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Daytona Beach, FL, United States

Bethune-Cookman University, or simply B-CC or B-CU, is a private historically black university in Daytona Beach, Florida, United States. White Hall has been added to the US National Register of Historic Places. Wikipedia.

Wollenberg Valero K.C.,Bethune-Cookman University
Frontiers in Genetics | Year: 2015

The endemic Malagasy frog radiations are an ideal model system to study patterns and processes of speciation in amphibians. Large-scale diversity patterns of these frogs, together with other endemic animal radiations, led to the postulation of new and the application of known hypotheses of species diversification causing diversity patterns in this biodiversity hotspot. Both extrinsic and intrinsic factors have been studied in a comparative framework, with extrinsic factors usually being related to the physical environment (landscape, climate, river catchments, mountain chains), and intrinsic factors being clade-specific traits or constraints (reproduction, ecology, morphology, physiology). Despite some general patterns emerging from such large-scale comparative analyses, it became clear that the mechanism of diversification in Madagascar may vary among clades, and may be a multifactorial process. In this contribution, I test for intrinsic factors promoting population-level divergence within a clade of terrestrial, diurnal leaf-litter frogs (genus Gephyromantis) that has previously been shown to diversify according to extrinsic factors. Landscape genetic analyses of the microendemic species Gephyromantis enki and its widely distributed, larger sister species Gephyromantis boulengeri over a rugged landscape in the Ranomafana area shows that genetic variance of the smaller species cannot be explained by landscape resistance alone. Both topographic and riverine barriers are found to be important in generating this divergence. This case study yields additional evidence for the probable importance of body size in lineage diversification. © 2015 Wollenberg Valero.

Alabugin I.V.,Florida State University | Gilmore K.,Florida State University | Manoharan M.,Bethune-Cookman University
Journal of the American Chemical Society | Year: 2011

This work reexamined the stereoelectronic basis for the "favored attack trajectories" regarding the nucleophilic and radical cyclizations of alkynes. In contrast to the original Baldwin rules, the acute attack angle of a nucleophile leading to the proposed endo-dig preference for the formation of small cycles is less favorable stereoelectronically than the alternative obtuse trajectory leading to the formation of exo-dig products. For smaller cycles, this intrinsic stereoelectronic preference can be masked by the greater thermodynamic stability of the less strained endo-products. Unbiased comparison of competing cyclization attacks has been accomplished via dissection of the activation barrier into the intrinsic barrier and thermodynamic component via Marcus theory. Intrinsic barriers of thermoneutral reactions strongly favor exo-dig closures, in full accord with the greater magnitude of two-electron bond forming interactions for the obtuse trajectory. This analysis agrees very well with experimental observations of efficient 3-exo-dig and 4-exo-dig cyclizations predicted to be unfavorable by the Baldwin rules and with the calculated 3-exo-/4-endo-, 4-exo-/5-endo-, and 5-exo-/6-endo-dig selectivities in the cyclizations of carbon-, nitrogen-, and oxygen-centered nucleophiles. The generality of these predictions is confirmed by analogous trends for the related radical cyclizations where the stereoelectronically favorable exo-closures are also preferred kinetically, with a few exceptions where a large difference in product stability skews the intrinsic stereoelectronic trends. © 2011 American Chemical Society.

Gilmore K.,Florida State University | Manoharan M.,Bethune-Cookman University | Wu J.I.-C.,University of Georgia | Schleyer P.V.R.,University of Georgia | Alabugin I.V.,Florida State University
Journal of the American Chemical Society | Year: 2012

The transition states (TSs) of 5-endo-dig and 5-endo-trig anionic ring closures are the first unambiguous examples of nonpericyclic reactions with TSs stabilized by aromaticity. Their five-center, six-electron in-plane aromaticity is revealed by the diatropic dissected nucleus-independent chemical shifts, -24.1 and -13.7 ppm, respectively, resulting from the delocalization of the lone pair at the nucleophilic center, a σ CC bond, and an in-plane alkyne (or alkene) π bond. Other seemingly analogous exo and endo cyclization TSs do not have these features. A symmetry-enhanced combination of through-space and through-bond interactions explains the anomalous geometric, energetic, and electronic features of the 5-endo ring closure transition state. Anionic 5-endo cyclizations can be considered to be "aborted" [2,3]-sigmatropic shifts. The connection between anionic cyclizations and sigmatropic shifts offers new possibilities for the design and electronic control of anionic isomerizations. © 2012 American Chemical Society.

Alabugin I.V.,Florida State University | Bresch S.,Florida State University | Manoharan M.,Bethune-Cookman University
Journal of Physical Chemistry A | Year: 2014

Trends in hybridization were systematically analyzed through the combination of DFT calculations with NBO analysis for the five elements X (X = B, C, N, O, and F) in 75 HnX-YHm compounds, where Y spans the groups 13-17 of the periods 2-4. This set of substrates probes the flexibility of the hybridization at five atoms X through variations in electronegativity, polarizability, and orbital size of Y. The results illustrate the scope and limitations of the Bent's rule, the classic correlation between electronegativity and hybridization, commonly used in analyzing structural effects in carbon compounds. The rehybridization effects are larger for fluorine- and oxygen-bonds than they are in the similar bonds to carbon. For bonds with the larger elements Y of the lower periods, trends in orbital hybridization depend strongly on both electronegativity and orbital size. For charged species, the effects of substituent orbital size in the more polarizable bonds to heavier elements show a particularly strong response to the charge introduction at the central atom. In the final section, we provide an example of the interplay between hybridization effects with molecular structure and reactivity. In particular, the ability to change hybridization without changes in polarization provides an alternative way to control structure and reactivity, as illustrated by the strong correlation of strain in monosubstituted cyclopropanes with hybridization in the bond to the substituent. © 2014 American Chemical Society.

Powell E.N.,University of Southern Mississippi | Kim Y.,Bethune-Cookman University
Journal of Shellfish Research | Year: 2015

The Mussel Watch Program sampled bays on the East, Gulf, and West coasts of the United States over a period of 16 y. Analytical protocols included the recording of parasites and pathologies. Oysters (Crassostrea virginica) harbored significantly more parasitic taxa than mussels (Mytilidae). Cases where body burden was higher in mytilids were exclusively eukaryotic parasites, trematode metacercariae and trematode sporocysts. Oysters had higher body burdens of Nematopsis, alimentary tract ciliates, prokaryotic inclusions, and a number of unique taxa including haplosporidians, Perkinsus marinus, cestodes, and nematodes. Major pathologies were much more common in mytilids. For oysters, many parasitic taxa were more common in the Gulf of Mexico, including Nematopsis, P. marinus, trematode sporocysts, and nematodes. For mytilids, most parasites and pathologies were more common on the East Coast. Most parasite distributions were clinal on the East and West coasts, with clear relationships to well-known provincial boundaries. West Coast mytilids and East Coast oysters showed a similar trend toward increased parasite weighted prevalence in the south. The greater body burdens in Gulf Coast oysters might be a continuation of this trend. East Coast mytilids offer an opposing trend with higher body burdens in the Gulf of Maine. An increasing incidence of pathologies in mytilids at northern latitudes on both coasts runs contrary to the antithetical trends on the two coasts for parasite weighted prevalences. Within the parasite-rich Gulf of Mexico, oysters from the Texas coast were notable for their higher parasite body burdens. Some parasites and pathologies tended to have low variance-to-mean ratios and thus be identified as having even distributional patterns. Others showed a large range of weighted prevalences within a region and thus had contagious distributional patterns. With the exception of P. marinus, most of the contagious parasites were single celled. The multicellular taxa were more uniformly distributed: they tended to have much lower variance-to-mean ratios. Likely, the difference in spatial distribution between single-celled and multicellular taxa is due to the tendency for single-celled organisms to proliferate within the host or, being small, the ability to accumulate in larger numbers within the host.

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