scholarly journals Reach-Scale Model of Aquatic Vegetation Quantifies N Fate in a Bedrock-Controlled Karst Agroecosystem Stream

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2458
Author(s):  
Nolan L. Bunnell ◽  
William I. Ford ◽  
Alex W. Fogle ◽  
Joseph Taraba
Keyword(s):  
Management Practices ◽  
Aquatic Vegetation ◽  
Inorganic Nitrogen ◽  
Solution Space ◽  
Implementation Strategies ◽  
Water Quality Modeling ◽  
Scale Model ◽  
N Budget ◽  
Modeling Framework ◽  
Scenario Analyses

In-stream fate of nutrients in karst agroecosystems remains poorly understood. The significance of these streams is recognized given spring/surface water confluences have been identified as hotspots for biogeochemical transformations. In slow-moving streams high in dissolved inorganic nutrients, benthic and floating aquatic macrophytes are recognized to proliferate and drastically impact nutrient fate; however, models that quantify coupled interactions between these pools are limited. We present a reach-scale modeling framework of nitrogen dynamics in bedrock-controlled streams that accounts for coupled interactions between hydrology, hydraulics, and biotic dynamics and is validated using a multi-year, biweekly dataset. A fluvial N budget with uncertainty was developed to quantify transformation dynamics for the dissolved inorganic nitrogen (DIN) pool using a GLUE-like modeling framework, and scenario analyses were run to test for model function over variable environmental conditions. Results from a 10,000 run uncertainty analysis yielded 195 acceptable parameter sets for the calibration period (2000–2002), 47 of which were acceptable for the validation period (2003) (Nash-Sutcliffe Efficiency (NSE) > 0.65; percent bias (PBIAS) < ±15), with significantly different posterior parameter spaces for parameters including denitrification coefficients and duckweed growth factors. The posterior solution space yielded model runs with differing biomass controls on DIN, including both algae and duckweed, but suggested duckweed denitrifies at a rate that would place the bedrock agroecosystem stream on the high-end of rates reported in the literature, contradicting the existing paradigm about bedrock streams. We discuss broader implications for watershed-scale water quality modeling and implementation strategies of management practices for karst agroecosystems, particularly with respect to stream restoration.

Adapting Nitrogen Fertilization to Unpredictable Seasonal Conditions with the Least Impact on the Environment

2006 ◽  
Vol 16 (3) ◽  
pp. 408-412 ◽  
Author(s):  
Nicolas Tremblay ◽  
Carl Bélec
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Saturation Index ◽  
N Fertilization ◽  
Soil Conditions ◽  
Vegetable Crops ◽  
N Budget ◽  
Reference Plot ◽  
Weather Events ◽  
Primary Driver

Weather is the primary driver of both plant growth and soil conditions. As a consequence of unpredictable weather effects on crop requirements, more inputs are being applied as an insurance policy. Best management practices (BMPs) are therefore about using minimal input for maximal return in a context of unpredictable weather events. This paper proposes a set of complementary actions and tools as BMP for nitrogen (N) fertilization of vegetable crops: 1) planning from an N budget, 2) reference plot establishment, and 3) crop sensing prior to in-season N application based on a saturation index related to N requirement.

scholarly journals Genome-Scale Metabolic Network Analysis of the Opportunistic Pathogen Pseudomonas aeruginosa PAO1

2008 ◽  
Vol 190 (8) ◽  
pp. 2790-2803 ◽  
Author(s):  
Matthew A. Oberhardt ◽  
Jacek Puchałka ◽  
Kimberly E. Fryer ◽  
Vítor A. P. Martins dos Santos ◽  
Jason A. Papin
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Metabolic Network ◽  
Opportunistic Pathogen ◽  
Scale Model ◽  
Modeling Framework ◽  
Major Life ◽  
Metabolic Versatility ◽  
A Genome ◽  
Scale Properties ◽  
Genome Scale

ABSTRACT Pseudomonas aeruginosa is a major life-threatening opportunistic pathogen that commonly infects immunocompromised patients. This bacterium owes its success as a pathogen largely to its metabolic versatility and flexibility. A thorough understanding of P. aeruginosa's metabolism is thus pivotal for the design of effective intervention strategies. Here we aim to provide, through systems analysis, a basis for the characterization of the genome-scale properties of this pathogen's versatile metabolic network. To this end, we reconstructed a genome-scale metabolic network of Pseudomonas aeruginosa PAO1. This reconstruction accounts for 1,056 genes (19% of the genome), 1,030 proteins, and 883 reactions. Flux balance analysis was used to identify key features of P. aeruginosa metabolism, such as growth yield, under defined conditions and with defined knowledge gaps within the network. BIOLOG substrate oxidation data were used in model expansion, and a genome-scale transposon knockout set was compared against in silico knockout predictions to validate the model. Ultimately, this genome-scale model provides a basic modeling framework with which to explore the metabolism of P. aeruginosa in the context of its environmental and genetic constraints, thereby contributing to a more thorough understanding of the genotype-phenotype relationships in this resourceful and dangerous pathogen.

A novel synergistic multi-scale modeling framework to predict micro- and meso-scale damage behaviors of 2D triaxially braided composite

2021 ◽  
pp. 105678952110339
Author(s):  
Hongyong Jiang ◽  
Yiru Ren ◽  
Qiduo Jin
Keyword(s):  
Compressive Load ◽  
Scale Model ◽  
Modeling Framework ◽  
Braided Composite ◽  
Multi Scale ◽  
Scale Modeling ◽  
Bridge Model ◽  
Multi Scale Modeling ◽  
Transverse Damage ◽  
Meso Scale

A novel synergistic multi-scale modeling framework with a coupling of micro- and meso-scale is proposed to predict damage behaviors of 2D-triaxially braided composite (2DTBC). Based on the Bridge model, the internal stress and micro damage of constituent materials are respectively coupled with the stress and damage of tow. The initial effective elastic properties of tow (IEEP) used as the predefined data are estimated by micro-mechanics models. Due to in-situ effects, stress concentration factor (SCF) is considered in the micro matrix, exhibiting progressive damage accumulation. Comparisons of IEEP and strengths between the Bridge and Chamis’ theory are conducted to validate the values of IEEP and SCF. Based on the representative volume element (RVE), the macro properties and damage modes of 2DTBC are predicted to be consistent with available experiments and meso-scale simulation. Both axial and transverse damage mechanisms of 2DTBC under tensile or compressive load are revealed. Micro fiber and matrix damage accumulations have significant effects on the meso-scale axial and transverse damage of tows due to multi-scale coupling effects. Different from existing meso-/multi-scale models, the proposed multi-scale model can capture a crucial phenomenon that the transverse damage of tow is vulnerable to micro fiber fracture. The proposed multi-scale framework provides a robust tool for future systematic studies on constituent materials level to larger-scale aeronautical materials.

scholarly journals Climate Change and Curtailment: Evaluating Water Management Practices in the Context of Changing Runoff Regimes in a Snowmelt-Dominated Basin

Water ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1490 ◽  
Author(s):  
Amy Steimke ◽  
Bangshuai Han ◽  
Jodi Brandt ◽  
Alejandro Flores
Keyword(s):  
Management Practices ◽  
Hydrological Model ◽  
Water Rights ◽  
Climate Projections ◽  
Hydrological Response ◽  
Modeling Framework ◽  
Resource Managers ◽  
Alternative Future ◽  
Annual Discharge ◽  
Semi Arid

Hydrologic scientists and water resource managers often focus on different facets of flow regimes in changing climates. The objective of this work is to examine potential hydrological changes in the Upper Boise River Basin, Idaho, USA in the context of biophysical variables and their impacts a key variable governing administration of water resources in the region in an integrated way. This snowmelt-dominated, mountainous watershed supplies water to a semi-arid, agriculturally intensive, but rapidly urbanizing, region. Using the Envision integrated modeling framework, we created a hydrological model to simulate hydrological response to the year 2100 using six alternative future climate trajectories. Annual discharge increased from historical values by 6–24% across all simulations (with an average 13% increase), reflecting an increase in precipitation in the climate projections. Discharge peaked 4–33 days earlier and streamflow center of timing occurred 4–17 days earlier by midcentury. Examining changes in the date junior water rights holders begin to be curtailed regionally (the Day of Allocation), we found that the it occurs at least 14 days earlier by 2100 across all simulations, with one suggesting it could occur over a month earlier. These results suggest that current methods and policies of water rights accounting and management may need to be revised moving into the future.

scholarly journals Spatialized N budgets in a large agricultural Mediterranean watershed: high loading and low transfer

2012 ◽  
Vol 9 (1) ◽  
pp. 57-70 ◽  
Author(s):  
L. Lassaletta ◽  
E. Romero ◽  
G. Billen ◽  
J. Garnier ◽  
H. García-Gómez ◽  
...  
Keyword(s):  
River Basin ◽  
Management Practices ◽  
N Fertilization ◽  
Irrigated Agriculture ◽  
N Budget ◽  
Ebro River ◽  
N Retention ◽  
Management Measures ◽  
Mediterranean Regions ◽  
Food And Feed

Abstract. Despite the particular management practices and climate characteristics of the Mediterranean regions, the literature dealing with N budgets in large catchments subjected to Mediterranean conditions is scarce. The present study aims to deepen our knowledge on the N cycle within the Ebro River Basin (NE Spain) by means of two different approaches: (1) calculating a global N budget in the Ebro River Basin and (2) calculating a series of detailed regional budgets at higher geographical resolution. N inputs and outputs were spatialized by creating a map based on the most detailed information available. Fluvial and atmospheric N export was estimated together with N retention. The Ebro River Basin annually receives a relatively high amount of new N (5118 kg N km−2 yr−1), mostly in the form of synthetic fertilizers (50%). Although it is a highly productive catchment, the net N input as food and feed import is also high (33%). Only 8% of this N is finally exported to the delta zone. Several territorial units characterized by different predominant uses (rainfed agriculture, irrigated agriculture and pastures) have differentiated N dynamics. However, due to the high density of irrigation channels and reservoirs that characterize Mediterranean catchments, N retention is very high in all of them (median value, 91%). These results indicate that problems of eutrophication due to N delivery in the coastal area may not be too severe but that high N retention values may instead lead to problems within the catchment, such as pollution of aquifers and rivers, as well as high atmospheric emissions. The most promising management measures are those devoted to reducing agricultural surpluses through a better balanced N fertilization.

scholarly journals Implementation Gaps in Human Resource Performance Management Practices in the Ministry of Health and Child Care, Zimbabwe.

2021 ◽  
Vol 10 (2) ◽  
pp. 316-335
Author(s):  
Shikha Vyas-Doorgapersad ◽  
◽  
Mervis Chiware ◽  
Keyword(s):  
Child Care ◽  
Performance Management ◽  
Management Practices ◽  
Implementation Strategies ◽  
Research Approach ◽  
Successful Implementation ◽  
Ministry Of Health ◽  
Political Policy ◽  
Performance Results ◽  
Implementation Gaps

Any performance management (PM) practice implemented by an organisation has a direct impact on organisational performance and development; this paper therefore discusses challenges based on primary and secondary research findings, with the aim to explore how these findings correlate with how the successful implementation of PM practices is perceived and applied in the Ministry of Health and Child Care (MOHCC) in Zimbabwe. A qualitative research approach was used to collect data. The findings confirm that the implementation of PM has been marred by various challenges, which have, in turn, greatly affected performance results. Challenges identified by this study were, and continue to be, experienced at different levels of PM implementation strategies (e.g., at the formulation stage versus the implementation stage), and hence may hinder the effective implementation of PM practices in the MOHCC. The paper offers recommendations for consideration at political, policy, organisational, departmental, individual, and stakeholder levels.

scholarly journals Missing Links in Predicting Berry Sunburn in Future Vineyards

2021 ◽  
Vol 12 ◽  
Author(s):  
Christopher Bahr ◽  
Dominik Schmidt ◽  
Katrin Kahlen
Keyword(s):  
Environmental Conditions ◽  
Management Practices ◽  
Developmental State ◽  
Local Heat ◽  
Mitigation Strategies ◽  
Plant Management ◽  
Modeling Framework ◽  
Promising Tool ◽  
Berry Quality ◽  
Open Issues

Sunburn in grapevine berries is known as a recurring disorder causing severe yield losses and a decline in berry quality. The transition from healthy to sunburnt along a temporal trajectory is not fully understood. It is driven by light-boosted local heat impact and modulated by, e.g., past environments of the berry and its developmental state. Events of berry sunburn are often associated with heatwaves, indicating a link to climate change. In addition, the sensitivity of grapevine architecture to changing environmental condition indicates an urgent need to investigate and adapt mitigation strategies of berry sunburn in future vineyards. In this perspective, we want to identify missing links in predicting berry sunburn in vineyards and propose a modeling framework that may help us to investigate berry sunburn in future vineyards. For this, we propose to address open issues in both developing a model of berry sunburn and considering dynamic canopy growth, and canopy interaction with the environment and plant management such as shoot positioning or leaf removal. Because local environmental conditions drive sunburn, we aim at showing that identifying sunburn-reducing strategies in a vineyard under future environmental conditions can be supported by a modeling approach that integrates effects of management practices over time and takes grapevine architecture explicitly into account. We argue that functional-structural plant models may address such complex tasks. Once open issues are solved, they might be a promising tool to advance our knowledge on reducing risks of berry sunburn in silico.

scholarly journals Abatement vs. treatment for efficient diffuse source water pollution management in terrestrial-marine systems

2015 ◽  
Vol 72 (5) ◽  
pp. 730-737 ◽  
Author(s):  
P. C. Roebeling ◽  
M. C. Cunha ◽  
L. Arroja ◽  
M. E. van Grieken
Keyword(s):  
Water Pollution ◽  
Management Practices ◽  
Inorganic Nitrogen ◽  
Pollution Abatement ◽  
Source Water ◽  
Diffuse Source ◽  
Marine Systems ◽  
Pollution Management ◽  
Pollution Treatment ◽  
Water Pollution Management

Marine ecosystems are affected by water pollution originating from coastal catchments. The delivery of water pollutants can be reduced through water pollution abatement as well as water pollution treatment. Hence, sustainable economic development of coastal regions requires balancing of the marginal costs from water pollution abatement and/or treatment and the associated marginal benefits from marine resource appreciation. Water pollution delivery reduction costs are, however, not equal across abatement and treatment options. In this paper, an optimal control approach is developed and applied to explore welfare maximizing rates of water pollution abatement and/or treatment for efficient diffuse source water pollution management in terrestrial-marine systems. For the case of diffuse source dissolved inorganic nitrogen water pollution in the Tully-Murray region, Queensland, Australia, (agricultural) water pollution abatement cost, (wetland) water pollution treatment cost and marine benefit functions are determined to explore welfare maximizing rates of water pollution abatement and/or treatment. Considering partial (wetland) treatment costs and positive water quality improvement benefits, results show that welfare gains can be obtained, primarily, through diffuse source water pollution abatement (improved agricultural management practices) and, to a minor extent, through diffuse source water pollution treatment (wetland restoration).

Scaling-up sustainable intensification practices for rice production in East Africa

2020 ◽  
Author(s):  
Robert Burtscher ◽  
Taher Kahil ◽  
Mikhail Smilovic ◽  
Diana Luna ◽  
Jenan Irshaid ◽  
...  
Keyword(s):  
East Africa ◽  
Agricultural Production ◽  
Management Practices ◽  
Lake Victoria ◽  
Rice Production ◽  
Sustainable Intensification ◽  
Food Demand ◽  
Suitability Analysis ◽  
Lake Victoria Basin ◽  
Modeling Framework

&lt;p&gt;Food security has long been a challenge for East Africa region and is becoming a pressing issue for the coming decades because food demand is expected to increase considerably following rapid population and income growth. Agricultural production in the region is thus required to intensify, in a sustainable way, to keep up with food demand. However, many challenges face the sustainable intensification of the agricultural production including low productivity, inadequate management, small scale operations, and large climate variability. Several pilot initiatives, that involves a bundle of land and water management practices, have been introduced in the region to tackle such challenges. However, their large-scale implementation remains limited. In the framework of a research project which is jointly implemented by the International Institute for Applied System Analysis (IIASA), the Lake Victoria Basin Commission (LVBC) and the International Crops Research Institute for Semi-Arid Tropics (ICRISAT), we analyse up scaling opportunities for water and land management practices for the sustainable and resilient intensification of rice and fodder production systems in the extended Lake Victoria Basin in East Africa. The expected outcome of this project is to provide an improved understanding of up scaling of such practices through model simulations and integrated analysis of political economy aspects, governance and social and gender dimensions.&lt;/p&gt;&lt;p&gt;This paper presents an integrated upscaling modeling framework that combines biophysical suitability analysis and economic optimization. Several production system options (i.e., management practices) for rice intensification are examined at high-spatial resolution (0.5&amp;#176;x0.5&amp;#176;) in the extended Lake Victoria basin. The suitability analysis identifies suitable area for the production system options based on a combination of various biophysical factors such as climate, hydrology, vegetation and soil properties using the Global Agroecological Zones (GAEZ) model and the Community Water Model (CWaTM). The economic optimization identifies the optimal combination of those production systems that maximizes their overall contribution to agricultural economic benefits having satisfied various technical and resource constraints including commodity balance, land availability and suitability, water availability, labor availability and capital constraints. A set of socioeconomic (e.g., impact of population and income growth on food demand and agricultural productivity) and climate change (e.g., impact on water resources availability) scenarios based on combinations of the Shared Socioeconomic Pathways (SSPs), Representative Concentration Pathways (RCPs), and co-developed bottom-up policy scenarios, through stakeholders&amp;#8217; engagement with the Basin Commission (LVBC), have been utilized to simulate the modeling framework. Results of this study show the existence of significant opportunities for the sustainable intensification of rice production in East Africa. Moreover, the study identifies the key biophysical and economic factors that could enable the upscaling of sustainable land and water management practices for rice production in the region. Overall, this study demonstrates the capacity of the proposed upscaling modeling framework as a system approach to address the linkages between the intensification of agricultural production and the sustainable use of natural resources.&lt;/p&gt;

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