Verification of random behaviours

We introduce abstraction in a probabilistic process algebra. The process algebra can be employed for specifying processes that exhibit both probabilistic and non-deterministic choices in their behaviours. Several rules and axioms are identified, allowing us to rewrite processes to less complex processes by removing redundant internal activity. Using these rules, we have successfully conducted a verification of the Concurrent Alternating Bit Protocol. The verification shows that after abstraction of internal activity, the protocol behaves as a buffer

A pilot study on the use of tracking technology: Feasibility, acceptability, and benefits for people in early stages of dementia and their informal caregivers

Objectives: Caregivers and clinicians may be confronted with the dilemma whether to allow people in early stages of dementia to go outside independently with the risk of getting lost, or to limit their autonomy and mobility. Newly available technology may offer a solution. This pilot study is focused on the feasibility, acceptability, and effectiveness of a three-month use of Global Positioning System (GPS) by care receivers and caregivers. Method: Numbers and percentages of participants with positive responses to self-report questions were calculated. Differences between the pre- and post-test scores of role-overload and worry were tested with paired t-tests and effect-sizes were calculated. Results: Of the 33 dyads of care receivers and caregivers, 28 remained in the study (dropout rate 15%). The majority of the caregivers was able to use the technology and integrate the use into their daily routines and would recommend the use of GPS. Almost half of the participants with dementia experienced more freedom and were less worried when they were outside unaccompanied, a quarter mentioned that they were more outside independently and a fifth that they had less conflicts with their caregiver after three months. Caregivers showed a trend to feel less worried, especially caregivers who could reach their relative using the telephone connection. No changes in caregivers feelings of role-overload were found. Conclusion: The GPS device used in this study seems to be promising for people in early stages of dementia and their informal caregivers. A next step is to carry out a randomized controlled trial. © 2012 Taylor and Francis Group, LLC

Message sequence charts in the software engineering process

The software development process benefits from the use of Message Sequence Charts (MSC), which is a graphical language for displyaing the interaction behaviour of a system. We describe canonical applications of MSC independent of any software development methodology. We illustrate the use of MSC with a case study: the Meeting Scheduler

Genetic barcoding of marine zooplankton using the MinIon sequencer

Biomonitoring is a way to determine the biodiversity and ecological status of an ecosystem. This is important in a world where species are lost at an alarming rate. Animal species can be identified during biomonitoring with various methods. One of these is metabarcoding which uses genetic markers isolated from a DNA extract from the biological community under study. These can then be sequenced with one of the many available platforms. Recently, the British company Oxford Nanopore Technologies has developed a revolutionary technology (MinION) has made sequencing much more accessible. In this research, it was investigated whether it is possible to use this MinION sequencer for metabarcoding of marine zooplankton communities. Each step of the protocol was optimised, after which it was applied to samples taken during a biomonitoring campaign on the North Sea. Different DNA extraction techniques are tested, after which PCR amplification and purification are optimized by selection of an optimal primer set, PCR master mix, inhibition prevention measures and purification protocols. The amplicons were then sequenced and subdivided into species using a reference database. Finally, a comparison was made with a ZooScan analysis in which species are determined based on their morphology. The results largely conform to ZooScan determinations and show no discrepancies from what was found in the literature. Although further research in data processing is required, it can be concluded that metabarcoding with MinION sequencing is a valuable innovation in the field of biomonitoring

Abstraction in parameterised Boolean equation systems

We present a general theory of abstraction for a variety of verification problems. Our theory is set in the framework of parameterized Boolean equation systems. The power of our abstraction theory is compared to that of generalised Kripke modal transition systems (GTSs). We show that for model checking the modal µ-calculus, our abstractions can be exponentially more succinct than GTSs and our theory is as complete as the GTS framework for abstraction. Furthermore, we investigate the completeness of our theory for verification problems other than the modal µ-calculus. We illustrate the potential of our theory through case studies using the first-order modal µ-calculus and a real-time extension thereof, conducted using a prototype implementation of a new syntactic transformation for equation systems

Advances in guava propagation.

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The diverse nature of island isolation and its effect on land bridge insular faunas

Aim: Isolation is a key factor in island biology. It is usually defined as the distance to the geographically nearest mainland, but many other definitions exist. We explored how testing different isolation indices affects the inference of impacts of isolation on faunal characteristics. We focused on land bridge islands and compared the relationships of many spatial and temporal (i.e., through time) isolation indices with community‐, population‐ and individual‐level characteristics (species richness, population density and body size, respectively). Location: Aegean Sea islands, Greece. Time period: Current. Taxon: Many animal taxa. Methods: We estimated 21 isolation indices for 205 islands and recorded species richness data for 15 taxa (invertebrates and vertebrates). We obtained body size data for seven lizard species and population density data for three. We explored how well indices predict each characteristic, in each taxon, by conducting a series of ordinary least squares regressions (controlling for island area when needed) and a meta‐analysis. Results: Isolation was significantly (and negatively) associated with species richness in 10 of 15 taxa. It was significantly (and positively) associated with body size in only one of seven species and was not associated with population density. The effect of isolation on species richness was much weaker than that of island area, regardless of the index tested. Spatial indices generally out‐performed temporal indices, and indices directly related to the mainland out‐performed those related mainly to neighbouring islands. No index was universally superior to others, including the distance to the geographically nearest mainland. Main conclusions: The choice of index can alter our perception of the impacts of isolation on biological patterns. The nearly automatic, ubiquitous use of distance to the geographically nearest mainland misrepresents the complexity of the effects of isolation. We recommend the simultaneous testing of several indices that represent different aspects of isolation, in order to produce more constructive and thorough investigations and avoid imprecise inference

Variable number of tandem repeats in clinical strains of Haemophilus influenzae

An algorithm capable of identifying short repeat motifs was developed and used to screen the whole genome sequence available for Haemophilus influenzae, since some of these repeats have been shown to affect bacterial virulence. Various di- to hexanucleotide repeats were identified, confirming and extending previous findings on the existence of variable-number-of-tandem-repeat loci (VNTRs). Repeats with units of 7 or 8 nucleotides were not encountered. For all of the 3- to 6-nucleotide repeats in the H. influenzae chromosome, PCR tests capable of detecting allelic polymorphisms were designed. Fourteen of 18 of the potential VNTRs were indeed highly polymorphic when different strains were screened. Two of the potential VNTRs appeared to be short and homogeneous in length; another one may be specific for the H. influenzae Rd strain only. One of the primer sets generated fingerprint-type DNA banding patterns. The various repeat types differed with respect to intrinsic stability as well. It was noted for separate colonies derived from a single clinical specimen or strains passaged for several weeks on chocolate agar plates that the lengths of the VNTRs did not change. When several strains from different patients infected during an outbreak of lung disease were analyzed, increased but limited variation was encountered in al