1,371 research outputs found
Limb-Brightened Jet of 3C 84 Revealed by the 43-GHz Very-Long-Baseline-Array Observation
We present a study of sub-pc scale radio structure of the radio galaxy 3C
84/NGC 1275 based on the Very Long Baseline Array (VLBA) data at 43 GHz. We
discover a limb-brightening in the "restarted" jet associated with the 2005
radio outburst. In the 1990s, the jet structure was ridge-brightening rather
than limb-brightening, despite the observations being done with similar angular
resolution. This indicates that the transverse jet structure has changed
recently. This change in the morphology shows an interesting agreement with the
-ray flux increase, i.e., the -ray flux in 1990s was at least
seven times lower than the current one. One plausible explanation for the
limb-brightening is the velocity structure of the jet in the context of the
stratified jet, which is a successful scenario to explain the -ray
emission in some active galactic nuclei (AGNs). If this is the case, the change
in apparent transverse structure might be caused by the change in the
transverse velocity structure. We argue the possibility that the transition
from ridge-brightening to limb-brightening is related to the -ray time
variability on the timescale of decades. We also discuss the collimation
profile of the jet.Comment: 22 pages, 4 figures, Accepted for Publication in Ap
Microstructural evolution under low shear rates during Rheo processing of LM25 alloy
© ASM InternationalMicrostructural features of LM25 alloy processed by two different routes: (1) conventional casting, and(2)shear casting based on inclined heated surface are studied. The microstructures of the primary phase for the shear-cast samples show rosette or ellipsoidal morphologies. Heat transfer of contacting melt with the
inclined tube surface and shear stress exerted on the layers of the melt as result of gravitational force are crucial parameters for the microstructural evolution. Compared to those produced by conventional casting, shear-cast samples have a much improved tensile strength and ductility due to globular microstructure
Passion, grit and mindset in young adults: Exploring the relationship and gender differences
Publisher's version (útgefin grein)The main aim of the study was to explore the associations between passion, grit and mindset in a group of young Icelandic adults. The sample consisted of 146 participants. The eight item Passion Scale was used to assess passion, and the Grit-S scale was used to assess grit. Mindset was measured with the Theories of Intelligence Scale (TIS). The scale has 8-items.
The results show significant difference between female and male in the passion factor only, in favor of males. In addition the results indicated a significant correlation between all factors for the group as a whole; passion and grit, r = .435; passion and mindset, r = .260; grit and mindset, r = .274. The results for the gender separate indicate a same pattern for the females, significant correlation between all the factors; passion – grit, r = .382, passion-mindset, r = . 299 and grit-mindset, r = .356. For the males the pattern was different. Significant correlation was between passion-grit, r = .500 and for passion-mindset r =.260. For grit-mindset there was not significant correlation r = .215. The results indicate gender differences in associations between passion, grit and mindset.Peer reviewe
Extremely Large and Anisotropic Upper Critical Field and the Ferromagnetic Instability in UCoGe
Magnetoresistivity measurements with fine tuning of the field direction on
high quality single crystals of the ferromagnetic superconductor UCoGe show
anomalous anisotropy of the upper critical field H_c2. H_c2 for H // b-axis
(H_c2^b) in the orthorhombic crystal structure is strongly enhanced with
decreasing temperature with an S-shape and reaches nearly 20 T at 0 K. The
temperature dependence of H_c2^a shows upward curvature with a low temperature
value exceeding 30 T, while H_c2^c at 0 K is very small (~ 0.6 T). Contrary to
conventional ferromagnets, the decrease of the Curie temperature with
increasing field for H // b-axis marked by an enhancement of the effective mass
of the conduction electrons appears to be the origin of the S-shaped H_c2^b
curve. These results indicate that the field-induced ferromagnetic instability
or magnetic quantum criticality reinforces superconductivity.Comment: 5 pages, 4 figures, accepted for publication in J. Phys. Soc. Jp
The passion scale: Aspects of reliability and validity of a new 8-item scale assessing passion.
Publisher's version (útgefin grein)In this article, the psychometric properties of a new scale aimed at quantifying passion are explored, i.e. passion related to becoming good or achieving in some area/theme/skill.
The Passion Scale was designed to be quantitative, simple to administer, applicable for large-group testing, and reliable in monitoring passion.
A total of 126 participants between 18 and 47 years of age (mean age = 21.65, SD = 3.45) completed an assessment of Passion Scale, enabling us to investigate its feasibility, internal consistency, construct validity and test-retest reliability.
Feasibility: The overall pattern of results suggest that the scale for passion presented here is applicable for the age studied (18-47).
Internal consistency: All individual item scores correlated positively with the total score, with correlations ranging from 0.51 to 0.69. The Cronbach's alpha value for the standardized items was 0.86.
Construct validity: Pearson correlations coefficient between total score passion scale and Grit-S scale were 0.39 for adults, mean age 21.23 (SD = 3.45) (N = 107).
Test-retest reliability: Intraclass correlation coefficient (ICCs) between test and retest scores for the total score was 0.92.
These promising results warrant further development of the passion scale, including normalization based on a large, representative sample."Peer Reviewed
Unique Spin Dynamics and Unconventional Superconductivity in the Layered Heavy Fermion Compound CeIrIn_5:NQR Evidence
We report measurements of the ^{115}In nuclear spin-lattice relaxation rate
(1/T_1) between T=0.09 K and 100 K in the new heavy fermion (HF) compound
CeIrIn_5. At 0.4 K < T < 100 K, 1/T_1 is strongly T-dependent, which indicates
that CeIrIn_5 is much more itinerant than known Ce-based HFs. We find that
1/T_1T, subtracting that for LaIrIn_5, follows a 1/(T+\theta)^{3/4} variation
with \theta=8 K. We argue that this novel feature points to anisotropic, due to
a layered crystal structure, spin fluctuations near a magnetic ordering. The
bulk superconductivity sets in at 0.40 K below which the coherence peak is
absent and 1/T_1 follows a T^3 variation, which suggests unconventional
superconductivity with line-node gap.Comment: minor changes, appeared in PRL (4 pages, 4 figures
Gapless Magnetic and Quasiparticle Excitations due to the Coexistence of Antiferromagnetism and Superconductivity in CeRhIn : A study of In-NQR under Pressure
We report systematic measurements of ac-susceptibility,
nuclear-quadrupole-resonance spectrum, and nuclear-spin-lattice-relaxation time
() on the pressure ()- induced heavy-fermion (HF) superconductor
CeRhIn. The temperature () dependence of at = 1.6 GPa has
revealed that antiferromagnetism (AFM) and superconductivity (SC) coexist
microscopically, exhibiting the respective transition at K and
= 0.9 K. It is demonstrated that SC does not yield any trace of gap
opening in low-lying excitations below K, but K, followed by a = const law. These results point to the
unconventional characteristics of SC coexisting with AFM. We highlight that
both of the results deserve theoretical work on the gapless nature in low-lying
excitation spectrum due to the coexistence of AFM and SC and the lack of the
mean-field regime below K.Comment: 4pages,5figures,revised versio
Perturbation theory for the one-dimensional optical polaron
The one-dimensional optical polaron is treated on the basis of the
perturbation theory in the weak coupling limit. A special matrix diagrammatic
technique is developed. It is shown how to evaluate all terms of the
perturbation theory for the ground-state energy of a polaron to any order by
means of this technique. The ground-state energy is calculated up to the eighth
order of the perturbation theory. The effective mass of an electron is obtained
up to the sixth order of the perturbation theory. The radius of convergence of
the obtained series is estimated. The obtained results are compared with the
results from the Feynman polaron theory.Comment: 9 pages, 2 figures, RevTeX, to be published in Phys. Rev. B (2001)
Ap
On the origin of the zero-resistance anomaly in heavy fermion superconducting Ir: a clue from magnetic field and Rh-doping studies
We present the results of the specific heat and AC magnetic susceptibility
measurements of for x from 0 to 0.5. As x is increased
from 0 both quantities reflect the competition between two effects. The first
is a suppression of superconductivity below the bulk transition temperature of
T K, which is due to the pair breaking effect of Rh impurities. The
second is an increase in the volume fraction of the superconducting regions
above T, which we attribute to defect-induced strain. Analysis of the H-T
phase diagram for CeIrInobtained from the bulk probes and resistance
measurements points to the filamentary origin of the inhomogeneous
superconductivity at T K, where the resistance drops to
zero. The identical anisotropies in the magnetic field dependence of the
specific heat and the resistance anomalies in CeIrIn indicate that the
filamentary superconductivity is intrinsic, involving electrons from the part
of the Fermi surface responsible for bulk superconductivity.Comment: 4 page
- …