The Persistence of Inflation in OECD Countries: A Fractionally Integrated Approach

The statistical properties of inflation and, in particular, its degree of persistence and stability over time is a subject of intense debate, and no consensus has been achieved yet. The goal of this paper is to analyze this controversy using a general approach, with the aim of providing a plausible explanation for the existing contradictory results. We consider the inflation rates of twenty-one OECD countries which are modeled as fractionally integrated (FI) processes. First, we show analytically that FI can appear in inflation rates after aggregating individual prices from firms that face different costs of adjusting their prices. Then, we provide robust empirical evidence supporting the FI hypothesis using both classical and Bayesian techniques. Next, we estimate impulse response functions and other scalar measures of persistence, achieving an accurate picture of this property and its variation across countries. It is shown that the application of some popular tools for measuring persistence, such as the sum of the AR coefficients, could lead to erroneous conclusions if fractional integration is present. Finally, we explore the existence of changes in inflation inertia using a novel approach. We conclude that the persistence of inflation is very high (although nonpermanent) in most postindustrial countries and that it has remained basically unchanged over the last four decades.

Analyzing aggregate real exchange rate persistence through the lens of sectoral data.

In this paper we analyze the persistence of aggregate real exchange rates (RERs) for a group of EU-15 countries by using sectoral data. The tight relation between aggregate and sectoral persistence recently investigated by Mayoral (2008) allows us to decompose aggregate RER persistence into the persistence of its different subcomponents. We show that the distribution of sectoral persistence is highly heterogeneous and very skewed to the right, and that a limited number of sectors are responsible for the high levels of persistence observed at the aggregate level. We use quantile regression to investigate whether the traditional theories proposed to account for the slow reversion to parity (lack of arbitrage due to nontradibilities or imperfect competition and price stickiness) are able to explain the behavior of the upper quantiles of sectoral persistence. We conclude that pricing to market in the intermediate goods sector together with price stickiness have more explanatory power than variables related to the tradability of the goods or their inputs.PPP puzzle, real exchange rates, persistence, heterogeneous dynamics, aggregation bias, nontradability, imperfect competition, pricing-to-market.

Increasing online shop revenues with web scraping: a case study for the wine sector

Purpose – Wine has been produced for thousands of years and nowadays we have seen a spread in the wine culture. E-commerce sales of wine have increased considerably and online customer’s satisfaction is influenced by quality and price. This paper presents a case study of the company “QuieroVinos, S.L.”, an online wine shop founded in 2015 that sells Spanish wines in two main marketplaces. Design/methodology/approach – With the final target of increasing the company profits it has been designed and developed an application to track the prices of competitors for a set of products. This information will be used to set the product prices in order to offer the products both competitively and profitably in each Marketplace. This application must check, by tacking into account information such as the product cost or the minimum product margin, if it is possible to decrease the price in order to reach the top cheapest position and as a consequence, increase the sales. Findings – The application improved in a notorious way the company’s results in terms of sales and shipping costs. It must be said that without the use of the presented application, performing the price comparison process within each one of the marketplaces would have taken a long time. Moreover, as prices change very frequently, the obtained information has a very limited time value, and the competitors prices should be analyzed daily in order to take accurate decisions regarding the company’s price policy. Originality/value – Although the application has been designed for the wine sector and the two named marketplace, it could be exported to other sectors. For that, it should be implemented new modules to collect information regarding the competitor’s price of the products selling on each corresponding marketplaceThis work was supported by the Ministerio de Economía y Competitividad under contract TIN2017- 84553-C2-2-R. Also, the authors are members of the research group 2017-SGR363, funded by the Generalitat de Catalunya

Bayesian design and analysis of replications in scientific experimentation

En la práctica estadística es frecuente la replicación de experiencias estadísticas, justificada por muy diversos intereses: ratificar conclusiones, estudiar la variación en las respuestas cuando se experimenta sobre una población distinta, validar un modelo, detectar sesgos, etc. Al disponer, antes de replicar, de los resultados de cierto estudio previo, es razonable pensar en buscar un buen diseño para la réplica utilizando la información que dicho primer estudio proporciona. Un diseño óptimo de la réplica consistirá en decidir, asumido un modelo, sobre el menor tamaño muestral que otorga al investigador suficientes garantías de concluir con éxito en su inferencia. Una modelización jerárquica bayesiana permite precisar fácilmente las relaciones entre datos y poblaciones (original y replicada) y derivar conclusiones sobre los resultados más probables (en función del tamaño de la réplica) a través de las distribuciones a posteriori y predictivas que se obtengan

The education under the Spanish Moroccan Protectorate throughout three magazines of the Spanish Africanist League (1913-1931)

Colonialism and postcolonialism are important stages in the history of many European countries such as Great Britain, France, Holland, Portugal or Spain. However, rarely are the colonies taken into account in the history of education of these countries. In the case of Spain, it has scarcely been explored throughout most of the Century XX. The establishment of the Protectorate in the north of Morocco in 1912 meant the need to put in place measures to control the territory and the population. From early on, education was considered as an colonisation agent and several models of education appeared: colonial school, traditional school and nationalist school. Each one had a different target audience and different aims. The Digital Periodicals Library of the National Library offers three journals on the Spanish Protectorate in Morocco. They present a continuity between 1913 and 1931. The first is África Española. Revista de Colonización (1913-1917). This one was followed by Boletín de la Liga Africanista Española (1917-1923) and later by Revista hispano africana (1923-1931). Our main goal is to analyze the contents of these journals of the Spanish Africanist League on education, grouping them around descriptors such as educational levels, teachers and debates on education, as well as the impact of the Spanish culture on the Protectorate throughout the educational institutions.Proyecto EDU2014-53679-P y Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Tomografía por Emisión de Positrones cuantificada en la evaluación prequirúrgica de la epilepsia

[spa] La epilepsia es una enfermedad con una elevada prevalencia e impacto sociosanitario. Aproximadamente un tercio de los pacientes son resistentes al tratamiento farmacológico y en estos casos debe considerarse la cirugía como la única opción potencialmente curativa. El éxito de la cirugía de la epilepsia está directamente relacionado con la precisa localización y resección del córtex epileptógeno, por lo que es crucial realizar una exhaustiva valoración prequirúrgica considerando varias modalidades diagnósticas. Los estudios de neuroimagen funcional como la PET, analizados visual y objetivamente mediante programas informáticos específicos, pueden desempeñar un papel decisivo en este contexto. Este trabajo de investigación se ha basado en la publicación dos estudios. En el primer estudio se incluyeron retrospectivamente 55 pacientes con epilepsia resistente al tratamiento farmacológico a los que se les realizó una PET con 18F-FDG que se interpretó como normal o con hallazgos muy sutiles o dudosos al análisis visual. De entre los pacientes incluidos, 20 habían sido operados con buenos resultados postquirúrgicos (Engel I-II). Se analizaron todos los estudios PET con SPM. Se usaron como dinteles de segmentación un valor de p corregido de p<0,05 con un tamaño mínimo de cluster k=0 (combinación 1 o C1), y tres valores de p no corregidos que eran gradualmente mayores con tamaños mínimos de cluster que también eran progresivamente de mayor tamaño. Estas tres combinaciones fueron p<0,0001 con k=20 (C2), p<0,001 con k=100 (C3) y p=0,005 con k=200 (C4). SPM evidenció áreas hipometabólicas en los estudios PET dudosos o negativos al análisis visual incluídos con los cuatro dinteles. La localización correcta de la ZE aumentó de forma progresiva desde el dintel con valor de p más restrictivo hasta el más liberal (de C1 a C4). En el grupo de pacientes operados, la proporción máxima de estudios correctamente localizadores se obtuvo con el dintel C4, que fue del 55% (11/20), una proporción ligeramente inferior al 65% (13/20) obtenido con la RM. Sin embargo, no se encontraron diferencias estadísticamente significativas entre estas dos proporciones. C3 fue el segundo dintel con la máxima proporción de estudios correctamente localizadores, acertando en la localización de la ZE en el 40% (8/20) de los pacientes operados. En el análisis global de los 55 pacientes, C4 también obtuvo la máxima proporción con un 40% (22/55) de estudios correctamente localizadores, y C3 obtuvo la segunda máxima proporción con un 29.1% (16/55). El aumento progresivo de estudios positivos de C1 a C4 no conllevó un aumento relevante en la proporción de estudios falsamente localizadores. Hubo tres pacientes operados en los que ni la RM ni la PET con SPM detectaron algun área que potencialmente pudiese ser la ZE. La concordancia entre la ZE y el dintel C1 fue justa y moderada con C2, C3 y C4. Cuando se analizó por separado a los pacientes operados las concordancias aumentaron, siendo substancial para C2 (к = 0,696; 95% IC 0,303–1,000) y C4 (к = 0,607; 95% IC 0,258–0,957), valores similares a los obtenidos con la RM (к = 0,783; 95% IC 0,509–1,000). Cuatro pacientes que tuvieron estudios de RM negativos o falsamente localizadores de la ZE tuvieron estudios PET correctamente localizadores tras el análisis con SPM. En el segundo estudio se incluyeron 30 pacientes con epilepsia refractaria al tratamiento farmacológico a los que se realizó una PET con 18F-FDG y que tuvieron unos resultados posoperatorios óptimos. Los estudios PET se evaluaron visualmente, con SPM y con PET-analysis. Para el análisis con SPM, se usaron los dinteles p corregida 50 y p no corregida 100. Como PET-analysis procesa rápidamente varias combinaciones de dinteles de significación, se usaron múltiples dinteles basados en combinaciones de diferentes desviaciones estándar y tamaños de cluster. PET-analysis obtuvo un 66,7% (20/30) de estudios correctamente localizadores de la ZE, comparable con el 70,0% (21/30) obtenido mediante el análisis visual y significativamente superior (p100, que obtuvo 36,7% (11/30). Sólo un estudio fue positivo, aunque no localizador, con el dintel de SPM p50. En cuanto a la RM, un 16/30 (53,3%) de los estudios fueron correctamente localizadores. La concordancia de la ZE posquirúrgica fue sustancial con PET-analysis (к=0,643, IC95% 0,439-0,847) y la interpretación visual (к=0,622, IC95% 0,367-0,877), pero fue débil con SPM (к=0,242, IC95% 0,028-0,455) y moderada con la RM (к=0,520, IC95% 0,268-0,772). En comparación con SPM, PET-analysis podría ser superior para la localización de la ZE con su procesado rápido y sencillo de diferentes combinaciones de dinteles de significación. Los resultados de este estudio validan el uso clínico de PET-analysis como una herramienta robusta complementaria al análisis visual en la localización de la ZE.[eng] FIRST ARTICLE SUMMARY Seizure onset zone localization by Statistical Parametric Mapping in visually normal 18F-FDG PET studies Introduction and objective: Neuroimaging is crucial in the presurgical evaluation of patients with medically refractory epilepsy. To improve the moderate sensitivity of [18F]fluorodeoxyglucose (18F-FDG) positron emission tomograpghy (PET) our aim was to evaluate the usefulness of Statistical Parametric Mapping (SPM) to localize the seizure onset zone (SOZ) in PET studies deemed normal by visual assessment. Methods: Fifty-five patients with medically refractory epilepsy whose 18F-FDG PET was visually evaluated as normal were retrospectively included. Twenty of these patients were surgically-intervened. PET images were analysed by SPM8 using a corrected p value of p0, k>20, k>100 and k>200, respectively. The SPM-identified potential seizure zone (SZ) was compared to the SOZ, which was determined by consensus during patient management meetings in the Epilepsy Unit, taking into account presurgical tests. Studies in which the SPM-identified potential SZ was concordant with the SOZ were considered “correctly localizing”. Results: The SPM threshold combination with the least restrictive p-value and greatest minimum cluster size achieved the highest rate of correctly localizing studies. When p200 was used, 40% (22/55) of studies were correctly localizing, and the concordance obtained in the surgically-intervened subgroup was substantial (к=0.607, CI95% 0.258,0.957), which was comparable to the concordance obtained by MRI (к=0.783, CI95% 0.509,1.000). Conclusion: SPM offers improved SOZ localization in 18F-FDG PET studies that are negative on visual assessment. For this purpose, statistical parametric maps could be thresholded with liberal p-values and restrictive cluster sizes. SECOND ARTICLE SUMMARY Epileptogenic Zone Localization with 18FDG PET Using a New Dynamic Parametric Analysis Introduction and objective: [18F]fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is part of the regular preoperative work-up in medically refractory epilepsy. As a complement to visual evaluation of PET, statistical parametric maps can help in the detection of the epileptogenic zone (EZ). However, software packages currently available are time-consuming and little intuitive for physicians. We develop a user-friendly software (referred as PET-analysis) for EZ localization in PET studies that allows dynamic real-time statistical parametric analysis. To evaluate its performance, the outcome of PET-analysis was compared with the results obtained by visual assessment and Statistical Parametric Mapping (SPM). Methods: Thirty patients with medically refractory epilepsy who underwent presurgical 18F-FDG PET with good postoperative outcomes were included. The 18F-FDG PET studies were evaluated by visual assessment, with SPM8 and PET-analysis. In SPM, parametric T-maps were thresholded at corrected p<0.05 and cluster size k=50 and at uncorrected p<0.001 and k=100 (the most used parameters in the literature). Since PET-analysis rapidly processes different threshold combinations, T-maps were thresholded with multiple p-value and different clusters sizes. The presurgical EZ identified by visual assessment, SPM and PET-analysis was compared to the confirmed EZ according to postsurgical follow-up. Results: PET-analysis obtained 66.7% (20/30) of correctly localizing studies, comparable to the 70.0% (21/30) achieved by visual assessment and significantly higher (p<0.05) than that obtained with the SPM threshold p<0.001/k=100, of 36.7% (11/30). Only one study was positive, albeit non-localizing, with the SPM threshold corrected p<0.05/k=50. Concordance was substantial for PET-analysis (к=0.643) and visual interpretation (к=0.622), being fair for SPM (к=0.242). Conclusion: Compared to SPM with the fixed standard parameters, PET-analysis may be superior in EZ localization with its easy and rapid processing of different threshold combinations. The results of this initial proof-of-concept study validate the clinical use of PET-analysis as a robust objective complementary tool to visual assessment for EZ localization

Opportunities from Metal Organic Frameworks to Develop Porous Carbons Catalysts Involved in Fine Chemical Synthesis

Funding Information: This work has been supported by Project ref. PID2021-126579OB-C32 from MCIN/AEI/10.13039/501100011033 and Project ref. UFV2023-38 from Universidad Francisco de Vitoria de Madrid. This work also received financial support from PT national funds (FCT/MCTES, Fundação para a Ciência e Tecnologia and Ministério da Ciência, Tecnologia e Ensino Superior) through the projects UIDB/50006/2020 and UIDP/50006/2020. Maria Bernardo thanks FCT (Fundação para a Ciência e Tecnologia) for funding through program DL 57/2016—Norma transitória. Publisher Copyright: © 2023 by the authors.In the last decade, MOFs have been proposed as precursors of functional porous carbons with enhanced catalytic performances by comparison with other traditional carbonaceous catalysts. This area is rapidly growing mainly because of the great structural diversity of MOFs offering almost infinite possibilities. MOFs can be considered as ideal platforms to prepare porous carbons with highly dispersed metallic species or even single-metal atoms under strictly controlled thermal conditions. This review briefly summarizes synthetic strategies to prepare MOFs and MOF-derived porous carbons. The main focus relies on the application of the MOF-derived porous carbons to fine chemical synthesis. Among the most explored reactions, the oxidation and reduction reactions are highlighted, although some examples of coupling and multicomponent reactions are also presented. However, the application of this type of catalyst in the green synthesis of biologically active heterocyclic compounds through cascade reactions is still a challenge.publishersversionpublishe

The Persistence of Inflation in OECD Countries: A Fractionally Integrated Approach

The statistical properties of inflation and, in particular, its degree of persistence and stability over time is a subject of intense debate, and no consensus has been achieved yet. The goal of this paper is to analyze this controversy using a general approach, with the aim of providing a plausible explanation for the existing contradictory results. We consider the inflation rates of twenty-one OECD countries which are modeled as fractionally integrated (FI) processes. First, we show analytically that FI can appear in inflation rates after aggregating individual prices from firms that face different costs of adjusting their prices. Then, we provide robust empirical evidence supporting the FI hypothesis using both classical and Bayesian techniques. Next, we estimate impulse response functions and other scalar measures of persistence, achieving an accurate picture of this property and its variation across countries. It is shown that the application of some popular tools for measuring persistence, such as the sum of the AR coefficients, could lead to erroneous conclusions if fractional integration is present. Finally, we explore the existence of changes in inflation inertia using a novel approach. We conclude that the persistence of inflation is very high (although nonpermanent) in most postindustrial countries and that it has remained basically unchanged over the last four decades

Acompanyament al professorat novell: avaluació d'un programa per a la construcció del coneixement professional

L’objectiu principal d’aquesta recerca és avaluar l’eficàcia d’un programa dissenyat per pal•liar el xoc de realitat i fomentar la reflexió sobre la pràctica al llarg del procés d’inducció professional del professorat novell d’Educació Secundària i Cicles Formatius en el seu context, tot afavorint-ne, així, la construcció de coneixement professional. Aquesta avaluació pren forma en l’anàlisi de diverses dimensions. La primera consisteix a estudiar l’impacte del programa en els problemes dels novells per constatar si es redueixen, així com copsar els problemes dels tutors per poder promoure (en futures recerques) ajudes en aquesta direcció. La segona dimensió se centra a identificar les ajudes que faciliten la construcció del coneixement professional, sobretot les que s’articulen directament a través del tutor i, especialment, l’efecte del feedback envers el professor novell. La tercera dimensió analitza la interacció entre iguals en una comunitat d’aprenentatge per veure si es produeix un canvi en les creences dels participants i, sobretot, si la reflexió sobre la pròpia acció i la dels altres promou la construcció del coneixement professional. I la quarta dimensió vol evidenciar quins elements del programa són considerats més satisfactoris pels participants, i també quins altres aspectes es podrien millorar a l’hora de redissenyar-lo. L’estudi s’ha dut a terme a través de la implementació d’un programa d’inducció professional durant el curs 2006-2007 i amb 5 parelles (novell-tutor). S’han analitzat cinc àrees temàtiques (concepcions sobre ensenyament i aprenentatge, motivació, classroom management, conducta i avaluació dels alumnes) mitjançant de tres accions: a) lectura especialitzada i fòrums virtuals, b) observació i feedback del tutor cap al professor novell i c) grups de reflexió sobre la pràctica docent amb anàlisi de les bones pràctiques. Les dades recollides corresponen als enregistraments del discurs en cada àrea i acció, juntament amb les dades obtingudes d'una entrevista semi-estructurada (inicial-final). Per assolir els objectius s’ha fet un estudi interpretatiu i longitudinal, de modalitat participant i basat en una metodologia de recerca-acció amb component avaluador. S’ha optat per un enfocament d’anàlisi qualitativa (amb el programa Atlas.ti), segons la Grounded Theory, mitjançant l’anàlisi del contingut i de les estratègies discursives i els patrons d’interacció seguint la proposta de Hogan, Nastasi i Pressley (2000). Els resultats mostren coincidències amb la literatura especialitzada quant als problemes dels novells, especialment els d'atenció a la diversitat, socialització, disciplina dels alumnes i falta de coneixements, que es redueixen al llarg del programa. Al seu torn, els tutors mostren alguns problemes de comunicació amb els novells que es mantenen al llarg del programa. Tot i que les ajudes proporcionades pels tutors prenen diferents formes, la transmissió de feedback després de l’observació de la pràctica del novell a l’aula és la més efectiva des de la perspectiva de tots dos. Pel que fa a la pràctica professional, els grups de reflexió mostren el següent: que els tòpics més recurrents corresponen a les àrees problemàtiques indicades pels novells; que els tutors usen estratègies metacognitives i els novells, conceptuals; i que es promou la reelaboració i enriquiment de les creences inicials en totes les àrees treballades. A més, la implementació del programa ha permès conèixer propostes de canvi i comprovar també que el format dels grups de reflexió és un model vàlid d’assessorament col•laboratiu.El objetivo principal de esta investigación es evaluar la eficacia de un programa diseñado para paliar el choque de realidad y fomentar la reflexión sobre la práctica a lo largo del proceso de inducción profesional del profesorado novel de Educación Secundaria y Ciclos Formativos en su contexto, favoreciendo así, la construcción de conocimiento profesional. Esta evaluación se articula a través de varias dimensiones. La primera consiste en estudiar el impacto del programa en los problemas de los noveles para constatar si se reducen, así como recoger los problemas de los tutores para poder promover (en futuras investigaciones) ayudas en esta dirección. La segunda dimensión se centra en identificar las ayudas que facilitan la construcción del conocimiento profesional, sobre todo las que se articulan directamente a través del tutor y, especialmente, el efecto del feedback hacia el profesor novel. La tercera dimensión analiza la interacción entre iguales en una comunidad de aprendizaje para ver si se produce un cambio en las creencias de los participantes y, sobre todo, si la reflexión sobre la propia acción y la de los otros promueven la construcción del conocimiento profesional. Y la cuarta dimensión quiere evidenciar qué elementos del programa son considerados más satisfactorios por los participantes, y también qué otros aspectos se podrían mejorar a la hora de rediseñarlo. El estudio se ha llevado a cabo a través de la implementación de un programa de inducción profesional durante el curso 2006-2007 y con 5 parejas (novel-tutor). Se han analizado cinco áreas temáticas (concepciones sobre enseñanza y aprendizaje, motivación, classroom management, conducta y evaluación de los alumnos) a través de tres acciones: a) lectura especializada y foros virtuales, b) observación y feedback del tutor al profesor novel y c) grupos de reflexión sobre la práctica docente con el análisis de buenas prácticas. Los datos recogidos corresponden a las grabaciones del discurso en cada área y acción, junto con los datos obtenidos de una entrevista semi-estructurada (inicial-final). Para lograr los objetivos se ha llevado a cabo un estudio interpretativo y longitudinal, de modalidad participante y basado en una metodología de investigación-acción con componente evaluador, y de enfoque de análisis cualitativo (con el programa Atlas.ti), según la Grounded Theory (analizando el contenido y las estrategias discursivas y los patrones de interacción, Hogan, Nastasi y Pressley (2000). Los resultados muestran coincidencias con la literatura especializada en cuanto a los problemas de los noveles, especialmente los de atención a la diversidad, socialización, disciplina de los alumnos y falta de conocimientos, que se reducen a lo largo del programa. A su vez, los tutores muestran algunos problemas de comunicación con los noveles que se mantienen a lo largo del programa. Aun cuando las ayudas proporcionadas por los tutores presentan diferentes formas, la transmisión de feedback tras la observación de la práctica del novel en el aula es la más efectiva desde la perspectiva de los dos. Con respecto a la práctica profesional, los grupos de reflexión muestran lo siguiente: que los tópicos más recurrentes corresponden a las áreas problemáticas indicadas por los noveles; que los tutores utilizan estrategias metacognitivas y los noveles, conceptuales; y que se promueve la reelaboración y el enriquecimiento de las creencias iniciales en todas las áreas trabajadas. Además, la implementación del programa ha permitido conocer propuestas de cambio y comprobar también que el formato de los grupos de reflexión es un modelo válido de asesoramiento colaborativo.The main goal of this research is to assess the effectiveness of a program designed to reduce the reality shock and to promote reflection on practice teaching during the beginning secondary school teacher’s induction phase, thus promoting the construction of professional knowledge. This assessment covers a number of dimensions. The first involves studying the program's impact on the problems of the beginning teachers to see if they have been reduced and also recording the problems of mentors so as to find solutions (in future research). The second dimension focuses on identifying elements that promote the construction of professional knowledge, especially those that are directly related to the effect of feedback to the beginning teacher. The third dimension examines the interaction between peers in a learning community to see if there is a change in the beliefs of participants and, especially, in the construction of professional knowledge. And the fourth dimension is related to showing what elements of the program are considered most successful by participants, and also what else could be improved at the time of redesign. The study was conducted during the implementation of a professional induction program involving five beginning teacher-mentor pairs during the 2006-2007 school year. We worked five areas (teaching and learning conceptions, motivation, classroom management, behavior and students assessment) through three activities: a) participation in a forum on-line, b) observation and feedback to the beginning teacher from the mentor and c) focus groups about teaching practices. The data collected comes from the recordings of the speech in each area and action and also, from a semi-structured interview (beginning-end). To achieve the goals we have conducted a longitudinal, participant and interpreting study based on a research-action methodology with an assessment component. We took a qualitative analysis approach (using the Atlas.ti program), in accordance with the Grounded Theory, analyzing the content and the discourse strategies and interaction patterns following the model proposed by Hogan, Nastasi & Pressley (2000). The results show similarities with the literature regarding beginning teachers’ problems, especially those regarding individual differences, socialization, disciplining of students and lack of knowledge, which decrease over the course of the program. In turn, mentors showed some communication problems with the beginning teachers that continued throughout the program. Nevertheless, feedback after watching the beginning teachers’ practice sessions in the classroom was considered the most effective activity by both beginning teachers and mentors. Regarding professional practice, focus groups showed the following: the most frequently raised issues were related to the problem areas identified by the beginning teachers; mentors used metacognitive strategies whereas beginning teachers used conceptual strategies; and all activities promote the reformulation and enrichment of the initial beliefs in all areas worked. Furthermore, the implementation of the program has allowed us to exchange proposals and also verify that the structure of focus groups is a valid model for collaborative coaching

The Persistence of Inflation in OECD Countries: A Fractionally Integrated Approach

The statistical properties of inflation and, in particular, its degree of persistence and stability over time is a subject of intense debate, and no consensus has been achieved yet. The goal of this paper is to analyze this controversy using a general approach, with the aim of providing a plausible explanation for the existing contradictory results. We consider the inflation rates of twenty-one OECD countries which are modeled as fractionally integrated (FI) processes. First, we show analytically that FI can appear in inflation rates after aggregating individual prices from firms that face different costs of adjusting their prices. Then, we provide robust empirical evidence supporting the FI hypothesis using both classical and Bayesian techniques. Next, we estimate impulse response functions and other scalar measures of persistence, achieving an accurate picture of this property and its variation across countries. It is shown that the application of some popular tools for measuring persistence, such as the sum of the AR coefficients, could lead to erroneous conclusions if fractional integration is present. Finally, we explore the existence of changes in inflation inertia using a novel approach. We conclude that the persistence of inflation is very high (although nonpermanent) in most postindustrial countries and that it has remained basically unchanged over the last four decades