ABSTRACT
In this paper, we predict the covariance matrices of both the power spectrum and the bispectrum, including full non-Gaussian contributions, redshift space distortions, linear bias effects, ...and shot-noise corrections, using perturbation theory (PT). To quantify the redshift-space distortion effect, we focus mainly on the monopole and quadrupole components of both the power and bispectra. We, for the first time, compute the 5- and 6-point spectra to predict the cross-covariance between the power and bispectra, and the autocovariance of the bispectrum in redshift space. We test the validity of our calculations by comparing them with the covariance matrices measured from the MultiDark-Patchy mock catalogues that are designed to reproduce the galaxy clustering measured from the Baryon Oscillation Spectroscopic Survey Data Release 12. We argue that the simple, leading-order PT works because the shot-noise corrections for the Patchy mocks are more dominant than other higher order terms we ignore. In the meantime, we confirm some discrepancies in the comparison, especially of the cross-covariance. We discuss potential sources of such discrepancies. We also show that our PT model reproduces well the cumulative signal-to-noise ratio of the power spectrum and the bispectrum as a function of maximum wavenumber, implying that our PT model captures successfully essential contributions to the covariance matrices.
Modeling the reconstructed BAO in Fourier space Seo, Hee-Jong; Beutler, Florian; Ross, Ashley J ...
Monthly notices of the Royal Astronomical Society,
08/2016, Letnik:
460, Številka:
3
Journal Article
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Odprti dostop
The density field reconstruction technique, which partially reverses the non-linear degradation of the Baryon acoustic oscillation (BAO) feature in the galaxy redshift surveys, has been successful in ...substantially improving the cosmology constraints from recent surveys such as Baryon Oscillation Spectroscopic Survey (BOSS). We estimate the efficiency of the method as a function of various reconstruction details. To directly quantify the BAO information in non-linear density fields before and after reconstruction, we calculate the cross-correlations (i.e. propagators) of the pre(post)-reconstructed density field with the initial linear field using a mock sample that mimics the clustering of the BOSS galaxies. The results directly provide the BAO damping as a function of wavenumber that can be implemented into the Fisher matrix analysis. We focus on investigating the dependence of the propagator on a choice of smoothing filters and on two major different conventions of the redshift-space density field reconstruction that have been used in literature. By estimating the BAO signal to noise for each case, we predict constraints on the angular diameter distance and Hubble parameter using the Fisher matrix analysis. We thus determine an optimal Gaussian smoothing filter scale for the signal-to-noise level of the BOSS CMASS. We also present appropriate BAO fitting models for different reconstruction methods based on the first- and second-order Lagrangian perturbation theory in Fourier space. Using the mock data, we show that the modified BAO fitting model can substantially improve the accuracy of the BAO position in the best fits as well as the goodness of the fits.
Negative segregation beneath the surface of the slab is generated by the flow of molten steel in continuous casting. Negative segregation of austenite stabilizing elements such as Ni and C results in ...the formation of delta ferrite, which can cause cracks near the slab surface in austenitic stainless steel. In the current study, we developed a numerical simulation model to predict negative segregation in the continuous casting process. The model used an effective distribution coefficient that is dependent on the solidification rate and the liquid velocity in front of a solidifying shell. A comparison of the numerical simulation and the experimental results for the solidification in a crucible with a rotating and cooling pipe indicated the validity of the proposed numerical simulation model. Additionally, the numerical simulation results of continuous casting for austenitic stainless steel showed that the maximum degree of negative segregation occurred near the slab corners when casting at high speed with electromagnetic stirrer. The degree and location of negative segregation in the numerical simulation were comparable to those obtained from EPMA and Spark-OES analysis of slab samples. These results indicated that the proposed simulation model enables accurate prediction of negative segregation beneath the slab surface in continuous casting and is useful for the optimization of continuous casting process. The negative segregation was caused by the molten steel flow in front of a solidifying shell. Consequently, the results from simulation without EMS or at low casting speeds showed that negative segregation was suppressed.
The gel-phase domains in a binary supported lipid bilayer (SLB) comprising dioleoylphosphatidylcholine (DOPC) and dipalmitoylphosphatidylcholine (DPPC) were localized on graphene oxide (GO) deposited ...on a SiO
/Si substrate. We investigated the distribution of the gel-phase domains and the liquid crystalline (L
) phase regions in DOPC+DPPC-SLB on thermally oxidized SiO
/Si substrates with GO flakes to understand the mechanism of the domain localization on GO. Fluorescence microscopy and atomic force microscopy revealed that the gel-phase domains preferably distributed on GO flakes, whereas the fraction of the L
-phase increased on the bare SiO
surface which was not covered with the GO flakes. The gel-phase domain was condensed on GO more effectively at the lower cooling rate. We propose that nucleation of the gel-phase domain preferentially occurred on GO, whose surface has amphiphilic property, during the gel-phase domain formation. The domains of the liquid ordered (L
) phase were also condensed on GO in a ternary bilayer containing cholesterol that was phase-separated to the L
phase and the liquid disordered phase. Rigid domains segregates on GO during their formation process, leaving fluid components to the surrounding region of GO.
Abstract
We present high signal-to-noise galaxy–galaxy lensing measurements of the Baryon Oscillation Spectroscopic Survey constant mass (CMASS) sample using 250 deg2 of weak-lensing data from ...Canada–France–Hawaii Telescope Lensing Survey and Canada–France–Hawaii Telescope Stripe 82 Survey. We compare this signal with predictions from mock catalogues trained to match observables including the stellar mass function and the projected and two-dimensional clustering of CMASS. We show that the clustering of CMASS, together with standard models of the galaxy–halo connection, robustly predicts a lensing signal that is 20–40 per cent larger than observed. Detailed tests show that our results are robust to a variety of systematic effects. Lowering the value of
$S_{\rm 8}=\sigma _{\rm 8} \sqrt{\Omega _{\rm m}/0.3}$
compared to Planck Collaboration XIII reconciles the lensing with clustering. However, given the scale of our measurement (r < 10 h
−1 Mpc), other effects may also be at play and need to be taken into consideration. We explore the impact of baryon physics, assembly bias, massive neutrinos and modifications to general relativity on ΔΣ and show that several of these effects may be non-negligible given the precision of our measurement. Disentangling cosmological effects from the details of the galaxy–halo connection, the effect of baryons, and massive neutrinos, is the next challenge facing joint lensing and clustering analyses. This is especially true in the context of large galaxy samples from Baryon Acoustic Oscillation surveys with precise measurements but complex selection functions.
A rare actinomycetal strain of the genus Actinomycetospora was found to produce a new tryptophan derivative, designated mycetoindole (1). The structure of 1 was determined to be N-3-methylcrotonoyl ...(Z)-dehydrotryptophan by NMR and MS analytical methods. Compound 1 reduced the root growth of lettuce Lactuca sativa seedlings at concentrations above 0.1 μM and almost completely inhibited seed germination at 10 μM.
In actinomycetes, many secondary metabolite biosynthetic genes are not expressed under typical laboratory culture conditions and various efforts have been made to activate these dormant genes. In ...this study, we focused on high-temperature culture. First, we examined the thermotolerance of 3160 actinomycete strains from our laboratory culture collection and selected 57 thermotolerant actinomycetes that grew well at 45 °C. These 57 thermotolerant actinomycetes were cultured for 5 days in liquid medium at both 30 °C and 45 °C. Culture broths were extracted with 1-butanol, and each extract was subjected to LC/MS analysis. The metabolic profiles of each strain were compared between the 30 °C and 45 °C cultures. We found that almost half of these thermotolerant actinomycetes produced secondary metabolites that were detected only in the 45 °C culture. This result suggests that high-temperature culture induces the production of dormant secondary metabolites. These compounds were named "heat shock metabolites (HSMs)." To examine HSM production in more detail, 18 strains were selected at random from the initial 57 strains and cultivated in six different media at 30 °C and 45 °C; as before, metabolic profiles of each strain in each medium were compared between the 30 °C and 45 °C cultures. From this analysis, we found a total of 131 HSMs. We identified several angucycline-related compounds as HSMs from two thermotolerant Streptomyces species. Furthermore, we discovered a new compound, murecholamide, as an HSM from thermotolerant Streptomyces sp. AY2. We propose that high-temperature culture of actinomycetes is a convenient method for activating dormant secondary metabolite biosynthetic genes.
We investigate the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12 sample, which consists of 1198 006 galaxies in the redshift range 0.2 < z < 0.75 and a ...sky coverage of 10 252 deg2. We analyse this data set in Fourier space, using the power-spectrum multipoles to measure redshift-space distortions simultaneously with the Alcock-Paczynski effect and the baryon acoustic oscillation scale. We include the power-spectrum monopole, quadrupole and hexadecapole in our analysis and compare our measurements with a perturbation-theory-based model, while properly accounting for the survey window function. To evaluate the reliability of our analysis pipeline, we participate in a mock challenge, which results in systematic uncertainties significantly smaller than the statistical uncertainties. While the high-redshift constraint on fs8 at zeff = 0.61 indicates a small (~1.4s) deviation from the prediction of the Planck ...CDM (... cold dark matter) model, the low-redshift constraint is in good agreement with Planck ...CDM. This paper is part of a set that analyses the final galaxy clustering data set from BOSS. The measurements and likelihoods presented here are combined with others in Alam et al. to produce the final cosmological constraints from BOSS. (ProQuest: ... denotes formulae/symbols omitted.)
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