438 research outputs found
ECONOMIC Potential of Renewable Energy in Vietnam's Power Sector
A bottom-up Integrated Resource Planning model is used to examine the economic potential of renewable energy in Vietnam’s power sector. In a baseline scenario without renewables, coal provides 44% of electricity generated from 2010 to 2030. The use of renewables could reduce that figure to 39%, as well as decrease the sector’s cumulative emission of CO2 by 8%, SO2 by 3%, and NOx by 4%. In addition,renewables could avoid installing 4.4GW in fossil fuel generating capacity, conserve domestic coal,decrease coal and gases imports, improving energy independence and security. Wind could become cost-competitive assuming high but plausible on fossil fuel prices, if the cost of the technology falls to 900 US$/kW
Legacy Phosphorus Implications in the Lake Pontchartrain Estuary Sediment Due to the 2011 Bonnet Carre Spillway Opening
Phosphorus (P) is an essential nutrient for life and excess P in aquatic systems can trigger algal blooms. Nutrient-rich Mississippi River water is diverted into the Lake Pontchartrain estuary (LPE) periodically through the Bonnet Carré Spillway (BCS) to avoid downstream flooding to the city of New Orleans, Louisiana and can significantly increase the internal P load in the sediment. A sequential P fractionation procedure was performed on sediments collected before the opening and after the closing of the 2011 BCS operation to understand the role of these large river diversions on P dynamics. Before the 2011 BCS opening, 10,368 Mt of P were found in the 0-10 cm sediment interval of the LPE. After the closure of the spillway, 13,293 Mt of P were measured in the 0-10 cm sediment interval. Total P significantly increased by 28% and a mass loading of 2,925 Mt of P was a consequence of the 42 days BCS opening. Sediment grain size analyzes revealed that majority of the finer sand and silt fractions were deposited near the BCS entrance, while the lighter clay fraction were transported tens of km towards the center of the LPE. Calculating the time for all newly added P from the 2011 BCS operation to flux out of the water column is important to understanding the impact on water quality of the LPE. Using a previously determined linear flux rate of ~517 Mt yr-1, it was estimated that ~6 years are needed to flux out the newly added sediment TP. While assuming a nonlinear model of flux rate, it is suggested that it would take a longer period of time to flux out all the newly P loaded from the sediments in the LPE. If the operations of these BCS opening are closely spaced in time (\u3c 6 years), there will be an increase of P in the sediments which could lead to changes in the trophic status of the LPE. This increase of TP in sediments can lead to an increase in the frequency and persistence of harmful algal blooms for many years after the spillway opening
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Hand, Foot and Mouth Disease in Vietnam: Epidemiology, Heart Rate Variability and Economic Burden
Over the last two decades, hand, foot and mouth disease (HFMD) has become a major clinical problem in Vietnam and the Asia-Pacific region. HFMD affects children, especially those under 5 years old, and has pandemic potential. Since 1997, there have been several outbreaks with severe clinical phenotypes, including brain stem encephalitis, attacking millions of children and causing thousands of deaths. Synthesizing data on epidemiology, etiology, disease pathophysiology and economic burden of this emerging infection remains essential to inform clinical management and health policy makers in prioritizing the development of intervention strategies.
Using data from >56,000 hospitalized cases over an 11 year period, I described the spatial and temporal distribution of HFMD in Ho Chi Minh City, the main hotspot of HFMD in Vietnam. I found that the disease started in the west and then moved to the south-east and finally came back the west of the city.
Results from a prospective multi-hospital based study conducted during 2015–2018 showed that of ~1200 enrolled patients, enterovirus A71 (EV-A71) was the most common HFMD pathogen detected, while coxsackievirus A6 (CV-A6) has emerged and replaced CV-A16 to become the second most common virus causing HFMD in Vietnam during the study period. Despite the emergence of other pathogens and the diversity of enterovirus serotypes (~20 serotypes) detected in HFMD patients, EV-A71 was the main cause of severe HFMD. Using long-term data synthesized as part of the research program, I also demonstrated for the first time that compared to EV-A71 subgenogroup B5, subgenogroup C4 was associated with more severe clinical phenotypes. Moreover, the predominance of subgenogroup C4 coincided with large, severe HFMD outbreaks in Vietnam (e.g. in 2011-12 and 2018). Collectively, the data suggest that an EV-A71 vaccine would be likely to substantially reduce the burden of HFMD, but a multivalent vaccine should be developed to control the ongoing HFMD epidemic because CV-A6, CV-A10 and CV-A16 were responsible for approximately 12% of severe HFMD cases and cross-reaction between these CV-As and EV-A71 is poor.
In order to improve our knowledge of HFMD pathophysiology, I used ECG signal recorded by a wearable device (e-Patch) to depict the distribution of heart rate variability (HRV) indices by severity and by detected pathogens and found that compared to mild disease HRV parameters reflecting parasympathetic nervous system activation in the severe group decreased whereas those mirroring sympathetic activity and autonomic nervous system imbalance increased. In a similar trend, compared to HFMD associated with non-EV-A71, HRV indices reflecting the imbalance between sympathetic and parasympathetic activation in HFMD associated with EV-A71 were significantly higher. This suggests that children with EV-A71 infection were more likely to have ANS imbalance. Alongside with these findings, the feasibility of this wearable device in children has brought promising applications in HFMD case management by early detection of severe disease in future.
To inform health policy makers in Vietnam about the burden of HFMD, I also estimated its economic burden. I showed that the total cost per case for mild and severe disease was 1326.7, respectively. Additionally, I also found that compared to CV-A infections, EV-A71 infection resulted in higher illness costs. At nationwide level, the total economic burden in Vietnam was estimated at >US$90 million for two-year period of 2016 – 2017
The potential for mitigation of CO2 emissions in Vietnam's power sector
This manuscript examines CO2 emissions from Vietnam's power sector using an expanded Integrated Resource Planning model. The potential effects of the following alternative policy options are examined: energy efficiency, favorably imported generation fuels, nuclear energy, renewable energy, and an internalized positive carbon value. The baseline in terms of cumulative CO2 emissions over 2010-2030 is 3.6 Gt. Lighting energy efficiency improvements offers 14% of no-regret abatement of CO2 emissions. Developing nuclear and renewable energy could help meet the challenges of the increases in electricity demand, the dependence on imported fuels for electricity generation in the context of carbon constraints applied in a developing country. When CO2 costs increase from 1 /t, building 10 GW of nuclear generation capacity implies an increase in abatement levels from 24% to 46%. Using renewable energy abates CO2 levels by between 14% and 46%. At 2 /tCO2, the model predicts an abatement of 1.4 Gt when efficient gas plants are substituted for coal generation and when the potential for wind energy is economically developed further than in the former model
Vers un modèle de vérification de la couche logique d'entreprise dans une architecture à 3 couches: modèle CPN-ECA
International audienceThis paper proposes a model for building a flexible system, which accepts and verifies the change on business logic, including both business processes and business rules, while the system has to cover the properties as reliability and reuse. In this model, the business process will be designed with Colour Petri Net and translated into a set of Event-Condition-Action rules, this set will be combined with business rules for checking the respect of a business process to the business rules in design and modifying the process. Hierarchical Colour Petri Net is also used to guarantee the reliability and to reuse properties of the system.Ce document propose un modèle pour la création d'un système flexible, qui accepte et vérifie les modifications apportées à la logique métier, y compris les processus et les règles métier, tandis que le système doit couvrir les propriétés en termes de fiabilité et de réutilisation. Dans ce modèle, le processus de gestion sera conçu avec un réseau Pétri coloré et traduit en un ensemble de règles Event-Condition-Action (ECA). Cet ensemble sera combiné à des règles de gestion permettant de vérifier le respect du processus de gestion par modifier le processus. Un réseau Pétri coloré hiérarchisé est également utilisé pour garantir la fiabilité et pour réutiliser les propriétés du systèm
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