During this age window, forebrain dopamine systems undergo profuse remodeling, thus providing a neuro-biological substrate to explain behavioral peculiarities observed during adolescence, as well as the reported vulnerabilities to several drugs. Further, methylphenidate (MPH, better known as Ritalin (R)), a psychostimulant extensively prescribed to children and adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD),
raises concerns for its long-term safety. Using magnetic resonance techniques, MPH-induced acute effects appear to be different in adolescent rats compared to adult animals. Moreover, adolescent exposure to MPH seems to provoke persistent neurobehavioral consequences: long-term modulation of self-control abilities, decreased sensitivity to natural and drug reward, enhanced stress-induced click here emotionality, together with an enhanced cortical control over subcortical dopamine systems and an enduring up-regulation of Htr7 gene expression within the nucleus
accumbens (NAcc). In summary, additional studies in animal models are necessary to better understand the long-term consequences of adolescent MPH, and to further investigate the safety of the prescription and administration of such pharmacological treatment at early life stages. (c) 2011 Elsevier Ltd. All rights reserved.”
“Recently we have introduced a simplified model of ecosystem assembly (Capitan et al., 2009) for which we are able to map out all assembly pathways generated by external invasions in OICR-9429 an exact manner. In this paper we provide a deeper analysis
of the model, obtaining analytical results and introducing some approximations which allow us to reconstruct the results of our previous work. In particular, we show that the population dynamics equations of a very general class of trophic-level structured food-web have an unique interior equilibrium point which is globally stable. We show analytically Oxymatrine that communities found as end states of the assembly process are pyramidal and we find that the equilibrium abundance of any species at any trophic level is approximately inversely proportional to the number of species in that level. We also find that the per capita growth rate of a top predator invading a resident community is key to understand the appearance of complex end states reported in our previous work. The sign of these rates allows us to separate regions in the space of parameters where the end state is either a single community or a complex set containing more than one community. We have also built up analytical approximations to the time evolution of species abundances that allow us to determine, with high accuracy, the sequence of extinctions that an invasion may cause. Finally we apply this analysis to obtain the communities in the end states.