907 research outputs found
Impact of gender and generational differences in work values and attitudes in an Arab culture
In this article, the work values and attitudes of 241 nationals from the United Arab Emirates are examined. Specifically, we assessed the impact of generational membership and gender on the Islamic work ethic, individualism, attitudes toward women at work, and perceptions of the utility of wasta. Results suggest that values and attitudes held by people in the Middle East are changing on the one hand (e.g., individualism) but are also deeply held on the other (e.g., the Islamic work ethic). Results also suggest that the perceptions about the utility of wasta differ across generations. The implications of these findings and suggestions for future research are discussed. © 2006 Wiley Periodicals, Inc
Text messaging and brief phone calls for weight loss in overweight and obese English- and Spanish-speaking adults: A 1-year, parallel-group, randomized controlled trial.
BACKGROUND:Weight loss interventions based solely on text messaging (short message service [SMS]) have been shown to be modestly effective for short periods of time and in some populations, but limited evidence is available for positive longer-term outcomes and for efficacy in Hispanic populations. Also, little is known about the comparative efficacy of weight loss interventions that use SMS coupled with brief, technology-mediated contact with health coaches, an important issue when considering the scalability and cost of interventions. We examined the efficacy of a 1-year intervention designed to reduce weight among overweight and obese English- and Spanish-speaking adults via SMS alone (ConTxt) or in combination with brief, monthly health-coaching calls. ConTxt offered 2-4 SMS/day that were personalized, tailored, and interactive. Content was theory- and evidence-based and focused on reducing energy intake and increasing energy expenditure. Monthly health-coaching calls (5-10 minutes' duration) focused on goal-setting, identifying barriers to achieving goals, and self-monitoring. METHODS AND FINDINGS:English- and Spanish-speaking adults were recruited from October 2011 to March 2013. A total of 298 overweight (body mass index [BMI] 27.0 to 39.9 kg/m2) adults (aged 21-60 years; 77% female; 41% Hispanic; 21% primarily Spanish speaking; 44% college graduates or higher; 22% unemployed) were randomly assigned (1:1) to receive either ConTxt only (n = 101), ConTxt plus health-coaching calls (n = 96), or standard print materials on weight reduction (control group, n = 101). We used computer-based permuted-block randomization with block sizes of three or six, stratified by sex and Spanish-speaking status. Participants, study staff, and investigators were masked until the intervention was assigned. The primary outcome was objectively measured percent of weight loss from baseline at 12 months. Differences between groups were evaluated using linear mixed-effects regression within an intention-to-treat framework. A total of 261 (87.2%) and 253 (84.9%) participants completed 6- and 12-month visits, respectively. Loss to follow-up did not differ by study group. Mean (95% confidence intervals [CIs]) percent weight loss at 12 months was -0.61 (-1.99 to 0.77) in the control group, -1.68 (-3.08 to -0.27) in ConTxt only, and -3.63 (-5.05 to -2.81) in ConTxt plus health-coaching calls. At 12 months, mean (95% CI) percent weight loss, adjusted for baseline BMI, was significantly different between ConTxt plus health-coaching calls and the control group (-3.0 [-4.99 to -1.04], p = 0.003) but not between the ConTxt-only and the control group (-1.07 [-3.05 to 0.92], p = 0.291). Differences between ConTxt plus health-coaching calls and ConTxt only were not significant (-1.95 [-3.96 to 0.06], p = 0.057). These findings were consistent across other weight-related secondary outcomes, including changes in absolute weight, BMI, and percent body fat at 12 months. Exploratory subgroup analyses suggested that Spanish speakers responded more favorably to ConTxt plus health-coaching calls than English speakers (Spanish contrast: -7.90 [-11.94 to -3.86], p < 0.001; English contrast: -1.82 [-4.03 to 0.39], p = 0.107). Limitations include the unblinded delivery of the intervention and recruitment of a predominantly female sample from a single site. CONCLUSIONS:A 1-year intervention that delivered theory- and evidence-based weight loss content via daily personalized, tailored, and interactive SMS was most effective when combined with brief, monthly phone calls. TRIAL REGISTRATION:ClinicalTrials.gov NCT01171586
The (un)resolved X-ray background in the Lockman Hole
Most of the soft and a growing fraction of the harder X-ray background has
been resolved into emission from point sources, yet the resolved fraction above
7 keV has only been poorly constrained. We use ~700 ks of XMM-Newton
observations of the Lockman Hole and a photometric approach to estimate the
total flux attributable to resolved sources in a number of different energy
bands. We find the resolved fraction of the X-ray background to be ~90 per cent
below 2 keV but it decreases rapidly at higher energies with the resolved
fraction above ~7 keV being only ~50 per cent. The integrated X-ray spectrum
from detected sources has a slope of Gamma~1.75, much softer than the Gamma=1.4
of the total background spectrum. The unresolved background component has the
spectral signature of highly obscured AGN.Comment: 6 pages, 6 figures, MNRAS Letters, in press, changed to reflect
accepted versio
Effect of an Electron-phonon Interaction on the One-electron Spectral Weight of a d-wave Superconductor
We analyze the effects of an electron-phonon interaction on the one-electron
spectral weight A(k,omega) of a d_{x^2-y^2} superconductor. We study the case
of an Einstein phonon mode with various momentum-dependent electron-phonon
couplings and compare the structure produced in A(k,omega) with that obtained
from coupling to the magnetic pi-resonant mode. We find that if the strength of
the interactions are adjusted to give the same renormalization at the nodal
point, the differences in A(k,omega) are generally small but possibly
observable near k=(pi,0).Comment: 10 pages, 14 figures (color versions of Figs. 2,4,10,11,12 available
upon request
Isotope Effect for the Penetration Depth in Superconductors
We show that various factors can lead to an isotopic dependence of the
penetration depth . Non-adiabaticity (Jahn-Teller crossing) leads to
the isotope effect of the charge carrier concentration and, consequently,
of in doped superconductors such as the cuprates. A general equation
relating the isotope coefficients of and of is presented for
London superconductors. We further show that the presence of magnetic
impurities or a proximity contact also lead to an isotopic dependence of
; the isotope coefficient turns out to be temperature dependent,
, in these cases. The existence of the isotope effect for the
penetration depth is predicted for conventional as well as for high-temperature
superconductors. Various experiments are proposed and/or discussed.Comment: 11 pages, 8 figures, accepted for publication in Phys. Rev.
XMM-Newton observations of Extremely Red Objects and the link with luminous, X-ray obscured Quasars
We present the results of a deep (about 80 ks) XMM-Newton survey of the
largest sample of near-infrared selected Extremely Red Objects (R-K>5)
available to date to K_S< 19.2. At the relatively bright X-ray fluxes (F_{2-10
keV}> 4x10^{-15} cgs) and near-infrared magnitude probed by the present
observations, the fraction of AGN (i.e., X-ray detected) among the ERO
population is small (~3.5%); conversely, the fraction of EROs among hard X-ray
selected sources is much higher (~20%). The X-ray properties of EROs detected
in our XMM-Newton observation indicate absorption in excess of 10^{22} cm^{-2}
in a large fraction of them. We have also considered additional samples of
X-ray detected EROs available in the literature. X-ray spectral analysis of the
highest S/N sources unambiguously indicates that large columns of cold gas
(even >10^{23} cm^{-2}) are the rule rather than the exception. The X-ray,
optical, and near-infrared properties of those X-ray selected EROs with a
spectroscopic or photometric redshift nicely match those expected for quasars
2, the high-luminosity, high-redshift obscured AGNs predicted in baseline XRB
synthesis models. A close correlation is detected between X- and K-band fluxes.
For the AGN EROs this is consistent, under reasonable assumptions, with the
relation established locally between the host galaxies and their central black
holes. This suggest that the majority of EROs are powered by massive black
holes accreting, on average, at about 0.03-0.1 of the Eddington limit.Comment: 33 pages, 10 figures, to appear in A&
Magnetic polarons in weakly doped high-Tc superconductors
We consider a spin Hamiltonian describing - exchange interactions
between localized spins of a finite antiferromagnet as well as -
interactions between a conducting hole () and localized spins. The spin
Hamiltonian is solved numerically with use of Lanczos method of
diagonalization. We conclude that - exchange interaction leads to
localization of magnetic polarons. Quantum fluctuations of the antiferromagnet
strengthen this effect and make the formation of polarons localized in one site
possible even for weak - coupling. Total energy calculations, including
the kinetic energy, do not change essentially the phase diagram of magnetic
polarons formation. For parameters reasonable for high- superconductors
either a polaron localized on one lattice cell or a small ferron can form. For
reasonable values of the dielectric function and - coupling, the
contributions of magnetic and phonon terms in the formation of a polaron in
weakly doped high- materials are comparable.Comment: revised, revtex-4, 12 pages 8 eps figure
"Pair" Fermi contour and repulsion-induced superconductivity in cuprates
The pairing of charge carriers with large pair momentum is considered in
connection with high-temperature superconductivity of cuprate compounds. The
possibility of pairing arises due to some essential features of
quasi-two-dimensional electronic structure of cuprates: (i) The Fermi contour
with strong nesting features; (ii) The presence of extended saddle point near
the Fermi level; (iii) The existence of some ordered state (for example,
antiferromagnetic) close to the superconducting one as a reason for an
appearing of "pair" Fermi contour resulting from carrier redistribution in
momentum space. In an extended vicinity of the saddle point, momentum space has
hyperbolic (pseudoeuclidean) metrics, therefore, the principal values of
two-dimensional reciprocal reduced effective mass tensor have unlike signs.
Rearrangement of holes in momentum space results in a rise of "pair" Fermi
contour which may be defined as zero-energy line for relative motion of the
pair. The superconducting gap arises just on this line. Pair Fermi contour
formation inside the region of momentum space with hyperbolic metrics results
in not only superconducting pairing but in a rise of quasi-stationary state in
the relative motion of the pair. Such a state has rather small decay and may be
related to the pseudogap regime of underdoped cuprates. It is concluded that
the pairing in cuprates may be due to screened Coulomb repulsion. In this case,
the superconducting energy gap in hole-doped cuprates exists in the region of
hole concentration which is bounded both above and below. The superconducting
state with positive condensation energy exists in more narrow range of doping
level inside this region. Such hole concentration dependence correlates with
typical phase diagram of cuprates.Comment: 23 pages, 11 figures. Submitted to Phys. Rev.
Interplay of Electron-Phonon Interaction and Electron Correlation in High Temperature Superconductivity
We study the electron-phonon interaction in the strongly correlated
superconducting cuprates. Two types of the electron-phonon interactions are
introduced in the model; the diagonal and off-diagonal interactions which
modify the formation energy of the Zhang-Rice singlet and its transfer
integral, respectively. The characteristic phonon-momentum and
electron-momentum dependence resulted from the off-diagonal coupling
can explain a variety of experiments. The vertex correction for the
electron-phonon interaction is formulated in the SU(2) slave-boson theory by
taking into account the collective modes in the superconducting ground states.
It is shown that the vertex correction enhances the attractive potential for
the d-wave paring mediated by phonon with around
which corresponds to the half-breathing mode of the oxygen
motion.Comment: 14 pages, 13 figure
The Feeling of Numbers: emotions in everyday engagements with data and their visualisation
This paper highlights the role that emotions play in engagements with data and their visualisation. To date, the relationship between data and emotions has rarely been noted, in part because data studies have not attended to everyday engagements with data. We draw on an empirical study to show a wide range of emotional engagements with diverse aspects of data and their visualisation, and so demonstrate the importance of emotions as vital components of making sense of data. We nuance the argument that regimes of datafication, in which numbers, metrics and statistics dominate, are characterised by a renewed faith in objectivity and rationality, arguing that in datafied times, it is not only numbers but also the feeling of numbers that is important. We build on the sociology of a) emotions and b) the everyday to do this, and in so doing, we contribute to the development of a sociology of data
- âŠ