Interview with Lib Guerry

In her October 11, 2012 interview with Robert Ryals, Lib Guerry recalls her two-year experience at Winthrop. This interview was conducted for inclusion into the Louise Pettus Archives and Special Collections Oral History Program.https://digitalcommons.winthrop.edu/oralhistoryprogram/1112/thumbnail.jp

Dr. William Coffee Daniell

William Coffee Daniell was born in Greene County, Georgia in 1792 and died in Liberty County, Georgia in 1868. He was Mayor of Savannah from 1824 to 1826 and was a professional physician and planter as well as politician. He was the author of a text on medicine, an antebellum call for southern political and economic unity and numerous letters.https://digitalcommons.georgiasouthern.edu/sav-bios-lane/1048/thumbnail.jp

State Reunion Maintainability for Semi-Markov Models

In previous research the importance of both Markov and semi-Markov models in manpower planning is highlighted. Maintainability of population structures for different types of personnel strategies (i.e. under control by promotion and control by recruitment) were extensively investigated for various types of Markov models (homogeneous as well as non-homogeneous). Semi-Markov models are extensions of Markov models that account for duration of stay in the states. Less attention is paid to the study of maintainability for semi-Markov models. Although, some interesting maintainability results were obtained for non-homogeneous semi-Markov models. The current paper focuses on discrete-time homogeneous semi-Markov models, and explores the concept of maintainable population structures in this setting. In particular, a new concept of maintainability is introduced, the so-called State Reunion maintainability. It is shown that this concept of maintainability is closely related to maintainability for non-homogeneous Markov chains

Nutrient constraints on plant community production and organic matter accumulation of subtropical floating marshes

In the cycle of delta growth and decay, peat-forming wetlands span a time and space continuum. Later in the delta cycle, freshwater floating marshes become increasingly removed from external sediment subsidy and internal nutrient cycling controls plant productivity and organic matter accumulation. An interesting question is whether increased external nutrient loading can affect the basic processes that lead to peat formation—plant production and organic matter decomposition. I conducted several field studies to understand whether belowground organic matter accumulation and decomposition were affected with increased nutrient exposure; in addition, the plant community was monitored over three years. A laboratory soil respiration experiment was run to determine potential limiting nutrients to microbial activity. After two years, there was a reduction of total belowground organic matter accumulation with increased nutrients; this partially resulted from reduced belowground root deposition coupled with accelerated root decomposition. This reduction in belowground accumulation, however, may be related also to the disappearance of a common plant of the community following fertilization, and not necessarily from a phenotypic shift in the allocation pattern by the dominant plant species. Fertilization accounted for an approximate doubling in aboveground biomass, accompanied by decreased stem density, and decreased species richness. Compared to other species, the grass, maidencane (Panicum hemitomon) responded most positively to increased nutrient availability at both sites, while at one site goldenrod (Solidago sempervirens) eventually captured a significant proportion of biomass. Nutrient resorption efficiency of nitrogen (N) and phosphorus (P) were both decreased with increased fertility. The degree of N- or P-limitation observed across coastal populations of P. hemitomon reflect the composite influences of site geology, water source, fire frequency, and the more conservative cycling of P compared to N. Plant community nutrient limitation may not be a reliable predictor of the type of nutrient limitation to soil microbes. Floating marshes have developed and are sustained under nutrient restricted conditions compared to other coastal marshes. Although floating marshes may function as nutrient sinks, a change in community and plant allocation pattern can be predicted with increased nutrient enrichment of these wetland types

The structure of phosphate glass biomaterials from neutron diffraction and 31P nuclear magnetic resonance data

Neutron diffraction and 31P nuclear magnetic resonance spectroscopy were used to probe the structure of phosphate glass biomaterials of general composition (CaO)0.5?x(Na2O)x(P2O5)0.5 (x = 0, 0.1 and 0.5). The results suggest that all three glasses have structures based on chains of Q2 phosphate groups. Clear structural differences are observed between the glasses containing Na2O and CaO. The P–O bonds to bridging and non-bridging oxygens are less well resolved in the neutron data from the samples containing CaO, suggesting a change in the nature of the bonding as the field strength of the cation increases Na+ ? Ca2+. In the (CaO)0.5(P2O5)0.5 glass most of the Ca2+ ions are present in isolated CaOx polyhedra whereas in the (Na2O)0.5(P2O5)0.5 glass the NaOx polyhedra share edges leading to a Na–Na correlation. The results of the structural study are related to the properties of the (CaO)0.4(Na2O)0.1(P2O5)0.5 biomaterial