Faculty Research and Publications

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    Addendum - Four more Trinidadian Spider (Araneida) families
    (Living World, J. Trinidad and Tobago Field Naturalists’ Club, 2007) Sewlal, Jo-Anne N; Alayón, Giraldo
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    Annotated List of Spider Families (Araneida) of Trinidad and Tobago
    (Living World, J. Trinidad and Tobago Field Naturalists’ Club, 2003) Sewlal, Jo-Anne N; Cutler, Bruce
    The spider families of the neotropical islands of Trinidad and Tobago are reviewed. Forty one families are definitely recorded, while an additional 12 families are considered as likely, based on their presence in the nearby South American mainland. Biological and recognition characters are noted for most of the families.
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    Books Published and Papers presented
    (2011-02-08) Kalicharan, Noel
    15 books about computer programming and 10 papers about the issues related to information technology
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    Checklist of Orb-Weaving Spiders of Trinidad and Tobago Belonging to the Families Araneidae, Nephilidae and Tetragnathidae.
    (Living World, J. Trinidad and Tobago Field Naturalists’ Club, 2010) Sewlal, Jo-Anne N
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    Comparative Nesting Habits and Colony Composition of Three Arboreal Termites (Isoptera: Termitidae) in Trinidad and Tobago, West Indies
    (2010) Merritt, Neasha R.C; Starr, Christopher
    In a survey of arboreal termites in different habitats in Trinidad and Tobago, West Indies, three species predominated: Microcerotermes arboreus, Nasutitermes corniger and N. ephratae. M. arboreus accounted for most colonies in a pine plantation, while N. corniger predominated in farmland and mangrove. The two species had roughly equal proportions, overall, at several broadleafforest sites. A fourth species, either Termes hispaniolae or T. fatalis, appeared only in broadleaf forest. Each of the three common species shows wide variance in nest height within habitats. The overall pattern is consistent with much greater withinspecies variation among habitats than among species in the same habitat. In no habitat is there a clear height differentiation among species. Analysis of colonies shows the expected similarity in the two species of nasute-termites. Both showed a mean soldier fraction of 17% among adults, while in M. arboreus only 3% of adults were soldiers. Features of nest structure may be related to this difference
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    COMPARING A NOVEL QOS ROUTING ALGORITHM TO STANDARD
    (2010-11-19T16:42:41Z) Sivakumar, Shyamala; Phillips, Bill; Robertson, William; Goodridge S., Wayne
    The problem of finding QoS paths involving several combinations of network metrics is NP-complete. This motivates the use of heuristic approaches for finding feasible QoS paths. Many constraint based routing algorithms find QoSpaths by first pruning resources that do not satish the requirements of the trafic flow and then running a shortest path algorithm on the residual graph. This approach results in a QoS path that biases thefirst metric used in the search process. In addition, it can be shown that this approach may not alwaysfind the optimal path. Our research introduces a QoS routing algorithm that is based on a decision support system that is used to compute QoS paths. We demonstrate the feasibility of this approach by comparing it to standard pruning techniques.
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    The Distribution of the Frog Eleutherodactylus johnstonei (Amphibia:Eleutherodactylidae) in Trinidad, West Indies
    (2012-02-14) Manickchan, Shiva A.; Starr, Christopher K.; Ramjohn, Carol; Mahabir, Srishti V.; Mahabir, Kevin; Mohammed, Ryan S.
    Eleutherodactylus johnstonei is an invasive anuran of Trinidad, West Indies. Monitoring the spread has shown that its local range is the north-west of Trinidad. E. johnstonei is increasing in population size and is increasing its local range by expanding into disturbed habitats. No immediate ecological threat has been identified. Previous studies on high amplitude callers suggest that E. johnstonei has the potential to become a pest in urban residential areas due to its loud mating calls. It is likely that E. johnstonei has become a permanent part of Trinidad’s biodiversity and its calls would become common in many more suitable disturbed areas in Trinidad.
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    Getting to know our sea turtles
    (Tobago News, 2009-07-10) Sewlal, Jo-Anne
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    Heuristic Constraint-Path Routing Decision System
    (IEEE Computer Society, 2005-05-18) Sivakumar, Shyamala; Phillips, William J.; Robertson, William; Goodridge, Wayne
    Heuristic QoS algorithms under strict constraints perform poorly in terms of finding a path that is suitable for a user?s QoS needs - the multiple constraint path problem (MCP). Exact QoS algorithms, on the other hand, guarantee that a path satisfying user needs would be found and o..er a more realistic approach for solving the MCP problem in view of the fact that the NP-complete character of graphs are not common in real networks. This fact has driven approaches like the SAMCRA and A*prune algorithms. However, these algorithms still have very high running times relative to heuristic approaches. When QoS routing algorithms are used in online Tra..c Engineering (TE) environments it may be necessary to route thousands of traffic flows each minute. Exact algorithms simply cannot work in such environments. We propose a heuristic algorithm that is suitable for working in an online TE environment. Simulations show that this algorithm produce high success rates in terms of finding suitable constraint paths for user flows while at the same time having execution times comparable to another heuristic based algorithms.
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    How Water can Help and Hurt Biodiversity
    (Tobago News, 2010-07-17) Sewlal, Jo-Anne
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    Integrating Two Artificial Intelligence Theories in a Medical Diagnosis Application
    (2010-11-03T14:27:45Z) Peter, Hadrain; Goodridge, Wayne
    Reasoning Systems (Inference Mechanisms) and Neural Networks are two major areas of Artificial Intelligence(AI). The use of case-based reasoning in Artificial Intelligence systems is well known. Similarly, the AI literature is replete with papers on neural networks. However, there is relatively little research in which the theories of case-based reasoning and neural networks are combined.In this paper we integrate the two theories and show how the resulting model is used in a medical diagnosis application.An implementation of our model provides a valuable prototype for medical experts and medical students alike.
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    Karyotype and male reproductive system in Arachnocoris trinitatus Bergroth. First data on the tribe Arachnocorini (Heteroptera: Nabidae: Nabinae). Folia Biologica (Kraków)
    (Folia biologica (Kraków), 2007) Kuznetsova, Valentina G.; Grozeva, Snejana; Sewlal, Jo-Anne N; Nokkala, Seppo
    As an extension of the ongoing cytogenetic studies of the bug family Nabidae (Heteroptera:Cimicomorpha), the first evidence for the tribe Arachnocorini (the subfamily Nabinae), with reference to the Trinidad endemic, Arachnocoris trinitatus Bergroth, is provided. This is an attempt to gain a better insight into the evolution, systematics and within-family relationships of the family Nabidae. The studies were conducted using a number of cytogenetic techniques. The male karyotype (chromosome number and size; sex chromosome system; NOR location; C-heterochromatin amount, distribution and characterization in terms of the presence of AT-rich and GC-rich DNA), and male meiosis with particular emphasis on the behavior of the sex chromosomes in metaphase II are described. Also investigated are the male and female internal reproductive organs with special reference to the number of follicles in a testis and the number of ovarioles in an ovary. A. trinitatus was found to display a number of characters differentiating it from all hitherto studied nabid species placed in the tribe Nabini of the subfamily Nabinae, and in the tribe Prostemmatini of the subfamily Prostemmatinae. Among these characters are chromosome number 2n = 12 (10 + XY), the lowest within the family, nucleolus organizer regions (NORs)situated on the autosomes rather than on the sex chromosomes as is the case in other nabid species, and testes composed of 3 follicles but not of 7 as in other nabids. All the data obtained suggest many transformations during the evolution of A. trinitatus.
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    Life between leaves on the Forest Floor
    (Tobago News, 2010-07-09) Sewlal, Jo-Anne
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    Macroecology - getting the big picture
    (Tobago News, 2012-12-12) Sewlal, Jo-Anne
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    The Neotropical social wasp Mischocyttarus ‘alfkenii’ Ducke (Hymenoptera: Vespidae) is a pair of ethospecies
    (2012-06-28) O'Connor, Timothy K.; Starr, Christopher.K; Cameron, Sydney A.
    In Trinidad, West Indies, wasps matching the description of Mischocyttarus alfkenii build two readily distinguishable nest forms, differing both in architecture (excentric versus centric petiole) and colour (yellowish grey-brown versus reddish medium brown). Analysis of two mitochondrial genes (16S and cytochrome c oxidase subunit I, COI) in excentric- and centric-form M. ‘alfkenii’ consistently segregates individuals from the two nest forms, with genetic divergences comparable with those observed among other species in the genus. Geometric morphometric analysis of wing venation likewise recovers consistent differences between nest forms. Integrating behavioural, genetic and morphometric evidence corroborates the hypothesis that the two nest forms correspond to distinct species of recent common ancestry. Notes accompanying the description of M. alfkenii indicate that the name belongs to the species in which the nest has an excentric petiole and paler carton. The other species is described as Mischocyttarus baconi
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    Nest reutilization by Polistes Metricus (Hymenoptera: Vespidae) and possible limitation of multiple foundress associations by parasitoids
    (2016-03-10) Starr, C.K.
    The reutilization is reported of an old nest by three female wasps, and the condition of the nest and its constituent cells, is recorded at the end of the season. Larvae of the pyralid genus Chalcoela are believed to have been a major cause of the nest's apparent low productivity. It is postulated that strong parasitoid pressure by Chalcoela is a selective factor against nest-founding by associated multiple queens in some North American species of Polistes.
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    Nest Reutilization by Polistes metricus (Hymenoptera: Vespidae) and Possible Limitations of Multiple Foundress Associations by Parasitoids
    (1976-01) Starr, C. K.
    The reutilization is reported of an old nest by three female wasps, and the condition of the nest and its constituent cells, is recorded at the end of the season. Larvae of pyralid genus Chalcoela are believed to have been a major cause of the nest's apparent low productivity. It is postulated that strong parasitoid pressure by Chalcoela is a selective factor against nest-founding by associated multiple queens in some North American species of Polistes.
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    New Record of Pholcid genera for Lesser Antilles, West Indies.
    (Living World, J. Trinidad and Tobago Field Naturalists’ Club, 2008) Sewlal, Jo-Anne N; Starr, Christopher K
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    An observation of nest relocation in the ant Cephalotes atratus
    (Living World, J. Trinidad and Tobago Field Naturalists’ Club, 2004) Starr, Christopher K; Sewlal, Jo-Anne N