Energetics of intrinsic point defects in ZrSiO4_4

Using first principles calculations we have studied the formation energies, electron and hole affinities, and electronic levels of intrinsic point defects in zircon. The atomic structures of charged interstitials, vacancies, Frenkel pairs and anti-site defects are obtained. The limit of high concentration of point defects, relevant for the use of this material in nuclear waste immobilization, was studied with a variable lattice relaxation that can simulate the swelling induced by radiation damage. The limit of low concentration of defects is simulated with larger cells and fixed lattice parameters. Using known band offset values at the interface of zircon with silicon, we analyze the foreseeable effect of the defects on the electronic properties of zircon used as gate in metal-oxide-semiconductor devices.Comment: preprint 16 pages, 4 figures, and 5 table

Lifetimes of ultralong-range strontium Rydberg molecules in a dense BEC

The lifetimes and decay channels of ultralong-range Rydberg molecules created in a dense BEC are examined by monitoring the time evolution of the Rydberg population using field ionization. Studies of molecules with values of principal quantum number, $n$, in the range $n=49$ to $n=72$ that contain tens to hundreds of ground state atoms within the Rydberg electron orbit show that their presence leads to marked changes in the field ionization characteristics. The Rydberg molecules have lifetimes of $\sim1-5\,\mu$s, their destruction being attributed to two main processes: formation of Sr$^+_2$ ions through associative ionization, and dissociation induced through $L$-changing collisions. The observed loss rates are consistent with a reaction model that emphasizes the interaction between the Rydberg core ion and its nearest neighbor ground-state atom. The measured lifetimes place strict limits on the time scales over which studies involving Rydberg species in cold, dense atomic gases can be undertaken and limit the coherence times for such measurements.Comment: 9 pages, 8 figure

Experimental evaluation of the injection force exerted in intraocular lens delivery with syringe-type injectors

The process of intraocular lens (IOL) delivery within the capsular bag during cataract surgery is crucial, as the integrity of the IOL, the injector and the ocular structures should be preserved at all times. This study aims to obtain the main parameters that affect the injection force exerted in the ejection of an intraocular lens (IOL) through syringe-type injectors. For that purpose, ejection tests were carried out in vitro, measuring the resistance force throughout the entire delivery process. The effect of IOL material, haptic design, IOL thickest area and ophthalmic viscosurgical device (OVD) was studied by ejecting seven IOLs with four syringe-type injectors of different sizes, 3.0, 2.2 and 1.8 mm. In all injectors, plate hydrophilic IOLs present the lowest resistance forces; hydrated C-loop hydrophobic IOLs present higher forces and the C-loop hydrophobic IOL in dry conditions presents the highest resistance forces. All IOLs could be properly delivered with an injector size of 2.2 mm, making injector sizes of 3.0 mm outdated. The injector size of 1.8 mm damaged several IOLs. IOL material and cartridge nozzle size were the most influential parameters in IOL delivery. IOL thickest area was also relevant but in a lesser extent whereas IOL haptic design was not as relevant

Estudio experimental de una barrera acústica compuesta de cenizas volantes

Although fly ash is commonly used as an additive to cement, large amounts of this material are disposed in landfills. To mitigate, it would be interesting to develop new products in which fly ash can be easily used and required in large quantities. In this work, fly ash is added to manufacture eco-friendly materials with acceptable acoustic and non-acoustic properties and a low cost. We built a barrier composed of fly ash (60 wt.%), type II Portland cement (25 wt.%), vermiculite (14.5 wt.%) and polypropylene fibers (0.5 wt.%). The barrier complied with the mechanical requirements of European standards. The sound absorption coefficient and the airborne sound insulation were determined in a reverberation room, and the barrier was classified as A2 and B3. No leaching problems were observed.Aunque las cenizas volantes se usan comúnmente como una adición en la fabricación del cemento, grandes cantidades se siguen depositando en vertedero. Para mitigar este problema, es interesante desarrollar nuevos productos en los que las cenizas volantes se puedan usar fácilmente en grandes cantidades. En este trabajo, se emplean cenizas volantes para fabricar materiales con una alta absorción acústica, con propiedades mecánicas aceptables y un bajo coste. Se ha construido una barrera compuesta de cenizas volantes (60% en peso), cemento Portland tipo II (25% en peso), vermiculita (14.5% en peso) y fibras de polipropileno (0.5% en peso). La barrera cumplió con los requisitos mecánicos establecidos de las normas europeas. El coeficiente de absorción acústica y el aislamiento acústico en el aire se han determinado en una sala de reverberación, y la barrera se clasificó como A2 y B3. No se han observado problemas de lixiviación

Reliability of the resonance frequency analysis values in new prototype transepithelial abutments: A prospective clinical study

Resonance frequency analysis (RFA) requires abutment disconnection to monitor implant stability. To overcome this limitation, an experimental transepithelial abutment was designed to allow a SmartPeg to be screwed onto it, in order to determine the prototype abutments repeatability and reproducibility using Osstell ISQ and to assess whether implant length and diameter have an influence on the reliability of these measurements. RFA was conducted with a SmartPeg screwed directly into the implant and onto experimental abutments of different heights of 2, 3.5 and 5 mm. A total of 32 patients (116 implants) were tested. RFA measurements were taken twice for each group from mesial, distal, buccal and palatal/lingual surfaces. Mean values and SD were calculated and Intraclass Correlation Coefficients (ICC) (p < 0.05, IC 95%). The implant stability quotient (ISQ) mean values were 72.581 measured directly to implant and 72.899 (2 mm), 72.391 (3.5 mm) and 71.458 (5 mm) measured from the prototypes. ICC between measurements made directly to implant and through 2-, 3.5-and 5-mm abutments were 0.908, 0.919 and 0.939, respectively. RFA values registered through the experimental transepithelial abutments achieved a high reliability. Neither the implant length nor the diameter had any influence on the measurements’ reliability

Characterization of Auditory Disability and Its Relation to the Resilience

The objective of the work is to establish the characterization of the auditory disability and its relationship with resilience at the Technical University of Manabí. The article shows a conceptual analysis related to the inclusion and social integration of disabled students. Based on the fact that the person with disabilities grows and develops in the same way as that of people without disabilities and what usually happens is that disabled people are rejected and discriminated against based on a prefabricated and erroneous conceptualization of these people. The results associated with the application of the SV-RES test prepared by the researchers are shown (Saavedra &amp; Villalta, 2008b). Characterization of the auditory deficit is made in the students, and the limitations that derive from it are pointed out. We analyze the particularities related to communication with students who have a hearing disability and resilience in this type of student, where some personal highlights that in this sense constitute an example of resilience. Finally, the results related to the study of the relationship between students' hearing disability and the level of resilience dimensions are shown

Consumo y valor nutritivo del ensilado de "Calamagrostis antoniana" y "Avena sativa" asociada en diferentes proporciones en alpacas ("Vicugna pacos")

The experiment aimed to assess the nutritional value of the silage Calamagrostis antoniana and Avena sativa in different proportions (treatments): chemical composition in terms of dry matter (%), crude protein (%), crude fiber (%) and intake voluntary (gr.MS / day) in alpaca tuis lower in 6 treatments: T1 (100% Calamagrostis antoniana T2 (80% and 20% Calamagrostis antoniana and Avena sativa), T3 (60% Calamagrostis antoniana and 40% Avena sativa), T4 (40% and 60% Calamagrostis antoniana and Avena sativa), T5 (20% and 80% Calamagrostis antoniana and Avena sativa) and T6 (100% Avena sativa). Obtaining microsilos held in silage (4 replicates per treatment). Voluntary intake was assessed in 24 male alpacas, tuis smaller breed huacaya (4 replicates per treatment) for 21 days. The experiment was conducted in a completely randomized design. The Calamagrostis antoniana and Avena sativa silage as associated in different proportions (treatments), varies statistically (p &lt;0.05) in the content of MS (%), PT (%) and FC (%) recorded higher values silage, for T1 (55.60% MS), T6 (11.02% PT) and T1 (33.18% FC). Regarding the voluntary intake of silage and Avena sativa and Calamagrostis antoniana in alpacas, silage that had greater treatment acceptance was T4 and T5, consuming an average of voluntarily: 307.18 and 226.87 (gr. MS / day / animal), respectively.El experimento tuvo el objetivo de evaluar el valor nutritivo del ensilado de Calamagrostis antoniana y Avena sativa en diferentes proporciones (tratamientos): composición química en términos de materia seca (%), proteína cruda (%), fibra cruda (%); y consumo voluntario (gr.MS/día) en alpacas tuis menor, distribuidas en 6 tratamientos: T1 (100% Calamagrostis antoniana), T2 (80% Calamagrostis antoniana y 20% Avena sativa), T3 (60% Calamagrostis antoniana y 40% de Avena sativa), T4 (40% Calamagrostis antoniana y 60% Avena sativa), T5 (20% Calamagrostis antoniana y 80% Avena sativa) y T6 (100% Avena sativa). La obtención del ensilado se realizó en microsilos (4 repeticiones por tratamiento). El consumo voluntario se evaluó en 24 alpacas machos, tuis menor, de la raza huacaya (4 repeticiones por tratamiento), durante 21 días. El experimento fue conducido en un diseño completamente aleatorizado. El Calamagrostis antoniana y Avena sativa en forma de ensilado, asociada en sus diferentes proporciones (tratamientos), varia estadísticamente (p&lt;0.05) en cuanto  al contenido de MS(%), PT(%) y FC(%); registrándose valores mayores del ensilado, en el tratamiento T1 (55.60% MS), T6 (11.02% PT) y T1(33.18% FC). En cuanto al consumo voluntario del ensilado de Calamagrostis antoniana y Avena sativa, en las alpacas, los ensilados que tuvieron una mayor aceptación fue el tratamiento T4 y T5, llegando a consumir voluntariamente un promedio de: 307.18 y 226.87 (gr. MS/día/animal), respectivamente

Linked data technology at the service of the media

The application of technologies linked open data (LOD) is analyzed in the environment of the media through the study of datasets, specific to this area, currently present in LOD cloud diagram. Through the application of a methodology mainly descriptive the article is structured around three main sections: in the first the concept of LOD is analyzed; then the dataset study concerning the media is performed, and finally, each of these sets present in the Mannheim catalog are discussed. It is concluded highlighting the main features found and suggesting possible researches on this topic