This paper reviews the distribution of methane (CH 4 ) in our Solar System, as well as its sources and sinks in the atmospheres of the main Solar System bodies. Methane is widely distributed in the Solar System. In general, the inner planets are methane-poor, being Earth a unique exception, whereas the outer planets have CH 4 -rich atmospheres. In general, the atmospheric chemistry of this compound is dominated by the solar radiation although in O 2 -rich atmospheres this compound participates in a reaction system that removes atmospheric CH 4 . In our planet most of the atmospheric CH 4 is produced by lifeforms, reason why scientists have proposed that the simultaneous detection of methane signal along with oxygen (O 2 ) or ozone (O 3 ) signals in the atmospheric spectra of planets may be good evidence of life. Therefore, the study of this gas at planetary level is important for understanding the chemical reactions that control its abundance on the exoplanetary atmospheres and to classify possible inhabited planets.Keywords: methane, biosignatures, Solar System. Resumen El objetivo del este trabajo es hacer una revisión sobre la distribución del metano (CH 4 ) dentro del Sistema

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Neurological Soft Signs and cognitive processes in Mexican schoolchildren aged 6 to 11 yearsAbstrac Neurological Soft Signs (NSS) are indicative of generalized disruptions in neurological networks of cortico-subcortical areas.Their presence leads to problems in children's cognitive development with future academic repercussions. The presence of NSS was assessed and compared in 144 children aged 6 to 11 years of low-medium socioeconomic status from Mexico City and the metropolitan area through the Infant Neuropsychological Maturity Questionnaire (CUMANIN, for its Spanish acronym) and the School Neuropsychological Maturity Questionnaire (CUMANES, for its Spanish acronym). Results indicate significant differences by sex. Girls showed better performance in word articulation. In groups by age, significant differences were found in leximetriccomprehension, visual perception and executive function-errors. Participants showed the presence of developmental NSS which include: language (articulation disorders, oral and written language disturbances, difficulty finding words), psychomotricity, visual perception and other cognitive functions. There are several factors related to those impairments such as age, socioeconomic context and critical stages in child´s development. Identification and early diagnosis can reduce the risk of school failure.

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