Some results on optimality in models with heteroscedastic errors from partial optimum designs

This paper studies optimum designs for linear models when the errors are heteroscedastic. Sufficient conditions are given in order to obtainD-, A- andE-optimum designs for a complete regression model from partial optimum designs for some sub-parameters. A result about optimality for a complete model from the optimality for the submodels is included. Supported by Junta de Andalucía, research group FQM244.     

A “brer rabbit” case for reverse mandated benefits

Reverse mandated benefits is a government-mandated policy that requires employees to provide their employers with benefits that workers would not provide otherwise. Of course, only those benefits would be mandated that are worth more to employers than they cost, as determined by political authorities. My case for such a policy argues that it is at least as sensible as policies mandating that employers provide benefits to their employees that would not be provided otherwise.     

Intertemporal choice under timing risk: An experimental approach

This paper investigates how individuals evaluate delayed outcomes with risky realization times. Under the discounted expected utility (DEU) model, such evaluations depend only on intertemporal preferences. We obtain several testable hypotheses using the DEU model as a benchmark and test these hypotheses in three experiments. In general, our results show that the DEU model is a poor predictor of intertemporal choice behavior under timing risk. We found that individuals are averse to timing risk and that they evaluate timing lotteries in a rank-dependent fashion. The main driver of timing risk aversion is nothing but probabilistic risk aversion that stems from the nonlinear treatment of probabilities.     

Beheimatungsprozesse begleiten — ein Werkstattbericht

Supporting processes of belonging in supervision and coachingThe contemporary employee has to cope with frequent changes. Not only does he lose his familiar environment, he also has to find ways to familiarize himself with new places and to develop a fresh sense of belonging. This process can be understood and facilitated by interpreting the German concept of “Heimat“ as something we have to create ourselves. First experiences demonstrate the usefulness of this approach in coaching processes.     

Expected sample moments of concomitants of selected order statistics

In this paper, the task of determining expected values of sample moments, where the sample members have been selected based on noisy information, is considered. This task is a recurring problem in the theory of evolution strategies. Exact expressions for expected values of sums of products of concomitants of selected order statistics are derived. Then, using Edgeworth and Cornish-Fisher approximations, explicit results that depend on coefficients that can be determined numerically are obtained. While the results are exact only for normal populations, it is shown experimentally that including skewness and kurtosis in the calculations can yield greatly improved results for other distributions.     

From the 30s to the 60s: The folk music revival in the United States

Conclusion Woody Guthrie's ashes were spread by the wind over the water from a Coney Island, New York pier a few days after he died on Oct. 3, 1967. His wife and children, including his 19-year-old son Arlo, were present as America's greatest folksinger was laid to rest. One of the last things Woody heard before he died was Arlo's recorded voice singing the draft-dodging tale of Alice's restaurant. He must have sensed that the spirit had been passed on. Woody Guthrie died just as the second great wave of popular interest in American folk music was coming to an end. Alice's Restaurant was in many ways one of its last echoes. The symbolism could not have been more poignant. At the center of the first folk revival, Woody Guthrie was a vital source of inspiration for the second.The new generation of singer-songwriters who marked the second wave was largely composed of those with at least some contact with the new mass higher education and those multi-versities that were built to dispense it. They were neither members of a déclassé elite, as could be said of Charles and Pete Seeger and John and Alan Lomax, nor were they authentic folk singers, like Woody Guthrie. Nor could they be. By the 1960s, the conditions that had created the possibility for the first wave of the movement had been irretrievably altered. After the Second World War, with a postwar economic expansion and population explosion under way, America was a different place. Besides, the first folk revival had already claimed authenticity as its own. For the most part, if there was any aspiration toward authenticity amongst the topical singer-songwriters (those in New York City in any case), it was to be as close a copy of the first generation, Guthrie and Seeger, as possible. Purism was the second wave's answer to the authenticity of the first.Being part of an expanding generation of white, college-educated youths affected the form and content of the music that characterized the second wave. The most obvious aspect of this was the arena of performance and the audience who filled it. Gone were the union halls, the singing in working-class bars and beerhalls and at Party functions, all of which had characterized the first wave. These were replaced first by coffee shops and small clubs, either in Greenwich Village or those surrounding college campuses. The forays into the South in support of the civil-rights movement were for the most part short-lived and highly symbolic, not to say self-serving. The real mass audience arrived with the antiwar activity and was largely university centered.It was also this audience that filled the auditoriums and concert halls for the more obviously commercial performances by the singer-songwriters of the second wave. This overlapping public provided the grounds for a new mass market in folk music. Peter, Paul, and Mary, who sang in front of many mass demonstrations in protest against the war in Vietnam or in support of civil rights, were, although they saw themselves as carrying on in the spirit of the Weavers, an entirely commercial creation. In the article from the East Village Other cited above, written just after the first big concert in America against the war in Vietnam, Izzy Young angrily notes that everybody was a part of it except the people managed by Albert Grossman - Peter, Paul and Mary, and Bob Dylan. When the war in Vietnam became popular, three years later, Peter, Paul and Mary flew down to Washington, D.C. to take their place in front of the cameras.Commercial rationality was much more a factor in defining the second folk revival than the first. The possibilities were greater and the structure of the music industry was different. With a new mass market still in the process of formation and thus unspecified in terms of taste, the larger record companies could afford to take a liberal attitude and to include under their label, all the revolutionaries, as Columbia Records proudly announced in its contemporary advertising. Commercial possibilities thus were more important in shaping the musical form and content of second folk revival than politics, which were so central to the first. As opposed to the old left, the new left was a loosely organized contingent of organizations and groups with little coordination between them. In fact, many if not most of the organizations were ad hoc committees formed for a specific strike or demonstration. No one group was thus in a position to exert ideological hegemony. Following from this, at least during the period under discussion, there was little political dogmatism to be found. With no powerful organization to impose it, there was no clear political line to defend and thus to sing about. Even the notion of the people, so central to the first folk revival, was relatively absent in the second. Who were the people addressed? Certainly not the working class or even the common man. I am just a student, Sir, I only want to learn, sang Phil Ochs.During the second folk revival, the people had become the silent majority, the province of the conservative right. Neither in music nor in politics did the new left make many attempts to reach the common man in the street. The people had been massified, according to new left theory, and in the new one-dimensional mass society the grounds of political and social identity were always shifting. Besides, country music had already established itself as the musical genre of the rural, southern, western and white, common man. From a commercial point of view, there was little need to look for authenticity or the people; the market was sufficiently large and getting larger as more and more young people entered the institutions of higher education. Politically, this was not a serious problem either, as long as the aim was not revolution as it had been for the old left. It was sufficient, then, to address the masses of youngsters gathering together at institutions of higher education. If there was a revolution at foot, this was it.While the first wave practically had to invent folk music, the second could draw on the reservoir of public culture that to a large extent resulted from this invention. The networks and institutional support provided by the old left and the personal authority of a figure like Alan Lomax made possible the imposition of rather strict criteria for determining in what exactly folk music consisted. Neither networks nor gatekeepers were so determinate to the second wave. With the folksong and folksinger already invented, the new generation could pick and choose from a rather wide range of options. In addition, by the time the new left and the topical-song movement achieved at least a semblance of cohesion, folk music was already institutionally supported by radical entrepreneurs like Izzy Young and the more commercial recording industry. There were, thus, strong institutional bases for folk music outside of politics. Politics, in other words, was not the only game in town. But neither was commerce. The civil-rights movement and the new social movements that developed out of it opened for a short period a space, a public arena, in which the idea of folk music could be reinvented anew. Within this space the traditions constituted during the first wave of folk revival were experimented with and modified in light of the new social and historical context. America was not the same place in the 1960s as it had been in the 1930s and neither could its folk music be. The actors, the setting, and the songs were all different, yet still the same.In attempting to account for both this continuity and change in the two waves of folk revival we have drawn from both the cognitive approach to the study of social movements, which calls attention to the creative role of social-movement actors in the production of knowledge, and the production of culture perspective, which highlights the effects of institutional arrangements in the production of cultural goods. From the former, we have focused on the changing character of movement intellectuals, those to whom Ralph Rinzler in the epigraph that begins this article gave special place; from the latter, we have noted how, among other things, the changing nature of the recording industry helped recast the folk music revival. We hope that the foregoing has demonstrated that in combining these approaches, as well as areas of research interest, we have uncovered aspects of the folk revival others may have missed.     

Going to Pieces: Paul Monette and the Fragments of the Tribe

Author of the highly acclaimed Borrowed Time: An AIDS Memoir (1988) and winner of the 1992 National Book Award for his autobiography Becoming a Man: Half a Life Story, Paul Monette died of complications from AIDS in Los Angeles on February 12, 1995. His most recent work, Last Watch of the Night: Essays Too Personal and Otherwise (1994), is his third volume in a trilogy of autobiographical writing on growing up gay, coming-out, and living with AIDS. A graduate of Phillips Academy and Yale University, Monette received a number of awards for his writing and his work as an outspoken voice in the battle against AIDS, including the National Book Award, three Lambda Literary awards, the PEN Center West Freedom to Write Award, and three honorary doctorate degrees, from Wesleyan University, the City University of New York, and the State University of New York at Oswego. A memorial service was held for Monette on Sunday, February 19, 1995, at the Directors Guild of America on Sunset Boulevard in Los Angeles. Paul Monette was 49.     

Sensitivity of the Optimum to Perturbations of the Profit or Weight of an Item in the Binary Knapsack Problem

In the binary single constraint Knapsack Problem, denoted KP, we are given a knapsack of fixed capacity c and a set of n items. Each item j, j = 1,...,n, has an associated size or weight w_j and a profit p_j. The goal is to determine whether or not item j, j = 1,...,n, should be included in the knapsack. The objective is to maximize the total profit without exceeding the capacity c of the knapsack. In this paper, we study the sensitivity of the optimum of the KP to perturbations of either the profit or the weight of an item. We give approximate and exact interval limits for both cases (profit and weight) and propose several polynomial time algorithms able to reach these interval limits. The performance of the proposed algorithms are evaluated on a large number of problem instances.     

Buchbesprechungen

Ohne Zusammenfassung