A Local Replacement of \u3ci\u3eBombus Ternarius\u3c/i\u3e by \u3ci\u3eBombus Terricola\u3c/i\u3e in Northern Wisconsin (Hymenoptera: Apidae)

During the last few years, the bumblebee Bombus ternarius Say has markedly decreased in numbers in Vilas County in northern Wisconsin while Bombus terricola Kirby has increased. The great ecological similarity of these species suggests that interspecific competition may cause or facilitate this replacement

A flight dynamics investigation of compound helicopter configurations

Compounding has often been proposed as a method to increase the maximum speed of the helicopter. There are two common types of compounding known as wing and thrust compounding. Wing compounding offloads the rotor at high speeds delaying the onset of retreating blade stall, hence increasing the maximum achieveable speed, whereas with thrust compounding, axial thrust provides additional propulsive force. The concept of compounding is not new but recently there has been a resurgence of interest in the configuration due to the emergence of new requirements for speeds greater than those of conventional helicopters. The aim of this paper is to investigate the dynamic stability characteristics of compound helicopters and compare the results with a conventional helicopter. The paper discusses the modelling of two compound helicopters, with the first model featuring a coaxial rotor and pusher propeller. This configuration is known as the coaxial compound helicopter. The second model, known as the hybrid compound helicopter, features a wing and two propellers providing thrust compounding. Their respective trim results are presented and contrasted with a baseline model. Furthermore, using a numerical differentiation technique, the compound models are linearised and their dynamic stability assessed. The results show that the frequency of the coaxial compound helicopter’s dutch roll mode is less than that of the baseline helicopter and there is also greater roll damping. With regards to the hybrid compound helicopter the results show greater heave damping and the stabilisation of the phugoid due to the addition of the wing and propellers

Improving rotorcraft survivability to RPG attack using inverse methods

This paper presents the results of a preliminary investigation of optimal threat evasion strategies for improving the survivability of rotorcraft under attack by rocket propelled grenades (RPGs). The basis of this approach is the application of inverse simulation techniques pioneered for simulation of aggressive helicopter manoeuvres to the RPG engagement problem. In this research, improvements in survivability are achieved by computing effective evasive manoeuvres. The first step in this process uses the missile approach warning system camera (MAWS) on the aircraft to provide angular information of the threat. Estimates of the RPG trajectory and impact point are then estimated. For the current flight state an appropriate evasion response is selected then realised via inverse simulation of the platform dynamics. Results are presented for several representative engagements showing the efficacy of the approach

Scottish contributions to rotary wing flight

This paper charts the history of rotorcraft development in Scotland. Beginning with the early efforts of Mumford to achieve rotor-borne flight, through the major technology advances of G and J Weir in the 30s and 40s up to present day activities. The paper shows that despite being a relatively small country, Scotland’s traditional expertise in engineering when applied to the development of rotorcraft,generated significant technological advances

Health effects of housing improvement: systematic review of intervention studies

OBJECTIVE: To review the evidence on the effects of interventions to improve housing on health. DESIGN: Systematic review of experimental and non-experimental housing intervention studies that measured quantitative health outcomes. DATA SOURCES: Studies dating from 1887, in any language or format, identified from clinical, social science, and grey literature databases, personal collections, expert consultation, and reference lists. MAIN OUTCOME MEASURES: Socioeconomic change and health, illness, and social measures. RESULTS: 18 completed primary intervention studies were identified. 11 studies were prospective, of which six had control groups. Three of the seven retrospective studies used a control group. The interventions included rehousing, refurbishment, and energy efficiency measures. Many studies showed health gains after the intervention, but the small study populations and lack of controlling for confounders limit the generalisability of these findings. CONCLUSIONS: The lack of evidence linking housing and health may be attributable to pragmatic difficulties with housing studies as well as the political climate in the United Kingdom. A holistic approach is needed that recognises the multifactorial and complex nature of poor housing and deprivation. Large scale studies that investigate the wider social context of housing interventions are required. [References: 42

Sensitivity-analysis method for inverse simulation application

An important criticism of traditional methods of inverse simulation that are based on the Newton–Raphson algorithm is that they suffer from numerical problems. In this paper these problems are discussed and a new method based on sensitivity-analysis theory is developed and evaluated. The Jacobian matrix may be calculated by solving a sensitivity equation and this has advantages over the approximation methods that are usually applied when the derivatives of output variables with respect to inputs cannot be found analytically. The methodology also overcomes problems of input-output redundancy that arise in the traditional approaches to inverse simulation. The sensitivity- analysis approach makes full use of information within the time interval over which key quantities are compared, such as the difference between calculated values and the given ideal maneuver after each integration step. Applications to nonlinear HS125 aircraft and Lynx helicopter models show that, for this sensitivity-analysis method, more stable and accurate results are obtained than from use of the traditional Newton–Raphson approach

Regional Unemployment Disparities.

In this paper we examine the nature of disparities in regional (State) unemployment rates in Australia over the period 1978-1999 and their relationship to the national unemployment rate. As a measure of dispersion we use the sum of the (weighted) deviations of regional unemployment rates from the national rate. We show that this figure may be interpreted as the number of new jobs or labour force movements that would be needed to even out unemployment rates between regions, expressed as a proportion of the total number currently employed in all regions. Using co-integration analysis, we find that there is a (long-run) relationship between the degree of dispersion in the regional unemployment rates and the level of the national unemployment rate. The relationship between the two is negative implying that, as the national unemployment rate falls, micro and/or differentiated labour markets policies need to bite harder (and affect proportionately more people) if equity in unemployment across regions is to be maintained. We also find that the trade-off between dispersion and unemployment has become steeper in the period following significant deregulation of the Australian economy in the early Nineteen-Eighties. It would appear likely that this reflects an increase in differences in the Natural Rate of Unemployment between the regions since that time.UNEMPLOYMENT ; REGIONAL DEVELOPMENT

Continuing education: The 1998 survey of the Royal Australasian College of Dental Surgeons

The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.Background: Continuing education (CE) is an essential professional activity. In the last decade, CE has been actively pursued by the medical profession in Australia and abroad. However, the uptake of CE in dentistry has been much slower and there is minimal Australian data on dental CE. Methods: To determine the level of CE activity, in 1998, postal questionnaires were sent to all fellows of the Royal Australasian College of Dental Surgeons. The responses were analysed. Results: There was a high reponse rate (90 per cent) but a moderate usable rate (54 per cent). The results show a biphasic distribution between high and low CE activity. The average amount of activity of those involved in CE was 116 hours per year, above the usually accepted minimum of 100 hours/year. Some groups, particularly members of the specialist divisions of oral and maxillofacial surgeons (215 hours) and periodontists (205 hours), have high levels of CE. However, approximately 25 per cent of college fellows reported little or no CE activity. The survey revealed that inactive fellows are more likely to be older and in general practice. Inactive fellows were also tardy in replying to the questionnaire. Conclusion: The high activity CE group needs to be recognised and encouraged to continue. Specific plans to help the low CE activity group should be developed. Although these findings relate directly to the Royal Australasian College of Dental Surgeons, they are presented as they have implications for the dental profession at large.P Sambrook, D Thomson, R Bastiaan and A Gos

Recent advancements in information extraction methodology and hardware for Earth Resources Survey Systems

There are no author-identified significant results in this report