Adverse environments are linked to elevated youth antisocial behavior. However, this relation is thought to depend, in part, on genetic susceptibility. The present study investigated whether polygenic risk for antisociality moderates relations between hostile environments and stable as well as dynamic antisocial behaviors across adolescence. We derived two antisocial-linked polygenic risk scores (PRS) (N = 721) based on previous genome-wide association studies. Forms of antisocial behavior (nonaggressive conduct problems, physical aggression, social aggression) and environmental hostility (harsh parenting and school violence) were assessed at age 13, 15, and 17 years. Relations to individual differences stable across adolescence (latent stability) vs. time-specific states (timepoint residual variance) of antisocial behavior were assessed via structural equation models. Higher antisocial PRS, harsh parenting, and school violence were linked to stable elevations in antisocial behaviors across adolescence. We identified a consistent polygenic-environment interaction suggestive of differential susceptibility in late adolescence. At age 17, harsher parenting was linked to higher social aggression in those with higher antisocial PRS, and lower social aggression in those with lower antisocial PRS. This suggests that genetics and environmental hostility relate to stable youth antisocial behaviors, and that genetic susceptibility moderates home environment-antisocial associations specifically in late adolescence.

Protoplanetary discs are made of gas and dust orbiting a young star. They are also the birth place of planetary systems, which motivates a large amount of observational and theoretical research. In these lecture notes, I present a review of the magnetic mechanisms applied to the outer regions ($R\gtrsim 1\ \mathrm {AU}$) of these discs, which are the planet-formation regions. In contrast to usual astrophysical plasmas, the gas in these regions is noticeably cold ($T < 300\ \mathrm {K}$) and dense, which implies a very low ionisation fraction close to the disc midplane. In these notes, I deliberately ignore the innermost $(R\sim 0.1\ \mathrm {AU})$ region, which is influenced by the star–disc interaction and various radiative effects. I start by presenting a short overview of the observational evidence for the dynamics of these objects. I then introduce the methods and approximations used to model these plasmas, including non-ideal magnetohydrodynamics, and the uncertainties associated with this approach. In this framework, I explain how the global dynamics of these discs is modelled, and I present a stability analysis of this plasma in the local approximation, introducing the non-ideal magneto-rotational instability. Following this mostly analytical part, I discuss numerical models that have been used to describe the saturation mechanisms of this instability, and the formation of large-scale structures by various saturation mechanisms. Finally, I show that local numerical models are insufficient because magnetised winds are also emitted from the surface of these objects. After a short introduction on wind physics, I present global models of protoplanetary discs, including both a large-scale wind and the non-ideal dynamics of the disc.

Spinal deformities have been evaluated in a five year retrospective study where 28 boys and 25 girls all having Friedreich's ataxia were on the average assessed once a year in a multidisciplinary clinic. Scoliosis seems somewhat more progressive in girls than in boys and more severe in non-ambulatory than ambulatory patients. Some of those scolioses are very progressive reaching 60° to 100° Cobb angle values requiring spinal surgery while other progress less rapidly and do well on their own. In addition it was shown that the intrinsic geometric spine curve parameters namely that of curvature and torsion are a powerful diagnostic tool in the assessment of evolutive scoliosis.

We studied free plasma catecholamines in 23 patients with Friedreich’s ataxia, having a mean age of 22 ± 9.6 (SD) years. Conjugated catecholamines were also studied in 10 patients. Mean plasma norepinephrine and epinephrine were significantly higher than controls both in the supine and standing positions. In total 15 out of 23 patients (65%) had increased free and/or conjugated plasma catecholamines. The increase in plasma catecholamines was more marked in patients with severe neuromotor impairment. Among the patients with left ventricular concentric hypertrophy (wall thickness >12 mm), only 3 had no demonstrable sympathetic hyperfunction.

Since the high local concentrations of norepinephrine at the site of release from sympathetic nerve terminals may serve as a trigger for the hypertrophic response of the myocardial cell, it is suggested that early pharmacological intervention could prevent or limit the cardiomyopathic process or its clinical consequences.

Echocardiographic examination of 21 patients with Friedreich's ataxia (age 7 to 28 years) showed cardiac abnormalities in 90% of the cases. They were characterized by varying degrees of septal hypertrophy in 81%, left ventricular free wall hypertrophy in 61%, and a slight reduction of left ventricular internal dimension in 57% of the cases. Asymmetric septal hypertrophy (ASH) with a septal/left ventricular free wall ratio of over 1.3 was found in 29% of the cases, and systolic anterior motion (SAM) of the mitral valve in three patients. Two other patients showed evidence of a different type of cardiomyopathy with marked symmetric left ventricular hypertrophy and marked left ventricular enlargement.

A three-dimensional geometric model of the foot's bony structure based on the use of a stereoradiographic technique is presented. To illustrate the potential of such a model it has been applied here to the study of cavus foot in a patient having Friedreich's ataxia. This model permits an accurate evaluation of this complex spatial foot deformity.

Lecithin and sqfflower oil brought about the same changes in serum LAD activity and kinetics in patients with Friedreich’s Ataxia as in controls when results of this double-blind crossover study were analyzed according to group assignation. According to functional stages, pretrial LAD activity decreased with advancing severity while Km for lipoamide increased. Lecithin and sqfflower oil supplements corrected the elevated Km for lipoamide but produced a further reduction in LAD activity. These changes may have been due to the increased intake of linoleic acid, a precursor of lipoic acid, which is present in high percentage in both lecithin and safflower oil. Results of the biochemical study thus agreed with the clinical data gathered during the course of the one-year trial in suggesting that linoleic acid may well have been the active factor through which biochemical and clinical improvement was previously observed in patients with Friedreich’s Ataxia supplemented with lecithin.

The preliminary results based on a three year study on the evolution and management of scoliosis in Friedreich’s ataxia are presented. Thirty-two patients were followed in the Neuromuscular Disease Clinic at Sainte-Justine Hospital where standardized spinal radiographs were taken periodically with the Scoliosis Chariot and the Throne.

Pathomechanics — Between the age groups I (5 – 10 years) and II (10 – 15 years), a substantial increase in the Cobb values occurs. Associated with it, an increase was observed in the thoracic and thoraco-lumbar projected surface area indices. The relative torsion between the thoracic and lumbar segments was associated with a sudden increase in the Cobb measurements.

A computer program which generates a tri-dimensional display of the spine from the coordinates obtained from the standardized radiographs has been adapted to study the importance and influence of the thoracic torsion on the progress of the scoliosis and on the evolution of the total spinal deformity.

Management — Prevention of the progression of established curves was our main objective. Careful examination of the spine, depending on the age of the child, in our preliminary study, stimulated early orthopaedic treatment in any curve of 20° or more. There was always concern for curves of 30° or more. In the growing child, bracing which was recommended is now under a more thorough investigation. The use of spinal pacemakers is being clinically evaluated.

In the older child, the curve was usually stable after sixteen years of age. Surgery was usually attempted in curves over 40° in the growing child. The same curve was usually stable after the growth period.

For the non-ambulatory patients, the present study suggested the prescription of a molded seat with the following characteristics: i) a posterior lumbar support, ii) low thoracic lateral supports and Hi) a slight inclination of the seating system. This was presumed to be beneficial in maintaining stability of the spine.

Many HIV-infected children have neurological involvement. We present our observations in 49 cases, 58% of which had some form of clinical neurological impairment. Most of the patients affected (71%) presented with progressive encephalopathy, characterized by developmental delay with loss of acquisitions and cognitive decline, an impaired growth curve, microcephaly and corticospinal dysfunction. CT-scan imaging shows cerebral atrophy in all cases and basal ganglia calcifications in 29%. Non-specific abnormalities are found on the EEG in two-thirds of cases and in the CSF in slightly less than half the cases. Pathological studies sometime revealed HIV encephalitis or lateral corticospinal tracts degeneration. Neurological impairment secondary to vascular events, neoplasms or opportunistic infections were rare, especially when compared with the adult HIV population.

A simple radiographic apparatus standardizing foot position and simulating weight-bearing effects in the feet is described in this paper. It provides an effective means of obtaining reliable radiographic data for both ambulatory and nonambulatory patients. This device is presently used in an on-going study on pes cavus in Friedreich's ataxia.

Several authors have recently reported a neurological disorder associated with chronic vitamin E deficiency in man. Except in one patient, this deficiency has always been secondary to an underlying disease resulting in lipid malabsorption. We report a second case of such a neurological syndrome in a patient in whom vitamin E deficiency was an isolated finding.

The clinical picture in our patient was characterized by a diffuse muscle weakness most prominent distally and in the lower limbs, generalized areflexia, a decrease in proprioception and vibration sense and slight limb and gait ataxia. His condition improved on alpha tocopherol therapy so that it is very likely that vitamin E deficiency is responsible for his neurological deficit.

Since in our patient as well as in several other reported cases this condition has been treatable, it is important that this syndrome be recognized in children presenting a suggestive clinical picture even if they do not have lipid malabsorption.

Doping of silicon with chalcogens (S, Se, Te) by femtosecond laser irradiation to concentrations well above the solubility limit leads to near-unity optical absorptance in the visible and infrared (IR) range and is a promising route toward silicon-based IR optoelectronics. However, open questions remain about the nature of the IR absorptance and in particular about the impact of the dopant distribution and possible role of dopant diffusion. Here we use electron tomography using a high-angle annular dark-field (HAADF) detector in a scanning transmission electron microscope (STEM) to extract information about the three-dimensional distribution of selenium dopants in silicon and correlate these findings with the optical properties of selenium-doped silicon. We quantify the tomography results to extract information about the size distribution and density of selenium precipitates. Our results show correlation between nanoscale distribution of dopants and the observed sub-band gap optical absorptance and demonstrate the feasibility of HAADF-STEM tomography for the investigation of dopant distribution in highly-doped semiconductors.

The multiplication of magnetic domain walls under the effect of induced currents developed during high frequency magnetization loops is experimentally investigated in ultra-soft nanocristalline alloys in order to determine the effective anisotropy and to check the predictions of the Random Anisotropy Model used to explain their extreme softness. For the first time, direct observation of multiplication is achieved and resulting effective anisotropy determinations underline the importance of induced anisotropy upon effective anisotropy.

The hypothesis that the periods of dormancy previously described in the millipede Polydesmus angustus may be photoperiodically induced diapauses was tested experimentally. In this species, biennial individuals exhibit two successive periods of dormancy: aestivation in the penultimate stadium (stadium VII) and reproductive dormancy in the adults, which emerge in autumn. It was first established that the reproductive dormancy is not a thermally controlled state of quiescence. When adults emerging in autumn were kept at 16 °C under natural photoperiod, their reproduction was delayed for several months in comparison with adults emerging in spring at similar temperatures. This indicates that the reproductive dormancy begins with a period of diapause. Further experiments provided evidence of a photoperiodic induction of the adult diapause. When millipedes were reared under short day length (L:D 12:12 h) throughout their development, they required more time to reproduce than millipedes reared under long day length (L:D 16:8 h) at the same temperatures. Photoperiod influenced reproduction in females, but no significant effects were detected in adult males. On the other hand, stadium VII was markedly longer at L:D 16:8 h than at L:D 12:12 h in both sexes, which strongly suggests that aestivation is also induced by photoperiod. However, the effects on the duration of stadium VII varied among individuals, some of which showed no response to long days. This study is the first to document photoperiodic regulation of the life cycle in the class Diplopoda, a trait common in other classes of terrestrial arthropods.

Light and scanning electron microscopy investigations were carried out to identify and count the chemoreceptors on the legs of the tsetse, Gbssina tachinoides Westwood, and topographical maps, considered of value in electrophysiological and behavioural research are presented. The candidate chemoreceptors are located on the femorae, the tibiae and the tarsi and are more abundant on the ventral zone of each segment. The study demonstrates that the prothoracic, mesothoracic and metathoracic legs have a similar number of chemoreceptors and male flies possess more than female (1033 and 570, respectively). The variability of the number of chemoreceptors on the prothoracic legs has been estimated in both sexes.