A structural MRI study in monozygotic twins concordant or discordant for attention/hyperactivity problems: Evidence for genetic and environmental heterogeneity in the developing brain.

Several structural brain abnormalities have been reported in patients with Attention Deficit Hyperactivity Disorder (ADHD). However, the etiology of these brain changes is still unclear. To investigate genetic and environmental influences on ADHD related neurobiological changes, we performed Voxel-Based Morphometry on MRI scans from monozygotic (MZ) twins selected from a large longitudinal population database to be highly concordant or highly discordant for ratings on the Child Behavior Checklist Attention Problem scale (CBCL-AP). Children scoring low on the CBCL-AP are at low risk for ADHD, whereas children scoring high on this scale are at high-risk for ADHD. Brain differences between concordant high-risk twin pairs and concordant low-risk twin pairs likely reflect the genetic risk for ADHD; brain differences between the low-risk and high-risk twins from discordant MZ twin pairs reflect the environmental risk for ADHD. A major difference between comparisons of high and low-risk twins from concordant pairs and high/low twins from discordant pairs was found for the prefrontal lobes. The concordant high-risk pairs showed volume loss in orbitofrontal subdivisions. High-risk members from the discordant twin pairs exhibited volume reduction in the right inferior dorsolateral prefontal cortex. In addition, the posterior corpus callosum was compromised in concordant high-risk pairs, only. Our findings indicate that inattention and hyperactivity symptoms are associated with anatomical abnormalities of a distributed action-attentional network. Different brain areas of this network appear to be affected in inattention/hyperactivity caused by genetic (i.e., high concordant MZ pairs) vs. environmental (i.e., high-low discordant MZ pairs) risk factors. These results provide clues that further our understanding of brain alterations in ADHD. © 2007 Elsevier Inc. All rights reserved

Narrowband Searches for Continuous and Long-duration Transient Gravitational Waves from Known Pulsars in the LIGO-Virgo Third Observing Run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours-months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets. © 2022. The Author(s). Published by the American Astronomical Society

Escaping the immune system: How the malaria parasite makes vaccine development a challenge

Malaria is a major cause of morbidity and mortality. Immunity is acquired but is suboptimal, being slow to develop and incomplete. An inadequate understanding of natural immunity, host–parasite interactions, and a lack of reliable immune correlates of protection that could predict vaccine efficacy in the field have hindered development of a vaccine. With data from Phase III trials indicating that the leading malaria vaccine candidate, RTS,S, has limited efficacy, it is necessary to reconsider approaches to the development of a vaccine capable of inducing long-lived protection.Office of the Snr Dep Vice Chancellor, Institute for GlycomicsNo Full Tex

Q-cgi: new techniques to assess variation in perception applied to facial attractiveness

We present novel methods for assessing variation in the perception of subjective cues based on a fusion of Q-methodology with computer graphics techniques. Participants first Q-sort face stimuli based upon a subjective quality; a randomization-based statistic is then calculated to test whether groups of participants differ in their perception. Computer graphics are then used to extract and illustrate the differences in the manner which participants sorted so that the differences can be quantified. As a demonstration, the technique is applied to investigate the effects of prospective relationship duration and of sexual restrictiveness on the characteristics which participants find attractive in photographs of opposite-sex faces. Results show that in a naturally varying set of faces, female participants prefer facial cues related to masculinity for short-term relationships, whereas characteristics related to positive personality attributes are preferred for long-term relationships. For short-term relationships, male participants appear to prefer more feminine, youthful faces. Preferences of individuals with less restricted sexual strategy paralleled short-term preferences in that more feminine female faces and more masculine male faces were preferred