Gluon energy loss in the gauge-string duality

We estimate the stopping length of an energetic gluon in a thermal plasma of strongly coupled N=4 super-Yang-Mills theory by representing the gluon as a doubled string rising up out of the horizon.Comment: 33 pages, 8 figures. v2: minor improvement

Operator Counting for N=2 Chern-Simons Gauge Theories with Chiral-like Matter Fields

The localization formula of Chern-Simons quiver gauge theory on $S^3$ nicely reproduces the geometric data such as volume of Sasaki-Einstein manifolds in the large-$N$ limit, at least for vector-like models. The validity of chiral-like models is not established yet, due to technical problems in both analytic and numerical approaches. Recently Gulotta, Herzog and Pufu suggested that the counting of chiral operators can be used to find the eigenvalue distribution of quiver matrix models. In this paper we apply this method to some vector-like or chiral-like quiver theories, including the triangular quivers with generic Chern-Simons levels which are dual to in-homogeneous Sasaki-Einstein manifolds $Y^{p,k}(\mathbb{CP}^2)$. The result is consistent with AdS/CFT and the volume formula. We discuss the implication of our analysis.Comment: 23 pages; v2. revised version; v3. corrected typos and clarified argument

Matrix Models for Supersymmetric Chern-Simons Theories with an ADE Classification

We consider N=3 supersymmetric Chern-Simons (CS) theories that contain product U(N) gauge groups and bifundamental matter fields. Using the matrix model of Kapustin, Willett and Yaakov, we examine the Euclidean partition function of these theories on an S^3 in the large N limit. We show that the only such CS theories for which the long range forces between the eigenvalues cancel have quivers which are in one-to-one correspondence with the simply laced affine Dynkin diagrams. As the A_n series was studied in detail before, in this paper we compute the partition function for the D_4 quiver. The D_4 example gives further evidence for a conjecture that the saddle point eigenvalue distribution is determined by the distribution of gauge invariant chiral operators. We also see that the partition function is invariant under a generalized Seiberg duality for CS theories.Comment: 20 pages, 3 figures; v2 refs added; v3 conventions in figure 3 altered, version to appear in JHE

\u201cRelaparoscopic\u201d management of surgical complications: The experience of an Emergency Center

Background/aim: Laparotomy has been the approach of choice for re-operations in patients with surgical complications. The aim of this retrospective analysis was to evaluate the feasibility and the safety of laparoscopic approach for the management of general abdominal surgery complications. Materials and methods: We report a retrospective review of 75 patients who underwent laparoscopic evaluation for postoperative complications over a 4-year period. Primary outcomes (resolution rate by exclusive laparoscopic approach, conversion rate, further surgery rate) and secondary outcomes (mortality, hospitalization, prolonged ileus, wounds problems and median operative time) were evaluated. Results: Sixty-six patients (88 %) were managed with laparoscopic approach without conversion; of these, sixty-three patients (84 %) had no more or further complications and were discharged from hospital between 4 \ub1 3 days after \u201csecond-look\u201d surgery; three patients (4 %) developed postoperative complications requiring a third surgery. Nine cases (12 %) underwent conversion in open surgery after laparoscopic approach. Two elderly patients (2.7 %) died in intensive care unit, because of multi-organ failure syndrome. Median time elapsed between an intervention and another was about 2.5 \ub1 9.5 days. Mean operative time was 90 \ub1 150 min. Postoperative hospital stay was between 4.5 and 18 days. Discussion and conclusion: Laparoscopy has begun to be the preferred method to manage postoperative problems, but only few reports are available actually. Our experience in \u201crelaparoscopic\u201d management of surgical complications seems to suggest that laparoscopy \u201csecond look\u201d is an effective tool after open or laparoscopic surgery for the management of postoperative complications and it may avoid diagnostic delay and further laparotomy and related problems

The ABCDEF's of Matrix Models for Supersymmetric Chern-Simons Theories

We consider N = 3 supersymmetric Chern-Simons gauge theories with product unitary and orthosymplectic groups and bifundamental and fundamental fields. We study the partition functions on an S^3 by using the Kapustin-Willett-Yaakov matrix model. The saddlepoint equations in a large N limit lead to a constraint that the long range forces between the eigenvalues must cancel; the resulting quiver theories are of affine Dynkin type. We introduce a folding/unfolding trick which lets us, at the level of the large N matrix model, (i) map quivers with orthosymplectic groups to those with unitary groups, and (ii) obtain non-simply laced quivers from the corresponding simply laced quivers using a Z_2 outer automorphism. The brane configurations of the quivers are described in string theory and the folding/unfolding is interpreted as the addition/subtraction of orientifold and orbifold planes. We also relate the U(N) quiver theories to the affine ADE quiver matrix models with a Stieltjes-Wigert type potential, and derive the generalized Seiberg duality in 2 + 1 dimensions from Seiberg duality in 3 + 1 dimensions.Comment: 30 pages, 5 figure

Feeding the brain: the importance of nutrients for brain functions and health

\u2018We are what we eat\u2019, said the philosopher Feuerbach. In fact, the quality of the food we eat affects our mind as well: the brain, which represents 2% of our body weight, consumes about 20% of the calories we eat each day. Follow a few rules could therefore help to feed properly our brain, so it works to the best of its ability. It is important to know properties of foods especially regarding their aminoacidic composition because aminoacids are components of neurotransmitters, molecules needed for brain transmission and function. It is also possible to choose specific food to prevent or support different diseases that affects nervous system

The Large N Limit of Toric Chern-Simons Matter Theories and Their Duals

We compute the large N limit of the localized three dimensional free energy of various field theories with known proposed AdS duals. We show that vector-like theories agree with the expected supergravity results, and with the conjectured F-theorem. We also check that the large N free energy is preserved by the three dimensional Seiberg duality for general classes of vector like theories. Then we analyze the behavior of the free energy of chiral-like theories by applying a new proposal. The proposal is based on the restoration of a discrete symmetry on the free energy before the extremization. We apply this procedure at strong coupling in some examples and we discuss the results. We conclude the paper by proposing an alternative geometrical expression for the free energy.Comment: 40 pages, 7 figures, using jheppub.sty, references adde