Velocity Statistics in Holographic Fluids: Magnetized Quark-Gluon Plasma and Superfluid Flow

We study the velocity statistics distribution of an external heavy particle in holographic fluids. We argue that when the dual supergravity background has a finite temperature horizon the velocity statistics goes generically as $1/v$, compatible with the jet-quenching intuition from the quark-gluon plasma. A careful analysis of the behavior of the classical string whose apparent worldsheet horizon deviates from the background horizon reveals that other regimes are possible. We numerically discuss two cases: the magnetized quark-gluon plasma and a model of superfluid flow. We explore a range of parameters in these top-down supergravity solutions including, respectively, the magnetic field and the superfluid velocity. We determine that the velocity statistics goes largely as $1/v$, however, as we leave the non-relativistic regime we observe some deviations.Comment: 32 pages, 12 figures, references added and minor correction

Selección de planta generadora en la compañía atunera salica del Ecuador s.a.

En el presente trabajo se realizó un estudio técnico para la correcta selección de grupos de generación auxiliar que la compañía pesquera SALICA DEL ECUADOR S.A. debió adquirir para suplir su necesidad de falta de energía debido a los continuos cortes de energía eléctrica de la zona suministrada por la Empresa Eléctrica Peninsular. Se describen la planta industrial, sus instalaciones, sus procesos, su desarrollo y se analiza la situación crítica de cada área de producción y sus requerimientos energéticos con los cuales se pudieron establecer con todas las cargas y se determinó el nivel de potencia necesario que debían tener los equipos de generación. Este estudio se basó en el análisis de factor de coincidencia, producto de la medición de carga de todos los equipos de la planta en su capacidad máxima de funcionamiento, como son los motores, las luces, computadoras, UPS, etc. Se seleccionaron 4 Grupos Electrógenos Caterpillar modelo 3508 DITA de 600 KW c/u, tomando en consideración los siguientes factores tales como: nivel de ruido, sistema de enfriamiento, selección de cargas de todos los motores, etc. Finalmente, se realizó un informe económico, comparativo entre el costo de Kwh. que factura la Empresa Eléctrica “EMEPE” versus el proveído por los grupos electrógenos escogidos, en el cual se concluyó que lo más conveniente era la generación propia, no sólo porque implicaba un ahorro significativo (cerca de US $250,000.oo), sino que también eliminaba la principal deficiencia de la empresa, el mal servicio de EMEPE y la consecuente desventaja provocada por los cortes de energía y sus consecuencias en todos los sistemas de la empresa

Analysis of the p16INK4 and TP53 Tumor Suppressor Genes in Bone Sarcoma Pediatric Patients

Recent data suggest that deletion of p16INK4 and mutation of TP53 are among the most common genetic events in the development of human cancer, since the codified proteins act as brakes of the abnormal cell cycle. As the molecular events leading to the development of pediatric bone sarcomas remain unclear, we analyzed 75 osteosarcoma and Ewing sarcoma samples from 43 pediatric patients to search for alterations at the TP53 or p16INK4 tumor suppressor genes. By means of PCR-DGGE (polymerase chain reaction and denaturing gradient gel electrophoresis) we detected TP53 point mutations in 18.6% of the tumor samples, but no constitutional mutations. In the analysis of p16INK4, 7% of the samples harbored deletions of the gene but no point mutations were detected by SSCP (single strand conformation polymorphism) analysis, just the polymorphism Ala-->Thr at codon 148. These data support the hypothesis that TP53 alterations may play a role in the development of pediatric bone tumors and that the primary mechanism of inactivation of p16INK4 seems to be homozygous deletion rather than point mutation

Dental Treatment under General Anesthesia in Healthy and Medically Compromised/Developmentally Disabled Children: A Comparative Study

Aim: To compare the type, number of procedures and working time of dental treatment provided under dental general anesthesia (DGA) in healthy and medically compromised/developmentally disabled children (MCDD children). Design: This cross-sectional prospective study involved 80 children divided into two groups of 40 children each. Group 1 consisted of healthy and Group 2 consisted of MCDD children. Results: Healthy children needed more working time than MCDD children, the means being 161±7.9 and 84±5.7 minutes, respectively (P= 0.0001). Operative dentistry and endodontic treatments showed a significant statistical difference (P= 0.0001). The means of procedures were 17±5.0 for healthy children and 11±4.8 for MCDD children (P= 0.0001). Conclusions: Healthy children needed more extensive dental treatment than MCDD children under DGA. The information from this sample of Mexican children could be used as reference for determining trends both within a facility as well as in comparing facilities in cross-population studies

El ensayo de micronúcleos como medida de inestabilidad genética inducida por agentes genotóxicos

Human genetic integrity is compromised by the intense industrial activity, which emphasizes the importance to determine an "acceptable" genetic damage level and to carry out routine genotoxicity assays in the populations at risk. Micronuclei are cytoplasmatic bodies of nuclear origin which correspond to genetic material that is not correctly incorporated in the daughter cells in the cellular division; they reflect the existence of chromosomal aberrations and are originated by chromosomal breaks, replication errors followed by cellular division of the DNA and/or exposure to genotoxic agents. There are several factors able to modify the number of micronuclei present in a given cell, among them are age, gender, vitamins, medical treatments, daily exposure to genotoxic agents, etc. The cytogenetic assay for the detection of micronuclei (CBMN: cytokinesis-block micronucleus) is based on the use of a chemical agent, cytochalasin-B, which is able to block cytocinesis but allowing the nuclear division, therefore yielding binucleated and monodivided cells. The micronuclei scoring is performed on 1000 binucleated cells and the starting sample may vary, although most studies are performed on peripheral blood lymphocytes. The micronuclei assay is considered a practical, universally validated and technically feasible protocol which is useful to evaluate the genetic instability induced by genotoxic agent

Caracterización de la cadena productiva de cuyes en el sur de Colombia e identificación de los factores determinantes para la adecuada prestación de servicios de extensión

The development of agrifood systems in Latin America reflects contrasting policy goals. Most governments advocate that “modernization,” measured as increased rates of technology adoption, is the way to address persistent food insecurity. By contrast, peasants’ and indigenous people’s organizations and social movements propose advancing knowledge co-production and co-innovation to increase the resilience of agrifood systems. Colombia reformed the National Innovation System for Agriculture in 2017. The policy reform instructed transitioning from providing “technical advice” to rural extension services. The research aimed to fill the knowledge gap regarding the transition to rural extension along the guinea pig production chain.   In addition to characterizing the production chain, we conducted qualitative and reflectivity analyses to understand better how institutional practices and research cultures hinder or promote transitioning to rural extension. The investigation revealed that small-scale farmers who rely on the production and commercialization of guinea pigs as a livelihood strategy have continued receiving advice to adopt the latest technologies. In closing, besides addressing technological deficits or inefficiencies, a systemic approach that considers cultural context and identity must integrate into rural extension to ensure technological adoption is aligned with the sustainability and resilience objectives of the guinea pig production chain.El desarrollo de los sistemas agroalimentarios en América Latina refleja objetivos de política contrarios. La mayoría de los gobiernos defienden que la “modernización”, medida como mayores tasas de adopción de tecnología, es la forma de abordar la inseguridad alimentaria persistente. Por el contrario, las organizaciones campesinas e indígenas y los movimientos sociales proponen avanzar en la coproducción de conocimiento y la coinnovación para aumentar la resiliencia de los sistemas agroalimentarios. Colombia reformó el Sistema Nacional de Innovación para la Agricultura en 2017, la cual instruyó la transición de prestación del servicio de asistencia técnica al de extensión rural. El propósito de la investigación fue llenar el vacío de conocimiento sobre la transición al extensionismo rural a lo largo de la cadena productiva cuyícola. Además de caracterizar la cadena productiva, se realizaron análisis cualitativos y de reflexividad para comprender mejor la manera en que las prácticas institucionales y las culturas de investigación obstaculizan o promueven la transición hacia la extensión rural. La investigación reveló que los pequeños agricultores quienes dependen de la producción y comercialización de cuyes como estrategia de subsistencia han seguido recibiendo asesoramiento para adoptar las últimas tecnologías. Se concluyó que, además de abordar los déficits o las ineficiencias tecnológicas, se debe integrar un enfoque sistémico que considere el contexto cultural y la identidad al extensionismo rural a fin de garantizar que la adopción tecnológica se ajuste a los objetivos de sostenibilidad y resiliencia de esta cadena productiva

Optical archival spectra of blazar candidates of uncertain type in the 3rd^{rd} Fermi Large Area Telescope Catalog

Despite the fact that blazars constitute the rarest class among active galactic nuclei (AGNs) they are the largest known population of associated $\gamma$-ray sources. Many of the $\gamma$-ray objects listed in the Fermi-Large Area Telescope Third Source catalog (3FGL) are classified as blazar candidates of uncertain type (BCUs), either because they show multifrequency behaviour similar to blazars but lacking optical spectra in the literature, or because the quality of such spectra is too low to confirm their nature. Here we select, out of 585 BCUs in the 3FGL, 42 BCUs which we identify as probable blazars by their WISE infrared colors and which also have optical spectra that are available in the Sloan Digital Sky Survey (SDSS) and/or Six-Degree Field Galaxy Survey Database (6dFGS). We confirm the blazar nature of all of the sources. We furthermore conclude that 28 of them are BL Lacs, 8 are radio-loud quasars with flat radio spectrum and 6 are BL Lac whose emission is dominated by their host galaxy

Refining the associations of the Fermi Large Area Telescope Source Catalogs

The Fermi-Large Area Telescope (LAT) First Source Catalog (1FGL) was released in February 2010 and the Fermi-LAT 2-Year Source Catalog (2FGL) appeared in April 2012, based on data from 24 months of operation. Since their releases, many follow up observations of unidentified gamma-ray sources (UGSs) were performed and new procedures to associate gamma-ray sources with potential counterparts at other wavelengths were developed. Here we review and characterize all the associations as published in the 1FGL and 2FGL catalog on the basis of multifrequency archival observations. In particular we located 177 spectra for the low-energy counterparts that were not listed in the previous Fermi catalogs, and in addition we present new spectroscopic observations of 8 gamma-ray blazar candidates. Based on our investigations, we introduce a new counterpart category of "candidate associations" and propose a refined classification for the candidate low-energy counterparts of the Fermi sources. We compare the 1FGL-assigned counterparts with those listed in the 2FGL to determine which unassociated sources became associated in later releases of the Fermi catalogs. We also search for potential counterparts to all the remaining unassociated Fermi sources. Finally, we prepare a refined and merged list of all the associations of the 1FGL plus 2FGL catalogs that includes 2219 unique Fermi objects. This is the most comprehensive and systematic study of all the associations collected for the gamma-ray sources available to date. We conclude that 80% of the Fermi sources have at least one known plausible gamma-ray emitter within their positional uncertainty regions.Comment: 26 pages, 24 figures, 7 tables, ApJS accepted for publication (pre-proof version uploaded