206 research outputs found
Serum levels of perfluorinated compounds and sperm Y:X chromosome ratio in two European populations and in Inuit from Greenland.
This study investigated whether perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), which exhibit reproductive toxicity in experimental animals, affect sperm sex chromosome ratio. The Y:X ratio was determined by fluorescence in situ hybridization. Serum concentrations of PFOA and PFOS were measured in 607 men from Greenland, Poland and Ukraine using liquid chromatography-tandem mass spectrometry. Data was analyzed by linear and nonlinear regression. We observed no associations between PFOA and Y:X ratio (p=0.845 in a linear model, p=0.296 in a nonlinear model). A positive nonlinear association between PFOS and Y:X ratio was observed (p=0.016), with no association in a linear model (p=0.118). Analyzing the populations separately, a negative trend between categorized PFOS exposure and Y:X ratio was observed for the Inuit (B=-0.002, p=0.044). In conclusion, there was a negative trend between Y:X ratio and PFOS in the Inuit, while there was no association between PFOA and the Y:X ratio in adult men
Discovery of Massive, Mostly Star-formation Quenched Galaxies with Extremely Large Lyman-alpha Equivalent Widths at z ~ 3
We report a discovery of 6 massive galaxies with both extremely large Lya
equivalent width and evolved stellar population at z ~ 3. These MAssive
Extremely STrong Lya emitting Objects (MAESTLOs) have been discovered in our
large-volume systematic survey for strong Lya emitters (LAEs) with twelve
optical intermediate-band data taken with Subaru/Suprime-Cam in the COSMOS
field. Based on the SED fitting analysis for these LAEs, it is found that these
MAESTLOs have (1) large rest-frame equivalent width of EW_0(Lya) ~ 100--300 A,
(2) M_star ~ 10^10.5--10^11.1 M_sun, and (3) relatively low specific star
formation rates of SFR/M_star ~ 0.03--1 Gyr^-1. Three of the 6 MAESTLOs have
extended Ly emission with a radius of several kpc although they show
very compact morphology in the HST/ACS images, which correspond to the
rest-frame UV continuum. Since the MAESTLOs do not show any evidence for AGNs,
the observed extended Lya emission is likely to be caused by star formation
process including the superwind activity. We suggest that this new class of
LAEs, MAESTLOs, provides a missing link from star-forming to passively evolving
galaxies at the peak era of the cosmic star-formation history.Comment: Accepted for publication in ApJ Letters on 15th July, 2015. 6 pages
including 3 figures and 2 table
Reflecting on loss in Papua New Guinea
This article takes up the conundrum of conducting anthropological fieldwork with people who claim that they have 'lost their culture,' as is the case with Suau people in the Massim region of Papua New Guinea. But rather than claiming culture loss as a process of dispossession, Suau claim it as a consequence of their own attempts to engage with colonial interests. Suau appear to have responded to missionization and their close proximity to the colonial-era capital by jettisoning many of the practices characteristic of Massim societies, now identified as 'kastom.' The rejection of kastom in order to facilitate their relations with Europeans during colonialism, followed by the mourning for kastom after independence, both invite consideration of a kind of reflexivity that requires action based on the presumed perspective of another
Pregnancy serum concentrations of perfluorinated alkyl substances and offspring behaviour and motor development at age 5-9 years--a prospective study
Background: In animal studies, perfluorinated alkyl substances affect growth and neuro-behavioural outcomes. Human epidemiological studies are sparse. The aim was to investigate the association between pregnancy serum concentrations of perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) and offspring behaviour and motor development at 5-9 years of age. Methods: Maternal sera from the INUENDO cohort (2002-2004) comprising 1,106 mother-child pairs from Greenland, Kharkiv (Ukraine) and Warsaw (Poland) were analysed for PFOS and PFOA, using liquid-chromatography-tandem-mass-spectrometry. Exposures were grouped into country specific as well as pooled tertiles as well as being used as continuous variables for statistical analyses. Child motor development and behaviour at follow-up (2010-2012) were measured by the Developmental Coordination Disorder Questionnaire 2007 (DCDQ) and Strength and Difficulties Questionnaire (SDQ), respectively. Exposure-outcome associations were analysed by multiple logistic and linear regression analyses. Results: In the pooled analysis, odds ratio (OR) (95% confidence interval (CI)) for hyperactivity was 3.1 (1.3, 7.2) comparing children prenatally exposed to the highest PFOA tertile with those exposed to the lowest PFOA tertile. Comparing children in the highest PFOS tertile with those in the lowest PFOS tertile showed elevated but statistically non-significant OR of hyperactivity (OR (95% CI) 1.7 (0.9, 3.2)). In Greenland, elevated PFOS was associated with higher SDQ-total scores indicating more behavioural problems (beta (95% CI) = 1.0 (0.1, 2.0)) and elevated PFOA was associated with higher hyperactivity sub-scale scores indicating more hyperactive behaviour (beta (95% CI) = 0.5 (0.1, 0.9)). Prenatal PFOS and PFOA exposures were not associated with motor difficulties. Conclusions: Prenatal exposure to PFOS and PFOA may have a small to moderate effect on children's neuro-behavioural development, specifically in terms of hyperactive behaviour. The associations were strongest in Greenland where exposure contrast is largest
Constraints on the Assembly and Dynamics of Galaxies: I. Detailed Rest-frame Optical Morphologies on Kiloparsec-scale of z ~ 2 Star-forming Galaxies
We present deep and high-resolution HST/NIC2 F160W imaging at 1.6micron of
six z~2 star-forming galaxies with existing near-IR integral field spectroscopy
from SINFONI at the VLT. The unique combination of rest-frame optical imaging
and nebular emission-line maps provides simultaneous insight into morphologies
and dynamical properties. The overall rest-frame optical emission of the
galaxies is characterized by shallow profiles in general (Sersic index n<1),
with median effective radii of ~5kpc. The morphologies are significantly clumpy
and irregular, which we quantify through a non-parametric morphological
approach, estimating the Gini (G), Multiplicity (Psi), and M_20 coefficients.
The strength of the rest-frame optical emission lines in the F160W bandpass
indicates that the observed structure is not dominated by the morphology of
line-emitting gas, and must reflect the underlying stellar mass distribution of
the galaxies. The sizes and structural parameters in the rest-frame optical
continuum and Halpha emission reveal no significant differences, suggesting
similar global distributions of the on-going star formation and more evolved
stellar population. While no strong correlations are observed between stellar
population parameters and morphology within the NIC2/SINFONI sample itself, a
consideration of the sample in the context of a broader range of z~2 galaxy
types indicates that these galaxies probe the high specific star formation rate
and low stellar mass surface density part of the massive z~2 galaxy population,
with correspondingly large effective radii, low Sersic indices, low G, and high
Psi and M_20. The combined NIC2 and SINFONI dataset yields insights of
unprecedented detail into the nature of mass accretion at high redshift.
[Abridged]Comment: 44 pages, 19 figures. Revised version accepted for publication in the
Astrophysical Journa
Constraints on the assembly and dynamics of galaxies. II. Properties of kiloparsec-scale clumps in rest-frame optical emission of z ~ 2 star-forming galaxies
We study the properties of luminous stellar clumps identified in deep, high
resolution HST/NIC2 F160W imaging at 1.6um of six z~2 star-forming galaxies
with existing near-IR integral field spectroscopy from SINFONI at the VLT.
Individual clumps contribute ~0.5%-15% of the galaxy-integrated rest-frame
~5000A emission, with median of about 2%; the total contribution of clump light
ranges from 10%-25%. The median intrinsic clump size and stellar mass are ~1kpc
and log(Mstar[Msun])~9, in the ranges for clumps identified in rest-UV or line
emission in other studies. The clump sizes and masses in the subset of disks
are broadly consistent with expectations for clump formation via gravitational
instabilities in gas-rich, turbulent disks given the host galaxies' global
properties. By combining the NIC2 data with ACS/F814W imaging available for one
source, and AO-assisted SINFONI Halpha data for another, we infer modest color,
M/L, and stellar age variations within each galaxy. In these two objects, sets
of clumps identified at different wavelengths do not fully overlap;
NIC2-identified clumps tend to be redder/older than ACS- or Halpha-identified
clumps without rest-frame optical counterparts. There is evidence for a
systematic trend of older ages at smaller galactocentric radii among the
clumps, consistent with scenarios where inward migration of clumps transports
material towards the central regions. From constraints on a bulge-like
component at radii <1-3kpc, none of the five disks in our sample appears to
contain a compact massive stellar core, and we do not discern a trend of bulge
stellar mass fraction with stellar age of the galaxy. Further observations are
necessary to probe the build-up of stellar bulges and the role of clumps in
this process.Comment: 29 pages, 11 figures. Revised version accepted for publication in the
Astrophysical Journa
Symptoms and quality of life in late stage Parkinson syndromes: a longitudinal community study of predictive factors
BACKGROUND
Palliative care is increasingly offered earlier in the cancer trajectory but rarely in Idiopathic Parkinson's Disease(IPD), Progressive Supranuclear Palsy(PSP) or Multiple System Atrophy(MSA). There is little longitudinal data of people with late stage disease to understand levels of need. We aimed to determine how symptoms and quality of life of these patients change over time; and what demographic and clinical factors predicted changes.
METHODS
We recruited 82 patients into a longitudinal study, consenting patients with a diagnosis of IPD, MSA or PSP, stages 3-5 Hoehn and Yahr(H&Y). At baseline and then on up to 3 occasions over one year, we collected self-reported demographic, clinical, symptom, palliative and quality of life data, using Parkinson's specific and generic validated scales, including the Palliative care Outcome Scale (POS). We tested for predictors using multivariable analysis, adjusting for confounders.
FINDINGS
Over two thirds of patients had severe disability, over one third being wheelchair-bound/bedridden. Symptoms were highly prevalent in all conditions - mean (SD) of 10.6(4.0) symptoms. More than 50% of the MSA and PSP patients died over the year. Over the year, half of the patients showed either an upward (worsening, 24/60) or fluctuant (8/60) trajectory for POS and symptoms. The strongest predictors of higher levels of symptoms at the end of follow-up were initial scores on POS (AOR 1.30; 95%CI:1.05-1.60) and being male (AOR 5.18; 95% CI 1.17 to 22.92), both were more predictive than initial H&Y scores.
INTERPRETATION
The findings point to profound and complex mix of non-motor and motor symptoms in patients with late stage IPD, MSA and PSP. Symptoms are not resolved and half of the patients deteriorate. Palliative problems are predictive of future symptoms, suggesting that an early palliative assessment might help screen for those in need of earlier intervention
Extreme damped Lyman- absorption in young star-forming galaxies at
The onset of galaxy formation is thought to be initiated by the infall of
neutral, pristine gas onto the first protogalactic halos. However, direct
constraints on the abundance of neutral atomic hydrogen (HI) in galaxies have
been difficult to obtain at early cosmic times. Here we present spectroscopic
observations with JWST of three galaxies at redshifts , about
Myr after the Big Bang, that show strong damped Lyman-
absorption ( cm) from HI in their local
surroundings, an order of magnitude in excess of the Lyman- absorption
caused by the neutral intergalactic medium at these redshifts. Consequently,
these early galaxies cannot be contributing significantly to reionization, at
least at their current evolutionary stages. Simulations of galaxy formation
show that such massive gas reservoirs surrounding young galaxies so early in
the history of the universe is a signature of galaxy formation in progress.Comment: Submitte
CANDELS Observations of the Structural Properties and Evolution of Galaxies in a Cluster at z=1.62
We discuss the structural and morphological properties of galaxies in a
z=1.62 proto-cluster using near-IR imaging data from Hubble Space Telescope
Wide Field Camera 3 data of the Cosmic Assembly Near-IR Deep Extragalactic
Legacy Survey (CANDELS). The cluster galaxies exhibit a clear color-morphology
relation: galaxies with colors of quiescent stellar populations generally have
morphologies consistent with spheroids, and galaxies with colors consistent
with ongoing star formation have disk-like and irregular morphologies. The size
distribution of the quiescent cluster galaxies shows a deficit of compact (<
1kpc), massive galaxies compared to CANDELS field galaxies at z=1.6. As a
result the cluster quiescent galaxies have larger average effective sizes
compared to field galaxies at fixed mass at greater than 90% significance.
Combined with data from the literature, the size evolution of quiescent cluster
galaxies is relatively slow from z~1.6 to the present, growing as
(1+z)^(-0.6+/-0.1). If this result is generalizable, then it implies that
physical processes associated with the denser cluster region seems to have
caused accelerated size growth in quiescent galaxies prior to z=1.6 and slower
subsequent growth at z<1.6 compared to galaxies in the lower density field. The
quiescent cluster galaxies at z=1.6 have higher ellipticities compared to lower
redshift samples at fixed mass, and their surface-brightness profiles suggest
that they contain extended stellar disks. We argue the cluster galaxies require
dissipationless (i.e., gas-poor or "dry") mergers to reorganize the disk
material and to match the relations for ellipticity, stellar mass, size, and
color of early-type galaxies in z<1 clusters.Comment: Accepted for publication in ApJ. 14 pages in emulateapj format.
Replacement includes improvements from referee report, and updates and
additions to reference
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