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The atmosphere of Titan, Saturn's largest moon, exhibits interesting UV- and radiation-driven chemistry between nitrogen and methane, resulting in dipolar, nitrile-containing molecules. The assembly and subsequent solvation of such molecules in the alkane lakes and seas found on the moon's surface are of particular interest for investigating the possibility of prebiotic chemistry in Titan's hydrophobic seas. Here we characterize the solvation of acetonitrile, a product of Titan's atmospheric radiation chemistry tentatively detected on Titan's surface [H. B. Niemann et al., Nature 438, 779-784 (2005)], in an alkane mixture estimated to match a postulated composition of the smaller lakes during cycles of active drying and rewetting. Molecular dynamics simulations are employed to determine the potential of mean force of acetonitrile (CH3CN) clusters moving from the alkane vapor into the bulk liquid. We find that the clusters prefer the alkane liquid to the vapor and do not dissociate in the bulk liquid. This opens up the possibility that acetonitrile-based microscopic polar chemistry may be possible in the otherwise nonpolar Titan lakes. [ABSTRACT FROM AUTHOR]

Purpose To produce and maintain a database of National Institutes of Health ( NIH) funding of the American Association of Physicists in Medicine ( AAPM) members, to perform a top-level analysis of these data, and to make these data (hereafter referred to as the AAPM research database) available for the use of the AAPM and its members. Methods NIH-funded research dating back to 1985 is available for public download through the NIH exporter website, and AAPM membership information dating back to 2002 was supplied by the AAPM. To link these two sources of data, a data mining algorithm was developed in Matlab. The false-positive rate was manually estimated based on a random sample of 100 records, and the false-negative rate was assessed by comparing against 99 member-supplied PI _ ID numbers. The AAPM research database was queried to produce an analysis of trends and demographics in research funding dating from 2002 to 2015. Results A total of 566 PI _ ID numbers were matched to AAPM members. False-positive and -negative rates were respectively 4% (95% CI: 1-10%, N = 100) and 10% (95% CI: 5-18%, N = 99). Based on analysis of the AAPM research database, in 2015 the NIH awarded $ USD 110M to members of the AAPM. The four NIH institutes which historically awarded the most funding to AAPM members were the National Cancer Institute, National Institute of Biomedical Imaging and Bioengineering, National Heart Lung and Blood Institute, and National Institute of Neurological Disorders and Stroke. In 2015, over 85% of the total NIH research funding awarded to AAPM members was via these institutes, representing 1.1% of their combined budget. In the same year, 2.0% of AAPM members received NIH funding for a total of $116M, which is lower than the historic mean of $120M (in 2015 USD). Conclusions A database of NIH-funded research awarded to AAPM members has been developed and tested using a data mining approach, and a top-level analysis of funding trends has been performed. Current funding of AAPM members is lower than the historic mean. The database will be maintained by members of the Working group for the development of a research database ( WGDRD) on an annual basis, and is available to the AAPM, its committees, working groups, and members for download through the AAPM electronic content website. A wide range of questions regarding financial and demographic funding trends can be addressed by these data. This report has been approved for publication by the AAPM Science Council. [ABSTRACT FROM AUTHOR]

To evaluate the association between enrollment into an AIDS Drug Assistance Program (ADAP) and use of highly active antiretroviral therapy (HAART) and antihypertensive therapy.Cross-sectional analyses of data were performed on HAART-eligible women enrolled in the California (n = 439), Illinois (n = 168), and New York (n = 487) Women's Interagency HIV Study sites. A subset of HIV-infected women with hypertension (n = 395) was also analyzed. Unadjusted and adjusted backward stepwise elimination logistic regression measured the association between demographic, behavioral, and health service factors and nonuse of HAART or antihypertensive medication.In adjusted analysis of HAART nonuse, women without ADAP were significantly more likely not to use HAART (odds ratio [OR], 2.4; 95% confidence interval [CI], 1.5-3.7) than women with ADAP. In adjusted analysis of antihypertensive medication nonuse, women without ADAP had an increased but not significant odds of antihypertensive medication nonuse (OR, 2.4; 95% CI, 0.93-6.0) than women with ADAP.Government-funded programs for prescription drug coverage such as ADAP may play an important role in how HIV-positive women access and use essential medications for chronic diseases. [ABSTRACT FROM AUTHOR]

The regularity of the limit function of a linear subdivision scheme is essentially irrelevant to the initial data. How data dependent, then, is the regularity of the limit of a nonlinear subdivision scheme? The answer is the most obvious—it depends. In this paper, we prove that the nonlinear convexity preserving subdivision scheme developed independently by Floater and Micchelli [M. S. Floater and C. A. Micchelli, Approximation Theory, Marcel Dekker, New York, 1998, pp. 209–224] and Kuijt and van Damme [F. Kuijt and R. van Damme, Constr. Approx., 14 (1998), pp. 609–630] exhibits a rather strong nonlinear, data-dependent, behavior: For any ν ∊ (1, 2), there exists initial convex data such that the critical Hölder regularity of the limit curve is exactly ν. We also show that the limit function of any initial data always has Hölder regularity less than 2, unless if restricted to a subset of the domain at which the initial data is sampled from the convex branch of a rational polynomial of degree 2 over degree 1. This result stands in contrast to what is reported in several recent publications on nonlinear subdivision schemes [I. Ur Rahman, I. Drori, V. C. Stodden, D. L. Donoho, and P. Schröder, SIAM J. Multiscale Modeling and Simulation, submitted, 2005; G. Xie and T. P.-Y. Yu, Constr. Approx., 22 (2005), pp. 219–254; G. Xie and T. P.-Y. Yu, Advances in Constructive Approximation, 2004, pp. 519–533; I. Daubechies, O. Runborg, and W. Sweldens, Constr. Approx., 3 (2004), pp. 399–463; T. P.-Y. Yu, Cutting corners on the sphere, preprint available at http://www.rpi.edu/∼yut/Papers/CuttingCorners.pdf, 2005], in which various families of nonlinear subdivision schemes are either proved or empirically observed to have rather weak nonlinearity in the sense that they produce limit curves with smoothness insensitive to initial data. [ABSTRACT FROM AUTHOR]

Classical swine fever virus nonstructural protein 5B (NS5B) encodes an RNA-dependent RNA polymerase, a key enzyme of the viral replication complex. To better understand the initiation of viral RNA synthesis and to establish an in vitro replication system, a recombinant NS5B protein, lacking the C-terminal 24-amino acid hydrophobic domain, was expressed in Escherichia coli. The truncated fusion protein (NS5BΔ24) was purified on a Ni-chelating HisTrap affinity column and demonstrated to initiate either plus- or minus-strand viral RNA synthesis de novo in a primer-independent manner but not by terminal nucleotidyle transferase activity. De novo RNA synthesis represented the preferred mechanism for initiation of classical swine fever virus RNA synthesis by RNA-dependent RNA polymerase in vitro. Both Mg2+ and Mn2+ supported de novo initiation, however, RNA synthesis was more efficient in the presence of Mn2+ than in the presence of Mg2+. De novo initiation of RNA synthesis was stimulated by preincubation with 0.5 m m GTP, and a 3′-terminal cytidylate on the viral RNA template was preferred for de novo initiation. Furthermore, the purified protein was also shown, by North-Western blot analysis, to specifically interact with the 3′-end of both plus- and minus-strand viral RNA templates. [ABSTRACT FROM AUTHOR]

Discrete time crystals are novel phases of matter that break the discrete time translational symmetry of a periodically driven system. In this Letter, we propose a classical system of weakly nonlinear parametrically driven coupled oscillators as a test bed to understand these phases. Such a system of parametric oscillators can be used to model period-doubling instabilities of Josephson junction arrays as well as semiconductor lasers. To show that this instability leads to a discrete time crystal we first show that a certain limit of the system is close to Langevin dynamics in a symmetry breaking potential. We numerically show that this phase exists even in the presence of Ising symmetry breaking using a Glauber dynamics approximation. We then use a field theoretic argument to show that these results are robust to other approximations including the semiclassical limit when applied to dissipative quantum systems.