The inhibitory rod cGMP phosphodiesterase gamma subunit (PDEgamma) is a major component of the photoresponse and is required to support rod integrity. Pdeg(tm1)/Pdeg(tm1) mice (which lack PDEgamma ...owing to a targeted disruption of the Pdeg gene) suffer from a very rapid and severe photoreceptor degeneration. The Y84G (Tyr(84)-->Gly) allele of PDEgamma has previously been shown in experiments carried out in vitro to reduce the regulatory control of the PDE catalytic core (PDEalphabeta) exerted by the wild-type gamma subunit. To determine the effects of this mutation on in vivo function, the murine opsin promoter was used to direct expression to the photoreceptors of +/Pdeg(tm1) mice of a mutant Y84G and a wild-type PDEgamma control transgene. The transgenic mice were crossed with Pdeg(tm1)/Pdeg(tm1) mice to generate animals able to synthesize only the transgenic PDEgamma. Our results showed that wild-type PDEgamma and Y84G transgenes could complement the Pdeg(tm1)/Pdeg(tm1) mutant for photoreceptor survival. The mutation caused a significant biochemical defect in PDE activation by transducin. However, the Y84G mutation did not fully eliminate the control of PDEgamma on the PDE catalytic core in vivo; the expression of the mutant subunit was associated with only a 10-fold reduction in the amplitude of the a-wave and a 1.5-fold decrease in the b-wave of the corneal electroretinogram. Unexpectedly, the mutation caused a much 'milder' phenotype in vivo than was predicted from the biochemical assays in vitro.
A heterogeneous sample of 61 chronically psychotic patients were subgrouped according to the presence or absence of a self-reported history of childhood abuse. Patients reporting childhood abuse (n = ...27) had an earlier age of onset, scored higher on the Dissociative Experiences Scale, reported more amnesia, and relapsed more frequently than patients not reporting abuse histories. Histories of childhood abuse and of past stimulant abuse predicted the score on the Dissociative Experiences Scale. A history of childhood abuse may thus contribute to the symptomatology and course of illness in some chronically psychotic patients.
The recent R/V Maurice Ewing EW9105 Hydrosweep survey of the East Pacific Rise (EPR) and adjacent flanks between 7°S and 9°S provides an excellent opportunity to explore the causal relationship ...between the ridge and the abyssal hills which form on its flanks. These data cover 100% of the flanking abyssal hills to 115 km on either side of the axis. We apply the methodology of Goff and Jordan (1988) for estimating statistical characteristics of abyssal hill morphology (rms height, characteristic lengths and widths, plan view aspect ratio, azimuthal orientation, and fractal dimension). Principal observations include the following: (1) the rms height of abyssal hill morphology is negatively correlated with the width of the 5‐ to 20‐km‐wide crestal high, consistent with the observations of Goff (1991) for northern EPR abyssal hill morphology; (2) the characteristic abyssal hill width displays no systematic variation with position relative to ridge segmentation within the EW9105 survey area, in contrast with observations of Goff (1991) for northern EPR abyssal hill morphology in which characteristic widths tend to be smallest at segment ends and largest toward the middle of segments; (3) abyssal hill rms heights and characteristic widths are very large just north of a counterclockwise rotating “nannoplate”, suggesting that the overlap region is being pushed northward in response to microplate‐style tectonics; and (4) within the 7°12′S–8°38′S segment, abyssal hill lineaments are generally parallel to the ridge axis, while south of this area, abyssal hill lineaments rotate with a larger “radius of curvature” than does the EPR axis approaching the EPR‐Wilkes ridge‐transform intersection.
The inhibitory rod cGMP phosphodiesterase γ subunit (PDEγ) is a major component of the photoresponse and is required to support rod integrity. Pdegtm1/Pdegtm1 mice (which lack PDEγ owing to a ...targeted disruption of the Pdeg gene) suffer from a very rapid and severe photoreceptor degeneration. The Y84G (Tyr84 → Gly) allele of PDEγ has previously been shown in experiments carried out in vitro to reduce the regulatory control of the PDE catalytic core (PDEαβ) exerted by the wild-type γ subunit. To determine the effects of this mutation on in vivo function, the murine opsin promoter was used to direct expression to the photoreceptors of +/Pdegtm1 mice of a mutant Y84G and a wild-type PDEγ control transgene. The transgenic mice were crossed with Pdegtm1/Pdegtm1 mice to generate animals able to synthesize only the transgenic PDEγ. Our results showed that wild-type PDEγ and Y84G transgenes could complement the Pdegtm1/Pdegtm1 mutant for photoreceptor survival. The mutation caused a significant biochemical defect in PDE activation by transducin. However, the Y84G mutation did not fully eliminate the control of PDEγ on the PDE catalytic core in vivo; the expression of the mutant subunit was associated with only a 10-fold reduction in the amplitude of the a-wave and a 1.5-fold decrease in the b-wave of the corneal electroretinogram. Unexpectedly, the mutation caused a much ‘milder’ phenotype in vivo than was predicted from the biochemical assays in vitro.
We present measurements of the Baryon Acoustic Oscillation (BAO) scale in redshift-space using the clustering of quasars. We consider a sample of 147,000 quasars from the extended Baryon Oscillation ...Spectroscopic Survey (eBOSS) distributed over 2044 square degrees with redshifts \(0.8 < z < 2.2\) and measure their spherically-averaged clustering in both configuration and Fourier space. Our observational dataset and the 1400 simulated realizations of the dataset allow us to detect a preference for BAO that is greater than 2.8\(\sigma\). We determine the spherically averaged BAO distance to \(z = 1.52\) to 3.8 per cent precision: \(D_V(z=1.52)=3843\pm147 \left(r_{\rm d}/r_{\rm d, fid}\right)\ \)Mpc. This is the first time the location of the BAO feature has been measured between redshifts 1 and 2. Our result is fully consistent with the prediction obtained by extrapolating the Planck flat \(\Lambda\)CDM best-fit cosmology. All of our results are consistent with basic large-scale structure (LSS) theory, confirming quasars to be a reliable tracer of LSS, and provide a starting point for numerous cosmological tests to be performed with eBOSS quasar samples. We combine our result with previous, independent, BAO distance measurements to construct an updated BAO distance-ladder. Using these BAO data alone and marginalizing over the length of the standard ruler, we find \(\Omega_{\Lambda} > 0\) at 6.6\(\sigma\) significance when testing a \(\Lambda\)CDM model with free curvature.
A&A 608, A130 (2017) We present a measurement of baryon acoustic oscillations (BAO) in the
cross-correlation of quasars with the Ly$\alpha$-forest flux-transmission at a
mean redshift $z=2.40$. The ...measurement uses the complete SDSS-III data sample:
168,889 forests and 234,367 quasars from the SDSS Data Release DR12. In
addition to the statistical improvement on our previous study using DR11, we
have implemented numerous improvements at the analysis level allowing a more
accurate measurement of this cross-correlation. We also developed the first
simulations of the cross-correlation allowing us to test different aspects of
our data analysis and to search for potential systematic errors in the
determination of the BAO peak position. We measure the two ratios
$D_{H}(z=2.40)/r_{d} = 9.01 \pm 0.36$ and $D_{M}(z=2.40)/r_{d} = 35.7 \pm 1.7$,
where the errors include marginalization over the non-linear velocity of
quasars and the metal - quasar cross-correlation contribution, among other
effects. These results are within $1.8\sigma$ of the prediction of the
flat-$\Lambda$CDM model describing the observed CMB anisotropies. We combine
this study with the Ly$\alpha$-forest auto-correlation function
2017A&A...603A..12B, yielding $D_{H}(z=2.40)/r_{d} = 8.94 \pm 0.22$ and
$D_{M}(z=2.40)/r_{d} = 36.6 \pm 1.2$, within $2.3\sigma$ of the same
flat-$\Lambda$CDM model.
A&A 603, A12 (2017) We use flux-transmission correlations in \Lya forests to measure the imprint
of baryon acoustic oscillations (BAO). The study uses spectra of 157,783
quasars in the redshift range ...$2.1\le z \le 3.5$ from the Sloan Digital Sky
Survey (SDSS) Data Release 12 (DR12). Besides the statistical improvements on
our previous studies using SDSS DR9 and DR11, we have implemented numerous
improvements in the analysis procedure, allowing us to construct a physical
model of the correlation function and to investigate potential systematic
errors in the determination of the BAO peak position. The Hubble distance,
$\DHub=c/H(z)$, relative to the sound horizon is $\DHub(z=2.33)/r_d=9.07 \pm
0.31$. The best-determined combination of comoving angular-diameter distance,
$\DM$, and the Hubble distance is found to be
$\DHub^{0.7}\DM^{0.3}/r_d=13.94\pm0.35$. This value is $1.028\pm0.026$ times
the prediction of the flat-\lcdm model consistent with the cosmic microwave
background (CMB) anisotropy spectrum. The errors include marginalization over
the effects of unidentified high-density absorption systems and fluctuations in
ultraviolet ionizing radiation. Independently of the CMB measurements, the
combination of our results and other BAO observations determine the open-\lcdm
density parameters to be $\om=0.296 \pm 0.029$, $\ol=0.699 \pm 0.100$ and
$\Omega_k = -0.002 \pm 0.119$.
We report a detection of the baryon acoustic oscillation (BAO) feature in the flux-correlation function of the Ly{\alpha} forest of high-redshift quasars with a statistical significance of five ...standard deviations. The study uses 137,562 quasars in the redshift range \(2.1\le z \le 3.5\) from the Data Release 11 (DR11) of the Baryon Oscillation Spectroscopic Survey (BOSS) of SDSS-III. This sample contains three times the number of quasars used in previous studies. The measured position of the BAO peak determines the angular distance, \(D_A(z=2.34)\) and expansion rate, \(H(z=2.34)\), both on a scale set by the sound horizon at the drag epoch, \(r_d\). We find \(D_A/r_d=11.28\pm0.65(1\sigma)^{+2.8}_{-1.2}(2\sigma)\) and \(D_H/r_d=9.18\pm0.28(1\sigma)\pm0.6(2\sigma)\) where \(D_H=c/H\). The optimal combination, \(\sim D_H^{0.7}D_A^{0.3}/r_d\) is determined with a precision of \(\sim2\%\). For the value \(r_d=147.4~{\rm Mpc}\), consistent with the CMB power spectrum measured by Planck, we find \(D_A(z=2.34)=1662\pm96(1\sigma)~{\rm Mpc}\) and \(H(z=2.34)=222\pm7(1\sigma)~{\rm km\,s^{-1}Mpc^{-1}}\). Tests with mock catalogs and variations of our analysis procedure have revealed no systematic uncertainties comparable to our statistical errors. Our results agree with the previously reported BAO measurement at the same redshift using the quasar-Ly{\alpha} forest cross-correlation. The auto-correlation and cross-correlation approaches are complementary because of the quite different impact of redshift-space distortion on the two measurements. The combined constraints from the two correlation functions imply values of \(D_A/r_d\) and \(D_H/r_d\) that are, respectively, 7% low and 7% high compared to the predictions of a flat \(\Lambda\)CDM cosmological model with the best-fit Planck parameters. With our estimated statistical errors, the significance of this discrepancy is \(\approx 2.5\sigma\).
The Lyman-\(\beta\) forest refers to a region in the spectra of distant quasars that lies between the rest-frame Lyman-\(\beta\) and Lyman-\(\gamma\) emissions. The forest in this region is dominated ...by a combination of absorption due to resonant Ly\(\alpha\) and Ly\(\beta\) scattering. When considering the 1D Ly\(\beta\) forest in addition to the 1D Ly\(\alpha\) forest, the full statistical description of the data requires four 1D power spectra: Ly\(\alpha\) and Ly\(\beta\) auto-power spectra and the Ly\(\alpha\)-Ly\(\beta\) real and imaginary cross-power spectra. We describe how these can be measured using an optimal quadratic estimator that naturally disentangles Ly\(\alpha\) and Ly\(\beta\) contributions. Using a sample of approximately 60,000 quasar sight-lines from the BOSS Data Release 9, we make the measurement of the one-dimensional power spectrum of fluctuations due to the Ly\(\beta\) resonant scattering. While we have not corrected our measurements for resolution damping of the power and other systematic effects carefully enough to use them for cosmological constraints, we can robustly conclude the following: i) Ly\(\beta\) power spectrum and Ly\(\alpha\)-Ly\(\beta\) cross spectra are detected with high statistical significance; ii) the cross-correlation coefficient is \(\approx 1\) on large scales; iii) the Ly\(\beta\) measurements are contaminated by the associated OVI absorption, which is analogous to the SiIII contamination of the Ly\(\alpha\) forest. Measurements of the Ly\(\beta\) forest will allow extension of the usable path-length for the Ly\(\alpha\) measurements while allowing a better understanding of the physics of intergalactic medium and thus more robust cosmological constraints.
PDF
