642 research outputs found
Indications of nitrogen-limited methane uptake in tropical forest soils
No full textIt is estimated that tropical forest soils contribute 6.2 Tg yr−1 (28%) to global methane (CH4) uptake, which is large enough to alter CH4 accumulation in the atmosphere if significant changes would occur to this sink. Elevated deposition of inorganic nitrogen (N) to temperate forest ecosystems has been shown to reduce CH4 uptake in forest soils, but almost no information exists from tropical forest soils even though projections show that N deposition will increase substantially in tropical regions. Here we report the results from two long-term, ecosystem-scale experiments in which we assessed the impact of chronic N addition on soil CH4 fluxes from two old-growth forests in Panama: (1) a lowland, moist (2.7 m yr−1 rainfall) forest on clayey Cambisol and Nitisol soils with controls and N-addition plots for 9–12 yr, and (2) a montane, wet (5.5 m yr−1 rainfall) forest on a sandy loam Andosol soil with controls and N-addition plots for 1–4 yr. We measured soil CH4 fluxes for 4 yr (2006–2009) in four replicate plots (40 m × 40 m each) per treatment using vented static chambers (four chambers per plot). CH4 fluxes from the lowland control plots and the montane control plots did not differ from their respective N-addition plots. In the lowland forest, chronic N addition did not lead to inhibition of CH4 uptake; instead, a negative correlation of CH4 fluxes with nitrate (NO3–) concentrations in the mineral soil suggests that increased NO3– levels in N-addition plots had stimulated CH4 consumption and/or reduced CH4 production. In the montane forest, chronic N addition also showed negative correlation of CH4 fluxes with ammonium concentrations in the organic layer, which suggests that CH4 consumption was N limited. We propose the following reasons why such N-stimulated CH4 consumption did not lead to statistically significant CH4 uptake: (1) for the lowland forest, this was caused by limitation of CH4 diffusion from the atmosphere into the clayey soils, particularly during the wet season, as indicated by the strong positive correlations between CH4 fluxes and water-filled pore space (WFPS); (2) for the montane forest, this was caused by the high WFPS in the mineral soil throughout the year, which may not only limit CH4 diffusion from the atmosphere into the soil but also favour CH4 production; and (3) both forest soils showed large spatial and temporal variations of CH4 fluxes. We conclude that in these extremely different tropical forest ecosystems there were indications of N limitation on CH4 uptake. Based on these findings, it is unlikely that elevated N deposition on tropical forest soils will lead to a rapid reduction of CH4 uptake
Immediate and long-term nitrogen oxide emissions from tropical forest soils exposed to elevated nitrogen input
No full textTropical nitrogen (N) deposition is projected to increase substantially within the coming decades. Increases in soil emissions of the climate-relevant trace gases NO and N2O are expected, but few studies address this possibility. We used N addition experiments to achieve N-enriched conditions in contrasting montane and lowland forests and assessed changes in the timing and magnitude of soil N-oxide emissions. We evaluated transitory effects, which occurred immediately after N addition, and long-term effects measured at least 6 weeks after N addition. In the montane forest where stem growth was N limited, the first-time N additions caused rapid increases in soil N-oxide emissions. During the first 2 years of N addition, annual N-oxide emissions were five times (transitory effect) and two times (long-term effect) larger than controls. This contradicts the current assumption that N-limited tropical montane forests will respond to N additions with only small and delayed increases in soil N-oxide emissions. We attribute this fast and large response of soil N-oxide emissions to the presence of an organic layer (a characteristic feature of this forest type) in which nitrification increased substantially following N addition. In the lowland forest where stem growth was neither N nor phosphorus (P) limited, the first-time N additions caused only gradual and minimal increases in soil N-oxide emissions. These first N additions were completed at the beginning of the wet season, and low soil water content may have limited nitrification. In contrast, the 9- and 10-year N-addition plots displayed instantaneous and large soil N-oxide emissions. Annual N-oxide emissions under chronic N addition were seven times (transitory effect) and four times (long-term effect) larger than controls. Seasonal changes in soil water content also caused seasonal changes in soil N-oxide emissions from the 9- and 10-year N-addition plots. This suggests that climate change scenarios, where rainfall quantity and seasonality change, will alter the relative importance of soil NO and N2O emissions from tropical forests exposed to elevated N deposition
An in-depth look into a tropical lowland forest soil: nitrogen-addition effects on the contents of N2O, CO2 and CH4 and N2O isotopic signatures down to 2-m depth
No full textAtmospheric nitrogen (N) deposition is rapidly increasing in tropical regions. We investigated how a decade of experimental N addition (125 kg N ha−1 year−1) to a seasonal lowland forest affected depth distribution and contents of soil nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4), as well as natural abundance isotopic signatures of N2O, nitrate (NO3 −) and ammonium (NH4 +). In the control plots during dry season, we deduced limited N2O production by denitrification in the topsoil (0.05–0.40 m) as indicated by: ambient N2O concentrations and ambient 15N-N2O signatures, low water-filled pore space (35–60%), and similar 15N signatures of N2O and NO3 −. In the subsoil (0.40–2.00 m), we detected evidence of N2O reduction to N2 during upward diffusion, indicating denitrification activity. During wet season, we found that N2O at 0.05–2.00 m was mainly produced by denitrification with substantial further reduction to N2, as indicated by: lighter 15N-N2O than 15N-NO3 − throughout the profile, and increasing N2O concentrations with simultaneously decreasing 15N-N2O enrichment with depth. These interpretations were supported by an isotopomer map and by a positive correlation between 18O-N2O and 15N-N2O site preferences. Long-term N addition did not affect dry-season soil N2O-N contents, doubled wet-season soil N2O-N contents, did not affect 15N signatures of NO3 −, and reduced wet-season 15N signatures of N2O compared to the control plots. These suggest that the increased NO3 − concentrations have stimulated N2O production and decreased N2O-to-N2 reduction. Soil CO2-C contents did not differ between treatments, implying that N addition essentially did not influence soil C cycling. The pronounced seasonality in soil respiration was largely attributable to enhanced topsoil respiration as indicated by a wet-season increase in the topsoil CO2-C contents. The N-addition plots showed reduced dry-season soil CH4-C contents and threshold CH4 concentrations were reached at a shallower depth compared to the control plots, revealing an N-induced stimulation of methanotrophic activity. However, the net soil CH4 uptake rates remained similar between treatments possibly because diffusive CH4 supply from the atmosphere largely limited CH4 oxidation.</p
An in-depth look into a tropical lowland forest soil: nitrogen-addition effects on the contents of N2O, CO2 and CH4 and N2O isotopic signatures down to 2-m depth (vol 111, pg 715, 2012)
No full textTelemonitoring for Chronic Heart Failure: Narrative Review of the 20-Year Journey From Concept to Standard Care in Germany
No full textBackground Chronic heart failure (CHF) is a major cause of morbidity and mortality worldwide, placing a significant burden on health care systems. The concept of telemedicine for CHF was first introduced in the late 1990s, and since 2010, studies have demonstrated its potential to improve patient outcomes and reduce health care costs. Over the following decade, technological advancements and changes in health care policy led to the development of more sophisticated telemedicine solutions for CHF, including remote patient management through invasive or noninvasive telemonitoring devices, mobile apps, and virtual consultations. Years of public funding in Germany have generated evidence that remote patient management improves outcomes for patients with CHF, such as quality of life, and reduces hospital admissions. Based on these data, the Federal Joint Committee (Gemeinsamer Bundesausschuss; G-BA) decided, independently of the current European Society of Cardiology recommendations, to incorporate telemedicine as a standard digital intervention for high-risk patients with reduced left ventricular ejection fraction in Germany in 2020. Objective This review aims to illustrate the journey from the initial concept through pioneering studies that led to telemedicine’s integration into standard care, and to share current experiences that have positioned Germany as a leader in cardiovascular telemedicine. Methods We review and discuss existing literature and evidence on the development and implementation of telemonitoring for CHF in Germany over the past 20 years. Relevant studies, reports, and guidelines were identified through a comprehensive search of electronic databases, including PubMed, Google Scholar, and specialized journals focused on CHF telemonitoring. Results Pioneering studies, such as the TIM-HF2 (Telemedical Interventional Management in Heart Failure II) and IN-TIME (Influence of Home Monitoring on Mortality and Morbidity in Heart Failure Patients with Impaired Left Ventricular Function) trials, demonstrated the effectiveness of remote patient management applications for patients with CHF in Germany and their applicability to current practices involving both invasive and noninvasive methods. Collaborations between researchers and technology developers overcame barriers, leading to sustainable improvements in patient care. Ongoing research on artificial intelligence applications for prioritizing and interpreting individual health data will continue to transform digital health care. Conclusions The establishment of telemedical care for patients with HF across Europe is likely to benefit from experiences in Germany, where significant improvements have been achieved in the care of patients with HF
Mirror Landing - As Remembered by Birgit Hult
No full textNotes - This account, Memories Mirror Landing by Birgit Hult, was compiled by Birgit's daughter, Jean Elvira Male, it documents the Hult family's experiences in Mirror Landing from 1912 - 1916. The Hults, who were originally from Sweden, arrived in Mirror Landing with two young children, a third child was born during their stay in Mirror Landing. Upon arriving in the area, the Hults made friends with the Gauthier family. The wives became good friends and would swap piano lessons for English lessons. Details of the log home where the family lived and the surrounding landscape were recalled. A memory about a large forest fire that occurred near the family home and dances that were attended in the town are discussed. Jean recalls her mother's memories regarding the animosity towards the North West Mounted Police that was felt by the people of Mirror Landing. The Hult family retained a strong connection to the Swedish heritage and practised many Swedish traditions, such as flying the Swedish flag and eating hot cross buns stuffed with Swedish Marzipan soaked in warm milk. Photos and a postcard written in 1915 are included in this article (10 pages
Knowing Through Popular Music in the Western Pacific Island World
No full textPacific Indigenous scholars have long emphasized the role of relationality for Pacific Islanders’ epistemologies. In this article, the author rethinks music in terms of the procedural knowledge inherent in and specific to popular music-making by exploring the latter as knowledge practices in Micronesia. This approach opens new vistas on the relationality at the heart of Western Pacific music-making. The author calls the musical manifestation of that relational capacity sound ties, suggesting that if, following Epeli Hau‘ofa, Oceania is “humanity rising from the depths of brine”, then it is not least the sound ties of knowing in and through music that mould that very humanity of people who are at home with the sea into aquapelagic assemblages that are, after all, so much more than water and land
EU-Behörde: Warum wir sie brauchen
No full textJan Cremers (UvT) contributed to the magazine Gute Arbeit (in German), published by BUND-Verlag. Together with co-author Birgit Krämer, he discusses the plans of the European Commission to introduce a European Labour Authority. They reflect on the possible contribution of such a body in checking respect for and compliance with labour legislation and conventional standards
Rude Girl de Birgit Weyhe et Priscilla Layne, une "ré-appropriation culturelle" à quatre mains ?
No full textInternational audienceThis article analyses the graphic novel Rude Girl (2022), a drawn (self-)portrait created collaboratively by Priscilla Layne, an African American of Caribbean descent and professor of German Studies, and Birgit Weyhe, a German comic book author. The work is first presented within the general context of Birgit Wehye’s albums, a former student of Anke Feuchtenberger and winner of the Max-und-Moritz Prize, in order to highlight some characteristics of how the author has thus far addressed cultural differences, including in the albums that recounted her ‘German’ childhood in Uganda and Kenya. The article then reexamines the controversy surrounding the album Madgermanes, perceived as ‘cultural appropriation’ by American Germanists. This controversy is revisited here in light of Priscilla Layne's publications, notably her book White Rebels in Black: German Appropriation of Black Popular Culture (2018), as well as her numerous reviews in the field of Black Studies and her translation of Olivia Wenzel's 1000 Serpentinen Angst. A thorough analysis of Rude Girl ultimately reveals a shift in the representation of cultural otherness, particularly through the means of (auto)biographical co-construction.Cet article analyse le roman graphique Rude girl (2022), (auto-)portrait dessiné, réalisé à quatre mains par Priscilla Layne, Afro-américaine d’origine caribéenne et professeure en études germaniques, et Birgit Weyhe, autrice allemande de bandes dessinées. L’oeuvre est d’abord replacée dans le contexte général des albums de Birgit Weyhe, élève d’Anke Feuchtenberger et lauréate du Prix Max-und-Moritz, pour dégager quelques caractéristiques de la façon dont l’autrice accueillait jusque-là la différence culturelle, y compris dans les albums qui faisaient le récit de son enfance « allemande » en Ouganda et au Kenya. L’article revient ensuite sur la polémique suscitée par l’album Madgermanes, perçu comme « appropriation culturelle » par les germanistes américains, polémique qui est ici revisitée à la lumière des publications de Priscilla Layne, notamment son ouvrage White Rebels in Black : German Appropriation of Black Popular Culture (2018), mais aussi ses nombreuses recensions dans le domaine des Black Studies, et sa traduction d’Olivia Wenzel, 1000 Serpentinen Angst. L’analyse approfondie de Rude girl permet finalement de mettre en évidence une césure dans la représentation de l’altérité culturelle, notamment par les moyens de la co-construction (auto-)biographique
Einfluss einer Substitutionstherapie mit Hydrocortison auf die kognitive Leistungsfähigkeit von Patienten mit Nebenniereninsuffizienz
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