Articles de revues sur le sujet « Adverse scenarios calibration »
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Diep, Anh Nguyet, Jean-Christophe Servotte, Nadia Dardenne, Sophie Vanbelle, Vanessa Wauthier, Méryl Paquay, Suzanne Hetzel Campbell, Jonathan Goffoy, Anne-Françoise Donneau et Alexandre Ghuysen. « The Performance of the Health Communication Assessment Tool© (HCAT-f) in Calibrating Different Levels of Nurse Communication Skills in a French-Speaking Context ». European Journal of Health Communication 3, no 3 (7 décembre 2022) : 164–79. http://dx.doi.org/10.47368/ejhc.2022.308.
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Communication skills training is essential in nurse education. Miscommunication may lead to adverse events and unsafe healthcare. To date, valid and reliable instruments to serve both communication training and assessment purposes across different cultural contexts are scarce. The present study empirically tested a French-language version of the Health Communication Assessment Tool© (HCAT-f) across different levels of communication skills performance to establish its reliability and validity through a cognitive fluency framework. Ten experts in communication and 52 nurse educators rated three videos simulating conversations between a nurse and a patient scheduled for lumpectomy. Each video captured a different level of communication skills performed by the nurse: High, medium, and low. Three distinct constructs were identified, i.e., professional presentation, empathy, and trust building. At absolute single-measure, an ICC = .43 suggested adequate interrater reliability of the whole scale for the medium-performed scenario, which decreased in low-performed (ICC = .35) and high-performed (ICC = .18) scenarios. The HCAT-f fulfils the criteria of linguistic equivalence, contextual relevance, and demonstrates acceptable construct validity. It can be used as a summative assessment tool after prior training on scale calibration is in place because interrater agreement was difficult to be established in high and low performance scenarios.
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Pandey, Ashish, K. C. Bishal, Praveen Kalura, V. M. Chowdary, C. S. Jha et Artemi Cerdà. « A Soil Water Assessment Tool (SWAT) Modeling Approach to Prioritize Soil Conservation Management in River Basin Critical Areas Coupled With Future Climate Scenario Analysis ». Air, Soil and Water Research 14 (janvier 2021) : 117862212110213. http://dx.doi.org/10.1177/11786221211021395.
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About 44% of the Indian landmass experiences the adverse impact of land degradation. This loss of sediments caused by soil erosion reduces the water quality of local water bodies and decreases agricultural land productivity. Therefore, decision-makers must formulate policies and management practices for sustainable management of basins that are cost-effective and environment friendly. Application of the best management practices (BMPs) to properly manage river basins is difficult and time-consuming. Its implication under various climate change scenarios makes it more complicated but necessary to achieve sustainable development. In this study, the soil and water assessment tool (SWAT) model was employed to prioritize the Tons river basin’s critical areas in the central Indian states coupled with future climate scenario analysis (2030–2050) using Representative Concentration Pathway (RCP) 4.5 and RCP 8.5 scenarios. The SWAT model was calibrated and validated for simulation of streamflow and sediment yield for daily and monthly scales using the sequential uncertainty fitting (SUFI-2) technique. The values of coefficient of determination ( R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS), and root mean square error (RMSE)-observations standard deviation ratio (RSR) were .71, .70, −8.3, and .54, respectively during the calibration period, whereas for validation the values were .72, .71, −3.9, and .56, respectively. SWAT model underestimated the discharge during calibration and overestimated the discharge during validation. Model simulations for sediment load exhibited a similar trend as streamflow simulation, where higher values are reported during August and September. The average annual sediment yield of the basin for the baseline period was 6.85 Mg ha−1, which might increase to 8.66 Mg ha−1 and 8.79 Mg ha−1 in the future years 2031–2050 and 2081–2099, respectively. The BMPs such as recharge structure, contour farming, filter strip 3 and 6 m, porous gully plugs, zero tillage, and conservation tillage operations have been considered to evaluate the soil and water conservation measures. Recharge structure appeared to be the most effective measure with a maximum reduction of sediment by 38.98% during the baseline period, and a 37.15% reduction in the future scenario. Sub-watersheds, namely SW-8, SW-10, SW-12, SW-13, SW-14, SW-17, SW-19, SW-21, SW-22, and SW-23, fall under the high category and are thus considered a critical prone area for the implementation and evaluation of BMPs. Compared to the baseline period, the effectiveness of BMPs is slightly decreasing in the 2040s, increasing in the 2070s and decreasing in the 2090s. Recharge structure and filter strip 6 m have been found to nullify the high soil erosion class completely. Overall, SWAT model simulations under the RCP 8.5 scenarios were observed to be reliable and can be adopted to identify critical areas for river basins having similar climatic and geographical conditions.
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Peng, Liang, Hong Wang et Jun Li. « Uncertainty Evaluation of Object Detection Algorithms for Autonomous Vehicles ». Automotive Innovation 4, no 3 (30 juillet 2021) : 241–52. http://dx.doi.org/10.1007/s42154-021-00154-0.
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AbstractThe safety of the intended functionality (SOTIF) has become one of the hottest topics in the field of autonomous driving. However, no testing and evaluating system for SOTIF performance has been proposed yet. Therefore, this paper proposes a framework based on the advanced You Only Look Once (YOLO) algorithm and the mean Average Precision (mAP) method to evaluate the object detection performance of the camera under SOTIF-related scenarios. First, a dataset is established, which contains road images with extreme weather and adverse lighting conditions. Second, the Monte Carlo dropout (MCD) method is used to analyze the uncertainty of the algorithm and draw the uncertainty region of the predicted bounding box. Then, the confidence of the algorithm is calibrated based on uncertainty results so that the average confidence after calibration can better reflect the real accuracy. The uncertainty results and the calibrated confidence are proposed to be used for online risk identification. Finally, the confusion matrix is extended according to the several possible mistakes that the object detection algorithm may make, and then the mAP is calculated as an index for offline evaluation and comparison. This paper offers suggestions to apply the MCD method to complex object detection algorithms and to find the relationship between the uncertainty and the confidence of the algorithm. The experimental results verified by specific SOTIF scenarios proof the feasibility and effectiveness of the proposed uncertainty acquisition approach for object detection algorithm, which provides potential practical implementation chance to address perceptual related SOTIF risk for autonomous vehicles.
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BANERJEE, SAON, KUSHAL SARMAH, ASIS MUKHERJEE, ABDUS SATTAR et PINTOO BANDOPADHYAY. « Effect of projected climate scenarios on the yields of potato crop and agronomic adaptation options as evaluated by crop growth model ». MAUSAM 73, no 1 (15 janvier 2022) : 71–78. http://dx.doi.org/10.54302/mausam.v73i1.5081.
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Potato is the most important non-cereal crop in the world and the most prominent winter season crop in India. Growth and yield of potato crop is very much sensitive to higher temperatures and the moisture stress. Hence, the anticipated increase of temperature due to global warming and climatic variability will have anadverse impact on potato production. Keeping this in view, a research work was carried out with the objectives to assess the impact of climate change on potato production and evaluating agronomic adaptation options through a crop growth simulation model (CGSM). Field experiments were carried out to prepare the minimum dataset for calibration and validation of one CGSM, namely InfoCrop. After validation, the model was used to predict the future tuber yield of ten selected stations situated under different agroclimatic regions of the State. In the future scenario 2050, the simulated yield for mid November planted crop likely to be about 11% less than the present level of mean yield. If the crop is planted in December, the percentage of yield reduction may be around 25%.The projected yield reduction, for the stations of higher latitude, is found to be negligible. Three possible agronomic adaptation options, viz., adjustment of date of planting, increase of seed rate and varying sprout length of seed tubers, have been tried as adaptation strategies to combat the adverse effects of climate change. It is concluded that the mid-November planting and longer sprout length will be the best adaptation option. However, the enhanced seed rate is not a viable adaptation option.
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Xu, Zongxue, et Gang Zhao. « Impact of urbanization on rainfall-runoff processes : case study in the Liangshui River Basin in Beijing, China ». Proceedings of the International Association of Hydrological Sciences 373 (12 mai 2016) : 7–12. http://dx.doi.org/10.5194/piahs-373-7-2016.
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Abstract. China is undergoing rapid urbanization during the past decades. For example, the proportion of urban population in Beijing has increased from 57.6 % in 1980 to 86.3 % in 2013. Rapid urbanization has an adverse impact on the urban rainfall-runoff processes, which may result in the increase of urban flood risk. In the present study, the major purpose is to investigate the impact of land use/cover change on hydrological processes. The intensive human activities, such as the increase of impervious area, changes of river network morphology, construction of drainage system and water transfer, were considered in this study. Landsat TM images were adopted to monitor urbanization process based on Urban Land-use Index (ULI). The SWMM model considering different urbanized scenarios and anthropogenic disturbance was developed. The measured streamflow data was used for model calibration and validation. Precipitation with different return periods was taken as model input to analyse the changes of flood characteristics under different urbanized scenarios. The results indicated that SWMM provided a good estimation for storms under different urbanized scenarios. The volume of surface runoff after urbanization was 3.5 times greater than that before urbanization; the coefficient of runoff changed from 0.12 to 0.41, and the ratio of infiltration decreased from 88 to 60 %. After urbanization, the time of overland flow concentration increased while the time of river concentration decreased; the peak time did not show much difference in this study. It was found that the peak flow of 20-year return-period after urbanization is greater than that of 100-year return-period before urbanization. The amplification effect of urbanization on flood is significant, resulting in an increase of the flooding risk. These effects are especially noticeable for extreme precipitation. The results in this study will provide technical support for the planning and management of urban storm water and the evaluation on Low Impact Development (LID) measures.
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Szarka, Nora, Jürgen Wolfbauer et Alberto Bezama. « A systems dynamics approach for supporting regional decisions on the energetic use of regional biomass residues ». Waste Management & ; Research : The Journal for a Sustainable Circular Economy 36, no 4 (23 février 2018) : 332–41. http://dx.doi.org/10.1177/0734242x18757626.
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This article presents the definition, building, calibration and application of a system dynamics simulation model to quantify the present and future comparative advantages and disadvantages of using forest and agricultural residual biomass for energetic purpose through different processes and technologies, on a regional basis. A dynamic structure of the agricultural and forestry biomass process activities (i.e. production, transport, conversion and consumption) based on regional time-series data was built, implemented into and calibrated within a dynamic simulation tool (Vensim software) within a Hungarian county. Besides the agriculture and forestry sectors, the model includes data about demography, economy, environment and land use, among others. For carrying out the assessment, realistic scenarios of future biomass processes and of biomass use were formulated, characterised by quantitative sustainable development indicators and simulated within the dynamic model. The results prove that the introduced model supports decision making of biomass utilisation in a regional scale, through comparing and analysing quantitative changes of economic, social and environment indicators, which characterise a sustainable regional development. The model therefore allows analyses and evaluation of not only partial prosperous or adverse characteristics of biomass processes and use, but also to relate regional components and their development over time. The developed dynamic tool is therefore a powerful method to model complex systems, such as a regional energy system, considering the framework of the regional preferences stated by the regional stakeholders. It can thus provide useful decision support, especially when used as a priority-based screening of potential regional development programmes in the energy field.
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Hlásny, Tomáš, Dušan Kočický, Martin Maretta, Zuzana Sitková, Ivan Barka, Milan Konôpka et Helena Hlavatá. « Effect of deforestation on watershed water balance : hydrological modelling-based approach / Vplyv odlesnenia na vodnú bilanciu povodia : prístup na báze hydrologického modelovania ». Forestry Journal 61, no 2 (1 juin 2015) : 89–100. http://dx.doi.org/10.1515/forj-2015-0017.
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Abstract Changes in land cover, including deforestation, can have significant effect on watershed hydrology. We used hydrological model with distributed parameters to evaluate the effect of simulated deforestation on water balance components in the watershed Ulička (97 km2, 84.3% forest cover) located in the eastern Slovakia. Under the current land cover, average interception accounted for 21.1% of the total precipitation during the calibration period 2001-2013. Most of the precipitation (77%) infiltrated into the soil profile, and less than half of this amount percolated into the ground water aquifer. The surface runoff accounted for 1.2% of the total precipitation only, while the interflow accounted for ca. 12%. The largest proportion of the precipitation contributed to the base flow (23%). Watershed`s deforestation induced significant decrease in the interception and evapotranspiration (by 76% and 12%, respectively). At the same time, total runoff, surface runoff, interflow and base flow increased by 20.4, 38.8, 9.0 and 25.5%, respectively. Daily discharge increased by 20%. The deforestation significantly increased peak discharge induced by a simulated extreme precipitation event with the recurrence interval of 100 years. In the deforested watershed, the peak discharge was higher by 58% as compared with the current land cover. Peak discharge occurred in 432 minutes with the current land cover and in 378 minutes with deforestation, after the precipitation event had started. The presented assessment emphasized the risk of adverse effect of excessive deforestation on watershed hydrology. At the same time, the developed model allows testing the effect of other land cover scenarios, and thus supports management in the investigated watershed.
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Haddout, Soufiane, Abdelkrim Jamali, Mbarek Rhazi et Mohamed Aghfir. « Finite volume coastal ocean model for water-level fluctuation due to climate change in Aguelmam Sidi Ali Lake (Middle Atlas, Morocco) ». Annales de Limnologie - International Journal of Limnology 54 (2018) : 5. http://dx.doi.org/10.1051/limn/2017033.
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Climate changes are the main motivation for alteration of ecosystems; in fact the effects of these changes on biodiversity and ecosystems are considered as the most challenging cases in present century. Therefore, since the lakes are the most important services and functions of ecosystems, the effect of climate change on water level fluctuations of Aguelmam Sidi Ali Lake (Morocco) was analyzed as a natural ecosystem in this essay. The regular observations from the lake have found that a very sensitive withdrawal of their water level during the dry years. Therefore, a hydrodynamic model has been used to simulate the condition of Aguelmam Sidi Ali Lake, with observed field data (model has been set up to run annually for a total 35 year data, i.e., precipitation, evaporation, runoff discharges and water-level which are available for the last 35 years) being used for model calibration and validation. Additionally, the model validation process showed that the model results fit the observed data fairly well (R2 = 0.70−0.74, root mean square error [RMSE] = 1.63−1.71 m). On the other hand, different hydrological conditions regarding lake input and output data were tested and water depth was calculated using bathymetry to predict water-level fluctuations in the future. The results predict that the water-level will decrease continuously (In 2044, the water level will reach to 6.20 m). The water level decrease due to the climate change in both scenarios (dry and very dry) is dramatic and a profound adverse impact on the environmental balance is predicted in the region. Additionally, the lake will be dried up in about 20 years if very dry conditions continue in the region. This reveals the importance of this type of approach for obtaining a first-order estimate of water-level variations in Sidi Ali Lake, affected by climate change.
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Bhakta, Nickhill, Kalatu Davies, Jesse Turner, Yichen Chen, Jaime Flerlage, I.-Chan Huang, Melissa M. Hudson et al. « Impact of Competing Treatment Scenarios on Lifetime Disease Burden and Quality Adjusted Life Expectancy (QALE) Among Survivors of High-Risk Childhood Hodgkin Lymphoma (HR-HL) : A Modeling Study Based on the St. Jude Lifetime (SJLIFE) Cohort ». Blood 134, Supplement_1 (13 novembre 2019) : 267. http://dx.doi.org/10.1182/blood-2019-124907.
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Background: Children and young adults diagnosed with HR-HL have a 5-year survival rate of >95%. Yet, as compared to the general population, survivors remain at elevated risk for therapy-related early mortality and excess long-term morbidity. Second malignancies (SMNs), cardiac disease, and pulmonary complications are major contributors to excess mortality/morbidity experienced by survivors of HL. Since several treatment regimens used for younger HR-HL all offer excellent overall survival and tolerable short-term morbidity profiles, it is not clear which is best. The objective of this study was to compare the life-long impact of treatment-related toxicity and early mortality associated with 4 common treatment scenarios used to treat HR-HL. Outcomes measured included overall life expectancy (LE), 10-year post-diagnosis QALE and cause of death. Methods: A microsimulation model was developed using the lifetime horizon for a cohort of 10-year survivors of HR-HL treated with 4 common treatment scenarios utilized by pediatric and adult oncology groups. The data from 5522 adult 10-year survivors of childhood cancers in the SJLIFE cohort (56% males; mean age at last follow-up=35.3 years [y], range 18.9-67.9; ≥18y at study enrollment) was used to estimate the mortality risk and incidence of cardiac and pulmonary complications and SMNs as functions of age at primary cancer diagnosis, attained age, sex, race, and treatment exposures including cumulative doses of anthracyclines, alkylating agents, and bleomycin plus radiation dose to the heart and chest. Prospective and retrospective clinical assessments were used to obtain and grade late-effect outcomes using a modified Common Terminology Criteria for Adverse Events. Rates from population-based registries and published systematic analyses were used for background mortality, mortality risk from the complications and for extrapolation. Calibration was performed against SJLIFE data to ensure model consistency. Quality of life utility weights (ranging from 1 for perfect health to 0 for dead) associated with complications were estimated from the SJLIFE cohort. The mortality and incidence functions and utility weights were applied to the lifetime of 10,000 simulated HL survivors (same demographic distribution as in the 667 SJLIFE HL participants: 58% males; mean age at HL diagnosis=13.9y, range 3-25) starting at 10y after HL diagnosis to death to calculate the average LE and QALE associated with the 4 treatment scenarios. Results: The figure shows the results for 4 scenarios based on OEPA [vincristine, etoposide, prednisone, doxorubicin] (2 cycles) plus COPDac [cyclophosphamide, vincristine, prednisone, dacarbazine] (4 cycles) and ABVD [doxorubicin, bleomycin, vincristine, dacarbazine] (6 cycles), both with and without heart and chest radiation. The average LE for the cohort assuming general population mortality risk is 80.8y (dashed line). Average LEs associated with the 4 scenarios are represented by the asterix above each bar. The average 10-year post-diagnosis QALE and the proportion of time spent living with cardiac, pulmonary and/or SMN are depicted in the colored stacked bar-chart. The decrement in average LE due to treatment for HR-HL ranged from 12.8y for OEPA/COPDac alone to 25.8y for ABVD with radiation. OEPA/COPDac based regimens without and with radiation had higher average LE (68.1y and 64.1y, respectively) and QALE (29.9y and 27.4y, respectively) compared to the ABVD regimens (LE: 60.9y and 55.0y; QALE: 25.0y and 22.7y). The addition of radiation reduced average LE and QALE in both the OEPA/COPDac (4.0y and 2.5y) and ABVD (5.8y and 2.3y) regimens and increased the proportion of the cohort who developed pulmonary disease and SMNs for all scenarios. The cohort receiving OEPA/COPDac with radiation had similar average post-10 year QALE compared to those treated with ABVD without radiation. Increased proportional mortality due to SMN was observed among the cohort exposed to ABVD. Conclusion: Using a lifetime horizon simulation approach, we demonstrate that the OEPA/COPDac regimen results in greater average LE and QALE when compared against ABVD for HR-HL. This approach highlights a yet untapped opportunity to leverage data from survivorship cohorts by evaluating late-effect trade-offs to inform clinical trial design and aid patient decision-making when choosing between different treatment options that have similar efficacy. Disclosures No relevant conflicts of interest to declare.
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van Delft, Frederik, Mirte Muller, Rom Langerak, Hendrik Koffijberg, Valesca Retèl, Daan van den Broek et Maarten IJzerman. « Modeling Diagnostic Strategies to Manage Toxic Adverse Events following Cancer Immunotherapy ». Medical Decision Making 41, no 6 (5 avril 2021) : 693–705. http://dx.doi.org/10.1177/0272989x211002756.
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Background Although immunotherapy (IMT) provides significant survival benefits in selected patients, approximately 10% of patients experience (serious) immune-related adverse events (irAEs). The early detection of adverse events will prevent irAEs from progressing to severe stages, and routine testing for irAEs has become common practice. Because a positive test outcome might indicate a clinically manifesting irAE that requires treatment to (temporarily) discontinue, the occurrence of false-positive test outcomes is expected to negatively affect treatment outcomes. This study explores how the UPPAAL modeling environment can be used to assess the impact of test accuracy (i.e., test sensitivity and specificity), on the probability of patients entering palliative care within 11 IMT cycles. Methods A timed automata-based model was constructed using real-world data and expert consultation. Model calibration was performed using data from 248 non–small-cell lung cancer patients treated with nivolumab. A scenario analysis was performed to evaluate the effect of changes in test accuracy on the probability of patients transitioning to palliative care. Results The constructed model was used to estimate the cumulative probabilities for the patients’ transition to palliative care, which were found to match real-world clinical observations after model calibration. The scenario analysis showed that the specificity of laboratory tests for routine monitoring has a strong effect on the probability of patients transitioning to palliative care, whereas the effect of test sensitivity was limited. Conclusion We have obtained interesting insights by simulating a care pathway and disease progression using UPPAAL. The scenario analysis indicates that an increase in test specificity results in decreased discontinuation of treatment due to suspicion of irAEs, through a reduction of false-positive test outcomes.
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Touseef, Muhammad, Lihua Chen et Wenzhe Yang. « Assessment of Surface Water Availability under Climate Change Using Coupled SWAT-WEAP in Hongshui River Basin, China ». ISPRS International Journal of Geo-Information 10, no 5 (5 mai 2021) : 298. http://dx.doi.org/10.3390/ijgi10050298.
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Climate change adversely affects the hydrological cycle at the basin level. This study integrated two models, the Soil and Water Assessment Tool (SWAT) for future climate prediction, and Water Evaluation and Planning (WEAP) for the simulation of water quantity in the Hongshui River Basin (HRB), to evaluate the impacts of climate change, which plays a significant role in the lives of inhabitants downstream of the basin. Downscaled monthly rainfalls and temperatures under four Representative Concentration Pathways (RCPs) emission scenarios from five global circulation models (GCMs) were used to generate streamflow using the SWAT model. Streamflow data (1991–2001) were used to calibrate and validate, with the period of 1991–1997 used for calibration and that of 1998–2001 used for validation. Six scenarios were established to evaluate the response of the basin under socio-economic scenarios. The simulated results show that precipitation and streamflow would likely undergo a slight increase. The available water resources would be sufficient to meet the existing needs until 2050. The results indicated that no water shortages exist under socio-economic, low, and medium climate change emission scenarios, however the basin will experience a water shortage under the high climate change emission scenario (RCP-8.5). The study proposed that, to ensure the sustainability of water resources, better long-term management policies are required to be implemented in the basin and to meet future downstream water needs.
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He, Yinhong, Ping Chen, Yong Li et Shumei Zhang. « A New Online Calibration Method Based on Lord’s Bias-Correction ». Applied Psychological Measurement 41, no 6 (26 mars 2017) : 456–71. http://dx.doi.org/10.1177/0146621617697958.
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Online calibration technique has been widely employed to calibrate new items due to its advantages. Method A is the simplest online calibration method and has attracted many attentions from researchers recently. However, a key assumption of Method A is that it treats person-parameter estimates [Formula: see text] (obtained by maximum likelihood estimation [MLE]) as their true values [Formula: see text], thus the deviation of the estimated [Formula: see text] from their true values might yield inaccurate item calibration when the deviation is nonignorable. To improve the performance of Method A, a new method, MLE-LBCI-Method A, is proposed. This new method combines a modified Lord’s bias-correction method (named as maximum likelihood estimation-Lord’s bias-correction with iteration [MLE-LBCI]) with the original Method A in an effort to correct the deviation of [Formula: see text] which may adversely affect the item calibration precision. Two simulation studies were carried out to explore the performance of both MLE-LBCI and MLE-LBCI-Method A under several scenarios. Simulation results showed that MLE-LBCI could make a significant improvement over the ML ability estimates, and MLE-LBCI-Method A did outperform Method A in almost all experimental conditions.
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Bassett, William F., et David E. Rappoport. « Enhancing Stress Tests by Adding Macroprudential Elements ». Finance and Economics Discussion Series 2022, no 022 (6 mai 2022) : 1–46. http://dx.doi.org/10.17016/feds.2022.022.
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The use of stress testing for macroprudential objectives is advanced by modeling spillovers within the financial sector or between the real and financial sectors. In this chapter, we discuss several macroprudential elements that capture these spillovers and how they might be added to stress test frameworks. We show how funding spillovers can be modeled as an add-on, using a reduced-form relation between banks’ funding cost, bank capital and economic activity. Using a calibration to US data, we project very modest funding spillovers conditional on the DFAST 2018 severely adverse scenario. We describe the pros and cons of modeling different types of spillovers using this approach.
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Welderufael, W. A., Y. E. Woyessa et D. C. Edossa. « Hydrological impact of rainwater harvesting in the Modder river basin of central South Africa ». Hydrology and Earth System Sciences Discussions 8, no 3 (23 mai 2011) : 5051–81. http://dx.doi.org/10.5194/hessd-8-5051-2011.
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Abstract. Along the path of water flowing in a river basin are many water-related human interventions that modify the natural systems. Rainwater harvesting is one such intervention that involves harnessing of water in the upstream catchment. Increased water usage at upstream level is an issue of concern for downstream water availability to sustain ecosystem services. The upstream Modder River basin, located in a semi arid region in the central South Africa, is experiencing intermittent meteorological droughts causing water shortages for agriculture, livestock and domestic purpose. To address this problem a technique was developed for small scale farmers with the objective of harnessing rainwater for crop production. However, the hydrological impact of a wider adoption of this technique by farmers has not been well quantified. In this regard, the SWAT hydrological model was used to simulate the hydrological impact of such practices. The scenarios studied were: (1) Baseline scenario, based on the actual land use of 2000, which is dominated by pasture (combination of natural and some improved grass lands) (PAST); (2) Partial conversion of Land use 2000 (PAST) to conventional agriculture (Agri-CON); and (3) Partial conversion of Land use 2000 (PAST) to in-field rainwater harvesting which was aimed at improving the precipitation use efficiency (Agri-IRWH). SWAT was calibrated using observed daily mean stream flow data of a sub-catchment (419 km2) in the study area. SWAT performed well in simulating the stream flow giving Nash and Sutcliffe (1970) efficiency index of 0.57 for the monthly stream flow calibration. The simulated water balance results showed that the highest peak mean monthly direct flow was obtained on Agri-CON land use (18 mm), followed by PAST (12 mm) and Agri-IRWH land use (9 mm). These were 19 %, 13 % and 11 % of the mean annual rainfall, respectively. The Agri-IRWH scenario reduced direct flow by 38 % compared to Agri-CON. On the other hand it was found that the Agri-IRWH contributed to more groundwater flow (40 mm) compared to PAST (32 mm) and Agri-CON (19 mm) scenarios. These results are in line with the intended purpose of Agri-IRWH. Although there was a visible impact of the rainwater harvesting technique on the water yield when considered on a monthly time frame, the overall result suggests that the water yield of one of the upper Modder River Basin quaternary catchment may not be adversely affected by the Agri-IRWH land use scenario despite its surface runoff abstraction design.
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Wu, Robert, Pierrick Lamontagne-Hallé et Jeffrey M. McKenzie. « Uncertainties in Measuring Soil Moisture Content with Actively Heated Fiber-Optic Distributed Temperature Sensing ». Sensors 21, no 11 (27 mai 2021) : 3723. http://dx.doi.org/10.3390/s21113723.
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Actively heated fiber-optic distributed temperature sensing (aFO-DTS) measures soil moisture content at sub-meter intervals across kilometres of fiber-optic cable. The technology has great potential for environmental monitoring but calibration at field scales with variable soil conditions is challenging. To better understand and quantify the errors associated with aFO-DTS soil moisture measurements, we use a parametric numerical modeling approach to evaluate different error factors for uniform soil. A thermo-hydrogeologic, unsaturated numerical model is used to simulate a 0.01 m by 0.01 m two-dimensional domain, including soil and a fiber-optic cable. Results from the model are compared to soil moisture values calculated using the commonly used Tcum calibration method for aFO-DTS. The model is found to have high accuracy between measured and observed saturations for static hydrologic conditions but shows discrepancies for more realistic settings with active recharge. We evaluate the performance of aFO-DTS soil moisture calculations for various scenarios, including varying recharge duration and heterogeneous soils. The aFO-DTS accuracy decreases as the variability in soil properties and intensity of recharge events increases. Further, we show that the burial of the fiber-optic cable within soil may adversely affect calculated results. The results demonstrate the need for careful selection of calibration data for this emerging method of measuring soil moisture content.
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Casson, Andrea, Roberto Beghi, Valentina Giovenzana, Ilaria Fiorindo, Alessio Tugnolo et Riccardo Guidetti. « Visible Near Infrared Spectroscopy as a Green Technology : An Environmental Impact Comparative Study on Olive Oil Analyses ». Sustainability 11, no 9 (7 mai 2019) : 2611. http://dx.doi.org/10.3390/su11092611.
Texte intégralRésumé :
The olive oil industry is a significant productive sector in the European Union and the related production process is characterised by practices and techniques associated with several adverse effects on the environment. In the literature, many works on the environmental impact assessment of the olive oil chain have been carried out but the effects of the analytical analyses procedures were considered to be negligible. Currently, the reduction of solvents and of energy consumption in the laboratory has become a crucial aspect to be investigated. In this scenario, non-destructive optical methods based on visible/near-infrared (vis/NIR) spectroscopy represent a simple, rapid, and easy-to-use method to predict olive and olive oil quality parameters. Therefore, the aim of the work was to evaluate the environmental impact of the use of optical vis/NIR technologies for analytical assessment in comparison to chemical analyses on olive oil. The life cycle assessment method (LCA) was used. The functional unit defined for this study was the analysis and a “from cradle to grave” approach was applied. The vis/NIR technology results were distinctly better, by 36 times on average, than the chemical methods. Attention must be paid to the calibration phase of the vis/NIR instrumentation: In this case, the two methods must coexist for this initial procedure to obtain the required reference data for a reliable chemometric model. In conclusion, the vis/NIR spectroscopy gives very reliable results and can be considered a green technology, representing a choice among applications of low environmental impact analytical technologies.
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Costa, Dimitri, Rachel Kuske et Daniil Yurchenko. « Qualitative changes in bifurcation structure for soft vs hard impact models of a vibro-impact energy harvester ». Chaos : An Interdisciplinary Journal of Nonlinear Science 32, no 10 (octobre 2022) : 103120. http://dx.doi.org/10.1063/5.0101050.
Texte intégralRésumé :
Vibro-impact phenomena in engineering systems, considered an adverse effect in some settings, are an intrinsic part of the mechanism in others. In energy harvesting, a vibro-impact component is often intentionally introduced to increase the power output or the system’s bandwidth. The impacts can be treated as “hard” for instantaneous impacts or “soft” for compliant materials. Since both types of models exhibit complex dynamics, a comparison is non-trivial. We develop a soft impact model for a vibro-impact energy harvester, calibrating it with the relevant hard impact model for large stiffness, and systematically compare the different phenomena and dynamics in various compliant regimes. Numerical results are used in two different parametric analyses, considering the bifurcation diagrams in terms of device size and external forcing parameters. Varying the natural frequency of the membranes that form the impact boundaries, we observe shifts in the bifurcation structure that promote period-1 orbits for increased softness parameters, often generating higher power output, but also introducing parameter sensitivities for increased softness. Complementary analytical results reveal unstable periodic orbits and co-existing behaviors, potentially missed by computational methods, that can influence the bifurcation structure and in turn the energy output. A non-dimensional formulation highlights the significance of ratios of external and natural frequencies in delineating soft and hard impact scenarios parametrically. The soft impact model exhibits new symmetry breaking bifurcations related to key quantities that characterize the soft impact dynamics, such as the effective restitution coefficients, the impact phase, and the contact time interval, not captured by hard impact models.
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Ozener, Orkun, et Muammer Ozkan. « Assesment of real driving emissions of a bus operating on a dedicated route ». Thermal Science 24, no 1 Part A (2020) : 63–73. http://dx.doi.org/10.2298/tsci180921349o.
Texte intégralRésumé :
The reducing of real driving emissions from public transportation which is using intracity lines has become more important in recent years. This is because the petroleum derived fuel combustion products contributes the global warming as well as adversely the air quality. The fuel consumption perspective is another major economical concern for operating companies that should be optimized. In this context a part of Istanbul Metrobus public transportation system of which is using fully a dedicated line is assessed via on board emission and fuel metering devices for two loading conditions. The relevant vehicle and engine operating data is logged during the tests. The logged data is post processed for developing the average emission factors. The results are also analyzed from acceleration and altitude change perspective and alternative scenarios are discussed for cleaner and economic operation. Lastly the in-service conformity parameters are identified and the results are compared with homologation values. It was found that for the same velocity, acceleration affect was found significant and the critical acceleration level is determined as 0.4 m/s?. For NOx, and CO emissions velocities smaller than 20 km/h and 40 km/h was found dominant at positive acceleration zones. Also for fuel consumption and CO2 emission levels the velocities higher than 30 km/h was found critical for all positive acceleration levels. It was shown that the real driving and emission data can be used efficiently for developing more environmentally friendly engine calibrations and decreasing fuel consumption and emissions.
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de Waal, J. A., A. G. Muntendam-Bos et J. P. A. Roest. « Production induced subsidence and seismicity in the Groningen gas field – can it be managed ? » Proceedings of the International Association of Hydrological Sciences 372 (12 novembre 2015) : 129–39. http://dx.doi.org/10.5194/piahs-372-129-2015.
Texte intégralRésumé :
Abstract. Reliable prediction of the induced subsidence resulting from gas production is important for a near sea level country like the Netherlands. Without the protection of dunes, dikes and pumping, large parts of the country would be flooded. The predicted sea-level rise from global warming increases the challenge to design proper mitigation measures. Water management problems from gas production induced subsidence can be prevented if measures to counter its adverse effects are taken timely. This requires reliable subsidence predictions, which is a major challenge. Since the 1960's a number of large, multi-decade gas production projects were started in the Netherlands. Extensive, well-documented subsidence prediction and monitoring technologies were applied. Nevertheless predicted subsidence at the end of the Groningen field production period (for the centre of the bowl) went from 100 cm in 1971 to 77 cm in 1973 and then to 30 cm in 1977. In 1984 the prediction went up again to 65 cm, down to 36 cm in 1990 and then via 38 cm (1995) and 42 cm (2005) to 47 cm in 2010 and 49 cm in 2013. Such changes can have large implications for the planning of water management measures. Until 1991, when the first event was registered, production induced seismicity was not observed nor expected for the Groningen field. Thereafter the number of observed events rose from 5 to 10 per year during the 1990's to well over a hundred in 2013. The anticipated maximum likely magnitude rose from an initial value of less than 3.0 to a value of 3.3 in 1993 and then to 3.9 in 2006. The strongest tremor to date occurred near the village of Huizinge in August 2012. It had a magnitude of 3.6, caused significant damage and triggered the regulator into an independent investigation. Late 2012 it became clear that significantly larger magnitudes cannot be excluded and that values up to magnitude 5.0 cannot be ruled out. As a consequence the regulator advised early 2013 to lower Groningen gas production by as much and as fast as realistically possible. Before taking such a decision, the Minister of Economic Affairs requested further studies. The results became available early 2014 and led to the government decision to lower gas production in the earthquake prone central area of the field by 80 % for the next three~years. In addition further investigations and a program to strengthen houses and infrastructure were started. Important lessons have been learned from the studies carried out to date. It is now realised that uncertainties in predicted subsidence and seismicity are much larger than previously recognised. Compaction, subsidence and seismicity are strongly interlinked and relate in a non-linear way to production and pressure drop. The latest studies by the operator suggest that seismic hazard in Groningen is largely determined by tremors with magnitudes between 4.5 and 5.0 even at an annual probability of occurrence of less than 1 %. And that subsidence in 2080 in the centre of the bowl could be anywhere between 50 and 70 cm. Initial evaluations by the regulator indicate similar numbers and suggest that the present seismic risk is comparable to Dutch flooding risks. Different models and parameters can be used to describe the subsidence and seismicity observed so far. The choice of compaction and seismicity models and their parameters has a large impact on the calculated future subsidence (rates), seismic activity and on the predicted response to changes in gas production. In addition there are considerable uncertainties in the ground motions resulting from an earthquake of a given magnitude and in the expected response of buildings and infrastructure. As a result uncertainties in subsidence and seismicity become very large for periods more than three to five years into the future. To counter this a control loop based on interactive modelling, measurements and repeated calibration will be used. Over the coming years, the effect of the production reduction in the centre of the field on subsidence and seismicity will be studied in detail in an effort to improve understanding and thereby reduce prediction uncertainties. First indications are that the reduction has led to a drop in subsidence rate and seismicity within a period of a few months. This suggests that the system can be controlled and regulated. If this is the case, the integrated loop of predicting, monitoring and updating in combination with mitigation measures can be applied to keep subsidence (rate) and induced seismicity within limits. To be able to do so, the operator has extended the field-monitoring network. It now includes PS-InSAR and GPS stations for semi-permanent subsidence monitoring in addition to a traditional network of levelling benchmarks. For the seismic monitoring 60 shallow (200 m) borehole seismometers, 60 + accelerometers and two permanent downhole seismic arrays at reservoir level will be added. Scenario's spanning the range of parameter and model uncertainties will be generated to calculate possible subsidence and seismicity outcomes. The probability of each scenario will be updated over time through confrontation with the measurements as they become available. At regular intervals the subsidence prediction and the seismic risk will be re-evaluated. Further mitigation measures, possibly including further production measures will need to be taken if probabilities indicate unacceptable risks.
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Dash, Sonam S., Dipaka R. Sena, Uday Mandal, Anil Kumar, Gopal Kumar, Prasant K. Mishra et Monika Rawat. « A hydrological modelling-based approach for vulnerable area identification under changing climate scenarios ». Journal of Water and Climate Change, 21 avril 2020. http://dx.doi.org/10.2166/wcc.2020.202.
Texte intégralRésumé :
Abstract The hydrologic behaviour of the Brahmani River basin (BRB) (39,633.90 km2), India was assessed for the base period (1970–1999) and future climate scenarios (2050) using the Soil and Water Assessment Tool (SWAT). Monthly streamflow data of 2000–2009 and 2010–2012 was used for calibration and validation, respectively, and performed satisfactorily with Nash-Sutcliffe Efficiency (ENS) of 0.52–0.55. The projected future climatic outcomes of the HadGEM2-ES model indicated that minimum temperature, maximum temperature, and precipitation may increase by 1.11–3.72 °C, 0.27–2.89 °C, and 16–263 mm, respectively, by 2050. The mean annual streamflow over the basin may increase by 20.86, 11.29, 4.45, and 37.94% under RCP 2.6, 4.5, 6.0, and 8.5, respectively, whereas the sediment yield is likely to increase by 23.34, 10.53, 2.45, and 27.62% under RCP 2.6, 4.5, 6.0, and 8.5, respectively, signifying RCP 8.5 to be the most adverse scenario for the BRB. Moreover, a ten-fold increase in environmental flow (defined as Q90) by the mid-century period is expected under the RCP 8.5 scenario. The vulnerable area assessment revealed that the increase in moderate and high erosion-prone regions will be more prevalent in the mid-century. The methodology developed herein could be successfully implemented for identification and prioritization of critical zones in worldwide river basins.
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Jiang, Rong, Wentian He, Liang He, J. Y. Yang, B. Qian, Wei Zhou et Ping He. « Modelling adaptation strategies to reduce adverse impacts of climate change on maize cropping system in Northeast China ». Scientific Reports 11, no 1 (12 janvier 2021). http://dx.doi.org/10.1038/s41598-020-79988-3.
Texte intégralRésumé :
AbstractMaize (Zea mays L.) production in Northeast China is vulnerable to climate change. Thus, exploring future adaptation measures for maize is crucial to developing sustainable agriculture to ensure food security. The current study was undertaken to evaluate the impacts of climate change on maize yield and partial factor productivity of nitrogen (PFPN) and explore potential adaptation strategies in Northeast China. The Decision Support System for Agrotechnology Transfer (DSSAT) model was calibrated and validated using the measurements from nine maize experiments. DSSAT performed well in simulating maize yield, biomass and N uptake for both calibration and validation periods (normalized root mean square error (nRMSE) < 10%, −5% < normalized average relative error (nARE) < 5% and index of agreement (d) > 0.8). Compared to the baseline (1980–2010), the average maize yields and PFPN would decrease by 7.6–32.1% and 3.6–14.0 kg N kg−1 respectively under future climate scenarios (2041–2070 and 2071–2100) without adaptation. Optimizing N application rate and timing, establishing rotation system with legumes, adjusting planting dates and breeding long-season cultivars could be effective adaptation strategies to climate change. This study demonstrated that optimizing agronomic crop management practices would assist to make policy development on mitigating the negative impacts of future climate change on maize production.
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Murasingh, S., J. Kuttippurath, S. Sandeep Dash, S. Raj, R. Remesan, Madan K. Jha et P. Kumar. « Long-term trends and projections of hydrological fluxes under RCP climate change scenarios for a mountainous river catchment of northeast India ». Journal of Water and Climate Change, 8 mars 2022. http://dx.doi.org/10.2166/wcc.2022.424.
Texte intégralRésumé :
Abstract The estimate of changes in hydrological fluxes from a climate change perspective is inevitable for assessing the sustainability of watersheds and conserving water resources. Here, we quantify and assess the changes in different hydrological flux components for the Manu-Deo River Basin (MDRB) of northeast India using Soil and Water Assessment Tool (SWAT) simulations and multi-temporal data at various resolutions. Sequential Uncertainty Fitting (SUFI-2) optimization is used to calibrate and validate the simulations for the periods 1984–2006 and 2007–2016 and for the four future representative concentration pathway (RCP) scenarios. The model performed reasonably well for the calibration and validation of daily data, in accordance with the Nash–Sutcliffe efficiency and coefficient of determination (0.54/0.55 and 0.52/0.72, respectively). The analysis for the period 1985–2013 reveals a decreasing trend in streamflow, which indicates increasing trends of drought there. Furthermore, it shows an increasing trend in evapotranspiration (ET) and decreasing trend for baseflow (BF), suggesting an adverse impact on agricultural production during lean periods. In addition, the RCP 2.6 and 6.0 scenarios for the monsoon season in future time scales are expected to cause a reduction in different flow components, although RCP 8.5 shows increased water availability there. The sub-basin-scale quantification and multi-temporal analysis of water availability under the present and future climate scenarios, as presented here, can assist water managers in formulating a suitable operational policy to implement a better decision-making framework for river and waterbody management. This is particularly important for mountainous regions, where input data are sparse and modelling of hydrological fluxes is challenging.
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Jobst, Andreas A., et Hiroko Oura. « Sovereign Risk in Macroprudential Solvency Stress Testing ». IMF Working Papers 19, no 266 (6 décembre 2019). http://dx.doi.org/10.5089/9781513519968.001.
Texte intégralRésumé :
This paper explains the treatment of sovereign risk in macroprudential solvency stress testing, based on the experiences in the Financial Sector Assessment Program (FSAP). We discuss four essential steps in assessing the system-wide impact of sovereign risk: scope, loss estimation, shock calibration, and capital impact calculation. Most importantly, a market-consistent valuation approach lies at the heart of assessing the resilience of the financial sector in a tail risk scenario with sovereign distress. We present a flexible, closed-form approach to calibrating haircuts based on changes in expected sovereign defaults affecting bank solvency during adverse macroeconomic conditions. This paper demonstrates the effectiveness of using extreme value theory (EVT) in this context, with empirical examples from past FSAPs.
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Mohammed, Adem, et Abebe Misganaw. « Modeling future climate change impacts on sorghum (Sorghum bicolor) production with best management options in Amhara Region, Ethiopia ». CABI Agriculture and Bioscience 3, no 1 (25 avril 2022). http://dx.doi.org/10.1186/s43170-022-00092-9.
Texte intégralRésumé :
AbstractSorghum is one of the most important cereal crops well adapted in arid and semi-arid areas of Ethiopia but yield is low as compared to its potential. The crop has been adversely affected by climate change and climate variability accompanied by low soil fertility, insects and weeds. Thus, assessment of impact of projected climate change is important for developing suitable management strategies. The present study was conducted with the objectives (1) to calibrate and evaluate the CERES-sorghum model in DSSAT (2) to assess impact of projected climate change on sorghum production in 2030s (2020–2049) and 2050s (2040–2069) under RCP4.5 and RCP8.5 scenarios and (3) to identify best crop management strategies that can sustain sorghum production. The CERES-sorghum model was calibrated and evaluated using field experimental data of anthesis, physiological maturity, grain yield and aboveground biomass yield. In the simulation, the initial weather and CO2 were modified by future climates under the two climatic change scenarios (RCP4.5 and RCP8.5). Historical daily weather data (1981–2010) of rainfall, maximum temperature, minimum temperature, and solar radiation were obtained from the nearest weather stations at Sirinka and Kombolcha while future climate date for 2030s and 2050s were downloaded from the ensemble of 17 CMIP5 GCM outputs run under RCP4.5 and RCP8.5 downscaled to the study sites using MarkSim. Different sowing dates, nitrogen rates, and supplemental irrigation were evaluated for their effectiveness to increase sorghum yield under the present and future climate conditions of the study area. The result of model calibration showed that the RMSE for anthesis, physiological maturity, grain yield, and above-ground biomass yield were 2 days, 2 days, 478 kg ha−1, and 912 kg ha−1, respectively with normalized nRMSE values of 2.74%, 1.6%, 13.42%, and 5.91%, respectively. During the model evaluation the R2 values were 78% for anthesis, 99% for physiological maturity, 98% for aboveground biomass yield, and 94% for grain yield. The d-statistics values were 0.87, 0.91, 0.67, and 0.98 while the nRMSE values were 2.6%, 2.7%, 23.4%, and 4.1% for the respective parameters. The result of statistical analysis for both model calibration and evaluation revealed that there existed strong fit between the simulated and observed values that indicated the model can be used for different application to improve sorghum productivity in the region. The result of impact analysis showed that sorghum grain yield may decrease by 2030s and 2050s under both RCPs scenarios. However, the result of management scenarios showed that sorghum yield may be substantially increased through use of optimum nitrogen fertilizer, application of supplemental irrigation and by using early sowing dates individually or in combination. In conclusion, projected climate change could adversely affect sorghum production in the semi-arid areas of Ethiopia in the present and future climate conditions but impact could be reduced by using suitable crop management strategies.
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Mohammed, Adem, et Abebe Misganaw. « Modeling future climate change impacts on sorghum (Sorghum bicolor) production with best management options in Amhara Region, Ethiopia ». CABI Agriculture and Bioscience 3, no 1 (25 avril 2022). http://dx.doi.org/10.1186/s43170-022-00092-9.
Texte intégralRésumé :
AbstractSorghum is one of the most important cereal crops well adapted in arid and semi-arid areas of Ethiopia but yield is low as compared to its potential. The crop has been adversely affected by climate change and climate variability accompanied by low soil fertility, insects and weeds. Thus, assessment of impact of projected climate change is important for developing suitable management strategies. The present study was conducted with the objectives (1) to calibrate and evaluate the CERES-sorghum model in DSSAT (2) to assess impact of projected climate change on sorghum production in 2030s (2020–2049) and 2050s (2040–2069) under RCP4.5 and RCP8.5 scenarios and (3) to identify best crop management strategies that can sustain sorghum production. The CERES-sorghum model was calibrated and evaluated using field experimental data of anthesis, physiological maturity, grain yield and aboveground biomass yield. In the simulation, the initial weather and CO2 were modified by future climates under the two climatic change scenarios (RCP4.5 and RCP8.5). Historical daily weather data (1981–2010) of rainfall, maximum temperature, minimum temperature, and solar radiation were obtained from the nearest weather stations at Sirinka and Kombolcha while future climate date for 2030s and 2050s were downloaded from the ensemble of 17 CMIP5 GCM outputs run under RCP4.5 and RCP8.5 downscaled to the study sites using MarkSim. Different sowing dates, nitrogen rates, and supplemental irrigation were evaluated for their effectiveness to increase sorghum yield under the present and future climate conditions of the study area. The result of model calibration showed that the RMSE for anthesis, physiological maturity, grain yield, and above-ground biomass yield were 2 days, 2 days, 478 kg ha−1, and 912 kg ha−1, respectively with normalized nRMSE values of 2.74%, 1.6%, 13.42%, and 5.91%, respectively. During the model evaluation the R2 values were 78% for anthesis, 99% for physiological maturity, 98% for aboveground biomass yield, and 94% for grain yield. The d-statistics values were 0.87, 0.91, 0.67, and 0.98 while the nRMSE values were 2.6%, 2.7%, 23.4%, and 4.1% for the respective parameters. The result of statistical analysis for both model calibration and evaluation revealed that there existed strong fit between the simulated and observed values that indicated the model can be used for different application to improve sorghum productivity in the region. The result of impact analysis showed that sorghum grain yield may decrease by 2030s and 2050s under both RCPs scenarios. However, the result of management scenarios showed that sorghum yield may be substantially increased through use of optimum nitrogen fertilizer, application of supplemental irrigation and by using early sowing dates individually or in combination. In conclusion, projected climate change could adversely affect sorghum production in the semi-arid areas of Ethiopia in the present and future climate conditions but impact could be reduced by using suitable crop management strategies.
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Alejo, Lanie A. « Assessing the impacts of climate change on aerobic rice production using the DSSAT-CERES-Rice model ». Journal of Water and Climate Change, 5 juin 2020. http://dx.doi.org/10.2166/wcc.2020.286.
Texte intégralRésumé :
Abstract This study assessed the impacts of climate change on aerobic rice production using the DSSAT-CERES-Rice model. Actual data observed from four cropping seasons in two sites were used for calibration and validation. Four Representative Concentration Pathway scenarios were used to simulate climate change. The optimum planting windows were simulated across these scenarios. Results showed that DSSAT-CERES-Rice could adequately simulate aerobic rice production. Changes in seasonal rainfall and increases in temperature especially during dry seasons adversely affected aerobic rice production. Reduction of rainfall during the wet seasons favored aerobic rice production. Yield losses are twice larger than gains. Changes in climate could cause yield improvements to decline from 83% to 53% and yield reductions to increase from 150% to 177% towards the end of the 21st century. Selecting the best planting windows could optimize production to avoid huge economic losses. Optimum planting windows were simulated during normal, dry, and wet climate conditions. The derived set of genetic coefficients could be used to assess various aerobic rice farm crop and nutrient management strategies as well as other climate and soil conditions. The long-term projections on aerobic rice production could guide policy and decision-makers on designing long-term climate change adaptation and mitigation plans and programs.
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Lane, Paul James, Robyn Clay-Williams, Andrew Johnson, Vidula Garde et Leah Barrett-Beck. « Creating a healthcare variant CYNEFIN framework to improve leadership and urgent decision-making in times of crisis ». Leadership in Health Services ahead-of-print, ahead-of-print (16 août 2021). http://dx.doi.org/10.1108/lhs-03-2021-0013.
Texte intégralRésumé :
Purpose The complex and occasionally chaotic nature of health care has been previously described in the literature, as has the broadening recognition that different management approaches are required for different types of problems rather than a “one size fits all” approach. The CYNEFIN framework from Snowden outlines a consistent cognitive approach that offers the leader and leadership team an ability to urgently apply the correct actions to a given situation. This paper proposes a variant CYNEFIN approach for healthcare. Design/methodology/approach Consistent and accurate decision-making within health care is the hallmark of an effective and pragmatic leader and leadership team. An awareness of how one’s cognitive biases and heuristics may adversely impact on this cognitive process is paramount, as is an understanding of the calibration between fast and slow thinking. Findings The authors propose a variant CYNEFIN approach for health care of “act-probe-sense-respond” to resolve complex and time-critical emergency scenarios, using the differing contexts of a cardiac arrest and an evolving crisis management problem as examples. The variant serves as a pragmatic sense-making framework for the health-care leader and leadership team that can be adopted for many time-critical crisis situations. Originality/value The variant serves as a pragmatic sense-making framework for the health-care leader that can be adopted for many crisis situations.
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Kizildag, Murat, Jeffrey Thomas Weinland et Ilhan Demirer. « Financial sensitivity analysis of small lodging establishments during COVID-19 ». Journal of Hospitality and Tourism Insights, 24 novembre 2022. http://dx.doi.org/10.1108/jhti-05-2022-0176.
Texte intégralRésumé :
PurposeThe main stance of this paper is to draw an authentic and rigorous outlook in terms of the financial and operational performance of small lodging establishments (SLEs) and put forth achievable and practical economic solutions that demonstrate the relative effectiveness of the adopted measures. This paper also suggests practical solutions to help minimize SLEs' financial vulnerability to long-term crisis and to boost their resilience with relative measures by applying recovery revival strategies for this particular segment of the lodging industry.Design/methodology/approachThe authors have picked a locally owned resort hotel in Central Florida area and structured a real-life, case study-based inductive approach that is purposeful and offers rich economic outlook and analysis for the entire lodging industry, especially for the resort-hotel type of accommodation facilities. The main reason for why they only focus on one company is that they can fully understand the financial effects of COVID-19 on resort type of hotels and layout countering strategies. To achieve paper objectives, they have implemented cost–benefit (C–B), break-even (B-E) analyses along with a sensitivity testing approach.FindingsThe most striking result was that during the state-mandated shutdown period in 2020, overhead and overall operational costs associated with room sales and revenues were very high during this period that shrank the contribution margin ratio for rooms CMRw (room) and eventually yielded high sales volumes to be achieved at the B-E points vs lower sales volumes with almost the same average daily rate (ADR) levels needed for the B-E levels.Research limitations/implicationsFuture studies should specifically delve further into a portfolio of SLEs in the region or state or nation wise because the units comprising the SLEs might be too small to muster the changes required to bounce forward for the entire lodging industry in the world.Practical implicationsThe resort's revenue re-optimization focus should center on financial re-benchmarking and business re-viability stress under different levels of shock scenarios. According to the different scenarios and calibrations for the ADRs, room nights, net present values (NPVs) of cash flows and profit margins derived from our main analyses, minimizing expenses and preserving cash would be the best key strategy for financial recovery during an ongoing COVID-19 pandemic.Originality/valueIt is obvious that the lodging, hospitality and tourism industry are the hardest-hit industries by the harsh and adverse effects of COVID-19. The effects of pandemic are differently shaped on operations in different industries and subsectors. Therefore, the operational and financial evaluation for the SLEs as the core and a catalyst in the entire lodging industry can shed a light on the strategic financial recovery procedures with broadly applicable real-life and endogenous capabilities and reasoning.