Experimental demonstration of higher-order Laguerre-Gauss mode interferometry

The compatibility of higher-order Laguerre-Gauss (LG) modes with interferometric technologies commonly used in gravitational wave detectors is investigated. In this paper we present the first experimental results concerning the performance of the LG33 mode in optical resonators. We show that the Pound-Drever-Hall error signal for a LG33 mode in a linear optical resonator is identical to that of the more commonly used LG00 mode, and demonstrate the feedback control of the resonator with a LG33 mode. We succeeded to increase the mode purity of a LG33 mode generated using a spatial-light modulator from 51% to 99% upon transmission through a linear optical resonator. We further report the experimental verification that a triangular optical resonator does not transmit helical LG modes

A census of cool core galaxy clusters in IllustrisTNG

The thermodynamic structure of hot gas in galaxy clusters is sensitive to astrophysical processes and typically difficult to model with galaxy formation simulations. We explore the fraction of cool-core (CC) clusters in a large sample of $370$ clusters from IllustrisTNG, examining six common CC definitions. IllustrisTNG produces continuous CC criteria distributions, the extremes of which are classified as CC and non-cool-core (NCC), and the criteria are increasingly correlated for more massive clusters. At $z=0$, the CC fractions for $2$ criteria are in reasonable agreement with the observed fractions but the other $4$ CC fractions are lower than observed. This result is partly driven by systematic differences between the simulated and observed gas fraction profiles. The simulated CC fractions with redshift show tentative agreement with the observed fractions, but linear fits demonstrate that the simulated evolution is steeper than observed. The conversion of CCs to NCCs appears to begin later and act more rapidly in the simulations. Examining the fraction of CCs and NCCs defined as relaxed we find no evidence that CCs are more relaxed, suggesting that mergers are not solely responsible for disrupting CCs. A comparison of the median thermodynamic profiles defined by different CC criteria shows that the extent to which they evolve in the cluster core is dependent on the CC criteria. We conclude that the thermodynamic structure of galaxy clusters in IllustrisTNG shares many similarities with observations, but achieving better agreement most likely requires modifications of the underlying galaxy formation model.Comment: 24 pages, 17 figures, MNRAS published version. The IllustrisTNG project website can be found at http://www.tng-project.org

Acclimatory responses of the Daphnia pulex proteome to environmental changes. II. Chronic exposure to different temperatures (10 and 20°C) mainly affects protein metabolism

<p>Abstract</p> <p>Background</p> <p>Temperature affects essentially every aspect of the biology of poikilothermic animals including the energy and mass budgets, activity, growth, and reproduction. While thermal effects in ecologically important groups such as daphnids have been intensively studied at the ecosystem level and at least partly at the organismic level, much less is known about the molecular mechanisms underlying the acclimation to different temperatures. By using 2D gel electrophoresis and mass spectrometry, the present study identified the major elements of the temperature-induced subset of the proteome from differently acclimated <it>Daphnia pulex</it>.</p> <p>Results</p> <p>Specific sets of proteins were found to be differentially expressed in 10°C or 20°C acclimated <it>D. pulex</it>. Most cold-repressed proteins comprised secretory enzymes which are involved in protein digestion (trypsins, chymotrypsins, astacin, carboxypeptidases). The cold-induced sets of proteins included several vitellogenin and actin isoforms (cytoplasmic and muscle-specific), and an AAA+ ATPase. Carbohydrate-modifying enzymes were constitutively expressed or down-regulated in the cold.</p> <p>Conclusion</p> <p>Specific sets of cold-repressed and cold-induced proteins in <it>D. pulex </it>can be related to changes in the cellular demand for amino acids or to the compensatory control of physiological processes. The increase of proteolytic enzyme concentration and the decrease of vitellogenin, actin and total protein concentration between 10°C and 20°C acclimated animals reflect the increased amino-acids demand and the reduced protein reserves in the animal's body. Conversely, the increase of actin concentration in cold-acclimated animals may contribute to a compensatory mechanism which ensures the relative constancy of muscular performance. The sheer number of peptidase genes (serine-peptidase-like: > 200, astacin-like: 36, carboxypeptidase-like: 30) in the <it>D. pulex </it>genome suggests large-scaled gene family expansions that might reflect specific adaptations to the lifestyle of a planktonic filter feeder in a highly variable aquatic environment.</p

Gas-phase metallicity gradients of TNG50 star-forming galaxies

We present the radial gas-phase, mass-weighted metallicity profiles and gradients of the TNG50 star-forming galaxy population measured at redshifts $z=$ 0--3. We investigate the redshift evolution of gradients and examine relations between gradient steepness and galaxy properties. We find that TNG50 gradients are predominantly negative at all redshifts, although we observe significant diversity among these negative gradients. We determine that the gradient steepness of all galaxies increases approximately monotonically with redshift at a roughly constant rate. This rate does not vary significantly with galaxy mass. We observe a weak negative correlation between gradient steepness and galaxy stellar mass at redshifts $z\leq2$. However, when we normalize gradients by a characteristic radius defined by the galactic star formation distribution, we find that these normalized gradients remain invariant with both stellar mass and redshift. We place our results in the context of previous simulations and show that TNG50 high-redshift gradients are steeper than those of models featuring burstier feedback, which may further highlight high-redshift gradients as important discriminators of galaxy formation models. We also find that redshift $z=0$ and $z=0.5$ TNG50 gradients are consistent with the gradients observed in galaxies at these redshifts, although the preference for flat gradients observed in redshift $z\gtrsim1$ galaxies is not present in TNG50. If future JWST and ELT observations validate these flat gradients, it may indicate a need for simulation models to implement more powerful radial gas mixing within the ISM, possibly via turbulence and/or stronger windsComment: 24 pages, 14 figures, submitted to MNRA

Enhancing AGN efficiency and cool-core formation with anisotropic thermal conduction

Understanding how baryonic processes shape the intracluster medium (ICM) is of critical importance to the next generation of galaxy cluster surveys. However, most models of structure formation neglect potentially important physical processes, like anisotropic thermal conduction (ATC). In this letter, we explore the impact of ATC on the prevalence of cool-cores (CCs) using 12 pairs of magnetohydrodynamical galaxy cluster simulations, simulated using the IllustrisTNG model with and without ATC. Although the impact of ATC varies from cluster to cluster and with CC criterion, its inclusion produces a systematic shift to larger CC fractions at z = 0 for all CC criteria considered. Additionally, the inclusion of ATC yields a flatter CC fraction redshift evolution, easing the tension with the observed evolution. With ATC included, the energy required for the central black hole to achieve self-regulation is reduced and the gas fraction in the cluster core increases, resulting in larger CC fractions. ATC makes the ICM unstable to perturbations and the increased efficiency of AGN feedback suggests that its inclusion results in a greater level of mixing in the ICM. Therefore, ATC is potentially an important physical process in reproducing the thermal structure of the ICM.Comment: 5 pages, 4 figures, submitted to MNRAS, comments welcom

Analysis of IL2/IL21 Gene Variants in Cholestatic Liver Diseases Reveals an Association with Primary Sclerosing Cholangitis

Background/Aims: The chromosome 4q27 region harboring IL2 and IL21 is an established risk locus for ulcerative colitis (UC) and various other autoimmune diseases. Considering the strong coincidence of primary sclerosing cholangitis (PSC) with UC and the increased frequency of other autoimmune disorders in patients with primary biliary cirrhosis (PBC), we investigated whether genetic variation in the IL2/IL21 region may also modulate the susceptibility to these two rare cholestatic liver diseases. Methods: Four strongly UC-associated single nucleotide polymorphisms (SNPs) within the KIAA1109/TENR/IL2/IL21 linkage disequilibrium block were genotyped in 124 PBC and 41 PSC patients. Control allele frequencies from 1,487 healthy, unrelated Caucasians were available from a previous UC association study. Results: The minor alleles of all four markers were associated with a decreased susceptibility to PSC (rs13151961: p = 0.013, odds ratio (OR) 0.34; rs13119723: p = 0.023, OR 0.40; rs6822844: p = 0.031, OR 0.41; rs6840978: p = 0.043, OR 0.46). Moreover, a haplotype consisting of the four minor alleles also had a protective effect on PSC susceptibility (p = 0.0084, OR 0.28). A haplotype of the four major alleles was independently associated with PSC when excluding the patients with concomitant inflammatory bowel disease (p = 0.033, OR 4.18). Conclusion: The IL2/IL21 region may be one of the highly suggestive but so far rarely identified shared susceptibility loci for PSC and UC. Copyright (C) 2011 S. Karger AG, Base

Searching for non-Gaussianity in the VSA data

We have tested Very Small Array (VSA) observations of three regions of sky for the presence of non-Gaussianity, using high-order cumulants, Minkowski functionals, a wavelet-based test and a Bayesian joint power spectrum/non-Gaussianity analysis. We find the data from two regions to be consistent with Gaussianity. In the third region, we obtain a 96.7% detection of non-Gaussianity using the wavelet test. We perform simulations to characterise the tests, and conclude that this is consistent with expected residual point source contamination. There is therefore no evidence that this detection is of cosmological origin. Our simulations show that the tests would be sensitive to any residual point sources above the data's source subtraction level of 20 mJy. The tests are also sensitive to cosmic string networks at an rms fluctuation level of $105 \mu K$ (i.e. equivalent to the best-fit observed value). They are not sensitive to string-induced fluctuations if an equal rms of Gaussian CDM fluctuations is added, thereby reducing the fluctuations due to the strings network to $74 \mu K$ rms . We especially highlight the usefulness of non-Gaussianity testing in eliminating systematic effects from our data.Comment: Minor corrections; accepted for publication to MNRA

Estimating the bispectrum of the Very Small Array data

We estimate the bispectrum of the Very Small Array data from the compact and extended configuration observations released in December 2002, and compare our results to those obtained from Gaussian simulations. There is a slight excess of large bispectrum values for two individual fields, but this does not appear when the fields are combined. Given our expected level of residual point sources, we do not expect these to be the source of the discrepancy. Using the compact configuration data, we put an upper limit of 5400 on the value of f_NL, the non-linear coupling parameter, at 95 per cent confidence. We test our bispectrum estimator using non-Gaussian simulations with a known bispectrum, and recover the input values.Comment: 17 pages, 16 figures, replaced with version accepted by MNRAS. Primordial bispectrum recalculated and figure 11 change

CMB observations from the CBI and VSA: A comparison of coincident maps and parameter estimation methods

We present coincident observations of the Cosmic Microwave Background (CMB) from the Very Small Array (VSA) and Cosmic Background Imager (CBI) telescopes. The consistency of the full datasets is tested in the map plane and the Fourier plane, prior to the usual compression of CMB data into flat bandpowers. Of the three mosaics observed by each group, two are found to be in excellent agreement. In the third mosaic, there is a 2 sigma discrepancy between the correlation of the data and the level expected from Monte Carlo simulations. This is shown to be consistent with increased phase calibration errors on VSA data during summer observations. We also consider the parameter estimation method of each group. The key difference is the use of the variance window function in place of the bandpower window function, an approximation used by the VSA group. A re-evaluation of the VSA parameter estimates, using bandpower windows, shows that the two methods yield consistent results.Comment: 10 pages, 6 figures. Final version. Accepted for publication in MNRA