| 1. |
- Da, Chau Thi, et al.
(författare)
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Recycled pangasius pond sediments as organic fertilizer for vegetables cultivation : strategies for sustainable food production
- 2023
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Ingår i: Clean Technologies and Environmental Policy. - : Springer Science and Business Media LLC. - 1618-954X .- 1618-9558. ; 25:2, s. 369-380
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Tidskriftsartikel (refereegranskat)abstract
- Intensive Pangasius aquaculture farming contributes to increased income and profits in Vietnam, but is also associated with many environmental problems, including pollution from nutrient-rich water and sediments that are released into the environment. This article investigates the feasibility of using Pangasius pond sediments (PPS) in combination with amendments of rice straw (RS) to fertilize cucumber (Cucumis sativus L.) and water spinach (Ipomoea aquatica Forssk) plant. The results showed that mixing a ratio of 30% PPS with 70% RS produced the highest nutrient concentrations. The study demonstrates that organic fertilizer produced from PPS in combination with chemical fertilizer can replace 2575% of the inorganic fertilizers used as a nutrient source for cucumber and water spinach, and also increase the vegetable production. The highest yields were found for treatment PPS-3 (a combination of 50% chemical fertilizer and 50% organic fertilizer used on cucumber), and for treatment PPSRS-4 (a combination of 25% chemical fertilizer and 75% organic fertilizer used on water spinach) in both the wet and dry season (P˂0.05). The lowest yields were found when growing cucumbers and water spinach either with 100% organic fertilizer (the treatment PPS-5) or with 100% chemical fertilizer (the control treatment PPS-1), respectively (P˂0.05). Overall, the results indicated that the recycling of PPS as organic fertilizer and chemical fertilizer in combination for vegetable cultivation is more environmentally friendly as compared to using only chemical fertilizers.
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| 2. |
- Nguyen, Thanh N, et al.
(författare)
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Global Impact of the COVID-19 Pandemic on Stroke Volumes and Cerebrovascular Events: A 1-Year Follow-up.
- 2023
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Ingår i: Neurology. - 1526-632X. ; 100:4
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Tidskriftsartikel (refereegranskat)abstract
- Declines in stroke admission, IV thrombolysis (IVT), and mechanical thrombectomy volumes were reported during the first wave of the COVID-19 pandemic. There is a paucity of data on the longer-term effect of the pandemic on stroke volumes over the course of a year and through the second wave of the pandemic. We sought to measure the effect of the COVID-19 pandemic on the volumes of stroke admissions, intracranial hemorrhage (ICH), IVT, and mechanical thrombectomy over a 1-year period at the onset of the pandemic (March 1, 2020, to February 28, 2021) compared with the immediately preceding year (March 1, 2019, to February 29, 2020).We conducted a longitudinal retrospective study across 6 continents, 56 countries, and 275 stroke centers. We collected volume data for COVID-19 admissions and 4 stroke metrics: ischemic stroke admissions, ICH admissions, IVT treatments, and mechanical thrombectomy procedures. Diagnoses were identified by their ICD-10 codes or classifications in stroke databases.There were 148,895 stroke admissions in the 1 year immediately before compared with 138,453 admissions during the 1-year pandemic, representing a 7% decline (95% CI [95% CI 7.1-6.9]; p < 0.0001). ICH volumes declined from 29,585 to 28,156 (4.8% [5.1-4.6]; p < 0.0001) and IVT volume from 24,584 to 23,077 (6.1% [6.4-5.8]; p < 0.0001). Larger declines were observed at high-volume compared with low-volume centers (all p < 0.0001). There was no significant change in mechanical thrombectomy volumes (0.7% [0.6-0.9]; p = 0.49). Stroke was diagnosed in 1.3% [1.31-1.38] of 406,792 COVID-19 hospitalizations. SARS-CoV-2 infection was present in 2.9% ([2.82-2.97], 5,656/195,539) of all stroke hospitalizations.There was a global decline and shift to lower-volume centers of stroke admission volumes, ICH volumes, and IVT volumes during the 1st year of the COVID-19 pandemic compared with the prior year. Mechanical thrombectomy volumes were preserved. These results suggest preservation in the stroke care of higher severity of disease through the first pandemic year.This study is registered under NCT04934020.
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| 3. |
- Thanh, Dang Trung, et al.
(författare)
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Effects of organic fertilizers produced from fish pond sediment on growth performances and yield of Malabar and Amaranthus vegetables
- 2023
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Ingår i: Frontiers in Sustainable Food Systems. - : Frontiers Media SA. - 2571-581X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The increasing intensification of aquaculture production requires the development of strategies to reduce its environmental impacts such as the pollution caused by the discharge of nutrient-rich sediments into local water bodies. This research was undertaken to investigate and evaluate the effect of using organic fertilizers produced from the pond sludge of freshwater snakehead fish (Channa striata) composted with organic amendments of peanut shells and coir fiber on growth performance indices and yields of Malabar spinach (Basella alba L.) and Amaranthus cruentus (Amaranthus L.) vegetables in the dry and wet seasons. An organic fertilizer quality experiment showed that the richest nutrient contents of the produced organic fertilizer were achieved when using 30% sludge mixed with 70% organic amendments (50% peanut shells + 50% coir fiber). This was selected and used for a vegetable cultivation experiment. For the reference treatment, only chemical fertilizer was applied, while in the other four treatments, 25, 50, 75, and 100% of the chemical fertilizer were substituted with the organic fertilizer. A 25–50% reduction in the chemical fertilizer application resulted in better growth performance indices and final yields than the other treatments, including the reference treatment, for both crops. The highest yields of Malabar spinach and Amaranthus cruentus vegetables were found in Treatment 3 (50% chemical fertilizer combined with 50% organic fertilizer), followed by Treatment 2 (25% organic fertilizer combined with 75% inorganic fertilizer) (P < 0.05). The results show that the reuse of sludge from snakehead fish ponds mixed with agricultural by-products as organic fertilizer for vegetables not only improves vegetable productivity but also reduces the costs of chemical fertilizer and decreases environmental pollution.
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| 4. |
- Cuc, Nguyen Thi Thu, et al.
(författare)
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Hot water treatment prevents Aphelenchoides besseyi damage to Polianthes tuberosa crops in the Mekong Delta of Vietnam
- 2010
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Ingår i: Crop Protection. - 0261-2194. ; 29:6, s. 599-602
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Tidskriftsartikel (refereegranskat)abstract
- Polianthes tuberosa is a commercially valuable flower crop in the Mekong Delta of Vietnam that is propagated by the harvesting and planting of bulbs. The cultivation of P. tuberosa is infected by an endemic Aphelenchoides besseyi nematode that damages a high proportion of plants and persists within the bulbs. Here we report on the comparison of hot water and pesticide treatments as control methods to protect P. tuberosa from A. besseyi damage, and conclude that a hot water treatment consisting of soaking bulbs in water for 30 minutes at 57 °C is the most efficacious method to produce healthy flowers in a cost-effective manner.
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| 5. |
- Nguyen-Tien, Thang, et al.
(författare)
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Knowledge and practice on prevention of mosquito-borne diseases in livestock-keeping and non-livestock-keeping communities in Hanoi city, Vietnam : A mixed-method study
- 2021
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 16:2
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Tidskriftsartikel (refereegranskat)abstract
- Mosquito-borne diseases (MBDs) are causing high morbidity and mortality for humans. Urban livestock keeping is still common in cities around the world. The animals may serve as reservoirs for zoonotic MBDs, which increase the risks for humans. Here we assess the knowledge and practices related to MBDs in households with livestock and without livestock and explore the perceptions of the health care sector about MBDs and livestock keeping in Hanoi city of Vietnam in a cross-sectional study. A quantitative survey was conducted including 513 households with and without livestock-keeping in six districts and complemented with qualitative surveys with four health staff from Hanoi Center of Disease Control and three district health centers. The quantitative survey indicated that the participants possessed basic knowledge on MBDs with an average score of 18.3 out of 35, of which non-livestock-keeping households had a better knowledge than households keeping livestock (p<0.05). Both household categories had low score, 3.5 out of 11, regarding preventive practices against MBDs. The negative binomial model showed that occupation and location of living were factors associated to the knowledge on MBDs. Farmers were likely to have better preventive practices as compared to office workers (p<0.05). Those who had better knowledge also had more adequate preventive practices against MBDs (p<0.001). The qualitative survey revealed that livestock keeping was determined as increasing risks of MBDs due to the increase of mosquito population. It is recommended that community campaigns to raise the awareness and change behavior on MBDs should be organized based on collaboration between the health sector and the veterinary sector for households with and without livestock living in central urban and peri-urban areas. Further studies are needed to confirm the association between urban livestock keeping and potential increasing risks of MBDs such as dengue and Japanese encephalitis.
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| 6. |
- Tran, Thien Thanh, et al.
(författare)
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Performance analysis and optimal relay position of cognitive spectrum-sharing dual-hop decode-and-forward networks
- 2013
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Konferensbidrag (refereegranskat)abstract
- The performance of cognitive networks (CNs) has been significantly improved by deploying a third-party, namely relay, to assist the direct communication. However, under a limited transmit power governed by the maximum tolerable interference at the primary network, the cognitive relay network still suffers a performance loss compared to its non-cognitive counterpart. To alleviate this shortcoming, this paper has pro-posed a technique to optimally deploy the relay in CNs. In particular, by assuming the decode-and-forward (DF) relay, we first derive an exact expression for the outage probability (OP) of CNs with spectrum-sharing environment over Nakagami-m channels. Then, using the exact formula, we obtain the asymptotic OP expression which further reveals the impact of networks' parameters on the performance. In addition, the optimal relay placement, i.e., minimizing the system OP, is also investigated by utilizing the asymptotic OP result. We have shown through some representative scenarios that given a fixed coordinate of a primary receiver, the optimal relay deployment significantly outperforms the two conventional approaches, i.e., uniform and random topologies.
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| 7. |
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| 8. |
- Beilina, Larisa, 1970, et al.
(författare)
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Globally convergent and adaptive finite element methods in imaging of buried objects from experimental backscattering radar measurements
- 2015
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Ingår i: Journal of Computational and Applied Mathematics. - : Elsevier BV. - 0377-0427. ; 289, s. 371-391
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Tidskriftsartikel (refereegranskat)abstract
- We consider a two-stage numerical procedure for imaging of objects buried in dry sand using time-dependent backscattering experimental radar measurements. These measurements are generated by a single point source of electric pulses and are collected using a microwave scattering facility which was built at the University of North Carolina at Charlotte. Our imaging problem is formulated as the inverse problem of the reconstruction of the spatially distributed dielectric constant, which is an unknown coefficient in Maxwell’s equations.
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| 9. |
- Beilina, Larisa, 1970, et al.
(författare)
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Methods of quantitative reconstruction of shapes and refractive indices from experimental data
- 2015
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Ingår i: Inverse Problems and Applications; (papers from: 3rd Annual Workshop on Inverse Problems, 2013; Stockholm; Sweden; 2 - 6 May 2013); (Proceedings in Mathematics & Statistics). - Cham : Springer International Publishing. - 2194-1009 .- 2194-1017. - 9783319124988 ; 120, s. 13-41
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Konferensbidrag (refereegranskat)abstract
- In this chapter we summarize results of [5, 6, 14] and present new results of reconstruction of refractive indices and shapes of objects placed in the air from blind backscattered experimental data using two-stage numerical procedure of [4]. Data are collected using a microwave scattering facility which was built at the University of North Carolina at Charlotte. On the first stage the approximately globally convergent method of [4] is applied to get a good first approximation for the exact solution. Results of this stage are presented in [5, 14]. On the second stage the local adaptive finite element method of [1] is applied to refine the solution obtained on the first stage. In this chapter we briefly describe methods and present new results for both stages.
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| 10. |
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