Formulating State Space Models in R with Focus on Longitudinal Regression Models

We provide a language for formulating a range of state space models with response densities within the exponential family. The described methodology is implemented in the R-package sspir. A state space model is specified similarly to a generalized linear model in R, and then the time-varying terms are marked in the formula. Special functions for specifying polynomial time trends, harmonic seasonal patterns, unstructured seasonal patterns and time-varying covariates can be used in the formula. The model is fitted to data using iterated extended Kalman filtering, but the formulation of models does not depend on the implemented method of inference. The package is demonstrated on three datasets.

A Modal Characterisation of Distributed Bisimulation

In this paper we consider the distributed bisimulation equivalence defined by Hennessy and Castellani and later developed by Castellani. We present a logic in the style of Hennessy-Milner logic to charaterize the equivalence, i.e. we seek a logic such that whenever two processes are distributed bisimulation equivalent, they satisfy the same set of formulae and vice versa. Furthermore, for a small subset of CCS we provide a proof system which is shown to be sound and complete. The proof system is structural both in the structure of formulae and in the structure of processes. For the case of parallel composition of processes we present inference rules defined via a new combinator introduced. The combinator in question is left merge, a special kind of parallel composition in which the left operand has precedence over the other and must perform the first action observed

Organic farming and multicriteria decisions: An economic survey

Organic food production is a sphere where decision making is multi-facetted and complex. This applies to producers, political decision makers and consumers alike. This paper provides an overview of the economic methods that can aid such multi criteria decision making. We first provide an outline of the many different Multi-Criteria Analysis (MCA) techniques available and their relative advantages and disadvantages. In addition, theoretical and practical problems related to the use of Cost-Benefit Analysis (CBA) and MCA respectively are briefly discussed. We then review the MCA literature on case studies on organic farming. Based on this review we provide directional markers for future research where MCA may possibly be applied and adapted in order to provide useful knowledge and support for decision makers in the context of organic farming

Defoliation reduces soil biota - and modifies stimulating effects of elevated CO₂

To understand the responses to external disturbance such as defoliation and possible feedback mechanisms at global change in terrestrial ecosystems, it is necessary to examine the extent and nature of effects on aboveground–belowground interactions. We studied a temperate heathland system subjected to experimental climate and atmospheric factors based on prognoses for year 2075 and further exposed to defoliation. By defoliating plants, we were able to study how global change modifies the interactions of the plant–soil system. Shoot production, root biomass, microbial biomass, and nematode abundance were assessed in the rhizosphere of manually defoliated patches of Deschampsia flexuosa in June in a full‐factorial FACE experiment with the treatments: increased atmospheric CO (2), increased nighttime temperatures, summer droughts, and all of their combinations. We found a negative effect of defoliation on microbial biomass that was not apparently affected by global change. The negative effect of defoliation cascades through to soil nematodes as dependent on CO (2) and drought. At ambient CO (2), drought and defoliation each reduced nematodes. In contrast, at elevated CO (2), a combination of drought and defoliation was needed to reduce nematodes. We found positive effects of CO (2) on root density and microbial biomass. Defoliation affected soil biota negatively, whereas elevated CO (2) stimulated the plant–soil system. This effect seen in June is contrasted by the effects seen in September at the same site. Late season defoliation increased activity and biomass of soil biota and more so at elevated CO (2). Based on soil biota responses, plants defoliated in active growth therefore conserve resources, whereas defoliation after termination of growth results in release of resources. This result challenges the idea that plants via exudation of organic carbon stimulate their rhizosphere biota when in apparent need of nutrients for growth

Modular State Space Analysis of Coloured Petri Nets

State Space Analysis is one of the most developed analysis methods for Petri Nets. The main problem of state space analysis is the size of the state spaces. Several ways to reduce it have been proposed but cannot yet handle industrial size systems.Large models often consist of a set of modules. Local properties of each module can be checked separately, before checking the validity of the entire system. We want to avoid the construction of a single state space of the entire system.When considering transition sharing, the behaviour of the total system can be capture by the state spaces of modules combined with a Synchronisation Graph. To verify that we do not lose information we show how the full state space can be conctructed.We show how it is possible to determine usual Petri Nets properites, without unfolding to the ordinary state space

Bovine α2-antiplasmin N-Terminal and reactive site sequence

AbstractBovine α2-antiplasmin (α2AP) has been purified and partially characterized. The amino acid composition is very similar to that of human α2AP, and the N-terminal (23 residues determined) and reactive site loop sequences (42 residues determined) are highly homologous to those of the human protein. Compared with human α2AP, bovine α2AP has an 18-residue N-terminal extension, homologous with part of the pre-sequence of human α2AP. A re-investigation of the N-terminal sequence of freshly prepared human α2AP reveals a new form extended by 12 residues