Technical note: A significance test for data-sparse zones in scatter plots

Data-sparse zones in scatter plots of hydrological variables can be of interest in various contexts. For example, a well-defined data-sparse zone may indicate inhibition of one variable by another. It is of interest therefore to determine whether data-sparse regions in scatter plots are of sufficient extent to be beyond random chance. We consider the specific situation of data-sparse regions defined by a linear internal boundary within a scatter plot defined over a rectangular region. An Excel VBA macro is provided for carrying out a randomisation-based significance test of the data-sparse region, taking into account both the within-region number of data points and the extent of the region. Example applications are given with respect to a rainfall time series from Israel and also to validation scatter plots from a seasonal forecasting model for lake inflows in New Zealand

An association between Waitaki River winter headwater flows and the Interdecadal Pacific Oscillation (IPO)

Expressed as 11-year running means (1945- 2008), winter headwater flows in the Waitaki River (New Zealand) and the IPO index show similar patterns in the way they vary over time. However, this effect is not evident in the other seasons. A possible explanation is the IPO in its positive phase is associated with warmer air temperatures in winter, but not in other seasons. Analysis of Mt Cook (Hermitage station) daily rainfalls suggests that warmer winter air temperatures on precipitation days are associated with higher mean daily precipitation, so the positive IPO may result in greater amounts of winter precipitation falling as rain rather than snow. This could provide the link between the winter IPO and headwater discharge. On the other hand, temperature is only weakly associated with precipitation magnitudes in other seasons, when higher average temperatures do not provide the same restricting effect on precipitation as in winter

Coordination when there are restricted and unrestricted options

One might expect that, in pure coordination games, coordination would become less frequent as the number of options increases. Contrary to this expectation, we report an experiment which found more frequent coordination when the option set was unrestricted than when it was restricted. To try to explain this result, we develop a method for eliciting the general rules that subjects use to identify salient options in restricted and unrestricted sets. We find that each such rule, if used by all subjects, would generate greater coordination in restricted sets. However, subjects tend to apply different rules to restricted and unrestricted sets

A Solution to Weed Control in Grassland Containing White Clover

Productive grass with white clover can lead to advantages both in forage quantity and quality, economics and in meeting wider expectations detailed in recent EU and UK policy. The ability to achieve this agronomic success is currently difficult due to a lack of options for broad spectrum weed control that also allow establishment or preservation of a white clover population. The aim of this paper is to demonstrate that 3730XL, developed by Corteva Agriscience, is a solution to this critical success factor. Data is presented from 16 efficacy trials (10 from established grassland and 5 from newly sown) where white clover cover of plots treated with 3730XL was recorded relative to an untreated plot. Data is also presented from 106 weed control trials, against a selection of species, demonstrating the efficacy of 3730XL split by grassland scenario. The evidence presented highlights the capability of 3730XL to both control a broad spectrum of weed species and allow the establishment or preservation of white clover. Consequently, growers are able to cultivate the associated benefits that this confers

Specification and verification of atomic operations in GPGPU programs

We propose a specification and verification technique based on separation logic to reason about data race freedom and functional correctness of GPU kernels that use atomic operations as synchronisation mechanism. Our approach exploits the notion of resource invariant from Concurrent Separation Logic (CSL) to capture the behaviour of atomic operations. However, because of the different memory levels in the GPU architecture, we adapt this notion of resource invariant to these memory levels, i.e., group resource invariants capture the behaviour of atomic operations that access locations in local memory, while kernel resource invariants capture the behaviour of atomic operations that access locations in global memory. We show soundness of our approach and we provide tool support that enables us to verify kernels from standard benchmarks suites

Local Expansion of Donation After Circulatory Death Kidney Transplant Activity Improves Waitlisted Outcomes and Addresses Inequities of Access to Transplantation

In the United Kingdom, donation after circulatory death (DCD) kidney transplant activity has increased rapidly, but marked regional variation persists. We report how increased DCD kidney transplant activity influenced waitlisted outcomes for a single center. Between 2002–2003 and 2011–2012, 430 (54%) DCD and 361 (46%) donation after brain death (DBD) kidney-only transplants were performed at the Cambridge Transplant Centre, with a higher proportion of DCD donors fulfilling expanded criteria status (41% DCD vs. 32% DBD; p = 0.01). Compared with U.K. outcomes, for which the proportion of DCD:DBD kidney transplants performed is lower (25%; p 65 years; waiting time 730 vs. 1357 days nationally; p < 0.001), who received predominantly DCD kidneys from older donors (mean donor age 64 years), whereas younger recipients received equal proportions of living donor, DBD and DCD kidney transplants. Death-censored kidney graft survival was nevertheless comparable for younger and older recipients, although transplantation conferred a survival benefit from listing for only younger recipients. Local expansion in DCD kidney transplant activity improves survival outcomes for younger patients and addresses inequity of access to transplantation for older recipients

Diagnostics and data fusion of robotic sensors

Robotic systems for remediation of hazardous waste sites must be highly reliable to avoid equipment failures and subsequent possible exposure of personnel to hazardous environments. Safe, efficient cleanup operations also require accurate, complete knowledge of the task space. This paper presents progress made on a 18 month program to meet these needs. To enhance robot reliability, a conceptual design of a monitoring and diagnostic system is being developed to predict the onset of mechanical failure modes, provide maximum lead time to make operational changes or repairs, and minimize the occurrence of on-site breakdowns. To ensure safe operation, a comprehensive software package is being developed that will fuse data from multiple surface mapping sensors and poses so as to reduce the error effects in individual data points and provide accurate 3-D maps of a work space

On the Influence of Pulse Shapes on Ionization Probability

We investigate analytical expressions for the upper and lower bounds for the ionization probability through ultra-intense shortly pulsed laser radiation. We take several different pulse shapes into account, including in particular those with a smooth adiabatic turn-on and turn-off. For all situations for which our bounds are applicable we do not find any evidence for bound-state stabilization.Comment: 21 pages LateX, 10 figure