The impact of a new regional air ambulance service on a large general hospital

Background: Helicopter air ambulance crews are influenced in their selection of the destination hospital for their patients by several factors including: distance from the scene; facilities, on site specialties, and senior cover of the receiving hospital; and the proximity of the helicopter landing area to the emergency department (ED). Only a limited number of hospitals have landing sites adjacent to the ED from which patients can be taken directly into the department (primary landing sites). Helicopter crews will often elect to over fly hospitals that do not have primary landing sites because secondary land transfers will add delays in delivering patients. Birmingham Heartlands Hospital has an elevated helideck adjacent to the ED. In October 2003, the Warwickshire and Northamptonshire Air Ambulance (WNAA) service was launched; the hospital sits on the western periphery of the area served by the service. Methods: Prospective data was collated on all patients brought by WNAA to Heartlands Hospital between 1 October 2003 and 31 August 2004. Results: In the 10 month period after the launch of the service, the helicopter delivered 83 patients to the ED; 74 of these were "off patch". This additional workload generated 163 ward days, 19 operative procedures, and 85 intensive care unit, high dependency unit, or coronary care unit days. The direct costs of this additional workload approached £160 000. Conclusions: In future discussions on the cost effectiveness of air ambulances, it will be important to consider both the direct and indirect costs to the receiving hospitals arising from the redistribution of emergency workload. Abbreviations: ED, emergency department; HDU, high dependency unit; HEMS, helicopter emergency medical service; ICU, intensive care unit; ISS, injury severity score; WNAA, Warwickshire and Northamptonshire Air Ambulance; WMCAA, West Midlands County Air Ambulance

Are Public Housing Projects Good For Kids?

One goal of federal housing policy is to improve the prospects of children in poor families. But little research has been conducted into the effects on children of participation in housing programs, perhaps because it is difficult to find data sets with information about both participation and interesting outcome measures. This paper combines data from several sources to provide a first look at the effects of participation in public housing projects on housing quality and on the educational attainment of children. We first use administrative data from the Department of Housing and Urban Development to impute the probability that a Census household lives in a public housing project. We find that a higher probability of living in a project is associated with poorer outcomes. We then use a two-sample instrumental variables (TSIV) technique to combine information on the probability of living in a project, obtained from the 1990 to 1995 Current Population Surveys, with information on outcomes obtained from the 1990 Census. The instrument common to both samples is an indicator equal to one if the household is entitled to a larger housing project unit because of the sex composition of the children in the household. Families entitled to a larger unit because of sex composition are 24 percent more likely to live in projects. When we control for omitted variables bias using TSIV, we find that project households are less likely to suffer from overcrowding and less likely to live in high-density complexes. Project children are also 12 to 17 percentage points less likely to have been held back in school one or more grades, although this effect is confined to boys. Thus, most families do not face a tradeoff between housing quality and child outcomes—the average project improves both.

Contingent plan structures for spacecraft

Most current AI planners build partially ordered plan structures which delay decisions on action ordering. Such structures cannot easily represent contingent actions. A representation which can is presented. The representation has some other useful features: it provides a good account of the causal structure of a plan, can be used to describe disjunctive actions, and it offers a planner the opportunity of even less commitment than the classical partial order on actions. The use of this representation is demonstrated in an on-board spacecraft activity sequencing problem. Contingent plan execution in a spacecraft context highlights the requirements for a fully disjunctive representation, since communication delays often prohibit extensive ground-based accounting for remotely sensed information and replanning on execution failure

Marsupial lions and methodological omnivory: function, success and reconstruction in paleobiology

This is the author accepted manuscript. The final version is available from Springer via the DOI in this record.Historical scientists frequently face incomplete data, and lack direct experimental access to their targets. This has led some philosophers and scientists to be pessimistic about the epistemic potential of the historical sciences. And yet, historical science often produces plausible, sophisticated hypotheses. I explain this capacity to generate knowledge in the face of apparent evidential scarcity by examining recent work on Thylacoleo carnifex, the ‘marsupial lion’. Here, we see two important methodological features. First, historical scientists are methodological omnivores, that is, they construct purpose-built epistemic tools tailored to generate evidence about highly specific targets. This allows them to produce multiple streams of independent evidence and thus maximize their epistemic reach. Second, investigative scaffolding: research proceeds in a piece-meal fashion, information only gaining evidential relevance once certain hypotheses are well supported. I illustrate scaffolding in a discussion of the nature of functional ascription in paleobiology. Frequently, different senses of ‘function’ are not discriminated during paleobiological investigation—something which can mar adaptationist investigations of extant organisms. However, I argue that, due to scaffolding, conflating senses of ‘function’ can be the right thing to do. Coarse-grained functional hypotheses are required before it is clear what evidence could discriminate between more fine-grained ones. I draw on omnivory and scaffolding to argue that pessimists make a bad empirical bet. It is a bad idea to bet against the epistemic fortunes of such opportunistic and resourceful scientists, especially when we have reason to think we will systematically underestimate the amount of evidence ultimately available to them

Geoengineering tensions

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordThere has been much discussion of the moral, legal and prudential implications of geoengineering, and of governance structures for both the research and deployment of such technologies. However, insufficient attention has been paid to how such measures might affect geoengineering in terms of the incentive structures which underwrite scientific progress. There is a tension between the features that make science productive, and the need to govern geoengineering research, which has thus far gone underappreciated. I emphasize how geoengineering research requires governance which reaches beyond science’s traditional boundaries, and moreover requires knowledge which itself reaches beyond what we traditionally expect scientists to know about. How we govern emerging technologies should be sensitive to the incentive structures which drive science

Tablet computers in assessing performance in a high stakes exam : opinion matters

The authors would like to thank Dr Craig brown, University of Aberdeen for assistance with data analysis.Peer reviewedPublisher PD

Why experiments matter

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordExperimentation is traditionally considered a privileged means of confirmation. However, why and how experiments form a better confirmatory source relative to other strategies is unclear, and recent discussions have identified experiments with various modeling strategies on the one hand, and with ‘natural’ experiments on the other hand. We argue that experiments aiming to test theories are best understood as controlled investigations of specimens. ‘Control’ involves repeated, fine-grained causal manipulation of focal properties. This capacity generates rich knowledge of the object investigated. ‘Specimenhood’ involves possessing relevant properties given the investigative target and the hypothesis in question. Specimens are thus representative members of a class of systems, to which a hypothesis refers. It is in virtue of both control and specimenhood that experiments provide powerful confirmatory evidence. This explains the distinctive power of experiments: although modelers exert extensive control, they do not exert this control over specimens; although natural experiments utilize specimens, control is diminished.John Templeton Foundatio