Standard RBC Research Articles

Correlation of Sysmex-XN9000 and CellaVision Advanced RBC software on anisocytosis

ABSTRACTObjectiveThis study aims to evaluate the consistency of heterogeneity degree of erythrocyte volume parameters between the blood automated analyzer Sysmex-XN9000 and the advanced red blood cell software CellaVisionDI-60.Method500 blood samples of volunteers were analyzed by Sysmex-XN9000 and CellaVision-DI60. The sensitivity, specificity, positive predictive value, negative predictive value, false positive rate, and false negative rate were evaluated. The consistency of all parameters was tested.ResultTaking the standard RBC group as the control group, the RBC parameters of the macrocytic and the microcytic group were compared. There was a statistical difference between the groups. ROC curve analysis showed that the best cutoff value of microcytic and of macrocytic affecting MCV were 4.1% and 5.7%, respectively. The best cutoff value of anisocytosis was 15.0%. The correlation coefficient between anisocytosis and red blood cell distribution width (RDW-CV) was 0.756. The sensitivity, specificity, positive predictive value and coincidence rate of anisocytosis were high. The false negative rate was 10.0%, and the false positive rate was 7.4%.ConclusionAll parameters of the degree of heterogeneity have good accuracy and consistency in the two instruments. Anisocytosis is with higher coincidence rate and positive predictive value. MIC and MAC have a good prediction on the increase or decrease of MCV. Although advanced RBC software's false negative and false positive rates are high, the red blood cell image system is more intuitive and time-saving in observing cells. Consequently, CellaVision-DI60 is suggested to combine with XN-9000 for judging the anisocytosis in daily work comprehensively.

The inverted leading indicator property and redistribution effect of the interest rate

The interest rate at which US firms borrow funds has two features: (i) it moves in a countercyclical fashion and (ii) it is an inverted leading indicator of real economic activity: low interest rates today forecast future booms in GDP, consumption, investment, and employment. We show that a Kiyotaki–Moore model accounts for both properties when interest-rate movements are driven, in a significant way, by self-fulfilling belief shocks that redistribute income away from lenders and to borrowers during booms. The credit-based nature of such self-fulfilling equilibria is shown to be essential: the dynamic correlation between current loanable funds rate and future aggregate economic activity depends critically on the property that the interest rate is state-contingent. Bayesian estimation of our benchmark DSGE model on US data shows that the model driven by redistribution shocks results in a better fit to the data than both standard RBC models and Kiyotaki–Moore type models with unique equilibrium.

Transfusion-Associated Delirium in Children: No Difference Between Short Storage Versus Standard Issue RBCs.

Primary objective is to determine if transfusion of short storage RBCs compared with standard issue RBCs reduced risk of delirium/coma in critically ill children. Secondary objective is to assess if RBC transfusion was independently associated with delirium/coma. This study was performed in two stages. First, we compared patients receiving either short storage or standard RBCs in a multi-institutional prospective randomized controlled trial. Then, we compared all transfused patients in the randomized controlled trial with a single-center cohort of nontransfused patients matched for confounders of delirium/coma. Twenty academic PICUs who participated in the Age of Transfused Blood in Critically Ill Children trial. Children 3 days to 16 years old who were transfused RBCs within the first 7 days of admission. Subjects were randomized to either short storage RBC study arm (defined as RBCs stored for up to seven days) or standard issue RBC study arm. In addition, subjects were screened for delirium prior to transfusion and every 12 hours after transfusion for up to 3 days. Primary outcome measure was development of delirium/coma within 3 days of initial transfusion. Additional outcome measures were dose-response relationship between volume of RBCs transfused and delirium/coma, and comparison of delirium/coma rates between transfused patients and individually matched nontransfused patients. We included 146 subjects in the stage I analysis; 69 were randomized to short storage RBCs and 77 to standard issue. There was no significant difference in delirium/coma development between study arms (79.5% vs 70.1%; p = 0.184). In the stage II analysis, adjusted odds for delirium in the transfused cohort was more than eight-fold higher than in the nontransfused matched cohort, even after controlling for hemoglobin (adjusted odds ratio, 8.9; CI, 2.8-28.4; p < 0.001). RBC transfusions (and not anemia) are independently associated with increased odds of subsequent delirium/coma. However, storage age of RBCs does not affect delirium risk.

The role of endogenous capital depreciation rate for business cycle dynamics: lessons from Bulgaria (1999-2018)

&#x0D; &#x0D; &#x0D; We allow for an endogenous depreciation rate of physical capital stock into a real-business-cycle model with a government sector. We calibrate the model to Bulgarian data for the period following the introduction of the currency board arrangement (1999-2018). We investigate the quantitative importance of the endogenous depreciation rate, and indirectly, the capital utilization mechanism for cyclical fluctuations in Bulgaria. Allowing for endogenous variations in the depreciation rate of capital improves the model performance against data, and in addition this extended setup dominates the standard RBC model framework with constant depreciation and a fixed utilization rate of physical capital, and a fixed depreciation rate e.g., Vasilev (2009).&#x0D; &#x0D; &#x0D;

Gender differences in the volatility of work hours and labor demand

This paper examines the role of heterogeneity in a real business cycle model, which traditionally has not fully captured the relative volatility of hours to output. Men and women have different cyclical volatilities in hours worked, which is robust to different filtering methods. This empirical regularity is used to motivate a standard RBC model augmented to allow for two different agents following Jaimovich et al. (2013). These two agents have identical utility functions, but face different elasticities of labor demand due to their different complementarities with capital. These estimated elasticities find that women are more complementary to capital. The calibrated model generates the cyclical volatility of work hours by gender and for the total hours worked that matches the U.S. data better than the traditional representative agent model. I then explore other extensions to this model including investigating the stability of the estimated labor demand elasticities and allowing for various Frisch elasticities of labor supply. This paper demonstrates that allowing for even broad levels of heterogeneity in a simple framework can increase the model’s tractability with the data. Since gender is important to explain U.S. business cycle dynamics, we need to carefully consider heterogeneity when analyzing counter-cyclical economic policy, as it may not have symmetric effects across assorted groups.

Aggregate labor market fluctuations under news shocks

The standard RBC model fails to replicate the relationship between aggregate hours worked and average productivity. We propose a DSGE model that incorporates habit formation preferences, capital adjustment costs, and news shocks to solve the puzzle implied in the standard RBC model with only technological shocks. The aggregate labor supply curve is shifted due to the wealth effect caused by the variation of consumption under a news shock. Moreover, capital adjustment costs help amplify the variation of consumption, and thus the movement of the aggregate labor supply curve under the news shock. Also, the aggregate demand curve will be shifted, as it operates in the standard RBC model after the realization of the news shock. As a result of the joint movement of the aggregate labor supply curve and aggregate labor demand curve under the news shock, the model achieves a relationship quite close to the empirically observed relationship.

Labour market fluctuations: An RBC model for emerging countries

In this paper, we examine the labour market properties of business cycle fluctuations for a group of 15 emerging market economies (EMEs) and the US using annual data from 1970 to 2013. We find that on average, the hours worked and employment volatility (relative to output volatility) are lower, while the volatility of productivity and wages are 2–3 times higher in EMEs compared to the US. We then assess the performance of a standard RBC model and an augmented RBC model with capacity utilization, investment adjustment cost and indivisible labour with temporary and permanent productivity shocks to explain labour market facts observed in the data. We find that these models fail to explain labour market fluctuations in the business cycles of these countries, but the model with investment adjustment cost improves the performance of relative volatility of wages and hours, as well as the cyclicality of hours, compared to the standard RBC model. Lastly, we investigate the cyclical properties of the labour wedge and find that the total labour wedge (relative to output volatility) is more volatile over the business cycle in emerging economies (1.72) compared to the US (0.95). Further, fluctuations in the total labour wedge reflect the ones in the household component rather than the firm component of the wedge in EMEs and the US.

Growth and real business cycles in Vietnam and the Asean-5. Does the trend shock matter?

We examine Vietnam’s economy in comparison with its closest trade partners. We show that capital accumulation has been the primary growth engine since the start of its transition to the pro-market economy in 1986 – the Doi Moi. We also show that the cyclical behavior of its macro aggregates is similar to that of its ASEAN-5 peers and other developing countries. We extend the standard small open economy RBC model by considering habit persistence and government consumption, which allows a close match of the moments of the growth variables. At the business cycle frequency, transitory productivity shocks account for approximately one-half of Vietnam’s output variance, while country risk and non-transitory productivity shocks account to close to one-fifth each. Regarding the Solow residual’s volatility, we find that the trend component merely accounts for 12 % of this variance in Vietnam, while in Thailand it is only 6 %. These findings refute the “the cycle is the trend” hypothesis in Aguiar and Gopinath (2007) and align with the hypotheses in García-Cicco et al. (2010) and Rhee (2017), where the stationary component is overwhelmingly dominant. We claim that technological progress and productivity-enhancing measures are fundamental for Vietnam’s economy to sustain high growth.

The Role of Energy in a Real Business Cycle Model with an Endogenous Capital Utilization Rate in a Government Sector: Lessons from Bulgaria (1999–2016)

Abstract We introduce a pro-cyclical endogenous utilization rate of physical capital stock into a real business cycle model augmented with a government sector in detail. We calibrate the model to Bulgarian data for the period following the introduction of the currency board arrangement (1999–2016). We investigate the quantitative importance of the endogenous depreciation rate and the capital utilization mechanism working through the use of energy for cyclical fluctuations in Bulgaria. In particular, a positive shock to energy prices in the model works like a negative technological shock. Allowing for variations in factor utilization and the presence of energy as a factor of production improves the model performance against data, and in addition this extended setup dominates the standard RBC model framework with constant depreciation and a fixed utilization rate of physical capital (e.g., Vasilev (2009)).

Risk Weighting, Private Lending and Macroeconomic Dynamics

According to current regulation, European banks can apply zero risk weights to sovereign exposures in their balance sheet, irrespective of the assigned rating. We show that a zero risk weighting of sovereign bonds has implications by distorting banks' asset allocation decisions. Due to the lower regulatory cost of sovereign bonds, banks invest more in those bonds at the expense of lending to the real sector. To quantify the effect of this distortion, we build a standard RBC model featuring financial intermediation and a government sector calibrated to the euro area economy. Financial regulation is introduced via a penalty function that punishes banks if they deviate from the target capital ratio. We study the zero risk weight policy during normal times when there is no sovereign default risk and find that a policy introducing positive risk weights on government bonds has both long-run effects and stabilising properties with respect to the business cycle. This policy makes the steady state lending spread on loans to firms decline, stimulating investment and output. Also, it stabilises the lending spread, leading to a lower volatility of investment and output.

Eductive Stability in Real Business Cycle Models

We reexamine issues of coordination in the standard RBC model. Is the unique rational expectations equilibrium attainable by rational agents who contemplate the possibility of small deviations from equilibrium? Surprisingly, we …nd that coordination cannot be expected. Even with strong common knowledge assumptions, rational agents anticipating small but persistent deviations are led to take actions that eventually contradict the common knowledge assumption. This “impossibility”theorem for eductive learning is not fully overcome when adaptive learning is incorporated into the framework.

Expectation shocks and fiscal rules

This paper discuss expectation (or news) shocks to government expenditures: consumption or investment spending in an otherwise standard RBC model of the U.S. economy. In addition, we study the differences emerging from modelling fiscal policy with and without fiscal rules. We find that news about future fiscal policy generate dramatically different effects, if fiscal policy follows a rule. Our findings have several implications for the design and the implementation of fiscal policy as well as the estimation of fiscal shocks.

How Large Are Returns to Scale in the U.S.? A View Across the Boundary

I study the degree of returns to scale in aggregate U.S. data by estimating the standard RBC model with and without variable capacity utilization using Bayesian methods. The source of increasing returns is the presence of an externality in production. I find that, at best, returns are mildly increasing at a level statistically indistinguishable from the constant-returns case. A high enough degree of increasing returns is needed to support equilibrium indeterminacy and sunspot-driven business cycle fluctuations. In my estimation results, I find that I can conclusively rule out this possibility on account of a low estimated degree of increasing returns and a fairly inelastic labor supply.

The Inverted Leading Indicator Property and Redistribution Effect of the Interest Rate

The interest rate at which US firms borrow funds has two features: (i) it moves in a countercyclical fashion and (ii) it is an inverted leading indicator of real economic activity: low interest rates today forecast future booms in GDP, consumption, investment, and employment. We show that a Kiyotaki-Moore model accounts for both properties when interest-rate movements are driven, in a significant way, by self-fulfilling shocks that redistribute income away from lenders and to borrowers during booms. The credit-based nature of such self-fulfilling equilibria is shown to be essential: the dynamic correlation between current loanable funds rate and future aggregate economic activity depends critically on the property that the interest rate is state-contingent. Bayesian estimation of our benchmark DSGE model on US data shows that the model driven by redistribution shocks results in a better fit to the data than both standard RBC models and Kiyotaki-Moore type models with unique equilibrium.

Tuning in RBC Growth Spectra

For US postwar data, the paper explains central consumption, labor, investment and output correlations and volatilities along with output growth persistence by including a human capital investment sector and a variable physical capital utilization rate. Strong internal amplication results from an economy-wide productivity shock across goods and human capital investment sectors that has variances 10,000 fold smaller than in the standard RBC TFP shock. Simulated moments are compared to data moments for the business cycle, the low frequency and the Medium Cycle frequency, as well as the high frequency. A metric is provided to gauge that the results have an average of 46% deviation of simulated moments from data moments, for a broad array of targets across all windows. Within this array, key correlations have only a 15% deviation in the business cycle window, and growth persistence only an 8% deviation in the low frequency, which indicates good propagation. Countercyclic human capital investment time and procyclic physical capital capacity utilization rates are also found as in data.

The Inverted Leading Indicator Property and Redistribution Effect of the Interest Rate

The interest rate at which US firms borrow funds has two features: (i) it moves in a countercyclical fashion and (ii) it is an inverted leading indicator of real economic activity: low interest rates today forecast future booms in GDP, consumption, investment, and employment. We show that a Kiyotaki–Moore model accounts for both properties when interest-rate movements are driven, in a significant way, by self-fulfilling belief shocks that redistribute income away from lenders and to borrowers during booms. The credit-based nature of such self-fulfilling equilibria is shown to be essential: the dynamic correlation between current loanable funds rate and future aggregate economic activity depends critically on the property that the interest rate is state-contingent. Bayesian estimation of our benchmark DSGE model on US data shows that the model driven by redistribution shocks results in a better fit to the data than both standard RBC models and Kiyotaki–Moore type models with unique equilibrium.

Immunomodulatory Effects of Transfusion

Immunomodulation following transfusion of cellular blood products presents as a generalized immunosuppression and/or production of alloantibody. The immunological effects of transfusion in immunocompetent subjects were evaluated in patients undergoing cardiac surgery with cardio-pulmonary by-pass.Subjects were consented for this IRB-approved study and were randomized to receive unmodified (STD) red blood cells (rbc), leukoreduced (LR) rbc or LR rbc that were g-irradiated (g-I). All platelet transfusions were collected LR and they were also g-I for the third arm. Patients were transfused only when clinically indicated. Subjects receiving no transfusions during the study served as a fourth control arm. Peripheral blood samples collected prior to surgery were controls for samples collected after surgery (day 10 +/- 4 and day 30 +/-5).HLA antibody production was evaluated in 245 subjects using single-antigen multiarray assays for antibody to both HLA class I and class II, a summary of results in shown in Table 1. For subjects with HLA antibody in their pre-surgery sample, these assays allowed evaluation of change in antibody specificity or levels. For these pre-sensitized subjects, there was no significant difference in HLA antibody production between the transfused study arms: even those not transfused showed an increase, most likely due to activation of memory responses. For subjects without HLA antibody in their pre-surgery sample, recipients of LR products showed little increase supporting prior studies showing the efficacy of LR in reducing antibody. However the protection afforded by LR was abrogated by g-I. This was an unexpected finding.We evaluated cellular and cytokine mediators of immunosuppression in the first 139 consecutive subjects of the 245 subjects enrolled in this study. This part of the study was powered for hypothesis generation, not statistical significance. Mononuclear cells (MNC) were isolated from each sample, frozen, and all samples from a subject assayed together. We assayed these cells for production of TGFB1 using ELISPOT. We used flow cytometry phenotyping for markers of CD4+25+ T regulatory cells (CTLA4, FoxP3) and for intracellular cytokines for CD4+ and CD4- NKT cells (IFNG, IL-4, IL-10). As shown in Table 2, recipients of standard rbc showed an increase (following transfusion and surgery) in TGFB1 producing mononuclear cells with a lower increase in recipients of LR rbc and those who were not transfused, but further reduced in the group receiving g-I LR products. Recipients of standard rbc or of LR rbc showed an increase of T lymphocytes expressing FoxP3 or CTLA4, and of CD4+ NKT cells producing IL-4. In contrast, subjects whose LR products were g-I showed a markedly lower increase in all three measures. These data identify an increase in mediators of immunosuppression in recipients of standard rbc and LR rbc that was reduced in recipients of g-I and LR rbc and platelets. Surgery and bypass alone increased the numbers of TGFB1+ MNC and IL4+ NKT cells suggesting a role for the innate immune system in immunosuppression following transfusion.This study is the first to exam the immunomodulatory effects of transfusion by combining measurement of immunosuppression in ex vivo surrogate assays and measurement of HLA antibody production inclusive of pre-sensitized subjects. Our observations of differences in responses to blood products prepared with g-I plus LR compared to LR alone were unexpected and require confirmation. It suggests that the reduction in immunosuppressive cells and cytokines in the recipients of g-I and LR products contributed to the increased allosensitization we observed in that arm compared to recipients of LR products. It may be possible to manipulate immunomodulation after transfusion to reach a desired goal for specific patient populations. [Display omitted] [Display omitted] DisclosuresSlichter:Department of Defense: Research Funding; Terumo BCT: Research Funding; Cerus Corporation: Research Funding; Cellphire, Inc.: Research Funding; Genentech: Research Funding.

Comparing Solution Methods for a Basic RBC Model

This short article compares different solution methods for a basic RBC model (Hansen, 1985). We solve and simulate the model using two main algorithms: the methods of perturbation and projection, respectively. One novelty is that we offer a type of the hybrid method: we compute easily a second-order approximation to decision rules and use that approximation as an initial guess for finding Chebyshev polynomials. We also find that the second-order perturbation method is most competitive in terms of accuracy for standard RBC model.

Indeterminacy and sunspots in two-sector RBC models with generalized no-income-effect preferences

We analyze sunspot-driven fluctuations in the standard two-sector RBC model with moderate increasing returns to scale and generalized no-income-effect preferences à la Greenwood, Hercovitz and Huffman [13]. We provide a detailed theoretical analysis enabling us to derive relevant bifurcation loci and to characterize the steady-state local stability properties as a function of various structural parameters. We show that local indeterminacy occurs through flip and Hopf bifurcations for a large set of values for the elasticity of intertemporal substitution in consumption, provided that the labor supply is sufficiently inelastic. Finally, we provide a detailed quantitative analysis of the model. Computing, on a quarterly basis, a new set of empirical moments related to two broadly defined consumption and investment sectors, we are able to identify, among the set of admissible calibrations consistent with sunspot equilibria, the ones that provide the best fit of the data. The model properly calibrated solves several empirical puzzles traditionally associated with two-sector RBC models.

Longer RBC storage duration is associated with increased postoperative infections in pediatric cardiac surgery.

Infants and children undergoing open heart surgery routinely require multiple RBC transfusions. Children receiving greater numbers of RBC transfusions have increased postoperative complications and mortality. Longer RBC storage age is also associated with increased morbidity and mortality in critically ill children. Whether the association of increased transfusions and worse outcomes can be ameliorated by use of fresh RBCs in pediatric cardiac surgery for congenital heart disease is unknown. One hundred and twenty-eight consecutively transfused children undergoing repair or palliation of congenital heart disease with cardiopulmonary bypass who were participating in a randomized trial of washed versus standard RBC transfusions were evaluated for an association of RBC storage age and clinical outcomes. To avoid confounding with dose of transfusions and timing of infection versus timing of transfusion, a subgroup analysis of patients only transfused 1-2 units on the day of surgery was performed. Mortality was low (4.9%) with no association between RBC storage duration and survival. The postoperative infection rate was significantly higher in children receiving the oldest blood (25-38 d) compared with those receiving the freshest RBCs (7-15 d) (34% vs 7%; p = 0.004). Subgroup analysis of subjects receiving only 1-2 RBC transfusions on the day of surgery (n = 74) also demonstrates a greater prevalence of infections in subjects receiving the oldest RBC units (0/33 [0%] with 7- to 15-day storage; 1/21 [5%] with 16- to 24-day storage; and 4/20 [20%] with 25- to 38-day storage; p = 0.01). In multivariate analysis, RBC storage age and corticosteroid administration were the only predictors of postoperative infection. Washing the oldest RBCs (> 27 d) was associated with a higher infection rate and increased morbidity compared with unwashed RBCs. Longer RBC storage duration was associated with increased postoperative nosocomial infections. This association may be secondary in part, to the large doses of stored RBCs transfused, from single-donor units. Washing the oldest RBCs was associated with increased morbidity, possibly from increased destruction of older, more fragile erythrocytes incurred by washing procedures. Additional studies examining the effect of RBC storage age on postoperative infection rate in pediatric cardiac surgery are warranted.