Optimal Single-Choice Prophet Inequalities from Samples

We study the single-choice Prophet Inequality problem when the gambler is given access to samples. We show that the optimal competitive ratio of $1/2$ can be achieved with a single sample from each distribution. When the distributions are identical, we show that for any constant $\varepsilon > 0$, $O(n)$ samples from the distribution suffice to achieve the optimal competitive ratio ($\approx 0.745$) within $(1+\varepsilon)$, resolving an open problem of Correa, D\"utting, Fischer, and Schewior.Comment: Appears in Innovations in Theoretical Computer Science (ITCS) 202

A Conductor\u27s Guide to Alec Roth\u27s A Time to Dance

The purpose of this monograph is to provide a comprehensive analysis and conductor’s guide for Alec Roth’s masterwork, A Time to Dance. This study will explore the origins of this work, provide rehearsal and performance considerations, and bring greater attention to its composer, Alec Roth. Compared to his English contemporaries, Alec Roth’s (b.1948) music is lesser-known within the British tradition. Roth composes for choir, orchestra, and musical theatre and is also well-known for his contributions to both the guitar and gamelan repertory. His music spans a variety of languages, voicings, orchestrations, and levels of difficulty, as he is also noted for his work with children’s choirs. Roth’s music has been performed by the choirs of St. Paul’s Cathedral, Westminster Abbey, The Sixteen, and Ex Cathedra with whom he premiered A Time to Dance in 2012.[1] A Time to Dance demonstrates a diverse poetic and musical landscape, celebrating the “times and seasons of human existence.”[2]This study will focus on textual and musical analyses of the work as well as performance consideration for the prospective conductor. It will also provide additional information on the life of the composer and the creation of the work. This paper will, in turn, inform future conductors and build a platform for Alec Roth and his music. [1]“Biography,” Biography, Alec Roth, accessed June 16, 2018,http://www.alecroth.com/about/ [2]John Quinn, “Birmingham Dances to Alec Roth’s tune,” Seen and Heard International,September 15, 2012, accessed June 16, 2018. http://seenandheard-international.com/2012/10/birmingham-dances-to-alec-roths-tune

The Soviet Union\u27s Foreign Policy Environment to the

The Soviet Union is, and will remain, a global power. It has used its central geostrategic position on the Eurasian landmass and impressive military capability to intrude a presence into all key regions of the world. Understandably, defense of the homeland and institutionalization of imperial hegemony over Eastern Europe take pride of place in Kremlin calculations

The Changing Strategic Balance and Soviet Third World Risk-Taking

What is the relationship between the changing strategic balance and Soviet risk-taking in the Third World? ls Soviet risk-taking in the Third World likely to increase? If so, under what conditions and for what reasons

Studies of iron impurities in YxPr1-xBa2Cu3O7-delta

Pr is the only rare earth which, when substituted for Y in YBa2Cu3O7, significantly alters the superconducting transition temperature T(sub c) without changing the crystal structure. For YxPr1-xBa2Cu3O7-delta with delta approx. equal to 0, T(sub c) is reduced rapidly as x is increased, reaching zero for x about 0.5. For x above 0.5 the compound is antiferromagnetic with a Neel temperature that increases with increasing x, rising to above room temperature for x near 1. A similar behavior is observed when the oxygen deficit delta is increased from zero to 1 with x=0. For the case of Pr substitution, the drop in T(sub c) is believed due to magnetic interactions. For the case of varying delta with x=0, the drop can be attributed to a combination of magnetic interactions, band filling, and changes in crystal structure. To study these effects, the Mossbauer effect of 57 Fe atoms substituted for the Cu atoms has been observed as a function of delta, x, and temperature. The observed spectra are all well described by a two quadrupole-split pairs, a central singlet, and a six-line magnetic hyperfine field pattern. For several Pr compositions both delta and temperature were varied, and the results support the hypothesis that a magnetic interaction exists between the Fe in the Cu lattice and the substitutional Pr atoms

Microscopic theory for the glass transition in a system without static correlations

We study the orientational dynamics of infinitely thin hard rods of length L, with the centers-of-mass fixed on a simple cubic lattice with lattice constant a.We approximate the influence of the surrounding rods onto dynamics of a pair of rods by introducing an effective rotational diffusion constant D(l),l=L/a. We get D(l) ~ [1-v(l)], where v(l) is given through an integral of a time-dependent torque-torque correlator of an isolated pair of rods. A glass transition occurs at l_c, if v(l_c)=1. We present a variational and a numerically exact evaluation of v(l).Close to l_c the diffusion constant decreases as D(l) ~ (l_c-l)^\gamma, with \gamma=1. Our approach predicts a glass transition in the absence of any static correlations, in contrast to present form of mode coupling theory.Comment: 6 pages, 3 figure

Effect of concentration polarization on permselectivity

In this paper, the variation of permselectivity in the course of concentration polarization is systematically analyzed for a three-layer membrane system consisting of a nonperfectly permselective ion exchange membrane, homogeneous or heterogeneous, flanked by two diffusion layers of a binary univalent electrolyte. For a heterogeneous membrane, an ionic transport model is proposed, which is amenable to analytical treatment. In this model, assuming a constant fixed charge in the membrane and disregarding water splitting, the entire transport problem is reduced to solution of a single algebraic equation for the counterion transport number. It is concluded that for both types of membrane the concentration polarization may significantly affect the permselectivity of the system through the effects of the induced nonuniformity of the coion diffusion flux in the membrane (convexity of the coion concentration profile) and varying membrane-solution interface concentration. While the former is significant for low membrane fixed charge density, for a heterogeneous membrane, the latter might be considerably affected by the flux focusing effect at the permeable membrane segments.United States-Israel Binational Science Foundation (Grant 2010199

End of Life: A Family Narrative

This paper is based on ethnographic research that examines family reaction to an elderly husband and father's end of life. From a group of 30 families in our study (family defined as a widow aged 70 and over and two adult biological children between the ages of 40 and 60), we offer an extreme case example of family bereavement. We report our findings through the open-ended responses of a widow and two children who were interviewed ten months after the death of the husband and father. Three general themes emerged: (1) how the family imputes meaning to the end of life, (2) changes in the roles of family members, and (3) the family's ways of coping with the death, particularly through their belief system. A key finding is that the meaning family members find in their loved one's death is tied to the context of his death (how and where he died), their perception of his quality of life as a whole, and their philosophical, religious, and spiritual beliefs about life, death, and the afterlife that are already in place