Precursor scavenging of the resistive grain-boundary phase in 8 mol% yttria-stabilized zirconia: Effect of trace concentrations of SiO2

The influence that trace concentrations Of SiO2 have on improving grain-boundary conduction via precursor scavenging using additional heat treatment at 1200 degreesC for 40 h before sintering was investigated. At a SiO2-impurity level (SIL) less than or equal to 160 ppm by weight, the grain-boundary resistivity (p(gb)) decreased to 20% of its value, while no improvement in grain-boundary conduction was found at a SIL greater than or equal to 310 ppm. The correlation between the resistance per unit grain-boundary area, p(gb), and average grain size indicated that the inhomogeneous distribution of the siliceous phase in the sample with a SIL greater than or equal to 310 ppm. hampered the scavenging reaction.

User's Views of an Outreaching Social Work Team in Hong Kong

This article reports the survey findings of a recent study on users’ views of the service provided by an outreaching social work team in Hong Kong. It attempts to explore how youth at risk can be jointly involved in evaluating the quality of the social service. Users appear to have favourable opinions towards the service received and would like to have greater involvement in programme planning, implementation and evaluation. Finally, recommendations on improving the understanding of the needs of users and encouraging greater user participation in future service delivery are suggested.

Appraisal ratings, halo, and selection: A study using sales staff

Supervisor ratings are useful criteria for the validation of selection instruments but maybe limited because of the presence of rating errors, such as halo. This study set out to show that supervisor ratings which are high in halo remain successful criteria in selection. Following a thorough job analysis, a customer service questionnaire was designed to assess the potential of retail sales staff on three orthogonal subscales labelled Dealing with people, Emotions and energy, and Solitary style. These subscales were uncorrelated with supervisor ratings made about 8 weeks later. However, the supervisor ratings were correlated with an overall scale derived from the three scales of the customer service questionnaire. These results support the view that supervisor ratings generally consist of global impressions and suggest that these global impressions are useful measures of overall performances. This field study confirms laboratory results that halo does not necessarily reduce rating accuracy.

The influence of age on reproductive performance in the Brown Thornbill

I examined age effects on reproduction in the Brown Thornbill Acanthiza pusilla in Canberra, Australia. I found that the reproductive performance of both males and females improved with age, although only age-related improvement in male performance had a significant effect on annual reproductive success. Reproductive success improved with male age as a result of improved performance during two stages of the breeding cycle: first-year males were less likely to fledge young than those aged two or more, while both first and second-year males were less successful at raising fledglings to independence than males of three or more. Male performance appears to improve over three years as they gain experience at provisioning nestlings and caring for fledglings without attracting predators, rather than as a direct result of improved foraging skills. In contrast, reproductive success only improved slightly with female age, although females of two or more years initiated their first clutch earlier in the season than one-year-old females, and tended to be mure likely to re-nest if a breeding attempt failed. The poor performance of young females appears unlikely to be related to their foraging ability but may be associated with costs imposed by dispersing to a breeding vacancy earlier in the year. Although the reproductive performance of Brown Thornbills improves considerably with age 1 found no evidence that performance improved as a result of repeated breeding attempts with the same partner.

An investigation into the interference rejection capability of a linear array in a wireless communications system

The suitable use of an array antenna at the base station of a wireless communications system can result in improvement in the signal-to-interference ratio (SIR). In general, the SIR is a function of the direction of arrival of the desired signal and depends on the configuration of the array, the number of elements, and their spacing. In this paper, we consider a uniform linear array antenna and study the effect of varying the number of its elements and inter-element spacing on the SIR performance. (C) 2002 Wiley Periodicals, Inc.

Interference rejection capabilities of different types of array antennas in cellular systems

The suitable use of array antennas in cellular systems results in improvement in the signal-to-interference ratio (StR), This property is the basis for introducing smart or adaptive antenna systems. in general, the SIR depends on the array configuration and is a function of the direction of the desired user and interferers. Here, the SIR performance for linear and circular arrays is analysed and compared.

On the importance function in splitting simulation

The splitting method is a simulation technique for the estimation of very small probabilities. In this technique, the sample paths are split into multiple copies, at various stages in the simulation. Of vital importance to the efficiency of the method is the Importance Function (IF). This function governs the placement of the thresholds or surfaces at which the paths are split. We derive a characterisation of the optimal IF and show that for multi-dimensional models the natural choice for the IF is usually not optimal. We also show how nearly optimal splitting surfaces can be derived or simulated using reverse time analysis. Our numerical experiments illustrate that by using the optimal IF, one can obtain a significant improvement in simulation efficiency.

Substance misuse in patients with schizophrenia: epidemiology and management

Substance misuse in individuals with schizophrenia is very common, especially in young men, in communities where use is frequent and in people receiving inpatient treatment. Problematic use occurs at very low intake levels, so that most affected people are not physically dependent (with the exception of nicotine). People with schizophrenia and substance misuse have poorer symptomatic and functional outcomes than those with schizophrenia alone. Unless there is routine screening, substance misuse is often missed in assessments. Service systems tend to be separated, with poor inter-communication, and affected patients are often excluded from services because of their comorbidity. However, effective management of these disorders requires a fully integrated approach because of the close inter-relationship of the disorders. Use of atypical antipsychotics may be especially important in this population because of growing evidence (especially on clozapine and risperidone) that nicotine smoking, alcohol misuse and possibly some other substance misuse is reduced. Several pharmacotherapies for substance misuse can be used safely in people with schizophrenia, but the evidence base is small and guidelines for their use are necessarily derived from experience in the general population.

Planning for institutional capacity building in war-torn areas: the case of Jaffna, Sri Lanka

This paper examines an attempt to build capacity and empower local institutions in war-torn Jaffna,, on the northern tip of Sri Lanka. A participatory approach that is aimed at social empowerment is seen to be possible even under the most restrictive of political environments. However, whether or not the development intervention provides a foundation for longer-term improvement depends on the extent to which institutional capacity is built. Through an examination of the Jaffna Reconstruction Project, it is argued that if any of the ingredients of this institutional capacity are missing, not only will the 'islands of participation and empowerment' that are built by the development initiative be short-lived, but there may also be a negligible contribution to building a foundation for longer-term improvement in quality of life. (C) 2001 Elsevier Science Ltd. All rights reserved.

Macrolides in cystic fibrosis. Is there a role?

A spectrum of anti-inflammatory properties, evidence of anti-infective action against Pseudomonas aeruginosa at sub-inhibitory concentrations and positive clinical experience in patients with diffuse panbronchiolitis, a disease with features in common with cystic fibrosis (CF), has prompted research to evaluate the role of macrolide therapy in patients with CF. Newer macrolides such as azithromycin have the advantage of improved tolerability and a prolonged intracellular half-life requiring an infrequent dosing regimen. Results from initial studies suggest a benefit from several months of macrolide therapy in patients with CF. An improvement in lung function was initially shown in a small open study in children, while maintenance of lung function compared with placebo, reduced acute respiratory exacerbations, and reduced systemic markers of inflammation were demonstrated in a randomized, placebo-controlled study of macrolide therapy in adult patients with CF. Additional controlled studies are required to determine optimal drug, dosage, and duration of therapy, and long-term adverse effects of prolonged therapy with macrolides in patients with CF. The potential, with long-term use, to induce resistance against other bacteria colonizing the upper respiratory tract e.g. pneumococci has not been explored. Measurement of cytokines and inflammatory mediators from the sputum of patients with CF is technically difficult and does not correlate with disease activity. There is a need for easily measurable, reproducible and clinically meaningful end-points for evaluation of new therapies in CF. The choice of appropriate outcome measures, apart from lung function, to monitor disease activity needs careful consideration in clinical trials determining the efficacy of macrolides in patients with CF. Evidence-based recommendations for the use of macrolides in the treatment of CF are not expected for some years although macrolides are already being prescribed for long-term use in some centers. There is a need for further research into mechanisms of anti-inflammatory action of macrolides in the lungs of patients with CF and whether or not such therapy may be beneficial in the long term. Copyright 2002 Adis International

Dietary chromium tripicolinate supplementation reduces glucose concentrations and improves glucose tolerance in normal-weight cats

The effect of dietary chromium supplementation on glucose and insulin metabolism in healthy, non-obese cats was evaluated. Thirty-two cats were randomly divided into four groups and fed experimental diets consisting of a standard diet with 0 ppb (control), 150 ppb, 300 ppb, or 600 ppb added chromium as chromium tripicolinate. Intravenous glucose tolerance, insulin tolerance and insulin sensitivity tests with minimal model analysis were performed before and after 6 weeks of feeding the test diets. During the glucose tolerance test, glucose concentrations, area under the glucose concentration-time curve, and glucose half-life (300 ppb only), were significantly lower after the trial in cats supplemented with 300 ppb and 600 ppb chromium, compared with values before the trial. Fasting glucose concentrations measured on a different day in the biochemistry profile were also significantly lower after supplementation with 600 ppb chromium. There were no significant differences in insulin concentrations or indices in either the glucose or insulin tolerance tests following chromium supplementation, nor were there any differences between groups before or after the dietary trial. Importantly, this study has shown a small but significant, dose-dependent improvement in glucose tolerance in healthy, non-obese cats supplemented with dietary chromium. Further long-term studies are warranted to determine if the addition of chromium to feline diets is advantageous. Cats most likely to benefit are those with glucose intolerance and insulin resistance from lack of exercise, obesity and old age. Healthy cats at risk of glucose intolerance and diabetes from underlying low insulin sensitivity or genetic factors may also benefit from long-term chromium supplementation. (C) 2002 ESFM and AAFP.

Using crop simulation to generate genotype by environment interaction effects for sorghum in water-limited environments

Multi-environment trials (METs) used to evaluate breeding lines vary in the number of years that they sample. We used a cropping systems model to simulate the target population of environments (TPE) for 6 locations over 108 years for 54 'near-isolines' of sorghum in north-eastern Australia. For a single reference genotype, each of 547 trials was clustered into 1 of 3 'drought environment types' (DETs) based on a seasonal water stress index. Within sequential METs of 2 years duration, the frequencies of these drought patterns often differed substantially from those derived for the entire TPE. This was reflected in variation in the mean yield of the reference genotype. For the TPE and for 2-year METs, restricted maximum likelihood methods were used to estimate components of genotypic and genotype by environment variance. These also varied substantially, although not in direct correlation with frequency of occurrence of different DETs over a 2-year period. Combined analysis over different numbers of seasons demonstrated the expected improvement in the correlation between MET estimates of genotype performance and the overall genotype averages as the number of seasons in the MET was increased.

Effect of Rosiglitazone on Insulin Sensitivity and Body Composition in Type 2 Diabetic Patients

Objective: To investigate the effects of rosiglitazone (RSG) on insulin sensitivity and regional adiposity (including intrahepatic fat) in patients with type 2 diabetes. Research Methods and Procedures: We examined the effect of RSG (8 mg/day, 2 divided doses) compared with placebo on insulin sensitivity and body composition in 33 type 2 diabetic patients. Measurements of insulin sensitivity (euglycemic hyperinsulinemic clamp), body fat (abdominal magnetic resonance imaging and DXA), and liver fat (magnetic resonance spectroscopy) were taken at baseline and repeated after 16 weeks of treatment. Results: There was a significant improvement in glycemic control (glycosylated hemoglobin -0.7 +/- 0.7%, p less than or equal to 0.05) and an 86% increase in insulin sensitivity in the RSG group (glucose-disposal rate change from baseline: 17.5 +/- 14.5 mumol glucose/min/kg free fat mass, P < 0.05), but no significant change in the placebo group compared with baseline. Total body weight and fat mass increased (p &LE; 0.05) with RSG (2.1 +/- 2.0 kg and 1.4 +/- 1.6 kg, respectively) with 95% of the increase in adiposity occurring in nonabdominal regions. In the abdominal region, RSG increased subcutaneous fat area by 8% (25.0 +/- 28.7 cm(2), p = 0.02), did not alter intra-abdominal fat area, and reduced intrahepatic fat levels by 45% (-6.7 +/- 9.7%, concentration relative to water). Discussion: Our data indicate that RSG greatly improves insulin sensitivity in patients with type 2 diabetes and is associated with an increase in adiposity in subcutaneous but not visceral body regions.

Effect of manual hyperinflation on hemodynamics, gas exchange, and respiratory mechanics in ventilated patients

The authors investigated the effect of manual hyperinflation (MHI) with set parameters applied to patients on mechanical ventilation on hemodynamics, respiratory mechanics, and gas exchange. Sixteen critically ill patients post-septic shock, with acute lung injury, were studied. Heart rate, arterial pressure, and mean pulmonary artery pressure were recorded every minute. pulmonary artery occlusion pressure, cardiac output, arterial blood gases, and dynamic compliance (C-dyn) were recorded pre- and post-MHI. From this, systemic vascular resistance index (SVRI), cardiac index, oxygen delivery, and partial pressure of oxygen:fraction of inspired oxygen (PaO2:FiO(2)) ratio were calculated. There were significant increases in SVRI (P < 0.05) post-MHI and diastolic arterial pressure (P < 0.01)during MHI. C-dyn increased post-MHI (P < 0.01) and was sustained at 20 minutes post-MHI (P < 0.01). Subjects with an intrapulmonary cause of lung disease had a significant decrease (P = 0.02) in PaO2:FiO(2), and those with extrapulmonary causes of lung disease had a significant increase (P < 0.001) in PaO2:FiO(2) post-MHI. In critically ill patients, MHI resulted in an improvement in lung mechanics and an improvement in gas exchange in patients with lung disease due to extrapulmonary events and did not result in impairment of the cardiovascular system.

Mathematical modelling of schistosomiasis japonica: comparison of control strategies in the People's Republic of China

We present the first mathematical model on the transmission dynamics of Schistosoma japonicum. The work extends Barbour's classic model of schistosome transmission. It allows for the mammalian host heterogeneity characteristic of the S. japonicum life cycle, and solves the problem of under-specification of Barbour's model by the use of Chinese data we are collecting on human-bovine transmission in the Poyang Lake area of Jiangxi Province in China. The model predicts that in the lake/marshland areas of the Yangtze River basin: (1) once-early mass chemotherapy of humans is little better than twice-yearly mass chemotherapy in reducing human prevalence. Depending on the heterogeneity of prevalence within the population, targeted treatment of high prevalence groups, with lower overall coverage, can be more effective than mass treatment with higher overall coverage. Treatment confers a short term benefit only, with prevalence rising to endemic levels once chemotherapy programs are stopped (2) depending on the relative contributions of bovines and humans, bovine treatment can benefit humans almost as much as human treatment. Like human treatment, bovine treatment confers a short-term benefit. A combination of human and bovine treatment will dramatically reduce human prevalence and maintains the reduction for a longer period of time than treatment of a single host, although human prevalence rises once treatment ceases; (3) assuming 75% coverage of bovines, a bovine vaccine which acts on worm fecundity must have about 75% efficacy to reduce the reproduction rate below one and ensure mid-term reduction and long-term elimination of the parasite. Such a vaccination program should be accompanied by an initial period of human treatment to instigate a short-term reduction in prevalence, following which the reduction is enhanced by vaccine effects; (4) if the bovine vaccine is only 45% efficacious (the level of current prototype vaccines) it will lower the endemic prevalence, but will not result in elimination. If it is accompanied by an initial period of human treatment and by a 45% improvement in human sanitation or a 30% reduction in contaminated water contact by humans, elimination is then possible. (C) 2002 Elsevier Science B.V. All rights reserved.