256 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
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
Heavy Fermion Behavior, Crystalline Electric Field Effects, and Weak Ferromagnetism in SmOs_{4}Sb_{12}
The filled skutterudite compound SmOs_{4}Sb_{12} was prepared in single
crystal form and characterized. The SmOs_{4}Sb_{12} crystals have the
LaFe_{4}P_{12}-type structure with lattice parameter a = 9.3085 Angstroms.
Specific heat measurements indicate a large electronic specific heat
coefficient of ~880 mJ/mol K^{2}, from which an enhanced effective mass m^{*} ~
170 m_{e} is estimated. The specific heat data also suggest crystalline
electric field (CEF) splitting of the Sm^{3+} J = 5/2 multiplet into a
Gamma_{7} doublet ground state and a Gamma_{8} quartet excited state separated
by 37 K. Electrical resistivity rho(T) measurements reveal a decrease in rho(T)
below ~50 K that is consistent with CEF splitting of ~33 K between a Gamma_(7)
doublet ground state and Gamma_{8} quartet excited state. Specific heat and
magnetic susceptibility measurements display a possible weak ferromagnetic
transition at ~2.6 K, which could be an intrinsic property of SmOs_4Sb_{12} or
possibly due to an unknown impurity phase.Comment: 24 pages, 11 Postscript figures, to be published in Physical Review
A Longitudinal Study of the Relation between Childhood Activities and Psychosocial Adjustment in Early Adolescence
Background: Although an increasing body of research shows that excessive screen time could impair brain development, whereas non-screen recreational activities can promote the development of adaptive emotion regulation and social skills, there is a lack of comparative research on this topic. Hence, this study examined whether and to what extent the frequency of early-life activities predicted later externalizing and internalizing problems. Methods: In 2012/13, we recruited Kindergarten 3 (K3) students from randomly selected kindergartens in two districts of Hong Kong and collected parent-report data on childrenâs screen activities and parentâchild activities. In 2018/19, we re-surveyed the parents of 323 students (aged 11 to 13 years) with question items regarding their childrenâs externalizing and internalizing symptoms in early adolescence. Linear regression analyses were conducted to examine the associations between childhood activities and psychosocial problems in early adolescence. Results: Early-life parentâchild activities (ÎČ = â0.14, p = 0.012) and child-alone screen use duration (ÎČ = 0.15, p = 0.007) independently predicted externalizing problems in early adolescence. Their associations with video game exposure (ÎČ = 0.19, p = 0.004) and non-screen recreational parentâchild activities (ÎČ = â0.14, p = 0.004) were particularly strong. Conclusions: Parentâchild play time is important for healthy psychosocial development. More efforts should be directed to urge parents and caregivers to replace child-alone screen time with parentâchild play time
Associations of family meals with adolescent perception of family relationship and compliance with parental guidance in Hong Kong: results of a representative cross-sectional survey
Family meals are beneficial for adolescent development, but evidence from Chinese populations has been limited. This study aimed to examine the associations between family meal frequency and adolescent perception of family relationship and compliance with parental guidance in Hong Kong. During the period from October to December 2016, a stratified random sample of 3359 students were recruited from 25 secondary schools in Hong Kong. Students completed questionnaires about family characteristics, relationship quality, and meal frequency by paper-and-pencil in class. Multiple regression analyses were conducted to examine the associations between family meal frequency and perceived family relationship and compliance with parental guidance overall and by subgroups. After adjusting for sociodemographic and school confounders, family breakfast and dinner frequency were significantly associated with adolescent compliance (breakfast: B = 0.07, p < 0.001; dinner: B 0.07, p < 0.001) and perception of family relationship (breakfast: B = 0.10, p < 0.001; dinner: B = 0.25, p < 0.001). Risk factors for infrequent family meals included older age, not born in Hong Kong, less educated fathers, and unmarried parents. Our findings support the associations of regular family meals with adolescent perception of high family bond and compliance with parental guidance. Interventions are needed to enhance quality family meal interactions in disadvantaged families
Quantification of injury burden using multiple data sources: a longitudinal study
Quantification of injury burden is vital for injury prevention, as it provides a guide for setting policies and priorities. This study generated a set of Hong Kong specific disability weights (DWs) derived from patient experiences and hospital records. Patients were recruited from the Accident and Emergency Department (AED) of three major trauma centers in Hong Kong between September 2014 and December 2015 and subsequently interviewed with a focus on health-related quality of life at most three times over a 12-month period. These patient-reported data were then used for estimation of DWs. The burden of injury was determined using the mortality and inpatient data from 2001 to 2012 and then compared with those reported in the UK Burden of Injury (UKBOI) and global burden of diseases (GBD) studies. There were 22,856 mortality cases and 817,953 morbidity cases caused by injuries, in total contributing to 1,027,641 disability-adjusted life years (DALYs) in the 12-year study timeframe. Estimates for DALYs per 100,000 in Hong Kong amounted to 1192, compared with 2924 in UKBOI and 3459 in GBD. Our findings support the use of multiple data sources including patient-reported data and hospital records for estimation of injury burden
Smartphone and medical related App use among medical students and junior doctors in the United Kingdom (UK): a regional survey
Background: Smartphone usage has spread to many settings including that of healthcare with numerous potential
and realised benefits. The ability to download custom-built software applications (apps) has created a new wealth
of clinical resources available to healthcare staff, providing evidence-based decisional tools to reduce medical errors.
Previous literature has examined how smartphones can be utilised by both medical student and doctor
populations, to enhance educational and workplace activities, with the potential to improve overall patient care.
However, this literature has not examined smartphone acceptance and patterns of medical app usage within the
student and junior doctor populations.
Methods: An online survey of medical student and foundation level junior doctor cohorts was undertaken within
one United Kingdom healthcare region. Participants were asked whether they owned a Smartphone and if they
used apps on their Smartphones to support their education and practice activities. Frequency of use and type of
app used was also investigated. Open response questions explored participantsâ views on apps that were desired or
recommended and the characteristics of apps that were useful.
Results: 257 medical students and 131 junior doctors responded, equating to a response rate of 15.0% and 21.8%
respectively. 79.0% (n=203/257) of medical students and 74.8% (n=98/131) of junior doctors owned a smartphone,
with 56.6% (n=115/203) of students and 68.4% (n=67/98) of doctors owning an iPhone.
The majority of students and doctors owned 1â5 medical related applications, with very few owning more than 10,
and iPhone owners significantly more likely to own apps (Chi sq, p<0.001). Both populations showed similar trends
of app usage of several times a day. Over 24hours apps were used for between 1â30 minutes for students and
1â20 minutes for doctors, students used disease diagnosis/management and drug reference apps, with doctors
favouring clinical score/calculator apps.
Conclusions: This study found a high level of smartphone ownership and usage among medical students and
junior doctors. Both groups endorse the development of more apps to support their education and clinical
practice
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Multiple ordered phases in the filled skutterudite compound PrOs4As12
Magnetization, specific heat, and electrical resistivity measurements were made on single crystals of the filled skutterudite compound PrOs{sub 4}As{sub 12}. Specific heat measurements indicate an electronic specific heat coefficient {gamma} {approx} 50-200 mJ/mol K{sup 2} at temperatures 10 K {le} T {le} 18 K, and {approx} 1 J/mol K{sup 2} for t {le} 1.6 K. Magnetization, specific heat, and electrical resistivity measurements reveal the presence of two, or possibly three, ordered phases at temperatures below {approx} 2.3 K and in fields below {approx} 3 T. The low temperature phase displays antiferromagnetic characteristics, while the nature of the ordering in the other phase(s) has yet to be determined
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic Survey
The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic
data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data
release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median
z=0.52), 102,100 new quasar spectra (median z=2.32), and 90,897 new stellar
spectra, along with the data presented in previous data releases. These spectra
were obtained with the new BOSS spectrograph and were taken between 2009
December and 2011 July. In addition, the stellar parameters pipeline, which
determines radial velocities, surface temperatures, surface gravities, and
metallicities of stars, has been updated and refined with improvements in
temperature estimates for stars with T_eff<5000 K and in metallicity estimates
for stars with [Fe/H]>-0.5. DR9 includes new stellar parameters for all stars
presented in DR8, including stars from SDSS-I and II, as well as those observed
as part of the SDSS-III Sloan Extension for Galactic Understanding and
Exploration-2 (SEGUE-2).
The astrometry error introduced in the DR8 imaging catalogs has been
corrected in the DR9 data products. The next data release for SDSS-III will be
in Summer 2013, which will present the first data from the Apache Point
Observatory Galactic Evolution Experiment (APOGEE) along with another year of
data from BOSS, followed by the final SDSS-III data release in December 2014.Comment: 9 figures; 2 tables. Submitted to ApJS. DR9 is available at
http://www.sdss3.org/dr
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