Evolutionary Consequences of Altered Atmospheric Oxygen in Drosophila melanogaster

Twelve replicate populations of Drosophila melanogaster, all derived from a common ancestor, were independently evolved for 34+ generations in one of three treatment environments of varying PO2: hypoxia (5.0–10.1 kPa), normoxia (21.3 kPa), and hyperoxia (40.5 kPa). Several traits related to whole animal performance and metabolism were assayed at various stages via “common garden” and reciprocal transplant assays to directly compare evolved and acclimatory differences among treatments. Results clearly demonstrate the evolution of a greater tolerance to acute hypoxia in the hypoxia-evolved populations, consistent with adaptation to this environment. Greater hypoxia tolerance was associated with an increase in citrate synthase activity in fly homogenate when compared to normoxic (control) populations, suggesting an increase in mitochondrial volume density in these populations. In contrast, no direct evidence of increased performance of the hyperoxia-evolved populations was detected, although a significant decrease in the tolerance of these populations to acute hypoxia suggests a cost to adaptation to hyperoxia. Hyperoxia-evolved populations had lower productivity overall (i.e., across treatment environments) and there was no evidence that hypoxia or hyperoxia-evolved populations had greatest productivity or longevity in their respective treatment environments, suggesting that these assays failed to capture the components of fitness relevant to adaptation

Aneurisma paraclinóideo: técnica cirúrgica e resultados em 51 pacientes Paraclinoid aneurysms: surgical technique and results in 51 patients

Analisam-se 51 pacientes portadores de 55 aneurismas paraclinóideos (APC) submetidos a tratamento cirúrgico. Em decorrência de tratar-se de procedimento de alta complexidade, descrevemos em pormenor os seus aspectos técnicos. O processo clinóideo anterior foi removido por via extradural após secção da duplicação dural da tenda da fissura orbitária superior e/ou por via intradural. Conseguiu-se exclusão do APC nos 51 pacientes. Em dois casos a clipagem foi parcial e, em três, ocorreu oclusão da ACI. Em 42 (82%) pacientes ocorreu bom resultado; em 5 (10%), incapacidade moderada; em 1 (2%), incapacidade grave e três (6%) faleceram por infarto cerebral. Sete (13,7%) pacientes tiveram lesão adicional do nervo óptico, sendo parcial em 4 (7,7%) e total em 3 (6%).<br>An analysis of the surgical results of 51 patients harboring 55 paraclinoid aneurysms is performed, along with a throughoutful description of it’s complex microsurgical technique. The anterior clinoid process was removed by the extradural route after sectioning the dural duplication between the superior orbital fissure and the dura of the temporal lobe, and/or by the intradural approach. All 55 aneurysms was excluded. In two cases the clipping was partial and the internal carotid artery were ocluded in three cases. The surgical outcome was good in 42 (82%) patients, moderate incapacity occurred in five (10%) and severe incapacity in one patient (2%). Three patients (6%) died due to brain infarction. Seven patients (13,7%) had adicional lesion of the optic nerve, being partial in 4 (7,7%) and total in 3 (6%)

Thermodynamic Formalism Of Neural Computing

Neural networks are systems of interconnected processors mimicking some of the brain functions. After a rapid overview of neural computing, the thermodynamic formalism of the learning procedure is introduced. Besides its use in introducing efficient stochastic learning algorithms, it gives an insight in terms of information theory. Main emphasis is given in the information restitution process; stochastic evolution is used as the starting point for introducing statistical mechanics of associative memory. Instead of formulating problems in their most general setting, it is preferred stating precise results on specific models. In this report are mainly presented those features that are relevant when the neural net becomes very large. A survey of the most recent results is given and the main open problems are pointed out