The effect of distraction on change detection in crowded acoustic scenes

In this series of behavioural experiments we investigated the effect of distraction on the maintenance of acoustic scene information in short-term memory. Stimuli are artificial acoustic ‘scenes’ composed of several (up to twelve) concurrent tone-pip streams (‘sources’). A gap (1000 ms) is inserted partway through the ‘scene’; Changes in the form of an appearance of a new source or disappearance of an existing source, occur after the gap in 50% of the trials. Listeners were instructed to monitor the unfolding ‘soundscapes’ for these events. Distraction was measured by presenting distractor stimuli during the gap. Experiments 1 and 2 used a dual task design where listeners were required to perform a task with varying attentional demands (‘High Demand’ vs. ‘Low Demand’) on brief auditory (Experiment 1a) or visual (Experiment 1b) signals presented during the gap. Experiments 2 and 3 required participants to ignore distractor sounds and focus on the change detection task. Our results demonstrate that the maintenance of scene information in short-term memory is influenced by the availability of attentional and/or processing resources during the gap, and that this dependence appears to be modality specific. We also show that these processes are susceptible to bottom up driven distraction even in situations when the distractors are not novel, but occur on each trial. Change detection performance is systematically linked with the, independently determined, perceptual salience of the distractor sound. The findings also demonstrate that the present task may be a useful objective means for determining relative perceptual salience

Detection of appearing and disappearing objects in complex acoustic scenes.

The ability to detect sudden changes in the environment is critical for survival. Hearing is hypothesized to play a major role in this process by serving as an "early warning device," rapidly directing attention to new events. Here, we investigate listeners' sensitivity to changes in complex acoustic scenes-what makes certain events "pop-out" and grab attention while others remain unnoticed? We use artificial "scenes" populated by multiple pure-tone components, each with a unique frequency and amplitude modulation rate. Importantly, these scenes lack semantic attributes, which may have confounded previous studies, thus allowing us to probe low-level processes involved in auditory change perception. Our results reveal a striking difference between "appear" and "disappear" events. Listeners are remarkably tuned to object appearance: change detection and identification performance are at ceiling; response times are short, with little effect of scene-size, suggesting a pop-out process. In contrast, listeners have difficulty detecting disappearing objects, even in small scenes: performance rapidly deteriorates with growing scene-size; response times are slow, and even when change is detected, the changed component is rarely successfully identified. We also measured change detection performance when a noise or silent gap was inserted at the time of change or when the scene was interrupted by a distractor that occurred at the time of change but did not mask any scene elements. Gaps adversely affected the processing of item appearance but not disappearance. However, distractors reduced both appearance and disappearance detection. Together, our results suggest a role for neural adaptation and sensitivity to transients in the process of auditory change detection, similar to what has been demonstrated for visual change detection. Importantly, listeners consistently performed better for item addition (relative to deletion) across all scene interruptions used, suggesting a robust perceptual representation of item appearance

A rice ABC transporter, OsABCC1, reduces arsenic accumulation in the grain

Arsenic (As) is a chronic poison that causes severe skin lesions and cancer. Rice (Oryza sativa L.) is a major dietary source of As; therefore, reducing As accumulation in the rice grain and thereby diminishing the amount of As that enters the food chain is of critical importance. Here, we report that a member of the Oryza sativa C-type ATP-binding cassette (ABC) transporter (OsABCC) family, OsABCC1, is involved in the detoxification and reduction of As in rice grains. We found that OsABCC1 was expressed in many organs, including the roots, leaves, nodes, peduncle, and rachis. Expression was not affected when plants were exposed to low levels of As but was up-regulated in response to high levels of As. In both the basal nodes and upper nodes, which are connected to the panicle, OsABCC1 was localized to the phloem region of vascular bundles. Furthermore, OsABCC1 was localized to the tonoplast and conferred phytochelatin-dependent As resistance in yeast. Knockout of OsABCC1 in rice resulted in decreased tolerance to As, but did not affect cadmium toxicity. At the reproductive growth stage, the As content was higher in the nodes and in other tissues of wild-type rice than in those of OsABCC1 knockout mutants, but was significantly lower in the grain. Taken together, our results indicate that OsABCC1 limits As transport to the grains by sequestering As in the vacuoles of the phloem companion cells of the nodes in rice.open117318Ysciescopu

Rest-frame Optical Emission Lines in Far-Infrared Selected Galaxies at z<1.7 from the FMOS-COSMOS Survey

We have used FMOS on Subaru to obtain near-infrared spectroscopy of 123 far-infrared selected galaxies in COSMOS and obtain the key rest-frame optical emission lines. This is the largest sample of infrared galaxies with near-infrared spectroscopy at these redshifts. The far-infrared selection results in a sample of galaxies that are massive systems that span a range of metallicities in comparison with previous optically selected surveys, and thus has a higher AGN fraction and better samples the AGN branch. We establish the presence of AGN and starbursts in this sample of (U)LIRGs selected as Herschel-PACS and Spitzer-MIPS detections in two redshift bins (z~0.7 and z~1.5) and test the redshift dependence of diagnostics used to separate AGN from star-formation dominated galaxies. In addition, we construct a low redshift (z~0.1) comparison sample of infrared selected galaxies and find that the evolution from z~1.5 to today is consistent with an evolving AGN selection line and a range of ISM conditions and metallicities from the models of Kewley et al. (2013b). We find that a large fraction of (U)LIRGs are BPT-selected AGN using their new, redshift-dependent classification line. We compare the position of known X-ray detected AGN (67 in total) with the BPT selection and find that the new classification line accurately selects most of these objects (> 70%). Furthermore, we identify 35 new (likely obscured) AGN not selected as such by their X-ray emission. Our results have direct implications for AGN selection at higher redshift with either current (MOSFIRE, KMOS) or future (PFS, MOONS) spectroscopic efforts with near-infrared spectral coverage.Comment: 7 pages, 3 figures, 2 tables. Accepted for publication in The Astrophysical Journal Letter

The FMOS-COSMOS survey of star-forming galaxies at z ~ 1.6. I. H\alpha -based star formation rates and dust extinction

We present the first results from a near-IR spectroscopic survey of the COSMOS field, using the Fiber Multi-Object Spectrograph on the Subaru telescope, designed to characterize the star-forming galaxy population at $1.4<z<1.7$. The high-resolution mode is implemented to detect H$\alpha$ in emission between $1.6{\rm -}1.8 \mathrm{\mu m}$ with $f_{\rm H\alpha}\gtrsim4\times10^{-17}$ erg cm$^{-2}$ s$^{-1}$. Here, we specifically focus on 271 sBzK-selected galaxies that yield a H$\alpha$ detection thus providing a redshift and emission line luminosity to establish the relation between star formation rate and stellar mass. With further $J$-band spectroscopy for 89 of these, the level of dust extinction is assessed by measuring the Balmer decrement using co-added spectra. We find that the extinction ($0.6\lesssim A_\mathrm{H\alpha} \lesssim 2.5$) rises with stellar mass and is elevated at high masses compared to low-redshift galaxies. Using this subset of the spectroscopic sample, we further find that the differential extinction between stellar and nebular emission \hbox{$E_\mathrm{star}(B-V)/E_\mathrm{neb}(B-V)$} is 0.7--0.8, dissimilar to that typically seen at low redshift. After correcting for extinction, we derive an H$\alpha$-based main sequence with a slope ($0.81\pm0.04$) and normalization similar to previous studies at these redshifts.Comment: 6 pages, 4 figures, and 1 table. Published in ApJ Letter

Fabrication of field-effect transistor device with higher fullerene, C₈₈

A fullerene field-effect transistor (FET) device has been fabricated with thin films of C88, and n-channel normally-on depletion-type FET properties have been found in this FET device. The C88 FET exhibited a high mobility, &#956;, of 2.5 x 10-3 cm2 V-1 s-1 at 300 K, in fullerene FETs. The carrier transport showed a thermally-activated hopping transport. The n-channel normally-on FET properties and the hopping transport reflect the small mobility gap and low carrier concentration in the channel region of C88 thin-films.</p

Identifying Ly{\alpha} emitter candidates with Random Forest: learning from galaxies in CANDELS survey

The physical processes which make a galaxy a Lyman Alpha Emitter have been extensively studied for the past 25 years. However, the correlations between physical and morphological properties of galaxies and the strength of the Ly$\alpha$ emission line are still highly debated. Therefore, we investigate the correlations between the rest-frame Ly$\alpha$ equivalent width and stellar mass, star formation rate, dust reddening, metallicity, age, half-light semi-major axis, S\'ersic index and projected axis ratio in a sample of 1578 galaxies in the redshift range $2 \leq z \leq 7.9$ from the GOODS-S, UDS and COSMOS fields. From the large sample of Ly$\alpha$ emitters (LAEs) in the dataset we find that LAEs are typically common main sequence star forming galaxies which show stellar mass $\leq 10^9 \text{M}_{\odot}$, star formation rate $\leq 10^{0.5} \text{M}_{\odot}/\text{yr}$, $E(B-V) \leq 0.2$ and half-light semi-major axis $\leq 1 \text{kpc}$. Building on these findings we develop a new method based on Random Forest (i.e. a Machine Learning classifier) in order to select galaxies which have the highest probability of being Ly$\alpha$ emitters. When applied to a population in the redshift range $z \in [2.5, 4.5]$, our classifier holds a $(80 \pm 2)\%$ accuracy and $(73 \pm 4)\%$ precision. At higher redshifts ($z \in [4.5, 6]$), we obtain a $73\%$ accuracy and a $80\%$ precision. These results highlight it is possible to overcome the current limitations in assembling large samples of LAEs by making informed predictions that can be used for planning future large scale spectroscopic surveys.Comment: Accepted for publication in the 4. Extragalactic astronomy section of Astronomy & Astrophysics, 13 pages, 13 figure

The FMOS-COSMOS survey of star-forming galaxies at z~1.6 III. Survey design, performance, and sample characteristics

We present a spectroscopic survey of galaxies in the COSMOS field using the Fiber Multi-Object Spectrograph (FMOS), a near-infrared instrument on the Subaru Telescope. Our survey is specifically designed to detect the Halpha emission line that falls within the H-band (1.6-1.8 um) spectroscopic window from star-forming galaxies with 1.4 ~10^10 Msolar. With the high multiplex capability of FMOS, it is now feasible to construct samples of over one thousand galaxies having spectroscopic redshifts at epochs that were previously challenging. The high-resolution mode (R~2600) effectively separates Halpha and [NII]6585 thus enabling studies of the gas-phase metallicity and photoionization state of the interstellar medium. The primary aim of our program is to establish how star formation depends on stellar mass and environment, both recognized as drivers of galaxy evolution at lower redshifts. In addition to the main galaxy sample, our target selection places priority on those detected in the far-infrared by Herschel/PACS to assess the level of obscured star formation and investigate, in detail, outliers from the star formation rate - stellar mass relation. Galaxies with Halpha detections are followed up with FMOS observations at shorter wavelengths using the J-long (1.11-1.35 um) grating to detect Hbeta and [OIII]5008 that provides an assessment of extinction required to measure star formation rates not hampered by dust, and an indication of embedded Active Galactic Nuclei. With 460 redshifts measured from 1153 spectra, we assess the performance of the instrument with respect to achieving our goals, discuss inherent biases in the sample, and detail the emission-line properties. Our higher-level data products, including catalogs and spectra, are available to the community.Comment: 26 pages, Updated version resubmitted to ApJSS; Data products and catalogs are now available at http://member.ipmu.jp/fmos-cosmos

The FMOS-COSMOS survey of star-forming galaxies at z~1.6. IV: Excitation state and chemical enrichment of the interstellar medium

We investigate the physical conditions of ionized gas in high-z star-forming galaxies using diagnostic diagrams based on the rest-frame optical emission lines. The sample consists of 701 galaxies with an Ha detection at $1.4\lesssim z\lesssim1.7$, from the FMOS-COSMOS survey, that represent the normal star-forming population over the stellar mass range $10^{9.6} \lesssim M_\ast/M_\odot \lesssim 10^{11.6}$ with those at $M_\ast>10^{11}~M_\odot$ being well sampled. We confirm an offset of the average location of star-forming galaxies in the BPT diagram ([OIII]/Hb vs. [NII]/Ha), primarily towards higher [OIII]/Hb, compared with local galaxies. Based on the [SII] ratio, we measure an electron density ($n_e=220^{+170}_{-130}~\mathrm{cm^{-3}}$), that is higher than that of local galaxies. Based on comparisons to theoretical models, we argue that changes in emission-line ratios, including the offset in the BPT diagram, are caused by a higher ionization parameter both at fixed stellar mass and at fixed metallicity with additional contributions from a higher gas density and possibly a hardening of the ionizing radiation field. Ionization due to AGNs is ruled out as assessed with Chandra. As a consequence, we revisit the mass-metallicity relation using [NII]/Ha and a new calibration including [NII]/[SII] as recently introduced by Dopita et al. Consistent with our previous results, the most massive galaxies ($M_\ast\gtrsim10^{11}~M_\odot$) are fully enriched, while those at lower masses have metallicities lower than local galaxies. Finally, we demonstrate that the stellar masses, metallicities and star formation rates of the FMOS sample are well fit with a physically-motivated model for the chemical evolution of star-forming galaxies.Comment: 38 pages; Accepted for publication in Ap

Predicting emission line fluxes and number counts of distant galaxies for cosmological surveys

open12siWe estimate the number counts of line emitters at high redshift and their evolution with cosmic time based on a combination of photometry and spectroscopy. We predict the H α, H β, [O II], and [O III] line fluxes for more than 35 000 galaxies down to stellar masses of ∼109 M⊙ in the COSMOS and GOODS-S fields, applying standard conversions and exploiting the spectroscopic coverage of the FMOS-COSMOS survey at z ∼ 1.55 to calibrate the predictions. We calculate the number counts of H α, [O II], and [O III] emitters down to fluxes of 1 × 10-17 erg cm-2 s-1 in the range 1.4 &lt; z &lt; 1.8 covered by the FMOS-COSMOS survey. We model the time evolution of the differential and cumulative H α counts, steeply declining at the brightest fluxes. We expect ∼9300-9700 and ∼2300-2900 galaxies deg-2 for fluxes ≥1 × 10-16 and ≥2 × 10-16 erg cm-2 s-1 over the range of 0.9 &lt; z &lt; 1.8. We show that the observed evolution of the main sequence of galaxies with redshift is enough to reproduce the observed counts variation at 0.2 &lt; z &lt; 2.5. We characterize the physical properties of the H α emitters with fluxes ≥2 × 10-16 erg cm-2 s-1 including their stellar masses, UV sizes, [N II]/H α ratios and H α equivalent widths. An aperture of R ∼ Re ∼ 0.5 arcsec maximizes the signal-to-noise ratio for a detection, whilst causing a factor of ∼2 × flux losses, influencing the recoverable number counts, if neglected. Our approach, based on deep and large photometric data sets, reduces the uncertainties on the number counts due to the selection and spectroscopic samplings whilst exploring low fluxes. We publicly release the line flux predictions for the explored photometric samples.mixedopenValentino, F.; Daddi, E.; Silverman, J. D.; Puglisi, A.; Kashino, D.; Renzini, A.; Cimatti, A.; Pozzetti, L.; Rodighiero, G.; Pannella, M.; Gobat, R.; Zamorani, G.Valentino, F.; Daddi, E.; Silverman, J. D.; Puglisi, A.; Kashino, D.; Renzini, A.; Cimatti, A.; Pozzetti, L.; Rodighiero, G.; Pannella, M.; Gobat, R.; Zamorani, G