2,528 research outputs found

    CMB Lensing Power Spectrum Biases from Galaxies and Clusters using High-angular Resolution Temperature Maps

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    The lensing power spectrum from cosmic microwave background (CMB) temperature maps will be measured with unprecedented precision with upcoming experiments, including upgrades to ACT and SPT. Achieving significant improvements in cosmological parameter constraints, such as percent level errors on sigma_8 and an uncertainty on the total neutrino mass of approximately 50 meV, requires percent level measurements of the CMB lensing power. This necessitates tight control of systematic biases. We study several types of biases to the temperature-based lensing reconstruction signal from foreground sources such as radio and infrared galaxies and the thermal Sunyaev-Zel'dovich effect from galaxy clusters. These foregrounds bias the CMB lensing signal due to their non-Gaussian nature. Using simulations as well as some analytical models we find that these sources can substantially impact the measured signal if left untreated. However, these biases can be brought to the percent level if one masks galaxies with fluxes at 150 GHz above 1 mJy and galaxy clusters with masses above M_vir = 10^14 M_sun. To achieve such percent level bias, we find that only modes up to a maximum multipole of l_max ~ 2500 should be included in the lensing reconstruction. We also discuss ways to minimize additional bias induced by such aggressive foreground masking by, for example, exploring a two-step masking and in-painting algorithm.Comment: 14 pages, 14 figures, to be submitted to Ap

    Lamin A/C Haploinsufficiency Modulates the Differentiation Potential of Mouse Embryonic Stem Cells

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    BACKGROUND: Lamins are structural proteins that are the major determinants of nuclear architecture and play important roles in various nuclear functions including gene regulation and cell differentiation. Mutations in the human lamin A gene cause a spectrum of genetic diseases that affect specific tissues. Most available mouse models for laminopathies recapitulate disease symptoms for muscle diseases and progerias. However, loss of human lamin A/C also has highly deleterious effects on fetal development. Hence it is important to understand the impact of lamin A/C expression levels on embryonic differentiation pathways. METHODOLOGY AND PRINCIPAL FINDINGS: We have investigated the differentiation potential of mouse embryonic stem cells containing reduced levels of lamin A/C by detailed lineage analysis of embryoid bodies derived from these cells by culture. We initially carried out a targeted disruption of one allele of the mouse lamin A/C gene (). Undifferentiated wild-type and embryonic stem cells showed similar expression of pluripotency markers and cell cycle profiles. Upon spontaneous differentiation into embryoid bodies, markers for visceral endoderm such as α-fetoprotein were highly upregulated in haploinsufficient cells. However, neuronal markers such as β-III tubulin and nestin were downregulated. Furthermore, we observed a reduction in the commitment of cells into the myogenic lineage, but no discernible effects on cardiac, adipocyte or osteocyte lineages. In the next series of experiments, we derived embryonic stem cell clones expressing lamin A/C short hairpin RNA and examined their differentiation potential. These cells expressed pluripotency markers and, upon differentiation, the expression of lineage-specific markers was altered as observed with embryonic stem cells. CONCLUSIONS: We have observed significant effects on embryonic stem cell differentiation to visceral endoderm, neuronal and myogenic lineages upon depletion of lamin A/C. Hence our results implicate lamin A/C level as an important determinant of lineage-specific differentiation during embryonic development

    Magnetic and axial vector form factors as probes of orbital angular momentum in the proton

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    We have recently examined the static properties of the baryon octet (magnetic moments and axial vector coupling constants) in a generalized quark model in which the angular momentum of a polarized nucleon is partly spin ⟨Sz⟩\langle S_z \rangle and partly orbital ⟨Lz⟩\langle L_z \rangle. The orbital momentum was represented by the rotation of a flux-tube connecting the three constituent quarks. The best fit is obtained with ⟨Sz⟩=0.08±0.15\langle S_z \rangle = 0.08\pm 0.15, ⟨Lz⟩=0.42±0.14\langle L_z \rangle = 0.42\pm 0.14. We now consider the consequences of this idea for the q2q^2-dependence of the magnetic and axial vector form factors. It is found that the isovector magnetic form factor GMisovec(q2)G_M^{\mathrm{isovec}}(q^2) differs in shape from the axial form factor FA(q2)F_A(q^2) by an amount that depends on the spatial distribution of orbital angular momentum. The model of a rigidly rotating flux-tube leads to a relation between the magnetic, axial vector and matter radii, ⟨r2⟩mag=fspin⟨r2⟩axial+52forb⟨r2⟩matt\langle r^2 \rangle_{\mathrm{mag}} = f_{\mathrm{spin}} \langle r^2 \rangle_{\mathrm{axial}} + \frac{5}{2} f_{\mathrm{orb}} \langle r^2 \rangle_{\mathrm{matt}}, where forb/fspin=13⟨Lz⟩/GAf_{\mathrm{orb}}/ f_{\mathrm{spin}} = \frac{1}{3}\langle L_z \rangle / G_A, fspin+forb=1f_{\mathrm{spin}} + f_{\mathrm{orb}} = 1. The shape of FA(q2)F_A(q^2) is found to be close to a dipole with MA=0.92±0.06M_A = 0.92\pm 0.06 GeV.Comment: 18 pages, 5 ps-figures, uses RevTe

    Optimization of influential parameters for extracellular keratinase production of Bacillus subtilis (MTCC9102) in solid state fermentation using horn meal - a biowaste management

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    A Bacillus subtilis (MTCC9102) isolate was shown to produce significant amount of keratinase under optimized conditions in solid-state fermentation using Horn meal as a substrate. Optimized value for moisture, inoculum, and aeration were found to be 100% (v/w), 50% (v/w), and 150% (w/w), respectively, and the optimum nitrogen source was peptone and carbon source was dextrose. Maximum keratinolytic activity was observed at 48 h after incubation, and the optimum age (24 h) of inoculum was significant. The influence of cultivation temperature and initial pH of the medium on keratinase production revealed the optimum values for the temperature and pH as 37°C and 7, respectively. Maximum keratinase activity of the crude extract was 15,972 U/mg/ml. These results indicate that this bacterial strain shows a high biotechnological potential for keratinase production in solid-state fermentation, and use of the horn meal as the substrate can be implemented for keratinous solid wastes management

    Genome-wide association mapping and comparative genomics identifies genomic regions governing grain nutritional traits in finger millet (Eleusine coracana L. Gaertn)

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    Micronutrient deficiency is a serious and underestimated global health concern. Identifying existing micronutritional richness in traditional crops, and breeding this potential into staple crops that are more frequently consumed, could offer a potential low-cost, sustainable solution to micronutrient deficiency. Here, we provide the first insight into genetic control of grain micronutrient content in the staple food crop finger millet ( Eleusine coracana ). Quantifying the existing natural variation in nutritional traits, and identifying the regions of the genome associated with these traits, will underpin future breeding efforts to improve not only global food and nutrition security, but also human health

    Evidence for Non-Hydrostatic Gas from the Cluster X-ray to Lensing Mass Ratio

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    Using a uniform analysis procedure, we measure spatially resolved weak gravitational lensing and hydrostatic X-ray masses for a sample of 18 clusters of galaxies. We find a radial trend in the X-ray to lensing mass ratio: at r2500 we obtain a ratio MX/ML=1.03+/-0.07 which decreases to MX/ML=0.78+/-0.09 at r500. This difference is significant at 3 sigma once we account for correlations between the measurements. We show that correcting the lensing mass for excess correlated structure outside the virial radius slightly reduces, but does not eliminate this trend. An X-ray mass underestimate, perhaps due to nonthermal pressure support, can explain the residual trend. The trend is not correlated with the presence or absence of a cool core. We also examine the cluster gas fraction and find no correlation with ML, an important result for techniques that aim to determine cosmological parameters using the gas fraction.Comment: 8 pages, minor modifications, accepted for publication in MNRA

    Z decays into light gluinos: a calculation based on unitarity

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    The Z boson can decay to a pair of light gluinos through loop-mediated processes. Based on unitarity of the S-matrix, the imaginary part of the decay amplitude is computed in the presence of a light bottom squark. This imaginary part can provide useful information on the full amplitude. Implications are discussed for a recently proposed light gluino and light bottom squark scenario.Comment: 19 pages, LaTeX, 3 figures, submitted to Phys. Rev.

    T-odd correlations in charged Kl4 decays

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    We analyse the sensitivity to physics beyond the SM of T-odd correlations in Kℓ4K_{\ell 4} decays, which do not involve the lepton polarization. We show that a combined analysis of Kμ4+K^+_{\mu 4} and Kμ4−K^-_{\mu 4} decays can lead to new constraints about CP violation in ΔS=1\Delta S=1 charged-current interactions, complementary to those obtained from the transverse muon polarization in Kμ3K_{\mu 3} and of comparable accuracy.Comment: 6 pages (LaTeX

    Vector-meson contributions do not explain the rate and spectrum in K_L -> pi0 gamma gamma

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    We analyze the recent NA48 data for the reaction K_L -> pi0 gamma gamma with and without the assumption of vector meson dominance (VMD). We find that the data is well described by a three-parameter expression inspired by O(p^6) chiral perturbation theory. We also find that it is impossible to fit the shape of the decay distribution and the overall rate simultaneously if one imposes the VMD constraints on the three parameters. We comment on the different fits and their implications for the CP-conserving component of the decay K_L -> pi0 e+ e-.Comment: Version accepted for publication on Phys. Rev. D. 19 pages, LaTeX, 8 figures, uses epsf.st

    Background measurements and detector response studies for ISMRAN experiment

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    We report the measurement of the non-reactor environmental backgrounds and the detector response with the Indian Scintillator Matrix for Reactor Anti-Neutrinos (ISMRAN), which is ∼\sim1 ton detector setup by volume, consisting of 10×\times9 (10 rows and 9 columns) Plastic Scintillator Bars (PSBs) array at BARC, Mumbai, India. ISMRAN is an above-ground anti-neutrino (ν‾e\mathrm{\overline\nu_{e}}) experiment at very short baseline located at Dhruva research reactor facility. It is enclosed by a shielding made of 10 cm thick lead and 10 cm thick borated polyethylene to minimize the backgrounds and is mounted on a movable base structure, situated at ∼\sim 13 m away from the reactor core. These measurements are useful in the context of the ISMRAN detector setup that will be used to detect the reactor ν‾e\mathrm{\overline\nu_{e}} and measure its energy spectrum through the inverse beta decay (IBD) process. In this paper, we present the energy resolution model and energy non-linearity model of PSB and the cosmogenic muon-induced background, based on the sum of their energy depositions and number of hit bars. Reconstructed sum energy spectrum and number of hit bars distribution for 22Na\mathrm{{}^{22}Na} radioactive source has been compared with Geant4 based Monte Carlo simulations. These experimentally measured results will be useful for discriminating the correlated and uncorrelated background events from the true IBD events in reactor ON and OFF conditions inside the reactor hall.Comment: 4 pages, 4 figures. arXiv admin note: text overlap with arXiv:2208.0349
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