25 research outputs found
Modelling the supernova-driven ISM in different environments
We use hydrodynamical simulations in a (256 pc)3 periodic box to model the impact of supernova (SN) explosions on the multiphase interstellar medium (ISM) for initial densities n=0.5-30cm−3 and SN rates 1-720Myr−1. We include radiative cooling, diffuse heating, and the formation of molecular gas using a chemical network. The SNe explode either at random positions, at density peaks, or both. We further present a model combining thermal energy for resolved and momentum input for unresolved SNe. Random driving at high SN rates results in hot gas (T≳106K) filling >90 per cent of the volume. This gas reaches high pressures (10450 per cent), residing in small, dense clumps. Such a model might resemble the dense ISM in high-redshift galaxies. Peak driving results in huge radiative losses, producing a filamentary ISM with virtually no hot gas, and a small molecular hydrogen mass fraction (≪1 per cent). Varying the ratio of peak to random SNe yields ISM properties in between the two extremes, with a sharp transition for equal contributions. The velocity dispersion in H i remains≲10 km s−1 in all cases. For peak driving, the velocity dispersion in Hα can be as high as 70 km s−1 due to the contribution from young, embedded SN remnant
Modelling the supernova-driven ISM in different environments
We use hydrodynamical simulations in a periodic box to
model the impact of supernova (SN) explosions on the multi-phase interstellar
medium (ISM) for initial densities cm and SN rates
Myr. We include radiative cooling, diffuse heating, and the formation of
molecular gas using a chemical network. The SNe explode either at random
positions, at density peaks, or both. We further present a model combining
thermal energy for resolved and momentum input for unresolved SNe. Random
driving at high SN rates results in hot gas ( K) filling %
of the volume. This gas reaches high pressures (
K cm) due to the combination of SN explosions in the hot, low density
medium and confinement in the periodic box. These pressures move the gas from a
two-phase equilibrium to the single-phase, cold branch of the cooling curve.
The molecular hydrogen dominates the mass (%), residing in small, dense
clumps. Such a model might resemble the dense ISM in high-redshift galaxies.
Peak driving results in huge radiative losses, producing a filamentary ISM with
virtually no hot gas, and a small molecular hydrogen mass fraction (%).
Varying the ratio of peak to random SNe yields ISM properties in between the
two extremes, with a sharp transition for equal contributions. The velocity
dispersion in HI remains km s in all cases. For peak
driving the velocity dispersion in H can be as high as km
s due to the contribution from young, embedded SN remnants.Comment: 19 pages, 12 figures, 2 tables. Accepted for publication in MNRAS.
Minor revisions to match published versio
A new mechanical stellar wind feedback model for the Rosette Nebula
The famous Rosette Nebula has an evacuated central cavity formed from the stellar winds ejected from the 2–6 Myr old codistant and comoving central star cluster NGC 2244. However, with upper age estimates of less than 110 000 yr, the central cavity is too young compared to NGC 2244 and existing models do not reproduce its properties. A new proper motion study herein using Gaia data reveals the ejection of the most massive star in the Rosette, HD 46223, from NGC 2244 occurred 1.73 (+0.34, −0.25) Myr (1σ uncertainty) in the past. Assuming this ejection was at the birth of the most massive stars in NGC 2244, including the dominant centrally positioned HD 46150, the age is set for the famous ionized region at more than 10 times that derived for the cavity. Here, we are able to reproduce the structure of the Rosette Nebula, through simulation of mechanical stellar feedback from a 40 Mₒ star in a thin sheet-like molecular cloud. We form the 135 000 Mₒ cloud from thermally unstable diffuse interstellar medium (ISM) under the influence of a realistic background magnetic field with thermal/magnetic pressure equilibrium. Properties derived from a snapshot of the simulation at 1.5 Myr, including cavity size, stellar age, magnetic field, and resulting inclination to the line of sight, match those derived from observations. An elegant explanation is thus provided for the stark contrast in age estimates based on realistic diffuse ISM properties, molecular cloud formation and stellar wind feedback
Growth Hormone Improves Growth Retardation Induced by Rapamycin without Blocking Its Antiproliferative and Antiangiogenic Effects on Rat Growth Plate
Rapamycin, an immunosuppressant agent used in renal transplantation with antitumoral properties, has been reported to impair longitudinal growth in young individuals. As growth hormone (GH) can be used to treat growth retardation in transplanted children, we aimed this study to find out the effect of GH therapy in a model of young rat with growth retardation induced by rapamycin administration. Three groups of 4-week-old rats treated with vehicle (C), daily injections of rapamycin alone (RAPA) or in combination with GH (RGH) at pharmacological doses for 1 week were compared. GH treatment caused a 20% increase in both growth velocity and body length in RGH animals when compared with RAPA group. GH treatment did not increase circulating levels of insulin-like growth factor I, a systemic mediator of GH actions. Instead, GH promoted the maturation and hypertrophy of growth plate chondrocytes, an effect likely related to AKT and ERK1/2 mediated inactivation of GSK3β, increase of glycogen deposits and stabilization of β-catenin. Interestingly, GH did not interfere with the antiproliferative and antiangiogenic activities of rapamycin in the growth plate and did not cause changes in chondrocyte autophagy markers. In summary, these findings indicate that GH administration improves longitudinal growth in rapamycin-treated rats by specifically acting on the process of growth plate chondrocyte hypertrophy but not by counteracting the effects of rapamycin on proliferation and angiogenesis
Peabody Picture Vocabulary Test-III: Normative data for Spanish-speaking pediatric population
OBJECTIVE: To generate normative data for the Peabody Picture Vocabulary Test-III (PPVT-III) in Spanish-speaking
pediatric populations.
METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador,
Honduras, Guatemala, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the PPVT-III
as part of a larger neuropsychological battery. PPVT-III scores were normed using multiple linear regressions and standard
deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in
the analyses.
RESULTS: The final multiple linear regression models showed main effects for age in all countries, such that scores increased
linearly as a function of age. In addition, age2 had a significant effect in all countries, except Guatemala and Paraguay. Models
showed that children whose parent(s) had a MLPE >12 years obtained higher scores compared to children whose parent(s)
had a MLPE ≤12 years in all countries, except for Cuba, Peru, and Puerto Rico. Sex affected scores for Chile, Ecuador,
Guatemala, Mexico, and Spain.
CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate interpretation of the PPVT-III when used in pediatric populations
4kscore test, prostate cancer prevention trial-risk calculator y european research screening prostate-risk calculator en la predicción del cáncer de próstata de alto grado; estudio preliminar
Introducción: Frente al sobrediagnóstico y al sobretratamiento en cáncer de próstata (CaP) se establecen estrategias terapéuticas como la vigilancia activa o la terapia focal, o métodos para precisar el diagnóstico del CaP de alto grado (CaP-AG), Gleason = 7, como la resonancia magnética multiparamétrica o nuevos marcadores como el 4Kscore Test (4KsT).: Es nuestro propósito testar mediante un estudio piloto la capacidad del 4KsT como identificador de CaP-AG (suma de Gleason = 7) en biopsia de próstata (Bx) y compararlo con otros modelos pronósticos multivariantes disponibles, como el Prostate Cancer Prevention Trial-Risk Calculator 2.0 (PCPTRC 2.0) y el European Research Screening Prostate Cancer-Risk Calculator 4 (ERSPC-RC 4).
Material y métodos: Cincuenta y un pacientes sometidos a BxP según práctica clínica habitual, con un mínimo de 10 cilindros. Diagnóstico de CaP-AG consensuado por 4 uropatólogos. Comparación de las predicciones ofrecidas por los diferentes modelos mediante prueba U Mann-Whitney, áreas bajo la curva ROC (AUC) (test de DeLong), funciones de densidad de probabilidad, diagramas de caja y curvas de utilidad clínica (CUC).
Resultados: Un 43% presentaron CaP y un 23,5% CaP-AG. Las medianas de probabilidad de 4KsT, PCPTRC 2.0 y ERSPC-RC 4 fueron significativamente diferentes entre los pacientes con CaP-AG y no CaP-AG (p = 0,022), siendo más diferenciadas en el caso de 4KsT (mediana en CaP-AG: 51,5% [percentil 25-75: 25-80,5%], frente a 16% [P 25-75: 8-26,5%] en no CaP-AG [p = 0,002]). Todos los modelos mostraron AUC por encima de 0,7 sin diferencias significativas entre ninguno de ellos y 4KsT (p = 0,20). Las funciones de densidad de probabilidad y diagramas de caja muestran una buena capacidad discriminativa, especialmente en los modelos de ERSPC-RC 4 y 4KsT. Las CUC muestran como un punto de corte del 9% de 4KsT identifica a todos los CaP-AG y permite un ahorro del 22% de biopsias, similar a lo que ocurre con los modelos de ERSPC-RC 4 y un punto de corte del 3%.
Conclusiones: Los modelos predictivos evaluados ofrecen una buena capacidad de discriminación del CaP-AG en Bx. 4KsT es un buen modelo clasificatorio en su conjunto, seguido de ERSPC-RC 4 y PCPTRC 2.0. Las CUC permiten sugerir puntos de corte de decisión clínica: 9% para 4KsT y 3% en ERSPC-RC 4. Este estudio preliminar debe ser interpretado con cautela por su limitado tamaño muestral.
Introduction: To prevent the overdiagnosis and overtreatment of prostate cancer (PC), therapeutic strategies have been established such as active surveillance and focal therapy, as well as methods for clarifying the diagnosis of high-grade prostate cancer (HGPC) (defined as a Gleason score =7), such as multiparametric magnetic resonance imaging and new markers such as the 4Kscore test (4. KsT).By means of a pilot study, we aim to test the ability of the 4. KsT to identify HGPC in prostate biopsies (Bx) and compare the test with other multivariate prognostic models such as the Prostate Cancer Prevention Trial Risk Calculator 2.0 (PCPTRC 2.0) and the European Research Screening Prostate Cancer Risk Calculator 4 (ERSPC-RC 4).
Material and methods: Fifty-one patients underwent a prostate Bx according to standard clinical practice, with a minimum of 10 cores. The diagnosis of HGPC was agreed upon by 4 uropathologists. We compared the predictions from the various models by using the Mann-Whitney U test, area under the ROC curve (AUC) (DeLong test), probability density function (PDF), box plots and clinical utility curves.
Results: Forty-three percent of the patients had PC, and 23.5% had HGPC. The medians of probability for the 4. KsT, PCPTRC 2.0 and ERSPC-RC 4 were significantly different between the patients with HGPC and those without HGPC (p=.022) and were more differentiated in the case of 4. KsT (51.5% for HGPC 25-75 percentile: 25-80.5%] vs. 16% P 25-75: 8-26.5%] for non-HGPC; p = 002). All models presented AUCs above 0.7, with no significant differences between any of them and 4. KsT (p=.20). The PDF and box plots showed good discriminative ability, especially in the ERSPC-RC 4 and 4. KsT models. The utility curves showed how a cutoff of 9% for 4. KsT identified all cases of HGPC and provided a 22% savings in biopsies, which is similar to what occurs with the ERSPC-RC 4 models and a cutoff of 3%.
Conclusions: The assessed predictive models offer good discriminative ability for HGPCs in Bx. The 4. KsT is a good classification model as a whole, followed by ERSPC-RC 4 and PCPTRC 2.0. The clinical utility curves help suggest cutoff points for clinical decisions: 9% for 4. KsT and 3% for ERSPC-RC 4. This preliminary study should be interpreted with caution due to its limited sample size
Whole-genome genotyping of grape using a panel of microsatellite
The use of microsatellite markers in large-scale genetic studies is limited by its low throughput and high cost and labor requirements. Here, we provide a panel of 45 multiplex PCRs for fast and cost-efficient genome-wide fluorescence-based microsatellite analysis in grapevine. The developed multiplex PCRs panel (with up to 15-plex) enables the scoring of 270 loci covering all the grapevine genome (9 to 20 loci/chromosome) using only 45 PCRs and sequencer runs. The 45 multiplex PCRs were validated using a diverse grapevine collection of 207 accessions, selected to represent most of the cultivated Vitis vinifera genetic diversity. Particular attention was paid to quality control throughout the whole process (assay replication, null allele detection, ease of scoring). Genetic diversity summary statistics and features of electrophoretic profiles for each studied marker are provided, as are the genotypes of 25 common cultivars that could be used as references in other studies
Evaluación de la toxicidad subcrónica del extracto acuoso de las hojas de yacón (Smallanthus sonchifolius) administrado por vía oral en ratas.
Evaluación de la toxicidad subcrónica del extracto acuoso de las hojas de yacón (Smallanthus sonchifolius) administrado por vía oral en ratas