2,528 research outputs found

    Driving-induced crossover: from classical criticality to self-organized criticality

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    We propose a spin model with quenched disorder which exhibits in slow driving two drastically different types of critical nonequilibrium steady states. One of them corresponds to classical criticality requiring fine-tuning of the disorder. The other is a self-organized criticality which is insensitive to disorder. The crossover between the two types of criticality is determined by the mode of driving. As one moves from "soft" to "hard" driving the universality class of the critical point changes from a classical order-disorder to a quenched Edwards-Wilkinson universality class. The model is viewed as prototypical for a broad class of physical phenomena ranging from magnetism to earthquakes.Comment: 4 pages, 4 figure

    A Population of Dust-rich Quasars at z ~ 1.5

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    We report Herschel SPIRE (250, 350, and 500 μm) detections of 32 quasars with redshifts 0.5 ≤z < 3.6 from the Herschel Multi-tiered Extragalactic Survey (HerMES). These sources are from a MIPS 24 μm flux-limited sample of 326 quasars in the Lockman Hole Field. The extensive multi-wavelength data available in the field permit construction of the rest-frame spectral energy distributions (SEDs) from ultraviolet to the mid-infrared for all sources, and to the far-infrared (FIR) for the 32 objects. Most quasars with Herschel FIR detections show dust temperatures in the range of 25-60 K, with a mean of 34 K. The FIR luminosities range from 10^(11.3) to 10^(13.5) L_☉, qualifying most of their hosts as ultra- or hyper-luminous infrared galaxies. These FIR-detected quasars may represent a dust-rich population, but with lower redshifts and fainter luminosities than quasars observed at ~1 mm. However, their FIR properties cannot be predicted from shorter wavelengths (0.3-20 μm, rest frame), and the bolometric luminosities derived using the 5100 Å index may be underestimated for these FIR-detected quasars. Regardless of redshift, we observed a decline in the relative strength of FIR luminosities for quasars with higher near-infrared luminosities

    Interleukin 10 (IL-10) and transforming growth factor beta (TGF- ß) expression in intestinal mucosa of alpaca crias (Vicugna pacos)

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    El objetivo del trabajo fue evaluar los niveles de expresión relativa de los genes de las citoquinas IL-10 y TGF-β en la mucosa intestinal de alpacas de 2 a 47 días de edad, clínicamente sanas. Se formaron tres grupos etarios (seis crías por grupo) conformados por alpacas de 2 a 8 días (grupo 1), 10 a 21 días (grupo 2) y 26 a 47 días (grupo 3), sin distinción de sexo o raza. Se tomó la porción media del yeyuno de cada animal, se extrajo el ARN total y se empleó la técnica RT-PCR en tiempo-real con cebadores específicos para las citoquinas en estudio. La expresión relativa de ARNm de IL10 y TGF-β fue determinada por el método comparativo 2-ΔΔCt usando como calibrador el yeyuno de tres fetos de 11 meses de gestación y como gen endógeno el gliceraldehído-3-fosfato deshidrogenasa (GAPDH). La expresión promedio de ARNm de IL-10 fue de 7.21±1.02 (grupo 1), 13.53±1.26 (grupo 2) y 18.77±1.48 (grupo 3) veces lo expresado por el grupo calibrador, mostrando diferencia significativa (p&lt;0.05) entre grupos etarios. La expresión promedio de ARNm de TGF-β fue de 2.18±0.23 (grupo 1), 3.03±0.18 (grupo 2) y 4.06±0.15 (grupo 3) veces lo expresado por el grupo calibrador, mostrando diferencia significativa (p&lt;0.05) entre grupos etarios. La expresión de ARNm de IL-10 y TGF-β fue dependiente de la edad, incrementándose significativamente con la mayor edad de las crías.The aim of the present study was to evaluate the relative expression levels of cytokines IL-10 and TGF-β in the intestinal mucosa of clinically healthy alpacas from 2 to 47 days old. The animals were classified in three age groups (six animals per group): 2-8 days old (group 1), 10-21days old (group 2) and 26-47-days old (group 3), regardless sex or breed. The midportion of jejunum of each animal was collected; total RNA was extracted and then analyzed by real-time RT-PCR technique using IL-10 and TGF-β specific primers. The relative mRNA expression analysis was done using the comparative 2-ΔΔCt method. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as housekeeping gene and jejunum of three 11-month-old fetuses were used as calibrators. The results showed that IL-10 mRNA expression levels were 7.21±1.02 (group 1), 13.53±1.26 (group 2), and 18.77±1.48 (group 3) times as expressed by the calibrate group with significant difference between age groups (p&lt;0.05). Also, TGF-β mRNA expression levels were 2.18±0.23 (group 1), 3.03±0.18 (group 2), and 4.06±0.15 (group 3) times as expressed by the calibrate group with significant difference between age groups (p&lt;0.05). The expression of IL-10 and TGF-β mRNA was age dependent, increasing significantly in older animals

    Multidrug resistant pulmonary tuberculosis treatment regimens and patient outcomes: an individual patient data meta-analysis of 9,153 patients.

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    Treatment of multidrug resistant tuberculosis (MDR-TB) is lengthy, toxic, expensive, and has generally poor outcomes. We undertook an individual patient data meta-analysis to assess the impact on outcomes of the type, number, and duration of drugs used to treat MDR-TB

    Concentración de pH en hojas de cultivares clónales de jocote (Spondias purpurea L.) en el Arboretum Alain Meyrat de la Universidad Nacional Agraria, Managua, Nicaragua

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    This research aims to determine the concentration of pH in the leaflets of 17 clonal cultivars Spondias purpurea L., located in the Arboretum Alain Meyrat of the National Agrarian University. The methodology used was developed at various times, such as the collection of plant material, selection of 20 sheets of each clonal cultivar in good condition (healthy, green and full), weighing using a balance of the green mass of leaflets separating them rachis which were labeled with the name of each clonal cultivar. Regarding the determination of the concentration of H + ions (pH) proceeded to cut the leaflets and the rachis, standard fashion using 3g of each sample were macerated with same as a porcelain mortar until ground matter. Then determined qualitatively solubility of the leaflets, using solvents such as water (H₂0), benzene (C₆H₆), ethanol (CH₃-CH₂- 0H) and carbon tetrachloride (CCl₄), using 3ml of each solvent. A pH meter was used to determine the concentration of H + ions (pH) of the samples before and after the use of solvents. It was observed that the growing San Franciscano has a higher concentration of H + ions, thus increasing acidity, maintaining this behavior in all solvents used, like dry rachis; This result led to the conclusion that the presence of organic acids is high and therefore the species is phytochemically recommended for the preparation of infusions. Regarding dry leaflets, Cook cultivar had the highest acidity.La presente investigación tiene como objetivo determinar la concentración de pH en los foliolos de 17 cultivares clónales de Spondias purpurea L., ubicados en el Arboretum Alain Meyrat de la Universidad Nacional Agraria. La metodología utilizada se desarrolló en diversos momentos: recolección del material vegetativo, selección de 20 hojas de cada cultivar clonal en buen estado (sanas, verdes y completas), pesaje de la masa verde de los foliolos separándolos del raquis rotulados con según cultivar clonal. Para la determinación de la concentración de iones H+ (pH) se procedió a recortar los foliolos y el raquis, utilizando estandarizadamente 3g de cada muestra, mismas que se maceraron con un mortero de porcelana hasta obtener materia molida. Seguidamente se determinó en forma cualitativa la solubilidad de los foliolos, haciendo uso de solventes como el agua (H₂0), benceno (C₆H₆), etanol (CH₃-CH₂-0H), y tetracloruro de carbono (CCl₄), utilizando 3ml de cada solvente. Se empleó un pHmetro para determinar la concentración de iones H+ de las muestras antes y después del uso de solventes. Se observó que el cultivar San Franciscano posee mayor concentración de iones H+, por tanto mayor acidez, manteniendo ese comportamiento en todos los solventes empleados, al igual que el raquis seco. Este resultado permitió concluir que la presencia de ácidos orgánicos es alta y, por tanto, la especie es fitoquímicamente recomendable para la elaboración de infusiones. Lo que respecta a los foliolos secos, el cultivar Cocer obtuvo la mayor acidez. Palabras clave: arboretum, cultivar, filiolos, infusiones, acidez

    The physical scale of the far-infrared emission in the most luminous submillimetre galaxies II: evidence for merger-driven star formation

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    We present high-resolution 345 GHz interferometric observations of two extreme luminous (L_{IR}>10^{13} L_sun), submillimetre-selected galaxies (SMGs) in the COSMOS field with the Submillimeter Array (SMA). Both targets were previously detected as unresolved point-sources by the SMA in its compact configuration, also at 345 GHz. These new data, which provide a factor of ~3 improvement in resolution, allow us to measure the physical scale of the far-infrared in the submillimetre directly. The visibility functions of both targets show significant evidence for structure on 0.5-1 arcsec scales, which at z=1.5 translates into a physical scale of 5-8 kpc. Our results are consistent with the angular and physical scales of two comparably luminous objects with high-resolution SMA followup, as well as radio continuum and CO sizes. These relatively compact sizes (<5-10 kpc) argue strongly for merger-driven starbursts, rather than extended gas-rich disks, as the preferred channel for forming SMGs. For the most luminous objects, the derived sizes may also have important physical consequences; under a series of simplifying assumptions, we find that these two objects in particular are forming stars close to or at the Eddington limit for a starburst.Comment: 9 pages, 3 Figures, submitted to MNRA

    A massive black hole in a low-metallicity AGN at z5.55z\sim5.55 revealed by JWST/NIRSpec IFS

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    We present JWST/NIRSpec Integral Field Spectrograph rest-frame optical data of the compact z=5.55z=5.55 galaxy GS_3073. Its prominent broad components in several hydrogen and helium lines (while absent in the forbidden lines), and the detection of a large equivalent width of He II λ4686\lambda4686, EW(He II) 20\sim20 Angstrom, unambiguously identify it as an active galactic nucleus (AGN). We measure a gas-phase metallicity of Zgas/Z0.210.04+0.08Z_{\rm gas}/Z_\odot\sim0.21^{+0.08}_{-0.04}, lower than what has been inferred for both more luminous AGN at similar redshift and lower redshift AGN. We empirically show that classical emission line ratio diagnostic diagrams cannot be used to distinguish between the primary ionisation source (AGN or star formation) for such low-metallicity systems, whereas different diagnostic diagrams involving He IIλ4686\lambda4686 prove very useful, independent of metallicity. We measure the central black hole mass to be log(MBH/M)8.200.16+0.11\log(M_{\rm BH}/M_\odot)\sim8.20^{+0.11}_{-0.16}. While this places GS_3073 at the lower end of known high-redshift black hole masses, it still appears to be over-massive compared to its host galaxy properties. We detect an outflow with projected velocity 700\gtrsim700~km/s and an ionised gas mass outflow rate of about 100 M/100\ M_\odot/yr, suggesting that GS_3073 is able to enrich the intergalactic medium with metals one billion years after the Big Bang.Comment: 15 pages, 10 figures; comments are welcome. Submitted to A&

    GA-NIFS: Black hole and host galaxy properties of two z\simeq6.8 quasars from the NIRSpec IFU

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    Integral Field Spectroscopy (IFS) with JWST NIRSpec will significantly improve our understanding of the first quasars, by providing spatially resolved, infrared spectroscopic capabilities which cover key rest-frame optical emission lines that have been previously unobservable. Here we present our results from the first two z>6 quasars observed as a part of the Galaxy Assembly with NIRSpec IFS (GA-NIFS) GTO program, DELS J0411-0907 at z=6.82 and VDES J0020-3653 at z=6.86. By observing the Hβ\beta, [OIII], and Hα\alpha emission lines in these high-z quasars for the first time, we measure accurate black hole masses, MBH=1.85e9M_{\rm{BH}}=1.85e9 and 2.9e92.9e9M_\odot, corresponding to Eddington ratios of λEdd=0.8\lambda_{\rm{Edd}}=0.8 and 0.4 for DELS J0411-0907 and VDES J0020-3653 respectively. These provide a key comparison for existing estimates from the more uncertain MgII line. We perform quasar-host decomposition using models of the quasars' broad lines to measure the underlying host galaxies. We also discover multiple emission line regions surrounding each of the host galaxies, which are likely companion galaxies undergoing mergers with these hosts. We measure the star formation rates, excitation mechanisms, and dynamical masses of the hosts and companions, measuring the MBH/MdynM_{\rm{BH}}/M_{\rm{dyn}} ratios at high-z using these estimators for the first time. DELS J0411-0907 and VDES J0020-3653 both lie above the local black hole--host mass relation, and are consistent with the existing observations of z6z\gtrsim6 quasar host galaxies with ALMA. We detect ionized outflows in [OIII] and Hβ\beta from both quasars, with mass outflow rates of 58 and 525 M_{\odot}/yr for DELS J0411-0907 and VDES J0020-3653, much larger than their host star formation rates of <33 and <54 M_\odot/yr. This work highlights the exceptional capabilities of the JWST NIRSpec IFU for observing quasars in the early Universe.Comment: 27 pages, 10 figures. Resubmitted to A&A after significant revisions. If you have cited values from our first version, please check this version and update accordingly, as many values have changed slightly thanks to improvements in our analysi

    Gaia-ESO Survey: INTRIGOSS - A New Library of High-resolution Synthetic Spectra

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    We present a high resolution synthetic spectral library, INTRIGOSS, designed for studying FGK stars. The library is based on atmosphere models computed with specified individual element abundances via ATLAS12 code. Normalized SPectra (NSP) and surface Flux SPectra (FSP), in the 4830-5400 A, wavelength range, were computed with the SPECTRUM code. INTRIGOSS uses the solar composition by Grevesse et al. 2007 and four [alpha/Fe] abundance ratios and consists of 15,232 spectra. The synthetic spectra are computed with astrophysical gf-values derived by comparing synthetic predictions with a very high SNR solar spectrum and the UVES-U580 spectra of five cool giants. The validity of the NSPs is assessed by using the UVES-U580 spectra of 2212 stars observed in the framework of the Gaia-ESO Survey and characterized by homogeneous and accurate atmospheric parameter values and by detailed chemical compositions. The greater accuracy of NSPs with respect to spectra from the AMBRE, GES_Grid, PHOENIX, C14, and B17 synthetic spectral libraries is demonstrated by evaluating the consistency of the predictions of the different libraries for the UVES-U580 sample stars. The validity of the FSPs is checked by comparing their prediction with both observed spectral energy distribution and spectral indices. The comparison of FSPs with SEDs derived from ELODIE, INDO--U.S., and MILES libraries indicates that the former reproduce the observed flux distributions within a few percent and without any systematic trend. The good agreement between observational and synthetic Lick/SDSS indices shows that the predicted blanketing of FSPs well reproduces the observed one, thus confirming the reliability of INTRIGOSS FSPs

    Accurate multiple time step in biased molecular simulations

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    Many recently introduced enhanced sampling techniques are based on biasing coarse descriptors (collective variables) of a molecular system on the fly. Sometimes the calculation of such collective variables is expensive and becomes a bottleneck in molecular dynamics simulations. An algorithm to treat smooth biasing forces within a multiple time step framework is here discussed. The implementation is simple and allows a speed up when expensive collective variables are employed. The gain can be substantial when using massively parallel or GPU-based molecular dynamics software. Moreover, a theoretical framework to assess the sampling accuracy is introduced, which can be used to assess the choice of the integration time step in both single and multiple time step biased simulations
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