Gaze aversion during social style interactions in autism spectrum disorder and Williams syndrome

During face-to-face interactions typically developing individuals use gaze aversion (GA), away from their questioner, when thinking. GA is also used when individuals with autism (ASD) and Williams syndrome (WS) are thinking during question-answer interactions. We investigated GA strategies during face-to-face social style interactions with familiar and unfamiliar interlocutors. Participants with WS and ASD used overall typical amounts/patterns of GA with all participants looking away most while thinking and remembering (in contrast to listening and speaking). However there were a couple of specific disorder related differences: participants with WS looked away less when thinking and interacting with unfamiliar interlocutors; in typical development and WS familiarity was associated with reduced gaze aversion, however no such difference was evident in ASD. Results inform typical/atypical social and cognitive phenotypes. We conclude that gaze aversion serves some common functions in typical and atypical development in terms of managing the cognitive and social load of interactions. There are some specific idiosyncracies associated with managing familiarity in ASD and WS with elevated sociability with unfamiliar others in WS and a lack of differentiation to interlocutor familiarity in ASD. Regardless of the familiarity of the interlocutor, GA is associated with thinking for typically developing as well as atypically developing groups. Social skills training must take this into account

Hard collinear gluon radiation and multiple scattering in a medium

The energy loss of hard jets produced in the Deep-Inelastic scattering (DIS) off a large nucleus is considered in the collinear limit. In particular, the single gluon emission cross section due to multiple scattering in the medium is calculated. Calculations are carried out in the higher-twist scheme, which is extended to include contributions from multiple transverse scatterings on both the produced quark and the radiated gluon. The leading length enhanced parts of these power suppressed contributions are resummed. Various interferences between such diagrams lead to the Landau-Pomeranchuk-Migdal (LPM) effect. We resum the corrections from an arbitrary number of scatterings and isolate the leading contributions which are suppressed by one extra power of the hard scale $Q^{2}$. All powers of the emitted gluon forward momentum fraction $y$ are retained. We compare our results with the previous calculation of single scattering per emission in the higher-twist scheme as well as with multiple scattering resummations in other schemes. It is found that the leading ($1/Q^2$) contribution to the double differential gluon production cross section, in this approach, is equivalent to that obtained from the single scattering calculation once the transverse momentum of the final quark is integrated out. We comment on the generalization of this formalism to Monte-Carlo routines.Comment: 30 pages, 7 figures, revtex4, typos correcte

Pastures from Space - Application of Satellite-Derived Pasture Predictions Improve the Profitability of Australian Sheep Producers

Pastures from Space, a collaborative program between CSIRO Livestock Industries and the Western Australian state Departments of Agriculture and Land Information, has developed the capacity to measure both the biomass and growth rate of annual pasture in the winter rainfall regions of southern Australia using satellite images (Edirisinghe et al., 2002). Producer groups were set up to pilot test the delivery of satellitederived pasture growth rate (PGR, kg dry matter/hectare.day) and biomass (feed on offer or FOO, kg dry matter/hectare) predictions for paddocks on individual farms in Western Australia. This paper reports on the value to Australian sheep producers of satellite-derived PGR information on pastures

Higher twist jet broadening and classical propagation

The transverse broadening of jets produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. A class of medium enhanced higher twist corrections are re-summed to calculate the transverse momentum distribution of the produced collinear jet. In contrast to previous approaches, resummation of the leading length enhanced higher twist corrections is shown to lead to a two dimensional diffusion equation for the transverse momentum of the propagating jet. Results for the average transverse momentum obtained from this approach are then compared to the broadening expected from a classical Langevin analysis for the propagation of the jet under the action of the fluctuating color Lorentz force inside the nucleons. The set of approximations that lead to identical results from the two approaches are outlined. The relationship between the momentum diffusion constant $D$ and the transport coefficient $\hat{q}$ is explicitly derived.Comment: 17 pages, 6 figures, revtex4, references added, typos corrected, discussion update

The Effects of Acute and Chronic Hypoxia on Cortisol, Glucose and Lactate Concentrations in Different Populations of Three-Spined Stickleback

The response of individuals from three different populations of three-spined sticklebacks to acute and chronic periods of hypoxia (4.4 kPa DO, 2.2 mg l-1) were tested using measures of whole-body (WB) cortisol, glucose and lactate. Although there was no evidence of a neuroendocrine stress response to acute hypoxia, fish from the population least likely to experience hypoxia in their native habitat had the largest response to low oxygen, with significant evidence of anaerobic glycolysis after two hours of hypoxia. However, there was no measurable effect of a more prolonged period (seven days) of hypoxia on any of the fish in this study, suggesting that they acclimated to this low level of oxygen over time. Between-population differences in the analytes tested were observed in the control fish of the acute hypoxia trial, which had been in the laboratory for 16 days. However, these differences were not apparent among the control fish in the chronic exposure groups that had been held in the laboratory for 23 days suggesting that these site-specific trends in physiological status were acclimatory. Overall, the results of this study suggest that local environmental conditions may shape sticklebacks’ general physiological profile as well as influencing their response to hypoxia

Development of gaze aversion as disengagement from visual information

Older children, but not younger children, were found to look away more from the face of an interlocutor when answering difficult as opposed to easy questions. Similar results were found in earlier work with adults, who often avert their gaze during cognitively difficult tasks (A.M. Glenberg, J.L. Schroeder, & D.A. Robertson, 1998). Twenty-five 8-year-olds and 26 5-year-olds answered verbal reasoning and arithmetic questions of varying difficulty. The older children increased gaze aversion from the face of the adult questioner in response to both difficult verbal reasoning questions and difficult arithmetic questions. In contrast, younger children (5-year-olds) responded less consistently to cognitive difficulty. It is concluded that adultlike patterns of gaze aversion in response to cognitive difficulty are certainly acquired by 8 years of age. The implications of appropriate gaze aversion for children’s management of cognitive resources are considered

Photon bremsstrahlung and diffusive broadening of a hard jet

The photon bremsstrahlung rate from a quark jet produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. The leading medium-enhanced higher twist corrections which describe the multiple scattering of the jet in the nucleus are re-summed to all orders of twist. The propagation of the jet in the absence of further radiative energy loss is shown to be governed by a transverse momentum diffusion equation. We compute the final photon spectrum in the limit of soft photons, taking into account the leading and next-to-leading terms in the photon momentum fraction y. In this limit, the photon spectrum in a physical gauge is shown to arise from two interfering sources: one where the initial hard scattering produces an off-shell quark which immediately radiates the photon and then undergoes subsequent soft re-scattering; alternatively the quark is produced on-shell and propagates through the medium until it is driven off-shell by re-scattering and radiates the photon. Our result has a simple formal structure as a product of the photon splitting function, the quark transverse momentum distribution coming from a diffusion equation and a dimensionless factor which encodes the effect of the interferences encountered by the propagating quark over the length of the medium. The destructive nature of such interferences in the small y limit are responsible for the origin of the Landau-Pomeranchuck-Migdal (LPM) effect. Along the way we also discuss possible implications for quark jets in hot nuclear matter.Comment: 24 pages, 3 figures, Revtex

Cognitive demands of face monitoring: Evidence for visuospatial overload

Young children perform difficult communication tasks better face to face than when they cannot see one another (e.g., Doherty-Sneddon & Kent, 1996). However, in recent studies, it was found that children aged 6 and 10 years, describing abstract shapes, showed evidence of face-to-face interference rather than facilitation. For some communication tasks, access to visual signals (such as facial expression and eye gaze) may hinder rather than help children’s communication. In new research we have pursued this interference effect. Five studies are described with adults and 10- and 6-year-old participants. It was found that looking at a face interfered with children’s abilities to listen to descriptions of abstract shapes. Children also performed visuospatial memory tasks worse when they looked at someone’s face prior to responding than when they looked at a visuospatial pattern or at the floor. It was concluded that performance on certain tasks was hindered by monitoring another person’s face. It is suggested that processing of visual communication signals shares certain processing resources with the processing of other visuospatial information

Does environmental enrichment promote recovery from stress in rainbow trout?

The EC Directive on animal experimentation suggests that animals should have enrichment to improve welfare yet relatively little research has been conducted on the impact of enrichment in fish. Studies on zebrafish have been contradictory and other fish species may require species specific enrichments. Salmonids are important experimental models given their relevance to aquaculture and natural ecosystems. This study sought to establish how an enriched environment may promote better welfare in rainbow trout (Oncorhynchus mykiss) enhancing their recovery from invasive procedures. Trout were held individually in either barren or enriched (gravel, plants and an area of cover) conditions and recovery rates after a potentially painful event and a standard stressor were investigated by recording parameters such as behaviour, opercular beat rate and plasma cortisol concentrations. Fish were randomly assigned to one of four treatment groups: Control where the fish were left undisturbed; Sham where fish were anaesthetised but no invasive procedure; Pain where a subcutaneous injection of acetic acid was administered to the frontal lips during anaesthesia; and Stress where fish were subject to one minute of air emersion. Video recordings were made prior to treatment then at 30 minute intervals afterwards to determine whether fish in enriched conditions recovered more rapidly than those in barren tanks. Preliminary analyses suggest that enriched fish may be less stressed thus these findings have important implications for the husbandry and welfare of captive rainbow trout but may also affect the outcome of experimental studies dependent upon whether enrichment was adopted

Dynamical frictional phenomena in an incommensurate two-chain model

Dynamical frictional phenomena are studied theoretically in a two-chain model with incommensurate structure. A perturbation theory with respect to the interchain interaction reveals the contributions from phonons excited in each chain to the kinetic frictional force. The validity of the theory is verified in the case of weak interaction by comparing with numerical simulation. The velocity and the interchain interaction dependences of the lattice structure are also investigated. It is shown that peculiar breaking of analyticity states appear, which is characteristic to the two-chain model. The range of the parameters in which the two-chain model is reduced to the Frenkel-Kontorova model is also discussed.Comment: RevTex, 9 pages, 7 PostScript figures, to appear in Phys. Rev.