On the Use of Recycled Asphalt and Trinidad Lake Asphalt(TLA)for the Preparation of High Modulus Asphalt Concrete

Rutting of asphalt pavement occurs earlier and is more serious under the increasingly heavy traffic load conditions that can be found in subtropical monsoon climate regions.High modulus asphalt concrete(HMAC)with excellent anti-rutting and anti-fatigue properties is generally used to mitigate this issue.Given the relatively high cost of the additives used in this type of asphalt,in this study the feasibility of using recycled asphalt mixture(RAP)and Trinidad lake asphalt(TLA)for the preparation of HMAC is considered.The mineral composition of the RAP is first analyzed,then the TLA modified asphalt with different levels of RAP content is used to assess the effect of RAP on the performance of the mixture.Finally,the high-temperature rheological properties of extracted bitumen and the adhesion characteristic between mineral and bitumen are analyzed.The results show that after RAP combustion,the yellowish and greyish minerals display different alkalinity values,while the greyish mineral exhibits an improved ability to combine with bitumen.Thus,RAP can significantly enhance the high-temperature rutting resistance of TLA modified asphalt mixtures.The aged bitumen in RAP makes the mixed binder harder and improves its rheological properties at high temperatures.

Practice, Behavior, Knowledge and Awareness of Food Safety among Secondary &Tertiary Level Students in Trinidad, West Indies

The aim of this study was to assess the level of food safety practice, knowledge, behavior and awareness among n = 205 Trinidadian students (mean age 18±) enrolled within the education system in the Republic of Trinidad and Tobago, West Indies and to explore the association between these variables and the demographic and educational characteristics. To address these concerns, participants enrolled within the secondary (high school) and tertiary (university) institutions in Trinidad were questioned (16 questions) on food buying habits, preparation, attitudes, behaviors, knowledge and awareness. The data were analyzed using SPSS for descriptive, frequency distribution and percentages. Pearson chi square tested the association between food safety behaviors and awareness in relation to gender, age and educational level. Findings indicated that 76%of the students “always” washed their hands after touching raw chicken/meats and fish, while 50% utilized separate cutting boards/knives for raw chicken/meat and fish. Many students (68%) believed that it was “very safe” to only rinse cutting boards used for raw chicken/meat and fish. Others (10%) believed it was “very safe” to defrost foods outside the refrigerator, and 25% reported that it was “safe” to leave hot foods at room temperature for more than four hours. The level of food safety practice and behavior was higher (p < 0.05) among the female students at the secondary school level than those at the tertiary level. There was no difference in the median (20/45) and mode (25/45) scores for food safety behavior between the two educational groups but the difference (p < 0.01) was significant for awareness. Food safety practice, behavior and awareness skills of males at the secondary level were significantly lower (p < 0.01) than the females. These results strengthen the need for continuous educational programs to improve food safety awareness skills of Trinidadian students.

Fitting and evaluation of height-diameter models for Alnus japonica in La Trinidad, Benguet, Philippines

The study was conducted to develop height-diameter at breast height(HT-DBH) models for Alnus japonica in La Trinidad, Benguet,Philippines and evaluate their predictive capability.The six widely used nonlinear growth models that were selected in this study were the ChapmanRichards, Schnute, Modified logistic, Korf/Lundqvist,Weibull and Exponential. A total of 208 Alnus japonica trees were measured using standard diameter tape for DBH(1.3 m above the ground) and Vertex and transponder was used for the total height measurement. The performance of the developed models were evaluated using the fit statistics including coefficient of determination(R^2), root mean square error(RMSE), mean bias(ē), absolute mean difference(AMD), and Akaike Information Criterion(AIC). The lack-of-fit statistics was also performed for further evaluation of the performance of the models.Based on the evaluation criteria, all six models were able to determine the DBH-height relationships and fitted the data well. Using the rank analysis, the Weibull HT-DBH model had the best performance among the six commonly used nonlinear growth models. The results of this study will help forest managers especially in La Trinidad, Benguet to easily predict the total height using the Weibull model for Alnus japonica utilizing the DBH as the predicting variable.

Forecasting Emergency Paediatric Asthma Hospital Admissions in Trinidad and Tobago: Development of a Local Model Incorporating the Interactions of Airborne Dust and Pollen Concentrations with Meteorological Parameters and a Time-Lag Factor

Respiratory diseases such as asthma and rhinitis are multifaceted disorders which are exacerbated by various factors including: gender, age, diet, genetic background, biological materials, allergens (pollen and spores), pollutants, meteorological conditions and dust particles. It is hypothesized that, the number of valid physician diagnosed cases of paediatric asthma, which has resulted in emergency room visits in Trinidad can be expressed as a function of the magnitude of pollen counts, particulate matter (PM10), and selected meteorological parameters. These parameters were used to develop a 7-day predictive model for paediatric asthma admittance. The data showed no obvious, strong correlations between paediatric asthma admissions and dust concentrations, and paediatric asthma admissions and pollen concentrations, when considered in isolation or in a linear fashion. However, using polynomial regression analysis, which looked at combinations of interactions, a strong 7-day predictive model for paediatric asthma admissions, was developed. The model was tested against actual data collated during the study period and showed a strong correlation (R2 = 0.85) between the regression model and the actual admissions data.

The Asian Green Mussel <i>Perna viridis</i>(Linnaeus 1758): 20 Years after Its Introduction in Trinidad and Tobago

Invasive species are often characterised by the introduction of low numbers of individuals and a small genetic pool which could give rise to a population with a lower genetic diversity than the original population. Perna viridis was first reported on the west coast of Trinidadin1990 inthe Point Lisas Industrial estate. They may have been first introduced either as juvenile free floating mussels (spat) or as adults attached to the hulls of ships. This gregarious species spread rapidly throughout the Caribbean toVenezuela,KingstonHarbor(Jamaica) and by 1999 was reported inTampaBay(Florida). Genetic analysis was done on tissue samples fromTrinidadto determine the genetic similarity of newly collected specimens (2009) with archived specimens (collected 1994). Results suggest that there may not be any genetic variation in the population of Perna viridis, even approximately 20 years after initial colonization. These results suggest that there was no evidence of genetic bottlenecks in the population of P. viridis fromTrinidad.

The challenge of combatting non-communicable diseases in Trinidad: Access to hospital care

Chronic illnesses, or non-communicable diseases (NCDs), account for a growing number of deaths worldwide. The English-speaking Caribbean has the highest per capita burden of NCDs in the region of the Americas [1]. This paper presents an overview of hospital availability on the island of Trinidad in the West Indies and examines rates of NCDs as reported in hospital discharge summaries. The project integrates a Geographic Information System (GIS) with epidemiologic and bio-statistical data to provide essential spatial analysis not otherwise possible. It examines the island’s ability to effectively deliver treatment to residents with NCDs by providing a geographic perspective to public data published on the internet by the Trinidad-Tobago Ministry of Health and the Central Statistical Office. The study reveals a significant variability in several dimensions of access to health care.

Availability and accessibility of diabetes clinics on Trinidad: An analysis using proximity tools in a GIS environment

Non-communicable diseases (NCDs), account for a growing number of deaths worldwide. The English-speaking Caribbean has the highest per capita burden of NCDs in the region of the Americas [1]. This paper presents an overview of availability and accessibility based on clinic hours and physician fulltime equivalents (FTE) on the island of Trinidad devoted to diabetes and wound care. The project integrates a Geographic Information System (GIS) with epidemiologic and bio-statistical data to provide a necessary spatial analysis not otherwise possible. It examines the island’s ability to effectively deliver treatment to residents with diabetes by providing a geographic perspective to data published on the internet by the Trinidad-Tobago Ministry of Health and the Central Statistical Office. Results indicate a significant regional variability in both numbers of physicians and office hours devoted to diabetes treatment.

Social and Clinical Profiling among Chronic Alcohol Dependent Men and Women Attending AA Groups in Trinidad

Background: Alcoholics Anonymous (AA) is well established in Trinidad and serves as an indispensable modality in the rehabilitation of alcoholics. This study investigates the gender differences in socio-demographic characteristics and clinical presentation of AA members in Trinidad. Method: Data were collected along the following variables: age, gender, ethnicity, religion, age of onset of alcohol use, psychiatric diagnoses and intentions for seeking treatment. An investigation of 107 members attending AA groups in Trinidad was conducted and analyzed utilizing a demographic questionnaire and the Michigan Alcohol Screening Test (MAST). The Statistical Package for the Social Sciences (SPSS, Version 16) was used to conduct all statistical analyses. Results: The age of the sample ranged from 22 to 78 with a mean age of 48.01 Males dominated the sample, accounting for 68% (n = 73), while females were 32% (n = 34). In terms of Ethnicity, East Indians accounted for 62% (n = 65) of the sample, Africans 14% (n = 15), Mixed 16% (n = 17) and other 7% (n = 7). Religious constitution was dominated by Hindus 36% (n = 38), Roman Catholics 21% (n = 22), other 14% (n = 15), Presbyterian 10% (n = 11), Pentecostal 9% (n =10), Muslim 5% (n = 6) and Anglican 4% (n = 5). Results utilizing the t-test showed that mean scores for males versus females differed significantly from each other (t (1,105) = 2.11, p = 0.036) with males having a higher score on the MAST compared to females. Overall 14% of individu?als indicated to having a co-morbid psychiatric disorder of which 10.5% were depression. Conclusion: Significant dif?ferences existed between genders in the clinical presentation of alcohol dependence. The composition and structure of AA groups in Trinidad is fashioned on a male gender bias. There is a need to address specific gender issues in the treatment of female alcoholics.

COVID-19 and its effects upon orthopaedic surgery: The Trinidad and Tobago experience

The World Health Organisation(WHO)declared coronavirus disease 2019(COVID-19)a pandemic on March 11,2020.COVID-19 is not the first infectious disease to affect Trinidad and Tobago.The country has faced outbreaks of both Chikungunya and Zika virus in 2014 and 2016 respectively.The viral pandemic is predicted to have a significant impact upon all countries,but the healthcare services in a developing country are especially vulnerable.The Government of Trinidad and Tobago swiftly established a parallel healthcare system to isolate and treat suspected and confirmed cases of COVID-19.Strick‘lockdown’orders,office closures,social distancing and face mask usage recommendation were implemented following advice from the WHO.This approach has seen Trinidad and Tobago emerge from the second wave of infections,with the most recent Oxford COVID-19 Government Response Tracker report indicating a favourable risk of openness index for the country.The effects of the pandemic on the orthopaedic services in the public and private healthcare systems show significant differences.Constrained by shortages in personal protective equipment and inadequate testing facilities,the public system moved into emergency mode prioritizing the care of urgent and critical cases.Private healthcare driven more by economic considerations,quickly instituted widespread safety measures to ensure that the clinics remained open and elective surgery was not interrupted.Orthopaedic teaching at The University of the West Indies was quickly migrated to an online platform to facilitate both medical students and residents.The Caribbean Association of Orthopedic Surgeons through its frequent virtual meetings provided a forum for continuing education and social interaction amongst colleagues.The pandemic has disrupted our daily routines leading to unparalleled changes to our lives and livelihoods.Many of these changes will remain long after the pandemic is over,permanently transforming the practice of orthopaedics.

Fusion of a Mandibular Third Molar and a Distomolar in a Trinidadian Child: Report of a Rare Case Diagnosed Using CBCT

Double teeth refer to two teeth that are totally or partially joined by dentin and maybe their pulps. These developmental anomalies may be the result of either gemination or fusion. This is a case of a 15-year-old Indo-Trinidadian male who presented with the fusion of a mandibular third molar with a distomolar as an incidental finding. The patient had his general dental care provided by a paediatric dentist and was referred to an oral and maxillofacial radiologist, orthodontist, and oral surgeon for consultation. A Cone-beam CT was taken to supplement the plain film periapical and orthopantomogram radiographs. It showed the three-dimensional orientation of the double molar and the extent of joining. This is the first case of fusion of a mandibular third molar to a distomolar being reported in the Caribbean.

Characterization of Multidrug Resistant Escherichia coli Isolates Recovered from Humans and Chickens, Trinidad and Tobago

To characterize extended-spectrum beta-lactamase (ESBL) and extra-intestinal pathogenic Escherichia coli (ExPEC) associated virulence genes in E. coli isolates from chickens and humans in Trinidad and Tobago. This cross sectional study was conducted over a three-month period. A total of 471 E. coli isolates;160 from humans treated at a regional tertiary hospital and 311 from chicken caecal samples from “pluck shops” in Trinidad & Tobago were identified using both conventional and molecular microbiological methods. Phenotypic confirmation of ESBL producing E. coli isolates from humans was by Microscan system (Siemens, USA) while the double disk diffusion method was used for the chicken isolates. Polymerase chain reaction (PCR) analysis was used to determine the ESBL and ExPEC-associated virulence genes in representative human isolates and all chicken isolates. From the 311 chicken E. coli isolates, 49.2% (153/311) produced ESBL, while 56.3% (90/160) from humans were ESBL positive. All human and chicken ESBL isolates were 100% susceptible to carbapenems and aminoglycosides antimicrobials. PCR detected 21.1% blaCTX-M, 13.3% blaTEM and 7.8% blaSHV genes among E coli isolates from humans compared to 0.6% blaCTX-M and 48.6% blaTEM genes in chickens. PCR analysis revealed diverse virulence profiles among the isolates. There was a high occurrence rate of ExPEC-asso- ciated virulence genes in E. coli isolates from both humans and chickens. However, the CTX-M-1 genes were most predominant in humans while TEM occurred in chic- ken isolates. The diverse ESBL and virulence associated gene profiles encountered in E. coli isolates from humans and chickens on the surface depicts no similarity or relationships despite occurrence in both cohort groups. Therefore E. coli strains from chickens and humans require further investigation to determine their clonal relatedness or transmission in the country.

Knowledge, Attitude and Practice among Drivers in Trinidad, West Indies

Few studies have been conducted on the incidence and factors which contribute to road traffic collisions in Trinidad. In order to fill this gap in knowledge, we conducted knowledge, attitudes and practice (KAP) study among drivers to determine which factors contributed to these accidents. A questionnaire was developed and administered using a cross-sectional approach among 3000 persons living in 5 different areas of Trinidad. The collected data were analysed using SPSS version 22, t-test and multivariate analysis. Of the 2998 respondents, at least 572 (19.1%) had been involved in one or more road collisions. While only 46.7% of respondents always wore seat belts, approximately 93% believed strongly that their use was essential for safety—a 3-fold increase in that found in a previous study. The multiple regression analysis indicated that attitude and age were significantly associated with accidents and increased risk for accidents. The results showed that alcohol consumption, use of mobile phones while driving, speed, and age were significantly (p > 0.001) associated with accidents. In conclusion, most respondents were aware of traffic laws and regulations, but their knowledge and practice often diverged. However the improvement in attitude to seat-belt wearing suggests that a holistic driver education program may improve driver practice and adherence to the road traffic regulations in Trinidad.

Red Light Running in Trinidad

Red Light Running (RLR) has been associated with road traffic collisions in many jurisdictions across the world. The study aimed at evaluating the factors related to red light running (RLR) in Trinidad and Tobago that could be incorporated into policies that would aim to reduce this tendency and its related costs. Using data collected from the Traffic Unit of Trinidad and Tobago and three major intersections in the country, analysis was done on the impact of time of the day, age of the driver, ethnicity, gender, type of the vehicle, location and day of the week which are related to RLR. The results showed that the highest number of RLR occurs during rush hours in the morning and also in the evenings. Also, Indo-Trinidadian and male drivers display a higher tendency towards RLR. It was also established that some junctions have higher RLR rates than others and that Fridays have more RLR cases than all the other days of the week. These findings are very similar to those made in other countries such as the USA. The study has resulted in specific findings that can be used to improve traffic safety policies in the country.

Adjusting Second Moment Bias in Eigenspace Using Bayesian Empirical Estimators, Dirichlet Tessellations and Worldview I Data for Predicting Culex Quinquefasciatus Habitats in Trinidad

Temporally weighted regression models with a spatial autoregressive component may estimate nonlinearities in spatiotemporal-sampled data of Culex quinquefasciatus, a major vector of West Nile Virus (WNV) which can help implement control strategies by determining optimal predictors associated to prolific habitats. The design of this kind of mixed model can specifically incorporate spatial autocorrelation whilst including the influence of other aspatial predictor variables. Currently, the lack of an estimation theory that allows for het- eroscedasticity and corresponding joint hypothesis testing in the presence of spatial dependence in georefer- enced Cx. quinquefasciatus habitat data is a serious shortcoming in WNV research. In this paper we used spatially lagged and simultaneous autoregressive models based on multiple predictor variables of immature Cx. quinquefasciatus and Worldview 1 (WV-1) data to help implant a remote habitat-based surveillance sys- tem in Trinidad. Initially, we used Geomatica Ortho Engine? v. 10.2 for extracting a Digital Elevation Model (DEM) from the WV-1 raw imagery. Results of the DEM analyses indicated a statistically significant inverse linear relationship between total sampled Cx. quinquefasciatus data and elevation (m) (R2 = -0.439;p < 0.0001), with a standard deviation of 10.41. Additional field-sampled information was derived using data from an or-thogonal grid-matrix constructed in an ArcInfo 9.3? and overlaid onto the WV-1 data. A unique identifier was placed in the centroid of each grid cell. Univariate statistics and Poisson regression models were then generated using the georeferenced covariates in SAS/GIS?. Coefficient estimates were also used to define expectations for prior distributions in a Bayesian estimation matrix using Markov Chain Monte Carlo (MCMC) specifications. A spatial residual trend analyses was then performed using autocorrelation indices which linked tabular data in SAS PROCLMIXED? with the egg-raft count data in ArcInfo?. The estimation matrix identified prolific habitats based on the covariate distance to the nearest house. An Ordinary kriged-based interpolator was then constructed in Geostatistical Analyst Extension of ArcGIS 9.3? based on the adjusted Bayesian estimates. For total Cx. quinquefasciatus egg-raft count, first order trend was fitted to the semivariogram at a partial sill of 5.931 km, nugget of 6.374 km, lag size of 7.184 km, and a range of 31.02 km using 12 lags. We assessed the performance accuracy of the interpolation procedures based on the magnitude and distribution of errors between observed and model-predicted values using Voroni tessella- tions. These residuals divided the space between the individual georeferenced Cx. quinquefasciatus habitats by XY coordinates in 2-dimenisional space which revealed that the geophysical parameter error residuals in the interpolation model were within normal statistical limitations. Newer GIS software and WV-1 data can generate highly accurate predictive Cx. quinquefasciatus habitat distribution models which can target prolific habitats of based on field-sampled count data. Our results suggest it may be unnecessary to manage all Cx. quinquefasciatus habitats to obtain significant reductions in incidence and prevalence of WNV in Trinidad.

TLA改性沥青路面施工质量控制技术研究

从TLA改性沥青拌和质量控制、TLA改性沥青混合料拌和质量控制以及改性沥青混合料运输质量控制等方面分析了沥青混合料质量控制的关键措施。通过摊铺底层质量、摊铺温度控制以及摊铺设备选择等方面对改性沥青路面摊铺质量控制关键措施进行了研究;通过有效压实时间和压路机合理组合以及压路机振幅选择策略等方面对TLA改性沥青路面压实质量进行了分析研究。

灰分对特立尼达湖沥青改性沥青混合料路用性能的影响

与石油沥青相比,特立尼达湖沥青(TLA)中含有较高的矿物质(灰分)。分析了不同灰分含量的TLA对改性沥青混合料基本性能的影响,在此基础上确定合理的灰分含量范围,为控制天然沥青灰分沉淀离析提供了参考。

TLA复合改性沥青混合料路用性能研究

针对TLA的特性研究TLA复合改性沥青的掺配工艺、掺配比例,同时通过沥青混合料性能试验,研究掺配湖沥青对混合料高、低温及强度性能的影响,发现动稳定度较SBS改性沥青提高71 4%,且总变形量明显减少,低温弯曲破坏应变提高20%,劈裂强度提高43 8%,另外通过AAPA进行沥青加铺层反射裂缝试验研究发现混合料的疲劳寿命提高57 4%。结果表明,TLA复合改性沥青在混合料高温性能、强度性能以及疲劳性能等方面都得到了良好的改善。因此湖沥青是一种性能良好的沥青改性材料,有较好的应用前景。

煤与FCC油浆共处理重质产物对道路沥青改性作用的评价

依据美国ASTM D5710-95和英国BSI BS 3690对Trinidad湖沥青(TLA)的评价标准,以及中华人民共和国行业标准JTG F40-2004《公路改性沥青路面施工技术规范》对改性沥青混合料和SBS类(I类)改性沥青储存稳定性的技术要求,对比同样试验条件下TLA改性沥青的特性,评价了煤与FCC油浆共处理所得重质产物对道路石油沥青的改性作用。结果表明,在400℃、10 MPa H2压力条件下所得的重质产物(CSA)对试验用90#基质沥青的改性作用与TLA的改性作用相似,满足上述各标准的指标要求;CSA改性沥青的混合料具有较高的极限拉伸应变值,即具有较好的弯曲性能,显示了更加优良的低温抗裂性能。

TLA改性沥青在沧黄高速公路中的应用研究

研究了特立尼达湖沥青(TLA)改性沥青的性能以及在国内外的应用状况,详细分析了TLA改性沥青在沧黄高速公路中的制备以及施工方案。检测结果表明:TLA改性沥青混合料具有优良的高温性能、低温性能以及水稳定性,是一种很好的沥青改性材料。它对于大交通量、重载作用下的公路沥青路面,有广阔的应用前景。