Southern Illinois University Carbondale

About: Southern Illinois University Carbondale is a education organization based out in Carbondale, Illinois, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 13570 authors who have published 24819 publications receiving 667385 citations. The organization is also known as: SIU Carbondale & SIUC.

Symmetry Relationship and Strain-Induced Transitions between Insulating M1 and M2 and Metallic R phases of Vanadium Dioxide

Abstract: The ability to synthesize VO{sub 2} in the form of single-crystalline nanobeams and nano- and microcrystals uncovered a number of previously unknown aspects of the metal-insulator transition (MIT) in this oxide. In particular, several reports demonstrated that the MIT can proceed through competition between two monoclinic (insulating) phases M1 and M2 and the tetragonal (metallic) R phase under influence of strain. The nature of such phase behavior has been not identified. Here we show that the competition between M1 and M2 phases is purely lattice-symmetry-driven. Within the framework of the Ginzburg-Landau formalism, both M phases correspond to different directions of the same four-component structural order parameter, and as a consequence, the M2 phase can appear under a small perturbation of the M1 structure such as doping or stress. We analyze the strain-controlled phase diagram of VO{sub 2} in the vicinity of the R-M2-M1 triple point using the Ginzburg-Landau formalism and identify and experimentally verify the pathways for strain-control of the transition. These insights open the door toward more systematic approaches to synthesis of VO{sub 2} nanostructures in desired phase states and to use of external fields in the control of the VO{sub 2} phase states. Additionally, we report observation ofmore » the triclinic T phase at the heterophase domain boundaries in strained quasi-two-dimensional VO{sub 2} nanoplatelets, and theoretically predict phases that have not been previously observed.« less

Single-Locus Latitudinal Clines and Their Relationship to Temperate Adaptation in Metabolic Genes and Derived Alleles in Drosophila melanogaster

Abstract: We report a study in Drosophila melanogaster of latitudinal clines for 23 SNPs embedded in 13 genes (Pgi, Gapdh1, UGPase, Pglym78, Pglym87, Eno, Men, Gdh, Sod, Pgk, Mdh1, TreS, Treh) representing various metabolic enzymes. Our samples are from 10 populations spanning latitude from southern Florida to northern Vermont. Three new clines with latitude were detected. These are the amino acid polymorphisms in the NAD-dependent glutamate dehydrogenase (Gdh) and trehalase (Treh) genes, and a silent site polymorphism in the UDP-glucose pyrophosphorylase gene (UGPase). The result, when combined with the overall incidence and pattern of reports for six other genes (Adh, Gpdh, Pgm, G6pd, 6Pgd, Hex-C), presents a picture of latitudinal clines in metabolic genes prevalent around the branch point of competing pathways. For six of the seven amino acid polymorphisms showing significant latitudinal clines in North America, the derived allele is the one increasing with latitude, suggesting temperate adaptation. This is consistent with a model of an Afrotropical ancestral species adapting to temperate climates through selection favoring new mutations.

Horizontal transfer of an adaptive chimeric photoreceptor from bryophytes to ferns

Abstract: Ferns are well known for their shade-dwelling habits. Their ability to thrive under low-light conditions has been linked to the evolution of a novel chimeric photoreceptor—neochrome—that fuses red-sensing phytochrome and blue-sensing phototropin modules into a single gene, thereby optimizing phototropic responses. Despite being implicated in facilitating the diversification of modern ferns, the origin of neochrome has remained a mystery. We present evidence for neochrome in hornworts (a bryophyte lineage) and demonstrate that ferns acquired neochrome from hornworts via horizontal gene transfer (HGT). Fern neochromes are nested within hornwort neochromes in our large-scale phylogenetic reconstructions of phototropin and phytochrome gene families. Divergence date estimates further support the HGT hypothesis, with fern and hornwort neochromes diverging 179 Mya, long after the split between the two plant lineages (at least 400 Mya). By analyzing the draft genome of the hornwort Anthoceros punctatus, we also discovered a previously unidentified phototropin gene that likely represents the ancestral lineage of the neochrome phototropin module. Thus, a neochrome originating in hornworts was transferred horizontally to ferns, where it may have played a significant role in the diversification of modern ferns.

Short term financial success in large business organizations: The environment-strategy connection

Abstract: This study examines the interrelationships of environmental changes and strategic action variables with each other and with short term success, for 358 large business firms over a 45 year period. Success (Fortune ratings and ROA) is found to be related to two strategic decision segments. Several strategy-environment relationships are also found. Some methodological problems are noted in the attempt to move policy research from case analysis to statistical explanation.

Testing a Model of Cognitive Budgetary Participation Processes in a Latent Variable Structural Equations Framework

Abstract: Previous accounting research has suggested that subordinate participation in the budgetary process has two cognitive aspects: (1) participation enhances budget quality, and hence the utility of budgets, by allowing subordinates to introduce private knowledge into the budgetary process, and (2) participation enables subordinates to obtain information that is relevant to performing their jobs. This study tests a model that encompasses both cognitive aspects of budgetary participation. Data were gathered with a questionnaire distributed to managers from a variety of different national origins who were working in many different global locations. The data were analysed with latent variable structural equation modelling, which provides several advantages over more conventional analytic methods generally used in budgetary participation and other behavioural accounting research. The results indicated that participation enhances budget quality and that budget quality, in turn, has a positive effect on bud...