Hydrodynamic correlation functions of a driven granular fluid in steady state

We study a homogeneously driven granular fluid of hard spheres at intermediate volume fractions and focus on time-delayed correlation functions in the stationary state. Inelastic collisions are modeled by incomplete normal restitution, allowing for efficient simulations with an event-driven algorithm. The incoherent scattering function Fincoh(q,t ) is seen to follow time-density superposition with a relaxation time that increases significantly as the volume fraction increases. The statistics of particle displacements is approximately Gaussian. For the coherent scattering function S(q,ω), we compare our results to the predictions of generalized fluctuating hydrodynamics, which takes into account that temperature fluctuations decay either diffusively or with a finite relaxation rate, depending on wave number and inelasticity. For sufficiently small wave number q we observe sound waves in the coherent scattering function S(q,ω) and the longitudinal current correlation function Cl(q,ω). We determine the speed of sound and the transport coefficients and compare them to the results of kinetic theory.

Relationships Past and Present: Examining the Impact of One's Relationship with His/her Opposite-sex Parent on His/her Attitudes Toward and Engagement in Hookup Culture

Hooking up has become a common and public practice on university campuses across the country. While much research has determined who is doing it, with whom they are doing it, and what they are hoping to get out of it, little work has been done to determine what personal factors motivate students to participate in the culture. A total of 407 current students were surveyed to assess the impact of one’s relationship with his/her opposite-sex parent on his/her attitudestoward and engagement in hookup culture on campus. Scores were assigned to the participants to divide them into categories of high and low attachment with their parent. It was hypothesizedthat heterosexual students who do not perceive themselves as having a strong, close, positive relationship with their opposite-sex parent would be more likely to engage in or attempt to engage in casual sexual behavior. This pattern was expected to be strongest for women on campus. Men and women differed in their reasons for hooking up, with whom they hook up, to what they attribute the behaviors of their peers, and what they hope to gain from their sexual interactions. Effects of parent-child relationships were significant only for women who reported hooking up because “others are doing it,” men’s agreement with the behavior of their peers, and women’s overall satisfaction with their hookups. Developmental, social, and evolutionary perspectives are employed to explain the results. University status was determined to be most telling of the extent to which a student is engaged in hookup culture.