Galaxies are biased tracers of the matter density on cosmological scales. For future tests of galaxy models, we refine and assess a method to measure galaxy biasing as a function of physical scale k ...with weak gravitational lensing. This method enables us to reconstruct the galaxy bias factor b(k) as well as the galaxy-matter correlation r(k) on spatial scales between 0.01 h Mpc−1 ≲ k ≲ 10 h Mpc−1 for redshift-binned lens galaxies below redshift z ≲ 0.6. In the refinement, we account for an intrinsic alignment of source ellipticities, and we correct for the magnification bias of the lens galaxies, relevant for the galaxy-galaxy lensing signal, to improve the accuracy of the reconstructed r(k). For simulated data, the reconstructions achieve an accuracy of 3–7% (68% confidence level) over the above k-range for a survey area and a typical depth of contemporary ground-based surveys. Realistically the accuracy is, however, probably reduced to about 10–15%, mainly by systematic uncertainties in the assumed intrinsic source alignment, the fiducial cosmology, and the redshift distributions of lens and source galaxies (in that order). Furthermore, our reconstruction technique employs physical templates for b(k) and r(k) that elucidate the impact of central galaxies and the halo-occupation statistics of satellite galaxies on the scale-dependence of galaxy bias, which we discuss in the paper. In a first demonstration, we apply this method to previous measurements in the Garching-Bonn Deep Survey and give a physical interpretation of the lens population.
Background Despite the high prevalence and morbidity of chronic rhinosinusitis (CRS), little is known about the mechanisms that underlie its pathogenesis. Recent studies have suggested that B cells ...might play an important role in CRS. Objective We sought to thoroughly characterize B lineage cells within sinus tissues of patients with CRS and healthy control subjects and to determine whether levels of EBV-induced protein 2, which is known to play an important role in the development of B-cell responses, were increased in patients with CRS. Methods Cells isolated from sinus tissues of patients with CRS and healthy control subjects were characterized by means of flow cytometry and immunohistochemistry. Local production of antibodies was measured in tissue extracts, nasal lavage fluid, and sera by using multiplex bead arrays and ELISA. Quantitative RT-PCR, ELISA, and Western blotting were used to assess gene and protein expression from tissue extracts. Results Nasal polyps (NPs) from patients with CRS had increased levels of both B cells and plasma cells compared with uncinate tissue from healthy control subjects ( P < .05). NPs also contained significantly increased levels of several antibody isotypes compared with normal uncinate tissue ( P < .05), but no differences in circulating antibody levels were found. Interestingly, levels of EBV-induced protein 2 were also increased in NPs ( P < .05) and were positively correlated with expression of plasma cell markers (CD138 and B lymphocyte–induced maturation protein) in sinus tissue. Conclusion B cells and plasma cells are enriched in NPs, actively produce antibodies locally, and might contribute to chronic inflammation in patients with CRS. Elucidating the mechanisms that underlie this excessive local B-cell response might provide novel insights for the development of improved therapeutic strategies.
Mechanoelectric feedback (MEF) describes the modulation of electrical activity by mechanical activity. This may occur via the activation of mechanosensitive ion channels (MSCs). MEF has not ...previously been investigated in fish ventricular tissue even though fish can greatly increase ventricular end diastolic volume during exercise which should therefore provide a powerful mechanical stimulus for MEF.
When the ventricles of extrinsically paced, isolated working trout hearts were dilated by increasing afterload, monophasic action potential (MAP) duration was significantly shortened at 25% repolarisation, unaltered at 50% repolarisation and significantly lengthened at 90% repolarisation. This observation is consistent with the activation of cationic non-selective MSCs (MSC(NS)s). We then cloned the trout ortholog of TRPC1, a candidate MSC(NS) and confirmed its presence in the trout heart.
Our results have validated the use of MAP technology for the fish heart and suggest that, in common with amphibians and mammals, MEF operates in fish ventricular myocardium, possibly via the activation of mechanosensitive TRPC1 ion channels.
Galaxy models predict a tight relation between the clustering of galaxies and dark matter on cosmological scales, but predictions differ notably in the details. We used this opportunity and tested ...two semi-analytic models by the Munich and Durham groups with data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). For the test we measured the scale-dependent galaxy bias factor b(k) and correlation factor r(k) from linear to non-linear scales of k ≈ 10 h Mpc−1 at two redshifts z̄ = 0.35, 0.51 for galaxies with stellar mass between 5 × 109 and 3 × 1011 h70−2 M⊙. Our improved gravitational lensing technique accounts for the intrinsic alignment of sources and the magnification of lens galaxies for better constraints for the galaxy-matter correlation r(k). Galaxy bias in CFHTLenS increases with k and stellar mass; it is colour-dependent, revealing the individual footprints of galaxy types. Despite a reasonable model agreement for the relative change with both scale and galaxy properties, there is a clear conflict for b(k) with no model preference: the model galaxies are too weakly clustered. This may flag a model problem at z ≳ 0.3 for all stellar masses. As in the models, however, there is a high correlation r(k) between matter and galaxy density on all scales, and galaxy bias is typically consistent with a deterministic bias on linear scales. Only our blue and low-mass galaxies of about 7 × 109 h70−2 M⊙ at z̄ = 0.51 show, contrary to the models, a weak tendency towards a stochastic bias on linear scales where rls = 0.75 ± 0.14 (stat.) ± 0.06 (sys.). This result is of interest for cosmological probes, such as EG, that rely on a deterministic galaxy bias. We provide Monte Carlo realisations of posterior constraints for b(k) and r(k) in CFHTLenS for every galaxy sample in this paper at the CDS.
Galaxy models predict a tight relation between the clustering of galaxies and dark matter on cosmological scales, but predictions differ notably in the details. We used this opportunity and tested ...two semi-analytic models by the Munich and Durham groups with data from the Canada-France-Hawaii Telescope Lensing Survey (CFHTLenS). For the test we measured the scale-dependent galaxy bias factor
b
(
k
) and correlation factor
r
(
k
) from linear to non-linear scales of
k
≈ 10
h
Mpc
−1
at two redshifts
z̄
= 0.35, 0.51 for galaxies with stellar mass between 5 × 10
9
and 3 × 10
11
h
70
−2
M
⊙
. Our improved gravitational lensing technique accounts for the intrinsic alignment of sources and the magnification of lens galaxies for better constraints for the galaxy-matter correlation
r
(
k
). Galaxy bias in CFHTLenS increases with
k
and stellar mass; it is colour-dependent, revealing the individual footprints of galaxy types. Despite a reasonable model agreement for the relative change with both scale and galaxy properties, there is a clear conflict for
b
(
k
) with no model preference: the model galaxies are too weakly clustered. This may flag a model problem at
z
≳ 0.3 for all stellar masses. As in the models, however, there is a high correlation
r
(
k
) between matter and galaxy density on all scales, and galaxy bias is typically consistent with a deterministic bias on linear scales. Only our blue and low-mass galaxies of about 7 × 10
9
h
70
−2
M
⊙
at
z̄
= 0.51 show, contrary to the models, a weak tendency towards a stochastic bias on linear scales where
r
ls
= 0.75 ± 0.14 (stat.) ± 0.06 (sys.). This result is of interest for cosmological probes, such as
E
G
, that rely on a deterministic galaxy bias. We provide Monte Carlo realisations of posterior constraints for
b
(
k
) and
r
(
k
) in CFHTLenS for every galaxy sample in this paper at the CDS.
Life on Earth anticipates recurring 24-hour environmental cycles via genetically encoded molecular clocks active in all mammalian organs. Communication between these clocks controls circadian ...homeostasis. Intertissue communication is mediated, in part, by temporal coordination of metabolism. Here, we characterize the extent to which clocks in different organs control systemic metabolic rhythms, an area that remains largely unexplored. We analyzed the metabolome of serum from mice with tissue-specific expression of the clock gene
. Having functional hepatic and muscle clocks can only drive a minority (13%) of systemic metabolic rhythms. Conversely, limiting
expression to the central pacemaker in the brain restores rhythms to 57% of circulatory metabolites. Rhythmic feeding imposed on clockless mice resulted in a similar rescue, indicating that the central clock mainly regulates metabolic rhythms via behavior. These findings explicate the circadian communication between tissues and highlight the importance of the central clock in governing those signals.
A Way to DAI Welz, Patrick-Simon; Pasparakis, Manolis
Cell host & microbe,
03/2012, Letnik:
11, Številka:
3
Journal Article
Recenzirano
Odprti dostop
RIP3-regulated necrosis has recently emerged as an important antiviral host defense mechanism. A new study by Upton et al. (2012) identifies DAI, a cytoplasmic DNA sensor, as a partner of RIP3 that ...is essential for the induction of regulated necrosis in cytomegalovirus-infected cells.
Abstract Fish myocytes continue to develop active tension when stretched to sarcomere lengths (SLs) on the descending limb of the mammalian length–tension relationship. A greater length-dependent ...activation in fish than mammals could account for this because the increase in Ca2+ sensitivity may overcome the tendency for force to fall due to reduced cross-bridge availability at SLs above optimal myofilament overlap. We stretched skinned fish and rat ventricular myocytes over a wide range of SLs, including those on the descending limb of the mammalian length–tension relationship. We found that fish myocytes developed greater active tension than rat myocytes at physiological Ca2+ concentrations at long SLs as a result of a higher Ca2+ sensitivity and a steeper relationship between Ca2+ sensitivity and SL. We also investigated the diastolic properties of fish and rat myocytes at long SLs by measuring titin-based passive tension, titin isoform expression and titin phosphorylation. Fish myocytes produced higher titin-based passive tension despite expressing a higher proportion of a long N2BA-like isoform (38.0 ± 2% of total vs 0% in rat). However, titin phosphorylation in fish myocytes was lower than in rat, which may explain some of the difference in passive tension between species. The high level of titin-based passive tension and the differential phosphorylation of sarcomeric proteins in fish myocytes may contribute to the enhanced length-dependent activation and underlie the extended range of in vivo stroke volumes found in fish compared with mammals.
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