Theory of mind and central coherence in adults with high-functioning autism or Asperger syndrome

The study investigated theory of mind and central coherence abilities in adults with high-functioning autism (HFA) or Asperger syndrome (AS) using naturalistic tasks. Twenty adults with HTA/AS correctly answered significantly fewer theory of mind questions than 20 controls on a forced-choice response task. On a narrative task, there were no differences in the proportion of mental state words between the two groups, although the participants with HFA/AS were less inclined to provide explanations for characters' mental states. No between-group differences existed on the central coherence questions of the forced-choice response task, and the participants with HTA/AS included an equivalent proportion of explanations for non-mental state phenomena in their narratives as did controls. These results support the theory of mind deficit account of autism spectrum disorders, and suggest that difficulties in mental state attribution cannot be exclusively attributed to weak central coherence.

Numerical simulation of double-diffusion driven convective flow and rock alteration in three-dimensional fluid-saturated geological fault zones

Numerical methods are used to simulate the double-diffusion driven convective pore-fluid flow and rock alteration in three-dimensional fluid-saturated geological fault zones. The double diffusion is caused by a combination of both the positive upward temperature gradient and the positive downward salinity concentration gradient within a three-dimensional fluid-saturated geological fault zone, which is assumed to be more permeable than its surrounding rocks. In order to ensure the physical meaningfulness of the obtained numerical solutions, the numerical method used in this study is validated by a benchmark problem, for which the analytical solution to the critical Rayleigh number of the system is available. The theoretical value of the critical Rayleigh number of a three-dimensional fluid-saturated geological fault zone system can be used to judge whether or not the double-diffusion driven convective pore-fluid flow can take place within the system. After the possibility of triggering the double-diffusion driven convective pore-fluid flow is theoretically validated for the numerical model of a three-dimensional fluid-saturated geological fault zone system, the corresponding numerical solutions for the convective flow and temperature are directly coupled with a geochemical system. Through the numerical simulation of the coupled system between the convective fluid flow, heat transfer, mass transport and chemical reactions, we have investigated the effect of the double-diffusion driven convective pore-fluid flow on the rock alteration, which is the direct consequence of mineral redistribution due to its dissolution, transportation and precipitation, within the three-dimensional fluid-saturated geological fault zone system. (c) 2005 Elsevier B.V. All rights reserved.

Spatial memory and orientation strategies in the elasmobranch Potamotrygon motoro

We investigated whether juvenile freshwater stingrays (Potamotrygon motoro) can solve spatial tasks by constructing a cognitive map of their environment. Two experimental conditions were run: allocentric and ego-allocentric. Rays were trained to locate food within a four-arm maze placed in a room with visual spatial cues. The feeding location (goal) within the maze (room) remained constant while the starting position varied for the allocentrically but not for the ego-allocentrically trained group. After training, all rays solved the experimental tasks; however, different orientation strategies were used within and between groups. Allocentrically trained rays reached the goal via novel routes starting from unfamiliar locations, while ego-allocentrically trained rays primarily solved the task on the basis of an egocentric turn response. Our data suggest that P. motoro orients by constructing a visual cognitive map of its environment, but also uses egocentric and/or other orientation strategies alone or in combination for spatial orientation, a choice which may be governed by the complexity of the problem. We conclude that spatial memory functions are a general feature of the vertebrate brain.

Opposing roles for medial and central amygdala in the initiation of noradrenergic cell responses to a psychological stressor

Psychological stressors trigger the activation of medullary noradrenergic cells, an effect that has been shown to depend upon yet-to-be-identified structures located higher in the brain. To test whether the amygdala is important in this regard, we examined the effects of amygdala lesions on noradrenergic cell responses to restraint, and also looked at whether any amygdala cells that respond to restraint project directly to the medulla. Ibotenic acid lesions of the medial amygdala completely abolished restraint-induced Fos expression in A1 and A2 noradrenergic cells. In contrast, lesions of the central amygdala actually facilitated noradrenergic cell responses to restraint. Tracer deposits in the dorsomedial (but not ventrolateral) medulla retrogradely labelled many cells in the central nucleus of the amygdala, but none of these cells expressed Fos in response to restraint. These data suggest for the first time that the medial amygdala is critical to the activation of medullary noradrenergic cells by a psychological stressor whereas the central nucleus exerts an opposing, inhibitory influence upon noradrenergic cell recruitment. The initiation of noradrenergic cell responses by the medial amygdala does not involve a direct projection to the medulla. Accordingly, a relay through some other structure, such as the hypothalamic paraventricular nucleus, warrants careful consideration.

Birth-death processes with disaster and instantaneous resurrection

A new structure with the special property that instantaneous resurrection and mass disaster are imposed on an ordinary birth-death process is considered. Under the condition that the underlying birth-death process is exit or bilateral, we are able to give easily checked existence criteria for such Markov processes. A very simple uniqueness criterion is also established. All honest processes are explicitly constructed. Ergodicity properties for these processes are investigated. Surprisingly, it can be proved that all the honest processes are not only recurrent but also ergodic without imposing any extra conditions. Equilibrium distributions are then established. Symmetry and reversibility of such processes are also investigated. Several examples are provided to illustrate our results.

Markers associated with stalk number and suckering in sugarcane colocate with tillering and rhizomatousness QTLs in sorghum

Two important factors influencing sugar yield, the primary focus of sugarcane plant breeding programs, are stalk number and suckering. Molecular markers linked to both of these traits are sought to assist in the identification of high sugar yield, high stalk number, low-suckering sugarcane clones. In this preliminary mapping study, 108 progeny from a biparental cross involving two elite Australian sugarcane clones were evaluated at two sites for two years for both stalk number and suckering. A total of 258 DNA markers, including both restriction fragment length polymorphisms (RFLPs) and radio-labelled amplified fragments (RAFs), were scored and evaluated using single-factor analysis. Sixteen (7 RFLPs and 9 RAFs) and 14 (6 RFLPs and 8 RAFs) markers were identified that were significantly associated (P < 0.01) with stalk number and suckering, respectively, across both years and sites. The seven and six RFLP markers associated with stalk number and suckering, respectively, were generated by eight different RFLP probes, of which seven had been mapped in sorghum and (or) sugarcane. Of significant interest was the observation that all seven RFLP probes could be shown to be located within or near QTLs associated with tillering and rhizomatousness in sorghum. This observation highlights the usefulness of comparative mapping between sorghum and sugarcane and suggests that the identification of useful markers for stalk number and suckering in sugarcane would be facilitated by focussing on sorghum QTLs associated with related traits.

Impaired memory and olfactory performance in NaSi-1 sulphate transporter deficient mice

In the present study, NaSi-l sulphate transporter knock-out (Nas1-/-) mice, an animal model of hyposulphataernia, were examined for spatial memory and learning in a Morris water maze, and for olfactory function in a cookie test. The Nas1-/- mice displayed significantly (P < 0.05) increased latencies to find an escape platform in the reversal teaming trials at 2 days but not 1 day after the last acquisition trial in a Morris water maze test. suggesting that Nas1-/- mice may have proactive memory interference. While the wild-type (Ncis1+/+) mice showed a significant (P < 0.02) decrease in time to locate a hidden food reward over four trials after overnight fasting, Nas1-/- mice did not change their performance, resulting in significantly (P < 0.05) higher latencies when compared to their Nas1+/+ littermates. There were no significant differences between Nas1-/- and Nas1+/+ mice in the cookie test after moderate food deprivation. In addition, both Nas1-/- and Nas1+/+ mice displayed similar escape latencies in the acquisition phase of the Morris water maze test, suggesting that learning, motivation, vision and motor skills required for the task may not be affected in Nas1-/- mice. This is the first study to demonstrate an impairment in memory and olfactory performance in the hyposulphataemic Nas1-/- mouse. (c) 2004 Elsevier B.V. All rights reserved.

Quantifying stresses and support requirements in the undercut and production level drifts of block and panel caving mines

A numerical modelling strategy has been developed in order to quantify the magnitude of induced stresses at the boundaries of production level and undercut level drifts for various in situ stress environments and undercut scenarios. The results of the stress modelling were in line with qualitative experiential guidelines and a limited number of induced stress measurements documented from caving sites. A number of stress charts were developed which quantify the maximum boundary stresses in drift roofs for varying in situ stress regimes, depths and undercut scenarios. This enabled many of the experiential guidelines to be quantified and bounded. A limited number of case histories of support and support performance in cave mine drifts were compared to support recommendations using the NGI classification system, The stress charts were used to estimate the Stress Reduction Factor for this system. The back-analyses suggested that the NGI classification system might be able to give preliminary estimates of support requirements in caving mines with modifications relating to rock bolt length and the support of production level intersections. (C) 2002 Elsevier Science Ltd. All rights reserved.

X-linked myoclonic epilepsy with spasticity and intellectual disability - Mutation in the homeobox gene ARX

Objective: To describe a new syndrome of X-linked myoclonic epilepsy with generalized spasticity and intellectual disability (XMESID) and identify the gene defect underlying this disorder. Methods: The authors studied a family in which six boys over two generations had intractable seizures using a validated seizure questionnaire, clinical examination, and EEG studies. Previous records and investigations were obtained. Information on seizure disorders was obtained on 271 members of the extended family. Molecular genetic analysis included linkage studies and mutational analysis using a positional candidate gene approach. Results: All six affected boys had myoclonic seizures and TCS; two had infantile spasms, but only one had hypsarrhythmia. EEG studies show diffuse background slowing with slow generalized spike wave activity. All affected boys had moderate to profound intellectual disability. Hyperreflexia was observed in obligate carrier women. A late-onset progressive spastic ataxia in the matriarch raises the possibility of late clinical manifestations in obligate carriers. The disorder was mapped to Xp11.2-22.2 with a maximum lod score of 1.8. As recently reported, a missense mutation (1058C>T/P353L) was identified within the homeodomain of the novel human Aristaless related homeobox gene (ARX). Conclusions: XMESID is a rare X-linked recessive myoclonic epilepsy with spasticity and intellectual disability in boys. Hyperreflexia is found in carrier women. XMESID is associated with a missense mutation in ARX. This disorder is allelic with X-linked infantile spasms (ISSX; MIM 308350) where polyalanine tract expansions are the commonly observed molecular defect. Mutations of ARX are associated with a wide range of phenotypes; functional studies in the future may lend insights to the neurobiology of myoclonic seizures and infantile spasms.

Implications of social capital for the inclusion of people with disabilities and families in community life

This paper seeks to ascertain the usefulness of the theory of social capital as a framework for developing and sustaining the inclusion of people with disabilities and families in community life. We discuss the theoretical elements of social capital and assess its relevance when understanding both the experiences of people with disabilities and their families and the possible implications for policy and programme efforts to promote inclusion. Preliminary findings from two studies of the experiences and social networks of people with disabilities and their families in communities in regional and rural Australia are presented. It is argued that to date, people with disabilities and their families have largely been excluded from the broader social capital debate and that social capital thinking has had minimal influence on efforts to achieve the inclusion of people with disabilities into community life. It is further argued that new paradigms of support are needed that build capacity and social capital through working alongside individuals and families to influence not only outcomes for them, but also for the communities on which they live. The local area coordination model as it has developed in Australia since 1989 provides some instructive signposts for integrating individual, family and community approaches. It is concluded that social capital theory can make a contribution to inclusion theory and practice but we should use it with circumspection.