Probing N=2 superconformal field theories with localization

We use supersymmetric localization to study probes of four dimensional Lagrangian N=2 superconformal field theories. We first derive a unique equation for the eigenvalue density of these theories. We observe that these theories have a Wigner eigenvalue density precisely when they satisfy a necessary condition for having a holographic dual with a sensible higher-derivative expansion. We then compute in the saddle-point approximation the vacuum expectation value of 1/2-BPS circular Wilson loops, and the two-point functions of these Wilson loops with the Lagrangian density and with the stress-energy tensor. This last computation also provides the corresponding Bremsstrahlung functions and entanglement entropies. As expected, whenever a finite fraction of the matter is in the fundamental representation, the results are drastically different from those of N=4 supersymmetric Yang-Mills theory

Influencia de la topografía del fondo sobre la estéreo-agudeza

Human depth perception can be strongly affected by the characteristics of the environment. Previous studies have assessed visual acuity in the frontoparallel plane but little is known about the effect of background topography on stereoacuity. In the present experiment, based on alignment tasks, we analyzed how stimulus orientation and 3D background configuration influence stereoscopic vision. An experiment was designed to investigate the influence of stimulus orientation (0, 45 and 90 degrees) and background configuration (flat, black, concave and convex) on precision in 3D visual alignment tasks in a virtual environment. Background was found to result in an underestimation of stereoacuity, with the highest and lowest precision scores in comparison judgment tasks corresponding to convex and concave backgrounds, respectively. In addition, a significant orientation by background interaction was discovered. We conclude that background local depth cues are integrated with our target stimuli to contribute to depth perceptionLas características del medio pueden influir notablemente en la percepción de la profundidad en humanos. Estudios previos han evaluado la agudeza visual en el plano fronto-paralelo sin embargo, desconocemos cómo la topografía de fondo, contra el que se muestra el estímulo, afecta a la agudeza estereoscópica. Hemos diseñado un experimento, en el que aplicamos a los sujetos una tarea de alineación visual, a partir de esta, examinamos cómo la orientación del estímulo y el tipo de relieve de una superficie 3D usada como configuración de fondo, altera la agudeza estereoscópica. Mediante el método de estímulos constantes, investigamos la influencia de la orientación del estímulo (grados 0, 45 y 90) y la configuración de fondo (plano convexo, negro, y cóncava) sobre la precisión en los juicios de alineación visual 3D en un entorno virtual. Los resultados mostraron que el fondo provocaba cierta tendencia a la subestimación de la estéreo-agudeza, obteniéndose las puntuaciones máximas y mínimas, en cuanto a precisión, en los juicios correspondientes a los fondos convexo y cóncavo, respectivamente. Además, el análisis estadístico reveló una interacción significativa entre "orientación x fondo". Concluimos que las claves locales de profundidad de la superficie de fondo se integran con los estímulos que debían alinearse para contribuir a la percepción de profundidad

Influencia de la topografía del fondo sobre la estéreo-agudeza

Human depth perception can be strongly affected by the characteristics of the environment. Previous studies have assessed visual acuity in the frontoparallel plane but little is known about the effect of background topography on stereoacuity. In the present experiment, based on alignment tasks, we analyzed how stimulus orientation and 3D background configuration influence stereoscopic vision. An experiment was designed to investigate the influence of stimulus orientation (0, 45 and 90 degrees) and background configuration (flat, black, concave and convex) on precision in 3D visual alignment tasks in a virtual environment. Background was found to result in an underestimation of stereoacuity, with the highest and lowest precision scores in comparison judgment tasks corresponding to convex and concave backgrounds, respectively. In addition, a significant orientation by background interaction was discovered. We conclude that background local depth cues are integrated with our target stimuli to contribute to depth perceptionLas características del medio pueden influir notablemente en la percepción de la profundidad en humanos. Estudios previos han evaluado la agudeza visual en el plano fronto-paralelo sin embargo, desconocemos cómo la topografía de fondo, contra el que se muestra el estímulo, afecta a la agudeza estereoscópica. Hemos diseñado un experimento, en el que aplicamos a los sujetos una tarea de alineación visual, a partir de esta, examinamos cómo la orientación del estímulo y el tipo de relieve de una superficie 3D usada como configuración de fondo, altera la agudeza estereoscópica. Mediante el método de estímulos constantes, investigamos la influencia de la orientación del estímulo (grados 0, 45 y 90) y la configuración de fondo (plano convexo, negro, y cóncava) sobre la precisión en los juicios de alineación visual 3D en un entorno virtual. Los resultados mostraron que el fondo provocaba cierta tendencia a la subestimación de la estéreo-agudeza, obteniéndose las puntuaciones máximas y mínimas, en cuanto a precisión, en los juicios correspondientes a los fondos convexo y cóncavo, respectivamente. Además, el análisis estadístico reveló una interacción significativa entre "orientación x fondo". Concluimos que las claves locales de profundidad de la superficie de fondo se integran con los estímulos que debían alinearse para contribuir a la percepción de profundidad

The influence of background topography on stereo-acuity

Human depth perception can be strongly affected by the characteristics of the environment. Previous studies have assessed visual acuity in the frontoparallel plane but little is known about the effect of background topography on stereoacuity. In the present experiment, based on alignment tasks, we analyzed how stimulus orientation and 3D background configuration influence stereoscopic vision. An experiment was designed to investigate the influence of stimulus orientation (0, 45 and 90 degrees) and background configuration (flat, black, concave and convex) on precision in 3D visual alignment tasks in a virtual environment. Background was found to result in an underestimation of stereoacuity, with the highest and lowest precision scores in comparison judgment tasks corresponding to convex and concave backgrounds, respectively. In addition, a significant orientation by background interaction was discovered. We conclude that background local depth cues are integrated with our target stimuli to contribute to depth perceptio

New evidence of visual space anisotropy with autostereograms

Postprint (published version

First-in-human PeriCord cardiac bioimplant : scalability and GMP manufacturing of an allogeneic engineered tissue graft

Altres ajuts: La Marató de TV3 Foundation, Government of Catalonia, Catalan Society of Cardiology, "La Caixa" Banking Foundation, Spanish Ministry of Science, Innovation and Universities, Institute of Health Carlos III, and the European Regional Development Fund.Small cardiac tissue engineering constructs show promise for limiting post-infarct sequelae in animal models. This study sought to scale-up a 2-cm 2 preclinical construct into a human-size advanced therapy medicinal product (ATMP; PeriCord), and to test it in a first-in-human implantation. The PeriCord is a clinical-size (12-16 cm 2) decellularised pericardial matrix colonised with human viable Wharton's jelly-derived mesenchymal stromal cells (WJ-MSCs). WJ-MSCs expanded following good manufacturing practices (GMP) met safety and quality standards regarding the number of cumulative population doublings, genomic stability, and sterility. Human decellularised pericardial scaffolds were tested for DNA content, matrix stiffness, pore size, and absence of microbiological growth. PeriCord implantation was surgically performed on a large non-revascularisable scar in the inferior wall of a 63-year-old male patient. Coronary artery bypass grafting was concomitantly performed in the non-infarcted area. At implantation, the 16-cm 2 pericardial scaffold contained 12·5 × 10 6 viable WJ-MSCs (85·4% cell viability; <0·51 endotoxin units (EU)/mL). Intraoperative PeriCord delivery was expeditious, and secured with surgical glue. The post-operative course showed non-adverse reaction to the PeriCord, without requiring host immunosuppression. The three-month clinical follow-up was uneventful, and three-month cardiac magnetic resonance imaging showed ~9% reduction in scar mass in the treated area. This preliminary report describes the development of a scalable clinical-size allogeneic PeriCord cardiac bioimplant, and its first-in-human implantation. La Marató de TV3 Foundation, Government of Catalonia, Catalan Society of Cardiology, "La Caixa" Banking Foundation, Spanish Ministry of Science, Innovation and Universities, Institute of Health Carlos III, and the European Regional Development Fund

New insights into holography from supersymmetric localization

[eng] Maldacena's conjecture, often known as the holographic duality or the AdS/CFT correspondence, proposes an equivalence between gravitational theories in a hyperbolic space of a certain dimensionality and gauge theories living on its boundary. The manner in which this connection is established makes the duality specially remarkable: both sides are thought to describe the very same string theoretic physics, but the validity regimes of the two descriptions are disjoint, and one expects either framework to be in its regime of validity the appropriate way to effectively reexpress the physics of the other. The nonintersection of these applicability regimes makes the duality very useful, but also very hard to verify and materialize. Notice the potential implications of this framework for theoretical physics: one direction, strongly coupled quantum field theories become in a certain regime describable as semiclassical gravitational spacetimes, while on the other direction certain string theories without semiclassical background obtain a clean and workable definition as gauge field theories. As a consequence of these facts, holography has played a central role in research since its appearance, almost two decades ago. However, despite numerous efforts devoted to its characterization, general understanding of the duality has only been majoritarely achieved around the regimes where the gravitational description becomes semiclassical. Consequently, the gauge-to-gravity direction of the duality is far less exploited than the opposite one, despite its conceptual relevance. Having available results for strongly coupled gauge theories would be of a great help in addressing holography in this comparatively underdevelopped direction, and they would set a fertile ground to test, refine and understand the holographic conjecture. These type of predictions are hard to come by, but not inexistent: non-renormalized magnitudes constitute their most paradygmatical example, and recently different techniques have obtained exact results at arbitrary coupling for specific obserable sectors. This thesis studies specifically one of these techniques, known as supersymmetric localization, and its role in shoring AdS/CFT. In particular, it restricts its analysis to a specific type of theory: Lagrangian N. = 2 SYM, and for specific results: half-BPS Wilson circular loops. Several interesting insights are put forward by its results. A first observation is that the exact functional dependence we obtain from localization offer a guide on how to extend holographic predictions from their validity regime to a finite gauge range which produces plausible results, although a great care has to be taken in this process. Complementarily, the study of this parametrical dependence for gauge N. = 4 theories with gauge Lie algebras presents two suggestive patterns: On the one hand, 't Hooft's topological expansion presents, at least for charges in fundamental representations, an underlying structure that relates sectors with different number of crosscaps among themselves. On the other hand, the matrix model structure obtained in the localization process can be interpreted in terms of a fermionic quantum mechanics, which at the 't Hooft limit matches the "bubbling geometry" structure of Lin, Lunin and Maldacena, but which persists at finite gauge group range. Finally, the comparison of localization results within a more general type of construction is pre-sented. The specific set of theories considered contains both examples with semiclassical holographic duals and examples where this type of geometry is precluded. Supersymmetric field predictions in this case differentiate both groups with qualitatively different behaviours in the matrix model. This suggests a possible connection between the matrix model structure and the semiclassical spacetime codification in the dual field theory. Similar observations have been made in the literature. This thesis, therefore, explicits a wide list of suggestions for holography that are motivated by lo-calization results in different regimes, even though the latter have been severely restricted to particular examples.[cat] Aquesta tesi estudia les lliçons que hom pot extreure, des del punt de vista de la dualitat hologràfica, de l'anomenada localització supersimètrica. La conjunció d'aquests dos formalismes ha estat utilitzada anteriorment per verificar els resultats del primer, però aquesta tesi va un pas més enllà i qüestiona fins a quin punt els resultats exactes oferts per la localització poden ser útils per extendre l'aplicabilitat de l'holografia gravitatòria. L'anàlisi d'aquests resultats en diferents règims posa de relleu diversos aspectes d'interès. Una primera observació és que la dependència funcional exacta que hom pot llegir dels resultats de la localització ofereixen, quan són utilitzats amb cura, una guia per estendre les prediccions holgràfiques des del seu règim de validesa a un rang de gauge finit mitjançant la qual es pot obtenir resultats plausibles. Complementàriament, l'estudi d'aquesta dependència paramètrica per teories maximalment super-simètriques amb grups de Lie clàssics presenta dos patrons suggerents: d'una banda, el desenvolupa-ment de 't Hooft té, almenys per càrregues en representació fonamental, una estructura subjacent que relaciona els sectors amb diferent nombre d'inversions topològiques entre ells. De l'altra, l'estructura dels models de matrius obtinguts en localitzar pot ésser interpretada en termes d'una mecànica quàntica de fermions, que encaixa amb l'estructura dels "universos de bombolles" de Lin, Lunin i Maldacena al límit de 't Hooft, però que manté la seva forma a qualsevol rang finit. Per últim, es compara resultats de localització entre ells en un marc de teories més generals, en què algunes admeten dual semiclàssic i d'altres no és d'esperar que ho facin. Les prediccions supersimètriques en aquest cas presenten diferències qualitatives que permeten distingir aquests dos grups de teories, suggerint una possible connexió entre la codificació de l'estructura gravitatòria a la teoria de camps i el model de matrius que s'obté en localitzar que complementa altres indicis en el mateix sentit obtinguts a la literatura. En definitiva, doncs, es posa de manifest en aquesta tesi que, tot i haver restringit l'anàlisi a sectors i observables específics, els resultats obtinguts per mitjà de la localització supersimètrica ofereixen una rica gamma de suggeriments sobre l'estructura hologràfica