The relationship of a clonal outbreak of Enterococcus faecium vanA to methicillin-resistant Staphylococcus aureus incidence in an Australian hospital

Australian isolates of vancomycin-resistant enterococci (VRE) have been widely scattered geographically, predominantly polyclonal and of the VanB phenotype. Forty-nine VRE were isolated from 47 patients in our hospital from October 1996 to December 1999. Forty-four of these VRE were Enterococcus faecium with a vanA glycopeptide resistance genotype. Four isolates were pathogenic. Thirty-five VRE were from an outbreak in the Renal and Infectious Diseases Units over a four-month period. Pulsed-field gel electrophoresis (PFGE) demonstrated that 41 of the 49 VRE were indistinguishable or closely related. Enhanced environmental cleaning, strict contact isolation of colonized patients and reducing inpatient admissions terminated the epidemic. Cohorting of methicillin-resistant Staphylococcus aureus (MRSA)-positive patients was restricted because VPE patients occupied the isolation facilities. This resulted in a statistically significant increase in MRSA infections across the hospital. VRE epidemics have the ability to influence the epidemiology of other nosocomial pathogens when infection control resources are exhausted. (C) 2001 The Hospital Infection Society.

Japanese encephalitis on Badu Island, Australia: the first isolation of Japanese encephalitis virus from Culex gelidus in the Australasian region and the role of mosquito host-feeding patterns in virus transmission cycles

During investigation of an outbreak of Japanese encephalitis (JE) in the Torres Strait, Australia, in 2000, mosquitoes were collected in Badu Island community and at a newly established communal piggery about 3 km from the community. A total of 94285 mosquitoes, comprising 91240 (96.8%) unengorged females, 1630 (1.7%) blood-engorged females and 1415 (1.5%) males, were processed for virus isolation. One isolate of JE virus was obtained from Culex gelidus, with a minimum infection rate of 12.4:1000. This is the first isolate of JE virus from Cx. gelidus in the Australasian region. No isolates were obtained from Cx. annulirostris, the primary implicated Australian JE vector. Analysis of mosquito host-feeding patterns, using gel diffusion, demonstrated that Cx. annulirostris and 5 other species fed predominately on mammals, Analysis of blood-fed mosquitoes collected within the community demonstrated that the proportion of Cx. annulirostris feeding on pigs in 2000 (2.3%) was significantly lower than that for the 1995-97 period (31.3%). The removal of the pigs from Badu Island community has limited the contact between potential amplifying hosts and mosquitoes, thus potentially reducing the risk of transmission of JE virus to the human population.

Flexural waves transmitted by rectangular piezoceramic transducers

Rectangular piezoceramic transducers are widely used in ultrasonic evaluation and health monitoring techniques and structural vibration control applications. In this paper the flexural waves excited by rectangular transducers adhesively attached to isotropic plates are investigated. In view of the difficulties in developing accurate analytical models describing the transfer characteristics of the transducer due to the complex electromechanical transduction processes and transducer-structure interactions involved, a combined theoretical-experimental approach is developed. A multiple integral transform method is used to describe the propagation behaviour of the waves in the plates, while a heterodyne Doppler laser vibrometer is employed as a non-contact receiver device. This combined theoretical-experimental approach enables the efficient characterization of the electromechanical transfer properties of the piezoelectric transducer which is essential for the development of optimized non-destructive evaluation systems. The results show that the assumption of a uniform contact pressure distribution between the transducer and the plate can accurately predict the frequency spectrum and time domain response signals of the propagating waves along the main axes of the rectangular transmitter element.

Life on the ocean wave: Testing some intergroup hypotheses in a naturalistic setting

A survey (N= 352) was conducted among British passengers of a cross-channel ferry. The survey aimed to test hypotheses drawn from Realistic Group Conflict, Social Identity and Contact theories using mainly a correlational design. However, an intervention by members of the outgroup (French fishermen blockading a port) also allowed a quasi-experimental test of the effects of a direct experience of intergroup conflict. Results supported the hypotheses since conflict and national identification were associated with more negative and with less positive attitudes toward the outgroup, while contact had the reverse effects. In addition, the salience of group membership in the contact relationship weakly moderated the effect of contact.

"They're scared of it": Intergroup determinants of attitudes toward children with HIV

The study used an intergroup perspective to explore teachers' willingness to teach children with HIV within mainstream education. One hundred thirty-eight teachers from 13 high schools across the United Kingdom participated in a survey. The results suggest that previous contact with an individual who was HIV positive (whether an adult or a child) was strongly associated with greater willingness to teach a child with HIV. However, this effect disappeared when intergroup anxiety, positive affect, and positive beliefs were included as covariates. There was little evidence that instrumental variables (i.e., relatively pragmatic concerns about infection) were associated with willingness to teach. Participants who had some contact reported lower fear of contagion from a child with HIV, but there was no evidence that this was associated with overall attitudes. The results are interpreted to suggest that interventions to reduce prejudice should not simply concentrate on improving knowledge about HIV transmission.

A novel approach to antigen-specific deletion of CTL with minimal cellular activation using alpha 3 domain mutants of MHC class I/peptide complex

In this study, we have compared the effector functions and fate of a number of human CTL clones in vitro or ex vivo following contact with variant peptides presented either on the cell surface or in a soluble multimeric format. In the presence of CD8 coreceptor binding, there is a good correlation between TCR signaling, killing of the targets, and Fast-mediated CTL apoptosis. Blocking CD8 binding using (alpha3 domain mutants of MHC class I results in much reduced signaling and reduced killing of the targets. Surprisingly, however, Fast expression is induced to a similar degree on these CTLs, and apoptosis of CTL is unaffected. The ability to divorce these events may allow the deletion of antigen-specific and pathological CTL populations without the deleterious effects induced by full CTL activation.

Occupational Therapy in mental health: Managing stress and burnout

Stress and burnout for human service workers has received increasing attention over a number of years. It has been suggested that health care professionals may be particularly at risk of stress and burnout because of the amount and type of direct client contact that makes up their work. For workers in the field of mental health, additional stressors are present owing to organisational restructuring and new models of care. Mental health occupational therapists may be vulnerable to stress and burnout owing to the nature of their work, the types of client they see, the changed work environment and professional issues. It is recommended that occupational therapists become aware of the factors contributing to stress and burnout and develop strategies to maintain their wellbeing in the workforce.

Employee adjustment to an organizational merger: An intergroup perspective

Adopting an intergroup perspective, the research was designed to examine predictors of employee responses to an organizational merger Data were collected from 465 fleet staff employed in a newly merged airline company. As predicted from social identity theory, the negative effects of the merger were most marked for employees of the low-status premerger organization. Also, as predicted, the perception of permeable intergroup boundaries in the new organization was associated positively with identification with the new organization and both job-related and person-related outcomes among employees of the low-status premerger organization but negatively with person-related outcomes among employees of the high-status premerger organization. As predicted, there was some evidence that the main and interactive effects involving status, perceived permeability, and intergroup contact on employee adjustment were mediated through strength of identification with the new organization.

Myth, moment and the challenge of identities: Stories from Australians of Indigenous and Chinese ancestry

There has been a long history of contact between Indigenous and Chinese people in north-eastern Australia. This is evidenced in contemporary communities by the significant presence of mixed-heritage individuals of Indigenous and Chinese ancestry. This paper employs the stories of 10 such individuals to examine their incorporation of 'otherculture' ancestries into identity constructs. In doing so, the paper sheds light on how identities are narrated at the intersection of 'myth' and 'moment', and how challenge evokes transformation and discontinuity. Three broad identity responses emerge from the data: affirmation of singular constructs; questioning and contemplation; and pluralist embracing of both cultures. Historical and contemporary discourses feature prominently, covertly and overtly restricting potential identifications. Mutuality and hegemonic rivalry are found to underpin the narration of relations between the two marginalised and racialised groups.

Haptic information stabilizes and destabilizes coordination dynamics

Goal-directed, coordinated movements in humans emerge from a variety of constraints that range from 'high-level' cognitive strategies based oil perception of the task to 'low-level' neuromuscular-skeletal factors such as differential contributions to coordination from flexor and extensor muscles. There has been a tendency in the literature to dichotomize these sources of constraint, favouring one or the other rather than recognizing and understanding their mutual interplay. In this experiment, subjects were required to coordinate rhythmic flexion and extension movements with an auditory metronome, the rate of which was systematically increased. When subjects started in extension on the beat of the metronome, there was a small tendency to switch to flexion at higher rates, but not vice versa. When subjects: were asked to contact a physical stop, the location of which was either coincident with or counterphase to the auditor) stimulus, two effects occurred. When haptic contact was coincident with sound, coordination was stabilized for both flexion and extension. When haptic contact was counterphase to the metronome, coordination was actually destabilized, with transitions occurring from both extension to flexion on the beat and from flexion to extension on the beat. These results reveal the complementary nature of strategic and neuromuscular factors in sensorimotor coordination. They also suggest the presence of a multimodal neural integration process-which is parametrizable by rate and context - in which intentional movement, touch and sound are bound into a single, coherent unit.

The effect of obstacle position on reach-to-grasp movements

Numerous everyday tasks require the nervous system to program a prehensile movement towards a target object positioned in a cluttered environment. Adult humans are extremely proficient in avoiding contact with any non-target objects (obstacles) whilst carrying out such movements. A number of recent studies have highlighted the importance of considering the control of reach-to-grasp (prehension) movements in the presence of such obstacles. The current study was constructed with the aim of beginning the task of studying the relative impact on prehension as the position of obstacles is varied within the workspace. The experimental design ensured that the obstacles were positioned within the workspace in locations where they did not interfere physically with the path taken by the hand when no obstacle was present. In all positions, the presence of an obstacle caused the hand to slow down and the maximum grip aperture to decrease. Nonetheless, the effect of the obstacle varied according to its position within the workspace. In the situation where an obstacle was located a small distance to the right of a target object, the obstacle showed a large effect on maximum grip aperture but a relatively small effect on movement time. In contrast, an object positioned in front and to the right of a target object had a large effect on movement speed but a relatively small effect on maximum grip aperture. It was found that the presence of two obstacles caused the system to decrease further the movement speed and maximum grip aperture. The position of the two obstacles dictated the extent to which their presence affected the movement parameters. These results show that the antic ipated likelihood of a collision with potential obstacles affects the planning of movement duration and maximum grip aperture in prehension.

Distributed laser refrigeration

A 250-mum-diameter fiber of ytterbium-doped ZBLAN (fluorine combined with Zr, Ba, La, Al, and Na) has been cooled from room temperature. We coupled 1.0 W of laser light from a 1013-nm diode laser into the fiber. We measured the temperature of the fiber by using both fluorescence techniques and a microthermocouple. These microthermocouple measurements show that the cooled fiber can be used to refrigerate materials brought into contact with it. This, in conjunction with the use of a diode laser as the light source, demonstrates that practical solid-state laser coolers can be realized. (C) 2001 Optical Society of America.

FAM deubiquitylating enzyme is essential for preimplantation mouse embryo development

FAM is a developmentally regulated substrate-specific deubiquitylating enzyme. It binds the cell adhesion and signalling molecules beta -catenin and A-F-6 in vitro, and stabilises both in mammalian cell culture. To determine if FAM is required at the earliest stages of mouse development we examined its expression and function in preimplantation mouse embryos. FAM is expressed at all stages of preimplantation development from ovulation to implantation. Exposure of two-cell embryos to FAM-specific antisense, but not sense, oligodeoxynucleotides resulted in depletion of the FAM protein and failure Of the embryos to develop to blastocysts. Loss of FAM had two physiological effects, namely, a decrease in cleavage rate and an inhibition of cell adhesive events. Depletion of FAM protein was mirrored by a loss of beta -catenin such that very little of either protein remained following 72 h culture. The residual beta -catenin was localised to sites of cell-cell contact suggesting that the cytoplasmic pool of beta -catenin is stabilised by FAM. Although AF-6 levels initially decreased they returned to normal. However, the nascent protein was mislocalised at the apical surface of blastomeres. Therefore FAM is required for preimplantation mouse embryo development and regulates beta -catenin and AF-6 in vivo. (C) 2001 Elsevier Science Ireland Lid. All rights reserved.

Dynamics of a mesoscopic charge quantum bit under continuous quantum measurement

We present the conditional quantum dynamics of an electron tunneling between two quantum dots subject to a measurement using a low transparency point contact or tunnel junction. The double dot system forms a single qubit and the measurement corresponds to a continuous in time readout of the occupancy of the quantum dot. We illustrate the difference between conditional and unconditional dynamics of the qubit. The conditional dynamics is discussed in two regimes depending on the rate of tunneling through the point contact: quantum jumps, in which individual electron tunneling current events can be distinguished, and a diffusive dynamics in which individual events are ignored, and the time-averaged current is considered as a continuous diffusive variable. We include the effect of inefficient measurement and the influence of the relative phase between the two tunneling amplitudes of the double dot/point contact system.