On Super and Hereditarily Hopfian and co-Hopfian Abelian Groups

The notions of Hopfian and co-Hopfian groups have been of interest for some time. In this present work we characterize the more restricted classes of hereditarily Hopfian (co-Hopfian) and super Hopfian (co-Hopfian) groups in the case where the groups are Abelian

R-Hopfian and L-co-Hopfian Abelian Groups

The notions of Hopfian and co-Hopfian groups are well known in both non-commutative and Abelian group theory. In this work we begin a systematic investigation of natural generalizations of these concepts and, in the case of Abelian p-groups, give a complete characterization of the generalizations in terms of the original concepts

Algebraic Entropies, Hopficity and co-Hopficity of Direct Sums of Abelian Groups

Necessary and sufficient conditions to ensure that the direct sum of two Abelian groups with zero entropy is again of zero entropy are still unknown; interestingly the same problem is also unresolved for direct sums of Hopfian and co-Hopfian groups. We obtain sufficient conditions in some situations by placing restrictions on the homomorphisms between the groups. There are clear similarities between the various cases but there is not a simple duality involved

Mechano- and Photoresponsive Behavior of a Bis(cyanostyryl)benzene Fluorophore

The mechanoresponsive behaviour and photochemical response of a new bis(cyanostyryl)benzene fluorophore (CSB-5) were investigated. Green fluorescence with λem,max of 507 nm was found for CSB-5 in chloroform solution, mirroring the behaviour of a previously reported similar dye (CSB-6).On the other hand, crystalline samples of CSB-5 exhibited orange fluorescence with λem,max of 620 nm, attributable to excimer emission.Although the emission color change was not clearly noticeable by naked eye, CSB-5 exhibited mechanochromic luminescence, due to transformation into the amorphous state upon grinding the crystalline powder.Interestingly, rubbed films of CSB-5 prepared on glass substrates exhibited a pronounced emission color change from orange to green when exposed to UV light.This response is the result of a photochemical reaction that occurs in the amorphous state and which causes a decrease of the excimer emission sites so that the emission color changes from excimer to monomer.The crystalline material did not display such a photoinduced emission color change and the difference in photochemical reactivity between crystalline and amorphous states was exploited to pattern the emission color of rubbed films

Tsunami field survey of the 1992 Nicaragua earthquake

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95368/1/eost9614.pd

Stress relaxation arrested the mainshock rupture of the 2016 Central Tottori earthquake

地震の破壊はなぜ止まるのか? --2016年鳥取県中部地震の断層サイズを決めたもの--. 京都大学プレスリリース. 2021-08-12.After a large earthquake, many small earthquakes, called aftershocks, ensue. Additional large earthquakes typically do not occur, despite the fact that the large static stress near the edges of the fault is expected to trigger further large earthquakes at these locations. Here we analyse ~10, 000 highly accurate focal mechanism solutions of aftershocks of the 2016 Mw 6.2 Central Tottori earthquake in Japan. We determine the location of the horizontal edges of the mainshock fault relative to the aftershock hypocentres, with an accuracy of approximately 200 m. We find that aftershocks rarely occur near the horizontal edges and extensions of the fault. We propose that the mainshock rupture was arrested within areas characterised by substantial stress relaxation prior to the main earthquake. This stress relaxation along fault edges could explain why mainshocks are rarely followed by further large earthquakes

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短距離走におけるスタート態勢の動作では, スタートの位置についた静止の姿勢においては, 精神的な安定の要素が必要で, 特に意識の集中力が重要な要因となる。ピストルの合図で発進動作を開始する際, 両手をすばやく地面より離すと同時に, 後方の足をスターティングブロックより機敏に離すことも修得する必要がある。さらに前方に位置した足を「支点」として, 前方の足の膝部が十分伸びきるように留意する。十分膝部が伸びきらない場合には, 下肢の筋力の強化にたいする5m疾走の反復訓練が特に重要となる。スタート動作において, 前方への「重心の移動」が悪く「推進力」にも欠けるような動作のときには, 運動動作の反復訓練による強化も, 走運動の技術指導として必要となり, また走運動でも, 疾走時間の長短によって体力が評価される場合もあるから, 特に動作の時間経過について, 個別的な指導を十分行なうことが必要であろう。It is well known that the starting motions are an important factor for good sprint results. This study was conducted with coaching sprint starts in mind. Forty eight pupils and students participated in this study. A high speed movie camera and electronic stop watch were used to analyze the starting motions. A comparison between the well trained runners and untrained pupils and students was made and the following results were obtained. In the sprint both hands should leave the ground and the foot furtherest back in the starting block should be brought forward to start the running motion as soon as possible after the gun. Anticipation is also important. On top of this coaching a good sprinter to use his or her forward foot as a fulcrum, extending it as far as possible gives a faster start. The best way to strengthen the muscles in the lower extremities is to repeat start motions and following five meter run over and over again