Tratamiento de lesiones de caries microcavitadas mediante sellantes de resina y vidrio ionómero en dientes permanentes de niños de 6 a 11 años, seguimiento a 6 meses, 2015.

82 p.Se llevó a cabo un estudio Clínico Controlado Aleatorizado (RCT) donde dos tipos de sellantes fueron aplicados sobre primeros molares permanentes en lesiones ICDAS II código 3. El RCT se llevó a cabo en niños de entre 6 y 11 años que se atienden en las Clínicas Odontológicas de la Universidad de Talca, en Talca. Se trataron 151 lesiones de caries con dos tipos de materiales en base a resinas o vidrio ionómero (VI), las que fueron divididas de forma aleatoria. Los sujetos tuvieron una evaluación tanto clínica como radiográfica, en tiempo “0” (baseline) y un seguimiento a los 6 meses. Se evaluó la progresión de caries y retención del material utilizado, y a su vez se asociaron con respecto a diferentes variables sociodemográficas. Al seguimiento de los 6 meses, los resultados indicaron que no existe progresión de caries tanto clínica como radiográfica al comparar ambos materiales. No hubo asociación entre progresión de caries, el éxito clínico y las diferentes variables sociodemográficas. Además en este estudio, al comparar el sellante de resina y de VI, se demostró que ambos materiales son igualmente efectivos en la detención de caries. En cuanto a la retención, no hubo diferencias entre los dos tipos de sellantes. Dado que el estudio se realizó en un tiempo limitado, se hace necesario continuar con el seguimiento y controles posteriores para obtener conclusiones más definitivas. Palabras claves:Sellante de resina, sellante de vidrio ionómero, lesión de caries, primer molar permanente, ensayo clínico y odontología mínimamente invasiva./ABSTRACT: It was carried out a Randomized Clinical Trial (RCT), where two types of sealant were applied on the first permanent molars in International Caries Detection and Assessment System II (ICDAS) code 3 lesions. The RCT was conducted on children between 6 and 11 years old that are treated on the Dental Clinic of Universidad de Talca, in Talca. To treat the 151 caries lesions it was used two types of materials based on resin or Glass Ionomer Cements (GIC). Those materials were divided randomly. The participants were first evaluated both clinical and radiographic in a baseline, and then, after six months, they were monitored. The progression of caries and the material retention were evaluated and then associated with different sociodermographic variables. The result of the six-month-monitoring showed that there is no caries progression in both clinical and radiographic, when both materials are compared. Moreover, there was no association between the caries progression, the clinic success, and the different sociodemographic variables. Besides, this study demonstrated that when sealant of resin and GIC are compared they are equally effective when detecting caries. Finally, regarding to the material retention, there were no differences between both types of sealant. Since the study was carried out in a limited time, it is necessary to continue with the monitoring and subsequent medical examinations to obtain more definitive conclusions. Key Words: Resin sealant, glass ionomer sealant, caries lesion, first permanent molars, clinical trial and minimally invasive dentistry

Análisis de la fertilidad potencial del canino (Canis Lupus Familiaris) posterior a la inyección intratesticular de Cloruro de Calcio al 20%

Una de las principales técnicas utilizadas para el control de la población canina es la castración. La técnica quirúrgica sin lugar a dudas es la más utilizada y conocida, sin embargo la opción de la castración química ha ido tomando fuerza como una alternativa a la castración quirúrgica, debido a que se considera un proceso no invasivo, económico y de fácil realización, sobre todo en casos de castración masiva de animales como control de la población callejera. En este estudio se utilizó un total de 20 caninos, los cuales se dividieron en: grupos experimentales (1, 2, 3) y grupo control. A los tres grupos experimentales se les aplicó una inyección por vía intratesticular de cloruro de calcio al 20% en ambos testículos, mientras que, al grupo control se le inyectó por la misma vía, solución fisiológica al 0,9%. Previo a esta inoculación todos los pacientes fueron sometidos a un examen físico general, examen andrológico, análisis de fertilidad mediante espermiograma y análisis plasmático de testosterona mediante radio inmuno ensayo (RIA). Al grupo experimental 1 y al grupo control, luego de 7 días post inoculación, se les realizó un nuevo análisis de fertilidad mediante espermiograma y análisis plasmático de testosterona. En el caso del grupo experimental 2 el procedimiento anterior se realizó después de 14 días de la inoculación y el grupo experimental 3, después de 21 días. En relación con el análisis espermático, el grupo experimental 1 no presentó diferencias significativas en ningún parámetro analizado. El grupo experimental 2 presentó diferencias estadísticamente significativas en volumen, concentración espermática y motilidad progresiva. El grupo experimental 3 presentó diferencias estadísticamente significativas en el volumen entre el tiempo inicial y a los 21 días posterior a la inoculación, los parámetros restantes del espermiograma no fueron analizados puesto que no se obtuvo líquido seminal en los pacientes de este grupo, indicando que a los 21 días existiría daño en el tejido testicular evidenciado por la ausencia de espermatogénesis. Los resultados del análisis plasmático de testosterona indicaron que solo en el grupo experimental 3 la concentración de ésta hormona presentó una disminución estadísticamente significativa, por lo cual a partir de los 21 días post-inoculación la concentración de esta hormona comenzaría a descender. Debido a los resultados obtenidos podemos concluir que la utilización de cloruro de calcio al 20% vía intratesticular es una técnica eficaz en lograr la castración, lo que se manifiesta con mayor seguridad a partir de los 21 días post inyección, fácil de realizar y sin efectos adversos, lo que la hace una opción válida, sobre todo en planes de esterilización masiva.  

On Variations in the Peak Luminosity of Type Ia Supernovae

We explore the idea that the observed variations in the peak luminosities of Type Ia supernovae originate in part from a scatter in metallicity of the main-sequence stars that become white dwarfs. Previous, numerical, studies have not self-consistently explored metallicities greater than solar. One-dimensional Chandrasekhar mass models of SNe Ia produce most of their 56Ni in a burn to nuclear statistical equilibrium between the mass shells 0.2 and 0.8 solar masses, for which the electron to nucleon ratio is constant during the burn. We show analytically that, under these conditions, charge and mass conservation constrain the mass of 56Ni produced to depend linearly on the original metallicity of the white dwarf progenitor. Detailed post-processing of W7-like models confirms this linear dependence. The effect that we identify is most evident at metallicities larger than solar, and is in agreement with previous self-consistent calculations over the metallicity range common to both calculations. The observed scatter in the metallicity (1/3--3 times solar) of the solar neighborhood is enough to induce a 25% variation in the mass of 56Ni ejected by Type Ia supernovae. This is sufficient to vary the peak V-band brightness by approximately 0.2. This scatter in metallicity is present out to the limiting redshifts of current observations (z < 1). Sedimentation of 22Ne can possibly amplify the variation in 56Ni mass up to 50%. Further numerical studies can determine if other metallicity-induced effects, such as a change in the mass of the 56Ni-producing region, offset or enhance this variation.Comment: 4 pages, 1 figure, to appear in ApJL. Uses emulateapj.cls (included

Optical and Infrared Photometry of the Unusual Type Ia Supernova 2000cx

We present optical and infrared photometry of the unusual Type Ia supernova 2000cx. With the data of Li et al. (2001) and Jha (2002), this comprises the largest dataset ever assembled for a Type Ia SN, more than 600 points in UBVRIJHK. We confirm the finding of Li et al. regarding the unusually blue B-V colors as SN 2000cx entered the nebular phase. Its I-band secondary hump was extremely weak given its B-band decline rate. The V minus near infrared colors likewise do not match loci based on other slowly declining Type Ia SNe, though V-K is the least ``abnormal''. In several ways SN 2000cx resembles other slow decliners, given its B-band decline rate (Delta m_15(B) = 0.93), the appearance of Fe III lines and weakness of Si II in its pre-maximum spectrum, the V-K colors and post-maximum V-H colors. If the distance modulus derived from Surface Brightness Fluctuations of the host galaxy is correct, we find that the rate of light increase prior to maximum, the characteristics of the bolometric light curve, and the implied absolute magnitude at maximum are all consistent with a sub-luminous object with Delta m_15(B) ~ 1.6-1.7 having a higher than normal kinetic energy.Comment: 46 pages, 17 figures, to be published in Publications of the Astronomical Society of the Pacifi

On the fraction of intermediate-mass close binaries that explode as type-Ia supernovae

Type-Ia supernovae (SNe-Ia) are thought to result from a thermonuclear runaway in white dwarfs (WDs) that approach the Chandrasekhar limit, either through accretion from a companion or a merger with another WD. I compile observational estimates of the fraction eta of intermediate-mass stars that eventually explode as SNe-Ia, supplement them with several new estimates, and compare them self-consistently. The estimates are based on five different methods, each utilising some observable related to the SN-Ia rate, combined with assumptions regarding the IMF: the ratio of SN-Ia to core-collapse rates in star-forming galaxies; the SN-Ia rate per unit star-formation rate; the SN-Ia rate per unit stellar mass; the iron to stellar mass ratio in galaxy clusters; and the abundance ratios in galaxy clusters. The five methods indicate that a fraction in the range eta~2-40% of all stars with initial masses of 3-8 M_sun (the generally assumed SN-Ia progenitors) explode as SNe-Ia. A fraction of eta~15% is consistent with all five methods for a range of plausible IMFs. Considering also the binarity fraction among such stars, the mass ratio distribution, the separation distribution, and duplicity (every binary can produce only one SN-Ia explosion), this implies that nearly every intermediate mass close binary ends up as a SN-Ia, or possibly more SNe-Ia than progenitor systems. Theoretically expected fractions are generally one to two orders of magnitude lower. The problem could be solved: if all the observational estimates are in error; or with a ``middle-heavy'' IMF; or by some mechanism that strongly enhances the efficiency of binary evolution toward SN-Ia explosion; or by a non-binary origin for SNe-Ia.Comment: MNRAS, accepted versio

The Rise Time of Type Ia Supernovae from the Supernova Legacy Survey

We compare the rise times of nearby and distant Type Ia supernovae (SNe Ia) as a test for evolution using 73 high-redshift spectroscopically-confirmed SNe Ia from the first two years of the five year Supernova Legacy Survey (SNLS) and published observations of nearby SN. Because of the ``rolling'' search nature of the SNLS, our measurement is approximately 6 times more precise than previous studies, allowing for a more sensitive test of evolution between nearby and distant supernovae. Adopting a simple $t^2$ early-time model (as in previous studies), we find that the rest-frame $B$ rise times for a fiducial SN Ia at high and low redshift are consistent, with values $19.10^{+0.18}_{-0.17}({stat}) \pm 0.2 ({syst})$ and $19.58^{+0.22}_{-0.19}$ days, respectively; the statistical significance of this difference is only 1.4 \sg . The errors represent the uncertainty in the mean rather than any variation between individual SN. We also compare subsets of our high-redshift data set based on decline rate, host galaxy star formation rate, and redshift, finding no substantive evidence for any subsample dependence.Comment: Accepted for publication in AJ; minor changes (spelling and grammatical) to conform with published versio

Medium Modification of The Pion-Pion Interaction at Finite Density

We discuss medium modifications of the unitarized pion-pion interaction in the nuclear medium. We incorporate both the effects of chiral symmetry restoration and the influence of collective nuclear pionic modes originating from the p-wave coupling of the pion to delta-hole configurations. We show in particular that the dropping of the sigma meson mass significantly enhances the low energy structure created by the in-medium collective pionic modes.Comment: 26 pages, 7 figures included, Latex fil

Optical and Near-Infrared Observations of the Highly Reddened, Rapidly Expanding Type Ia Supernova 2006X in M100

We present extensive optical (UBVRI), near-infrared (JK) light curves and optical spectroscopy of the Type Ia supernova (SN) 2006X in the nearby galaxy NGC 4321 (M100). Our observations suggest that either SN 2006X has an intrinsically peculiar color evolution, or it is highly reddened [E(B - V)_{host} = 1.42+/-0.04 mag] with R_V = 1.48+/-0.06, much lower than the canonical value of 3.1 for the average Galactic dust. SN 2006X also has one of the highest expansion velocities ever published for a SN Ia. Compared with the other SNe Ia we analyzed, SN 2006X has a broader light curve in the U band, a more prominent bump/shoulder feature in the V and R bands, a more pronounced secondary maximum in the I and near-infrared bands, and a remarkably smaller late-time decline rate in the B band. The B - V color evolution shows an obvious deviation from the Lira-Phillips relation at 1 to 3 months after maximum brightness. At early times, optical spectra of SN 2006X displayed strong, high-velocity features of both intermediate-mass elements (Si, Ca, and S) and iron-peak elements, while at late times they showed a relatively blue continuum, consistent with the blue U-B and B-V colors at similar epochs. A light echo and/or the interaction of the SN ejecta and its circumstellar material may provide a plausible explanation for its late-time photometric and spectroscopic behavior. Using the Cepheid distance of M100, we derive a Hubble constant of 72.7+/-8.2 km s^{-1} Mpc^{-1}(statistical) from the normalized dereddened luminosity of SN 2006X. We briefly discuss whether abnormal dust is a universal signature for all SNe Ia, and whether the most rapidly expanding objects form a subclass with distinct photometric and spectroscopic properties.Comment: 48 pages, 20 figures and 11 tables. Accepted Version (ApJ, 2008, March issue

Type Ia Supernovae as Sites of p-process: Two-Dimensional Models Coupled to Nucleosynthesis

We explore SNe Ia as p-process sites in the framework of two-dimensional SN Ia delayed detonation and pure deflagration models. The WD precursor is assumed to have reached the Chandrasekhar mass in a binary system by mass accretion from a giant/main sequence companion. We use enhanced s-seed distributions, obtained from a sequence of thermal pulse instabilities both in the AGB phase and in the accreted material. We apply the tracer-particle method to reconstruct the nucleosynthesis by the thermal histories of Lagrangian particles, passively advected in the hydrodynamic calculations. For each particle we follow the explosive nucleosynthesis with a detailed network for all isotopes up to 209Bi. We find that SNe Ia can produce a large amount of p-nuclei, both the light p-nuclei below A=120 and the heavy-p nuclei, at quite flat average production factors, tightly related to the s-process seed distribution. For the first time, we find a stellar source able to produce both, light and heavy p-nuclei almost at the same level as 56Fe, including the very debated neutron magic 92,94Mo and 96,98Ru. We also find that there is an important contribution from p-process nucleosynthesis to the s-only nuclei 80Kr, 86Sr, to the neutron magic 90Zr, and to the neutron-rich 96Zr. Finally, we investigate the metallicity effect on p-process. Starting with different s-process seed distributions, for two metallicities Z = 0.02 and Z = 0.001, running SNe Ia models with different initial composition, we estimate that SNe Ia can contribute to, at least, 50% of the solar p-process composition.Comment: 62 pages, 14 figures, 5 tables, ApJ in pres

The ESSENCE Supernova Survey: Survey Optimization, Observations, and Supernova Photometry

We describe the implementation and optimization of the ESSENCE supernova survey, which we have undertaken to measure the equation of state parameter of the dark energy. We present a method for optimizing the survey exposure times and cadence to maximize our sensitivity to the dark energy equation of state parameter w=P/rho c^2 for a given fixed amount of telescope time. For our survey on the CTIO 4m telescope, measuring the luminosity distances and redshifts for supernovae at modest redshifts (z~0.5 +- 0.2) is optimal for determining w. We describe the data analysis pipeline based on using reliable and robust image subtraction to find supernovae automatically and in near real-time. Since making cosmological inferences with supernovae relies crucially on accurate measurement of their brightnesses, we describe our efforts to establish a thorough calibration of the CTIO 4m natural photometric system. In its first four years, ESSENCE has discovered and spectroscopically confirmed 102 type Ia SNe, at redshifts from 0.10 to 0.78, identified through an impartial, effective methodology for spectroscopic classification and redshift determination. We present the resulting light curves for the all type Ia supernovae found by ESSENCE and used in our measurement of w, presented in Wood-Vasey et al, 2007.Comment: Submitted to ApJ. Companion paper to Wood-Vasey et al (2007). Electronic tables available at http://www.ctio.noao.edu/essence/wresult