A proposed new policy for planetary protection

A critical review of the present policy was conducted with emphasis on its application to future planetary exploration. The probable impact of recent data on the implementation of the present policy was also assessed. The existing policy and its implementation were found to: be excessive for certain missions (e.g., Voyager), neglect the contamination hazard posed by the bulk constituent organics of spacecraft, be ambiguous for certain missions (e.g., Pioneer Venus), and treat all extraterrestrial sample return missions alike. The major features of the proposed policy are planet/mission combinations, a qualitative top level statement, and implementation by exception rather than rule. The concept of planet/mission categories permits the imposition of requirements according to both biological interest in the target planet and the relative contamination hazard of the mission type

Viking on Mars: The carbon assimilation experiments

A fixation of atmospheric carbon, presumably into organic form, occurs in Martian surface material under conditions approximating the actual Martian ones. The reaction showed the following characteristics: The amount of carbon fixed is small by terrestrial standards; highest yields were observed in the light, but some dark activity was also detected; and heating the surface material to 90°C for nearly 2 hours had no effect on the reaction, but heating to 175°C for 3 hours reduced it by nearly 90%. New data from Mars do not support an earlier suggestion that the reaction is inhibited by traces of water. There is evidence of considerable heterogeneity among different samples, but different aliquots from the same sample are remarkably uniform in their carbon-fixing capacity. In view of its thermostability it is unlikely that the reaction is biological

Congruence modularity implies cyclic terms for finite algebras

An n-ary operation f : A(n) -> A is called cyclic if it is idempotent and f(a(1), a(2), a(3), ... , a(n)) = f(a(2), a(3), ... , a(n), a(1)) for every a(1), ... , a(n) is an element of A. We prove that every finite algebra A in a congruence modular variety has a p-ary cyclic term operation for any prime p greater than vertical bar A vertical bar

Mind-mindedness and preschool children’s behavioral difficulties: the moderating role of maternal parenting distress

Mind-mindedness (MM) is a caregiver’s tendency to appreciate their infant’s internal mental states. This longitudinal study investigated whether maternal MM (10 months) was linked with children’s later behavioral problems (51 months) and the moderating role of maternal parenting distress (PD; 36 months) in a sample of 91 mother–infant dyads. Appropriate MM comments were coded from video-recorded, semi-structured play interactions between mothers and their infants; PD was obtained from maternal completion of the PD subscale of the Parenting Stress Index – Short Form (PSI-SF); and child internalizing and externalizing behavior problems were gathered from maternal report on the Strengths and Difficulties Questionnaire (SDQ). Moderated regression analyses revealed higher early appropriate MM was associated with significantly fewer internalizing emotional problems at 51 months among mothers with lower PD at 36 months, and higher early appropriate MM was associated with lower conduct problems at 51 months in mothers with higher PD at 36 months. Findings demonstrated the importance of considering nuanced contexts such as at-risk mothers and differential presentations of child difficulties in the analysis of the relationship between MM and child behavioral difficulties and the development of MM interventions

Venus - Preliminary science objectives and experiments for use in advanced mission studies

Mission planning and experiment design for future Mariner-type Venus space probe