Simple model for the phase coexistence and electrical conductivity of alkali fluids

We report the first theoretical model for the alkali fluids which yields a liquid-vapor phase coexistence with the experimentally observed features and electrical conductivity estimates which are also in accord with observations. We have carried out a Monte Carlo simulation for a lattice gas model which allows an integrated study of the structural, thermodynamic, and electronic properties of metal-atom fluids. Although such a technique is applicable to both metallic and nonmetallic fluids, non-additive interactions due to valence electron delocalization are a crucial feature of the present model.Comment: RevTex, 11 pages, 2 ps figure files appended, submitted to PR

Study of theoretical models for the liquid-vapor and metal-nonmetal transitions of alkali fluids

Theoretical models for the liquid-vapor and metal-nonmetal transitions of alkali fluids are investigated. Mean-field models are considered first but shown to be inadequate. An alternate approach is then studied in which each statistical configuration of the material is treated as inhomogeneous, with the energy of each ion being determined by its local environment. Nonadditive interactions, due to valence electron delocalization, are a crucial feature of the model. This alternate approach is implemented within a lattice-gas approximation which takes into account the observed mode of expansion in the materials of interest and which is able to treat the equilibrium density fluctuations. We have carried out grand canonical Monte Carlo simulations, for this model, which allow a unified, self-consistent, study of the structural, thermodynamic, and electronic properties of alkali fluids. Applications to Cs, Rb, K, and Na yield results in good agreement with observations.Comment: 13 pages, REVTEX, 10 ps figures available by e-mail

A PUBLIC DUTY: MEDICINE AND COMMERCE IN NINETEENTH-CENTURY AMERICAN LITERATURE AND CULTURE

Using recent criticism on speculation and disability in addition to archival materials, “A Public Duty: Medicine and Commerce in Nineteenth-Century American Literature and Culture” demonstrates that reform-minded nineteenth-century authors drew upon the representational power of public health to express excitement and anxiety about the United States’ emerging economic and political prominence. Breaking with a critical tradition holding that the professionalization of medicine and authorship served primarily to support and define an ascending middle class, I argue that the authors such as Robert Montgomery Bird, Fanny Fern, George Washington Cable, and Pauline Hopkins fuse the rhetoric of economic policy and public health to advocate that the era’s disenfranchised “ill” (classified as such due to demographic factors or disability/disease) be recognized as worthy citizens capable of enhancing the economic and cultural wealth of the nation. While many nineteenth-century authors drew upon the ability for sickness and death to unify disparate peoples, such instances often tend toward sentimentalism, imparting the message of inclusion by invoking readers’ sympathy. The authors included in my project, however, do not fit this mode. Instead, they used their works to insinuate that looking after the health and welfare of one’s fellow humans was simply good economics. In featuring issues of public health rather than private disability, depicting illness realistically in accordance with medical treatises and beliefs of the period, and showing the widespread consequences of disease these writers rely on their readers’ desire for economic prosperity, rather than affect, as a catalyst for social solidarity in a capitalist society. As such, my project causes us to rethink how the ascent of the novel not only helped define, but also challenged and critiqued, the identity-politics of an emerging middle class. By showing the authors studied in “A Public Duty” used literature’s pedagogical potential to argue the “sick” literally and figuratively had worth, I demonstrates these writers’ works help create and support a reconceptualization of the political body suiting a country poised to assume global prominence and urged their readers to see the variety of people living in the United States as a source of national innovation and strength

RNA-binding protein Elavl1/HuR is required for maintenance of cranial neural crest specification

Neural crest development is transcriptionally controlled via sequential activation of gene regulatory networks (GRNs). Recent evidence increasingly implicates a role for post-transcriptional regulation in modulating the output of these regulatory circuits. Using RNA-sequencing data from avian embryos to identify potential post-transcriptional regulators, we observed enrichment during early neural crest development of Elavl1, which encodes for the RNA-binding protein HuR. Immunohistochemical analyses revealed expression of HuR following establishment of the neural plate border. Perturbation of HuR resulted in premature neural crest delamination from the neural tube as well as significant reduction in transcripts associated with the neural crest specification GRN (Axud1 and FoxD3), phenotypes also observed with downregulation of the canonical Wnt inhibitor Draxin. RNA pulldown further shows that Draxin is a specific target of HuR. Importantly, overexpression of exogenous Draxin was able to rescue the cranial neural crest specification defects observed with HuR knockdown. Thus, HuR plays a critical a role in the maintenance of cranial neural crest specification, at least partially via Draxin mRNA stabilization. Together, these data highlight an important intersection of post-transcriptional regulation with modulation of the neural crest specification GRN