Search results for "Structural change"
showing 10 items of 44 documents
Observations on midgut of Apis mellifera workers (Hymenoptera: Apoidea) under controlled acute exposures to a Bacillus thuringiensis-based biopestici…
2016
International audience; AbstractMorphostructural investigations have been carried out on Apis mellifera workers treated with single controlled acute exposures to a biopesticide containing Bacillus thuringiensis (Bt), to detect midgut changes until 96 h. Our findings show concentration-dependence of these changes, reflecting in different degrees on both mortality and behaviour. In particular, some midgut changes are also found 96 h after treatment. Our results show that the tested product does not affect survival at presumable environmental concentrations, so confirming the lesser toxicity of Bt-based biopesticides compared to other pesticides. However, in the light of the discovered long-te…
Light-induced structural changes in a monomeric bacteriophytochrome
2016
International audience; Phytochromes sense red light in plants and various microorganism. Light absorption causes structural changes within the protein, which alter its biochemical activity. Bacterial phytochromes are dimeric proteins, but the functional relevance of this arrangement remains unclear. Here, we use time-resolved X-ray scattering to reveal the solution structural change of a monomeric variant of the photosensory core module of the phytochrome from Deinococcus radiodurans. The data reveal two motions, a bend and a twist of the PHY domain with respect to the chromophore-binding domains. Infrared spectroscopy shows the refolding of the PHY tongue. We conclude that a monomer of th…
Coupling between criticality and gelation in "sticky" spheres: a structural analysis.
2018
We combine experiments and simulations to study the link between criticality and gelation in sticky spheres. We employ confocal microscopy to image colloid-polymer mixtures and Monte Carlo simulations of the square-well (SW) potential as a reference model. To this end, we map our experimental samples onto the SW model. We find an excellent structural agreement between experiments and simulations, both for locally favored structures at the single particle level and large-scale fluctuations at criticality. We follow in detail the rapid structural change in the critical fluid when approaching the gas-liquid binodal and highlight the role of critical density fluctuations for this structural cro…
Bicausative matrices to measure structural change: Are they a good tool?
1999
The causative-matrix method to analyze temporal change assumes that a matrix transforms one Markovian transition matrix into another by a left multiplication of the first matrix; the method is demand-driven when applied to input-output economics. An extension is presented without assuming the demand-driven or supply-driven hypothesis. Starting from two flow matrices X and Y, two diagonal matrices are searched, one premultiplying and the second postmultiplying X, to obtain a result the closer as possible to Y by least squares. The paper proves that the method is deceptive because the diagonal matrices are unidentified and the interpretation of results is unclear. Keywords : Input-Output ; Ch…
Structural change in a Ricardian world economy: The role of extensive rent
2019
Abstract We study an implication of the Ricardian theory of differential extensive rent in a free trade regime. To this effect we develop a Ricardian two country two commodity open economy model. We assume that, unlike labour, land is heterogeneous both within and across countries and that the ratio of high to low quality land is different among the trading countries. By means of a numerical example we show that as the process of worldwide capital accumulation (and population growth) proceeds an industrial country may find it convenient to increase its domestic corn production and even reverse completely the pattern of its imports and exports.
Glucagon fibril polymorphism reflects differences in protofilament backbone structure
2010
Amyloid fibrils formed by the 29-residue peptide hormone glucagon at different concentrations have strikingly different morphologies when observed by transmission electron microscopy. Fibrils formed at low concentration (0.25 mg/mL) consist of two or more protofilaments with a regular twist, while fibrils at high concentration (8 mg/mL) consist of two straight protofilaments. Here, we explore the structural differences underlying glucagon polymorphism using proteolytic degradation, linear and circular dichroism, Fourier transform infrared spectroscopy (FTIR), and X-ray fiber diffraction. Morphological differences are perpetuated at all structural levels, indicating that the two fibril class…
High-pressure X-ray diffraction study of EuWO4 to 12 GPa
2005
In-situ high-pressure X-ray diffraction studies were performed on EuWO4 to 12 GPa. We found that EuWO4 transforms from the tetragonal I41/a structure to the monoclinic I2/a structure at 8.5(5) GPa, being this phase transition re- versible. No other structural change is detected up to 12 GPa. The EOS of EuWO4 is determined from the pressure–volume data. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear economic growth: Some theory and cross-country evidence
2007
Abstract This paper aims to test the existence of different growth regimes, that is of different relationships between growth rate and income level. We propose a simple nonlinear growth model and test its empirical implications by estimating Markov transition matrices and stochastic kernels. We show that growth is indeed nonlinear: a first phase of slow or zero growth is followed by a take-off and, finally, by a phase of deceleration. We discuss the relevance of these results with respect to the issue of convergence and reversibility of development, in the light of models of structural change and technological diffusion.
Investment–productivity dynamics and distribution dynamics in a multisector economy: some theory and an application to Italian regions
2003
Abstract In this paper, we study the investment–productivity dynamics in the Framework Space, presented by Bohm and Punzo [Cycles, Growth and Structural Change, Routledge, London (2001) 47], as the distribution dynamics of the production sectors of an economy. We apply such theoretical framework to data from Italian regions to identify differences in sectoral behaviors both within and across regions. Our main findings are: sectors within a region generally follow different regime dynamics; Southern Italian regions are generally characterized by higher degrees of heterogeneity in sectoral growth behaviors and of regime instability. Also, we find support to the hypothesis of a positive relati…
Structural Change in Finnish Manufacturing: The Theory of the Aggregation of Production Functions and an Empirical Analysis with a Plant-Level Panel
2011
Abstract In this paper, structural change in the Finnish manufacturing industries is studied using the theory of the aggregation of production functions and longitudinal plant-level data for the period from 1980 to 2005. To characterise the nature of structural change in 12 industries, we examine the invariance of aggregate production functions over time. Aggregate production functions need not be estimated because, according to the theory of the aggregation of production functions, the invariance can be analysed by investigating the stability of capacity density functions, which describe the distribution of value added in these industries. Even though the shapes of aggregate production fun…