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1.
J Virol ; 95(24): e0165021, 2021 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-34586864

RESUMO

Foot-and-mouth disease (FMD) field studies have suggested the occurrence of simultaneous infection of individual hosts by multiple virus strains; however, the pathogenesis of foot-and-mouth disease virus (FMDV) coinfections is largely unknown. In the current study, cattle were experimentally exposed to two FMDV strains of different serotypes (O and A). One cohort was simultaneously infected with both viruses, while additional cohorts were initially infected with FMDV A and subsequently superinfected with FMDV O after 21 or 35 days. Coinfections were confirmed during acute infection, with both viruses concurrently detected in blood, lesions, and secretions. Staggered exposures resulted in overlapping infections as convalescent animals with persistent subclinical FMDV infection were superinfected with a heterologous virus. Staggering virus exposure by 21 days conferred clinical protection in six of eight cattle, which were subclinically infected following the heterologous virus exposure. This effect was transient, as all animals superinfected at 35 days post-initial infection developed fulminant FMD. The majority of cattle maintained persistent infection with one of the two viruses while clearing the other. Analysis of viral genomes confirmed interserotypic recombination events within 10 days in the upper respiratory tract of five superinfected animals from which the dominant genomes contained the capsid coding regions of the O virus and nonstructural coding regions of the A virus. In contrast, there were no dominant recombinant genomes detected in samples from simultaneously coinfected cattle. These findings inculpate persistently infected carriers as potential FMDV mixing vessels in which novel strains may rapidly emerge through superinfection and recombination. IMPORTANCE Foot-and-mouth disease (FMD) is a viral infection of livestock of critical socioeconomic importance. Field studies from areas of endemic FMD suggest that animals can be simultaneously infected by more than one distinct variant of FMD virus (FMDV), potentially resulting in emergence of novel viral strains through recombination. However, there has been limited investigation of the mechanisms of in vivo FMDV coinfections under controlled experimental conditions. Our findings confirmed that cattle could be simultaneously infected by two distinct serotypes of FMDV, with different outcomes associated with the timing of exposure to the two different viruses. Additionally, dominant interserotypic recombinant FMDVs were discovered in multiple samples from the upper respiratory tracts of five superinfected animals, emphasizing the potential importance of persistently infected FMDV carriers as sources of novel FMDV strains.


Assuntos
Portador Sadio/veterinária , Coinfecção/veterinária , Coinfecção/virologia , Vírus da Febre Aftosa/patogenicidade , Febre Aftosa/virologia , Infecção Persistente/veterinária , Animais , Anticorpos Antivirais/sangue , Portador Sadio/virologia , Bovinos , Doenças dos Bovinos/virologia , Vírus da Febre Aftosa/genética , Gado/virologia , Infecção Persistente/virologia , Sorogrupo
2.
J Am Water Works Assoc ; 113(9): 32-39, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34898678

RESUMO

Eleven utilities from across the United States were studied to understand the pandemic's effects on water consumption and utility revenues. Most utilities in the study saw an overall increase in water consumption with a rise in residential demand that offset declines in nonresidential demand. Most utilities in the study experienced increased revenues in 2020 compared with previous years, largely due to rate increases, inclining block rates, and an unusually warm summer. Water utilities' ability to adjust to fluctuating demand and changing revenue patterns is a testament to their sound financial practices.

3.
Environ Sci Technol ; 52(4): 2349-2358, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29383932

RESUMO

Demand for high-volume, short duration water withdrawals could create water stress to aquatic organisms in Fayetteville Shale streams sourced for hydraulic fracturing fluids. We estimated potential water stress using permitted water withdrawal volumes and actual water withdrawals compared to monthly median, low, and high streamflows. Risk for biological stress was considered at 20% of long-term median and 10% of high- and low-flow thresholds. Future well build-out projections estimated potential for continued stress. Most water was permitted from small, free-flowing streams and "frack" ponds (dammed streams). Permitted 12-h pumping volumes exceeded median streamflow at 50% of withdrawal sites in June, when flows were low. Daily water usage, from operator disclosures, compared to median streamflow showed possible water stress in 7-51% of catchments from June-November, respectively. If 100% of produced water was recycled, per-well water use declined by 25%, reducing threshold exceedance by 10%. Future water stress was predicted to occur in fewer catchments important for drinking water and species of conservation concern due to the decline in new well installations and increased use of recycled water. Accessible and precise withdrawal and streamflow data are critical moving forward to assess and mitigate water stress in streams that experience high-volume withdrawals.


Assuntos
Fraturamento Hidráulico , Arkansas , Biodiversidade , Desidratação , Ecossistema , Humanos , Estados Unidos
4.
Environ Sci Technol ; 51(5): 2563-2573, 2017 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-28220696

RESUMO

Rapid growth in unconventional oil and gas (UOG) has produced jobs, revenue, and energy, but also concerns over spills and environmental risks. We assessed spill data from 2005 to 2014 at 31 481 UOG wells in Colorado, New Mexico, North Dakota, and Pennsylvania. We found 2-16% of wells reported a spill each year. Median spill volumes ranged from 0.5 m3 in Pennsylvania to 4.9 m3 in New Mexico; the largest spills exceeded 100 m3. Seventy-five to 94% of spills occurred within the first three years of well life when wells were drilled, completed, and had their largest production volumes. Across all four states, 50% of spills were related to storage and moving fluids via flowlines. Reporting rates varied by state, affecting spill rates and requiring extensive time and effort getting data into a usable format. Enhanced and standardized regulatory requirements for reporting spills could improve the accuracy and speed of analyses to identify and prevent spill risks and mitigate potential environmental damage. Transparency for data sharing and analysis will be increasingly important as UOG development expands. We designed an interactive spills data visualization tool ( http://snappartnership.net/groups/hydraulic-fracturing/webapp/spills.html ) to illustrate the value of having standardized, public data.


Assuntos
Campos de Petróleo e Gás , Poços de Água , Meio Ambiente , Pennsylvania , Risco
5.
J Environ Manage ; 181: 353-362, 2016 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-27393942

RESUMO

Pennsylvania's rapid unconventional oil and gas (UOG) development-from a single well in 2004 to more than 6700 wells in 2013-has dramatically increased UOG waste transport by heavy trucks. This study quantified the amount of UOG waste and the distance it traveled between wells and disposal facilities on each type of road in each county between July 2010 and December 2013. In addition, the study estimated the associated financial costs to each county's road infrastructure over that period. We found that UOG wells produced a median wastewater volume of 1294 m(3) and a median of 89,267 kg of solid waste. The median number of waste-transport truck trips per well was 122. UOG wells existed in 38 Pennsylvania counties, but we estimated trucks transporting well waste traveled through 132 counties, including counties in West Virginia, Ohio, and New York. Median travel distance varied by disposal type, from 106 km to centralized treatment facilities up to 237 km to injection wells. Local roads experienced the greatest amount of truck traffic and associated costs ($1.1-6.5 M) and interstates, the least ($0.3-1.6 M). Counties with oil and gas development experienced the most truck traffic and incurred the highest associated roadway costs. However, many counties outside the active development area also incurred roadway repair costs, highlighting the extension of UOG development's spatial footprint beyond the active development area. An online data visualization tool is available here: www.nicholasinstitute.duke.edu/transportation-of-hydraulic-fracturing-waste.


Assuntos
Fraturamento Hidráulico , Resíduos Industriais , Gerenciamento de Resíduos/economia , Gerenciamento de Resíduos/métodos , Fraturamento Hidráulico/economia , Veículos Automotores , New York , Ohio , Campos de Petróleo e Gás , Pennsylvania , Resíduos Sólidos/estatística & dados numéricos , Águas Residuárias/estatística & dados numéricos , West Virginia
6.
J Am Vet Med Assoc ; 259(S1): 1-4, 2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35218635

RESUMO

In collaboration with the American College of Veterinary Radiology.


Assuntos
Radiologia , Animais , Humanos , Radiografia , Estados Unidos
7.
Microbiol Resour Announc ; 11(2): e0116721, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35112907

RESUMO

Here, we report the genome of bovine viral diarrhea virus 1 (BVDV-1) contaminating a continuous fetal bovine kidney cell line. The cell line (LFBK-αVß6) is used for the rapid isolation and serotyping of foot-and-mouth disease virus (FMDV). The sequence contains the full polyprotein-coding sequence and partial untranslated regions (UTRs).

8.
Microbiol Resour Announc ; 11(8): e0057422, 2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-35861523

RESUMO

We report the near full genome sequences of 18 isolates of foot-and-mouth disease virus serotype O and 6 isolates of serotype A obtained from outbreaks in Pakistan between 2011 and 2012. The scarcity of full-length FMDV sequences from this region enhances the importance of these genomes for understanding regional molecular epidemiology.

9.
Microbiol Resour Announc ; 11(8): e0057522, 2022 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-35862920

RESUMO

We report the nearly full genome sequences of 14 isolates of serotype A foot-and-mouth disease virus and 5 isolates of serotype O, which were obtained from subclinically infected Asian buffalo in Pakistan in 2011 to 2012. Sequences from subclinically infected animals are rare and complement the more commonly available sequences from clinical cases.

10.
Microbiol Resour Announc ; 11(6): e0031122, 2022 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35616404

RESUMO

We report the near-full-genome sequences of 49 isolates of serotype Asia-1 foot-and-mouth disease virus obtained from subclinically infected Asian buffalo in Islamabad Capital Region, Pakistan, in 2011 to 2012. Sequences from subclinically infected animals are exceedingly rare and complement the more commonly available sequences acquired from clinical cases.

11.
Microbiol Resour Announc ; 11(6): e0031222, 2022 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-35546123

RESUMO

We report the near-full-length genome sequences of 22 isolates of foot-and-mouth disease virus (FMDV) serotype Asia-1, lineage Sindh-08, obtained from foot-and-mouth disease outbreaks in Pakistan between 2011 and 2012. The scarcity of full-length FMDV sequences from this region enhances the importance of these new genomes for understanding the regional molecular epidemiology.

12.
Am J Obstet Gynecol ; 205(3): 246.e1-7, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21803321

RESUMO

OBJECTIVE: We sought to extend our prior observations and histopathologically characterize key metabolic enzymes (CYP1A1) with markers of oxidative damage in the placental sections from smokers. STUDY DESIGN: Placental specimens were collected from term singleton deliveries from smokers (n = 10) and nonsmokers (n = 10) and subjected to a detailed histopathological examination. To quantify the extent of oxidative damage, masked score-graded (0-6) histopathology against 4-hydroxy-2-nonenal (4-HNE) and 8-hydroxydeoxyguanisine (8-OHdG) was performed. Minimal significance (P < .05) was determined with a Fisher's exact and a 2-tailed Student t test as appropriate. RESULTS: We observed a significant increase in the presence of syncytial knots in placentas from smokers (70% vs 10%, P = .02). These gross observations were accompanied by a significant aberrant placental aromatic hydrocarbon metabolism (increased CYP1A1, 4.4 vs 2.1, P = .002) in addition to evidence of oxidative damage (4-HNE 3.4 vs 1.1, P = .00005; 8-OHdG 4.9 vs 3.1, P = .0038). CONCLUSION: We observed a strong association between maternal tobacco use and aberrant placental metabolism, syncytial knot formation, and multiple markers of oxidative damage.


Assuntos
Estresse Oxidativo/fisiologia , Placenta/metabolismo , Fumar , Adulto , Biomarcadores/metabolismo , Índice de Massa Corporal , Estudos de Coortes , Feminino , Humanos , Gravidez
13.
Aquat Toxicol ; 236: 105862, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34049114

RESUMO

Over the last 60 years, valuable progress was made in the standardization of environmental monitoring with model zooplankton. However, obligate dormancy in zooplankton life cycles is not yet considered in standardized toxicology methods. Most zooplankton from coastal and inland waters use dormancy as a critical ecological strategy, and exposure to toxicants during dormancy or resurrection from dormancy alters developmental patterning and hatching success. The present study accounts for this by using both standardized and novel toxicology assays to assess the impacts of coal ash contaminated sediments and water on development, hatching, and survivorship of model zooplankton. The results demonstrate that standardized assays with rotifer and cladoceran models detect no toxicity in surface water and sediment pore water from Lake Sutton, North Carolina, USA. By contrast, novel toxicity assays with cladoceran and anostracan models demonstrate that development and larval survivorship are negatively impacted by Lake Sutton water and sediment. Embryos of Artemia franciscana display developmental patterning and hatching aberrations that match those observed in previous studies with metals when hatched in filtered surface water or pore water after a period of anoxia-induced dormancy. Larval survivorship in Daphnia magna and A. franciscana also decreases when post-diapause embryos are hatched in the presence of sediment. The effects of whole sediment on larval survivorship are not explained by coal ash impacts on water pH. These data provide an explanation for the missing egg bank and historic community restructure in Lake Sutton. The data also demonstrate a need for standardized assays that include dormant life stages.


Assuntos
Monitoramento Ambiental , Poluentes Químicos da Água/toxicidade , Zooplâncton/fisiologia , Animais , Artemia , Daphnia/efeitos dos fármacos , Sedimentos Geológicos/química , Lagos/química , Larva , Estágios do Ciclo de Vida , Metais/toxicidade , Rotíferos , Zooplâncton/efeitos dos fármacos
14.
Sci Total Environ ; 723: 138074, 2020 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-32392683

RESUMO

The study of zooplankton communities in freshwater resources under anthropogenic pressures rarely includes the simultaneous assessment of dormant embryos in bottom sediments and active life-stages in the water column. A coastal lake with a history of coal-ash contamination and disruption by hurricanes provided an ideal opportunity to demonstrate the power of examining both dormant and active zooplankton. The primary objective of this study was to evaluate changes in structure of a multicellular zooplankton community that is under simultaneous pressure from anthropogenic pollution and hurricane-induced flooding. To evaluate change in community structure, the active zooplankton community in 2015 was compared to that observed in 1985. Shannon-Wiener and Simpson indices demonstrate that diversity of the active zooplankton community decreased during this 30-year span. In total, 31% of zooplankton species were lost, and new colonization accounts for 27% of species richness. Dominant species of all major taxonomic groupings changed. Because most zooplankton in freshwater lakes depend on dormant embryos to reestablish active populations after major disruptions, dormant embryos in the sediment "egg bank" were also quantified. Dormant cladoceran ephippia are present in bottom sediments, but dormant copepods and rotifers are missing. The existence of a dormant egg bank that is less diverse than the active community in a freshwater lake is unprecedented, and a depauperate "egg bank" would certainly impair community recovery after severe flooding from hurricanes. It is argued that a paradigm shift is needed in the ecological assessment of inland lakes in order to account for the critical role that dormant embryos (egg banks) play in freshwater zooplankton communities. Two challenges to achieving this are that 1. long-term monitoring is expensive and 2. data on dormant zooplankton are rarely available. This study provides an example of how to conduct such studies by leveraging historic data when long-term monitoring is not possible.


Assuntos
Copépodes , Rotíferos , Animais , Lagos , Zooplâncton
15.
Appl Nurs Res ; 22(2): 133-7, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19427576

RESUMO

BACKGROUND: Studies have identified prevalence rates of major depression in patients with cardiovascular disease to range from 16% to 23%, whereas 65% of patients report some symptoms after a myocardial event. Depression has been shown to be strongly related to overall poorer outcomes in patients with coronary artery disease. PURPOSE: The purpose of this pilot study was to assess the potential benefit of providing follow-up information regarding mental health resources to patients who had undergone cardiac catheterization and had reported significant levels of depression symptoms. Two methods of providing this follow-up information (personal telephone interaction and mailed-out written information) were compared. METHODS: As part of the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease registry, patients completed baseline questionnaires, including the 10-item Center for Epidemiologic Studies Depression (CES-D) Scale. Patients reporting a score of 10 or higher were randomly assigned to one of three groups. Group A patients were contacted by mail, whereas Group B patients were contacted through a telephone follow-up call by a nurse. Both groups received information regarding community- and hospital-based mental health resources. Six weeks after the initial contact, patients in Groups A and B and those in a third control group (Group C) were called and asked to complete a repeat CES-D via telephone interview. Logistic regression modeling was used to determine the influence of the intervention on the change in depression scores from baseline to 6 weeks. RESULTS: Ninety-eight respondents had both baseline and 6-week CES-D scores. The mean age of the respondents was 64.9 years, and women constituted 27% of the sample. There was no statistically significant clinical difference between the three groups. Regression analysis demonstrated that patients who were contacted by either telephone or mail were significantly more likely to report improvement in the CES-D scores (odds ratio = 3.03, p = .03) as compared with the control group. Furthermore, respondents who were phoned reported the highest percentage of improved CES-D scores as compared with the mailed and control groups. CONCLUSIONS: This pilot study demonstrated that early recognition strategies and referral protocols that address mental health needs are effective in decreasing the reported depressive symptomatology of this high-risk population. Proactively addressing mental health issues as an integral part of the overall treatment with patients with coronary artery disease could potentially improve the health outcomes in this population.


Assuntos
Doença da Artéria Coronariana/fisiopatologia , Depressão/complicações , Avaliação de Resultados em Cuidados de Saúde , Adulto , Alberta , Doença da Artéria Coronariana/psicologia , Feminino , Humanos , Masculino , Projetos Piloto
16.
Prog Cardiovasc Nurs ; 23(1): 27-31, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18326988

RESUMO

Increasing evidence suggests that there are sex/gender differences in the presentation and prodromal symptoms of acute coronary syndrome (ACS). The purpose of this pilot study was to identify sex differences in the prodromal symptoms of ACS using the McSweeney Acute and Prodromal Myocardial Infarction Symptom Survey (MAPMISS). Telephone surveys using the MAPMISS were conducted between 4 and 6 months after the ACS event. Seventy-six patients (24 women) participated in the study. The women generally reported higher prodromal scores. Moreover, scores demonstrated differences in prodromal symptoms based on menopausal status. The premenopausal and perimenopausal women reported a greater number and higher frequency of symptoms compared with the men and menopausal women. The results of this study suggest that both men and women report nontraditional prodromal symptoms of ACS. In addition, there appears to be a difference in the frequency and number of symptoms reported based on menopausal status.


Assuntos
Síndrome Coronariana Aguda/complicações , Síndrome Coronariana Aguda/psicologia , Atitude Frente a Saúde , Homens/psicologia , Índice de Gravidade de Doença , Mulheres/psicologia , Síndrome Coronariana Aguda/diagnóstico , Síndrome Coronariana Aguda/terapia , Idoso , Alberta , Cateterismo Cardíaco , Feminino , Humanos , Masculino , Menopausa/fisiologia , Menopausa/psicologia , Pessoa de Meia-Idade , Pesquisa Metodológica em Enfermagem , Projetos Piloto , Caracteres Sexuais , Fatores Sexuais , Inquéritos e Questionários
17.
Sci Total Environ ; 581-582: 369-377, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-28043701

RESUMO

Extraction of oil and gas from unconventional sources, such as shale, has dramatically increased over the past ten years, raising the potential for spills or releases of chemicals, waste materials, and oil and gas. We analyzed spill data associated with unconventional wells from Colorado, New Mexico, North Dakota and Pennsylvania from 2005 to 2014, where we defined unconventional wells as horizontally drilled into an unconventional formation. We identified materials spilled by state and for each material we summarized frequency, volumes and spill rates. We evaluated the environmental risk of spills by calculating distance to the nearest stream and compared these distances to existing setback regulations. Finally, we summarized relative importance to drinking water in watersheds where spills occurred. Across all four states, we identified 21,300 unconventional wells and 6622 reported spills. The number of horizontal well bores increased sharply beginning in the late 2000s; spill rates also increased for all states except PA where the rate initially increased, reached a maximum in 2009 and then decreased. Wastewater, crude oil, drilling waste, and hydraulic fracturing fluid were the materials most often spilled; spilled volumes of these materials largely ranged from 100 to 10,000L. Across all states, the average distance of spills to a stream was highest in New Mexico (1379m), followed by Colorado (747m), North Dakota (598m) and then Pennsylvania (268m), and 7.0, 13.3, and 20.4% of spills occurred within existing surface water setback regulations of 30.5, 61.0, and 91.4m, respectively. Pennsylvania spills occurred in watersheds with a higher relative importance to drinking water than the other three states. Results from this study can inform risk assessments by providing improved input parameters on volume and rates of materials spilled, and guide regulations and the management policy of spills.

18.
Epigenetics ; 6(11): 1284-94, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21937876

RESUMO

Several studies linking alterations in differential placental methylation with pregnancy disorders have implicated (de)regulation of the placental epigenome with fetal programming and later-in-life disease. We have previously demonstrated that maternal tobacco use is associated with alterations in promoter methylation of placental CYP1A1 and that these changes are correlated with CYP1A1 gene expression and fetal growth restriction. In this study we sought to expand our analysis of promoter methylation by correlating it to gene expression on a genome-wide scale. Employing side-by-side IlluminaHG-12 gene transcription with Infinium27K methylation arrays, we interrogated correlative changes in placental gene expression and DNA methylation associated with maternal tobacco smoke exposure at an epigenome-wide level and in consideration of signature gene pathways. We observed that the expression of 623 genes and the methylation of 1024 CpG dinucleotides are significantly altered among smokers, with only 38 CpGs showing significant differential methylation (differing by a methylation level of ≥10%). We identified a significant Pearson correlation (≥0.7 or ≤-0.7) between placental transcriptional regulation and differential CpG methylation in only 25 genes among non-smokers but in 438 genes among smokers (18-fold increase, p < 0.0001), with a dominant effect among oxidative stress pathways. Differential methylation at as few as 6 sites was attributed to maternal smoking-mediated birth weight reduction in linear regression models with Bonferroni correction (p < 1.8 × 10(-6)). These studies suggest that a common perinatal exposure (such as maternal smoking) deregulates placental methylation in a CpG site-specific manner that correlates with meaningful alterations in gene expression along signature pathways.


Assuntos
Metilação de DNA , DNA/metabolismo , Epigênese Genética , Genoma Humano , Exposição Materna/efeitos adversos , Placenta/metabolismo , Fumar/efeitos adversos , Adulto , Peso ao Nascer , Ilhas de CpG , Citocromo P-450 CYP1A1/genética , Citocromo P-450 CYP1A1/metabolismo , Feminino , Expressão Gênica , Idade Gestacional , Humanos , Gravidez , Efeitos Tardios da Exposição Pré-Natal/genética , Efeitos Tardios da Exposição Pré-Natal/metabolismo
19.
J Expo Sci Environ Epidemiol ; 20(1): 69-78, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19240760

RESUMO

Human exposure models often make the simplifying assumption that school children attend school in the same census tract where they live. This paper analyzes that assumption and provides information on the temporal and spatial distributions associated with school commuting. The data were obtained using Oak Ridge National Laboratory's LandScan USA population distribution model applied to Philadelphia, PA. It is a high-resolution model used to allocate individual school-aged children to both a home and school location, and to devise a minimum-time home-to-school commuting path (called a trace) between the two locations. LandScan relies heavily on Geographic Information System (GIS) data. With respect to school children attending school in their home census tract, the vast majority does not in Philadelphia. Our analyses found that: (1) about 32% of the students walk across two or more census tracts going to school and 40% of them walk across four or more census blocks; and (2) 60% drive across four or more census tracts going to school and 50% drive across 10 or more census blocks. We also find that: (3) using a 5-min commuting time interval - as opposed to the modeled "trace" - results in misclassifying the "actual" path taken in 90% of the census blocks, 70% of the block groups, and 50% of the tracts; (4) a 1-min time interval is needed to reasonably resolve time spent in the various census unit designations; and (5) approximately 50% of both the homes and schools of Philadelphia school children are located within 160 m of highly traveled roads, and 64% of the schools are located within 200 m. These findings are very important when modeling school children's exposures, especially, when ascertaining the impacts of near-roadway concentrations on their total daily body burden. As many school children also travel along these streets and roadways to get to school, a majority of children in Philadelphia are in mobile source-dominated locations most of the day. We hypothesize that exposures of school children in Philadelphia to benzene and particulate matter will be much higher than if home and school locations and commuting paths at a 1-min time resolution are not explicitly modeled in an exposure assessment. Undertaking such an assessment will be the topic of a future paper.


Assuntos
Exposição Ambiental/análise , Exposição Ambiental/estatística & dados numéricos , Sistemas de Informação Geográfica , Instituições Acadêmicas , Estudantes , Meios de Transporte/estatística & dados numéricos , Adolescente , Poluição do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Censos , Criança , Pré-Escolar , Habitação , Humanos , Philadelphia , Medição de Risco , Fatores de Tempo , Saúde da População Urbana
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