This investigation examined the efficacy of psychostimulant therapy in alleviating neurobehavioral dysfunction attendant to pediatric brain injury. The most commonly reported neurobehavioral sequelae associated with head injury in the pediatric population involve deficits along the attentional matrix. This is also the most common objectively documented neurobehavioral finding among children as well as adults. There are several investigations in the adult literature which have employed the use of psychostimulants in treating both psychiatric and neuropsychological residua associated with head injury. Overall, the results of these studies are equivocal, but suggest a beneficial impact on general functioning. The present prospective investigation utilized a double-blind, placebo-controlled, cross-over experimental design to examine the efficacy of methylphenidate in treating children with acquired attentional disorders secondary to brain injury. A cohort of 14 children with varying degrees of head injury were recruited for participation. As expected, differences between drug and placebo conditions uniformly achieved statistical significance. Additionally, there were no differences in performance between baseline and placebo conditions on neurobehavioral tasks of attention and concentration. Current findings suggest that methylphenidate (and probably other psychostimulants such as Cylert, Adderal, Wellbutrin and dextroamphetamine sulfate) is an extremely effective agent in treating attentional disorders secondary to brain injury in children.

Abstract. Measurements of biogenic volatile organic compounds (VOCs) were performed at Hyytiälä, a Boreal forest site in Southern Finland as part of the project OSOA (origin and formation of secondary organic aerosol) in August 2001. At this site, frequent formation of new particles has been observed and the role of biogenic VOCs in this process is still unclear. Tethered balloons served as platforms to collect VOC samples within the planetary boundary layer at heights up to 1.2 km above ground during daytime. Mean mixed layer concentrations of total monoterpenes varied between 10 and 170 pptv, with α-pinene, limonene and Δ3-carene as major compounds, isoprene was detected at levels of 2–35 pptv. A mixed layer gradient technique and a budget approach are applied to derive surface fluxes representative for areas of tens to hundreds of square kilometres. Effects of spatial heterogeneity in surface emissions are examined with a footprint analysis. Depending on the source area considered, mean afternoon emissions of the sum of terpenes range between 180 and 300 μg m−2 h−1 for the period of 2 to 12 August 2001. Surface fluxes close to Hyytiälä were higher than the regional average, and agree well with mean emissions predicted by a biogenic VOC emission model. Total rates of monoterpene oxidation were calculated with a photochemical model. The rates did not correlate with the occurrence of new particle formation, but the ozone pathway was of more importance on days with particle formation. Condensable vapour production from the oxidation of monoterpenes throughout the mixed layer can only account for a fraction of the increase in aerosol mass observed at the surface.

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The cichlid fishes of Lake Malawi are an excellent model group with which to study adaptive radiation and speciation; due to the vast number of individual species, large variation in feeding adaptations and behaviours, and relatively recent divergence are found. Males of many cichlid species will obtain and defend lek‐like territories, where they court potential mates in addition to foraging for food. Aspects of territory quality warrant investigation because of the relationship between reproductive success and territory defence success. In this study, we tested whether the presence of a small or large food resource had any effect on the preference of a gravid female for a potential mate. The results of this experiment suggest that the presence of a large food resource increases the attractiveness of a male to a potential mate. This may suggest that the presence of food alone may not be the most important factor, or there may be a threshold amount over which females are attracted. These results indicate that certain aspects of territory quality such as habitat type or proximity to a food resource may play a role in both intersexual and intrasexual selection mechanisms: perhaps even driving and possibly accelerating the speciation of certain lineages of cichlid fishes.