Properties of light scalar mesons from lattice QCD

Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the spectrum and decay of scalar mesons. We are able to determine the $b_1$ - $a_0$ mass difference and this leads to the conclusion that the lightest non-singlet scalar meson ($a_0$) has a mass of 1.01(4) GeV. We determine from the lattice the coupling strength to KK and $\pi \eta$. We compute the leptonic decay constant of the lightest non-singlet scalar meson. We discuss the impact of these lattice results on the interpretation of the $a_0(980)$ state. We also discuss $K^*_0$ states.Comment: version accepted by Phys Rev

Optical scattering and microphysical properties of subvisual cirrus clouds, and climatic implications

The optical and microphysical properties of subvisual cirrus clouds are derived from ground-based polarization lidar, shortwave radiation flux, and solar corona measurements of two approximately 0.75 km deep cirrus located near the tropopause. The first cloud produced no visual manifestations under excellent viewing conditions, and the second appeared to be a persistent aircraft contrail that was generally visible except in the zenith direction. Average lidar linear depolarization ratios and volume backscatter coefficients for the two clouds were 0.19 and 0.35, and 0.6x10 to the -3 and 1.4x10 to the -3 /km sr, respectively. It is estimated that the zenith-subvisual cirrus contained ice crystals of 25 micron effective diameter at a mean concentration of 25/l and ice mass content of 0.2 mg/cu m. The threshold cloud optical thickness for visual-versus-invisible cirrus, derived from both broadband shortwave flux and 0.694 micrometer lidar data, is found to be tau sub c approx equal 0.03. Such tau values are comparable to those of 5 to 10 km deep stratospheric aerosol clouds of volcanic origin and polar stratospheric clouds, which are episodic in nature. Hence, we conclude that if these clouds are a fairly common feature of the upper troposphere, as recent SAGE satellite measurements would suggest, then the impact of natural and contrail subvisual cirrus on the planet's radiation balance may be relatively significant

High fidelity sorting of remarkably similar components via metal-mediated assembly.

Subtle differences in ligand coordination angle and rigidity lead to high fidelity sorting between individual components displaying identical coordination motifs upon metal-mediated self-assembly. Narcissistic self-sorting can be achieved between highly similar ligands that vary minimally in rigidity and internal coordination angle upon combination with Fe(ii) ions and 2-formylpyridine. Selective, sequential cage formation can be precisely controlled in a single flask from a mix of three different core ligands (and 33 total components) differing only in the hybridization of one group that is uninvolved in the metal coordination process

Resonance Raman Spectroscopy Reveals that Substrate Structure Selectively Impacts the Heme-Bound Diatomic Ligands of CYP17

An important function of steroidogenic cytochromes P450 is the transformation of cholesterol to produce androgens, estrogens, and the corticosteroids. The activities of cytochrome P450c17 (CYP17) are essential in sex hormone biosynthesis, with severe developmental defects being a consequence of deficiency or mutations. The first reaction catalyzed by this multifunctional P450 is the 17α-hydroxylation of pregnenolone (PREG) to 17α-hydroxypregnenolone (17-OH PREG) and progesterone (PROG) to 17α-hydroxyprogesterone (17-OH PROG). The hydroxylated products then either are used for production of corticoids or undergo a second CYP17 catalyzed transformation, representing the first committed step of androgen formation. While the hydroxylation reactions are catalyzed by the well-known Compound I intermediate, the lyase reaction is believed to involve nucleophilic attack of the earlier peroxo- intermediate on the C20-carbonyl. Herein, resonance Raman (rR) spectroscopy reveals that substrate structure does not impact heme structure for this set of physiologically important substrates. On the other hand, rR spectra obtained here for the ferrous CO adducts with these four substrates show that substrates do interact differently with the Fe-C-O fragment, with large differences between the spectra obtained for the samples containing 17-OH PROG and 17-OH PREG, the latter providing evidence for the presence of two Fe-C-O conformers. Collectively, these results demonstrate that individual substrates can differentially impact the disposition of a heme-bound ligand, including dioxygen, altering the reactivity patterns in such a way as to promote preferred chemical conversions, thereby avoiding the profound functional consequences of unwanted side reactions

Aqueous-Based Extrusion Fabrication of Ceramics on Demand

Aqueous-Based Extrusion Fabrication is an additive manufacturing technique that extrudes ceramic slurries of high solids loading layer by layer for part fabrication. The material reservoir in a previously developed system has been modified to allow for starting and stopping of the extrusion process on demand. Design pros and cons are examined and a comparison between two material reservoir designs is made. Tests are conducted to determine the optimal deposition parameters for starting and stopping the extrudate on demand. The collected test data is used for the development of a deposition strategy that improves material deposition consistency, including reduced material buildup at sharp corners. Example parts are fabricated using the deposition strategy and hardware design.Mechanical Engineerin

Religion, School, and Judicial Decision Making: An Empirical Perspective

We analyze various influences on judicial outcomes favoring religion in cases involving elementary and secondary schools and decided by lower federal courts. A focus on religion in the school context is warranted as the most difficult and penetrating questions about the proper relationship between Church and State have arisen with special frequency, controversy, and fervor in the often-charged atmosphere of education. Schools and the Religion Clauses collide persistently, and litigation frames many of these collisions. Also, the frequency and magnitude of these legal collisions increase as various policy initiatives increasingly seek to leverage private and religious schools in the service of education reform. Our analyses include all digested Establishment and Free Exercise Clause decisions by federal court of appeals and district court judges from 1996 through 2005 that involved elementary and secondary schools. As it relates to differences between school and other (or non-school) cases, our main finding is that both measures of judicial ideology correlate with the likelihood of a pro-religion decision. That is, Republican-appointed judges were more likely than their Democratic-appointed counterparts to reach a pro-religion decision in school cases, and ideology did not correlate with a pro-religion outcome in non-school cases. Results using common space scores as a proxy for ideology were similar. Although these results dilute the strength of the “legal model” of judicial decision making, this type of case (religion) in this particular context (schools) are particularly amenable to ideological influence

Religion, School, and Judicial Decision Making: An Empirical Perspective

We analyze various influences on judicial outcomes favoring religion in cases involving elementary and secondary schools and decided by lower federal courts. A focus on religion in the school context is warranted as the most difficult and penetrating questions about the proper relationship between Church and State have arisen with special frequency, controversy, and fervor in the often-charged atmosphere of education. Schools and the Religion Clauses collide persistently, and litigation frames many of these collisions. Also, the frequency and magnitude of these legal collisions increase as various policy initiatives increasingly seek to leverage private and religious schools in the service of education reform. Our analyses include all digested Establishment and Free Exercise Clause decisions by federal court of appeals and district court judges from 1996 through 2005 that involved elementary and secondary schools. As it relates to differences between school and other (or non-school) cases, our main finding is that both measures of judicial ideology correlate with the likelihood of a pro-religion decision. That is, Republican-appointed judges were more likely than their Democratic-appointed counterparts to reach a pro-religion decision in school cases, and ideology did not correlate with a pro-religion outcome in non-school cases. Results using common space scores as a proxy for ideology were similar. Although these results dilute the strength of the “legal model” of judicial decision making, this type of case (religion) in this particular context (schools) are particularly amenable to ideological influence