Do side payments help? Collective decisions and strategic delegation

I investigate when a exible bargaining agenda, where side payments are possible, facilitates cooperation in a context with strategic delegation. On the one hand, allowing side payments may be necessary when one partys participation constraint otherwise would be violated. On the other, with side payments each principal appoints a delegate that values the project less, since this increases her bargaining power. Reluctant agents, in turn, implement too few projects. I show that side payments are bad if the heterogeneity is small while the uncertainty and the typical value of the project are large. With a larger number of parties there may be a stalemate without side payments, but delegation becomes more strategic as well, and cooperation decreases in either case.Collective action, side transfers, bargaining agenda, strategic delegation, issue linkages

Flexible Integration

For a club such as the European Union, an important question is when, and under which conditions, a subset of the members should be allowed to form "inner clubs" and enhance cooperation. Flexible cooperation allows members to participate if and only if they benefit, but it generates a freerider problem if potential members choose to opt out. The analysis shows that flexible cooperation is better if the heterogeneity is large and the externality small. The best possible symmetric and monotonic participation mechanism, however, is implemented by two thresholds: A mandatory and a minimum participation rule. Rigid and flexible cooperation are both special cases of this mechanism. For each of these thresholds, the optimum is characterized.

Random Permutation Statistics and An Improved Slide-Determine Attack on KeeLoq

KeeLoq is a lightweight block cipher which is extensively used in the automotive industry. Its periodic structure, and overall simplicity makes it vulnerable to many different attacks. Only certain attacks are considered as really "practical" attacks on KeeLoq: the brute force, and several other attacks which require up to 2p16 known plaintexts and are then much faster than brute force, developed by Courtois et al., and (faster attack) by Dunkelman et al. On the other hand, due to the unusually small block size, there are yet many other attacks on KeeLoq, which require the knowledge of as much as about 2p32 known plaintexts but are much faster still. There are many scenarios in which such attacks are of practical interest, for example if a master key can be recovered, see Section 2 in [11] for a detailed discussion. The fastest of these attacks is an attack by Courtois, Bard and Wagner from that has a very low complexity of about 2p28 KeeLoq encryptions on average. In this paper we will propose an improved and refined attack which is faster both on average and in the best case. We also present an exact mathematical analysis of probabilities that arise in these attacks using the methods of modern analytic combinatorics

On the role of system size in Hall MHD magnetic reconnection

We study the effects of the Hall electric field on magnetic island coalescence in the large island limit and find evidence for both a elongated electron current sheet layer with a Sweet-Parker-like reconnection rate and a collapsed, Petschek-like electron sheet with a peak reconnection rate approaching the 0.1 vA B0 Hall MHD rate. The state observed in our simulations appears to depend on grid scale. Furthermore, even at the largest system sizes, we find that flux-pileup effects cause the islands to "bounce" despite the presence of a collapsed current sheet allowing for fast instantaneous reconnection. The average reconnection rate in the large island limit is slow though the peak reconnection rate is fast.Comment: Submitted to PRL; 5 pages, 7 figure

Scalar Reduction of a Neural Field Model with Spike Frequency Adaptation

We study a deterministic version of a one- and two-dimensional attractor neural network model of hippocampal activity first studied by Itskov et al 2011. We analyze the dynamics of the system on the ring and torus domain with an even periodized weight matrix, assum- ing weak and slow spike frequency adaptation and a weak stationary input current. On these domains, we find transitions from spatially localized stationary solutions ("bumps") to (periodically modulated) solutions ("sloshers"), as well as constant and non-constant velocity traveling bumps depending on the relative strength of external input current and adaptation. The weak and slow adaptation allows for a reduction of the system from a distributed partial integro-differential equation to a system of scalar Volterra integro-differential equations describing the movement of the centroid of the bump solution. Using this reduction, we show that on both domains, sloshing solutions arise through an Andronov-Hopf bifurcation and derive a normal form for the Hopf bifurcation on the ring. We also show existence and stability of constant velocity solutions on both domains using Evans functions. In contrast to existing studies, we assume a general weight matrix of Mexican-hat type in addition to a smooth firing rate function.Comment: 60 pages, 22 figure

Alaska Natives and American Laws

In this thesis we focus on the issue of crowdfunding and especially how a project relates to and embraces its community. While a lot of related research focus on what makes people give, our research instead delve into whether a creator looks upon the sponsors as something more than just a financial resource. To manage this task we used a triangular perspective consisting of a case study, a questionnaire and a netnographic study. The goal was to gain the perspectives of creators, crowdfunding platforms and sponsors on how the communication between the community and the project works and can be improved.        The three crowdfunding platforms we reviewed (Kickstarter, IndieGoGo, Rockethub) all had fairly similar models on how to attract sponsors and make them involved in the project, while the questionnaire and netnographic study demonstrated how a community could contribute in different ways. Based on our results we draw the conclusion that a project can be successful without embracing the creative qualities of its sponsors but doing so also is a waste of a great asset to both current and future projects.

Synthesis and Characterization of Luminescent Lanthanide Nano-Rings

It is not uncommon for inorganic chemistry classes to gloss over the chemistry of the lanthanides. Because most inorganic chemists work closely with the d -electrons of the transition metals, the shielded and inert f -electrons of the lanthanides may at first glance seem monotone or even boring. However, to truly appreciate the lanthanides and the complexes they produce, one must come to embrace their chemical simplicity and understand their much more interesting electronic properties that lead to extremely interesting luminescent and magnetic molecules. Furthermore, though the lanthanides generally only form 3+ ions, it is important to consider that their high coordination number can lead to some very large and unusual molecular structures. Additionally, lanthanide complexes are known for their photophysical properties, specifi cally their sharp emission peaks. This, along with the fact that they don't photobleach and are relatively nontoxic, make them ideal for biological probes. If the ligand in the complex can be functionalized to couple with an antibody, the complex should then be able to follow the antibody wherever it goes, for example, to a cancerous tumor, and the probes would then aggregate in the area, causing localized luminescence, aiding in early detection of cancer. This thesis reports the synthesis of a 42-nuclear lanthanide nano-ring: likely the highest nuclearity lanthanide complex ever produced. This complex, referred to as Ln 42, is produced by reacting an ortho-vanillin based ligand with lanthanide acetate, the suitable lanthanides being gadolinium, terbium, dysprosium, and holmium. The complex self-assembles, interestingly, fi rst hydrolyzing the ligand such that the only portion that remains in the final complex is deprotonated ortho-vanillin. Acetate and hydroxyl groups also remain in the final complex, in addition to the lanthanide centers. The structure in the crystalline solid state was determined using single crystal X-ray diffraction.Chemistr