Subject(s)
Biodiversity , Indigenous Peoples , Knowledge Management , Plants , Conservation of Natural ResourcesABSTRACT
OBJECTIVE: The burden of tuberculosis (TB) in migrant children and young people (CYP) is commonly overlooked, despite the increasing incidence of TB in migrant populations in the European region. This study aimed to examine the distribution and disease characteristics of TB among migrant and native-born CYP through analysis of data from the European Centre for Disease Prevention and Control (ECDC) surveillance system (TESSy). STUDY DESIGN: Retrospective database analysis. METHODS: A retrospective database analysis was conducted on all CYP TB cases (0-17 years) reported to TESSy (1995-2017), exploring distribution, site of TB, and presence of MDR-TB using multivariate analysis in R statistical software. RESULTS: Of the 73,176 CYP TB cases reported in the EU/EFTA (1995-2017), 24.4% (n = 17,879) occurred in migrant CYP and 75.6% (n = 55,297) occurred in native-born CYP. Migrant CYP were more likely (P < 0.001) to have pulmonary TB (OR: 1.90; 95% CI: 1.74-2.09) and unsuccessful treatment outcomes (OR: 2.05; 95% CI: 1.74-2.40) compared to native-born CYP. The proportion of extrapulmonary TB, compared to pulmonary TB across total CYP cases was higher than the existing evidence base. CONCLUSIONS: Overall, there were significant differences in the site of TB and treatment outcomes between migrant and native-born CYP. To improve outcomes, TB screening and detection practices should focus on facilitating care in migrant CYP. However, to better understand the implications of these findings on broader TB control, TB among CYP should be addressed more frequently in reports and research.
Subject(s)
Transients and Migrants , Tuberculosis , Humans , Retrospective Studies , Adolescent , Child , Child, Preschool , Infant , Male , Female , Transients and Migrants/statistics & numerical data , Tuberculosis/epidemiology , Europe/epidemiology , Infant, Newborn , Databases, Factual , Tuberculosis, Multidrug-Resistant/epidemiologyABSTRACT
OBJECTIVES: Refugees and migrants (R&Ms) exhibited higher risk of COVID-19 infection, and higher mortality rates during the pandemic. Acknowledging these risks, R&Ms early in the pandemic were identified by WHO as a priority vaccination group in need of protection. The aim of this study was to assess the vaccination roll-out and uptake among R&Ms residing in Reception Identification Centers (RICs) and Reception Sites (RSs) in Greece, relative to the general population. STUDY DESIGN: Nationwide observational study. METHODS: Retrospective analysis of national vaccination routine data and population census data, collected and triangulated from multiple official/governmental sources. Weekly vaccine roll-out and uptake were calculated for the general Greek population and the R&M population, through the first year of the vaccination programme in Greece (December 2020-December 2021). RESULTS: Vaccine roll-out among migrants in RICs/RSs started with a 22-week delay, compared to the general population. By the end of the first year of the vaccination programme in Greece in December 2021, the national vaccination uptake among registered R&Ms residing in official reception facilities was 27.3 % for 1st dose and 4.7 % for booster dose; considerably lower compared to the general population (69.5 % uptake for 1st dose, 64.7 % for 2nd dose, and 32.0 % for 3rd dose). CONCLUSION: Delayed vaccine roll-out and low vaccine uptake among R&Ms in Greece are signs of low prioritisation and implementation failures in the R&M vaccination strategy. In face of future public health threats, lessons should be learned, and vaccine equity should be insured for all socially vulnerable and high-risk population groups.
Subject(s)
COVID-19 , Refugees , Transients and Migrants , Humans , Greece/epidemiology , COVID-19 Vaccines , Retrospective Studies , COVID-19/epidemiology , COVID-19/prevention & control , VaccinationABSTRACT
INTRODUCTION: Acceptance of new technologies in health care, by those who use them as part of their role, is challenging with confounding contextual factors surrounding the acceptance of technology. As healthcare is rapidly digitising, stakeholder groups should be included in each stage of evaluation and implementation to allow opportunities to influence and contribute to digital health policies. This research employed a case study methodology to initiate an exploration into the factors associated with implementing a digital application into a mammography service. It examined the initial implementation and subsequent impact of the rollout of a digital application (VA) within a breast service in South Australia. METHODS: Stakeholders' opinions on team performance and feedback mechanisms of the digital application were evaluated through a staff questionnaire distributed through an online survey JISC. RESULTS: The incorporation of digitised technology into a service is evidently met with challenges. Although there is potential value in utelising automated feedback for workflow improvement and patient services, it appears imperative to provide targeted and developmental resources for educational development and staff well-being during the implementation phase. CONCLUSION: This case study approach delves into key discussion areas and serves as the initial insight into the implementation of a digital application. It could be regarded as a foundational reference for future evaluations of digital applications. IMPLICATIONS FOR PRACTICE: Research around digital fluency within the radiography profession requires further consideration. Under-utilisation or resistance may result in missed opportunities to enhance patient experiences and care outcomes and support staff wellbeing. Therefore, continued engagement and the encouragement of user feedback during the implementation phase are crucial to demonstrate future acceptance of digital applications in clinical settings.
Subject(s)
Delivery of Health Care , Health Facilities , HumansABSTRACT
Plants sustain human life. Understanding geographic patterns of the diversity of species used by people is thus essential for the sustainable management of plant resources. Here, we investigate the global distribution of 35,687 utilized plant species spanning 10 use categories (e.g., food, medicine, material). Our findings indicate general concordance between utilized and total plant diversity, supporting the potential for simultaneously conserving species diversity and its contributions to people. Although Indigenous lands across Mesoamerica, the Horn of Africa, and Southern Asia harbor a disproportionate diversity of utilized plants, the incidence of protected areas is negatively correlated with utilized species richness. Finding mechanisms to preserve areas containing concentrations of utilized plants and traditional knowledge must become a priority for the implementation of the Kunming-Montreal Global Biodiversity Framework.
Subject(s)
Biodiversity , Conservation of Natural Resources , Plant Dispersal , Plants , Humans , Africa , Ecosystem , Food , KnowledgeABSTRACT
SETTING: Migrants to Europe face a disproportionate burden of infections, including TB, yet little is known about the approach taken by primary and secondary care providers to screening and treatment. We therefore explored policy and practice relating to screening of active TB and latent TB infection (LTBI) in France.METHODS: We conducted an online national survey of French primary and secondary care physicians regarding their practices in relation to TB/LTBI screening among migrants.RESULTS: 367 physicians responded to the questionnaire among which 195 (53.1%) were primary care physicians, 126 (34.3%) were TB specialists in secondary care, and 46 (12.5%) other physicians; 303 (85.5%) were involved daily in the care of migrants. Most respondents recommended systematic TB screening with chest X-ray for migrants from medium and high-incidence countries (71.9%). Primary care physicians were less likely to offer screening than physicians in other settings (aOR 0.21, 95% CI 0.09-0.48). 220 (61.8%) offered LTBI screening for children (<15 years) and 34.0% for all migrants from high incidence countries.CONCLUSION: Improving awareness on TB screening is a critical next step to improve health outcomes in migrant groups and meet regional targets for tackling TB.
Subject(s)
Latent Tuberculosis , Transients and Migrants , Child , Europe , France/epidemiology , Humans , Latent Tuberculosis/diagnosis , Latent Tuberculosis/epidemiology , Mass ScreeningABSTRACT
It is increasingly recognised that head and neck cancer represents a spectrum of disease with a differential response to standard treatments. Although prognostic factors are well established, they do not reliably predict response. The ability to predict response early during radiotherapy would allow adaptation of treatment: intensifying treatment for those not responding adequately or de-intensifying remaining therapy for those likely to achieve a complete response. Functional imaging offers such an opportunity. Changes in parameters obtained with functional magnetic resonance imaging or positron emission tomography-computed tomography during treatment have been found to be predictive of disease control in head and neck cancer. Although many questions remain unanswered regarding the optimal implementation of these techniques, current, maturing and future studies may provide the much-needed homogeneous cohorts with larger sample sizes and external validation of parameters. With a stepwise and collaborative approach, we may be able to develop imaging biomarkers that allow us to deliver personalised, biologically adaptive radiotherapy for head and neck cancer.
Subject(s)
Head and Neck Neoplasms/pathology , Magnetic Resonance Imaging/methods , Positron Emission Tomography Computed Tomography/methods , Head and Neck Neoplasms/diagnostic imaging , Head and Neck Neoplasms/radiotherapy , Humans , Prognosis , Radiopharmaceuticals/metabolismABSTRACT
OBJECTIVES: World Health Organization (WHO) guidelines for health programmes and healthcare delivery are the foundation of its technical leadership in public health and essential to decision-making globally. A key function of guideline development is to identify areas in which further evidence is needed because filling these gaps will lead to future improvements in population health. The objective of this study was to examine the knowledge gaps and research questions for addressing those gaps generated through the WHO guideline development process, with the goal of informing future strategies for improving and strengthening the guideline development process. STUDY DESIGN: We did a systematic, retrospective analysis of research questions identified in the published guidelines. METHODS: We analyzed guidelines published between January 1, 2008, and December 31, 2018, by the Communicable Diseases Cluster in five disease areas: tuberculosis (TB), HIV, malaria, TB-HIV, and neglected tropical diseases (NTDs). Research questions were extracted independently by two researchers. We analyzed the distribution of research questions by disease and by topic category and did a qualitative assessment of optimum practice for research question generation during the guideline development process. RESULTS: A total of 48 guidelines were included: 26 on HIV, 1 on malaria, 11 on TB, 5 on TB/HIV, and 5 on NTDs. Overall, 36 (75%) guidelines encompassed a total of 360 explicit research questions; the remainder did not contain specific research questions. The number of research questions that focused on TB was 49, TB/HIV was 38, HIV was 250, and NTDs was 23. The number of research questions that focused on diagnosis was 43 (11.9%) of 360, prevention was 62 (17.2%), treatment was 103 (28.6%), good practice was 12 (3.3%), service delivery was 86 (23.8%), and other areas was 54 (15%). Research questions were often not formulated in a specific or actionable way and were hard to identify in the guideline. Examples of good practice identified by the review team involved the generation of specific and narrowly defined research questions, with accompanying recommendations for appropriate study design. CONCLUSIONS: The WHO must strengthen its approach to identifying and presenting research questions during the guideline development process. Ensuring access to research questions is a key next step in adding value to the guideline development process.
Subject(s)
Guidelines as Topic , Neglected Diseases , Research Design , Tropical Medicine , Tuberculosis , World Health Organization , Communicable Diseases , HIV Infections/complications , Humans , Malaria , Retrospective StudiesABSTRACT
INTRODUCTION: Despite considerable progress, just over half of the 37 million people eligible to start antiretroviral therapy (ART) have accessed treatment and millions of HIV-positive people still do not know their status. With demand for ART continuing to grow, meeting the ambitious 90-90-90 HIV treatment targets will depend on improved access to high-quality diagnostics to both diagnose infection and monitor treatment adherence in low and middle-income countries (LMICs). Robust projections of future demand for CD4, viral load (VL), HIV early-infant-diagnosis (EID) tests and HIV rapid diagnostic tests (RDTs) are needed as scale-up continues. METHODS: We estimate the current coverage for HIV diagnostics and project future demand to 2021 using a consolidated forecast using data on past coverage and current demand from a number of sources, from 130 predominantly LMIC countries. RESULTS: We forecast that the overall number of CD4 tests is expected to decline between now and 2021 as more countries adopt test-and-treat and shift to VL testing for patient monitoring. Our consolidated forecast projects a gradual decline in demand for CD4 tests to 16.6 million by 2021. We anticipate that demand for VL tests will increase to 28.5 million by 2021, reflecting the increasing number of people who will receive ART and the adoption of VL testing for patient monitoring. We expect that the demand for EID tests will grow more rapidly than in past years, driven by the implementation of testing at birth in programmes globally, in line with WHO guideline recommendations, doubling to 2.1 million tests by 2021. Demand for rapid diagnostic tests is also likely to increase, reaching 509 million tests by 2021. DISCUSSION: In order to achieve the ambitious 90-90-90 targets, it will be essential to maintain and improve access to CD4, VL, EID tests and RDTs. These projections provide insight into the global demand we can expect to see for these HIV monitoring and diagnostic tests, both in relation to historical trends, and the 90-90-90 targets. Our projections will better enable producers to ensure adequate supply, and to support procurement organisations in planning future funding and purchase plans to meet the anticipated demand. The findings highlight the ongoing need for governments and international funding bodies to prioritise improving capacity and access to HIV diagnostic and monitoring technologies in line with demand.
Subject(s)
Databases, Factual , Forecasting , HIV Infections , HIV-1 , Models, Biological , Anti-Retroviral Agents/therapeutic use , Epidemiological Monitoring , Female , HIV Infections/diagnosis , HIV Infections/drug therapy , HIV Infections/epidemiology , Humans , Male , Monitoring, PhysiologicABSTRACT
OBJECTIVES: Asylum seekers to Europe may come from war-torn countries where health systems have broken down, and there is evidence that asylum-seeking children have low coverage of childhood vaccinations, as well as uptake of immunisations in host countries. Such gaps in immunisation have important implications for effective national vaccination programmes. How we approach vaccination in children and adults entering Western Europe, where as a group they face barriers to health services and screening, is a growing debate; however, there are limited data on the vaccination status of these hard-to-reach communities, and robust evidence is needed to inform immunisation strategies. The aim of this study was to explore the vaccination status and needs of asylum-seeking children and adolescents in Denmark. STUDY DESIGN: We conducted a retrospective data analysis of anonymised patient records for asylum-seeking children and adolescents extracted from the Danish Red Cross database. METHODS: We retrospectively searched the Danish Red Cross database for children and adolescents (aged 3 months-17 years) with active asylum applications in Denmark as of October 28, 2015. Data were extracted for demographic characteristics, vaccination status and vaccinations needed by asylum-seeking children presenting to Red Cross asylum centres for routine statutory health screening. RESULTS: We explored the vaccination status and needs of 2126 asylum-seeking children and adolescents. About 64% of the study population were male and 36% were female. Eight nationalities were represented, where 33% of the total of children and adolescents were not immunised in accordance with Danish national guidelines, while 7% were considered partly vaccinated, and 60% were considered adequately vaccinated. Afghan (57% not vaccinated/unknown) and Eritrean (54% not vaccinated/unknown) children were the least likely to be vaccinated of all nationalities represented, as were boys (37% not vaccinated/unknown) compared with girls (27% not vaccinated/unknown) and children and adolescents aged between 12 and 17 years (48% not vaccinated/unknown) compared with 6- to 11-year olds (26%) and 0- to 5-year olds (22%). The health screenings resulted in 1328 vaccinations. The most commonly needed vaccines were diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b, (DTaP/IPV/Hib) which comprised 49% of the vaccines distributed, followed by the pneumococcal vaccine (Prevnar) (28%) and measles, mumps and rubella (MMR) vaccine (23%). CONCLUSIONS: The finding that nearly one-third of asylum-seeking children and adolescents in Denmark were in need of further vaccinations highlights the gaps in immunisation coverage in these populations. These results point to the need to improve access to health services and promote national vaccine programmes targeted at these communities to facilitate vaccination uptake and increase immunisation coverage to reduce the risk of preventable infectious diseases among asylum-seeking children.
Subject(s)
Health Services Needs and Demand , Refugees/statistics & numerical data , Vaccination/statistics & numerical data , Adolescent , Child , Child, Preschool , Denmark , Female , Humans , Infant , Infant, Newborn , Male , Retrospective StudiesABSTRACT
The WHO European Region has faced high rates of external and internal migration in recent years, with concerns that this is contributing to the burden of tuberculosis (TB), multidrug-resistant TB (MDR-TB) and TB/HIV coinfection in some countries. This report examines evidence of effective and efficient service packages for the prevention, diagnosis and treatment of TB to inform strategies to address the TB burden in refugee and migrant populations. Significant regional variations were identified in both migration levels and TB burden in refugees and migrants, as well as in approaches to TB control, with low quality of evidence in many cases. While it is unlikely that a single strategy/package will be effective for all situations, the evidence highlights some common approaches that could guide policy-making and service development. TB elimination targets for the Region will not be met unless inequalities in access to screening and treatment for migrants are addressed, alongside efforts to tackle TB globally.
Subject(s)
Humans , Male , Female , Tuberculosis/diagnosis , Tuberculosis/prevention & control , Tuberculosis, Multidrug-Resistant/complications , Latent Tuberculosis/prevention & control , Refugees , Transients and Migrants , Program Evaluation , EuropeABSTRACT
Risk assessment of central nervous system (CNS) infection patients is of key importance in predicting likely pathogens. However, data are lacking on the epidemiology globally. We performed a multicenter study to understand the burden of community-acquired CNS (CA-CNS) infections between 2012 and 2014. A total of 2583 patients with CA-CNS infections were included from 37 referral centers in 20 countries. Of these, 477 (18.5%) patients survived with sequelae and 227 (8.8%) died, and 1879 (72.7%) patients were discharged with complete cure. The most frequent infecting pathogens in this study were Streptococcus pneumoniae (n = 206, 8%) and Mycobacterium tuberculosis (n = 152, 5.9%). Varicella zoster virus and Listeria were other common pathogens in the elderly. Although staphylococci and Listeria resulted in frequent infections in immunocompromised patients, cryptococci were leading pathogens in human immunodeficiency virus (HIV)-positive individuals. Among the patients with any proven etiology, 96 (8.9%) patients presented with clinical features of a chronic CNS disease. Neurosyphilis, neurobrucellosis, neuroborreliosis, and CNS tuberculosis had a predilection to present chronic courses. Listeria monocytogenes, Staphylococcus aureus, M. tuberculosis, and S. pneumoniae were the most fatal forms, while sequelae were significantly higher for herpes simplex virus type 1 (p < 0.05 for all). Tackling the high burden of CNS infections globally can only be achieved with effective pneumococcal immunization and strategies to eliminate tuberculosis, and more must be done to improve diagnostic capacity.
Subject(s)
Central Nervous System Infections/epidemiology , Community-Acquired Infections/epidemiology , Population Surveillance , Adult , Age Factors , Aged , Aged, 80 and over , Central Nervous System Infections/etiology , Central Nervous System Infections/mortality , Community-Acquired Infections/etiology , Community-Acquired Infections/mortality , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Outcome Assessment, Health Care , Retrospective Studies , Young AdultSubject(s)
Mycobacterium tuberculosis , Tuberculosis, Multidrug-Resistant , Antitubercular Agents , Europe , HumansABSTRACT
Multidrug-resistant tuberculosis (MDR-TB) in low-incidence countries in Europe is more prevalent among migrants than the native population. The impact of the recent increase in migration to EU and EEA countries with a low incidence of TB (<20 cases per 100 000) on MDR-TB epidemiology is unclear. This narrative review synthesizes evidence on MDR-TB and migration identified through an expert panel and database search. A significant proportion of MDR-TB cases in migrants result from reactivation of latent infection. Refugees and asylum seekers may have a heightened risk of MDR-TB infection and worse outcomes. Although concerns have been raised around 'health tourists' migrating for MDR-TB treatment, numbers are probably small and data are lacking. Migrants experience significant barriers to testing and treatment for MDR-TB, exacerbated by increasingly restrictive health systems. Screening for latent MDR-TB is highly problematic because current tests cannot distinguish drug-resistant latent infection, and evidence-based guidance for treatment of latent infection in contacts of MDR patients is lacking. Although there is evidence that transmission of TB from migrants to the general population is low-it predominantly occurs within migrant communities-there is a human rights obligation to improve the diagnosis, treatment and prevention of MDR-TB in migrants. Further research is needed into MDR-TB and migration, the impact of screening on detection or prevention, and the potential consequences of failing to treat and prevent MDR-TB among migrants in Europe. An evidence-base is urgently needed to inform guidelines for effective approaches for MDR-TB management in migrant populations in Europe.
Subject(s)
Disease Transmission, Infectious/prevention & control , Emigration and Immigration , Infection Control , Tuberculosis, Multidrug-Resistant/epidemiology , Tuberculosis, Multidrug-Resistant/transmission , Antitubercular Agents/therapeutic use , Diagnostic Tests, Routine , Europe/epidemiology , Humans , Medication Adherence , Tuberculosis, Multidrug-Resistant/diagnosisABSTRACT
Mass gatherings pooling people from different parts of the world-the largest of which is to Mecca, Saudi Arabia, for Hajj-may impose risks for acquisition and dissemination of infectious diseases. A substantial number of pilgrims to Hajj and Umrah are Turkish citizens (456,000 in 2014) but data are lacking on scale of the problem. We did a retrospective cross-sectional multicenter study in Turkey to explore the range of infections among inpatients who had recently returned from the Arabian Peninsula. Our inclusion criteria were patients who had acquired an infection during their trip to an Arabian Peninsula country, or who became symptomatic within 1 week of their return. The data were collected retrospectively for January 1, 2013 and March 1, 2015. 185 Turkish patients were recruited to the study across 15 referral centers with travel associated infectious diseases after returning from Arabian Peninsula countries (predominantly Saudi Arabia 163 [88.1 %] for religious purposes 162 [87.5 %]). Seventy four (40.0 %) of them were ≥ 65 years old with numerous comorbidities including diabetes (24.3 %) and COPD (14.1 %). The most common clinical diagnosis was respiratory tract infections (169 [91.5 %]), followed by diarrheal diseases (13 [7 %]), and there was one case of MERS-CoV. Patients spent a median of 5 (3-7) days as hospital inpatients and overall mortality was 1.1 %. Returning travellers from the Arabian Peninsula present as inpatients with a broad range of infectious diseases similar to common community acquired infections frequently seen in daily medical practices in Turkey.
Subject(s)
Infections/epidemiology , Travel , Comorbidity , Critical Care , Cross-Sectional Studies , Female , Follow-Up Studies , Humans , Infections/diagnosis , Infections/etiology , Infections/therapy , Intensive Care Units , Male , Microbiological Techniques , Middle East , Retrospective Studies , Serologic Tests , TurkeyABSTRACT
BACKGROUND: The prognosis for hepatocellular carcinoma (HCC) is dependent upon tumour stage, performance status (PS), severity of underlying liver disease, and the availability of appropriate therapies. The unavailability of sorafenib may have a significantly adverse effect on the prognosis of UK patients with advanced HCC. During the study period, access to sorafenib was at the discretion of local health funding bodies, a process that may delay or deny access to the drug and that remains in place for Wales, Scotland, and Northern Ireland. Here, we attempt to address the impact of this system on patients with advanced HCC in the United Kingdom. METHODS: This is a retrospective study performed in the two largest specialist hepatobiliary oncology units in the United Kingdom. Funding applications were made to local funding bodies for patients with advanced HCC for whom sorafenib was considered appropriate (advanced HCC not suitable for loco-regional therapies, compensated chronic liver disease, PS 0-2). RESULTS: A total of 133 applications were made, of which 57 (43%) were approved and 76 (57%) declined. Demographics and prognostic factors were balanced between the two groups. This cohort had a number of adverse prognostic features: patients were predominantly PS 1-2; the majority had multifocal disease with the largest lesion being >5 cm; and macroscopic vascular invasion, metastases, and AFP >,000 ng ml(-1), were each present in one-third of cases. The median time from application to funding decision was 17 days (range 3-260 days). For the primary 'intention-to-treat' analysis, median overall survival was 4.1 months when funding was declined, and 9.5 months when funding was approved (hazard ratio (HR) 0.48; 95% CI 0.3186-0.7267; P=0.0005). CONCLUSION: These data support the use of sorafenib for patients with advanced HCC as an effective intervention. In the United Kingdom, this applies to a relatively small group of patients, estimated to total â¼800 per year who, unfortunately, do not survive long enough to themselves lobby for the availability of this drug. These data provide a comparison of sorafenib with supportive care and demonstrate the potential detrimental impact on patient outcomes of rationing health-care resources on the basis of cost.
Subject(s)
Antineoplastic Agents/supply & distribution , Carcinoma, Hepatocellular/drug therapy , Health Care Rationing/economics , Liver Neoplasms/drug therapy , Neoplasms, Multiple Primary/drug therapy , Niacinamide/analogs & derivatives , Phenylurea Compounds/supply & distribution , Adolescent , Adult , Aged , Aged, 80 and over , Antineoplastic Agents/economics , Antineoplastic Agents/therapeutic use , Carcinoma, Hepatocellular/mortality , Carcinoma, Hepatocellular/pathology , Cohort Studies , Female , Humans , Liver Neoplasms/mortality , Liver Neoplasms/pathology , Male , Middle Aged , Neoplasms, Multiple Primary/pathology , Niacinamide/economics , Niacinamide/supply & distribution , Niacinamide/therapeutic use , Phenylurea Compounds/economics , Phenylurea Compounds/therapeutic use , Retrospective Studies , Sorafenib , United Kingdom , Young AdultABSTRACT
Renewed interest in quantifying greenhouse gas emissions from soil has led to an increase in the application of chamber-based flux measurement techniques. Despite the apparent conceptual simplicity of chamber-based methods, nuances in chamber design, deployment, and data analyses can have marked effects on the quality of the flux data derived. In many cases, fluxes are calculated from chamber headspace vs. time series consisting of three or four data points. Several mathematical techniques have been used to calculate a soil gas flux from time course data. This paper explores the influences of sampling and analytical variability associated with trace gas concentration quantification on the flux estimated by linear and nonlinear models. We used Monte Carlo simulation to calculate the minimum detectable fluxes (α = 0.05) of linear regression (LR), the Hutchinson/Mosier (H/M) method, the quadratic method (Quad), the revised H/M (HMR) model, and restricted versions of the Quad and H/M methods over a range of analytical precisions and chamber deployment times (DT) for data sets consisting of three or four time points. We found that LR had the smallest detection limit thresholds and was the least sensitive to analytical precision and chamber deployment time. The HMR model had the highest detection limits and was most sensitive to analytical precision and chamber deployment time. Equations were developed that enable the calculation of flux detection limits of any gas species if analytical precision, chamber deployment time, and ambient concentration of the gas species are known.