Partial rupture of a locked patch of the Sumatra megathrust during the 2007 earthquake sequence

The great Sumatra–Andaman earthquake and tsunami of 2004 was a dramatic reminder of the importance of understanding the seismic and tsunami hazards of subduction zones [1,2,3,4]. In March 2005, the Sunda megathrust ruptured again, producing an event [5] of moment magnitude (Mw) 8.6 south of the 2004 rupture area, which was the site of a similar event in 1861 (ref. 6). Concern was then focused on the Mentawai area, where large earthquakes had occurred in 1797 (Mw = 8.8) and 1833 (Mw = 9.0) [6,7]. Two earthquakes, one of Mw = 8.4 and, twelve hours later, one of Mw = 7.9, indeed occurred there on 12 September 2007. Here we show that these earthquakes ruptured only a fraction of the area ruptured in 1833 and consist of distinct asperities within a patch of the megathrust that had remained locked in the interseismic period. This indicates that the same portion of a megathrust can rupture in different patterns depending on whether asperities break as isolated seismic events or cooperate to produce a larger rupture. This variability probably arises from the influence of non-permanent barriers, zones with locally lower pre-stress due to the past earthquakes. The stress state of the portion of the Sunda megathrust that had ruptured in 1833 and 1797 was probably not adequate for the development of a single large rupture in 2007. The moment released in 2007 amounts to only a fraction both of that released in 1833 and of the deficit of moment that had accumulated as a result of interseismic strain since 1833. The potential for a large megathrust event in the Mentawai area thus remains large

Industrialization in advanced rural communities : the Israeli kibbutz

22 p

The Kibbutz: Issues of Existence and Models of Survival

As of the mid 1980s, many kibbutzim became deeply indebted and went into grave economic troubles, which affected adversely both their competitiveness and the spiritual resilience of the kibbutz society. The combination of economic and ideological crises led to a crossroad from which the kibbutz may emerge as a reformed kibbutz, with a variety of new ideas as to the direction of the reform. It could also become, however, a disintegrated kibbutz with various options how to continue life in an ex-kibbutz village. Finally, kibbutz members may refrain from taking redressing initiatives and kibbutzim may enter a stage of gradual languor and demographic decline. This paper examines some of the more specific reasons which led to the arrival of the kibbutzim to the present crossroad, and the various options on the agenda for the future of the kibbutz today

The Importance of Behaving Altruistically: Altruism as an Efficiency Boosting Factor in the Kibbutz

The constitution of the kibbutz is loaded with behavioral constraints which, under normal micro-economic assumptions, should lead the kibbutz economy to intrinsically inefficient performance, in the sphere of consumption as well as in the sphere of production. Phenomena such as the provision of consumers' goods and services at a zero price would, in the "normal" utility maximizing environment, result in a highly inefficient and wasteful utilization of those consumer goods. In parallel, production in a system without "normal" controlling devices and without remuneration in accordance with contribution, should lead to phenomena of "free riders" and to diminution of competitiveness on the market place. Empirical observation of the economic performance of the kibbutz, up to the mid eighties suggested, however, that this was not the case. The article raises the thesis that the reason for such a deviation of the empirical observations from the anticipations, in accordance with the standard economic theory, can be explained by the existence of strong altruistic elements in the utility function of the typical kibbutz member. Such a utility function implies that the individual is capable to derive utility not only from the possession of goods and services for himself, but also from his fellow kibbutz members' material welfare. If such altruistic elements are present in the preference patterns of the kibbutz members, the kibbutz constitution need not diminish the competitive edge of the kibbutz production, but, on the contrary, it may even enhance overall economic efficiency. One of the principal reasons for the economic decline of the kibbutzim in the last two decades seems to be the gradual disappearance of the altruistic motivations from the behavior of most kibbutz members, and the substitution of that unique "irrational", altruistically loaded, atmosphere by "normal" utility maximizing attitude to the kibbutz

Recommender systems for the conference paper assignment problem

2. We evaluate our models not just in terms of prediction accuracy but in terms of the end-assignment quality. Using a linear programming-based assignment optimization formulation, we show how our approach betarXiv:0906.4044v

Genetic Kinship and Social Structure in a Herd of Square-Lipped Rhinoceroses

Zoos and zoological parks serve as genetic and demographic reserves for strengthening endangered populations and reestablishing extinct populations in the wild. Knowing the genetic ties within captive populations is a very helpful tool for successful reproductive management. In the present study we addressed kinship relationships and behavior among rhinoceroses (Ceratotherium simum simum) raised at the Zoological Center, Tel Aviv/Ramat Gan, Israel, with the hope of identifying reasons for the declining rate of reproduction within the herd. We used the random amplified polymorphic DNA (RAPD) technique to reveal the paternity of the rhinos born at the park. In this way, we identified the paternity of five out of seven young born in the herd, which are currently in Ramat Gan. One male accounted for three (37.5%) births, and two other males accounted for one each. The paternity of the two other animals is unknown and may be of animals that are no longer in the Zoological Center. The genetic determinations were accompanied by behavioral observations, which enabled us to determine the social dynamics in the herd. This study suggests that there are at least three contributing factors to the reproductive decline in the herd: 1) a surplus of males, 2) exclusion of potentially reproductive males from the breeding stock, and 3) specific behavioral and physiological problems in some members of the herd