Empirical Determination Research Articles

Empirical determination of sustainable withdrawal rates considering historical yields and inflation rates in Germany

On account of the current low interest rate phase, which is most likely to continue in the coming years, the average yields to be achieved in the bond, time deposit and savings product sectors are declining, so that risk-averse investors in particular have few opportunities to generate return-oriented retirement provisions.This scientific article analyzes the level of a possible safe withdrawal rate for diversified pension portfolios, considering historical returns and inflation rates. Consequently, this article provides immediate practical added value for a possible retirement provision.The evaluation is based on the consideration of historical returns of the stock and bond market in Germany. To determine a safe withdrawal rate, the development of portfolios with different compositions and inflation-adjusted withdrawal rates are simulated over periods of 15 to 35 years. In this simulation, the risky part of the portfolio is represented by German equities, the low risk part by German government bonds.To sum up, the empirical results show a maximum safe withdrawal rate of 4%. The underlying portfolio is composed of 50% equities and 50% government bonds. Particularly due to the outlined demographic change in Germany as well as the ongoing low-interest phase, the empirical study can provide significant theoretical and practical insights.

Calibration of bias and scatter involved in cluster mass measurements using optical weak gravitational lensing

ABSTRACT Cosmological inference from cluster number counts is systematically limited by the accuracy of the mass calibration, i.e. the empirical determination of the mapping between cluster selection observables and halo mass. In this work we demonstrate a method to quantitatively determine the bias and uncertainties in weak-lensing (WL) mass calibration. To this end, we extract a library of projected matter density profiles from hydrodynamical simulations. Accounting for shear bias and noise, photometric redshift uncertainties, mis-centreing, cluster member contamination, cluster morphological diversity, and line-of-sight projections, we produce a library of shear profiles. Fitting a one-parameter model to these profiles, we extract the so-called WL mass MWL. Relating the WL mass to the halo mass from gravity-only simulations with the same initial conditions as the hydrodynamical simulations allows us to estimate the impact of hydrodynamical effects on cluster number counts experiments. Creating new shear libraries for ∼1000 different realizations of the systematics provides a distribution of the parameters of the WL to halo mass relation, reflecting their systematic uncertainty. This result can be used as a prior for cosmological inference. We also discuss the impact of the inner fitting radius on the accuracy, and determine the outer fitting radius necessary to exclude the signal from neighbouring structures. Our method is currently being applied to different Stage III lensing surveys, and can easily be extended to Stage IV lensing surveys.

The permanent tide and the International Height Reference Frame IHRF

The International Height Reference System (IHRS), adopted by International Association of Geodesy (IAG) in its Resolution No. 1 at the XXVI General Assembly of the International Union of Geodesy and Geophysics (IUGG) in Prague in 2015, contains two novelties. Firstly, the mean-tide concept is adopted for handling the permanent tide. While many national height systems continue to apply the mean-tide concept, this was the first time that the IAG officially introduced it for a potential field quantity. Secondly, the reference level of the height system is defined by the equipotential surface where the geopotential has a conventional value W0 = 62,636,853.4 m2 s–2. This value was first determined empirically to provide a good approximation to the global mean sea level and then adopted as a reference value by convention. I analyse the tidal aspects of the reference level based on W0. By definition, W0 is independent of the tidal concept that was adopted for the equipotential surface, but for different concepts, different functions are involved in the W of the equation W = W0. I find that, in the empirical determination of the adopted estimate W0, the permanent tide is treated inconsistently. However, the consistent estimate from the same data rounds off to the same value. I discuss the tidal conventions and formulas for the International Height Reference Frame (IHRF) and the realisation of the IHRS. I propose a simplified definition of IHRF geopotential numbers that would make it possible to transform between the IHRF and zero-tide geopotential numbers using a simple datum-difference surface. Such a transformation would not be adequate if rigorous mean-tide formulas were imposed. The IHRF should adopt a conventional (best) estimate of the permanent tide-generating potential, such as that which is contained in the International Earth Rotation and Reference Systems Service Conventions, and use it as a basis for other conventional formulas. The tide-free coordinates of the International Terrestrial Reference Frame and tide-free Global Geopotential Models are central in the modelling of geopotential for the purposes of the IHRF. I present a set of correction formulas that can be used to move to the zero-tide model before, during, or after the processing, and finally to the mean-tide IHRF. To reduce the confusion around the multitude of tidal concepts, I propose that modelling should primarily be done using the zero-tide concept, with the mean-tide potential as an add-on. The widespread use of the expression “systems of permanent tide” may also have contributed to the confusion, as such “systems” do not have the properties that are generally associated with other “systems” in geodesy. Hence, this paper mostly uses “concept” instead of “system” when referring to the permanent tide.

Empirical Determinants of Corruption in Honduran Municipalities

This article evaluates municipal bureaucratic corruption in Honduras on a sample of 268 observations of Honduran municipalities surveyed by the Latin-American Public Opinion Poll for 2004–2016. This bureaucratic corruption is measured by officials’ request for a bribe from citizens to get some municipal paperwork done. Financial factors do not impact corruption. Officials could take advantage of citizens’ imperfect information (agency problem) to obtain personal benefits and extract income through certain expenditures that allow them to hide corruption. In this regard, Supreme Audit Institution audits refrain officials from incurring corrupt practices by counteracting the agency problem. Accordingly, audit reports should be presented to the municipal council and citizens through open councils. Implementation of digital government would contribute to curbing corruption, as it would minimize officials’ contact with citizens and, consequently, bribery.

An Empirical Determination of the Dependence of the Circumgalactic Mass Cooling Rate and Feedback Mass Loading Factor on Galactic Stellar Mass

Abstract Using our measurements of the Hα emission line flux originating in the cool (T ∼ 104 K) gas that populates the halos of galaxies, we build a joint model to describe the mass of the cool circumgalactic medium (CGM) as a function of galactic stellar mass ( 10 9.5 < M ∗ / M ⊙ < 10 11 ) and environment. Because the Hα emission correlates with the main cooling channel for this gas, we are able to estimate the rate at which the CGM cools and becomes fuel for star formation in the central galaxy. We describe this calculation, which uses our observations, previous measurements of some critical CGM properties, and modeling of the cooling mechanism using the Cloudy modeling suite. We find that the mass cooling rate is larger than the star formation rates of the central galaxies by a factor of ∼4–90, empirically confirming that there is sufficient fuel to resolve the gas consumption problem and that feedback is needed to avoid collecting too much cold gas in galaxies. We find excellent agreement between our estimates of both the mass cooling rates and mass loading factors and the predictions of independent theoretical studies. The convergence in results that we find from several completely different treatments of the problem, particularly at the lower end of the galactic mass range, is a strong indication that we have a relatively robust understanding of the quantitative effects of feedback across this mass range.

Gene body DNA methylation in seagrasses: inter- and intraspecific differences and interaction with transcriptome plasticity under heat stress

The role of DNA methylation and its interaction with gene expression and transcriptome plasticity is poorly understood, and current insight comes mainly from studies in very few model plant species. Here, we study gene body DNA methylation (gbM) and gene expression patterns in ecotypes from contrasting thermal environments of two marine plants with contrasting life history strategies in order to explore the potential role epigenetic mechanisms could play in gene plasticity and responsiveness to heat stress. In silico transcriptome analysis of CpGO/E ratios suggested that the bulk of Posidonia oceanica and Cymodocea nodosa genes possess high levels of intragenic methylation. We also observed a correlation between gbM and gene expression flexibility: genes with low DNA methylation tend to show flexible gene expression and plasticity under changing conditions. Furthermore, the empirical determination of global DNA methylation (5-mC) showed patterns of intra and inter-specific divergence that suggests a link between methylation level and the plants’ latitude of origin and life history. Although we cannot discern whether gbM regulates gene expression or vice versa, or if other molecular mechanisms play a role in facilitating transcriptome responsiveness, our findings point to the existence of a relationship between gene responsiveness and gbM patterns in marine plants.

Empirical Determination of the Partition Function of Polyethylene Based on Its Pressure-Volume-Temperature-Entropy Isochoric Equation of State

An empirical partition function, for polyethylene (PE) was determined based on a pressure (PV )-volume (V)-temperature (TV )-entropy (SV ) isochoric equation of state where the variables of PV , TV and SV were evaluated by using the experimental P-V-T data and the isochoric heat capacity for PE . The empirical partition function is expressed by summation of the terms of and with i = 1 to 6 where the temperatures in the Boltzmann factors were in the range of= 70.5 to 423 K. The thermodynamic derivatives, such as bulk modulus, and isochoric heat capacity, CV , over a wide range of pressure were evaluated based on the two types of the partition functions derived from the isochoric equation of state and the reformed Debye partition function with and The reliability of the reformed Debye partition function was checked by the partition function calculated from the empirical isochoric equation of state.

Determination of administered activities for the treatment of Graves' disease with iodine-131: Proposition of a simplified dosimetric procedure.

This prospective study included 35 patients suffering from Graves' disease (GD) clinically and biologically confirmed by endocrinologists, sent to the nuclear medicine department of CHU de Bab El Oued, Algiers for iodine-131 therapy. CHU de Bab El Oued is a tertiary hospital located in the center of the capital Algiers. The aim of this study is to propose a simplified dosimetric procedure which will initiate iodine-131 therapy of GD in particular and hyperthyroidism in general in Niger. The determination of the maximum uptake was performed with a Biodex external probe at 2 h, 4 h, and 24 h after the administration of 3 MBq of liquid iodine-131. The iodine-131 activities were determined using the Marinelli formula with a predefined effective half-life (Te) of 5 days and subsequently extrapolated half-life with kaleidagraph software. The statistical analysis was performed using an excel sheet and analyzed using the software package Statistica 10 (stat Soft, Tulsa, USA). the male:female gender ratio was1:4.5 and the mean age was 42.56 years (±7.14). The body mass index was within normal range with a value of 25.25 kg2(±0.42) and the mean average thyroid mass was equal to 24.05 (±10.53) g. The mean uptake value at 24 h was 43.24% (±17.68%) meanwhile the maximum uptake value was 46.28 (±21.13%). The estimated effective half-life (Te) was 5.44 days (±1.96) days which were different from the predefined Te of 5 days. The mean activity determined with fixed Te and 24 h uptake was 244.45 (±109.2) MBq and the mean activity calculated with both extrapolated Te and maximum uptake was 452.22 (±381.9) MBq. Empirical determination of activity in the treatment of GD gives higher activities (1.5 times) to patients than dosimetric methods based on the determination of extrapolated effective half-life.

Combine-Net: An Improved Filter Pruning Algorithm

The powerful performance of deep learning is evident to all. With the deepening of research, neural networks have become more complex and not easily generalized to resource-constrained devices. The emergence of a series of model compression algorithms makes artificial intelligence on edge possible. Among them, structured model pruning is widely utilized because of its versatility. Structured pruning prunes the neural network itself and discards some relatively unimportant structures to compress the model’s size. However, in the previous pruning work, problems such as evaluation errors of networks, empirical determination of pruning rate, and low retraining efficiency remain. Therefore, we propose an accurate, objective, and efficient pruning algorithm—Combine-Net, introducing Adaptive BN to eliminate evaluation errors, the Kneedle algorithm to determine the pruning rate objectively, and knowledge distillation to improve the efficiency of retraining. Results show that, without precision loss, Combine-Net achieves 95% parameter compression and 83% computation compression on VGG16 on CIFAR10, 71% of parameter compression and 41% computation compression on ResNet50 on CIFAR100. Experiments on different datasets and models have proved that Combine-Net can efficiently compress the neural network’s parameters and computation.

How many trees to see the forest? Assessing the effects of morphospace coverage and sample size in performance surface analysis

Abstract Linking morphology and function is critical to understanding the evolution of organismal shape. Performance landscapes, or performance surfaces, associate empirical functional performance data with a morphospace to assess how shape variation relates to functional variation. Performance surfaces for multiple functions also can be combined to understand the functional trade‐offs that affect the morphology of a particular structure across species. However, morphological performance surfaces usually require empirical determination of performance for a number of theoretical shapes that are evenly distributed throughout the morphospace. This process is time‐consuming, and is problematic for structures that are difficult to precisely manipulate. We sought to (a) understand the degree and pattern of sampling required to produce a reliable and nuanced performance surface and (b) investigate the possibility of building a surface using only naturally occurring morphologies. To do this, we subsampled a pre‐existing set of turtle shell performance surfaces in four different ways: first, uniform subsampling of theoretical morphologies across the surface; second, random subsampling of theoretical morphologies across the surface; third, a combination uniform/random subsampling method called close‐pairs sampling and fourth, subsampling only points on the surface known to correspond to a naturally occurring turtle shell morphology. Each subset was interpolated with ordinary Kriging to produce a new performance surface for comparison to the original. We found that using a fraction of the theoretical morphologies examined in the original study (half as many or fewer) was sufficient to produce a performance surface bearing close resemblance to the original (Pearson correlation ≥0.90); close‐pairs sampling dramatically increased the power of small sample sizes. We also discovered that only sampling points on the surface corresponding to naturally occurring morphologies produced an accurate surface, but results were better when individual specimens, rather than species averages, were used. Our findings demonstrate the viability of using performance surfaces to understand the evolution of complex morphologies for which theoretical shape modelling is difficult or computationally burdensome. Both lower levels of carefully configured sampling throughout the theoretical morphospace, and development of performance surfaces using only data from naturally occurring morphologies, are acceptable alternatives to the dense theoretical shape sampling employed in previous studies. ​

Risk of Exposure to COVID-19: Visit Duration Data Can Inform Our Daily Activities Choices: An Epidemiological Investigation Using Community Mobility Data from the Metropolitan Area of Genoa, Italy.

COVID-19 spreads mainly among people who are in close contact. Policymakers mostly resorted to normative measures to limit close contacts and impose social distancing. Our study aimed to estimate the risk of exposure to COVID-19 by location and activity in crowded metropolitan areas. The risk of exposure to COVID-19 was defined as the product of crowding (people within a six feet distance) and exposure duration (fraction of 15 min). Our epidemiological investigation used aggregated and anonymized mobility data from Google Maps to estimate the visit duration. We collected visit duration data for 561 premises in the metropolitan area of Genoa, Italy from October 2020 to January 2021. The sample was then clustered into 14 everyday activities, from grocery shopping to the post office. Crowding data by activity were obtained from pre-existing building norms and new government measures to contain the pandemic. The study found significant variance in the risk of exposure to COVID-19 among activities and, for the same activity, among locations. The empirical determination of the risk of exposure to COVID-19 can inform national and local public health policies to contain the pandemic’s diffusion. Its simple numerical form can help policymakers effectively communicate difficult decisions affecting our daily lives. Most importantly, risk data by location can help us rethink our daily routine and make informed, responsible choices when we decide to go out.

Duration and competing-risks determinants of terrorist hostage-taking incidents

This paper applies survival analysis to ascertain the key empirical determinants of the duration of terrorist hostage-taking incidents during 1978–2018. Our theoretical hypotheses are primarily based on John Cross’s bargaining model where negotiation duration depends on initial negotiation spread, bargaining costs, and perceived uncertainty. For hostage events, greater initial demands of the terrorists increase incident length by augmenting the negotiation spread. Sequential release of hostages, demanding the release of imprisoned comrades, changing demands during negotiations, capturing of protected persons, and engaging in kidnappings lengthen hostage incidents by affecting bargaining costs and perceived uncertainty. The number of nonterrorists wounded and the heterogeneity of the hostage-taking squad generally reduce incident length. Based on a competing-risk analysis, we identify factors, consistent with Nash bargaining, affecting three alternative outcomes for hostage incidents.

Applying Empirical Orthogonal Function and Determination Coefficient Methods for Determining Major Contributing Factors of Satellite Sea Level Anomalies Variability in the Arabian Gulf

Gridded satellite altimetry data of the Arabian Gulf during 1993–2017 were utilized to determine the relative contributions of sea surface temperature, sea level pressure, wind speed, and evaporation reanalysis data on the variability of remotely sensed sea level anomaly (SLA), which shows a mean increasing trend of 3 mm/yr. Sea surface temperature had the strongest effect on SLA, contributing 38.40% of the variability. Sea level pressure had the second greatest effect at 17%. Wind speed did not have a significant contribution to SLA variability, while evaporation had an effect of approximately 4.13%. EOF analysis was used to determine the mode of SLA variability. The first six modes explained more than 90% of the variability in SLA. The first mode, which represents the annual signal, explains 80.30% of the variability, while the second mode resolves approximately 6.80%. The contributions of different factors on the first and second modes show that the sea surface temperature and sea level pressure dominate the influence on the annual signal. Wind speed did not show a strong effect on either annual or semiannual fluctuations, while the main contribution on the semiannual signal was due to evaporation with 9.62%.

Empirical determination of the covariance of forecast errors: An empirical justification and reformulation of hybrid covariance models

AbstractDuring the last decade, the replacement of static climatological forecast error covariance models with hybrid error covariance models that linearly combine localised ensemble covariances with static climatological error covariances has led to significant forecast improvements at several major forecasting centres. Here, a deeper understanding of why the hybrid's superficially ad hoc mix of ensemble‐based and climatological covariances yields such significant improvements is pursued. In practice, ensemble covariances are not equal to the true flow‐dependent forecast error covariance matrix. Here, the relationship between actual forecast error covariance and the corresponding ensemble covariance is empirically demonstrated. Using a simplified global circulation model and the local ensemble transform Kalman filter (LETKF), the covariance of the set of actual forecast errors corresponding to ensemble covariances close to a fixed target value is computed. By doing this for differing target values, an estimate of the actual forecast error covariance as a function of ensemble covariance is obtained. A demonstration that the hybrid is a much better approximation to this estimate than either the static climatological covariance or the localised ensemble covariance is given. The empirical estimate has two features that current hybrid error covariance models fail to represent: (i) The weight given to the static covariance matrix is an increasing function of the horizontal separation distance of the covarying model variables, and (ii) for small ensemble sizes and ensemble covariances near zero but negative, the actual forecast error covariance is a decreasing function of increasing ensemble covariance. While the first finding has been anticipated by other authors, the second finding has not been anticipated, as far as the authors are aware. Here, (ii) is hypothesised to be a consequence of spurious sample correlations and variances associated with reduced ensembles. Consistent with this hypothesis, the non‐monotonicity of this relationship is almost eliminated by quadrupling the ensemble size.

CFD Simulations of Allothermal Steam Gasification Process for Hydrogen Production

The article presents an experimental laboratory setup used for the empirical determination of the gasification of coal samples in the form of solid rock, cut out in the form of a cylinder. An experimental laboratory set enabled a series of experiments carried out at 700 °C with steam as the gasification agent. The samples were prepared from the coal seam, the use of which can be planned in future underground and ground gasification experiments. The result of the conducted coal gasification process, using steam as the gasification agent, was the syngas, including hydrogen (H2) with a concentration between 46% and 58%, carbon dioxide (CO2) with a concentration between 13% and 17%, carbon monoxide (CO) with a concentration between 7% and 11.5%, and methane(CH4) with a concentration between 9.6% and 20.1%.The results from the ex-situ experiments were compared with the results of numerical simulations using computational fluid dynamics (CFD) methods. A three-dimensional numerical model for the coal gasification process was developed using Ansys-Fluent software to simulate an ex-situ allothermal coal gasification experiment using low-moisture content hard coal under atmospheric conditions. In the numerical model, the mass exchange (flow of the gasification agent), the turbulence description model, heat exchange, the method of simulating the chemical reactions, and the method of mapping the porosity medium were included. Using the construction data of an experimental laboratory set, a numerical model was developed and its discretization (development of a numerical grid, based on which calculations are made) was carried out. Tip on the reactor, supply method, and parameters maintained during the gasification process were used to define the numerical model in the Ansys-Fluent code. A part of the data were supplemented on the basis of literature sources. Where necessary, the literature parameters were converted to the conditions corresponding to the experiment, which were carried out. After performing the calculations, the obtained results were compared with the available experimental data. The experimental and the simulated results were in good agreement, showing a similar tendency.

Development and validation of a wart-associated human papilloma virus genotyping assay for detection of HPV in cutaneous warts.

Cutaneous warts are infectious disorders caused by human papillomavirus (HPV). A recent study revealed that the HPV genotype influences the natural course and response to treatment for plantar warts, suggesting that HPV genotyping could potentially be used to optimize wart treatment schemes. For this purpose, a wart-associated HPV genotyping assay was developed. The assay was subjected to an intensive validation process including, i.a., empiric determination of the annealing temperature, primer-probe optimization, evaluation of the analytical specificity and sensitivity, viral load quantification, and qualitative as well as quantitative analysis of intra-run repeatability and inter-run reproducibility. The newly developed assay was employed in a small-scale HPV genotyping study of wart biopsies (n = 50). The assay exhibited an analytical type-specific sensitivity and specificity of 100% (95% confidence interval [CI]: 83.9%-100%). The limit of quantification of the tested sequences corresponded to less than 17 viral copies/µl, while the limit of detection was less than 5 copies/µl. Very good to excellent agreements were gained between intra- and inter-run measurements (κ = 0.85-1.00) and coefficients of variation of the quantitative agreements were less then 3%. 22.5% (95% CI: 11%-39%) of the analyzed biopsies were negative for the tested HPV types, while 35% (95% CI: 21%-52%) contained multiple infections. The wart-associated HPV quantitative polymerase chain reaction assay was proven to be highly sensitive and specific. Multiple HPV infections were detected in 35% of lesions, contradicting the current literature claiming that in immunocompetent patients only 4%-16% of warts exhibit multiple HPV infections. This assay is qualified to be implemented in development of future genotype specific wart treatment strategies.

Economic conditions, task shares, and overqualification

Abstract This article demonstrates that economic conditions affect job match quality by influencing the task shares of available jobs. Cognitive (reasoning/communication) and physical (sensory/coordination) task shares and education-based overqualification measures are generated from Canada’s Labour Force Survey, the Career Handbook, and the Occupational Information Network database. In unfavourable labour markets, cognitive task intensity decreases and physical task intensity rises. The task content of newly formed jobs is then shown to be an important empirical determinant of overqualification. A calibrated search model that accounts for these findings quantifies the costs of increased overqualification. Each percentage point increase in unemployment raises overqualification by 5.8 percentage points, partly due to changes in task shares. Economic output subsequently decreases by about 0.6%.

A transient heat and moisture transfer model for building materials based on phase change criterion under isothermal and non-isothermal conditions

In this paper, a transient model for coupled heat and moisture transfer in building materials based on phase change criterion (PCC) was built. The PCC was introduced in both the energy conservation equation and the moisture conservation equation to simplify the model. The relations between PCC and usual material hygrothermal properties under isothermal and non-isothermal conditions were both derived to evaluate the effects of relative humidity, temperature and temperature gradient on the PCC. These relations enabled solving the problems that the empirical determination of the PCC was difficult and the existing models with a constant empirical value of PCC were inaccurate. The numerical results showed that the PCC was significantly affected by the sorption capacity. The effects of relative humidity, temperature and temperature gradient on the PCC could be ignored when the relative humidity in the cellulose insulation was less than 60%, and the PCC could be taken as a constant value of 1.0 within this relative humidity range. When the relative humidity in the cellulose insulation was larger than 60%, the model with the proposed expressions of PCC was more accurate than that with an empirical value of PCC for the hygrothermal performance analysis of the material.

Disease and demographic development: the legacy of the plague

This paper provides an empirical investigation of the hypothesis that population shocks such as the repeated outbreaks of the plague affected the timing of the demographic transition. The empirical analysis uses disaggregate data from Germany and exploits geographic variation in the exposure to medieval plague shocks. The findings document that areas with greater exposure to plague outbreaks exhibited an earlier onset of the demographic transition. The results are consistent with the predictions of the unified growth literature and provide novel insights into the largely unexplored empirical determinants of the timing of the transition from stagnation to growth.

Evidence of nonlinear Walker circulation feedbacks on extreme El Niño Pacific diversity: Observations and CMIP5 models

AbstractThe Walker circulation (WC) is essential for the formation and diversity of El Niño events. However, the nonlinear WC feedback during extreme Central and Eastern El Niño episodes (C and E episodes, respectively) has received little attention. This study used observational datasets and the Atmospheric Model Intercomparison Project (AMIP) and historical simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5). Eight out of 21 historical models that simulate the El Niño‐Southern Oscillation (ENSO) nonlinearity also simulate the nonlinear Bjerknes feedback in C and E episodes. The opposite does not necessarily occur. However, the underestimation of E might limit the empirical determination. Moreover, few historical models simulate the shallow conditional instability of the second kind (CISK) mechanism. Positive C episodes feature an eastward shift in the ascending branch of the Pacific Walker cell (PWC), while shallow convection prevails over the far‐eastern Pacific (FEP). Positive E events feature two anomalous ascending branches located over the central‐western Pacific (170°W) and FEP (80°W). Positive anomalies in sea surface temperature over the FEP induce the second ascending branch. The positive stratification anomaly in the central Pacific Ocean, which is associated with overestimated Ekman feedback, limits the eastward displacement of the first ascending branch of the PWC. The net surface heat flux determines the duration of growth of the two ascending branches of the PWC during C and E events. Because of their coarse resolution, the historical models underestimate the positive stratification anomaly in the FEP, causing the quick demise of the second ascending branch.