A global function for transcription factors in assisting RNA polymerase II termination.

The role of transcription factors (TFs) on nucleosome positioning, RNA polymerase recruitment, and transcription initiation has been extensively characterized. Here, we propose that a subset of TFs such as Reb1, Abf1, Rap1, and TFIIIB also serve a major function in partitioning transcription units by assisting the Nrd1p-Nab3p-Sen1p Pol II termination pathway

High-order half-integral conservative post-Newtonian coefficients in the redshift factor of black hole binaries

The post-Newtonian approximation is still the most widely used approach to obtaining explicit solutions in general relativity, especially for the relativistic two-body problem with arbitrary mass ratio. Within many of its applications, it is often required to use a regularization procedure. Though frequently misunderstood, the regularization is essential for waveform generation without reference to the internal structure of orbiting bodies. In recent years, direct comparison with the self-force approach, constructed specifically for highly relativistic particles in the extreme mass ratio limit, has enabled preliminary confirmation of the foundations of both computational methods, including their very independent regularization procedures, with high numerical precision. In this paper, we build upon earlier work to carry this comparison still further, by examining next-to-next-to-leading order contributions beyond the half integral 5.5PN conservative effect, which arise from terms to cubic and higher orders in the metric and its multipole moments, thus extending scrutiny of the post-Newtonian methods to one of the highest orders yet achieved. We do this by explicitly constructing tail-of-tail terms at 6.5PN and 7.5PN order, computing the redshift factor for compact binaries in the small mass ratio limit, and comparing directly with numerically and analytically computed terms in the self-force approach, obtained using solutions for metric perturbations in the Schwarzschild space-time, and a combination of exact series representations possibly with more typical PN expansions. While self-force results may be relativistic but with restricted mass ratio, our methods, valid primarily in the weak-field slowly-moving regime, are nevertheless in principle applicable for arbitrary mass ratios.Comment: 33 pages, no figure; minor correction

Exploring the reality of density substructures in the Palomar 5 stellar stream

We present an analysis of the presence of substructures in the stellar stream of the Palomar 5 globular cluster, as derived from Sloan Digital Sky Survey data. Using a matched filter technique, we recover the positions and sizes of overdensities reported in previous studies. To explore the reality of these structures, we also create an artificial model of the stream, in which we construct a realistic background on top of which we add a perfectly smooth stream structure, taking into account the effects of photometric completeness and interstellar extinction. We find that the smooth artificial stream then shows similarly-pronounced substructures as the real structure. Interestingly, our best-fit N-body simulation does display real projected density variations linked to stellar epicyclic motions, but these become less significant when taking into account the SDSS star-count constraints. The substructures found when applying our matched filter technique to the N-body particles converted into observable stars are thus mostly unrelated to these epicyclic motions. This analysis suggests that the majority of the previously-detected substructures along the tidal tail of Palomar 5 are artefacts of observational inhomogeneities.Comment: 10 pages, 9 figures, accepted for publication in MNRA

Non-Parametric Direct Multi-step Estimation for Forecasting Economic Processes

We evaluate the asymptotic and finite-sample properties of direct multi-step estimation (DMS) for forecasting at several horizons. For forecast accuracy gains from DMS in finite samples, mis-specification and non-stationarity of the DGP are necessary, but when a model is well-specified, iterating the one-step ahead forecasts may not be asymptotically preferable. If a model is mis-specified for a non-stationary DGP, omitting either negative residual serial correlation or regime shifts, DMS can forecast more accurately. Monte Carlo simulations clarify the non-linear dependence of the estimation and forecast biases on the parameters of the DGP, and explain existing results.Adaptive estimation, multi-step estimation, dynamic forecasts, model mis-specification.

Half-integral conservative post-Newtonian approximations in the redshift factor of black hole binaries

Recent perturbative self-force computations (Shah, Friedman & Whiting, submitted to Phys. Rev. {\bf D}, arXiv:1312.1952 [gr-qc]), both numerical and analytical, have determined that half-integral post-Newtonian terms arise in the conservative dynamics of black-hole binaries moving on exactly circular orbits. We look at the possible origin of these terms within the post-Newtonian approximation, find that they essentially originate from non-linear "tail-of-tail" integrals and show that, as demonstrated in the previous paper, their first occurrence is at the 5.5PN order. The post-Newtonian method we use is based on a multipolar-post-Minkowskian treatment of the field outside a general matter source, which is re-expanded in the near zone and extended inside the source thanks to a matching argument. Applying the formula obtained for generic sources to compact binaries, we obtain the redshift factor of circular black hole binaries (without spins) at 5.5PN order in the extreme mass ratio limit. Our result fully agrees with the determination of the 5.5PN coefficient by means of perturbative self-force computations reported in the previously cited paper.Comment: 18 pages, no figures, references updated and minor corrections include

Behavioural interventions for weight management in pregnancy: A systematic review of quantitative and qualitative data

Objective: To assess the effectiveness of dietary with or without physical activity interventions to prevent excessive weight gain in pregnancy and explore the factors that influence intervention effectiveness. Design: Systematic review, including a meta-analysis of controlled trials of interventions to prevent excessive weight gain during pregnancy and a thematic synthesis of qualitative studies that investigated the views of women on weight management during pregnancy. Data sources: Eleven electronic bibliographic databases, reference list of included studies, relevant review articles and experts in the field. Review methods: Two independent reviewers extracted data. RevMan software was used to perform the meta-analyses. Qualitative data was subject to thematic analysis. Both quantitative and qualitative data were aligned using a matrix framework. Results: Five controlled trials and nine qualitative studies were included. The overall pooled effect size found no significant difference in gestational weight gain amongst participants in the interventions group compared with the control group (mean difference -1.88kg CI -4.34 to 0.59). The study designs, participants and interventions all varied markedly and there was significant heterogeneity within this comparison in the meta-analysis (I2 76%). Subgroup and sensitivity analysis did not identify contextual elements that influenced the effectiveness of the intervention. In a thematic analysis of the qualitative studies, three major themes emerged relating to women’s views of weight management in pregnancy; pregnancy as a time of transition and change, conflicting and contradictory messages, a perceived lack of control. When the results of both quantitative and qualitative data were aligned it was clear that some of the barriers that women described in achieving healthy weight gain in pregnancy were not addressed by the interventions evaluated. This may have contributed to the limited effectiveness of the interventions. Conclusions: Despite intense and often tailored interventions there was no statistically significant effect on weight gain during pregnancy. Inadequate and often contradictory information regarding healthy weight management was reported by women in qualitative studies and this was addressed in the interventions but in itself was insufficient to lead to reduced weight gain. Multiple types of interventions, including community based strategies, are needed to address this complex health problem

Inverse Scattering and Acousto-Optic Imaging

We propose a tomographic method to reconstruct the optical properties of a highly-scattering medium from incoherent acousto-optic measurements. The method is based on the solution to an inverse problem for the diffusion equation and makes use of the principle of interior control of boundary measurements by an external wave field.Comment: 10 page

Anderson-like impurity in the one-dimensional t-J model: formation of local states and magnetic behaviour

We consider an integrable model describing an Anderson-like impurity coupled to an open $t$--$J$ chain. Both the hybridization (i.e. its coupling to bulk chain) and the local spectrum can be controlled without breaking the integrability of the model. As the hybridization is varied, holon and spinon bound states appear in the many body ground state. Based on the exact solution we study the state of the impurity and its contribution to thermodynamic quantities as a function of an applied magnetic field. Kondo behaviour in the magnetic response of the impurity can be observed provided that its parameters have been adjusted properly to the energy scales of the holon and spinon excitations of the one-dimensional bulk.Comment: 32 pages, 11 figure