Time Series Forecasting: The Case for the Single Source of Error State Space

The state space approach to modelling univariate time series is now widely used both in theory and in applications. However, the very richness of the framework means that quite different model formulations are possible, even when they purport to describe the same phenomena. In this paper, we examine the single source of error [SSOE] scheme, which has perfectly correlated error components. We then proceed to compare SSOE to the more common version of the state space models, for which all the error terms are independent; we refer to this as the multiple source of error [MSOE] scheme. As expected, there are many similarities between the MSOE and SSOE schemes, but also some important differences. Both have ARIMA models as their reduced forms, although the mapping is more transparent for SSOE. Further, SSOE does not require a canonical form to complete its specification. An appealing feature of SSOE is that the estimates of the state variables converge in probability to their true values, thereby leading to a formal inferential structure for the ad-hoc exponential smoothing methods for forecasting. The parameter space for SSOE models may be specified to match that of the corresponding ARIMA scheme, or it may be restricted to meaningful sub-spaces, as for MSOE but with somewhat different outcomes. The SSOE formulation enables straightforward extensions to certain classes of non-linear models, including a linear trend with multiplicative seasonals version that underlies the Holt-Winters forecasting method. Conditionally heteroscedastic models may be developed in a similar manner. Finally we note that smoothing and decomposition, two crucial practical issues, may be performed within the SSOE framework.ARIMA, Dynamic Linear Models, Equivalence, Exponential Smoothing, Forecasting, GARCH, Holt's Method, Holt-Winters Method, Kalman Filter, Prediction Intervals.

Maps & Apps: Mobile Media Marketing Education for Food and Farm Entrepreneurs

With an increasing number of consumers using smartphones, tablets, and other mobile devices to find and interact with local businesses, Ohio State University Extension developed a new curriculum aimed at improving market access for food and farm entrepreneurs. The literature review, curriculum framework, and lessons learned shared in this article can be used by Extension professionals to improve their own online presence, as well as by educators working with entrepreneurs and community leaders

Race and the evaluation of signal callers in the national football league

Until recently, the position of quarterback in the National Football League (NFL) was not an option for Black athletes. Today, many teams use Black quarterbacks, a development that might suggest race is no longer relevant when it comes to the evaluation of signal callers in the NFL. By modeling quarterback performance and salary over 1995-2006, we find that Black quarterbacks are more likely to run with the football, yet this skill is not compensated in the market. Furthermore, we find evidence of performance-related salary discrimination against Black quarterbacks in the top half of the salary distribution

Sustainability versus Heritage: A case study for use in teaching in Engineering Ethics

This is an Engineering Ethics case study from the IDEA CETL. It examines the case of a conflict between environmental issues (using sustainable timber) and protecting heritage (replacing like with like in a listed building). It raises issues such as heritage; sustainability; environment and culpable ignorance. The teaching format is a two hour session with small group discussions.

A tale of two audiences: Spectators, television viewers and outcome uncertainty in Spanish football

This paper tests for the impact of match outcome uncertainty on two types of audience for Spanish football, fans at the stadium and television viewers. We find that fans inside the stadium prefer games that are less and not more likely to finish with a close score. This is contrary to much theoretical literature in sports economics which argues that fans prefer close contests and imposes this assumption in formal modelling. We also find that television viewers prefer close contests to more predictable contests. The different preferences of fans inside the stadium and television viewers need to be reconciled by the league when considering the effectiveness of policies to redistribute resources amongst teams in the league. We use our empirical model to consider how this tension might be resolved so as to maximise total audience and total league revenues

Data from: Mixing of porpoise ecotypes in southwestern UK waters revealed by genetic profiling

Contact zones between ecotypes are windows for understanding how species may react to climate changes. Here, we analysed the fine-scale genetic and morphological variation in harbour porpoises (Phocoena phocoena) around the UK by genotyping 591 stranded animals at nine microsatellite loci. The data were integrated with a prior study to map at high resolution the contact zone between two previously identified ecotypes meeting in the northern Bay of Biscay. Clustering and spatial analyses revealed that UK porpoises are derived from two genetic pools with porpoises from the southwestern UK being genetically differentiated, and having larger body sizes compared to those of other UK areas. Southwestern UK porpoises showed admixed ancestry between southern and northern ecotypes with a contact zone extending from the northern Bay of Biscay to the Celtic Sea and Channel. Around the UK, ancestry blends from one genetic group to the other along a southwest--northeast axis, correlating with body size variation, consistent with previously reported morphological differences between the two ecotypes. We also detected isolation by distance among juveniles but not in adults, suggesting that stranded juveniles display reduced intergenerational dispersal. The fine-scale structure of this admixture zone raises the question of how it will respond to future climate change and provides a reference point for further study.,Data UK porpoises DRYADData UK porpoises including: stranding locations and dates, sex, age and body length of the animals (when known), and microsatellite genotyping. Note that EV104 was not considered because of null allele issues.Data_UKporpoises_DRYAD.xlsx

Processed line aerogravity data over the Institute and Moller region (2010/11 season)

During the 2010/2011 Antarctic field season a collaborative NERC AFI (Antarctic Funding Initiative) project studying the basal boundary conditions of the Institute & Moller ice streams, West Antarctica, collected ~25,000 km of new high quality aerogravity data. Data were acquired using Lacoste and Romberg air-sea gravity meter S83, mounted in the BAS aerogeophysically equipped Twin Otter "Bravo Lima". Data are provided as XYZ ASCII line data. Data were collected as part of the UK Natural Environment Research Council AFI grant NE/G013071/1

Transient amplification enhances the persistence of tropicalising coral assemblages in marginal high latitude environments

Predicting the viability of species exposed to increasing climatic stress requires an appreciation for the mechanisms underpinning the success or failure of marginal populations. Rather than traditional metrics of long-term population performance, here we illustrate that short-term (i.e., transient) demographic characteristics, including measures of resistance, recovery, and compensation, are fundamental in the poleward range expansion of hard corals, facilitating the establishment of coral populations at higher latitudes. Through the annual census of tropical and subtropical Acropora spp. colonies in Japan between 2017-2019, we show how enhanced transient amplification (i.e., short-term increases in population growth following disturbance) supports the persistence of coral assemblages within more variable high-latitude environments. The transient dynamics of both the tropical and subtropical assemblages were strongly influenced by their corresponding recruitment patterns. However, we demonstrate that variation in colony survival and fragmentation patterns between the two assemblages determines their relative capacities for transient amplification. This latitudinal variation in the transient dynamics of Acropora spp. assemblages emphasises that coral populations can possess the demographic plasticity necessary for exploiting more variable, marginal conditions