Violation of quark-hadron duality and spectral chiral moments in QCD

We analyze the spectral moments of the V-A two-point correlation function. Using all known short-distance constraints and the most recent experimental data from tau decays, we determine the lowest spectral moments, trying to assess the uncertainties associated with the so-called violations of quark-hadron duality. We have generated a large number of 'acceptable' spectral functions, satisfying all conditions, and have used them to extract the wanted hadronic parameters through a careful statistical analysis. We obtain accurate values for the ChPT couplings L10 and C87, and a realistic determination of the dimension six and eight contributions in the operator product expansion, O6=(-5.4^{+3.6}_{-1.6})*10^-3 GeV^6 and O8=(-8.9^{+12.6}_{-7.4})*10^-3 GeV^8, showing that the duality-violation effects have been usually underestimated in previous literature

Testable axion-like particles in the minimal linear σ model

Axion and axion-like particle models are typically affected by a strong fine-tuning problem in conceiving the electroweak and the Peccei-Quinn breaking scales. Within the context of the Minimal Linear σ Model, axion-like particle constructions are identified where this hierarchy problem is solved, accounting for a TeV Peccei-Quinn breaking scale and a pseudoscalar particle with a mass larger than 10 MeV. Potential signatures at colliders and B-factories are discussedThe authors acknowledge partial financial support by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreements No.690575 and No. 674896. J.A.G and L.M. acknowledge partial financial support by the Spanish Agencia Estatal de Investigación (AEI) and the EU Fondo Europeo de Desarrollo Regional(FEDER) through the project FPA2016-78645-P, and through the Centro de excelencia Severo Ochoa Program under grant SEV-2016-0597. L. M. acknowledges partial financial support by the Spanish MINECO through the “Ramón y Cajal” programme (RYC-2015-17173).J.A.G. and L.M. thank the Physics and Astronomy department “Galileo Galilei” of the Padua University for hospitality during the development of this project. Furthermore, L.M. thanks the Kavli Institute for the Physics and Mathematics of the Universe for hospitality during the development of this projec

Estrategias operativas en la resolución de problemas matemáticos en el ciclo medio de la E.G.B.

Este trabajo es el resultado de una investigación sobre cómo los niños realmente resuelven problemas matemáticos. Se han identificado doce estrategias en problemas de naturaleza muy diferente

El sociodrama como técnica de intervención socioeducativa.

Sin resume

El Sistema Antártico

Fil: Gutiérrez Posse, Hortensia D. T.. Universidad de Buenos Aires. Facultad de Derecho. Cátedra Derecho Internacional Público. Buenos Aires, ArgentinaFil: Gutiérrez Posse, Hortensia D. T. Universidad de Buenos Aires. Facultad de Derecho. Cátedra Derecho Internacional Humanitario. Buenos Aires, ArgentinaFil: Alonso, Gabriela Liliana. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, ArgentinaFil: Breier, Ingrid E. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, ArgentinaFil: Cabrera Felisoni, Patricio O. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, ArgentinaFil: González, Ariel W. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, ArgentinaFil: Jorquera, Mario. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, ArgentinaFil: Rizzo Alonso, Hermán G. Universidad de Buenos Aires. Facultad de Derecho. Buenos Aires, ArgentinaEn el marco del ciclo profesional orientado se desarrolló durante 1989 un curso de actualización sobre el sistema antártico. Tenía por objetivo no sólo la profundización de los conocimientos sino también brindar la ocasión de que se ensayasen técnicas de investigación. Los trabajos que a continuación se publican reflejan resultados logrados por alumnos de ese curso. Ellos abordan distintos aspectos de una compleja cuestión que interesa directamente a nuestro país.\n\nPrólogo / Hortensia D. T. Gutiérrez Posse. El Sistema Antártico como régimen objetivo / Gabriela Liliana Alonso. Necesidad de su preservación para salvaguarda de la paz mundial / Ingrid E. Breier. Conservación y protección del medio ambiente antártico / Patricio O. Cabrera Felisoni. Los recursos minerales en el marco del Sistema Antártico : algunas reflexiones / Ariel Walter González. Evolución de los presupuestos jurídicos del Sistema Antártico / Mario Jorquera. Año 1991 y la soberanía en la Antártida, de condición a objetivo / Hernán G. Rizzo Alonso.\

The nuclear and extended mid-infrared emission of Seyfert galaxies

We present subarcsecond resolution mid-infrared (MIR) images obtained with 8-10 m-class ground-based telescopes of a complete volume-limited (DL<40 Mpc) sample of 24 Seyfert galaxies selected from the Swift/BAT nine month catalog. We use those MIR images to study the nuclear and circumnuclear emission of the galaxies. Using different methods to classify the MIR morphologies on scales of ~400 pc, we find that the majority of the galaxies (75-83%) are extended or possibly extended and 17-25% are point-like. This extended emission is compact and it has low surface brightness compared with the nuclear emission, and it represents, on average, ~30% of the total MIR emission of the galaxies in the sample. We find that the galaxies whose circumnuclear MIR emission is dominated by star formation show more extended emission (650+-700 pc) than AGN-dominated systems (300+-100 pc). In general, the galaxies with point-like MIR morphologies are face-on or moderately inclined (b/a~0.4-1.0), and we do not find significant differences between the morphologies of Sy1 and Sy2. We used the nuclear and circumnuclear fluxes to investigate their correlation with different AGN and SF activity indicators. We find that the nuclear MIR emission (the inner ~70 pc) is strongly correlated with the X-ray emission (the harder the X-rays the better the correlation) and with the [O IV] lambda 25.89 micron emission line, indicating that it is AGN-dominated. We find the same results, although with more scatter, for the circumnuclear emission, which indicates that the AGN dominates the MIR emission in the inner ~400 pc of the galaxies, with some contribution from star formation.Comment: 27 pages, 12 figures, accepted by MNRA

Nuestra experiencia con el minivástago femoral de disco a compresión y el cotilo Hedrocel (tantalio)

Durante los años 2000 a 2002 intervinimos 18 pacientes de artrosis o necrosis sintomática de cadera, con minivástago de fijación metafisiaria de Disco a Compresión (Sulzer) y cotilo monobloque de tantalio Hedrocel (Zimmer), con par de fricción alúmina-polietileno. La edad media de los pacientes fue de 46,7 años (rango 35-61), y el seguimiento medio de 42 meses. La valoración clínica se realizó con la escala de Merle D'Augbigné Postel obteniendo 38,8% de resultados excelentes, 22,2 de resultados buenos, 11,1% regulares y 27,4% malos (5 casos). Cuatro casos necesitaron reintervención por aflojamiento del tallo femoral. No hubo ningún fracaso del cotilo. La sustitución protésica de la cadera en los pacientes jóvenes requieren soluciones con la menor resección del hueso, pero este modelo de tallo femoral, no da un resultado satisfactorio, por lo que lo hemos abandonado.Between 2000 2002 we treated 18 patients with symptomatic osteoarthritis or osteonechrosis of hip, with uncemneted Thrust Plate Protesis (Sulzer) and tantalium acetabular componente Hedrocel (Zimmer), with ceramic-pol- yethylene pair. The average age of the patients was 46,7 years (range:35-61), and the average follow-up of 42 months. Clinical evaluation was done with Merle D'Augbigné Postel's scale obtaining 38,8 % of excellent results, 22,2 % of good results, 11,1 % fair and 27,4 % poor (5 cases). Four cases needed re-operation for loosening of the femoral stem. There was no failure of the acetabular component. The hip artrhroplasty in the young patients need solutions with the minor resection of bone, but this model of femoral stem does not give a satisfactory result, therefore we have abandoned it

Validation of active forest fires detected by MSG-SEVIRI by means of MODIS hot spots and AWiFS images.

The detection of forest fires and the determination of their parameters have been usually carried out by polar-orbit sensors: AVHRR, (A)ATSR, BIRD and MODIS mainly. However, their time resolution prevents them from operating in real time. In contrast, the new geostationary sensors have very appropriate capacities for the observation of the Earth and monitoring of forest fires, as is being proved. GOES, MSG and MTSAT are already operative and they have led the international community to think that the global observation network in real time may become a reality. The implementation of this network is the aim of the Global Observations of Forest Cover and Land Cover Dynamics (GOFC/GOLD) FIRE Mapping and Monitoring program, focused internationally on taking decisions concerning the research of the Global Change. In this paper, the operation in real time by the MSG-SEVIRI sensor over the Iberian Peninsula is studied. On the other hand, the reliability of validation results by means of polar sensors, with better spatial resolution, is difficult to analyze due to errors caused by confused location of fires. This paper tries to find the most appropriate spatial scale to carry out comparison between Terra/Aqua-MODIS and Resourcesat1-AWiFS image