102,156 research outputs found
Continued fractions with SL(2,Z)-branches: combinatorics and entropy
No full textWe study the dynamics of a family Kα of discontinuous interval maps whose (infinitely many) branches are Mo ̈bius transformations in SL(2, Z) and which arise as the critical-line case of the family of (a, b)-continued frac- tions.
We provide an explicit construction of the bifurcation locus EKU for this family, showing it is parametrized by Farey words and it has Hausdorff di- mension zero. As a consequence, we prove that the metric entropy of Kα is analytic outside the bifurcation set but not differentiable at points of EKU and that the entropy is monotone as a function of the parameter.
Finally, we prove that the bifurcation set is combinatorially isomorphic to the main cardioid in the Mandelbrot set, providing one more entry to the dictionary developed by the authors between continued fractions and complex dynamics
A canonical thickening of Q and the dynamics of continued fractions
No full textWe construct a countable family of open intervals contained in (0,1] whose endpoints are quadratic surds and such that their union is a full measure set. We then show that these intervals are precisely the monotonicity intervals of the entropy of α-continued fractions, thus proving a conjecture of Nakada and Natsui
Discovery of male-sterility in leaf chicory opens new frontiers for breeding heterotic F1 hybrid varieties
No full textDialettologia in Veneto. Indici degli atti dei Convegni internazionali di studi di Sappada/Plodn (Belluno), 1995-2007.
No full textFertimetro, a Principle and Device to Measure Soil Nutrient Availability for Plants by Microbial Degradation Rates on Differently-Spiked Buried Threads
No full textA novel patented method (PCT/IB2012/001157: Squartini, Concheri, Tiozzo, University of Padova) and the corresponding application devices, suitable to measure soil fertility, are presented. The availability or deficiency of specific nutrients for crops is assessed by monitoring the kinetics of progressive weakening of cotton or silk threads due to in situ microbial activity. The method is based on a nutrient-primed incremented substrate degradation principle. Threads are buried as is or pre-impregnated with N or P solutions, and the acceleration of the degradation rate for the N-supplemented or P-supplemented thread, in comparison to the untreated thread, is proportional to the lack of the corresponding nutrient in that soil. Tests were validated on corn crops in plots receiving increasing fertilizer rates in a historical rotation that has been established since 1962. The measurement carried out in May significantly correlated with the subsequent crop yields recorded in October. The analysis allows an early, inexpensive, fast, and reproducible self-assessment at field level to improve fertilization rates. The device is envisaged as a user-friendly tool for agronomy, horticulture, and any environmental applications where organic matter cycling, soil quality, and specific nutrients excess or deficiency are critical considerations
Discovery of nuclear male-sterility in red chicory: genetic analysis and methods for the marker-assisted breeding of F1 hybrid varieties
No full textDynamics of continued fractions and kneading sequences of unimodal maps
No full textIn this paper we construct a correspondence between the parameter spaces of two families of one-dimensional dynamical systems, the α-continued fraction transformations Tα and unimodal maps. This correspondence identifies bifurcation parameters in the two families, and allows one to transfer topological and metric properties from one setting to the other. As an application, we recover results about the real slice of the Mandelbrot set, and the set of univoque numbers
Clusterin (SGP-2) gene expression is cell cycle dependent in normal human dermal fibroblasts
No full textIn confluent human dermal fibroblasts brought to quiescence (G(0)) by serum starvation, the S phase peaked at 24 h after serum re-addiction and G(2)/M phase peaked at 36 h. This was confirmed by titration of h-gas1 mRNA (a marker of G(0) phase) and histone H3 (a marker of S phase). Clusterin mRNA accumulation progressively increased in cells proceeding to confluence after seeding and to quiescence upon serum starvation, and peaked at around G(0), in parallel with h-gas1 mRNA. At 6 h (roughly G(1) phase) clusterin transcript formed a second peak, followed by a gradual decrease until 36 h. Correspondence of clusterin protein accumulation to its mRNA occurred solely with regard to the G(0) peak but not to the second one. The possible meaning of the cell cycle related clusterin gene expression is discussed. (C) 1999 Federation of European Biochemical Societies
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