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Bodden Town, Cayman Islands

St. Matthew's University is a for-profit university located in Grand Cayman, Cayman Islands in the Caribbean Wikipedia.

Taylor S.M.,Florida Institute of Technology | Taylor S.M.,St. Matthews University | Loew E.R.,Cornell University | Grace M.S.,Florida Institute of Technology
Visual Neuroscience

The Atlantic tarpon, Megalops atlanticus, is a large piscivorous fish that supports economically important recreational fisheries in the Gulf of Mexico, Caribbean, and Florida Atlantic coast. Megalops atlanticus undergoes ontogenetic shifts in morphology, hatching in the open ocean as larvae (less than 1 cm in length), moving into hypoxic turbid mangrove marshes as juveniles (around 10 cm in length), and then moving into coastal oceanic waters as adults (over 100 cm in length). In this study, photoreceptor distributions, opsin distributions, and photoreceptor absorbance characteristics were studied with light microscopy, transmission electron microscopy, antiopsin immunofluorescence, and microspectrophotometry, respectively, at four ecologically distinct life-history stages-premetamorphic larva, settlement stage, juvenile, and adult. The purposes of this study were 1) to determine the extent to which the retina of M. atlanticus changes over the course of development and 2) to relate these retinal changes with ecological shifts between developmental stages. The new data presented here indicate that the M. atlanticus retina changes substantially in rod and cone distributions and absorbance characteristics over the course of development and that these changes correlate closely with those in habitat and behavior. We show that M. atlanticus has a rod-dominated retina at the larval stage (which is unusual for teleost larvae) and that the scotopic visual system becomes far better developed with maturity, adding a substantial tapetum and high densities of small, bundled, and stacked rod cells. We also show that there are shifts in cone and rod spectral sensitivities and an increase in the diversity of spectrally distinct cone classes, including the addition of ultraviolet cones as fish mature into adults. © Cambridge University Press 2011. Source

Robson B.,St. Matthews University | Robson B.,University of Wisconsin - Stout | Robson B.,Quantal Inc.
Computers in Biology and Medicine

We recently introduced the concept of a Hyperbolic Dirac Net (HDN) for medical inference on the grounds that, while the traditional Bayes Net (BN) is popular in medicine, it is not suited to that domain: there are many interdependencies such that any "node" can be ultimately conditional upon itself. A traditional BN is a directed acyclic graph by definition, while the HDN is a bidirectional general graph closer to a diffuse "field" of influence. Cycles require bidirectionality; the HDN uses a particular type of imaginary number from Dirac's quantum mechanics to encode it. Comparison with the BN is made alongside a set of recipes for converting a given BN to an HDN, also adding cycles that do not usually require reiterative methods. This conversion is called the P-method. Conversion to cycles can sometimes be difficult, but more troubling was that the original BN had probabilities needing adjustment to satisfy realism alongside the important property called "coherence". The more general and simpler K-method, not dependent on the BN, is usually (but not necessarily) derived by data mining, and is therefore also introduced. As discussed, BN developments may converge to an HDN-like concept, so it is reasonable to consider the HDN as a BN extension. © 2014 Elsevier Ltd. Source

Simorangkir D.R.,University of Pittsburgh | Simorangkir D.R.,St. Matthews University | Ramaswamy S.,University of Pittsburgh | Marshall G.R.,Chatham University | And 2 more authors.

In primates, the time course of Sertoli cell proliferation and differentiation during puberty and its relationship with the expansion of undifferentiated type A spermatogonia that occurs at this critical stage of development are poorly defined. Mid and late juvenile and early and late pubertal male rhesus monkeys were studied. Testes were immersion fixed, embedded in paraffin, and sectioned at 5 μm. Sertoli cell number per testis, S-phase labeling (BrdU), and growth fraction (Ki67 labeling) were determined and correlated with corresponding parameters for undifferentiated type A spermatogonia (A dark and A pale). Dual fluorescence labeling was used in addition to histochemistry to monitor spermatogonial differentiation during the peripubertal period using GFRα-1 and cKIT as markers. While the adult complement of Sertoli cells/testis was attained in early pubertal monkeys after only a few weeks of exposure to the elevated gonadotropin secretion characteristic of this developmental stage, the number of undifferentiated type A spermatogonia several months later in mid pubertal monkeys was only 50% of that in adult testes. Both A dark and A pale spermatogonia exhibited high S-phase BrdU labeling at all stages of juvenile and pubertal development. Spermatogonial differentiation, as reflected histochemically and by relative changes in GFRα-1 and cKIT expression, was not observed until after the initiation of puberty. In the rhesus monkey and maybe in other higher primates including human, the pubertal proliferation of undifferentiated spermatogonia is insidious and proceeds in the wake of a surge in Sertoli cell proliferation following termination of the juvenile stage of development. © 2012 Society for Reproduction and Fertility. Source

Robson B.,St. Matthews University | Robson B.,University of Wisconsin - Stout
Computers in Biology and Medicine

Our previous reports described the use of the Hyperbolic Dirac Net (HDN) as a method for probabilistic inference from medical data, and a proposed probabilistic medical Semantic Web (SW) language Q-UEL to provide that data. Rather like a traditional Bayes Net, that HDN provided estimates of joint and conditional probabilities, and was static, with no need for evolution due to "reasoning". Use of the SW will require, however, (a) at least the semantic triple with more elaborate relations than conditional ones, as seen in use of most verbs and prepositions, and (b) rules for logical, grammatical, and definitional manipulation that can generate changes in the inference net. Here is described the simple POPPER language for medical inference. It can be automatically written by Q-UEL, or by hand. Based on studies with our medical students, it is believed that a tool like this may help in medical education and that a physician unfamiliar with SW science can understand it. It is here used to explore the considerable challenges of assigning probabilities, and not least what the meaning and utility of inference net evolution would be for a physician. © 2014 Elsevier Ltd. Source

Robson B.,St. Matthews University | Robson B.,University of Wisconsin - Stout | Li J.,Astrazeneca | Peters A.,Harvard University | Boyer S.K.,Collabra Inc.
Journal of Computer-Aided Molecular Design

A patent data base of 6.7 million compounds generated by a very high performance computer (Blue Gene) requires new techniques for exploitation when extensive use of chemical similarity is involved. Such exploitation includes the taxonomic classification of chemical themes, and data mining to assess mutual information between themes and companies. Importantly, we also launch candidates that evolve by "natural selection" as failure of partial match against the patent data base and their ability to bind to the protein target appropriately, by simulation on Blue Gene. An unusual feature of our method is that algorithms and workflows rely on dynamic interaction between match-andedit instructions, which in practice are regular expressions. Similarity testing by these uses SMILES strings and, less frequently, graph or connectivity representations. Examining how this performs in high throughput, we note that chemical similarity and novelty are human concepts that largely have meaning by utility in specific contexts. For some purposes, mutual information involving chemical themes might be a better concept. © 2011 Springer Science+Business Media B.V. Source

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