704 research outputs found
The impact of the mode of thought in complex decisions: intuitive decisions are better
A number of recent studies have reported that decision quality is enhanced under conditions of inattention or distraction (unconscious thought; Dijksterhuis, 2004; Dijksterhuis and Nordgren, 2006; Dijksterhuis et al., 2006). These reports have generated considerable controversy, for both experimental (problems of replication) and theoretical reasons (interpretation). Here we report the results of four experiments. The first experiment replicates the unconscious thought effect, under conditions that validate and control the subjective criterion of decision quality. The second and third experiments examine the impact of a mode of thought manipulation (without distraction) on decision quality in immediate decisions. Here we find that intuitive or affective manipulations improve decision quality compared to analytic/deliberation manipulations. The fourth experiment combines the two methods (distraction and mode of thought manipulations) and demonstrates enhanced decision quality, in a situation that attempts to preserve ecological validity. The results are interpreted within a framework that is based on two interacting subsystems of decision-making: an affective/intuition based system and an analytic/deliberation system
Double photo-ionization of He near a polarizable surface
We calculate the differential cross-section of the direct double
photo-ionization of He physisorbed on a polarizable surface. By including the
influence of the surface potential in the correlated two-electron final state
wavefunction, we show that the differential cross-section carries detailed
information on the electronic correlations at the surface. In particular,
photo-emission along opposite directions, which is prohibited in the free
space, is allowed if the surface potential is long-ranged.Comment: To appear in Phys. Rev. B - Rapid Comm. - 4 pages, 2 PostScript
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Explaining religious differentials in family-size preference: Evidence from Nepal in 1996
This paper presents an examination of how religio-ethnic identity, individual religiosity, and family membersâ religiosity are related to preferred family size in Nepal. Analyses of survey data from the Chitwan Valley Family Study show that socioeconomic characteristics and individual experiences can suppress, as well as largely account for, religio-ethnic differences in fertility preferences. These religio-ethnic differentials are associated with variance in particularized religious theologies or general value orientations (like son preference) across groups. In addition, individual and family religiosity are both positively associated with preferred family size, seemingly because of their association with religious beliefs that are likely to shape fertility strategies. These findings suggest improvements in how we conceptualize and empirically measure supra-individual religious influence in a variety of settings and for a range of demographically interesting outcomes
Unveiling the chemical fingerprint of phosphorus-rich stars I. In the infrared region of APOGEE-2
The origin of phosphorus, one of the essential elements for life on Earth, is
currently unknown. Prevalent models of Galactic chemical evolution (GCE)
underestimate the amount of P compared to observations. The recently discovered
P-rich ([P/Fe] > 1 dex) and metal-poor giants further challenge current
theories on stellar nucleosynthesis. Since the observed stars are low-mass
giants, our primary goal is to find clues on their progenitor. By increasing
the number of known P-rich stars, we aim to narrow down a reliable chemical
abundance pattern and to place robust constraints on the responsible
nucleosynthetic mechanism. In the long term, identifying the progenitor of the
P-rich stars may contribute to the search for the source of P in our Galaxy. We
performed a detailed chemical abundance analysis based on the H-band spectra
from APOGEE-2 (DR17). Employing the BACCHUS code, we measured the abundances of
13 elements in the sample, which is mainly composed of a recent collection of
Si-enhanced giants. We also analyzed the orbital motions and compared the
abundance results to possible nucleosynthetic formation scenarios, and also to
detailed GCE models. We enlarged the sample of confirmed P-rich stars from 16
to 78 giants, which represents the largest sample of P-rich stars to date.
Significant enhancements in O, Al, Si and Ce, as well as systematic
correlations among the elements, unveil the chemical fingerprint of the P-rich
stars. The high Mg and C+N found in some of the P-rich stars with respect to
P-normal stars is not confirmed over the full sample. Strikingly, the strong
over-abundance in the -element Si is accompanied by normal Ca and S
abundances. Our analysis of the orbital motion showed that the P-rich stars do
not belong to a specific sub-population. In addition, we confirm that the
majority of the sample stars are not part of binary systems.Comment: 29 pages, 18 figures, 8 tables, accepted for publication in Astronomy
& Astrophysic
Fermion family recurrences in the Dyson-Schwinger formalism
We study the multiple solutions of the truncated propagator Dyson-Schwinger
equation for a simple fermion theory with Yukawa coupling to a scalar field.
Upon increasing the coupling constant , other parameters being fixed, more
than one non-perturbative solution breaking chiral symmetry becomes possible
and we find these numerically. These ``recurrences'' appear as a mechanism to
generate different fermion generations as quanta of the same fundamental field
in an interacting field theory, without assuming any composite structure. The
number of recurrences or flavors is reduced to a question about the value of
the Yukawa coupling, and has no special profound significance in the Standard
Model. The resulting mass function can have one or more nodes and the
measurement that potentially detects them can be thought of as a collider-based
test of the virtual dispersion relation for the charged
lepton member of each family. This requires three independent measurements of
the charged lepton's energy, three-momentum and off-shellness. We illustrate
how this can be achieved for the (more difficult) case of the tau lepton
Complete Break Up of Ortho Positronium (Ps)- Hydrogenic ion System
The dynamics of the complete breakup process in an Ortho Ps - He+ system
including electron loss to the continuum (ELC) is studied where both the
projectile and the target get ionized. The process is essentially a four body
problem and the present model takes account of the two centre effect on the
electron ejected from the Ps atom which is crucial for a proper description of
the ELC phenomena. The calculations are performed in the framework of Coulomb
Distorted Eikonal Approximation. The exchange effect between the target and the
projectile electron is taken into account in a consistent manner. The proper
asymptotic 3-body boundary condition for this ionization process is also
satisfied in the present model. A distinct broad ELC peak is noted in the fully
differential cross sections (5DCS) for the Ps electron corroborating
qualitatively the experiment for the Ps - He system. Both the dynamics of the
ELC from the Ps and the ejected electron from the target He+ in the FDCS are
studied using coplanar geometry. Interesting features are noted in the FDCS for
both the electrons belonging to the target and the projectile.Comment: 14 pages,7 figure
A quasi classical approach to electron impact ionization
A quasi classical approximation to quantum mechanical scattering in the
Moeller formalism is developed. While keeping the numerical advantage of a
standard Classical--Trajectory--Monte--Carlo calculation, our approach is no
longer restricted to use stationary initial distributions. This allows one to
improve the results by using better suited initial phase space distributions
than the microcanonical one and to gain insight into the collision mechanism by
studying the influence of different initial distributions on the cross section.
A comprehensive account of results for single, double and triple differential
cross sections for atomic hydrogen will be given, in comparison with experiment
and other theories.Comment: 21 pages, 10 figures, submitted to J Phys
Three charged particles in the continuum. Astrophysical examples
We suggest a new adiabatic approach for description of three charged
particles in the continuum. This approach is based on the Coulomb-Fourier
transformation (CFT) of three body Hamiltonian, which allows to develop a
scheme, alternative to Born-Oppenheimer one.
The approach appears as an expansion of the kernels of corresponding integral
transformations in terms of small mass-ratio parameter. To be specific, the
results are presented for the system in the continuum. The wave function
of a such system is compared with that one which is used for estimation of the
rate for triple reaction which take place as a step of
-cycle in the center of the Sun. The problem of microscopic screening for
this particular reaction is discussed
Dental-derived stem cells and biowaste biomaterials: Whatâs next in bone regenerative medicine applications
The human teeth and oral cavity harbor various populations of mesenchymal stem cells (MSCs), so called dental-derived stem cells (D-dSCs) with self-renewing and multilineage differentiation capabilities. D-dSCs properties involves a strong paracrine component resulting from the high levels of bioactive molecules they secrete in response to the local microenvironment. Altogether, this viewpoint develops a general picture of current innovative strategies to employ D-dSCs combined with biomaterials and bioactive factors for regenerative medicine purposes, and offers information regarding the available scientific data and possible applications
Hyperspherical partial wave calculation for double photoionization of the helium atom at 20 eV excess energy
Hyperspherical partial wave approach has been applied here in the study of
double photoionization of the helium atom for equal energy sharing geometry at
20 eV excess energy. Calculations have been done both in length and velocity
gauges and are found to agree with each other, with the CCC results and with
experiments and exhibit some advantages of the corresponding three particle
wave function over other wave functions in use.Comment: 11 pages, 1 figure, submitted to J. Phys B: At. Mol. Opt. Phys; v2 -
revised considerably, rewritten using ioplatex clas
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