Search results for "BW"

Sturmian graphs and integer representations over numeration systems

2012

AbstractIn this paper we consider a numeration system, originally due to Ostrowski, based on the continued fraction expansion of a real number α. We prove that this system has deep connections with the Sturmian graph associated with α. We provide several properties of the representations of the natural integers in this system. In particular, we prove that the set of lazy representations of the natural integers in this numeration system is regular if and only if the continued fraction expansion of α is eventually periodic. The main result of the paper is that for any number i the unique path weighted i in the Sturmian graph associated with α represents the lazy representation of i in the Ost…

Diode-pumped self-Q-switched erbium-doped all-fibre laser

2004

A diode-pumped self-Q-switched erbium-doped fibre laser is developed and studied. The laser has an all-fibre configuration containing a piece of an active heavily erbium-doped fibre and two fibre Bragg grating mirrors and does not require any additional intracavity elements to obtain short pulses. Analysis of the laser operation suggests that the most probable mechanism of passive Q-switching of the laser cavity is absorption from the excited state of erbium resulting in the thermally induced nonlinear change in the refractive index in the erbium-doped fibre.

FOLLOW-UP 2003-2008 DEI NATI VERY LOW BIRTH WEIGHT: ESITI NEUROLOGICI

2009

Sorting suffixes of a text via its Lyndon Factorization

2013

The process of sorting the suffixes of a text plays a fundamental role in Text Algorithms. They are used for instance in the constructions of the Burrows-Wheeler transform and the suffix array, widely used in several fields of Computer Science. For this reason, several recent researches have been devoted to finding new strategies to obtain effective methods for such a sorting. In this paper we introduce a new methodology in which an important role is played by the Lyndon factorization, so that the local suffixes inside factors detected by this factorization keep their mutual order when extended to the suffixes of the whole word. This property suggests a versatile technique that easily can b…

Properties of a Class of Toeplitz Words

2021

We study the properties of the uncountable set of Stewart words. These are Toeplitz words specified by infinite sequences of Toeplitz patterns of the form $\alpha\beta\gamma$, where $\alpha,\beta,\gamma$ is any permutation of the symbols 0,1,?. We determine the critical exponent of the Stewart words, prove that they avoid the pattern $xxyyxx$, find all factors that are palindromes, and determine their subword complexity. An interesting aspect of our work is that we use automata-theoretic methods and a decision procedure for automata to carry out the proofs.

Transmissibility of Broad bean wilt virus 1 by aphids: influence of virus accumulation in plants, virus genotype and aphid species

2013

Broad bean wilt virus 1 (BBWV-1) is transmitted by several aphid species in a non-persistent manner. Transmission efficiency by vectors is a key factor for understanding virus epidemiology and applying disease control measures based on limiting virus spread. We evaluated the transmission rates of two genetically divergent BBWV-1 isolates (PV-132 from USA and Ben from Spain) infecting broad bean (Vicia faba L.) by isofemale lines of nine aphid species from eight different genera collected in Spain. Our analyses showed that: (a) the virus concentration in the source plant was a key factor in BBWV-1 transmissibility; (b) The Spanish isolate Ben was transmitted more efficiently than the America…

Fabrication of polarizing photonic crystal fibres and photonic crystal fibre tapers: Applications

2007

We report the fabrication of an anisotropic photonic crystal fibre with polarization properties and photonic crystal fibre tapers for supercontinuum generation. The anisotropy of the fibre was created by enlarging four airholes next to the silica core. Different polarization regimes as a function of the geometric parameters, including polarizing behaviour at 1.55 mum, were obtained. In the second part of the paper, we report the fabrication of photonic crystal fibre tapers. We present experimental results on supercontinuum generation in photonic crystal fibre tapers using quasi-continuous pump pulses of 7 ns duration at 532 nm and at 1064 nm.

Gene Regulation and Species-Specific Evolution of Free Flight Odor Tracking in Drosophila

2018

Running title: flight evolution in Drosophila This is an invited contribution to the special issue on Genetics of Adaptation based on a symposium of the same name at the National Centre for Biological Sciences (TIFR, Bangalore, India) in November 2016; International audience; The flying ability of insects has coevolved with the development of organs necessary to take-off from the ground, generate, and modulate lift during flight in complex environments. Flight orientation to the appropriate food source and mating partner depends on the perception and integration of multiple chemical signals. We used a wind tunnel-based assay to investigate the natural and molecular evolution of free flight …

First country records for two species of the Afrotropical genus Coridiellus J.A. Lis, 1990 (Hemiptera: Heteroptera: Dinidoridae)

2018

First country records are provided for two species of the Afrotropical genus Coridiellus J.A. Lis, 1990, i.e. C. bechynei (Villiers, 1956) [Democratic Republic of the Congo, Zimbabwe] and C. lenoiri (Schouteden, 1909) [Zambia]. Their parameres are illustrated for the first time.

Two new African and Madagascan species of the genus Holochlora (Orthoptera: Tettigoniidae, Phaneropterinae)

2017

Two new species, Holochlora mauritiana and H. ingrischi from the island of Mauritius and Zimbabwe, respectively, are described. Along with a third species, H. biloba Stål, 1874 from Madagascar, they are the sole African representatives of the mostly Oriental genus Holochlora Stål, 1873, including ca. 60 taxa distributed from India to China. Preliminary hypotheses on biogeographical and evolutionary origin of Afro-Madagascan Holochlora species are shortly discussed.