Probability of noise- and rate-induced tipping

We propose an approximation for the probability of tipping when the speed of parameter change and additive white noise interact to cause tipping. Our approximation is valid for small to moderate drift speeds and helps to estimate the probability of false positives and false negatives in early-warning indicators in the case of rate- and noise-induced tipping. We illustrate our approximation on a prototypical model for rate-induced tipping with additive noise using Monte-Carlo simulations. The formula can be extended to close encounters of rate-induced tipping and is otherwise applicable to other forms of tipping. We also provide an asymptotic formula for the critical ramp speed of the parameter in the absence of noise for a general class of systems undergoing rate-induced tipping.Comment: 14 pages, 9 figures https://link.aps.org/doi/10.1103/PhysRevE.95.05220

Experiential science as a novel scientific discipline

This report was presented at the UK Organic Research 2002 Conference. This paper positions experiential science as a new discipline in science with its own characteristics and principles. New elements in experiential science are the recognition of unique patterns in relation to previous actions and the reflection on intuitive, unique actions. There is a need for a new vocabulary to develop experiential science as a novel discipline

Farm level factors associated with feather pecking in organic laying hens

Farm-level factors that could be associated with feather pecking of layers kept in organic farming systems were monitored in 63 flocks from 26 farms located in different areas of The Netherlands. Data on housing and management practices were collected and plumage damage as a measure of feather pecking was scored at 50 weeks of age or older. No or little plumage damage was found in 18 (29%) flocks, moderate damage in 12 (19%) flocks and severe damage in 33 (52%) flocks. A high percentage of hens in the flock using the outdoor run, a young age at purchase and an increasing number of cockerels present in the flock were found to significantly decrease feather pecking damage at 50 weeks or older. Factors associated with increased usage of the outdoor run were smaller flock size, a young age at purchase, an increasing number of cockerels present in the flock and a higher percentage of cover in the run. Based on the results organic farmers are likely to benefit from rearing their own layers. They should keep cockerels with their layers. Other practices resulting in low feather pecking damage are stimulating the use of the outdoor run by making it attractive with vegetative or artificial cover or keeping the flock size at around 500 birds