Search results for "alternation"
showing 10 items of 26 documents
Large Quadratic Hyperpolarizabilities with Donor–Acceptor Polyenes Exhibiting Optimum Bond Length Alternation: Correlation Between Structure and Hype…
1997
Donor-acceptor polyenes of various lengths, and that combine aro- matic electron-donating moieties with powerful heterocyclic electron-withdraw- ing terminal groups, have been synthe- sized and characterized as efficient non- linear optical (NLO) chromophores. Their linear and nonlinear optical proper- ties have been investigated, and variations in these properties have been related to ground-state polarization (dipole p) and structure. In particular, unprecedented quadratic hyperpolarizabilities (p) have been achieved (up to p(0) =I500 x 10-30esu) by reduction of the bond- length alternation (BLA) in the polyenic chain. In each series of homologous com-
Does "whole-word shape" play a role in visual word recognition?
2002
To analyze the impact of outline shape on visual word recognition, the visual pattern of the stimuli can be distorted by size alternation. Contrary to the predictions of models that rely on outline shape (Allen, Wallace, & Weber, 1995), the effect of size alternationwas greater for low-frequency words than for high-frequency words in a lexical decision task (Experiment 1). In Experiment 2, the effect of case type (lowercase vs. UPPERCASE) occurred for low-frequency words, but not for high-frequency words. The effect of neighborhood size was remarkably similar in the two experiments. The results can be readily explained in the framework of a resonance model (Grossberg & Stone, 1986), in whic…
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…
Rozliczalność jako element jakości procesu demokratycznego w systemie instytucjonalnym III Rzeczypospolitej
2018
The term “accountability” refers to a manner of assuming responsibility, in particular a relevant verifi - cation of particular actions and processes located in time and assigned to a concrete subject. Usu ally the following two types of accountability are identifi ed: inter-institutional (horizontal) accountability and electoral (vertical) accountability. Accountability applies primarily to the executive branch of government, but it is included in the much wider range of the accountability of the particular institutions of a political system. It constitutes an element of the quality of democracy. There have been oscillations in the level of accountability in the political system of the Pol…
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.
Modele ustrojowe opozycji parlamentarnej w strukturze systemu politycznego Zjednoczonego Królestwa, Republiki Federalnej Niemiec i V Republiki Francu…
2017
The right to oppose the current government is an indispensable element of the pluralist system of liberal democracy. A parliamentary opposition may function in various organisational forms. It comprises political groups and factions which do not participate in the formation of the government, adopt a critical attitude towards the programme of the executive branch, and offer alternative solutions with respect to programmes and the staffi ng of ministerial positions. This study of the three cases of the United Kingdom, Germany and France confi rms that, besides the common attribute of representing a political orientation different from that of the current government, an opposition is distingu…
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.
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…
Subject case alternation in negated existential, locative, and possessive clauses in Latvian
2018
[full article and abstract in English]
 The goal of this article is to analyse the alternation between the genitive and nominative cases in Latvian. As the alternation between genitive and nominative cases is possible in all clauses in which the verb būt ‘to be’ is used as an independent verb, this article examines existential, locative, and also possessive clauses, while also demonstrating that distinguishing these clause types is problematic for Latvian utilising the criteria given in the linguistic literature. Clauses containing the negative form of būt ‘to be’, i.e. nebūt, form the foundation of those selected for this study, as only in these sentences the genitive/nominative alter…
Field-free two-direction alignment alternation of linear molecules by elliptic laser pulses
2005
We show that a linear molecule subjected to a short specific elliptically polarized laser field yields postpulse revivals exhibiting alignment alternatively located along the orthogonal axis and the major axis of the ellipse. The effect is experimentally demonstrated by measuring the optical Kerr effect along two different axes. The conditions ensuring an optimal field-free alternation of high alignments along both directions are derived.