374 research outputs found

    Geographical information retrieval with ontologies of place

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    Geographical context is required of many information retrieval tasks in which the target of the search may be documents, images or records which are referenced to geographical space only by means of place names. Often there may be an imprecise match between the query name and the names associated with candidate sources of information. There is a need therefore for geographical information retrieval facilities that can rank the relevance of candidate information with respect to geographical closeness of place as well as semantic closeness with respect to the information of interest. Here we present an ontology of place that combines limited coordinate data with semantic and qualitative spatial relationships between places. This parsimonious model of geographical place supports maintenance of knowledge of place names that relate to extensive regions of the Earth at multiple levels of granularity. The ontology has been implemented with a semantic modelling system linking non-spatial conceptual hierarchies with the place ontology. An hierarchical spatial distance measure is combined with Euclidean distance between place centroids to create a hybrid spatial distance measure. This is integrated with thematic distance, based on classification semantics, to create an integrated semantic closeness measure that can be used for a relevance ranking of retrieved objects

    Eliminating Ditransitives

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    Abstract. We discuss how higher arity verbs such as give or promise can be treated in an algebraic framework that admits only unary and binary relations and does not rely on event variables

    Association between Deepwater Horizon oil spill response and cleanup work experiences and lung function

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    Introduction: Oil spill response and cleanup (OSRC) workers had potentially stressful experiences during mitigation efforts following the 2010 Deepwater Horizon disaster. Smelling chemicals; skin or clothing contact with oil; heat stress; handling oily plants/wildlife or dead animal recovery; and/or being out of regular work may have posed a risk to worker respiratory health through psychological stress mechanisms. Objective: To evaluate the association between six potentially stressful oil spill experiences and lung function among OSRC workers 1–3 years following the Deepwater Horizon disaster, while controlling for primary oil spill inhalation hazards and other potential confounders. Methods: Of 6811 GuLF STUDY participants who performed OSRC work and completed a quality spirometry test, 4806 provided information on all exposures and confounders. We carried out complete case analysis and used multiple imputation to assess risk among the larger sample. Potentially stressful work experiences were identified from an earlier study of these workers. The lung function parameters of interest include the forced expiratory volume in 1 s (FEV1, mL), the forced vital capacity (FVC, mL) and the ratio (FEV1/FVC, %). Results: On average, participants in the analytic sample completed spirometry tests 1.7 years after the spill. Among workers with at least 2 acceptable FEV1 and FVC curves, workers with jobs that involved oily plants/wildlife or dead animal recovery had lower values for FEV1 (Mean difference: −53 mL, 95% CI: −84, −22), FVC (Mean difference: −45 mL, 95% CI: −81, −9) and FEV1/FVC (Mean difference: −0.44%, 95% CI: −0.80, −0.07) compared to unexposed workers in analyses using multiple imputation. Conclusions: Workers involved in handling oily plants/wildlife or dead animal recovery had lower lung function than unexposed workers after accounting for other OSRC inhalation hazards

    Exposure to Oil Spill Chemicals and Lung Function in Deepwater Horizon Disaster Response Workers

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    Objective: The aim of this study was to assess the relationship between total hydrocarbon (THC) exposures attributed to oil spill clean-up work and lung function 1 to 3 years after the Deepwater Horizon (DWH) disaster. Methods: We used data from the GuLF STUDY, a large cohort of adults who worked on response to the DWH disaster and others who were safety trained but did not work. We analyzed data from 6288 workers with two acceptable spirometry tests. We estimated THC exposure levels with a job exposure matrix. We evaluated lung function using the forced expiratory volume in 1second (FEV 1; mL), the forced vital capacity (FVC; mL), and the FEV 1 /FVC ratio (%). Results: Lung function measures did not differ by THC exposure levels among clean-up workers. Conclusion: We did not observe an association between THC exposure and lung function among clean-up workers 1 to 3 years following the DWH disaster

    Lung function in oil spill responders 4-6 years after the Deepwater Horizon disaster

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    Oil spill response and clean-up (OSRC) workers were exposed to hazardous airborne chemicals following the 2010 Deepwater Horizon disaster. The aim of this study was to evaluate lung function in workers 4–6 years following the disaster using a prospective cohort. Participants who completed two spirometry test sessions 1–3 years, and 4–6 years after the spill (N = 1,838) were included and forced expiratory volume in 1 s (FEV1; ml), forced vital capacity (FVC; ml), and ratio (FEV1/FVC; %) determined. Linear mixed models were utilized to estimate relationships between OSRC exposures and lung function 4–6 years after the spill and changes since the prior measurement. Despite suggestive reduced lung function at 1–3 years, at the 4–6-year exam workers with total hydrocarbon (THC) exposure 1–2.99 ppm and ≥3 ppm compared to those with ≤0.29 ppm exhibited higher FEV1 (β: 108 ml, 95% CI: 17, 198) and (β: 118 ml, 95% CI: 5, 232), respectively. Compared with support workers, those in higher exposed jobs displayed greater improvement in FEV1 between visits: cleanup on water (β: 143 ml, 95% CI: 35, 250), operations (β: 132 ml, 95% CI: 30, 234) and response (β: 149 ml, 95% CI: 43, 256). Greater FEV1 improvement was also associated with higher versus the lowest level THC exposure: 1–2.99 ppm (β: 134 ml, 95% CI: 57, 210) and ≥3 ppm (β: 205 ml, 95% CI: 109, 301). Lung function decrements seen shortly after the spill were no longer apparent 4–6 years later, with the greatest improvement among those with the highest exposures

    The guLF study: A prospective study of persons involved in the Deepwater horizon oil spill response and clean-Up

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    Background: The 2010 Deepwater Horizon disaster led to the largest ever marine oil spill. Individuals who worked on the spill were exposed to toxicants and stressors that could lead to adverse effects. Objectives: The GuLF STUDY was designed to investigate relationships between oil spill exposures and multiple potential physical and mental health effects. Methods: Participants were recruited by telephone from lists of individuals who worked on the oil spill response and clean-up or received safety training. Enrollment interviews between 2011 and 2013 collected information about spill-related activities, demographics, lifestyle, and health. Exposure measurements taken during the oil spill were used with questionnaire responses to characterize oil exposures of participants. Participants from Gulf states completed a home visit in which biological and environmental samples, anthropometric and clinical measurements, and additional health and lifestyle information were collected. Participants are being followed for changes in health status. Results: Thirty-two thousand six hundred eight individuals enrolled in the cohort, and 11,193 completed a home visit. Most were young (56.2% ≤ 45 years of age), male (80.8%), lived in a Gulf state (82.3%), and worked at least 1 day on the oil spill (76.5%). Workers were involved in response (18.0%), support operations (17.5%), clean-up on water (17.4%) or land (14.6%), decontamination (14.3%), and administrative support (18.3%). Using an ordinal job exposure matrix, 45% had maximum daily total hydrocarbon exposure levels ≥ 1.0 ppm. Conclusions: The GuLF STUDY provides a unique opportunity to study potential adverse health effects from the Deepwater Horizon oil spill

    Lung Function in Oil Spill Response Workers 1-3 Years after the Deepwater Horizon Disaster

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    Background: Little is known about the effects of inhalation exposures on lung function among workers involved in the mitigation of oil spills. Our objective was to determine the relationship between oil spill response work and lung function 1-3 years after the Deepwater Horizon (DWH) disaster. Methods: We evaluated spirometry for 7,775 adults living in the Gulf states who either participated in DWH response efforts (workers) or received safety training but were not hired (nonworkers). At an enrollment interview, we collected detailed work histories including information on potential exposure to dispersants and burning oil/gas. We assessed forced expiratory volume in 1 second (FEV 1; mL), forced vital capacity (FVC; mL), and the ratio (FEV 1 /FVC%) for differences by broad job classes and exposure to dispersants or burning oil/gas using multivariable linear and modified Poisson regression. Results: We found no differences between workers and nonworkers. Among workers, we observed a small decrement in FEV 1 (Beta, -71 mL; 95% confidence interval [CI], -127 to -14) in decontamination workers compared with support workers. Workers with high potential exposure to burning oil/gas had reduced lung function compared with unexposed workers: FEV 1 (Beta, -183 mL; 95% CI, -316 to -49) and FEV 1 /FVC (Beta, -1.93%; 95% CI, -3.50 to -0.36), and an elevated risk of having a FEV 1 /FVC in the lowest tertile (prevalence ratio, 1.38; 95% CI, 0.99 to 1.92). Conclusions: While no differences in lung function were found between workers and nonworkers, lung function was reduced among decontamination workers and workers with high exposure to burning oil/gas compared with unexposed workers

    Fine Particulate Matter and Lung Function among Burning-Exposed Deepwater Horizon Oil Spill Workers

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    BACKGROUND: During the 2010 Deepwater Horizon (DWH) disaster, controlled burning was conducted to remove oil from the water. Workers near combustion sites were potentially exposed to increased fine particulate matter [with aerodynamic diameter ≤2:5 lm (PM2:5 )] levels. Exposure to PM2:5 has been linked to decreased lung function, but to our knowledge, no study has examined exposure encountered in an oil spill cleanup. OBJECTIVE: We investigated the association between estimated PM2:5 only from burning/flaring of oil/gas and lung function measured 1–3 y after the DWH disaster. METHODS: We included workers who participated in response and cleanup activities on the water during the DWH disaster and had lung function measured at a subsequent home visit (n = 2,316). PM2:5 concentrations were estimated using a Gaussian plume dispersion model and linked to work histories via a job-exposure matrix. We evaluated forced expiratory volume in 1 s (FEV1; milliliters), forced vital capacity (FVC; milliliters), and their ratio (FEV1/FVC; %) in relation to average and cumulative daily maximum exposures using multivariable linear regressions. RESULTS: We observed significant exposure–response trends associating higher cumulative daily maximum PM2:5 exposure with lower FEV1 (p-trend = 0:04) and FEV1/FVC (p-trend = 0:01). In comparison with the referent group (workers not involved in or near the burning), those with higher cumulative exposures had lower FEV1 [−166:8 mL, 95% confidence interval (CI): −337:3, 3.7] and FEV1/FVC (−1:7, 95% CI: −3:6, 0.2). We also saw nonsignificant reductions in FVC (high vs. referent: −120:9, 95% CI: −319:4, 77.6; p-trend = 0:36). Similar associations were seen for average daily maximum PM2:5 exposure. Inverse associations were also observed in analyses stratified by smoking and time from exposure to spirom-etry and when we restricted to workers without prespill lung disease. CONCLUSIONS: Among oil spill workers, exposure to PM2:5 specifically from controlled burning of oil/gas was associated with significantly lower FEV1 and FEV1/FVC when compared with workers not involved in burning. https://doi.org/10.1289/EHP8930

    Associations between airborne crude oil chemicals and symptom-based asthma

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    Rationale: The 2010 Deepwater Horizon (DWH) oil spill response and cleanup (OSRC) workers were exposed to airborne total hydrocarbons (THC), benzene, toluene, ethylbenzene, o-, m-, and p-xylenes and n-hexane (BTEX-H) from crude oil and PM2.5 from burning/flaring oil and natural gas. Little is known about asthma risk among oil spill cleanup workers. Objectives: We assessed the relationship between asthma and several oil spill-related exposures including job classes, THC, individual BTEX-H chemicals, the BTEX-H mixture, and PM2.5 using data from the Gulf Long-Term Follow-up (GuLF) Study, a prospective cohort of 24,937 cleanup workers and 7,671 nonworkers following the DWH disaster. Methods: Our analysis largely focused on the 19,018 workers without asthma before the spill who had complete exposure, outcome, and covariate information. We defined incident asthma 1–3 years following exposure using both self-reported wheeze and self-reported physician diagnosis of asthma. THC and BTEX-H were assigned to participants based on measurement data and work histories, while PM2.5 used modeled estimates. We used modified Poisson regression to estimate risk ratios (RR) and 95% confidence intervals (CIs) for associations between spill-related exposures and asthma and a quantile-based g-computation approach to explore the joint effect of the BTEX-H mixture on asthma risk. Results: OSRC workers had greater asthma risk than nonworkers (RR: 1.60, 95% CI: 1.38, 1.85). Higher estimated THC exposure levels were associated with increased risk in an exposure-dependent manner (linear trend test p < 0.0001). Asthma risk also increased with increasing exposure to individual BTEX-H chemicals and the chemical mixture: A simultaneous quartile increase in the BTEX-H mixture was associated with an increased asthma risk of 1.45 (95% CI: 1.35,1.55). With fewer cases, associations were less apparent for physician-diagnosed asthma alone. Conclusions: THC and BTEX-H were associated with increased asthma risk defined using wheeze symptoms as well as a physician diagnosis
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