Expecting dirt but saying dart: The creation of a blend memory

During a naming task, time pressure and a manipulation of the proportion of related prime-target pairs were used to induce subjects to generate an expectation to the prime. On some trials, the presented target was orthographically and generally phonologically similar to the expected tal-get. The expectancy manipulation was barely detectable in the priming data but was clearly evident on a final recognition test. In addition, the recognition data showed that the nearly simultaneous activation of an expectation and sensory information derived from the orthographically and phonologically similar target produced a false memory. It is argued that this represents a blend memory.

Working memory in schizophrenia and mania: Correlation with symptoms during the acute and subacute phases

Objective: The aims of this study were to examine working memory in the acute-subacute phase of schizophrenia and mania and to examine correlations between working memory and specific symptom domains. Method: Visuospatial working memory and symptom profiles were assessed in three groups (schizophrenia group, n=19; mania, n=12; controls, n=19) on two occasions separated by 4 weeks. Results: Both patient groups had significant deficits on working memory compared to the well controls and the schizophrenia and mania groups were equally impaired. All groups showed equivalent improvement over time. In the patient groups, impaired working memory was significantly correlated with the presence of both negative symptoms and positive thought disorder. Conclusion: Impaired wet-king memory is found in both schizophrenia and mania during the acute-subacute phases. Further research is required in order to clarify the neurocognitive mechanisms linking impaired working memory with both negative symptoms and positive thought disorder.

Functional roles of abdominal and back muscles during isometric axial rotation of the trunk

Electromyographic (EMG) studies have shown that a large number of trunk muscles are recruited during axial rotation. The functional roles of these trunk muscles in axial rotation are multiple and have not been well investigated. In addition, there is no information on the coupling torque at different exertion levels during axial rotation. The aim of the study was to investigate the functional roles of rectus abdominis. external oblique. internal oblique, latissimus dorsi, iliocostalis lumborum and multifidus during isometric right and left axial rotation at 100%, 70%, 50% and 30% maximum voluntary contractions (MVC) in a standing position. The coupling torques in sagittal and coronal planes were measured during axial rotation to examine the coupling nature of torque at different levels of exertions. Results showed that the coupled sagittal torque switches from nil to flexion at maximum exertion of axial rotation. Generally, higher EMG activities were shown at higher exertion levels for all the trunk muscles. Significant differences in activity between the right and left axial rotation exertions were demonstrated in external oblique, internal oblique, latissimus dorsi and iliocostalis lumborum while no difference was shown in rectus abdominis and multifidus. These results demonstrated the different functional roles of trunk muscles during axial rotation. This is important considering that the abdominal and back muscles not only produce torque but also maintain the spinal posture and stability during axial rotation exertions. The changing coupling torque direction in the sagittal plane when submaximal to maximal exertions were compared may indicate the complex nature of the kinetic coupling of trunk muscles. (C) 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.

On a possible mechanism for peripheral nerve stimulation during magnetic resonance imaging scans

When patients undergo a magnetic resonance imaging scan, they are subject to both strong static and temporal magnetic fields. The temporal fields are designed to vary at each point in the region being imaged. This is achieved by the use of gradient coils. However, when the gradient coils are switched very rapidly, the strongly time-varying magnetic fields produced can be responsible for stimulating nerves in the peripheral regions of the body. This paper gives a somewhat novel explanation for this phenomenon. The physical mechanism suggested is supported by an illustrative theoretical calculation.

The nutritive value of Rhodes grass (Chloris gayana) when treated with CaO, NaOH or a microbial inoculant and offered to dairy heifers as big-bale silage

A series of laboratory and animal studies examined the use of chemical and biological agents to enhance the digestibility of Rhodes grass (grass) cut at 60 (young) and 100 (mature) days of regrowth and ensiled as big round bales. The treatments included an untreated control (C), a microbial inoculant (I), NaOH, CaO and NaOH plus inoculant (NaOH + I). Inoculant was grown anaerobically, using a starter culture of rumen fluid from cattle given Rhodes grass. Treatments C, 1, NaOH, NaOH + I, were offered separately to twelve dairy heifers, in a 3 X 4 randomized complete block design, repeated twice for each grass silage. C and I had substantial mould growth, compared with no visible mould in NaOH or NaOH + 1. CaO treatment was effective in preventing mould growth, but had little effect on the chemical composition and in sacco digestibility of mature grass silage. NaOH reduced NDF content and increased in sacco digestibility (P < 0.05) but not the in vivo digestibility (P > 0.05) of both mature- and young-grass silage. The effects of other treatments on nutritive value were non-significant at both stages of maturity. NaOH increased the intake of mature-grass silage by 24-26% (P < 0.05), but had little effect on the intake of young-grass silage (P > 0.05). Treatment I consistently reduced grass silage intake (P < 005) for young-grass silage. The findings of these studies show that treating mature Rhodes grass with NaOH will improve its nutritive value and reduce mould growth in conserved herbage. However none of the treatments in this study had any consistently positive effects on the in vivo nutritive value or storage quality of young-grass silage.

Woodstoves uncovered: a paediatric problem

Objectives: To document and describe the effects of woodstove burns in children. To identify how these accidents occur so that a prevention strategy can be devised. Design, Patients and Setting: Retrospective departmental database and case note review of all children with woodstove burns seen at the Burns Unit of a Tertiary Referral Children's Hospital between January 1997 and September 2001. Main outcome measures: Number and ages of children burned: circumstances of the accidents; injuries-sustained, treatment-required and long-term sequelae. Results. Eleven children, median age 1.0 year, sustained burns, usually to the hands, of varying thickness. Two children required skin grafting and five required scar therapy. Seven children intentionally placed their hands onto the Outside of the stove. In all children, burns occurred despite adult supervision Conclusions: Woodstoves area cause of burns in children. These injuries are associated with significant morbidity and financial costs. Through public education, woodstove burns can easily be prevented utilising simple safety measures. (C) 2002 Elsevier Science Ltd and ISBI All rights reserved.

Genetic sources of covariation among P3(00) and online performance variables in a delayed-response working memory task

Genetic and environmental sources of covariation among the P3(00) and online performance elicited in a delayed-response working memory task, and psychometric IQ assessed by the multidimensional aptitude battery, were examined in an adolescent twin sample. An association between frontal P3 latency and task performance (phenotypic r = -0.33; genotypic r = -0.49) was indicated, with genes (i.e. twin status) accounting for a large part of the covariation ( > 70%). In contrast, genes influencing P3 amplitude mediated only a small part (2%) of the total genetic variation in task performance. While task performance mediated 15% of the total genetic variation in IQ (phenotypic r = 0.22; genotypic r = 0.39) there was no association between P3 latency and IQ or P3 amplitude with IQ. The findings provide some insight into the inter-relationships among psychophysiological, performance and psychometric measures of cognitive ability, and provide support for a levels-of-processing genetic model of cognition where genes act on specific sub-components of cognitive processes.

An inverse design of an open, head/neck RF coil for MRI

Radio-frequency (RF) coils are a necessary component of magnetic resonance imaging (MRI) systems. When used in transmit operation, they act to generate a homogeneous RF magnetic field within a volume of interest and when in receive operation, they act to receive the nuclear magnetic resonance signal from the RF-excited specimen. This paper outlines a procedure for the design of open RF coils using the time-harmonic inverse method. This method entails the calculation of an ideal current density on a multipaned planar surface that would generate a specified magnetic field within the volume of interest. Because of the averaging effect of the regularization technique in the matrix solution, the specified magnetic field is shaped within an iterative procedure until the generated magnetic field matches the desired magnetic field. The stream-function technique is used to ascertain conductor positions and a method of moments package is then used to finalize the design. An open head/neck coil was designed to operate in a clinical 2T MRI system and the presented results prove the efficacy of this design methodology.

Epizootic activity of Murray Valley encephalitis virus in an aboriginal community in the southeast Kimberley region of western Australia: Results of cross-sectional and longitudinal serologic studies

Murray Valley encephalitis (MVE) virus is a mosquito-borne flavivirus causing severe encephalitis with a resultant high morbidity and mortality. In the period 1989-1993. we undertook a cross-sectional and longitudinal studs by annually screening members of a small remote Aboriginal community in northwestern Australia for MVE virus antibodies. Of the estimated 250-300 people in the community. 249 were tested, and 52.6% had positive serology to MVE. The proportion testing positive increased with increasing age group. and males were slightly more likely to be positive than females. During the study period. a high proportion of the population seroconverted to MVE: the clinical/subclinical ratio seems to be lower than previously reported. Although MVE is mostly asymptomatic, the devastating consequences of clinical illness indicate that advice should be provided regarding the avoidance of mosquito bites. Our longitudinal study showed that the risk of seroconversion was similar for each age group. not just the young.