The Hypanis Valles delta: The last highstand of a sea on early Mars?

One of the most contentious hypotheses in the geological history of Mars is whether the northern lowlands ever contained an oceanic water body. Arguably, the best evidence for an ocean comes from the presence of sedimentary fans around Mars' dichotomy boundary, which separates the northern lowlands from the southern highlands. Here we describe the palaeogeomorphology of the Hypanis Valles sediment fan, the largest sediment fan complex reported on Mars (area >970 km2). This has an extensive catchment (4.6 x 105 km2) incorporating Hypanis and Nanedi Valles, that we show was active during the late-Noachian/early-Hesperian period (∼3.7 Ga). The fan comprises a series of lobe-shaped sediment bodies, connected by multiple bifurcating flat-topped ridges. We interpret the latter as former fluvial channel belts now preserved in inverted relief. Meter-scale-thick, sub-horizontal layers that are continuous over tens of kilometres are visible in scarps and the inverted channel margins. The inverted channel branches and lobes are observed to occur up to at least 140 km from the outlet of Hypanis Valles and descend ∼500 m in elevation. The progressive basinward advance of the channellobe transition records deposition and avulsion at the margin of a retreating standing body of water, assuming the elevation of the northern plains basin floor is stable. We interpret the Hypanis sediment fan to represent an ancient delta as opposed to a fluvial fan system. At its location at the dichotomy boundary, the Hypanis Valles fan system is topographically open to Chryse Planitia – an extensive plain that opens in turn into the larger northern lowlands basin. We conclude that the observed progradation of fan bodies was due to basinward shoreline retreat of an ancient body of water which extended across at least Chryse Planitia. Given the open topography, it is plausible that the Hypanis fan system records the existence, last highstand, and retreat of a large sea in Chryse Planitia and perhaps even an ocean that filled the northern plains of Mars

Mars sample return – a proposed mission campaign whose time is now

The analysis in Earth laboratories of samples that could be returned from Mars is of extremely high interest to the international Mars exploration community. IMEWG (the International Mars Exploration Working Group) has been evaluating options, by means of a working group referred to as iMOST, to refine the scientific objectives of MSR. The Mars 2020 sample-caching rover mission is the first component of the Mars Sample Return campaign, so its existence constitutes a critical opportunity. Finally, on April 26, 2018, NASA and ESA signed a Statement of Intent to work together to formulate, by the end of 2019, a joint plan for the retrieval missions that are essential to the completion of the MSR Campaign. All of these converged April 25-27, 2018 in Berlin, Germany, at the 2nd International Mars Sample Return Conference

Discretionary sanctions and rewards in the repeated inspection game

We experimentally investigate a repeated “inspection game” where, in the stage game, an employee can either work or shirk and an employer simultaneously chooses to inspect or not inspect. The unique equilibrium of the stage game is in mixed strategies with positive probabilities of shirking/inspecting while combined payoffs are maximized when the employee works and the employer does not inspect. We examine the effects of allowing the employer discretion to sanction or reward the employee after observing stage game payoffs. When employers have limited discretion, and can only apply sanctions and/or rewards following an inspection, we find that both instruments are equally effective in reducing shirking and increasing joint earnings. When employers have discretion to reward and/or sanction independently of whether they inspect we find that rewards are more effective than sanctions. In treatments where employers can combine sanctions and rewards employers rely mainly on rewards and outcomes closely resemble those of treatments where only rewards are possible

Incomplete Punishment Networks in Public Goods Games: Experimental Evidence

Abundant evidence suggests that high levels of contributions to public goods can be sustained through self-governed monitoring and sanctioning. This experimental study investigates the effectiveness of decentralized sanctioning institutions in alternative punishment networks. Our results show that the structure of punishment network significantly affects allocations to the public good. In addition, we observe that network configurations are more important than punishment capacities for the levels of public good provision, imposed sanctions and economic efficiency. Lastly, we show that targeted revenge is a major driver of anti-social punishment

An amphitropic cAMP-binding protein in yeast mitochondria

ABSTRACT: We describe the first example of a mitochondrial protein with a covalently attached phos-phatidylinositol moiety acting as a membrane anchor. The protein can be metabolically labeled with both stearic acid and inositol. The stearic acid label is removed by phospholipase D whereupon the protein with the retained inositol label is released from the membrane. This protein is a cAMP receptor of the yeast Saccharomyces cereuisiae and tightly associated with the inner mitochondrial membrane. However, it is converted into a soluble form during incubation of isolated mitochondria with Ca2+ and phospholipid (or lipid derivatives). This transition requires the action of a proteinaceous, N-ethylmaleimide-sensitive component of the intermembrane space and is accompanied by a decrease in the lipophilicity of the cAMP receptor. We propose that the component of the intermembrane space triggers the amphitropic behavior of the mitochondrial lipid-modified CAMP-binding protein through a phospholipase activity. Only in recent years specific fatty acids have been recog-nized to play important roles in the association of proteins with membranes. Both noncovalent and covalent interactions be-tween fatty acids and proteins have been reported. Among the latter are GTP-binding proteins (Molenaar et al., 1988)

If cooperation is likely punish mildly: Insights from economic experiments based on the snowdrift game

Punishment may deter antisocial behavior. Yet to punish is costly, and the costs often do not offset the gains that are due to elevated levels of cooperation. However, the effectiveness of punishment depends not only on how costly it is, but also on the circumstances defining the social dilemma. Using the snowdrift game as the basis, we have conducted a series of economic experiments to determine whether severe punishment is more effective than mild punishment. We have observed that severe punishment is not necessarily more effective, even if the cost of punishment is identical in both cases. The benefits of severe punishment become evident only under extremely adverse conditions, when to cooperate is highly improbable in the absence of sanctions. If cooperation is likely, mild punishment is not less effective and leads to higher average payoffs, and is thus the much preferred alternative. Presented results suggest that the positive effects of punishment stem not only from imposed fines, but may also have a psychological background. Small fines can do wonders in motivating us to chose cooperation over defection, but without the paralyzing effect that may be brought about by large fines. The later should be utilized only when absolutely necessary.Comment: 15 pages, 6 figures; accepted for publication in PLoS ON

Benevolent characteristics promote cooperative behaviour among humans

Cooperation is fundamental to the evolution of human society. We regularly observe cooperative behaviour in everyday life and in controlled experiments with anonymous people, even though standard economic models predict that they should deviate from the collective interest and act so as to maximise their own individual payoff. However, there is typically heterogeneity across subjects: some may cooperate, while others may not. Since individual factors promoting cooperation could be used by institutions to indirectly prime cooperation, this heterogeneity raises the important question of who these cooperators are. We have conducted a series of experiments to study whether benevolence, defined as a unilateral act of paying a cost to increase the welfare of someone else beyond one's own, is related to cooperation in a subsequent one-shot anonymous Prisoner's dilemma. Contrary to the predictions of the widely used inequity aversion models, we find that benevolence does exist and a large majority of people behave this way. We also find benevolence to be correlated with cooperative behaviour. Finally, we show a causal link between benevolence and cooperation: priming people to think positively about benevolent behaviour makes them significantly more cooperative than priming them to think malevolently. Thus benevolent people exist and cooperate more

Technical boys and creative girls: the career aspirations of digitally-skilled youths

Digital technology is increasingly central to our lives, particularly among young people. However, there remains a concern from government and businesses of a digital skills gap because many youths, especially girls, tend to be consumers rather than creators of technology. Drawing on 32 semi-structured interviews with digitally-skilled teenagers (aged 13-19), we investigate their digital career aspirations and examine how identities and discourses of gender can interact with the type of digital careers that are of interest to these youths. While we found digitally-skilled young people still articulate traditional gendered discourses of digital competence, especially around technical abilities, we highlight the growing importance of creativity as a career pathway into digital technology. Implications of the findings are discussed in relation to the new computing curriculum in England, which prioritises technical computing skills, and the discontinuation of Information and Communications Technology (ICT), which facilitates a broader usage of software and digital productivity

Mars sample return – a proposed mission campaign whose time is now

The analysis in Earth laboratories of samples that could be returned from Mars is of extremely high interest to the international Mars exploration community. IMEWG (the International Mars Exploration Working Group) has been evaluating options, by means of a working group referred to as iMOST, to refine the scientific objectives of MSR. The Mars 2020 sample-caching rover mission is the first component of the Mars Sample Return campaign, so its existence constitutes a critical opportunity. Finally, on April 26, 2018, NASA and ESA signed a Statement of Intent to work together to formulate, by the end of 2019, a joint plan for the retrieval missions that are essential to the completion of the MSR Campaign. All of these converged April 25-27, 2018 in Berlin, Germany, at the 2nd International Mars Sample Return Conference