A survey of multiple missions using gravity-assisted trajectories

Launch opportunities and advantages of gravity- assisted multiple missions to specific solar system target

Asteroid mission alternatives

The options for asteroid missions are evaluated within the constraints of existing or planned launch vehicles and low-thrust propulsion systems. A wide variety of missions is possible, including flyby, rendezvous, and even sample return. The multi-asteroid rendezvous concept requires an ion drive low-thrust propulsion system of the type being developed for a comet rendezvous. It is indicated that there are plentiful opportunities for such missions to visit four asteroids with stay times of 60-90 days each and with transit times between rendezvous of the order of a year

Trajectory and propulsion characteristics of comet rendezvous opportunities

Trajectory and propulsion characteristics of spacecraft rendezvous mission opportunities to comets during 1975 to 199

Pioneer Mars 1979 mission options

A preliminary investigation of lower cost Mars missions which perform useful exploration objectives after the Viking/75 mission was conducted. As a study guideline, it was assumed that significant cost savings would be realized by utilizing Pioneer hardware currently being developed for a pair of 1978 Venus missions. This in turn led to the additional constraint of a 1979 launch with the Atlas/Centaur launch vehicle which has been designated for the Pioneer Venus missions. Two concepts, using an orbiter bus platform, were identified which have both good science potential and mission simplicity indicative of lower cost. These are: (1) an aeronomy/geology orbiter, and (2) a remote sensing orbiter with a number of deployable surface penetrometers

The accessible regions presentation of gravity-assisted trajectories using Jupiter

Accessibility of solar system regions to earth launched spacecraft using Jupiter gravity- assisted trajectorie

Orbital imagery for planetary exploration. Volume 3 - Orbit selection and definition

Orbital imagery for planetary exploration - orbital selections for Mars, Venus, Mercury, and Jupite

Appropriating Risk Factors: The Reception of an American Approach to Chronic Disease in the two German States, c. 1950–1990

Risk factors have become a dominant approach to the aetiology of chronic disease worldwide. The concept emerged in the new field of chronic disease epidemiology in the United States in the 1950s, around near-iconic projects such as the Framingham Heart Study. In this article I examine how chronic disease epidemiology and the risk factor concept were adopted and adapted in the two German states. I draw on case studies that illuminate the characteristics of the different contexts and different take on traditions in social hygiene, social medicine and epidemiology. I also look at critics of the risk factor approach in East and West Germany, who viewed risk factors as intellectually dishonest and a new surveillance tool

Biogeography of key mesozooplankton species in the North Atlantic and egg production of Calanus finmarchicus

Here we present a new, pan-North-Atlantic compilation of data on key mesozooplankton species, including the most important copepod, Calanus finmarchicus. Distributional data of eight representative zooplankton taxa, from recent (2000–2009) Continuous Plankton Recorder data, are presented, along with basin-scale data of the phytoplankton colour index. Then we present a compilation of data on C. finmarchicus, including observations of abundance, demography, egg production and female size, with accompanying data on temperature and chlorophyll. This is a contribution by Canadian, European and US scientists and their institutions: http://doi.pangaea.de/10.1594/PANGAEA.820732, http://doi.pangaea.de/10.1594/PANGAEA.824423, http://doi.pangaea.de/10.1594/PANGAEA.828393 (please also see Melle et al., 2013; Castellani and Licandro, 2013; Jónasdóttir et al., 2014)

Differential behavioral and physiological effects of anodal transcranial direct current stimulation in healthy adults of younger and older age

Changes in γ-aminobutyric acid (GABA) mediated synaptic transmission have been associated with age-related motor and cognitive functional decline. Since anodal transcranial direct current stimulation (atDCS) has been suggested to target cortical GABAergic inhibitory interneurons, its potential for the treatment of deficient inhibitory activity and functional decline is being increasingly discussed. Therefore, after-effects of a single session of atDCS on resting-state and event-related short-interval intracortical inhibition (SICI) as evaluated with double-pulse TMS and dexterous manual performance were examined using a sham-controlled cross-over design in a sample of older and younger participants. The atDCS effect on resting-state inhibition differed in direction, magnitude, and timing, i.e., late relative release of inhibition in the younger and early relative increase in inhibition in the older. More pronounced release of event-related inhibition after atDCS was exclusively seen in the older. Event-related modulation of inhibition prior to stimulation predicted the magnitude of atDCS-induced effects on resting-state inhibition. Specifically, older participants with high modulatory capacity showed a disinhibitory effect comparable to the younger. Beneficial effects on behavior were mainly seen in the older and in tasks requiring higher dexterity, no clear association with physiological changes was found. Differential effects of atDCS on SICI, discussed to reflect GABAergic inhibition at the level of the primary motor cortex, might be distinct in older and younger participants depending on the functional integrity of the underlying neural network. Older participants with preserved modulatory capacity, i.e., a physiologically "young" motor network, were more likely to show a disinhibitory effect of atDCS. These results favor individually tailored application of tDCS with respect to specific target groups