The Flow Fingerprinting Game

Linking two network flows that have the same source is essential in intrusion detection or in tracing anonymous connections. To improve the performance of this process, the flow can be modified (fingerprinted) to make it more distinguishable. However, an adversary located in the middle can modify the flow to impair the correlation by delaying the packets or introducing dummy traffic. We introduce a game-theoretic framework for this problem, that is used to derive the Nash Equilibrium. As obtaining the optimal adversary delays distribution is intractable, some approximations are done. We study the concrete example where these delays follow a truncated Gaussian distribution. We also compare the optimal strategies with other fingerprinting schemes. The results are useful for understanding the limits of flow correlation based on packet timings under an active attacker.Comment: Workshop on Information Forensics and Securit

Assessing the Psychedelic "After-Glow" in Ayahuasca Users : Post-Acute Neurometabolic and Functional Connectivity Changes Are Associated with Enhanced Mindfulness Capacities

Ayahuasca is a plant tea containing the psychedelic 5-HT agonist N,N -dimethyltryptamine and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network, purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here, we investigated in an open-label uncontrolled study in 16 healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications and their association with mindfulness measures. Using 1 H-magnetic resonance spectroscopy and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior and anterior cingulate cortex after a single ayahuasca dose. Magnetic resonance spectroscopy showed post-acute reductions in glutamate+glutamine, creatine, and N-acetylaspartate+N-acetylaspartylglutamate in the posterior cingulate cortex. Connectivity was increased between the posterior cingulate cortex and the anterior cingulate cortex, and between the anterior cingulate cortex and limbic structures in the right medial temporal lobe. Glutamate+glutamine reductions correlated with increases in the "nonjudging" subscale of the Five Facets Mindfulness Questionnaire. Increased anterior cingulate cortex-medial temporal lobe connectivity correlated with increased scores on the self-compassion questionnaire. Post-acute neural changes predicted sustained elevations in nonjudging 2 months later. These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the posterior cingulate cortex, a key region within the default mode network, and increased connectivity between the anterior cingulate cortex and medial temporal lobe structures involved in emotion and memory potentially underlie the post-acute psychological effects of ayahuasca

Variables de interacción entre iguales y resolución de problemas

Contrastar la incidencia de algunas variables de índole relaciónal (como la amistad), en la interacción entre compañeros durante una sesión de entrenamiento en resolución de problemas y en los previsibles progresos subsiguientes de la misma. 96 sujetos de 7 años, pertenecientes a 4 colegios de EGB. De Valladolid capital (dos públicos y dos privados concertados). Investigación con dos fases: teórica y empírica; basada fundamentalmente en los trabajos de la Psicología social genética o evolutiva. Diseño de pretest-entrenamiento-posttest, los alumnos proceden de dos medios socioculturales diferentes, distribuidos en un grupo control y 4 experimentales en función de las variables independientes: medio social; agrupación para la tarea. Se tuvo en cuenta: edad, sexo, habilidad individual y relaciones de amistad. Variable dependiente: resultados en rompecabezas impresos, mejoras pre-posttest en los cubos de Kohs. Se comprueba la existencia de interacción entre medio social y agrupación y, por otro lado, la clara incidencia del factor interacción entre compañeros durante la tarea de entrenamiento. Se observa también que en las diadas formadas por grupos de amigos y los de imagen positiva se dan con más frecuencia conductas interactivas y en ellas se da el mayor índice de progreso.Castilla y LeónBiblioteca de Educación del Ministerio de Educación, Cultura y Deporte; Calle San Agustín, 5 - 3 Planta; 28014 Madrid; Tel. +34917748000; Fax +34917748026; [email protected]

Assessing the Psychedelic "After-Glow" in Ayahuasca Users : Post-Acute Neurometabolic and Functional Connectivity Changes Are Associated with Enhanced Mindfulness Capacities

Ayahuasca is a plant tea containing the psychedelic 5-HT agonist N,N -dimethyltryptamine and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network, purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here, we investigated in an open-label uncontrolled study in 16 healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications and their association with mindfulness measures. Using 1 H-magnetic resonance spectroscopy and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior and anterior cingulate cortex after a single ayahuasca dose. Magnetic resonance spectroscopy showed post-acute reductions in glutamate+glutamine, creatine, and N-acetylaspartate+N-acetylaspartylglutamate in the posterior cingulate cortex. Connectivity was increased between the posterior cingulate cortex and the anterior cingulate cortex, and between the anterior cingulate cortex and limbic structures in the right medial temporal lobe. Glutamate+glutamine reductions correlated with increases in the "nonjudging" subscale of the Five Facets Mindfulness Questionnaire. Increased anterior cingulate cortex-medial temporal lobe connectivity correlated with increased scores on the self-compassion questionnaire. Post-acute neural changes predicted sustained elevations in nonjudging 2 months later. These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the posterior cingulate cortex, a key region within the default mode network, and increased connectivity between the anterior cingulate cortex and medial temporal lobe structures involved in emotion and memory potentially underlie the post-acute psychological effects of ayahuasca

Adiponectin and Leptin Induce VCAM-1 Expression in Human and Murine Chondrocytes

BACKGROUND: Osteoarthritis (OA) and rheumatoid arthritis (RA), the most common rheumatic diseases, are characterized by irreversible degeneration of the joint tissues. There are several factors involved in the pathogenesis of these diseases including pro-inflammatory cytokines, adipokines and adhesion molecules. OBJECTIVE: Up to now, the relationship between adipokines and adhesion molecules at cartilage level was not explored. Thus, the aim of this article was to study the effect of leptin and adiponectin on the expression of VCAM-1 in human and murine chondrocytes. For completeness, intracellular signal transduction pathway was also explored. METHODS: VCAM-1 expression was assessed by quantitative RT-PCR and western blot analysis upon treatment with leptin, adiponectin and other pertinent reagents in cultured human primary chondrocytes. Signal transduction pathways have been explored by using specific pharmacological inhibitors in the adipokine-stimulated human primary chondrocytes and ATDC5 murine chondrocyte cell line. RESULTS: Herein, we demonstrate, for the first time, that leptin and adiponectin increase VCAM-1 expression in human and murine chondrocytes. In addition, both adipokines have additive effect with IL-1β. Finally, we demonstrate that several kinases, including JAK2, PI3K and AMPK are at a play in the intracellular signalling of VCAM-1 induction. CONCLUSIONS: Taken together, our results suggest that leptin and adiponectin could perpetuate cartilage-degrading processes by inducing also factors responsible of leukocyte and monocyte infiltration at inflamed joints