570 research outputs found
Superconductivity and the high field ordered phase in the heavy fermion compound PrOsSb
Superconductivity is observed in the filled skutterudite compound \PrOsSb{}
below a critical temperature temperature K and appears to
develop out of a nonmagnetic heavy Fermi liquid with an effective mass , where is the free electron mass.
Features associated with a cubic crystalline electric field are present in
magnetic susceptibility, specific heat, electrical resistivity, and inelastic
neutron scattering measurements, yielding a Pr energy level scheme
consisting of a nonmagnetic doublet ground state, a low lying
triplet excitied state at K, and much higher temperature
triplet and singlet excited states. Measurements also
indicate that the superconducting state is unconventional and consists of two
distinct superconducting phases. At high fields and low temperatures, an
ordered phase of magnetic or quadrupolar origin is observed, suggesting that
the superconductivity may occur in the vicinity of a magnetic or quadrupolar
quantum critical point.Comment: 11 pages, 4 figures, presented at the 3rd international symposium on
Advance Science Research (ASR 2002), JAERI Tokai, Ibaraki, Japa
Disability-specific associations with child health and functioning
This study examined the health profile of children with different types of disabilities and explored the disability-specific associations with various types of health and functioning using a large nonclinical sample of children. A cross-sectional school survey was conducted during 2016 and 2017. A total of 4114 children (aged 6–18 years) receiving primary or secondary education, or their proxy, in Hong Kong participated in the study. Disabilities were categorized as (a) physical disabilities; (b) learning and developmental disabilities; (c) intellectual disabilities; (d) internalizing disorders or mental illness; and (e) autism spectrum disorder. Health-related quality of life (QoL), sleep-related QoL, activities of daily living (ADL), emotional functioning, and social functioning were assessed and compared between children with disabilities and those without. The results showed that children with disabilities showed poorer physical functioning, health-related QoL, and emotional and social functioning than their counterparts without disabilities. Disability-specific associations with health were found: (a) physical disabilities and intellectual disabilities were associated with greater difficulties in ADL; (b) language impairment and Attention deficit/ hyperactivity disorder (ADHD) were negatively associated with sleep-related QoL; (c) all types of disabilities but hearing impairment were negatively associated with health-related QoL (HRQoL); and (d) language impairment, ADHD, internalizing disorder, as well as autism spectrum disorder were associated with greater abnormal behavioral difficulties. The findings warrant the development of tailor-made intervention programs and give insights to effective resource allocation for the children in need
Superconductivity and crystalline electric field effects in the filled skutterudite series Pr(OsRu)Sb
X-ray powder diffraction, magnetic susceptibility , and electrical
resistivity measurements were made on single crystals of the filled
skutterudite series Pr(OsRu)Sb. One end of the series
() is a heavy fermion superconductor with a superconducting critical
temperature K, while the other end () is a conventional
superconductor with K. The lattice constant decreases
approximately linearly with increasing Ru concentration . As Ru (Os) is
substituted for Os (Ru), decreases nearly linearly with substituent
concentration and exhibits a minimum with a value of K at , suggesting that the two types of superconductivity compete with one
another. Crystalline electric field (CEF) effects in and
due to the splitting of the Pr nine-fold degenerate Hund's
rule multiplet are observed throughout the series, with the splitting
between the ground state and the first excited state increasing monotonically
as increases. The fits to the and data are
consistent with a doublet ground state for all values of x,
although reasonable fits can be obtained for a ground state for
values near the end member compounds ( or ).Comment: 10 pages, 8 figures, submitted to Phys. Rev.
Humans decompose tasks by trading off utility and computational cost
Human behavior emerges from planning over elaborate decompositions of tasks
into goals, subgoals, and low-level actions. How are these decompositions
created and used? Here, we propose and evaluate a normative framework for task
decomposition based on the simple idea that people decompose tasks to reduce
the overall cost of planning while maintaining task performance. Analyzing
11,117 distinct graph-structured planning tasks, we find that our framework
justifies several existing heuristics for task decomposition and makes
predictions that can be distinguished from two alternative normative accounts.
We report a behavioral study of task decomposition () that uses 30
randomly sampled graphs, a larger and more diverse set than that of any
previous behavioral study on this topic. We find that human responses are more
consistent with our framework for task decomposition than alternative normative
accounts and are most consistent with a heuristic -- betweenness centrality --
that is justified by our approach. Taken together, our results provide new
theoretical insight into the computational principles underlying the
intelligent structuring of goal-directed behavior
Individual and joint associations of anxiety disorder and depression with cardiovascular disease:A UK Biobank prospective cohort study
BACKGROUND: Growing evidence suggests that individuals with anxiety disorder have an elevated risk of cardiovascular disease (CVD) but few studies have assessed this association independently of or jointly with depression.METHODS: We conducted a prospective cohort study using UK Biobank. Diagnoses of anxiety disorder, depression, and CVDs were ascertained through linked hospital admission and mortality data. Individual and joint associations between anxiety disorder and depression and CVD overall, as well as each of myocardial infarction, stroke/transient ischemic attack, and heart failure, were analyzed using Cox proportional hazard models and interaction tests.RESULTS: Among the 431,973 participants, the risk of CVD was higher among those who had been diagnosed with anxiety disorder only (hazard ratio [HR] 1.72; 95% confidence interval [CI] 1.32-2.24), depression only (HR 2.07; 95% CI 1.79-2.40), and both conditions (HR 2.89; 95% CI 2.03-4.11) compared to those without these conditions, respectively. There was very little evidence of multiplicative or additive interaction. Results were similar for myocardial infarction, stroke/transient ischemic attack, and heart failure.CONCLUSIONS: Having anxiety is associated with the same magnitude of increased risk of CVD among people who do not have depression and those who do. Anxiety disorder should be considered for inclusion in CVD risk prediction and stratification, in addition to depression.</p
Crystalline electric field effects in the electrical resistivity of PrOsSb
The temperature and magnetic field dependencies of the electrical
resistivity of the recently discovered heavy fermion superconductor
\PrOsSb{} have features that are associated with the splitting of the Pr
Hund's rule multiplet by the crystalline electric field (CEF). These features
are apparently due to magnetic exchange and aspherical Coulomb scattering from
the thermally populated CEF-split Pr energy levels. The data
in zero magnetic field can be described well by calculations based on CEF
theory for various ratios of magnetic exchange and aspherical Coulomb
scattering, and yield CEF parameters that are qualitatively consistent with
those previously derived from magnetic susceptibility, specific heat, and
inelastic neutron scattering measurements. Calculated isotherms for a
ground state qualitatively account for the `dome-shaped' feature
in the measured isotherms.Comment: 8 pages, 2 figures, submitted to Journal of Physics: Condensed Matte
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