Search

This paper experimentally evaluates the interference cancellation performance of different adaptive beamforming schemes applicable to high frequency (HF) over-the-horizon (OTH) radar systems. Such systems are known to receive multipath and diffusely scattered radio frequency interference produced as a result of reflection from the stratified, dynamic and spatially inhomogeneous ionospheric propagation medium. Apart from quantifying the effectiveness of operational adaptive beamformers in the HF (3–30 MHz) environment, realistic interference models are described and experimentally evaluated in terms of their ability to predict the observed interference cancellation performance which is not well represented by traditional models. Adaptive beamforming algorithms with robustness against “jammer motion” are also described and their effectiveness is experimentally demonstrated using interference data collected by 32 narrowband receivers of the very wide aperture (2.8 km) Jindalee OTH radar uniform linear array located near Alice Springs in central Australia.

Vancomycin-resistant enterococci (VRE) are increasingly recognised nosocomial pathogens in clinical areas with high antibiotic usage. Patients with chronic renal failure, including those requiring haemodialysis, are at particular risk. Investigation and control of an outbreak of VRE in two renal wards, highlighting mattresses as reservoirs and environmental measures to control VRE are reported in this paper. Outbreak control measures included standard isolation in accordance with the Recommendations of the Hospital Infection Control Practices Advisory Committee (HICPAC). Patients were screened on admission and weekly using a rectal swab. The inanimate environment including mattresses was also screened. Enhanced environmental decontamination was performed on a daily basis.The outbreak continued over a 20-week period with most cases occurring in the first 6 weeks. The results of screening indicated that 59 (13%) of 451 patients and 54 (8.3%) of 647 environmental samples were positive for VRE. VRE was isolated from 35 (8%) of 433 mattresses, 12 (8.1%) of 148 environmental ledges, 4 (8%) of 50 toilets, and 3 (18.8%) of 16 items of cleaning equipment. Molecular typing indicated that a predominant strain was also implicated in mattress contamination, thus highlighting a potential and important reservoir for transmission of VRE. Difficulty with eradication of VRE from the environment was encountered despite enhanced cleaning regimens and a doubling of use of disinfectant was necessary.Restriction of antibiotics, hand hygiene, hygiene and education are the cornerstone of VRE prevention and control. Lessons from this outbreak highlight the role of the environment in VRE transmission and the need for attention to the environment, especially mattress decontamination.

This investigation examined perceived stress levels, personality characteristics and stress outcomes in a group of hospital dentists working in Belfast. Mean scores for this group were also compared with normative values. The occupational stress indicator was distributed to 45 hospital dentists; 40 returned the completed questionnaire. The mean score for each stress-related factor was analysed and compared with normative values. In addition the ranked scores for sources of stress were examined, and no significant differences could be demonstrated between the two groups. However, for external locus of control this group of hospital dentists demonstrated a significantly higher mean score of 42.3 than the mean normative value of 38.6. The dentists' score for their perception of their state of physical ill health was 23.9 and was significantly lower than the normative value of 27.8 but no differences could be demonstrated between the groups for mental health, Type A personality or mean stress levels

Of cancer deaths in New Zealand men prostate cancer is one of the major causes after lung and large bowel. While the majority of NZers are Caucasians of European descent, there are two large populations of Pacific origin-Mäori and Pacific Island people. More Mäori and Pacific Island men die from prostate cancer than NZ European. Ethnicity and diet are linked factors that have been suggested to influence prostate cancer risk. For example, the incidence of prostate cancer in Asian men is significantly lower than in American men. Features of the Asian diet include soy, vegetables, fish and tea, which have all been investigated for possible protective effects. The Western diet is high in meat and saturated fats, and low in fibre, factors that have been associated with increased risk of cancer. Several aspects of red meat have been studied for possible carcinogenic mechanisms, including the fat content and cooking technique used. In our study we aimed to characterise differences in dietary intake between three ethnic groups of New Zealand men- Mäori, NZ European, and Pacific Island; and to examine associations between levels of total Prostate Specific Antigen (PSA) and it's derivatives [complex PSA, free PSA (fPSA), and the ratio of free to total PSA (fPSA)].