Search results for "alternation"
showing 10 items of 26 documents
A quantitative survey of N Prep N constructions in Romance languages and prepositional variability
2018
The distinction between syntagmatic compounds of the type N Prep N, such as Fr. jouet d’enfant, and nominal syntagms of the type N Prep N, such as the partially equivalent Fr. jouet pour enfants, remains unclear and vague. This is mainly because the lexical and syntactic status of syntagmatic compounds still is controversial. In some cases, as in jouet d’enfant and jouet pour enfants, partial equivalent syntagmatic compounds and nominal syntagms may coexist and underlie a specific variation and alternation. In other cases, such as Pt. bracelete de aço and bracelete em aço, two variants of a syntagmatic compound may alternate and coexist. The first part of this paper provides an overview of …
Modulation of hippocampal theta oscillations and spatial memory by relaxin-3 neurons of the nucleus incertus.
2009
Hippocampal theta rhythm is thought to underlie learning and memory, and it is well established that “pacemaker” neurons in medial septum (MS) modulate theta activity. Recent studies in the rat demonstrated that brainstem-generated theta rhythm occurs through a multisynaptic pathway via the nucleus incertus (NI), which is the primary source of the neuropeptide relaxin-3 (RLN3). Therefore, this study examined the possible contribution of RLN3 to MS activity, and associated hippocampal theta activity and spatial memory. In anesthetized and conscious rats, we identified the ability of intraseptal RLN3 signaling to modulate neuronal activity in the MS and hippocampus and promote hippocampal the…
Binary alloys of Ge and Te: order, voids, and the eutectic composition
2008
The liquid and amorphous structures of ${\mathrm{Ge}}_{0.15}{\mathrm{Te}}_{0.85}$ and GeTe alloys are characterized using combined density functional/molecular dynamics simulations. Te is threefold coordinated, in contrast with predictions of the ``8-$N$ rule,'' and Ge atoms (fourfold coordinated) show octahedral and tetrahedral bonding angles. Cubic local environment occurs in both materials, and GeTe shows a pronounced alternation of atomic types. Tetrahedral Ge coordination is more common in the eutectic ${\mathrm{Ge}}_{0.15}{\mathrm{Te}}_{0.85}$, which comprises corner- and edge-sharing ${\mathrm{GeTe}}_{4}$ units surrounded by Te. There is no Te segregation, and the material resembles …
Low Temperature Investigation of the Thermal and Magnetic Properties of 1-d Ferrimagnetic Systems
1987
The series of structurally ordered bimetallic chains formulated as MM′ (EDTA).6H2O, in short (MM′), provides the most versatile known example of 1-dimensional ferrimagnets, since on the same structural support many different magnetic ions (Mn, Co, Ni and Cu(II)) can be selectively accommodated.1 Consequently, many choices of alternating magnetic moments with Heisenberg or Ising exchange couplings can be investigated. Moreover, taking into account that the M-M′ distances along the chain are alternating, this series could show at the same time an alternation of the exchange parameter2.
Alternating antiferromagnetic and ferromagnetic exchange interactions in the S = 1 Heisenberg chain. Theory and magnetic properties
1997
Abstract We focus on the magnetic properties of the S = 1 Heisenberg chain with alternating antiferromagnetic and ferromagnetic exchange interactions J 1 and J 2 . The magnetic behavior of this system is calculated as a function of the alternation parameter α = J 2 /| J 1 |, from a general numerical procedure based on closed spin chains of increasing length. These theoretical results are fitted to rational unified expressions, which are subsequently used to describe the magnetic behavior of a nickel (II) complex, [Ni(bipy)(N 3 ) 2 ] n , exhibiting an alternating chain structure with a dominant ferromagnetic exchange.
Observation of electronic and geometric shell structures of small silver clusters
1999
Singly charged silver clusters Open image in new window in the size range n = 17 to n = 78 have been captured and stored in a Penning trap, size selected and subjected to an electron beam which leads to further ionization as well as dissociation. The resulting abundance spectra of doubly and triply charged clusters show several features: (1) A critical size for the production of doubly charged clusters which can be understood in terms of the decay pathways as previously investigated by collision induced dissociation, (2) an odd-even alternation in the abundance of singly and doubly charged clusters which inverses sign with change of charge state, (3) prominent signals for particular doubly …
Topologically Protected Twist Edge States for a Resonant Mechanical Laser-Beam Scanner
2019
We design a one-dimensional chain of two different alternating three-dimensional elastic chiral unit cells. The chain’s topological band gap, a result of the alternation of unit cells combined with their chirality and an effective mirror symmetry, guarantees a protected edge state, corresponding to a localized twist mode with an eigenfrequency inside the one-dimensional band gap. A small axial modulation at the one end of the beam can excite this resonant twist mode at the other end of the beam, via evanescent modes in the gap. The topological robustness of the edge state allows us to add a micromirror to the other end of the beam, turning the arrangement into a resonant mechanical laser-be…
Drawings, Gestures and Discourses: A Case Study with Kindergarten Students Discovering Lego Bricks
2020
This paper presents a study aimed at investigating the didactic potentiality of the use of an artefact, useful to construct mathematical meanings concerning the coordination of different points of view, in the observation of a real object/toy. In our view, the process of meaning construction can be fostered by the use of adequate artefacts, but it requires a teaching/learning model, which explicitly takes care of the evolution of meanings, from those personal, emerging through the activities, to the mathematical ones, aims of the teaching intervention. The main hypothesis of this study is that the alternation between different semiotic systems, graphical system, verbal system and system of …
Innovazione didattica con il Situated Learning e il Work-Based Learning: una indagine esplorativa sull’Alternanza Scuola Lavoro
2019
Situated teaching methodologies constitute an innovative perspective of the teaching practice, especially if applied in the extended educational context of the school and the extra-school, as in the case of the School-Work Alternation. Conceived within the Italian law 107 of 07132015, it has initiated new ways of collaboration between the school and the professional world with a networking involvement which re-situates both disciplinary and transversal learning, in a perspective of authentic acuisition on the field. Starting from these premises, the present exploratory survey was based on the analysis of the semi-structured interviews administered to 63 School-Work Alternation referent teac…
Niektóre problemy związane z opozycją polityczną
2016
The opposition is an institution of the political regime, whose essential function is to allow alternation of power. According to the political scientist, it is a phenomenon from the sphere of governance, where different imperious and subordinate entities are in a relationship with partially common goals and partly contradictory, but remain always mutually dependent. The importance of the political opposition depends not only on the adopted institutional solutions, but primarily the political culture. Just as every society has the government it deserves, by analogy, the same is also true of the opposition.