A Non-linear Approach with Long Range Dependence based on Chebyshev Polynomials

This paper examines the interaction between non-linear deterministic trends and long run dependence by means of employing Chebyshev time polynomials and assuming that the detrended series displays long memory with the pole or singularity in the spectrum occurring at one or more possibly non-zero frequencies. The combination of the non-linear structure with the long memory framework produces a model which is linear in parameters and therefore it permits the estimation of the deterministic terms by standard OLS-GLS methods. Moreover, we present a procedure that permits us to test (possibly fractional) orders of integration at various frequencies in the presence of the Chebyshev trends with no effect on the standard limit distribution of the method. Several Monte Carlo experiments are conducted and the results indicate that the method performs well, and an empirical application, using data of real exchange rates is also carried out at the end of the article

Oil shocks on unemployment in Central and Eastern Europe

The aim of this paper is to shine some light on the effect of oil price movements on unemployment in Central and Eastern Europe. In order to do so, we disentangle oil prices movements by their sign. From there we analyse the separate effect of positive and negative movements of oil prices on unemployment rates. We find that although oil prices and unemployment are not very much correlated in the short run, the effect of oil price shocks on the natural rate of unemployment goes in the same direction, i.e. increases or decreases in oil prices increase or decrease the natural rate of unemployment

Smooth transitions, asymmetric adjustment and unit roots

The aim of this article is to develop a unit root test that takes into account two sources of nonlinearites in data, i.e. asymmetric speed of mean reversion and structural changes. The asymmetric speed of mean reversion is modelled by means of a exponential smooth transition autoregression (ESTAR) function for the autoregressive parameter, whereas structural changes are approximated by a smooth transition in the deterministic components. We find that the proposed test performs well in terms of size and power, in particular when the autoregressive parameter is near unity

Socioeconomic inequalities in low birth weight risk before and during the COVID-19 pandemic in Argentina: A cross-sectional study

Background: The coronavirus disease 2019 (COVID-19) pandemic may have exacerbated existing socioe- conomic inequalities in health. In Argentina, public hospitals serve the poorest uninsured segment of the population, while private hospitals serve patients with health insurance. This study aimed to assess whether socioeconomic inequalities in low birth weight (LBW) risk changed during the first wave of the COVID-19 pandemic. Methods: This multicenter cross-sectional study included 15929 infants. A difference-in-difference (DID) analysis of socioeconomic inequalities between public and private hospitals in LBW risk in a pandemic cohort (March 20 to July 19, 2020) was compared with a prepandemic cohort (March 20 to July 19, 2019) by using medical records obtained from ten hospitals. Infants were categorized by weight as LBW < 2500 g, very low birth weight (VLBW) < 1500 g and extremely low birth weight (ELBW) < 1000 g. Log binomial regression was performed to estimate risk differences with an interaction term representing the DID estimator. Covariate-adjusted models included potential perinatal confounders. Findings: Of the 8437 infants in the prepandemic cohort, 4887 (57 ? 9%) were born in public hospitals. The pandemic cohort comprised 7492 infants, 4402 (58 ? 7%) of whom were born in public hospitals. The DID estimators indicated no differences between public versus private hospitals for LBW risk ( −1 ? 8% [95% CI −3 ? 6, 0 ? 0]) and for ELBW risk ( −0 ? 1% [95% CI −0 ? 6, 0 ? 3]). Significant differences were found between public versus private hospitals in the DID estimators ( −1 ? 2% [95% CI, −2 ? 1, −0 ? 3]) for VLBW risk. The results were comparable in covariate-adjusted models. Interpretation: In this study, we found evidence of decreased disparities between public and private hos- pitals in VLBW risk. Our findings suggest that measures that prioritize social spending to protect the most vulnerable pregnant women during the pandemic contributed to better birth outcomes. Funding: No funding was secured for this study.Fil: Cuestas, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Ciencias de la Salud. Universidad Nacional de Córdoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Gómez Flores, Martha E.. Gobierno de la Provincia de Buenos Aires. Hospital Doctor Ramón Carrillo; ArgentinaFil: Charras, María D.. Gobierno de la Provincia de Buenos Aires. Hospital Doctor Ramón Carrillo; ArgentinaFil: Peyrano, Alberto J.. Hospital Materno Provincial Dr. Raúl Felipe Lucini; ArgentinaFil: Montenegro, Clara. Hospital Materno Provincial Dr. Raúl Felipe Lucini; ArgentinaFil: Sosa Boye, Ignacio. No especifíca;Fil: Burgos, Verónica. Universidad Católica de Córdoba. Facultad de Medicina. Clínica Universitaria Reina Fabiola; ArgentinaFil: Giusti, Graciela. Clínica y Maternidad del Sol; ArgentinaFil: Espósito, Mario. Clínica y Maternidad del Sol; ArgentinaFil: Blanco Pool, Silvyana S.. Hospital Misericordia Nuevo Siglo ; Gobierno de la Provincia de Cordoba; ArgentinaFil: Gurevich, Debora P.. Hospital Misericordia Nuevo Siglo ; Gobierno de la Provincia de Cordoba; ArgentinaFil: Ahumada, Luis A.. Hospital Misericordia Nuevo Siglo ; Gobierno de la Provincia de Cordoba; ArgentinaFil: Pontoriero, Ricardo D.. Hospital Misericordia Nuevo Siglo ; Gobierno de la Provincia de Cordoba; ArgentinaFil: Rizzotti, Alina. Hospital Privado Universitario de Córdoba; ArgentinaFil: Bas, José I.. Hospital Privado Universitario de Córdoba; ArgentinaFil: Vaca, María B.. Hospital Universitario de Maternidad y Neonatología; ArgentinaFil: Miranda, María J.. Hospital Universitario de Maternidad y Neonatología; ArgentinaFil: Ferreyra, Mirta E.. Hospital Misericordia Nuevo Siglo ; Gobierno de la Provincia de Cordoba; ArgentinaFil: Moreno, Gabriela C.. Gobierno de la Provincia de Buenos Aires. Hospital Doctor Ramón Carrillo; ArgentinaFil: Pedicino, Héctor. Hospital Italiano; ArgentinaFil: Rojas Rios, Melvy. Hospital Italiano; Argentin

Association between COVID-19 mandatory lockdown and decreased incidence of preterm births and neonatal mortality

Previous studies suggest a decrease in preterm births (PTB) during de coronavirus disease 2019 (COVID-19), possibly due to the effect of the mandatory lockdown. Nevertheless, other reports have been unable to confirm this finding. Most of these studies originated in high-income countries and evaluated a limited number of potential confounders, and all of them assessed a short lockdown period. In addition, an important question remains unanswered: How can we be sure that the observed changes are due to lockdown, when most of the pregnancies delivered in the lockdown period were conceived prior to it?To date there is insufficient evidence to support the notion that public health interventions during the lockdown prevent PTB . The aim of this study was to compare the incidence of PTB, neonatal mortality (NM) and stillbirths adjusted by potential confounders during the lockdown period assessing a time window of nine and a half months during which all the pregnancies analyzed in the exposed group were conceived after the lockdown, with the corresponding incidence in the previous year where all the unexposed pregnancies analyzed were conceived before the lockdown.publishedVersionFil: Cuestas, Eduardo. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas; Argentina.Fil: Cuestas, Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ciencias de la Salud; Argentina.Fil: Gómez Flores, Martha E. Gobierno de la Provincia de Buenos Aires. Hospital Doctor Ramon Carrillo; Argentina.Fil: Charras, María D. Gobierno de la Provincia de Buenos Aires. Hospital Doctor Ramon Carrillo; Argentina.Fil: Peyrano, Alberto J. Hospital Materno Provincial Dr. Raúl Felipe Lucini; Argentina.Fil: Montenegro, Clara. Hospital Materno Provincial Dr. Raúl Felipe Lucini; Argentina.Fil: Sosa-Boye, Ignacio. Clínica Universitaria Reina Fabiola; Argentina.Fil: Burgos, Verónica. Clínica Universitaria Reina Fabiola; Argentina.Fil: Giusti, Graciela. Clínica y Maternidad del Sol; Argentina.Fil: Espósito, Mario. Clínica y Maternidad del Sol; Argentina.Fil: Blanco Pool, Silvyana S. Hospital Misericordia Nuevo Siglo; Argentina.Fil: Blanco Pool, Silvyana S. Sanatorio Allende; Argentina.Fil: Gurevich, Debora P. Sanatorio Allende; Argentina.Fil: Gurevich, Debora P. Hospital Misericordia Nuevo Siglo; Argentina.Fil: Ahumada, Luis A. Sanatorio Allende; Argentina.Fil: Ahumada, Luis A. Hospital Misericordia Nuevo Siglo; Argentina.Fil: Pontoriero, Ricardo D. Hospital Misericordia Nuevo Siglo; Argentina.Fil: Rizzotti, Alina. Hospital Privado Universitario de Córdoba; Argentina.Fil: Bas, José I. Hospital Privado Universitario de Córdoba; Argentina.Fil: Vaca, María B. Hospital Universitario de Maternidad y Neonatología; Argentina.Fil: Miranda, María J. Hospital Universitario de Maternidad y Neonatología; Argentina.Fil: Ferreyra, Mirta E. Sanatorio del Salvador; Argentina.Fil: Ferreyra, Mirta E. Hospital Misericordia Nuevo Siglo; Argentina.Fil: Moreno, Gabriela C. Sanatorio del Salvador; Argentina.Fil: Pedicino, Héctor. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentina.Fil: Rojas-Rios, Melvy. Instituto Universidad Escuela de Medicina del Hospital Italiano; Argentina