Alternative monetary constitutions and the quest for price stability

This article reviews the various means through which governments and central banks have sought to guarantee long-run price stability. Finn Kydland and Mark Wynne argue that monetary regimes or standards can all be viewed as more or less successful attempts to overcome the well-known time-consistency problem in monetary policy. The classical gold standard, which prevailed in the late nineteenth and early twentieth centuries, can be interpreted as a monetary policy rule that delivered long-run price stability. The fiat monetary standard adopted by countries following the abandonment of gold allows greater discretion on the part of monetary policymakers and has been characterized by greater long-run price instability. Countries have tried through a variety of means to regain the benefits of price stability that prevailed under the earlier gold standard by limiting the scope for discretionary actions on the part of central bankers. A close analogy exists between the gold standard and the currency board arrangements proposed for many emerging market economies in recent years.Money

Ireland's great depression

We argue that Ireland experienced a great depression in the 1980s comparable in severity to the better known and more studied depression episodes of the interwar period. Using the business cycle accounting framework of Chari, Kehoe and McGrattan (2005), we examine the factors that lead to the depression and the subsequent recovery in the 1990s. We calculate efficiency, labor, investment and government wedges, and evaluate the contribution of each to the downturn and subsequent recovery. We find that the efficiency wedge on its own can account for a significant portion of the downturn, but predicts a stronger recovery in output. The labor wedge also helps account for what happened during the depression episode. We also find that the investment wedge played no role in the depression.

Dynamic mimicry in an Indo-Malayan octopus

During research dives in Indonesia (Sulawesi and Bali), we filmed a distinctive long-armed octopus, which is new to science. Diving over 24 h periods revealed that the 'mimic octopus' emerges during daylight hours to forage on sand substrates in full view of pelagic fish predators. We observed nine individuals of this species displaying a repertoire of postures and body patterns, several of which are clearly impersonations of venomous animals co-occurring in this habitat. This 'dynamic mimicry' avoids the genetic constraints that may limit the diversity of genetically polymorphic mimics but has the same effect of decreasing the frequency with which predators encounter particular mimics. Additionally, our observations suggest that the octopus makes decisions about the most appropriate form of mimicry to use, allowing it to enhance further the benefits of mimicking toxic models by employing mimicry according to the nature of perceived threats

Female impersonation as an alternative reproductive strategy in giant cuttlefish

Out of all the animals, cephalopods possess an unrivalled ability to change their shape and body patterns. Our observations of giant cuttlefish (Sepia apama) suggest this ability has allowed them to evolve alternative mating strategies in which males can switch between the appearance of a female and that of a male in order to foil the guarding attempts of larger males. At a mass breeding aggregation in South Australia, we repeatedly observed single small males accompanying mating pairs. While doing so, the small male assumed the body shape and patterns of a female. Such males were never attacked by the larger mate-guarding male. On more than 20 occasions, when the larger male was distracted by another male intruder, these small males, previously indistinguishable from a female, were observed to change body pattern and behaviour to that of a male in mating display. These small males then attempted to mate with the female, often with success. This potential for dynamic sexual mimicry may have played a part in driving the evolution of the remarkable powers of colour and shape transformation which characterize the cephalopods

Approximation of bayesian Hawkes process models with Inlabru

Hawkes process are very popular mathematical tools for modelling phenomena exhibiting a \textit{self-exciting} or \textit{self-correcting} behaviour. Typical examples are earthquakes occurrence, wild-fires, drought, capture-recapture, crime violence, trade exchange, and social network activity. The widespread use of Hawkes process in different fields calls for fast, reproducible, reliable, easy-to-code techniques to implement such models. We offer a technique to perform approximate Bayesian inference of Hawkes process parameters based on the use of the R-package \inlabru. The \inlabru R-package, in turn, relies on the INLA methodology to approximate the posterior of the parameters. Our Hawkes process approximation is based on a decomposition of the log-likelihood in three parts, which are linearly approximated separately. The linear approximation is performed with respect to the mode of the parameters' posterior distribution, which is determined with an iterative gradient-based method. The approximation of the posterior parameters is therefore deterministic, ensuring full reproducibility of the results. The proposed technique only requires the user to provide the functions to calculate the different parts of the decomposed likelihood, which are internally linearly approximated by the R-package \inlabru. We provide a comparison with the \bayesianETAS R-package which is based on an MCMC method. The two techniques provide similar results but our approach requires two to ten times less computational time to converge, depending on the amount of data.Comment: 2o pages, 7 figures, 5 table

Learning to Interactively Learn and Assist

When deploying autonomous agents in the real world, we need effective ways of communicating objectives to them. Traditional skill learning has revolved around reinforcement and imitation learning, each with rigid constraints on the format of information exchanged between the human and the agent. While scalar rewards carry little information, demonstrations require significant effort to provide and may carry more information than is necessary. Furthermore, rewards and demonstrations are often defined and collected before training begins, when the human is most uncertain about what information would help the agent. In contrast, when humans communicate objectives with each other, they make use of a large vocabulary of informative behaviors, including non-verbal communication, and often communicate throughout learning, responding to observed behavior. In this way, humans communicate intent with minimal effort. In this paper, we propose such interactive learning as an alternative to reward or demonstration-driven learning. To accomplish this, we introduce a multi-agent training framework that enables an agent to learn from another agent who knows the current task. Through a series of experiments, we demonstrate the emergence of a variety of interactive learning behaviors, including information-sharing, information-seeking, and question-answering. Most importantly, we find that our approach produces an agent that is capable of learning interactively from a human user, without a set of explicit demonstrations or a reward function, and achieving significantly better performance cooperatively with a human than a human performing the task alone.Comment: AAAI 2020. Video overview at https://youtu.be/8yBvDBuAPrw, paper website with videos and interactive game at http://interactive-learning.github.io

Protein Refinery Operations Lab (PRO Lab): A sandbox for continuous protein production & advanced process control

Significant strides towards implementation of continuous bioprocessing are being made at an ever increasing rate. Advances in technology for traditional unit operations such as cell-retention devices in perfusion cell culture, continuous multi-column chromatography (CMCC) and single-pass tangential flow filtration have led to demonstrations of both semi-continuous and fully-continuous protein production processes operating at periodic steady states at the pilot-scale. Previous proof of concept work at Merck & Co., Inc. has shown an automated (DeltaV) and single-use monoclonal antibody (mAb) purification scheme through Protein A CMCC and pH viral inactivation with minimal human interaction for 30 days fed from a perfusion bioreactor1. This automation scheme has since been expanded to encompass an integrated mAb upstream and platform downstream process, resulting in an entirely automated ‘protein refinery’ sandbox. In this presentation a vision for a continuous bioprocessing facility of the future will be presented wherein the integration of Process Analytical Technologies (PAT), Multivariate Data Analysis, (MVDA), and feedback control strategies will lead to more streamlined plant operations and high product quality consistency. A discussion of how the control strategies put into place in PRO Lab lays the groundwork for this vision and how PRO Lab will be used to pilot PAT, MVDA, and feedback control as they become mature enough for integration into the continuous platform will be provided. These tools, working together, and validated in the sandbox environment, will ultimately enable real-time-release of drug substance. PRO Lab will also enable better holistic process understanding by enabling perturbation analysis and propagation throughout the production line. Process and product quality consistency data through a period of \u3e30days will be presented from PRO Lab as an initial step towards toward the ultimate vision of an automated well-controlled, well characterized protein refinery

The eyes have it?-intra- and inter-observer reproducibility of the PD-L1 companion diagnostic assay

No abstract available