Human-Robot Teaming in a Multi-Agent Space Assembly Task

NASA's Human Space Flight program depends heavily on spacewalks performed by pairs of suited human astronauts. These Extra-Vehicular Activities (EVAs) are severely restricted in both duration and scope by consumables and available manpower. An expanded multi-agent EVA team combining the information-gathering and problem-solving skills of humans with the survivability and physical capabilities of robots is proposed and illustrated by example. Such teams are useful for large-scale, complex missions requiring dispersed manipulation, locomotion and sensing capabilities. To study collaboration modalities within a multi-agent EVA team, a 1-g test is conducted with humans and robots working together in various supporting roles

The Cultural Evolution of Democracy: Saltational Changes in A Political Regime Landscape

Transitions to democracy are most often considered the outcome of historical modernization processes. Socio-economic changes, such as increases in per capita GNP, education levels, urbanization and communication, have traditionally been found to be correlates or ‘requisites’ of democratic reform. However, transition times and the number of reform steps have not been studied comprehensively. Here we show that historically, transitions to democracy have mainly occurred through rapid leaps rather than slow and incremental transition steps, with a median time from autocracy to democracy of 2.4 years, and overnight in the reverse direction. Our results show that autocracy and democracy have acted as peaks in an evolutionary landscape of possible modes of institutional arrangements. Only scarcely have there been slow incremental transitions. We discuss our results in relation to the application of phylogenetic comparative methods in cultural evolution and point out that the evolving unit in this system is the institutional arrangement, not the individual country which is instead better regarded as the ‘host’ for the political system

Spiroindolines Identify the Vesicular Acetylcholine Transporter as a Novel Target for Insecticide Action

The efficacy of all major insecticide classes continues to be eroded by the development of resistance mediated, in part, by selection of alleles encoding insecticide insensitive target proteins. The discovery of new insecticide classes acting at novel protein binding sites is therefore important for the continued protection of the food supply from insect predators, and of human and animal health from insect borne disease. Here we describe a novel class of insecticides (Spiroindolines) encompassing molecules that combine excellent activity against major agricultural pest species with low mammalian toxicity. We confidently assign the vesicular acetylcholine transporter as the molecular target of Spiroindolines through the combination of molecular genetics in model organisms with a pharmacological approach in insect tissues. The vesicular acetylcholine transporter can now be added to the list of validated insecticide targets in the acetylcholine signalling pathway and we anticipate that this will lead to the discovery of novel molecules useful in sustaining agriculture. In addition to their potential as insecticides and nematocides, Spiroindolines represent the only other class of chemical ligands for the vesicular acetylcholine transporter since those based on the discovery of vesamicol over 40 years ago, and as such, have potential to provide more selective tools for PET imaging in the diagnosis of neurodegenerative disease. They also provide novel biochemical tools for studies of the function of this protein family

Competition and substitution between public transport modes

The management and understanding of modal split between public transport (PT) modes is of interest for numerous reasons. It may, for example, be desirable to stimulate passengers to switch from crowded buses and over to higher capacity rail. This requires a good understanding of drivers of transit modal substitution. The evidence put forward in this paper is based on more than 150 empirically estimated cross elasticities between PT modes from over 20 sources collected from Australia, Europe and USA. These sources include scientifically published evidence as well as grey literature. This evidence is coded into a database from which our paper presents and analyses the available cross-PT-modal demand relations. We focus on evidence for how fares, travel time and service intervals on PT ‘mode A’ affect the demand for PT ‘mode B’. Despite generally low levels of substitution between PT modes, passengers are particularly sensitive to in-vehicle, access/egress and waiting time in choosing PT mode and less so for fare variations. In general, rail demand is less sensitive to changes in bus than bus demand is to changes in rail. We also find that peak-hour demand more markedly switches between PT modes than off-peak demand does

Organic reactions in self-organized surfactant systems

The aim of this work has been to investigate how microemulsions and micellar systems can be used as reaction media to overcome reactant incompatibility, enhance reaction rates and especially to control product composition, i.e., introducing regioselectivity, in organic synthesis. It was found that a significant increase in reaction rate can be obtained in properly formulated self-assembled systems as compared to the rates obtained in non-surfactant systems. The reaction rate differed between different surfactant classes and in many of the reactions studied cationic surfactant systems performed better than nonionic surfactant systems. It was found that there can be a considerable difference in reaction rate also between self-assembled systems based on surfactants of the same class. Investigation of the rates of a substitution reaction in microemulsions based on either a fatty alcohol ethoxylate or a sugar-based amphiphile, both of which are nonionic surfactants, showed that the reaction went much faster in the system based on the ethoxylated surfactant. This was attributed to a lower dielectric constant of the surfactant headgroup layer of the fatty alcohol ethoxylate than of the sugar-based surfactant, which should result in higher reactivity of the attacking anionic nucleophile. An alternative explanation to the higher reactivity of the system based on the ethoxylated surfactant is that this microemulsion has a higher dynamics, i.e., faster rate of disintegration and reformation of the oil-water interface. A substitution reaction between an alkyl phenol and a water soluble electrophile was studied in microemulsions and in micellar systems based on either a nonionic or a cationic surfactant. It was found that the reaction went faster in the self-assembled systems based on cationic surfactant than in those based on nonionic surfactant and that the micellar systems gave higher reaction rates than the microemulsions. The high reactivity in the systems based on the cationic surfactant was attributed to formation of a π-cation complex between the benzene ring of the alkyl phenol and the surfactant headgroup. It was showed that the oil-water interface of microemulsions could be used as template to induce regioselectivity both of electrophilic aromatic substitutions and of nucleophilic aliphatic substitution reactions. Monosubstitution of a symmetrical bifunctional reactant constituted a particularly striking example of how a microemulsion can be used as a tool to control regioselectivity

Organic reactions in self-organized surfactant systems

The aim of this work has been to investigate how microemulsions and micellar systems can be used as reaction media to overcome reactant incompatibility, enhance reaction rates and especially to control product composition, i.e., introducing regioselectivity, in organic synthesis. It was found that a significant increase in reaction rate can be obtained in properly formulated self-assembled systems as compared to the rates obtained in non-surfactant systems. The reaction rate differed between different surfactant classes and in many of the reactions studied cationic surfactant systems performed better than nonionic surfactant systems. It was found that there can be a considerable difference in reaction rate also between self-assembled systems based on surfactants of the same class. Investigation of the rates of a substitution reaction in microemulsions based on either a fatty alcohol ethoxylate or a sugar-based amphiphile, both of which are nonionic surfactants, showed that the reaction went much faster in the system based on the ethoxylated surfactant. This was attributed to a lower dielectric constant of the surfactant headgroup layer of the fatty alcohol ethoxylate than of the sugar-based surfactant, which should result in higher reactivity of the attacking anionic nucleophile. An alternative explanation to the higher reactivity of the system based on the ethoxylated surfactant is that this microemulsion has a higher dynamics, i.e., faster rate of disintegration and reformation of the oil-water interface. A substitution reaction between an alkyl phenol and a water soluble electrophile was studied in microemulsions and in micellar systems based on either a nonionic or a cationic surfactant. It was found that the reaction went faster in the self-assembled systems based on cationic surfactant than in those based on nonionic surfactant and that the micellar systems gave higher reaction rates than the microemulsions. The high reactivity in the systems based on the cationic surfactant was attributed to formation of a π-cation complex between the benzene ring of the alkyl phenol and the surfactant headgroup. It was showed that the oil-water interface of microemulsions could be used as template to induce regioselectivity both of electrophilic aromatic substitutions and of nucleophilic aliphatic substitution reactions. Monosubstitution of a symmetrical bifunctional reactant constituted a particularly striking example of how a microemulsion can be used as a tool to control regioselectivity