The assembly of "normal" galaxies at z=7 probed by ALMA

We report new deep ALMA observations aimed at investigating the [CII]158um line and continuum emission in three spectroscopically confirmed Lyman Break Galaxies at 6.8<z<7.1, i.e. well within the re-ionization epoch. With Star Formation Rates of SFR ~ 5-15 Msun/yr these systems are much more representative of the high-z galaxy population than other systems targeted in the past by millimeter observations. For the galaxy with the deepest observation we detect [CII] emission at redshift z=7.107, fully consistent with the Lyalpha redshift, but spatially offset by 0.7" (4 kpc) from the optical emission. At the location of the optical emission, tracing both the Lyalpha line and the far-UV continuum, no [CII] emission is detected in any of the three galaxies, with 3sigma upper limits significantly lower than the [CII] emission observed in lower reshift galaxies. These results suggest that molecular clouds in the central parts of primordial galaxies are rapidly disrupted by stellar feedback. As a result, [CII] emission mostly arises from more external accreting/satellite clumps of neutral gas. These findings are in agreement with recent models of galaxy formation. Thermal far-infrared continuum is not detected in any of the three galaxies. However, the upper limits on the infrared-to-UV emission ratio do not exceed those derived in metal- and dust-poor galaxies.Comment: 15 pages, 9 figures, MNRAS in press, replaced with accepted versio

JWST/NIRSpec Measurements of the Relationships Between Nebular Emission-line Ratios and Stellar Mass at z~3-6

We analyze the rest-optical emission-line ratios of star-forming galaxies at 2.7<=z<6.5 drawn from the Cosmic Evolution Early Release Science (CEERS) Survey, and their relationships with stellar mass (M_*). Our analysis includes both line ratios based on the [NII]6583 feature -- [NII]6583/Ha, ([OIII]5007/Hb)/([NII]6583/Ha) (O3N2), and [NII]6583/[OII]3727 -- and those those featuring alpha elements -- [OIII]5007/Hb, [OIII]5007/[OII]3727 (O_32), ([OIII]4959,5007+[OII]3727)/Hb (R_23), and [NeIII]3869/[OII]3727. Given the typical flux levels of [NII]6583 and [NeIII]3869, which are undetected in the majority of individual CEERS galaxies at 2.7<=z<6.5, we construct composite spectra in bins of M_* and redshift. Using these composite spectra, we compare the relationships between emission-line ratios and M_* at 2.7<=z<6.5 with those observed at lower redshift. While there is significant evolution towards higher excitation (e.g., higher [OIII]5007/Hb, O_32, O3N2), and weaker nitrogen emission (e.g., lower [NII]6583/Ha and [NII]6583/[OII]3727) between z~0 and z~3, we find in most cases that there is no significant evolution in the relationship between line ratio and M_* beyond z~3. The [NeIII]3869/[OII]3727 ratio is anomalous in showing evidence for significant elevation at 4.0<=z<6.5 at fixed mass, relative to z~3.3. Collectively, however, our empirical results suggest that there is no significant evolution in the mass-metallicity relationship at 2.7<=z<6.5. Representative galaxy samples and metallicity calibrations based on existing and upcoming JWST/NIRSpec observations will be required to translate these empirical scaling relations into ones tracing chemical enrichment and gas cycling, and distinguish among the descriptions of star-formation feedback in simulations of galaxy formation at z>3.Comment: 10 pages, 4 figures, ApJL, in pres

JWST/NIRSpec Balmer-line Measurements of Star Formation and Dust Attenuation at z~3-6

We present an analysis of the star-formation rates (SFRs) and dust attenuation properties of star-forming galaxies at $2.7\leq z<6.5$ drawn from the Cosmic Evolution Early Release Science (CEERS) Survey. Our analysis is based on {\it JWST}/NIRSpec Micro-Shutter Assembly (MSA) $R\sim1000$ spectroscopic observations covering approximately $1-5$$\mu$m. Our primary rest-frame optical spectroscopic measurements are H$\alpha$/H$\beta$ Balmer decrements, which we use as an indicator of nebular dust attenuation. In turn, we use Balmer decrements to obtain dust-corrected H$\alpha$-based SFRs (i.e., SFR(H$\alpha$)). We construct the relationship between SFR(H$\alpha$) and stellar mass ($M_*$) in three bins of redshift ($2.7\leq z< 4.0$, $4.0\leq z< 5.0$, and $5.0\leq z<6.5$), which represents the first time the star-forming main sequence has been traced at these redshifts using direct spectroscopic measurements of Balmer emission as a proxy for SFR. In tracing the relationship between SFR(H$\alpha$) and $M_*$ back to such early times ($z>3$), it is essential to use a conversion factor between H$\alpha$ and SFR that accounts for the subsolar metallicity prevalent among distant galaxies. We also use measured Balmer decrements to investigate the relationship between dust attenuation and stellar mass out to $z\sim6$. The lack of significant redshift evolution in attenuation at fixed stellar mass, previously confirmed using Balmer decrements out to $z\sim2.3$, appears to hold out to $z\sim 6.5$. Given the rapidly evolving gas, dust, and metal content of star-forming galaxies at fixed mass, this lack of significant evolution in attenuation provides an ongoing challenge to explain.Comment: 9 pages, 4 figures, ApJ, in pres

Neural responses to facial and vocal expressions of fear and disgust

Neuropsychological studies report more impaired responses to facial expressions of fear than disgust in people with amygdala lesions, and vice versa in people with Huntington's disease. Experiments using functional magnetic resonance imaging (fMRI) have confirmed the role of the amygdala in the response to fearful faces and have implicated the anterior insula in the response to facial expressions of disgust. We used fMRI to extend these studies to the perception of fear and disgust from both facial and vocal expressions. Consistent with neuropsychological findings, both types of fearful stimuli activated the amygdala. Facial expressions of disgust activated the anterior insula and the caudate-putamen; vocal expressions of disgust did not significantly activate either of these regions. All four types of stimuli activated the superior temporal gyrus. Our findings therefore (i) support the differential localization of the neural substrates of fear and disgust; (ii) confirm the involvement of the amygdala in the emotion of fear, whether evoked by facial or vocal expressions; (iii) confirm the involvement of the anterior insula and the striatum in reactions to facial expressions of disgust; and (iv) suggest a possible general role for the perception of emotional expressions for the superior temporal gyrus

Neural correlates of visuospatial working memory in the ‘at-risk mental state’

Background. Impaired spatial working memory (SWM) is a robust feature of schizophrenia and has been linked to the risk of developing psychosis in people with an at-risk mental state (ARMS). We used functional magnetic resonance imaging (fMRI) to examine the neural substrate of SWM in the ARMS and in patients who had just developed schizophrenia. Method. fMRI was used to study 17 patients with an ARMS, 10 patients with a first episode of psychosis and 15 agematched healthy comparison subjects. The blood oxygen level-dependent (BOLD) response was measured while subjects performed an object–location paired-associate memory task, with experimental manipulation of mnemonic load. Results. In all groups, increasing mnemonic load was associated with activation in the medial frontal and medial posterior parietal cortex. Significant between-group differences in activation were evident in a cluster spanning the medial frontal cortex and right precuneus, with the ARMS groups showing less activation than controls but greater activation than first-episode psychosis (FEP) patients. These group differences were more evident at the most demanding levels of the task than at the easy level. In all groups, task performance improved with repetition of the conditions. However, there was a significant group difference in the response of the right precuneus across repeated trials, with an attenuation of activation in controls but increased activation in FEP and little change in the ARMS. Conclusions. Abnormal neural activity in the medial frontal cortex and posterior parietal cortex during an SWM task may be a neural correlate of increased vulnerability to psychosis

Metal Hydrides Form Halogen Bonds: Measurement of Energetics of Binding

The formation of halogen bonds from iodopentafluorobenzene and 1-iodoperfluorohexane to a series of bis(η5-cyclopentadienyl)metal hydrides (Cp2TaH3, 1; Cp2MH2, M = Mo, 2, M = W, 3; Cp2ReH, 4; Cp2Ta(H)CO, 5; Cp = η5-cyclopentadienyl) is demonstrated by 1H NMR spectroscopy. Interaction enthalpies and entropies for complex 1 with C6F5I and C6F13I are reported (ΔH° = −10.9 ± 0.4 and −11.8 ± 0.3 kJ/mol; ΔS° = −38 ± 2 and −34 ± 2 J/(mol·K), respectively) and found to be stronger than those for 1 with the hydrogen-bond donor indole (ΔH° = −7.3 ± 0.1 kJ/mol, ΔS° = −24 ± 1 J/(mol·K)). For the more reactive complexes 2–5, measurements are limited to determination of their low-temperature (212 K) association constants with C6F5I as 2.9 ± 0.2, 2.5 ± 0.1, <1.5, and 12.5 ± 0.3 M–1, respectively

BRS 328 - Double haploid bread wheat cultivar.

The wheat cultivar 'BRS 328' was developed by Embrapa from a cross between KleinH3394 and PF 990744. The pre-harvest sprouting resistance of 'BRS 328' is good and the grain yieldhigh. It is classified as bread wheat cultivar in all regions where it is recommended for cultivation

Estabilidade genética em genótipos de trigo estimada pela viabilidade polínica.

Objetivou-se estimar a estabilidade genética de 170 genótipos de trigo por meio da viabilidade polínica. Os genótipos foram provenientes do Banco Ativo de Germoplasma e dos ensaios de Valor e Cultivo e Uso da Embrapa Trigo, no período 2011 a 2013. Foram coletadas espigas em pré-antese, fixadas em Carnoy 3:1 e armazenadas em álcool 70%. As lâminas citológicas foram preparadas pela técnica de ?Squash? e corante carmin acético 1%. As análises foram em microscopia ótica, com três repetições e 1500 células/genótipo. Os resultados indicaram que 98% dos genótipos apresentaram viabilidade polínica acima de 95%, identificados como estáveis. Quanto às anormalidades, foram observados grãos de pólens vazios na maioria dos genótipos, mas com incidência muito baixas, não significativas

The Grism Lens-Amplified Survey from Space (GLASS). XII. Spatially Resolved Galaxy Star Formation Histories and True Evolutionary Paths at z > 1

Modern data empower observers to describe galaxies as the spatially and biographically complex objects they are. We illustrate this through case studies of four, $z\sim1.3$ systems based on deep, spatially resolved, 17-band + G102 + G141 Hubble Space Telescope grism spectrophotometry. Using full spectrum rest-UV/-optical continuum fitting, we characterize these galaxies' observed $\sim$kpc-scale structures and star formation rates (SFRs) and reconstruct their history over the age of the universe. The sample's diversity---passive to vigorously starforming; stellar masses $\log M_*/M_\odot=10.5$ to $11.2$---enables us to draw spatio-temporal inferences relevant to key areas of parameter space (Milky Way- to super-Andromeda-mass progenitors). Specifically, we find signs that bulge mass-fractions ($B/T$) and SF history shapes/spatial uniformity are linked, such that higher $B/T$s correlate with "inside-out growth" and central specific SFRs that peaked above the global average for all starforming galaxies at that epoch. Conversely, the system with the lowest $B/T$ had a flat, spatially uniform SFH with normal peak activity. Both findings are consistent with models positing a feedback-driven connection between bulge formation and the switch from rising to falling SFRs ("quenching"). While sample size forces this conclusion to remain tentative, this work provides a proof-of-concept for future efforts to refine or refute it: JWST, WFIRST, and the 30-m class telescopes will routinely produce data amenable to this and more sophisticated analyses. These samples---spanning representative mass, redshift, SFR, and environmental regimes---will be ripe for converting into thousands of sub-galactic-scale empirical windows on what individual systems actually looked like in the past, ushering in a new dialog between observation and theory.Comment: 18 pp, 15 figs, 3 tables (main text); 5 pp, 5 figs, 1 table (appendix); Submitted to AAS Journals 1 October 201