Periodic Optical Variability of Radio Detected Ultracool Dwarfs

A fraction of very low mass stars and brown dwarfs are known to be radio active, in some cases producing periodic pulses. Extensive studies of two such objects have also revealed optical periodic variability and the nature of this variability remains unclear. Here we report on multi-epoch optical photometric monitoring of six radio detected dwarfs, spanning the $\sim$M8 - L3.5 spectral range, conducted to investigate the ubiquity of periodic optical variability in radio detected ultracool dwarfs. This survey is the most sensitive ground-based study carried out to date in search of periodic optical variability from late-type dwarfs, where we obtained 250 hours of monitoring, delivering photometric precision as low as $\sim$0.15%. Five of the six targets exhibit clear periodicity, in all cases likely associated with the rotation period of the dwarf, with a marginal detection found for the sixth. Our data points to a likely association between radio and optical periodic variability in late-M/early-L dwarfs, although the underlying physical cause of this correlation remains unclear. In one case, we have multiple epochs of monitoring of the archetype of pulsing radio dwarfs, the M9 TVLM 513-46546, spanning a period of 5 years, which is sufficiently stable in phase to allow us to establish a period of 1.95958 $\pm$ 0.00005 hours. This phase stability may be associated with a large-scale stable magnetic field, further strengthening the correlation between radio activity and periodic optical variability. Finally, we find a tentative spin-orbit alignment of one component of the very low mass binary LP 349-25.Comment: Accepted to The Astrophysical Journal; 22 pages; 12 figure

Inversion in the In0.53Ga0.47As metal-oxide-semiconductor system: Impact of the In0.53Ga0.47As doping concentration

In0.53Ga0.47As metal-oxide-semiconductor (MOS) capacitors with an Al2O3 gate oxide and a range of n and p-type In0.53Ga0.47As epitaxial concentrations were examined. Multi-frequency capacitance-voltage and conductance-voltage characterization exhibited minority carrier responses consistent with surface inversion. The measured minimum capacitance at high frequency (1 MHz) was in excellent agreement with the theoretical minimum capacitance calculated assuming an inverted surface. Minority carrier generation lifetimes, sg, extracted from experimentally measured transition frequencies, xm, using physics based a.c. simulations, demonstrated a reduction in sg with increasing epitaxial doping concentration. The frequency scaled conductance, G/x, in strong inversion allowed the estimation of accurate Cox values for these MOS devices

Courts Caught in the Web: Fixing a Failed System with Factors Designed for Sentencing Child Pornography Offenders

This Article introduces a Study, compiling data of 238 internet crimes against children occurring between 2008-2012, and concludes there is no correlation between presentence risk assessment scores and the subsequent sentences imposed by Northeast Ohio judges. The current risk assessment tools are insufficient and should be replaced by a comprehensive multi-factor approach that assesses relevant factors and identifies an offender’s placement on the “Spiral of Abuse” to aid Northeast Ohio judges in crafting fair, just, and consistent sentences for CPOs

Courts Caught in the Web: Fixing a Failed System with Factors Designed for Sentencing Child Pornography Offenders

This Article introduces a Study, compiling data of 238 internet crimes against children occurring between 2008-2012, and concludes there is no correlation between presentence risk assessment scores and the subsequent sentences imposed by Northeast Ohio judges. The current risk assessment tools are insufficient and should be replaced by a comprehensive multi-factor approach that assesses relevant factors and identifies an offender’s placement on the “Spiral of Abuse” to aid Northeast Ohio judges in crafting fair, just, and consistent sentences for CPOs

Solvent and thermal stability, and pH kinetics, of proline-specific dipeptidyl peptidase IV-like enzyme from bovine serum

Proline-specific dipeptidyl peptidase-like (DPP IV; EC 3.4.14.5) activity in bovine serum has attracted little attention despite its ready availability and the paucity of useful proline-cleaving enzymes. Bovine serum DPP IV-like peptidase is very tolerant of organic solvents, particularly acetonitrile: upon incubation for 1 h at room temperature in 70% acetonitrile, 47% dimethylformamide, 54% DMSO and 33% tetrahydrofuran (v/v concentrations) followed by dilution into the standard assay mixture, the enzyme retained half of its aqueous activity. As for thermal performance in aqueous buffer, its relative activity increased up to 50 ◦C. Upon thermoinactivation at 71 ◦C, pH 8.0 (samples removed periodically, cooled on ice, then assayed under optimal conditions), residual activities over short times fit a first-order decay with a k-value of 0.071±0.0034 min−1. Over longer times, residual activities fit to a double exponential decay with k1 and k2 values of 0.218±0.025 min−1 (46±4% of overall decay) and 0.040±0.002 min−1 (54±4% of overall decay), respectively. The enzyme’s solvent and thermal tolerances suggest that it may have potential for use as a biocatalyst in industry. Kinetic analysis with the fluorogenic substrate Gly-Pro-7-aminomethylcoumarin over a range of pH values indicated two pK values at 6.18±0.07 and at 9.70±0.50. We ascribe the lower value to the active site histidine; the higher may be due to the active site serine or to a free amino group in the substrate

The Concept of Trust and the Political Economy of John Maynard Keynes, Illustrated Using Central Bank Forward Guidance and the Democratic Dilemma in Europe

Trust is an issue to which Keynesians and post-Keynesians have paid relatively little attention. However, properly understood it is an aspect of almost all activity, including key elements of socio-economic reality. Without trust, market exchange is at the very least problematic, if not impossible. Moreover, trust is intrinsic to a variety of issues with which Keynes, and subsequent Keynesianism have been concerned. In this paper we provide a general social theory conceptualisation of trust and then set out some of the areas where this concept resonates with the work of Keynes in terms of the role of conventions. Conventions quintessentially involve trust and that trust can be unstable, can be withdrawn and can require rebuilding. We illustrate this with reference to central bank policy and the Bank of England's introduction of Forward Guidance. Exploring the problem of trust in the context of banking also highlights a challenge for the continued relevance of Keynes' work. We now live in a neoliberal world and this provides a quite different context for state intervention than was previously the case. Keynes' work is now an argument for the alternative, and as such it requires more than a technical economic argument, it must also address the problem of trust in state policy-makers. We briefly illustrate the challenge this poses with reference to Europe

Investigation of the potential effects of bone turnover on x-ray fluorescence measurements of bone lead in young women

The potential effect of bone turnover on bone lead k X-Ray Fluorescence (XRF) measurements in young women were examined in this thesis. Published data has shown that men and women do not release lead back into blood from bone stores at the same rate until after menopause. Recently our laboratory re-investigated this phenomenon, and currently unpublished data showed that the release rate for young women may be better modelled through a non-linear function. One possible explanation is sex differences in cortical porosity. However, it was unknown whether cortical porosity could create a measurement artifact. Using 3D printing techniques, a phantom design was created that emulates cortical porosity at structural sizes of 300 microns. A calibration set of lead-doped cortical porosity phantoms were created and compared with past bone lead phantoms, there was no statistically significant differences observed. In phantoms with homogenous distributions of lead, cortical porosity does not appear to affect phantom measurements. Monte-Carlo simulations were performed using MCNP to verify and expand upon these results. Findings agreed with experimental results, and it was also shown that heterogenous distribution of lead did not affect K-XRF measurements until the distributions were extreme. Cortical porosity does not appear to result in XRF measurement artifacts, and the non-linearity in the relationship between blood and bone levels observed in young women appears to be real. Published analysis of in vivo data sets of young women found measurements in morbidly obese women were inaccurate. The effect of soft tissue overlay on bone lead measurements was therefore examined using MCNP. Results showed as soft tissue overlay thickness increases, the average measured bone lead value decreases. MCNP further showed that while the measured bone lead level in an individual is reduced, an increase in measurement uncertainty measurement masked the reduction. This may explain why the phenomenon has not been clearly observed and understood until now.ThesisMaster of Science (MSc

Imposing Hierarchy on a Graph

This paper investigates a way of imposing a hierarchy on a graph in order to explore relationships between elements of data. Imposing a hierarchy is equivalent to clustering. First a tree structure is imposed on the initial graph, then a k-partite structure is imposed on each previously obtained cluster. Imposing a tree exposes the hierarchical structure of the graph as well as providing an abstraction of the data. In this study three kinds of merge operations are considered and their composition is shown to yield a tree with a maximal number of vertices in which vertices in the tree are associated with disjoint connected subgraphs. These subgraphs are subsequently transformed into k-partite graphs using similar merge operations. These merges also ensure that the obtained tree is proper with respect to the hierarchy imposed on the data. A detailed example of the techniqueâs application in exposing the structure of protein interaction networks is described. The example focuses on the MAPK cell signalling pathway. The merge operations help expose where signal regulation occurs within the pathway and from other signalling pathways within the cell

Castro\u27s Shifters: Locating Variation in Political Discourse

In his trademark speeches, Fidel Castro casts himself in a variety of roles: supreme leader, member of government, revolutionary, worker, member of the Cuban populace, and the embodiment of the Cuban nation. Transcripts of Castro’s major speeches provide a rich data set that spans five decades (1959-present). Initial readings reveal his prominent use of the first person plural nosotros , which suggests an intriguing discourse of inclusiveness for this long-time authoritarian leader. In this poster, we identify Castro’s variable discursive referents for nosotros verbs in relation to era and topic of speech (i.e., history of the revolution, national goals and progress, or trouble talk). Variable rule analysis shows that in Castro’s earlier speeches, use of the royal we variant is favored: Llamábamos al Partido por la noche, y le preguntábamos si había llovido o no ( We called the Party the other night, and we asked if it had rained or not ). In contrast, the use of what we term the collective we is favored most heavily in speeches after the fall of the Soviet Union: No estamos produciendo para los burgueses, estamos produciendo para el pueblo ( We’re not producing for the bourgeoisie, we’re producing for the people ). The variation we encounter reflects Castro’s positioning of self relative to the people he is addressing. Castro, as leader of the perpetual revolutionary state, ostensibly erases the possibility of a public sphere existing apart from the government by constructing what the public thinks/expresses/wants as what the government [naturally] does. This is as we might expect in a Marxist dictatorship of the proletariat. Castro, however, achieves this conflation of public sphere and public authority in two ways in his speeches: first, he relocates public authority outside of the immediate social context, so that the role played by the Cuban public and the revolutionary government is one and the same when viewed in opposition to Yankee imperialism or memories of the Batista regime, for example. Second, by including himself in nosotros talk about workers and revolutionaries while standing over and addressing the Cuban public, Castro projects himself into the crowd. The effect of such talk is to offer an answer to the question, Who mediates between the private sphere and the government in a socialist society where each one is identified with the other? Castro proposes himself as the answer; he, not any autonomous, Habermasian sphere of rational debate, mediates between people’s private lives and the actions of state authority. Thus, what we term a personal public sphere provides a context for understanding the pattern of variation we observe in Castro’s speeches