588 research outputs found
Labour productivity in the Nordic EU countries - a comparative overview and explanatory factors â 1998-2004
This paper analyses the differences in hourly labour productivity growth rates and levels between the Nordic EU countries (Denmark, Finland and Sweden) and four larger euro area countries (Germany, France, Italy and Spain). Additional information for the euro area as a whole, the UK and the US is also provided. Given that the economic and social models developed in the Nordic EU countries are in many ways closer to those of the larger euro area countries than that of the US, the experience of these countries is particularly interesting. Since the mid-1990s, the Nordic EU countries, particularly Sweden and Finland, have experienced stronger labour productivity growth than the larger euro countries. Like in the US, innovation and technological changes have played a major role in explaining the higher labour productivity growth in the Nordic EU countries compared with the larger euro area economies. Information and Communication Technology (ICT) diffusion is a key element to explain these differences. A number of institutional indicators, relating to market regulation, human capital, R&D investments and venture capital, show that the Nordic EU economies are better positioned than some of the larger euro area countries to exploit the opportunities provided by ICT in terms of productivity growth. However, remaining labour market rigidities may not allow the Nordic EU countries to fully enjoy the benefits of ICT diffusion in terms of increased employment.
Two-Level Type Theory and Applications
We define and develop two-level type theory (2LTT), a version of Martin-L\"of
type theory which combines two different type theories. We refer to them as the
inner and the outer type theory. In our case of interest, the inner theory is
homotopy type theory (HoTT) which may include univalent universes and higher
inductive types. The outer theory is a traditional form of type theory
validating uniqueness of identity proofs (UIP). One point of view on it is as
internalised meta-theory of the inner type theory.
There are two motivations for 2LTT. Firstly, there are certain results about
HoTT which are of meta-theoretic nature, such as the statement that
semisimplicial types up to level can be constructed in HoTT for any
externally fixed natural number . Such results cannot be expressed in HoTT
itself, but they can be formalised and proved in 2LTT, where will be a
variable in the outer theory. This point of view is inspired by observations
about conservativity of presheaf models.
Secondly, 2LTT is a framework which is suitable for formulating additional
axioms that one might want to add to HoTT. This idea is heavily inspired by
Voevodsky's Homotopy Type System (HTS), which constitutes one specific instance
of a 2LTT. HTS has an axiom ensuring that the type of natural numbers behaves
like the external natural numbers, which allows the construction of a universe
of semisimplicial types. In 2LTT, this axiom can be stated simply be asking the
inner and outer natural numbers to be isomorphic.
After defining 2LTT, we set up a collection of tools with the goal of making
2LTT a convenient language for future developments. As a first such
application, we develop the theory of Reedy fibrant diagrams in the style of
Shulman. Continuing this line of thought, we suggest a definition of
(infinity,1)-category and give some examples.Comment: 53 page
Adventures in Formalisation: Financial Contracts, Modules, and Two-Level Type Theory
We present three projects concerned with applications of proof assistants in
the area of programming language theory and mathematics. The first project is
about a certified compilation technique for a domain-specific programming
language for financial contracts (the CL language). The code in CL is
translated into a simple expression language well-suited for integration with
software components implementing Monte Carlo simulation techniques (pricing
engines). The compilation procedure is accompanied with formal proofs of
correctness carried out in Coq. The second project presents techniques that
allow for formal reasoning with nested and mutually inductive structures built
up from finite maps and sets. The techniques, which build on the theory of
nominal sets combined with the ability to work with isomorphic representations
of finite maps, make it possible to give a formal treatment, in Coq, of a
higher-order module system, including the ability to eliminate at compile time
abstraction barriers introduced by the module system. The development is based
on earlier work on static interpretation of modules and provides the foundation
for a higher-order module language for Futhark, an optimising compiler
targeting data-parallel architectures. The third project presents an
implementation of two-level type theory, a version of Martin-Lof type theory
with two equality types: the first acts as the usual equality of homotopy type
theory, while the second allows us to reason about strict equality. In this
system, we can formalise results of partially meta-theoretic nature. We develop
and explore in details how two-level type theory can be implemented in a proof
assistant, providing a prototype implementation in the proof assistant Lean. We
demonstrate an application of two-level type theory by developing some results
on the theory of inverse diagrams using our Lean implementation.Comment: PhD thesis defended in January 2018 at University of Copenhagen,
Department of Computer Scienc
Definition of a family of tissue-protective cytokines using functional cluster analysis: a proof-of-concept study
The discovery of the tissue-protective activities of erythropoietin (EPO) has underlined the importance of some cytokines in tissue-protection, repair, and remodeling. As such activities have been reported for other cytokines, we asked whether we could define a class of tissue-protective cytokines. We therefore explored a novel approach based on functional clustering. In this pilot study, we started by analyzing a small number of cytokines (30). We functionally classified the 30 cytokines according to their interactions by using the bioinformatics tool STRING (Search Tool for the Retrieval of Interacting Genes), followed by hierarchical cluster analysis. The results of this functional clustering were different from those obtained by clustering cytokines simply according to their sequence. We previously reported that the protective activity of EPO in a model of cerebral ischemia was paralleled by an upregulation of synaptic plasticity genes, particularly early growth response 2 (EGR2). To assess the predictivity of functional clustering, we tested some of the cytokines clustering close to EPO (interleukin-11, IL-11; kit ligand, KITLG; leukemia inhibitory factor, LIF; thrombopoietin, THPO) in an in vitro model of human neuronal cells for their ability to induce EGR2. Two of these, LIF and IL-11, induced EGR2 expression. Although these data would need to be extended to a larger number of cytokines and the biological validation should be done using more robust in vivo models, rather then just one cell line, this study shows the feasibility of this approach. This type of functional cluster analysis could be extended to other fields of cytokine research and help design biological experiments
Peinture et rĂ©volution : propos de LĂ©nine et de Trotsky sur lâart pictural dâaprĂšs les souvenirs dâun portraitiste officiel
Une brĂšve prĂ©sentation des Vies et Ćuvres (au pluriel) dâIouri Pavlovitch (dit Georges) Annenkov (1889-1974) constitue simplement un dĂ©fi au bon sens : lâhomme a en effet touchĂ© Ă tout, Ă la fois portraitiste, peintre, lithographe, illustrateur, dĂ©corateur de thĂ©Ăątre, costumier de cinĂ©ma, caricaturiste, Ă©crivain, critique, metteur en scĂšne... Il a Ă©tĂ© lâami de nombreuses cĂ©lĂ©britĂ©s â russes, françaises, italiennes â, lâadmirateur de nombreuses cultures â russe, japonaise, finlandaise et mĂ©dit..
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