Universal Non-Debye Scaling in the Density of States of Amorphous Solids.

At the jamming transition, amorphous packings are known to display anomalous vibrational modes with a density of states (DOS) that remains constant at low frequency. The scaling of the DOS at higher packing fractions remains, however, unclear. One might expect to find a simple Debye scaling, but recent results from effective medium theory and the exact solution of mean-field models both predict an anomalous, non-Debye scaling. Being mean-field in nature, however, these solutions are only strictly valid in the limit of infinite spatial dimension, and it is unclear what value they have for finite-dimensional systems. Here, we study packings of soft spheres in dimensions 3 through 7 and find, away from jamming, a universal non-Debye scaling of the DOS that is consistent with the mean-field predictions. We also consider how the soft mode participation ratio evolves as dimension increases.

Adaptive Mixture Modelling Metropolis Methods for Bayesian Analysis of Non-linear State-Space Models.

We describe a strategy for Markov chain Monte Carlo analysis of non-linear, non-Gaussian state-space models involving batch analysis for inference on dynamic, latent state variables and fixed model parameters. The key innovation is a Metropolis-Hastings method for the time series of state variables based on sequential approximation of filtering and smoothing densities using normal mixtures. These mixtures are propagated through the non-linearities using an accurate, local mixture approximation method, and we use a regenerating procedure to deal with potential degeneracy of mixture components. This provides accurate, direct approximations to sequential filtering and retrospective smoothing distributions, and hence a useful construction of global Metropolis proposal distributions for simulation of posteriors for the set of states. This analysis is embedded within a Gibbs sampler to include uncertain fixed parameters. We give an example motivated by an application in systems biology. Supplemental materials provide an example based on a stochastic volatility model as well as MATLAB code.

Identification of beta-adrenergic receptors in human lymphocytes by (-) (3H) alprenolol binding.

Human lymphocytes are known to posessess a catecholamine-responsive adenylate cyclase which has typical beta-adrenergic specificity. To identify directly and to quantitate these beta-adenergic receptors in human lymphocytes, (-) [3H] alprenolol, a potent beta-adrenergic antagonist, was used to label binding sites in homogenates of human mononuclear leukocytes. Binding of (-) [3H] alprenolol to these sites demonstrated the kinetics, affinity, and stereospecificity expected of binding to adenylate cyclase-coupled beta-adrenergic receptors. Binding was rapid (t1/2 less than 30 s) and rapidly reversible (t1/2 less than 3 min) at 37 degrees C. Binding was a saturable process with 75 +/- 12 fmol (-) [3H] alprenolol bound/mg protein (mean +/- SEM) at saturation, corresponding to about 2,000 sites/cell. Half-maximal saturation occurred at 10 nM (-) [3H] alprenolol, which provides an estimate of the dissociation constant of (-) [3H] alprenolol for the beta-adrenergic receptor. The beta-adrenergic antagonist, (-) propranolol, potently competed for the binding sites, causing half-maximal inhibition of binding at 9 nM. beta-Adrenergic agonists also competed for the binding sites. The order of potency was (-) isoproterenol greater than (-) epinephrine greater than (-)-norepinephrine which agreed with the order of potency of these agents in stimulating leukocyte adenylate cyclase. Dissociation constants computed from binding experiments were virtually identical to those obtained from adenylate cyclase activation studies. Marked stereospecificity was observed for both binding and activation of adenylate cyclase. (-)Stereoisomers of beta-adrenergic agonists and antagonists were 9- to 300-fold more potent than their corresponding (+) stereoisomers. Structurally related compounds devoid of beta-adrenergic activity such as dopamine, dihydroxymandelic acid, normetanephrine, pyrocatechol, and phentolamine did not effectively compete for the binding sites. (-) [3H] alprenolol binding to human mononuclear leukocyte preparations was almost entirely accounted for by binding to small lymphocytes, the predominant cell type in the preparations. No binding was detectable to human erythrocytes. These results demonstrate the feasibility of using direct binding methods to study beta-adrenergic receptors in a human tissue. They also provide an experimental approach to the study of states of altered sensitivity to catecholamines at the receptor level in man.

Modeling non-harmonic behavior of materials from experimental inelastic neutron scattering and thermal expansion measurements

Based on thermodynamic principles, we derive expressions quantifying the non-harmonic vibrational behavior of materials, which are rigorous yet easily evaluated from experimentally available data for the thermal expansion coefficient and the phonon density of states. These experimentally- derived quantities are valuable to benchmark first-principles theoretical predictions of harmonic and non-harmonic thermal behaviors using perturbation theory, ab initio molecular-dynamics, or Monte-Carlo simulations. We illustrate this analysis by computing the harmonic, dilational, and anharmonic contributions to the entropy, internal energy, and free energy of elemental aluminum and the ordered compound FeSi over a wide range of temperature. Results agree well with previous data in the literature and provide an efficient approach to estimate anharmonic effects in materials.

Beyond the Convent Walls: The Local and Japan-wide Activities of Daihongan’s Nuns in the Early Modern Period (c. 1550–1868)

This dissertation examines the social and financial activities of Buddhist nuns to demonstrate how and why they deployed Buddhist doctrines, rituals, legends, and material culture to interact with society outside the convent. By examining the activities of the nuns of the Daihongan convent (one of the two administrative heads of the popular pilgrimage temple, Zenkōji) in Japan’s early modern period (roughly 1550 to 1868) as documented in the convent’s rich archival sources, I shed further light on the oft-overlooked political and financial activities of nuns, illustrate how Buddhist institutions interacted with the laity, provide further nuance to the discussion of how Buddhist women navigated patriarchal sectarian and secular hierarchies, and, within the field of Japanese history, give voice to women who were active outside of the household unit around which early modern Japanese society was organized.

Zenkōji temple, surrounded by the mountains of Nagano, has been one of Japan’s most popular pilgrimage sites since the medieval period. The abbesses of Daihongan, one Zenkōji’s main sub-temples, traveled widely to maintain connections with elite and common laypeople, participated in frequent country-wide displays of Zenkōji’s icon, and oversaw the creation of branch temples in Edo (now Tokyo), Osaka, Echigo (now Niigata), and Shinano (now Nagano). The abbesses of Daihongan were one of only a few women to hold the imperially sanctioned title of eminent person (shōnin 上人) and to wear purple robes. While this means that this Pure Land convent was in some ways not representative of all convents in early modern Japan, Daihongan’s position is particularly instructive because the existence of nuns and monks in a single temple complex allows us to see in detail how monastics of both genders interacted in close quarters.

This work draws heavily from the convent’s archival materials, which I used as a guide in framing my dissertation chapters. In the Introduction I discuss previous works on women in Buddhism. In Chapter 1, I briefly discuss the convent’s history and its place within the Zenkōji temple complex. In Chapter 2, I examine the convent’s regular economic bases and its expenditures. In Chapter 3, I highlight Daihongan’s branch temples and discuss the ways that they acted as nodes in a network connecting people in various areas to Daihongan and Zenkōji, thus demonstrating how a rural religious center extended its sphere of influence in urban settings. In Chapter 4, I discuss the nuns’ travels throughout the country to generate new and maintain old connections with the imperial court in Kyoto, confraternities in Osaka, influential women in the shogun’s castle, and commoners in Edo. In Chapter 5, I examine the convent’s reliance upon irregular means of income such as patronage, temple lotteries, loans, and displays of treasures, and how these were needed to balance irregular expenditures such as travel and the maintenance or reconstruction of temple buildings. Throughout the dissertation I describe Daihongan’s inner social structure comprised of abbesses, nuns, and administrators, and its local emplacement within Zenkōji and Zenkōji’s temple lands.

Exploring these themes sheds light on the lives of Japanese Buddhist nuns in this period. While the tensions between freedom and agency on the one hand and obligations to patrons, subordination to monks, or gender- and status-based restrictions on the other are important, and I discuss them in my work, my primary focus is on the nuns’ activities and lives. Doing so demonstrates that nuns were central figures in ever-changing economic and social networks as they made and maintained connections with the outside world through Buddhist practices and through precedents set centuries before. This research contributes to our understanding of nuns in Japan’s early modern period and will participate in and shape debates on the roles of women in patriarchal religious hierarchies.

Weak coupling of acoustic-like phonons and magnon dynamics in incommensurate spin ladder compound Sr14Cu24O41

Intriguing lattice dynamics has been predicted for aperiodic crystals that contain incommensurate substructures. Here we report inelastic neutron scattering measurements of phonon and magnon dispersions in Sr14Cu24O41, which contains incommensurate one-dimensional (1D) chain and two-dimensional (2D) ladder substructures. Two distinct acoustic phonon-like modes, corresponding to the sliding motion of one sublattice against the other, are observed for atomic motions polarized along the incommensurate axis. In the long wavelength limit, it is found that the sliding mode shows a remarkably small energy gap of 1.7-1.9 meV, indicating very weak interactions between the two incommensurate sublattices. The measurements also reveal a gapped and steep linear magnon dispersion of the ladder sublattice. The high group velocity of this magnon branch and weak coupling with acoustic phonons can explain the large magnon thermal conductivity in Sr14Cu24O41 crystals. In addition, the magnon specific heat is determined from the measured total specific heat and phonon density of states, and exhibits a Schottky anomaly due to gapped magnon modes of the spin chains. These findings offer new insights into the phonon and magnon dynamics and thermal transport properties of incommensurate magnetic crystals that contain low-dimensional substructures.