Latent split of aggregate counts: revealing home deliveries per commodity types and potential freight trip implications

This paper suggests a joint econometric model that allows estimating latent marginal counts when only total counts and types of commodities purchased are available. The basis for this model is the Negative binomial hurdle model, which is expanded by incorporating different features for the latent classes, allowing eventual null latent counts for one or more classes. A validation procedure for the proposed splitting is discussed. The methodology was used to estimate and validate a model for the propensity to shop online and the corresponding number of shipments per commodity group. The results confirm existing research on online shopping behaviour: elderly is less likely to buy online, while high income, education and having kids motivate online shopping. The average online shopper receives 2.4 shipments/month (0.077 shipments/day), with variations in shipments and commodities depending on the consumer profile. Correlation between commodity groups reveals that consolidation can reduce shipments of up to 30%.publishedVersio

The effects of graded levels of calorie restriction : XI. Evaluation of the main hypotheses underpinning the life extension effects of CR using the hepatic transcriptome

We would like to acknowledge the BSU staff for their invaluable help with caring for the animals.Peer reviewedPublisher PD

The effects of graded levels of calorie restriction : IV. Non-linear change in behavioural phenotype of mice in response to short-term calorie restriction

We would like to acknowledge the BSU staff for their invaluable help with caring for the animals. The work was supported by the UK Biotechnology and Biological Sciences Research Council BBSRC (BB/G009953/1 and BB/J020028/1).Peer reviewedPublisher PD

The effects of graded levels of calorie restriction : III. Impact of short term calorie and protein restriction on mean daily body temperature and torpor use in the C57BL/6 mouse

GRANT SUPPORT This work was supported by BBSRC BB009953/1 awarded to JRS and SEM. PK and CD were funded by the Erasmus exchange programme. JRS, SEM, DD, CG, LC, JJDH, YW, DELP, DL and AD are members of the BBSRC China Partnership Award, BB/J020028/1.Peer reviewedPublisher PD

The effects of graded levels of calorie restriction : V. Impact of short term calorie and protein restriction on physical activity in the C57BL/6 mouse

Peer reviewedPublisher PD

On the Origin of the Slow Speed Solar Wind: Helium Abundance Variations

The First Ionization Potential (FIP) effect is the by now well known enhancement in abundance over photospheric values of Fe and other elements with first ionization potential below about 10 eV observed in the solar corona and slow speed solar wind. In our model, this fractionation is achieved by means of the ponderomotive force, arising as Alfv\'en waves propagate through or reflect from steep density gradients in the solar chromosphere. This is also the region where low FIP elements are ionized, and high FIP elements are largely neutral leading to the fractionation as ions interact with the waves but neutrals do not. Helium, the element with the highest FIP and consequently the last to remain neutral as one moves upwards can be depleted in such models. Here, we investigate this depletion for varying loop lengths and magnetic field strengths. Variations in this depletion arise as the concentration of the ponderomotive force at the top of the chromosphere varies in response to Alfv\'en wave frequency with respect to the resonant frequency of the overlying coronal loop, the magnetic field, and possibly also the loop length. We find that stronger depletions of He are obtained for weaker magnetic field, at frequencies close to or just above the loop resonance. These results may have relevance to observed variations of the slow wind solar He abundance with wind speed, with slower slow speed solar wind having a stronger depletion of He.Comment: 28 pages, 12 figures, accepted to Ap

Statistical properties of the attendance time series in the minority game

We study the statistical properties of the attendance time series corresponding to the number of agents making a particular decision in the minority game (MG). We focus on the analysis of the probability distribution and the autocorrelation function of the attendance over a time interval in the efficient phase of the game. In this regime both the probability distribution and the autocorrelation function are shown to have similar behaviour for time differences corresponding to multiples of $2\cdot 2^{m}$, which is twice the number of possible history bit strings in a MG with agents making decisions based on the most recent $m$ outcomes of the game.Comment: 3 pages, 4 Postscript figures, \documentstyle[aps,epsf]{revtex

The effects of graded levels of calorie restriction : II. Impact of short term calorie and protein restriction on circulating hormone levels, glucose homeostasis and oxidative stress in male C57BL/6 mice

This work was supported by BBSRC BB009953/1 awarded to JRS and SEM. PK and CD were funded by the Erasmus exchange programme. JRS, SEM, DD, CG, LC, JJDH, YW, DELP, DL and AD are members of the BBSRC China Partnership Award, BB/J020028/1.Peer reviewedPublisher PD

The effects of graded levels of calorie restriction : VIII. impact of short term calorie and protein restriction on basal metabolic rate in the C57BL/6 mouse

We are grateful to the animal house staff for looking after the animals. The work was supported by the UK Biotechnology and Biological Sciences Research Council BBSRC (grants BB/G009953/1 and BB/J020028/1) to JRS and SEM. DD was supported by a studentship from the Centre for Genome Enabled Biology and Medicine, Aberdeen, UK, and CG was supported by a BBSRC EastBio studentship. Joint meetings were funded by a BBSRC China partnering award (BB/JO20028/1).Peer reviewedPublisher PD