Massive Quark-Gluon Scattering Amplitudes at Tree Level

Results for four-, five-, and six-parton tree amplitudes for massive quark-antiquark scattering with gluons are calculated using the recursion relations of Britto, Cachazo, Feng, and Witten. The required diagrams are generated using shifts of the momenta of a pair of massless legs to complex values. Checks verifying the calculations are described, and a simple formula for the shifted spinors of an internal gluon is presented.Comment: 24 pages, 6 figure

The last shall be first: political dimensions of conditional cash transfers in Brazil

Early evidence suggests that Brazil's Bolsa Família (Family Stipend) program, which currently benefits over 12 million poor families, has alleviated absolute poverty. Although hailed by many as an unqualified success, its political dimensions have been largely ignored or underplayed. These include, for example, the unashamed use of Bolsa Família for electoral purposes, the spread of clientelism and patronage, and the growing dependence of Brazil's poor on income transfers rather than productive employment. Furthermore, there are indications that the popularity of Bolsa Família is encouraging short-termism in social policy. Many Brazilian policy makers now seem to view the program as mainstream social policy rather than as a temporary measure-a perspective that could undermine longer-term investments in key areas such as health and basic education

Extractive Reserves: Building Natural Assets in the Brazilian Amazon

In the Amazon rainforest, Brazil's rubber tappers were the first social group to challenge the predatory development model that is threatening ecological disaster there. Their strategy to set up “extractive reserves”—conservation areas where the local population can harvest non-timber forest products—is examined in “Extractive Reserves: Building Natural Assets in the Brazilian Amazon,” by Anthony Hall.

Experimental Design: Design Experimentation

This paper was selected for publication in MIT’s Design Issues. The research takes an original approach by positioning experimentation as a comprehensive design methodology, rather than using the traditional industrial design approach of employing experimentation as a problem-solving tool within a standard design model. It is an evolution of design thinking on non-linear design methods first developed by Hall and presented to the ‘International Association of Societies of Design Research Conference’, Seoul, South Korea (2009), and in a paper entitled ‘Innovation design engineering: Non-linear progressive education for diverse intakes’ presented at the ‘International Conference on Engineering and Product Design Education’, University of Brighton, UK, which offered a non-linear pedagogy (Hall and Childs 2009) that uniquely supports a diverse interdisciplinary intake. Experimental design is well known in the science domain but very little evidence has been recorded of experimentation in industrial design and its position in relation to work in other science and research domains. Connections are made with theories on research methods, an analysis of case studies and comparisons of literature on experimentation from science disciplines, especially that of Kuhn (1962), Galison (1987), Pasteur’s quadrant for scientific research in Stokes (1997) and Borgdorff (2007). Hall makes significant claims in exploring and articulating a model of design experimentation that highlights the differences between scientific and design experimentation. This work was original in describing an experimental design model for the increasing activity in early phases of design development by recording and enhancing knowledge in this important area for future design research and practice. The methods researched in the paper were later used in experimental design workshops in Daegu, South Korea (2011) and Busan, South Korea (2012)

A Continuous-Time Measurement of the Buy-Sell Pressure in a Limit Order Book Market

In this paper, we investigate the buy and sell arrivl process in a limit order book market. Using an intensity framework allows to estimate the simultaneous buy and sell intensity and to derive a continuous-time measure for the buy-sell pressure in the market. Based on limit order book data from the Australian Stock Exchange (ASX), we show that the buy-sell pressure is particularly influenced by recent market and limit orders and the current depth in the ask and bid queue. We find evidence for the hypothesis that traders use order book information in order to infer from the price setting behavior of market participants. Furthermore, our results indicate that the buy-sell pressure is clearly predictable and is a significant determinant of trade-to-trade returns and volatility.buy and sell arrival process; order book information; market depth; bivariate autoregressive intensity model; buy-sell exces intensity

A Continuous-Time Measurement of the Buy-Sell Pressure in a Limit Order Book Market

In this paper, we investigate the buy and sell arrival process in a limit order book market. Using an intensity framework allows to estimate the simultaneous buy and sell intensity and to derive a continuous-time measure for the buy-sell pressure in the market. Based on limit order book data from the Australian Stock Exchange (ASX), we show that the buy-sell pressure is particularly influenced by recent market and limit orders and the current depth in the ask and bid queue. We find evidence for the hypothesis that traders use order book information in order to infer from the price setting behavior of market participants. Furthermore, our results indicate that the buy-sell pressure is clearly predictable and is a significant determinant of trade-to-trade returns and volatility.buy and sell arrival process; order book information; market depth; bivariate autoregressive intensity model; buy-sell excess intensity

Induction of enzyme activities in tissue slices of Helianthus tuberosus L. tubers

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Supersymmetric Yang-Mills and Supergravity Amplitudes at One Loop

By applying the known expressions for SYM and SUGRA tree amplitudes, we write generating functions for the NNMHV box coefficients of SYM as well as the MHV, NMHV, and NNMHV box coefficients for SUGRA. The all-multiplicity generating functions utilize covariant, on-shell superspace whereby the contribution from arbitrary external states in the supermultiplet can be extracted by Grassmann operators. In support of the relation between dual Wilson loops and SYM scattering amplitudes at weak coupling, the SYM amplitudes are presented in a manifestly dual superconformal form. We introduce ordered box coefficients for calculating SUGRA quadruple cuts and prove that ordered coefficients generate physical cut amplitudes after summing over permutations of the external legs. The ordered box coefficients are produced by sewing ordered subamplitudes, previously used in applying on-shell recursion relations at tree level. We describe our verification of the results against the literature, and a formula for extracting the contributions from external gluons or gravitons to NNMHV superamplitudes is presented.Comment: 46 pages, 2 figures, additional references and clarifications include

Optical measurements on a stabilised linear pinched discharge

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