Mariner IV Mission to Mars. Part I

This technical report is a series of individual papers documenting the Mariner-Mars project from its beginning in 1962 following the successful Mariner-Venus mission. Part I is pre-encounter data. It includes papers on the design, development, and testing of Mariner IV, as well as papers detailing methods of maintaining communication with and obtaining data from the spacecraft during flight, and expected results during encounter with Mars. Part 11, post-encounter data, to be published later, will consist of documentation of the events taking place during Mariner IV's encounter with Mars and thereafter. The Mariner-Mars mission, the culmination of an era of spacecraft development, has contributed much new technology to be used in future projects

‘Nature doesn’t care that we’re there’: Re-Symbolizing Nature’s ‘Natural’ Contingency

This article draws upon the work of Timothy Morton and Slavoj Žižek in order to critically examine how mountain bike trail builders orientated themselves within nature relations. Beginning with a discussion of the key ontological differences between Morton’s object-oriented ontology and Žižek’s blend of Hegelian- Lacanianism, we explore how Morton’s dark ecology and Žižek’s account of the radical contingency of nature, can offer parallel paths to achieving an ecological awareness that neither idealises nor mythologises nature, but instead, acknowledges its strange (Morton) and contingent (Žižek) form. Empirically, we support this theoretical approach in interviews with twenty mountain bike trail builders. These interviews depicted an approach to trail building that was ambivalently formed in/with the contingency of nature. In doing so, the trail builders acted with a sense of temporal awareness that accepted the radical openness of nature, presenting a ‘symbolic framework’ that was amiable to nature’s ambivalent, strange and contingent form. In conclusion, we argue that we should not lose sight of the ambivalences and strange surprises that emanate from our collective and unpredictable attempts to symbolize nature and that such knowledge can coincide with Morton’s ‘dark ecology’ – an ecological awareness that remains radically open to our ecological existence

Existence of KPP Type Fronts in Space-Time Periodic Shear Flows and a Study of Minimal Speeds Based on Variational Principle

We prove the existence of reaction-diffusion traveling fronts in mean zero space-time periodic shear flows for nonnegative reactions including the classical KPP (Kolmogorov-Petrovsky-Piskunov) nonlinearity. For the KPP nonlinearity, the minimal front speed is characterized by a variational principle involving the principal eigenvalue of a space-time periodic parabolic operator. Analysis of the variational principle shows that adding a mean-zero space time periodic shear flow to an existing mean zero space-periodic shear flow leads to speed enhancement. Computation of KPP minimal speeds is performed based on the variational principle and a spectrally accurate discretization of the principal eigenvalue problem. It shows that the enhancement is monotone decreasing in temporal shear frequency, and that the total enhancement from pure reaction-diffusion obeys quadratic and linear laws at small and large shear amplitudes

Evidence of road salt in New Hampshire’s snowpack hundreds of meters from roadways

Salinization of surface and groundwater has been directly linked to the area of road surfaces in a watershed and the subsequent wintertime maintenance used to keep roads free of snow and ice. Most studies that explore road salt in snow along roadways limit the study to within 100 m from a roadway and conclude that there is negligible deposition of de-icing salt at distances greater than 100 m. In this study, we analyze the ion content of the southern New Hampshire snowpack and use Mg2+ as a conservative sea-salt tracer to calculate sea salt and non-sea salt fractions of Cl−. There is a minimum of 60% non-sea salt Cl−, which we attribute to road salt, in the snowpack at our study sites 115 to 350 m from the nearest maintained roadways. This suggests that larger areas need to be considered when investigating the negative impact of Cl− loading due to winter-time maintenance

Heckle and Chide: Results of a Randomized Road Safety Intervention in Kenya

In economies with weak enforcement of traffic regulations, drivers who adopt excessively risky behavior impose externalities on other vehicles, and on their own passengers. In light of the difficulties of correcting inter-vehicle externalities associated with weak third-party enforcement, this paper evaluates an intervention that aims instead to correct the intra-vehicle externality between a driver and his passengers, who face a collective action problem when deciding whether to exert social pressure on the driver if their safety is compromised. We report the results of a field experiment aimed at solving this collective action problem, which empowers passengers to take action. Evocative messages encouraging passengers to speak up were placed inside a random sample of over 1,000 long-distance Kenyan minibuses, or matatus, serving both as a focal point for, and to reduce the cost of, passenger action. Independent insurance claims data were collected for the treatment group and a control group before and after the intervention. Our results indicate that insurance claims fell by a half to two-thirds, from an annual rate of about 10 percent without the intervention, and that claims involving injury or death fell by at least 50 percent. Results of a driver survey eight months into the intervention suggest passenger heckling was a contributing factor to the improvement in safety.Kenya, traffic, driving regulations, matatus, safety