2,208 research outputs found
CMB lensing with shear-only reconstruction on the full sky
Reconstruction of gravitational lensing effects in the CMB from current and
upcoming surveys is still dominated by temperature anisotropies. Extragalactic
foregrounds in temperature maps can induce significant biases in the lensing
power spectrum obtained with the standard quadratic estimators. Techniques such
as masking cannot remove these foregrounds fully, and the residuals can still
lead to large biases if unaccounted for. In this paper, we study the
"shear-only" estimator, an example of a class of geometric methods that
suppress extragalactic foreground contamination while making only minimal
assumptions about foreground properties. The shear-only estimator has only been
formulated in the flat-sky limit and so is not easily applied to wide surveys.
Here, we derive the full-sky version of the shear-only estimator and its
generalisation to an multipole estimator that has improved performance
for lensing reconstruction on smaller scales. The multipole estimator is
generally not separable, and so is expensive to compute. We explore separable
approximations based on a singular-value decomposition, which allow efficient
evaluation of the estimator with real-space methods. Finally, we apply these
estimators to simulations that include extragalactic foregrounds and verify
their efficacy in suppressing foreground biases.Comment: v2 matches with published versio
Probing early structure and model-independent neutrino mass with high-redshift CMB lensing mass maps
CMB lensing maps probe the mass distribution in projection out to high
redshifts, but significant sensitivity to low-redshift structure remains. In
this paper we discuss a method to remove the low-redshift contributions from
CMB lensing mass maps by subtracting suitably scaled galaxy density maps,
nulling the low redshift structure with a model-insensitive procedure that is
similar to delensing. This results in a high--only mass map that can provide
a probe of structure growth at uniquely high redshifts: if systematics can be
controlled, we forecast that CMB-S4 lensing combined with a Rubin-LSST-like
galaxy survey can probe the amplitude of structure at redshifts
() to within (). We then discuss other example applications
of such high- CMB lensing maps. In standard analyses of CMB lensing,
assuming the wrong dark energy model (or wrong model parametrization) can lead
to biases in neutrino mass constraints. In contrast, we show with forecasts
that a high- mass map constructed from CMB-S4 lensing and LSST galaxies can
provide a nearly model-independent neutrino mass constraint, with only
negligible sensitivity to the presence of non-standard dark energy models,
irrespective of their parametrization.Comment: 19 pages, 11 figure
Activation of intestinal human pregnane X receptor protects against azoxymethane/dextran sulfate sodium-induced colon cancer
Number of text pages: 25 Number of tables: 0 Number of figures: 8 Number of references: 24 Number of words i
Rms-flux relation of Cyg X-1 with RXTE: dipping and nondipping cases
The rms (root mean square) variability is the parameter for understanding the
emission temporal properties of X-ray binaries (XRBs) and active galactic
nuclei (AGN).
The rms-flux relation with Rossi X-ray Timing Explorer (RXTE) data for the
dips and nondip of black hole Cyg X-1 has been investigated in this paper. Our
results show that there exist the linear rms-flux relations in the frequency
range 0.1-10 Hz for the dipping light curve. Moreover, this linear relation
still remains during the nondip regime, but with the steeper slope than that of
the dipping case in the low energy band. For the high energy band, the slopes
of the dipping and nondipping cases are hardly constant within errors. The
explanations of the results have been made by means of the ``Propagating
Perturbation'' model of Lyubarskii (1997).Comment: 15 pages, 12 figures, Accepted for publication in Astrophysics &
Space Scienc
Activation of Intestinal Human Pregnane X Receptor Protects against Azoxymethane/Dextran Sulfate Sodium-Induced Colon Cancer s
ABSTRACT The role of intestinal human pregnane X receptor (PXR) in colon cancer was determined through investigation of the chemopreventive role of rifaximin, a specific agonist of intestinal human PXR, toward azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced colon cancer. Rifaximin treatment significantly decreased the number of colon tumors induced by AOM/DSS treatment in PXR-humanized mice, but not wild-type or Pxr-null mice. Additionally, rifaximin treatment markedly increased the survival rate of PXR-humanized mice, but not wild-type or Pxr-null mice. These data indicated a human PXR-dependent therapeutic chemoprevention of rifaximin toward AOM/DSS-induced colon cancer. Nuclear factor k-light-chain-enhancer of activated B cells-mediated inflammatory signaling was upregulated in AOM/DSS-treated mice, and inhibited by rifaximin in PXRhumanized mice. Cell proliferation and apoptosis were also modulated by rifaximin treatment in the AOM/DSS model. In vitro cell-based assays further revealed that rifaximin regulated cell apoptosis and cell cycle in a human PXR-dependent manner. These results suggested that specific activation of intestinal human PXR exhibited a chemopreventive role toward AOM/DSS-induced colon cancer by mediating anti-inflammation, antiproliferation, and proapoptotic events
Role of CCR8 and Other Chemokine Pathways in the Migration of Monocyte-derived Dendritic Cells to Lymph Nodes
Studying the influence of chemokine receptors (CCRs) on monocyte fate may reveal information about which subpopulations of monocytes convert to dendritic cells (DCs) and the migration pathways that they use. First, we examined whether prominent CCRs on different monocyte subsets, CCR2 or CX3CR1, mediated migration events upstream of the accumulation of monocyte-derived DCs in lymph nodes (LNs). Monocytes were labeled and traced by uptake of latex microspheres in skin. Unexpectedly, neither CCR2 nor CX3CR1 were required. However, absence of CCR2 led to an increased labeling of the minor Gr-1int monocyte population, and the number of latex+ DCs that emigrated to LNs was correspondingly increased. Characterization of Gr-1int monocytes revealed that they selectively expressed CCR7 and CCR8 mRNA in blood. CCR7 and CCR8 pathways were used by monocyte-derived DCs during mobilization from skin to LNs. The role of CCR8 in emigration from tissues also applied to human monocyte-derived cells in a model of transendothelial trafficking. Collectively, the data suggest that Gr-1int monocytes may be most disposed to become a lymphatic-migrating DCs. When these monocyte-derived DCs exit skin to emigrate to LNs, they use not only CCR7 but also CCR8, which was not previously recognized to participate in migration to LNs
Single-molecule experiments in biological physics: methods and applications
I review single-molecule experiments (SME) in biological physics. Recent
technological developments have provided the tools to design and build
scientific instruments of high enough sensitivity and precision to manipulate
and visualize individual molecules and measure microscopic forces. Using SME it
is possible to: manipulate molecules one at a time and measure distributions
describing molecular properties; characterize the kinetics of biomolecular
reactions and; detect molecular intermediates. SME provide the additional
information about thermodynamics and kinetics of biomolecular processes. This
complements information obtained in traditional bulk assays. In SME it is also
possible to measure small energies and detect large Brownian deviations in
biomolecular reactions, thereby offering new methods and systems to scrutinize
the basic foundations of statistical mechanics. This review is written at a
very introductory level emphasizing the importance of SME to scientists
interested in knowing the common playground of ideas and the interdisciplinary
topics accessible by these techniques. The review discusses SME from an
experimental perspective, first exposing the most common experimental
methodologies and later presenting various molecular systems where such
techniques have been applied. I briefly discuss experimental techniques such as
atomic-force microscopy (AFM), laser optical tweezers (LOT), magnetic tweezers
(MT), biomembrane force probe (BFP) and single-molecule fluorescence (SMF). I
then present several applications of SME to the study of nucleic acids (DNA,
RNA and DNA condensation), proteins (protein-protein interactions, protein
folding and molecular motors). Finally, I discuss applications of SME to the
study of the nonequilibrium thermodynamics of small systems and the
experimental verification of fluctuation theorems. I conclude with a discussion
of open questions and future perspectives.Comment: Latex, 60 pages, 12 figures, Topical Review for J. Phys. C (Cond.
Matt
The Atacama Cosmology Telescope: Cosmology from cross-correlations of unWISE galaxies and ACT DR6 CMB lensing
We present tomographic measurements of structure growth using
cross-correlations of Atacama Cosmology Telescope (ACT) DR6 and Planck CMB
lensing maps with the unWISE Blue and Green galaxy samples, which span the
redshift ranges and , respectively. We improve on prior unWISE cross-correlations not just by
making use of the new, high-precision ACT DR6 lensing maps, but also by
including additional spectroscopic data for redshift calibration and by
analysing our measurements with a more flexible theoretical model. An extensive
suite of systematic and null tests within a blind analysis framework ensures
that our results are robust. We determine the amplitude of matter fluctuations
at low redshifts (), finding using the ACT cross-correlation alone and with a combination of Planck and ACT cross-correlations; these
measurements are fully consistent with the predictions from primary CMB
measurements assuming standard structure growth. The addition of Baryon
Acoustic Oscillation data breaks the degeneracy between and
, allowing us to measure from the
cross-correlation of unWISE with ACT and from the
combination of cross-correlations with ACT and Planck. These results also agree
with the expectations from primary CMB extrapolations in CDM
cosmology; the consistency of derived from our two redshift samples
at and provides a further check of our cosmological model.
Our results suggest that structure formation on linear scales is well described
by CDM even down to low redshifts .Comment: 73 pages (incl. 30 pages of appendices), 50 figures, 16 tables, to be
submitted to ApJ. Watch G. S. Farren and A. Krolewski discuss the analysis
and results under https://cosmologytalks.com/2023/09/11/act-unwis
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