Background Studies for the Neutral Current Detector Array in the Sudbury Neutrino Observatory

An array of 3He-filled proportional counters will be used in the Sudbury Neutrino Observatory to measure the neutral-current interaction of neutrinos and deuterium. We describe the backgrounds to this detection method.Comment: Accepted for publication in the proceedings of TAUP99. 2 page

Contraction Bidimensionality: the Accurate Picture

We provide new combinatorial theorems on the structure of graphs that are contained as contractions in graphs of large treewidth. As a consequence of our combinatorial results we unify and significantly simplify contraction bidimensionality theory -- the meta algorithmic framework to design efficient parameterized and approximation algorithms for contraction closed parameters

Assessing the validity of the Triage Risk Screening Tool in a third world setting

Background: Social risk is rarely evaluated in older emergency department (ED) patients, although its identification can reduce re-attendance. Objectives: This study assessed the diagnostic accuracy of the Triage Risk Screening Tool (TRST) in the ED of a developing country. Methods: The diagnostic accuracy of TRST to detect elders at risk was compared to routine clinical evaluation, using a comprehensive evaluation by an experienced social worker as the ‘gold standard’. The inter-rater reliability of the TRST was assessed on a separate cohort of patients prior to the main study. Results: The sensitivity of the TRST was 94.7% vs 55.6% for physician assessment (p = 0.025). The TRST had good inter-rater reliability (Cohen’ Kappa = .882), and physicians found it easy to use. Conclusion: The TRST provides a rapid means of assessing risk in older ED attenders. This study confirmed the validity of this screening tool in a third world setting

Depression in diabetic patients presenting to the emergency department in Trinidad and Tobago – a hidden epidemic

The likelihood of depression in diabetics presenting to the Emergency Department in developing countries is unknown. The aim of this study was to determine the prevalence of undiagnosed depression among diabetic patients presenting to the Emergency Department in Trinidad and Tobago, and to determine the risk factors associated with depression in these patients. The prevalence of depression was 46.2%, of which 76.1% had mild depression, 20.6% moderate depression and 3.3% severe depression. Depressed patients were more likely to be Indo Trinidadian (69.7%), married (61.8%) and working in the public sector (42.3%). Factors independently associated with depression included lower education level (p=0.003), and a history of co-existing heart disease (p=0.048), myocardial infarction (p=0.04) or other co-morbidities (p=0.010). Depressed patients had higher HbA1c% values (p<0.0001), and were less likely to adhere to meal plans (p=0.015) and exercise regimes (p=0.028). Depression is an unrecognised epidemic among diabetics in the Trinidad and Tobago. This study suggests that screening for depression among diabetics in the Emergency Department may be a useful method of identifying these patients. Additionally, the association between poor diabetic control and depression in these patients suggests the need for more research into this phenomenon

Factors affecting mortality in major trauma patients in Trinidad and Tobago – a view from the developing world

Background: There is little data on major trauma in the developing world. This study investigated the characteristics and outcomes of seriously injured patients in Trinidad and Tobago, using TRISS methodology. Conclusion: Multiple factors influence mortality in major trauma patients in Trinidad and Tobago, including age, co-morbidities and injury mechanism. TRISS methodology accurately predicted survival in this population. A multi-centre trial is required to validate these findings

Falls in Older People: Comparing Older and Younger Fallers in a Developing Country

Purpose While falls are common in older people, causing significant mortality and morbidity, this phenomenon has not been extensively studied in the Caribbean. This study aimed to compare falls in older and younger people in this setting. Methods We conducted a prospective observational study of older trauma patients in Trinidad, comparing older and younger patients sustaining falls. Results 1432 adult trauma patients were included (1141 aged 18 - 64 years and 291 aged 65 years and older). Older fallers were more likely to be female (66.7% vs 47.2%; p <.001), suffer from multiple pre-existing diseases (24.7% vs 2.4%; p <.001) and take multiple medications (16.1% vs 0.8%; p <.001). They also sustained more severe injuries and presented with higher acuity than younger fallers. Admission rates were higher among older fallers (29.9% vs 13.1%; p <.001). Conclusions In our study, older patients who fell were a distinct group from younger falls victims, with unique demographic, clinical and injury related characteristics. Their increased risk of injury within the home, coupled with their propensity for more severe injuries made them a high risk patient group. More research is needed to better understand this patient group and plan specific preventive interventions

Are older fallers different? Comparing older fallers and non-fallers in a developing country

Objectives: Falls are common in older people, causing significant mortality and morbidity, but little is known about this phenomenon in developing countries. This study aimed to investigate falls in older people in the developing world, comparing fallers with other trauma patients. Methods: We conducted a prospective observational study of older trauma patients in Trinidad over a four-month period, comparing falls victims with other trauma patients, in relation to their demographic, pre-morbid and injury characteristics. Results: A total of 439 older trauma patients (aged 65 years) were included. Fallers were older (median age 75 years (interquartile range 65–89 years) vs. 70 years (interquartile range 65–79 years) in non-fallers). Overall, 65.2% of fallers were female, compared to 43.7% of non-fallers. Fallers were more likely to suffer from multiple pre-existing diseases, with 29.8% having comordibities, compared to 9.7% of non-fallers. Fallers were also more likely to be on multiple medications: 7.1% were on five medications, compared to no non-fallers. Fallers also sustained more severe injuries and presented with higher acuity than non-fallers. Admission and referral rates were higher among fallers compared to other trauma patients (59.9% vs. 30.4%). Conclusions: Older patients who fall are a distinct group from other older trauma patients, with unique demographic, clinical and injury-related characteristics. This information is useful in planning preventive and management strategies for these patients

Polypharmacy and potential drug-drug interactions in emergency department patients in the Caribbean

Background Potential Drug–Drug Interactions (DDI) account for many emergency department visits. Polypharmacy, as well as herbal, over-the-counter (OTC) and combination medication may compound this, but these problems are not well researched in low-and-middle-income countries. Objective To compare the incidence of drug–drug interactions and polypharmacy in older and younger patients attending the Emergency Department (ED). Setting The adult ED of a tertiary teaching hospital in Trinidad. Methods A 4 month cross sectional study was conducted, comparing potential DDI in older and younger patients discharged from the ED, as defined using Micromedex 2.0. Main outcome measure The incidence and severity of DDI and polypharmacy (defined as the use of ≥5 drugs simultaneously) in older and younger patients attending the ED. Results 649 patients were included; 275 (42.3%) were ≥65 years and 381 (58.7%) were female. There were 814 DDIs, of which 6 (.7%) were contraindications and 148 (18.2%) were severe. Polypharmacy was identified in 244 (37.6%) patients. Older patients were more likely to have potential DDI (67.5 vs 48.9%) and polypharmacy (56 vs 24.1%). Herbal products, OTC and combination drugs were present in 8, 36.7 and 22.2% of patients, respectively. On multivariate analysis, polypharmacy and the presence of hypertension and ischaemic heart disease were associated with an increased risk of potential DDI. Conclusion Polypharmacy and potential drug–drug interactions are common in ED patients in the Caribbean. Older patients are particularly at risk, especially as they are more likely to be on multiple medications. The association between herbal medication and polypharmacy needs further investigation. This study indicates the need for a more robust system of drug reconciliation in the Caribbean

Electronic structure and ferroelectricity in SrBi2Ta2O9

The electronic structure of SrBi2Ta2O9 is investigated from first-principles, within the local density approximation, using the full-potential linearized augmented plane wave (LAPW) method. The results show that, besides the large Ta(5d)-O(2p) hybridization which is a common feature of the ferroelectric perovskites, there is an important hybridization between bismuth and oxygen states. The underlying static potential for the ferroelectric distortion and the primary source for ferroelectricity is investigated by a lattice-dynamics study using the Frozen Phonon approach.Comment: 17 pages, 7 figures. Phys. Rev. B, in pres