Reaction kinetics on clusters and islands

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70583/2/JCPSA6-85-11-6804-1.pd

Localized In‐Band Rotational Phonons in Mixed Molecular Crystals: Electronic Spectra of Naphthalene Doped Biphenyl and Durene

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70064/2/JCPSA6-56-7-3716-1.pd

Slipping friction of an optically and magnetically manipulated microsphere rolling at a glass-water interface

The motion of submerged magnetic microspheres rolling at a glass-water interface has been studied using magnetic rotation and optical tweezers combined with bright-field microscopy particle tracking techniques. Individual microspheres of varying surface roughness were magnetically rotated both in and out of an optical trap to induce rolling, along either plain glass cover slides or glass cover slides functionalized with polyethylene glycol. It has been observed that the manipulated microspheres exhibited nonlinear dynamic rolling-while-slipping motion characterized by two motional regimes: At low rotational frequencies, the speed of microspheres free-rolling along the surface increased proportionately with magnetic rotation rate; however, a further increase in the rotation frequency beyond a certain threshold revealed a sharp transition to a motion in which the microspheres slipped with respect to the external magnetic field resulting in decreased rolling speeds. The effects of surface-microsphere interactions on the position of this threshold frequency are posed and investigated. Similar experiments with microspheres rolling while slipping in an optical trap showed congruent results.Comment: submitted to Journal of Applied Physics, 11 figure

Biased Social Perceptions of Knowledge: Implications for Negotiators' Rapport and Egocentrism

This study examines how people manage uncertain competitive social interactions. To achieve positive interaction outcomes, individuals may engage in a social perception process that leads them to believe they have obtained more information about others than these others gained about them. We investigate how asymmetric knowledge perceptions contribute to important aspects of negotiation, namely rapport building among strangers and egocentric beliefs about fairness of resource distribution. In Study 1, dyads completed measures of knowledge acquisition and partner evaluation after a rapport‐building exercise. Results showed that individuals believed they gained more information about their partner than vice versa; notably, the magnitude of this knowledge bias was associated with more positive partner evaluations. Study 2 showed that the magnitude of the knowledge bias predicted lower egocentrism in a commons dilemma task. Together, these results suggest knowledge asymmetries facilitate rapport among strangers and may have important implications for cooperation in competitive negotiation settings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111124/1/ncmr12047.pd

Mentalizing the body: spatial and social cognition in anosognosia for hemiplegia

Following right-hemisphere damage, a specific disorder of motor awareness can occur called anosognosia for hemiplegia, i.e. the denial of motor deficits contralateral to a brain lesion. The study of anosognosia can offer unique insights into the neurocognitive basis of awareness. Typically, however, awareness is assessed as a first person judgement and the ability of patients to think about their bodies in more ‘objective’ (third person) terms is not directly assessed. This may be important as right-hemisphere spatial abilities may underlie our ability to take third person perspectives. This possibility was assessed for the first time in the present study. We investigated third person perspective taking using both visuospatial and verbal tasks in right-hemisphere stroke patients with anosognosia ( n = 15) and without anosognosia ( n = 15), as well as neurologically healthy control subjects ( n = 15). The anosognosic group performed worse than both control groups when having to perform the tasks from a third versus a first person perspective. Individual analysis further revealed a classical dissociation between most anosognosic patients and control subjects in mental (but not visuospatial) third person perspective taking abilities. Finally, the severity of unawareness in anosognosia patients was correlated to greater impairments in such third person, mental perspective taking abilities (but not visuospatial perspective taking). In voxel-based lesion mapping we also identified the lesion sites linked with such deficits, including some brain areas previously associated with inhibition, perspective taking and mentalizing, such as the inferior and middle frontal gyri, as well as the supramarginal and superior temporal gyri. These results suggest that neurocognitive deficits in mental perspective taking may contribute to anosognosia and provide novel insights regarding the relation between self-awareness and social cognition

Fractal exciton fusion: Simulations on long-range percolation clusters

Computer simulations of exciton fusion on percolating clusters were performed for interaction distances N=2, 3, and 4. The data yield slopes less than those expected from superuniversality (f=2/3) at interaction distances above 2, when the probability of sucessively longer hops falls by a factor of 1/10.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24627/1/0000037.pd

Exciton transport in naphthalene alloys: A transition from percolation to diffusion

Steady-state singlet excitation transport in ternary naphthalene crystals (C10H8/C10D8/[beta]-methylnaphthalene) fits diffusion models at 4.2 K, but not at 1.8 K, where it fits a percolation model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23773/1/0000009.pd

Non-beneficial pediatric research : individual and social interests

Biomedical research involving human subjects is an arena of conflicts of interests. One of the most important conflicts is between interests of participants and interests of future patients. Legal regulations and ethical guidelines are instruments designed to help find a fair balance between risks and burdens taken by research subjects and development of knowledge and new treatment. There is an universally accepted ethical principle, which states that it is not ethically allowed to sacrifice individual interests for the sake of society and science. This is the principle of precedence of individual. But there is a problem with how to interpret the principle of precedence of individual in the context of research without prospect of future benefit involving children. There are proposals trying to reconcile non-beneficial research involving children with the concept of the best interests. We assert that this reconciliation is flawed and propose an interpretation of the principle of precedence of individual as follows: not all, but only the most important interests of participants, must be guaranteed; this principle should be interpreted as the secure participant standard. In consequence, the issue of permissible risk ceiling becomes ethically crucial in research with incompetent subjects

Dynamic Scaling of an Adsorption-Diffusion Process on Fractals

A dynamic scaling of a diffusion process involving the Langmuir type adsorption is studied. We find dynamic scaling functions in one and two dimensions and compare them with direct numerical simulations, and we further study the dynamic scaling law on fractal surfaces. The adsorption-diffusion process obeys the fracton dynamics on the fractal surfaces.Comment: 9 pages, 7 figure