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1.
Appetite ; 196: 107258, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38341036

RESUMO

Prior studies evaluating a single meal in children characterized an "obesogenic" style of eating marked by larger bites and faster eating. It is unclear if this style is consistent across portion sizes within children so we examined eating behaviors in 91 children (7-8 years, 45 F) without obesity (BMI<90th percentile). Children consumed 4 ad libitum meals in the laboratory consisting of chicken nuggets, macaroni, grapes, and broccoli that varied in portion size (100%, 133%, 166%, 200%) with a maximum of 30 min allotted per meal. Anthropometrics were assessed using age and sex adjusted body mass index (BMI) percentile and dual energy x-ray absorptiometry. Bites, sips, active eating time, and meal duration were coded from meal videos; bite size (kcal and g/bite), proportion of active eating (active eating time/meal duration), and eating rate (kcal and g/meal duration) were computed. Intraclass correlation coefficients (ICC) showed that most eating behaviors were moderately consistent across portions (>0.50). The consistency of associations between eating behaviors and total meal intake and adiposity were assessed with general linear models adjusted for food liking, pre-meal fullness, age, and sex. Across all portions, more bites, faster eating rate, and longer meal duration were associated with greater intake. While higher BMI percentile was associated with faster eating rates across all meals, greater fat mass index was only associated with faster eating at meals with portions typical for children (i.e., 100% and 133%). In a primarily healthy weight sample, an 'obesogenic' style of eating was a consistent predictor of greater intake across meals that varied in portion size. The consistent relationship of these behaviors with intake makes them promising targets to reduce overconsumption.


Assuntos
Ingestão de Energia , Tamanho da Porção , Criança , Humanos , Comportamento Alimentar , Refeições , Obesidade , Ingestão de Alimentos
3.
J Geophys Res Space Phys ; 125(9): e2020JA027789, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33282619

RESUMO

A total solar eclipse occurred in the Southern Hemisphere on 2 July 2019 from approximately 17 to 22 UT. Its effect in the thermosphere over South America was imaged from geostationary orbit by NASA's Global-scale Observation of Limb and Disk (GOLD) instrument. GOLD observed a large brightness reduction (>80% around totality) in OI 135.6 nm and N2 LBH band emissions compared to baseline measurements made 2 days prior. In addition, a significant enhancement (with respect to the baseline) in the ΣO/N2 column density ratio (~80%) was observed within the eclipse's totality. This enhancement suggests that the eclipse induced compositional changes in the thermosphere. After the eclipse passed, a slight enhancement in ΣO/N2 column density ratio (~7%) was also seen around the totality path when compared to measurements before the eclipse. These observations are the first synoptic imaging measurements of an eclipse's thermospheric effects with the potential to drastically improve and test our understanding of how the thermosphere responds to rapid, localized changes in solar short wavelength radiation.

4.
J Gen Virol ; 99(2): 169-180, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29300155

RESUMO

Lyssavirus infection has a near 100 % case fatality rate following the onset of clinical disease, and current rabies vaccines confer protection against all reported phylogroup I lyssaviruses. However, there is little or no protection against more divergent lyssaviruses and so investigation into epitopes within the glycoprotein (G) that dictate a neutralizing response against divergent lyssaviruses is warranted. Importantly, the facilities required to work with these pathogens, including wild-type and mutated forms of different lyssaviruses, are scarcely available and, as such, this type of study is inherently difficult to perform. The relevance of proposed immunogenic antigenic sites within the lyssavirus glycoprotein was assessed by swapping sites between phylogroup-I and -II glycoproteins. Demonstrable intra- but limited inter-phylogroup cross-neutralization was observed. Pseudotype viruses (PTVs) presenting a phylogroup-I glycoprotein containing phylogroup-II antigenic sites (I, II III or IV) were neutralized by antibodies raised against phylogroup-II PTV with the site II (IIb, aa 34-42 and IIa, aa 198-200)-swapped PTVs being efficiently neutralized, whilst site IV-swapped PTV was poorly neutralized. Specific antibodies raised against PTV-containing antigenic site swaps between phylogroup-I and -II glycoproteins neutralized phylogroup-I PTVs efficiently, indicating an immunodominance of antigenic site II. Live lyssaviruses containing antigenic site-swapped glycoproteins were generated and indicated that specific residues within the lyssavirus glycoprotein dictate functionality and enable differential neutralizing antibody responses to lyssaviruses.


Assuntos
Anticorpos Antivirais/imunologia , Antígenos Virais/genética , Glicoproteínas/imunologia , Lyssavirus/imunologia , Vacina Antirrábica/imunologia , Infecções por Rhabdoviridae/prevenção & controle , Animais , Anticorpos Neutralizantes/imunologia , Antígenos Virais/imunologia , Modelos Animais de Doenças , Cães , Epitopos/genética , Epitopos/imunologia , Feminino , Glicoproteínas/genética , Humanos , Lyssavirus/genética , Camundongos , Mutação , Raiva/imunologia , Raiva/prevenção & controle , Raiva/virologia , Vírus da Raiva/genética , Vírus da Raiva/imunologia , Infecções por Rhabdoviridae/imunologia , Infecções por Rhabdoviridae/virologia
5.
Anaesth Intensive Care ; 45(1): 12-20, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-28072930

RESUMO

The current trend to treat hypotension in critically ill patients is to place a greater emphasis on inotropic support and less on fluid resuscitation in order to limit the potential harm from fluid overload. This combination may trigger left ventricular outflow tract obstruction (LVOTO) in susceptible patients. Although LVOTO is classically described in patients with hypertrophic cardiomyopathy it has been reported in other conditions including septic shock, apical ballooning syndrome, myocardial infarction, respiratory failure, and post valvular surgery. It is more common in the elderly, females, and in patients with hypertension, diabetes, and chronic vascular disease because of predisposing anatomical conditions such as left ventricular hypertrophy, small left ventricle size, sigmoid septum and alterations in the positions of the aortic and mitral valve annular planes. The onset of LVOTO is largely unpredictable due to a complex interplay between preload, afterload, heart rhythm and rate in susceptible patients. The consequences of missing this treatable condition may lead to life-threatening hypotension refractory to, or exacerbated by, a further increase in inotropic support. Dynamic LVOTO should be considered in any hypotensive intensive care patient. Echocardiography is perhaps the best tool to assess LVOTO and its underlying pathophysiology in the critically ill. Detection of LVOTO is a relatively simple task using a combination of two-dimensional, M-mode and spectral Doppler imaging by an operator alert to the possible diagnosis.


Assuntos
Hipertrofia Ventricular Esquerda , Obstrução do Fluxo Ventricular Externo , Idoso , Cardiomiopatia Hipertrófica , Ecocardiografia , Feminino , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico , Hipertrofia Ventricular Esquerda/terapia , Valva Mitral , Obstrução do Fluxo Ventricular Externo/diagnóstico , Obstrução do Fluxo Ventricular Externo/terapia
6.
Phys Chem Chem Phys ; 18(28): 19227-35, 2016 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-27367534

RESUMO

Azeotropes famously impose fundamental restrictions on distillation processes, yet their special thermodynamic properties make them highly desirable for a diverse range of industrial and technological applications. Using neutron diffraction, we investigate the structures of two prototypical azeotropes, the negative acetone-chloroform and the positive benzene-methanol azeotrope. C-HO hydrogen bonding is the dominating interaction in the negative azeotrope but C-ClO halogen bonding contributes as well. Hydrogen-bonded chains of methanol molecules, which are on average longer than in pure methanol, are the defining structural feature of the positive azeotrope illustrating the fundamentally different local mixing in the two kinds of azeotropes. The emerging trend for both azeotropes is that the more volatile components experience the more pronounced structural changes in their local environments as the azeotropes form. The mixing of the acetone-chloroform azeotrope is essentially random above 20 Å, where the running Kirkwood-Buff integrals of our structural model converge closely to the ones expected from thermodynamic data. The benzene-methanol azeotrope on the other hand displays extended methanol-rich regions and consequently the running Kirkwood-Buff integrals oscillate up to at least 60 Å. Our study provides the first experimental insights into the microstructures of azeotropes and a direct link with their thermodynamic properties. Ultimately, this will provide a route for creating tailored molecular environments in azeotropes to improve and fine-tune their performances.

7.
Science ; 350(6261): aad0313, 2015 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-26542577

RESUMO

Planetary auroras reveal the complex interplay between an atmosphere and the surrounding plasma environment. We report the discovery of low-altitude, diffuse auroras spanning much of Mars' northern hemisphere, coincident with a solar energetic particle outburst. The Imaging Ultraviolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft, detected auroral emission in virtually all nightside observations for ~5 days, spanning nearly all geographic longitudes. Emission extended down to ~60 kilometer (km) altitude (1 microbar), deeper than confirmed at any other planet. Solar energetic particles were observed up to 200 kilo--electron volts; these particles are capable of penetrating down to the 60 km altitude. Given minimal magnetic fields over most of the planet, Mars is likely to exhibit auroras more globally than Earth.

8.
Nature ; 525(7569): 367-71, 2015 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-26381985

RESUMO

Assessment of the global burden of disease is based on epidemiological cohort studies that connect premature mortality to a wide range of causes, including the long-term health impacts of ozone and fine particulate matter with a diameter smaller than 2.5 micrometres (PM2.5). It has proved difficult to quantify premature mortality related to air pollution, notably in regions where air quality is not monitored, and also because the toxicity of particles from various sources may vary. Here we use a global atmospheric chemistry model to investigate the link between premature mortality and seven emission source categories in urban and rural environments. In accord with the global burden of disease for 2010 (ref. 5), we calculate that outdoor air pollution, mostly by PM2.5, leads to 3.3 (95 per cent confidence interval 1.61-4.81) million premature deaths per year worldwide, predominantly in Asia. We primarily assume that all particles are equally toxic, but also include a sensitivity study that accounts for differential toxicity. We find that emissions from residential energy use such as heating and cooking, prevalent in India and China, have the largest impact on premature mortality globally, being even more dominant if carbonaceous particles are assumed to be most toxic. Whereas in much of the USA and in a few other countries emissions from traffic and power generation are important, in eastern USA, Europe, Russia and East Asia agricultural emissions make the largest relative contribution to PM2.5, with the estimate of overall health impact depending on assumptions regarding particle toxicity. Model projections based on a business-as-usual emission scenario indicate that the contribution of outdoor air pollution to premature mortality could double by 2050.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/efeitos adversos , Exposição Ambiental/efeitos adversos , Internacionalidade , Mortalidade Prematura , Material Particulado/efeitos adversos , Adulto , Agricultura/estatística & dados numéricos , Poluentes Atmosféricos/intoxicação , Atmosfera/química , Biomassa , Pré-Escolar , China/epidemiologia , Culinária/estatística & dados numéricos , Monitoramento Ambiental , Europa (Continente)/epidemiologia , Ásia Oriental/epidemiologia , Incêndios/estatística & dados numéricos , Calefação/estatística & dados numéricos , Humanos , Índia/epidemiologia , Lactente , Pessoa de Meia-Idade , Mortalidade Prematura/tendências , Ozônio/efeitos adversos , Ozônio/análise , Ozônio/intoxicação , Material Particulado/intoxicação , Centrais Elétricas/estatística & dados numéricos , Saúde da População Rural/estatística & dados numéricos , Federação Russa/epidemiologia , Estados Unidos/epidemiologia , Saúde da População Urbana/estatística & dados numéricos , Emissões de Veículos/intoxicação
9.
Chem Commun (Camb) ; 51(23): 4770-3, 2015 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-25562307

RESUMO

Using neutron diffraction and the isotopic substitution technique we have investigated the local structure of liquid chloroform. A strong tendency for polar stacking of molecules with collinear alignment of dipole moments is found. We speculate that these polar stacks contribute to the performance of chloroform as a solvent.

10.
Acta Biomater ; 9(2): 5341-52, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23159566

RESUMO

Titanium (Ti) and its alloys are among the most successful implantable materials for dental and orthopedic applications. The combination of excellent mechanical and corrosion resistance properties makes them highly desirable as endosseous implants that can withstand a demanding biomechanical environment. Yet, the success of the implant depends on its osteointegration, which is modulated by the biological reactions occurring at the interface of the implant. A recent development for improving biological responses on the Ti-implant surface has been the realization that bifunctional peptides can impart material binding specificity not only because of their molecular recognition of the inorganic material surface, but also through their self-assembly and ease of biological conjugation properties. To assess peptide-based functionalization on bioactivity, the present authors generated a set of peptides for implant-grade Ti, using cell surface display methods. Out of 60 unique peptides selected by this method, two of the strongest titanium binding peptides, TiBP1 and TiBP2, were further characterized for molecular structure and adsorption properties. These two peptides demonstrated unique, but similar molecular conformations different from that of a weak binder peptide, TiBP60. Adsorption measurements on a Ti surface revealed that their disassociation constants were 15-fold less than TiBP60. Their flexible and modular use in biological surface functionalization were demonstrated by conjugating them with an integrin recognizing peptide motif, RGDS. The functionalization of the Ti surface by the selected peptides significantly enhanced the bioactivity of osteoblast and fibroblast cells on implant-grade materials.


Assuntos
Implantes Experimentais , Peptídeos/farmacologia , Titânio/farmacologia , Adsorção , Sequência de Aminoácidos , Animais , Adesão Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular , Dicroísmo Circular , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Camundongos , Microscopia de Força Atômica , Dados de Sequência Molecular , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Peptídeos/química , Peptídeos/metabolismo , Ligação Proteica/efeitos dos fármacos , Propriedades de Superfície
11.
J Epidemiol Community Health ; 64(7): 630-5, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20231738

RESUMO

BACKGROUND: Contemporary warfare involving civilian populations is a growing public health concern. In addition to the psychological impact, war-related trauma may result in physiological alterations and even broader health effects. Associations were examined between war-related stressors and incident asthma in elderly Kuwaiti civilians following the Iraqi invasion. METHODS: A random sample of all Kuwaiti nationals aged 50-69 years on the day prior to the invasion were identified. Among the 7873 meeting eligibility criteria, 5567 (71%) agreed to participate and 5028 completed the questionnaire (91% of those eligible). Of these, 3759 were in Kuwait during the invasion, of whom 2294 were alive at follow-up. After exclusions for prevalent asthma or missingness on covariates, 2066 were available for analysis. War-related experiences were summarised into a continuous score using Rasch modelling. Relative Cox proportional hazard rates (HR) were calculated for asthma adjusting for covariates. RESULTS: Over 13 years of follow-up, physician-diagnosed asthma was reported by 66/996 (6.6%) men and 104/1070 (9.7%) women. In models adjusted for gender, socioeconomic status, smoking, BMI, and air pollution related to burning oil fires, those reporting highest stress exposure were more than twice as likely to report asthma (HR 2.3, 95% CI 1.3, 3.9) compared to civilians reporting no stressors. Experiences were more salient when anchored to fear for loss of life. CONCLUSIONS: War-related trauma is associated with increased asthma risk in these elderly civilians. Although prior research has documented the significant and persistent psychological toll of war, these findings implicate even broader health effects.


Assuntos
Asma/epidemiologia , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Guerra , Idoso , Feminino , Seguimentos , Humanos , Iraque/epidemiologia , Kuweit/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Modelos de Riscos Proporcionais , Fatores de Risco , Inquéritos e Questionários
13.
Heredity (Edinb) ; 98(3): 128-42, 2007 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-17080024

RESUMO

Landscape genetics has emerged as a new research area that integrates population genetics, landscape ecology and spatial statistics. Researchers in this field can combine the high resolution of genetic markers with spatial data and a variety of statistical methods to evaluate the role that landscape variables play in shaping genetic diversity and population structure. While interest in this research area is growing rapidly, our ability to fully utilize landscape data, test explicit hypotheses and truly integrate these diverse disciplines has lagged behind. Part of the current challenge in the development of the field of landscape genetics is bridging the communication and knowledge gap between these highly specific and technical disciplines. The goal of this review is to help bridge this gap by exposing geneticists to terminology, sampling methods and analysis techniques widely used in landscape ecology and spatial statistics but rarely addressed in the genetics literature. We offer a definition for the term "landscape genetics", provide an overview of the landscape genetics literature, give guidelines for appropriate sampling design and useful analysis techniques, and discuss future directions in the field. We hope, this review will stimulate increased dialog and enhance interdisciplinary collaborations advancing this exciting new field.


Assuntos
Ecossistema , Genética , Animais , Interpretação Estatística de Dados , Variação Genética , Genética Populacional , Modelos Genéticos
14.
Risk Anal ; 21(4): 625-40, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11726017

RESUMO

Extrapolation relationships are of keen interest to chemical risk assessment in which they play a prominent role in translating experimentally derived (usually in animals) toxicity estimates into estimates more relevant to human populations. A standard approach for characterizing each extrapolation relies on ratios of pre-existing toxicity estimates. Applications of this "ratio approach" have overlooked several sources of error. This article examines the case of ratios of benchmark doses, trying to better understand their informativeness. The approach involves mathematically modeling the process by which the ratios are generated in practice. Both closed form and simulation-based models of this "data-generating process" (DGP) are developed, paying special attention to the influence of experimental design. The results show the potential for significant limits to informativeness, and revealing dependencies. Future applications of the ratio approach should take imprecision and bias into account. Bootstrap techniques are recommended for gauging imprecision, but more complicated techniques will be required for gauging bias (and capturing dependencies). Strategies for mitigating the errors are suggested.


Assuntos
Modelos Teóricos , Medição de Risco/métodos , Animais , Benchmarking , Humanos , Método de Monte Carlo
15.
Risk Anal ; 21(4): 697-717, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11726021

RESUMO

Ethylene oxide is a gas produced in large quantities in the United States that is used primarily as a chemical intermediate in the production of ethylene glycol, propylene glycol, non-ionic surfactants, ethanolamines, glycol ethers, and other chemicals. It has been well established that ethylene oxide can induce cancer, genetic, reproductive and developmental, and acute health effects in animals. The U.S. Environmental Protection Agency is currently developing both a cancer potency factor and a reference concentration (RfC) for ethylene oxide. This study used the rich database on the reproductive and developmental effects of ethylene oxide to develop a probabilistic characterization of possible regulatory thresholds for ethylene oxide. This analysis was based on the standard regulatory approach for noncancer risk assessment, but involved several innovative elements, such as: (1) the use of advanced statistical methods to account for correlations in developmental outcomes among littermates and allow for simultaneous control of covariates (such as litter size); (2) the application of a probabilistic approach for characterizing the uncertainty in extrapolating the animal results to humans; and (3) the use of a quantitative approach to account for the variation in heterogeneity among the human population. This article presents several classes of results, including: (1) probabilistic characterizations of ED10s for two quantal reproductive outcomes-resorption and fetal death, (2) probabilistic characterizations of one developmental outcome-the dose expected to yield a 5% reduction in fetal (or pup) weight, (3) estimates of the RfCs that would result from using these values in the standard regulatory approach for noncancer risk assessment, and (4) a probabilistic characterization of the level of ethylene oxide exposure that would be expected to yield a 1/1,000 increase in the risk of reproductive or developmental outcomes in exposed human populations.


Assuntos
Desenvolvimento Infantil/efeitos dos fármacos , Óxido de Etileno/efeitos adversos , Reprodução/efeitos dos fármacos , Animais , Benchmarking , Pré-Escolar , Limiar Diferencial , Relação Dose-Resposta a Droga , Humanos , Probabilidade , Medição de Risco/métodos
16.
Environ Health Perspect ; 109(12): 1215-26, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11748028

RESUMO

In this paper we examine scientific evidence and related uncertainties in two steps of benefit-cost analyses of ozone reduction: estimating the health improvements attributable to reductions in ozone and determining the appropriate monetary values of these improvements. Although substantial evidence exists on molecular and physiologic impacts, the evidence needed to establish concentration-response functions is somewhat limited. Furthermore, because exposure to ozone depends on factors such as air conditioning use, past epidemiologic studies may not be directly applicable in unstudied settings. To evaluate the evidence likely to contribute significantly to benefits, we focus on four health outcomes: premature mortality, chronic asthma, respiratory hospital admissions, and minor restricted activity days. We determine concentration-response functions for these health outcomes for a hypothetical case study in Houston, Texas, using probabilistic weighting reflecting our judgment of the strength of the evidence and the possibility of confounding. We make a similar presentation for valuation, where uncertainty is due primarily to the lack of willingness-to-pay data for the population affected by ozone. We estimate that the annual monetary value of health benefits from reducing ozone concentrations in Houston is approximately $10 per person per microgram per cubic meter (24-hr average) reduced (95% confidence interval, $0.70-$40). The central estimate exceeds past estimates by approximately a factor of five, driven by the inclusion of mortality. We discuss the implications of our findings for future analyses and determine areas of research that might help reduce the uncertainties in benefit estimation.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/prevenção & controle , Custos de Cuidados de Saúde , Oxidantes Fotoquímicos/efeitos adversos , Ozônio/efeitos adversos , Saúde Pública , Atividades Cotidianas , Adolescente , Adulto , Idoso , Poluição do Ar/economia , Asma/etiologia , Asma/prevenção & controle , Criança , Pré-Escolar , Análise Custo-Benefício , Feminino , Previsões , Hospitalização/estatística & dados numéricos , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Mortalidade
17.
Value Health ; 4(5): 348-61, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11705125

RESUMO

The role of models to support recommendations on the cost-effective use of medical technologies and pharmaceuticals is controversial. At the heart of the controversy is the degree to which experimental or other empirical evidence should be required prior to model use. The controversy stems in part from a misconception that the role of models is to establish truth rather than to guide clinical and policy decisions. In other domains of public policy that involve human life and health, such as environmental protection and defense strategy, models are generally accepted as decision aids, and many models have been formally incorporated into regulatory processes and governmental decision making. We formulate an analytical framework for evaluating the role of models as aids to decision making. Implications for the implementation of Section 114 of the Food and Drug Administration Modernization Act (FDAMA) are derived from this framework.


Assuntos
Aprovação de Drogas/métodos , Farmacoeconomia , Modelos Teóricos , Formulação de Políticas , Reprodutibilidade dos Testes , Avaliação da Tecnologia Biomédica/métodos , Clorofluorcarbonetos , Ensaios Clínicos como Assunto , Análise Custo-Benefício , Tomada de Decisões , Aprovação de Equipamentos , Aprovação de Drogas/economia , Alocação de Recursos para a Atenção à Saúde , Humanos , Praguicidas , Avaliação da Tecnologia Biomédica/economia , Avaliação da Tecnologia Biomédica/normas , Estados Unidos , United States Environmental Protection Agency , United States Food and Drug Administration
18.
J Expo Anal Environ Epidemiol ; 11(4): 308-22, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11571610

RESUMO

This paper presents the results of the first phase of a study, conducted as an element of the National Human Exposure Assessment Survey (NHEXAS), to demonstrate the use of expert subjective judgment elicitation techniques to characterize the magnitude of and uncertainty in environmental exposure to benzene. In decisions about the value of exposure research or of regulatory controls, the characterization of uncertainty can play an influential role. Classical methods for characterizing uncertainty may be sufficient when adequate amounts of relevant data are available. Frequently, however, data are neither abundant nor directly relevant, making it necessary to rely to varying degrees on subjective judgment. Since the 1950s, methods to elicit and quantify subjective judgments have been explored but have rarely been applied to the field of environmental exposure assessment. In this phase of the project, seven experts in benzene exposure assessment were selected through a peer nomination process, participated in a 2-day workshop, and were interviewed individually to elicit their judgments about the distributions of residential ambient, residential indoor, and personal air benzene concentrations (6-day integrated average) experienced by both the non-smoking, non-occupationally exposed target and study populations of the US EPA Region V pilot study. Specifically, each expert was asked to characterize, in probabilistic form, the arithmetic means and the 90th percentiles of these distributions. This paper presents the experts' judgments about the concentrations of benzene encountered by the target population. The experts' judgments about levels of benzene in personal air were demonstrative of patterns observed in the judgments about the other distributions. They were in closest agreement about their predictions of the mean; with one exception, their best estimates of the mean fell within 7-11 microg/m(3) although they exhibited striking differences in the degree of uncertainty expressed. Their estimates of the 90th percentile were more varied with the best estimates ranging from 12 to 26 microg/m(3) for all but one expert. However, their predictions of the 90th percentile were far more uncertain. The paper demonstrates that coherent subjective judgments can be elicited from exposure assessment scientists and critically examines the challenges and potential benefits of a subjective judgment approach. The results of the second phase of the project, in which measurements from the NHEXAS field study in Region V are used to calibrate the experts' judgments about the benzene exposures in the study population, will be presented in a second paper.


Assuntos
Benzeno/efeitos adversos , Exposição Ambiental/análise , Poluentes Ambientais/efeitos adversos , Modelos Teóricos , Benzeno/análise , Poluentes Ambientais/análise , Previsões , Humanos , Saúde Pública , Reprodutibilidade dos Testes , Medição de Risco/métodos
19.
Q J Exp Psychol A ; 54(3): 935-58, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11548042

RESUMO

The present study extended the investigation of the belief bias effect in syllogistic reasoning in two ways: (1) The effect was studied under instructions to decide whether conclusions were possible, as well as necessary, given the premises; and (2) the effect was studied for types of syllogism where people rarely endorse the conclusions as well as those (valid and fallacious) where endorsements are common. Three experiments are reported, which show first that there is a marked tendency to reject unbelievable conclusions relative to abstract or neutral controls on all kinds of syllogism and under both types of instruction. There was also significant evidence of positive belief bias (increased acceptance of believable conclusions) and of interactions between belief bias effects and logical form. The results are discussed with particular respect to accounts of belief bias offered by theorists in the mental-model tradition.


Assuntos
Cognição , Resolução de Problemas , Humanos , Distribuição Aleatória
20.
Biochem J ; 355(Pt 3): 699-706, 2001 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-11311132

RESUMO

Phospholamban regulates the activity of the calcium-activated ATPase (CaATPase) of cardiac sarcoplasmic reticulum. Equilibrium fluorescence studies have shown that the N-terminal cytoplasmic region of phospholamban (residues 1-20, domain 1) causes a decrease in the intrinsic tryptophan fluorescence of the CaATPase. The interaction of phospholamban residues 1-20 with the CaATPase also results in spectral changes for the extrinsic chromophore FITC covalently attached to the cytoplasmic region of the calcium pump. The fluorescence changes for both reporter groups correlate with a dissociation constant of approximately 40 microM for the complex between phospholamban residues 1-20 and the CaATPase. Complex formation is notably weaker when phospholamban 1-20 is titrated into the CaATPase in the presence of calcium, with altered conformational effects resulting from binding. The interaction of domain 1 of phospholamban with the CaATPase is also reduced upon phosphorylation of phospholamban 1-20 at Ser-16. This region of phospholamban 1-20 is shown by isotope-edited NMR study to be involved in interaction with the CaATPase. Binding of the phosphorylated peptide is not abolished, however, indicating that phospholamban 1-20 remains associated with the CaATPase even after phosphorylation. The data provide direct evidence for the interaction between the cytoplasmic regions of phospholamban and the pump, and are discussed in the context of the mechanism for inhibition of cardiac CaATPase activity by phospholamban.


Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , ATPases Transportadoras de Cálcio/metabolismo , Retículo Sarcoplasmático/metabolismo , Animais , Cálcio/metabolismo , ATPases Transportadoras de Cálcio/química , Citoplasma/enzimologia , Citoplasma/metabolismo , Técnicas In Vitro , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Nucleotídeos/metabolismo , Fragmentos de Peptídeos/metabolismo , Fosforilação , Estrutura Terciária de Proteína , Coelhos , Retículo Sarcoplasmático/enzimologia
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