1,721,594 research outputs found
Serial Homology
Full text linkSerial homology, i.e., homology between repetitive structures in the same individual organism, is a debated concept in evolutionary developmental biology. The central question is the evolutionary interpretation of “sameness” in the context of the same body. This essay provides a synthetic analysis of the main issues involved in the debate, connecting conceptual problems with current experimental research. It is argued that a concept of serial homology that is not of the all-or-nothing kind can smooth several theoretical inconsistencies, while being more in line with what we know about evolutionary change and the way we investigate it
The Gamma-limit and the related gradient flow for singular perturbation functionals of Perona-Malik type
No full textWe consider a class of nonconvex functionals of the gradient in one dimension, which we regularize with a second order derivative term. After a proper rescaling, suggested by the associated dynamical problems, we show that the sequence {F-nu} of regularized functionals Gamma-converges, as nu --> 0(+), to a particular class of free-discontinuity functionals F, concentrated on SBV functions with finite energy and having only the jump part in the derivative. We study the singular dynamic associated with F, using the minimizing movements method. We show that the minimizing movement starting from an initial datum with a finite number of discontinuities has jump positions fixed in space and whose number is nonincreasing with time. Moreover, there are a finite number of singular times at which there is a dropping of the number of discontinuities. In the interval between two subsequent singular times, the vector of the survived jumps is determined by the system of ODEs which expresses the L-2-gradient of the Gamma-limit. Furthermore the minimizing movement turns out to be continuous with respect to the initial datum. Some properties of a minimizing movement starting from a function with an in finite number of discontinuities are also derived
Fusco G., Tidoni E. “Fenomenologia dell’illusione di movimento in pazienti con lesione midollare”. AIP 2015 - Rovereto, Italy, 10-12 September 2015
No full textFusco G., Tidoni E. “Fenomenologia dell’illusione di movimento in pazienti con lesione midollare”. AIP 2015 - Rovereto, Italy, 10-12 September 201
Twenty Years of Common Agricultural Policy in Europe: A Bibliometric Analysis
No full textThe last few years have been marked by the increasing attention paid by policymakers to agricultural policies. Within this scenario, the Common Agricultural Policy represents one of the main initiatives developed by the European Commission to enhance the agricultural sector. Academics have actively contributed to the debate through empirical studies in order to evaluate the main strengths and weakness related to the public investments made by the European Commission. However, despite the relevance of the topic, the scientific debate is characterized by a high degree of fragmentation caused by the involvement of academics with different scientific backgrounds. Building on this evidence, this paper aims to contribute to the scientific debate on Common Agricultural Policy through a bibliometric analysis. The findings reveal the existence of three independent and complementary research clusters
Climate Change and Food Security in the Northern and Eastern African Regions: A Panel Data Analysis
No full textThe problem of food insecurity is growing across the world, in particular in developing countries. Due to their economic structure, climate change represents one of the major threats for food security levels in African countries. The object of this work was to assess the impact of climate change on the level of food security in the North and East African countries, using a panel data analysis for the period 2000–2012. Average protein supply and average dietary energy supply adequacy were the two different indicators of food security we identified as most appropriate. Indeed, both indicators can provide information concerning the amount and the nutritional value of food supply. The determinants of food security are expressed as a function of rainfall, temperature, land area under cereal production, size of population and GDP. Findings showed that food security in the Northern and Eastern African countries is adversely affected by climate change. Policy makers need to promote those actions capable of mitigating global warming and reducing its economic impact
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