Inhibition of Fructose-1,6-bisphosphatase by Aminoimidazole Carboxamide Ribotide Prevents Growth of Salmonella enterica purH Mutants on Glycerol

The enzyme fructose-1,6-bisphosphatase (FBP) is key regulatory point in gluconeogenesis. Mutants of Salmonella enterica lacking purH accumulate 5-amino-4-imidazole carboxamide ribotide (AICAR) and are unable to utilize glycerol as sole carbon and energy sources. The work described here demonstrates this lack of growth is due to inhibition of FBP by AICAR. Mutant alleles of fbp that restore growth on glycerol encode proteins resistant to inhibition by AICAR and the allosteric regulator AMP. This is the first report of biochemical characterization of substitutions causing AMP resistance in a bacterial FBP. Inhibition of FBP activity by AICAR occurs at physiologically relevant concentrations and may represent a form of regulation of gluconeogenic flux in Salmonella enterica

Monotone Subsequences in the Sequence of Fractional Parts of Multiples of an Irrational

Hammersley [7] showed that if X1, X2, . . . is a sequence of independent identically distributed random variables whose common distribution is continuous, and if ln+(ln-) denotes the length of the longest increasing (decreasing) subsequence of X1, X2, . . ., Xn, then there is a constant c such that ln-⁄n½→ c and ln+⁄n½→ c in probability, as n → ∞. Kesten [8] showed that in fact there is almost sure convergence. Logan and Shepp [11] proved that c ≧ 2, and recently Versik and Kerov [13] have announced that c = 2

Geometric limits of Mandelbrot and Julia sets under degree growth

First, for the family P_{n,c}(z) = z^n + c, we show that the geometric limit of the Mandelbrot sets M_n(P) as n tends to infinity exists and is the closed unit disk, and that the geometric limit of the Julia sets J(P_{n,c}) as n tends to infinity is the unit circle, at least when the modulus of c is not one. Then we establish similar results for some generalizations of this family; namely, the maps F_{t,c} (z) = z^t+c for real t>= 2, and the rational maps R_{n,c,a} (z) = z^n + c + a/z^n.Comment: 29 pages, 16 figures (34 pic files), submitte

The Effects of Trial Judge Gender and Public Opinion on Criminal Sentencing Decisions

We explore the effects of a trial judge\u27s gender in criminal sentencing decisions by addressing two unsettled questions. First, do female and male trial judges sentence criminal offenders differently from one another? While numerous qualitative and quantitative scholars have examined this question, the results lack consistency. Second, are female trial judges\u27 sentencing practices differentially affected by public opinion compared to male judges\u27 behavior? Little research exists on this second question, but existing theory on how females and males make decisions and operate as judges is informative. To provide new empirical insight into these questions, we rely on two sources of data: judge sentences stemming from Colorado trial court marijuana-related drug cases filed from 2004 to 2009 and local public opinion on marijuana from a 2006 Colorado general election initiative on whether to legalize marijuana possession. These data permit us to analyze judges\u27 baseline sentencing practices (pre-2006 initiative) and the effect that public opinion has on the sentences (pre- vs. post-2006 initiative). The statistical modeling indicates that while male and female judges in Colorado generally do not sentence defendants differently from one another, there is one exception. Namely, female judges are more lenient than male judges when sentencing female defendants. Our empirical results also indicate that while Colorado trial judges were responsive to local public opinion following the 2006 marijuana initiative, that responsiveness was not more potent for female judges than it was for male judges. Together, these empirical results provide important new insights into the behavior of male and female trial court judges

Lower Bounds for Nonparametric Density Estimation Rates

In Wegman\u27s paper [5] on nonparametric density estimation, he states that it would be interesting to show that there is no density estimator which has mean integrated square rate better than O(n-1). The object of this note is to prove such a result, making no arbitrary assumptions about the specific form of the estimator. This proof is given in Section 2. Our method applies to some other measures of error, as we point out in Section 3

Blasius boundary layer solution with slip flow conditions

As the number of applications of micro electro mechanical systems, or MEMS, increase, the variety of flow geometries that must be analyzed at the micro-scale is also increasing. To date, most of the work on MEMS scale fluid mechanics has focused on internal flow geometries, such as microchannels. As applications such as micro-scale flyers are considered, it is becoming necessary to consider external flow geometries. Adding a slip-flow condition to the Blasius boundary layer allows these flows to be studied without extensive computation. © 2001 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87372/2/518_1.pd

Testing the Accuracy and Stability of Spectral Methods in Numerical Relativity

The accuracy and stability of the Caltech-Cornell pseudospectral code is evaluated using the KST representation of the Einstein evolution equations. The basic "Mexico City Tests" widely adopted by the numerical relativity community are adapted here for codes based on spectral methods. Exponential convergence of the spectral code is established, apparently limited only by numerical roundoff error. A general expression for the growth of errors due to finite machine precision is derived, and it is shown that this limit is achieved here for the linear plane-wave test. All of these tests are found to be stable, except for simulations of high amplitude gauge waves with nontrivial shift.Comment: Final version, as published in Phys. Rev. D; 13 pages, 16 figure

A Resource-Free Evaluation Metric for Cross-Lingual Word Embeddings Based on Graph Modularity

Cross-lingual word embeddings encode the meaning of words from different languages into a shared low-dimensional space. An important requirement for many downstream tasks is that word similarity should be independent of language - i.e., word vectors within one language should not be more similar to each other than to words in another language. We measure this characteristic using modularity, a network measurement that measures the strength of clusters in a graph. Modularity has a moderate to strong correlation with three downstream tasks, even though modularity is based only on the structure of embeddings and does not require any external resources. We show through experiments that modularity can serve as an intrinsic validation metric to improve unsupervised cross-lingual word embeddings, particularly on distant language pairs in low-resource settings.Comment: Accepted to ACL 2019, camera-read