Forecasting Monetary Policy Rules in South Africa

This paper is the .rst one to: (i) provide in-sample estimates of linear and nonlinear Taylor rules augmented with an indicator of .nancial stability for the case of South Africa, (ii) analyse the ability of linear and nonlinear monetary policy rule speci.cations as well as nonparametric and semiparametric models in forecasting the nominal interest rate setting that describes the South African Reserve Bank (SARB) policy decisions. Our results indicate, .rst, that asset prices are taken into account when setting interest rates; second, the existence of nonlinearities in the monetary policy rule; and third, forecasts constructed from combinations of all models perform particularly well and that there are gains from semiparametric models in forecasting the interest rates as the forecasting horizon lengthens.

What is the redshift of the gamma- ray BL Lac source S4 0954+65?

High signal-to-noise ratio spectroscopic observations of the BL Lac object S4 0954+65 at the alleged redshift z = 0.367 are presented. This source was detected at gamma frequencies by MAGIC (TeV) and FERMI (GeV) telescopes during a remarkable outburst that occurred in February 2015, making the determination of its distance particularly relevant for our understanding of the properties of the Extragalactic Background Light. Contrary to previous reports on the redshift, we found that the optical spectrum is featureless at an equivalent width limit of \sim 0.1 Ang. A critical analysis of the existing observations indicates that the redshift is still unknown. Based on the new data we estimate a lower limit to the redshift at z \geq 0.45.Comment: Minor comment and accepted for publication in Astronomical Journa

Dyslexia and Comorbid Dyscalculia: rate of comorbidity and underlying cognitive and learning profile

PURPOSE OF THE STUDY. Children diagnosed with a specific learning disorder (SLD) have four to five times higher chances of developing a comorbid condition. In particular, the high prevalence of comorbid dyscalculia (MD) in children with dyslexia (RD) has been documented. Nevertheless, the exact rate of MD comorbidity and the causes underlying the overlap remain unclear since most research has focused on studying them in isolation. Given the relevance of early identification and evidence-based interventions for further compensation of SLD, there is a need for studies on this matter. The study intended to fill this gap. METHOD. The study was a secondary data analysis of the standardised test scores of 215 neuropsychological assessments administered to grade 1 to 3 schoolchildren in Argentina who had a prior diagnosis of RD. For the purposes of the study, they were classified into 2 groups (RD only and comorbid RDMD). Scores were analyzed using SPSS Statistics to (i) explore the rate of MD comorbidity in children with RD; (ii) contrast the cognitive and learning profiles of the RD and the RDMD group; and (iii) assess the predictive value of each cognitive factor to the development of the RDMD comorbidity. RESULTS AND CONCLUSION. The study found that children with RD developed RDMD at a frequency of 33.5%. There was a significant difference in the two groups' learning and cognitive factors scores, with the comorbid group worst affected in all domains. Among these, verbal working memory, spatial skills, semantic long-term memory and phonological awareness were the most sensitive predictors; together they could account for 35% of the MD comorbidity. These findings are evidence of the high incidence of MD comorbidity in the population with RD and highlight the predictive value of specific cognitive markers

A new methodology using beam elements for the analysis of steel frames subjected to non-uniform temperatures due to fires

[EN] Non-uniform heating in structures under fire involves the appearance of 3D-phenomena and typically requires the use of complex models built with finite elements shell or solid. Although different procedures have been developed to model the complex thermo-mechanical phenomenon, there is no simple, accurate, and low-cost computational methodology involving the space-time variation of the temperature and displacement fields that opens the path advancing more easily towards modeling more complex structural problems in a fire situation. To overcome this knowledge-gap, this paper presents a new methodology that fulfills those conditions, making it possible to carry out more complex analyses that require many simulations in a short time and at low computational costs. The new methodology to obtain the thermo-mechanical response to non-uniform heating and mechanical loads is general, simple, accurate, and avoids using complex and high-cost finite elements, simplifying the structural modeling, and reducing the computational analysis cost. As a result, complex structural fire engineering problems such as probabilistic and optimization analysis can be handled much more easily, representing a significant step toward the generalized application of performance-based approaches to deal with fire effects on structures. The procedure uses simple but advanced Timoshenko¿s beam-type finite elements and represents the non-uniform temperature space-time field through a mean value of the temperature and the two mean values of the section thermal gradients which are variable in time during the fire. The methodology is satisfactorily validated with results (experimental and numerical) of the Cardington frame test and captures 3D-phenomena such as buckling, flexural-torsional buckling, and warping.Thanks are due to the Fundación Carolina, the Universitat Politècnica de València, and the Universidad Surcolombiana for the support given to this research through the 2018-2019 Ph.D. scholarship.Pallares-Muñoz, MR.; Paya-Zaforteza, I.; Hospitaler Pérez, A. (2021). A new methodology using beam elements for the analysis of steel frames subjected to non-uniform temperatures due to fires. Structures. 31:462-483. https://doi.org/10.1016/j.istruc.2021.02.008S46248331Shan, S., & Li, S. (2020). Fire-induced progressive collapse mechanisms of steel frames with partial infill walls. Structures, 25, 347-359. doi:10.1016/j.istruc.2020.03.023Shakib, H., Zakersalehi, M., Jahangiri, V., & Zamanian, R. (2020). Evaluation of Plasco Building fire-induced progressive collapse. Structures, 28, 205-224. doi:10.1016/j.istruc.2020.08.058Horová, K., Jána, T., & Wald, F. (2013). Temperature heterogeneity during travelling fire on experimental building. Advances in Engineering Software, 62-63, 119-130. doi:10.1016/j.advengsoft.2013.05.001Xu, L., & Zhuang, Y. (2012). Storey-based stability of unbraced steel frames at elevated temperature. Journal of Constructional Steel Research, 78, 79-87. doi:10.1016/j.jcsr.2012.06.010Jacques, L., Béchet, E., & Kerschen, G. (2017). Finite element model reduction for space thermal analysis. Finite Elements in Analysis and Design, 127, 6-15. doi:10.1016/j.finel.2017.01.001B.D. R, M. SK. Behaviour of steel columns with realistic boundary restraints under standard fire. Structures 2020;28:626–37. https://doi.org/https://doi.org/10.1016/j.istruc.2020.08.028.Alos-Moya, J., Paya-Zaforteza, I., Hospitaler, A., & Loma-Ossorio, E. (2019). Valencia bridge fire tests: Validation of simplified and advanced numerical approaches to model bridge fire scenarios. Advances in Engineering Software, 128, 55-68. doi:10.1016/j.advengsoft.2018.11.003Jeffers, A. E., & Beata, P. A. (2014). Generalized shell heat transfer element for modeling the thermal response of non-uniformly heated structures. Finite Elements in Analysis and Design, 83, 58-67. doi:10.1016/j.finel.2014.01.003Rigobello, R., Coda, H. B., & Munaiar Neto, J. (2014). A 3D solid-like frame finite element applied to steel structures under high temperatures. Finite Elements in Analysis and Design, 91, 68-83. doi:10.1016/j.finel.2014.07.005Alos-Moya, J., Paya-Zaforteza, I., Hospitaler, A., & Rinaudo, P. (2017). Valencia bridge fire tests: Experimental study of a composite bridge under fire. Journal of Constructional Steel Research, 138, 538-554. doi:10.1016/j.jcsr.2017.08.008Peris-Sayol, G., Paya-Zaforteza, I., Alos-Moya, J., & Hospitaler, A. (2015). Analysis of the influence of geometric, modeling and environmental parameters on the fire response of steel bridges subjected to realistic fire scenarios. Computers & Structures, 158, 333-345. doi:10.1016/j.compstruc.2015.06.003Quiel, S. E., Moreyra Garlock, M. E., & Paya-Zaforteza, I. (2011). Closed-Form Procedure for Predicting the Capacity and Demand of Steel Beam-Columns under Fire. Journal of Structural Engineering, 137(9), 967-976. doi:10.1061/(asce)st.1943-541x.0000443Davidson, M. T., Harik, I. E., & Davis, D. B. (2013). Fire Impact and Passive Fire Protection of Infrastructure: State of the Art. Journal of Performance of Constructed Facilities, 27(2), 135-143. doi:10.1061/(asce)cf.1943-5509.0000295Allam, A., Nassif, A., & Nadjai, A. (2019). Behaviour of restrained steel beam at elevated temperature – parametric studies. Journal of Structural Fire Engineering, 10(3), 324-339. doi:10.1108/jsfe-11-2018-0036Santiago A, Haremza C, Simões da Silva L, Rodrigues JP. Numerical behaviour of steel columns subject to localized fire loading. In: Topping BH V., Costa Neves LF, Barros RC, editors. Proc. Twelfth Int. Conf. Civil, Struct. Environ. Eng. Comput., Stirlingshire, Scotland: Civil-Comp Press; 2009.Burges I, Alexandrou M. Composite beams. In: Ed. Wald F, Burgess I, Kwasniewski L, Horová K, Caldová E, editors. Benchmark Stud. Verif. Numer. Model. fire Eng. 1st ed., Prague: CTU Publishing House; 2014.Burges I, Alexandrou M. Steel beams. In: Ed. Wald F, Burgess I, Kwasniewski L, Horová K, Caldová E, editors. Benchmark Stud. Verif. Numer. Model. fire Eng. 1st ed., Prague: CTU Publishing House; 2014.Burgess I, Plank R, Shephered P. Vulcan 2019.Santiago A, Haremza C, Lopes F, Franssen JM. Numerical behaviour of steel columns under localized fire loading. In: Ed. Wald F, Burgess I, Kwasniewski L, Horová K, Caldová E, editors. Benchmark Stud. Exp. Valid. Numer. Model. fire Eng. 1st ed., Prague: CTU Publishing House; 2014.Franssen, J. M., Cooke, G. M. E., & Latham, D. J. (1995). Numerical simulation of a full scale fire test on a loaded steel framework. Journal of Constructional Steel Research, 35(3), 377-408. doi:10.1016/0143-974x(95)00010-sSrivastava, G., & Ravi Prakash, P. (2017). An integrated framework for nonlinear analysis of plane frames exposed to fire using the direct stiffness method. Computers & Structures, 190, 173-185. doi:10.1016/j.compstruc.2017.05.013EN 1993-1-2. Eurocode 3: Design of steel structures - Part 1-2: General rules - Structural fire design. Brussels: European Committee for Standardization; 2005.EN 1992-1-2. Eurocode 2: Design of concrete structures - Part 1-2: General rules - Structural fire design. Brussels: European Committee for Standardization; 2004.Purkiss JA, Li LY. Fire safety engineering design of structures. 3rd Editio. Boca Raton: CRC Press; 2013. https://doi.org/10.1201/b16059.Ansys. ANSYS Engineering Analysis System. User manual. Canonsburg, Pensilvania: Houston, Pa. : Swanson Analysis Systems, 2019; 2019.Oñate E. Structural Analysis with the Finite Element Method Linear Statics: Volume 2. Beams, Plates and Shells. 1st ed. Barcelona: Springer; 2013.Magisano, D., Liguori, F., Leonetti, L., de Gregorio, D., Zuccaro, G., & Garcea, G. (2019). A quasi-static nonlinear analysis for assessing the fire resistance of reinforced concrete 3D frames exploiting time-dependent yield surfaces. Computers & Structures, 212, 327-342. doi:10.1016/j.compstruc.2018.11.005Kiakojouri, F., De Biagi, V., Chiaia, B., & Sheidaii, M. R. (2020). Progressive collapse of framed building structures: Current knowledge and future prospects. Engineering Structures, 206, 110061. doi:10.1016/j.engstruct.2019.11006

New modeling strategies for analyzing lateral-torsional buckling in class-4 steel structural members at elevated temperatures using beam-type elements

[EN] Fire is one of the main hazards that can affect steel buildings and bridges and was responsible, e.g., for the collapse of the Plasco building in Tehran, Iran, and the I-65 bridge in Birmingham, Alabama, USA. This vulnerability has motivated the development of advanced computational models to predict the response of steel structures to fire accurately. The mechanical response of slender steel members to fire is especially important because they fail prematurely by buckling at load values below their elastic strength. However, the structural analysis of these members typically requires advanced and complex FE models with shell elements, including initial geometric and material imperfections. These shell models are computationally expensive, complicating the carrying out of parametric and probabilistic studies. Therefore, there is a need to develop simple, accurate, and low-cost computational models as reliable as shell-type models. To overcome this knowledge gap, this paper presents two new modeling strategies that simulate the mechanical response of class-4 steel members subjected to lateral-torsional buckling in fire using Timoshenko beam-type finite elements, which significantly simplify the structural modeling. These strategies are called Fiber Beam Model (FBM) and Cruciform Frame Model (CFM) and include initial geometric and material imperfections and thermal strains. In the FBM, the steel member is represented by a single fiber of I-section beam elements, whereas in the CFM, a cruciform arrangement of rectangular beam finite element fibers idealizes it, making the CFM more complex to build than FBM. Both strategies were satisfactorily validated with experimental and numerical results of Test-1 and Test-3 carried out in the ¿Fire design of steel members with welded or hot-rolled class-4 cross-section¿ (FIDESC4) research project on a slender beam of class-4 section. Although both FBM and CFM correctly captured the LTB resistance of the tested beam, CFM can, in addition, adequately reproduce the local buckling failure and significantly reduced the computational time. That means complex fire engineering problems such as probabilistic and optimization analyses of thin-walled beams can be addressed more easily and accurately, representing an important step towards applying performance-based approaches in slender steel structures under fire.Thanks are due to the Fundacion Carolina for the support given to this research through a Ph.D. scholarship.Pallares-Muñoz, MR.; Paya-Zaforteza, I.; Hospitaler Pérez, A. (2021). New modeling strategies for analyzing lateral-torsional buckling in class-4 steel structural members at elevated temperatures using beam-type elements. Structures. 34:3508-3532. https://doi.org/10.1016/j.istruc.2021.09.087S350835323

Impacto del consejo médico para dejar de fumar durante la gestación

ObjetivoEl consumo de tabaco entre las mujeres ha aumentado en España en los últimos años, especialmente entre los grupos en edad reproductiva. El objetivo del estudio es evaluar el impacto del consejo médico integrado en la atención prenatal sobre el consumo de tabaco durante el embarazo y en el posparto.DiseñoEstudio de intervención cuasiexperimental.EmplazamientoHospital del Mar de Barcelona.PacientesEl grupo control estaba constituido por 219 pacientes que acudieron para atención al parto al hospital del Mar en 1996, el grupo de intervención, por 169 pacientes atendidas durante el embarazo en el mismo hospital en 1997.IntervencionesLas pacientes del grupo control habían recibido atención habitual. Las gestantes del grupo de intervención recibieron de forma sistemática un consejo estructurado para dejar de fumar, reforzado por un folleto elaborado con esta finalidad.Mediciones y resultadosLos grupos de intervención y control no presentaban diferencias estadísticamente significativas en las variables sociodemográficas ni en el consumo de tabaco. En ambos grupos se determinó la evolución del hábito tabáquico durante el embarazo a lo largo de las visitas prenatales, y a los 6 meses posparto, a través de una entrevista telefónica. De las gestantes del grupo control, 44 (20,1%) habían dejado de fumar antes de la primera visita prenatal y 11 (5%) lo hicieron durante el embarazo. En el grupo de intervención 26 (17,7%) habían dejado de fumar espontáneamente y 16 (10,9%) dejaron de fumar durante el embarazo. De las que dejaron de fumar completamente durante el embarazo, se mantenían abstinentes a los 6 meses el 36,4% de las mujeres del grupo de control y el 64,3% en el grupo de intervención (p = 0,002).ConclusionesEl consejo para dejar de fumar en la visita prenatal produce un aumento discreto en la proporción de abandonos, y una disminución significativa de las recaídas en el posparto.ObjectiveWomen´s tobacco consumption has increased in Spain in recent years, especially among women of reproductive age. This study aims to evaluate the impact of medical counselling integrated into pre-natal care on tobacco consumption during pregnancy and the period after delivery.DesignQuasi-experimental intervention study.SettingHospital del Mar, Barcelona.Patients219 patients who attended the Hospital del Mar for delivery during 1996 (control group) and 169 patients seen during their pregnancies at the same hospital in 1997 (intervention group).InterventionsThe control group patients had received normal care. The pregnant women in the intervention group received systematic structured counselling on giving up smoking, backed up by a special brochure composed for this purpose.Measurements and resultsThe intervention and control groups showed no statistically significant differences either in their social or demographic variables or in their tobacco consumption. In both groups the evolution of their smoking during pregnancy was determined during their pre-natal visits and six months after delivery through a telephone interview. 44 of the women in the control group (20.1%) gave up smoking before their first pre-natal visit, and 11 (5%) gave up during pregnancy. In the intervention group 26 (17.7%) had given up spontaneously and 16 (10.9%) gave up during pregnancy. Of those who gave up completely during pregnancy, 36.4% of women in the control group and 64.3% in the intervention group remained abstinent at six months (P=.002).ConclusionsCounselling at pre-natal checkups to give up smoking lightly increases the number of women who give up and reduces significantly the number of post-delivery backsliders

DNA methylation at the Igf2/H19 imprinting control region is associated with cerebellum mass in outbred mice

Background: Insulin-like growth factor 2 (Igf2) is a paternally expressed imprinted gene regulating fetal growth, playing an integral role in the development of many tissues including the brain. The parent-of-origin specific expression of Igf2 is largely controlled by allele-specific DNA methylation at CTCF-binding sites in the imprinting control region (ICR), located immediately upstream of the neighboring H19 gene. Previously we reported evidence of a negative correlation between DNA methylation in this region and cerebellum weight in humans. Results: We quantified cerebellar DNA methylation across all four CTCF binding sites spanning the murine Igf2/H19 ICR in an outbred population of Heterogeneous Stock (HS) mice (n = 48). We observe that DNA methylation at the second and third CTCF binding sites in the Igf2/H19 ICR shows a negative relationship with cerebellar mass, reflecting the association observed in human post-mortem cerebellum tissue. Conclusions: Given the important role of the cerebellum in motor control and cognition, and the link between structural cerebellar abnormalities and neuropsychiatric phenotypes, the identification of epigenetic factors associated with cerebellum growth and development may provide important insights about the etiology of psychiatric disorders