Outperformance in exchange-traded fund pricing deviations: Generalized control of data snooping bias

An investigation into exchange-traded fund (ETF) outperforrnance during the period 2008-2012 is undertaken utilizing a data set of 288 U.S. traded securities. ETFs are tested for net asset value (NAV) premium, underlying index and market benchmark outperformance, with Sharpe, Treynor, and Sortino ratios employed as risk-adjusted performance measures. A key contribution is the application of an innovative generalized stepdown procedure in controlling for data snooping bias. We find that a large proportion of optimized replication and debt asset class ETFs display risk-adjusted premiums with energy and precious metals focused funds outperforming the S&P 500 market benchmark. 

Exchange between sub-surface and surface oxygen vacancies on CeO2(111):a new surface diffusion mechanism

Using first principles calculations for O vacancy diffusion on CeO2(111), we locate a surface diffusion mechanism, the two-step O vacancy exchange one, which is more favored than the most common hopping mechanism. By analyzing the results, we identify quantitatively the physical origin of why the two-step exchange mechanism is preferred.

Knowledge Exchange, Spatial Analysis & Healthy Urban Environments (KESUE): Project Report

The Knowledge Exchange, Spatial Analysis and Healthy Urban Environments (KESUE) project has extended work previously undertaken by a QUB team of inter-disciplinary researchers engaged with the Physical Activity in the Regeneration of Connswater (PARC) project (Tully et al, 2013). The PARC project focussed on parts of East Belfast to assess the health impact of the Connswater Community Greenway. The KESUE project has aimed to extend some of the tools used initially in East Belfast so that they have data coverage of all of Belfast and Derry-Londonderry. The purpose of this has been to enable the development of evidence and policy tools that link features of the built environment with physical activity in these two cities. The project has used this data to help shape policy decisions in areas such as physical activity, park management, public transport and planning.

Working with a range of local partners who part-funded the project (City Councils in Belfast and Derry-Londonderry, Public Health Agency, Belfast Healthy Cities and Department of Regional Development), this project has mapped all the footpaths in the two cities (covering 37% of the NI population) and employed this to develop evidence used in strategies related to healthy urban planning. Using Geographic Information Systems (GIS), the footpath network has been used as a basis for a wide range of policy-relevant analyses including pedestrian accessibility to public facilities, site options for new infrastructure and assessing how vulnerable groups can access services such as pharmacies. Key outputs have been Accessibility Atlases and maps showing how walkability of the built environment varies across the two cities.

In addition to generating this useful data, the project included intense engagement with potential users of the research, which has led to its continued uptake in a number of policies and strategies, creating a virtuous circle of research, implementation and feedback. The project has proved so valuable to Belfast City Council that they have now taken on one of the researchers to continue the work in-house.

Functional and pharmacological characterization of volume-regulated anion channels in human normal and cystic fibrosis bronchial and nasal epithelial cells

Volume-regulated anion channels (VRACs) are widely present in various cell types and have important functions ranging from regulatory volume decrease to control of cell proliferation and apoptosis. Here we aimed to compare the biophysical features and pharmacological profiles of VRAC currents in healthy and cystic fibrosis (CF) respiratory epithelial cells in order to characterize these currents both functionally and pharmacologically. Whole-cell electrophysiology was used to characterize the VRAC current in normal (16HBE14o-; HBE) and CF cell lines (CFBE14o-; CFBE), as well as in native human nasal epithelial cells. Application of hypotonic solution produced current responses of similar sizes in both HBE and CFBE cells. Biophysical properties of VRACs, such as instantaneous activation and deactivation upon voltage step, some inactivation at potentials positive to 40 mV and outwardly-rectifying I-V curves, were indistinguishable in both cell types. Extensive pharmacological analysis of the currents revealed a similar pharmacological profile in response to three blockers--NPPB, DCPIB and DIDS. Native primary human nasal epithelial cells from both healthy and CF volunteers also showed typical VRAC responses of comparable sizes. VRACs in these cells were more sensitive to external solution hypotonicity compared to HBE and CFBE cells. In all cell types studied robust VRAC currents could be induced at constant cell volume by G-protein activation with GTPγS infusion. This study provides the first extensive comparative functional and pharmacological analysis of VRAC currents in normal and CF airway epithelial cells and shows that VRACs are unimpaired molecularly or functionally in CF.

Effect of cation structure on the oxygen solubility and diffusivity in a range of bis{(trifluoromethyl)sulfonyl}imide anion based ionic liquids for lithium-air battery electrolytes

This paper reports on the solubility and diffusivity of dissolved oxygen in a series of ionic liquids (ILs) based on the bis{(trifluoromethyl)sulfonyl}imide anion with a range of related alkyl and ether functionalised cyclic alkylammonium cations. Cyclic voltammetry has been used to observe the reduction of oxygen in ILs at a microdisk electrode and chronoamperometric measurements have then been applied to simultaneously determine both the concentration and the diffusion coefficient of oxygen in the different ILs. The viscosity of the ILs and the calculated molar volume and free volume is also reported. It is found that, within this class of ILs, the oxygen diffusivity generally increases with decreasing viscosity of the neat IL. An inverse relationship between oxygen solubility and IL free volume is reported for the two IL families implying oxygen is not simply occupying the available empty space. In addition, it is reported that the introduction of ether-group into the IL cation structure promotes the diffusivity of dissolved oxygen but reduces the solubility of the gas.

Novel precipitated zirconia-based DGT technique for high-resolution imaging of oxyanions in waters and sediments

Water-sediment exchange is a fundamental component of oxyanion cycling in the environment. Yet, many of the (im)mobilization processes overlay complex spatial and temporal redox regimes that occur within millimeters of the interface. Only a few methods exist that can reliably capture these porewater fluxes, with the most popular being high-resolution diffusive gradients in thin films (HR-DGT). However, functionality of HR-DGT is restricted by the availability of suitable analyte binding agents within the sampler, which must be simple to cast and homogeneously distributed in the binding layer, exhibit adequate sorption capacities, be resistive to chemical change, and possess a very fine particle size (≤10 μm). A novel binding layer was synthesized to meet these requirements by in situ precipitation of zirconia into a precast hydrogel. The particle diameter ≤0.2 μm of zirconia in this precipitated gel was uniform and at least 50-times smaller than the conventional molding approach. Further, this gel had superior binding and stability characteristics compared with the commonly used ferrihydrite HR-DGT technique and could be easily fabricated as an ultrathin gel (60 μm) for simultaneous oxygen imaging in conjunction with planar-optodes. Chemical imaging of anion and oxygen fluxes using the new sampler were evaluated on Lake Taihu sediments.

Is it time for standards and a common data exchange format for digital image analysis?

Digital image analysis is at a crossroads. While the technology has made great strides over the past few decades, there is an urgent need for image analysis to inform the next wave of large scale tissue biomarker discovery studies in cancer. Drawing parallels from the growth of next generation sequencing, this presentation will consider the case for a common language or standard format for storing and communicating digital image analysis data. In this context, image analysis data comprises more than simply an image with markups and attached key-value pair metrics. The desire to objectively benchmark competing platforms or a push for data to be deposited to public repositories much like genomics data may drive the need for a standard that also encompasses granular, cell-by-cell data.