Privately informed parties and policy divergence

This paper presents a Downsian model of political competition in which parties have incomplete but richer information than voters on policy effects. Each party can observe a private signal of the policy effects, while voters cannot. In this setting, voters infer the policy effects from the party platforms. In this political game with private information, we show that there exist weak perfect Bayesian equilibria (WPBEs) at which the parties play different strategies, and thus, announce different platforms even when their signals coincide. This result is in contrast with the conclusion of the Median Voter Theorem in the classical Downsian model. Our equilibrium analysis suggests similarity between the set of WPBEs in this model and the set of uniformly perfect equilibria of Harsanyi and Selten (1988) in the model with completely informed parties which we studied in a previous paper (Kikuchi, 2010).

Multidimensional Political Competition with Non-Common Beliefs

This paper extends a probabilistic voting model with a multidimensional policy space, allowing candidates to have different prior probability distributions of the distribution of voters' ideal policies. In this model, we show that a platform pair is a Nash equilibrium if and only if both candidates choose a common generalized median of expected ideal policies. Thus, the existence of a Nash equilibrium requires not only that each candidate's belief have an expected generalized median, which is already a knife-edge condition, but also that the two medians coincide. We also study limits of ε-equilibria of Radner (1980) as ε → 0, which we call "limit equilibria." Limit equilibria are policy pairs that approximate choices by the candidates who almost perfectly optimize. We show that a policy pair is a limit equilibrium if and only if both candidates choose the same policy around which they form "opposite expectations" in a certain sense. For a limit equilibrium to exist (equivalently, for ε-equilibria to exist for all ε > 0), it is sufficient, though not necessary, that either candidate has an expected generalized median.

Downsian Model with Asymmetric Information: Possibility of Policy Divergence

This paper presents a model of Downsian political competition in which voters are imperfectly informed about economic fundamentals. In this setting, parties' choices of platforms influence voters' behavior not only through voters' preferences over policies, but also through formation of their expectation on the unknown fundamentals. We show that there exist pure-strategy equilibria in this political game with asymmetric information at which the two parties' policies diverge with positive probability. This result is in contrast with the well-known median voter theorem in the classical model of Downsian competition. We also study refinement of equilibria, and identify the perfect equilibria (Selten, 1975) and the strictly perfect equilibria (Okada, 1981). The Nash equilibria with the strongest asymmetry in the parties' strategies are proved to be strictly perfect.

Welfare ordering of voting weight allocations

This paper studies the allocation of voting weights in a committee representing groups of different sizes. We introduce a partial ordering of weight allocations based on stochastic comparison of social welfare. We show that when the number of groups is sufficiently large, this ordering asymptotically coincides with the total ordering induced by the cosine proportionality between the weights and the group sizes. A corollary is that a class of expectation-form objective functions, including expected welfare, the mean majority deficit and the probability of inversions, are asymptotically monotone in the cosine proportionality

Downsian Model with Asymmetric Information: Possibility of Policy Divergence

This paper presents a model of Downsian political competition in which voters are imperfectly informed about economic fundamentals. In this setting, partiesfchoices of platforms influence votersf behavior not only through votersf preferences over policies, but also through formation of their expectation on the unknown fundamentals. We show that there exist pure-strategy equilibria in this political game with asymmetric information at which the two partiesf policies diverge with positive probability. This result is in contrast with the well-known median voter theorem in the classical model of Downsian competition. We also study refinement of equilibria, and identify the perfect equilibria (Selten, 1975) and the strictly perfect equilibria (Okada, 1981). The Nash equilibria with the strongest asymmetry in the partiesf strategies are proved to be strictly perfect.

Leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent regeneration

n animal regeneration, control of position-dependent cell proliferation is crucial for the complete restoration of patterned appendages in terms of both, shape and size. However, detailed mechanisms of this process are largely unknown. In this study, we identified leucine/glutamine and v-ATPase/lysosomal acidification, via mechanistic target of rapamycin complex 1 (mTORC1) activation, as effectors of amputation plane-dependent zebrafish caudal fin regeneration. mTORC1 activation, which functions in cell proliferation, was regulated by lysosomal acidification possibly via v-ATPase activity at 3 h post amputation (hpa). Inhibition of lysosomal acidification resulted in reduced growth factor-related gene expression and suppression of blastema formation at 24 and 48 hpa, respectively. Along the proximal-distal axis, position-dependent lysosomal acidification and mTORC1 activation were observed from 3 hpa. We also report that Slc7a5 (L-type amino acid transporter), whose gene expression is position-dependent, is necessary for mTORC1 activation upstream of lysosomal acidification during fin regeneration. Furthermore, treatment with leucine and glutamine, for both proximal and distal fin stumps, led to an up-regulation in cell proliferation via mTORC1 activation, indicating that leucine/glutamine signaling possesses the ability to change the position-dependent regeneration. Our findings reveal that leucine/glutamine and v-ATPase/lysosomal acidification via mTORC1 activation are required for position-dependent zebrafish fin regeneration.This study was supported by grants from Grant-in-Aid for Scientific Research from the JSPS (KAKENHI JP15J05983) to K.T

Development of elliptic core-shell nanoparticles with fluorinated surfactants for ¹⁹F MRI

Wu Y., Minoshima M., Kikuchi K.. Development of elliptic core-shell nanoparticles with fluorinated surfactants for ¹⁹F MRI. Frontiers in Chemistry 12, 1408509 (2024); https://doi.org/10.3389/fchem.2024.1408509.Perfluorocarbon-encapsulated silica nanoparticles possess attractive features such as biological inertness and favorable colloidal properties for bioimaging with fluorine magnetic resonance imaging (¹⁹F MRI). Herein, a series of elliptic shaped silica nanoparticles with perfluorocarbon liquid perfluoro-15-crown-5 ether as core (PFCE@SiO₂) were synthesized using fluorinated surfactants N-(perfluorononylmethyl)-N,N,N-trimethylammonium chloride (C10-TAC) and N-(perfluoroheptylmethyl)-N,N,N-trimethylammonium chloride (C8-TAC). The nanoparticles are characterized to obtain elliptic core-shell structures. PFCE@SiO₂ showed strong ¹⁹F NMR signals of the encapsulated PFCE, indicating the potential as a highly sensitive ¹⁹F MRI probe. These elliptic PFCE@SiO₂ nanoparticles provide a new option of ¹⁹F MRI probe with a morphology different from conventional nanospheres

On-Orbit Demonstration of the Water Resistojet Propulsion System on Commercial 6U-Sat SPHERE-1 EYE

SPHERE-1 EYE, a 6U CubeSat developed by Sony Group Corporation, was launched at the beginning of 2023. The satellite included a water resistojet propulsion system, which is designed for orbit raising after the initial checkout. The water resistojet propulsion system consists of a tank, a vaporizer, nozzles, a control board, and a power processing unit. The form factor of the propulsion system is 1.25 U, the wet mass is 1.4 kg, and the achievable total impulse of the system is 170 Ns or higher. A unique design of the water propulsion system is a vaporization chamber generating steam at room temperature and low pressure, under 10 kPa. The performance measured on the ground shows a thrust of 2.7 mN, and a specific impulse of 60 s. A qualification test campaign including vibration, shock, thermal, throughput, and system performance tests was conducted, followed by acceptance tests. On-orbit demonstration was conducted on March 3rd and 16th for all four nozzles and the thrust generation was confirmed. The estimated thrust on orbit was 6.1 - 7.2 mN. Comparison between the on-orbit results and the ground tests demonstrated the functionality of the system as anticipated