Some Global Aspects of Duality is String Theory

We explore some of the global aspects of duality transformations in String Theory and Field Theory. We analyze in some detail the equivalence of dual models corresponding to different topologies at the level of the partition function and in terms of the operator correspondence for abelian duality. We analyze the behavior of the cosmological constant under these transformations. We also explore several examples of non-abelian duality where the classical background interpretation can be maintained for the original and the dual theories. In particular we construct a non-abelian dual of $SL(2,R)$ which turns out to be a three-dimensional black holeComment: 31pp. One figure available upon request. CERN-TH-6991/6

Application of optimal control theory to the design of the NASA/JPL 70-meter antenna servos

The application of Linear Quadratic Gaussian (LQG) techniques to the design of the 70-m axis servos is described. Linear quadratic optimal control and Kalman filter theory are reviewed, and model development and verification are discussed. Families of optimal controller and Kalman filter gain vectors were generated by varying weight parameters. Performance specifications were used to select final gain vectors

Single photon events from neutral current interactions at MiniBooNE

The MiniBooNE experiment has reported results from the analysis of $\nu _e$ and $\bar \nu _e$ appearance searches, which show an excess of signal-like events at low reconstructed neutrino energies, with respect to the expected background. A significant component of this background comes from photon emission induced by (anti)neutrino neutral current interactions with nucleons and nuclei. With an improved microscopic model for these reactions, we predict the number and distributions of photon events at the MiniBooNE detector. Our results are compared to the MiniBooNE in situ estimate and to other theoretical approaches. We find that, according to our model, neutral current photon emission from single-nucleon currents is insufficient to explain the events excess observed by MiniBooNE in both neutrino and antineutrino modes.Comment: 10 pages, 8 figures; error analysis improved; accepted in PL

Remarks on Time-Space Noncommutative Field Theories

We propose a physical interpretation of the perturbative breakdown of unitarity in time-like noncommutative field theories in terms of production of tachyonic particles. These particles may be viewed as a remnant of a continuous spectrum of undecoupled closed-string modes. In this way, we give a unified view of the string-theoretical and the field-theoretical no-go arguments against time-like noncommutative theories. We also perform a quantitative study of various locality and causality properties of noncommutative field theories at the quantum level.Comment: 19 pages, LaTe

Impact of the lipid-based nutrient supplements on prevention and treatment of childhood moderate undernutrition

Purpose: This review aims at assessing the effectiveness of LNS interventions for prevention and/or treatment of moderate acute malnutrition (MAM), stunting and other anthropometric indicators for undernutrition in children younger than 5 years. Methodology: Eighteen clinical trials on LNS (soybased or milk-based) supplementation in children were compared with habitual diet/control or corn-soy blend (CSB). Mean changes in height for age (HAZ), weight for age (WAZ) and weight for height z-scores (WHZ) were assessed as primary outcomes. The secondary outcomes included: weight gain, height, mid upper arm circumference (MUAC), recovery from MAM, occurrence of fever, diarrhoea and cough. Findings: The pooled estimate revealed a statistically significant increase in WAZ (weighted mean difference [WMD] =0.09; 95%CI= 0.02, 0.15; p=0.01), WHZ (WMD=0.14; 95%CI= 0.01, 0.26; p=0.000) and improved recovery from MAM (Risk Ratio [RR] = 1.37; 95%CI= 1.14, 1.65; p=0.000) in children receiving LNS compared with control or CBS. No significant effect was observed in HAZ (WMD=0.00;95%CI=-0.02,0.03: p=0.578). Children fed with milk-based LNS (RR=1.68; 95%CI=1.17, 2.39; p=0.005) were more likely to recover significantly from MAM when compared with CSB. Conclusion: Although there is evidence that LNS yield better nutritional outcomes than CSB and control, it is impossible to conclude that the milk-based LNS are superior to soy-based LNS and whether age and duration of intervention significantly affect the effectiveness of LNS on childhood undernutrition. Further research is required before these products can be recommended at scale

Superloop Equations and Two Dimensional Supergravity

We propose a discrete model whose continuum limit reproduces the string susceptibility and the scaling dimensions of $(2,4m)$-minimal superconformal models coupled to $2D$-supergravity. The basic assumption in our presentation is a set of super-Virasoro constraints imposed on the partition function. We recover the Neveu-Schwarz and Ramond sectors of the theory, and we are also able to evaluate all planar loop correlation functions in the continuum limit. We find evidence to identify the integrable hierarchy of non-linear equations describing the double scaling limit as a supersymmetric generalization of KP studied by Rabin.Comment: 34 page