Inhibitory deficits in children with attention-deficit/hyperactivity disorder: Intentional versus automatic mechanisms of attention

Application of theoretically based tasks to the study of the development of selective attention has led to intriguing new findings concerning the role of inhibitory mechanisms. This study examined inhibitory mechanisms using a countermanding task and an inhibition of return task to compare deficits in intentionally, versus reflexively, controlled inhibition of attention in children with attention deficit hyperactivity disorder. Fifty children with attention-deficit/hyperactivity disorder (ADHD) were classified into one of three subtypes: predominantly inattentive (ADHD/PI), combined (ADHD/C), and those children with ADHD/C who also met criteria for comorbid oppositional defiant disorder (ADHD/C + ODD). The groups were compared to a comparison group of children (n = 21). The countermanding task showed that the ADHD groups required more time to inhibit responses and this impairment did not differ among subtypes. With respect to reflexively controlled inhibition, compared with controls ADHD/C and ADHD/C + ODD groups showed impaired reflexive inhibition, whereas the ADHD/PI group was considerably less impaired. The findings highlight a dissociation between the two forms of inhibitory deficits among children with the inattentive subtype, and raise the possibility that the efficient operation of reflexive inhibitory mechanisms might be necessary for the development of effective intentional control of inhibition

The merest logomachy: the 1868 Norwich discussion of aphasia by Hughlings Jackson and Broca

This article reconsiders the events that took place at the 1868 meeting of the British Association for the Advancement of Science (BA) in Norwich. Paul Broca and John Hughlings Jackson were invited to speak on the new and controversial subject of aphasia. Over the ensuing decades, there have been repeated references made to a debate between Broca and Jackson. This meeting has been identified as a turning point in favour of Broca's position on the cerebral localization of language. A return to original sources from key witnesses reveals that the opinion of the British practitioners was generally against Broca's views. Close examination of contemporaneous materials suggests that no public debate between Jackson and Broca occurred. However, the public discussion after Broca's presentation records notable concerns over both theoretical issues of localization of function and the status of exceptional clinical cases. A significant stage in the development of current views on the organization of language in the brain is revealed in the accounts of the BA meeting in August 1868 and successive responses to these events in the British press over a period of years

Cross-linguistic study of vocal pathology: perceptual features of spasmodic dysphonia in French-speaking subjects

Clinical characterisation of Spasmodic Dysphonia of the adductor type (SD) in French speakers by Klap and colleagues (1993) appears to differ from that of SD in English. This perceptual analysis aims to describe the phonetic features of French SD. A video of 6 French speakers with SD supplied by Klap and colleagues was analysed for frequency of phonatory breaks, pitch breaks, harshness, creak, breathiness and falsetto voice, rate of production, and quantity of speech output. In contrast to English SD, the French speaking SD patients demonstrated no evidence pitch breaks, but phonatory breaks, harshness and breathiness were prominent features. This verifies the French authors’ (1993) clinical description. These findings suggest that phonetic properties of a specific language may affect the manifestation of pathology in neurogenic voice disorders

Sperimagnetism in Fe(78)Er(5)B(17) and Fe(64)Er(19)B(17) metallic glasses: II. Collinear components and ferrimagnetic compensation

Magnetization measurements on an Fe(64)Er(19)B(17) glass and polarized-beam neutron scattering measurements on Fe(78)Er(5)B(17) and Fe(64)Er(19)B(17) were described in part I. The finite spin-flip neutron scattering cross sections were calculated using a sperimagnetic structure based on random cone arrangements of the magnetic moments. The temperature variation of the cross sections of Fe(64)Er(19)B(17) suggested that a compensated sperimagnetic phase existed at T(comp). The analysis of the non-spin-flip neutron scattering cross sections is described here in part II. Two spin-dependent total structure factors S(+/-+/-). (Q) were defined from these cross sections and, despite the limited range of the data 0.5 angstrom(-1) , are zero on both sublattices in the compensated sperimagnetic structure at T(comp). The pre-peak in the spin-dependent total structure factors at 112 K showed that it originated in the atomic structure and it may involve Fe-Er-Fe 'collineations' at a radial distance of approximate to 6.0 angstrom. Finally, the RDF(+/-+/-) (r) of Fe(64)Er(19)B(17) at 180 K and of Fe(78)Er(5)B(17) at 2 K show that both glasses have the (mu(Fe) UP:mu(Er) DOWN) structure like the (Fe, Tb)(83)B(17) collinear ferrimagnets

GridCertLib: a Single Sign-on Solution for Grid Web Applications and Portals

This paper describes the design and implementation of GridCertLib, a Java library leveraging a Shibboleth-based authentication infrastructure and the SLCS online certificate signing service, to provide short-lived X.509 certificates and Grid proxies. The main use case envisioned for GridCertLib, is to provide seamless and secure access to Grid/X.509 certificates and proxies in web applications and portals: when a user logs in to the portal using Shibboleth authentication, GridCertLib can automatically obtain a Grid/X.509 certificate from the SLCS service and generate a VOMS proxy from it. We give an overview of the architecture of GridCertLib and briefly describe its programming model. Its application to some deployment scenarios is outlined, as well as a report on practical experience integrating GridCertLib into portals for Bioinformatics and Computational Chemistry applications, based on the popular P-GRADE and Django softwares.Comment: 18 pages, 1 figure; final manuscript accepted for publication by the "Journal of Grid Computing

Direct Measurement of Mammalian Axonemal Dynein's Motor Activity.

Flagella and cilia play critical roles in mammalian and other eukaryotic life by providing propulsion for swimming cells and moving fluids across tissue surfaces. Flagellar/ciliary bending is caused by the sliding of doublet microtubules (MTs) past each other due to a molecular motor called dynein attached to one doublet MT (dMT) “walking” along an adjacent dMT. Due to dMTs being fixed at the same end, this translocation produces a bend in the whole structure. While it is clear how the dynein molecules cause a bending of the dMTs, the mechanism underlying the generation of propagated waves of flagellar/ciliary motion has yet to be fully understood, especially with regard to the magnitude and regulation of the forces produced by dynein. Several outside studies have shown that some of dynein's mechanical properties such as velocity of MT gliding and force generation seem to be regulated by its multiple nucleotide binding sites. To better understand dynein’s role in coordinated flagellar motion, we developed two in situ assays: one in which polymerized MTs glide along dMTs extruded from disintegrated bovine sperm flagella and an optical tweezers assay which is identical in geometry and environment except the MT is held in an optical trap to measure displacements and forces rather than velocities. The exposed, active dynein in each assay remain attached to their respective dMTs, allowing translocation of single MTs to be observed in an environment with direct control of chemical conditions. In the gliding assay, translocation of MTs by dynein exhibits Michaelis-Menten type kinetics, with Vmax = 4.7 ± 0.2 μm/sec and Km = 124 ± 11 μM. The character of MT translocation is variable, including smooth gliding, stuttered motility, oscillations, buckling, complete dissociation from the dMT, and occasionally movements reversed from the physiologic direction. The gliding velocity is independent of the number of dynein motors present and shows no indication of increased activity due to ADP regulation. In the optical tweezers assay, average force was found to be independent of [ATP] and [ADP] and distances of dynein’s excursions indicates non-processivity. These combined results reveal dynein’s motor activity, individually and cooperatively, within mammalian flagella.Ph.D.Biomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/75936/1/dlorch_1.pd

Victorian medical awareness of childhood language disabilities

Book synopsis: Disability and the Victorians brings together in one collection a range of topics, perspectives and experiences from the Victorian era that present a unique overview of the development and impact of attitudes and interventions towards those with impairments during this time. The collection also considers how the legacies of these actions can be seen to have continued throughout the twentieth century right up to the present day. Subjects addressed include deafness, blindness, language delay, substance dependency, imperialism and the representation of disabled characters in popular fiction. These varied topics illustrate how common themes can be found in how Victorian philanthropists and administrators responded to those under their care. Often character, morality and the chance to be restored to productivity and usefulness overrode medical need and this both influenced and reflected wider societal views of impairment and inability

Radio-telemetric evidence of migration in the gregarious but not the solitary morph of the Mormon cricket (Anabrus simplex : Orthoptera: Tettigoniidae

Abstract The Mormon cricket, Anabrus simplex, is one of just a few species of katydids (or bushcrickets, Orthoptera: Tettigoniidae) that, like migratory locusts, appear to have solitary and migratory morphs. Using radio telemetry we studied movements of individuals of two morphs of this flightless species. Individuals within each migratory band had similar rates of movements along similar directional headings whereas solitary individuals moved little and showed little evidence of directionality in movement. Our results also add to other recent radio-telemetry studies showing that flightless insects of 1-2 g in mass can be tracked successfully using these methods

The Effects of Stimulant Medication on the Online Story Narrations of Children with ADHD

The current study investigated the inclusion of goal-based story events in the online story narrations of children with ADHD, as compared with their peers, and explored the effect of stimulant medication on the narrations in children with ADHD. Children completed a narration task on two separate occasions. Children with ADHD (n = 17) completed one narration on medication and the other one on placebo. Results indicated that narrations of comparison children (n= 25) were significantly more likely than narrations of children with ADHD to include the story’s positive outcome, completion of the story’s overall goal, and specific attempts linked to the goal. Children with ADHD included a larger total number of clauses in their narrations when on stimulant medication than when on placebo, but medication showed no significant effects for any other variables. Results indicate that stimulant medication may not be effective at reducing goal-based story comprehension deficits in children with ADHD

The Effects of Stimulant Medication on Free Recall of Story Events among Children with ADHD

This study investigated group differences in the recalls of stories by children with attention-deficit/hyperactivity disorder (ADHD) and comparison peers. Further, the study examined whether stimulant medication improved the story recall of children with ADHD relative to a placebo condition. Children were asked to recall both televised and audio taped stories. Free recall protocols were assessed for what information was recalled as a function of story structure features (i.e. status on or off the causal chain and event importance) and were rated for overall coherence. Relative to comparison peers, children with ADHD showed less influence of story structure features on recall, and produced less coherent recall of the audio taped stories. Medication had only limited effects on the story recall of children with ADHD. Specifically, medication did not increase these children’s sensitivity to events central to the stories and had no effect on the coherence of children’s recalls. The implications of the results for guiding future academic interventions are discussed