| 1. |
- Ahsan, Hajra, et al.
(författare)
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Photocatalysis and adsorption kinetics of azo dyes by nanoparticles of nickel oxide and copper oxide and their nanocomposite in an aqueous medium
- 2022
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Ingår i: PeerJ. - : PeerJ. - 2167-8359. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Azo dyes are recalcitrant organic pollutants present in textile industry effluents. Conventional treatment methods to remove them come with a range of disadvantages. Nanoparticles and their nanocomposites offer more efficient, less expensive and easy to handle wastewater treatment alternative. Methods. In this study, nanoparticles of nickel oxide (NiO-NPs), copper oxide (CuO-NPs) and their nanocomposite (NiO/CuO-NC) were synthesized using co- precipitation method. The functional groups present on the surface of synthesized nanomaterials were verified using Fourier-transform infrared spectroscopy (FTIR). Surface morphology was assessed using scanning electron microscopy (SEM) whereas purity, shape and size of the crystallite were determined using X-ray diffraction (XRD) technique. The potential of these nanomaterials to degrade three dyes i.e., Reactive Red-2 (RR-2), Reactive Black-5 (RB-5) and Orange II sodium salt (OII) azo dyes, was determined in an aqueous medium under visible light (photocatalysis). The photodegradation effectiveness of all nanomaterials was evaluated under different factors like nanomaterial dose (0.02-0.1 g 10 mL-1), concentration of dyes (20-100 mg L-1), and irradiation time (60-120 min). They were also assessed for their potential to adsorb RR-2 and OII dyes. Results. Results revealed that at optimum concentration (60 mgL-1) of RR-2, RB-5, and OII dyes, NiO-NPs degraded 90, 82 and 83%, CuO-NPs degraded 49, 34, and 44%, whereas the nanocomposite NiO/CuO-NC degraded 92, 93, and 96% of the said dyes respectively. The nanomaterials were categorized as the efficient degraders of the dyes in the order: NiO/CuO-NC > NiO-NPs > CuO-NPs. The highest degradation potential shown by the nanocomposite was attributed to its large surface area, small particles size, and quick reactions which were proved by advance analytical techniques. The equilibrium and kinetic adsorption of RR-2 and OII on NiO-NPs, CuO-NPs, and NiO/CuO-NC were well explained with Langmuir and Pseudo second order model, respectively (R2 ≥0.96). The maximum RR-2 adsorption (103 mg/g) was obtained with NiO/CuO-NC. It is concluded that nanocomposites are more efficient and promising for the dyes degradation from industrial wastewater as compared with dyes adsorption onto individual NPs. Thus, the nanocomposite NiO/CuO-NC can be an excellent candidate for photodegradation as well as the adsorption of the dyes in aqueous media.
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| 2. |
- Naqvi, Salman Raza, et al.
(författare)
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Agro-industrial residue gasification feasibility in captive power plants : A South-Asian case study
- 2021
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Ingår i: Energy. - : Elsevier. - 0360-5442 .- 1873-6785. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study is to build knowledge on the potential of agro-industrial residue gasification (AIRG) for use in captive power generation through a comprehensive case study. In order to evaluate the economic viability, key performance indicators, such as net present value (NPV), levelized cost of electricity (LCOE), and operating costs etc. are studied. The major textile industry located in the Raiwind area of Punjab province of Pakistan has been selected. The effect and variations of the capacity factor has also been studied coupled with the levelized cost of electricity. The agricultural residue as feedstock to the gasifier is rice husk that is the abundantly available in South Asia. Furthermore, the impact of government subsidies on natural gas is also under the scope of the study. The agro-industrial residue gasification system is found to be a potential alternative to furnace oil (FO) or gas-based captive power plants (CPPs). The results of residue-based gasification system imply a large potential when comparing the cost of electricity with national grid electricity during the peak hours. Therefore, the proposed gasification system offers economic incentives when the textile industry potentially utilizes gasification-based electricity during peak hours and national grid electricity during off-peak hours. (C) 2020 Elsevier Ltd. All rights reserved.
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| 3. |
- Naqvi, Salman Raza, et al.
(författare)
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Potential of biomass for bioenergy in Pakistan based on present case and future perspectives
- 2018
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 81:1, s. 1247-1258
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Forskningsöversikt (refereegranskat)abstract
- Future energy security and environmental issues are major driving forces for increased biomass utilization globally and especially in developing countries like Pakistan. For efficient utilization of indigenous biomass resources in the future energy mix, it is important to gain knowledge of current energy system in various sectors. Some of the technologies and initiatives are under development to achieve transition from non-renewable resources to renewable resources, and reducing fossil fuel dependency and greenhouse gas emissions. Recently, number of proposals has been presented for the development of sustainable biofuels production methods for promise for accelerating a shift away from an unsustainable approach to possible sustainable production practices or a sustainable social, economic and environment. This article presents an extensive literature review of the biomass-based renewable energy potential in Pakistan based on current energy scenario and future perspectives. It also highlights the availability of the indigenous and local biomass resources and potential biomass conversion technologies to convert such resources to bioenergy. The drivers for utilization of indigenous biomass resources in future energy mix and challenges regarding awareness among stakeholders and R & D to fill knowledge gaps are economically restraints. The article concludes with suggestions on future directions and policies for effective implementation of biomass based renewable energy production.
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| 4. |
- Shakoor, Awais, et al.
(författare)
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A global meta-analysis of greenhouse gases emission and crop yield under no-tillage as compared to conventional tillage
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697.
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Tidskriftsartikel (refereegranskat)abstract
- No-tillage (NT) practice is extensively adopted with aims to improve soil physical conditions, carbon (C) sequestration and to alleviate greenhouse gases (GHGs) emissions without compromising crop yield. However, the influences of NT on GHGs emissions and crop yields remains inconsistent. A global meta-analysis was performed by using fifty peer-reviewed publications to assess the effectiveness of soil physicochemical properties, nitrogen (N) fertilization, type and duration of crop, water management and climatic zones on GHGs emissions and crop yields under NT compared to conventional tillage (CT) practices. The outcome reveals that compared to CT, NT increased CO2, N2O, and CH4 emissions by 7.1, 12.0, and 20.8%, respectively. In contrast, NT caused up to 7.6% decline in global warming potential as compared to CT. However, absence of difference in crop yield was observed both under NT and CT practices. Increasing N fertilization rates under NT improved crop yield and GHGs emission up to 23 and 58%, respectively, compared to CT. Further, NT practices caused an increase of 16.1% CO2 and 14.7% N2O emission in the rainfed areas and up to 54.0% CH4 emission under irrigated areas as compared to CT practices. This meta-analysis study provides a scientific basis for evaluating the effects of NT on GHGs emissions and crop yields, and also provides basic information to mitigate the GHGs emissions that are associated with NT practice.
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| 5. |
- Munir, M. Adeel, et al.
(författare)
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Blockchain Adoption for Sustainable Supply Chain Management : Economic, Environmental, and Social Perspectives
- 2022
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Ingår i: Frontiers in Energy Research. - : Frontiers Media S.A.. - 2296-598X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Due to the rapid increase in environmental degradation and depletion of natural resources, the focus of researchers is shifted from economic to socio-environmental problems. Blockchain is a disruptive technology that has the potential to restructure the entire supply chain for sustainable practices. Blockchain is a distributed ledger that provides a digital database for recording all the transactions of the supply chain. The main purpose of this research is to explore the literature relevant to blockchain for sustainable supply chain management. The focus of this review is on the sustainability of the blockchain-based supply chain concerning environmental conservation, social equality, and governance effectiveness. Using a systematic literature review, a total of 136 articles were evaluated and categorized according to the triple bottom-line aspects of sustainability. Challenges and barriers during blockchain adoption in different industrial sectors such as aviation, shipping, agriculture and food, manufacturing, automotive, pharmaceutical, and textile industries were critically examined. This study has not only explored the economic, environmental, and social impacts of blockchain but also highlighted the emerging trends in a circular supply chain with current developments of advanced technologies along with their critical success factors. Furthermore, research areas and gaps in the existing research are discussed, and future research directions are suggested. The findings of this study show that blockchain has the potential to revolutionize the entire supply chain from a sustainability perspective. Blockchain will not only improve the economic sustainability of the supply chain through effective traceability, enhanced visibility through information sharing, transparency in processes, and decentralization of the entire structure but also will help in achieving environmental and social sustainability through resource efficiency, accountability, smart contracts, trust development, and fraud prevention. The study will be helpful for managers and practitioners to understand the procedure of blockchain adoption and to increase the probability of its successful implementation to develop a sustainable supply chain network.
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| 6. |
- Naqvi, Salman Raza, et al.
(författare)
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Recent developments on sewage sludge pyrolysis and its kinetics : Resources recovery, thermogravimetric platforms, and innovative prospects
- 2021
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Ingår i: Computers and Chemical Engineering. - : Elsevier. - 0098-1354 .- 1873-4375. ; 150
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Tidskriftsartikel (refereegranskat)abstract
- Sewage sludge is a by-product of the wastewater treatment process, which has the potential to be a source of transport fuels, heat, and power using the pyrolysis process. Considering the prevalence and disposal issues associated with sewage sludge, the objective of this study is to critically review the recent advancements in sewage sludge pyrolysis and its kinetics obtained using the thermogravimetric techniques, and other associated different kinetic models documented in the literature. The study will identify optimum operating conditions and design parameters to obtain high yields. The state-of-the-art perspectives and the challenges associated with full-scale implementation are highlighted for biofuels and resource recovery from the sewage sludge. Furthermore, machine-learning approaches in thermal kinetics of pyrolysis are presented and discussed in terms of their effectiveness in predicting thermal kinetics data. Finally, the challenges for a successful implementation and commercial viability of sewage sludge pyrolysis are discussed.
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| 7. |
- Abdal, Noman, et al.
(författare)
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Salinity mitigates cadmium-induced phytotoxicity in quinoa (Chenopodium quinoa Willd.) by limiting the Cd uptake and improved responses to oxidative stress : implications for phytoremediation
- 2023
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Ingår i: Environmental Geochemistry and Health. - : Springer Science and Business Media LLC. - 0269-4042 .- 1573-2983. ; 45:1, s. 171-185
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Tidskriftsartikel (refereegranskat)abstract
- Cadmium (Cd) contamination and soil salinity are the main environmental issues reducing crop productivity. This study aimed to examine the combined effects of salinity (NaCl) and Cd on the physiological and biochemical attributes of quinoa (Chenopodium quinoa Willd.). For this purpose, 30-day-old plants of quinoa genotype “Puno” were transplanted in Hoagland's nutrient solution containing diverse concentrations of Cd: 0, 50, 100, 200 µM Cd, and salinity: 0, 150, and 300 mM NaCl. Results demonstrated that plant growth, stomatal conductance, and pigment contents were significantly lower at all Cd concentrations than the control plants. Quinoa plants exhibited improved growth and tolerance against Cd when grown at a lower level of salinity (150 mM NaCl) combined with Cd. In contrast, the elevated concentration of salinity (300 mM NaCl) combined with Cd reduced shoot and root growth of experimental plants more than 50%. Combined application of salinity and Cd increased Na (25-fold), while lessened the Cd (twofold) and K (1.5-fold) uptake. A blend of high concentrations of Na and Cd caused overproduction of H2O2 (eightfold higher than control) contents and triggered lipid peroxidation. The activities of antioxidant enzymes: ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) were 13, 12, 7 and ninefold higher than control to mitigate the oxidative stress. Due to restricted root to shoot translocation, and greater tolerance potential against Cd, the quinoa genotype, Puno, is suitable for phytostabilization of Cd in saline soils.
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| 8. |
- Ahmad, Bashir, et al.
(författare)
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Effect of Salicylic Acid and Amino Acid on Pea Plant (Pisum sativum) Late Season, Growth and Production
- 2023
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Ingår i: Polish Journal of Environmental Studies. - : HARD Publishing Company. - 1230-1485 .- 2083-5906. ; 32:3, s. 1987-1994
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Tidskriftsartikel (refereegranskat)abstract
- Salicylic acid and amino acid are plant growth promoters. Therefore, the study entitled "Effect of salicylic acid and amino acid on late season peas growth and production" was conducted. The study has two factors: amino acid (Glycine) and salicylic acid each having four levels that were sprayed on peas. Analysis of data showed that maximum germination percentage (92.50 %), plant height (63.16 cm), primary branches plant-1 (2.80), leaves plant-1 (264.27), leaf chlorophyll content (57.25 SPAD), pods plant-1 (49.25), seeds pod-1 (10.41), pod length (11.74 cm) and yield ha-1 (1922.5 kg) having least days to flowering and pod formation (50.13 and 5.12 days) were noted in 225 mg L-1 amino acid. Salicylic acid levels showed that maximum germination percentage (95.83 %) height of plants (71.85 cm), leaves plant-1 (257.13), primary branches plant-1 (3.25), leaf chlorophyll content (55.81 SPAD), pods plant-1 (52.16), seeds pod-1 (10.91), pod length(11.05 cm) and yield ha-1 (1895.0 kg) having least days to pod formation and flowering (5.26 and 48.30 days) were noted in salicylic acid level of 300 mg L-1. The combined effect of 225 mg L-1 amino acid and 300 mg L-1salicylic acid levels positively improved primary branches plant-1 (3.93), pod plant-1 (66.33), pod length (13.77 cm), seeds pod-1 (12.44), leaf chlorophyll content (64.49 SPAD) and maximum yield ha-1 (1942.66 kg). It is concluded that for higher growth and yield pea cultivar Climax when cultivated late could be applied with 225 mg L-1 amino acid and 300 mg L-1 salicylic under Peshawar climatic conditions.
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| 9. |
- Irshad, Muneeb, et al.
(författare)
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Evaluation of BaZr0.8X0.2 (X= Y, Gd, Sm) proton conducting electrolytes sintered at low temperature for IT-SOFC synthesized by cost effective combustion method
- 2020
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 815
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Tidskriftsartikel (refereegranskat)abstract
- In present work, perovskite structured proton conducting electrolyte materials BaZr0.8Y0.2 (BZY), BaZr0.8Gd0.2 (BZGd) and BaZr0.8Sm0.2 (BZSm) synthesized by cost effective combustion method are investigated for intermediate temperature solid oxide fuel cell (IT-SOFC). The synthesized BZY, BZGd and BZSm materials are sintered at low temperature (1150 degrees C) and the effect of low sintering temperature on electrolyte properties are also explored. Microstructure, surface morphology, elemental composition, functional group and weight loss are studied using different characterization techniques like XRD, SEM, EDX, FTIR and TGA. XRD shows cubic perovskite structure of all synthesized materials. Secondary phase of Y2O3 is observed in BZY while BaO is observed in BZGd and BZSm due to low sintering temperature. SEM micrographs reveals dense microstructure of BZSm compared to BZY and BZGd. EDX analysis confirms the required material composition within all samples with no impurities. FTIR shows the presence of hydroxyl group and metal oxides and it is observed that BZY exhibit more structural symmetry compared to BZSm and BZGd. Highest conductivity observed (2.2 x 10(-3) S/cm) for BZY due to its structural symmetry and characteristic to prefer B-site of perovskite. Also significant power densities of 0.34 Wcm(-2), 0.24 Wcm(-2) and 0.32 Wcm(-2) for BZY, BZGd and BZSm electrolytes based cells at 650 degrees C implies that BZY, BZGd and BZSm can be used as IT-SOFC electrolytes. (C) 2019 Elsevier B.V. All rights reserved.
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| 10. |
- Khraief, Naceur, et al.
(författare)
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Are unemployment rates in OECD countries stationary? Evidence from univariate and panel unit root tests
- 2020
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Ingår i: The North American journal of economics and finance. - : Elsevier. - 1062-9408 .- 1879-0860. ; 51
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Tidskriftsartikel (refereegranskat)abstract
- This paper revisits the dynamics of unemployment rate for 29 OECD countries over the period of 1980–2013. Numerous empirical studies of the dynamics of unemployment rate are carried out within a linear framework. However, unemployment rate can show nonlinear behaviour as a result of business cycles or some idiosyncratic factors specific to labour market (Cancelo, 2007). Thus, as a testing strategy, we first perform Harvey, Leybourne, and Xiao (2008) linearity unit root test and then apply the newly ESTAR nonlinear unit root test suggested by Kruse (2011). This test has higher power than conventional unit root tests when time series exhibits nonlinear behaviour. Our empirical findings provide significant evidence in favour of unemployment rate stationarity for 25 countries. For robustness purpose, we have also used panel unit root tests without and with structural breaks. The empirical results show that unemployment hysteresis hypothesis is strongly rejected, when taking into account the cross-sectional and structural break assumptions. Thus, unemployment rate is expected to return back to their natural levels without executing any costly macroeconomic labour market policies by the OECD's governments.
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| 11. |
- Naqvi, Salman Raza, et al.
(författare)
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Pyrolysis of high ash sewage sludge : Kinetics and thermodynamic analysis using Coats-Redfern method
- 2019
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Ingår i: Renewable energy. - : Elsevier Ltd. - 0960-1481 .- 1879-0682. ; 131, s. 854-860
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Tidskriftsartikel (refereegranskat)abstract
- This study aims to investigate the thermo-kinetics of high-ash sewage sludge using thermogravimetric analysis. Sewage sludge was dried, pulverized and heated non-isothermally from 25 to 800 °C at different heating rates (5, 10 and 20 °C/min) in N2 atmosphere. TG and DTG results indicate that the sewage sludge pyrolysis may be divided into three stages. Coats-Redfern integral method was applied in the 2nd and 3rd stage to estimate the activation energy and pre-exponential factor from mass loss data using five major reaction mechanisms. The low-temperature stable components (LTSC) of the sewage sludge degraded in the temperature regime of 250–450 °C while high-temperature stable components (HTSC) decomposed in the temperature range of 450–700 °C. According to the results, first-order reaction model (F1) showed higher Ea with better R2 for all heating rates. D3, N1, and S1 produced higher Ea at higher heating rates for LTSC pyrolysis and lower Ea with the increase of heating rates for HTSC pyrolysis. All models showed positive ΔH except F1.5. Among all models, Diffusion (D1, D2, D3) and phase interfacial models (S1, S2) showed higher ΔG as compared to reaction, nucleation, and power-law models in section I and section II.
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| 12. |
- Pang, Yanwei, et al.
(författare)
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Mask-Guided Attention Network for Occluded Pedestrian Detection
- 2019
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Ingår i: 2019 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION (ICCV 2019). - : IEEE COMPUTER SOC. - 9781728148038 ; , s. 4966-4974
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Konferensbidrag (refereegranskat)abstract
- Pedestrian detection relying on deep convolution neural networks has made significant progress. Though promising results have been achieved on standard pedestrians, the performance on heavily occluded pedestrians remains far from satisfactory. The main culprits are intra-class occlusions involving other pedestrians and inter-class occlusions caused by other objects, such as cars and bicycles. These result in a multitude of occlusion patterns. We propose an approach for occluded pedestrian detection with the following contributions. First, we introduce a novel mask-guided attention network that fits naturally into popular pedestrian detection pipelines. Our attention network emphasizes on visible pedestrian regions while suppressing the occluded ones by modulating full body features. Second, we empirically demonstrate that coarse-level segmentation annotations provide reasonable approximation to their dense pixel-wise counterparts. Experiments are performed on CityPersons and Caltech datasets. Our approach sets a new state-of-the-art on both datasets. Our approach obtains an absolute gain of 9.5% in log-average miss rate, compared to the best reported results [31] on the heavily occluded HO pedestrian set of CityPersons test set. Further, on the HO pedestrian set of Caltech dataset, our method achieves an absolute gain of 5.0% in log-average miss rate, compared to the best reported results [13]. Code and models are available at: https://github.com/Leotju/MGAN.
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| 13. |
- Ahmed, Shahbaz, et al.
(författare)
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Accurate First-Principles Evaluation of Structural, Electronic, Optical and Photocatalytic Properties of BaHfO3 and SrHfO3 Perovskites
- 2022
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Ingår i: Journal of Alloys and Compounds. - : Elsevier. - 0925-8388 .- 1873-4669. ; 892
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Tidskriftsartikel (refereegranskat)abstract
- A reliable first-principles account of experimentally observed physical properties of perovskite oxides is crucial for realizing their employment in electronic and optical devices. In this context, SCAN meta-GGA functional of DFT offers good approximation for the exchange-correlation energy; facilitating accurate determination of structural and energetic properties. However, SCAN is unable to reproduce electronic and optical properties of wide bad gap materials. In the present study, we report systematic DFT calculations to show that structural, energetic, electronic and optical properties of hafnium based BaHfO3 and SrHfO3 perovskite oxides can be accurately determined through a combine application of SCAN and Tran-Blaha modified Becke-Johnson (TB-mBJ) meta-GGAs. The structural and energetic properties computed using SCAN functional for both BaHfO3 and SrHfO3 are found to be in good agreement with experimental data; achieving a level of accuracy comparable to computationally expansive hybrid DFT calculations. On the other hand, TB-mBJ calculated band gaps computed using the SCAN optimized lattice parameters provide better agreement with experimental data at a low computational cost. The optical properties, band edge potentials and effective masses of the charge carriers in BaHfO3 and SrHfO3 are also computed to examine the combined application of SCAN and TB-mBJ meta-GGAs in predicting the photocatalytic performance of these wide band gap materials. Our results clearly show that the combination of the two meta-GGAs provide a computationally economical route for evaluating the photocatalytic performance of alkaline-earth metal hafnates.
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| 14. |
- Bhunia, Ankan Kumar, et al.
(författare)
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Handwriting Transformers
- 2021
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Ingår i: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION (ICCV 2021). - : IEEE. - 9781665428125 - 9781665428132 ; , s. 1066-1074
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We propose a novel transformer-based styled handwritten text image generation approach, HWT, that strives to learn both style-content entanglement as well as global and local writing style patterns. The proposed HWT captures the long and short range relationships within the style examples through a self-attention mechanism, thereby encoding both global and local style patterns. Further, the proposed transformer-based HWT comprises an encoder-decoder attention that enables style-content entanglement by gathering the style representation of each query character. To the best of our knowledge, we are the first to introduce a transformer-based generative network for styled handwritten text generation. Our proposed HWT generates realistic styled handwritten text images and significantly outperforms the state-of-the-art demonstrated through extensive qualitative, quantitative and human-based evaluations. The proposed HWT can handle arbitrary length of text and any desired writing style in a few-shot setting. Further, our HWT generalizes well to the challenging scenario where both words and writing style are unseen during training, generating realistic styled handwritten text images.
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| 15. |
- Cai, Guan, et al.
(författare)
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Root exudates with low C/N ratios accelerate CO2 emissions from paddy soil
- 2022
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Ingår i: Land Degradation and Development. - : Wiley. - 1099-145X .- 1085-3278. ; 33:8, s. 1193-1203
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Tidskriftsartikel (refereegranskat)abstract
- Root exudates can significantly modify microbial activity and soil organic matter (SOM) mineralization. However, how root exudates and their C/N stoichiometric ratios control paddy soil C mineralization is poorly understood. This study used a mixture of glucose, oxalic acid, and alanine as root exudate mimics for three C/N stoichiometric ratios (CN6, CN10, and CN80) to explore the underlying mechanisms involved in SOM mineralization. The input of root exudates enhanced CO2 emissions by 1.8–2.3-fold that of soil with only C additions (C-only). Artificial root exudates with low C/N ratios (CN6 and CN10) increased the metabolic quotient (qCO2) by 12% over those with higher stoichiometric ratios (CN80 and C-only), suggesting a relatively high energy demand for microorganisms to acquire organic N from SOM by increasing N-hydrolase production. The increase of stoichiometric ratios of C- to N-hydrolase (β-1,4-glucosidase to β-1,4-N-acetyl glucosaminidase) promoted SOM degradation compared to those involved in organic C- and N- degradation, which had a significant positive correlation with qCO2. The stoichiometric ratios of microbial biomass (MBC/MBN) were positively correlated with C use efficiency, indicating root exudates with higher C/N ratios provide an undersupply of N for microorganisms that trigger the release of N-degrading extracellular enzymes. Our findings showed that the C/N stoichiometry of root exudates controlled SOM mineralization by affecting the specific response of the microbial biomass through the activity of C- and N-releasing extracellular enzymes to adjust the microbial C/N ratio.
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| 16. |
- Cao, Jiale, et al.
(författare)
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SipMaskv2: Enhanced Fast Image and Video Instance Segmentation
- 2023
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Ingår i: IEEE Transactions on Pattern Analysis and Machine Intelligence. - : IEEE. - 0162-8828 .- 1939-3539 .- 2160-9292. ; 45:3, s. 3798-3812
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Tidskriftsartikel (refereegranskat)abstract
- We propose a fast single-stage method for both image and video instance segmentation, called SipMask, that preserves the instance spatial information by performing multiple sub-region mask predictions. The main module in our method is a light-weight spatial preservation (SP) module that generates a separate set of spatial coefficients for the sub-regions within a bounding-box, enabling a better delineation of spatially adjacent instances. To better correlate mask prediction with object detection, we further propose a mask alignment weighting loss and a feature alignment scheme. In addition, we identify two issues that impede the performance of single-stage instance segmentation and introduce two modules, including a sample selection scheme and an instance refinement module, to address these two issues. Experiments are performed on both image instance segmentation dataset MS COCO and video instance segmentation dataset YouTube-VIS. On MS COCO test-dev set, our method achieves a state-of-the-art performance. In terms of real-time capabilities, it outperforms YOLACT by a gain of 3.0% (mask AP) under the similar settings, while operating at a comparable speed. On YouTube-VIS validation set, our method also achieves promising results. The source code is available at https://github.com/JialeCao001/SipMask.
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| 17. |
- Heshmati, Almas, et al.
(författare)
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Hiring and separation rates before and after the Arab Spring in the Tunisian labor market
- 2017
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Ingår i: South African Journal of Economics. - : John Wiley & Sons. - 0038-2280 .- 1813-6982. ; 85:2, s. 259-278
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Tidskriftsartikel (refereegranskat)abstract
- We seek to explore the hiring and separation rates in Tunisia before and after the Arab Spring based on quarterly business level data for 503 firms over the span of January 2007 to December 2012. Furthermore, we examine whether employers are willing to dismiss older workers to trigger an effective increase in mobility that will open new opportunities for the youth community. We build our analysis upon six main empirical models to study employment decisions reflected by major indicators such as the number of hiring, number of separations, total employment effects, male-female ratio, age cohorts, labour mobility and net employment. The results show that the Arab Spring has created structural unemployment trends. In addition, we note that the 2008 global turmoil has fostered the firing level of employment. Our conclusions also indicate that the response of Tunisia's government to high unemployment rates caused by the financial meltdown in 2008 and the events in 2011 was not sufficient to remove the attached lingering effects that still distress the country's labour market. In addition, our findings emphasize the significant challenges faced by Tunisian youth that could be mitigated by efficient policy actions to incentivize training and development geared towards the private sector.
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| 18. |
- Jia, Rong, et al.
(författare)
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Insights into the associations between soil quality and ecosystem multifunctionality driven by fertilization management : A case study from the North China Plain
- 2022
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 362
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Tidskriftsartikel (refereegranskat)abstract
- Recycling of livestock manure in agroecosystems has been shown to enhance the sustainability of food production and reduce adverse environmental consequences from intensive crop-livestock systems. However, the effect of manure application on the associations between soil quality and ecosystem multifunctionality still remains poorly understood. Hereby, we used a five-year field experiment to investigate the effect of mineral and manure fertilization on soil quality, enzymatic stoichiometry, and ecosystem multifunctionality for both topsoil and subsoil (i.e. 0-20 cm and 20–40 cm). Manure alone and combined with mineral fertilization increased soil quality index by 49.5 and 70.1% in the topsoil, and by 67.5% and 26.6% in subsoil compared to no fertilization. Moreover, the manure application increased the C, N, and P acquisition enzyme activities, especially those for C and P cycling. Fertilization regimes affect enzymatic stoichiometry in subsoil rather than topsoil. Manure application increased soil ecosystem multifunctionality in both top and subsoil by 2.1 and 0.4 times, respectively. Interestingly, the soil quality was positively correlated with ecosystem multifunctionality regardless of fertilization regimes. Furthermore, random forest analysis showed that soil organic C and N content, available P, and microbial biomass were the main drivers of soil ecosystem multifunctionality. Conversely, mineral fertilization did not affect soil quality and enzyme activity in both soil layers, and thus did not change soil ecosystem multifunctionality. In conclusion, manure application fosters soil quality and has the potential to improve the soil multifunctionality, thereby providing an effective way to sustainable soil management and cleaner crop production.
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| 19. |
- Jiang, Yonglei, et al.
(författare)
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Rotation cropping and organic fertilizer jointly promote soil health and crop production
- 2022
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797. ; 315
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Tidskriftsartikel (refereegranskat)abstract
- Identifying field management practices to promote crop production, while conserving soil health is essential to maintain long-term food production in a changing world. Also, providing experimental evidence to support the use of traditional agricultural practices is necessary to secure sustainable agriculture. Here, we conducted a long-term 12-year experiment to investigate the impact of different combinations of fertilization type (control, inorganic fertilizer, organic fertilizer) and cropping regimes (continuous cropping and rotation cropping) on the crop (tobacco) production and multiple soil attributes associated with soil health, including proportions of soil-borne pathogens and decomposers, soil microbial diversity, microbial network stability and biomass, nutrient pools and microbial resource limitations. Our long-term experiment supports that the combination of organic fertilizer with rotation cropping increased crop production by at least 40% compared to the other management combinations and improved soil nutrient pools (e.g. the content of soil organic matter), improved the relative proportion of soil decomposers, and promoted bacterial and fungal network stability and biodiversity. Furthermore, this combination treatment relieved microbial resource limitation and reduced the abundance of potential fungal plant pathogens by at least 20% compared to other management combinations. In summary, we provide experimental evidence to support that the combined use of organic fertilization and rotation cropping management can help maintain long-term soil health, crop production, and economic outputs.
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| 20. |
- Kahlert, Maria, et al.
(författare)
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New molecular methods to assess biodiversity. Potentials and pitfalls of DNA metabarcoding: a workshop report
- 2019
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Ingår i: Research Ideas and Outcomes. - : Pensoft Publishers. - 2367-7163. ; 5
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This report presents the outcome of the joint work of PhD students and senior researchers working with DNA-based biodiversity assessment approaches with the goal to facilitate others the access to definitions and explanations about novel DNA-based methods. The work was performed during a PhD course (SLU PNS0169) at the Swedish University of Agricultural Sciences (SLU) in Uppsala, Sweden. The course was co-organized by the EU COST research network DNAqua-Net and the SLU Research Schools Focus on Soils and Water (FoSW) and Ecology - basics and applications. DNAqua-Net (COST Action CA15219, 2016-2020) is a network connecting researchers, water managers, politicians and other stakeholders with the aim to develop new genetic tools for bioassessment of aquatic ecosystems in Europe and beyond. The PhD course offered a comprehensive overview of the paradigm shift from traditional morphology-based species identification to novel identification approaches based on molecular markers. We covered the use of molecular tools in both basic research and applied use with a focus on aquatic ecosystem assessment, from species collection to the use of diversity in environmental legislation. The focus of the course was on DNA (meta)barcoding and aquatic organisms. The knowledge gained was shared with the general public by creating Wikipedia pages and through this collaborative Open Access publication, co-authored by all course participants.
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| 21. |
- Khan, Fahad Shahbaz, et al.
(författare)
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Color Attributes for Object Detection
- 2012
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Ingår i: Proceedings of IEEE Conference on Computer Vision and Pattern Recognition (CVPR) 2012. - : IEEE. - 9781467312271 - 9781467312264 ; , s. 3306-3313
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Konferensbidrag (refereegranskat)abstract
- State-of-the-art object detectors typically use shape information as a low level feature representation to capture the local structure of an object. This paper shows that early fusion of shape and color, as is popular in image classification, leads to a significant drop in performance for object detection. Moreover, such approaches also yields suboptimal results for object categories with varying importance of color and shape. In this paper we propose the use of color attributes as an explicit color representation for object detection. Color attributes are compact, computationally efficient, and when combined with traditional shape features provide state-of-the-art results for object detection. Our method is tested on the PASCAL VOC 2007 and 2009 datasets and results clearly show that our method improves over state-of-the-art techniques despite its simplicity. We also introduce a new dataset consisting of cartoon character images in which color plays a pivotal role. On this dataset, our approach yields a significant gain of 14% in mean AP over conventional state-of-the-art methods.
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| 22. |
- Khan, Fahad Shahbaz, 1983-, et al.
(författare)
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Coloring Action Recognition in Still Images
- 2013
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Ingår i: International Journal of Computer Vision. - : Springer Science and Business Media LLC. - 0920-5691 .- 1573-1405. ; 105:3, s. 205-221
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Tidskriftsartikel (refereegranskat)abstract
- In this article we investigate the problem of human action recognition in static images. By action recognition we intend a class of problems which includes both action classification and action detection (i.e. simultaneous localization and classification). Bag-of-words image representations yield promising results for action classification, and deformable part models perform very well object detection. The representations for action recognition typically use only shape cues and ignore color information. Inspired by the recent success of color in image classification and object detection, we investigate the potential of color for action classification and detection in static images. We perform a comprehensive evaluation of color descriptors and fusion approaches for action recognition. Experiments were conducted on the three datasets most used for benchmarking action recognition in still images: Willow, PASCAL VOC 2010 and Stanford-40. Our experiments demonstrate that incorporating color information considerably improves recognition performance, and that a descriptor based on color names outperforms pure color descriptors. Our experiments demonstrate that late fusion of color and shape information outperforms other approaches on action recognition. Finally, we show that the different color–shape fusion approaches result in complementary information and combining them yields state-of-the-art performance for action classification.
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| 23. |
- Khan, Fahad Shahbaz, et al.
(författare)
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Compact color–texture description for texture classification
- 2015
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Ingår i: Pattern Recognition Letters. - : Elsevier. - 0167-8655 .- 1872-7344. ; 51, s. 16-22
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Tidskriftsartikel (refereegranskat)abstract
- Describing textures is a challenging problem in computer vision and pattern recognition. The classification problem involves assigning a category label to the texture class it belongs to. Several factors such as variations in scale, illumination and viewpoint make the problem of texture description extremely challenging. A variety of histogram based texture representations exists in literature. However, combining multiple texture descriptors and assessing their complementarity is still an open research problem. In this paper, we first show that combining multiple local texture descriptors significantly improves the recognition performance compared to using a single best method alone. This gain in performance is achieved at the cost of high-dimensional final image representation. To counter this problem, we propose to use an information-theoretic compression technique to obtain a compact texture description without any significant loss in accuracy. In addition, we perform a comprehensive evaluation of pure color descriptors, popular in object recognition, for the problem of texture classification. Experiments are performed on four challenging texture datasets namely, KTH-TIPS-2a, KTH-TIPS-2b, FMD and Texture-10. The experiments clearly demonstrate that our proposed compact multi-texture approach outperforms the single best texture method alone. In all cases, discriminative color names outperforms other color features for texture classification. Finally, we show that combining discriminative color names with compact texture representation outperforms state-of-the-art methods by 7.8%,4.3%7.8%,4.3% and 5.0%5.0% on KTH-TIPS-2a, KTH-TIPS-2b and Texture-10 datasets respectively.
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| 24. |
- Khan, Fahad Shabhaz, et al.
(författare)
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Data Mining in Oral Medicine Using Decision Trees
- 2008
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Ingår i: Proceedings of the 5th International Conference on Computer, Electrical, and Systems Science, and Engineering (CESSE 2008), Cairo, Egypt, February 6–8, 2008. - : World Academy of Science Engineering and Technology - WASET. ; 27, s. 225-230
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Konferensbidrag (refereegranskat)abstract
- Data mining has been used very frequently to extract hidden information from large databases. This paper suggests the use of decision trees for continuously extracting the clinical reasoning in the form of medical expert’s actions that is inherent in large number of EMRs (Electronic Medical records). In this way the extracted data could be used to teach students of oral medicine a number of orderly processes for dealing with patients who represent with different problems within the practice context over time.
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| 25. |
- Khan, Fahad Shahbaz, et al.
(författare)
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Deep Semantic Pyramids for Human Attributes and Action Recognition
- 2015
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Ingår i: Image Analysis. - Cham : Springer. - 9783319196657 - 9783319196640 ; , s. 341-353
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Konferensbidrag (refereegranskat)abstract
- Describing persons and their actions is a challenging problem due to variations in pose, scale and viewpoint in real-world images. Recently, semantic pyramids approach [1] for pose normalization has shown to provide excellent results for gender and action recognition. The performance of semantic pyramids approach relies on robust image description and is therefore limited due to the use of shallow local features. In the context of object recognition [2] and object detection [3], convolutional neural networks (CNNs) or deep features have shown to improve the performance over the conventional shallow features.We propose deep semantic pyramids for human attributes and action recognition. The method works by constructing spatial pyramids based on CNNs of different part locations. These pyramids are then combined to obtain a single semantic representation. We validate our approach on the Berkeley and 27 Human Attributes datasets for attributes classification. For action recognition, we perform experiments on two challenging datasets: Willow and PASCAL VOC 2010. The proposed deep semantic pyramids provide a significant gain of 17.2%, 13.9%, 24.3% and 22.6% compared to the standard shallow semantic pyramids on Berkeley, 27 Human Attributes, Willow and PASCAL VOC 2010 datasets respectively. Our results also show that deep semantic pyramids outperform conventional CNNs based on the full bounding box of the person. Finally, we compare our approach with state-of-the-art methods and show a gain in performance compared to best methods in literature.
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