Optimal Monetary Policy under Adaptive Learning

We consider optimal policy when private sector expectations are formed through adaptive learning. Earlier research has found that adaptive learning is consistent with empirical evidence on private sector expectations. In this paper, we consider the (admittedly) extreme case of sophisticated central banking, whereby the central bank has full knowledge about the structure of the economy. Our results confirm that the management of inflation expectations is crucial for the conduct of monetary policy. n particular, when the private sector perceives that inflation persistence is high, optimal policy responds strongly to lagged inflation and inflation shocks thereby stabilizing inflation and anchoring inflation expectations. For our parametrization it does so at no cost for output gap stabilityOptimal Policy, Adaptive Learning, Rational Expectations, Policy Rules

Adaptive learning, persistence, and optimal monetary policy

We show that, when private sector expectations are determined in line with adaptive learning, optimal policy responds persistently to cost-push shocks. The optimal response is stronger and more persistent, the higher is the initial level of perceived inflation persistence by the private sector. Such a sophisticated policy reduces inflation persistence and inflation volatility at little cost in terms of output gap volatility. Persistent responses to cost-push shocks and stability of inflation expectations resemble optimal policy under commitment and rational expectations. Nevertheless, it is clear that the mechanism at play is very different. In the case of commitment it relies on expectations of future policy actions affecting inflation expectations; in the case of sophisticated central banking it relies on the reduction in the estimated inflation persistence parameter based on inflation data generated by shocks and policy responses. JEL Classification: E52Adaptive learning, optimal policy, policy rules, Rational Expectations

Is time ripe for price level path stability?

In the paper, we provide a critical and selective survey of arguments relevant for the assessment of the case for price level path stability (PLPS). Using a standard hybrid new Keynesian model we argue that price level stability provides a natural framework for monetary policy under commitment. There are two main arguments in favour of a PLPS regime. First, it helps overall macroeconomic stability by making expectations operate like automatic stabilizers. Second, under a price level path stability regime, changes in the price level operate like an intertemporal adjustment mechanism, reducing the magnitude of required changes in nominal interest rates. Such a property is particularly relevant as a means to alleviate the importance of the zero bound on nominal interest rates. We also review and discuss the arguments against price level path stability. Finally, we also found, using the Smets and Wouters (2003) model which includes a wide variety of frictions and is estimated for the euro area, that the price level is stationary under optimal policy under commitment. The results obtain when the quasi-difference of inflation is used in the loss function, as in the hybrid new Keynesian model. Overall, the arguments in favour of or against price level path stability depend on the degree of dependence of private sector expectations on the characteristics of the monetary policy regime. JEL Classification: E52, D83Adaptive Learning, expectations, Price Level Stability

Is Time Ripe for Price Level Path Stability?

In the paper, we provide a critical and selective survey of arguments relevant for the assessment of the case for price level path stability (PLPS). Using a standard hybrid new Keynesian model we argue that price level stability provides a natural framework for monetary policy under commitment. There are two main arguments in favour of a PLPS regime. First, it helps overall macroeconomic stability by making expectations operate like automatic stabilizers. Second, under a price level path stability regime, changes in the price level operates like an intertemporal adjustment mechanism, reducing the magnitude of required changes in nominal interest rates. Such a property is particularly relevant as a means to alleviate the importance of the zero bound on nominal interest rates. We also review and discuss the arguments against price level path stability. Finally, we also found, using the Smets and Wouters (2003) model which includes a wide variety of frictions and is estimated for the euro area, that the price level is stationary under optimal policy under commitment. The results obtain when the quasi-difference of inflation is used in the loss function, as in the hybrid new Keynesian model. Overall, the arguments in favour of or against price level path stability depend on the degree of dependence of private sector expectations on the characteristics of the monetary policy regime.Key words: Price Level Stability, Expectations, Adaptive Learning

KOI-142, the King of Transit Variations, is a Pair of Planets near the 2:1 Resonance

The Transit Timing Variations (TTVs) can be used as a diagnostic of gravitational interactions between planets in a multi-planet system. Many Kepler Objects of Interest (KOIs) exhibit significant TTVs, but KOI-142.01 stands out among them with an unrivaled, 12-hour TTV amplitude. Here we report a thorough analysis of KOI-142.01's transits. We discover periodic Transit Duration Variations (TDVs) of KOI-142.01 that are nearly in phase with the observed TTVs. We show that KOI-142.01's TTVs and TDVs uniquely detect a non-transiting companion with a mass 0.7 that of Jupiter (KOI-142c). KOI-142.01's mass inferred from the transit variations is consistent with the measured transit depth, suggesting a Neptune class planet (KOI-142b). The orbital period ratio P_c/P_b=2.03 indicates that the two planets are just wide of the 2:1 resonance. The present dynamics of this system, characterized here in detail, can be used to test various formation theories that have been proposed to explain the near-resonant pairs of exoplanets

Electrodialytic recovery of tungsten and cobalt from an industrial residue – preliminary assessment

Critical raw materials (CRMs) have a significant importance for key sectors in the European economy. This importance will continue to grow due to the Green Deal, as the sustainable transition to carbon neutrality by 2050 is settled in modern technologies and renewable energies, which are closely linked to a need for many raw materials. Europe is very highly dependent on imports of most of the raw materials needed by European industries, with a set of CRMs presenting a high level of concentration in particular countries, some of them geopolitically unstable. For this reason, the supply chains security depends largely on efficient management of resources throughout the lifecycle and the commitment to recycling using secondary resources, such as industrial residues. Investing in CRMs' recycling processes and their sustainability is essential to maintain the supply chains. The present work is the first attempt to study the application of the electrodialytic (ED) process for recovery of two CRMs, tungsten (W) and cobalt (Co), from tungsten carbide (WC-Co) scrap powder resultant from end-of-life cutting tools. ED process consists of the application of a low-level electric current, in the presence of cation and/or anion exchange membranes, which promote the separation between compartments. In this specific work, acid desorption of W and Co from the matrix was carried out, followed by electromigration and electrodialysis. Eight experiments were carried out during 24h, using ED cells with three (3C) and two (2C) compartments to perform three assessments: the best electrolyte, the best solid:liquid ratio, and the best current intensity. The WC-Co matrix was placed in the central cell compartment in the 3C setup and directly in the anode in a 2C cell. The results show that the 2C cell setup with NaCl 0.02 M as catholyte and citric acid 0.4 M as anolyte, a solid:liquid ratio 1:25, and an initial current intensity of 200 mA presented the highest W (2194 mg; 99.6% of total W solubilized) and Co (558 mg; 81.3% of total Co solubilized) recovery. However, the current intensity was not completely optimized yet and needs further investigation. This dissertation will contribute to guide future experimental work to optimize the ED conditions for W and Co recovery.As matérias-primas críticas (CRMs) possuem uma importância significativa para setores-chave da economia europeia. Essa importância vai continuar a aumentar com o Pacto Ecológico Europeu, uma vez que a transição sustentável para a neutralidade carbónica em 2050 está assente em tecnologias modernas e energias renováveis, intimamente ligadas a uma grande necessidade de um vasto número de matérias-primas. A Europa depende largamente das importações da maioria das matérias-primas necessárias às suas indústrias, materiais esses altamente concentrados num conjunto de países específicos, alguns deles geopoliticamente instáveis. Por esse motivo, a segurança das cadeias de abastecimento depende em grande parte da gestão eficiente dos recursos ao longo do seu ciclo de vida e do compromisso com a reciclagem, recorrendo a fontes secundárias como resíduos industriais. Investir nestes processos, bem como a garantir a sua sustentabilidade, é fundamental para assegurar a manutenção das cadeias de abastecimento. O presente trabalho consiste na primeira tentativa de estudar a aplicação do processo eletrodialítico (ED) para recuperação de duas matérias-primas críticas, tungsténio (W) e cobalto (Co), a partir de um pó de carbeto de tungsténio (WC-Co) macerado, resultante de ferramentas de corte em fim-de-vida. O processo ED consiste na aplicação de uma corrente elétrica de baixa intensidade, na presença de membranas de troca catiónica e/ou aniónica, que promovem a separação entre compartimentos. Neste trabalho específico, foi realizada uma dessorção ácida de W e Co da matriz sólida, seguida de eletromigração e eletrodiálise. Cada uma de oito experiências foi realizada durante 24h, utilizando células ED com três (3C) e dois (2C) compartimentos com três objetivos: obter o melhor eletrólito, o melhor rácio sólido:líquido e a melhor intensidade de corrente. A matriz de WC-Co foi colocada no compartimento central da célula 3C e diretamente no ânodo na célula 2C. Os resultados mostram que a configuração da célula 2C com NaCl 0.02 M como catolito e ácido cítrico 0.4 M como anolito, um rácio sólido:líquido de 1:25 e uma intensidade de corrente inicial de 200 mA apresentou a maior recuperação de W (2194 mg; 99.6% do total de W solubilizado) e Co (558 mg; 81.3% do total de Co solubilizado). No entanto, a intensidade da corrente ainda não foi completamente otimizada, necessitando de mais investigação. Esta dissertação contribuirá para futuros trabalhos experimentais com vista a otimizar as condições do processo ED para a recuperação de W e Co

Understanding and improving oral corrective feedback in primary FL classrooms in Portugal

The main axis of this study is the analysis of oral corrective feedback (OCF) procedures in the context of teaching English in primary school in Portugal. It presents a deeper understanding of OCF strategies and establishes links between these and their potential effectiveness. The study encompassed the audio recording, transcription and analysis of ten 45 minutes lessons at a private school in Lisbon, an online survey to primary teachers of English in Portugal, an interview with my co-operating teacher, a questionnaire to the learners involved in the research and a learning journal. As the study was implemented, my approach to OCF changed considerably. Results show that OCF is an inevitable and highly complex process, that there is little evidence to corroborate that it is detrimental to learning and that it can and should be assumed as a powerful tool for enhanced English teaching/learning in the primary context.O eixo principal deste estudo é o da análise dos procedimentos de correção oral de erros (OCF) no contexto do ensino de Inglês na escola primária em Portugal. Apresenta um entendimento aprofundado das estratégias de OCF e estabelece ligações entre estas e a sua potencial eficácia. O estudo abrangeu a gravação áudio, transcrição e análise de 10 aulas de 45 minutos numa escola privada em Lisboa, um inquérito online a professores de Inglês na primária em Portugal, uma entrevista à professora cooperante, um questionário aos alunos envolvidos na pesquisa e um diário do professor. No decorrer da implementação, a minha abordagem à OCF alterou-se de forma significativa. Os resultados demonstram que a OCF é um processo inevitável e altamente complexo, que não existem dados suficientes para corroborar efeitos negativos na aprendizagem e que a OCF pode, e deve, ser assumida como uma ferramenta poderosa na melhoria do ensino/aprendizagem de Inglês no contexto da escola primária

A new manual wheelchair propulsion system with self-locking capability on ramps

A wheelchair user faces many difficulties in their everyday attempts to use ramps, especially those of some length. The present work describes the design and build of a propulsion system for manual wheelchairs for use in ascending or descending long ramps. The design is characterized by a self-locking mechanism that activates automatically to brake the chair when the user stops pushing. The system consists of a planetary transmission with a self-locking capacity coupled to a push rim with which the user moves the system. Different transmission ratios are proposed, adapted to the slope and to the user’s physical capacity (measured as the power the user can apply over ample time periods). The design is shown to be viable in terms of resistance, and approximate dimensions are established for the height and width of the propulsion system. Also, a prototype was built in order to test the self-locking system on ramps

Propriedades da córnea e glaucoma : revisão da literatura e meta-análise

SciELO - Scientific Electronic Library Online. ABO is licensed under a Creative Commons Attribution-NonComercial 4.0 Internacional.Purpose: Studies have suggested that corneal biomechanical properties influence intraocular pressure (IOP) measurements, namely central corneal thickness (CCT) and corneal hysteresis (CH). The present study aimed to investigate the associations of CH and CCT with glaucoma development. Methods: We performed a review of the literature and meta-analysis of observational studies (2006-2016) that included both adult glaucoma patients and controls and reported CCT and CH as outcomes. Nineteen studies were conside red eligible, and the mean difference (MD) between groups (patient and control) for both variables was used for statistical analyses. Results: A total of 1,213 glaucoma and 1,055 healthy eyes were studied. Quan titative analysis suggested that CH was significantly lower in the glaucoma group than in the control group (MD=-1.54 mmHg, 95% CI [-1.68, -1.41], P<0.0001). Additionally, CCT was significantly lower in the glaucoma group than in the control group (MD=-8.49 µm, 95% CI [-11.36, -5.62], P<0.001). Conclusion: Corneal properties appear to differ between glaucoma patients and healthy controls. Our results emphasize the importance of corneal biomechanical properties in IOP interpretation and should support further studies on the influence of CH and CCT in glaucoma screening and diagnosis.Objetivo: A literatura sugere que as propriedades biomecânicas da córnea, nomea-damente a espessura central da córnea (ECC) e a histerese corneana (HC), influenciam a medição da pressão intraocular (PIO). Este estudo teve como objetivo investigar a associação entre a ECC e a HC e o desenvolvimento de glaucoma. Métodos: Revisão da literatura e meta-análise. Foram incluídos estudos observacio-nais, publicados entre 2006 e 2016, que integrassem um grupo controle e um grupo de pacientes com glaucoma em que estes dois grupos apresentassem, igualmente, a ECC e a HC como parâmetros. Dezenove estudos foram considerados elegíveis e a diferença média (MD) daqueles parâmetros nos dois grupos foi utilizada para análise estatística. Resultados: Estudaram-se um total de 1.213 olhos com glaucoma e 1.055 olhos saudáveis. A análise quantitativa revelou que a HC é significativamente mais baixa no grupo de doentes com glaucoma quando comparada com o grupo controle (MD=-1,54 mmHg, intervalo de confiança de 95% [-1,68-1,41], P<0,00001). A ECC foi, também, significativamente mais baixa no grupo glaucoma quando comparada com os indivíduos saudáveis MD=-8,49 μm, intervalo de confiança de 95% [-11,36, -5,62], P<0,001). Conclusão: Os pacientes com glaucoma parecem possuir propriedades corneanas diferentes das que apresentam os indivíduos saudáveis. Os resultados enfatizam a importância das propriedades biomecânicas da córnea na interpretação da PIO e devem contribuir para novos estudos sobre a influência da HC e da ECC no rastreio e diagnóstico do glaucoma.info:eu-repo/semantics/publishedVersio