Abstract
We report the discovery of a 10 comoving megaparsec (cMpc)-scale structure traced by massive submillimeter galaxies (SMGs) at
z
∼ 4.6. These galaxies are selected from an emission line ...search of ALMA Band 7 observations targeting 184 luminous submillimeter sources (
S
850
μ
m
≥ 6.2 mJy) across 1.6 degrees
2
in the COSMOS field. We identify four C
ii
emitting SMGs and two probable C
ii
emitting SMG candidates at
z
= 4.60–4.64 with velocity-integrated signal-to-noise ratio of S/N > 8. Four of the six emitters are near-infrared blank SMGs. After excluding one SMG whose emission line is falling at the edge of the spectral window, all galaxies show clear velocity gradients along the major axes that are consistent with rotating gas disks. The estimated rotation velocities of the disks are 330–550 km s
−1
and the inferred host dark-matter halo masses are ∼2–8 × 10
12
M
⊙
. From their estimated halo masses and C
ii
luminosity function, we suggest that these galaxies have a high (50%–100%) duty cycle and high (∼0.1) baryon conversion efficiency (SFR relative to baryon accretion rate), and that they contribute ≃2% to the total star formation rate density at
z
= 4.6. These SMGs are concentrated within just 0.3% of the full survey volume, suggesting they are strongly clustered. The extent of this structure and the individual halo masses suggest that these SMGs will likely evolve into members of a ∼10
15
M
⊙
cluster at
z
= 0. This survey reveals a synchronized dusty starburst in massive halos at
z
> 4, which could be driven by mergers or fed by smooth gas accretion.
Galaxies in the early Universe that are bright at submillimetre wavelengths (submillimetre-bright galaxies) are forming stars at a rate roughly 1,000 times higher than the Milky Way. A large fraction ...of the new stars form in the central kiloparsec of the galaxy
, a region that is comparable in size to the massive, quiescent galaxies found at the peak of cosmic star-formation history
and the cores of present-day giant elliptical galaxies. The physical and kinematic properties inside these compact starburst cores are poorly understood because probing them at relevant spatial scales requires extremely high angular resolution. Here we report observations with a linear resolution of 550 parsecs of gas and dust in an unlensed, submillimetre-bright galaxy at a redshift of z = 4.3, when the Universe was less than two billion years old. We resolve the spatial and kinematic structure of the molecular gas inside the heavily dust-obscured core and show that the underlying gas disk is clumpy and rotationally supported (that is, its rotation velocity is larger than the velocity dispersion). Our analysis of the molecular gas mass per unit area suggests that the starburst disk is gravitationally unstable, which implies that the self-gravity of the gas is stronger than the differential rotation of the disk and the internal pressure due to stellar-radiation feedback. As a result of the gravitational instability in the disk, the molecular gas would be consumed by star formation on a timescale of 100 million years, which is comparable to gas depletion times in merging starburst galaxies
.
Tm3+/Yb3+ doped CaF2, SrF2, and cubic phase NaYF4 nanoparticles dispersed as colloids in water (H2O and D2O) or saline solutions have been directly prepared by a one-step hydrothermal technique, ...using citrate anions as capping agents, without the need for any postsynthesis reaction. The size monodispersed nanoparticles are directly dispersed in water. Comparison of the upconversion emissions at 800 nm (Tm3+ ions) among the CaF2, SrF2, and NaYF4 hosts indicates that the SrF2 host leads to the highest emission intensity, 2 orders of magnitude higher than the NaYF4 one. Alkali ions (Na+ or K+) counter cations of the citrate salts used as precursors can enter the fluoride host crystals as charge compensators and strongly influence the spectroscopic properties of the lanthanide ions. The Tm3+/Yb3+ doped SrF2 nanoparticles dispersed in a 0.4 g/L concentration solution show detectable upconversion with laser excitation intensities as low as 1 W/cm2.
This paper reports on the results of an experiment involving a wearable sensorimotor enhancer intended to improve tactile sensitivity in human fingertips. As briefly exposing tactile receptors to ...subsensory vibration is known to enhance tactile sensitivity thanks to a phenomenon called stochastic resonance in the somatosensory system, applying white-noise vibration to a fingertip is expected to improve the sense of touch and associated motor skills. Against such a background, a prototype of a wearable device called a sensorimotor enhancer is proposed here. The device is attached to the radial side of the fingertip and stimulates tactile receptors by applying vibration from a lead zirconate titanate piezoelectric stack actuator. This design keeps the palmar region free, thereby helping to maintain the wearer's manipulative ability. Sensory and motor tests involving 11 human subjects were conducted to determine the efficacy of the device, and the results confirmed its usefulness.
Epithelial splicing regulatory protein 1 (ESRP1) binds the FGFR-2 auxiliary cis-element ISE/ISS-3, located in the intron between exon IIIb and IIIc, and primarily promotes FGFR-2 IIIb expression. ...Here we assessed the role of ESRP1 in pancreatic ductal adenocarcinoma (PDAC). Immunohistochemical analysis was performed using anti-ESRP1, FGFR-2 IIIb and FGFR-2 IIIc antibodies in 123 PDAC cases. ESRP1 expression vector and small interference RNA (siRNA) targeting ESRP1 were transfected into human PDAC cells, and cell growth, migration and invasion were analyzed. In vivo heterotopic and orthotopic implantations using ESRP1 overexpression clones were performed and effects on pancreatic tumor volumes and hepatic and pulmonary metastases determined. ESRP1 immunoreactivity was strong in the nuclei of cancer cells in well-to-moderately differentiated PDACs but weak in poorly differentiated cancers. Well-to-moderately differentiated cancers also exhibited high FGFR-2 IIIb and low FGFR-2 IIIc expression, whereas this ratio was reversed in the poorly differentiated cancers. Increased ESRP1 expression was associated with longer survival in comparison with low ESRP1 expression, and PANC-1 cells engineered to express ESRP1 exhibited increased FGFR-2 IIIb expression and decreased migration and invasion in vitro, whereas ESRP1 siRNA-transfected KLM-1 cells exhibited increased FGFR-2 IIIc expression and increased cell growth, migration and invasion. In vivo, ESRP1-overexpressing clones formed significantly fewer liver metastases as compared with control clones. ESRP1 regulates the expression pattern of FGFR-2 isoforms, attenuates cell growth, migration, invasion and metastasis, and is a favorable prognostic factor in PDAC. Therefore, devising mechanisms to upregulate ESRP1 may exert a beneficial therapeutic effect in PDAC.
The objective of this study is to investigate the emission mechanism of radiophotoluminescence (RPL) in the Ag+-doped phosphate glass (glass dosimeter), which is now used as individual radiation ...dosimeter, because the emission mechanism of RPL in glass dosimeter has been not fully understood. We have investigated the assignments and characteristics of the X-ray induced color centers in the Ag+-doped phosphate glass up to now (Miyamoto et al., 2010). Optical properties such as optical absorption spectra related with alpha-particles and X-rays irradiation were measured for commercially available glass dosimeter.
In this study optical properties such as optical absorption spectrum as a function of alpha-particles and X-rays irradiation were measured for commercially available glass dosimeter. Comparison of the RPL in Ag+-doped phosphate glass irradiated with alpha-particles and X-rays is discussed.
•A Yellow and blue emission are included in the RPL of Ag+-doped phosphate glass.•The ratio of yellow and blue emission was different between alpha and X-ray irradiation.•RPL emission intensity increased in an atmosphere below room temperature.
Piezoelectric stack actuators have the advantages of zero backlash and no acoustic noise, but their stroke is too small to actuate robotic links directly. Because the force available is often more ...than the required, the stroke of the piezoelectric stack can be amplified by a compliant mechanism at the expense of force. It is not always clear what the geometry of this compliant mechanism should be. Compliant mechanisms have parallels in biology in that they describe two-way interactions between the actuator and the environment. In this paper, we employ the concept of a two-port network model from circuit theory to describe this two-way interaction and present a method to obtain each element of the two-port model as an analytical function of physical geometric parameters for a wide class of geometries. This method makes use of Castigliano's theorem and Euler-Bernoulli linearly elastic beam theory. To our knowledge, this is the first two-port representation of a compliant mechanism that is based on analytical expressions of geometric parameters. This analytical model agrees well with finite-element method calculations. We also examine a representative case experimentally and achieve accuracies better than 18%.
In this study, we present the high pressure spectroscopy of Y3Al2Ga3O12 (YAGG) and Y3Ga5O12 (YGG) ceramics doped with Ce(3+) and Cr(3+). We have found that high hydrostatic pressure recovers the ...Ce(3+) luminescence in YGG. The pressure-induced shifts of the ground state and the 5d1 excited state of Ce(3+) with respect to the conduction band edge were estimated. Our experimental data allowed us to also obtain the shifts of the conduction and valence band edges, and the ground state and the 5d1 state of Ce(3+) ions have been estimated with respect to the vacuum level. It has been shown that simple equivalence between the external hydrostatic pressure and intrinsic chemical pressure related to different compositions of the isostructural matrices does not exist in garnet lattices.
Characterizing the variability of the extragalactic sources used for calibration in the Atacama Large Millimeter/submillimeter Array (ALMA) is key to assess the flux scale uncertainty of science ...observations. To this end, we model the variability of 39 quasars which have been used by ALMA as secondary flux calibrators using continuous time stochastic processes. This formalism is specially adapted to the multi-frequency, quasi-periodic sampling which characterizes the calibration monitoring of ALMA. We find that simple mixtures of Ornstein-Uhlenbeck processes can describe well the flux and spectral index variability of these sources for Bands 3 and 7 (91.5 and 103.5, and 343.5 GHz, respectively). The spectral shape of the calibrators are characterized by negative spectral indices, mostly between −0.35 and −0.80, and with additional concavity. The model provides forecasts, interpolations, and uncertainty estimations for the observed fluxes that depend on the intrinsic variability of the source. These can be of practical use for the ALMA data calibrator survey and data quality assurance.
Abstract
We present 0.97 × 0.53 arcsec2 (470 pc × 250 pc) resolution CO (J = 2–1) observations towards the nearby luminous merging galaxy NGC 6240 with the Atacama Large Millimeter/submillimeter ...Array. We confirmed a strong CO concentration within the central 700 pc, which peaks between the double nuclei, surrounded by extended CO features along the optical dust lanes (∼11 kpc). We found that the CO emission around the central, a few kpc, has extremely broad velocity wings with full width at zero intensity ∼ 2000 km s−1, suggesting a possible signature of molecular outflow(s). In order to extract and visualize the high-velocity components in NGC 6240, we performed a multiple Gaussian fit to the CO data cube. The distribution of the broad CO components shows four extremely large line width regions (∼1000 km s−1) located 1–2 kpc away from both nuclei. Spatial coincidence of the large line width regions with H α, near-IR H2, and X-ray suggests that the broad CO (2–1) components are associated with nuclear outflows launched from the double nuclei.
![FIR-luminous [C ii] Emitter...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0004-637X/small "FIR-luminous [C ii] Emitters in the ALMA-SCUBA-2 COSMOS Survey (AS2COSMOS): The Nature of Submillimeter Galaxies in a 10 Comoving Megaparsec-scale Structure at z ∼ 4.6")
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