants completed an anxiety scale and a mood scale, both immediately before and immediately after their allocated session. The results showed that whilst all three groups showed a significant decrease in anxiety after their allocated treatment, only the dog therapy and mindfulness groups’ anxiety levels dropped to at or below normal levels. Both the dog therapy and mindfulness groups reported post-treatment anxiety levels which were significantly lower than those of the controls. The dog therapy and mindfulness groups’ mood also showed a significant improvement after treatment whereas the control group’s did not. The findings of this study therefore suggest that the use of therapy dogs is as effective as mindfulness in reducing students’ anxiety and improving their well-being. However, more research investigating the use of multiple treatment sessions and comparing the more long-term effects of the two treatments are recommended

    Magnetotransport properties of a magnetically modulated two-dimensional electron gas with the spin-orbit interaction

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    We study the electrical transport properties of a two-dimensional electron gas with the Rashba spin-orbit interaction in presence of a constant perpendicular magnetic field (B0z^)(B_0 \hat z) which is weakly modulated by B1=B1cos(qx)z^{\bf B_1} = B_1 \cos (q x) \hat z, where B1B0B_1 \ll B_0 and q=2π/aq = 2 \pi/a with aa is the modulation period. We obtain the analytical expressions of the diffusive conductivities for spin-up and spin-down electrons. The conductivities for spin-up and spin-down electrons oscillate with different frequencies and produce beating patterns in the amplitude of the Weiss and Shubnikov-de Haas oscillations. We show that the Rashba strength can be determined by analyzing the beating pattern in the Weiss oscillation. We find a simple equation which determines the Rashba spin-orbit interaction strength if the number of Weiss oscillations between any two successive nodes is known from the experiment. We compare our results with the electrically modulated 2DEG with the Rashba interaction. For completeness, we also study the beating pattern formation in the collisional and the Hall conductivities.Comment: 11 pages, 5 figures, re-written with new result

    Clear Experimental Signature of Charge-Orbital density wave in Nd1x_{1-x}Ca1+x_{1+x}MnO4_{4}

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    Single Crystals of Nd1x_{1-x}Ca1+x_{1+x}MnO4_{4} have been prepared by the travelling floating-zone method, and possible evidence of a charge -orbital density wave in this material presented earlier [PRB68,092405 (2003)] using High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In the current note we present direct evidence of charge-orbital ordering in this material using heat capacity measurements. Our heat capacity measurements indicate a clear transition consistent with prior observation. We find two main transitions, one at temperature TH=310314T_{_H}=310-314 K, and other at TA=143T_{_A}=143 K. In addition, we may also conclude that there is a strong electron-phonon coupling in this material.Comment: 7 pages, 8 figure

    Doping Dependence of Thermal Oxidation on n-type 4H-SiC

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    The doping dependence of dry thermal oxidation rates in n-type 4H-SiC was investigated. The oxidation was performed in the temperature range 1000C to 1200C for samples with nitrogen doping in the range of 6.5e15/cm3 to 9.3e18/cm3, showing a clear doping dependence. Samples with higher doping concentrations displayed higher oxidation rates. The results were interpreted using a modified Deal-Grove model. Linear and parabolic rate constants and activation energies were extracted. Increasing nitrogen led to an increase in linear rate constant pre-exponential factor from 10-6m/s to 10-2m/s and the parabolic rate constant pre-exponential factor from 10e9m2/s to 10e6m2/s. The increase in linear rate constant was attributed to defects from doping-induced lattice mismatch, which tend to be more reactive than bulk crystal regions. The increase in the diffusion-limited parabolic rate constant was attributed to degradation in oxide quality originating from the doping-induced lattice mismatch. This degradation was confirmed by the observation of a decrease in optical density of the grown oxide films from 1.4 to 1.24. The linear activation energy varied from 1.6eV to 2.8eV, while the parabolic activation energy varied from 2.7eV to 3.3eV, increasing with doping concentration. These increased activation energies were attributed to higher nitrogen content, leading to an increase in effective bond energy stemming from the difference in C-Si (2.82eV) and Si-N (4.26eV) binding energies. This work provides crucial information in the engineering of SiO2 dielectrics for SiC MOS structures, which typically involve regions of very different doping concentrations, and suggests that thermal oxidation at high doping concentrations in SiC may be defect mediated.Comment: 13 pages. 9 figures, accepted as a transiction in IEEE electron device. TED MS#8035

    A Double Inverted F-Shape Patch Antenna for Dual-Band Operation

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    A double inverted F-shape patch antenna is presented for dual-band operation. The proposed antenna is comprised of circular and rectangular slots on a printed circuit board of 40 mm × 40 mm × 1.6 mm with a 50 Ω microstrip transmission line. Commercially available high frequency structural simulator (HFSS) based on the finite element method (FEM) has been adopted in this investigation. It has a measured impedance bandwidths (2 : 1 VSWR) of 18.53% on the lower band and 7.8% on the upper band, respectively. It has achieved stable radiation efficiencies of 79.76% and 80.36% with average gains of 7.82 dBi and 5.66 dBi in the operating frequency bands. Moreover, numerical simulations have been indicated as an important uniformity with measured results

    Macroscopic quantum tunneling and phase diffusion in a La2x_{2-x}Srx_xCuO4_4 intrinsic Josephson junction stack

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    We performed measurements of switching current distribution in a submicron La2x_{2-x}Srx_xCuO4_4 (LSCO) intrinsic Josephson junction (IJJ) stack in a wide temperature range. The escape rate saturates below approximately 2\,K, indicating that the escape event is dominated by a macroscopic quantum tunneling (MQT) process with a crossover temperature T2T^{*}\approx2\,K. We applied the theory of MQT for IJJ stacks, taking into account dissipation and the phase re-trapping effect in the LSCO IJJ stack. The theory is in good agreement with the experiment both in the MQT and in the thermal activation regimes.Comment: 9 pages, 7 figure

    Temperature Dependent Polarized XANES Spectra for Zn-doped LSCO system

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    The cuprates seem to exhibit statistics, dimensionality and phase transitions in novel ways. The nature of excitations [i.e. quasiparticle or collective], spin-charge separation, stripes [static and dynamics], inhomogeneities, psuedogap, effect of impurity dopings [e.g. Zn, Ni] and any other phenomenon in these materials must be consistently understood. Zn-doped LSCO single crystal were grown by TSFZ technique. Temperature dependent Polarized XANES [near edge local structure] spectra were measured at the BL13-B1 [Photon Factory] in the Flourescence mode from 10 K to 300 K. Since both stripes and nonmagnetic Zn impurities substituted for Cu give rise to inhomogeneous charge and spin distribution it is interesting to understand the interplay of Zn impurities and stripes. To understand these points we have used Zn-doping and some of the results obtained are as follows: The spectra show a strong dependence with respect to the polarization angle, θ\theta, as is evident at any temperature by comparing the spectra where the electric field vector is parallel with ab-plane to the one where it is parallel to the c-axis. By using the XANES [temperature] difference spectra we have determined T* [experimentally we find, T* \approx 160-170 K] for this sample. The XANES difference spectra shows that the changes in XANES features are larger in the ab-plane than the c-axis, this trend is expected since zinc is doped in the ab-plane at the copper site. Our study also complements the results in literature namely that zinc doping does not affect the c-axis transport.Comment: To appear in Physica C [ISS2001 Special Issue], related talk presented at ISS2001 as PC-16, 10 pages revtex and 7 pages of figures (pdf

    Identifying the sources of intestinal colonization with extended-spectrum beta-lactamase-producing Escherichia coli in healthy infants in the community

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    The prevalence of fecal colonization with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-Ec) among children in low- and middle-income countries is alarmingly high. This study aimed to identify the sources of ESBL-Ec colonization in children < 1 year old through comparative analysis of E. coli isolates from child stool, child's mother stool, and point-of-use drinking water from 46 rural households in Bangladesh. The pairwise similarity in antibiotic susceptibility of E. coli from all three sources was evaluated, followed by phylogenetic clustering using enterobacterial repetitive intergenic consensus polymerase chain reaction and whole-genome sequence analysis of the isolates. Matching antibiotic susceptibility and enterobacterial repetitive intergenic consensus polymerase chain reaction patterns were found among ESBL-Ec isolates from child-mother dyads of 24 and 11 households, respectively, from child-water dyads of 5 and 4 households, respectively, and from child-mother-water triads of 3 and 4 households, respectively. Whole-genome sequence analysis of 30 isolates from 10 households revealed that ESBL-Ec from children in five households (50%) was clonally related to ESBL-Ec either from their mothers (2 households), drinking water sources (2 households), or both mother and drinking-water sources (1 household) based on serotype, phylogroup, sequence type, antibiotic resistance genes, mobile genetic elements, core single-nucleotide polymorphisms, and whole-genome multilocus sequence typing. Overall, this study provides empirical evidence that ESBL-Ec colonization in children is linked to the colonization status of mothers and exposure to the household environments contaminated with ESBL-Ec. Interventions such as improved hygiene practices and a safe drinking water supply may help reduce the transmission of ESBL-Ec at the household level
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