All-pay auctions with resale

We study equilibria of first- and second-price all-pay auctions with resale when players’ signals are affiliated and symmetrically distributed. We show that existence of resale possibilities introduces an endogenous element to players’ valuations and creates a signaling incentive for players. We characterize symmetric bidding equilibria for both firstand second-price all-pay auctions with resale and provide sufficient conditions for existence of symmetric equilibria. Under our conditions we show that second-price all-pay auctions generate no less expected revenue than first-price all-pay auctions with resale. The initial seller could benefit from publicly disclosing his private information which is affiliated with players’ signals.all-pay auction, resale

A study of the high-inclination population in the Kuiper belt - II. The Twotinos

As the second part of our study, in this paper we proceed to explore the dynamics of the high-inclination Twotinos in the 1:2 Neptune mean motion resonance (NMMR). Depending on the inclination $i$, we show the existence of two critical eccentricities $e_a(i)$ and $e_c(i)$, which are lower limits of the eccentricity $e$ for the resonant angle $\sigma$ to exhibit libration and asymmetric libration, respectively. Accordingly, we have determined the libration centres $\sigma_0$ for inclined orbits, which are strongly dependent on $i$. With initial $\sigma=\sigma_0$ on a fine grid of $(e, i)$, the stability of orbits in the 1:2 NMMR is probed by 4-Gyr integrations. It is shown that symmetric librators are totally unstable for $i\ge30^{\circ}$; while stable asymmetric librators exist for $i$ up to $90^{\circ}$. We further investigate the 1:2 NMMR capture and retention of planetesimals with initial inclinations $i_0\le90^{\circ}$ in the planet migration model using a time-scale of $2\times10^7$ yr. We find that: (1) the capture efficiency of the 1:2 NMMR decreases drastically with the increase of $i_0$, and it goes to 0 when $i_0\ge60^{\circ}$; (2) the probability of discovering Twotinos with $i>25^{\circ}$, beyond observed values, is roughly estimated to be $\le0.1$ per cent; (3) more particles are captured into the leading rather than the trailing asymmetric resonance for $i_0\le10^{\circ}$, but this number difference appears to be the opposite at $i_0=20^{\circ}$ and is continuously varying for even larger $i_0$; (4) captured Twotinos residing in the trailing resonance or having $i>15^{\circ}$ are practically outside the Kozai mechanism, like currently observed samples.Comment: 13 pages, 10 figures, Accepted by MNRAS. Comments welcome

Formation and transformation of the 3:1 mean-motion resonance in 55 Cancri System

We report in this paper the numerical simulations of the capture into the 3:1 mean-motion resonance between the planet b and c in the 55 Cancri system. The results show that this resonance can be obtained by a differential planetary migration. The moderate initial eccentricities, relatively slower migration and suitable eccentricity damping rate increase significantly the probability of being trapped in this resonance. Otherwise, the system crosses the 3:1 commensurability avoiding resonance capture, to be eventually captured into a 2:1 resonance or some other higher-order resonances. After the resonance capture, the system could jump from one orbital configuration to another one if the migration continues, making a large region of the configuration space accessible for a resonance system. These investigations help us understand the diversity of resonance configurations and put some constrains on the early dynamical evolution of orbits in the extra-solar planetary systems.Comment: 6 pages with 2 figures. Submitted for publication in the proceedings of IAU Symposium No.249. A paper telling much more details than this paper is under preparin

THREE ESSAYS ON AUCTION THEORY AND CONTEST THEORY

In the first chapter, ¡°All-Pay Auctions with Resale¡±, I study equilibria of first- and second-price all-pay auctions with resale when players' signals are affiliated and symmetrically distributed. I show that existence of resale possibilities introduces an endogenous element to players' valuations and creates a signaling incentive for players. I characterize symmetric bidding equilibria for both first- and second-price all-pay auctions with resale and provide sufficient conditions for existence of symmetric equilibria. Under those conditions I show that second-price all-pay auctions generate no less expected revenue than first-price all-pay auctions with resale. The initial seller could benefit from publicly disclosing her private information which is affiliated with players' signals.Outcome in all-pay auctions is deterministic since the highest bidder wins the prize with probability one. However, many realistic contests have in-deterministic outcome and no player can guarantee winning the prize. The second chapter, ¡°Rent-Seeking Contest with Private Values and Resale¡±, studies rent-seeking contests with private values and resale possibilities. With an in-deterministic success function, the resulting possible inefficiency creates a motive for aftermarket trade. Players' valuations are endogenously determined when there is an opportunity of resale. I characterize symmetric equilibria. I assume that the winner has full bargaining power; however, the results extend to other resale mechanisms. I show that resale enhances allocative efficiency ex post at the expense of more wasted social resources since players compete more aggressively with resale possibilities.In the third chapter, ¡°The Imperfectly Discriminating Contests with Incomplete Information¡±, I study the existence of monotone pure-strategy equilibria in imperfectly discriminating contests with incomplete information. Sufficient conditions under which equilibria exist are provided for both finite-action and continuum-action cases. Using a two-bidder example, we derive some properties of equilibria and show a special case of revenue equivalence between contests with incomplete information and contests with complete information

Rent seeking contests with private values and resale

Abstract This paper studies rent-seeking contests with private values and resale possibilities. With a stochastic success function, the resulting possible inefficiency creates a motive for aftermarket trade. Players' valuations are endogenously determined when there is an opportunity of resale. We characterize symmetric equilibria. We assume that the winner has full bargaining power, however, the results extend to other resale mechanisms. We show that resale enhances allocative efficiency ex post at the expense of more wasted social resources since players compete more aggressively with resale possibilities

All-pay auctions with resale

We study equilibria of first- and second-price all-pay auctions with resale when players’ signals are affiliated and symmetrically distributed. We show that existence of resale possibilities introduces an endogenous element to players’ valuations and creates a signaling incentive for players. We characterize symmetric bidding equilibria for both firstand second-price all-pay auctions with resale and provide sufficient conditions for existence of symmetric equilibria. Under our conditions we show that second-price all-pay auctions generate no less expected revenue than first-price all-pay auctions with resale. The initial seller could benefit from publicly disclosing his private information which is affiliated with players’ signals

All-pay auctions with resale

We study equilibria of first- and second-price all-pay auctions with resale when players’ signals are affiliated and symmetrically distributed. We show that existence of resale possibilities introduces an endogenous element to players’ valuations and creates a signaling incentive for players. We characterize symmetric bidding equilibria for both firstand second-price all-pay auctions with resale and provide sufficient conditions for existence of symmetric equilibria. Under our conditions we show that second-price all-pay auctions generate no less expected revenue than first-price all-pay auctions with resale. The initial seller could benefit from publicly disclosing his private information which is affiliated with players’ signals

Religiosity and Risky Sexual Behavior Among Adolescents in Sarawak, Malaysia

Introduction: Risky sexual behavior is defined as a behavior that increases one’s risk of contracting or being infected by sexually transmitted infections (STIs) and experiencing unintended pregnancies. This study examined the relationship between religiosity and risky sexual behavior among adolescents in the state of Sarawak, Malaysia. Methods: The inclusion criteria included 1,146 unmarried adolescents aged between 16 and 19 years, whereby they answered a validated self-administered questionnaire using the modified Religion Scale and Risky Sexual Behavior – Unsafe Sex Scale. The analysis was restricted to respondents who reported to have had sex. Results: Overall, the response rate recorded 95% (n=1,086), whereby the prevalence of respondents who reported that they have had sex was 9.5%, n=103 (71 males, 32 females, mean age 17.82). Descriptive results further showed that the prevalence of those who have had sex for male and female were 6.53% and 2.94%, respectively. The earliest sexual debut was revealed to be at 13 years of age. Moreover, bivariate analyses indicated a significant and negative correlation between religious practice and risky sexual behavior (r= -.23; p<.05). Conclusion: The study revealed that religious adolescents are more likely to avoid risky sexual behavior. This means that religious practice may become a potential protective factor in influencing adolescents to avoid risky sexual behaviors. (Abstract by authors