A Formula That Generates Hash Collisions

We present an explicit formula that produces hash collisions for the Merkle-Damg{\aa}rd construction. The formula works for arbitrary choice of message block and irrespective of the standardized constants used in hash functions, although some padding schemes may cause the formula to fail. This formula bears no obvious practical implications because at least one of any pair of colliding messages will have length double exponential in the security parameter. However, due to ambiguity in existing definitions of collision resistance, this formula arguably breaks the collision resistance of some hash functions.Comment: 10 page

Metamorphosis and identity : psychoanalytical notes to Miyazaki’s Spirited Away and Howl’s Moving Castle

Far greater liberties can be taken by animation than by live-action films The possibilities of the narratives are enriched by unrestricted visual images that offer unique means of exploring and portraying states of desire, conscious and unconscious realities, as well as different layers of relationships and experiences. This leads to a fusion of the traditional and modern roles of representation. Anime from acclaimed Japanese director Hayao Miyazaki, particularly the Academy Award winner Spirited Away (Sen to Chihiro no Kamikakushi, 2003) and Oscar-nominated Howl’s Moving Castle (Hauru no Ugoku Shiro, 2004), which in recent years have acquired a global cult status, offer new perspectives on human subjectivity. Through their playful use of the motif of transformation, striking similarities in the development of the plots and ambiguous dénouements, the movies problematize the fundamental question of identity, representing a close illustration of some of the core psychoanalytical concepts found in Lacanian theory

Why is health treatment for the elderly less expensive than for the rest of the population? Health care rationing in Germany

The consequences of population ageing for the health care system and health care costs may be less severe than is commonly assumed. Hospital discharge data from Germany’s largest health insurer (AOK) show that the care of patients during their last year of life is less costly if they die at an advanced age. As a multivariate analysis reveals, oldest old patients receive less costly treatment for the same illness than younger patients. Health care is informally rationed according to the age of the patient. The data also indicate that age-related rationing may be more pronounced in Germany than in the United States. (AUTHOR)

Why Are Middle-Aged People so Depressed?: Evidence from West Germany

Does happiness vary with age? The evidence is inconclusive. Some studies show happiness to increase with age (Diener et al. 1999; Argyle 2001). Others hold that the association is U-shaped with either highest depression rates (Mroczek and Christian, 1998; Blanchflower and Oswald, 2008) or highest happiness levels occurring during middle age (Easterlin, 2006). Current studies suffer from two shortcomings. Firstly, they do not control for three confounding time variables: age, period and cohorteffects. Secondly, all empirical research lacks a theoretical explanation as to why age affects happiness. The purpose of our analysis is to contribute to closing both of these research gaps. A social investment model frames the dynamics of happiness across the life-span. The empirical test draws on West German panel data that followed individuals from 1984 to 2005. Descriptive analysis shows a cubic age function with the lowest level at middle age. However, hierarchical three-level variance component models (Rabe-Hesketh and Skrondal, 2005), find significant differences across pre-war and post-war cohorts, baby boomers and offspring of the baby bust as well as deviations during reunification. Yet, cohort and period effects account for less than 10% of the variance. (Un)happiness in midlife is more strongly determined by gender-specific occasional influences and individual characteristics. Both define objective and subjective returns of professional and personal life investments. Thesesocial investment decisions date back to early adulthood and bear a high risk of failure during midlife. Unforeseen consequences and long-term private and professional commitments make it costly to adjust, but at the same time new investments may pay off in a pro-longed future. This dilemma turns many middle-aged people into "frustrated achievers".Happiness, subjective well-being, gendered life-course, inequality, APC effects (Age-Period-Cohort effects), multi-level analysis, Germany

The ratchet effect in a two lag setting and the mitigating influence of yardstick competition

In order to increase efficiency in the provision of power distribution networks, the German regulator Bundesnetzagentur plans to implement revenue cap regulation together with yardstick competition. Revenue cap regulation could bear the ratchet effect: cost minimization need not to be optimal for the operator who anticipates that his revenue cap will become adjusted according to his cost performance. The regulator could extract all the rent by lowering an operator’s revenue cap to the level of costs he revealed to be possible for him to reach. The ratchet effect could be mitigated by yardstick competition at which the level of revenues that is allowed to one operator is tied to the performance of others that are comparable to him. One will only be allowed to accumulate revenues that recover the least cost level that has been adopted within the group of comparable decision makers. In a setting of two sequential regulatory lags, this paper examines the occurence of the ratchet effect and the mitigating influence that yardstick competition has on it.ratchet effect, yardstick competition, regulation

Girls preferred? Changing patterns of gender preferences in the two German states

Parental preferences for the sex of children are a prominent subject of study in some Asian and African countries where sex-selective behavior has led to skewed sex-ratios. In Europe or North-America, by contrast, cross-sectional data does not reveal any clear pattern of sex-preferences. However, this does not mean that people are indifferent to the sex of their children. Taking a longitudinal perspective, this paper shows how sex-preferences in Germany have changed over time and in response to changes in welfare regime. Based on German cohort data, event-history models reveal a significant boy-preference among women born before 1910 during the German Reich. After the world war II, women in West-Germany never developed a clear sex-preference, but cohorts born in the former German Democratic Republic (GDR) show a significant preference for girls. This pattern is absorbed by the pro-family policy that was launched by the socialist regime during the seventies. In conclusion, the paper argues that the process of modernization does not neutralize sex-preferences as is often assumed. Rather, it may give rise to diverging sex-preferences depending on the specific type of welfare regime. (AUTHOR)

The ratchet effect in a two lag setting and the mitigating influence of yardstick competition

In order to increase efficiency in the provision of power distribution networks, the German regulator Bundesnetzagentur plans to implement revenue cap regulation together with yardstick competition. Revenue cap regulation could bear the ratchet effect: cost minimization need not to be optimal for the operator who anticipates that his revenue cap will become adjusted according to his cost performance. The regulator could extract all the rent by lowering an operator's revenue cap to the level of costs he revealed to be possible for him to reach. The ratchet effect could be mitigated by yardstick competition at which the level of revenues that is allowed to one operator is tied to the performance of others that are comparable to him. One will only be allowed to accumulate revenues that recover the least cost level that has been adopted within the group of comparable decision makers. In a setting of two sequential regulatory lags, this paper examines the occurence of the ratchet effect and the mitigating influence that yardstick competition has on it.ratchet effect, yardstick competition, regulation