39,280 research outputs found

    Essays on monetary policy and financial stability

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    Doutoramento em EconomiaBy focusing on the relationship between financial stability and monetary policy for the cases of Chile, Colombia, Japan, Portugal and the UK, this thesis aims to add to the existing literature on the fundamental issue of the relationship between financial stability and monetary policy, a traditional topic that gained importance in the aftermath of the GFC as Central Banks lowered policy rates in an effort to rescue their economies. As the zero-lower bound loomed and the reach of traditional monetary policy narrowed, policy makers realised that alternative frameworks were needed and hence, macroprudential policy measures aimed at targeting the financial system as a whole were introduced. The second chapter looks at the relationship between monetary policy and financial stability, which has gained importance in recent years as Central Bank policy rates neared the zero-lower bound. We use an SVAR model to study the impact of monetary policy shocks on three proxies for financial stability as well as a proxy for economic growth. Monetary policy is represented by policy rates for the EMEs and shadow rates for the AEs in our chapter. Our main results show that monetary policy may be used to correct asset mispricing, to control fluctuations in the real business cycle and also to tame credit cycles in the majority of cases. Our results also show that for the majority of cases, in line with theory, local currencies appreciate following a positive monetary policy shock. Monetary policy intervention may indeed be successful in contributing to or achieving financial stability. However, the results show that monetary policy may not have the ability to maintain or re-establish financial stability in all cases. Alternative policy choices such as macroprudential policy tool frameworks which are aimed at targeting the financial system as a whole may be implemented as a means of fortifying the economy. The third chapter looks at the institutional setting of the countries in question, the independence of the Central Bank, the political environment and the impact of these factors on financial Abstract stability. I substantiate the literature review discussion with a brief empirical analysis of the effect of Central Bank Independence on credit growth using an existing database created by Romelli (2018). The empirical results show that there is a positive relationship between credit growth and the level of Central Bank Independence (CBI) due to the positive and statistically significant coefficient on the interaction term between growth in domestic credit to the private sector and the level of CBI. When considering domestic credit by deposit money banks and other financial institutions, the interaction term is positive and statistically significant for the case of the UK for the third regression equation. A number of robustness checks show that the coefficient is positive and statistically significant for a number of cases when implementing a variety of estimation methods. Fluctuations in credit growth are larger for higher levels of CBI and hence, in periods of financial instability or ultimately financial crises, CBI would be reined back in an effort to re-establish financial stability. Based on the empirical results, and in an effort to slow down surging credit supply and to maintain financial stability, policy makers and governmental authorities should attempt to decrease the level of CBI when the economy shows signs of overheating and credit supply continues to increase. The fourth chapter looks at the interaction between macroprudential policy and financial stability. The unexpected interconnectedness of the global economy and the economic blight that occurred as a result of this, recapitulated the need to implement an alternative policy framework aimed at targeting the financial system as a whole and hence, targeting the maintenance of financial stability. In this chapter, an index of domestic macroprudential policy tools is constructed and the effectiveness of these tools in controlling credit growth, managing GDP growth and stabilising inflation growth is studied using a dynamic panel data model for the period between 2000 and 2017. The empirical analysis includes two panels namely an EU panel of 27 countries and a Latin American panel of 7 countries, the chapter also looks at a case study of Japan, Portugal and the UK. Our main results find that a tighter macroprudential policy tool stance leads to a decrease in both credit growth and GDP growth while, a tighter macroprudential policy tool stance results in higher inflation in the majority of cases. Further, we find that capital openness plays a more important role in the case of Latin America, this may be due to the region’s dependence on foreign capital flows and exchange rate movements. Lastly, we find that, in times of higher perceived market volatility, GDP growth tends to be higher and inflation growth tends to be lower in the EU. In the other cases, higher levels of perceived market volatility result in higher inflation, higher credit growth and lower GDP Abstract growth. This is in line with expectations as an increase in perceived market volatility is met with an increased flow of assets into safer markets such as the EU. This thesis establishes a relationship between financial stability and monetary policy by studying the response of Chile, Colombia, Japan, Portugal and the UK in the aftermath of the GFC as Central Banks lowered policy rates in an effort to rescue their economies. In short, the results of the work conducted in this thesis may be summarised as follows. Our results show that monetary policy contributes to the achievement of financial stability. Still, monetary policy alone is not sufficient and should be reinforced by less traditional policy choices such as macroprudential policy tools. Secondly, we find that the level of CBI should be reined in in times of surging credit supply in an effort to maintain financial stability. Finally, we conclude that macroprudential policy tools play an important role in the achievement of financial stability. These tools should complement traditional monetary policy frameworks and should be adapted for each region.info:eu-repo/semantics/publishedVersio

    Search for heavy Majorana or Dirac neutrinos and right-handed WW gauge bosons in final states with charged leptons and jets in pppp collisions at s=13\sqrt{s}=13 TeV with the ATLAS detector

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    A search for heavy right-handed Majorana or Dirac neutrinos NRN_{\mathrm{R}} and heavy right-handed gauge bosons WRW_{\mathrm{R}} is performed in events with energetic electrons or muons, with the same or opposite electric charge, and energetic jets. The search is carried out separately for topologies of clearly separated final-state products (``resolved'' channel) and topologies with boosted final states with hadronic products partially overlapping and reconstructed as a large-radius jet (``boosted'' channel). The events are selected from pppp collision data at the LHC with an integrated luminosity of 139 fb‚ąí1^{-1} collected by the ATLAS detector at s\sqrt{s} = 13 TeV. No significant deviations from the Standard Model predictions are observed. The results are interpreted within the theoretical framework of a left-right symmetric model, and lower limits are set on masses in the heavy right-handed WRW_{\mathrm{R}} boson and NRN_{\mathrm{R}} plane. The excluded region extends to about m(WR)=6.4m(W_{\mathrm{R}}) = 6.4 TeV for both Majorana and Dirac NRN_{\mathrm{R}} neutrinos at m(NR)<1m(N_{\mathrm{R}})<1 TeV. NRN_{\mathrm{R}} with masses of less than 3.5 (3.6) TeV are excluded in the electron (muon) channel at m(WR)=4.8m(W_{\mathrm{R}})=4.8 TeV for the Majorana neutrinos, and limits of m(NR)m(N_{\mathrm{R}}) up to 3.6 TeV for m(WR)=5.2m(W_{\mathrm{R}}) = 5.2 (5.05.0) TeV in the electron (muon) channel are set for the Dirac neutrinos.Comment: 48 pages in total, author list starting page 31, 9 figures, 5 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2019-39

    Optimal universal quantum circuits for unitary complex conjugation

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    Let UdU_d be a unitary operator representing an arbitrary dd-dimensional unitary quantum operation. This work presents optimal quantum circuits for transforming a number kk of calls of UdU_d into its complex conjugate UdňČ\bar{U_d}. Our circuits admit a parallel implementation and are proven to be optimal for any kk and dd with an average fidelity of ‚ü®F‚ü©=k+1d(d‚ąík)\left\langle{F}\right\rangle =\frac{k+1}{d(d-k)}. Optimality is shown for average fidelity, robustness to noise, and other standard figures of merit. This extends previous works which considered the scenario of a single call (k=1k=1) of the operation UdU_d, and the special case of k=d‚ąí1k=d-1 calls. We then show that our results encompass optimal transformations from kk calls of UdU_d to f(Ud)f(U_d) for any arbitrary homomorphism ff from the group of dd-dimensional unitary operators to itself, since complex conjugation is the only non-trivial automorphisms on the group of unitary operators. Finally, we apply our optimal complex conjugation implementation to design a probabilistic circuit for reversing arbitrary quantum evolutions.Comment: 19 pages, 5 figures. Improved presentation, typos corrected, and some proofs are now clearer. Closer to the published versio

    Classical model emerges in quantum entanglement: Quantum Monte Carlo study for an Ising-Heisenberg bilayer

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    By developing a cluster sampling of stochastic series expansion quantum Monte Carlo method, we investigate a spin-1/21/2 model on a bilayer square lattice with intra-layer ferromagnetic (FM) Ising coupling and inter-layer antiferromagnetic Heisenberg interaction. The continuous quantum phase transition which occurs at gc=3.045(2)g_c=3.045(2) between the FM Ising phase and the dimerized phase is studied via large scale simulations. From the analyzes of critical exponents we show that this phase transition belongs to the (2+1)-dimensional Ising universality class. Besides, the quantum entanglement is strong between the two layers, especially in dimerized phase. The effective Hamiltonian of single layer seems like a transverse field Ising model. However, we found the quantum entanglement Hamiltonian is a pure classical Ising model without any quantum fluctuations. Furthermore, we give a more general explanation about how a classical entanglement Hamiltonian emerges

    One Small Step for Generative AI, One Giant Leap for AGI: A Complete Survey on ChatGPT in AIGC Era

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    OpenAI has recently released GPT-4 (a.k.a. ChatGPT plus), which is demonstrated to be one small step for generative AI (GAI), but one giant leap for artificial general intelligence (AGI). Since its official release in November 2022, ChatGPT has quickly attracted numerous users with extensive media coverage. Such unprecedented attention has also motivated numerous researchers to investigate ChatGPT from various aspects. According to Google scholar, there are more than 500 articles with ChatGPT in their titles or mentioning it in their abstracts. Considering this, a review is urgently needed, and our work fills this gap. Overall, this work is the first to survey ChatGPT with a comprehensive review of its underlying technology, applications, and challenges. Moreover, we present an outlook on how ChatGPT might evolve to realize general-purpose AIGC (a.k.a. AI-generated content), which will be a significant milestone for the development of AGI.Comment: A Survey on ChatGPT and GPT-4, 29 pages. Feedback is appreciated ([email protected]

    Synthesis, in vitro thymidine phosphorylase inhibitory activity and molecular docking study of novel pyridine-derived bis-oxadiazole bearing bis-schiff base derivatives

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    The current study has afforded twelve analogs (4a-l) of pyridine-derived bis-oxadiazole containing bis-schiff base and subsequently evaluated for their potential to inhibit thymidine phosphorylase(in vitro). All the synthesized analogs were structurally elucidated using various spectroscopic tools including NMR and HREIMS. All synthesized scaffolds showed varied range of inhibitory potential with IC50values ranging from 5.19¬†¬Ī¬†1.10 to 36.18¬†¬Ī¬†4.60¬†őľM in comparison to 7-deazaxanthine (IC50¬†=¬†30.28¬†¬Ī¬†2.10¬†őľM) as a standard drug. All analogs (except analog 4¬†l which displayed less potency than standard drug) showed improved potency having IC50 values of 19.73¬†¬Ī¬†2.30, 16.14¬†¬Ī¬†1.20, 18.93¬†¬Ī¬†1.60, 22.78¬†¬Ī¬†1.80, 30.47¬†¬Ī¬†3.70, 5.19¬†¬Ī¬†1.10, 23.13¬†¬Ī¬†1.90, 21.56¬†¬Ī¬†2.50, 4.88¬†¬Ī¬†1.10, 26.63¬†¬Ī¬†2.90 and 6.67¬†¬Ī¬†1.10 respectively.Results obatined were compared to standard 7-deazxanthine drug with IC50 values of 30.28¬†¬Ī¬†2.10¬†őľM. Structure-activity relationship (SAR) studies revealed that analogs bearing ‚ÄďNO2, -CF3, ‚ÄďOH and ‚ÄďCl moieties at various position of aryl part showed many folds more potency than standard 7-deazaxathine standard drug. In order to determine the potential mode of interactions with thymidine phosphorylase active sites, the most active analogs 4f (bearing 3-CF3& 5-NO2), 4i (bearing 3-OH &amp; 5-NO2), and 4¬†k (bearing 2-OH &5-NO2) were further subjected to molecular docking study. The results confirmed that these active analogs adopted numerous important interactions including hyrognen bonding, pi-donor hydrogen bond, pi-pi T shaped, pi-pi stacking, pi-alkyl, pi-anion, pi-sigma, halogen (flourine) and numerous Vander Waals interactions with the amino acid of enzyme being targeted

    International alliance of Urolithiasis (IAU) guideline on percutaneous nephrolithotomy

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    The International Alliance of Urolithiasis (IAU) would like to release the latest guideline on percutaneous nephrolithotomy (PCNL) and to provide a clinical framework for surgeons performing PCNL. These recommendations were collected and appraised from a systematic review and assessment of the literature covering all aspects of PCNLs from the PubMed database between January 1, 1976, and July 31, 2021. Each generated recommendation was graded using a modified GRADE methodology. The quality of the evidence was graded using a classification system modified from the Oxford Center for Evidence-Based Medicine Levels of Evidence. Forty-seven recommendations were summarized and graded, which covered the following issues, indications and contraindications, stone complexity evaluation, preoperative imaging, antibiotic strategy, management of antithrombotic therapy, anesthesia, position, puncture, tracts, dilation, lithotripsy, intraoperative evaluation of residual stones, exit strategy, postoperative imaging and stone-free status evaluation, complications. The present guideline on PCNL was the first in the IAU series of urolithiasis management guidelines. The recommendations, tips and tricks across the PCNL procedures would provide adequate guidance for urologists performing PCNLs to ensure safety and efficiency in PCNLs

    Simula√ß√£o de cen√°rios de fragilidade ambiental na bacia hidrogr√°fica do Rio da Prata, MS, utilizando o modelo de Cadeias Markov ‚Äď e aut√īmatos celulares

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    Utilizando t√©cnicas de geoprocessamento e sensoriamento remoto √© poss√≠vel analisar os diferentes impactos gerados ao meio ambiente ao longo dos anos, sendo portanto, uma importante ferramenta nos estudos da paisagem. Para complementar, a previs√£o da transi√ß√£o espacial e temporal dos impactos ambientais permite simular tend√™ncias futuras utilizando o modelo Cadeias de Markov e aut√īmatos celulares. O presente estudo tem como objetivo utilizar essas t√©cnicas descritas para entendimento da fragilidade ambiental da Bacia Hidrogr√°fica do Rio da Prata, MS, regi√£o com significativa import√Ęncia ambiental, caracterizada por fei√ß√Ķes c√°rsticas, gerando valor econ√īmico devido aos atrativos tur√≠sticos da regi√£o. Os resultados indicaram que a classe de fragilidade ‚Äúm√©dia‚ÄĚ e ‚Äúalta‚ÄĚ possuem maior converg√™ncia para aumento em detrimento da classe ‚Äúbaixa‚ÄĚ que teve maiores altera√ß√Ķes em diminui√ß√£o de sua √°rea, provavelmente devido ao uso da agricultura na regi√£o, que tem expandido ao longo dos anos estudados, aliado as caracter√≠siticas litol√≥gicas e pedol√≥gicas

    Economia colaborativa

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    A import√Ęncia de se proceder √† an√°lise dos principais desafios jur√≠dicos que a economia colaborativa coloca ‚Äď pelas implica√ß√Ķes que as mudan√ßas de paradigma dos modelos de neg√≥cios e dos sujeitos envolvidos suscitam ‚ąí √© indiscut√≠vel, correspondendo √† necessidade de se fomentar a seguran√ßa jur√≠dica destas pr√°ticas, potenciadoras de crescimento econ√≥mico e bem-estar social. O Centro de Investiga√ß√£o em Justi√ßa e Governa√ß√£o (JusGov) constituiu uma equipa multidisciplinar que, al√©m de juristas, integra investigadores de outras √°reas, como a economia e a gest√£o, dos v√°rios grupos do JusGov ‚Äď embora com especial participa√ß√£o dos investigadores que integram o grupo E-TEC (Estado, Empresa e Tecnologia) ‚Äď e de outras prestigiadas institui√ß√Ķes nacionais e internacionais, para desenvolver um projeto neste dom√≠nio, com o objetivo de identificar os problemas jur√≠dicos que a economia colaborativa suscita e avaliar se j√° existem solu√ß√Ķes para aqueles, refletindo igualmente sobre a conveni√™ncia de serem introduzidas altera√ß√Ķes ou se ser√° mesmo necess√°rio criar nova regulamenta√ß√£o. O resultado desta investiga√ß√£o √© apresentado nesta obra, com o que se pretende fomentar a continua√ß√£o do debate sobre este tema.Esta obra √© financiada por fundos nacionais atrav√©s da FCT ‚ÄĒ Funda√ß√£o para a Ci√™ncia e a Tecnologia, I.P., no √Ęmbito do Financiamento UID/05749/202
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