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1.
BMC Public Health ; 24(1): 796, 2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38481164

RESUMO

BACKGROUND: Migration-related changes in dietary patterns and other structural and individual factors affect weight-related health practices of individuals migrating from low-and-middle-income to high-income countries. Thus, individuals of ethnically diverse backgrounds may be disproportionately affected by poorer health outcomes, including weight-related health issues. Understanding how this community could be supported to adopt weight-related healthy practices such as optimum dietary and exercise behaviour is an important issue for public health research. Against this backdrop, we explored structural and individual factors that facilitate and constrain the uptake of weight management services among members of minority ethnic communities in Medway, England. METHODS: Data were collected from audio-recorded interviews with 12 adult community members from minoritised ethnic communities using a semi-structured interview guide. Participants were recruited through a purposive and convenient sampling technique. Generated data were transcribed, coded into NVivo and analysed using the reflexive thematic analytical technique. RESULTS: Results showed that social support and health benefits of weight management were the main motivating factors for weight management among the study participants. Conversely, systemic barriers, family commitment and caring responsibilities, changes in dietary patterns post-migration and cultural norms were major factors constraining participants from adopting weight management behaviours. CONCLUSION: The results of this study indicate that structural and person-level factors serve as both facilitators and barriers to weight management among ethnically diverse communities in Medway, England. While our study is exploratory and opens doors for more studies among the population, we conclude that these minoritised communities could benefit from more equitable, tailored weight management programmes to support them in adopting weight-related practices.


Assuntos
Longevidade , Motivação , Adulto , Humanos , Inglaterra , Comportamentos Relacionados com a Saúde , Pesquisa Qualitativa
2.
Artigo em Inglês | MEDLINE | ID: mdl-38387881

RESUMO

PURPOSE: Despite educational mandates to assess resident teaching competence, limited instruments with validity evidence exist for this purpose. Existing instruments do not allow faculty to assess resident-led teaching in a large group format or whether teaching was interactive. This study gathers validity evidence on the use of the Resident-led Large Group Teaching Assessment Instrument (Relate), an instrument used by faculty to assess resident teaching competency. Relate comprises 23 behaviors divided into six elements: learning environment, goals and objectives, content of talk, promotion of understanding and retention, session management, and closure. METHODS: Messick's unified validity framework was used for this study. Investigators used video recordings of resident-led teaching from three pediatric residency programs to develop Relate and a rater guidebook. Faculty were trained on instrument use through frame-of-reference training. Resident teaching at all sites was video-recorded during 2018-2019. Two trained faculty raters assessed each video. Descriptive statistics on performance were obtained. Validity evidence sources include: rater training effect (response process), reliability and variability (internal structure), and impact on Milestones assessment (relations to other variables). RESULTS: Forty-eight videos, from 16 residents, were analyzed. Rater training improved inter-rater reliability from 0.04 to 0.64. The Φ-coefficient reliability was 0.50. There was a significant correlation between overall Relate performance and the pediatric teaching Milestone, r = 0.34, P = .019. CONCLUSION: Relate provides validity evidence with sufficient reliability to measure resident-led large-group teaching competence.


Assuntos
Internato e Residência , Humanos , Estados Unidos , Criança , Reprodutibilidade dos Testes , Competência Clínica , Avaliação Educacional , Docentes
3.
Langmuir ; 39(15): 5505-5513, 2023 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-37027519

RESUMO

The chemistry and structure of the air-ocean interface modulate biogeochemical processes between the ocean and atmosphere and therefore impact sea spray aerosol properties, cloud and ice nucleation, and climate. Protein macromolecules are enriched in the sea surface microlayer and have complex adsorption properties due to the unique molecular balance of hydrophobicity and hydrophilicity. Additionally, interfacial adsorption properties of proteins are of interest as important inputs for ocean climate modeling. Bovine serum albumin is used here as a model protein to investigate the dynamic surface behavior of proteins under several variable conditions including solution ionic strength, temperature, and the presence of a stearic acid (C17COOH) monolayer at the air-water interface. Key vibrational modes of bovine serum albumin are examined via infrared reflectance-absorbance spectroscopy, a specular reflection method that ratios out the solution phase and highlights the aqueous surface to determine, at a molecular level, the surface structural changes and factors affecting adsorption to the solution surface. Amide band reflection absorption intensities reveal the extent of protein adsorption under each set of conditions. Studies reveal the nuanced behavior of protein adsorption impacted by ocean-relevant sodium concentrations. Moreover, protein adsorption is most strongly affected by the synergistic effects of divalent cations and increased temperature.


Assuntos
Soroalbumina Bovina , Água , Soroalbumina Bovina/química , Água/química , Adsorção , Temperatura , Cátions , Propriedades de Superfície
4.
PLoS One ; 18(3): e0283447, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36952555

RESUMO

Throughout the COVID-19 pandemic, valuable datasets have been collected on the effects of the virus SARS-CoV-2. In this study, we combined whole genome sequencing data with clinical data (including clinical outcomes, demographics, comorbidity, treatment information) for 929 patient cases seen at a large UK hospital Trust between March 2020 and May 2021. We identified associations between acute physiological status and three measures of disease severity; admission to the intensive care unit (ICU), requirement for intubation, and mortality. Whilst the maximum National Early Warning Score (NEWS2) was moderately associated with severe COVID-19 (A = 0.48), the admission NEWS2 was only weakly associated (A = 0.17), suggesting it is ineffective as an early predictor of severity. Patient outcome was weakly associated with myriad factors linked to acute physiological status and human genetics, including age, sex and pre-existing conditions. Overall, we found no significant links between viral genomics and severe outcomes, but saw evidence that variant subtype may impact relative risk for certain sub-populations. Specific mutations of SARS-CoV-2 appear to have little impact on overall severity risk in these data, suggesting that emerging SARS-CoV-2 variants do not result in more severe patient outcomes. However, our results show that determining a causal relationship between mutations and severe COVID-19 in the viral genome is challenging. Whilst improved understanding of the evolution of SARS-CoV-2 has been achieved through genomics, few studies on how these evolutionary changes impact on clinical outcomes have been seen due to complexities associated with data linkage. By combining viral genomics with patient records in a large acute UK hospital, this study represents a significant resource for understanding risk factors associated with COVID-19 severity. However, further understanding will likely arise from studies of the role of host genetics on disease progression.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , SARS-CoV-2/genética , Pandemias , Medicina Estatal , Confiança , Unidades de Terapia Intensiva , Fatores de Risco , Hospitais , Intubação Intratraqueal , Reino Unido/epidemiologia
6.
Front Cell Infect Microbiol ; 12: 1066390, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36741977

RESUMO

Introduction: Throughout the global COVID-19 pandemic, nosocomial transmission has represented a major concern for healthcare settings and has accounted for many infections diagnosed within hospitals. As restrictions ease and novel variants continue to spread, it is important to uncover the specific pathways by which nosocomial outbreaks occur to understand the most suitable transmission control strategies for the future. Methods: In this investigation, SARS-CoV-2 genome sequences obtained from 694 healthcare workers and 1,181 patients were analyzed at a large acute NHS hospital in the UK between September 2020 and May 2021. These viral genomic data were combined with epidemiological data to uncover transmission routes within the hospital. We also investigated the effects of the introduction of the highly transmissible variant of concern (VOC), Alpha, over this period, as well as the effects of the national vaccination program on SARS-CoV-2 infection in the hospital. Results: Our results show that infections of all variants within the hospital increased as community prevalence of Alpha increased, resulting in several outbreaks and super-spreader events. Nosocomial infections were enriched amongst older and more vulnerable patients more likely to be in hospital for longer periods but had no impact on disease severity. Infections appeared to be transmitted most regularly from patient to patient and from patients to HCWs. In contrast, infections from HCWs to patients appeared rare, highlighting the benefits of PPE in infection control. The introduction of the vaccine at this time also reduced infections amongst HCWs by over four-times. Discussion: These analyses have highlighted the importance of control measures such as regular testing, rapid lateral flow testing alongside polymerase chain reaction (PCR) testing, isolation of positive patients in the emergency department (where possible), and physical distancing of patient beds on hospital wards to minimize nosocomial transmission of infectious diseases such as COVID-19.


Assuntos
COVID-19 , Infecção Hospitalar , Humanos , COVID-19/epidemiologia , SARS-CoV-2/genética , Infecção Hospitalar/epidemiologia , Pandemias/prevenção & controle , Genômica , Reino Unido/epidemiologia
7.
BMJ Open Respir Res ; 8(1)2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33414260

RESUMO

INTRODUCTION: The prognosis of malignant pleural mesothelioma (MPM) is poor, with a median survival of 8-12 months. The ability to predict prognosis in MPM would help clinicians to make informed decisions regarding treatment and identify appropriate research opportunities for patients. The aims of this study were to examine associations between clinical and pathological information gathered during routine care, and prognosis of patients with MPM, and to develop a 6-month mortality risk prediction model. METHODS: A retrospective cohort study of patients diagnosed with MPM at Queen Alexandra Hospital, Portsmouth, UK between December 2009 and September 2013. Multivariate analysis was performed on routinely available histological, clinical and laboratory data to assess the association between different factors and 6-month survival, with significant associations used to create a model to predict the risk of death within 6 months of diagnosis with MPM. RESULTS: 100 patients were included in the analysis. Variables significantly associated with patient survival in multivariate analysis were age (HR 1.31, 95% CI 1.09 to 1.56), smoking status (current smoker HR 3.42, 95% CI 1.11 to 4.20), chest pain (HR 2.14, 95% CI 1.23 to 3.72), weight loss (HR 2.13, 95% CI 1.18 to 3.72), platelet count (HR 1.05, 95% CI 1.00 to 1.10), urea (HR 2.73, 95% CI 1.31 to 5.69) and adjusted calcium (HR 1.47, 95% CI 1.10 to 1.94). The resulting risk model had a c-statistic value of 0.76. A Hosmer-Lemeshow test confirmed good calibration of the model against the original dataset. CONCLUSION: Risk of death at 6 months in patients with a confirmed diagnosis of MPM can be predicted using variables readily available in clinical practice. The risk prediction model we have developed may be used to influence treatment decisions in patients with MPM. Further validation of the model requires evaluation of its performance on a separate dataset.


Assuntos
Neoplasias Pulmonares , Mesotelioma Maligno , Mesotelioma , Neoplasias Pleurais , Humanos , Laboratórios , Neoplasias Pulmonares/diagnóstico , Mesotelioma/diagnóstico , Neoplasias Pleurais/diagnóstico , Estudos Retrospectivos
8.
Eur Respir J ; 52(6)2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30361247

RESUMO

Previous publications have highlighted the disparity between research trial populations and those in clinical practice, but it has not been established how this relates to randomised controlled trials (RCTs) of phenotype-targeted biological therapies in severe asthma.Detailed characterisation data for 342 severe asthma patients within the Wessex Severe Asthma Cohort (WSAC) was compared against comprehensive trial eligibility criteria for published phase IIB and phase III RCTs evaluating biological therapies in severe asthma since 2000.37 RCTs evaluating 20 biological therapies were identified. Only a median of 9.8% (range 3.5-17.5%) of severe asthma patients were found to be eligible for enrolment in the phase III trials. Stipulations for airflow obstruction, bronchodilator reversibility and smoking history excluded significant numbers of patients. A median of 78.9% (range 73.2-86.6%) of patients with severe eosinophilic asthma would have been excluded from participation in the phase III licensing trials of interleukin (IL)-5/IL-5R targeted therapies.Despite including only well characterised and optimally treated severe asthmatics under specialist care within the WSAC study, the vast majority were excluded from trial participation by criteria designed to re-confirm diagnostic labels rather than by biomarker criteria that predict the characteristic addressed by the treatment.


Assuntos
Asma/terapia , Seleção de Pacientes , Fenótipo , Ensaios Clínicos Controlados Aleatórios como Assunto/estatística & dados numéricos , Adulto , Antiasmáticos/uso terapêutico , Asma/fisiopatologia , Terapia Biológica , Biomarcadores , Broncodilatadores/uso terapêutico , Ensaios Clínicos Fase II como Assunto , Ensaios Clínicos Fase III como Assunto , Estudos Transversais , Progressão da Doença , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
9.
Clin Respir J ; 12(1): 200-206, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27330031

RESUMO

INTRODUCTION: Asthma is a prevalent, chronic disease associated with significant risk to patients and cost to healthcare systems. Accurate estimates of length of stay and recovery are important for patient information, physician prognostication, and management of inpatient beds. OBJECTIVES: To assess factors affecting length of stay and time to recovery in adults with acute asthma. METHODS: We prospectively recruited adult asthmatic non-smokers admitted with an asthma exacerbation. Participants were assessed for demographics, symptoms, medications, bloods including blood count, clotting status, and cytokines. Results were analyzed for correlation and subsequently in a regression model. RESULTS: One hundred twenty-six participants were recruited of which 75.4% were female. Mean age was 40.0 and mean length of stay was 3.98 days. Length of stay was associated with lower APTT ratio (

1 pg/mL (P = 0.04). CONCLUSION: Older participants with lower FEV1 and supplemental oxygen requirements are likely to remain in hospital longer. Activation of the "intrinsic" clotting pathway correlates with an increased length of stay as does a raised serum AST. Detectable IL-12 in plasma correlates with slower recovery and this may be due to poor response to corticosteroids.


Assuntos
Asma/fisiopatologia , Citocinas/sangue , Fluxo Expiratório Forçado/fisiologia , Tempo de Internação/tendências , Pulmão/fisiopatologia , Oxigenoterapia/métodos , Recuperação de Função Fisiológica , Doença Aguda , Adolescente , Adulto , Idoso , Asma/sangue , Asma/terapia , Biomarcadores/sangue , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Adulto Jovem
10.
Laterality ; 23(4): 391-408, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28803507

RESUMO

The assessment of active language lateralization in infants and toddlers is challenging. It requires an imaging tool that is unintimidating, quick to setup, and robust to movement, in addition to an engaging and cognitively simple language processing task. Functional Transcranial Doppler Ultrasound (fTCD) offers a suitable technique and here we report on a suitable method to elicit active language production in young children. The 34-second "What Box" trial presents an animated face "searching" for an object. The face "finds" a box that opens to reveal a to-be-labelled object. In a sample of 95 children (1 to 5 years of age), 81% completed the task-32% with ≥10 trials. The task was validated (ρ = 0.4) against the gold standard Word Generation task in a group of older adults (n = 65, 60-85 years of age), though was less likely to categorize lateralization as left or right, indicative of greater measurement variability. Existing methods for active language production have been used with 2-year-old children while passive listening has been conducted with sleeping 6-month-olds. This is the first active method to be successfully employed with infants through to pre-schoolers, forming a useful tool for populations in which complex instructions are problematic.


Assuntos
Encéfalo/fisiologia , Linguagem Infantil , Lateralidade Funcional , Testes de Linguagem , Idoso , Idoso de 80 Anos ou mais , Velocidade do Fluxo Sanguíneo , Encéfalo/irrigação sanguínea , Encéfalo/diagnóstico por imagem , Circulação Cerebrovascular , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Artéria Cerebral Média/diagnóstico por imagem , Artéria Cerebral Média/fisiologia , Fala/fisiologia , Ultrassonografia Doppler Transcraniana
11.
Cell ; 171(4): 865-876.e16, 2017 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-28965762

RESUMO

Environmental illumination spans many log units of intensity and is tracked for essential functions that include regulation of the circadian clock, arousal state, and hormone levels. Little is known about the neural representation of light intensity and how it covers the necessary range. This question became accessible with the discovery of mammalian photoreceptors that are required for intensity-driven functions, the M1 ipRGCs. The spike outputs of M1s are thought to uniformly track intensity over a wide range. We provide a different understanding: individual cells operate over a narrow range, but the population covers irradiances from moonlight to full daylight. The range of most M1s is limited by depolarization block, which is generally considered pathological but is produced intrinsically by these cells. The dynamics of block allow the population to code stimulus intensity with flexibility and efficiency. Moreover, although spikes are distorted by block, they are regularized during axonal propagation.


Assuntos
Retina/fisiologia , Animais , Axônios/metabolismo , Relógios Circadianos , Fenômenos Eletrofisiológicos , Luz , Transdução de Sinal Luminoso , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Células Ganglionares da Retina/citologia
12.
JMIR Res Protoc ; 6(5): e89, 2017 May 19.
Artigo em Inglês | MEDLINE | ID: mdl-28526665

RESUMO

BACKGROUND: There are an estimated three million people in the United Kingdom with chronic obstructive pulmonary disease (COPD), and the incidence of bronchiectasis is estimated at around 0.1% but is more common in COPD and severe asthma. Both COPD and bronchiectasis are characterized by exacerbations in which bacteria play a central role. Pseudomonas aeruginosa is isolated from sputum samples from 4% to 15% of adults with COPD and is more likely to be isolated from patients with severe disease. Earlier detection of exacerbations may improve morbidity and mortality by expediting treatment. Aseptika Ltd has developed a system for patients to self-monitor important physiological measurements including levels of physical activity, peak flow, forced expiratory volume (FEV1), and biomarkers for P aeruginosa in sputum. OBJECTIVE: We aim to test this system in 20 participants with P aeruginosa colonization and 10 controls with Haemophilus influenzae. METHODS: We plan to recruit 30 adult participants with COPD or non-CF bronchiectasis who have cultured P aeruginosa or H influenzae during an exacerbation in the last 6 months. They must produce sputum on most days and should have been stable for 4 weeks prior to entry. Daily data collected will include symptoms, health care usage, medication, weight, FEV1, physical activity level, blood pressure, oxygen saturation, and temperature. Sputum and urine samples will be provided daily. These data will be analyzed to assess predictive value in detecting upcoming exacerbations. Qualitative data will be gathered through self-administered questionnaires and semistructured interviews to gather information on participant coping and their use of the technology involved. RESULTS: Recruitment has been completed and results from the study should be available at the end of 2017. CONCLUSIONS: The SENSOR study aims to test a home-monitoring system in people with chronic airway infection and is currently underway.

13.
J Allergy Clin Immunol ; 138(1): 61-75, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-26851968

RESUMO

BACKGROUND: Disease heterogeneity in patients with severe asthma and its relationship to inflammatory mechanisms remain poorly understood. OBJECTIVE: We aimed to identify and replicate clinicopathologic endotypes based on analysis of blood and sputum parameters in asthmatic patients. METHODS: One hundred ninety-four asthmatic patients and 21 control subjects recruited from 2 separate centers underwent detailed clinical assessment, sputum induction, and phlebotomy. One hundred three clinical, physiologic, and inflammatory parameters were analyzed by using topological data analysis and Bayesian network analysis. RESULTS: Severe asthma was associated with anxiety and depression, obesity, sinonasal symptoms, decreased quality of life, and inflammatory changes, including increased sputum chitinase 3-like protein 1 (YKL-40) and matrix metalloproteinase (MMP) 1, 3, 8, and 12 levels. Topological data analysis identified 6 clinicopathobiologic clusters replicated in both geographic cohorts: young, mild paucigranulocytic; older, sinonasal disease; obese, high MMP levels; steroid resistant TH2 mediated, eosinophilic; mixed granulocytic with severe obstruction; and neutrophilic, low periostin levels, severe obstruction. Sputum IL-5 levels were increased in patients with severe particularly eosinophilic forms, whereas IL-13 was suppressed and IL-17 levels did not differ between clusters. Bayesian network analysis separated clinical features from intricately connected inflammatory pathways. YKL-40 levels strongly correlated with neutrophilic asthma and levels of myeloperoxidase, IL-8, IL-6, and IL-6 soluble receptor. MMP1, MMP3, MMP8, and MMP12 levels were associated with severe asthma and were correlated positively with sputum IL-5 levels but negatively with IL-13 levels. CONCLUSION: In 2 distinct cohorts we have identified and replicated 6 clinicopathobiologic clusters based on blood and induced sputum measures. Our data underline a disconnect between clinical features and underlying inflammation, suggest IL-5 production is relatively steroid insensitive, and highlight the expression of YKL-40 in patients with neutrophilic inflammation and the expression of MMPs in patients with severe asthma.


Assuntos
Asma/diagnóstico , Asma/metabolismo , Proteína 1 Semelhante à Quitinase-3/metabolismo , Metaloproteinases da Matriz/metabolismo , Adulto , Idoso , Asma/tratamento farmacológico , Teorema de Bayes , Biomarcadores , Estudos de Casos e Controles , Citocinas/metabolismo , Feminino , Humanos , Mediadores da Inflamação/metabolismo , Masculino , Inibidores de Metaloproteinases de Matriz/metabolismo , Pessoa de Meia-Idade , Testes de Função Respiratória , Fatores de Risco , Índice de Gravidade de Doença , Escarro/metabolismo , Adulto Jovem
14.
Proc Natl Acad Sci U S A ; 113(4): 874-9, 2016 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-26504225

RESUMO

Globally, large-bodied wild mammals are in peril. Because "megamammals" have a disproportionate influence on vegetation, trophic interactions, and ecosystem function, declining populations are of considerable conservation concern. However, this is not new; trophic downgrading occurred in the past, including the African rinderpest epizootic of the 1890s, the massive Great Plains bison kill-off in the 1860s, and the terminal Pleistocene extinction of megafauna. Examining the consequences of these earlier events yields insights into contemporary ecosystem function. Here, we focus on changes in methane emissions, produced as a byproduct of enteric fermentation by herbivores. Although methane is ∼ 200 times less abundant than carbon dioxide in the atmosphere, the greater efficiency of methane in trapping radiation leads to a significant role in radiative forcing of climate. Using global datasets of late Quaternary mammals, domestic livestock, and human population from the United Nations as well as literature sources, we develop a series of allometric regressions relating mammal body mass to population density and CH4 production, which allows estimation of methane production by wild and domestic herbivores for each historic or ancient time period. We find the extirpation of megaherbivores reduced global enteric emissions between 2.2-69.6 Tg CH4 y(-1) during the various time periods, representing a decrease of 0.8-34.8% of the overall inputs to tropospheric input. Our analyses suggest that large-bodied mammals have a greater influence on methane emissions than previously appreciated and, further, that changes in the source pool from herbivores can influence global biogeochemical cycles and, potentially, climate.


Assuntos
Clima , Ecossistema , Extinção Biológica , Herbivoria , Mamíferos/metabolismo , Metano/análise , Anaerobiose , Distribuição Animal , Animais , Animais Domésticos , Animais Selvagens , Bison , Digestão , Surtos de Doenças/história , Surtos de Doenças/veterinária , Europa (Continente) , Fermentação , Efeito Estufa , História Antiga , Atividades Humanas , Humanos , Gelo , Metano/metabolismo , Dispersão Vegetal , Plantas Comestíveis , Peste Bovina/história
15.
Sci Adv ; 1(6): e1500157, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26601216

RESUMO

Atmospheric aerosols, suspended solid and liquid particles, act as nucleation sites for cloud drop formation, affecting clouds and cloud properties-ultimately influencing the cloud dynamics, lifetime, water path, and areal extent that determine the reflectivity (albedo) of clouds. The concentration N d of droplets in clouds that influences planetary albedo is sensitive to the availability of aerosol particles on which the droplets form. Natural aerosol concentrations affect not only cloud properties themselves but also modulate the sensitivity of clouds to changes in anthropogenic aerosols. It is shown that modeled natural aerosols, principally marine biogenic primary and secondary aerosol sources, explain more than half of the spatiotemporal variability in satellite-observed N d. Enhanced N d is spatially correlated with regions of high chlorophyll a, and the spatiotemporal variability in N d is found to be driven primarily by high concentrations of sulfate aerosol at lower Southern Ocean latitudes (35(o) to 45(o)S) and by organic matter in sea spray aerosol at higher latitudes (45(o) to 55(o)S). Biogenic sources are estimated to increase the summertime mean reflected solar radiation in excess of 10 W m(-2) over parts of the Southern Ocean, which is comparable to the annual mean increases expected from anthropogenic aerosols over heavily polluted regions of the Northern Hemisphere.

16.
Glob Chang Biol ; 21(10): 3880-8, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25970851

RESUMO

Methane is an important greenhouse gas, but characterizing production by source sector has proven difficult. Current estimates suggest herbivores produce ~20% (~76-189 Tg yr(-1) ) of methane globally, with wildlife contributions uncertain. We develop a simple and accurate method to estimate methane emissions and reevaluate production by wildlife. We find a strikingly robust relationship between body mass and methane output exceeding the scaling expected by differences in metabolic rate. Our allometric model gives a significantly better fit to empirical data than IPCC Tier 1 and 2 calculations. Our analysis suggests that (i) the allometric model provides an easier and more robust estimate of methane production than IPCC models currently in use; (ii) output from wildlife is much higher than previously considered; and (iii) because of the allometric scaling of methane output with body mass, national emissions could be reduced if countries favored more, smaller livestock, over fewer, larger ones.


Assuntos
Poluentes Atmosféricos/análise , Efeito Estufa , Herbivoria , Mamíferos/fisiologia , Metano/análise , Animais , Peso Corporal , Monitoramento Ambiental , Modelos Teóricos
17.
PLoS One ; 7(11): e45785, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-23152748

RESUMO

Predators may affect prey population growth and community diversity through density mediated lethal and trait mediated non-lethal effects that influence phenotypic traits of prey. We tested experimentally the roles of thinning the density of prey (lethality) in the absence of predator cues and density and trait mediated effects (lethality + intimidation) of predatory midge Corethrella appendiculata on competing native and invasive mosquito prey. Predator-mediated reductions in prey and density reductions in the absence of C. appendiculata resulted in lower percent survivorship to adulthood and estimates of the finite rate of increase (λ') for invasive mosquito Aedes albopictus relative to that of controls. In most instances, thinning the density of prey in the absence, but not in the presence, of C. appendiculata cues resulted in lower survivorship to adulthood and λ' for native mosquito Aedes triseriatus relative to that of controls. Together, these results suggested trait mediated effects of C. appendiculata specific to each species of mosquito prey. Release from intraspecific competition attributable to density reductions in the absence, but not in the presence, of C. appendiculata enhanced growth and lengthened adult lifespan relative to that of controls for A. albopictus but not A. triseriatus. These results show the importance of predator-mediated density and trait mediated effects on phenotypic traits and populations of invasive and native mosquitoes. Species-specific differences in the phenotypic responses of prey may be due, in part, to longer evolutionary history of C. appendiculata with A. triseriatus than A. albopictus.


Assuntos
Culicidae/fisiologia , Comportamento Predatório , Animais , Evolução Biológica , Feminino , Larva , Masculino , Fenótipo , Densidade Demográfica , Dinâmica Populacional , Característica Quantitativa Herdável
18.
Dement Geriatr Cogn Dis Extra ; 2(1): 258-70, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22822408

RESUMO

BACKGROUND/AIM: The contribution of cerebrovascular dysfunction to the manifestation of dementia and cognitive decline in late life is gaining increased attention. We aimed to systematically review evidence for associations between dementia or aging and cerebrovascular function as measured using transcranial Doppler (TCD) examination. METHODS: A total of 1,172 articles were retrieved from PsychInfo and PubMed searches, and 34 relevant articles were identified using a variety of TCD methods. RESULTS: The pulsatility index (vessel resistance), spontaneous emboli and cerebrovascular reactivity to hyper-/hypocapnia appeared good discriminators of dementia. Aging was associated with a slowing in blood flow velocity. CONCLUSION: TCD ultrasonography is inexpensive, portable and well tolerated by aged and demented subjects. The technique stands to make a valuable contribution to the knowledge regarding the underlying functional biology of age-related cognitive change and dementia.

19.
Teach Learn Med ; 16(2): 133-8, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15446296

RESUMO

BACKGROUND: Performance-based assessments are often not reliable enough to be used as the sole method for determining a grade. PURPOSE: Using more than 1 assessment format has several advantages and can improve the quality of the information used to calculate course grades. To achieve a valid and reliable total score representing a combination of multiple assessment formats requires appropriate weighting procedures. METHODS: The classical test theory rationale and methodology for appropriately weighting in-course assessments is presented. Two reliablility-related equations are used to make decisions about weighting for a computerized performance assessment and a pattern recognition multiple-choice exam. RESULTS: Using the equations presented, the outcomes of various weighting scenarios are graphically presented. This technique produced weights that allow the instructor to obtain acceptable reliability while retaining a substantial emphasis on performance assessment. CONCLUSION: The weights assigned to component tests used to derive a total score have important reliability and validity implications. Course instructors need to consider both empirical reliability and logical validity evidence in determining component weights. When used in conjunction with classical methods, objectively scored item formats can augment performance assessments and enhance overall validity and reliability.


Assuntos
Educação de Graduação em Medicina/normas , Avaliação Educacional/métodos , Valores de Referência , Ensino/métodos , Simulação por Computador , Tomada de Decisões , Humanos , Modelos Estatísticos , Reconhecimento Automatizado de Padrão , Reprodutibilidade dos Testes , Estados Unidos
20.
Teach Learn Med ; 16(1): 51-9, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-14987175

RESUMO

BACKGROUND: Computer-based digital technology offers many opportunities in medical education. One type of digital technology, computer-based testing (CBT), has potentially wide application in undergraduate, graduate, and continuing medical education. DESCRIPTION: This articles describes the development of CBT in an undergraduate medical curriculum. EVALUATION: An early step in evaluating CBT is to be sure that the exam format is measuring the examinees' knowledge and not their comfort level or confidence with the technology. It is, therefore, important that the CBT reproduce or accommodate traditional test-taking behavior. CBT also provides for a number of enhancements not easily achieved with traditional paper-and-pencil exams. These include easier control and editing of exam items, better incorporation of testing into the learning environment using specific feedback, and enhancing the questions by incorporating multimedia. CBT does present some unique challenges in testing security, and this article discusses the approach to the security issues. In addition, before initiating CBT into a medical curriculum, the institution must understand the technical and infrastructure requirements for CBT. CONCLUSIONS: By providing a 5-year experience with CBT in the medical curriculum, this article hopes to facilitate discussions among medical educators in its appropriate application and evaluation.


Assuntos
Competência Clínica , Computadores , Avaliação Educacional/métodos , Faculdades de Medicina , Humanos , Estados Unidos
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