Regular Action in Rings

2013 ◽  
Vol 42 (2) ◽  
pp. 872-879 ◽  
Author(s):  
Juncheol Han ◽  
Sangwon Park
Keyword(s):  
Regular Action

Intrinsic Excitability of Cholinergic Neurons in the Rat Parabigeminal Nucleus

2007 ◽  
Vol 98 (6) ◽  
pp. 3486-3493 ◽  
Author(s):  
C. Alex Goddard ◽  
Eric I. Knudsen ◽  
John R. Huguenard
Keyword(s):  
Spontaneous Activity ◽  
Action Potentials ◽  
Cholinergic Neurons ◽  
Spontaneous Firing ◽  
Current Clamp ◽  
Excitatory Neurotransmitter ◽  
Voltage Dependent ◽  
Regular Action ◽  
Cell Current ◽  
Parabigeminal Nucleus

Cholinergic neurons in the parabigeminal nucleus of the rat midbrain were studied in an acute slice preparation. Spontaneous, regular action potentials were observed both with cell-attached patch recordings as well as with whole cell current-clamp recordings. The spontaneous activity of parabigeminal nucleus (PBN) neurons was not due to synaptic input as it persisted in the presence of the pan-ionotropic excitatory neurotransmitter receptor blocker, kynurenic acid, and the cholinergic blockers dihydro-beta-erythroidine (DHβE) and atropine. This result suggests the existence of intrinsic currents that enable spontaneous activity. In voltage-clamp recordings, IH and IA currents were observed in most PBN neurons. IA had voltage-dependent features that would permit it to contribute to spontaneous firing. In contrast, IH was significantly activated at membrane potentials lower than the trough of the spike afterhyperpolarization, suggesting that IH does not contribute to spontaneous firing of PBN neurons. Consistent with this interpretation, application of 25 μM ZD-7288, which blocked IH, did not affect the rate of spontaneous firing in PBN neurons. Counterparts to IA and IH were observed in current-clamp recordings: IA was reflected as a slow voltage ramp observed between action potentials and on release from hyperpolarization, and IH was reflected as a depolarizing sag often accompanied by rebound spikes in response to hyperpolarizing current injections. In response to depolarizing current injections, PBN neurons fired at high frequencies, with relatively little accommodation. Ultimately, the spontaneous activity in PBN neurons could be used to modulate cholinergic drive in the superior colliculus in either positive or negative directions.

Soviet Policy Double think

2018 ◽  
pp. 18-30
Author(s):  
Anna L. Bailey
Keyword(s):  
Gain Control ◽  
Alcohol Problems ◽  
Alcohol Policy ◽  
Soviet Society ◽  
Soviet Leadership ◽  
Power Shift ◽  
Short Period ◽  
Regular Action ◽  
Almost All

Explores the postwar Soviet regime’s contradictory doublethink on alcohol: publicly denying that it was a problem in Soviet society, while simultaneously taking regular action to tackle alcohol problems. Explains why a radical anti-alcohol campaign was enacted under Gorbachev in 1985, despite the fact that almost all Soviet departmental interests were opposed to it. A long-term ideological shift had seen the Soviet leadership increasingly regard rising consumption as problematic, but it took a contingent power shift under Gorbachev to enable temperance activists to gain control over alcohol policy – albeit only for a very short period.

scholarly journals Regular actions of simple algebraic groups on projective threefolds

1989 ◽  
Vol 116 ◽  
pp. 139-148 ◽  
Author(s):  
Tetsuo Nakano
Keyword(s):  
Algebraic Groups ◽  
Finite Subgroup ◽  
Fano Threefolds ◽  
Simple Algebraic Group ◽  
Mori Theory ◽  
Projective Threefolds ◽  
Classical Work ◽  
Regular Action ◽  
Small Codimension

The purpose of this note is to study regular actions of simple algebraic groups on projective threefolds as an application of the theory of algebraic threefolds, especially Mori Theory and the theory of Fano threefolds (cf. Mori [11], Iskovskih [7, 8]). The motivation for this study is as follows. In a series of papers, Umemura, in part jointly with Mukai, has classified maximal connected algebraic subgroups of the Cremona group of three variables and also constructed minimal rational threefolds which correspond to such subgroups (cf. Umemura [16-19], Mukai-Ume-mura [12]). In particular, Umemura and Mukai studied in [12] the SL(2, C)-equivariant smooth projectivization of SL(2, C)/G, where G is a binary icosahedral or octahedral subgroup of SL(2, C). The study of equivariant smooth projectivization of SL(2, C)/G for any finite subgroup G has been completed along their lines in Nakano [14]. The main trick of these studies is the investigation of equivariant contraction maps of extremal rays in the context of Mori Theory [11]. In this note, we apply a similar idea to projective threefolds with a regular action of a simple algebraic group and determine which simple algebraic groups can act regularly and nontrivially on projective threefolds and in which fashion. We also need some standard (but difficult) facts from the theory of Fano threefolds. For the precise statement, see Theorem 1 in the main text. For the proof of this theorem, we need a classification of closed subgroups of simple algebraic groups of codimension 1 and 2, which could be derived easily from the classical work of Dynkin [4]. However, we shall give a geometric proof independent of [4] which leads up directly to the proof of Theorem 1. On the whole, we shall establish by geometric methods the scarcity of closed subgroups of small codimension in simple algebraic groups, which is implied in Dynkin [4].

IMPRIMITIVE REGULAR ACTION IN THE RING OF INTEGERS MODULO n

2012 ◽  
pp. 182-195
Author(s):  
JUNCHEOL HAN ◽  
YANG LEE ◽  
SANGWON PARK
Keyword(s):  
Ring Of Integers ◽  
Regular Action
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