6,132 research outputs found
Emotional engagements predict and enhance social cognition in young chimpanzees
Social cognition in infancy is evident in coordinated triadic engagements, that is, infants attending jointly with social partners and objects. Current evolutionary theories of primate social cognition tend to highlight species differences in cognition based on human-unique cooperative motives. We consider a developmental model in which engagement experiences produce differential outcomes. We conducted a 10-year-long study in which two groups of laboratory-raised chimpanzee infants were given quantifiably different engagement experiences. Joint attention, cooperativeness, affect, and different levels of cognition were measured in 5- to 12-month-old chimpanzees, and compared to outcomes derived from a normative human database. We found that joint attention skills significantly improved across development for all infants, but by 12 months, the humans significantly surpassed the chimpanzees. We found that cooperativeness was stable in the humans, but by 12 months, the chimpanzee group given enriched engagement experiences significantly surpassed the humans. Past engagement experiences and concurrent affect were significant unique predictors of both joint attention and cooperativeness in 5- to 12-month-old chimpanzees. When engagement experiences and concurrent affect were statistically controlled, joint attention and cooperation were not associated. We explain differential social cognition outcomes in terms of the significant influences of previous engagement experiences and affect, in addition to cognition. Our study highlights developmental processes that underpin the emergence of social cognition in support of evolutionary continuity
Magnetic and electrical properties of (Pu,Lu)Pd3
We present measurements of the magnetic susceptibility, heat capacity and
electrical resistivity of PuLuPd, with =0, 0.1, 0.2, 0.5,
0.8 and 1. PuPd is an antiferromagnetic heavy fermion compound with
~K. With increasing Lu doping, both the Kondo and RKKY interaction
strengths fall, as judged by the Sommerfeld coefficient and N\'eel
temperature . Fits to a crystal field model of the resistivity also
support these conclusions. The paramagnetic effective moment
increases with Lu dilution, indicating a decrease in the
Kondo screening. In the highly dilute limit, approaches
the value predicted by intermediate coupling calculations. In conjunction with
an observed Schottky peak at 60~K in the magnetic heat capacity,
corresponding to a crystal field splitting of 12~meV, a mean-field
intermediate coupling model with nearest neighbour interactions has been
developed.Comment: 13 pages, 13 figure
Abundances of Baade's Window Giants from Keck/HIRES Spectra: I. Stellar Parameters and [Fe/H] Values
We present the first results of a new abundance survey of the Milky Way bulge
based on Keck/HIRES spectra of 27 K-giants in the Baade's Window (, ) field. The spectral data used in this study are of much higher resolution
and signal-to-noise than previous optical studies of Galactic bulge stars. The
[Fe/H] values of our stars, which range between -1.29 and , were used to
recalibrate large low resolution surveys of bulge stars. Our best value for the
mean [Fe/H] of the bulge is . This mean value is similar to the
mean metallicity of the local disk and indicates that there cannot be a strong
metallicity gradient inside the solar circle. The metallicity distribution of
stars confirms that the bulge does not suffer from the so-called ``G-dwarf''
problem. This paper also details the new abundance techniques necessary to
analyze very metal-rich K-giants, including a new Fe line list and regions of
low blanketing for continuum identification.Comment: Accepted for publication in January 2006 Astrophysical Journal. Long
tables 3--6 withheld to save space (electronic tables in journal paper). 53
pages, 10 figures, 9 table
Abundances in Stars from the Red Giant Branch Tip to the Near Main Sequence in M71: II. Iron Abundance
We present [Ffe/H] abundance results that involve a sample of stars with a
wide range in luminosity from luminous giants to stars near the turnoff in a
globular cluster. Our sample of 25 stars in M71 includes 10 giant stars more
luminous than the RHB, 3 horizontal branch stars, 9 giant stars less luminous
than the RHB, and 3 stars near the turnoff. We analyzed both Fe I and Fe II
lines in high dispersion spectra observed with HIRES at the W. M. Keck
Observatory. We find that the [Fe/H] abundances from both Fe I and Fe II lines
agree with each other and with earlier determinations. Also the [Fe/H] obtained
from Fe I and Fe II lines is constant within the rather small uncertainties for
this group of stars over the full range in Teff and luminosity, suggesting that
NLTE effects are negligible in our iron abundance determination. In this
globular cluster, there is no difference among the mean [Fe/H] of giant stars
located at or above the RHB, RHB stars, giant stars located below the RHB and
stars near the turnoff.Comment: Minor changes to conform to version accepted for publication, with
several new figures (Paper 2 of a pair
Modeling seismic wave propagation and amplification in 1D/2D/3D linear and nonlinear unbounded media
To analyze seismic wave propagation in geological structures, it is possible
to consider various numerical approaches: the finite difference method, the
spectral element method, the boundary element method, the finite element
method, the finite volume method, etc. All these methods have various
advantages and drawbacks. The amplification of seismic waves in surface soil
layers is mainly due to the velocity contrast between these layers and,
possibly, to topographic effects around crests and hills. The influence of the
geometry of alluvial basins on the amplification process is also know to be
large. Nevertheless, strong heterogeneities and complex geometries are not easy
to take into account with all numerical methods. 2D/3D models are needed in
many situations and the efficiency/accuracy of the numerical methods in such
cases is in question. Furthermore, the radiation conditions at infinity are not
easy to handle with finite differences or finite/spectral elements whereas it
is explicitely accounted in the Boundary Element Method. Various absorbing
layer methods (e.g. F-PML, M-PML) were recently proposed to attenuate the
spurious wave reflections especially in some difficult cases such as shallow
numerical models or grazing incidences. Finally, strong earthquakes involve
nonlinear effects in surficial soil layers. To model strong ground motion, it
is thus necessary to consider the nonlinear dynamic behaviour of soils and
simultaneously investigate seismic wave propagation in complex 2D/3D geological
structures! Recent advances in numerical formulations and constitutive models
in such complex situations are presented and discussed in this paper. A crucial
issue is the availability of the field/laboratory data to feed and validate
such models.Comment: of International Journal Geomechanics (2010) 1-1
HOPE: Help fOr People with money, employment, benefit or housing problems: study protocol for a randomised controlled trial
Background:
Self-harm and suicide increase in times of economic recession. Factors including job loss, austerity measures, financial difficulties and house repossession contribute to the risk. Vulnerable individuals commonly experience difficulties in navigating the benefits system and in accessing the available sources of welfare and debt advice, and this contributes to their distress. Our aim is to determine the feasibility and acceptability of a brief psychosocial intervention (the “HOPE” service) for people presenting to hospital emergency departments (ED) following self-harm or in acute distress because of financial, employment, or welfare (benefit) difficulties.
Method:
A pilot study including randomisation will be employed to determine whether it is possible to undertake a full-scale trial. Twenty people presenting to the ED who have self-harmed, have suicidal thoughts and depression and/or are in crisis and where financial, employment or benefit problems are cited as contributory factors will be asked to consent to random allocation to the intervention or control arm on a 2:1 basis. People who require secondary mental health follow-up will be excluded. Those randomised to the intervention arm will receive up to six sessions with a mental health worker who will provide practical help with financial and other problems. The mental health worker will use the motivational interviewing method in their interactions with participants. Control participants will receive one session signposting them to existing relevant support organisations. Participants will be followed up after 3 months. Participants and the mental health workers will take part in qualitative interviews to enable refinement of the intervention. The acceptability of outcome measures including the PHQ-9, GAD-7, repeat self-harm, EQ5D-5L and questions about debt, employment and welfare benefits will be explored.
Discussion:
This study will assess whether a full-scale randomised trial of this novel intervention to prevent self-harm among those distressed because of financial difficulties is feasible, including the acceptability of randomisation, potential rate of recruitment and the acceptability of outcome measures.
Trial registration:
ISRCTN5853124
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