20,977 research outputs found
Leadership and self-enforcing international environmental agreements with non-negative emissions
For the widely-used linear-quadratic model of stable IEAs the key results are: (i) if the members of the IEA act in a Cournot fashion with respect to non-signatories, a stable IEA has no more than 2 signatories; (ii) if the signatories act as Stackelberg leaders, a stable IEA can have any number of signatories. These results were derived using numerical simulations and ignored the non-negativity constraint on emissions. Recent papers using analytical approaches and explicitly recognising the non-negativity constraint have suggested that with Stackelberg leadership a stable IEA has at most four signatories. Such papers have introduced non-negativity constraints by restricting parameter values to ensure interior solutions for emissions, which restricts the number of signatories. We use the more appropriate approach of directly imposing the non-negativity constraint on emissions, recognising that for some parameter values this will entail corner solutions, and show, analytically, that the key results from the literature go through
Exposure to political disparagement humor and its impact on trust in politicians: How long does it last?
Indexación: Scopus.The experimental research that looks into the effects of political humor on an individual's attitudes toward politics and politicians does not evaluate its long-term effects. With this in mind, this study aims to determine the possible effects that being exposed to humor which belittles politicians may have on an ordinary citizen's trust in them, while at the same time it observes the possible effects that such exposure has on them and the time such effects last. Two hypotheses were tested. The first one was that humor involves less cognitive elaboration, which leads to a short-term impact on the perception of the individual. The second one was that the repetition of a message can augment the swing of such message. Also, a series of elements regarding disposition toward politicians and political affiliation were considered. Two experiments were designed. The first experiment, (N = 94), considered three groups: one exposed to political disparagement humor; one control group exposed to disparagement humor against non-politician subjects; and a control group exposed to a non-humorous political video. Trust in politicians was evaluated first at baseline, then immediately after the experimental manipulation, and once again a week after the experimental manipulation had happened. In the second experiment (N = 146), participants were randomly assigned to one experimental and two control groups. The trust in politicians of the three groups was estimated and they were sent political cartoons, non-political cartoons, and newspaper headlines regarding political topics twice a day for a week via WhatsApp. Trust in politicians among the three groups was assessed again after 1 week, and for a third time 1 week after that. As a result, it was observed that a one-off exposure to political disparagement humor affects trust in politicians negatively; however, the effect it attains is short-lived and can be explained through the political content of the item and not only humor. Also, being exposed to cartoons constantly for a week had no impact whatsoever on the way politics and politicians were perceived during the time the experiment was carried out. Possible explanations for these findings are discussed.https://www.frontiersin.org/articles/10.3389/fpsyg.2017.02236/ful
Leadership and self-enforcing international environmental agreements with non-negative emissions
For the widely-used linear-quadratic model of stable IEAs the key results are: (i) if the members of the IEA act in a Cournot fashion with respect to non-signatories, a stable IEA has no more than 2 signatories; (ii) if the signatories act as Stackelberg leaders, a stable IEA can have any number of signatories. These results were derived using numerical simulations and ignored the non-negativity constraint on emissions. Recent papers using analytical approaches and explicitly recognising the non-negativity constraint have suggested that with Stackelberg leadership a stable IEA has at most four signatories. Such papers have introduced non-negativity constraints by restricting parameter values to ensure interior solutions for emissions, which restricts the number of signatories. We use the more appropriate approach of directly imposing the non-negativity constraint on emissions, recognising that for some parameter values this will entail corner solutions, and show, analytically, that the key results from the literature go through.
Computing spectral sequences
In this paper, a set of programs enhancing the Kenzo system is presented.
Kenzo is a Common Lisp program designed for computing in Algebraic Topology, in
particular it allows the user to calculate homology and homotopy groups of
complicated spaces. The new programs presented here entirely compute Serre and
Eilenberg-Moore spectral sequences, in particular the groups and differential
maps for arbitrary r. They also determine when the spectral sequence has
converged and describe the filtration of the target homology groups induced by
the spectral sequence
Electronic structure of polychiral carbon nanotubes
Most of the works devoted so far to the electronic band structure of
multiwall nanotubes have been restricted to the case where the individual
layers have the same helicity. By comparison, much less is known on the
electronic properties of multiwall nanotubes that mix different helicities.
These are interesting systems, however, since they can be composed of both
metallic and semiconducting layers. For the present work, tight-binding
calculations were undertaken for polychiral two-layer nanotubes such as
(9,6)@(15,10), (6,6)@(18,2), and others. The recursion technique was used to
investigate how the densities of states of the individual layers are affected
by the intertube coupling. Constant-current STM images were also calculated for
these systems. The result obtained is that the image of a two-wall nanotube is
pretty much the same as the one of the isolated external layer. It is only in
the case of monochiral, commensurate structures like (5,5)@(10,10) that
interlayer effects can be seen on the STM topography.Comment: 12 pages plus 6 figures included in the postscript fil
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