Exploring the utility of Bayesian Networks for modelling cultural ecosystem services: A canoeing case study.

Modelling cultural ecosystem services is challenging as they often involve subjective and intangible concepts. As a consequence they have been neglected in ecosystem service studies, something that needs remedying if environmental decision making is to be truly holistic. We suggest Bayesian Networks (BNs) have a number of qualities that may make them well-suited for dealing with cultural services. For example, they define relationships between variables probabilistically, enabling conceptual and physical variables to be linked, and therefore the numerical representation of stakeholder opinions. We assess whether BNs are a good method for modelling cultural services by building one collaboratively with canoeists to predict how the subjective concepts of fun and danger are impacted on by weir modification. The BN successfully captured the relationships between the variables, with model output being broadly consistent with verbal descriptions by the canoeists. There were however a number of discrepancies indicating imperfect knowledge capture. This is likely due to the structure of the network and the abstract and laborious nature of the probability elicitation stage. New techniques should be developed to increase the intuitiveness and efficiency of probability elicitation. The limitations we identified with BNs are avoided if their structure can be kept simple, and it is in such circumstances that BNs can offer a good method for modelling cultural ecosystem services

Two-Channel Totally Asymmetric Simple Exclusion Processes

Totally asymmetric simple exclusion processes, consisting of two coupled parallel lattice chains with particles interacting with hard-core exclusion and moving along the channels and between them, are considered. In the limit of strong coupling between the channels, the particle currents, density profiles and a phase diagram are calculated exactly by mapping the system into an effective one-channel totally asymmetric exclusion model. For intermediate couplings, a simple approximate theory, that describes the particle dynamics in vertical clusters of two corresponding parallel sites exactly and neglects the correlations between different vertical clusters, is developed. It is found that, similarly to the case of one-channel totally asymmetric simple exclusion processes, there are three stationary state phases, although the phase boundaries and stationary properties strongly depend on inter-channel coupling. An extensive computer Monte Carlo simulations fully support the theoretical predictions.Comment: 13 pages, 10 figure

Parallel algorithm with spectral convergence for nonlinear integro-differential equations

We discuss a numerical algorithm for solving nonlinear integro-differential equations, and illustrate our findings for the particular case of Volterra type equations. The algorithm combines a perturbation approach meant to render a linearized version of the problem and a spectral method where unknown functions are expanded in terms of Chebyshev polynomials (El-gendi's method). This approach is shown to be suitable for the calculation of two-point Green functions required in next to leading order studies of time-dependent quantum field theory.Comment: 15 pages, 9 figure

(Super)twistors and (super)strings

The Lagrangian formulation of the D=4 bosonic string and superstring in terms of the (super)twistors is considered. The (super)twistor form of the equations of motion is derived and the kappa-symmetry transformation for the supertwistors is given. It is shown that the covariant kappa-symmetry gauge fixation results in the action quadratic in the (super)twistor variables.Comment: LaTeX, 17 page

A retrospective database study of oral corticosteroid and bisphosphonate prescribing patterns in England

© 2020, The Author(s). Exposure to oral corticosteroids (OCS) is associated with an increased risk of osteoporosis and fragility fractures. Guidelines suggest bisphosphonate (BP) therapy as the first-line treatment of glucocorticoid-induced osteoporosis (GIOP). This population study used publicly available data, including prescription annual cost analysis and monthly practice-level data. Our aim was to examine the prescribing of OCS and BP at practice level and investigate reasons for variation using a mixed-effect negative binomial regression analysis. There was a rise in OCS and BP prescriptions of 55% and 1200% from 1998 to 2018, respectively. Of the 6586 included practices, the median (IQR) of OCS and BP prescriptions were 120.8 (84.8–160.4) and 107.7 (73.8–147.4) per 1000 patients, respectively. Asthma and chronic obstructive pulmonary disease (COPD) were significantly associated with OCS use (p < 0.0001), but only COPD was associated with BP use (p < 0.0001). Higher OCS prescribing rates were associated with higher BP prescribing rates (5th to 1st quintile—IRR = 1.99; 95% CI: 1.88–2.10). Practice list size, deprivation and advanced age were all associated with both drugs (p < 0.0001). In conclusion, although OCS use is positively associated with BP prescription, variation among practices and CCGs exists. The variation in prescribing suggests there is still a need to improve GIOP prevention

B\"{a}cklund transformations for the KP and mKP hierarchies with self-consistent sources

Using gauge transformations for the corresponding generating pseudo-differential operators $L^n$ in terms of eigenfunctions and adjoint eigenfunctions, we construct several types of auto-B\"{a}cklund transformations for the KP hierarchy with self-consistent sources (KPHSCS) and mKP hierarchy with self-consistent sources (mKPHSCS) respectively. The B\"{a}cklund transformations from the KPHSCS to mKPHSCS are also constructed in this way.Comment: 22 pages. to appear in J.Phys.