A stable estimator of the information matrix under EM for dependent data

This article develops a new and stable estimator for information matrix when the EM algorithm is used in maximum likelihood estimation. This estimator is constructed using the smoothed individual complete-data scores that are readily available from running the EM algorithm. The method works for dependent data sets and when the expectation step is an irregular function of the conditioning parameters. In comparison to the approach of Louis (J. R. Stat. Soc., Ser. B 44:226–233, 1982), this new estimator is more stable and easier to implement. Both real and simulated data are used to demonstrate the use of this new estimator.     

An Analysis of Stability Sets in pure Coordination Games

We calculate the Lebesgue–measures of the stability sets of Nash-equilibria in pure coordination games. The results allow us to observe that the ordering induced by the Lebesgue–measure of stability sets upon strict Nash-equilibria does not necessarily agree with the ordering induced by risk–dominance. Accordingly, an equilibrium selection theory based on the Lebesgue–measure of stability sets would be necessarily different from one which uses the Nash-property as a point of orientation.     

Density-Tempered Marginalized Sequential Monte Carlo Samplers

We propose a density-tempered marginalized sequential Monte Carlo (SMC) sampler, a new class of samplers for full Bayesian inference of general state-space models. The dynamic states are approximately marginalized out using a particle filter, and the parameters are sampled via a sequential Monte Carlo sampler over a density-tempered bridge between the prior and the posterior. Our approach delivers exact draws from the joint posterior of the parameters and the latent states for any given number of state particles and is thus easily parallelizable in implementation. We also build into the proposed method a device that can automatically select a suitable number of state particles. Since the method incorporates sample information in a smooth fashion, it delivers good performance in the presence of outliers. We check the performance of the density-tempered SMC algorithm using simulated data based on a linear Gaussian state-space model with and without misspecification. We also apply it on real stock prices using a GARCH-type model with microstructure noise.     

The Role of Insurance in Social Protection in Latin America

Social protection schemes in Latin America face serious short falls in the financial resources available to meet their needs. New types of insurance envisaged in reforms should help to contain costs and increase coverage. However, in strengthening schemes' coverage it is highly probable that considerable demand for additional financial resources will arise to address the need to introduce the principle of solidarity into the system. This article examines reforms in the financing of social security for healthcare and pensions, highlighting the implications of various public-private combinations for financial management and coverage.     

On dual power assignment optimization for biconnectivity

Topology control is an important technology of wireless ad hoc networks to achieve energy efficiency and fault tolerance. In this paper, we study the dual power assignment problem for 2-edge connectivity and 2-vertex connectivity in the symmetric graphical model which is a combinatorial optimization problem from topology control technology.The problem is arisen from the following origin. In a wireless ad hoc network where each node can switch its transmission power between high-level and low-level, how can we establish a fault-tolerantly connected network topology in the most energy-efficient way? Specifically, the objective is to minimize the number of nodes assigned with high power and yet achieve 2-edge connectivity or 2-vertex connectivity.We addressed these optimization problems (2-edge connectivity and 2-vertex connectivity version) under the general graph model in (Wang et al. in Theor. Comput. Sci., 2008). In this paper, we propose a novel approximation algorithm, called Candidate Set Filtering algorithm, to compute nearly-optimal solutions. Specifically, our algorithm can achieve 3.67-approximation ratio for both 2-edge connectivity and 2-vertex connectivity, which improves the existing 4-approximation algorithms for these two cases.     

Orpheus wounded: The experience of pain in the professional worlds of the piano

Conclusions None of the three worlds within the field of professional piano playing has adequately confronted the problem of pain, partly because its causes and treatment could be easily assigned to another world. The medical world could blame pain on misuse; the virtuoso world on lack of genius or hard work; the pedagogical world on bad teaching or lack of talent. Each world, for its own reasons, has managed either to skirt the problem of pain outright or to develop techniques and languages that fail to offer general remedies, or worse, exacerbate the amount of pain pianists endure. In the meantime, market competition in a shrinking concert market has increased, together with audience dependence upon charismatic virtuosity. The more compact virtuoso world, populated by ever larger numbers of hopeful pianists, creates intense competition in which the causes stimulating pain multiply.A number of factors have inhibited both the private and public acknowledgment of pain. First, there are the demands of maintaining a professional career as a pianist. It has been difficult if not impossible for concert artists to admit they are in pain, because it would threaten their careers. Second, there is the romantic image of pain: the belief that pain is necessary and inevitable in order to be a virtuoso. This factor is related to a culture of mastery (or masculinity): the ideal of a stoical master in control of his body, able to surmount such mundane obstacles as pain. Third, the emotional identification of the young prodigy with their teacher; the belief that the teacher is giving the young pianist a precious skill, potential career as an artist, and would not allow unnecessary pain. Psychologically it is difficult to challenge teaching maxims that lead to discomfort. Instead, musicians in pain blame themselves.Complementary factors are leading to a growing ability to acknowledge pain. First, what might be called a culture of femininity emphasizing awareness of the body may be increasing. It is interesting to speculate whether women teachers are more likely than male teachers to emphasize that playing should be comfortable. Are women pianists less likely to suffer pain than male pianists because of less commitment to the ideal of control, power, and mastering pain?Second, the rise of the world of performing-arts medicine itself provides a refuge, a safe place where pain can be legitimately acknowledged. Medicalization takes pain out of the virtuoso world and neutralizes its emotional and professionally charged character, whether or not the doctors have solutions.Third, the diffusion of awareness that pain is not one's individual problem, as such examples as Gary Graffman and Leon Fleisher have become publicly acknowledged. However, once acknowledged, there may be a contagion effect. Is it possible that the reported incidence of pain is a result of a kind of mass hysteria? This possibility raises a knotty methodological issue: How much can we trust subjective reports of pain? Once people are asked if they have physical problems, they may become aware of them. Or, the individual may discover or remember an analog to parental or teacher abuse. Such an attempt to explain away the discovery of widespread pain as hysteria seems highly unlikely.If injuries to hand and arm can be shown to be caused by keyboards, not just pianos, but computers too, then legal institutions may get involved in this complex story. Here we are dealing with a future possibility, but an ominous one. Repetitive stress injury (RSI) has been charged by persons suffering pain after long hours on the computer, and more than 2,000 suits have been filed against makers of computer equipment. The U.S. Occupational Safety and Health Administration in October, 1994, announced a plan for rules that would make it harder for employers to claim they didn't know about the problem.... For the delicate muscles and tendons in the fingers and wrists, rapidly pushing buttons [or piano keys] thousands of times an hour can be just as stressful [as driving screws or slicing carcasses in a meat-processing plant]. The Time magazine article blithely explains the consequences of these stresses as creating tiny tears in the muscles and tendons, which become inflamed. If the tissues aren't given time to heal properly, scarring can occur. That the hand motions required for the piano and computer keyboards are essentially the same, in terms of body physiology, has been finally realized. A book giving concrete instructions on how to play both types of keyboards safely and efficiently was published in 1995, although the author, a concert pianist, focusses upon computers, with an accurate eye on a far bigger market for the book. It is curious in a society like ours that technical solutions have not been explored at all as a cure for pain. Interviews with members of manufacturing companies at the National Conference on Piano Pedagogy in October, 1994 indicated that there is practically no work being done in this area. Even though certain technological solutions readily present themselves (as they do in the computer industry, for example), having to with changing the physical arrangement of the keyboard, nothing has been seriously considered. Neither have pedagogical learning routines in electronic keyboards reached the sophistication that is now technically possible. This lack is fortunate (and perhaps not accidental) because Steinway and Baldwin might become subject to suits on exactly the same grounds as IBM has become liable.If pain is still slipping through the cracks among the various worlds constituting the field of professional piano playing, it is because in each of these worlds there are forces at work either producing pain or explaining it in individualistic terms. The pervasive experience of pain is an unintended consequence of the mutual actions of the institutions involved in creating and propagating piano music in our culture. Unintended consequences put stubborn difficulties in the path of change precisely because there are no concrete intentions or interests at stake that are producing the problem. As the examples above show, however, the mere recognition of pain as a reality pushes for a mutual opening up and interaction among these only partially overlapping worlds. If the issue of pain among pianists becomes forcibly raised - well beyond academic discourse and professional interest groups - in the broad community of piano playing and the even broader realm of the media, each of these institutional worlds faces deep challenges. At this moment it is impossible to know what might happen if the issue of pain is finally confronted as a joint problem for these social worlds. Within physiological limits, the issue is whether knowledge exists or can be acquired about how to play the piano in a way that will minimize the occurrence of pain. We have been concerned with the institutional and individual processes that both cause pain and stand in the way of obtaining a suitable cure for injured pianists. As we have shown, the institution with which pain is traditionally associated in our culture - medicine - plays only an accompanying part in this story. As David B. Morris notes in his recent work on the cultural embeddedness of pain. Certainly we can take comfort in assuming that pain obeys the general laws of human anatomy and physiology that govern our bodies ... however, the culture we live in and our deepest personal beliefs subtly or massively recast our experience of pain. The story of how our minds and our cultures continuously reconstruct the experience of pain demands that we look beyond the medicine cabinet. For the sociologist, what is most theoretically and substantively compelling about the relatively esoteric tribulations of pain-ridden performing artists is precisely how, within the experience of emotional and physical distress, deeply individual physical states and emotions cannot be separated from institutional pressures and constraints. And not only does the scourge of pain among pianists shatter the dichotomy of individual versus institution, it also provides a palpable example of how pain in our culture exists in the shadow of multiple social worlds.

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当代大学生竞争情绪体验特点研究

以大学一、二、三和四年级550名学生为被试,采用大学生竞争调查问卷,研究其竞争后情绪体验的发展特点。结果发现：（1）在不同竞争环境下,大学生的情绪体验没有年龄差异。在竞争激烈环境下,女大学生比男大学生更容易产生消极情绪。学生干部的积极情绪体验显著高于普通学生,前者的消极情绪体验显著低于后者。（2）在竞争失败后,一年级大学生有更低的挫折体验,四年级大学生有更高的嫉妒体验;女大学生比男大学生有更高的挫败感和疲惫感。在竞争成功后,男大学生比女大学生有更高的自大体验,学生干部的自大体验显著低于普通同学。     

Partners in life: Unmarried couples in Hungary

Non-marital cohabitation in Hungary is documented using data from the 1970 and 1980 censuses and the 1984 microcensus. Observed patterns contrast with those in several other countries, particularly those of western and northwestern Europe. Firstly, in Hungary unmarried couples or ‘partners in life’ are more common, and their proportion is increasing more rapidly, among the previously married than among the single. Secondly, both among the single and the previously married, mothers are more likely than childless women to be cohabiting. Thirdly, although proportions cohabiting are higher in urban than in rural areas, partners in life are concentrated among those with the lowest educational level.