The climatic character of the Auckland rural area

The characteristics of the climate of the rural area surrounding the Auckland urban area are discussed. Data used, is predominantly from published reports of the New Zealand Meteorological Service giving annual summaries of observations made at the various climatological, synoptic and rainfall recording stations. The mean characteristics of the area's climatic elements are considered together with their extremes. It is concluded that warm temperatures throughout the year, high humidity, variations in amount and. intensity of rainfall, prevailing westerly and infrequent easterly winds and high sunshine hours characterise the climate of this part of northern New Zealand

An Engineering Approach to the Variable Fluid Property Problem in Free Convection

An analysis is made for the variable fluid property problem for laminar free convection on an isothermal vertical flat plate. For a number of specific cases, solutions of the boundary layer equations appropriate to the variable property situation were carried out for gases and liquid mercury. Utilizing these findings, a simple and accurate shorthand procedure is presented for calculating free convection heat transfer under variable property conditions. This calculation method is well established in the heat transfer field. It involves the use of results which have been derived for constant property fluids, and of a set of rules (called reference temperatures) for extending these constant property results to variable property situations. For gases, the constant property heat transfer results are generalized to the variable property situation by replacing beta (expansion coefficient) by one over T sub infinity and evaluating the other properties at T sub r equals T sub w minus zero point thirty-eight (T sub w minus T sub infinity). For liquid mercury, the generalization may be accomplished by evaluating all the properties (including beta) at this same T sub r. It is worthwhile noting that for these fluids, the film temperature (with beta equals one over T sub infinity for gases) appears to serve as an adequate reference temperature for most applications. Results are also presented for boundary layer thickness and velocity parameters

Stabilizing unstable periodic orbits in the Lorenz equations using time-delayed feedback control

For many years it was believed that an unstable periodic orbit with an odd number of real Floquet multipliers greater than unity cannot be stabilized by the time-delayed feedback control mechanism of Pyragus. A recent paper by Fiedler et al uses the normal form of a subcritical Hopf bifurcation to give a counterexample to this theorem. Using the Lorenz equations as an example, we demonstrate that the stabilization mechanism identified by Fiedler et al for the Hopf normal form can also apply to unstable periodic orbits created by subcritical Hopf bifurcations in higher-dimensional dynamical systems. Our analysis focuses on a particular codimension-two bifurcation that captures the stabilization mechanism in the Hopf normal form example, and we show that the same codimension-two bifurcation is present in the Lorenz equations with appropriately chosen Pyragus-type time-delayed feedback. This example suggests a possible strategy for choosing the feedback gain matrix in Pyragus control of unstable periodic orbits that arise from a subcritical Hopf bifurcation of a stable equilibrium. In particular, our choice of feedback gain matrix is informed by the Fiedler et al example, and it works over a broad range of parameters, despite the fact that a center-manifold reduction of the higher-dimensional problem does not lead to their model problem.Comment: 21 pages, 8 figures, to appear in PR

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Resource /Energy Economics and Policy, Risk and Uncertainty,

Minotaurs, Not Centaurs:The Future of Manned-Unmanned Teaming

Contesting Paul Scharre’s influential vision of “centaur warfighting” and the idea that autonomous weapon systems will replace human warfighters, this article proposes that the manned-unmanned teams of the future are more likely to be minotaurs, teams of humans under the control, supervision, or command of artificial intelligence. It examines the likely composition of the future force and prompts a necessary conversation about the ethical issues raised by minotaur warfighting.</p

Minotaurs, Not Centaurs: The Future of Manned-Unmanned Teaming

Contesting Paul Scharre’s influential vision of “centaur warfighting” and the idea that autonomous weapon systems will replace human warfighters, this article proposes that the manned-unmanned teams of the future are more likely to be minotaurs, teams of humans under the control, supervision, or command of artificial intelligence. It examines the likely composition of the future force and prompts a necessary conversation about the ethical issues raised by minotaur warfighting

Progression from ocular hypertension to visual field loss in the English hospital eye service

Background There are more than one million National Health Service visits in England and Wales each year for patients with glaucoma or ocular hypertension (OHT). With the ageing population and an increase in optometric testing, the economic burden of glaucoma-related visits is predicted to increase. We examined the conversion rates of OHT to primary open-angle glaucoma (POAG) in England and assessed factors associated with risk of conversion. Methods Electronic medical records of 45 309 patients from five regionally different glaucoma clinics in England were retrospectively examined. Conversion to POAG from OHT was defined by deterioration in visual field (two consecutive tests classified as stage 1 or worse as per the glaucoma staging system 2). Cox proportional hazards models were used to examine factors (age, sex, treatment status and baseline intraocular pressure (IOP)) associated with conversion. Results The cumulative risk of conversion to POAG was 17.5% (95% CI 15.4% to 19.6%) at 5 years. Older age (HR 1.35 per decade, 95% CI 1.22 to 1.50, p<0.001) was associated with a higher risk of conversion. IOP-lowering therapy (HR 0.45, 95% CI 0.35 to 0.57, p<0.001) was associated with a lower risk of conversion. Predicted 5-year conversion rates for treated and untreated groups were 14.0% and 26.9%, respectively. Conclusion Less than one-fifth of OHT patients managed in glaucoma clinics in the UK converted to POAG over a 5-year period, suggesting many patients may require less intensive follow-up. Our study provides real-world evidence for the efficacy of current management (including IOP-lowering treatment) at reducing risk of conversion

Development of Local Hay Association

The need for a Hay marketing system had been obvious to hay sellers and agricultural leaders in Larue County for some time. Five or six hay producers had been selling mainly alfalfa hay to truckers, who would transport the hay to a buyer and reap the profit. Hay was mostly sold by the bale and at a low price. Because of the land and soil type, Larue County had a good potential to produce alfalfa as a cash crop. The development of this potential was being limited by an unreliable and unprofitable market. Given these conditions, the development of a local Hay Marketing Association was a good alternative which we pursued