1,354,801 research outputs found
A survey on abelian dynamical Galois groups
Full text linkLet be a number field, and . A recent conjecture
of Andrews and Petsche predicts that the dynamical Galois group of the pair
is abelian if and only if the pair is
-conjugated to , where is a power or a Chebyshev
map and is or , respectively, and is
a root of unity. We review three completely different approaches that allow to
prove several cases of the conjecture.Comment: Rendiconti Sem. Mat. Univ. Pol. Torino Vol. 80, 2022 (2022), 41 - 5
Cyclotomic and abelian points in backward orbits of rational functions
No full textWe prove several results on backward orbits of rational functions over number
fields. First, we show that if is a number field, and
then the extension of generated by the abelian points in the
backward orbit of is ramified only at finitely many primes. This has
the immediate strong consequence that if all points in the backward orbit of
are abelian then is post-critically finite. We use this result
to prove two facts: on the one hand, if is a quadratic
rational function not conjugate over to a power or a
Chebyshev map and all preimages of are abelian, we show that is
-conjugate to one of two specific quadratic functions, in the spirit
of a recent conjecture of Andrews and Petsche. On the other hand we provide
conditions on a quadratic rational function in for the backward orbit of
a point to only contain finitely many cyclotomic preimages, extending
previous results of the second author. Finally, we give necessary and
sufficient conditions for a triple , where is a
Latt\`es map over a number field and for the whole backward
orbit of to only contain abelian points
Francesco Buranelli et Ugo Ferraguti, L'ultimo archeologo-mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti.
No full textBouloumié Bernard. Francesco Buranelli et Ugo Ferraguti, L'ultimo archeologo-mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti. . In: L'antiquité classique, Tome 65, 1996. pp. 592-593
Buranelli (Francesco), Ugo Ferraguti, L'ultimo archeologo mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti. (Archeologia ; 109) 1994
No full textJannot Jean-René. Buranelli (Francesco), Ugo Ferraguti, L'ultimo archeologo mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti. (Archeologia ; 109) 1994. In: Revue des Études Anciennes. Tome 98, 1996, n°3-4. p. 458
On a Conjecture on Irreducible Polynomials over Finite Fields with Restricted Coefficients
No full textThe set of stable primes for polynomial sequences with large Galois group
Full text linkLet K be a number field with ring of integers OK, and let {fk}k∈N be a sequence of monic polynomials in OK[x] such that for every n ∈ N, the composition f(n) = f1 ◦ f2 ◦ ... ◦ fn is irreducible. In this paper we show that if the size of the Galois group of f(n) is large enough (in a precise sense) as a function of n, then the set of primes p ⊆ OK such that every f(n) is irreducible modulo p has density zero. Moreover, we prove that the subset of polynomial sequences such that the Galois group of f(n) is large enough has density 1, in an appropriate sense, within the set of all polynomial sequences
Buranelli (Francesco), Ugo Ferraguti, L'ultimo archeologo mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti. (Archeologia ; 109) 1994
No full textJannot Jean-René. Buranelli (Francesco), Ugo Ferraguti, L'ultimo archeologo mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti. (Archeologia ; 109) 1994. In: Revue des Études Anciennes. Tome 98, 1996, n°3-4. p. 458
Buranelli (Francesco). Ugo Ferraguti, l 'ultimo archeologo-mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti.
No full textFontaine Paul. Buranelli (Francesco). Ugo Ferraguti, l 'ultimo archeologo-mecenate. Cinque anni di scavi a Vulci (1928-1932) attraverso il fondo fotografico Ugo Ferraguti.. In: Revue belge de philologie et d'histoire, tome 74, fasc. 1, 1996. Antiquité - Oudheid. pp. 238-239
Functional expression of the GABA A receptor α2 and α3 subunits at synapses between intercalated medial paracapsular neurons of mouse amygdala
Full text linkIn the amygdala, GABAergic neurons in the intercalated medial paracapsular cluster (Imp) have been suggested to play a key role in fear learning and extinction. These neurons project to the central (CE) amygdaloid nucleus and to other areas within and outside the amygdala. In addition, they give rise to local collaterals that innervate other neurons in the Imp. Several drugs, including benzodiazepines (BZ), are allosteric modulators of GABA A receptors. BZ has both anxiolytic and sedative actions, which are mediated through GABA A receptors containing α2/α3 and α1 subunits, respectively. To establish whether α1 or α2/α3 subunits are expressed at Imp cell synapses, we used paired recordings of anatomically identified Imp neurons and high resolution immunocytochemistry in the mouse. We observed that a selective α3 subunit agonist, TP003 (100 nM), significantly increased the decay time constant of the unitary IPSCs. A similar effect was also induced by zolpidem (10 μM) or by diazepam (1 μM). In contrast, lower doses of zolpidem (0.1-1 μM) did not significantly alter the kinetics of the unitary IPSCs. Accordingly, immunocytochemical experiments established that the α2 and α3, but not the α1 subunits of the GABA A receptors, were present at Imp cell synapses of the mouse amygdala. These results define, for the first time, some of the functional GABA A receptor subunits expressed at synapses of Imp cells. The data also provide an additional rationale to prompt the search of GABA A receptor α3 selective ligands as improved anxiolytic drugs. © 2012 Geracitano, Fischer, Kasugai, Ferraguti and Capogna
The phylogeny of Branchiobdellida (Annelida, Clitellata) assessed by sperm characters
No full textData on the spermatozoa of Branchiobdellida were taken from the published literature: sperm models of 25 species belonging to 13 different branchiobdellidan genera have been compared with the aim of supplying further evidences for a phylogenetic analysis of the group. The species considered were representative of all traditional branchiobdellidan families, excluding the monotypic Caridinophilidae. Branchiobdellidan spermatozoa are complex cells, thus it was possible to analyse the variation of 20 characters within the group. A parsimony analysis has yielded nine minimal trees, eight of which are very similar to one another. The main conclusions of the phylogenetic analysis are: (a) the monophyly of the taxon Branchiobdellida is confirmed; (b) the most speciose branchiobdellidan genus, Cambarincola is polyphyletic; (c) none of the traditional 'families' are supported; (d) the genus Branchiobdella is monophyletic, but the position of one species, B. kobayashi, albeit basal to the whole genus, is not resolved; (e) the other two genera analysed for which more than one species was available, Pterodrilus and Xironogiton, are monophyletic; (f) there seems to be a 'trend' in the whole group towards an increase of acrosome length. Our results partly parallel those obtained by Gelder and Siddall (2000) with a combined analysis of molecular and somatic characters, and point to the need for a comprehensive revision of the Branchiobdellida based on a combination of molecular, somatic and spermatological data sets. (C) 2004 Elsevier GmbH. All rights reserved
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