Cellular Based Aggregated Satellite System: The Design and Architecture of a Three Degree of Freedom Near-Frictionless Testbed for Ground Validation of CubeSat Operations

As small and nano-satellite operations become more complex and increase in functionality, the need to validate new concepts prior to deployment in a low-cost and time efficient manner has further increased. While computer simulations have traditionally provided acceptable results for guidance navigation and control (GNC) algorithms, more complex actions such as rendezvous and proximity operations and docking (RPOD) require alternative methods, which often require ground-based platforms. The concept of on-orbit autonomous docking of small satellites has grown in popularity due to its broad range of applications. However, most existing ground testing platforms (GTP) are expensive due to the technologies used and large physical space required. Due to the importance of RPOD to nano-satellites specifically, the development of a low-profile GTP is a crucial component in the testing and validation of small satellite concepts. The Space Engineering Research Center (SERC) at the University of Southern California (USC) has designed and manufactured a GTP capable of validating various unique nano-satellite operations in a cost-effective and space-efficient manner. This paper will focus on the design and architecture of a three degree of freedom (3DoF) near-frictionless testbed for ground validation of RPOD in a microgravity environment and its use with various small satellite applications

Concise total synthesis of (+)-gliocladins B and C

The first total synthesis of (+)-gliocladin B is described. Our concise and enantioselective synthesis takes advantage of a new regioselective Friedel–Crafts-based strategy to provide an efficient multigram-scale access to the C3-(3′-indolyl)hexahydropyrroloindole substructure, a molecular foundation present in a significant subset of epipolythiodiketopiperazine natural alkaloids. Our first-generation solution to (+)-gliocladin B involved the stereoselective formation of (+)-12-deoxybionectin A, a plausible biosynthetic precursor. Our synthesis clarified the C15 stereochemistry of (+)-gliocladin B and allowed its full structure confirmation. Further studies of a versatile dihydroxylated diketopiperazine provided a concise and efficient synthesis of (+)-gliocladin B as well as access to (+)-gliocladin C.National Institute of General Medical Sciences (U.S.) (GM089732)Amgen Inc.National Science Foundation (U.S.) (CHE-0946721

Perceived environmental risk as a predictor of teenage motherhood in a British population

Previous studies have shown that strong relationships exist between deprived environments and teenage motherhood. However, such studies have predominantly identified deprivation using neighbourhood-wide measures of socio-economic status. Few studies of teenage parenthood have examined how individuals perceive their environment and the importance of this perception on reproductive behaviour and timing. Using data collected from a sample of women living the county of Gloucestershire, UK, this paper explores the predictive value of two methods of assessing the environment: (1) the structural component—deprivation at the neighbourhood level and (2) the individual’s subjective experience of her pre-pregnancy environment, when examining how the wider environmental context can influence the decision of becoming a teenage mother. The results indicate that a woman’s perception of her neighbourhood of residence at the time she conceived, her perceived environmental risk, may be a more discriminating predictor of teenage motherhood than deprivation measured by ward economic and deprivation indicators