4,010 research outputs found
Facial recognition during early motherhood: Investigating the persistence of age and affect biases
Converging evidence demonstrates increased levels of sensitivity to infant faces in mothers. This may be reflective of a series of psychological and neurobiological changes that occur in the transition to, and during early, parenthood for the purpose of appropriate caregiving; however, this enhanced infant facial recognition is in contrast with the general adult literature regarding facial processing. In the current study, we aimed to replicate a prior study of emotion facial recognition in pregnant women in a sample of mothers with children under a year old, utilizing a paradigm in which adult and infant faces gradually changed from neutral expressions to either happy or sad expressions. Mothers were faster at the recognition of adult faces in comparison to infant faces, and were also faster at happy faces in comparison to sad faces. Results are discussed in context of the current processing literature regarding the perinatal period, and implications for the persistence of the own-age bias and happy face advantage are considered
Here's looking at you, kid: attention to infant emotional faces in mothers and non-mothers.
Infant facial cues play a critical role in eliciting care and nurturance from an adult caregiver. Using an attentional capture paradigm we investigated attentional processing of adult and infant emotional facial expressions in a sample of mothers (n = 29) and non-mothers (n = 37) to determine whether infant faces were associated with greater task interference. Responses to infant target stimuli were slower than adult target stimuli in both groups. This effect was modulated by parental status, such that mothers compared to non-mothers showed longer response times to infant compared to adult faces. Both groups also responded more slowly to emotional faces, an effect that was more marked for infant emotional faces. Finally, it was found that greater levels of mothers' self-reported parental distress was associated with less task interference when processing infant faces. These findings indicate that for adult women, infant faces in general and emotional infant faces in particular, preferentially engage attention compared to adult faces. However, for mothers, infant faces appear to be more salient in general. Therefore, infant faces may constitute a special class of social stimuli. We suggest that alterations in attentional processing in motherhood may constitute an adaptive behavioural change associated with becoming a parent
Monte Carlo Determination of Multiple Extremal Eigenpairs
We present a Monte Carlo algorithm that allows the simultaneous determination
of a few extremal eigenpairs of a very large matrix without the need to compute
the inner product of two vectors or store all the components of any one vector.
The new algorithm, a Monte Carlo implementation of a deterministic one we
recently benchmarked, is an extension of the power method. In the
implementation presented, we used a basic Monte Carlo splitting and termination
method called the comb, incorporated the weight cancellation method of Arnow
{\it et al.}, and exploited a new sampling method, the sewing method, that does
a large state space sampling as a succession of small state space samplings. We
illustrate the effectiveness of the algorithm by its determination of the two
largest eigenvalues of the transfer matrices for variously-sized
two-dimensional, zero field Ising models. While very likely useful for other
transfer matrix problems, the algorithm is however quite general and should
find application to a larger variety of problems requiring a few dominant
eigenvalues of a matrix.Comment: 22 pages, no figure
Local structure and site occupancy of Cd and Hg substitutions in CeTIn5 (T=Co, Rh, Ir)
The CeTIn5 superconductors (T=Co, Rh, or Ir) have generated great interest
due to their relatively Tc's, NFL behavior, and their proximity to AF order and
quantum critical points. In contrast to small changes with the T-species,
electron doping in CeT(In{1-x}Mx)5 with M=Sn and hole doping with Cd or Hg have
a dramatic effect on the electronic properties at very low concentrations. The
present work reports EXAFS measurements that address the substituent atom
distribution as a function of T, M, and x, near the superconducting phase.
Together with previous measurements for M=Sn, the proportion of the M atom
residing on the In(1) site, f{In(1)}, increases in the order M=Cd, Sn, and Hg,
ranging from about 40% to 70%, showing a strong preference for these
substituents to occupy the In(1) site (random=20%). In addition, f{In(1)}
ranges from 70% to 100% for M=Hg in the order T=Co, Rh, and Ir. These fractions
track the changes in the atomic radii of the various species, and help explain
the sharp dependence of Tc on substituting into the In site. However, it is
difficult to reconcile the small concentrations of M with the dramatic changes
in the ground state in the hole-doped materials with only an impurity
scattering model. These results therefore indicate that while such
substitutions have interesting local atomic structures with important
electronic and magnetic consequences, other local changes in the electronic and
magnetic structure are equally important in determining the bulk properties of
these materials.Comment: 10 pages, 7 figures, to appear in PR
Does access to a demand-led evidence briefing service improve uptake and use of research evidence by health service commissioners? A controlled before and after study
Background: The Health and Social Care Act mandated research use as a core consideration of health service commissioning arrangements in England. We undertook a controlled before and after study to evaluate whether access to a demand-led evidence briefing service improved the use of research evidence by commissioners compared with less intensive and less targeted alternatives. Methods: Nine Clinical Commissioning Groups (CCGs) in the North of England received one of three interventions: (A) access to an evidence briefing service; (B) contact plus an unsolicited push of non-tailored evidence; or (C) unsolicited push of non-tailored evidence. Data for the primary outcome measure were collected at baseline and 12 months using a survey instrument devised to assess an organisationsâ ability to acquire, assess, adapt and apply research evidence to support decision-making. Documentary and observational evidence of the use of the outputs of the service were sought. Results: Over the course of the study, the service addressed 24 topics raised by participating CCGs. At 12 months, the evidence briefing service was not associated with increases in CCG capacity to acquire, assess, adapt and apply research evidence to support decision-making, individual intentions to use research findings or perceptions of CCG relationships with researchers. Regardless of intervention received, participating CCGs indicated that they remained inconsistent in their research-seeking behaviours and in their capacity to acquire research. The inform al nature of decision-making processes meant that there was little traceability of the use of evidence. Low baseline and follow-up response rates and missing data limit the reliability of the findings. Conclusions: Access to a demand-led evidence briefing service did not improve the uptake and use of research evidence by NHS commissioners compare d with less intensive and less targeted alternatives. Commissioners appear well intentioned but ad hoc users of research. Further research is required on the effects of interventions and strategies to build individual and organisational capacity to use research
Slow crossover in YbXCu4 intermediate valence compounds
We compare the results of measurements of the magnetic susceptibility Chi(T),
the linear coefficient of specific heat Gamma(T)=C(T)/T and 4f occupation
number nf(T) for the intermediate valence compounds YbXCu4 (X = Ag, Cd, In, Mg,
Tl, Zn) to the predictions of the Anderson impurity model, calculated in the
non-crossing approximation (NCA). The crossover from the low temperature Fermi
liquid state to the high temperature local moment state is substantially slower
in the compounds than predicted by the NCA; this corresponds to the
''protracted screening'' recently predicted for the Anderson Lattice. We
present results for the dynamic susceptibility, measured through neutron
scattering experiments, to show that the deviations between theory and
experiment are not due to crystal field effects, and we present
x-ray-absorption fine-structure (XAFS) results that show the local crystal
structure around the X atoms is well ordered, so that the deviations probably
do not arise from Kondo Disorder. The deviations may correlate with the
background conduction electron density, as predicted for protracted screening.Comment: Submitted to Physical Review B on June 7, 2000, accepted for
publication November 2, 2000. Changes to the original manuscript include: 1)
a discussion of the relation of the slow crossover to the conduction electron
density; 2) a discussion of the relation of the reported results to earlier
photoemission results; and, 3) minor editorial change
An unquenched lattice QCD calculation of the mass of the bottom quark
We compute the b quark mass from dynamical lattice QCD with clover quarks.
The calculation is done at a fixed lattice spacing with sea quark masses as low
as half the strange quark mass. Our final result is m_b(m_b} = 4.25(2)(11) GeV,
where the first error is statistical and the last error is the systematic
uncertainty.Comment: 10 page
Crystal fields, disorder, and antiferromagnetic short-range order in Yb0.24Sn0.76Ru
We report extensive measurements on a new compound (Yb0.24Sn0.76)Ru that
crystallizes in the cubic CsCl structure. Valence band photoemission and L3
x-ray absorption show no divalent component in the 4f configuration of Yb.
Inelastic neutron scattering (INS) indicates that the eight-fold degenerate
J-multiplet of Yb3+ is split by the crystalline electric field (CEF) into a
{\Gamma}7 doublet ground state and a {\Gamma}8 quartet at an excitation energy
20 meV. The magnetic susceptibility can be fit very well by this CEF scheme
under the assumption that a {\Gamma}6 excited state resides at 32 meV; however,
the {\Gamma}8/{\Gamma}6 transition expected at 12 meV was not observed in the
INS. The resistivity follows a Bloch- Gr\"uneisen law shunted by a parallel
resistor, as is typical of systems subject to phonon scattering with no
apparent magnetic scattering. All of these properties can be understood as
representing simple local moment behavior of the trivalent Yb ion. At 1 K,
there is a peak in specific heat that is too broad to represent a magnetic
phase transition, consistent with absence of magnetic reflections in neutron
diffraction. On the other hand, this peak also is too narrow to represent the
Kondo effect in the {\Gamma}7 ground state doublet. On the basis of the
field-dependence of the specific heat, we argue that antiferromagnetic
shortrange order (possibly co-existing with Kondo physics) occurs at low
temperatures. The long-range magnetic order is suppressed because the Yb site
occupancy is below the percolation threshold for this disordered compound
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