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1.
MMWR Morb Mortal Wkly Rep ; 69(31): 1026-1030, 2020 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-32759918

RESUMO

SARS-CoV-2, the virus that causes coronavirus disease 2019 (COVID-19), is spread from person to person (1-3). Quarantine of exposed persons (contacts) for 14 days following their exposure reduces transmission (4-7). Contact tracing provides an opportunity to identify contacts, inform them of quarantine recommendations, and monitor their symptoms to promptly identify secondary COVID-19 cases (7,8). On March 12, 2020, Maine Center for Disease Control and Prevention (Maine CDC) identified the first case of COVID-19 in the state. Because of resource constraints, including staffing, Maine CDC could not consistently monitor contacts, and automated technological solutions for monitoring contacts were explored. On May 14, 2020, Maine CDC began enrolling contacts of patients with reported COVID-19 into Sara Alert (MITRE Corporation, 2020),* an automated, web-based, symptom monitoring tool. After initial communication with Maine CDC staff members, enrolled contacts automatically received daily symptom questionnaires via their choice of e-mailed weblink, text message, texted weblink, or telephone call until completion of their quarantine. Epidemiologic investigations were conducted for enrollees who reported symptoms or received a positive SARS-CoV-2 test result. During May 14-June 26, Maine CDC enrolled 1,622 contacts of 614 COVID-19 patients; 190 (11.7%) eventually developed COVID-19, highlighting the importance of identifying, quarantining, and monitoring contacts of COVID-19 patients to limit spread. In Maine, symptom monitoring was not feasible without the use of an automated symptom monitoring tool. Using a tool that permitted enrollees to specify a method of symptom monitoring was well received, because the majority of persons monitored (96.4%) agreed to report using this system.


Assuntos
Busca de Comunicante , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/terapia , Monitoramento Epidemiológico , Pneumonia Viral/diagnóstico , Pneumonia Viral/terapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Automação , COVID-19 , Criança , Pré-Escolar , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Feminino , Humanos , Lactente , Recém-Nascido , Maine/epidemiologia , Masculino , Pessoa de Meia-Idade , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , Avaliação de Programas e Projetos de Saúde , Avaliação de Sintomas/métodos , Adulto Jovem
2.
J Public Health Manag Pract ; 25 Suppl 1, Lead Poisoning Prevention: S76-S83, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30507774

RESUMO

CONTEXT: There are limited data on the nature of environmental lead hazards identified during residential inspections for child blood lead levels (BLLs) of less than 10 µg/dL. We compare inspection findings for child BLLs of 5 to 9 µg/dL versus 10 µg/dL or more. DESIGN: We reviewed inspection reports in Maine from September 2016 to March 2018. We used continuity-adjusted or Fisher's exact test for categorical variables and Wilcoxon rank-sum tests for continuous variables to compare differences in child, family, household, and lead hazard characteristics between BLL categories (5-9 µg/dL vs ≥10 µg/dL). We used Spearman correlation coefficients to assess relationships between home surface lead dust measurements and BLLs. RESULTS: Of 351 residential inspections, 272 (77%) were for children with BLLs of 5 to 9 µg/dL. Children with BLLs of 5 to 9 µg/dL as compared with children with BLLs of 10 µg/dL or more were less likely to chew window sills and door frames (8% vs 21%; P = .01), but otherwise were similar with respect to other established risk factors for lead poisoning. Children with BLLs of 5 to 9 µg/dL tended to have fewer paint hazards inside their homes (64% vs 78%; P = .03), and they were more likely to have dust-only hazards (8% vs 3%) or no identified lead paint hazards (23% vs 15%), though these differences were not statistically significant. For children with BLLs of 5 to 9 µg/dL, BLL was weakly correlated with average window sill dust level (Spearman r = 0.16; P = .01) and average floor dust level (r = 0.13; P = .03), but these correlations were not observed for children with BLLs of 10 µg/dL and higher. CONCLUSIONS: We have found that inspections of homes of children with BLLs of 5 to 9 µg/dL are nearly as likely to identify lead hazards that require abatement as inspections of homes of children with BLLs of 10 µg/dL.


Assuntos
Chumbo/análise , Pré-Escolar , Exposição Ambiental/efeitos adversos , Feminino , Humanos , Lactente , Chumbo/sangue , Intoxicação por Chumbo/sangue , Intoxicação por Chumbo/diagnóstico , Intoxicação por Chumbo/epidemiologia , Maine/epidemiologia , Masculino , Avaliação de Programas e Projetos de Saúde/métodos , Fatores de Risco
3.
Inorg Chem ; 54(3): 837-44, 2015 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-25360864

RESUMO

The discovery of a brilliant-blue color upon the introduction of Mn(3+) to the trigonal-bipyramidal (TBP) sites in YInO(3) has led to a search for other hosts for Mn(3+) in TBP coordination. An obvious choice would be YAlO(3). This compound, which has only been prepared through a citrate precursor route, has long been considered isostructural with YInO(3). However, Mn(3+) substitutions into YAlO(3) have failed to produce a product with the anticipated color. We find that the hexagonal structure for YAlO(3) with Al in TBP coordination proposed in 1963 cannot be correct based on its unit cell dimensions and bond-valence sums. Our studies indicate instead that all, or nearly all, of the Al in this compound has a coordination number (CN) of 6. Upon heating in air, this compound transforms to YAlO(3), with the perovskite structure liberating CO(2). The compound long assumed to be a hexagonal form of YAlO(3) is actually an oxycarbonate with the ideal composition Y(3)Al(3)O(8)CO(3). The structure of this compound has been characterized by powder neutron and X-ray diffraction data obtained as a function of temperature, magic-angle-spinning (27)Al NMR, Fourier transform infrared, and transmission electron microscopy. Refinement of neutron diffraction data indicates a composition of Y(3)Al(3)O(8)CO(3). We find that the hexagonal structures of YGaO(3) and YFeO(3) from the citrate route are also stabilized by small amounts of carbonate. Surprisingly, Y(3)Al(3)O(8)CO(3) forms a complete solid solution with YBO(3) having tetrahedral borate groups. Other unlikely solid solutions were prepared in the YAlO(3)-YMnO(3), YAlO(3)-YFeO(3), YAlO(3)-YBO(3), YBO(3)-YMnO(3), YBO(3)-YFeO(3), and YBO(3)-YGaO(3) systems.

4.
Environ Sci Technol ; 48(8): 4298-306, 2014 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-24655434

RESUMO

In greater Augusta of central Maine, 53 out of 1093 (4.8%) private bedrock well water samples from 1534 km(2) contained [U] >30 µg/L, the U.S. Environmental Protection Agency's (EPA) Maximum Contaminant Level (MCL) for drinking water; and 226 out of 786 (29%) samples from 1135 km(2) showed [Rn] >4,000 pCi/L (148 Bq/L), the U.S. EPA's Alternative MCL. Groundwater pH, calcite dissolution and redox condition are factors controlling the distribution of groundwater U but not Rn due to their divergent chemical and hydrological properties. Groundwater U is associated with incompatible elements (S, As, Mo, F, and Cs) in water samples within granitic intrusions. Elevated [U] and [Rn] are located within 5-10 km distance of granitic intrusions but do not show correlations with metamorphism at intermediate scales (10(0)-10(1) km). This spatial association is confirmed by a high-density sampling (n = 331, 5-40 samples per km(2)) at local scales (≤10(-1) km) and the statewide sampling (n = 5857, 1 sample per 16 km(2)) at regional scales (10(2)-10(3) km). Wells located within 5 km of granitic intrusions are at risk of containing high levels of [U] and [Rn]. Approximately 48 800-63 900 and 324 000 people in Maine are estimated at risk of exposure to U (>30 µg/L) and Rn (>4000 pCi/L) in well water, respectively.


Assuntos
Sedimentos Geológicos/química , Radônio/análise , Urânio/análise , Poluentes Radioativos da Água/análise , Poços de Água/química , Água Potável/química , Geografia , Maine , Medição de Risco , Estados Unidos
5.
Phys Rev Lett ; 111(4): 046102, 2013 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-23931385

RESUMO

Atomic-scale imaging and first-principles modeling are applied to the heterophase interface between the Al-Cu solid solution (αCu) and θ' (Al2Cu) phases. Contrary to recent studies, our observations reveal a diffuse interface of complex but well-defined structure that enables the progression from αCu to θ' over a distance of ≈1 nm. We demonstrate that, surprisingly, the observed interfacial structure is not preferred on energetic grounds. Rather, the excess in interfacial energy is compensated by efficient atomic-scale kinetics of the αCu→θ' phase transformation.

6.
Environ Res ; 126: 232-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24074700

RESUMO

Humans exposed to methylmercury (MeHg) can suffer from adverse health impacts, e.g., serious neurological damage; however, fish is also a good source of omega-3 fish oils which promotes infants' neurological development. Because eating fish is the primary mechanism of MeHg exposure, federal and state agencies issue fish consumption advisories to inform the public about the risks of eating contaminated fish. An advisory's purpose is to provide information to consumers to increase their knowledge of specific product attributes; however, the difficulty in communicating both the risks and benefits of eating fish leads readers of fish advisories to over-restrict their fish consumption. Because the effectiveness of fish consumption advisories are not often evaluated by states, we help fill this gap by evaluating the effectiveness of Maine's fish consumption advisory in terms of improving knowledge. The results suggest the advisory successfully increased women's knowledge of both the benefits and risks of consuming fish while pregnant. The advisory also increased their ability to differentiate fish by their MeHg content, knowledge of both low and high-MeHg fish and knowledge of detailed attributes of seemingly substitutable goods, such as white tuna, light tuna and pre-packaged salmon. People who did not read the advisory lack the knowledge of how to identify fish that provide: health benefits like Omega-3 fatty acids, or health risks like MeHg; reading the advisory reduces this lack of knowledge. Readers increased ability to make specific substitutions to minimize risk while maintaining the benefits of fish eating suggests the advisory has the potential of reducing MeHg-related health risks while avoiding the drop in fish consumption show in other studies.


Assuntos
Ácidos Graxos Ômega-3 , Conhecimentos, Atitudes e Prática em Saúde , Compostos de Metilmercúrio , Alimentos Marinhos , Feminino , Educação em Saúde , Humanos , Gravidez , Análise de Regressão , Medição de Risco
7.
Sci Total Environ ; 738: 139683, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32535281

RESUMO

Over 2 million mostly rural Americans are at risk of drinking water from private wells that contain arsenic (As) exceeding the U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Level (MCL) of 10 micrograms per liter (µg/L). How well existing treatment technologies perform in real world situations, and to what extent they reduce health risks, are not well understood. This study evaluates the effectiveness of household As treatment systems in southern-central Maine (ME, n = 156) and northern New Jersey (NJ, n = 94) and ascertains how untreated well water chemistry and other factors influence As removal. Untreated and treated water samples, as well as a treatment questionnaire, were collected. Most ME households had point-of-use reverse-osmosis systems (POU RO), while in NJ, dual-tank point-of-entry (POE) whole house systems were popular. Arsenic treatment systems reduced well water arsenic concentrations ([As]) by up to two orders of magnitude, i.e. from a median of 71.7 to 0.8 µg/L and from a mean of 105 to 14.3 µg/L in ME, and from a median of 8.6 to 0.2 µg/L and a mean of 15.8 to 2.1 µg/L in NJ. More than half (53%) of the systems in ME reduced water [As] to below 1 µg/L, compared to 69% in NJ. The treatment system failure rates were 19% in ME (>USEPA MCL of 10 µg/L) and 16% in NJ (>NJ MCL of 5 µg/L). In both states, the higher the untreated well water [As] and the As(III)/As ratio, the higher the rate of treatment failure. POE systems failed less than POU systems, as did the treatment systems installed and maintained by vendors than those by homeowners. The 7-fold reduction of [As] in the treated water reduced skin cancer risk alone from 3765 to 514 in 1 million in ME, and from 568 to 75 in 1 million in NJ.


Assuntos
Arsênio/análise , Água Potável , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Maine , New Jersey , Estados Unidos , Abastecimento de Água , Poços de Água
8.
J Am Chem Soc ; 131(47): 17084-6, 2009 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-19899792

RESUMO

We show that trivalent manganese, Mn(3+), imparts an intense blue color to oxides when it is introduced at dilution in trigonal bipyramidal coordination. Our optical measurements and first-principles density functional theory calculations indicate that the blue color results from an intense absorption in the red/green region. This absorption is due in turn to a symmetry-allowed optical transition between the valence-band maximum, composed of Mn 3d(x(2)-y(2),xy) states strongly hybridized with O 2p(x,y) states, and the narrow Mn 3d(z(2))-based conduction-band minimum. We begin by demonstrating and explaining the effect using a well-defined prototype system: the hexagonal YMnO(3)-YInO(3) solid solution. We then show that the behavior is a general feature of diluted Mn(3+) in this coordination environment.

9.
Public Health Rep ; 122(2): 145-54, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17357356

RESUMO

OBJECTIVES: The purpose of this study was to describe results from a pilot surveillance system for carbon monoxide poisoning--a significant yet preventable public health issue for which most public health agencies do not conduct routine public health surveillance. METHODS: The authors developed a rate-based statewide surveillance system. Cases were identified using the 1998 Council of State and Territorial Epidemiologists' case definition in hospital discharges, emergency department and hospital outpatient visits, and mortality data. Intentional and fire-related injuries were excluded. The system was supplemented with qualitative information from newspaper articles. Annual, age, and sex-specific incidence rates were estimated. Exposure source/setting was described using E-codes; occupational setting was assessed by combining E-codes and payer code. Cases occurring during a disaster-related power outage in January 1998 were compared with cases identified during routine surveillance from 1999 through 2003. RESULTS: During the five years of routine surveillance, 740 cases were identified; 47 (6.4%) were hospitalized, 442 (59.7%) were seen in an emergency department, and 251 (34.3%) were seen in another outpatient setting. More cases were observed in fall/winter; 23.1% of patients aged 16 or older were classified as exposed in an occupational setting. Among disaster-related cases, more were older (> or =65 years of age; 11.9% vs. 4.2%) and female (61.6% vs. 45.3%); and fewer were in occupational settings (1.8% vs. 23.1%). CONCLUSIONS: Establishing state-based public health surveillance for CO poisoning is feasible and essential for guiding prevention and control efforts. The finding that more than 20% of cases were classified as occupational should be investigated further.


Assuntos
Intoxicação por Monóxido de Carbono/epidemiologia , Exposição Ambiental/efeitos adversos , Vigilância da População , Administração em Saúde Pública , Informática em Saúde Pública , Governo Estadual , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Intoxicação por Monóxido de Carbono/prevenção & controle , Criança , Pré-Escolar , Estudos de Viabilidade , Feminino , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Maine/epidemiologia , Masculino , Pessoa de Meia-Idade , Desenvolvimento de Programas , Avaliação de Programas e Projetos de Saúde
10.
Sci Total Environ ; 544: 701-10, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26674699

RESUMO

There is little published literature on the efficacy of strategies to reduce exposure to residential well water arsenic. The objectives of our study were to: 1) determine if water arsenic remained a significant exposure source in households using bottled water or point-of-use treatment systems; and 2) evaluate the major sources and routes of any remaining arsenic exposure. We conducted a cross-sectional study of 167 households in Maine using one of these two strategies to prevent exposure to arsenic. Most households included one adult and at least one child. Untreated well water arsenic concentrations ranged from <10 µg/L to 640 µg/L. Urine samples, water samples, daily diet and bathing diaries, and household dietary and water use habit surveys were collected. Generalized estimating equations were used to model the relationship between urinary arsenic and untreated well water arsenic concentration, while accounting for documented consumption of untreated water and dietary sources. If mitigation strategies were fully effective, there should be no relationship between urinary arsenic and well water arsenic. To the contrary, we found that untreated arsenic water concentration remained a significant (p ≤ 0.001) predictor of urinary arsenic levels. When untreated water arsenic concentrations were <40 µg/L, untreated water arsenic was no longer a significant predictor of urinary arsenic. Time spent bathing (alone or in combination with water arsenic concentration) was not associated with urinary arsenic. A predictive analysis of the average study participant suggested that when untreated water arsenic ranged from 100 to 500 µg/L, elimination of any untreated water use would result in an 8%-32% reduction in urinary arsenic for young children, and a 14%-59% reduction for adults. These results demonstrate the importance of complying with a point-of-use or bottled water exposure reduction strategy. However, there remained unexplained, water-related routes of exposure.


Assuntos
Arsênio/análise , Água Potável/química , Exposição Ambiental/estatística & dados numéricos , Poluentes Químicos da Água/análise , Poços de Água , Monitoramento Ambiental , Características da Família , Humanos , Maine , Purificação da Água
11.
Sci Total Environ ; 562: 1019-1030, 2016 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-27118035

RESUMO

Arsenic is a naturally occurring toxic element often concentrated in groundwater at levels unsafe for human consumption. Private well water in the United States is mostly unregulated by federal and state drinking water standards. It is the responsibility of the over 13 million U.S. households regularly depending on private wells for their water to ensure it is safe for drinking. There is a consistent graded association with health outcomes at all levels of socioeconomic status (SES) in the U.S. Differential exposure to environmental risk may be contributing to this persistent SES-health gradient. Environmental justice advocates cite overwhelming evidence that income and other SES measures are consistently inversely correlated with exposure to suboptimal environmental conditions including pollutants, toxins, and their impacts. Here we use private well household surveys from two states to investigate the association between SES and risks for arsenic exposure, examining the potentially cumulative effects of residential location, testing and treatment behavior, and psychological factors influencing behavior. We find that the distribution of natural arsenic hazard in the environment is socioeconomically random. There is no evidence that higher SES households are avoiding areas with arsenic or that lower SES groups are disproportionately residing in areas with arsenic. Instead, disparities in exposure arise from differing rates of protective action, primarily testing well water for arsenic, and secondly treating or avoiding contaminated water. We observe these SES disparities in behavior as well as in the psychological factors that are most favorable to these behaviors. Assessment of risk should not be limited to the spatial occurrence of arsenic alone. It is important that social vulnerability factors are incorporated into risk modeling and identifying priority areas for intervention, which should include strategies that specifically target socioeconomically vulnerable groups as well as all the conditions which cause these disparities in testing and treatment behavior.


Assuntos
Arsênio/análise , Exposição Ambiental/estatística & dados numéricos , Classe Social , Poluentes Químicos da Água/análise , Poluição da Água/estatística & dados numéricos , Água Subterrânea/química , Humanos , Maine , New Jersey , Medição de Risco , Inquéritos e Questionários , Poços de Água
12.
Environ Health Perspect ; 111(12): 1465-70, 2003 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-12948885

RESUMO

In the current U.S. Environmental Protection Agency reference dose (RfD) for methylmercury, the one-compartment pharmacokinetic model is used to convert fetal cord blood mercury (Hg) concentration to a maternal intake dose. This requires a ratio relating cord blood Hg concentration to maternal blood Hg concentration. No formal analysis of either the central tendency or variability of this ratio has been done. This variability contributes to the overall variability in the dose estimate. A ratio of 1.0 is implicitly used in the model, but an uncertainty factor adjustment is applied to the central tendency estimate of dose to address variability in that estimate. Thus, incorporation of the cord:maternal ratio and its variability into the estimate of intake dose could result in a significant change in the value of the RfD. We analyzed studies providing data on the cord:maternal blood Hg ratio and conducted a Monte Carlo-based meta-analysis of 10 studies meeting all inclusion criteria to generate a comprehensive estimate of the central tendency and variability of the ratio. This analysis results in a recommended central tendency estimate of 1.7, a coefficient of variation of 0.56, and a 95th percentile of 3.4. By analogy to the impact of the similar hair:blood Hg ratio on the overall variability in the dose estimate, incorporation of the cord:maternal ratio may support a 3-fold uncertainty factor adjustment to the central tendency estimate of dose to account for pharmacokinetic variability. Whether the information generated in this analysis is sufficient to warrant a revision to the RfD will depend on the outcome of a comprehensive reanalysis of the entire one-compartment model. We are currently engaged in such an analysis.


Assuntos
Poluentes Ambientais/farmacocinética , Sangue Fetal/química , Troca Materno-Fetal , Compostos de Metilmercúrio/farmacocinética , Adulto , Feminino , Humanos , Recém-Nascido , Método de Monte Carlo , Gravidez , Valores de Referência , Reprodutibilidade dos Testes , Medição de Risco
14.
Science ; 331(6024): 1583-6, 2011 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-21436448

RESUMO

Aluminum is considered to approach an "ideal" metal or free electron gas. The valence electrons move freely, as if unaffected by the presence of the metal ions. Therefore, the electron redistribution due to chemical bonding is subtle and has proven extremely difficult to determine. Experimental measurements and ab initio calculations have yielded substantially different results. We applied quantitative convergent-beam electron diffraction to aluminum to provide an experimental determination of the bonding electron distribution. Calculation of the electron distribution based on density functional theory is shown to be in close agreement. Our results yield an accurate quantitative correlation between the anisotropic elastic properties of aluminum and the bonding electron and electrostatic potential distributions.

15.
Sci Total Environ ; 409(18): 3257-66, 2011 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-21663945

RESUMO

Eating fish provides health benefits; however, nearly all fish contain at least some methylmercury which can impair human health. While government agencies have been issuing fish consumption advisories for 40 years, recent evaluation efforts highlight their poor performance. The benefit of an advisory can be measured by its ability to inform consumers as to both the positive and negative attributes of their potential choices, leading to appropriate changes in behavior. Because of the health benefits, fish advisories should not reduce fish consumption, even among at-risk individuals, but should lead consumers to switch away from highly contaminated fish toward those less contaminated. Although studies document how advisories reduce fish consumption (a negative outcome), no study indicates whether they lead to switching behavior (a positive outcome). We explore the effects of Maine Center of Disease Control and Prevention's advisory aimed at informing women who may become pregnant, nursing mothers and pregnant women about the benefits and risks of fish consumption. We examine how the advisory changes consumption, especially related to switching behavior. We demonstrate such changes in behavior both during and after pregnancy and compare the advisory-induced changes with those induced by other information sources. Although we find the advisory reduced some women's consumption of fish, we find the decrease is short-lived. Most importantly, the advisory induced appropriate switching behavior; women reading the advisory decreased their consumption of high-risk fish and increased their consumption of low-risk fish. We conclude a well-designed advisory can successfully transform a complex risk/benefit message into one that leads to appropriate knowledge and behavioral changes.


Assuntos
Comunicação em Saúde/métodos , Exposição Materna/prevenção & controle , Alimentos Marinhos/estatística & dados numéricos , Adulto , Dieta/estatística & dados numéricos , Feminino , Contaminação de Alimentos/estatística & dados numéricos , Doenças Transmitidas por Alimentos/prevenção & controle , Redução do Dano , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Disseminação de Informação/métodos , Exposição Materna/estatística & dados numéricos , Compostos de Metilmercúrio/toxicidade , Gravidez
16.
J Expo Sci Environ Epidemiol ; 20(7): 634-43, 2010 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-20664650

RESUMO

Blood lead concentrations are higher in young children than in other age groups, whereas little is known regarding concentrations of other metals in young children. We measured the concentrations of a suite of metals in the blood of children 1-6 years of age, and assessed potential differences by age, season, or region of Maine. We used blood submitted to the Maine State Health and Environmental Testing Laboratory for blood lead analysis to determine the concentrations of arsenic (As), antimony (Sb), cadmium (Cd), manganese (Mn), mercury (Hg), selenium (Se), tin (Sn), and uranium (U) in 1350 children 1-6 years of age. The essential metals Mn and Se were detected in all samples, and As and Sb were detected in >90% of samples. Hg was detected in approximately 60% of samples. U and Cd were less often detected in blood samples, at approximately 30% and 10% of samples, respectively. Sn was not detected in any sample. Concentrations of As, Hg, and Se increased with age, whereas Sb decreased with age. Concentrations also varied by season and region for some though not all metals. Significant pairwise correlations were observed for a number of metals. Blood is a reasonable compartment for measurement of most of these metals in young children. The use of convenience samples provided a cost-effective mechanism for assessing exposure of young children in Maine.


Assuntos
Metais/sangue , Fatores Etários , Antimônio/sangue , Arsênio/sangue , Cádmio/sangue , Criança , Pré-Escolar , Exposição Ambiental/estatística & dados numéricos , Feminino , Humanos , Lactente , Chumbo/sangue , Maine , Masculino , Manganês/sangue , Mercúrio/sangue , Estações do Ano , Selênio/sangue , Estanho/sangue , Urânio/sangue
17.
Behav Res Methods ; 38(2): 262-79, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16956103

RESUMO

The Leximancer system is a relatively new method for transforming lexical co-occurrence information from natural language into semantic patterns in a nunsupervised manner. It employs two stages of co-occurrence information extraction-semantic and relational-using a different algorithm for each stage. The algorithms used are statistical, but they employ nonlinear dynamics and machine learning. This article is an attempt to validate the output of Leximancer, using a set of evaluation criteria taken from content analysis that are appropriate for knowledge discovery tasks.


Assuntos
Idioma , Linguística/instrumentação , Semântica , Desenho de Equipamento , Humanos
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