3,866 research outputs found
Inclusive Fitness, Reciprocal Altruism and Emotion: Testing a Social-Functional Model of Anger and Gratitude Across Kin and Non-Kin Relationships
Guided by the theories of inclusive fitness (Hamilton, 1964) and reciprocal altruism (Trivers, 1971), two studies tested hypotheses related to the notion that emotions are part of an evolved psychological system that functions, in part, to regulate social exchange. Emotional experience and exchange behaviors were predicted to vary based on both the structure of the situation and the type of relationship one has with a partner. Due to an absence of inclusive fitness effects, interaction with non-kin (compared with kin) exchange partners was expected to trigger more intense emotional responses. Study 1 found that, as expected, unfair offers led to feelings of anger, but more so for non-kin partners compared to kin partners. Similarly, fair offers led to feelings of gratitude, but more so for non-kin partners. Study 2 used a 3 (emotion induction: anger, gratitude, control) by 4 (relationship partner: stranger, friend, cousin, sibling) by 2 (social dilemma task: take-some, give-some) experimental design and found evidence in support of the prediction that emotions are more likely to influence exchange behaviors with non-kin partners compared with kin partners. This research extends the social-functional approach to emotions into the context of evolutionary social psychological theory
An Overview of Two Incidents Involving African American Fraternities at Indiana University
The current campus climate facing African American Greek fraternal organizations at Indiana University (IU) can be examined through critical incidents of the past. A historical analysis of data sources associated with two incidents involving these organizations at IU provides a better understanding of the challenges students in these organizations may face. This paper aims to provide practitioners with an understanding of how specific policy changes for these fraternities may affect their members, as well as the student body they serve
Graviton Emission in the Bulk from a Higher-Dimensional Schwarzschild Black Hole
We consider the evaporation of (4+n)-dimensional non-rotating black holes
into gravitons. We calculate the energy emission rate for gravitons in the bulk
obtaining analytical solutions of the master equation satisfied by all three
types (S,V,T) of gravitational perturbations. Our results, valid in the
low-energy regime, show a vector radiation dominance for every value of n,
while the relative magnitude of the energy emission rate of the subdominant
scalar and tensor radiation depends on n. The low-energy emission rate in the
bulk for gravitons is well below that for a scalar field, due to the absence of
the dominant l=0,1 modes from the gravitational spectrum. Higher partial waves
though may modify this behaviour at higher energies. The calculated low-energy
emission rate, for all types of degrees of freedom decreases with n, although
the full energy emission rate, integrated over all frequencies, is expected to
increase with n, as in the previously studied case of a bulk scalar field.Comment: 17 pages, 2 figures, minor corrections, accepted by Phys. Lett.
Response to comment on "Human-specific gain of function in a developmental enhancer"
Duret and Galtier argue that human-specific sequence divergence and gain of function in the HACNS1 enhancer result from deleterious biased gene conversion (BGC) with no contribution from positive selection. We reinforce our previous conclusion by analyzing hypothesized BGC
events genomewide and assessing the effect of recombination rates on human-accelerated conserved noncoding sequence ascertainment. We also provide evidence that AT → GC substitution bias can coexist with positive selection
The White Dwarf Population in NGC 1039 (M34) and the White Dwarf Initial-Final Mass Relation
We present the first detailed photometric and spectroscopic study of the
white dwarfs (WDs) in the field of the ~225 Myr old (log tau_cl = 8.35) open
cluster NGC 1039 (M34) as part of the ongoing Lick-Arizona White Dwarf Survey.
Using wide-field UBV imaging, we photometrically select 44 WD candidates in
this field. We spectroscopically identify 19 of these objects as WDs; 17 are
hydrogen-atmosphere DA WDs, one is a helium-atmosphere DB WD, and one is a cool
DC WD that exhibits no detectable absorption lines. We find an effective
temperature (T_eff) and surface gravity (log g) for each DA WD by fitting
Balmer-line profiles from model atmospheres to the observed spectra. WD
evolutionary models are then invoked to derive masses and cooling times for
each DA WD. Of the 17 DAs, five are at the approximate distance modulus of the
cluster. Another WD with a distance modulus 0.45 mag brighter than that of the
cluster could be a double-degenerate binary cluster member, but is more likely
to be a field WD. We place the five single cluster member WDs in the empirical
initial-final mass relation and find that three of them lie very close to the
previously derived linear relation; two have WD masses significantly below the
relation. These outliers may have experienced some sort of enhanced mass loss
or binary evolution; however, it is quite possible that these WDs are simply
interlopers from the field WD population. Eight of the 17 DA WDs show
significant CaII K absorption; comparison of the absorption strength with the
WD distances suggests that the absorption is interstellar, though this cannot
be confirmed with the current data.Comment: 24 pages, 13 figures. Accepted for publication in the Astronomical
Journal. Figures 1, 2 and 3 reduced in resolutio
Non-monotonicity of the frictional bimaterial effect
Sliding along frictional interfaces separating dissimilar elastic materials
is qualitatively different from sliding along interfaces separating identical
materials due to the existence of an elastodynamic coupling between interfacial
slip and normal stress perturbations in the former case. This bimaterial
coupling has important implications for the dynamics of frictional interfaces,
including their stability and rupture propagation along them. We show that
while this bimaterial coupling is a monotonically increasing function of the
bimaterial contrast, when it is coupled to interfacial shear stress
perturbations through a friction law, various physical quantities exhibit a
non-monotonic dependence on the bimaterial contrast. In particular, we show
that for a regularized Coulomb friction, the maximal growth rate of unstable
interfacial perturbations of homogeneous sliding is a non-monotonic function of
the bimaterial contrast, and provide analytic insight into the origin of this
non-monotonicity. We further show that for velocity-strengthening
rate-and-state friction, the maximal growth rate of unstable interfacial
perturbations of homogeneous sliding is also a non-monotonic function of the
bimaterial contrast. Results from simulations of dynamic rupture along a
bimaterial interface with slip-weakening friction provide evidence that the
theoretically predicted non-monotonicity persists in non-steady, transient
frictional dynamics.Comment: 14 pages, 5 figure
Signatures of accretion events in the halos of early-type galaxies from comparing PNe and GCs kinematics
We have compared the halo kinematics traced by globular clusters (GCs) and
planetary nebulae (PNe) for two elliptical galaxies in the Fornax and Virgo
clusters NGC 1399 and NGC 4649, and for the merger remnant NGC 5128 (Centaurus
A). We find differences in the rotational properties of the PN, red GC, and
blue GC systems in all these three galaxies. NGC 1399 PNe and GCs show line of
sight velocity distributions in specific regions that are significantly
different, based on Kolmogorov-Smirnov tests. The PN system shows multi-spin
components, with nearly opposite direction of rotation in the inner and the
outer parts. The GCs velocity field is not point-symmetric in the outer regions
of the galaxy, indicating that the system has not reached dynamical equilibrium
yet. In NGC 4649 PNe, red and blue GCs have different rotation axes and
rotational velocities. Finally, in NGC 5128 both PNe and GCs deviate from
equilibrium in the outer regions of the galaxy, and in the inner regions the PN
system is rotationally supported, whereas the GC system is dominated by
velocity dispersion. The observed different kinematic properties, including
deviations from point-symmetry, between PNe and GCs suggest that these systems
are accreted at different times by the host galaxy, and the most recent
accretion took place only few Gyr ago.We discuss two scenarios which may
explain some of these differences: i) tidal stripping of loosely-bound GCs, and
ii) multiple accretion of low luminosity and dwarf galaxies. Because these two
mechanisms affect mostly the GC system, differences with the PNe kinematics can
be expected.Comment: 14 pages, 13 figures, Accepted for publication in MNRAS. This new
version contains an improved analysis, which includes the study of
point-symmetry in the velocity fields and its implications for dynamical
equilibriu
The Asymptotic Number of Attractors in the Random Map Model
The random map model is a deterministic dynamical system in a finite phase
space with n points. The map that establishes the dynamics of the system is
constructed by randomly choosing, for every point, another one as being its
image. We derive here explicit formulas for the statistical distribution of the
number of attractors in the system. As in related results, the number of
operations involved by our formulas increases exponentially with n; therefore,
they are not directly applicable to study the behavior of systems where n is
large. However, our formulas lend themselves to derive useful asymptotic
expressions, as we show.Comment: 16 pages, 1 figure. Minor changes. To be published in Journal of
Physics A: Mathematical and Genera
Effective equidistribution and the Sato-Tate law for families of elliptic curves
Extending recent work of others, we provide effective bounds on the family of
all elliptic curves and one-parameter families of elliptic curves modulo p (for
p prime tending to infinity) obeying the Sato-Tate Law. We present two methods
of proof. Both use the framework of Murty-Sinha; the first involves only
knowledge of the moments of the Fourier coefficients of the L-functions and
combinatorics, and saves a logarithm, while the second requires a Sato-Tate
law. Our purpose is to illustrate how the caliber of the result depends on the
error terms of the inputs and what combinatorics must be done.Comment: Version 1.1, 24 pages: corrected the interpretation of Birch's moment
calculations, added to the literature review of previous results
Galactic orbital motions in the Dark Matter, MOdified Newtonian Dynamics and MOdified Gravity scenarios
We simultaneously integrate in a numerical way the equations of motion of
both the Magellanic Clouds (MCs) in MOND, MOG and CDM for -1 <= t <= +1 Gyr to
see if, at least in principle, it is possible to discriminate between them
(Abridged version).Comment: LaTex2e, 11 pages, 2 tables, 8 figures. Issues concerning the masses
of MCs clarified. Integration time changed to -1 Gyr <= t <= +1 Gyr. To
appear in Monthly Notices of the Royal Astronomical Society (MNRAS
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