Maximum likelihood estimation of cloud height from multi-angle satellite imagery

We develop a new estimation technique for recovering depth-of-field from multiple stereo images. Depth-of-field is estimated by determining the shift in image location resulting from different camera viewpoints. When this shift is not divisible by pixel width, the multiple stereo images can be combined to form a super-resolution image. By modeling this super-resolution image as a realization of a random field, one can view the recovery of depth as a likelihood estimation problem. We apply these modeling techniques to the recovery of cloud height from multiple viewing angles provided by the MISR instrument on the Terra Satellite. Our efforts are focused on a two layer cloud ensemble where both layers are relatively planar, the bottom layer is optically thick and textured, and the top layer is optically thin. Our results demonstrate that with relative ease, we get comparable estimates to the M2 stereo matcher which is the same algorithm used in the current MISR standard product (details can be found in [IEEE Transactions on Geoscience and Remote Sensing 40 (2002) 1547--1559]). Moreover, our techniques provide the possibility of modeling all of the MISR data in a unified way for cloud height estimation. Research is underway to extend this framework for fast, quality global estimates of cloud height.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS243 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Shrinking the Quadratic Estimator

We study a regression characterization for the quadratic estimator of weak lensing, developed by Hu and Okamoto (2001,2002), for cosmic microwave background observations. This characterization motivates a modification of the quadratic estimator by an adaptive Wiener filter which uses the robust Bayesian techniques described in Strawderman (1971) and Berger (1980). This technique requires the user to propose a fiducial model for the spectral density of the unknown lensing potential but the resulting estimator is developed to be robust to misspecification of this model. The role of the fiducial spectral density is to give the estimator superior statistical performance in a "neighborhood of the fiducial model" while controlling the statistical errors when the fiducial spectral density is drastically wrong. Our estimate also highlights some advantages provided by a Bayesian analysis of the quadratic estimator

Optimal CMB Lensing Reconstruction and Parameter Estimation with SPTpol Data

We perform the first simultaneous Bayesian parameter inference and optimal reconstruction of the gravitational lensing of the cosmic microwave background (CMB), using 100 deg$^2$ of polarization observations from the SPTpol receiver on the South Pole Telescope. These data reach noise levels as low as 5.8 $\mu$K-arcmin in polarization, which are low enough that the typically used quadratic estimator (QE) technique for analyzing CMB lensing is significantly sub-optimal. Conversely, the Bayesian procedure extracts all lensing information from the data and is optimal at any noise level. We infer the amplitude of the gravitational lensing potential to be $A_\phi\,{=}\,0.949\,{\pm}\,0.122$ using the Bayesian pipeline, consistent with our QE pipeline result, but with 17\% smaller error bars. The Bayesian analysis also provides a simple way to account for systematic uncertainties, performing a similar job as frequentist "bias hardening," and reducing the systematic uncertainty on $A_\phi$ due to polarization calibration from almost half of the statistical error to effectively zero. Finally, we jointly constrain $A_\phi$ along with $A_{\rm L}$, the amplitude of lensing-like effects on the CMB power spectra, demonstrating that the Bayesian method can be used to easily infer parameters both from an optimal lensing reconstruction and from the delensed CMB, while exactly accounting for the correlation between the two. These results demonstrate the feasibility of the Bayesian approach on real data, and pave the way for future analysis of deep CMB polarization measurements with SPT-3G, Simons Observatory, and CMB-S4, where improvements relative to the QE can reach 1.5 times tighter constraints on $A_\phi$ and 7 times lower effective lensing reconstruction noise.Comment: 27 pages, 14 figures, accompanying software package available at https://cosmicmar.com/CMBLensing.j

The Design and Integrated Performance of SPT-3G

SPT-3G is the third survey receiver operating on the South Pole Telescope dedicated to high-resolution observations of the cosmic microwave background (CMB). Sensitive measurements of the temperature and polarization anisotropies of the CMB provide a powerful dataset for constraining cosmology. Additionally, CMB surveys with arcminute-scale resolution are capable of detecting galaxy clusters, millimeter-wave bright galaxies, and a variety of transient phenomena. The SPT-3G instrument provides a significant improvement in mapping speed over its predecessors, SPT-SZ and SPTpol. The broadband optics design of the instrument achieves a 430 mm diameter image plane across observing bands of 95 GHz, 150 GHz, and 220 GHz, with 1.2 arcmin FWHM beam response at 150 GHz. In the receiver, this image plane is populated with 2690 dual-polarization, tri-chroic pixels (~16000 detectors) read out using a 68X digital frequency-domain multiplexing readout system. In 2018, SPT-3G began a multiyear survey of 1500 deg$^{2}$ of the southern sky. We summarize the unique optical, cryogenic, detector, and readout technologies employed in SPT-3G, and we report on the integrated performance of the instrument.Comment: 25 pages, 11 figures. Submitted to ApJ

G2 checkpoint abrogation and checkpoint kinase-1 targeting in the treatment of cancer

Rigorous quality control steps, termed checkpoints, tightly regulate progression through the cell cycle. DNA-damaging chemotherapy and radiation activate functional cellular checkpoints. These checkpoints can facilitate DNA repair and promote cell death in unrepaired cells. There are at least three DNA damage checkpoints – at G1/S, S, and G2/M – as well as a mitotic spindle checkpoint. Most cancer cells harbour mutations in tumour suppressors and/or oncogenes, which impair certain cell checkpoints. Inhibiting the remaining cell checkpoints – particularly after exposure of cancer cells to chemotherapy and/or radiation – allows cell death, a strategy now being employed in cancer therapeutics. With our increasing knowledge of cell cycle regulation, many compounds have been developed to inhibit specific checkpoint components, particularly at the G2/M transition. One such target is checkpoint kinase-1 (Chk1). We review here the molecular framework of the cell cycle, the rationale for targeting Chk1, the preclinical concepts related to the development of Chk1 inhibitors, and the efficacy and safety results from Chk1 inhibitors now in phase I/II trials

Constraints on Λ\LambdaCDM Extensions from the SPT-3G 2018 EEEE and TETE Power Spectra

We present constraints on extensions to the $\Lambda$CDM cosmological model from measurements of the $E$-mode polarization auto-power spectrum and the temperature-$E$-mode cross-power spectrum of the cosmic microwave background (CMB) made using 2018 SPT-3G data. The extensions considered vary the primordial helium abundance, the effective number of relativistic degrees of freedom, the sum of neutrino masses, the relativistic energy density and mass of a sterile neutrino, and the mean spatial curvature. We do not find clear evidence for any of these extensions, from either the SPT-3G 2018 dataset alone or in combination with baryon acoustic oscillation and \textit{Planck} data. None of these model extensions significantly relax the tension between Hubble-constant, $H_0$, constraints from the CMB and from distance-ladder measurements using Cepheids and supernovae. The addition of the SPT-3G 2018 data to \textit{Planck} reduces the square-root of the determinants of the parameter covariance matrices by factors of $1.3 - 2.0$ across these models, signaling a substantial reduction in the allowed parameter volume. We also explore CMB-based constraints on $H_0$ from combined SPT, \textit{Planck}, and ACT DR4 datasets. While individual experiments see some indications of different $H_0$ values between the $TT$, $TE$, and $EE$ spectra, the combined $H_0$ constraints are consistent between the three spectra. For the full combined datasets, we report $H_0 = 67.49 \pm 0.53\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$, which is the tightest constraint on $H_0$ from CMB power spectra to date and in $4.1\,\sigma$ tension with the most precise distance-ladder-based measurement of $H_0$. The SPT-3G survey is planned to continue through at least 2023, with existing maps of combined 2019 and 2020 data already having $\sim3.5\times$ lower noise than the maps used in this analysis.Comment: Submitted to PRD; 19 pages, 7 figure

Performance and characterization of the SPT-3G digital frequency-domain multiplexed readout system using an improved noise and crosstalk model

The third generation South Pole Telescope camera (SPT-3G) improves upon its predecessor (SPTpol) by an order of magnitude increase in detectors on the focal plane. The technology used to read out and control these detectors, digital frequency-domain multiplexing (DfMUX), is conceptually the same as used for SPTpol, but extended to accommodate more detectors. A nearly 5x expansion in the readout operating bandwidth has enabled the use of this large focal plane, and SPT-3G performance meets the forecasting targets relevant to its science objectives. However, the electrical dynamics of the higher-bandwidth readout differ from predictions based on models of the SPTpol system. To address this, we present an updated derivation for electrical crosstalk in higher-bandwidth DfMUX systems, and identify two previously uncharacterized contributions to readout noise. The updated crosstalk and noise models successfully describe the measured crosstalk and readout noise performance of SPT-3G, and suggest improvements to the readout system for future experiments using DfMUX, such as the LiteBIRD space telescope

A Measurement of Gravitational Lensing of the Cosmic Microwave Background Using SPT-3G 2018 Data

We present a measurement of gravitational lensing over 1500 deg$^2$ of the Southern sky using SPT-3G temperature data at 95 and 150 GHz taken in 2018. The lensing amplitude relative to a fiducial Planck 2018 $\Lambda$CDM cosmology is found to be $1.020\pm0.060$, excluding instrumental and astrophysical systematic uncertainties. We conduct extensive systematic and null tests to check the robustness of the lensing measurements, and report a minimum-variance combined lensing power spectrum over angular multipoles of $50<L<2000$, which we use to constrain cosmological models. When analyzed alone and jointly with primary cosmic microwave background (CMB) spectra within the $\Lambda$CDM model, our lensing amplitude measurements are consistent with measurements from SPT-SZ, SPTpol, ACT, and Planck. Incorporating loose priors on the baryon density and other parameters including uncertainties on a foreground bias template, we obtain a $1\sigma$ constraint on $\sigma_8 \Omega_{\rm m}^{0.25}=0.595 \pm 0.026$ using the SPT-3G 2018 lensing data alone, where $\sigma_8$ is a common measure of the amplitude of structure today and $\Omega_{\rm m}$ is the matter density parameter. Combining SPT-3G 2018 lensing measurements with baryon acoustic oscillation (BAO) data, we derive parameter constraints of $\sigma_8 = 0.810 \pm 0.033$, $S_8 \equiv \sigma_8(\Omega_{\rm m}/0.3)^{0.5}= 0.836 \pm 0.039$, and Hubble constant $H_0 =68.8^{+1.3}_{-1.6}$ km s$^{-1}$ Mpc$^{-1}$. Using CMB anisotropy and lensing measurements from SPT-3G only, we provide independent constraints on the spatial curvature of $\Omega_{K} = 0.014^{+0.023}_{-0.026}$ (95% C.L.) and the dark energy density of $\Omega_\Lambda = 0.722^{+0.031}_{-0.026}$ (68% C.L.). When combining SPT-3G lensing data with SPT-3G CMB anisotropy and BAO data, we find an upper limit on the sum of the neutrino masses of $\sum m_{\nu}< 0.30$ eV (95% C.L.)