Bonus scaling and BCFW in N=7 supergravity

In search of natural building blocks for supergravity amplitudes, a tentative criteria is term-by-term bonus z^-2 large momentum scaling. For a given choice of deformation legs, we present such an expansion in the form of a BCFW representation in N=7 supergravity based on a special shift. We will show that this improved scaling behavior, with respect to the fully N=8 representation, is due to its automatic incorporation of the so called bonus relations.Comment: 16 pages, 2 figure

A Continuous Model of Multilateral Bargaining with Random Arrival Times

This paper proposes a continuous-time model framework of bargaining, which is analytically tractable even in complex situations like coalitional bargaining. The main ingredients of the model are: (i) players get to make offers according to a random arrival process; (ii) there is a deadline that ends negotiations. In the case of n-player group bargaining, there is a unique subgame-perfect Nash equilibrium, and the share of the surplus a player can expect is proportional to her arrival rate. In general coalitional bargaining, existence and uniqueness of Markov perfect equilibrium is established. In convex games, the set of limit payoffs as the deadline gets infinitely far away exactly corresponds to the core. The limit allocation selected from the core is determined by the relative arrival rates. As an application of the model, legislative bargaining with deadline is investigated.

The Computational Complexity of Quantum Determinants

In this work, we study the computational complexity of quantum determinants, a $q$-deformation of matrix permanents: Given a complex number $q$ on the unit circle in the complex plane and an $n\times n$ matrix $X$, the $q$-permanent of $X$ is defined as $$\mathrm{Per}_q(X) = \sum_{\sigma\in S_n} q^{\ell(\sigma)}X_{1,\sigma(1)}\ldots X_{n,\sigma(n)},$$ where $\ell(\sigma)$ is the inversion number of permutation $\sigma$ in the symmetric group $S_n$ on $n$ elements. The function family generalizes determinant and permanent, which correspond to the cases $q=-1$ and $q=1$ respectively. For worst-case hardness, by Liouville's approximation theorem and facts from algebraic number theory, we show that for primitive $m$-th root of unity $q$ for odd prime power $m=p^k$, exactly computing $q$-permanent is $\mathsf{Mod}_p\mathsf{P}$-hard. This implies that an efficient algorithm for computing $q$-permanent results in a collapse of the polynomial hierarchy. Next, we show that computing $q$-permanent can be achieved using an oracle that approximates to within a polynomial multiplicative error and a membership oracle for a finite set of algebraic integers. From this, an efficient approximation algorithm would also imply a collapse of the polynomial hierarchy. By random self-reducibility, computing $q$-permanent remains to be hard for a wide range of distributions satisfying a property called the strong autocorrelation property. Specifically, this is proved via a reduction from $1$-permanent to $q$-permanent for $O(1/n^2)$ points $z$ on the unit circle. Since the family of permanent functions shares common algebraic structure, various techniques developed for the hardness of permanent can be generalized to $q$-permanents

In Vitro Efficacy of Combined Macrophage-Mediated Plasmonic Photothermal Therapy and Chemotherapeutic Agents

Although both chemotherapy and hyperthermia therapy have their inherent advantages, the non-specific targeting of chemotherapy and ineffectiveness of hyperthermia therapy alone suggests a better method can be developed. To overcome this problem, the combined treatment of chemotherapeutic agents with plasmonic photothermal therapy (PPTT) is proposed. This is the first study to investigate the efficacy of combined chemotherapy and PPTT using monocytes as delivery vehicles for gold nanoshells. The results of this investigation shows that PPTT combined with cisplatin resulted in some degree of synergism while additive effects were observed for concurrent treatments of PPTT and doxorubicin and PPTT and bleomycin

Coordination-Free Equilibria in Cheap Talk Games

This paper characterizes generic equilibrium play in a multi-sender version of Crawford and Sobel\u27s (1982) cheap talk model, when robustness to a broad class of beliefs about noise in the senders\u27 observation of the state is required. Just like in the one-sender model, information transmission is partial, equilibria have an interval form, and they can be computed through a generalized version of Crawford and Sobels forward solution procedure. Fixing the senders\u27 biases, full revelation is not achievable even as the state space becomes large. Intuitive welfare predictions, such as the desirability of consulting senders with small and opposite biases, follow

The role of initial geometry in experimental models of wound closing

Wound healing assays are commonly used to study how populations of cells, initialised on a two-dimensional surface, act to close an artificial wound space. While real wounds have different shapes, standard wound healing assays often deal with just one simple wound shape, and it is unclear whether varying the wound shape might impact how we interpret results from these experiments. In this work, we describe a new kind of wound healing assay, called a sticker assay, that allows us to examine the role of wound shape in a series of wound healing assays performed with fibroblast cells. In particular, we show how to use the sticker assay to examine wound healing with square, circular and triangular shaped wounds. We take a standard approach and report measurements of the size of the wound as a function of time. This shows that the rate of wound closure depends on the initial wound shape. This result is interesting because the only aspect of the assay that we change is the initial wound shape, and the reason for the different rate of wound closure is unclear. To provide more insight into the experimental observations we describe our results quantitatively by calibrating a mathematical model, describing the relevant transport phenomena, to match our experimental data. Overall, our results suggest that the rates of cell motility and cell proliferation from different initial wound shapes are approximately the same, implying that the differences we observe in the wound closure rate are consistent with a fairly typical mathematical model of wound healing. Our results imply that parameter estimates obtained from an experiment performed with one particular wound shape could be used to describe an experiment performed with a different shape. This fundamental result is important because this assumption is often invoked, but never tested

The contribution of mobile telecommunication technology to sustainable development in selected countries in Africa

Thesis (S.M. in Engineering and Management, and, in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, 2011.Cataloged from PDF version of thesis.Includes bibliographical references (p. 143-150).While most of the world's population resides in countries that are wealthy or developing, the rest reside in low-income and least developed countries (LDCs), left behind and growing more disconnected. At the same time, mobile phones are widely adopted in these underdeveloped areas and demonstrate potential for economic development. However, technological innovation and policies have often addressed narrow dimensions of poverty and development. Sustainable development, on the other hand, assesses the welfare of a country in its entirety. This then begs the question of how mobile telephony technology, given its pervasiveness, can be beneficial on a systemic and sustainable level. This document presents evidence that mobile phones can contribute to sustainable development in several ways. The focus is on selected countries in the sub-Saharan Africa region: Kenya, Tanzania, Uganda, and Nigeria, each of which is categorized as a LDC. The Sustainable Development framework is used to analyze data from case studies and existing technology, institutional and policy trends in the mobile telecommunication industry. The evidence from literature demonstrates that mobile initiatives focused on niche areas, such as banking and health, have benefited on the community level and improved operations within firms. Mobile industry policies have created a healthy system of innovation in these countries. However, environmental development has been secondary or even ignored. Thus, the recommendations focus on prioritizing sustainability, specific policies continuing diffusion and adoption, technology transfer mechanisms, increased robustness in data-tracking and countering external economic shocks. The data presented is not meant to be comprehensive nor complete. Consequently, suggested future work addresses short-term, mid-term, and long-term strategies. Specific areas include examining causal linkages for mobile phone adoption, designing technology initiatives around sustainability goals, and drivers that facilitate technology transfer. Mobile telecommunication technology offers real opportunities for development and growth in Africa. If the focus of development shifts from mere economic growth to sustainable development, countries can not only transform their economic fortunes but also enhance the quality of their environment.by Alexander Shih.S.M.in Engineering and Management, and, in Technology and Polic

Matching, Marriage, and Children: Differences Across Sexual Orientations

There are many differences in behavior across couples of different sexual orientations—some well known, others not. We propose a model which explains differences in expected matching behavior, marriage rates, non-child-friendly activities, and fertility, based on different costs of procreation and complementarities between marriage and children. The model predicts that the biological traits of same-sex couples, unlike those of heterosexual couples, should not be correlated—holding constant other household production characteristics. In addition, the model predicts that heterosexuals have a higher probability of having children and getting married, and that childless heterosexuals are less likely to engage in behaviors not complementary with children than childless gays and lesbians. Using two nationally representative probability samples that self-identify sexual orientation, these predictions are confirmed

Female media use behavior and agreement with publicly promoted agenda-specific health messages.

This study set out to explore the relationship between female media use behavior and agreement with agenda-specific publicly promoted health messages. A random digit dial telephone cross-sectional survey was conducted using a nationally representative sample of female residents aged 25 and over. Respondents' agreement with health messages was measured by a six-item Health Information Scale (HIS). Data were analyzed using chi-square tests and multiple logistic regression. This survey achieved a response rate of 86% (n = 1074). In this study the longest duration of daily television news watching (OR = 2.32), high self-efficacy (OR = 1.56), and greater attention to medical and health news (OR = 5.41) were all correlates of greater agreement with the selected health messages. Surprisingly, Internet use was not significant in the final model. Many women that public health interventions need to be targeting are not receptive to health information that can be accessed through Internet searches. However, they may be more readily targeted by television campaigns. Agenda-specific public health campaigns aiming to empower women to serve as nodes of information transmission and achieve efficient trickle down through the family unit might do better to invest more heavily in television promotion