407 research outputs found
Testosterone and behavior in female marmosets
This study examines the role of testosterone in mediating behavior in common marmosets (Callithrix jacchus) and across the primate order. Testosterone has been primarily studied in males. Male behaviors related to mating success (competition and finding mates) are positively associated with testosterone levels in many bird and mammalian species. Conversely, male testosterone is negatively associated with infant care. The relationship between mating effort and infant care may represent a trade-off with testosterone serving as one hormonal mediator of these behaviors. Because females also exhibit mating competition and must balance mating investment with caring for offspring, I explored whether testosterone varied with female behavior in similar patterns as seen in males. I used a captive colony of common marmosets, at the Southwest National Primate Research Center in San Antonio, TX. To control for social context, I examined the relationship between testosterone and behavior during staged intruder tests and without any social manipulation. I compared female and male behavior and testosterone concentrations using non-invasively collected fecal samples. Neither female nor male testosterone showed a statistically significant increase in response to intruders, but female testosterone concentrations were indistinguishable from those of males during intruder tests. To test whether investing in mating behavior represented a trade-off with infant care in captive common marmosets, I also compared general behavior patterns between sexes. Females and males engaged in similar amounts of time spent being aggressive, engaging in sexual behavior, and caring for offspring. However, male common marmosets exhibited a correlation between aggression and distance from infants, whereas females did not. This suggests that the trade-off between mating effort and infant care exists for males but not females in common marmosets. I also compared testosterone concentrations without social manipulation between females and males and found no difference in fecal testosterone concentrations. A comparison of the ratio of male-to-female testosterone was done across primates. Mean male:female testosterone concentrations correlated with mating system across primates. However, the comparative data set was small and more data are needed to fully explore the relationship of testosterone and behavior in primates. The idea that testosterone may mediate behavior in females has implications in the evolution of mating and parental behavior
The VANDELS survey: Dust attenuation in star-forming galaxies at
We present the results of a new study of dust attenuation at redshifts based on a sample of star-forming galaxies from the VANDELS
spectroscopic survey. Motivated by results from the First Billion Years (FiBY)
simulation project, we argue that the intrinsic spectral energy distributions
(SEDs) of star-forming galaxies at these redshifts have a self-similar shape
across the mass range log probed by
our sample. Using FiBY data, we construct a set of intrinsic SED templates
which incorporate both detailed star formation and chemical abundance
histories, and a variety of stellar population synthesis (SPS) model
assumptions. With this set of intrinsic SEDs, we present a novel approach for
directly recovering the shape and normalization of the dust attenuation curve.
We find, across all of the intrinsic templates considered, that the average
attenuation curve for star-forming galaxies at is similar in shape
to the commonly-adopted Calzetti starburst law, with an average
total-to-selective attenuation ratio of . We show that the
optical attenuation () versus stellar mass () relation
predicted using our method is consistent with recent ALMA observations of
galaxies at in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field}
(HUDF), as well as empirical relations predicted by a
Calzetti-like law. Our results, combined with other literature data, suggest
that the relation does not evolve over the redshift range
, at least for galaxies with log.
Finally, we present tentative evidence which suggests that the attenuation
curve may become steeper at log.Comment: 16 pages, 12 figures, accepted for publication in MNRA
The VANDELS survey: Dust attenuation in star-forming galaxies at
We present the results of a new study of dust attenuation at redshifts based on a sample of star-forming galaxies from the VANDELS
spectroscopic survey. Motivated by results from the First Billion Years (FiBY)
simulation project, we argue that the intrinsic spectral energy distributions
(SEDs) of star-forming galaxies at these redshifts have a self-similar shape
across the mass range log probed by
our sample. Using FiBY data, we construct a set of intrinsic SED templates
which incorporate both detailed star formation and chemical abundance
histories, and a variety of stellar population synthesis (SPS) model
assumptions. With this set of intrinsic SEDs, we present a novel approach for
directly recovering the shape and normalization of the dust attenuation curve.
We find, across all of the intrinsic templates considered, that the average
attenuation curve for star-forming galaxies at is similar in shape
to the commonly-adopted Calzetti starburst law, with an average
total-to-selective attenuation ratio of . We show that the
optical attenuation () versus stellar mass () relation
predicted using our method is consistent with recent ALMA observations of
galaxies at in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field}
(HUDF), as well as empirical relations predicted by a
Calzetti-like law. Our results, combined with other literature data, suggest
that the relation does not evolve over the redshift range
, at least for galaxies with log.
Finally, we present tentative evidence which suggests that the attenuation
curve may become steeper at log.Comment: 16 pages, 12 figures, accepted for publication in MNRA
Trauma-informed Dialectical Behavior Therapy for Dissociative Identity Disorder
Dissociative symptoms are regarded as forms of disconnection from external stimuli, internal experiences, and interpersonal relationships. The Contextual Trauma Treatment (CTT) model for survivors of prolonged childhood abuse integrates Dialectical Behavior Therapy (DBT) treatment. DBT enhances capacities for skillful interactions with others, and identifying and tolerating emotional experiences through the use of didactically-taught skill-based groups that balance encouraging acceptance of difficulties with the recognition of the need for change. This presentation will provide an overview of CTT for conceptualizing dissociation in the context of family of origin environment and development, and describe how TRIP integrates trauma-informed and DBT-informed treatment
Conjunctival and Lingual Mucosal Neuromas Without Multiple Endocrine Neoplasia Type 2B
Purpose: To report a patient with conjunctival and buccal neuromas and enlarged corneal nerves without Multiple Endocrine Neoplasia 2B (MEN2B).
Observations: A 28-year-old female presented with progressively enlarging bilateral limbal conjunctival growths. Slit lamp examination was notable for enlarged corneal nerves and well-circumscribed gelatinous subepithelial limbal nodules. Systemic examination revealed similar lesions on the tongue. Conjunctival biopsy demonstrated a mucosal neuroma. The patient underwent endocrine workup for MEN2B and genetic testing for the RET-proto oncogene mutations, all of which were negative.
Conclusions and Importance: The findings in our patient may be compatible with pure mucosal neuroma syndrome. The pattern of conjunctival neuromas and enlarged corneal nerves should raise concern for MEN2B, a hereditary tumor predisposition syndrome with almost 100% incidence of medullary thyroid cancer, unless prophylactic thyroidectomy is performed. Accurate diagnosis and prompt referral for endocrine and genetic testing is critical. Isolated mucosal neuromas without endocrine manifestations of MEN2B can rarely occur in a “pure mucosal neuroma syndrome,” which is a diagnosis of exclusion in a setting of a negative workup
Constraining Lyman-alpha spatial offsets at from VANDELS slit spectroscopy
We constrain the distribution of spatially offset Lyman-alpha emission
(Ly) relative to rest-frame ultraviolet emission in high
redshift () Lyman-break galaxies (LBGs) exhibiting Ly emission
from VANDELS, a VLT/VIMOS slit-spectroscopic survey of the CANDELS Ultra Deep
Survey and Chandra Deep Field South fields (
total). Because slit spectroscopy compresses two-dimensional spatial
information into one spatial dimension, we use Bayesian inference to recover
the underlying Ly spatial offset distribution. We model the
distribution using a 2D circular Gaussian, defined by a single parameter
, the standard deviation expressed in polar
coordinates. Over the entire redshift range of our sample (), we find
kpc ( conf.),
corresponding to arcsec at . We also find that
decreases significantly with redshift. Because
Ly spatial offsets can cause slit-losses, the decrease in
with redshift can partially explain the increase
in the fraction of Ly emitters observed in the literature over this
same interval, although uncertainties are still too large to reach a strong
conclusion. If continues to decrease into the
reionization epoch, then the decrease in Ly transmission from galaxies
observed during this epoch might require an even higher neutral hydrogen
fraction than what is currently inferred. Conversely, if spatial offsets
increase with the increasing opacity of the IGM, slit losses may explain some
of the drop in Ly transmission observed at . Spatially resolved
observations of Ly and UV continuum at are needed to settle the
issue.Comment: Submitted to MNRA
The VANDELS survey: A strong correlation between Ly equivalent width and stellar metallicity at
We present the results of a new study investigating the relationship between
observed Ly equivalent width ((Ly)) and the
metallicity of the ionizing stellar population () for a sample of
star-forming galaxies at drawn from the VANDELS survey.
Dividing our sample into quartiles of rest-frame (Ly)
across the range -58 \unicode{xC5} \lesssim (Ly)
\lesssim 110 \unicode{xC5} we determine from full spectral
fitting of composite far-ultraviolet (FUV) spectra and find a clear
anti-correlation between (Ly) and . Our results
indicate that decreases by a factor between the lowest
(Ly) quartile
((Ly)\rangle=-18\unicode{xC5}) and the highest
(Ly) quartile
((Ly)\rangle=24\unicode{xC5}). Similarly,
galaxies typically defined as Lyman Alpha Emitters (LAEs;
(Ly) >20\unicode{xC5}) are, on average, metal poor with
respect to the non-LAE galaxy population ((Ly)
\leq20\unicode{xC5}) with
. Finally, based on the best-fitting stellar models, we
estimate that the increasing strength of the stellar ionizing spectrum towards
lower is responsible for of the observed variation
in (Ly) across our sample, with the remaining contribution
() being due to a decrease in the HI/dust covering fractions in
low galaxies.Comment: 10 pages, 6 figures, MNRAS accepte
Discovery of a rich proto-cluster at z=2.9 and associated diffuse cold gas in the VIMOS Ultra-Deep Survey (VUDS)
[Abridged] We characterise a massive proto-cluster at z=2.895 that we found
in the COSMOS field using the spectroscopic sample of the VIMOS Ultra-Deep
Survey (VUDS). This is one of the rare structures at z~3 not identified around
AGNs or radio galaxies, so it is an ideal laboratory to study galaxy formation
in dense environments. The structure comprises 12 galaxies with secure
spectroscopic redshift in an area of 7'x8', in a z bin of Dz=0.016. The
measured galaxy number overdensity is delta_g=12+/-2. This overdensity has
total mass of M~8.1x10^(14)M_sun in a volume of 13x15x17 Mpc^3. Simulations
indicate that such an overdensity at z~2.9 is a proto-cluster that will
collapse in a cluster of total mass M~2.5x10^(15)M_sun at z=0. We compare the
properties of the galaxies within the overdensity with a control sample at the
same z but outside the overdensity. We did not find any statistically
significant difference between the properties (stellar mass, SFR, sSFR, NUV-r,
r-K) of the galaxies inside and outside the overdensity. The stacked spectrum
of galaxies in the overdensity background shows a significant absorption
feature at the wavelength of Lya redshifted at z=2.895 (lambda=4736 A), with a
rest frame EW = 4+/- 1.4 A. Stacking only background galaxies without
intervening sources at z~2.9 along their line of sight, we find that this
absorption feature has a rest frame EW of 10.8+/-3.7 A, with a detection S/N of
~4. These EW values imply a high column density (N(HI)~3-20x10^(19)cm^(-2)),
consistent with a scenario where such absorption is due to intervening cold gas
streams, falling into the halo potential wells of the proto-cluster galaxies.
However, we cannot exclude the hypothesis that this absorption is due to the
diffuse gas within the overdensity.Comment: 15 pages, 9 figures, accepted for publication in A&A (revised version
after referee's comments and language editing
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