169 research outputs found
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Strengthening the global system of protected areas post-2020: A perspective from the IUCN World Commission on Protected Areas
Protected areas are the cornerstones of biodiversity conservation and have never been more relevant than at the present time when the world is facing both a biodiversity and a climate change crisis. The International Union for Conservation of Nature (IUCN) World Commission on Protected Areas (WCPA) has been helping to set global standards and best practice guidelines in protected area planning and management for 60 years. Following this guidance, many countries have made significant progress toward their Aichi Target 11 commitments under the Convention on Biological Diversity (CBD). The global community will be coming together at the 15th Conference of the Parties of the CBD to set new biodiversity conservation targets for the next decade, as milestones to 2050 and a vision of “a world living in harmony with nature.” This paper lays out the WCPA perspective on priorities for supporting effective protected and conserved areas for the post-2020 era
Arctic Biodiversity Congress: Co-Chairs report, December 2-4, 2014
The Arctic Biodiversity Congress was the largest gathering of people in the history of the Arctic Council. It brought together 450 Arctic scientists, policy-makers, government officials, indigenous peoples, students and industry and civil society representatives to discuss the challenges facing Arctic biodiversity and the most appropriate actions for conservation and sustainable use of the Arctic’s living resources.
The Congress highlighted the work of the Conservation of Arctic Flora and Fauna (CAFF) working group and the Arctic Council in circumpolar biodiversity conservation and sustainable use, provided an opportunity to discuss the findings of the Arctic Biodiversity Assessment, 2013, and served as a forum for mainstreaming biodiversity - for ensuring that the 17 recommendations arising from the Arctic Biodiversity Assessment are implemented by not just governments, but by many organizations and people, and across sectors. During the Congress participants had opportunities to advise CAFF on the development of “Actions for Arctic Biodiversity: Implementation of the Arctic Biodiversity Assessment "Recommendations 2013-2021”
Posttraumatic Stress Disorder Symptoms Contribute to Staff Perceived Irritability, Anger, and Aggression After TBI in a Longitudinal Veteran Cohort: A VA TBI Model Systems Study
Objective
To examine the relationship between staff perceived irritability, anger, and aggression and posttraumatic stress disorder (PTSD) in veterans with traumatic brain injury (TBI) of all severity levels.
Design
Longitudinal cohort design.
Setting
Veterans Affairs Polytrauma Transitional Rehabilitation Programs.
Participants
Veterans and service members with TBI of all severity levels enrolled in the Veterans Affairs Polytrauma Rehabilitation Centers’ Traumatic Brain Injury Model System national database (N=240).
Interventions
Not applicable.
Main Outcome Measure
Univariable and multivariable logistic regression modeling was used to examine the association between irritability, anger, and aggression and potential risk factors, including PTSD symptoms. Irritability, anger, and aggression was measured as a single construct using an item from the Mayo-Portland Adaptability Inventory-4 that was rated by program staff at admission and discharge from the inpatient rehabilitation program. PTSD symptoms were assessed using the PTSD Checklist–Civilian Version.
Results
PTSD symptoms uniquely predicted program staff-rated irritability, anger, and aggression at discharge even after controlling for severity of TBI, age, male sex, education, and annual earnings. The model explained 19% of the variance in irritability, anger, and aggression.
Conclusions
When TBI severity and PTSD symptoms were considered simultaneously in a sample of veterans, only PTSD symptoms predicted staff-rated irritability, anger, and aggression. Given the negative outcomes linked with irritability, anger, and aggression, veterans may benefit from assessment and treatment of PTSD symptoms within rehabilitation settings
A theoretical framework for combining techniques that probe the link between galaxies and dark matter
We develop a theoretical framework that combines measurements of
galaxy-galaxy lensing, galaxy clustering, and the galaxy stellar mass function
in a self-consistent manner. While considerable effort has been invested in
exploring each of these probes individually, attempts to combine them are still
in their infancy despite the potential of such combinations to elucidate the
galaxy-dark matter connection, to constrain cosmological parameters, and to
test the nature of gravity. In this paper, we focus on a theoretical model that
describes the galaxy-dark matter connection based on standard halo occupation
distribution techniques. Several key modifications enable us to extract
additional parameters that determine the stellar-to-halo mass relation and to
simultaneously fit data from multiple probes while allowing for independent
binning schemes for each probe. In a companion paper, we demonstrate that the
model presented here provides an excellent fit to galaxy-galaxy lensing, galaxy
clustering, and stellar mass functions measured in the COSMOS survey from z=0.2
to z=1.0. We construct mock catalogs from numerical simulations to investigate
the effects of sample variance and covariance on each of the three probes.
Finally, we analyze and discuss how trends in each of the three observables
impact the derived parameters of the model. In particular, we investigate the
various features of the observed galaxy stellar mass function (low-mass slope,
plateau, knee, and high-mass cut-off) and show how each feature is related to
the underlying relationship between stellar and halo mass. We demonstrate that
the observed plateau feature in the stellar mass function at Mstellar~2x10^10
Msun is due to the transition that occurs in the stellar-to-halo mass relation
at Mhalo ~ 10^12 Msun from a low-mass power-law regime to a sub-exponential
function at higher stellar mass.Comment: 21 pages. Accepted to Ap
Galaxy-galaxy Lensing: Dissipationless Simulations Versus the Halo Model
Galaxy-galaxy lensing is a powerful probe of the relation between galaxies
and dark matter halos, but its theoretical interpretation requires a careful
modeling of various contributions, such as the contribution from central and
satellite galaxies. For this purpose, a phenomenological approach based on the
halo model has been developed, allowing for fast exploration of the parameter
space of models. In this paper, we investigate the ability of the halo model to
extract information from the g-g weak lensing signal by comparing it to
high-resolution dissipationless simulations that resolve subhalos. We find that
the halo model reliably determines parameters such as the host halo mass of
central galaxies, the fraction of galaxies that are satellites, and their
radial distribution inside larger halos. If there is a significant scatter
present in the central galaxy host halo mass distribution, then the mean and
median mass of that distribution can differ significantly from one another, and
the halo model mass determination lies between the two. This result suggests
that when analyzing the data, galaxy subsamples with a narrow central galaxy
halo mass distribution, such as those based on stellar mass, should be chosen
for a simpler interpretation of the results.Comment: 13 pages, 6 figures; minor changes made, matches MNRAS accepted
versio
Precision Measurements of the Cluster Red Sequence using an Error Corrected Gaussian Mixture Model
The red sequence is an important feature of galaxy clusters and plays a
crucial role in optical cluster detection. Measurement of the slope and scatter
of the red sequence are affected both by selection of red sequence galaxies and
measurement errors. In this paper, we describe a new error corrected Gaussian
Mixture Model for red sequence galaxy identification. Using this technique, we
can remove the effects of measurement error and extract unbiased information
about the intrinsic properties of the red sequence. We use this method to
select red sequence galaxies in each of the 13,823 clusters in the maxBCG
catalog, and measure the red sequence ridgeline location and scatter of each.
These measurements provide precise constraints on the variation of the average
red galaxy populations in the observed frame with redshift. We find that the
scatter of the red sequence ridgeline increases mildly with redshift, and that
the slope decreases with redshift. We also observe that the slope does not
strongly depend on cluster richness. Using similar methods, we show that this
behavior is mirrored in a spectroscopic sample of field galaxies, further
emphasizing that ridgeline properties are independent of environment.Comment: 33 pages, 14 Figures; A typo in Eq.A11 is fixed. The C++/Python codes
for ECGMM can be downloaded from:
https://sites.google.com/site/jiangangecgmm
The Galaxy Content of SDSS Clusters and Groups
Imaging data from the Sloan Digital Sky Survey are used to characterize the
population of galaxies in groups and clusters detected with the MaxBCG
algorithm. We investigate the dependence of Brightest Cluster Galaxy (BCG)
luminosity, and the distributions of satellite galaxy luminosity and satellite
color, on cluster properties over the redshift range 0.1 < z < 0.3. The size of
the dataset allows us to make measurements in many bins of cluster richness,
radius and redshift. We find that, within r_200 of clusters with mass above
3e13 h-1 M_sun, the luminosity function of both red and blue satellites is only
weakly dependent on richness. We further find that the shape of the satellite
luminosity function does not depend on cluster-centric distance for magnitudes
brighter than ^{0.25}M_i - 5log(h) < -19. However, the mix of faint red and
blue galaxies changes dramatically. The satellite red fraction is dependent on
cluster-centric distance, galaxy luminosity and cluster mass, and also
increases by ~5% between redshifts 0.28 and 0.2, independent of richness. We
find that BCG luminosity is tightly correlated with cluster richness, scaling
as L_{BCG} ~ M_{200}^{0.3}, and has a Gaussian distribution at fixed richness,
with sigma_{log L} ~ 0.17 for massive clusters. The ratios of BCG luminosity to
total cluster luminosity and characteristic satellite luminosity scale strongly
with cluster richness: in richer systems, BCGs contribute a smaller fraction of
the total light, but are brighter compared to typical satellites. This study
demonstrates the power of cross-correlation techniques for measuring galaxy
populations in purely photometric data.Comment: 22 pages, 14 figures, submitted to Ap
Late Pleistocene and Early Holocene Sea-Level History and Glacial Retreat Interpreted from Shell-Bearing Marine Deposits of Southeastern Alaska, USA
We leverage a data set of \u3e720 shell-bearing marine deposits throughout southeastern Alaska (USA) to develop updated relative sea-level curves that span the past ~14,000 yr. This data set includes site location, elevation, description when avail-able, and 436 14C ages, 45 of which are published here for the first time. Our sea-level curves suggest a peripheral forebulge developed west of the retreating Cordilleran Ice Sheet (CIS) margin between ca. 17,000 and 10,800 calibrated yr B.P. By 14,870 ± 630 to 12,820 ± 340 cal. yr B.P., CIS mar-gins had retreated from all of southeastern Alaska’s fjords, channels, and passages. At this time, isolated or stranded ice caps existed on the islands, with alpine or tidewater glaciers in many valleys. Paleoshorelines up to 25 m above sea level mark the maximum elevation of transgression in the southern portion of the study region, which was achieved by 11,000 ± 390 to 10,500 ± 420 cal. yr B.P. The presence of Pacific sardine (Sardinops sagax) and the abundance of charcoal in sediments that date between 11,000 ± 390 and 7630 ± 90 cal. yr B.P. suggest that both ocean and air temperatures in southeastern Alaska were relatively warm in the early Holocene. The sea-level and paleoenvironmental reconstruction presented here can inform future investigations into the glacial, volcanic, and archaeological history of southeastern Alaska
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