Generalized barriers to entry and economic development

In this paper we are going to analyze the dynamics of barriers to entry at the international level. In our model economic development takes place and continues in the long run due to the emergence of new sectors, which can compensate for the diminishing ability of mature sectors to create employment and growth. Each new sector is created by a pervasive innovation, which creates a new market and into and out of which there are entry and exit of firms. Depending on the inter-temporal coordination of the maturation of older sectors and of the maturation of new ones our model can give rise to development paths with growth rates ranging from high to negative, to fluctuations, to bubbles and to chaos. In the construction of our model we found inspiration in a number of growth models, both endogenous and evolutionary as well as on empirical work on structural change. The model also bears some similarity of style to history friendly models. Its unique feature is that it gives rise to an endogenously variable number of sectors. Unless new sectors are exact substitutes of older ones the model gives rise to growing variety. In fact, the main objective for which the model was initially constructed was to test some propositions implying that variety growth is a necessary requirement for long term economic development. Within our model the ability to create new sectors at the right times is the crucial determinant of the growth potential of an economic system. Thus, inter country differences in the barriers to entry into new sectors can be expected to give rise to different rates of growth and in the end to increasingly skewed world income distribution

DockGame: Cooperative Games for Multimeric Rigid Protein Docking

Protein interactions and assembly formation are fundamental to most biological processes. Predicting the assembly structure from constituent proteins -- referred to as the protein docking task -- is thus a crucial step in protein design applications. Most traditional and deep learning methods for docking have focused mainly on binary docking, following either a search-based, regression-based, or generative modeling paradigm. In this paper, we focus on the less-studied multimeric (i.e., two or more proteins) docking problem. We introduce DockGame, a novel game-theoretic framework for docking -- we view protein docking as a cooperative game between proteins, where the final assembly structure(s) constitute stable equilibria w.r.t. the underlying game potential. Since we do not have access to the true potential, we consider two approaches - i) learning a surrogate game potential guided by physics-based energy functions and computing equilibria by simultaneous gradient updates, and ii) sampling from the Gibbs distribution of the true potential by learning a diffusion generative model over the action spaces (rotations and translations) of all proteins. Empirically, on the Docking Benchmark 5.5 (DB5.5) dataset, DockGame has much faster runtimes than traditional docking methods, can generate multiple plausible assembly structures, and achieves comparable performance to existing binary docking baselines, despite solving the harder task of coordinating multiple protein chains.Comment: Under Revie

Phospho3D: a database of three-dimensional structures of protein phosphorylation sites

Phosphorylation is the most common protein post-translational modification. Phosphorylated residues (serine, threonine and tyrosine) play critical roles in the regulation of many cellular processes. Since the amount of data produced by screening assays is growing continuously, the development of computational tools for collecting and analysing experimental data has become a pivotal task for unravelling the complex network of interactions regulating eukaryotic cell life. Here we present Phospho3D, , a database of 3D structures of phosphorylation sites, which stores information retrieved from the phospho.ELM database and is enriched with structural information and annotations at the residue level. The database also collects the results of a large-scale structural comparison procedure providing clues for the identification of new putative phosphorylation sites

Distributionally Robust Model-based Reinforcement Learning with Large State Spaces

Three major challenges in reinforcement learning are the complex dynamical systems with large state spaces, the costly data acquisition processes, and the deviation of real-world dynamics from the training environment deployment. To overcome these issues, we study distributionally robust Markov decision processes with continuous state spaces under the widely used Kullback-Leibler, chi-square, and total variation uncertainty sets. We propose a model-based approach that utilizes Gaussian Processes and the maximum variance reduction algorithm to efficiently learn multi-output nominal transition dynamics, leveraging access to a generative model (i.e., simulator). We further demonstrate the statistical sample complexity of the proposed method for different uncertainty sets. These complexity bounds are independent of the number of states and extend beyond linear dynamics, ensuring the effectiveness of our approach in identifying near-optimal distributionally-robust policies. The proposed method can be further combined with other model-free distributionally robust reinforcement learning methods to obtain a near-optimal robust policy. Experimental results demonstrate the robustness of our algorithm to distributional shifts and its superior performance in terms of the number of samples needed

Chiral photoelectron angular distributions from ionization of achiral atomic and molecular species

We show that the combination of two achiral components - atomic or molecular target plus a circularly polarized photon - can yield chirally structured photoelectron angular distributions. For photoionization of CO, the angular distribution of carbon K-shell photoelectrons is chiral when the molecular axis is neither perpendicular nor (anti-)parallel to the light propagation axis. In photo-double-ionization of He, the distribution of one electron is chiral, if the other electron is oriented like the molecular axis in the former case and if the electrons are distinguishable by their energy. In both scenarios, the circularly polarized photon defines a plane with a sense of rotation and an additional axis is defined by the CO molecule or one electron. This is sufficient to establish an unambiguous coordinate frame of well-defined handedness. To produce a chirally structured electron angular distribution, such a coordinate frame is necessary, but not sufficient. We show that additional electron-electron interaction or scattering processes are needed to create the chiral angular distribution

A MediaWiki implementation of single-access keys

Design principles, features, and data exchange options of an open source implementation of single access keys for the collaborative MediaWiki platform are presented

Climate Variability-Observations, Reconstructions, and Model Simulations for the Atlantic-European and Alpine Region from 1500-2100 AD

A detailed analysis is undertaken of the Atlantic-European climate using data from 500-year-long proxy-based climate reconstructions, a long climate simulation with perpetual 1990 forcing, as well as two global and one regional climate change scenarios. The observed and simulated interannual variability and teleconnectivity are compared and interpreted in order to improve the understanding of natural climate variability on interannual to decadal time scales for the late Holocene. The focus is set on the Atlantic-European and Alpine regions during the winter and summer seasons, using temperature, precipitation, and 500 hPa geopotential height fields. The climate reconstruction shows pronounced interdecadal variations that appear to "lock” the atmospheric circulation in quasi-steady long-term patterns over multi-decadal periods controlling at least part of the temperature and precipitation variability. Different circulation patterns are persistent over several decades for the period 1500 to 1900. The 500-year-long simulation with perpetual 1990 forcing shows some substantial differences, with a more unsteady teleconnectivity behaviour. Two global scenario simulations indicate a transition towards more stable teleconnectivity for the next 100 years. Time series of reconstructed and simulated temperature and precipitation over the Alpine region show comparatively small changes in interannual variability within the time frame considered, with the exception of the summer season, where a substantial increase in interannual variability is simulated by regional climate model

An online authoring and publishing platform for field guides and identification tools

Various implementation approaches are available for digital field guides and identification tools that are created for the web and mobile devices. The architecture of the “biowikifarm” publishing platform and some technical and social advantages of a document- and author-centric approach based on the MediaWiki open source software over custom-developed, database driven software are presented

Ricostruzione della balista imperiale Romana - un piacevole viaggio fra fantasia, storia, tecnologia e … progettazione.

Nel secondo anno, da quando è stato acceso il “Laboratorio di storia dell’ingegneria meccanica”, si prosegue il cammino iniziato nel Corso precedente, che ha portato alla ricostruzione virtuale della balista descritta da Vitruvio e ci si impegna in una ricostruzione della macchina da lancio dei romani dell’età imperiale. Si è così coinvolti in un piacevole viaggio, a cavallo fra fantasia interpretativa e costruttiva, ricerca storica e realtà tecnologica che, definita la “mission” della macchina, fa comprendere l’essenza del progetto. L’analisi accurata delle immagini presenti sulla colonna Traiana fornisce un terreno di discussione e di elaborazione di varie soluzioni costruttive che vengono esaminate e confrontate scoprendo anche inedite interpretazioni delle scene rappresentate. Il lavoro termina con lo “studio” della macchina, i disegni dei particolari e del complessivo. In attesa di una ri-costruzione reale della macchina se ne esegue una virtuale con tanto di lancio .. simulato