Littérature scientifique sur le sujet « Power law mutation rates »

The crossing time through fitness barrier in a symmetric multiplicative landscape is systematically calculated for various mutation rates, fitness parameters, and sequence lengths by using a computer simulation. It is found that the crossing time scales as a power law in the mutation rate and the fitness parameter. It is also found that the crossing time increases exponentially as the sequence length increases. We have obtained the approximate formula, which decribes the asymptotic behavior of the crossing time in the long-crossing-time region, and the improved approximate formula with the correction factor, which nicely fit computer simulation results even below the long-crossing-time region. From the comparison between the approximate formula in the multiplicative landscape and the approximate formula in the sharply-peaked landscape, it is found that both landscapes have the same scaling effect of fitness parameter and mutation rate on the crossing time in the long-crossing-time region.

This paper presents a robust instrument fault detection (IFD) scheme based on modified immune mechanism based evolutionary algorithm (MIMEA) that determines on line the optimal control actions, detects faults quickly in the control process, and reconfigures the controller structure. To ensure the capability of the proposed MIMEA, repeating cycles of crossover, mutation, and clonally selection are included through the sampling time. This increases the ability of the proposed algorithm to reach the global optimum performance and optimize the controller parameters through a few generations. A fault diagnosis logic system is created based on the proposed algorithm, nonlinear decision functions, and its derivatives with respect to time. Threshold limits are implied to improve the system dynamics and sensitivity of the IFD scheme to the faults. The proposed algorithm is able to reconfigure the control law safely in all the situations. The presented false alarm rates are also clearly indicated. To illustrate the performance of the proposed MIMEA, it is applied successfully to tune and optimize the controller parameters of the nonlinear nuclear power reactor such that a robust behavior is obtained. Simulation results show the effectiveness of the proposed IFD scheme based MIMEA in detecting and isolating the dynamic system faults.

Abstract Background: A difficulty associated with forensic applications is the detection of degraded biological materials. Due to the large amplicon sizes of short tandem repeat alleles, valid genotyping results cannot be obtained from degraded biological materials. Recently, insertion/deletion (InDel) polymorphisms have been used in forensic applications for their widespread distributions in the human genome, short amplicon sizes, and low mutation rates. Purpose: Human identification InDel panels have mostly been designed for European populations. Therefore, our laboratory independently developed a multiplex polymerase chain reaction (PCR) system with 35 polymorphic InDel loci to be used for human identification in China. Forensic validation studies were conducted on this novel 35-InDel multiplex PCR system. Methods: The 35 InDel loci were screened in the database, and then used with the traditional PCR amplification and capillary electrophoresis platform combined with five-color fluorescence parallel detection technology. Validation studies were performed on this novel panel, including accuracy, repeatability and reproducibility, species specificity, sensitivity, stability, forensic case sample detection, and mixture studies. In addition, forensic efficiency assessments were conducted in populations from different continents. Results: The data of validated studies indicated that the novel 35-InDel panel was accurate, stable, and efficient for forensic purposes. For human identification, the cumulative power of discrimination values for the these 35 InDel loci in East Asian, South Asian, European, American, and African populations were 0.999999999999995, 0.999999999999995, 0.999999999999971, 0.9999999999999960, and 0.999999999998166, respectively. Conclusions: In this study, a set of 35 InDel loci were conducted in a multiplex amplification system for human identification of degraded DNA sample, and this new assay was efficient and stable. The present results suggested that the 35-InDel panel was a reliable tool for forensic use and could be efficiently used for human identification in the East Asian populations.

Abstract The gold standard therapy for muscle-invasive bladder cancer (MIBC) is neoadjuvant chemotherapy followed by radical cystectomy (RC) and urinary diversion. Some patients may have their disease completely eradicated by chemotherapy as ~35% of patients achieve a pathologic complete response (pCR) when evaluated from RC specimens. RC with urinary diversion is a life-altering operation with high complication rates and therefore determining who are complete responders would improve quality of life and could decrease costs and still achieve a high cure rate via RC avoidance. Unfortunately, current methods cannot accurately identify complete responders. Our lab has developed a urine-based liquid biopsy test in which DNA isolated from urine and germline is isolated and subjected to panel exome sequencing for enumeration of somatic variants. This occurs under the premise that tumor DNA identified (as mutant alleles) is a marker of residual disease while the absence of tumor DNA (meaning the absence of mutant alleles) can indicate a pCR. A 55 gene panel was designed to be used for exonic sequencing of urinary DNA (uDNA) to identify mutations indicative of bladder cancer or therapeutic targets. We have shown that most mutations in tumor tissue are detectable as mutations in urine (Mu). We also showed that the presence or absence of residual Mu after completion of chemotherapy strongly associates with residual disease or pCR at the time of RC, respectively. Therefore, this test could be used after neoadjuvant therapy to better identify patients for RC avoidance. To optimize this test, we are currently evaluating pre-analytical factors affecting the yield, purity, and integrity of uDNA and the quality of sequencing data using prospectively collected samples from patients with MIBC. We are also testing commercial and novel preservatives to identify one that maintains cell-free DNA integrity, yield, and mutation detection accuracy to enable temporary ambient temperature storage without compromising mutation detection, permitting shipping/centralized testing. Lastly, we are comparing two library preparation approaches: classical hybrid capture-based (Agilent SureSelect XTHS) and amplicon+hybrid capture-based (Agilent HaloPlexHS) to determine which performs the best for identifying the variants in a sample. Our results showed that both sequencing depth and the quality bases mapped was higher when utilizing the SureSelect XTHS kit as compared to HaloPlexHS using approximately the same number of reads. This improvement may also increase the power to detect rare alleles. Studies described herein will enable liquid biopsy tests to accurately identify patients with pCR after neoadjuvant therapy and might safely avoid radical cystectomy. Citation Format: Rhea Arya, Henkel Valentine, Uttam Satyal, Raju Chelluri, Mengmeng Li, Philip Abbosh. Urine-based liquid biopsy test for the detection of residual bladder cancer in radical cystectomy patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3701.

This study introduces a data augmentation technique based on generative adversarial networks (GANs) to improve the accuracy of day-ahead wind power predictions. To address the peculiarities of abrupt weather data, we propose a novel method for detecting mutation rates (MR) and local mutation rates (LMR). By analyzing historical data, we curated datasets that met specific mutation rate criteria. These transformed wind speed datasets were used as training instances, and using GAN-based methodologies, we generated a series of augmented training sets. The enriched dataset was then used to train the wind power prediction model, and the resulting prediction results were meticulously evaluated. Our empirical findings clearly demonstrate a significant improvement in the accuracy of day-ahead wind power prediction due to the proposed data augmentation approach. A comparative analysis with traditional methods showed an approximate 5% increase in monthly average prediction accuracy. This highlights the potential of leveraging mutated wind speed data and GAN-based techniques for data augmentation, leading to improved accuracy and reliability in wind power predictions. In conclusion, this paper presents a robust data augmentation method for wind power prediction, contributing to the potential enhancement of day-ahead prediction accuracy. Future research could explore additional mutation rate detection methods and strategies to further enhance GAN models, thereby amplifying the effectiveness of wind power prediction.

Kramers escape rate theory is the most important one of modern reaction rate theories. However, one key assumption of the theory that thermodynamic equilibrium must prevail throughout the entire system studied is farfetched for open complex systems. Thereby, Kramers escape rates are generalized to describe rates of reactions in nonequilibrium systems with power-law distributions. Kramers escape rates in the very low damping systems, in overdamped systems and in the low-to-intermediate damping (LID) systems are investigated and the corresponding escape rates are obtained respectively on the basis of nonextensive statistics. When apply to biological, physical and chemical systems in each damping systems, these generalized escape rates with power-law distribution show a better agreement with experimental rates as compared with the traditional Kramers escape rates. It is expected that the generalized result can lead to an insight into the research on reaction rate theory for nonequilibrium complex systems with power-law distributions.

This paper presents a method on how to estimate main effects of gene representation. This estimate can be used not only to understand the domination of genes in the representation but also to design the mutation rate in genetic algorithms (GAs). A new approach of dynamic mutation rate is proposed by integrating the information of the main effects into the genes. By introducing the proposed method in GAs, both solution quality and solution stability can be improved in solving a set of parametrical test functions. The algorithm was applied to two illustrative applications to evaluate the performance of the proposed method, where the first application is on solving uncapacitated facility location problems and the next is on optimal power flow problems, which are employed. Results indicate that the proposed method yields significantly better results than the existing methods.

Cette thèse porte sur l'étude de deux modèles stochastiques liés à des problèmes médicaux. Le premier vise à comprendre le processus épidémique généré par des bactériophages coopératifs dans une population de bactéries résistantes aux antibiotiques. Pour cela, nous introduisons un modèle épidémiologique où les infections sont générées par la coopération de parasites dans une population d'hôtes structurée selon un modèle de configuration. Une transition de phase est observée pour la probabilité d'invasion dépendant du degré de connectivité des sommets et du nombre de parasites générés lors d'une infection d'un hôte. Au seuil critique, la probabilité d'invasion est identifiée comme la probabilité de survie d'un processus de Galton-Watson.Dans le but d'obtenir un modèle biologiquement plus pertinent, nous avons analysé un modèle similaire où une structure spatiale est ajoutée à la population d'hôtes en utilisant un "random geometric graph". Nous avons montré qu'une telle structure spatiale facilite la coopération des parasites. Une transition de phase similaire se produit où au seuil critique, des bornes supérieure et inférieure sont obtenues pour la probabilité d'invasion en tant que probabilités de survie de deux processus de branchement avec coopération.La deuxième question médicale concerne la compréhension de l'évolution de la composition génétique d'une tumeur en formation, en utilisant des processus de naissance et de mort multitypes branchants sur un espace de traits fini. Considérant une évolution neutre et délétère, nous fournissons des résultats au premier ordre asymptotique pour toutes les tailles des sous-populations mutantes. En particulier, nous capturons la stochasticité associée aux tailles des sous-populations mutantes lorsqu'une tumeur est observée cliniquement, et surtout nous caractérisons les chemins évolutifs effectifs, fournissant des informations sur le passé, le présent et le futur de l'évolution tumorale.Au-delà de ce cadre restrictif d'évolution neutre et délétère, nous proposons une nouvelle méthode pour comprendre le premier ordre asymptotique du premier trait mutant sélectif
This thesis focuses on the study of two stochastic models related to medical problems. The first one lies on understanding infection spread of cooperating bacteriophages on a structured multi-drug resistant bacterial host population. Motivated by this example, we introduce an epidemiological model where infections are generated by cooperation of parasites in a host population structured on a configuration model. We analysed the invasion probability for which we obtain a phase transition depending on the connectivity degree of the vertices and the offspring number of parasites during an infection of a host. At the critical scaling, the invasion probability is identified as the survival probability of a Galton-Watson process. With the aim to get a biological more relevant model, we analysed a similar model where a spatial structure is added for the host population using a random geometric graph. We have shown that such spatial structure facilitates cooperation of parasites. A similar phase transition occurs where at the same critical scaling the invasion probability is upper and lower bounded by the survival probabilities of two discrete branching processes with cooperation. The second medical question deals with understanding the evolution of the genetic composition of a tumor under carcinogenesis, using multitype birth and death branching process models on a general finite trait space. In the case of neutral and deleterious cancer evolution, we provide first-order asymptotics results on all mutant subpopulation sizes. In particular such results capture the randomness of all cell trait sizes when a tumor is clinically observed, and mostly it allows to characterize the effective evolutionary pathways, providing information on the past, present, and future of tumor evolution.Moving beyond this restrictive neutral and deleterious cancer evolution framework, we provide a new method to understand the first selective mutant trait size

The thesis explains the theory of purchasing power parity and related concepts. It shows differences in prices and wages all around the globe and gives theoretical explanation of existing disparities. The goal is to find out how prices differ in reality, where costs of living are the highest or the lowest and what makes some products more or less expensive in different countries. In order to answer the questions the thesis deals with, the variety of sources was used, starting from economics textbooks, academic journals, literature reviews, the Economist website, a study of UBS 'Prices and Earnings', International Monetary Fund database and others.

Why are the US and China regulating cryptocurrency? This paper first uses linear regression to model the relationship between the US dollar and Bitcoin, and separately, the Chinese Renminbi and Bitcoin. Next, legal text is analyzed to make the comparative case for the United States' and China's legal responses to new advances in cryptocurrency, and how it shows threats to the traditional definition and control of currency.

Made available in DSpace on 2016-03-15T19:34:38Z (GMT). No. of bitstreams: 1 Daniel Francisco Nagao Menezes.pdf: 645905 bytes, checksum: 4da0034cd233111d2733777cc62d3351 (MD5) Previous issue date: 2008-08-08
It is a dissertation that deals with the issue of Constitutional Change in order to analyze the integration of Law and Economics and; the divergence which has emerged from this kind of integration explained by the different times of evolution between Law and Economics. Bringing a review about the Constitutional changes since the appearance of the problems involving disparity between social reality and the Law, established by Ferdinand Lassalle, until the integrative theories of the Constitution, those bring into themselves the social divergence accepting by that a constant mutability, so they are, necessarily, political stuff. Finally, it proposes the existence of an active Constitutional Change, different of the others classic cases of Constitutional changes, manipulated according to the wishes of the Economic Power.
Dissertação de mestrado que trata da questão da Mutação Constitucional a fim de analisar a integração entre Direito e Economia e, a divergência surgida nessa integração a partir da existência de tempos evolutivos diferentes entre Direito e Economia. Traz revisão bibliográfica sobre a Mutação Constitucional desde o surgimento do problema das disparidade entre realidade social e Direito, constatado por Ferdinand Lassalle, até as teorias integrativas da Constituição, as quais trazem para dentro de si as divergências sociais aceitando com isso uma constante mutabilidade, o que as torna necessariamente políticas. Por fim propõe a existência de uma Mutação Constitucional ativa, a qual diferente dos casos clássico de Mutação Constitucional, são manipuladas segundo as vontades do Poder Econômico.

Östersjön har alltid varit en viktig knutpunkt för de länder som angränsar dit för att göra det möjligt att handla med varandra och på så sätt skapa en internationell marknad sinsemellan varandra. Under 1700-1800-talet tog produktionen fart och tack vare merkantilismen utvecklades den internationella handeln. För att fastställa deras växelkurs har många länder använt sig av olika myntfot såsom till exempel guldmyntfoten där valutans värde bestämdes utifrån värdet på motsvarande mängd guld vilket innebär att växelkurserna var fasta. Utifrån guldmyntfoten utvecklades teorierna lagen om ett pris och köpkraftsparitet med principerna om att en enhet valuta ska ha samma köpkraft även i andra länder vilket innebär att en vara ska kunna köpas för samma mängd av valutan oavsett om det är inrikes eller utrikes. Dessa teorier har studerats flertalet gånger, både för kort och lång sikt, med fåtalet länder till ett större antal. Denna studie använder sig av teoriernas grundidé och testar huruvida PPP i dess absoluta samt relativa form håller för Östersjöns handelsområde. För att kunna testa detta har två ekonometriska tester av de variabler som används gjorts, stationäritetstest och kointegrationstest. Stationäritetstestet visade att alla variabler förutom de tidsserier som användes för att testa relativ PPP led av icke-stationäritet och därmed behövdes differentieras för att kunna användas för att testa PPP. Kointegrationstestet visade att ingen av tidsserierna led av kointegration vilket medförde att vidare korrigeringsmodeller ej behövdes göras. Resultatet från de ekonometriska skattningarna visade på att absolut och relativ PPP ej kunde bekräftas, ej heller förnekas, då inga signifikanta koefficienter kunde konstateras. Vid testandet av real växelkurs för relativ PPP gavs signifikanta tidsserier men ej i enlighet med nollhypotesen och därmed förkastades nollhypotesen om att relativ PPP håller. Utifrån resultatet dras slutsatsen att PPP ej kan bekräftas utan att vidare studier måste göras.
The Baltic sea has always been an important transit hub for neighboring countries and the sea have made ​​it possible for the countries to trade with each other and thus create an international trade among themselves to each other. During 1700-1800's, the production took off and because of the mercantilism international trade developed. To establish their exchange rate, many countries have followed different standards, such as the gold standard where the currency's value was determined from the value of the corresponding quantity of gold which implies that the exchange rates were fixed. Based on the gold standard different theories was developed, such as the law of one price and purchasing power parity with the principles that a single currency will have the same purchasing power in other countries, which implies that a commodity should be bought for the same amount of currency, whether it is domestic or foreign. These theories have been studied several times, both for the short and long term, with the few countries to a greater number. In order to test this, two econometric tests of the variables were made​​, stationarity test and cointegration test. The stationarity test showed that all variables except the time series that was used to test relative PPP suffered from non-stationarity and therefore needed to be differentiated to be used to test the PPP. The cointegration test showed that no one of the time series suffered of cointegration and therefore further correction models was not needed to be done. The results from the econometric estimates showed that absolute and relative PPP could not be confirmed, nor denied, since no significant coefficients were identified. In the testing of real exchange rate for relative PPP significant time series were given but not in accordance with the nullhypothesis and therefore the null hypothesis is rejected that the relative PPP holds. From the results it is concluded that the PPP cannot be confirmed without that further studies must be done.

In present finite element study, the dynamics of incompressible isothermal flows of Newtonian and two generalised non-Newtonian models through complex mixing-separating planar channel and circular pipe filled with and without porous media, including Darcy's term in momentum equation, is presented. Whilst, in literature this problem is solved only for planar channel flows of Newtonian and viscoelastic fluids. The primary aim of this study is to examine the laminar flow behaviour of Newtonian and inelastic non-Newtonian fluids, and investigate the robustness of the numerical algorithm. The rheological properties of non-Newtonian fluids are defined utilising a range of constitutive equations, for inelastic non-Newtonian fluids non-linear viscous models, such as Power Law and Bird-Carreau models are used to capture the shear thinning behaviour of fluids. To simulate such complex flows, steady-state solutions are sought employing time-dependent finite element algorithm. Temporal derivatives are discretised using second order Taylor series expansion, while, spatial discretisation is achieved through Galerkin approximation in combination to deal with incompressibility a pressure-correction scheme adopted. In order to achieve the algorithm of semi-implicit form Darcy's-Brinkman equation is utilized for the conversion in Darcy's terms and diffusion, while Crank-Nicolson approach is adopted for stability and acceleration. Simple and complex flows for various complex flow bifurcations of the combined mixing-separating geometries, for both two-dimensional planar channel in Cartesian coordinates, as well as axisymmetric circular tube in cylindrical polar coordinates system are investigated. These geometries consist of a two-inverted channel and pipe flows connected through a gap in common partitions, initially filled with non-porous materials and later with homogeneous porous materials. Computational domain is having variety it has been investigated with many configurations. These computational domains have been appeared in industrial applications of combined mixing and separating of fluid flows both for porous and non-porous materials. Fully developed velocity profile is applied on both inlets of the domain by imposing analytical solutions found during current study for porous materials. Numerical study has been conducted by varying flow rates and flow direction due to a variety in the domain. The influence of varying flow rates and flow directions are analysed on flow structure. Also the impact of increasing inertia, permeability and power law index on flow behaviour and pressure difference are investigated. From predicted solution of present numerical study, for Newtonian fluids a close agreement is realised between numerical solutions and experimental data. During simulations, it has been noticed that enhancing fluid inertia (flow rates), and permeability has visible effects on the flow domains. When the Reynolds number value increases the size and power of the vortex for recirculation increases. Under varying flow rates an early activity of vortex development was observed. During change in flow directions reversed flow showed more inertial effects as compared with unidirectional flows. Less significant influence of inertia has been observed in domains filled with porous media as compared with non-porous. The power law model has more effects on inertia and pressure as compared with Bird Carreau model. Change in the value of permeability gave significant impact on pressure difference. Numerical simulations for the domain and fluids flow investigated in this study are encountered in the real life of mixing and separating applications in the industry. Especially this purely quantitative numerical investigation of flows through porous medium will open more avenues for future researchers and scientists.

A South African taxpayer’s taxable income must be determined in rands. Several provisions of the Income Tax Act (the Act) relate to foreign currency transactions and the interaction of these provisions is complicated. A taxpayer needs to determine the provision that applies to his foreign transaction. It will then provide the rule or method that needs to be applied to his foreign transaction. If an amount is in a foreign currency, it must be translated into rands. If there is an exchange item, a foreign exchange gain or foreign exchange loss must be taken into account. If an asset is disposed of or acquired in a foreign currency then a capital gain or capital loss must be calculated when it is disposed of. Examples of typical foreign exchange transactions have been provided, discussed and analysed in this dissertation. The provisions in the Act that are relevant to the foreign exchange transactions have been identified and the interaction between them has been considered. Potential difficulties because provisions in the legislation contradict each other or do not cater for a particular situation were identified. Also possible tax-saving opportunities have been identified.
Thesis (M.Acc.)-University of KwaZulu-Natal, Westville, 2010.

We consider a general preferential attachment model, where the probability that a newly arriving vertex connects to an older vertex is proportional to a (sub-)linear function of the indegree of the older vertex at that time. We provide a limit theorem with rates of convergence for the distribution of a vertex, chosen uniformly at random, as the number of vertices tends to infinity. To do so, we develop Stein's method for a new class of limting distributions including power-laws. Similar, but slightly weaker results are shown to be deducible using coupling techniques. Concentrating on a specific preferential attachment model we also show that the outdegree distribution asymptotically follows a Poisson law. In addition, we deduce a central limit theorem for the number of isolated vertices. We thereto construct a size-bias coupling which in combination with Stein’s method also yields bounds on the distributional distance.

The US airline industry is going through a period of consolidation through mergers between leading airlines. A number of recent mergers have been approved by the Antitrust Division of the Department of Justice (DOJ) based on the presence of Southwest Airlines in merger-affected markets. In doing so, the DOJ makes a key assumption that Southwest is unresponsive to the reduced competition when its competitors merge. We find that Southwest raised fares more in markets where Delta/Northwest and US/America-West used to operate jointly between 2005-2010. However, Southwest's fares either decreased or rose by less if facing direct or adjacent competition from a low-cost carrier (LCC). Furthermore, Southwest is now merging with AirTran Airways, its biggest LCC competitor. This implies that the DOJ should not rely on Southwest Airlines as a post-merger deterrent to fare increases.
Graduation date: 2012

This paper presents a robust instrument fault detection (IFD) scheme based on modified immune mechanism based evolutionary algorithm (MIMEA) that determines on line the optimal control actions, detects faults quickly in the control process, and reconfigures the controller structure. To ensure the capability of the proposed MIMEA, repeating cycles of crossover, mutation, and clonally selection are included through the sampling time. This increases the ability of the proposed algorithm to reach the global optimum performance and optimize the controller parameters through a few generations. A fault diagnosis logic system is created based on the proposed algorithm, nonlinear decision functions, and its derivatives with respect to time. Threshold limits are implied to improve the system dynamics and sensitivity of the IFD scheme to the faults. The proposed algorithm is able to reconfigure the control law safely in all the situations. The presented false alarm rates are also clearly indicated. To illustrate the performance of the proposed MIMEA, it is applied successfully to tune and optimize the controller parameters of the nonlinear nuclear power reactor such that a robust behavior is obtained. Simulation results show the effectiveness of the proposed IFD scheme based MIMEA in detecting and isolating the dynamic system faults.

The models discussed in the last chapter are intriguing, but present a number of problems. In particular, most of the results about them come from computer simulations, and little is known analytically about their properties. Results such as the power-law distribution of extinction sizes and the system's evolution to the "edge of chaos" are only as accurate as the simulations in which they are observed. Moreover, it is not even clear what the mechanisms responsible for these results are, beyond the rather general arguments that we have already given. In order to address these shortcomings, Bak and Sneppen (1993; Sneppen et al. 1995; Sneppen 1995; Bak 1996) have taken Kauffman's ideas, with some modification, and used them to create a considerably simpler model of large-scale coevolution which also shows a power-law distribution of avalanche sizes and which is simple enough that its properties can, to some extent, be understood analytically. Although the model does not directly address the question of extinction, a number of authors have interpreted it, using arguments similar to those of section 1.2.2.5, as a possible model for extinction by biotic causes. The Bak-Sneppen model is one of a class of models that show "self-organized criticality," which means that regardless of the state in which they start, they always tune themselves to a critical point of the type discussed in section 2.4, where power-law behavior is seen. We describe self-organized criticality in more detail in section 3.2. First, however, we describe the Bak-Sneppen model itself. In the model of Bak and Sneppen there are no explicit fitness landscapes, as there are in NK models. Instead the model attempts to mimic the effects of landscapes in terms of "fitness barriers." Consider figure 3.1, which is a toy representation of a fitness landscape in which there is only one dimension in the genotype (or phenotype) space. If the mutation rate is low compared with the time scale on which selection takes place (as Kauffman assumed), then a population will spend most of its time localized around a peak in the landscape (labeled P in the figure).

Abstract Louis XIV and his advisers, Mazarin and Colbert, believed that a nation‘s wealth (and not incidentally its power) depended on its store of gold and silver. The way to increase that store would be to maximize exports paid for in hard currency, and to limit imports. The heritage of that belief, generally referred to as mercantilism, has survived, even when the theory has failed to withstand analysis. Nations still seek to promote exports and restrain imports by a variety of means, and when they lower barriers to imports, for instance by reducing tariffs, they think of such action as concessions. A brief introduction to the role of international exchange and payments is presented here, as a complement to the discussion of the theory of international trade introduced in Chapter 1. The legal rules of the international monetary system are discussed in Part VII.

Abstract Evolution depends ultimately on the population-genetic environment, defined by mutation and recombination rates and the power of random genetic drift. The latter, which is an inverse function of the effective population size, defines the noise in evolutionary dynamics. If the power of drift exceeds the deterministic force of selection, the latter is rendered ineffective, resulting in patterns of evolution entirely determined by mutational forces. These issues are central to understanding evolutionary processes because all three major forces vary by about four orders of magnitude across the Tree of Life. Moreover, the mutation rate evolves to become inversely related to the effective population size, so populations experiencing greater drift simultaneously experience increased mutational pressure. In addition, average rates of recombination per nucleotide site decline in larger organisms, which evolve larger chromosomes owing to the accumulation of large amounts of non-functional DNA, but still experience just one to two crossover events per chromosome arm during meiosis. This covariation of rates of mutation, recombination, and drift across the Tree of Life influences the ways in which different lineages evolve in response to natural selection, in effect creating drift barriers beyond which selection cannot proceed. In large multicellular organisms with small effective population sizes, natural selection is constrained to utilize mutations with relatively large effects, whereas microbes with large effective population sizes are capable of discriminating mutations with very tiny effects, opening up the capacity for more fine-grained evolution.

This chapter addresses the question of why a theory of constituent power in the EU is needed. While the EU has long since taken on a constitutional character, this is in no way reflected in adequate popular participation in decisions about its basic legal order. The EU is shaped through a combination of intergovernmental treaty making and integration through law that sidelines citizens. Constitutional mutation further decouples the EU’s constitutional development from popular control and shields fundamental decisions from democratic contestation. To capture the legitimacy gap that opens up here, the chapter introduces an understanding of constituent power as political autonomy at the level of constitutional politics. It argues that European integration is based on a usurpation, with constituted powers operating as de facto constituent powers. As executives and courts shape the EU in a largely self-referential manner, citizens are deprived of a crucial dimension of political autonomy. The chapter concludes with preliminary considerations on a theory of constituent power in the EU, addressing substantive and methodological challenges involved in its elaboration, as well as possible objections to the project as such.

This chapter examines Article 16 of the United Nations Convention on the Rights of Persons with Disabilities (CRPD). That disabled people experience higher rates of exploitation, violence, and abuse is an undisputed fact. Indeed, it is a significant problem globally which requires immediate redress and, on this basis, the framing of the issue as a specific human right with detailed attendant obligations is important. Article 16 calls for an awareness that measures put in place to care for or protect disabled people can be a significant cause of the harm that they experience, and that segregation and isolation from the community allow for abuses of power by those who are supposed to be caring for disabled people. Article 16 also extends state obligations beyond the narrow purview of institutions and into a wider variety of arenas, including family relationships and private homes.

The huge financial rewards that may be gained from software sales have resulted in computer piracy, an increasing worldwide phenomenon. This situation has posed a challenge to the legislator, who has imposed regulations concerning the protection of software, both at national and international level. The following chapter focuses on the presentation of the current Hellenic legal framework on computer program copyright protection following the implementation of the relative E.U. Directives (Law 2121/1993, as amended). The chapter consists of an introduction focusing on software piracy rates and on the international legal framework of the protection; there is a unit on the right holder, being the subject of software copyright protection; a unit on the field of the protection; a unit on the rights of the author (the moral right, the property right and the resulting powers thereof), focusing on the power of software reproduction and specific cases where the lawful user can carry out acts without the author’s consent; a unit on the consequences of copyright infringement (sanctions at civil, criminal, and administrative level); a unit on the duration of the protection; and finally concluding with final remarks and recommendations.

Bounded randomness of mass/energy exchange rates neither presuppose nor selects any specific time scale, thresholds of stability included. Nonetheless, the boundedness of the rates sets certain non-physical correlations among successive increments and thus justifies formation of “sub-walks” on the finest scale. Further, the “U-turns” at the thresholds of stability set certain correlations on the biggest possible scale of a relevant variable. The major question now is how the balance between the universal correlations, set by the “U-turns,” and those of the specific “sub-walks,” set by the bounded randomness, shapes the structure of a BIS that represents the evolutionary pattern of a relevant variable. It is proven that this issue is inherently related to another universal property of complex systems behavior that is power law distributions. It is demonstrated that power law distributions acquire novel understanding in the setting of boundedness: they appear as universal criterion for hierarchical structuring implemented under boundedness.

This chapter details the identification of rate laws, which is the first step in the process of understanding how chemical reactions occur and is an essential step in predicting how the composition of a reaction mixture changes with time. The rate of reaction is often found to be proportional to the molar concentrations of the reactants raised to a simple power. The rate constant is independent of the concentrations of the species taking part in the reaction but depends on the temperature. An experimentally determined equation of this kind is called the ‘rate law’ of the reaction. A rate law provides a basis for the classification of reactions according to their kinetics. The chapter then differentiates between pseudofirst-order and pseudosecond-order rate law, and considers the determination of a rate law through the isolation method and the method of initial rates.

Copper alloyed with 50 ppm phosphorus (Cu-OFP) is selected for canisters for nuclear waste packages to avoid a low creep ductility, which is sometimes present in pure copper. The operating temperatures of these canisters are in the range from 0 to 100°C. Creep readily takes place in copper even at room temperature. At temperatures below 100°C, creep is well inside the power-law breakdown regime. The creep exponent is in the range from 30 to 100. Since creep models for this situation are missing in the literature, a new model for the minimum creep rate based on fundamental principles for climb and glide has been derived. This model gives the correct order of magnitude for the creep rate in the temperature range from 20 to 400°C without the use of fitted parameters. Design against creep can either be based on the total applied stress or the effective stress. In the first case the constitutive equations can be directly obtained from the minimum experimental creep rates. A new approach is proposed to handle the effective stress case, which is based on the initial creep rates. The φ-model is used to relate the initial creep rate to the minimum one. It is shown how the constitutive equations for the creep rate and the back stress can be transferred to multiaxial stress states for use in FE-modelling.

For the application of waste heat recovery (WHR), supercritical CO2 (S-CO2) Brayton power cycles offer significant suitable advantages such as compactness, low capital cost and applicable to a broad range of heat source temperatures. The current study is focused on thermodynamic modelling and optimization of Recuperated (RC) and Recuperated Recompression (RRC) S-CO2 Brayton cycles for exhaust heat recovery from a next generation heavy duty simple cycle gas turbine using a genetic algorithm. The Genetic Algorithm (GA) is mainly based on bio-inspired operators such as crossover, mutation and selection. This non-gradient based algorithm yields a simultaneous optimization of key S-CO2 Brayton cycle decision variables such as turbine inlet temperature, pinch point temperature difference, compressor pressure ratio. It also outputs optimized mass flow rate of CO2 for the fixed mass flow rate and temperature of the exhaust gas. The main goal of the optimization is to maximize power out of the exhaust stream which makes it single objective optimization. The optimization is based on thermodynamic analysis with suitable practical assumptions which can be varied according to the need of user. Further the optimal cycle design points are presented for both RC and RRC configurations and comparison of net power output is established for waste heat recovery.

The transport of Non-Newtonian fluids through pipelines and mud circulation in wellbores often occur in turbulent flow regimes. In this study, experiments and computational fluid dynamics (CFD) models are used to examine the influence of yield power law (YPL) fluid rheological properties on pressure loss in the flow loop in turbulent flow. Three Non-Newtonian fluids at different concentrations of Xanthan gum solutions (0.05%, 0.10% and 0.15%, by weight) are studied at flow rates ranging between 400 and 800 L/min. A fully instrumented flow loop system was used, consisting of three main sections of different inclinations: 5 m long horizontal, 5 m vertical, and 3 m inclined 45° test section. Additionally, CFD codes of ANSYS CFX 17.2 are examined and compared to experimental results. These models are based on the Reynolds Averaged Navier-Stokes (RANS) equations. The comparison is done with the results of these investigations, based on vertical and horizontal pipe frictional pressure drops. The results show that the gap between experimental and CFD models has been increased in comparison with increase concentration Xanthan gum solution at the same density of fluids. Specifically, pressure loss rises with rises in the consistency index, k and flow behaviour index, However, rises in yield stress τ0 showed less impacts on frictional pressure losses. Given these simulation outcomes, it is clear that pressure drop in the Non-Newtonian fluid in one phase flow can be more accurately predicted by used the Reynolds-Stress Models (RSM) more than Eddy-viscosity models.

An exergy framework was developed taking into consideration a detailed analysis of the heat exchanger (intercooler) component irreversibilities. Moreover, it was further extended to include an adequate formulation for closed systems, e.g. a secondary cycle, moving with the aircraft. Afterwards the proposed framework was employed to study two radical intercooling concepts. The first proposed concept uses already available wetted surfaces, i.e. nacelle surfaces, to reject the core heat and contribute to an overall drag reduction. The second concept uses the rejected core heat to power a secondary organic Rankine cycle and produces useful power to the aircraft-engine system. Both radical concepts are integrated into a high bypass ratio turbofan engine, with technology levels assumed to be available by year 2025. A reference intercooled cycle incorporating a heat exchanger in the bypass duct is established for comparison. Results indicate that the radical intercooling concepts studied in this paper show similar performance levels to the reference cycle. This is mainly due to higher irreversibility rates created during the heat exchange process. A detailed assessment of the irreversibility contributors, including the considered heat exchangers and the secondary cycle major components is made. A striking strength of the present analysis is the assessment of the component irreversibility rate and its contribution to the overall aero-engine losses.

In this work, the statistical methods for the reliability of repairable systems have been used to produce a methodology capable to estimate the annualized failure rate of a pipeline population from the historical failure data of multiple pipelines systems. The proposed methodology provides point and interval estimators of the parameters of the failure intensity function for two of the most commonly applied stochastic models; the homogeneous Poisson process and the power law process. It also provides statistical tests to assess the adequacy of the stochastic model assumed for each system and to test whether all systems have the same model parameters. In this way, the failure data of multiple pipeline systems are only pooled to produce a generic failure intensity function when all systems follow the same stochastic model. This allows addressing both statistical and tolerance uncertainty adequately. The proposed methodology is outlined and illustrated using real life failure data of multiple oil and gas pipeline systems.

Some industrials processes are associated with flow of non-Newtonian fluids in annular spaces. Examples are found in oil industry and food industrial processing. In some cases, gravitational forces cause internal pipe deflection and, consequently, the eccentricity changes along of axis of the annular space. So, flow patterns are modified respect to those found in constant eccentricity annular spaces. Current industrial practice consists on extrapolate predictions based on flow patterns from the constant eccentricity critical scenario, corresponding to the critical region where both boundaries are closer, to the variable eccentricity actual scenario. In practice, using this approach, flow pattern predictions could significantly deviate from the actual profile, and variables such as shear stress at walls or pressure gradient could not be estimated with adequate accuracy. This work consists of a Computational Fluid Dynamics study, aimed to state the implications of evaluating flow patterns, assuming constant eccentricity, in opposition to a more realistic scenario, considering deflection path along the annular space, using a commercial code. A particular application is made to mud removal during well cementing operations in oil industry. For the casing in the hole, the deflection equation is solved and eccentricity along of the system axis is found. Flow of a non-Newtonian fluid described by Power Law model is considered. Oil industry typical conditions are considered for fluid density, rheological parameters, flow rates, casing and hole sizes, and annulus eccentricity. The flow regime was considered laminar. Numerical model capability to reproduce accurately flow patterns in these conditions was assured by comparison with others analytical-numerical solutions for concentric systems. Results show that local Reynolds number Re, shear stress τw and pressure gradient predictions G, under local eccentricity variations, differ from those under constant eccentricity. Differences in Re and τw show a maximum for eccentricity ranging from 60% to 80%, for all flow conditions whereas for G, this difference increases as casing deflection does it. When variable eccentricity models are compared to constant eccentricity one, the latter approach underestimates Re and τw along the narrowest section of the annuli, whereas overestimates the same features along the widest clearance. Additionally, considerably higher variations between these two models are taking place along the narrowest section compared to the variations arising on the widest annular section. When applied to well cementing processes, these results show that considering the most realistic scenario may impact significantly the flow pattern prediction on the annulus during primary cementing operations. Therefore, the quality of the cement job may be greatly compromised.

This paper presents an method for heat rate monitoring of power plants which employs a true “systems approach”. As an ultimate monitoring parameter, derived from Second Law concepts, it quantifies system losses in terms of fuel consumption by individual components and processes. If electricity is to be produced with the least un-productive fuel consumption, then thermodynamic losses must be understood and minimized. Such understanding cuts across vendor curves, plant design, fuels, Controllable Parameters, etc. This paper demonstrates that thermal losses in a nuclear unit and a trash burner are comparable at a prime facia level. The Second Law offers the only foundation for the study of such losses, and affords the bases for a true and ultimate indicator of system performance. From such foundations, a Fuel Consumption Index (FCI) was developed to indicate specifically what components or processes are thermodynamically responsible for fuel consumption. FCIs tell the performance engineer why fuel is being consumed, quantifying that a portion of fuel which must be consumed to overcome frictional dissipation in the turbine cycle (FCITCycle), the combustion process (FCIComb), and so forth; and, indeed, how much fuel is required for the direct generation of electricity (FCIPower). FCIs have been particularly applicable for monitoring power plants using the Input/Loss Method. FCIs, Δheat rates based on FCIs, and an “applicability indicator” for justifying the use of Reference Bogey Data are all defined. This paper also presents the concept of “dynamic heat rate”, based on FCIs, as a parameter by which the power plant operator can gain immediate feedback as to which direction his actions are thermally headed: towards a lower or higher heat rate.

Research on individual variation of the filtration and growth rates of mussels was based both on the authors’ field and laboratory experiments and literature data analysis. High individual variability of these characteristics was recorded during the tests. The coefficient of variation grew up as the mean rate diminished. Under low specific growth rate the coefficient of variation (ratio of root-mean-square deviation to the sample mean) could exceed 100 %. Tests revealed the power-law relation of the coefficient of variation from the average for studied characteristics. That relation could be seen in filtration and growth rate charts; it was also true for estimates of production energy and metabolic costs. The exponent varied from -0.36 to -0.77. Individual growth rate variation of mussels was concluded to be an important criterion of the favorability of environmental conditions.

Research on individual variation of the filtration and growth rates of mussels was based both on the authors’ field and laboratory experiments and literature data analysis. High individual variability of these characteristics was recorded during the tests. The coefficient of variation grew up as the mean rate diminished. Under low specific growth rate the coefficient of variation (ratio of root-mean-square deviation to the sample mean) could exceed 100 %. Tests revealed the power-law relation of the coefficient of variation from the average for studied characteristics. That relation could be seen in filtration and growth rate charts; it was also true for estimates of production energy and metabolic costs. The exponent varied from -0.36 to -0.77. Individual growth rate variation of mussels was concluded to be an important criterion of the favorability of environmental conditions.

Abstract Most engineering components are subjected to cyclic loading in service and design against fatigue failure is often a key consideration in design. For fracture mechanics fatigue analysis, fatigue crack growth (FCG) tests are often required to determine the relevant Paris power law parameters for the material under the environment concerned. Standards allow use of different specimen geometries for FCG tests such as compact tension (CT), centre crack tension (CCT), single edge notch bend (SENB) and single edge notch tension (SENT). However, when selecting specimen geometry for fatigue crack growth rate (FCGR) testing, there is often doubt about which specimen geometry is more appropriate and whether they give similar FCGR. There is limited work to compare the FCGR between different specimen geometries. This paper first briefly introduces the guidance on FCG test specimen geometries in standards and compares the advantages and disadvantages of these specimen geometries. A comprehensive literature review is carried out to compare the FCGR data between different specimen geometries. FCGR tests are conducted on SENB, SENT and CCT specimens of C-Mn steel to investigate any effects of specimen symmetry/asymmetry and crack constraint on FCGR. Based on the literature review and test data, it is concluded that FCGR is independent of the specimen geometries examined.

Banco de la República is celebrating its 100th anniversary in 2023. This is a very significant anniversary and one that provides an opportunity to highlight the contribution the Bank has made to the country’s development. Its track record as guarantor of monetary stability has established it as the one independent state institution that generates the greatest confidence among Colombians due to its transparency, management capabilities, and effective compliance with the central banking and cultural responsibilities entrusted to it by the Constitution and the Law. On a date as important as this, the Board of Directors of Banco de la República (BDBR) pays tribute to the generations of governors and officers whose commitment and dedication have contributed to the growth of this institution.1 Banco de la República’s mandate was confirmed in the National Constitutional Assembly of 1991 where the citizens had the opportunity to elect the seventy people who would have the task of drafting a new constitution. The leaders of the three political movements with the most votes were elected as chairs to the Assembly, and this tripartite presidency reflected the plurality and the need for consensus among the different political groups to move the reform forward. Among the issues considered, the National Constitutional Assembly gave special importance to monetary stability. That is why they decided to include central banking and to provide Banco de la República with the necessary autonomy to use the instruments for which they are responsible without interference from other authorities. The constituent members understood that ensuring price stability is a state duty and that the entity responsible for this task must be enshrined in the Constitution and have the technical capability and institutional autonomy necessary to adopt the decisions they deem appropriate to achieve this fundamental objective in coordination with the general economic policy. In particular, Article 373 established that “the State, through Banco de la República, shall ensure the maintenance of the purchasing power of the currency,” a provision that coincided with the central banking system adopted by countries that have been successful in controlling inflation. In 1999, in Ruling 481, the Constitutional Court stated that “the duty to maintain the purchasing power of the currency applies to not only the monetary, credit, and exchange authority, i.e., the Board of Banco de la República, but also those who have responsibilities in the formulation and implementation of the general economic policy of the country” and that “the basic constitutional purpose of Banco de la República is the protection of a sound currency. However, this authority must take the other economic objectives of state intervention such as full employment into consideration in their decisions since these functions must be coordinated with the general economic policy.” The reforms to Banco de la República agreed upon in the Constitutional Assembly of 1991 and in Act 31/1992 can be summarized in the following aspects: i) the Bank was assigned a specific mandate: to maintain the purchasing power of the currency in coordination with the general economic policy; ii) the BDBR was designatedas the monetary, foreign exchange, and credit authority; iii) the Bank and its Board of Directors were granted a significant degree of independence from the government; iv) the Bank was prohibited from granting credit to the private sector except in the case of the financial sector; v) established that in order to grant credit to the government, the unanimous vote of its Board of Directors was required except in the case of open market transactions; vi) determined that the legislature may, in no case, order credit quotas in favor of the State or individuals; vii) Congress was appointed, on behalf of society, as the main addressee of the Bank’s reporting exercise; and viii) the responsibility for inspection, surveillance, and control over Banco de la República was delegated to the President of the Republic. The members of the National Constitutional Assembly clearly understood that the benefits of low and stable inflation extend to the whole of society and contribute mto the smooth functioning of the economic system. Among the most important of these is that low inflation promotes the efficient use of productive resources by allowing relative prices to better guide the allocation of resources since this promotes economic growth and increases the welfare of the population. Likewise, low inflation reduces uncertainty about the expected return on investment and future asset prices. This increases the confidence of economic agents, facilitates long-term financing, and stimulates investment. Since the low-income population is unable to protect itself from inflation by diversifying its assets, and a high proportion of its income is concentrated in the purchase of food and other basic goods that are generally the most affected by inflationary shocks, low inflation avoids arbitrary redistribution of income and wealth.2 Moreover, low inflation facilitates wage negotiations, creates a good labor climate, and reduces the volatility of employment levels. Finally, low inflation helps to make the tax system more transparent and equitable by avoiding the distortions that inflation introduces into the value of assets and income that make up the tax base. From the monetary authority’s point of view, one of the most relevant benefits of low inflation is the credibility that economic agents acquire in inflation targeting, which turns it into an effective nominal anchor on price levels. Upon receiving its mandate, and using its autonomy, Banco de la República began to announce specific annual inflation targets as of 1992. Although the proposed inflation targets were not met precisely during this first stage, a downward trend in inflation was achieved that took it from 32.4% in 1990 to 16.7% in 1998. At that time, the exchange rate was kept within a band. This limited the effectiveness of monetary policy, which simultaneously sought to meet an inflation target and an exchange rate target. The Asian crisis spread to emerging economies and significantly affected the Colombian economy. The exchange rate came under strong pressure to depreciate as access to foreign financing was cut off under conditions of a high foreign imbalance. This, together with the lack of exchange rate flexibility, prevented a countercyclical monetary policy and led to a 4.2% contraction in GDP that year. In this context of economic slowdown, annual inflation fell to 9.2% at the end of 1999, thus falling below the 15% target set for that year. This episode fully revealed how costly it could be, in terms of economic activity, to have inflation and exchange rate targets simultaneously. Towards the end of 1999, Banco de la República announced the adoption of a new monetary policy regime called the Inflation Targeting Plan. This regime, known internationally as ‘Inflation Targeting,’ has been gaining increasing acceptance in developed countries, having been adopted in 1991 by New Zealand, Canada, and England, among others, and has achieved significant advances in the management of inflation without incurring costs in terms of economic activity. In Latin America, Brazil and Chile also adopted it in 1999. In the case of Colombia, the last remaining requirement to be fulfilled in order to adopt said policy was exchange rate flexibility. This was realized around September 1999, when the BDBR decided to abandon the exchange-rate bands to allow the exchange rate to be freely determined in the market.Consistent with the constitutional mandate, the fundamental objective of this new policy approach was “the achievement of an inflation target that contributes to maintaining output growth around its potential.”3 This potential capacity was understood as the GDP growth that the economy can obtain if it fully utilizes its productive resources. To meet this objective, monetary policy must of necessity play a countercyclical role in the economy. This is because when economic activity is below its potential and there are idle resources, the monetary authority can reduce the interest rate in the absence of inflationary pressure to stimulate the economy and, when output exceeds its potential capacity, raise it. This policy principle, which is immersed in the models for guiding the monetary policy stance, makes the following two objectives fully compatible in the medium term: meeting the inflation target and achieving a level of economic activity that is consistent with its productive capacity. To achieve this purpose, the inflation targeting system uses the money market interest rate (at which the central bank supplies primary liquidity to commercial banks) as the primary policy instrument. This replaced the quantity of money as an intermediate monetary policy target that Banco de la República, like several other central banks, had used for a long time. In the case of Colombia, the objective of the new monetary policy approach implied, in practical terms, that the recovery of the economy after the 1999 contraction should be achieved while complying with the decreasing inflation targets established by the BDBR. The accomplishment of this purpose was remarkable. In the first half of the first decade of the 2000s, economic activity recovered significantly and reached a growth rate of 6.8% in 2006. Meanwhile, inflation gradually declined in line with inflation targets. That was how the inflation rate went from 9.2% in 1999 to 4.5% in 2006, thus meeting the inflation target established for that year while GDP reached its potential level. After this balance was achieved in 2006, inflation rebounded to 5.7% in 2007, above the 4.0% target for that year due to the fact that the 7.5% GDP growth exceeded the potential capacity of the economy.4 After proving the effectiveness of the inflation targeting system in its first years of operation, this policy regime continued to consolidate as the BDBR and the technical staff gained experience in its management and state-of-the-art economic models were incorporated to diagnose the present and future state of the economy and to assess the persistence of inflation deviations and expectations with respect to the inflation target. Beginning in 2010, the BDBR established the long-term 3.0% annual inflation target, which remains in effect today. Lower inflation has contributed to making the macroeconomic environment more stable, and this has favored sustained economic growth, financial stability, capital market development, and the functioning of payment systems. As a result, reductions in the inflationary risk premia and lower TES and credit interest rates were achieved. At the same time, the duration of public domestic debt increased significantly going from 2.27 years in December 2002 to 5.86 years in December 2022, and financial deepening, measured as the level of the portfolio as a percentage of GDP, went from around 20% in the mid-1990s to values above 45% in recent years in a healthy context for credit institutions.Having been granted autonomy by the Constitution to fulfill the mandate of preserving the purchasing power of the currency, the tangible achievements made by Banco de la República in managing inflation together with the significant benefits derived from the process of bringing inflation to its long-term target, make the BDBR’s current challenge to return inflation to the 3.0% target even more demanding and pressing. As is well known, starting in 2021, and especially in 2022, inflation in Colombia once again became a serious economic problem with high welfare costs. The inflationary phenomenon has not been exclusive to Colombia and many other developed and emerging countries have seen their inflation rates move away from the targets proposed by their central banks.5 The reasons for this phenomenon have been analyzed in recent Reports to Congress, and this new edition delves deeper into the subject with updated information. The solid institutional and technical base that supports the inflation targeting approach under which the monetary policy strategy operates gives the BDBR the necessary elements to face this difficult challenge with confidence. In this regard, the BDBR reiterated its commitment to the 3.0% inflation target in its November 25 communiqué and expects it to be reached by the end of 2024.6 Monetary policy will continue to focus on meeting this objective while ensuring the sustainability of economic activity, as mandated by the Constitution. Analyst surveys done in March showed a significant increase (from 32.3% in January to 48.5% in March) in the percentage of responses placing inflation expectations two years or more ahead in a range between 3.0% and 4.0%. This is a clear indication of the recovery of credibility in the medium-term inflation target and is consistent with the BDBR’s announcement made in November 2022. The moderation of the upward trend in inflation seen in January, and especially in February, will help to reinforce this revision of inflation expectations and will help to meet the proposed targets. After reaching 5.6% at the end of 2021, inflation maintained an upward trend throughout 2022 due to inflationary pressures from both external sources, associated with the aftermath of the pandemic and the consequences of the war in Ukraine, and domestic sources, resulting from: strengthening of local demand; price indexation processes stimulated by the increase in inflation expectations; the impact on food production caused by the mid-2021 strike; and the pass-through of depreciation to prices. The 10% increase in the minimum wage in 2021 and the 16% increase in 2022, both of which exceeded the actual inflation and the increase in productivity, accentuated the indexation processes by establishing a high nominal adjustment benchmark. Thus, total inflation went to 13.1% by the end of 2022. The annual change in food prices, which went from 17.2% to 27.8% between those two years, was the most influential factor in the surge in the Consumer Price Index (CPI). Another segment that contributed significantly to price increases was regulated products, which saw the annual change go from 7.1% in December 2021 to 11.8% by the end of 2022. The measure of core inflation excluding food and regulated items, in turn, went from 2.5% to 9.5% between the end of 2021 and the end of 2022. The substantial increase in core inflation shows that inflationary pressure has spread to most of the items in the household basket, which is characteristic of inflationary processes with generalized price indexation as is the case in Colombia. Monetary policy began to react early to this inflationary pressure. Thus, starting with its September 2021 session, the BDBR began a progressive change in the monetary policy stance moving away from the historical low of a 1.75% policy rate that had intended to stimulate the recovery of the economy. This adjustment process continued without interruption throughout 2022 and into the beginning of 2023 when the monetary policy rate reached 12.75% last January, thus accumulating an increase of 11 percentage points (pp). The public and the markets have been surprised that inflation continued to rise despite significant interest rate increases. However, as the BDBR has explained in its various communiqués, monetary policy works with a lag. Just as in 2022 economic activity recovered to a level above the pre-pandemic level, driven, along with other factors, by the monetary stimulus granted during the pandemic period and subsequent months, so too the effects of the current restrictive monetary policy will gradually take effect. This will allow us to expect the inflation rate to converge to 3.0% by the end of 2024 as is the BDBR’s purpose.Inflation results for January and February of this year showed declining marginal increases (13 bp and 3 bp respectively) compared to the change seen in December (59 bp). This suggests that a turning point in the inflation trend is approaching. In other Latin American countries such as Chile, Brazil, Perú, and Mexico, inflation has peaked and has begun to decline slowly, albeit with some ups and downs. It is to be expected that a similar process will take place in Colombia in the coming months. The expected decline in inflation in 2023 will be due, along with other factors, to lower cost pressure from abroad as a result of the gradual normalization of supply chains, the overcoming of supply shocks caused by the weather, and road blockades in previous years. This will be reflected in lower adjustments in food prices, as has already been seen in the first two months of the year and, of course, the lagged effect of monetary policy. The process of inflation convergence to the target will be gradual and will extend beyond 2023. This process will be facilitated if devaluation pressure is reversed. To this end, it is essential to continue consolidating fiscal sustainability and avoid messages on different public policy fronts that generate uncertainty and distrust. 1 This Report to Congress includes Box 1, which summarizes the trajectory of Banco de la República over the past 100 years. In addition, under the Bank’s auspices, several books that delve into various aspects of the history of this institution have been published in recent years. See, for example: Historia del Banco de la República 1923-2015; Tres banqueros centrales; Junta Directiva del Banco de la República: grandes episodios en 30 años de historia; Banco de la República: 90 años de la banca central en Colombia. 2 This is why lower inflation has been reflected in a reduction of income inequality as measured by the Gini coefficient that went from 58.7 in 1998 to 51.3 in the year prior to the pandemic. 3 See Gómez Javier, Uribe José Darío, Vargas Hernando (2002). “The Implementation of Inflation Targeting in Colombia”. Borradores de Economía, No. 202, March, available at: https://repositorio.banrep.gov.co/handle/20.500.12134/5220 4 See López-Enciso Enrique A.; Vargas-Herrera Hernando and Rodríguez-Niño Norberto (2016). “The inflation targeting strategy in Colombia. An historical view.” Borradores de Economía, No. 952. https://repositorio.banrep.gov.co/handle/20.500.12134/6263 5 According to the IMF, the percentage change in consumer prices between 2021 and 2022 went from 3.1% to 7.3% for advanced economies, and from 5.9% to 9.9% for emerging market and developing economies. 6 https://www.banrep.gov.co/es/noticias/junta-directiva-banco-republica-reitera-meta-inflacion-3