Black Hole Scan

Gravitation theories selected by requiring that they have a unique anti-de Sitter vacuum with a fixed cosmological constant are studied. For a given dimension d, the Lagrangians under consideration are labeled by an integer k=1,2,...,[(d-1)/2]. Black holes for each d and k are found and are used to rank these theories. A minimum possible size for a localized electrically charged source is predicted in the whole set of theories, except General Relativity. It is found that the thermodynamic behavior falls into two classes: If d-2k=1, these solutions resemble the three dimensional black hole, otherwise, their behavior is similar to the Schwarzschild-AdS_4 geometry.Comment: Two columns, revtex, 15 pages, 5 figures, minor typos corrected, final version for Journa

Recovery of Evoked Potentials, Metabolic Activity and Behavior in a Mouse Model of Somatosensory Cortex Lesion: Role of the Neural Cell Adhesion Molecule (NCAM)

Understanding the processes that underlie functional recovery after cortical injury is a major challenge for neurobiology and clinical neurology. The aim of the present study was to establish a mouse model of functional recovery that would facilitate the investigation of the molecular and cellular events involved in cortical dynamics. We show that a focal injury of ∼0.5 mm of diameter and 1 mm depth made in the barrel cortex of adult mice induced a transitory deficit that could be characterized using somatosensory evoked potential (SEP), metabolic mapping and a behavioral test. SEP recordings of short latency responses using an epicranial multi-array system showed a decreased cortical activity in the peri-lesion regions 2 weeks after the injury and a partial recovery to normal pattern 6 weeks after the lesion. Delayed SEP signals over the motor cortex were not altered by the injury. Metabolic mapping with [14C]deoxyglucose uptake in the surround of the injury reproduced the time course of deficit and recovery. Finally, a deficit in vibrissae related performance in a gap-crossing test 1 week after injury was followed by a functional recovery in the following 2 weeks. We show in addition that the recovery process is deficient and significantly delayed in NCAM knockout mice lacking all isoforms of NCAM (neural cell adhesion molecule)and PSA-NCAM. These results support the hypothesis that impairment and recovery of functions after focal cortical lesion involves remodeling of intact circuits surrounding the lesion and that the NCAM molecule participate in this process. The model opens new possibilities for investigating the role of candidate molecules in functional recovery using genetically modified mic

Co-detección de Patógenos Periodontales en Pacientes Chilenos con Periodontitis Crónica

Indexación: ScieloLas enfermedades periodontales asociadas a la placa dental son un importante problema de salud pública. La etiología de estas patologías es de origen multifactorial e involucra factores del hospedero, medio ambiente y de carácter infeccioso asociados a bacterias embebidas en la placa dental. Las principales bacterias asociadas a la periodontitis crónica son Porphyromonas gingivalis, Treponema denticola y Tannerella forsythia, mientras que Aggregatibacter actinomycetemcomitans se ha asociado principalmente a la periodontitis agresiva. Otro microorganismo clave en el desarrollo de la enfermedad es Fusobacterium nucleatum, el cual tiene la capacidad de co-agregarse con los patógenos periodontales y así facilitar su colonización. Para demostrar la prevalencia de estas bacterias, la co-detección y la asociación entre pacientes chilenos fumadores y no fumadores, se analizaron 67 muestras mediante PCR convencional. Los resultados mostraron que un 90% de las muestras fueron positivas para F. nucleatum, siendo la bacteria más detectada. Al analizar la co-detección entre las distintas bacterias se observa que F nucleatum está presente en más de un 80% de los casos cuando se detecta cualquiera de las cuatro bacterias restantes, mientas que A. actinomycetemcomitans se detecta en no más de un 20% al amplificar cualquiera de las bacterias restantes. Por otra parte, los resultados por género indican que existen diferencias significativas en la detección de T. forsythia, F. nucleatum y A. actinomycetemcomitans. Al considerar el factor de tabaquismo se observó que ninguna de las muestras de pacientes fumadores resultó ser positiva para A. actinomycetemcomitans.Periodontal disease associated with dental plaque is a major public health problem. The etiology of these disorders is multifactorial involved seeing host factors, environmental factors and infectious nature associated with the presence of bacteria belonging to the plaque. The main bacteria associated with chronic periodontitis are Porphyromonas gingivalis, Treponema denticola and Tannerella forsythia, while Aggregatibacter actinomycetemcomitans is mainly associated with aggressive periodontitis. Another key organism in the development of the disease is Fusobacterium nucleatum, which has the ability to co-aggregate with other periodontal pathogen. To demonstrate the prevalence of these bacteria and the association between Chilean smokers and nonsmokers patients, 67 samples were analyzed by conventional PCR. The results showed that 90% of the samples were positive for F nucleatum being the most commonly detected bacteria. By analyzing the co-detection between different bacteria shows that F nucleatum is present in more than 80% of cases when it detects any of the four remaining bacteria, which lie A. actinomycetemcomitans was detected in no more than 20% by amplifying any remaining bacteria. Moreover the results by gender indicate that significant differences exist in the detection of T forsythia, F. nucleatum and A. actinomycetemcomitans. In considering the factor of smoking was observed that none of the samples from smokers was found to be positive for A. actinomycetemcomitans.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0719-01072010000300003&nrm=is

ORide: A Privacy-Preserving yet Accountable Ride-Hailing Service

In recent years, ride-hailing services (RHSs) have be- come increasingly popular, serving millions of users per day. Such systems, however, raise significant privacy concerns, because service providers are able to track the precise mobility patterns of all riders and drivers. In this paper, we propose ORide (Oblivious Ride), a privacy- preserving RHS based on somewhat-homomorphic en- cryption with optimizations such as ciphertext packing and transformed processing. With ORide, a service provider can match riders and drivers without learning their identities or location information. ORide offers rid- ers with fairly large anonymity sets (e.g., several thou- sands), even in sparsely populated areas. In addition, ORide supports key RHS features such as easy payment, reputation scores, accountability, and retrieval of lost items. Using real data-sets that consist of millions of rides, we show that the computational and network over- head introduced by ORide is acceptable. For example, ORide adds only several milliseconds to ride-hailing op- erations, and the extra driving distance for a driver is less than 0.5 km in more than 75% of the cases evaluated. In short, we show that a RHS can offer strong privacy guar- antees to both riders and drivers while maintaining the convenience of its services

Structural behavior of cemented bahareque for social housing: A case study in Guayaquil City, Ecuador

The need for social housing creates challenges for engineering. One of the most economical and ecological structural systems for certain areas is the cemented bahareque, which uses Guadua cane, a type of Bamboo with favorable properties for construction. Despite being an ancient technique for the construction of houses, there is not an extensive bibliography that allows making justified decisions regarding their design in most cases. One of the objectives of this article is to present a prototypical design of a housing case with appropriate characteristics to allow a decent occupant’s life with this construction system. For the selected house, the structural behavior is evaluated under gravitational and seismic loads. The constructive criteria that will provide good performance under seismic events are recommended. The most important criteria to follow for the design of wall systems are regularity, continuity, symmetry, bolted connections, rigid diaphragms for mezzanines and continuous maintenance of the Guadua cane elements that make up the framework of the walls. Finally, it is concluded that following the basic criteria of earthquake-resistant design for this type of housing, adequate structural performance can be obtained

Black holes with topologically nontrivial AdS asymptotics

Asymptotically locally AdS black hole geometries of dimension d > 2 are studied for nontrivial topologies of the transverse section. These geometries are static solutions of a set of theories labeled by an integer 0 < k < [(d-1)/2] which possess a unique globally AdS vacuum. The transverse sections of these solutions are d-2 surfaces of constant curvature, allowing for different topological configurations. The thermodynamic analysis of these solutions reveals that the presence of a negative cosmological constant is essential to ensure the existence of stable equilibrium states. In addition, it is shown that these theories are holographically related to [(d-1)/2] different conformal field theories at the boundary.Comment: 13 Pages, 3 figures, two columns, Revtex, last version for PR

Calmodulin regulates transglutaminase 2 cross-linking of Huntingtin

This is the publisher's version, also available electronically from "www.jneurosci.org".Striatal and cortical intranuclear inclusions and cytoplasmic aggregates of mutant huntingtin are prominent neuropathological hallmarks of Huntington's disease (HD). We demonstrated previously that transglutaminase 2 cross-links mutant huntingtin in cells in culture and demonstrated the presence of transglutaminase-catalyzed cross-links in the HD cortex that colocalize with transglutaminase 2 and huntingtin. Because calmodulin regulates transglutaminase activity in erythrocytes, platelets, and the gizzard, we hypothesized that calmodulin increases cross-linking of huntingtin in the HD brain. We found that calmodulin colocalizes at the confocal level with transglutaminase 2 and with huntingtin in HD intranuclear inclusions. Calmodulin coimmunoprecipitates with transglutaminase 2 and huntingtin in cells transfected with myc-tagged N-terminal huntingtin fragments containing 148 polyglutamine repeats (htt-N63-148Q-myc) and transglutaminase 2 but not in cells transfected with myc-tagged N-terminal huntingtin fragments containing 18 polyglutamine repeats. Our previous studies demonstrated that transfection with both htt-N63-148Q-myc and transglutaminase 2 resulted in cross-linking of mutant huntingtin protein fragments and the formation of insoluble high-molecular-weight aggregates of huntingtin protein fragments. Transfection with transglutaminase 2 and htt-N63-148Q-myc followed by treatment of cells with N-(6-aminohexyl)-1-naphthalenesulfonamide, a calmodulin inhibitor, resulted in a decrease in cross-linked huntingtin. Inhibiting the interaction of calmodulin with transglutaminase and huntingtin protein could decrease cross-linking and diminish huntingtin aggregate formation in the HD brain

Generalized BF Theory in Superspace as Underlying Theory of 11D Supergravity

We construct a generalized BF theory in superspace that can embed eleven-dimensional supergravity theory. Our topological BF theory can accommodate all the necessary Bianchi identities for teleparallel superspace supergravity in eleven-dimensions, as the simplest but nontrivial solutions to superfield equations for our superspace action. This indicates that our theory may have solutions other than eleven-dimensional supergravity, accommodating generalized theories of eleven-dimensional supergravity. Therefore our topological theory can be a good candidate for the low energy limit of M-theory, as an underlying fundamental theory providing a `missing link' between eleven-dimensional supergravity and M-theory.Comment: 16 pages, latex, two new paragraphs in section 4 and in Concluding Remarks with two new reference

Sulforaphane rewires central metabolism to support antioxidant response and achieve glucose homeostasis

Cruciferous-rich diets, particularly broccoli, have been associated with reduced risk of developing cancers of various sites, cardiovascular disease and type-2 diabetes. Sulforaphane (SF), a sulfur-containing broccoli-derived metabolite, has been identified as the major bioactive compound mediating these health benefits. Sulforaphane is a potent dietary activator of the transcription factor Nuclear factor erythroid-like 2 (NRF2), the master regulator of antioxidant cell capacity responsible for inducing cytoprotective genes, but its role in glucose homeostasis remains unclear. In this study, we set to test the hypothesis that SF regulates glucose metabolism and ameliorates glucose overload and its resulting oxidative stress by inducing NRF2 in human hepatoma HepG2 cells. HepG2 cells were exposed to varying glucose concentrations: basal (5.5 mM) and high glucose (25 mM), in the presence of physiological concentrations of SF (10 μM). SF upregulated the expression of glutathione (GSH) biosynthetic genes and significantly increased levels of reduced GSH. Labelled glucose and glutamine experiments to measure metabolic fluxes identified that SF increased intracellular utilisation of glycine and glutamate by redirecting the latter away from the TCA cycle and increased the import of cysteine from the media, likely to support glutathione synthesis. Furthermore, SF altered pathways generating NADPH, the necessary cofactor for oxidoreductase reactions, namely pentose phosphate pathway and 1C-metabolism, leading to the redirection of glucose away from glycolysis and towards PPP and of methionine towards methylation substrates. Finally, transcriptomic and targeted metabolomics LC-MS analysis of NRF2-KD HepG2 cells generated using CRISPR-Cas9 genome editing revealed that the above metabolic effects are mediated through NRF2. These results suggest that the antioxidant properties of cruciferous diets are intricately connected to their metabolic benefits