SPIDER - V. Measuring Systematic Effects in Early-Type Galaxy Stellar Masses from Photometric SED Fitting

We present robust statistical estimates of the accuracy of early-type galaxy stellar masses derived from spectral energy distribution (SED) fitting as functions of various empirical and theoretical assumptions. Using large samples consisting of 40,000 galaxies from the Sloan Digital Sky Survey, of which 5,000 are also in the UKIRT Infrared Deep Sky Survey, with spectroscopic redshifts in the range 0.05 \leq z \leq 0.095, we test the reliability of some commonly used stellar population models and extinction laws for computing stellar masses. Spectroscopic ages (t), metallicities (Z), and extinctions (A) are also computed from fits to SDSS spectra using various population models. These constraints are used in additional tests to estimate the systematic errors in the stellar masses derived from SED fitting, where t, Z, and A are typically left as free parameters. We find reasonable agreement in mass estimates among stellar population models, with variation of the IMF and extinction law yielding systematic biases on the mass of nearly a factor of 2, in agreement with other studies. Removing the near-infrared bands changes the statistical bias in mass by only 0.06 dex, adding uncertainties of 0.1 dex at the 95% CL. In contrast, we find that removing an ultraviolet band is more critical, introducing 2{\sigma} uncertainties of 0.15 dex. Finally, we find that stellar masses are less affected by absence of metallicity and/or dust extinction knowledge. However, there is a definite systematic offset in the mass estimate when the stellar population age is unknown, up to a factor of 2.5 for very old (12 Gyr) stellar populations. We present the stellar masses for our sample, corrected for the measured systematic biases due to photometrically determined ages, finding that age errors produce lower stellar masses by 0.15 dex, with errors of 0.02 dex at the 95% CL for the median stellar age subsample.Comment: Accepted for Publication in the Astronomical Journa

Swedish Trends in Criminal Assaults against Minors since Banning Spanking, 1981-2010

Abstract: This study uses Swedish trends in alleged criminal assaults against minors to investigate whether societal violence has decreased since their spanking ban in 1979.The rates of all assaults increased dramatically. Compared to 1981, criminal statistics in 2010 included about 22 times as many cases of physical child abuse, 24 times as many assaults by minors against minors, and 73 times as many rapes of minors under the age of 15. Although the first cohort born after the spanking ban showed a smaller percentage increase in perpetrating assaults against minors than other age cohorts, those born since the spanking ban had almost a 12-fold increase in perpetrations altogether, compared to a 7-fold increase for older age cohorts. Although some increases might reflect changes in reporting practices, their magnitude and consistency suggest that part of these increases are real. Recent increases may be due to expanding proscriptions against nonphysical disciplinary consequences. Future research needs to identify effective alternative disciplinary consequences to replace spanking. Otherwise, proscriptions against an expanding range of disciplinary consequences may undermine the kind of appropriate parental authority that can facilitate the development of impulse control in oppositional children and appropriate respect for others, especially the physically vulnerable

The Taxation of E-Commerce: Transcript from the 1999 Judge James R. Browning Symposium

The Taxation of E-Commerc

The Taxation of E-Commerce: Transcript from the 1999 Judge James R. Browning Symposium

The Taxation of E-Commerc

Adenovirus-mediated transfer of a gene encoding acyloxyacyl hydrolase (AOAH) into mice increases tissue and plasma AOAH activity

Although the host response to gram-negative bacterial infection follows largely from the interactions of bacterial lipopolysaccharides (LPS or endotoxin) with host cells, little information is available concerning the mechanisms by which the host eliminates or detoxifies LPS. Acyloxyacyl hydrolase (AOAH) is an enzyme, found in phagocytic cells, that catalyzes the enzymatic deacylation of the lipid A moiety of LPS. Enzymatically deacylated LPS is much less potent than LPS at inducing responses in human cells, and it can antagonize the ability of LPS to activate human macrophages, neutrophils, and endothelial cells. Despite these observations, the physiologic role of LPS deacylation remains undefined. To investigate the ability of AOAH to carry out LPS deacylation in vivo, we produced a recombinant adenovirus carrying a gene encoding AOAH (Ad.CMV-AOAH) and employed this vector to elicit transient overexpression of AOAH in mice. Mice infected with Ad.CMV-AOAH expressed high levels of the enzyme in plasma, liver, spleen, and kidney. Although adenovirus-induced hepatitis reduced hepatic uptake of intravenously injected [H-3]LPS, animals expressing the transgene deacylated a larger fraction of the [3H]LPS taken up by their livers than did mice infected with a control adenovirus. These studies indicate that AOAH can catalyze the deacylation of LPS in vivo, and they provide evidence that the rates of hepatic LPS uptake and deacylation are not closely linked