20 research outputs found
Análisis semicuantitativo del calcio y fósforo en los tejidos calcificados de la mandíbula
El objetivo de nuestra investigación es realizar un estudio microanalítico semicuantitativo del
calcio y el fósforo en los tejidos calcificados de la mandíbula. Dentro de este estudio se pretende
calcular el valor de la ratio Ca/P por métodos semicuantitativos y compararlo con los valores
estequiométricos de la ratio Ca/P de la hidroxiapatita referidos en la literatura; conocer los valores
de la ratio Ca/P obtenidos para el tejido condroide, el hueso lamelar, el hueso fibrorreticular y el
cartílago calcificado en las muestras fetales, por una parte, y adultas, por otra; y si existen o no
diferencias significativas en la proporción Ca/P obtenidos para feto y adulto. El análisis morfológico
de los tejidos calcificados fue realizado por medio de Microrradiografía Electrónica de Barrido
(MEB) por electrones retrodispersados (Backscattering), y los resultados permiten afirmar que la
ratio obtenida por análisis semicuantitativo mediante dispersión de rayos X de los tejidos calcificados
(condroide, hueso lamelar y fibrorreticular) se encuentra más próxima a 1, y que no existen diferencias
significativas entre las muestras fetales y de adulto en los tejidos analizados
Dust environment and dynamical history of a sample of short-period comets: II. 81P/Wild 2 and 103P/Hartley 2
Aims. This paper is a continuation of the first paper in this series, where we presented an extended study of the dust environment of a sample of short-period comets and their dynamical history. On this occasion, we focus on comets 81P/Wild 2 and 103P/Hartley 2, which are of special interest as targets of the spacecraft missions Stardust and EPOXI. Methods. As in the previous study, we used two sets of observational data: a set of images, acquired at Sierra Nevada and Lulin observatories, and the Afρ data as a function of the heliocentric distance provided by the amateur astronomical association Cometas-Obs. The dust environment of comets (dust loss rate, ejection velocities, and size distribution of the particles) was derived from our Monte Carlo dust tail code. To determine their dynamical history we used the numerical integrator Mercury 6.2 to ascertain the time spent by these objects in the Jupiter family Comet region. Results. From the dust analysis, we conclude that both 81P/Wild 2 and 103P/Hartley 2 are dusty comets, with an annual dust production rate of 2.8 × 109 kg yr-1 and (0.4-1.5) × 109 kg yr-1, respectively. From the dynamical analysis, we determined their time spent in the Jupiter family Comet region as ~40 yr in the case of 81P/Wild 2 and ~1000 yr for comet 103P/Hartley 2. These results imply that 81P/Wild 2 is the youngest and the most active comet of the eleven short-period comets studied so far, which tends to favor the correlation between the time spent in JFCs region and the comet activity previously discussed
A Delphi-method-based consensus guideline for definition of treatment-resistant depression for clinical trials
Criteria for treatment-resistant depression (TRD) and partially responsive depression (PRD) as subtypes of major depressive disorder (MDD) are not unequivocally defined. In the present document we used a Delphi-method-based consensus approach to define TRD and PRD and to serve as operational criteria for future clinical studies, especially if conducted for regulatory purposes. We reviewed the literature and brought together a group of international experts (including clinicians, academics, researchers, employees of pharmaceutical companies, regulatory bodies representatives, and one person with lived experience) to evaluate the state-of-the-art and main controversies regarding the current classification. We then provided recommendations on how to design clinical trials, and on how to guide research in unmet needs and knowledge gaps. This report will feed into one of the main objectives of the EUropean Patient-cEntric clinicAl tRial pLatforms, Innovative Medicines Initiative (EU-PEARL, IMI) MDD project, to design a protocol for platform trials of new medications for TRD/PRD. © 2021, The Author(s).EU/EFPIA/Innovative Medicines Initiative 2 Joint Undertaking
Estudio histoquimico de la fisis tibial de ratas diabeticas jovenes
Se realiza un estudio histoquímico, con la técnica del azul alcián, en la fisis tibial de ratas machos de un mes diabetizadas mediante inyección de streptozotocin. Se comparan los resultados con un grupo control comprobándose que tras la primera semana, aunque las fisis diabéticas son más estrechas, no existen diferencias en la captación del colorante; a partir de la segunda semana éstas muestran progresivamente menor avidez por el azul alcián que los controles, indicando una menor producción de proteoglicanos, especialmente a nivel germinal y proliferativo. La precocidad en la aparición de alteraciones sugiere el observar más concienzudamente la posibilidad de problemas ortopédicos en el crecimiento de niños diabéticos, especialmente aquellos diagnosticados con retraso
Distinctive archaeal composition of an artisanal crystallizer pond and functional insights into salt-saturated hypersaline environment adaptation
Hypersaline environments represent some of the most challenging settings for life on Earth. Extremely halophilic microorganisms have been selected to colonize and thrive in these extreme environments by virtue of a broad spectrum of adaptations to counter high salinity and osmotic stress. Although there is substantial data on microbial taxonomic diversity in these challenging ecosystems and their primary osmoadaptation mechanisms, less is known about how hypersaline environments shape the genomes of microbial inhabitants at the functional level. In this study, we analyzed the microbial communities in five ponds along the discontinuous salinity gradient from brackish to salt-saturated environments and sequenced the metagenome of the salt (halite) precipitation pond in the artisanal Cáhuil Solar Saltern system. We combined field measurements with spectrophotometric pigment analysis and flow cytometry to characterize the microbial ecology of the pond ecosystems, including primary producers and applied metagenomic sequencing for analysis of archaeal and bacterial taxonomic diversity of the salt crystallizer harvest pond. Comparative metagenomic analysis of the Cáhuil salt crystallizer pond against microbial communities from other salt-saturated aquatic environments revealed a dominance of the archaeal genus Halorubrum and showed an unexpectedly low abundance of Haloquadratum in the Cáhuil system. Functional comparison of 26 hypersaline microbial metagenomes revealed a high proportion of sequences associated with nucleotide excision repair, helicases, replication and restriction-methylation systems in all of them. Moreover, we found distinctive functional signatures between the microbial communities from salt-saturated (>30% [w/v] total salinity) compared to sub-saturated hypersaline environments mainly due to a higher representation of sequences related to replication, recombination and DNA repair in the former. The current study expands our understanding of the diversity and distribution of halophilic microbial populations inhabiting salt-saturated habitats and the functional attributes that sustain them.ISSN:1664-302
Faster implementation of scalar multiplication on Koblitz curves
We design a state-of-the-art software implementation of field and elliptic curve arithmetic in standard Koblitz curves at the 128-bit security level. Field arithmetic is carefully crafted by using the best formulae and implementation strategies available, and the increasingly common native support to binary field arithmetic in modern desktop computing platforms. The i-th power of the Frobenius automorphism on Koblitz curves is exploited to obtain new and faster interleaved versions of the well-known τNAF scalar multiplication algorithm. The usage of the τ ⌊m/3 ⌋ and τ ⌊m/4 ⌋ maps are employed to create analogues of the 3-and 4-dimensional GLV decompositions and in general, the ⌊m/s⌋-th power of the Frobenius automorphism is applied as an analogue of an s-dimensional GLV decomposition. The effectiveness of these techniques is illustrated by timing the scalar multiplication operation for fixed, random and multiple points. To our knowledge, our library was the first to compute a random point scalar multiplication in less than 10 5 clock cycles among all curves with or without endomorphisms defined over binary or prime fields. The results of our optimized implementation suggest a trade-off between speed, compliance with the published standards and side-channel protection. Finally, we estimate the performance of curvebased cryptographic protocols instantiated using the proposed techniques and compare our results to related work. Key words: Efficient software implementation, Koblitz elliptic curves, scalar multiplication.