Interaction between hydrodynamics and seagrass canopy structure: Spatially explicit effects on ammonium uptake rates

The hypotheses that (1) different seagrass morphologies may facilitate different nutrient uptake rates under similar hydrodynamic forcing and (2) this effect on nutrient uptake rates is spatially explicit, with the highest uptake rates at edges of patches, where currents and turbulence are highest, were examined under unidirectional flow conditions.We thank Jos van Soelen, Bas Koutstaal, and Louie Haazen for invaluable technical assistance. In addition, we are grateful to Britta Gribsholt, Bart Veuger, Miguel Bernal, Juan Jose Vergara, and Alfredo Izquirdo for helpful discussion. In addition, we thank Josef D. Ackerman and the anonymous reviewers for comments that greatly improved the manuscript. This work and the first author were supported by an EU Marie Curie host fellowship for transfer of knowledge, MTKD-CT-2004-509254, and the Spanish national project EVAMARIA, CTM2005-00395/MAR. F.G.B. holds an EU Marie Curie individual fellowship, MEIF-CT-2005-515071. This is publication 4251 of the Netherlands Institute of Ecology (NIOO-KNAW)

Exploring the evolutionary paths of the most massive galaxies since z~2

We use Spitzer MIPS data from the FIDEL Legacy Project in the Extended Groth Strip to analyze the stellar mass assembly of massive (M>10^11 M_sun) galaxies at z<2 as a function of structural parameters. We find 24 micron emission for more than 85% of the massive galaxies morphologically classified as disks, and for more than 57% of the massive systems morphologically classified as spheroids at any redshift, with about 8% of sources harboring a bright X-ray and/or infrared emitting AGN. More noticeably, 60% of all compact massive galaxies at z=1-2 are detected at 24 micron, even when rest-frame optical colors reveal that they are dead and evolving passively. For spheroid-like galaxies at a given stellar mass, the sizes of MIPS non-detections are smaller by a factor of 1.2 in comparison with IR-bright sources. We find that disk-like massive galaxies present specific SFRs ranging from 0.04 to 0.2 Gyr^-1 at z<1 (SFRs ranging from 1 to 10 M_sun/yr), typically a factor of 3-6 higher than massive spheroid-like objects in the same redshift range. At z>1, and more pronouncedly at z>1.3, the median specific SFRs of the disks and spheroids detected by MIPS are very similar, ranging from 0.1 to 1 Gyr^-1 (SFR=10-200 M_sun/yr). We estimate that massive spheroid-like galaxies may have doubled (at the most) their stellar mass from star-forming events at z<2: less than 20% mass increase at 1.7<z<2.0, up to 40% more at 1.1<z<1.7, and less than 20% additional increase at z<1. Disk-like galaxies may have tripled (at the most) their stellar mass at z<2 from star formation alone: up to 40% mass increase at 1.7<z<2.0, and less than 180% additional increase below z=1.7 occurred at a steady rate.Comment: Accepted for publication in ApJ; 10 pages, 5 figures, 1 tabl

Investigating the physical properties of galaxies in the Epoch of Reionization with MIRI/JWST spectroscopy

The James Webb Space Telescope (JWST) will provide deep imaging and spectroscopy for sources at redshifts above 6, covering the entire Epoch of Reionization (EoR, 6 5) EoR sources at redshifts above 7 with intrinsic star formation rates (SFR) of more than 2 Mꙩ yr^(−1), and stellar masses above 4–9 × 10^(7) Mꙩ. These limits cover the upper end of the SFR and stellar mass distribution at those redshifts, representing ∼6% and ∼1% of the predicted FIRSTLIGHT population at the 6.5–7.5 and 7.5–8.5 redshift ranges, respectively. In addition, the paper presents realistic MRS simulated observations of the expected rest-frame optical and near-infrared spectra for some spectroscopically confirmed EoR sources recently detected by ALMA as [OIII]88 µm emitters. The MRS simulated spectra cover a wide range of low metallicities from about 0.2–0.02 Zꙩ, and different [OIII]88 µm/[OIII]0.5007 µm line ratios. The simulated 10 ks MRS spectra show S/N in the range of 5–90 for Hβ, [OIII]0.4959,0.5007 µm, Hα and HeI1.083 µm emission lines of the currently highest spectroscopically confirmed EoR (lensed) source MACS1149-JD1 at a redshift of 9.11, independent of metallicity. In addition, deep 40 ksec simulated spectra of the luminous merger candidate B14-65666 at 7.15 shows the MRS capabilities of detecting, or putting strong upper limits on, the weak [NII]0.6584 µm, [SII]0.6717,0.6731 µm, and [SIII]0.9069,0.9532 µm emission lines. These observations will provide the opportunity of deriving accurate metallicities in bright EoR sources using the full range of rest-frame optical emission lines up to 1 µm. In summary, MRS will enable the detailed study of key physical properties such as internal extinction, instantaneous star formation, hardness of the ionizing continuum, and metallicity in bright (intrinsic or lensed) EoR sources

Uv-to-fir analysis of spitzer/irac sources in the extended groth strip i: Multi-wavelength photometry and spectral energy distributions

We present an IRAC 3.6+4.5 microns selected catalog in the Extended Groth Strip (EGS) containing photometry from the ultraviolet to the far-infrared and stellar parameters derived from the analysis of the multi-wavelength data. In this paper, we describe the method used to build coherent spectral energy distributions (SEDs) for all the sources. In a companion paper, we analyze those SEDs to obtain robust estimations of stellar parameters such as photometric redshifts, stellar masses, and star formation rates. The catalog comprises 76,936 sources with [3.6]<23.75 mag (85% completeness level of the IRAC survey in the EGS) over 0.48 square degrees. For approximately 16% of this sample, we are able to deconvolve the IRAC data to obtain robust fluxes for the multiple counterparts found in ground-based optical images. Typically, the SEDs of the IRAC sources in our catalog count with more than 15 photometric data points, spanning from the UV to the FIR. Approximately 95% and 90% of all IRAC sources are detected in the deepest optical and near-infrared bands. Only 10% of the sources have optical spectroscopy and redshift estimations. Almost 20% and 2% of the sources are detected by MIPS at 24 and 70 microns, respectively. We also cross-correlate our catalog with public X-ray and radio catalogs. Finally, we present the Rainbow Navigator public web-interface utility designed to browse all the data products resulting from this work, including images, spectra, photometry, and stellar parameters.Comment: 28 pages, 12 figures, Accepted for publication in ApJ. Access the Rainbow Database at: http://rainbowx.fis.ucm.e

Integral field spectroscopy of H II region complexes: the outer disc of NGC 6946

This is an electronic version of an article published in Monthly Notices of the Royal Astronomical Society. García-Benito, R., Díaz, A., Hägele, G.F., Pérez-Montero, E., López, J., Vílchez, J.M., Pérez, E., Terlevich, E., Terlevich, R., D. Rosa-González. Integral field spectroscopy of H II region complexes: the outer disc of NGC 6946. Monthly Notices of the Royal Astronomical Society 408 (2010): 2234-225

Computer-Based Cognitive Training Improves Brain Functional Connectivity in the Attentional Networks: A Study With Primary School-Aged Children

We have shown that a computer-based program that trains schoolchildren in cognitive tasks that mainly tap working memory (WM), implemented by teachers and integrated into school routine, improved cognitive and academic skills compared with an active control group. Concretely, improvements were observed in inhibition skills, non-verbal IQ, mathematics and reading skills. Here, we focus on a subsample from the overarching study who volunteered to be scanned using a resting state fMRI protocol before and 6-month after training. This sample reproduced the aforementioned behavioral effects, and brain functional connectivity changes were observed within the attentional networks (ATN), linked to improvements in inhibitory control. Findings showed stronger relationships between inhibitory control scores and functional connectivity in a right middle frontal gyrus (MFG) cluster in trained children compared to children from the control group. Seed-based analyses revealed that connectivity between the r-MFG and homolateral parietal and superior temporal areas were more strongly related to inhibitory control in trained children compared to the control group. These findings highlight the relevance of computer-based cognitive training, integrated in real-life school environments, in boosting cognitive/academic performance and brain functional connectivity

Integral field spectroscopy of HII region complexes: The outer disc of NGC-6946

Integral field spectroscopy obtained with the Potsdam Multi-Aperture Spectrophotometer Fiber Package (PPak) and the 3.5-m telescope at the Calar Alto Observatory has been used to study an outer H ii region complex in the well-studied galaxy NGC-6946. This technique provides detailed maps of the region in different emission lines, yielding spatially resolved information about the physical properties of the gas. The configuration was chosen to cover the whole spectrum from 3600 up to 10-000-Å, allowing the measurement of the near-infrared [S-iii] lines. We selected four luminous knots to perform a detailed integrated spectroscopic analysis of these structures and of the whole PPak field of view (FOV). For all the knots the electron density has been found to be very similar and below 100 cm-3. The [O-iii] electron temperature was measured in knots A, B, C and in the integrated PPak field, and was found to be around 8000 K. The temperatures of [O-ii] and [S-iii] were estimated in the four cases. The elemental abundances computed from the 'direct method' are typical of high-metallicity disc H-ii regions, with a mean value of 12+log(O/H) = 8.65, comparable to what has been found in this galaxy by other authors for regions at similar galactocentric distance. Therefore a remarkable abundance uniformity is found despite the different excitations found throughout the nebula. However, due to the quality of the data, the electron temperatures and metallicities obtained have associated errors comparable to the typical dispersion found in empirical calibrations.Wolf-Rayet (WR) features have been detected in three of the knots, leading to a derived total number of WR stars of 125, 22 and 5 for knots A, C and B, respectively. The ratios of the numbers of WR to O stars are consistent with the prediction of Starburst99 for individual bursts with an age about 4-Myr. Knot D, with no WR features, shows weak Hα emission, low excitation and the lowest Hβ equivalent width, all of which points to a more evolved state.The integrated spectrum of the whole PPak FOV shows high excitation and a relatively evolved age that does not correspond to the individual knot evolutionary stages. Some effects associated with the loss of spatial resolution are also evidenced by the higher ionizing temperature that is deduced from the η' parameter measured in the integrated PPak spectrum with respect to that of the individual knots.Facultad de Ciencias Astronómicas y Geofísica

Influencia del uso de una muestra de referencia interna y del mezclado de heces sobre la reproducibilidad de la producción de gas in vitro

A P. maximum homogeneous sample with different average gas volumes accumulated through time was used as a reference to evaluate the influence of an inner reference sample and a feces mixture upon gas in vitro production generating capacity. Effectiveness assessment of this kind of correction was performed by studying A. bilimekii, H. brasiletto, and A. pennatula samples. This correction consisted in multiplying the sample hourly accumulated volume by the average volume ratio between the standard and the studied samples. Such a correction improved generating capacity in every case; however, variation coefficients from highly different feces mixtures were over 100 % indicating effectiveness limitations. Concerning the assessment of feces mixture influence, S.officinarum samples, two macroscopically different inocula, and a mixture of both were used. Variability was higher when using non-mixed feces compared to mixed ones, but variation coefficient levels for inocula remained within a 5 % range in some cases. Further work is needed to find out suitable indicators to control inoculum power.Con el objetivo de evaluar la influencia del uso de una muestra de referencia interna y del mezclado de las heces sobre la reproducibilidad de la producción de gas in vitro se utilizó como referencia una muestra homogénea de P. maximum de la que se conocen los promedios de gas acumulado en los diferentes tiempos. Para evaluar la efectividad de este tipo de corrección se estudiaron muestras de A. bilimekii, H. brasiletto y A. pennatula. La corrección hecha consistió en multiplicar el volumen acumulado por las muestras, para cada hora, por la relación entre el volumen promedio de la muestra patrón y la estudiada. La corrección empleada mejora en todos los casos la reproducibilidad, no obstante, los coeficientes de variación (CV) obtenidos, cuando se trata con heces muy diferentes, son superiores al 10 %, por lo que la efectividad tiene sus límites. Para evaluar la influencia del mezclado de heces se utilizaron muestras de S. officinarum, dos inóculos macroscópicamente diferentes, y la mezcla de ambos. La variabilidad cuando se usan heces sin mezclar es mayor que cuando se mezclan, pero no siempre se logra disminuir los CV entre inóculos a niveles no mayores al 5 %. Se recomienda trabajar en la búsqueda de indicadores para controlar la fuerza del inócul