A comparison of the equivalent weights particle filter and the local ensemble transform Kalman filter in application to the barotropic vorticity equation

Data assimilation methods that work in high dimensional systems are crucial to many areas of the geosciences: meteorology, oceanography, climate science etc. The equivalent weights particle filter has been designed, and has recently been shown to, scale to problems that are of use to these communities. This article performs a systematic comparison of the equivalent weights particle filter with the established and widely used local ensemble transform Kalman filter. Both methods are applied to the barotropic vorticity equation for different networks of observations. In all cases it was found that the local ensemble transform Kalman filter produced lower root mean squared errors than the equivalent weights particle filter. The performance of the equivalent weights particle filter is shown to depend strongly on the form of nudging used, and a nudging term based on the local ensemble transform Kalman smoother is shown to improve the performance of the filter. This indicates that the equivalent weights particle filter must be considered as a truly 2-stage filter and not only by its final step which avoids weight collapse

A systematic method of parameterisation estimation using data assimilation

In numerical weather prediction, parameterisations are used to simulate missing physics in the model. These can be due to a lack of scientific understanding or a lack of computing power available to address all the known physical processes. Parameterisations are sources of large uncertainty in a model as parameter values used in these parameterisations cannot be measured directly and hence are often not well known; and the parameterisations themselves are also approximations of the processes present in the true atmosphere. Whilst there are many efficient and effective methods for combined state/parameter estimation in data assimilation (DA), such as state augmentation, these are not effective at estimating the structure of parameterisations. A new method of parameterisation estimation is proposed that uses sequential DA methods to estimate errors in the numerical models at each space-time point for each model equation. These errors are then fitted to pre-determined functional forms of missing physics or parameterisations that are based upon prior information. We applied the method to a one-dimensional advection model with additive model error, and it is shown that the method can accurately estimate parameterisations, with consistent error estimates. Furthermore, it is shown how the method depends on the quality of the DA results. The results indicate that this new method is a powerful tool in systematic model improvement

‘Chances are you’re about to lose’:new independent Australian safer gambling messages tested in UK and USA bettor samples

Current industry-developed safer gambling messages such as ‘Take time to think’ and ‘Gamble responsibly’ have been criticized as ineffective slogans. As a result, Australia has recently introduced seven independently-developed safer gambling messages. The UK Government intends to introduce independently-developed messages from 2024 onwards, and this measure could be similarly appropriate for the US states where sports betting has been legalized and gambling advertising has become pervasive. Given this context, the current study recruited race and sports bettors from the UK and USA to elicit their perceptions of the seven Australian safer gambling messages. Participants (N = 1865) rated on a Likert-scale seven newly introduced messages and two existing ones (‘Take time to think’ and ‘Gamble responsibly’) using seven evaluative statements. Participants also reported their levels of problem gambling severity. For most statements in both jurisdictions, the new messages performed significantly better than the existing ones. Specifically, the new messages were deemed more attention grabbing, applicable on a personal level, helpful to gamblers, and more likely to encourage cutbacks in gambling. The message that included a specific call to action (‘What are you prepared to lose today? Set a deposit limit’) was one of the best performing messages. Interaction effects observed in relation to jurisdiction, age, gender, and problem gambling severity were generally small enough to counteract the argument that different populations might benefit from substantially different messages. These findings add to previous research on the independent design of effective safer gambling messages

Ephemeral returns: Social network valuations and perceived privacy

This paper investigates the valuations of social media platforms (SMPs) in light of the recent initial public offering (IPO) of Snapchat. Innovative platforms with unproven business models and non-voting shares commanding relatively high valuations at IPO stage as well as a shift in investor profile towards personal rather than institutional investors have eerie connotations with the tech bubble of 2000. We posit that investors value a passive audience for SMPs rather than an active user community and apply potentially unrealistic customer lifetime values and expected user growth in a highly competitive market. We also posit that investors overestimate willingness to participate, the potential success in the adoption of paid services and do not account fully for perceived or real privacy features

Integrated Batch and Continuous Flow Process for the Synthesis of Goniothalamin.

An integrated batch and continuous flow process has been developed for the gram-scale synthesis of goniothalamin. The synthetic route hinges upon a telescoped continuous flow Grignard addition followed by an acylation reaction capable of delivering a racemic goniothalamin precursor (15) (20.9 g prepared over 3 hours), with a productivity of 7 g.h-1. An asymmetric Brown allylation protocol was also evaluated under continuous flow conditions. This approach employing (–)-Ipc2B(allyl) provided (S)-goniothalamin intermediate in 98% yield and 91.5% enantiomeric excess (ee) with a productivity of 1.8 g.h-1. For the final step, a ring-closing metathesis reaction was investigated under a variety of conditions in both batch and flow regimes. In a batch operation, Grubbs second-generation catalyst proved to be efficient and highly selective for the desired ring closure product over those arising from other modes of reactivity, and the reaction was complete in 1.5 h. In a flow operation, reactivity and selectivity was attenuated relative to batch mode, however after further optimisation, residence time could be reduced to 16 minutes with good selectivity and good yield of the desired product. A tube-in-tube reactor was investigated for in-situ ethylene removal to favor ring-closing over cross-metathesis, in this context. These results provide further evidence of the utility of flow chemistry for organometallic processing and reaction telescoping. Using the developed integrated batch and flow methods, a total of 7.75 g of goniothalamin (1) was synthesized

Thermal Energy Storage in Building Integrated Thermal Systems: A review. Part 1. Active storage systems

Energy consumed by heating, ventilation and air conditioning systems (HVAC) in buildings represents an important part of the global energy consumed in Europe. Thermal energy storage is considered as a promising technology to improve the energy efficiency of these systems, and if incorporated in the building envelope the energy demand can be reduced. Many studies are on applications of thermal energy storage in buildings, but few consider their integration in the building. The inclusion of thermal storage in a functional and constructive way could promote these systems in the commercial and residential building sector, as well as providing user-friendly tools to architects and engineers to help implementation at the design stage. The aim of this paper is to review and identify thermal storage building integrated systems and to classify them depending on the location of the thermal storage system.The work was carried out under the framework of the COST Action BISTS TU1205. The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007–2013) under grant agreement n° PIRSES-GA-2013-610692 (INNOSTORAGE). The authors from the University of Lleida would like to thank the Catalan Government for the quality accreditation given to their research group (2014 SGR 123). Alvaro de Gracia would like to thank Education Ministry of Chile for Grant PMI ANT1201