scholarly journals Dynamics of ammonia exchange with cut grassland: synthesis of results and conclusions of the GRAMINAE Integrated Experiment

2009 ◽  
Vol 6 (12) ◽  
pp. 2907-2934 ◽  
Author(s):  
M. A. Sutton ◽  
E. Nemitz ◽  
C. Milford ◽  
C. Campbell ◽  
J. W. Erisman ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Temporal Dynamics ◽  
Soil Surface ◽  
Ammonia Emission ◽  
Future Research ◽  
Transfer Model ◽  
Flux Divergence ◽  
Nh3 Emission ◽  
Flux Measurements

Abstract. Improved data on biosphere-atmosphere exchange are fundamental to understanding the production and fate of ammonia (NH3) in the atmosphere. The GRAMINAE Integrated Experiment combined novel measurement and modelling approaches to provide the most comprehensive analysis of the interactions to date. Major inter-comparisons of micrometeorological parameters and NH3 flux measurements using the aerodynamic gradient method and relaxed eddy accumulation (REA) were conducted. These showed close agreement, though the REA systems proved insufficiently precise to investigate vertical flux divergence. Grassland management had a large effect on fluxes: emissions increased after grass cutting (−50 to 700 ng m−2 s−1 NH3) and after N-fertilization (0 to 3800 ng m−2 s−1) compared with before the cut (−60 to 40 ng m−2 s−1). Effects of advection and air chemistry were investigated using horizontal NH3 profiles, acid gas and particle flux measurements. Inverse modelling of NH3 emission from an experimental farm agreed closely with inventory estimates, while advection errors were used to correct measured grassland fluxes. Advection effects were caused both by the farm and by emissions from the field, with an inverse dispersion-deposition model providing a reliable new approach to estimate net NH3 fluxes. Effects of aerosol chemistry on net NH3 fluxes were small, while the measurements allowed NH3-induced particle growth rates to be calculated and aerosol fluxes to be corrected. Bioassays estimated the emission potential Γ = [NH4+]/[H+] for different plant pools, with the apoplast having the smallest values (30–1000). The main within-canopy sources of NH3 emission appeared to be leaf litter and the soil surface, with Γ up to 3 million and 300 000, respectively. Cuvette and within-canopy analyses confirmed the role of leaf litter NH3 emission, which, prior to cutting, was mostly recaptured within the canopy. Measured ammonia fluxes were compared with three models: an ecosystem model (PaSim), a soil vegetation atmosphere transfer model (SURFATM-NH3) and a dynamic leaf chemistry model (DCC model). The different models each reproduced the main temporal dynamics in the flux, highlighting the importance of canopy temperature dynamics (Surfatm-NH3), interactions with ecosystem nitrogen cycling (PaSim) and the role of leaf surface chemistry (DCC model). Overall, net above-canopy fluxes were mostly determined by stomatal and cuticular uptake (before the cut), leaf litter emissions (after the cut) and fertilizer and litter emissions (after fertilization). The dynamics of ammonia emission from leaf litter are identified as a priority for future research.

The role of cows on OVOC exchanges of a pasture

2021 ◽  
Author(s):  
Bernard Heinesch ◽  
Colin Michel ◽  
Crist Amelynck ◽  
Niels Schoon ◽  
Ahsan Mozaffar ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Turbulent Flux ◽  
Flux Footprint ◽  
Leaf Injury ◽  
Footprint Model ◽  
Volatile Organic ◽  
Flux Measurements ◽  
Emission Models ◽  
Different Sources

<p>The presence of cows on a pasture considerably modifies exchanges of biogenic volatile organic compounds (BVOCs). By regulating the biomass present, they can have an impact on the constitutive flux (exchanges from soil and grass that are not induced by leaf wounding or trampling by cows) but they can also cause direct emissions from exhalation and indirect emissions by leaf injury (grazing), trampling and wastes. In this study conducted on the ICOS pasture site of Dorinne (Belgium), we disentangled these different sources/sinks for three oxygenated BVOCs commonly exchanged on grasslands (methanol, acetaldehyde and acetone), using a combination of turbulent flux measurements, enclosure flux measurements, tools to detect the presence and activity of cows in the footprint of the turbulent flux measurements and a flux footprint model. Direct exhalation emissions were low, representing only 2.3% and 10% of the spring total flux of methanol and acetone respectively. Comparison of grazed and non-grazed enclosures pointed out that emissions following leaf wounding were significant for all studied BVOCs, decreased exponentially with time to become negligible after maximum five days. Cow indirect emissions at the pasture scale (turbulent flux measurements) where likely dominated by grazing and were shown to be a major component of the total diurnal flux for each of the three studied BVOCs. Comparison with a hay meadow also showed that the temporal dynamics of those BVOC emissions were very different according to the grass management type, calling for specific parametrization in up-scaling emission models.</p>

scholarly journals Role of β-Catenin Activation Levels and Fluctuations in Controlling Cell Fate

Genes ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 176 ◽  
Author(s):  
Elisa Pedone ◽  
Lucia Marucci
Keyword(s):  
Signaling Pathway ◽  
Cell Fate ◽  
Temporal Dynamics ◽  
Cellular Systems ◽  
Future Research ◽  
Somatic Cell Reprogramming ◽  
Development In Vitro ◽  
Pluripotency Maintenance

Cells have developed numerous adaptation mechanisms to external cues by controlling signaling-pathway activity, both qualitatively and quantitatively. The Wnt/β-catenin pathway is a highly conserved signaling pathway involved in many biological processes, including cell proliferation, differentiation, somatic cell reprogramming, development, and cancer. The activity of the Wnt/β-catenin pathway and the temporal dynamics of its effector β-catenin are tightly controlled by complex regulations. The latter encompass feedback loops within the pathway (e.g., a negative feedback loop involving Axin2, a β-catenin transcriptional target) and crosstalk interactions with other signaling pathways. Here, we provide a review shedding light on the coupling between Wnt/β-catenin activation levels and fluctuations across processes and cellular systems; in particular, we focus on development, in vitro pluripotency maintenance, and cancer. Possible mechanisms originating Wnt/β-catenin dynamic behaviors and consequently driving different cellular responses are also reviewed, and new avenues for future research are suggested.

scholarly journals Survival, Dispersal, and Potential Soil-Mediated Suppression of Phytophthora ramorum in a California Redwood-Tanoak Forest

2009 ◽  
Vol 99 (5) ◽  
pp. 608-619 ◽  
Author(s):  
E. J. Fichtner ◽  
S. C. Lynch ◽  
D. M. Rizzo
Keyword(s):  
Leaf Litter ◽  
Leaf Tissue ◽  
Soil Surface ◽  
Phytophthora Ramorum ◽  
Infested Soil ◽  
Splash Dispersal ◽  
Pathogen Suppression ◽  
Rain Events ◽  
Leaf Disks

Because the role of soil inoculum of Phytophthora ramorum in the sudden oak death disease cycle is not well understood, this work addresses survival, chlamydospore production, pathogen suppression, and splash dispersal of the pathogen in infested forest soils. Colonized rhododendron and bay laurel leaf disks were placed in mesh sachets before transfer to the field in January 2005 and 2006. Sachets were placed under tanoak, bay laurel, and redwood at three vertical locations: leaf litter surface, litter–soil interface, and below the soil surface. Sachets were retrieved after 4, 8, 20, and 49 weeks. Pathogen survival was higher in rhododendron leaf tissue than in bay tissue, with >80% survival observed in rhododendron tissue after 49 weeks in the field. Chlamydospore production was determined by clearing infected tissue in KOH. Moist redwood-associated soils suppressed chlamydospore production. Rain events splashed inoculum as high as 30 cm from the soil surface, inciting aerial infection of bay laurel and tanoak. Leaf litter may provide an incomplete barrier to splash dispersal. This 2-year study illustrates annual P. ramorum survival in soil and the suppressive nature of redwood-associated soils to chlamydospore production. Infested soil may serve as primary inoculum for foliar infections by splash dispersal during rain events.

scholarly journals A process-based model for ammonia emission from urine patches, GAG (Generation of Ammonia from Grazing): description and sensitivity analysis

2016 ◽  
Vol 13 (6) ◽  
pp. 1837-1861 ◽  
Author(s):  
Andrea Móring ◽  
Massimo Vieno ◽  
Ruth M. Doherty ◽  
Johannes Laubach ◽  
Arezoo Taghizadeh-Toosi ◽  
...  
Keyword(s):  
Ammonia Volatilization ◽  
Regional Scale ◽  
Vital Role ◽  
Ammonia Emission ◽  
Rain Event ◽  
Nh3 Emission ◽  
New Process ◽  
Urine Patch ◽  
Higher Sensitivity

Abstract. In this paper a new process-based, weather-driven model for ammonia (NH3) emission from a urine patch has been developed and its sensitivity to various factors assessed. The GAG model (Generation of Ammonia from Grazing) is capable of simulating the TAN (total ammoniacal nitrogen) and the water content of the soil under a urine patch and also soil pH dynamics. The model tests suggest that ammonia volatilization from a urine patch can be affected by the possible restart of urea hydrolysis after a rain event as well as CO2 emission from the soil. The vital role of temperature in NH3 exchange is supported by our model results; however, the GAG model provides only a modest overall temperature dependence in total NH3 emission compared with the literature. This, according to our findings, can be explained by the higher sensitivity to temperature close to urine application than in the later stages and may depend on interactions with other nitrogen cycling processes. In addition, we found that wind speed and relative humidity are also significant influencing factors. Considering that all the input parameters can be obtained for larger scales, GAG is potentially suitable for field and regional scale application, serving as a tool for further investigation of the effects of climate change on ammonia emissions and deposition.

Coping Humor as a Mediator Between Emotional Intelligence and Job Satisfaction

2017 ◽  
Vol 16 (3) ◽  
pp. 155-159 ◽  
Author(s):  
Peizhen Sun ◽  
Jennifer J. Chen ◽  
Hongyan Jiang
Keyword(s):  
Job Satisfaction ◽  
Emotional Intelligence ◽  
Future Research ◽  
Satisfaction Scale ◽  
Primary School Teachers ◽  
Mediating Role ◽  
Regulation Of Emotion ◽  
The Relationship ◽  
Overall Job Satisfaction

Abstract. This study investigated the mediating role of coping humor in the relationship between emotional intelligence (EI) and job satisfaction. Participants were 398 primary school teachers in China, who completed the Wong Law Emotional Intelligence Scale, Coping Humor Scale, and Overall Job Satisfaction Scale. Results showed that coping humor was a significant mediator between EI and job satisfaction. A further examination revealed, however, that coping humor only mediated two sub-dimensions of EI (use of emotion and regulation of emotion) and job satisfaction. Implications for future research and limitations of the study are discussed.

Public Administration in the Islamic World: Considering the Importance of Religion, its Values and Culture

2019 ◽  
Vol 19 (2) ◽  
pp. 23-38
Author(s):  
Daniel Hummel
Keyword(s):  
Public Administration ◽  
Core Values ◽  
Comparative Perspective ◽  
Religious Values ◽  
Future Research ◽  
Islamic World ◽  
Salient Region ◽  
The People ◽  
Comparative Public Administration

A small but growing area of public administration scholarship appreciates the influence of religious values on various aspects of government. This appreciation parallels a growing interest in comparative public administration and indigenized forms of government which recognizes the role of culture in different approaches to government. This article is at the crossroads of these two trends while also considering a very salient region, the Islamic world. The Islamic world is uniquely religious, which makes this discussion even more relevant, as the nations that represent them strive towards legitimacy and stability. The history and core values of Islam need to be considered as they pertain to systems of government that are widely accepted by the people. In essence, this is being done in many countries across the Islamic world, providing fertile grounds for public administration research from a comparative perspective. This paper explores these possibilities for future research on this topic.

Moderating Role of Gender in the Relationship between Cognitive Errors and Anxiety among Adolescents

2020 ◽  
Vol 4 (1) ◽  
pp. 86-102
Author(s):  
Tasnim Rehna ◽  
Rubina Hanif ◽  
Muhammad Aqeel
Keyword(s):  
Mental Health Problems ◽  
Adolescent Psychopathology ◽  
Future Research ◽  
Cognitive Errors ◽  
Adolescent Anxiety ◽  
Study Results ◽  
The Status ◽  
Manifest Anxiety ◽  
The Relationship

Background: Widespread social paradigms on which the status variances are grounded in any society, gender plays pivotal role in manifestation of mental health problems (Rutter, 2007). A hefty volume of research has addressed the issue in adults nonetheless, little is vividly known about the role of gender in adolescent psychopathology. Sample: A sample of 240 adolescents (125 boys, 115 girls) aging 12-18 years was amassed from various secondary schools of Islamabad with the approval of the Federal Directorate of Education (FDE), relevant authorities of the schools and the adolescents themselves. Instruments: Taylor Manifest Anxiety Scale (Taylor & Spence, 1953) and Children’s Negative Cognitive Errors Questionnaire (CNCEQ) by Leitenberg et al., (1986) were applied in present study. Results: Multiple regression analysis revealed that cognitive errors jointly accounted for 78% of variance in predicting anxiety among adolescents. Findings also exhibited that gender significantly moderated the relationship between cognitive errors and adolescent anxiety. Implications of the findings are discoursed for future research and clinical practice.

Potential Role of Cytokines in Children with Acute Appendicitis and Acute Mesenteric Lymphadenitis

2011 ◽  
Vol 11 (1) ◽  
pp. 130-133
Author(s):  
Astra Zviedre ◽  
Arnis Engelis ◽  
Mohit Kakar ◽  
Aigars Pētersons
Keyword(s):  
Early Detection ◽  
Acute Appendicitis ◽  
Inflammatory Mediators ◽  
Potential Role ◽  
Clinical Symptoms ◽  
Future Research ◽  
Mesenteric Lymphadenitis ◽  
Proper Diagnosis ◽  
Near Future

Potential Role of Cytokines in Children with Acute Appendicitis and Acute Mesenteric Lymphadenitis Although, AAP and AML have different etiological factors, clinical symptoms are very much similar but treatment tactics in both the disease differ a lot. In case of AML, treatment is more conservative and does not require hospitalization while in case of AAP immediate hospitalization and maybe further surgery can be mandatory. With the identification of group of cytokines serum inflammatory mediators IL-8, IL-10, IL-12[p70], IL-17, TNF-a and MCP-1, it is believed early and proper diagnosis of AAP in the near future. Research of cytokines-serum inflammatory mediators has opened new opportunities for an early detection and differentiation of these two diseases in children.

Dietary Modifications in Fissure-in-ano: A Qualitative Study Based on Persian Medicine

2020 ◽  
Vol 16 (6) ◽  
pp. 860-865
Author(s):  
Sedigheh Tavakoli-Dastjerdi ◽  
Mandana Tavakkoli-Kakhki ◽  
Ali R. Derakhshan ◽  
Azam Teimouri ◽  
Malihe Motavasselian
Keyword(s):  
Modern Medicine ◽  
Integrative Approach ◽  
Future Research ◽  
Common Disease ◽  
Fissure In Ano ◽  
High Fiber ◽  
Baked Goods ◽  
Persian Medicine

Background: Anal fissure (AF) is a common disease associated with severe pain and reduced quality of life. Factors related to lifestyle, including diet and bowel habits, play a pivotal role in its pathogenesis. Most of the chronic fissures are not responsive to drugs and more likely to recur. Given the significance of diet in Persian medicine (PM), investigation on physiopathology and appropriate foods can be useful for decreases in AF symptoms and consequences. Objective: This study was intended to evaluate the role of diet in the formation and progression of AF from the perspective of PM. Methods: In this study, the most important resources of PM dating back to thousands of years were reviewed. All these textbooks contained a section on AF, its causes, and treatment. Further analysis was performed on these resources in comparison with databank and resources of modern medicine to develop a food-based strategy for AF management. Results: From the view of PM, the warmth and dryness of anus temperament accounted for AF. Both Persian and modern medicine identified constipation as another cause for AF. Therefore, avoidance from some foods and commercial baked goods was recommended. Both Persian and modern medicine forbad the following foods: potato, cabbage, cauliflower, pasta, beef, fish, and so forth. High fiber and oligo-antigen diets with some limitations have garnered more attention. Conclusion: An integrative approach is recommended employing both Persian and modern medicine for AF. There have been some evidence in this regard, however standardized clinical trials are required for future research.

Sign in / Sign up

Export Citation Format

Share Document