Brain imaging genetics studies the genetic basis of brain structures and functions via integrating both genotypic data such as single nucleotide polymorphism (SNP) and imaging quantitative traits ...(QTs). In this area, both multi-task learning (MTL) and sparse canonical correlation analysis (SCCA) method-s are widely used since they are superior to those independent and pairwise univariate analyses. MTL methods generally incorporate a few QTs and are not designed for feature selection from a large number of QTs; while existing SCCA methods typically employ only one modality of QTs to study its association with SNPs. Both MTL and SCCA encounter computational challenges as the number of SNPs increases. In this paper, combining the merits of MTL and SCCA, we propose a novel multi-task SCCA (MTSCCA) learning framework to identify bi-multivariate associations between SNPs and multi-modal imaging QTs. MTSCCA could make use of the complementary information carried by different imaging modalities. Using the G_{2,1}-norm regularization, MTSCCA treats all SNPs in the same group together to enforce sparsity at the group level. The \ell _{2,1}-norm penalty is used to jointly select features across multiple tasks for SNPs, and across multiple modalities for QTs. A fast optimization algorithm is proposed using the grouping information of SNPs. Compared with conventional SCCA methods, MTSCCA obtains improved performance regarding both correlation coefficients and canonical weights patterns. In addition, our method runs very fast and is easy-to-implement, and thus could provide a powerful tool for genome-wide brain-wide imaging genetic studies.
Lynx is a concept under study for prioritization in the 2020 Astrophysics Decadal Survey. Providing orders of magnitude increase in sensitivity over Chandra, Lynx will examine the first black holes ...and their galaxies, map the large-scale structure and galactic halos, and shed new light on the environments of young stars and their planetary systems. In order to meet the Lynx science goals, the telescope consists of a high-angular resolution optical assembly complemented by an instrument suite that may include a High Definition X-ray Imager, X-ray Microcalorimeter and an X-ray Grating Spectrometer. The telescope is integrated onto the spacecraft to form a comprehensive observatory concept. Progress on the formulation of the Lynx telescope and observatory configuration is reported in this paper.
The research that has been conducted in the Space Geodesy Branch at NASA/Goddard Space Flight Center in preparation for meeting the 13-cm radial orbit accuracy requirement for the TOPEX/Poseidon ...(T/P) mission is described. New developments in modeling the Earth's gravitational field and modeling the complex nonconservative forces acting on T/P are highlighted. The T/P error budget is reviewed, and a prelaunch assessment of the predicted orbit determination accuracies is summarized.< >
We present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright (\(V\sim 11.1\)) Sun-like G2V star TYC 7518-468-1. The planet has an orbital ...period of \(P = 1.3866529 \pm 0.0000027 \) days, a radius of \(R_{P} = 1.285_{-0.071}^{+0.12}~R_{J}\), and a relatively large mass of \(M_{P} = 3.47_{-0.14}^{+0.15}~ M_{J}\). The star has \(R_{\star} = 1.099_{-0.046}^{+0.079}~ R_{\odot}\), \(M_{\star} = 1.092_{-0.041}^{+0.045}~ M_{\odot}\), \({T_{\rm eff}\,} = 5767_{-49}^{+50}~\) K, \({\log{g_\star}} = 4.393_{-0.060}^{+0.039}~\) (cgs), and m/H = \(+0.259_{-0.083}^{+0.085}~\), and thus, other than its slightly super-solar metallicity, appears to be a near solar twin. Surprisingly, KELT-22A exhibits kinematics and a Galactic orbit that are somewhat atypical for thin disk stars. Nevertheless, the star is rotating quite rapidly for its estimated age, shows evidence of chromospheric activity, and is somewhat metal rich. Imaging reveals a slightly fainter companion to KELT-22A that is likely bound, with a projected separation of 6\arcsec (\(\sim\)1400 AU). In addition to the orbital motion caused by the transiting planet, we detect a possible linear trend in the radial velocity of KELT-22A suggesting the presence of another relatively nearby body that is perhaps non-stellar. KELT-22Ab is highly irradiated (as a consequence of the small semi-major axis of \(a/R_{\star} = 4.97\)), and is mildly inflated. At such small separations, tidal forces become significant. The configuration of this system is optimal for measuring the rate of tidal dissipation within the host star. Our models predict that, due to tidal forces, the semi-major axis of KELT-22Ab is decreasing rapidly, and is thus predicted to spiral into the star within the next Gyr.
In the present report we clarify the role of PPARgamma in differentiation and function of human-derived monocyte/macrophages in vitro. Rosiglitazone, a selective PPARgamma activator, had no effect on ...the kinetics of appearance of monocyte/macrophage differentiation markers or on cell size or granularity. Depletion of PPARgamma by more than 90% using antisense oligonucleotides did not influence accumulation of oxidized LDL or prevent the upregulation of CD36 that normally accompanies oxLDL treatment. In contrast, PPARgamma depletion reduced the expression of ABCA1 and LXRalpha mRNAs. Metalloproteinase-9 expression, a marker of atherosclerotic plaque vulnerability, was suppressed by rosiglitazone. We conclude that activation of PPARgamma does not affect monocyte/macrophage differentiation. In addition, PPARgamma is not absolutely required for oxLDL-driven lipid accumulation, but is required for full expression of ABCA1 and LXRalpha. Our data support a role for rosiglitazone as a potential directly acting antiatherosclerotic agent.
We present a new lens model for the \(z=0.396\) galaxy cluster MACS J0416.1\(-\)2403 based on a previously known set of 77 spectroscopically confirmed, multiply imaged galaxies plus an additional set ...of 42 candidate multiply imaged galaxies from past HST and new JWST data. The new galaxies lack spectroscopic redshifts but have geometric and/or photometric redshift estimates that are presented here. The new model predicts magnifications and time delays for all multiple images. The full set of constraints totals 343, constituting the largest sample of multiple images lensed by a single cluster to date. Caustic-crossing galaxies lensed by this cluster are especially interesting. Some of these galaxies show transient events, most of which are interpreted as micro-lensing of stars at cosmological distances. These caustic-crossing arcs are expected to show similar events in future, deeper JWST observations. We provide time delay and magnification models for all these arcs. The time delays and the magnifications for different arcs are generally anti-correlated, as expected from \(N\)-body simulations. In the major sub-halos of the cluster, the dark-matter mass from our lens model correlates well with the observed number of globular clusters. This confirms earlier results, derived at lower redshifts, which suggest that globular clusters can be used as powerful mass proxies for the halo masses when lensing constraints are scarce or not available.
Current methods of studying angiogenesis are limited in their ability to serially evaluate in vivo function throughout a target tissue. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) ...and pharmacokinetic modeling provide a useful method for evaluating tissue vasculature based on contrast accumulation and washout. While it is often assumed that areas of high contrast enhancement and washout comprise areas of increased angiogenesis and tumor activity, the actual molecular pathways that are active in such areas are poorly understood. Using DCE-MRI in a murine subcutaneous tumor model, we were able to perform pharmacokinetic functional analysis of a tumor, coregistration of MRI images with histological cross-sections, immunohistochemistry, laser capture microdissection, and genetic profiling of tumor heterogeneity based on pharmacokinetic parameters. Using imaging as a template for biologic investigation, we have not found evidence of increased expression of proangiogenic modulators at the transcriptional level in either distinct pharmacokinetic region. Furthermore, these regions show no difference on histology and CD31 immunohistochemistry. However, the expression of ribosomal proteins was greatly increased in high enhancement and washout regions, implying increased protein translation and consequent increased cellular activity. Together, these findings point to the potential importance of posttranscriptional regulation in angiogenesis and the need for the development of angiogenesis-specific contrast agents to evaluate in vivo angiogenesis at a molecular level.
Three proteins, GTPase activating protein (GAP), neurofibromatosis 1 (NF1) and the yeast inhibitory regulator of the RAS‐cAMP pathway (IRA2), have the ability to stimulate the GTPase activity of Ras ...proteins from higher animals or yeast. Previous studies indicate that certain lipids are able to inhibit this activity associated with the mammalian GAP protein. Inhibition of GAP would be expected to biologically activate Ras protein. In these studies arachidonic acid is shown also to inhibit the activity of the catalytic fragments of the other two proteins, mammalian NF1 and the yeast IRA2 proteins. In addition, phosphatidic acid (containing arachidonic and stearic acid) was inhibitory for the catalytic fragment of NF1 protein, but did not inhibit the catalytic fragments of GAP or IRA2 proteins. These observations emphasize the biochemical similarity of these proteins and provide support for the suggestion that lipids might play an important role in their biological control, and therefore also in the control of Ras activity and cellular proliferation.
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