845 research outputs found
From Weak Lensing to non-Gaussianity via Minkowski Functionals
We present a new harmonic-domain approach for extracting morphological
information, in the form of Minkowski Functionals (MFs), from weak lensing (WL)
convergence maps. Using a perturbative expansion of the MFs, which is expected
to be valid for the range of angular scales probed by most current weak-lensing
surveys, we show that the study of three generalized skewness parameters is
equivalent to the study of the three MFs defined in two dimensions. We then
extend these skewness parameters to three associated skew-spectra which carry
more information about the convergence bispectrum than their one-point
counterparts. We discuss various issues such as noise and incomplete sky
coverage in the context of estimation of these skew-spectra from realistic
data. Our technique provides an alternative to the pixel-space approaches
typically used in the estimation of MFs, and it can be particularly useful in
the presence of masks with non-trivial topology. Analytical modeling of weak
lensing statistics relies on an accurate modeling of the statistics of
underlying density distribution. We apply three different formalisms to model
the underlying dark-matter bispectrum: the hierarchical ansatz, halo model and
a fitting function based on numerical simulations; MFs resulting from each of
these formalisms are computed and compared. We investigate the extent to witch
late-time gravity-induced non-Gaussianity (to which weak lensing is primarily
sensitive) can be separated from primordial non-Gaussianity and how this
separation depends on source redshift and angular scale.Comment: 22 Pages, 12 Figures. Submitting To MNRA
IL-10 inhibits transcription elongation of the human TNF gene in primary macrophages
IL-10 plays a central nonredundant role in limiting inflammation in vivo. However, the mechanisms involved remain to be resolved. Using primary human macrophages, we found that IL-10 inhibits selected inflammatory genes, primarily at a level of transcription. At the TNF gene, this occurs not through an inhibition of RNA polymerase II (Pol II) recruitment and transcription initiation but through a mechanism targeting the stimulation of transcription elongation by cyclin-dependent kinase (CDK) 9. We demonstrated an unanticipated requirement for a region downstream of the TNF 3′ untranslated region (UTR) that contains the nuclear factor κB (NF-κB) binding motif (κB4) both for induction of transcription by lipopolysaccharide (LPS) and its inhibition by IL-10. IL-10 not only inhibits the recruitment of RelA to regions containing κB sites at the TNF gene but also to those found at other LPS-induced genes. We show that although IL-10 elicits a general block in RelA recruitment to its genomic targets, the gene-specific nature of IL-10’s actions are defined through the differential recruitment of CDK9 and the control of transcription elongation. At TNF, but not NFKBIA, the consequence of RelA recruitment inhibition is a loss of CDK9 recruitment, preventing the stimulation of transcription elongation
Phylogenomics of the genus Tursiops and closely related Delphininae reveals extensive reticulation among lineages and provides inference about eco-evolutionary drivers
Phylogeographic inference has provided extensive insight into the relative roles of geographical isolation and ecological processes during evolutionary radiations. However, the importance of cross-lineage admixture in facilitating adaptive radiations is increasingly being recognised, and suggested as a main cause of phylogenetic uncertainty. In this study, we used a double digest RADseq protocol to provide a high resolution (∼ 4 Million bp) nuclear phylogeny of the Delphininae. Phylogenetic resolution of this group has been especially intractable, likely because it has experienced a recent species radiation. We carried out cross-lineage reticulation analyses, and tested for several sources of potential bias in determining phylogenies from genome sampling data. We assessed the divergence time and historical demography of T. truncatus and T. aduncus by sequencing the T. aduncus genome and comparing it with the T. truncatus reference genome. Our results suggest monophyly for the genus Tursiops, with the recently proposed T. australis species falling within the T. aduncus lineage. We also show the presence of extensive cross-lineage gene flow between pelagic and European coastal ecotypes of T. truncatus, as well as in the early stages of diversification between spotted (Stenella frontalis; Stenella attenuata), spinner (Stenella longirostris), striped (Stenella coeruleoalba), common (Delphinus delphis), and Fraser’s (Lagenodelphis hosei) dolphins. Our study suggests that cross-lineage gene flow in this group has been more extensive and complex than previously thought. In the context of biogeography and local habitat dependence, these results improve our understanding of the evolutionary processes determining the history of this lineage
Effect of a shelf-furnished screen on space utilisation and social behaviour of indoor group-housed cats (Felis silvestris catus)
The environment of the laboratory cat can be restrictive and may impact their welfare. Enrichment is often provided to alleviate welfare impacts but is seldom assessed or validated for efficacy. This study investigated the effect of novel room furniture (a screen) on the expression of agonistic and affiliative behaviours and space utilisation amongst colony-housed laboratory cats. Video footage of cats (N = 29) housed in social rooms (N = 4) was collected for 2 days before (baseline phase), 4 days during (test phase) and 2 days following (removal phase) introduction of the novel furniture. Space utilisation data were collected using scan sampling every 10 min and analysed using a generalised linear mixed effects model and Tukey’s HSD test. Behavioural data were collected using continuous sampling for 3 h a day in 6 × 30 min episodes and analysed using a Poisson generalised mixed effects model.
Significantly more agonistic events occurred before the morning feed compared to after feeding within all phases (pre-feed mean = 0.227; post-feed mean = 0.026; P < 0.0001). However no significant differences were observed before the morning feed compared to after feeding between phases indicating that the screen had no effect on reducing pre-feed aggression at the morning feed. Agonistic behaviours occurred significantly less following the morning feed during the test phase when compared to the baseline phase (test post-feed mean = 0.011; baseline post-feed mean = 0.029; P = 0.0342). Significant differences were also observed on removal of the screen with agonistic behaviour increasing above baseline at the afternoon pre-feed time point, possibly indicative of aggression due to frustration or a rebound effect (removal pre-feed mean = 0.151; baseline pre-feed mean 0.048; P < 0.0001). Affiliative interactions between phases were not significantly affected by screen presence. Given the ratio of the screen to existing shelving (0.58:0.42) a statistical significant proportion of cats were found to be on the screen in the test phase of the study (P < 0.0001). This study suggests that exploiting the unused vertical space by the addition of stand-alone shelving should be considered a valuable resource for the cat by increasing useable space and reducing agonistic interactions
A multi-targeted approach to suppress tumor-promoting inflammation
Cancers harbor significant genetic heterogeneity and patterns of relapse following many therapies are due to evolved resistance to treatment. While efforts have been made to combine targeted therapies, significant levels of toxicity have stymied efforts to effectively treat cancer with multi-drug combinations using currently approved therapeutics. We discuss the relationship between tumor-promoting inflammation and cancer as part of a larger effort to develop a broad-spectrum therapeutic approach aimed at a wide range of targets to address this heterogeneity. Specifically, macrophage migration inhibitory factor, cyclooxygenase-2, transcription factor nuclear factor-κB, tumor necrosis factor alpha, inducible nitric oxide synthase, protein kinase B, and CXC chemokines are reviewed as important antiinflammatory targets while curcumin, resveratrol, epigallocatechin gallate, genistein, lycopene, and anthocyanins are reviewed as low-cost, low toxicity means by which these targets might all be reached simultaneously. Future translational work will need to assess the resulting synergies of rationally designed antiinflammatory mixtures (employing low-toxicity constituents), and then combine this with similar approaches targeting the most important pathways across the range of cancer hallmark phenotypes
Detecting Sunyaev-Zel'dovich clusters with PLANCK: II. Foreground components and optimised filtering schemes
The PLANCK mission is the most sensitive all-sky CMB experiment currently
planned. The High Frequency Instrument (HFI) will be especially suited for
observing clusters of galaxies by their thermal Sunyaev-Zel'dovich (SZ) effect.
In order to assess PLANCKs SZ-capabilities in the presence of spurious signals,
a simulation is presented that combines maps of the thermal and kinetic
SZ-effects with a realisation of the cosmic microwave background (CMB), in
addition to Galactic foregrounds (synchrotron emission, free-free emission,
thermal emission from dust, CO-line radiation) as well as the sub-millimetric
emission from celestial bodies of our Solar system. Additionally, observational
issues such as the finite angular resolution and spatially non-uniform
instrumental noise of PLANCKs sky maps are taken into account, yielding a set
of all-sky flux maps, the auto-correlation and cross-correlation properties of
which are examined in detail. In the second part of the paper, filtering
schemes based on scale-adaptive and matched filtering are extended to spherical
data sets, that enable the amplification of the weak SZ-signal in the presence
of all contaminations stated above. The theory of scale-adaptive and matched
filtering in the framework of spherical maps is developed, the resulting filter
kernel shapes are discussed and their functionality is verified.Comment: 23 pages, 22 figures, 1 table, submitted to MNRAS, 05.Jul.200
Hi-GAL, theHerschelinfrared Galactic Plane Survey: photometric maps and compact source catalogues
Aims. We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500 µm, encompassing the peak of the spectral energy distribution of cold dust for 8 < T < 50 K. This first Hi-GAL data release covers the inner
Milky Way in the longitude range 68◦ > t > −70◦ in a |b| ≤ 1◦ latitude strip. ∼ ∼
∼ ∼
Methods. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and
stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2◦ × 2◦ “tile” that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared.
Results. Hi-GAL DR1 images are cirrus noise limited and reach the 1σ-rms predicted by the Herschel Time Estimators for parallel-mode obser- vations at 6011 s−1 scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source posi- tion, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 123210, 308509, 280685, 160972, and 85460 compact sources in the five bands
Non-Gaussianity in Large Scale Structure and Minkowski Functionals
Minkowski Functionals (MFs) are topological statistics that have become one
of many standard tools used for investigating the statistical properties of
cosmological random fields. They have found regular use in studies of
departures from Gaussianity in a number of important cosmological scenarios.
Important examples include the Cosmic Microwave Background (CMB), weak lensing
studies, 21cm surveys and large scale structure (LSS). To lowest order the MFs
depend on three generalised skewness parameters that can be shown to probe the
bispectrum with differing weights. Recent studies have advocated the use of a
power spectrum associated with the bispectrum, called the skew-spectrum, that
has more power to distinguish between various contributions to the bispectrum
than the conventional formalism adopted when using the Minkowski Functionals.
In this article we review the motivations for studying non-Gaussianity and
emphasize the importance of the momentum dependence of higher order correlators
in investigating both inflationary and early Universe models as well as
analytical models for gravitational instability. We then introduce the
skew-spectra, applied to galaxy surveys, as a tool for investigating various
models for primordial and gravitationally induced non-Gaussianities. We present
analytical expressions for the skew-spectra for the density field and
divergence of the velocity field in 3D and for projected surveys as a function
of redshift and a smoothing angular scale. A Gaussian window function is
assumed throughout this paper. Analytical results are derived for the case of
gravitationally induced non-Gaussianity. These results can be generalised to
incorporate redshift space effects. This will be useful in probing primordial
and gravitationally induced non-Gaussianity from ongoing and future galaxy
surveys.Comment: 24 Pages, 12 figure
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