Evaluación del diámetro y la conicidad de los instrumentos ProFile

El objetivo del trabajo fue comprobar la correspondencia de los instrumentos endodóncicos ProFile .04/.06 con la denominación de su calibre apical según las normas ISO con la citada normativa. Para ello se tomaron un total de setenta y dos instrumentos ProFile ISO de 21 mm de los diámetros 15 al 40 y de conicidad .04 y .06. Se utilizó un microscopio óptico de medida para la determinación del diámetro d2 y d3 para realizar el cálculo de d1 y de la conicidad. Los instrumentos testados reunían las dimensiones de extremo apical características de los ProFile Series 29 en sus calibres del 15 al 35, mientras que sólo se ajustaban a la normativa ISO los tamaños 15, 35 y 40. Respecto a la conicidad, todos los especímenes se encontraban dentro de los valores establecidos por la normativa ISO

A new method to study energy-dependent arrival delays on photons from astrophysical sources

Correlations between the arrival time and the energy of photons emitted in outbursts of astrophysical objects are predicted in quantum and classical gravity scenarios and can appear as well as a result of complex acceleration mechanisms responsible for the photon emission at the source. This paper presents a robust method to study such correlations that overcomes some limitations encountered in previous analysis, and is based on a Likelihood function built from the physical picture assumed for the emission, propagation and detection of the photons. The results of the application of this method to a flare of Markarian 501 observed by the MAGIC telescope are presented. The method is also applied to a simulated dataset based on the flare of PKS 2155-304 recorded by the H.E.S.S. observatory to proof its applicability to complex photon arrival time distributions.Comment: 18 pages, 7 figure

Assessment of 3D Printing Technologies for Millimeter Wave Reflectors

Three different 3D printing technologies: Stereolithography (SLA), Fused Deposition Modeling (FDM) and HP Multi Jet Fusion Technology (MJF) are compared to build a parabolic reflector operating at 100 GHz. Fabrication tolerance and surface roughness before and after metallization are accurately measured. The performance of the reflectors is measured in the near field and its performance is compared against an optical grade reflector. In this way the performance of the final product is thoroughly assesse

Writing Sociology at University

User guide to written communication in academic disciplines (in this case sociology) for teachers and students

Lorentz Symmetry breaking studies with photons from astrophysical observations

Lorentz Invariance Violation (LIV) may be a good observational window on Quantum Gravity physics. Within last few years, all major Gamma-ray experiments have published results from the search for LIV with variable astrophysical sources: gamma-ray bursts with detectors on-board satellites and Active Galactic Nuclei with ground-based experiments. In this paper, the recent time-of-flight studies with unpolarized photons published from the space and ground based observations are reviewed. Various methods used in the time delay searches are described, and their performance discussed. Since no significant time-lag value was found within experimental precision of the measurements, the present results consist of 95% confidence cevel limits on the Quantum Gravity scale on the linear and quadratic terms in the standard photon dispersion relations.Comment: 22 pages, 9 figures. V2 match the published version. Invited review talk to the 2nd International Colloquium "Scientific and Fundamental Aspects of the Galileo Programme", 14-16 october 2009, Padua, Ital

From childhood financial hardship to late-life depression: socioeconomic pathways

Objective: Childhood financial hardship is associated with depression throughout the life course, including older adulthood. However, it is still unclear the extent to which occupation, education level and household income are mediators of this association. We aimed to examine the association between childhood financial hardship and late-life depression, and potential socioeconomic mediators using community-based data. Methods: A nationally representative sample of 3623 non-institutionalized older Spanish adults aged 50+ was used. The associations between childhood financial hardship and depression, socioeconomic mediator variables and confounding variables such as chronic physical conditions, number of close people, and loneliness, were assessed through logistic regression models. Mediation analyses of socioeconomic variables were carried out. Results: Older Spanish adults who experienced a poor childhood financial situation were nine times more likely to obtain a lower level of education than those with a good childhood financial situation, and about three times more likely to suffer from depression. Participants' education level mediated about 35-40% of the association between childhood financial hardship and late-life depression whereas we found no significant mediation effect of household income and occupation skill. Conclusion: Improving access to the educational system during the life course might result in a reduction in the prevalence of depression in the general population of older adults and particularly among individuals with low socioeconomic status

Lens based switched beam antenna for a 5G smart repeater

A 16 switched beam lens based antenna with a coverage area of ±30° in the horizontal plane and from 0 to -20° in the vertical plane has been built and tested. The intended use of the antenna is as part of a smart repeater servicing the coverage area of a 5G wireless communication system operating in the n258 band of the 5G Frequency Range 2, from 24.25 to 27.5 GHz. The antenna has been built using state-of-the-art materials and components in order to assess the performance of this antenna concept. The overall antenna losses including the feeding network are of the order of 8 dB and the realized gain in the 80% of the coverage area is above 11 dB.This work was funded in part by AEI: PID2019-107885GB-C31/AEI/10.13039/501100011033 and HUAWEI TECHNOLOGIES Italia S.r.lPeer ReviewedPostprint (author's final draft

Resistencia a la fractura de premolares superiores reconstruidos

Resistencia a la fractura experimental de premolares superiores tratados endodóncicamente y restau­rados, utilizando tres métodos diferentes de reconstrucción. Los dientes fueron agrupados según el método de reconstrucción, montados en una prensa hidráulica y las cúspides sometidas a una fuerza compresiva, hasta el momento de la fractura. Se comparan las fuerzas de fractura de los diferentes grupos

Disseny d'itineraris d'educació ambiental en ambients de fons de vall

L'anàlisi de l'estat actual dels equipaments i activitats d'educació ambiental (EA) en l'àmbit del Parc Natural de l'Alt Pirineu (PNAP) ha detectat un grau de desenvolupament molt baix d'aquesta disciplina. Per aquest motiu, s'elabora una nova eina, amb l'objectiu d'establir unes pautes per a l'elaboració d'una activitat d'EA concreta: els itineraris d'EA; i així ampliar l'escassa oferta actual. El protocol per al disseny d'itineraris d'EA, dóna unes directrius per a estandarditzar la descripció i l'anàlisi de la zona proposada. La finalitat del qual és facilitar i agilitar la implantació d'itineraris que presentin unes condicions mínimes establertes. La eficiència d'aquesta eina, queda verificada amb els resultats obtinguts en la realització de dues proves pilot en dues zones amb possibilitats de desenvolupar-hi itineraris d'EA. Una de les zones ha quedat descartada, per l'incompliment d'un dels criteris que s'ha definit en el protocol com a imprescindibles pel bon desenvolupament de l'activitat que es planteja. Mentre que en l'altre zona, el compliment de totes aquestes condicions o criteris, fan viable la implantació de l'itinerari d'EA, duent a terme així el seu posterior disseny. Malgrat l'estudi es centri en un espai natural protegit concret, és una eina que pretén ser extrapolable en d'altres espais d'aquesta categoria.El análisis del estado actual de los equipamientos y actividades d'educación ambiental (EA) en el ámbito del Parque Natural del Alto Pirineo (PNAP) ha detectado un grado de desarrollo muy bajo de la disciplina. Por esta razón, se elabora una nueva herramienta, con el objetivo de establecer unas pautas para la elaboración de una actividad de EA determinada: los itinerarios de EA; y así ampliar la escasa oferta actual. El protocolo para el diseño de itinerarios de EA, marca unas directrices para estandarizar la descripción y el análisis de la zona propuesta. Su finalidad es facilitar y agilizar la implantación de itinerarios que presenten unas mínimas condiciones establecidas. La eficiencia de la herramienta se verifica mediante los resultados conseguidos en la realización de dos pruebas piloto en dos zonas con posibilidades de desarrollo de itinerarios de EA. Una de las zonas queda descartada, por el incumplimiento de uno de los criterios que se define en el protocolo como imprescindible por el buen desarrollo de la actividad que se plantea. Mientras que en la otra zona, el cumplimiento de todas estas condiciones o criterios, hacen viable la implantación del itinerario de EA, realizando así su posterior diseño. Aunque el estudio se localice en un espacio natural protegido (ENP) concreto, es una herramienta que pretende ser extrapolable en otros espacios de esta categoría.An analysis of the current state of the facilities and activities for environmental education (EE) in within the High Pyrinees Natural Park (HPNP) has found a very low level of development in this field. Because of the above mentioned, a new tool has been developed, with the purpose of establishing a set of procedures aimed at the development of a specific activity in the field of EE: EE routes; so as to increase the now insufficient number on offer. This protocol for the design of routes interesting from an EE point of view, gives a set of directives so as to create a standard in the description and analysis of the given area. The aim of this protocol is to help in the creation of routes that contain a group of previously established minimum requirements. The efficiency of this tool is proved by the results achieved in two preliminary tests in two areas in which it is conceivable that such routes (EE) might be established. One of these areas has been discarded due to it failing to meet one of the guidelines defined in the protocol as essential in the development of the activity here being examined. On the other hand, the other area meets all the requirements, and is viable for the establishment of an EE route. Even though the survey focuses only on one protected natural area, it is a tool designed to be used in other similar areas