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1.
BMC Prim Care ; 25(1): 162, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38730368

RESUMO

BACKGROUND: Interprofessional primary care teams (IPCTs) work together to enhance care. Despite evidence on the benefits of IPCTs, implementation remains challenging. This research aims to 1) identify and prioritize barriers and enablers, and 2) co-develop team-level strategies to support IPCT implementation in Nova Scotia, Canada. METHODS: Healthcare providers and staff of IPCTs were invited to complete an online survey to identify barriers and enablers, and the degree to which each item impacted the functioning of their team. Top ranked items were identified using the sum of frequency x impact for each response. A virtual knowledge sharing event was held to identify strategies to address local barriers and enablers that impact team functioning. RESULTS: IPCT members (n = 117), with a mix of clinic roles and experience, completed the survey. The top three enablers identified were access to technological tools to support their role, standardized processes for using the technological tools, and having a team manager to coordinate collaboration. The top three barriers were limited opportunity for daily team communication, lack of conflict resolution strategies, and lack of capacity building opportunities. IPCT members, administrators, and patients attended the knowledge sharing event (n = 33). Five strategies were identified including: 1) balancing patient needs and provider scope of practice, 2) holding regular and accessible meetings, 3) supporting team development opportunities, 4) supporting professional development, and 5) supporting involvement in non-clinical activities. INTERPRETATION: This research contextualized evidence to further understand local perspectives and experiences of barriers and enablers to the implementation of IPCTs. The knowledge exchange event identified actionable strategies that IPCTs and healthcare administrators can tailor to support teams and care for patients.


Assuntos
Relações Interprofissionais , Equipe de Assistência ao Paciente , Atenção Primária à Saúde , Nova Escócia , Humanos , Atenção Primária à Saúde/organização & administração , Equipe de Assistência ao Paciente/organização & administração , Inquéritos e Questionários , Comportamento Cooperativo , Masculino , Feminino , Disseminação de Informação/métodos , Adulto , Pessoal de Saúde
3.
BMC Prim Care ; 25(1): 25, 2024 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-38216867

RESUMO

BACKGROUND: Interprofessional primary care teams have been introduced across Canada to improve access (e.g., a regular primary care provider, timely access to care when needed) to and quality of primary care. However, the quality and speed of team implementation has not kept pace with increasing access issues. The aim of this research was to use an implementation framework to categorize and describe barriers and enablers to team implementation in primary care. METHODS: A narrative review that prioritized systematic reviews and evidence syntheses was conducted. A search using pre-defined terms was conducted using Ovid MEDLINE, and potentially relevant grey literature was identified through ad hoc Google searches and hand searching of health organization websites. The Consolidated Framework for Implementation Research (CFIR) was used to categorize barriers and enablers into five domains: (1) Features of Team Implementation; (2) Government, Health Authorities and Health Organizations; (3) Characteristics of the Team; (4) Characteristics of Team Members; and (5) Process of Implementation. RESULTS: Data were extracted from 19 of 435 articles that met inclusion/exclusion criteria. Most barriers and enablers were categorized into two domains of the CFIR: Characteristics of the Team and Government, Health Authorities, and Health Organizations. Key themes identified within the Characteristics of the Team domain were team-leadership, including designating a manager responsible for day-to-day activities and facilitating collaboration; clear governance structures, and technology supports and tools that facilitate information sharing and communication. Key themes within the Government, Health Authorities, and Health Organizations domain were professional remuneration plans, regulatory policy, and interprofessional education. Other key themes identified in the Features of Team Implementation included the importance of good data and research on the status of teams, as well as sufficient and stable funding models. Positive perspectives, flexibility, and feeling supported were identified in the Characteristics of Team Members domain. Within the Process of Implementation domain, shared leadership and human resources planning were discussed. CONCLUSIONS: Barriers and enablers to implementing interprofessional primary care teams using the CFIR were identified, which enables stakeholders and teams to tailor implementation of teams at the local level to impact the accessibility and quality of primary care.


Assuntos
Comunicação , Liderança , Humanos , Canadá , Disseminação de Informação , Atenção Primária à Saúde
4.
iScience ; 26(10): 107954, 2023 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-37954139

RESUMO

Critics judge quality based upon subjective characteristics of wine. These judgments are converted by critics into quantitative scores, which allow for comparison of vintages. This paper uses high resolution discrete and continuous time-based weather estimates at both a local and regional level to determine the role of weather conditions on producing high quality Bordeaux vintages, as determined by critics scores. By using discrete-time weather variables across local AOCs, this study reveals climate-quality relationships across the whole year, including previously ignored season effects. By using continuous time weather variables, we reinforce the evidence for these local effects by finding higher quality wine is made in years with higher rainfall, warmer temperatures; and earlier, shorter seasons. We propose management impacts of our results and suggest that as the climate continues to change, the quality of Bordeaux wines may continue to improve.

6.
Int J Health Policy Manag ; 12: 6901, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37579467

RESUMO

BACKGROUND: There is evidence of the benefits of integrated knowledge translation (IKT), yet there is limited research outlining the purpose of a knowledge broker (KB) within this approach. The Maritime SPOR SUPPORT Unit (MSSU) acts as a KB to support patient-oriented research across the Maritime provinces in Canada. The "Bridge Process" was developed by the Nova Scotia (NS) site as a strategy that involves work leading up to and following the Bridge Event. The process supports research addressing priority health topics discussed at the event by stakeholder groups. The objectives of this paper were to (1) describe the outputs/outcomes of this IKT approach; and (2) examine the role of the KB. METHODS: Quantitative data were collected from registration and evaluation surveys. Outputs are described with descriptive statistics. Qualitative data were collected through evaluation surveys and internal documents. Data related to KB tasks were categorized into three domains: (1) Knowledge Manager, (2) Linkage and Exchange Agent, and (3) Capacity Developer. RESULTS: The Bridge Process was implemented four times. A total of 314 participants including government, health, patient/citizen, community, and research personnel attended the events. We identified 24 priority topics, with 7 led by teams receiving support to complete related projects. Participants reported improved understanding of the research gaps and policy needs and engaged with individuals they would not have otherwise. Although patients/citizens attended each Bridge Event, only 61% of participants who completed an evaluation survey indicated that they were 'actively engaged in group discussion.' The KB's role was identified in all three domains including Knowledge Manager (eg, defining questions), Linkage and Exchange Agent (eg, engaging stakeholders), and Capacity Builder (eg, research interpretation). CONCLUSION: The MSSU facilitated an IKT approach by acting as a KB throughout the Bridge Process. This deliberative and sequential process served as an effective strategy to increase collaborative health research in the province.


Assuntos
Prioridades em Saúde , Ciência Translacional Biomédica , Humanos , Nova Escócia , Canadá , Inquéritos e Questionários , Pesquisadores
8.
Ann Surg Oncol ; 30(10): 6258-6265, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37535267

RESUMO

BACKGROUND: Early detection and intervention for breast cancer-related lymphedema (BCRL) significantly decreases progression to persistent BCRL (pBCRL). We aimed to provide long-term follow-up on our early detection with bioimpedance spectroscopy (BIS) and early home intervention demonstrating reduced pBCRL to guide surveillance recommendations. PATIENTS AND METHODS: In total, 148 female patients with breast cancer who had axillary lymph node dissection (ALND) from November 2014 to December 2017 were analyzed. Baseline BIS measurements and postoperative follow-up occurred every 3 months for 1 year, biannual for 1 year, and then annually. An elevated BIS triggered evaluation and initiation of at-home interventions with reassessment for resolution versus persistent BCRL (pBCRL). High-risk factors and timing were analyzed. RESULTS: Mean follow-up was 55 months, and 65 (44%) patients had an abnormal BIS. Of these, 54 (82%) resolved with home intervention. The overall pBCRL rate was 8%. Average time to first abnormal BIS was 11.7 months. None of the stage 0 patients (0/34) and only 5/25 (20%) of stage 1 patients had pBCRL. All of stage 2 and stage 3 patients (7/7) had pBCRL. pBCRL correlated with number of positive nodes, percentage of positive nodes, stage of lymphedema at diagnosis, and recurring abnormal BIS measurements (p < 0.05). CONCLUSIONS: We have shown that patients undergoing ALND with early BCRL identified by BIS who performed home interventions had an 8% pBCRL rate. Patients at high risk for pBCRL should have routine surveillance starting at 9 months postoperatively to identify an opportunity for early intervention.


Assuntos
Linfedema Relacionado a Câncer de Mama , Neoplasias da Mama , Linfedema , Feminino , Humanos , Neoplasias da Mama/complicações , Neoplasias da Mama/cirurgia , Seguimentos , Detecção Precoce de Câncer , Recidiva Local de Neoplasia/cirurgia , Linfedema Relacionado a Câncer de Mama/diagnóstico , Linfedema Relacionado a Câncer de Mama/etiologia , Linfedema Relacionado a Câncer de Mama/cirurgia , Linfedema/diagnóstico , Linfedema/etiologia , Linfedema/cirurgia , Excisão de Linfonodo/efeitos adversos , Fatores de Risco , Análise Espectral , Axila/patologia
9.
Explor Res Clin Soc Pharm ; 9: 100221, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36703714

RESUMO

Objectives: Pharmacists in Nova Scotia have had legislated authority to prescribe since 2011. This study aimed to describe the prescribing activities of pharmacists and the characteristics of patients who used pharmacist prescribing services. Methods: Using provincial health administrative databases we identified all community pharmacists who prescribed during the study period (October 2016 to March 2020) and correspondingly patients who had medications prescribed by a pharmacist during this period. Differences in, and predictors of the quantity of pharmacist prescribing over three fiscal years (April 2017 to March 2020) were described. Pharmacist prescribing activity was compared across the fiscal years of the study period with One-way Analysis of Variance. Negative binomial regression examined patient factors associated with use of pharmacist prescribing services. Analysis was carried out using SAS ENTERPRISE GUIDE v.8.2 (SAS Institute Cary, NC, USA). Key findings: A total of 1182 pharmacist prescribers were identified, who on average prescribed 24.6, 26.3, and 32.5 (p < 0.001) times per month in fiscal years 2018, 2019, 2020, respectively. The patient cohort contained 372,203 Nova Scotians over the 3-year period. For approved common and minor ailment prescribing in Nova Scotia, gastroesophageal reflux disease, vaccines (non-travel), contraceptive management, herpes zoster treatment, and allergic rhinitis had the highest number of prescriptions over the study period. Patient factors most strongly related to receiving more prescribing services by a pharmacist included receiving income assistance without copay (Incidence rate ratio (IRR) = 1.70), having >2 comorbidities (IRR = 1.51), male sex (IRR = 1.03), and greater age (IRR = 1.01). Those from an urban area (IRR = 0.92) or having a higher income (IRR = 0.95) received fewer pharmacist prescribing services (all p < 0.0001). Conclusions: Pharmacist prescribing increased over the 3-year period. Patients who were older and those with multiple comorbidities used pharmacist prescribing services most often. Prescribing activities represent an increasingly utilized role for pharmacists in primary care.

10.
Res Social Adm Pharm ; 19(1): 133-143, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36038458

RESUMO

BACKGROUND: Community pharmacists are positioned to improve access to medications through their ever-expanding role as prescribers, with this role becoming more pronounced during the COVID-19 pandemic. OBJECTIVES: Our research aimed to determine the extent of self-reported pharmacist prescribing pre-COVID-19 and during the COVID-19 pandemic, to identify barriers and facilitators to pharmacist prescribing, and to explore the relationship between these factors and self-reported prescribing activity. METHODS: A questionnaire based on the Theoretical Domains Framework (TDFv2) assessing self-reported prescribing was electronically distributed to all direct patient care pharmacists in NS (N = 1338) in July 2020. Wilcoxon signed-rank tests were used to examine temporal differences in self-reported prescribing activity. TDFv2 responses were descriptively reported as positive (agree/strongly agree), neutral (uncertain), and negative (strongly disagree/disagree) based on the 5-point Likert scale assessing barriers and facilitators to prescribing from March 2020 onward (i.e., 'during' COVID-19). Simple logistic regression was used to measure the relationship between TDFv2 domain responses and self-reported prescribing activity. RESULTS: A total of 190 pharmacists (14.2%) completed the survey. Over 98% of respondents reported prescribing at least once per month in any of the approved prescribing categories, with renewals being the most common activity reported. Since the pandemic, activity in several categories of prescribing significantly increased, including diagnosis supported by protocol (29.0% vs. 58.9%, p < 0.01), minor and common ailments (25.3% vs 34.7%, p = 0.03), preventative medicine (22.1% vs. 33.2%, p < 0.01). Amongst the TDFv2 domains, Beliefs about Consequences domain had the largest influence on prescribing activity (OR = 3.13, 95% CI 1.41-6.97, p < 0.01), with Social Influences (OR = 2.85, 95% CI 1.42-5.70, p < 0.01) being the next most influential. CONCLUSION: Self-reported prescribing by direct patient care community pharmacists in Nova Scotia increased during the COVID-19 pandemic, particularly for government-funded services. Key barriers to address, and facilitators to support pharmacist prescribing were identified and can be used to inform future interventions.


Assuntos
COVID-19 , Farmacêuticos , Humanos , COVID-19/epidemiologia , Pandemias , Autorrelato , Atitude do Pessoal de Saúde , Papel Profissional , Prescrições de Medicamentos
11.
BMJ Open ; 12(3): e057843, 2022 03 18.
Artigo em Inglês | MEDLINE | ID: mdl-35304399

RESUMO

INTRODUCTION: Children with medical complexity and their families are an important population of interest within the Canadian healthcare system. Despite representing less than 1% of the paediatric population, children with medical complexity require extensive care and account for one third of paediatric healthcare expenditures. Opportunities to conduct research to assess disparities in care and appropriate allocation of health resources relies on the ability to accurately identify this heterogeneous group of children. This study aims to better understand the population of children with medical complexity in the Canadian Maritimes, including Nova Scotia (NS), New Brunswick (NB) and Prince Edward Island (PEI). This will be achieved through three objectives: (1) Evaluate the performance of three algorithms to identify children with medical complexity in the Canadian Maritimes in administrative data; then using the 'best fit' algorithm (2) Estimate the prevalence of children with medical complexity in the Canadian Maritimes from 2003 to 2017 and (3) Describe patterns of healthcare utilisation for this cohort of children across the Canadian Maritimes. METHODS AND ANALYSIS: The research will be conducted in three phases. In Phase 1, an expert panel will codevelop a gold-standard definition of paediatric medical complexity relevant to the Canadian Maritime population. A two-gate validation process will then be conducted using NS data and the gold-standard definition to determine the 'best fit' algorithm. During phase 2 the 'best fit' algorithm will be applied to estimate the prevalence of children with medical complexity in NS, NB and PEI. Finally, in phase 3 will describe patterns of healthcare utilisation across the Canadian Maritimes. ETHICS AND DISSEMINATION: Ethics approval for this protocol was granted by the institutional research ethics board at the IWK Health Centre (REB # 1026245). A waiver of consent was approved. This study will use an integrated knowledge translation approach, where end users are involved in each stage of the project, which could increase uptake of the research into policy and practice. The findings of this research study will be submitted for publication and dissemination through conference presentations and with our end users.


Assuntos
Atenção à Saúde , Aceitação pelo Paciente de Cuidados de Saúde , Criança , Estudos de Coortes , Humanos , Nova Escócia/epidemiologia
12.
New Phytol ; 233(2): 670-686, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34087005

RESUMO

Heterogeneity has been observed in the responses of Arctic shrubs to climate variability over recent decades, which may reflect landscape-scale variability in belowground resources. At a northern fringe of tall shrub expansion (Yuribei, Yamal Peninsula, Russia), we sought to determine the mechanisms relating nitrogen (N) limitation to shrub growth over decadal time. We analysed the ratio of 15 N to 14 N isotopes in wood rings of 10 Salix lanata individuals (399 measurements) to reconstruct annual point-based bioavailable N between 1980 and 2013. We applied a model-fitting/model-selection approach with a suite of competing ecological models to assess the most-likely mechanisms that explain each shrub's individual time-series. Shrub δ15 N time-series indicated declining (seven shrubs), increasing (two shrubs) and no trend (one shrub) in N availability. The most appropriate model for all shrubs included N-dependent growth of linear rather than saturating form. Inclusion of plant-soil feedbacks better explained ring width and δ15 N for eight of 10 individuals. Although N trajectories were individualistic, common mechanisms of varying strength confirmed the N-dependency of shrub growth. The linear mechanism may reflect intense scavenging of scarce N; the importance of plant-soil feedbacks suggests that shrubs subvert the microbial bottleneck by actively controlling their environment.


Assuntos
Nitrogênio , Solo , Regiões Árticas , Clima , Ecossistema , Plantas
13.
Sci Total Environ ; 816: 151638, 2022 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-34774956

RESUMO

In contrast to marine ecosystems, the toxicity impact of microplastics in freshwater environments is poorly understood. This contribution reviews the literature on the range of effects of microplastics across and between trophic levels within the freshwater environment, including biofilms, macrophytes, phytoplankton, invertebrates, fish and amphibians. While there is supporting evidence for toxicity in some species e.g. growth reduction for photoautotrophs, increased mortality for some invertebrates, genetic changes in amphibians, and cell internalization of microplastics and nanoplastics in fish; other studies show that it is uncertain whether microplastics can have detrimental long-term impacts on ecosystems. Some taxa have yet to be studied e.g. benthic diatoms, while only 12% of publications on microplastics in freshwater, demonstrate trophic transfer in foodwebs. The fact that just 2% of publications focus on microplastics colonized by biofilms is hugely concerning given the cascading detrimental effects this could have on freshwater ecosystem function. Multiple additional stressors including environmental change (temperature rises and invasive species) and contaminants of anthropogenic origin (antibiotics, metals, pesticides and endocrine disruptors) will likely exacerbate negative interactions between microplastics and freshwater organisms, with potentially significant damaging consequences to freshwater ecosystems and foodwebs.


Assuntos
Microplásticos , Poluentes Químicos da Água , Animais , Biota , Ecossistema , Monitoramento Ambiental , Água Doce , Plásticos/toxicidade , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade
14.
Biol Lett ; 16(1): 20190441, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31964260

RESUMO

Ecosystem dynamics are driven by both biotic and abiotic processes, and perturbations can push ecosystems into novel dynamical regimes. Plant-plant, plant-soil and mycorrhizal associations all affect plant ecosystem dynamics; however, the direction and magnitude of these effects vary by context and their contribution to ecosystem resilience over long time periods remains unknown. Here, using a mathematical framework, we investigate the effects of plant feedbacks and mycorrhiza on plant-nutrient interactions. We show evidence for strong nutrient controlled feedbacks, moderation by mycorrhiza and influence on ecological resilience. We use this model to investigate the resilience of a longitudinal palaeoecological birch-δ15N interaction to plant-soil feedbacks and mycorrhizal associations. The birch-δ15N system demonstrated high levels of resilience. Mycorrhiza were predicted to increase resilience by supporting plant-nitrogen uptake and immobilizing excess nitrogen; in contrast, long-term enrichment in available nitrogen by plant-soil feedbacks is expected to decrease ecological resilience.


Assuntos
Micorrizas , Ecossistema , Nitrogênio , Nutrientes , Plantas , Solo
15.
16.
Ecol Lett ; 21(6): 814-825, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29601664

RESUMO

Plants and animals influence biomass production and nutrient cycling in terrestrial ecosystems; however, their relative importance remains unclear. We assessed the extent to which mega-herbivore species controlled plant community composition and nutrient cycling, relative to other factors during and after the Late Quaternary extinction event in Britain and Ireland, when two-thirds of the region's mega-herbivore species went extinct. Warmer temperatures, plant-soil and plant-plant interactions, and reduced burning contributed to the expansion of woody plants and declining nitrogen availability in our five study ecosystems. Shrub biomass was consistently one of the strongest predictors of ecosystem change, equalling or exceeding the effects of other biotic and abiotic factors. In contrast, there was relatively little evidence for mega-herbivore control on plant community composition and nitrogen availability. The ability of plants to determine the fate of terrestrial ecosystems during periods of global environmental change may therefore be greater than previously thought.


Assuntos
Ecossistema , Plantas , Animais , Biomassa , Herbivoria , Irlanda , Nitrogênio , Solo
17.
J Obstet Gynaecol Can ; 39(12): 1129-1136, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28780218

RESUMO

OBJECTIVE: To identify factors known in mid-pregnancy to be associated with risk of macrosomia (≥4000 g) among non-diabetic women and to develop a risk score to allow early identification of women at high risk. METHODS: Data were obtained from a population-based perinatal database and a hospital laboratory database in Nova Scotia, Canada. The study included singleton live births born to non-diabetic women between 1998 and 2005. Logistic regression was used to identify risk factors significantly associated with macrosomia. Risk scoring systems were developed for nulliparous and parous women separately and validated using the C-statistic. RESULTS: Of the 23 857 mother-infant pairs included in the study, 16.7% of the infants were macrosomic. In nulliparous women, seven risk factors were identified, of which pre-pregnancy weight ≥90 kg with an OR of 4.8 (95% CI: 3.9 to 6.0) contributed a greater number of points to the risk score. The resulting risk score corresponded to a range of estimated risk of 0.2% to 47.0% and had a C-statistic of 0.70. In parous women, the most points were assigned to women with a previous large birth (OR: 3.7; 95% CI: 3.2-4.0) and a pre-pregnancy weight ≥90 kg (OR: 3.8; 95% CI: 3.1-4.7). The resulting risk score corresponded to a range of estimated risk of 0.4% to 88.0% and had a C-statistic of 0.75. CONCLUSIONS: Macrosomia risk can be estimated by a simple calculation based on a woman's risk factor profile at mid-pregnancy.


Assuntos
Macrossomia Fetal , Adulto , Feminino , Humanos , Recém-Nascido , Masculino , Gravidez , Segundo Trimestre da Gravidez , Estudos Retrospectivos , Medição de Risco , Fatores de Risco , Adulto Jovem
18.
Ecol Appl ; 25(5): 1290-302, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26485956

RESUMO

The local ecological footprinting tool (LEFT) uses globally available databases, modeling, and algorithms to, remotely assess locally important ecological features across landscapes based on five criteria: biodiversity (beta-diversity), vulnerability (threatened species), fragmentation, connectivity, and resilience. This approach can be applied to terrestrial landscapes at a 300-m resolution within a given target area. Input is minimal (latitude and longitude) and output is a computer-generated report and series of maps that both individually and synthetically depict the relative value of each ecological criteria. A key question for any such tool, however, is how representative is the remotely obtained output compared to what is on the ground. Here, we present the results from comparing remotely- vs. field-generated outputs from the LEFT tool on two distinct study areas for beta-diversity and distribution of threatened species (vulnerability), the two fields computed by LEFT for which such an approach is feasible. The comparison method consists of a multivariate measure of similarity between two fields based on discrete wavelet transforms, and reveals consistent agreement across a wide range of spatial scales. These results suggest that remote assessment tools such as LEFT hold great potential for determining key ecological features across landscapes and for being utilized in preplanning biodiversity assessment tools.


Assuntos
Biodiversidade , Astronave , Cidades , Bases de Dados Factuais , Monitoramento Ambiental , Incerteza
19.
Nat Commun ; 5: 4914, 2014 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-25208610

RESUMO

Comparisons of climate model hindcasts with independent proxy data are essential for assessing model performance in non-analogue situations. However, standardized palaeoclimate data sets for assessing the spatial pattern of past climatic change across continents are lacking for some of the most dynamic episodes of Earth's recent past. Here we present a new chironomid-based palaeotemperature dataset designed to assess climate model hindcasts of regional summer temperature change in Europe during the late-glacial and early Holocene. Latitudinal and longitudinal patterns of inferred temperature change are in excellent agreement with simulations by the ECHAM-4 model, implying that atmospheric general circulation models like ECHAM-4 can successfully predict regionally diverging temperature trends in Europe, even when conditions differ significantly from present. However, ECHAM-4 infers larger amplitudes of change and higher temperatures during warm phases than our palaeotemperature estimates, suggesting that this and similar models may overestimate past and potentially also future summer temperature changes in Europe.

20.
Nature ; 495(7441): 352-5, 2013 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-23518563

RESUMO

Human activities have doubled the pre-industrial supply of reactive nitrogen on Earth, and future rates of increase are expected to accelerate. Yet little is known about the capacity of the biosphere to buffer increased nitrogen influx. Past changes in global ecosystems following deglaciation at the end of the Pleistocene epoch provide an opportunity to understand better how nitrogen cycling in the terrestrial biosphere responded to changes in carbon cycling. We analysed published records of stable nitrogen isotopic values (δ(15)N) in sediments from 86 lakes on six continents. Here we show that the value of sedimentary δ(15)N declined from 15,000 years before present to 7,056 ± 597 years before present, a period of increasing atmospheric carbon dioxide concentrations and terrestrial carbon accumulation. Comparison of the nitrogen isotope record with concomitant carbon accumulation on land and nitrous oxide in the atmosphere suggests millennia of declining nitrogen availability in terrestrial ecosystems during the Pleistocene-Holocene transition around 11,000 years before present. In contrast, we do not observe a consistent change in global sedimentary δ(15)N values during the past 500 years, despite the potential effects of changing temperature and nitrogen influx from anthropogenic sources. We propose that the lack of a single response may indicate that modern increases in atmospheric carbon dioxide and net carbon sequestration in the biosphere have the potential to offset recent increased supplies of reactive nitrogen in some ecosystems.


Assuntos
Ecossistema , Ciclo do Nitrogênio , Ciclo do Carbono , Sedimentos Geológicos/química , Modelos Teóricos , Isótopos de Nitrogênio/análise
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