Island Of Trinidad Research Articles

Hot bitumen burns: 92 hospitalized patients

Bitumen burns while comprising a small percentage of all types of burns are toublesome. They affect persons engaged in gainful employment which the burns then curtail, as well as requiring special attention because the substance adheres to the skin and is therefore difficult to remove. Ninety-two consecutive patients wich such burns who were admitted as in-patients over a 10-year period (1985–1995) have been reviewed. Most of the burns occurred on a worksite and involved active young persons (mean age 29.6 years) the mean size of the burn was 3.87 per cent TBSA, mainly affecting the upper extremities and hands. Mean hospitalization time was 10.6 days. Bitumen burns are fully predictable and can easily be prevented by avoiding unsafe practice and/or equipment. Bitumen is a general term for petroleum-derived substances ranging from true petroleum through so-called mineral tars, to asphalt. Asphalt (Asphaltum) is a semi-solid mixure of several hydrocarbons probably formed by the evaporation of the lighter or more volatile constituents. It is amorphous of low specific gravity, 1–2, with a black or brownish black colour and pitchy lustre. At room temperature it is solid becoming molten and spreadable when heated to 93°C and over. Roofing tars and asphalts are usually heated to temperatures of 232°C to achieve desirable viscosities (e.g. for spraying), whereas lower temperatures are required for the manageable form to pave roads 1,7. Notable localities for asphaltum are the island of Trinidad and the Dead Sea region where lake asphaltums were long known to the ancient. Ironically, none of the 92 patients who were treated for bitumen injuries in the ‘Soroka’ (Beer-Sheba, Israel) and ‘Barzilai’ (Ashkelon, Israel) Medical Centres (80 and 150 km from the lake respectively) had anything to do with the Dead Sea area.

Climate changes in the greater and southern Caribbean

A climate change resulting from recent increases in the atmospheric greenhouse gases (GHGs) is supposed to occur sometime in the middle of the next century. This climate change induced by GHGs would be caused by radiative forcing through the greenhouse effect and would lead to global warming and eventually to sea-level rise. This paper presents a climate change scenario for the greater Caribbean as simulated by the Canadian Climate Centre (CCC) general circulation model (GCM). The CCC GCM projects a GHG induced temperature increase of about 2°C and more extreme rainfall conditions for the greater Caribbean. The climate records of temperature, rainfall and cloudiness for several stations on the island of Trinidad are then examined in an attempt to detect GHG climate change signals. The temperature change to date, close to 1°C, and the fluctuations in rainfall patterns, over the last five decades, seem to be indicative of early greenhouse signals. © 1997 The Royal Meteorological Society.

Delayed development in the short-tailed fruit bat, Carollia perspicillata.

Pregnancy was studied in short-tailed fruit bats, Carollia perspicillata, both maintained in a captive breeding colony and collected from a reproductively synchronized wild population on the island of Trinidad. Gestation periods for captive females that successfully reared their young varied as follows: mated at a regular oestrus during their first year in captivity (105-178 days) (mean +/- SD: 145 +/- 19 days); mated at a postpartum oestrus during their first year in captivity (110-158 days) (133 +/- 16 days); mated during their second year in captivity (113-169 days) (127 +/- 12 days); females born and mated in captivity (113-159 days) (119 +/- 9 days). Most females in the last group had gestation periods of 113-119 days; this may represent the normal (nondelayed) gestation period for the species. Histological studies established that most of the observed variation in duration of gestation was due to delays occurring after the completion of implantation. It seems likely that stress, rather than age, was responsible for the prolongation of pregnancy in some animals, because this occurred less frequently in both younger and older females. There may be stressful situations in the wild (for example, lack of sufficient food or roosting sites) in which the ability to delay pregnancies would be of considerable adaptive value. Evidence was obtained that under some circumstances Carollia can extend gestation even further. Many wildcaught females successfully gave birth at 160-229 days after being isolated from breeding males in captivity. These had been captured at the time of year when, based upon subsequent histological studies of field collected specimens, most adult females should have been in early pregnancy. The field studies have also provided evidence that females in the wild population exhibit a seasonal prolongation of pregnancy.

Melatonin rhythms and pineal structure in a tropical bat, Anoura geoffroyi, that does not use photoperiod to regulate seasonal reproduction.

It has been hypothesized that pineal structure and function might differ between temperate zone and tropical species of mammals because of lower amplitudes of seasonal change in photoperiod and, in some areas, less seasonal climatic variation. Anoura geoffroyi produce a single offspring in November or December of each year on the Caribbean island of Trinidad, at 10 degrees N latitude in the deep tropics. Previous work has shown that this population lacks reproductive responses to photoperiod, and must be enforcing seasonal breeding using a non-photoperiodic cue. Anoura geoffroyi have a minute, thin, and rod-like pineal gland. Throughout much of its length, the pineal courses irregularly within the ventrolateral wall of the great cerebral vein. This intimate relationship may have functional implications. Despite having a very small pineal gland, this species produced a nocturnal rise in serum melatonin. Serum melatonin levels in most individuals were below or near undetectable levels during the light period and rose to a peak averaging 100 pg/ml in the last third of the dark period. Our results indicate that, although the pineal gland of A. geoffroyi is extremely small, serum melatonin levels are comparable to those of other mammals.

Increasing Oil Production Through Leasing of Idle Wells

The national oil company of Trinidad and Tobago (Petrotrin) has more than 5,000 idle wells. The company initiated a procedure for leasing these idle wells to small independent operators in July 1989 through a program known as the lease operatorship program. This paper reviews the status of lease operatorship activities, examines the benefits and the strategies adopted by the operators as well as some of the important issues involved, describes the requirements for external operatorship, and outlines planes for the future of the program.

The ‘Black Atlantic Communication Network’: African American Sailors and the Cape of Good Hope Connection

Francis Seymour, a curly headed nigger from the land of stars and stripes, was brought up for having shown a little too much of the Yankee spirit of independence... He became refractory, refused to do any [work], demanded a sovereign from Mr. Neethling, said....that if he did not get the sovereign he would knock it out of [him]. His abuse was very unsparing, and he was only prevented from “knocking it out” by the opportune appearance of Mr. J. J. Meintjes, who procured a police officer, and the “man of independent mind” was given into custody.While on its homeward passage in 1813, the whaling ship William Penn was intercepted off the island of Trinidad in the South Atlantic by a British frigate, boarded, and informed of the existence of war; and that the American seamen were prisoners of H.M.S. Acorn. Within a half hour, the Acorn and its prize (now manned by English sailors) were underway, heading off southeast for the Cape of Good Hope. After a passage of forty days they anchored in Table Bay.

History of Shiny Cowbird Molothrus bonariensis brood parasitism in Trinidad and Tobago

In attempting to evaluate the evolutionary stability of the reproductive strategies of an avian brood parasite, it is important to know whether or not the observed levels of parasitism on host species have changed through time and whether or not new host species are being used in the region under study. In this regard, the islands of Trinidad and Tobago provide an excellent opportunity because they are ornithologically well known and the expansion of the parasitic Shiny Cowbird Molothrus bonariensis into the West Indian region is thought to have originated from Trinidad and Tobago. On the whole, host choice has remained remarkably stable over the past 50–60 years. The three hosts (House Wren Troglodytes aedon, Red‐breasted Blackbird Leistes militaris and Yellow‐hooded Blackbird Agelaius icterocephalus) known to be heavily parasitized historically remain heavily parasitized today. Only one instance of parasitism of a new host (Tropical Kingbird Tyrannus melancholicus) is recorded. In the case of one intensively studied host, the Yellow‐hooded Blackbird, cowbird parasitism had a minimal negative effect on the host's reproductive success. Reproductive equilibrium in this study seemed to be maintained by behavioural adaptations of host and parasite to each other. The stable pattern of host choice by Shiny Cowbirds in Trinidad and Tobago may not develop elsewhere in the West Indian region. Before the cowbird's expansion in the West Indies, potential hosts had no prior experience of brood parasites. Consequently, the island bird populations are unlikely to have evolved defensive strategies and thus may be more vulnerable to reproductive failure as a result of cowbird parasitism, precluding the development of a stable system at this point in time.

Anacroneuriaof Trinidad and Tobago (Plecoptera: Perlidae)

Two species of Anacroneuria occur on the islands of Trinidad and Tobago. A. aroucana Kimmins, 1948, appears to be endemic to Trinidad while A. isleta sp. n., occurs on Tobago. Both A. isleta and A. aroucana appear to have sister species on the South American mainland.

Does preschool curriculum make a difference in primary school performance: Insights into the variety of preschool activities and their effects on school achievement and behaviour in the Caribbean Island of Trinidad; Cross sectional and longitudinal evidence∗

Preschool education is an important and much studied topic in developed countries, and of growing importance in the third world. Studies exploring preschool experience have noted positive effects when comparing children with access to preschool versus children without access, and effects of particular curriculum approaches over the length of primary schooling. This study adopts a focused sample, cross‐sectional design to explore the types of preschool experience available (denoted by types of preschool activities which equate broadly to curriculum approaches) and whether variation in preschool experience affects core curriculum (English, science, mathematics) performance and classroom behaviours throughout the years of primary schooling in Trinidad and when children complete their primary education in the form of a national ‘common entrance examination’ for entry into a stratified secondary school system. Results show that a large majority of the sampled children attended preschool and that most of the pr...

Project Trinidad

The first intercontinental satellite communication link, which involved the NASA Echo I balloon, a transmitting station on the Island of Trinidad, and a receiving station at Floyd, NY, is discussed. Rome Air Development Center (RADC) experimental stations were set up using a great deal of ingenuity and makeshift equipment and on a very small budget. Much of the equipment was salvaged from unrelated systems, while some was hand-built for this project. The implementation of the system, the testing of the system using moon bounce, the first orbital launch of the Echo I balloon, and the early difficulties encountered in the project are reviewed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Suicide Behaviour in the Caribbean

There have been relatively few publications on suicide in the Caribbean. Some of the earliest studies came out of the twin island of Trinidad & Tobago and later on from Guyana and Suriname. It was the ingestion of agro-chemicals by the East Indian population that might have stimulated the interest in those countries. The rate of suicide attempts in the Caribbean has been steadily increasing. Hospital records have confirmed this, but it would appear that in those countries with a high East Indian population that hospitalization has been mainly for ingestion of poisons. In those with a low East Indian population, the Afro-Caribbean has been overdosing with analgesics or benzodiazepines. Those who kill themselves continue to be male in mid-adulthood, but ingestion of agro-chemicals is now far more prevalent than hanging. It is probably because much less preparation is needed for ingestion than for hanging and it is now common knowledge that survival is rare after paraquat ingestion.

MITOCHONDRIAL DNA SEQUENCE VARIATION AMONG NATURAL POPULATIONS OF THE TRINIDAD GUPPY, POECILIA RETICULATA.

Guppies were sampled from eight populations representing four river drainage basins in northern Trinidad, and from one population on the nearby island of Tobago. For each individual, a 465 base pair (bp) segment of the control region of the mitochondrial genome was sequenced. The resulting DNA sequences were subjected to sequence divergence calculations and the populations were linked by maximum parsimony analysis to determine their phylogenetic relationships. Mitochondrial DNA (mtDNA) sequence variation was found both within and between river drainages, correlated with the geographic features of northern Trinidad. The variation observed exists primarily between drainages, particularly between the Oropuche drainage and all other Trinidad drainages examined. Estimates of time of divergence between guppy populations of different drainages, based on mtDNA sequence variation, ranged from 100,000 to 200,000 for the most recently separated populations and from 600,000 to 1.2 million years between the Oropuche populations and all others examined. Examination of fish from northeastern South America will be required to determine whether these populations differentiated in their present locations or were the result of separate invasions of Trinidad from different Venezuelan sources. However, genetic isolation of these populations appears to predate the current physical separation of the island of Trinidad from the Venezuelan mainland.

Life History of Poecilia picta (Poeciliidae) from the Island of Trinidad

We describe the life history of Poecilia picta from four collections made at three localities in Trinidad. Dependent variables include the number and size of offspring, the average size of mature males, the size distribution of reproducing females, and the mode of reproduction. Poecilia picta contain only one brood of developing young at a time (i.e., do not have superfetation). The young lose approximately 36% of their dry mass during development, implying that this species is lecithotrophic or that there is no maternal provisioning after the eggs are fertilized. We compared the life history with that of the closely related P. reticulata (guppies) from three types of communities in Trinidad and found that P. picta has a life history very similar to guppies which co-occur with Crenicichla alta (a predator on adult size classes of guppies) and other predators. This means that they give birth to relatively many, small young and have high reproductive allotments. This comparison is consistent with the similar assemblage of predators found at all three P. picta localities and suggests that predation may have played a role in the evolution of P. picta's life history. Variation in life-history patterns in P. picta from different localities was similar to the pattern of variation observed in guppies reared on different levels of food availability in the laboratory, suggesting that differences among localities' food availability may account for some of this variation. Specifically, high food availability is associated with increased body size, litter size, and reproductive allotment; this same pattern accounts for the significant differences in life histories seen among the four P. picta collections.

Distribution of selected heavy metals in skin and muscle of five tropical marine fishes

An investigation was carried out to determine the effect of tissue type, tissue location and size of fish on the heavy metal levels of five species of fish found in the marine environment of the tropical island of Trinidad. The study was conducted with the fish species Lutjanus synagris, Micropogon furnieri, Cynoscion leiarchus, Caranx hippos and Scomberomorus brasiliensis, and focused on the muscle and skin tissues of the fillet of these fish. The metals Fe, Zn, Cu, Ni, Pb, Cd and Cr were analysed by atomic absorption spectrophotometry after acid digestion of the tissues, but only Fe, Zn and Cu were detected. Skin tissue showed elevated levels of metals in comparison with muscle tissue, and significant differences in metal levels with respect to tissue location in skin, and varying effects of size on both muscle and skin metal levels in the different species, were found. These results emphasize the need for careful sampling of tissue in these fish species if reliable data on heavy metal levels are to be generated.

Fruit and Consumer Differences in Three Species of Trees Shared by Trinidad and Tobago

Fruit and Consumer Differences in Three Species of Trees Shared by Trinidad and Tobago

The Barred Antshrike (Thamnophilus doliatus) on Trinidad and Tobago: habitat niche expansion of a generalist forager.

The Barred Antshrike (Thamnophilus doliatus) is the most abundant insectivorous foliage-gleaning vertebrate in both closed rain forest and second growth on the island of Tobago. However, it occurs only in second growth on the larger neighbor island of Trinidad and on the neotropical mainland.Habitat niche expansion into Tobago forest has been facilitated by several behavioral traits which set the antshrike apart from other foliage-gleaners of forest and second growth on Tobago. The antshrike captures a higher diversity of foliage, branch & trunk, and terrestrial arthropods. It forages over a wider range of heights and under a wider variety of crown cover situations than any of its closest ecological counterparts on Tobago. The antshrike also takes a wider range of prey sizes and regularly uses additional food sources, including fruit and ants, not taken by other guild members. The broad foraging niche of the antshrike enables it to breed during many times of the year when other narrower-niched foliage-gleaners do not.On Trinidad, although the most common foliagegleaner in second growth, the antshrike was not observed in adjacent closed rain forest. Several facts suggest that diffuse competition may be excluding antshrikes from Trinidad forest: 1) a general pattern of rarity or absence in other parts of its range where there are more guild members; 2) more species and individuals of foliagegleaners with an overall higher biomass in Trinidad forest than in Tobago forest; 3) foliage arthropod resources are significantly (1.7x) lower in Trinidad forest than Tobago forest, suggesting that Trinidad forest guild members may be depressing the quantity of important resources for antshrikes; and 4) Trinidad forest species with the highest foraging similarity to antshrikes have a greater precentage of prey captures comprised of relatively specialized attack behaviors than do Tobago forest antshrikes.Foraging generalists like the Barred Antshrike appear to expand or contract their habitat niches depending upon the number of ecologically similar species in a given habitat. They may occur in high densities in habitats typically foreign to them provided competitors are few and there is sufficient food to supply their catholic requirements.

Comparative ecophysiology of CAM and C3 bromeliads. II. Field measurements of gas exchange of CAM bromeliads in the humid tropics

Abstract The results described represent the first detailed measurements of gas exchange of epiphytic plants with crassulacean acid metabolism (CAM) in the humid tropics. A portable steady‐state CO2 and H2O porometer was used to measure net exchange rates of CO2 and H2O vapour (JCO2, JH2O), leaf temperature (T1), air temperature (TA), air relative humidity (RH) and photosynthetically active radiation (PAR) for bromeliads in the field during the dry season in February and March 1983 on the tropical island of Trinidad. Different lengths of tubing (up to 25 m) were used so that the gas exchange could be measured of bromeliads in situ in their epiphytic habitats. Derived parameters such as leaf‐air water‐vapour‐concentration difference (Δw), water‐vapour conductance of leaves (g) and internal CO2 partial pressure (piCO2) could be calculated.The particular problems of making such measurements in the humid tropics due to high relative humidities and high dew‐point temperatures are discussed. The long and often broad, strap‐like leaves of bromeliads are well suited for measurements with the steady‐state porometer. It is shown that CAM activity varies along the length of individual leaves, and variability between different leaves is also demonstrated.The major phases of CAM, i.e. nocturnal stomalal opening, CO2 uptake and dark fixation as malic acid (Phase I), daytime stomatal closure and light‐dependent assimilation of CO2 derived from decarboxylation of the malic acid (Phase III), and late‐afternoon stomatal opening with direct light‐dependent assimilation of atmospheric CO2 (Phase IV) were all clearly shown by CAM bromeliads in situ. Their expression and magnitude depended on the environmental conditions. An early‐morning peak of CO2 uptake as is characteristic of Phase II of CAM was not detected during the night‐day transition. A bromeliad intermediate between C3 and CAM, Guzmania monostachia, showed substantial net CO2 uptake in the early morning but no net uptake integrated over the whole of the night.

Screwworm (Diptera: Calliphoridae) myiasis in the southern Caribbean, and proposals for its management.

In a random sample of animal producers and animal health personnel, 33% of the respondents in Trinidad, 15% in Guyana, and 11% in Suriname recalled at least one case of human myiasis due to Cochliomyia hominivorax (Coquerel). During 1981, respondents in Suriname (88%), Guyana (85%), and Trinidad and Tobago (82%) found at least one case of myiasis in their livestock, mainly cattle, pigs, and dogs. Feral animals—e.g., jaguars—were also found to be infested. The initial wounds were mainly the umbilicus of neonates, whereas arbitrary cuts, castration wounds, and vampire bites were also affected. Fifty-three to 78% of all respondents examined their livestock daily for wounds and infestation by the screwworm. Daily examinations of livestock are now done as a result of the screwworm threat. Annual estimates of losses (in U.S. dollars) due to surveillance and medication ranged from 4.82 to 10.71 per animal. These national losses amounted to 0.30 million (Suriname), 1.02 million (Trinidad and Tobago), and 4.33 million (Guyana). Other losses, such as failure to thrive, reduction in milk production, and hide injury due to screwworm activity, were not available. Most producers found that the greatest infestation occurred in the wet season. Also, most (68 to 83%) found the screwworm to be second in importance to the Boophilus spp. ticks as a pest of livestock, but of greater significance than biting flies such as tabanids and stable flies. Eradication of the screwworm can be recommended for the islands of Trinidad and Tobago. Eradication for Suriname and Guyana seems feasible only on the 100-km wide coastal strips, where most human and livestock populations exist.

PROBLEMS IN THE USE OF GENETIC SIMILARITY TO SHOW RELATEDNESS.

Genetic heterogeneity from allozyme data in social mammals has received recent attention as a tool to show degree of relatedness among colony members. Whether one is considering a colonial anemone, a prairie bunchgrass, or a swarm of insects, the idea of using electrophoretic genetic heterogeneity as a tool to infer relatedness in social organisms is appealing. In many instances a naturally occurring aggregation may be readily observed, but relatedness among group members is known only by observing a population until a complete turnover of individuals occurs. For many long-lived species, or species with complex or obscure life cycles, this is impractical. Here we used data we have obtained from a social mammal to evaluate the use of electrophoretic genetic heterogeneity to determine relatedness. If social groups are kin groups, sociality may result from behaviors which favor the incorporation of known individuals, who are likely to be closely related, into the society and the rejection of strangers, who are likely to be unrelated or distantly related. Thus, sociality may result from kin selection and inclusive fitness (Hamilton, 1964; West Eberhard, 1975). Qualitative conditions that promote genetic heterogeneity among social groups and increase the relatedness of group members include: (1) the restriction of mate selection to those within the social group, (2) a low exchange rate of individuals among groups, and (3) preferential recruitment of juveniles into their natal group (McCracken and Bradbury, 1978). These criteria were used by McCracken and Bradbury in evaluating the kinship within colonies of phyllostomid bats on the island of Trinidad. They found that all juveniles dispersed from their natal colony, that recruitment into harems was random, and that harems and colonies were not heterogeneous at three allozyme loci. Thus they concluded that relatedness among colony members was low and sociality in this species at this location was not a result of kin selection. Here we consider the opposite case in which

"Ecological Release," Seasonal Variation in Food Supply, and the Hummingbird Amazilia Tobaci on Trinidad and Tobago

Resident populations of the Coppery—rumped Hummingbird, Amazilia tobaci, occupy the West Indian Islands of Trinidad and Tobago. Trinidad has 15 other hummingbird species, Tobago only 4 others. We predicted that A. tobaci on Tobago would have a broader feeding niche and a denser population than would A. tobaci on Trinidad. We monitored populations of Amazilia tobaci for 13 mo at study sites in the Arima Valley of northern Trinidad and in central Tobago. The two sites had nearly identical climates, and similar assemblages of flowers visited by hummingbirds. At both sites, food available to nectar—feeding birds varied &gt; 100 fold over the year. For 9 mo (December—August), neither A. tobaci population faced a severe food shortage. From September through November, nectar was scarce at both sites. During this period, Tobago A. tobaci faced only two other, uncommon species of nectar—feeding birds, which had very different feeding habits. The Trinidad population endured the food shortage along with six other hummingbird species. At this time Tobago A. tobaci utilized variously sized and shaped flowers of numerous plant species. On Trinidad, where many flowers were visited by the other hummingbird species, A. tobaci primarily used flowers that matched their bill size, which resulted in narrower feeding niche than on Tobago. These effects of "ecological release" on Tobago were apparent for only 3 mo, however, and when data for an entire year are compared there were few statistically significant contrasts between Tobago and Trinidad populations. At both sites, niche (diet) breadth responded in density—dependent fashion to changes in food density, broadening with high densities of A. tobaci relative to food, narrowing when food was abundant. Median values for niche breadth, population density, and population density per unit resource were not significantly greater on Tobago than on Trinidad. Ecological differences between the two populations during the food shortage may be linked to a phenotypic difference. We found no increase on Tobago in the intrapopulation variance of any morphological parameter important to feeding. However, Tobago, A. tobaci had longer wings than Trinidad conspecifics, resulting in lower wing disc loadings (ratio of body mass to area swept out by the wings). Among hummingbirds in general, low wing disc loading indicates a capacity to forage at a wide variety of flowers, which suggests that the Tobago population has undergone "within—phenotype nich expansion." Two experiments showed that individuals from the Tobago population of A. tobaci used a wide variety of artificial flowers, and a wide range of flower densities in field manipulations, than did conspecifics from Trinidad. The results suggest that occasional food shortages play a crucial role in the ecology and evolution of island populations, and that this might be undetected in short—term studies.