@article{koohestani_stepanyants_allahdadi_2023, title={Analysis of Internal Solitary Waves in the Gulf of Oman and Sources Responsible for Their Generation}, volume={15}, ISSN={["2073-4441"]}, DOI={10.3390/w15040746}, abstractNote={A combination of multiple data sources has been used to study the characteristics of internal solitary waves (ISWs) in the Gulf of Oman (GoO). Water column stratification in the Gulf has been examined using field observations and World Ocean Atlas 2018 datasets. The spatiotemporal distribution of ISWs has been obtained from satellite images obtained by means of Synthetic Aperture Radar (SAR) and optical sensors taken from 2018 to 2020. The mechanisms of ISW generation in the GoO have been studied using the data revealed from different available sources. The results show that there are annually two major typical stratifications in the GoO throughout the year, strong stratification in May through September and weak stratification during other months. Dispersion relations corresponding to these types of stratification have been obtained with acceptable accuracy for both deep and shallow regions. The spatiotemporal distribution of ISWs demonstrates that the western and southern regions of the GoO are the hotspots for generation of ISWs in this basin. Several mechanisms of ISW generation in the GoO are discussed including tide, eddies, lee waves, and atmospheric perturbation; the latter one is, apparently, responsible for the appearance of large-amplitude ISWs.}, number={4}, journal={WATER}, author={Koohestani, Kamran and Stepanyants, Yury and Allahdadi, Mohammad Nabi}, year={2023}, month={Feb} }
 @article{allahdadi_he_neary_2023, title={Impact of the Gulf Stream on ocean waves}, volume={208}, ISSN={["1879-0100"]}, DOI={10.1016/j.dsr2.2022.105239}, abstractNote={Surface wave propagation and the modulations of wave parametric and spectral properties over the Gulf Stream (GS) are studied using a high spatial resolution (1 km) wave model that considers an idealized GS. While simulation results are generally consistent with a previous modelling study, we found that for following-current (FC) cases, reflection from the GS substantially increases wave height on the offshore side of the GS center by up to 25%, and decreases wave height on the landward side of the GS by as much as 80%. In the counter-current (CC) cases, the wave height profile is more symmetrical relative to the GS centerline, and the maximum 33% increase of wave height is predominantly driven by straining. The GS also causes an increase (decrease) in wavelength and directional spreading in the FC (CC) case. Additional model sensitivity experiments that further consider realistic shelf-ocean topography show that current modulation and bottom dissipation work in concert as low- and high-pass filters on the wave frequency spectra. Wave parameters and spectral modulations imposed by the GS have significant impacts on ocean-atmosphere momentum flux and wave energy resource.}, journal={DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY}, author={Allahdadi, Mohammad Nabi and He, Ruoying and Neary, Vincent S.}, year={2023}, month={Apr} }
 @article{chaichitehrani_li_xu_hestir_allahdadi_2023, title={Sediment dynamics over a dredge pit during summer fair weather conditions: A numerical study for Sandy Point, west flank of the Mississippi River}, volume={269}, ISSN={["1873-5258"]}, DOI={10.1016/j.oceaneng.2022.113473}, abstractNote={A coupled Flow-Wave-Sediment model was used to study hydrodynamics, sedimentation, and bottom boundary layer (BBL) dynamics over the Sandy Point Dredge Pit (SPDP; a potential sand mining site in the Louisiana shelf, northern Gulf of Mexico) during fair weather summer conditions (July and August 2015). The Delft3D modeling system on a curvilinear computational grid with spatial resolution between 10 m and 2.8 km was used. The flow, wave, and sediment transport models were evaluated using water level, current speed, wave parameters, and sediment concentration. During this period, the wind over the Louisiana shelf is characterized as low energy with the prevailing direction from southeast to the southwest, which corresponds to small wave heights (Hs < 1.2 m) and small wave periods (Tm < 4 s). The relatively shorter waves resuspended sediments only in very shallow areas along the Mississippi Birdfoot Delta. Simulations with and without the SPDP showed that the presence of the pit could decrease the speed of surface currents by as much as 19%, while its effect on wave characteristics was minor. The northward current produced by the prevailing winds transported the discharged sediments from the Mississippi River contributed 60% of the sedimentation over the SPDP. Sediment re-suspension inside the BBL of the SPDP occurred during the days that more energetic waves propagated over the shelf. As a result, sediments from the Mississippi River significantly increased the sediment concentration near the bottom of and throughout the water column above the SPDP.}, journal={OCEAN ENGINEERING}, author={Chaichitehrani, Nazanin and Li, Chunyan and Xu, Kehui and Hestir, Erin L. and Allahdadi, Mohammad Nabi}, year={2023}, month={Feb} }
 @article{rahimian_beyramzadeh_siadatmousavi_allahdadi_2023, title={Simulating Meteorological and Water Wave Characteristics of Cyclone Shaheen}, volume={14}, ISSN={["2073-4433"]}, DOI={10.3390/atmos14030533}, abstractNote={The Bay of Bengal and Arabian Sea are annually exposed to severe tropical cyclones, which impose massive infrastructure damages and cause the loss of life in coastal regions. Cyclone Shaheen originally generated in the Bay of Bengal in 2021 and translated a rare east-to-west path toward the Arabian Sea. Although the cyclone’s wind field can be obtained from reanalysis datasets such as ERA5 (fifth generation European Centre for Medium-Range Weather Forecasts), the wind speed cannot be reproduced with realistic details in the regions close to the center of cyclone due to spatial resolution. In this study, to address this problem, the high-resolution advanced Weather Research and Forecasting (WRF) model is used for simulation of Shaheen’s wind field. As a critical part of the study, the sensitivity of the results to the planetary boundary layer (PBL) parameterization in terms of the track, intensity, strength and structure of the cyclone Shaheen is investigated. Five experiments are considered with five PBL schemes: Yonsei University (YSU); Mellor–Yamada–Janjić (MYJ); Mellor–Yamada–Nakanishi–Niino level 2.5 (MYNN); Asymmetric Convective Model version 2 (ACM2); Quasi-Normal Scale Elimination (QNSE). The track, intensity, and strength of the experiments are compared with the wind fields obtained from the Joint Typhoon Warning Centre (JTWC) dataset. The results imply the high dependency of the track, intensity, and strength of the cyclone to the PBL parameterization. Simulated tracks with non-local PBL schemes (YSU and ACM2) outperformed those of the local PBL schemes (MYJ, MYNN, and QNSE), especially during the rapid intensification phase of Shaheen before landfall. The YSU produced highly intensified storm, while the ACM2 results are in better agreement with the JTWC data. The most accurate track was obtained from the ERA5 data; however, this dataset overestimated the spatial size and underestimated the wind speed. The WRF model using either YSU or ACM2 overestimated the wind speed compared to that of the altimeter data. The YSU and ACM2 schemes were able to reproduce the observed increase in wind speed and pressure drop at in situ stations. The wind data from EAR5 and cyclone parametric model were applied to the SWAN model to simulate the wave regime in the Arabian Sea during the time that Shaheen was translating across the region. Janssen formulation for wind input and whitecapping dissipation source terms in combination with both ERA5 and hybrid wind were used and the minimum combined error in the prediction of significant wave height (Hs) and zero up-crossing wave period (Tz) was examined. The maximum significant wave height for hybrid wind is higher than that of ERA5, while the cyclone development was successfully inferred from the wave field of the hybrid data.}, number={3}, journal={ATMOSPHERE}, author={Rahimian, Mohsen and Beyramzadeh, Mostafa and Siadatmousavi, Seyed Mostafa and Allahdadi, Mohammad Nabi}, year={2023}, month={Mar} }
 @article{allahdadi_li_chaichitehrani_2023, title={Stratification Breakdown by Fall Cold Front Winds over the Louisiana Shelf in the Northern Gulf of Mexico: A Numerical Experiment}, volume={11}, ISSN={["2077-1312"]}, DOI={10.3390/jmse11030673}, abstractNote={Cold fronts are meteorological phenomena that impact the northern Gulf of Mexico, mostly between the fall and spring seasons. On average, they pass the region every 3–7 days, with a duration ranging between 24 and 74 h. In the present study, a high-resolution FVCOM model with an unstructured mesh was used to simulate the effect of the fall cold front winds on water column mixing over the Louisiana shelf, which is often stratified in the summer, leading to hypoxia. Numerical experiments were conducted for October 2009, a period with five consecutive cold front events. Winds from an offshore station forced the model, while climatological temperature/salinity profiles prepared by NOAA for September were used for model initialization. The model performance was evaluated by comparing it with the surface current measurements at two offshore stations, and the results showed a good agreement between the model results and observations. Shelf mixing and stratification were investigated through examining the simulated sea surface temperature as well as the longitudinal and cross-shelf vertical sections. Simulation results showed a significant effect on shelf mixing, with the mixed layer depth increasing from the initial values of 5 m to 25 m at the end of simulation at different parts of the shelf, with maximum mixed layer depths corresponding to the peak of cold fronts. The buoyancy frequency, Richardson number, and the average potential energy demand (APED) for mixing the water column were used to quantify the stratification at two selected locations over the shelf. Results showed that all these parameters almost continuously decreased due to mixing induced by cold front wind events during this time. At the station off the Terrebonne Bay with a water depth of 20 m, the water column became fully mixed after three of the cold front events, with Richardson numbers smaller than 0.25 and approaching zero. This continued mixing trend was also proven by obtaining a decreasing trend of APED from 100 to 5 kg/m.s2 with several close to zero energy demand values.}, number={3}, journal={JOURNAL OF MARINE SCIENCE AND ENGINEERING}, author={Allahdadi, Mohammad Nabi and Li, Chunyan and Chaichitehrani, Nazanin}, year={2023}, month={Mar} }
 @article{allahdadi_li_chaichitehrani_2022, title={Numerical Experiments of Temperature Mixing and Post-Storm Re-Stratification over the Louisiana Shelf during Hurricane Katrina (2005)}, volume={10}, ISSN={["2077-1312"]}, DOI={10.3390/jmse10081082}, abstractNote={Studying mixing and re-stratification during and after hurricanes have important implications for the simulation of circulation and bio-geochemical processes in oceanic and shelf waters. Numerical experiments using FVCOM on an unstructured computational mesh were implemented to study the direct effect of hurricane winds on the mixing and temperature redistribution of the stratified Louisiana shelf during Hurricane Katrina (2005), as well as the post-storm re-stratification timescale. The model was forced by Katrina’s wind stress obtained from a combination of H-Wind database and NCEP model. The climatological profiles of temperature and salinity for August (the month in which Katrina occurred) from the world ocean atlas (WOA, 2013) were used as the pre-storm conditions over the shelf. Model results for sea surface temperature (SST) and mixed layer depth (MLD) were validated versus SST data from an optimally interpolated satellite product, and the MLD was calculated from the heat budget equation of the mixed layer. Model results were used to examine the temporal and spatial responses of SST and MLD over the shelf to Katrina. Results showed that intense mixing occurred within 1–1.1 RMW (RMW is the radius of maximum wind for Katrina), with turbulent mixing as the dominant mixing force for regions far from the eye, although upwelling was an important contributor to modulating SST and MLD. During the peak of Katrina and for the shelf regions severely affected by the hurricane wind, three distinct temperature zones were formed across the water column: an upper mixed layer, a transition zone, and a lower upwelling zone. Shelf re-stratification started from 3 h to more than two weeks after the landfall, depending on the distance from the track. The mixing during Hurricane Katrina affected the seasonal summertime hypoxic zone over the Louisiana shelf and likely contributed to the water column re-oxygenation.}, number={8}, journal={JOURNAL OF MARINE SCIENCE AND ENGINEERING}, author={Allahdadi, Mohammad Nabi and Li, Chunyan and Chaichitehrani, Nazanin}, year={2022}, month={Aug} }
 @article{chaichitehrani_allahdadi_li_2022, title={Simulation of Low Energy Waves during Fair-Weather Summer Conditions in the Northern Gulf of Mexico: Effect of Whitecapping Dissipation and the Forcing Accuracy}, volume={13}, ISSN={["2073-4433"]}, DOI={10.3390/atmos13122047}, abstractNote={Simulating WAves Nearshore (SWAN) on a structured grid over the Louisiana shelf in the northern Gulf of Mexico is used to evaluate the performance of three different classes of formulations for quantifying wind input and whitecapping dissipation. The formulations include Komen based on the mean spectral parameters, Westhuysen based on the saturation concept of the wave groups, and the most recent observation-based physics package ST6. The evaluation was implemented for two summer months (July and August 2015) to assess these formulations for a low wave energy period. The modeling area consists of the Louisiana inner shelf with the offshore open boundary located beyond the continental shelf. The model was forced using the spatially variable Climate Forecast System Reanalysis (CFSR) wind field and wave parameters obtained from the NOAA’s WAVEWATCH-III (WWIII) model along the open boundaries. Simulated wave parameters and spectra regarding each formulation were evaluated and compared with measured wave data at NDBC stations; comparisons showed that the most appropriate formulation for the simulation of low energy waves for the study area to be ST6. The e performance of each whitecapping formulation was described by examining 1D/2D spectra and the source term balance at different met-ocean conditions during the simulation period. It was also shown that the inaccuracies in the input wind field and boundary conditions can substantially contribute to the model inaccuracy.}, number={12}, journal={ATMOSPHERE}, author={Chaichitehrani, Nazanin and Allahdadi, Mohammad Nabi and Li, Chunyan}, year={2022}, month={Dec} }
 @article{isaie moghaddam_allahdadi_ashrafi_chaichitehrani_2021, title={Coastal system evolution along the southeastern Caspian Sea coast using satellite image analysis: response to the sea level fall during 1994-2015}, volume={14}, ISBN={1866-7538}, DOI={10.1007/s12517-021-07106-2}, number={9}, journal={ARABIAN JOURNAL OF GEOSCIENCES}, author={Isaie Moghaddam, Ehsan and Allahdadi, Mohammad Nabi and Ashrafi, Ali and Chaichitehrani, Nazanin}, year={2021}, month={May} }
 @article{allahdadi_he_ahn_chartrand_neary_2021, title={Development and calibration of a high-resolution model for the Gulf of Mexico, Puerto Rico, and the US Virgin Islands: Implication for wave energy resource characterization}, volume={235}, ISSN={["1873-5258"]}, url={https://doi.org/10.1016/j.oceaneng.2021.109304}, DOI={10.1016/j.oceaneng.2021.109304}, abstractNote={A high-resolution, unstructured Simulating WAves Nearshore (SWAN) model with a resolution of 200 m within 20 km of the coast was developed to provide a reliable setting for a long-term wave energy characterization of the Gulf of Mexico, Puerto Rico, and the U.S. Virgin Islands. A thorough model parameter sensitivity analysis, as well as a calibration process for selecting the whitecapping dissipation formulation, were conducted. Sensitivity analyses for the simulation timestep and number of iterations highlighted the less-studied interplay between these parameters in SWAN, which can substantially affect simulation accuracy and cost and is vital for the next step long-term simulation of the wave energy resources. For the present study, a 3 min timestep and three iterations are optimum. The “Garden Sprinkling” effect and the cut-off frequency were also investigated. Using 36 directional bins and a larger cut-off frequency (1.0 Hz) enable the best agreement between the model simulation and the in situ wave observations. This subsequently leads to improved model skill and performance in resolving the observed International Electrotechnical Commission (IEC) wave energy resource parameters that are highly non-linear functions of wave spectral moments.}, journal={OCEAN ENGINEERING}, publisher={Elsevier BV}, author={Allahdadi, Mohammad Nabi and He, Ruoying and Ahn, Seongho and Chartrand, Chris and Neary, Vincent S.}, year={2021}, month={Sep} }
 @article{ahn_neary_allahdadi_he_2021, title={Nearshore wave energy resource characterization along the East Coast of the United States}, volume={172}, ISBN={1879-0682}, DOI={10.1016/j.renene.2021.03.037}, abstractNote={A feasibility level nearshore wave energy resource characterization is conducted for the East Coast of the United States using a 32-year (1979–2010) hindcast from a high-resolution unstructured-grid Simulating Waves Nearshore (SWAN) model with a spatial resolution of 200 m along the coastline. Wave energy resource attributes including wave energy potentials, seasonal variability, frequency and directional spreading, and extreme sea states are characterized using a broad range of resource parameters from which opportunities, risks, and constraints for wave energy conversion (WEC) projects are assessed. Cross-shore and alongshore variations of these parameters due to varying wave energy climate and coastline orientation relative to the dominant wave systems are examined. The present study also introduces a zero-crossing method for delineating wave energy climate regions based on a broad range of resource attributes beyond just wave power. Applying this method, eight nearshore wave energy climate regions are delineated for the East Coast; each region with a unique set of resource attributes to inform regional energy planning, WEC project development, conceptual WEC design, and the operation and maintenance of WEC projects.}, journal={RENEWABLE ENERGY}, author={Ahn, Seongho and Neary, Vincent S. and Allahdadi, Mohammad Nabi and He, Ruoying}, year={2021}, month={Jul}, pages={1212–1224} }
 @article{koohestani_allahdadi_chaichitehrani_2021, title={Oceanic Response to Tropical Cyclone Gonu (2007) in the Gulf of Oman and the Northern Arabian Sea: Estimating Depth of the Mixed Layer Using Satellite SST and Climatological Data}, volume={9}, ISSN={["2077-1312"]}, DOI={10.3390/jmse9111244}, abstractNote={The category 5-equivalent tropical Cyclone Gonu (2007) was the strongest cyclone to enter the northern Arabian Sea and Gulf of Oman. The impact of this cyclone on the sea surface temperature (SST) cooling and deepening of the mixed layer was investigated herein using an optimally interpolated (OI) cloud-free sea surface temperature (SST) dataset, climatological profiles of water temperature, and data from Argo profilers. SST data showed a maximum cooling of 1.7–6.5 °C during 1–7 June 2007 over the study area, which is similar to that of slow- to medium-moving cyclones in previous studies. The oceanic heat budget equation with the assumptions of the dominant turbulent mixing effect was used to establish relationships between SST and mixed layer depth (MLD) for regions that were directly affected by cyclone-induced turbulent mixing. The relationships were applied to the SST maps from satellite to obtain maps of MLD for 1–7 June, when Gonu was over the study area. Comparing with the measured MLD from Argo data showed that this approach estimated the MLDs with an average error of 15%, which is an acceptable amount considering the convenience of this approach in estimating MLD and the simplifications applied in the heat budget equation. Some inconsistencies in calculating MLD were attributed to use of climatological temperature profiles that may not have appropriately represented the pre-cyclone conditions due to pre-existing cold/warm core eddies. Estimation of the diapycnal diffusion that quantified the turbulent mixing across the water column showed consistent temporal and spatial variations with the calculated MLDs.}, number={11}, journal={JOURNAL OF MARINE SCIENCE AND ENGINEERING}, author={Koohestani, Kamran and Allahdadi, Mohammad Nabi and Chaichitehrani, Nazanin}, year={2021}, month={Nov} }
 @article{neary_ahn_seng_allahdadi_wang_yang_he_2020, title={Characterization of Extreme Wave Conditions for Wave Energy Converter Design and Project Risk Assessment}, volume={8}, ISSN={["2077-1312"]}, DOI={10.3390/jmse8040289}, abstractNote={Best practices and international standards for determining n-year return period extreme wave (sea states) conditions allow wave energy converter designers and project developers the option to apply simple univariate or more complex bivariate extreme value analysis methods. The present study compares extreme sea state estimates derived from univariate and bivariate methods and investigates the performance of spectral wave models for predicting extreme sea states at buoy locations within several regional wave climates along the US East and West Coasts. Two common third-generation spectral wave models are evaluated, a WAVEWATCH III® model with a grid resolution of 4 arc-minutes (6–7 km), and a Simulating WAves Nearshore model, with a coastal resolution of 200–300 m. Both models are used to generate multi-year hindcasts, from which extreme sea state statistics used for wave conditions characterization can be derived and compared to those based on in-situ observations at National Data Buoy Center stations. Comparison of results using different univariate and bivariate methods from the same data source indicates reasonable agreement on average. Discrepancies are predominantly random. Large discrepancies are common and increase with return period. There is a systematic underbias for extreme significant wave heights derived from model hindcasts compared to those derived from buoy measurements. This underbias is dependent on model spatial resolution. However, simple linear corrections can effectively compensate for this bias. A similar approach is not possible for correcting model-derived environmental contours, but other methods, e.g., machine learning, should be explored.}, number={4}, journal={JOURNAL OF MARINE SCIENCE AND ENGINEERING}, author={Neary, Vincent S. and Ahn, Seongho and Seng, Bibiana E. and Allahdadi, Mohammad Nabi and Wang, Taiping and Yang, Zhaoqing and He, Ruoying}, year={2020}, month={Apr} }
 @article{dye_jose_allahdadi_2020, title={Circulation Dynamics and Seasonal Variability for the Charlotte Harbor Estuary, Southwest Florida Coast}, volume={36}, ISSN={["1551-5036"]}, DOI={10.2112/JCOASTRES-D-19-00071.1}, abstractNote={Dye, B.; Jose, F., and Allahdadi, M.N., 2020. Circulation dynamics and seasonal variability for the Charlotte Harbor Estuary, Southwest Florida coast. Journal of Coastal Research, 36(2), 276–288. Coconut Creek (Florida), ISSN 0749-0208.A hydrodynamic model was developed and validated for the Charlotte Harbor estuarine system, located in SW Florida, to elucidate freshwater fluxes within the system's various inlets during diverse hydrologic conditions. Fresh water entering the system not only varies seasonally but also, because of regulatory fresh water, releases controlling water levels within an upstream lake. The unnatural freshwater releases have been found to negatively affect the system's ecology, in particular within the Caloosahatchee River portion of the system. Neither the flood nor ebb phase exhibits uniform dominance in flushing the system's four major passes. Boca Grande Pass and Big Carlos Pass were mostly ebb dominant, whereas San Carlos Bay was largely flood dominant; neither phase dominated at Captiva Pass. The similarities and/or contradictions of these results in comparison to former field and modeling results are mainly attributed to the differences between the freshwater sources and environmental forces corresponding to each study that forces a different mass-balance condition over the estuary-bay system and, thereby, at each individual inlet. A Lagrangian particle tracking study revealed particles released within the Peace River during different hydrological conditions were comparably transported regardless of freshwater inputs and predominate wind direction. In contrast, particles released within the Caloosahatchee River were flushed into the Gulf of Mexico within 10 days during a usually wet El Niño, dry (November–April) season period whereas during the summer wet (May–October) season released particles remained in the estuary for a longer period (13 days), ultimately resulting in their further transport into Pine Island Sound and Matlacha Pass. The results also demonstrate the effect of freshwater river inputs and wind on the travel time of the neutrally buoyant particles within the estuarine system. The hydrodynamic and coupled particle tracking model serve as the first step in a forthcoming larval transport modeling study.}, number={2}, journal={JOURNAL OF COASTAL RESEARCH}, author={Dye, Bass and Jose, Felix and Allahdadi, Mohammad Nabi}, year={2020}, month={Mar}, pages={276–288} }
 @article{chaichitehrani_li_xu_allahdadi_hestir_keim_2019, title={A numerical study of sediment dynamics over Sandy Point dredge pit, west flank of the Mississippi River, during a cold front event}, volume={183}, ISSN={["1873-6955"]}, DOI={10.1016/j.csr.2019.06.009}, abstractNote={Sediment transport over Sandy Point dredge pit in the northern Gulf of Mexico during a cold front event in November 2014 was examined using a finely resolved numerical model. The Delft3D model was used to perform numerical experiments that simulate the effect of wind-generated waves, wind-driven currents, river discharge, and tides on sediment dynamics in Sandy Point dredge pit. The hydrodynamics and sediment models were validated and calibrated using field data of current, wave, water level, and suspended sediment concentration. Two potential sources of sediment were examined: fluvial sediment from the Mississippi River and resuspended sediments from the seabed. Results showed that during a cold front, shear stress from wave motions played a significant role in the resuspension of sediments in Sandy Point dredge pit. The maximum cold front-related wave impact on sediment resuspension could increase near-bed sediment concentration in Sandy Point dredge pit by 20–50 times. In addition, the results suggest that the primary source of sediment for Sandy Point dredge pit during a cold front was resuspension from the ambient seabed due to increased bottom shear stress by wind-induced waves and strong southward wind-driven currents. Currents dispersed sediments from the Mississippi River passes and inhibited riverine sediment supply from Sandy Point dredge pit. Results also showed that cold fronts contribute 16%–24% of the annual sedimentation in Sandy Point dredge pit.}, journal={CONTINENTAL SHELF RESEARCH}, author={Chaichitehrani, Nazanin and Li, Chunyan and Xu, Kehui and Allahdadi, Mohammad Nabi and Hestir, Erin L. and Keim, Barry D.}, year={2019}, month={Jul}, pages={38–50} }