Why is observable radio recombination line emission from galactic HII regions always close to LTE

International Nuclear Information System (INIS)

Shaver, P.A.

1980-01-01

There is no evidence for significant deviations from LTE in single-dish observations of radio recombination line emission from galactic HII regions. This is in agreement with the known properties of HII regions, particularly their density variations and limited range of excitation parameters; the optimum configuration for strong observable non-LTE effects, low electron density and high emission measure, simply does not exist in galactic HII regions, and the observed lines are emitted under near-LTE conditions. Models of the Orion Nebulae and NGC 6604 are presented which fit all available data and show only weak stimulated emission. It is concluded that reliable electron temperatures can indeed be obtained from straightforward analysis of appropriate radio recombination lines. (orig.)

Young stellar population and star formation history ofW4 HII region/Cluster Complex

Science.gov (United States)

Panwar, Neelam

2018-04-01

The HII region/cluster complex has been a subject of numerous investigations to study the feedback effect of massive stars on their surroundings. Massive stars not only alter the morphology of the parental molecular clouds, but also influence star formation, circumstellar disks and the mass function of low-mass stars in their vicinity. However, most of the studies of low-mass stellar content of the HII regions are limited only to the nearby regions. We study the star formation in the W4 HII region using deep optical observations obtained with the archival data from Canada - France - Hawaii Telescope, Two-Micron All Sky Survey, Spitzer, Herschel and Chandra. We investigate the spatial distribution of young stellar objects in the region, their association with the remnant molecular clouds, and search for the clustering to establish the sites of recent star formation. Our analysis suggests that the influence of massive stars on circumstellar disks is significant only to thei! r immediate neighborhood. The spatial correlation of the young stars with the distribution of gas and dust of the complex indicate that the clusters would have formed in a large filamentary cloud. The observing facilities at the 3.6-m Devasthal Optical Telescope (DOT), providing high-resolution spectral and imaging capabilities, will fulfill the major objectives in the study of HII regions.

[NEII] Line Velocity Structure of Ultracompact HII Regions

Science.gov (United States)

Okamoto, Yoshiko K.; Kataza, Hirokazu; Yamashita, Takuya; Miyata, Takashi; Sako, Shigeyuki; Honda, Mitsuhiko; Onaka, Takashi; Fujiyoshi, Takuya

Newly formed massive stars are embedded in their natal molecular clouds and are observed as ultracompact HII regions. They emit strong ionic lines such as [NeII] 12.8 micron. Since Ne is ionized by UV photons of E>21.6eV which is higher than the ionization energy of hydrogen atoms the line probes the ionized gas near the ionizing stars. This enables to probe gas motion in the vicinity of recently-formed massive stars. High angular and spectral resolution observations of the [NeII] line will thus provide siginificant information on structures (e.g. disks and outflows) generated through massive star formation. We made [NeII] spectroscopy of ultracompact HII regions using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the 8.2m Subaru Telescope in July 2002. Spatial and spectral resolutions were 0.5"" and 10000 respectively. Among the targets G45.12+0.13 shows the largest spatial variation in velocity. The brightest area of G45.12+0.13 has the largest line width in the object. The total velocity deviation amounts to 50km/s (peak to peak value) in the observed area. We report the velocity structure of [NeII] emission of G45.12+0.13 and discuss the gas motion near the ionizing star.

Smoothed particle hydrodynamic simulations of expanding HII regions

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Bisbas, Thomas G.

2009-09-01

This thesis deals with numerical simulations of expanding ionized regions, known as HII regions. We implement a new three dimensional algorithm in Smoothed Particle Hydrodynamics for including the dynamical effects of the interaction between ionizing radiation and the interstellar medium. This interaction plays a crucial role in star formation at all epochs. We study the influence of ionizing radiation in spherically symmetric clouds. In particular, we study the spherically symmetric expansion of an HII region inside a uniform-density, non-self-gravitating cloud. We examine the ability of our algorithm to reproduce the known theoretical solution and we find that the agreement is very good. We also study the spherically symmetric expansion inside a uniform-density, self-gravitating cloud. We propose a new differential equation of motion for the expanding shell that includes the effects of gravity. Comparing its numerical solution with the simulations, we find that the equation predicts the position of the shell accurately. We also study the expansion of an off-centre HII region inside a uniform-density, non- self-gravitating cloud. This results in an evolution known as the rocket effect, where the ionizing radiation pushes and accelerates the cloud away from the exciting star leading to its dispersal. During this evolution, cometary knots appear as a result of Rayleigh-Taylor and Vishniac instabilities. The knots are composed of a dense head with a conic tail behind them, a structure that points towards the ionizing source. Our simulations show that these knots are very reminiscent of the observed structures in planetary nebula, such as in the Helix nebula. The last part of this thesis is dedicated to the study of cores ionized by an exciting source which is placed outside and far away from them. The evolution of these cores is known as radiation driven compression (or implosion). We perform simulations and compare our findings with results of other workers and we

New 20-cm radio-continuum study of the small Magellanic cloud - part III: Compact Hii regions

Directory of Open Access Journals (Sweden)

Wong G.F.

2012-01-01

Full Text Available We present and discuss a new catalogue of 48 compact Hii regions in the Small Magellanic Cloud (SMC and a newly created deep 1420 MHz (λ=20 cm radio-continuum image of the N19 region located in the southwestern part of the SMC. The new images were created by merging 1420 MHz radiocontinuum archival data from the Australian Telescope Compact Array. The majority of these detected radio compact Hii regions have rather flat spectral indices which indicates, as expected, that the dominant emission mechanism is of thermal nature.

Examining Sites of Recent Star Formation in the Galactic Center: A Closer Look at the Arched Filaments and H HII Regions

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Hankins, Matthew; Herter, Terry; Lau, Ryan; Morris, Mark; Mills, Elisabeth

2018-01-01

In this dissertation presentation, we analyze mid-infrared imaging of the Arched Filaments and H HII regions in the Galactic center taken with the Faint Object Infrared Camera for the SOFIA Telescope (FORCAST). Examining these regions are of great interest because they provide insights on star formation in the Galactic center and the interactions massive stars have with the ISM. The Arched Filaments are a collection of molecular cloud ridges which are ionized by the nearby Arches star cluster, and give the appearance of large (~25 pc) arch-like structures. The H HII regions are a collection of HII regions just to the west of the Arches cluster (~5-15 pc). The origin of the stars powering the H HII regions is uncertain, as they may have formed in a nearby molecular cloud or could be ejected members of the Arches cluster. FORCAST observations of these regions were used to study the morphology and heating structure of the HII regions, as well as constrain their luminosities.Color-temperature maps of the Arched Filaments created with the FORCAST data reveals fairly uniform dust temperatures (~70-100 K) across the length filaments. The temperature uniformity of the clouds can be explained if they are heated by the Arches cluster but are located at a larger distance from the cluster than they appear. The density of the Arched Filaments clouds was estimated from the FORCAST data and was found to be below the threshold for tidal shearing, indicating that that the clouds will be destroyed by the strong tidal field near the Galactic center. To the west of the Arched Filaments, there is an interesting collection of HII regions, referred to as the H HII regions. These regions are likely heated by massive O/B type stars, and the morphology of the dust emission associated with these objects indicate a mixture of potential in situ formation mechanisms and interlopers. Interestingly, FORCAST imaging of the H HII regions also reveal several compact sources, which may be young

CO J=2-1 observations toward southern HII regions

International Nuclear Information System (INIS)

Martin, R.N.; Ruf, K.; Wilson, T.L.; Zimmermann, P.; Emerson, D.T.

1983-01-01

A spectral line receiver system developed at the Max-Planck-Institut fuer Radioastronomie in Bonn was installed on the ESO 3.6-m and 1-m telescopes in July 1981. The cooled mixer front end gave DSB receiver temperatures of 260-600 K at 230 GHz. The spectrometer was a 256 x 1 MHz filterbank. The authors have observed the CO 2-1 transition towards 42 positions corresponding to the brightest southern HII regions. (Auth.)

The relation between radio flux density and ionizing ultra-violet flux for HII regions and supernova remnants in the Large Magellanic cloud

Directory of Open Access Journals (Sweden)

Filipović M.D.

2003-01-01

Full Text Available We present a comparison between the Parkes radio surveys (Filipović et al 1995 and Vacuum Ultra-Violet (VUV surveys (Smith et al. 1987 of the Large Magellanic Clouds (LMC. We have found 72 sources in common in the LMC which are known HII regions (52 and supernova remnants (SNRs (19. Some of these radio sources are associated with two or more UV stellar associations. A comparison of the radio flux densities and ionizing UV flux for HII regions shows a very good correlation, as expected from theory. Many of the Magellanic Clouds (MCs SNRs are embedded in HII regions, so there is also a relation between radio and UV which we attribute to the surrounding HII regions.

Rotational Modulation and Activity Cycles at Rotational Extremes: 25 yrs of NURO Photometry for HII 1883

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Milingo, Jackie; Saar, Steven; Marschall, Laurence

2018-01-01

We present a 25 yr compilation of V-band differential photometry for the Pleiades K dwarf HII 1883 (V660 Tau). HII 1883 has a rotational period of ~ 0.24 d and displays significant rotational modulation due to non-uniform surface brightness or "starspots". Preliminary work yields a cycle period of ~ 9 yrs and rotational shear (ΔP_rot/) considerably less than solar. HII 1883 is one of the fastest rotating single stars with a known cycle. With additional data available we compare newly determined P_cyc and ΔP_rot/ values with those of other stars, putting HII 1883 into the broader context of dynamo properties in single cool dwarfs.

HII regions in collapsing massive molecular clouds

International Nuclear Information System (INIS)

Yorke, H.W.; Bodenheimer, P.; Tenorio-Tagle, G.

1982-01-01

Results of two-dimensional numerical calculations of the evolution of HII regions associated with self-gravitating, massive molecular clouds are presented. Depending on the location of the exciting star, a champagne flow can occur concurrently with the central collapse of a nonrotating cloud. Partial evaporation of the cloud at a rate of about 0.005 solar masses/yr results. When 100 O-stars are placed at the center of a freely falling cloud of 3x10 5 solar masses no evaporation takes place. Rotating clouds collapse to disks and the champagne flow can evaporate the cloud at a higher rate (0.01 solar masses/yr). It is concluded that massive clouds containing OB-stars have lifetimes of no more than 10 7 yr. (Auth.)

Low surface brightness spiral galaxies

International Nuclear Information System (INIS)

Romanishin, W.

1980-01-01

This dissertation presents an observational overview of a sample of low surface brightness (LSB) spiral galaxies. The sample galaxies were chosen to have low surface brightness disks and indications of spiral structure visible on the Palomar Sky Survey. They are of sufficient angular size (diameter > 2.5 arcmin), to allow detailed surface photometry using Mayall 4-m prime focus plates. The major findings of this dissertation are: (1) The average disk central surface brightness of the LSB galaxies is 22.88 magnitude/arcsec 2 in the B passband. (2) From broadband color measurements of the old stellar population, we infer a low average stellar metallicity, on the order of 1/5 solar. (3) The spectra and optical colors of the HII regions in the LSB galaxies indicate a lack of hot ionizing stars compared to HII regions in other late-type galaxies. (4) The average surface mass density, measured within the radius containing half the total mass, is less than half that of a sample of normal late-type spirals. (5) The average LSB galaxy neutral hydrogen mass to blue luminosity ratio is about 0.6, significantly higher than in a sample of normal late-type galaxies. (6) We find no conclusive evidence of an abnormal mass-to-light ratio in the LSB galaxies. (7) Some of the LSB galaxies exhibit well-developed density wave patterns. (8) A very crude calculation shows the lower metallicity of the LSB galaxies compared with normal late-type spirals might be explained simply by the deficiency of massive stars in the LSB galaxies

Properties of the HII Regions Derived Using Integral Field Spectroscopy

Czech Academy of Sciences Publication Activity Database

Sánchez, Sebastián F.

2013-01-01

Roč. 2013, č. 1 (2013), 596501/1-596501/14 ISSN 1687-7969 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100031241; Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100031201 Program:M Institutional support: RVO:67985815 Keywords : H-II regions * star -foraming galaxies * chemo-spectrophotometric evolution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 1.234, year: 2013

Observations of Anomalous Microwave Emission from HII Regions

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Clive Dickinson

2013-01-01

free-free emission from UCHII regions may be also be significant in some cases. The AME emissivity, defined as the ratio of the AME brightness to the 100 μm brightness, is comparable to the value observed in high-latitude diffuse cirrus in some regions, but is significantly lower in others. However, this value is dependent on the dust temperature. More data, both at high frequencies (>~5 GHz and high resolution (~1′ or better is required to disentangle the emission processes in such complex regions.

Exploring the 13CO/C18O abundance ratio towards Galactic young stellar objects and HII regions

Science.gov (United States)

Areal, M. B.; Paron, S.; Celis Peña, M.; Ortega, M. E.

2018-05-01

Aims: Determining molecular abundance ratios is important not only for the study of Galactic chemistry, but also because they are useful to estimate physical parameters in a large variety of interstellar medium environments. One of the most important molecules for tracing the molecular gas in the interstellar medium is CO, and the 13CO/C18O abundance ratio is usually used to estimate molecular masses and densities of regions with moderate to high densities. Nowadays isotope ratios are in general indirectly derived from elemental abundances ratios. We present the first 13CO/C18O abundance ratio study performed from CO isotope observations towards a large sample of Galactic sources of different natures at different locations. Methods: To study the 13CO/C18O abundance ratio, we used 12CO J = 3 - 2 data obtained from the CO High-Resolution Survey, 13CO and C18O J = 3 - 2 data from the 13CO/C18O (J = 3 - 2) Heterodyne Inner Milky Way Plane Survey, and some complementary data extracted from the James Clerk Maxwell Telescope database. We analyzed a sample of 198 sources composed of young stellar objects (YSOs), and HII and diffuse HII regions as catalogued in the Red MSX Source Survey in 27.°5 ≤ l ≤ 46.°5 and |b|0.°5. Results: Most of the analyzed sources are located in the galactocentric distance range 4.0-6.5 kpc. We found that YSOs have, on average, lower 13CO/C18O abundance ratios than HII and diffuse HII regions. Taking into account that the gas associated with YSOs should be less affected by the radiation than in the case of the others sources, selective far-UV photodissociation of C18O is confirmed. The 13CO/C18O abundance ratios obtained in this work are systematically lower than those predicted from the known elemental abundance relations. These results will be useful in future studies of molecular gas related to YSOs and HII regions based on the observation of these isotopes.

H-alpha observations of Sh2-190, Sh2-222, Sh2-229, Sh2-236 HII regions

Science.gov (United States)

Sahan, Muhittin

2018-02-01

Hα spectral line (6563Å) profiles of four northern HII regions in the our galaxy (Sh2-190, Sh2-222, Sh2-229, Sh2-236) have been obtained using DEFPOS spectrometer, located at coude focus of 150 cm RTT150 telescope at TUBITAK National Observatory (TUG, Antalya, Turkey). Observations were carried out at nights of 2015 December 24-27 with long exposure times ranging from 900s to 3600s. The LSR velocities and the linewidths (Full Width Half Maximum: FWHM) of the Hα emission lines were found to be in the range of -45.46 kms-1 to +3.57 kms-1 and 38.50 kms-1 to 44.10 kms-1, respectively. The Sh2-229 HII region is the faintest one (211.16 R), while the Sh2-236 HII region (IC410) is brightest source (535.75 R). The LSR velocity and the line width (FWHM) results of the DEFPOS/RTT150 system were compared with the data by several authors given in literature and results of DEFPOS data were found to be in good agreement with data given in literature.

VizieR Online Data Catalog: Inner/outer HII regions: galaxy sample (Rodriguez-Baras+, 2018)

Science.gov (United States)

Rodriguez-Baras, M.; Diaz, A. I.; Rosales-Ortega, F. F.; Sanchez, S. F.

2017-11-01

Physical properties for 263 isolated spiral galaxies, observed by the CALIFA survey, are presented. These galaxies compose this work galaxy sample. For each galaxy redshift, morphological type, inclination, distance, effective radius, g and r SDSS magnitudes, absolute B magnitude and total number of HII regions extracted in the galaxy are given. (1 data file).

VizieR Online Data Catalog: Multiwavelength study of HII region S311 (Yadav+, 2016)

Science.gov (United States)

Yadav, R. K.; Pandey, A. K.; Sharma, S.; Ojha, D. K.; Samal, M. R.; Mallick, K. K.; Jose, J.; Ogura, K.; Richichi, A.; Irawati, P.; Kobayashi, N.; Eswaraiah, C.

2017-11-01

We observed the HII region S311 (centred on RA(2000)=07:52:24, DE(2000)=-26:24:58.40) in NIR broad-bands J (1.25um), H (1.63um) and Ks (2.14um) on 2010 March 3 using the Infrared Side Port Imager (ISPI) camera mounted on the CTIO Blanco 4-m telescope. We consider only those sources having error data files).

HII regions in IC 1613: The ISM in a nearby dwarf irregular galaxy

Science.gov (United States)

Price, Jill S.; Mason, Stephen F.; Gullixson, Craig A.

1990-01-01

IC 1613, a nearby (725 kpc distant) dwarf irregular galaxy, has always been known to contain large, ring-shaped HII regions in its northeast corner. A new H alpha image has been obtained using the Bell Labs Charge Coupled Device (CCD) camera, an RCA 320 X 512 pixel-thinned, back-illuminated CCD, an H alpha filter of central wavelength 6562 A and width (full width half maximum) of 30 A, and the 42 inch telescope at Lowell Observatory. The low resolution images exhibit many new, faint features.

El medio interestelar en los alrededores de la region HII Sh2-183

Science.gov (United States)

Cichowolski, S.; Cappa, C. E.; Blanco, A.; Eppens, L.; Ertini, K.; Leiva, M. M.

2017-10-01

We present a multiwavelength study of the HII region Sh2-183, located at (,) = (123.3,+3.0) at a distance of 7.0 1.5 kpc from the Sun. Based on the radio continuum data we estimated the amount of ionized gas, the electronic density, and the number of ionizing photons needed to keep the region ionized, which is important since the star/s responsible of the region was/were not detected yet. On the other hand, based on IRAS data we have analyzed the dust temperature and distribution. The Hi line data allowed the detection of a shell-like structure surrounding the ionized gas and the CO data revealed the presence of 6 molecular clouds probably related to Sh2-183, which harbor several young stellar object candidates.

Kinematic Study of Ionized and Molecular Gases in Ultracompact HII Region in Monoceros R2

Science.gov (United States)

Kim, Hwihyun; Lacy, John H.; Jaffe, Daniel Thomas

2017-06-01

Monoceros R2 (Mon R2) is an UltraCompact HII region (UCHII) surrounded by several PhotoDissociation Regions (PDRs). It is an excellent example to investigate the chemistry and physics of early stage of massive star formation due to its proximity (830pc) and brightness. Previous studies suggest that the wind from the star holds the ionized gas up against the dense molecular core and the higher pressure at the head drives the ionized gas along the shell. In order for the model to work, there should be evidence for dense molecular gas along the shell walls, irradiated by the UCHII region and perhaps entrained into the flow along the walls.We obtained the Immersion Grating INfrared Spectrograph (IGRINS) spectra of Mon R2 to study the kinematic patterns in the areas where ionized and molecular gases interact. The position-velocity maps from the high resolution (R~45,000) H- and K-band (1.4-2.5μm) IGRINS spectra demonstrate that the ionized gases (Brackett and Pfund series, He and Fe emission lines; Δv ≈ 40km/s) flow along the walls of the surrounding clouds. This is consistent with the model by Zhu et al. (2008). In the PV maps of the H2 emission lines there is no obvious motion (Δv ≈ 10km/s) of the molecular hydrogen right at the ionization boundary. This implies that the molecular gas is not taking part in the flow as the ionized gas is moving along the cavity walls.This work used the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation (NSF; grant AST-1229522), of the University of Texas at Austin, and of the Korean GMTProject of KASI.

Star bursts and giant HII regions

International Nuclear Information System (INIS)

Pagel, B.E.J.

1990-01-01

Massive star formation bursts occur in a variety of galactic environments and can temporarily dominate the light output of a galaxy even when a relatively small proportion of its mass is involved. Inferences about their ages, the IMF and its dependence on chemical composition are still somewhat wobbly owing to an excess of unknowns, but certain things can be deduced from emission spectra of associated H II regions when due regard is paid to the effects of chemical composition and ionization parameter: In particular, largest ionization parameters and effective temperatures of exciting stars, at any given oxygen abundance, are anti-correlated with the abundance, and the second effect suggests an increasing proportion of more massive stars at lower abundances, although this is not yet satisfactorily quantified. A new blue compact galaxies could be very young, but it is equally possible that there is an older population of low surface brightness. Some giant H II regions may be self-polluted with nitrogen and helium due to winds from massive stars in the associated burst. (orig.)

Formation of Pillars at the Boundaries between HII Regions and Molecular Clouds

International Nuclear Information System (INIS)

Mizuta, A; Kane, J O; Pound, M W; Remington, B A; Ryutov, D D; Takabe, H

2006-01-01

We investigate numerically the hydrodynamic instability of an ionization front (IF) accelerating into a molecular cloud, with imposed initial perturbations of different amplitudes. When the initial amplitude is small, the imposed perturbation is completely stabilized and does not grow. When the initial perturbation amplitude is large enough, roughly the ratio of the initial amplitude to wavelength is greater than 0.02, portions of the IF temporarily separate from the molecular cloud surface, locally decreasing the ablation pressure. This causes the appearance of a large, warm HI region and triggers nonlinear dynamics of the IF. The local difference of the ablation pressure and acceleration enhances the appearance and growth of a multimode perturbation. The stabilization usually seen at the IF in the linear regimes does not work due to the mismatch of the modes of the perturbations at the cloud surface and in density in HII region above the cloud surface. Molecular pillars are observed in the late stages of the large amplitude perturbation case. The velocity gradient in the pillars is in reasonably good agreement with that observed in the Eagle Nebula. The initial perturbation is imposed in three different ways: in density, in incident photon number flux, and in the surface shape. All cases show both stabilization for a small initial perturbation and large growth of the second harmonic by increasing amplitude of the initial perturbation above a critical value

On the relation of Hsub(α) plage brightness variations in solar active regions

International Nuclear Information System (INIS)

Ogir', M.B.

1980-01-01

The variations of hydrogen plage brightnesses in seven spot groups belonging to five active regions are discussed. The observations were made on the Crimean observatory coronograph in 1974 and 1977. The correlation in brightness variations of plages situated in the regions of growing magnetic field was obtained. This was observed in the plages on one spot group as well as in the different groups removing on about 27x10 4 km. In developed groups correlations are mainly seen within a spot group and they are expressed better during flares. The correlations of brightnesses are changing during the active region evolution. Three days observations showed good brightness correlations of all plages in the growing magnetic field region and their decrease that can be explained by the field weakening during natural active region evolution or by the strong flare influence. The existence of the simultaneous variations of brightness in the regions with the growing magnetic field speaks in favour of the simultaneous carring-out of magnetic field or its disturbances into the chromosphere [ru

Triggered massive star formation associated with the bubble Hii region Sh2-39 (N5)

Science.gov (United States)

Duronea, N. U.; Cappa, C. E.; Bronfman, L.; Borissova, J.; Gromadzki, M.; Kuhn, M. A.

2017-09-01

Aims: We perform a multiwavelength analysis of the bubble Hii region Sh2-39 (N5) and its environs with the aim of studying the physical properties of Galactic IR bubbles and exploring their impact in triggering massive star formation. Methods: To analyze the molecular gas, we used CO(3-2) and HCO+(4-3) line data obtained with the on-the-fly technique from the ASTE telescope. To study the distribution and physical characteristics of the dust, we made use of archival data from ATLASGAL, Herschel, and MSX, while the ionized gas was studied making use of an NVSS image. We used public WISE, Spitzer, and MSX point source catalogs to search for infrared candidate young stellar objects (YSOs) in the region. To investigate the stellar cluster [BDS2003]6 we used IR spectroscopic data obtained with the ARCoIRIS spectrograph, mounted on Blanco 4 m Telescope at CTIO, and new available IR Ks band observations from the VVVeXtended ESO Public Survey (VVVX). Results: The new ASTE observations allowed the molecular gas component in the velocity range from 30 km s-1 to 46 km s-1, associated with Sh2-39, to be studied in detail. The morphology of the molecular gas suggests that the ionized gas is expanding against its parental cloud. We identified four molecular clumps, which were likely formed by the expansion of the ionization front, and determined some of their physical and dynamical properties. Clumps with HCO+ and 870 μm counterparts show evidence of gravitational collapse. We identified several candidate YSOs across the molecular component. Their spatial distribution and the fragmentation time derived for the collected layers of the molecular gas suggest that massive star formation might have been triggered by the expansion of the nebula via the collect and collapse mechanism. The spectroscopical distance obtained for the stellar cluster [BDS2003]6, placed over one of the collapsing clumps in the border of the Hii region, reveals that this cluster is physically associated with

Starbursts and the chemical evolution of HII galaxies: ages of bursts VS local environmental pollution

International Nuclear Information System (INIS)

Pagel, B.E.J.

1987-01-01

Results previously published for oxygen, nitrogen and helium abundances in HII galaxies are revised to allow for collisional contributions to the helium lines and a few further objects added. The relationships found are similar in general to those found previously, though with fewer objects departing from the dY/dZ relation derived by Peimbert and his colleagues, and are confirmed by a principal component analysis which shows that O/H accounts for about half of the variation in helium but N/H for essentially all of it. These effects are consistent with an additional component of helium and secondary nitrogen, superposed on primary nitrogen, with the additional component either coming from low-mass stars made in very old bursts or resulting from local pollution of the observed HII regions by winds from massive stars within them. Evidence from different regions of POX 4 and NGC 5253 gives some slight support to the latter hypothesis

On the anomaly of the far UV extinction law in the 30 Doradus region

International Nuclear Information System (INIS)

Koornneef, J.

1976-01-01

Area-integrated ultraviolet observations made with the Netherlands Astronomical Satellite (ANS), of about 800 fields in a 0.7 square degree region around the giant HII region 30 Doradus in the Large Magellanic Cloud are discussed. The five-channel ANS photometric system is shown to be information redundant in the present application; the observations can therefore be discussed in terms of only two parameters: visual brightness and a temperature parameter (colour). A colour-brightness diagram is presented for about 600 fields with good quality measurements with the conclusion that most of the spread in colour is caused by differential extinction. By various independent methods it was found that the 2200 A-feature is deficient by a factor of three on a logarithmic scale relative to the average galactic extinction law

Condições físicas em galáxias HII

Science.gov (United States)

Kehrig, C.; Telles, E.; Cuisinier, F.

2003-08-01

Galáxias HII são galáxias anãs de baixa luminosidade que apresentam alta taxa de formação estelar. Seus espectros são dominados por intensas linhas de emissão devido à fotoionização pela presença de um grande número de estrelas do tipo O e B. Nós apresentamos um catálogo espectrofotométrico de 111 galáxias HII observadas no telescópio 1.52m do ESO com o espectrógrafo Boller & Chivens. Determinamos propriedades estatísticas da amostra e derivamos condições físicas (temperatura eletrônica, densidade eletrônica) e abundâncias químicas. Para algumas galáxias, fomos também capazes de resolver espacialmente regiões de formação estelar individuais e determinar propriedades espectroscópicas para estas regiões separadamente, o que nos permitiu avaliar as flutuações das condições físico-químicas dentro das galáxias HII. Em particular, vimos que apesar das galáxias HII apresentarem formação estelar espalhada ao longo do corpo da galáxia, são objetos quimicamente homogêneos. A fim de estudar a evolução temporal dos objetos durante o tempo de vida das estrelas ionizantes construimos também alguns diagramas relacionando razões de linhas de emissão com a largura equivalente de Hb (EW(Hb)). Para interpretar tais diagramas utilizamos modelos de fotoionização para populações estelares integradas. Concluímos que as galáxias HII não correspondem a simples idéia de um burst instantâneo envolvido por um gás opaco aos fótons ionizantes e com densidade constante. As relações observadas entre razões de linhas e EW(Hb) podem ser melhor compreendidas se as galáxias HII apresentarem populações estelares mais velhas, que contribuem para o contínuo óptico observado.

SOLAR CYCLE VARIATIONS OF THE RADIO BRIGHTNESS OF THE SOLAR POLAR REGIONS AS OBSERVED BY THE NOBEYAMA RADIOHELIOGRAPH

Energy Technology Data Exchange (ETDEWEB)

Nitta, Nariaki V.; DeRosa, Marc L. [Lockheed Martin Advanced Technology Center, Dept/A021S, B/252, 3251 Hanover Street, Palo Alto, CA 94304 (United States); Sun, Xudong; Hoeksema, J. Todd [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

2014-01-10

We have analyzed daily microwave images of the Sun at 17 GHz obtained with the Nobeyama Radioheliograph (NoRH) in order to study the solar cycle variations of the enhanced brightness in the polar regions. Unlike in previous works, the averaged brightness of the polar regions is obtained from individual images rather than from synoptic maps. We confirm that the brightness is anti-correlated with the solar cycle and that it has generally declined since solar cycle 22. Including images up to 2013 October, we find that the 17 GHz brightness temperature of the south polar region has decreased noticeably since 2012. This coincides with a significant decrease in the average magnetic field strength around the south pole, signaling the arrival of solar maximum conditions in the southern hemisphere more than a year after the northern hemisphere. We do not attribute the enhanced brightness of the polar regions at 17 GHz to the bright compact sources that occasionally appear in synthesized NoRH images. This is because they have no correspondence with small-scale bright regions in images from the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory with a broad temperature coverage. Higher-quality radio images are needed to understand the relationship between microwave brightness and magnetic field strength in the polar regions.

Star formation in the inner galaxy: a far-infrared and radio study of two H2 regions

International Nuclear Information System (INIS)

Lester, D.F.; Dinerstein, H.L.; Werner, M.W.; Harvey, P.M.; Evans, N.J.; Brown, R.L.

1985-09-01

Far-infrared and radio continuum maps have been made of the central 6' of the inner-galaxy HII regions G30.8-0.0 (in the W43 complex) and G25.4-0.2, along with radio and molecular line measurements at selected positions. The purpose of this study is an effort to understand star formation in the molecular ring at 5 kpc in galactic radius. Measurements at several far infrared wavelengths allow the dust temperature structures and total far infrared fluxes to be determined. Comparison of the radio and infrared maps shows a close relationship between the ionized gas and the infrared-emitting material. There is evidence that parts of G30.8 are substantially affected by extinction, even at far-infrared wavelengths. Using radio recombination line and CO line data for G25.4-0.2, the distance ambiguity for this source is resolved. The large distance previously ascribed to the entire complex is found to apply to only one of the two main components. The confusion in distance determination is found to result from an extraordinary near-superposition of two bright HII regions. Using the revised distances of 4.3 kpc for G25.4SE and 12 kpc for G25.4NW, it is found that the latter, which is apparently the fainter of the two sources, is actually the more luminous. The ratio of total luminosity to ionizing luminosity is very similar to that of HII regions in the solar circle. Assuming a coeval population of ionizing stars, a normal initial mass function is indicated

Estudo da região HII galática NGC 2579

Science.gov (United States)

Riffel, R.; Copetti, M. V. F.

2003-08-01

Desde a descoberta dos gradientes de abundância química em galáxias espirais, as regiões HII galáticas têm sido intensamente estudadas com o objetivo de determinar a forma do gradiente de abundância química na Via-Láctea. Entretanto, a forma do gradiente galático continua controversa e existem muitas regiões HII que continuam inexploradas. A região HII galática NGC 2579 é um objeto que aparece em imagens Ha, como uma pequena mancha brilhante de aproximadamente 2 segundos de arco de diâmetro a 20 segundos de arco ao leste de RCW 20, sendo NGC 2579 muitas vezes confundida com esta última. Apesar de seu alto brilho superficial, NGC 2579 é um objeto pouco estudado provavelmente por problemas de identificação deste objeto. Como parte de um projeto de reavaliação dos gradientes de abundância química das regiões HII na Via-Láctea, estamos realizando um estudo extensivo das propriedades físicas básicas como temperatura eletrônica, densidade eletrônica e composição química da região HII galática NGC 2579. Analisamos dados espectrofotométricos de fenda longa na faixa de 3700Å a 7750Å obtidos com o telescópio de 1.52 m do ESO, Chile, em 2002. Determinamos a temperatura eletrônica usando a razão entre as linhas do [OIII] (l4959+l5007/l4363) e a densidade eletrônica pela razão entre as linhas do [SII] (l6716/l6731). As abundâncias químicas do O, N, Cl, S, Ne e He foram determinadas. Realizamos um estudo de imagens fotométricas nas bandas UBVRI obtidas em 2000 no observatório astronômico San Pedro Mártir, México, para identificar e classificar as estrelas ionizantes de NGC 2579 e determinar a distância deste objeto.

Water masers in NGC7538 region

Science.gov (United States)

Kameya, Osamu

We observed H2O masers towards NGC7538 molecular-cloud core using VERA (VLBI Experiment of Radio Astrometry). This region is in the Perseus arm at a distance of about 2.7 kpc and is famous for its multiple, massive star formation. There are three areas there, N(IRS1-3), E(IRS9), and S(IRS11), each having a strong IR source(s), ultra-compact HII region(s), bipolar outflow, high-density core, and OH/H2O/CH3OH masers. We made differential VLBI observations towards the NGC7538 H2O maser sources at N and S and a reference source, Cepheus A H2O maser, simultaneously. The Cepheus A region is separated by 2 degrees from the NGC7538 region. The positions of H2O masers in N and S regions, distributed around the ultra-compact HII regions, are basically consistent with those found by means of interferometric observations of past 29 years. The masers may come from interface regions between the ultra-compact HII regions and the environments of dense molecular gas.

Probing the Galactic Structure of the Milky Way with H II Regions

Science.gov (United States)

Red, Wesley Alexander; Wenger, Trey V.; Balser, Dana; Anderson, Loren; Bania, Thomas

2018-01-01

Mapping the structure of the Milky Way is challenging since we reside within the Galactic disk and distances are difficult to determine. Elemental abundances provide important constraints on theories of the formation and evolution of the Milky Way. HII regions are the brightest objects in the Galaxy at radio wavelengths and are detected across the entire Galactic disk. We use the Jansky Very Large Array (VLA) to observe the radio recombination line (RRL) and continuum emission of 120 Galactic HII regions located across the Galactic disk. In thermal equilibrium, metal abundances are expected to set the nebular electron temperature with high abundances producing low temperatures. We derive the metallicity of HII regions using an empirical relation between an HII region's radio recombination line-to-continuum ratio and nebular metallicity. Here we focus on a subset of 20 HII regions from our sample that have been well studied with the Green Bank Telescope (GBT) to test our data reduction pipeline and analysis methods. Our goal is to expand this study to the Southern skies with the Australia Telescope Compact Array and create a metallicity map of the entire Galactic disk.

The NGC 7538 region: the distribution and dynamics of molecules compared with those of HI and H+

International Nuclear Information System (INIS)

Dickel, H.R.; Dickel, J.R.; Wilson, W.J.

1982-01-01

CO maps and preliminary H 2 S and H 2 CO data for the molecular cloud associated with the HII region NGC 7538 are compared with the distributions of ionized and neutral hydrogen. South of the optical HII region is a ridge of high 13 CO column density with cold, self-absorbed HI gas just beyond it. A dense clump within the ridge is found adjacent to the HII region in the southeast. The percentage of the hydrogen in atomic form varies from approximately 0.1% in the dense region to approximately 0.8% in the outskirts. The lower-density region of expanding gas seen next to the HII region in the southwest is attributed to the passage of a molecular dissociation wave. (Auth.)

A Velocity Structure Analysis of Giant Molecular Cloud Associated with HII Region S152

Directory of Open Access Journals (Sweden)

Woo-Yeol Choi

2005-06-01

Full Text Available S152 is a small bright emission nebula located in the Perseus arm. Its optical diameter corresponds to 1.5 pc for an adopted distance 3.5 kpc. However, S152 is a part of a giant molecular cloud complex, which consists of several dense cores, containing active star-forming sites, and well aligned arm-like features. We analyzed the FCRAO 12CO (J = 1→0 Outer Galaxy Survey data in this region to study the kinematical structure of this region, which resembles a big ``scorpion". We found that there exist three different velocity components, about --54.5, --50.4, --48.8 km s-1, depending on the position of the ``scorpion". There also exist velocity gradients of 0.21 km s-1 pc-1 and 0.16 km s-1 pc-1 through the whole extent of the ``scorpion". Interestingly, these two velocity gradients show an opposite direction with each other. It is likely that the velocity structure of this region may result from the mergence of different gas clouds, and the interaction with the SNR 109.1-1.0 occurred later, mostly at the region around the ``head of the scorpion" only.

Lactobacillus paracasei HII01, xylooligosaccharides, and synbiotics reduce gut disturbance in obese rats.

Science.gov (United States)

Thiennimitr, Parameth; Yasom, Sakawdaurn; Tunapong, Wannipa; Chunchai, Titikorn; Wanchai, Keerati; Pongchaidecha, Anchalee; Lungkaphin, Anusorn; Sirilun, Sasithorn; Chaiyasut, Chaiyavat; Chattipakorn, Nipon; Chattipakorn, Siriporn C

2018-03-20

The beneficial effects of pro-, pre-, and synbiotics on obesity with insulin resistance have been reported previously. However, the strain-specific effect of probiotics and the combination with various types of prebiotic fiber yield controversial outcomes and limit clinical applications. Our previous study demonstrated that the probiotic Lactobacillus paracasei (L. paracasei) HII01, prebiotic xylooligosaccharide (XOS), and synbiotics share similar efficacy in attenuating cardiac mitochondrial dysfunction in obese-insulin resistant rats. Nonetheless, the roles of HII01 and XOS on gut dysbiosis and gut inflammation under obese-insulin resistant conditions have not yet, to our knowledge, been investigated. Our hypothesis was that pro-, pre-, and synbiotics improve the metabolic parameters in obese-insulin resistant rats by reducing gut dysbiosis and gut inflammation. Male Wistar rats were fed with either a normal or high-fat diet that contained 19.77% and 59.28% energy from fat, respectively, for 12 wk. Then, the high-fat diet rats were fed daily with a 10 8 colony forming unit of the probiotic HII01, 10% prebiotic XOS, and synbiotics for 12 wk. The metabolic parameters, serum lipopolysaccharide levels, fecal Firmicutes/Bacteroidetes ratios, levels of Enterobacteriaceae, Bifidobacteria, and gut proinflammatory cytokine gene expression were quantified. The consumption of probiotic L. paracasei HII01, prebiotic XOS, and synbiotics for 12 wk led to a decrease in metabolic endotoxemia, gut dysbiosis (a reduction in the Firmicutes/Bacteroidetes ratio and Enterobacteriaceae), and gut inflammation in obese-insulin resistant rats. Pro-, pre-, and synbiotics reduced gut dysbiosis and gut inflammation, which lead to improvements in metabolic dysfunction in obese-insulin resistant rats. Copyright © 2018 Elsevier Inc. All rights reserved.

The GAN Exonuclease or the Flap Endonuclease Fen1 and RNase HII Are Necessary for Viability of Thermococcus kodakarensis.

Science.gov (United States)

Burkhart, Brett W; Cubonova, Lubomira; Heider, Margaret R; Kelman, Zvi; Reeve, John N; Santangelo, Thomas J

2017-07-01

Many aspects of and factors required for DNA replication are conserved across all three domains of life, but there are some significant differences surrounding lagging-strand synthesis. In Archaea , a 5'-to-3' exonuclease, related to both bacterial RecJ and eukaryotic Cdc45, that associates with the replisome specifically through interactions with GINS was identified and designated GAN (for G INS- a ssociated n uclease). Despite the presence of a well-characterized flap endonuclease (Fen1), it was hypothesized that GAN might participate in primer removal during Okazaki fragment maturation, and as a Cdc45 homologue, GAN might also be a structural component of an archaeal CMG (Cdc45, MCM, and GINS) replication complex. We demonstrate here that, individually, either Fen1 or GAN can be deleted, with no discernible effects on viability and growth. However, deletion of both Fen1 and GAN was not possible, consistent with both enzymes catalyzing the same step in primer removal from Okazaki fragments in vivo RNase HII has also been proposed to participate in primer processing during Okazaki fragment maturation. Strains with both Fen1 and RNase HII deleted grew well. GAN activity is therefore sufficient for viability in the absence of both RNase HII and Fen1, but it was not possible to construct a strain with both RNase HII and GAN deleted. Fen1 alone is therefore insufficient for viability in the absence of both RNase HII and GAN. The ability to delete GAN demonstrates that GAN is not required for the activation or stability of the archaeal MCM replicative helicase. IMPORTANCE The mechanisms used to remove primer sequences from Okazaki fragments during lagging-strand DNA replication differ in the biological domains. Bacteria use the exonuclease activity of DNA polymerase I, whereas eukaryotes and archaea encode a flap endonuclease (Fen1) that cleaves displaced primer sequences. RNase HII and the GINS-associated exonuclease GAN have also been hypothesized to assist in primer

Vibration test of 1/5 scale H-II launch vehicle

Science.gov (United States)

Morino, Yoshiki; Komatsu, Keiji; Sano, Masaaki; Minegishi, Masakatsu; Morita, Toshiyuki; Kohsetsu, Y.

In order to predict dynamic loads on the newly designed Japanese H-II launch vehicle, the adequacy of prediction methods has been assessed by the dynamic scale model testing. The three-dimensional dynamic model was used in the analysis to express coupling effects among axial, lateral (pitch and yaw) and torsional vibrations. The liquid/tank interaction was considered by use of a boundary element method. The 1/5 scale model of the H-II launch vehicle was designed to simulate stiffness and mass properties of important structural parts, such as core/SRB junctions, first and second stage Lox tanks and engine mount structures. Modal excitation of the test vehicle was accomplished with 100-1000 N shakers which produced random or sinusoidal vibrational forces. The vibrational response of the test vehicle was measured at various locations with accelerometers and pressure sensor. In the lower frequency range, corresmpondence between analysis and experiment was generally good. The basic procedures in analysis seem to be adequate so far, but some improvements in mathematical modeling are suggested by comparison of test and analysis.

Balloon observations of galactic and extragalactic objects at 100 microns.

Science.gov (United States)

Hoffmann, W. F.

1972-01-01

Recent far-infrared balloon-borne instruments have yielded observations of a number of bright sources at 100 microns. Many of these coincide with HII regions where molecular line emision has been detected. There is some indication of 100 micron emission which does not coincide with radio measurements.

A bright-rimmed cloud sculpted by the H ii region Sh2-48

Science.gov (United States)

Ortega, M. E.; Paron, S.; Giacani, E.; Rubio, M.; Dubner, G.

2013-08-01

Aims: We characterize a bright-rimmed cloud embedded in the H ii region Sh2-48 while searching for evidence of triggered star formation. Methods: We carried out observations towards a region of 2' × 2' centered at RA = 18h22m11.39s, Dec = -14°35'24.81''(J2000) using the Atacama Submillimeter Telescope Experiment (ASTE; Chile) in the 12CO J = 3-2, 13CO J = 3-2, HCO+J = 4-3, and CS J = 7-6 lines with an angular resolution of about 22''. We also present radio continuum observations at 5 GHz carried out with the Jansky Very Large Array (JVLA; EEUU) interferometer with a synthetized beam of 7'' × 5''. The molecular transitions were used to study the distribution and kinematics of the molecular gas of the bright-rimmed cloud. The radio continuum data was used to characterize the ionized gas located on the illuminated border of this molecular condensation. Combining these observations with infrared public data allowed us to build up a comprehensive picture of the current state of star formation within this cloud. Results: The analysis of our molecular observations reveals a relatively dense clump with n(H2) ~ 3 × 103cm-3, located in projection onto the interior of the H ii region Sh2-48. The emission distribution of the four observed molecular transitions has, at VLSR ~ 38 km s-1, morphological anticorrelation with the bright-rimmed cloud as seen in the optical emission. From the new radio continuum observations, we identify a thin layer of ionized gas located on the border of the clump that is facing the ionizing star. The ionized gas has an electron density of about 73 cm-3, which is a factor three higher than the typical critical density (nc ~ 25 cm-3), above which an ionized boundary layer can be formed and maintained. This supports the hypothesis that the clump is being photoionized by the nearby O9.5V star, BD-14 5014. From the evaluation of the pressure balance between the ionized and molecular gas, we conclude that the clump would be in a prepressure balance

On the Nature and History of Blue Amorphous Galaxies

Science.gov (United States)

Marlowe, Amanda True

1998-07-01

Dwarf galaxies play an important role in our understanding of galaxy formation and evolution. We have embarked on a systematic study of 12 blue amorphous galaxies (BAGs) whose properties suggest that they are dwarf galaxies in a starburst or post-burst state. It seems likely that BAGs are related to other 'starburst' dwarfs such as blue compact dwarfs (BCDs) and HII galaxies. The BAGs in our sample, however, are considerably closer than BCDs and HII galaxies in other samples, and therefore easier to study. These galaxies may offer important insights into dwarf galaxy evolution. In an effort to clarify the role of BAGs in evolutionary scenarios for dwarf galaxies, we present and analyze Hα and UBVI data for our sample. BAGs, like BCDs and HII galaxies, have surface brightness profiles that are exponential in the outer regions but have a predominantly blue central blue excess, suggesting a young burst in an older, redder galaxy. Seven of the galaxies have the bubble or filamentary Hα morphology and double peaked emission lines that are the signature of superbubbles or superwind activity. These galaxies are typically the ones with the strongest central excesses. The starbursting regions are young events compared to the older underlying galaxy, which follow an exponential surface brightness law. Not all of the galaxies develop superwinds: the appearance of superwinds is most sensitive to the concentration and rate of star formation in the starbursting core. The underlying exponential galaxies are very similar to those found in BCDs and HII galaxies, though the 'burst' colors are slightly redder than those found in HII galaxies. BAGs are structurally similar to BCDs and HII galaxies. How BAGs fit into the dwarf galaxy evolutionary debate is less clear. While some compact dIs have properties similar to those of the underlying exponential galaxy in our sample, issues such as mass loss from superwinds, the impact of the starbursting core on the underlying galaxy, and

Bright point study

International Nuclear Information System (INIS)

Tang, F.; Harvey, K.; Bruner, M.; Kent, B.; Antonucci, E.

1982-01-01

Transition region and coronal observations of bright points by instruments aboard the Solar Maximum Mission and high resolution photospheric magnetograph observations on September 11, 1980 are presented. A total of 31 bipolar ephemeral regions were found in the photosphere from birth in 9.3 hours of combined magnetograph observations from three observatories. Two of the three ephemeral regions present in the field of view of the Ultraviolet Spectrometer-Polarimeter were observed in the C IV 1548 line. The unobserved ephemeral region was determined to be the shortest-lived (2.5 hr) and lowest in magnetic flux density (13G) of the three regions. The Flat Crystal Spectrometer observed only low level signals in the O VIII 18.969 A line, which were not statistically significant to be positively identified with any of the 16 ephemeral regions detected in the photosphere. In addition, the data indicate that at any given time there lacked a one-to-one correspondence between observable bright points and photospheric ephemeral regions, while more ephemeral regions were observed than their counterparts in the transition region and the corona

Magnetic fields, velocity fields and brightness in the central region of the Solar disk

Energy Technology Data Exchange (ETDEWEB)

Tsap, T T

1978-01-01

The longitudinal magnetic fields, velocity fields and brightness at the center of the Solar disk are studied. Observations of the magnetic field, line-of-sight velocities and brightness have been made with the doublemagnetograph of the Crimean astrophysical observatory. It is found that the average magnetic field strength recorded in the iron line lambda 5233 A is 18 Gs for the elements of N-polarity and 23 Gs for the elements of S-polarity. The magnetic elements with the field strength more than 200 Gs are observed in some of the cases. There is a close correlation between the magnetic field distribution in the lambda 5250 A FeI and D/sub 1/ Na I lines and between the magnetic field in the lambda 5250 A and brightness in the K/sub 3/CaII line. The dimensions of the magnetic elements in the lambda and D/sub 1/NaI lines are equal. The comparison of the magnetic field with the radial velocity recorded in the lambda 5250 and 5233 A lines has shown that radial velocities are close to zero in the regions of maximum longitudinal magnetic field. The chromospheric network-like pattern is observed in the brightness distribution of ten different spectral lines.

On the Nature of Bright Infrared Sources in the Small Magellanic Cloud: Interpreting MSX through the Lens of Spitzer

Science.gov (United States)

Kraemer, Kathleen E.; Sloan, G. C.

2015-01-01

We compare infrared observations of the Small Magellanic Cloud (SMC) by the Midcourse Space Experiment (MSX) and the Spitzer Space Telescope to better understand what components of a metal-poor galaxy dominate radiative processes in the infrared. The SMC, at a distance of ~60 kpc and with a metallicity of ~0.1-0.2 solar, can serve as a nearby proxy for metal-poor galaxies at high redshift. The MSX Point Source Catalog contains 243 objects in the SMC that were detected at 8.3 microns, the most sensitive MSX band. Multi-epoch, multi-band mapping with Spitzer, supplemented with observations from the Two-Micron All-Sky Survey (2MASS) and the Wide-field Infrared Survey Explorer (WISE), provides variability information, and, together with spectra from Spitzer for ~15% of the sample, enables us to determine what these luminous sources are. How many remain simple point sources? What fraction break up into multiple stars? Which are star forming regions, with both bright diffuse emission and point sources? How do evolved stars and stellar remnants contribute at these wavelengths? What role do young stellar objects and HII regions play? Answering these questions sets the stage for understanding what we will see with the James Webb Space Telescope (JWST).

Photometric behavior of spectral parameters in Vesta dark and bright regions as inferred by the Dawn VIR spectrometer

Science.gov (United States)

Longobardo, Andrea; Palomba, Ernesto; Capaccioni, Fabrizio; De Sanctis, Maria Cristina; Tosi, Federico; Ammannito, Eleonora; Schröder, Stefan E.; Zambon, Francesca; Raymond, Carol A.; Russell, Christopher T.

2014-09-01

NASA’s Dawn spacecraft orbited Vesta for approximately one year, collecting thousands of hyperspectral images of its surface. The mission revealed that Vesta’s surface shows the largest variations in surface albedo on asteroids visited thus far, due to the presence of dark and bright materials at the local scale (i.e. 0.1-10 km). The aim of this work is to characterize the photometric properties of bright and dark regions, and thus derive and apply an empirical photometric correction to all the hyperspectral observations of Vesta. The very large dataset (i.e. more than 20 million spectra) provided by the VIR imaging spectrometer onboard Dawn enabled accurate statistical analysis of the spectral dataset, aimed at retrieving empirical relations between several spectral parameters (i.e. visible and infrared reflectance, band depths, band centers, Band Area Ratio) and the illumination/viewing angles. The derived relations made it possible to derive photometrically corrected maps of these spectral parameters and to infer information on the regolith shadowing effect in the Vestan dark and bright regions. As an additional analysis, we also evaluated the correlation between surface temperature and band center position. A general conclusion of this analysis is that, from a photometric point of view, the distinction between bright and dark material units lies mainly in the larger contribution due to multiple scattering in the bright units. We observed reflectance and band depth variations over Vesta’s entire surface, but these variations were much larger in the dark regions than in the bright ones. Band centers have been found to shift to longer wavelengths at increasing temperatures, with a trend that is the same observed for HED meteorites (Reddy et al. [2012]. Icarus 217, 153-158). Finally, the Band Area Ratio (i.e. the ratio between areas of the main pyroxene absorption bands located at 1.9 μm and at 0.9 μm, respectively) did not show any dependence on

Relationship of magnetic field strength and brightness of fine-structure elements in the solar temperature minimum region

Science.gov (United States)

Cook, J. W.; Ewing, J. A.

1990-01-01

A quantitative relationship was determined between magnetic field strength (or magnetic flux) from photospheric magnetograph observations and the brightness temperature of solar fine-structure elements observed at 1600 A, where the predominant flux source is continuum emission from the solar temperature minimum region. A Kitt Peak magnetogram and spectroheliograph observations at 1600 A taken during a sounding rocket flight of the High Resolution Telescope and Spectrograph from December 11, 1987 were used. The statistical distributions of brightness temperature in the quiet sun at 1600 A, and absolute value of magnetic field strength in the same area were determined from these observations. Using a technique which obtains the best-fit relationship of a given functional form between these two histogram distributions, a quantitative relationship was determined between absolute value of magnetic field strength B and brightness temperature which is essentially linear from 10 to 150 G. An interpretation is suggested, in which a basal heating occurs generally, while brighter elements are produced in magnetic regions with temperature enhancements proportional to B.

Infrared emission from galactic H II regions

International Nuclear Information System (INIS)

Zeilik, M. II.

1975-01-01

Near-infrared observations are presented of selected galactic HII regions (especially G45.5 + 0.1, G45.1 + 0.1, S88, and W3A) to infer the physical conditions of the dust responsible for the 2 to 25 micron emission. Two-component dust models are developed to match the observed characteristics of the infrared emission from HII regions. The dust, assumed to be bare and well-mixed with the gas in the ionized volume, consists of large (0.1 micron) ''silicate'' grains and small (0.2 micron) graphite grains. The ''silicates'' have their cosmic maximum abundance with respect to hydrogen, but the graphite grains are depleted by factors of 25 to 100 in mass. The Lyman-alpha radiation field predominately heats the ''silicate'' grains, which produce almost all the emission at 20 microns and most of it from 8 to 13 microns. The stellar radiation field predominately heats the graphite grains, which generate most of the emission at 3.5 and 5 microns. Roughly half of the observed 2 to 25 micron luminosity (when corrected for extinction) arises from Lyman-alpha photons and the other half from the Lyman and Balmer continua. The grains are too hot to provide significant emission in the far-infrared; this probably arises from a dust shell around the HII region. This two-component model predicts that HII regions should have smaller sizes at 3.5 and 5 microns than at 10 and 20 microns. The emissivities of fine-structure infrared lines for the regions are calculated. In the one instance where observations of such lines have been published (G29.9 - 0.0), predicted emissivities fall below those observed, especially for the 12.86-micron line of NeII. The discrepancy probably arises from an incorrect modeling of the region's ionization structure, but it might also reflect variations in elemental abundances or deficiencies in model stellar atmospheres for hot stars

Far-infrared spectroscopy of HII regions

International Nuclear Information System (INIS)

Emery, R.J.; Kessler, M.F.

1984-01-01

Interest has developed rapidly in the astrophysics associated with far-infrared line emission from ionised regions, following the development of spectroscopic instruments and observing facilities appropriate to those wavelengths. Far-infrared observations and their interpretation are now at the stage where the need for specific developments in theoretical and laboratory work have been identified. The need is also apparent for the development of models dealing with more realistic astrophysical situations. (Auth.)

Observation of near-infrared surface brightness of the large Magellanic cloud

International Nuclear Information System (INIS)

Hayakawa, Satio; Koizumi, Yutaka; Matsumoto, Toshio; Murakami, Hiroshi; Uyama, Kiichiro.

1981-01-01

The near-infrared surface brightness of the large Magellanic cloud was observed by an infrared telescope carried by a balloon. The balloon flight was made at Australian Balloon Launching Station. The brightness distribution of 2.4 Mu m radiation was obtained. A part of Bar was bright, and the expansion of the contour at the east end of Bar corresponded to the 30 Dor region. Many near-infrared sources distribute in this region. Discussions on the color and brightness of the center of Bar and the 30 Dor region are presented. (Kato, T.)

A Substellar Companion to Pleiades HII 3441

Science.gov (United States)

Konishi, Mihoko; Matsuo, Taro; Yamamoto, Kodai; Samland, Matthias; Sudo, Jun; Shibai, Hiroshi; Itoh, Yoichi; Fukagawa, Misato; Sumi, Takhiro; Kudo, Tomoyuki;

The role of the second zero-dispersion wavelength in generation of supercontinua and bright-bright soliton-pairs across the zero-dispersion wavelength: erratum

DEFF Research Database (Denmark)

Frosz, Michael Henoch; Falk, Peter Andreas; Bang, Ole

2007-01-01

An erratum is presented explaining that the observation in the original paper (Optics Express, volume 13, issue 16, page 6181-6192, 2005), of a bright-bright soliton with one color in the anomalous dispersion region and the other color in the normal dispersion region was mistaken; both parts...

Robust brightness enhancement across a luminance range of the glare illusion.

Science.gov (United States)

Tamura, Hideki; Nakauchi, Shigeki; Koida, Kowa

2016-01-01

The glare illusion refers to brightness enhancement and the perception of a self-luminous appearance that occurs when a central region is surrounded by a luminance gradient. The center region appears to be a light source, with its light dispersing into the surrounding region. If the luminous edge is critical for generating the illusion, modulating the perceived luminance of the image, and switching its appearance from luminous to nonluminous, would have a strong impact on lightness and brightness estimation. Here, we quantified the illusion in two ways, by assessing brightness enhancement and examining whether the center region appeared luminous. Thus, we could determine whether the two effects occurred jointly or independently. We examined a wide luminance range of center regions, from 0 to 200% relative to background. Brightness enhancement in the illusion was observed for a wide range of luminances (20% to 200% relative to background), while a luminous-white appearance was observed when the center region luminance was 145% of the background. These results exclude the possibility that brightness enhancement occurs because the stimuli appear self-luminous. We suggest that restoring the original image intensity precedes the perceptual process of lightness estimation.

First ultraviolet observations of the transition regions of X-ray bright solar-type stars in the Pleiades

Science.gov (United States)

Caillault, J.-P.; Vilhu, O.; Linsky, J. L.

1990-01-01

Results are reported from A UV study of the transition regions of two X-ray-bright solar-type stars from the Pleiades, in an attempt to extend the main sequence age baseline for the transition-region activity-age relation over more than two orders of magnitude. However, no emission lines were detected from either star; the upper limits to the fluxes are consistent with previously determined saturation levels, but do not help to further constrain evolutionary models.

Viscosity of HI-I2-H2O solution at atmospheric pressure

International Nuclear Information System (INIS)

Chen, Songzhe; Zhang, Ping; Wang, Laijun; Xu, Jingming; Gao, Mengxue

2014-01-01

Iodine-Sulfur thermochemical cycle (IS-cycle) is one of the most promising massive hydrogen production methods. Basic properties data of the HI-I 2 -H 2 O solution involved in the HI decomposition section of IS-cycle are found to be very important. HI, I 2 , and H 2 O make up a highly non-ideal solution system. Viscosity and its variation with the composition/temperature are very essential for the flowsheet work and HI-H 2 O-I 2 solution’s fluid simulation, especially in the distillation and electro-electrodialysis processes. In this paper, viscosity values of HI-H 2 O-I 2 solutions were measured at atmospheric pressure and varying temperatures (from 20 to 125 ºC). As for the composition, the HI/H2O molar ratio of the samples ranged from 1:5.36 to 1:12.00, while the HI/I 2 molar ratio from 1.0 to 1.4.0. Both temperature and composition have dramatic influence on the viscosity. Increasing temperature or H 2 O/HI molar ratio will lead to the reduction of viscosity; while increasing of I 2 /HI molar ratio results in the increase of viscosity. It was also found that I 2 content has a larger and more complex influence on the viscosity of the HI-H 2 O-I 2 solution than H 2 O content does, especially at low temperature (<50 °C). (author)

Bright point study. [of solar corona

Science.gov (United States)

Tang, F.; Harvey, K.; Bruner, M.; Kent, B.; Antonucci, E.

1982-01-01

Transition region and coronal observations of bright points by instruments aboard the Solar Maximum Mission and high resolution photospheric magnetograph observations on September 11, 1980 are presented. A total of 31 bipolar ephemeral regions were found in the photosphere from birth in 9.3 hours of combined magnetograph observations from three observatories. Two of the three ephemeral regions present in the field of view of the Ultraviolet Spectrometer-Polarimeter were observed in the C IV 1548 line. The unobserved ephemeral region was determined to be the shortest-lived (2.5 hr) and lowest in magnetic flux density (13G) of the three regions. The Flat Crystal Spectrometer observed only low level signals in the O VIII 18.969 A line, which were not statistically significant to be positively identified with any of the 16 ephemeral regions detected in the photosphere. In addition, the data indicate that at any given time there lacked a one-to-one correspondence between observable bright points and photospheric ephemeral regions, while more ephemeral regions were observed than their counterparts in the transition region and the corona.

Star formation and the surface brightness of spiral galaxies

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.

1985-01-01

The (blue) surface brightness of spiral galaxies is significantly correlated with their Hα linewidth. This can be most plausibly interpreted as a correlation of surface brightness with star formation rate. There is also a significant difference in surface brightness between galaxies forming stars in a grand design spiral pattern and those with floc star formation regions. (author)

H2 region detection

International Nuclear Information System (INIS)

Comte, G.

1978-01-01

The now classical technique of detection of HII regions is by means of photography and/or interferometry through narrow-band interference filters, with a large aperture ratio of the imaging optics. It enables the detailed study of the spiral structure and the repartition of ionized gas in our Galaxy as well as in the external galaxies [fr

Electromagnetically induced transparency control in terahertz metasurfaces based on bright-bright mode coupling

Science.gov (United States)

Yahiaoui, R.; Burrow, J. A.; Mekonen, S. M.; Sarangan, A.; Mathews, J.; Agha, I.; Searles, T. A.

2018-04-01

We demonstrate a classical analog of electromagnetically induced transparency (EIT) in a highly flexible planar terahertz metamaterial (MM) comprised of three-gap split-ring resonators. The keys to achieve EIT in this system are the frequency detuning and hybridization processes between two bright modes coexisting in the same unit cell as opposed to bright-dark modes. We present experimental verification of two bright modes coupling for a terahertz EIT-MM in the context of numerical results and theoretical analysis based on a coupled Lorentz oscillator model. In addition, a hybrid variation of the EIT-MM is proposed and implemented numerically to dynamically tune the EIT window by incorporating photosensitive silicon pads in the split gap region of the resonators. As a result, this hybrid MM enables the active optical control of a transition from the on state (EIT mode) to the off state (dipole mode).

Energy-exchange collisions of dark-bright-bright vector solitons.

Science.gov (United States)

Radhakrishnan, R; Manikandan, N; Aravinthan, K

2015-12-01

We find a dark component guiding the practically interesting bright-bright vector one-soliton to two different parametric domains giving rise to different physical situations by constructing a more general form of three-component dark-bright-bright mixed vector one-soliton solution of the generalized Manakov model with nine free real parameters. Moreover our main investigation of the collision dynamics of such mixed vector solitons by constructing the multisoliton solution of the generalized Manakov model with the help of Hirota technique reveals that the dark-bright-bright vector two-soliton supports energy-exchange collision dynamics. In particular the dark component preserves its initial form and the energy-exchange collision property of the bright-bright vector two-soliton solution of the Manakov model during collision. In addition the interactions between bound state dark-bright-bright vector solitons reveal oscillations in their amplitudes. A similar kind of breathing effect was also experimentally observed in the Bose-Einstein condensates. Some possible ways are theoretically suggested not only to control this breathing effect but also to manage the beating, bouncing, jumping, and attraction effects in the collision dynamics of dark-bright-bright vector solitons. The role of multiple free parameters in our solution is examined to define polarization vector, envelope speed, envelope width, envelope amplitude, grayness, and complex modulation of our solution. It is interesting to note that the polarization vector of our mixed vector one-soliton evolves in sphere or hyperboloid depending upon the initial parametric choices.

A simple approach to spectrally resolved fluorescence and bright field microscopy over select regions of interest

OpenAIRE

Dahlberg, Peter D.; Boughter, Christopher T.; Faruk, Nabil F.; Hong, Lu; Koh, Young Hoon; Reyer, Matthew A.; Shaiber, Alon; Sherani, Aiman; Zhang, Jiacheng; Jureller, Justin E.; Hammond, Adam T.

2016-01-01

A standard wide field inverted microscope was converted to a spatially selective spectrally resolved microscope through the addition of a polarizing beam splitter, a pair of polarizers, an amplitude-mode liquid crystal-spatial light modulator, and a USB spectrometer. The instrument is capable of simultaneously imaging and acquiring spectra over user defined regions of interest. The microscope can also be operated in a bright-field mode to acquire absorption spectra of micron scale objects. Th...

MULTI-WAVELENGTH STUDY OF TRANSITION REGION PENUMBRAL SUBARCSECOND BRIGHT DOTS USING IRIS AND NST

Energy Technology Data Exchange (ETDEWEB)

Deng, Na; Liu, Chang; Xu, Yan; Wang, Haimin [Space Weather Research Laboratory, New Jersey Institute of Technology, University Heights, Newark, NJ 07102-1982 (United States); Yurchyshyn, Vasyl [Big Bear Solar Observatory, New Jersey Institute of Technology, 40386 North Shore Lane, Big Bear City, CA 92314-9672 (United States); Tian, Hui [School of Earth and Space Sciences, Peking University, Beijing, 100871 (China); Kleint, Lucia, E-mail: na.deng@njit.edu [University of Applied Sciences and Arts Northwestern Switzerland, Bahnhofstr. 6, 5210 Windisch (Switzerland)

2016-10-01

Using high-resolution transition region (TR) observations taken by the Interface Region Imaging Spectrograph ( IRIS ) mission, Tian et al. revealed numerous short-lived subarcsecond bright dots (BDs) above sunspots (mostly located in the penumbrae), which indicate yet unexplained small-scale energy releases. Moreover, whether or not these subarcsecond TR brightenings have any signature in the lower atmosphere and how they are formed are still not fully resolved. This paper presents a multi-wavelength study of the TR penumbral BDs using a coordinated observation of a near disk center sunspot with IRIS and the 1.6 m New Solar Telescope (NST) at the Big Bear Solar Observatory. NST provides high-resolution chromospheric and photospheric observations with narrowband H α imaging spectroscopy and broadband TiO images, respectively, complementary to IRIS TR observations. A total of 2692 TR penumbral BDs are identified from a 37 minute time series of IRIS 1400 Å slit-jaw images. Their locations tend to be associated more with downflowing and darker fibrils in the chromosphere, and weakly associated with bright penumbral features in the photosphere. However, temporal evolution analyses of the BDs show that there is no consistent and convincing brightening response in the chromosphere. These results are compatible with a formation mechanism of the TR penumbral BDs by falling plasma from coronal heights along more vertical and dense magnetic loops. The BDs may also be produced by small-scale impulsive magnetic reconnection taking place sufficiently high in the atmosphere that has no energy release in the chromosphere.

Selection effects in the bivariate brightness distribution for spiral galaxies

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.

1986-01-01

The joint distribution of total luminosity and characteristic surface brightness (the bivariate brightness distribution) is investigated for a complete sample of spiral galaxies in the Virgo cluster. The influence of selection and physical limits of various kinds on the apparent distribution are detailed. While the distribution of surface brightness for bright galaxies may be genuinely fairly narrow, faint galaxies exist right across the (quite small) range of accessible surface brightnesses so no statement can be made about the true extent of the distribution. The lack of high surface brightness bright galaxies in the Virgo sample relative to an overall RC2 sample (mostly field galaxies) supports the contention that the star-formation rate is reduced in the inner region of the cluster for environmental reasons. (author)

Helmholtz bright and boundary solitons

International Nuclear Information System (INIS)

Christian, J M; McDonald, G S; Chamorro-Posada, P

2007-01-01

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts

ALMA Discovery of Solar Umbral Brightness Enhancement at λ = 3 mm

Energy Technology Data Exchange (ETDEWEB)

Iwai, Kazumasa [Institute for Space-Earth Environmental Research, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 (Japan); Loukitcheva, Maria [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, 323 Martin Luther King Boulevard, Newark, NJ 07102 (United States); Shimojo, Masumi [Chile Observatory, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan); Solanki, Sami K. [Max Planck Institute for Solar System Research, Justus-von-Liebig-Weg 3, D-37073 Göttingen (Germany); White, Stephen M., E-mail: k.iwai@isee.nagoya-u.ac.jp [Space Vehicles Directorate, Air Force Research Laboratory, Albuquerque, NM (United States)

2017-06-01

We report the discovery of a brightness enhancement in the center of a large sunspot umbra at a wavelength of 3 mm using the Atacama Large Millimeter/sub-millimeter Array (ALMA). Sunspots are among the most prominent features on the solar surface, but many of their aspects are surprisingly poorly understood. We analyzed a λ = 3 mm (100 GHz) mosaic image obtained by ALMA that includes a large sunspot within the active region AR12470, on 2015 December 16. The 3 mm map has a 300″ × 300″ field of view and 4.″9 × 2.″2 spatial resolution, which is the highest spatial resolution map of an entire sunspot in this frequency range. We find a gradient of 3 mm brightness from a high value in the outer penumbra to a low value in the inner penumbra/outer umbra. Within the inner umbra, there is a marked increase in 3 mm brightness temperature, which we call an umbral brightness enhancement. This enhanced emission corresponds to a temperature excess of 800 K relative to the surrounding inner penumbral region and coincides with excess brightness in the 1330 and 1400 Å slit-jaw images of the Interface Region Imaging Spectrograph ( IRIS ), adjacent to a partial lightbridge. This λ = 3 mm brightness enhancement may be an intrinsic feature of the sunspot umbra at chromospheric heights, such as a manifestation of umbral flashes, or it could be related to a coronal plume, since the brightness enhancement was coincident with the footpoint of a coronal loop observed at 171 Å.

The bright-bright and bright-dark mode coupling-based planar metamaterial for plasmonic EIT-like effect

Science.gov (United States)

Yu, Wei; Meng, Hongyun; Chen, Zhangjie; Li, Xianping; Zhang, Xing; Wang, Faqiang; Wei, Zhongchao; Tan, Chunhua; Huang, Xuguang; Li, Shuti

2018-05-01

In this paper, we propose a novel planar metamaterial structure for the electromagnetically induced transparency (EIT)-like effect, which consists of a split-ring resonator (SRR) and a pair of metal strips. The simulated results indicate that a single transparency window can be realized in the symmetry situation, which originates from the bright-bright mode coupling. Further, a dual-band EIT-like effect can be achieved in the asymmetry situation, which is due to the bright-bright mode coupling and bright-dark mode coupling, respectively. Different EIT-like effect can be simultaneously achieved in the proposed structure with the different situations. It is of certain significance for the study of EIT-like effect.

The stellar content, metallicity and ionization structure of HII regions

NARCIS (Netherlands)

Martin-Hernandez, NL; Vermeij, R; Tielens, AGGM; van der Hulst, JM; Peeters, E

Observations of infrared fine-structure lines provide direct information on the metallicity and ionization structure of H II regions and indirectly on the hardness of the radiation field ionizing these nebulae. We have analyzed a sample of Galactic and Magellanic Cloud H II regions observed by the

X-ray ionization of the intergalactic medium by quasars

Science.gov (United States)

Graziani, Luca; Ciardi, B.; Glatzle, M.

2018-06-01

We investigate the impact of quasars on the ionization of the surrounding intergalactic medium (IGM) with the radiative transfer code CRASH4, now accounting for X-rays and secondary electrons. After comparing with analytic solutions, we post-process a cosmic volume (≈1.5 × 104 Mpc3h-3) containing a ULAS J1120+0641-like quasar (QSO) hosted by a 5 × 1011M⊙h-1 dark matter (DM) halo. We find that: (i) the average HII region (R ˜ 3.2 pMpc in a lifetime tf = 107 yrs) is mainly set by UV flux, in agreement with semi-analytic scaling relations; (ii) a largely neutral (xHII < 0.001), warm (T ˜ 103 K) tail extends up to few Mpc beyond the ionization front, as a result of the X-ray flux; (iii) LyC-opaque inhomogeneities induce a line of sight (LOS) scatter in R as high as few physical Mpc, consistent with the DLA scenario proposed to explain the anomalous size of the ULAS J1120+0641 ionized region. On the other hand, with an ionization rate \\dot{N}_{γ ,0} ˜ 10^{57} s-1, the assumed DLA clustering and gas opacity, only one LOS shows an HII region compatible with the observed one. We deduce that either the ionization rate of the QSO is at least one order of magnitude lower or the ULAS J1120+0641 bright phase is shorter than 107 yrs.

Measuring brightness temperature distributions of plasma bunches

International Nuclear Information System (INIS)

Kirko, V.I.; Stadnichenko, I.A.

1981-01-01

The possibility of restoration of brightness temperature distribution along plasma jet on the base of a simple ultra high- speed photography and subsequent photometric treatment is shown. The developed technique has been applied for finding spectral radiation intensity and brightness temperature of plasma jets of a tubular gas-cumulative charge and explosive plasma compressor. The problem of shock wave front has been successfully solved and thus distribution of above parameters beginning from the region preceeding the shock wave has been obtained [ru

Micro Coronal Bright Points Observed in the Quiet Magnetic Network by SOHO/EIT

Science.gov (United States)

Falconer, D. A.; Moore, R. L.; Porter, J. G.

1997-01-01

When one looks at SOHO/EIT Fe XII images of quiet regions, one can see the conventional coronal bright points (> 10 arcsec in diameter), but one will also notice many smaller faint enhancements in brightness (Figure 1). Do these micro coronal bright points belong to the same family as the conventional bright points? To investigate this question we compared SOHO/EIT Fe XII images with Kitt Peak magnetograms to determine whether the micro bright points are in the magnetic network and mark magnetic bipoles within the network. To identify the coronal bright points, we applied a picture frame filter to the Fe XII images; this brings out the Fe XII network and bright points (Figure 2) and allows us to study the bright points down to the resolution limit of the SOHO/EIT instrument. This picture frame filter is a square smoothing function (hlargelyalf a network cell wide) with a central square (quarter of a network cell wide) removed so that a bright point's intensity does not effect its own background. This smoothing function is applied to the full disk image. Then we divide the original image by the smoothed image to obtain our filtered image. A bright point is defined as any contiguous set of pixels (including diagonally) which have enhancements of 30% or more above the background; a micro bright point is any bright point 16 pixels or smaller in size. We then analyzed the bright points that were fully within quiet regions (0.6 x 0.6 solar radius) centered on disk center on six different days.

A radio continuum and infrared study of Galactic HII regions

NARCIS (Netherlands)

Martin-Hernandez, NL; van der Hulst, JM; Tielens, AGGM

We present observations of the 4.8 and 8.6 GHz continuum emission towards 11 southern H II regions made with the Australian Telescope Compact Array. The observed objects were selected from the Infrared Space Observatory (ISO) spectral catalogue of compact H II regions (Peeters et al. 2002b). The

Helmholtz bright and boundary solitons

Energy Technology Data Exchange (ETDEWEB)

Christian, J M [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); McDonald, G S [Joule Physics Laboratory, School of Computing, Science and Engineering, Institute for Materials Research, University of Salford, Salford M5 4WT (United Kingdom); Chamorro-Posada, P [Departmento de TeorIa de la Senal y Comunicaciones e IngenierIa Telematica, Universidad de Valladolid, ETSI Telecomunicacion, Campus Miguel Delibes s/n, 47011 Valladolid (Spain)

2007-02-16

We report, for the first time, exact analytical boundary solitons of a generalized cubic-quintic nonlinear Helmholtz (NLH) equation. These solutions have a linked-plateau topology that is distinct from conventional dark soliton solutions; their amplitude and intensity distributions are spatially delocalized and connect regions of finite and zero wave-field disturbances (suggesting also the classification as 'edge solitons'). Extensive numerical simulations compare the stability properties of recently derived Helmholtz bright solitons, for this type of polynomial nonlinearity, to those of the new boundary solitons. The latter are found to possess a remarkable stability characteristic, exhibiting robustness against perturbations that would otherwise lead to the destabilizing of their bright-soliton counterparts.

Low surface brightness galaxies in the cluster A1367

International Nuclear Information System (INIS)

Davies, J.I.; Phillipps, S.; Disney, M.J.

1989-01-01

We have obtained deep CCD frames of apparently blank regions of sky in the hope of detecting very low surface brightness (LSB) objects in the cluster A1367. We discuss our data reduction, and image detection and selection techniques. If the galaxies detected are actually cluster members then they are dwarfs and the conclusions of a previous paper on the Fornax cluster are essentially confirmed. One area of variance is that the lowest surface brightness galaxies do not appear to be preferentially concentrated towards the cluster centre. This can be explained by there being a much larger density of dwarf galaxies over this bright galaxy-rich region of the universe. We find over our small area approximately four times as many LSB galaxies as would be expected from our Fornax data. We speculate on the possible origin and likely intensity of intergalactic light within clusters. (author)

Plasmonic EIT-like switching in bright-dark-bright plasmon resonators.

Science.gov (United States)

Chen, Junxue; Wang, Pei; Chen, Chuncong; Lu, Yonghua; Ming, Hai; Zhan, Qiwen

2011-03-28

In this paper we report the study of the electromagnetically induced transparency (EIT)-like transmission in the bright-dark-bright plasmon resonators. It is demonstrated that the interferences between the dark plasmons excited by two bright plasmon resonators can be controlled by the incident light polarization. The constructive interference strengthens the coupling between the bright and dark resonators, leading to a more prominent EIT-like transparency window of the metamaterial. In contrary, destructive interference suppresses the coupling between the bright and dark resonators, destroying the interference pathway that forms the EIT-like transmission. Based on this observation, the plasmonic EIT switching can be realized by changing the polarization of incident light. This phenomenon may find applications in optical switching and plasmon-based information processing.

Low surface brightness galaxies in the Fornax Cluster: automated galaxy surface photometry

International Nuclear Information System (INIS)

Davies, J.I.; Phillipps, S.; Disney, M.J.

1988-01-01

A sample is presented of low surface brightness galaxies (with extrapolated central surface brightness fainter than 22.0 Bμ) in the Fornax Cluster region which has been measured by the APM machine. Photometric parameters, namely profile shape, scale length, central brightness and total magnitude, are derived for the sample galaxies and correlations between the parameters of low surface brightness dwarf galaxies are discussed, with particular reference to the selection limits. Contrary to previous authors we find no evidence for a luminosity-surface brightness correlation in the sense of lower surface brightness galaxies having lower luminosities and scale sizes. In fact, the present data suggest that it is the galaxies with the largest scale lengths which are more likely to be of very low surface brightness. In addition, the larger scale length galaxies occur preferentially towards the centre of the Cluster. (author)

Energy and Emission Characteristics of a Short-Arc Xenon Flash Lamp Under "Saturated" Optical Brightness Conditions

Science.gov (United States)

Kamrukov, A. S.; Kireev, S. G.; Kozlov, N. P.; Shashkovskii, S. G.

2017-09-01

We present the results of a study of the electrical, energy, and spectral brightness characteristics of an experimental three-electrode high-pressure xenon flash lamp under conditions ensuring close to maximum possible spectral brightness for the xenon emission. We show that under saturated optical brightness conditions (brightness temperature in the visible region of the spectrum 30,000 K), emission of a pulsed discharge in xenon is quite different from the emission from an ideal blackbody: the maximum brightness temperatures are 24,000 K in the short-wavelength UV region and 19,000 K in the near IR range. The relative fraction of UV radiation in the emission spectrum of the lamp is >50%, which lets us consider such lamps as promising broadband sources of radiation with high spectral brightness for many important practical applications.

A high brightness probe of polymer nanoparticles for biological imaging

Science.gov (United States)

Zhou, Sirong; Zhu, Jiarong; Li, Yaping; Feng, Liheng

2018-03-01

Conjugated polymer nanoparticles (CPNs) with high brightness in long wavelength region were prepared by the nano-precipitation method. Based on fluorescence resonance energy transfer (FRET) mechanism, the high brightness property of the CPNs was realized by four different emission polymers. Dynamic light scattering (DLS) and scanning electron microscopy (SEM) displayed that the CPNs possessed a spherical structure and an average diameter of 75 nm. Analysis assays showed that the CPNs had excellent biocompatibility, good photostability and low cytotoxicity. The CPNs were bio-modified with a cell penetrating peptide (Tat, a targeted element) through covalent link. Based on the entire wave fluorescence emission, the functionalized CPNs1-4 can meet multichannel and high throughput assays in cell and organ imaging. The contribution of the work lies in not only providing a new way to obtain a high brightness imaging probe in long wavelength region, but also using targeted cell and organ imaging.

Orientation of coronal bright points and small-scale magnetic bipoles

International Nuclear Information System (INIS)

MINENKO, E.P.; SHERDANOV, CH.T.; SATTAROV, I.; KARACHIK, N.V.

2014-01-01

Using the observations from Extreme-Ultraviolet Imaging Telescope (EIT) on the SOHO board and longitudinal full-disk magnetograms (vector spectromagnetograph - VSM) from the Synoptic Optical Long-Term Investigations of the Sun (SOLIS), we explore the orientation and relationship between the coronal bright points at 195 A o (hereafter CBPs) and magnetic bipoles (only for the central zone of solar disk). The magnetic bipoles are identified as a pair of streams of positive and negative polarities with a shortest distance between them. This paper presents a study of the structure and orientation (angles) of magnetic bipoles to the solar equator and two types of CBPs: 'dim' CBPs in the quiet regions of the Sun and 'bright' CBPs associated with active regions. For these magnetic bipoles associated with 'bright' CBPs, we find that their orientation angles are distributed randomly along the equator. (authors)

Bright galaxies in the Fornax cluster. Automated galaxy surface photometry: Pt. 7

International Nuclear Information System (INIS)

Disney, M.J.; Phillipps, S.; Davies, J.L.; Cawson, M.G.M.; Kibblewhite, E.J.

1990-01-01

We have determined surface-brightness profiles for all galaxies down to magnitude B = 16 in the central region of the Fornax cluster. Using existing redshift data, we have determined the distributions of surface brightness for both the whole sample and for cluster disc galaxies only. Although both distributions peak at extrapolated central surface brightness ∼ 21.7B mag/arcsec 2 (the canonical result), it is shown that they are, in fact, consistent with very broad distributions of disc central surface brightness once selection effects and the effects of bulge contamination of the profile are taken into account. (author)

Analysis Of Ultra Compact Ionized Hydrogen Regions Within The Northern Half Of The Galactic Disk

Science.gov (United States)

Bruce, John

2011-01-01

From a catalog of 199 candidate ultra compact (UC) HII regions 123 sources included in the the intersection of the GLIMPSE (8 μm),Cornish (6 cm), and Bolocam ( 1.1 mm) galactic plane surveys (BGPS) were analyzed. The sources were sorted based on 6 cm morphology and coincidence with 8 μm bubbles. The 1.1 mm flux attributes were measured and calculations were performed to determine the ionized hydrogen contributions to the 1.1 mm flux. The category averages and frequencies were obtained as well. Significant differences in HII percentages were present among the morphology groups but ranged widely, without apparent distinction, between the bubble forming and triggered source categories.

A spectral k-means approach to bright-field cell image segmentation.

Science.gov (United States)

Bradbury, Laura; Wan, Justin W L

2010-01-01

Automatic segmentation of bright-field cell images is important to cell biologists, but difficult to complete due to the complex nature of the cells in bright-field images (poor contrast, broken halo, missing boundaries). Standard approaches such as level set segmentation and active contours work well for fluorescent images where cells appear as round shape, but become less effective when optical artifacts such as halo exist in bright-field images. In this paper, we present a robust segmentation method which combines the spectral and k-means clustering techniques to locate cells in bright-field images. This approach models an image as a matrix graph and segment different regions of the image by computing the appropriate eigenvectors of the matrix graph and using the k-means algorithm. We illustrate the effectiveness of the method by segmentation results of C2C12 (muscle) cells in bright-field images.

Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise.

Science.gov (United States)

Youngstedt, Shawn D; Kline, Christopher E; Elliott, Jeffrey A; Zielinski, Mark R; Devlin, Tina M; Moore, Teresa A

2016-02-26

Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210-2340 h, (2) treadmill exercise alone from 2210-2340 h, or (3) bright light (2210-2340 h) followed by exercise from 0410-0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect.

Measuring and mapping the night sky brightness of Perth, Western Australia

Science.gov (United States)

Biggs, James D.; Fouché, Tiffany; Bilki, Frank; Zadnik, Marjan G.

2012-04-01

In order to study the light pollution produced in the city of Perth, Western Australia, we have used a hand-held sky brightness meter to measure the night sky brightness across the city. The data acquired facilitated the creation of a contour map of night sky brightness across the 2400 km2 area of the city - the first such map to be produced for a city. Importantly, this map was created using a methodology borrowed from the field of geophysics - the well proven and rigorous techniques of geostatistical analysis and modelling. A major finding of this study is the effect of land use on night sky brightness. By overlaying the night sky brightness map on to a suitably processed Landsat satellite image of Perth we found that locations near commercial and/or light industrial areas have a brighter night sky, whereas locations used for agriculture or having high vegetation coverage have a fainter night sky than surrounding areas. Urban areas have intermediate amounts of vegetation and are intermediate in brightness compared with the above-mentioned land uses. Regions with a higher density of major highways also appear to contribute to increased night sky brightness. When corrected for the effects of direct illumination from high buildings, we found that the night sky brightness in the central business district (CBD) is very close to that expected for a city of Perth's population from modelling work and observations obtained in earlier studies. Given that our night sky brightness measurements in Perth over 2009 and 2010 are commensurate with that measured in Canadian cities over 30 years earlier implies that the various lighting systems employed in Perth (and probably most other cities) have not been optimised to minimize light pollution over that time. We also found that night sky brightness diminished with distance with an exponent of approximately -0.25 ± 0.02 from 3.5 to 10 km from the Perth CBD, a region characterized by urban and commercial land use. For distances

A Distributed Public Key Infrastructure Based on Threshold Cryptography for the HiiMap Next Generation Internet Architecture

Directory of Open Access Journals (Sweden)

Oliver Hanka

2011-02-01

Full Text Available In this article, a security extension for the HiiMap Next Generation Internet Architecture is presented. We regard a public key infrastructure which is integrated into the mapping infrastructure of the locator/identifier-split addressing scheme. The security approach is based on Threshold Cryptography which enables a sharing of keys among the mapping servers. Hence, a more trustworthy and fair approach for a Next Generation Internet Architecture as compared to the state of the art approach is fostered. Additionally, we give an evaluation based on IETF AAA recommendations for security-related systems.

150 southern compact and bright-nucleus galaxies

International Nuclear Information System (INIS)

Fairall, A.P.

1977-01-01

Galaxies having regions of exceptionally high surface brightness have been selected from the ESO Quick Blue Survey and investigated by 'grating photography' -direct photography plus low-dispersion slitless spectroscopy. Two new Seyfert galaxies and a peculiar multiple system have been discovered. Differences in red continua are also noted. (author)

Impact of climate change on the Hii River basin and salinity in Lake Shinji: a case study using the SWAT model and a regression curve

Science.gov (United States)

The impacts of climate change on water resources were analysed for the Hii River basin and downstream Lake Shinji. The variation between saline and fresh water within these systems means that they encompass diverse ecosystems. Changes in evapotranspiration (ET), snow water equivalent, discharge into...

Ultrahigh-brightness KrF laser system for fast ignition studies

International Nuclear Information System (INIS)

Shaw, M.J.; Ross, I.N.; Hooker, C.J.; Dodson, J.M.; Hirst, G.J.; Lister, J.M.D.; Divall, E.J.; Kidd, A.K.; Hancock, S.; Damerell, A.R.; Wyborn, B.E.

1999-01-01

The main requirements for a fast igniter laser beam are reviewed and shown to favour short wavelength and ultrahigh brightness. These requirements are met by the new KrF laser system at Rutherford Appleton Laboratory called TITANIA. TITANIA uses two schemes to enhance the laser beam brightness. The first is chirped pulse amplification which is used to enhance brightness by compressing the pulse into the femtosecond region. In this mode TITANIA produces in the region of 250 mJ on target in 700 fs. The second mode of operation uses a Raman technique for beam combining and beam clean-up which is designed to give a single beam of 80 Joules on target in a pulselength of 60 ps. In this scheme the KrF wavelength is Raman shifted to 268 nm. The Raman amplifiers will use gaseous rather than solid windows and experiments which demonstrate their feasibility will be described. A concept for a reactor scale fast igniter beam using the Raman technique will be discussed. (orig.)

Addressing Ionization and Depletion in the ISM of Nearby Star-Forming Galaxies

Science.gov (United States)

Aloisi, Alessandra

2017-08-01

Measuring galaxy metallicity with cosmic time is of paramount importance to understand galaxy formation. ISM abundances are typically determined using emission-line spectroscopy of HII regions. However, HII regions may be self-enriched and not typical of the whole galaxy. This is particularly true for star-forming galaxies (SFGs) where the bulk of metals may be in the neutral gas. Quantifying metals in the ISM is thus important to assess how reliably HII regions trace galaxy abundances at any redshift. We were awarded 34 HST orbits (Cycle 17) to measure abundances in the neutral ISM of 9 nearby SFGs using absorption lines in the COS G130M/1291 spectra of bright UV background sources within the galaxy itself. We found metallicities that differ by up to 2 dex depending on the element. These variations could be real or due to observational effects. Here we request 22 orbits in the new G130M/1222 and in G160M/1623 to access new FUV spectral transitions that will help us characterize ionized-gas contamination and dust depletion, and ultimately nail down the abundances of the different elements. These new data will nicely complement our Cycle 17 COS and Gemini/GMOS IFU programs, the latter aimed at deriving nebular abundances along the same COS sightlines. This first detailed and spatially-accurate comparison between neutral- and ionized-gas abundances in local (z 0) SFGs will provide crucial insights into the metallicity of galaxies at any redshift. If this UV spectroscopic study is not undertaken before HST ceases operation, the (in)homogeneity of the ISM in galaxies of the local Universe will continue to remain uncertain for at least another decade.

Spotted star light curve numerical modeling technique and its application to HII 1883 surface imaging

Science.gov (United States)

Kolbin, A. I.; Shimansky, V. V.

2014-04-01

We developed a code for imaging the surfaces of spotted stars by a set of circular spots with a uniform temperature distribution. The flux from the spotted surface is computed by partitioning the spots into elementary areas. The code takes into account the passing of spots behind the visible stellar limb, limb darkening, and overlapping of spots. Modeling of light curves includes the use of recent results of the theory of stellar atmospheres needed to take into account the temperature dependence of flux intensity and limb darkening coefficients. The search for spot parameters is based on the analysis of several light curves obtained in different photometric bands. We test our technique by applying it to HII 1883.

Kiloamp high-brightness beams

International Nuclear Information System (INIS)

Caporaso, G.J.

1987-01-01

Brightness preservation of high-current relativistic electron beams under two different types of transport is discussed. Recent progress in improving the brightness of laser-guided beams in the Advanced Test Accelerator is reviewed. A strategy for the preservation of the brightness of space-charge-dominated beams in a solenoidal transport system is presented

The Wolf-Rayet eclipsing binary HD 5980 in the Small Magellanic Cloud

International Nuclear Information System (INIS)

Breysacher, J.; Moffat, A.F.J.

1982-01-01

The Wolf-Rayet star HD 5980, which is probably associated with the bright HII region NGC 346 of the Small Magellanic Cloud, was found to be an eclipsing binary by Hoffmann, Stift and Moffat (1978). Breysacher and Perrier (1980) determined the orbital period, P=19.26 +- 0.003d, of the system whose light curve reveals a strongly eccentric orbit (e=0.47 for i=80 0 ). The behaviour of the light curve outside the eclipses shows that one is dealing with a rather complex binary system. An analysis of the spectroscopic data is presented here. (Auth.)

HII 2407: AN ECLIPSING BINARY REVEALED BY K2 OBSERVATIONS OF THE PLEIADES

Energy Technology Data Exchange (ETDEWEB)

David, Trevor J.; Hillenbrand, Lynne A.; Zhang, Celia; Riddle, Reed L. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Stauffer, John; Rebull, L. M. [Spitzer Science Center, California Institute of Technology, Pasadena, CA 91125 (United States); Cody, Ann Marie [NASA Ames Research Center, Mountain View, CA 94035 (United States); Conroy, Kyle; Stassun, Keivan G. [Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235 (United States); Pope, Benjamin; Aigrain, Suzanne; Gillen, Ed [Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH (United Kingdom); Cameron, Andrew Collier [SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY16 9SS (United Kingdom); Barrado, David [Centro de Astrobiología, INTA-CSIC, Dpto. Astrofísica, ESAC Campus, P.O. Box 78, E-28691 Villanueva de la Cañada, Madrid (Spain); Isaacson, Howard; Marcy, Geoffrey W. [Department of Astronomy, University of California, Berkeley, CA 94720 (United States); Ziegler, Carl; Law, Nicholas M. [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3255 (United States); Baranec, Christoph, E-mail: tjd@astro.caltech.edu [Institute for Astronomy, University of Hawai‘i at Mānoa, Hilo, HI 96720-2700 (United States)

2015-11-20

The star HII 2407 is a member of the relatively young Pleiades star cluster and was previously discovered to be a single-lined spectroscopic binary. It is newly identified here within Kepler/K2 photometric time series data as an eclipsing binary system. Mutual fitting of the radial velocity and photometric data leads to an orbital solution and constraints on fundamental stellar parameters. While the primary has arrived on the main sequence, the secondary is still pre-main sequence and we compare our results for the M/M{sub ⊙} and R/R{sub ⊙} values with stellar evolutionary models. We also demonstrate that the system is likely to be tidally synchronized. Follow-up infrared spectroscopy is likely to reveal the lines of the secondary, allowing for dynamically measured masses and elevating the system to benchmark eclipsing binary status.

A selective deficit in the appreciation and recognition of brightness: brightness agnosia?

Science.gov (United States)

Nijboer, Tanja C W; Nys, Gudrun M S; van der Smagt, Maarten J; de Haan, Edward H F

2009-01-01

We report a patient with extensive brain damage in the right hemisphere who demonstrated a severe impairment in the appreciation of brightness. Acuity, contrast sensitivity as well as luminance discrimination were normal, suggesting her brightness impairment is not a mere consequence of low-level sensory impairments. The patient was not able to indicate the darker or the lighter of two grey squares, even though she was able to see that they differed. In addition, she could not indicate whether the lights in a room were switched on or off, nor was she able to differentiate between normal greyscale images and inverted greyscale images. As the patient recognised objects, colours, and shapes correctly, the impairment is specific for brightness. As low-level, sensory processing is normal, this specific deficit in the recognition and appreciation of brightness appears to be of a higher, cognitive level, the level of semantic knowledge. This appears to be the first report of 'brightness agnosia'.

IRAS colors of VLA identified objects in the galaxy

International Nuclear Information System (INIS)

Fich, M.; Terebey, S.

1987-01-01

Infrared Astronomy Satellite (IRAS) sources found within 4 degrees of l = 125 deg, b = 2 deg on the 3rd HCON 60 micron Sky Brightness Images were observed at the Very Large Array (VLA). Regions were to be identified where massive stars are forming by looking for small areas of radio continuum emissions. The IRAS sources could be divided into three groups by their IRAS 12 micron/25 micron and 60 micron/100 micron color. The group identified with star forming regions contained essentially all of the objects with extended radio emission. In all of these cases the extended radio emission showed a morphology consistent with the identification of these objects as HII regions. The conclusion drawn is that star formation regions can be distinguished from other objects by their infrared colors

Experimental study of the vapour-liquid equilibria of HI-I-2-H2O ternary mixtures, Part 2: Experimental results at high temperature and pressure

International Nuclear Information System (INIS)

Larousse, B.; Lovera, P.; Borgard, J.M.; Roehrich, G.; Mokrani, N.; Maillault, C.; Doizi, D.; Dauvois, V.; Roujou, J.L.; Lorin, V.; Fauvet, P.; Carles, P.; Hartmann, J.M.

2009-01-01

In order to assess the choice of the sulphur-iodine thermochemical cycle for massive hydrogen production, a precise knowledge of the concentrations of the gaseous species (HI, I 2 , and H 2 O) in thermodynamic equilibrium with the liquid phase of the HI-I 2 -H 2 O ternary mixture is required, in a wide range of concentrations and for temperatures and pressures up to 300 degrees C and 50 bar. In the companion paper (Part 1) the experimental device was described, which enables the measurement of the total pressure and concentrations of the vapour phase (and thus the knowledge of the partial pressures of the different gaseous species) for the HI-I 2 -H 2 O mixture in the 20-140 degrees C range and up to 2 bar. This (Part 2) article describes the experimental device which enables similar measurements but now in the process domain. The results concerning concentrations in the vapour phase for the HI-I 2 -H 2 O initial mixture (with a global composition) in the 120-270 degrees C temperature range and up to 30 bar are presented. As previously, optical online diagnostics are used, based on recordings of infrared transmission spectra for HI and H 2 O and on UV/visible spectrometry for I 2 . The concentrations measured in the vapour phase are the first to describe the vapour composition under thermophysical conditions close to those of the distillation column. The experimental results are compared with a thermodynamic model and will help us to scale up and optimize the reactive distillation column we promote for the HI section of the sulphur-iodine cycle. (authors)

BrightFocus Foundation

Science.gov (United States)

... About BrightFocus Foundation Featured Content BrightFocus: Investing in Science to Save Mind and Sight We're here to help. Explore ... recognition is very important. Monday, November 6, 2017 New Diagnosis? Managing a mind and sight disease is a journey. And you’ ...

Condensate bright solitons under transverse confinement

International Nuclear Information System (INIS)

Salasnich, L.; Reatto, L.; Parola, A.

2002-01-01

We investigate the dynamics of Bose-Einstein condensate bright solitons made of alkali-metal atoms with negative scattering length and under harmonic confinement in the transverse direction. Contrary to the one-dimensional (1D) case, the 3D bright soliton exists only below a critical attractive interaction that depends on the extent of confinement. Such a behavior is also found in multisoliton condensates with box boundary conditions. We obtain numerical and analytical estimates of the critical strength beyond which the solitons do not exist. By using an effective 1D nonpolynomial nonlinear Schroedinger equation, which accurately takes into account the transverse dynamics of cigarlike condensates, we numerically simulate the dynamics of the 'soliton train' reported in a recent experiment [Nature (London) 417, 150 (2002)]. Then, analyzing the macroscopic quantum tunneling of the bright soliton on a Gaussian barrier, we find that its interference in the tunneling region is strongly suppressed with respect to nonsolitonic case; moreover, the tunneling through a barrier breaks the shape invariance of the matter wave. Finally, we show that the collapse of the soliton is induced by the scattering on the barrier or by the collision with another matter wave when the density reaches a critical value, for which we derive an accurate analytical formula

Possible Bright Starspots on TRAPPIST-1

Science.gov (United States)

Morris, Brett M.; Agol, Eric; Davenport, James R. A.; Hawley, Suzanne L.

2018-04-01

The M8V star TRAPPIST-1 hosts seven roughly Earth-sized planets and is a promising target for exoplanet characterization. Kepler/K2 Campaign 12 observations of TRAPPIST-1 in the optical show an apparent rotational modulation with a 3.3-day period, though that rotational signal is not readily detected in the Spitzer light curve at 4.5 μm. If the rotational modulation is due to starspots, persistent dark spots can be excluded from the lack of photometric variability in the Spitzer light curve. We construct a photometric model for rotational modulation due to photospheric bright spots on TRAPPIST-1 that is consistent with both the Kepler and Spitzer light curves. The maximum-likelihood model with three spots has typical spot sizes of R spot/R ⋆ ≈ 0.004 at temperature T spot ≳ 5300 ± 200 K. We also find that large flares are observed more often when the brightest spot is facing the observer, suggesting a correlation between the position of the bright spots and flare events. In addition, these flares may occur preferentially when the spots are increasing in brightness, which suggests that the 3.3-day periodicity may not be a rotational signal, but rather a characteristic timescale of active regions.

Effects of background and contour luminance on the hue and brightness of the Watercolor effect.

Science.gov (United States)

Gerardin, Peggy; Dojat, Michel; Knoblauch, Kenneth; Devinck, Frédéric

2018-03-01

Conjoint measurement was used to investigate the joint influences of the luminance of the background and the inner contour on hue- and brightness filling-in for a stimulus configuration generating a water-color effect (WCE), i.e., a wiggly bi-chromatic contour enclosing a region with the lower luminance component on the exterior. Two stimuli with the background and inner contour luminances covarying independently were successively presented, and in separate experiments, the observer judged which member of the pair's interior regions contained a stronger hue or was brighter. Braided-contour control stimuli that generated little or no perceptual filling-in were also used to assess whether observers were judging the interior regions and not the contours themselves. Three nested models of the contributions of the background and inner contour to the judgments were fit to the data by maximum likelihood and evaluated by likelihood ratio tests. Both stimulus components contributed to both the hue and brightness of the interior region with increasing luminance of the inner contour generating an assimilative filling-in for the hue judgments but a contrast effect for the brightness judgments. Control analyses showed negligible effects for the order of the luminance of the background or inner contour on the judgments. An additive contribution of both components was rejected in favor of a saturated model in which the responses depended on the levels of both stimulus components. For the hue judgments, increased background luminance led to greater hue filling-in at higher luminances of the interior contour. For the brightness judgments, the higher background luminance generated less brightness filling-in at higher luminances of the interior contour. The results indicate different effects of the inner contour and background on the induction of the brightness and coloration percepts of the WCE, suggesting that they are mediated by different mechanisms. Copyright © 2018 Elsevier

Characterizing the zenithal night sky brightness in large territories: how many samples per square kilometre are needed?

Science.gov (United States)

Bará, Salvador

2018-01-01

A recurring question arises when trying to characterize, by means of measurements or theoretical calculations, the zenithal night sky brightness throughout a large territory: how many samples per square kilometre are needed? The optimum sampling distance should allow reconstructing, with sufficient accuracy, the continuous zenithal brightness map across the whole region, whilst at the same time avoiding unnecessary and redundant oversampling. This paper attempts to provide some tentative answers to this issue, using two complementary tools: the luminance structure function and the Nyquist-Shannon spatial sampling theorem. The analysis of several regions of the world, based on the data from the New world atlas of artificial night sky brightness, suggests that, as a rule of thumb, about one measurement per square kilometre could be sufficient for determining the zenithal night sky brightness of artificial origin at any point in a region to within ±0.1 magV arcsec-2 (in the root-mean-square sense) of its true value in the Johnson-Cousins V band. The exact reconstruction of the zenithal night sky brightness maps from samples taken at the Nyquist rate seems to be considerably more demanding.

Fifty shades of white: how white feather brightness differs among species

Science.gov (United States)

Igic, Branislav; D'Alba, Liliana; Shawkey, Matthew D.

2018-04-01

White colouration is a common and important component of animal visual signalling and camouflage, but how and why it varies across species is poorly understood. White is produced by wavelength-independent and diffuse scattering of light by the internal structures of materials, where the degree of brightness is related to the amount of light scattered. Here, we investigated the morphological basis of brightness differences among unpigmented pennaceous regions of white body feathers across 61 bird species. Using phylogenetically controlled comparisons of reflectance and morphometric measurements, we show that brighter white feathers had larger and internally more complex barbs than duller white feathers. Higher brightness was also associated with more closely packed barbs and barbules, thicker and longer barbules, and rounder and less hollow barbs. Larger species tended to have brighter white feathers than smaller species because they had thicker and more complex barbs, but aquatic species were not significantly brighter than terrestrial species. As similar light scattering principals affect the brightness of chromatic signals, not just white colours, these findings help broaden our general understanding of the mechanisms that affect plumage brightness. Future studies should examine how feather layering on a bird's body contributes to differences between brightness of white plumage patches within and across species.

Search for bright stars with infrared excess

Energy Technology Data Exchange (ETDEWEB)

Raharto, Moedji, E-mail: moedji@as.itb.ac.id [Astronomy Research Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia)

2014-03-24

Bright stars, stars with visual magnitude smaller than 6.5, can be studied using small telescope. In general, if stars are assumed as black body radiator, then the color in infrared (IR) region is usually equal to zero. Infrared data from IRAS observations at 12 and 25μm (micron) with good flux quality are used to search for bright stars (from Bright Stars Catalogues) with infrared excess. In magnitude scale, stars with IR excess is defined as stars with IR color m{sub 12}−m{sub 25}>0; where m{sub 12}−m{sub 25} = −2.5log(F{sub 12}/F{sub 25})+1.56, where F{sub 12} and F{sub 25} are flux density in Jansky at 12 and 25μm, respectively. Stars with similar spectral type are expected to have similar color. The existence of infrared excess in the same spectral type indicates the existence of circum-stellar dust, the origin of which is probably due to the remnant of pre main-sequence evolution during star formation or post AGB evolution or due to physical process such as the rotation of those stars.

The surface brightness of 1550 galaxies in Fornax: automated galaxy surface photometry: Pt. 2

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.J.; Kibblewhite, E.J.; Cawson, M.G.M.

1987-01-01

A survey of a complete sample of galaxies in the region of the Fornax cluster is presented. Measurements with the Automatic Plate Measuring machine are used to derive the observed distribution of galaxy surface brightness for 1550 objects. Corrections for surface brightness dependent selection effects are then made in order to estimate the true distribution. It is found that the sample (with 16.6 ≤ Msub(APM) ≤ 19.1) is divided into two distinct populations. The 'normal' galaxies with extrapolated central surface brightness Ssub(x) ≤ 22.5 Bμ form a uniformly distributed background of field galaxies. Low surface brightness galaxies (Ssub(x) ≥ 22.5 Bμ), on the other hand, are strongly clumped about the cluster centre. There appear to be few low surface brightness field galaxies. (author)

Thermal measurements of dark and bright surface features on Vesta as derived from Dawn/VIR

Science.gov (United States)

Tosi, Federico; Capria, Maria Teresa; De Sanctis, M.C.; Combe, J.-Ph.; Zambon, F.; Nathues, A.; Schröder, S.E.; Li, J.-Y.; Palomba, E.; Longobardo, A.; Blewett, D.T.; Denevi, B.W.; Palmer, E.; Capaccioni, F.; Ammannito, E.; Titus, Timothy N.; Mittlefehldt, D.W.; Sunshine, J.M.; Russell, C.T.; Raymond, C.A.; Dawn/VIR Team,

2014-01-01

Remote sensing data acquired during Dawn’s orbital mission at Vesta showed several local concentrations of high-albedo (bright) and low-albedo (dark) material units, in addition to spectrally distinct meteorite impact ejecta. The thermal behavior of such areas seen at local scale (1-10 km) is related to physical properties that can provide information about the origin of those materials. We use Dawn’s Visible and InfraRed (VIR) mapping spectrometer hyperspectral data to retrieve surface temperatures and emissivities, with high accuracy as long as temperatures are greater than 220 K. Some of the dark and bright features were observed multiple times by VIR in the various mission phases at variable spatial resolution, illumination and observation angles, local solar time, and heliocentric distance. This work presents the first temperature maps and spectral emissivities of several kilometer-scale dark and bright material units on Vesta. Results retrieved from the infrared data acquired by VIR show that bright regions generally correspond to regions with lower temperature, while dark regions correspond to areas with higher temperature. During maximum daily insolation and in the range of heliocentric distances explored by Dawn, i.e. 2.23-2.54 AU, the warmest dark unit found on Vesta rises to a temperature of 273 K, while bright units observed under comparable conditions do not exceed 266 K. Similarly, dark units appear to have higher emissivity on average compared to bright units. Dark-material units show a weak anticorrelation between temperature and albedo, whereas the relation is stronger for bright material units observed under the same conditions. Individual features may show either evanescent or distinct margins in the thermal images, as a consequence of the cohesion of the surface material. Finally, for the two categories of dark and bright materials, we were able to highlight the influence of heliocentric distance on surface temperatures, and estimate an

Intermittent episodes of bright light suppress myopia in the chicken more than continuous bright light.

Directory of Open Access Journals (Sweden)

Weizhong Lan

Full Text Available PURPOSE: Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. METHODS: Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8 was kept under office-like illuminance (500 lux at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5, 2 hours (n = 5, 5 hours (n = 4 or 10 hours (n = 4. Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7, 30 minutes (n = 8, 15 minutes (n = 6, 7 minutes (n = 7 or 1 minute (n = 7 periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA. RESULTS: Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1:1 or 7:7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development. CONCLUSIONS: The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1:1 min provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical studies.

Intermittent episodes of bright light suppress myopia in the chicken more than continuous bright light.

Science.gov (United States)

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2014-01-01

Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows. Paradigm I: exposure to constant bright light for either 1 hour (n = 5), 2 hours (n = 5), 5 hours (n = 4) or 10 hours (n = 4). Paradigm II: exposure to repeated cycles of bright light with 50% duty cycle and either 60 minutes (n = 7), 30 minutes (n = 8), 15 minutes (n = 6), 7 minutes (n = 7) or 1 minute (n = 7) periods, provided for 10 hours. Refraction and axial length were measured prior to and immediately after the 5-day experiment. Relative changes were analyzed by paired t-tests, and differences among groups were tested by one-way ANOVA. Compared with the reference group, exposure to continuous bright light for 1 or 2 hours every day had no significant protective effect against deprivation myopia. Inhibition of myopia became significant after 5 hours of bright light exposure but extending the duration to 10 hours did not offer an additional benefit. In comparison, repeated cycles of 1:1 or 7:7 minutes of bright light enhanced the protective effect against myopia and could fully suppress its development. The protective effect of bright light depends on the exposure duration and, to the intermittent form, the frequency cycle. Compared to the saturation effect of continuous bright light, low frequency cycles of bright light (1:1 min) provided the strongest inhibition effect. However, our quantitative results probably might not be directly translated into humans, but rather need further amendments in clinical studies.

Evaluation of retro-reflective coating performance by reflectance and perceived relative brightness measurements

International Nuclear Information System (INIS)

Luse, Kaiva; Pausus, Anete; Karitans, Varis; Ozolins, Maris; Tukisa, Madara

2011-01-01

Retro-reflective properties of six types and five different colors or retro-reflective materials were discussed in this paper. Reflectance optical indicatrix of samples was determined and compared to obtained psychophyisical data of perceived brightness of human observer. Microscopic structure of the retro-reflective active regions of RR's was studied. Statistically significant differences in reflectivity and brightness of various types and colors of RR's were found.

Synchronized observations of bright points from the solar photosphere to the corona

Science.gov (United States)

Tavabi, Ehsan

2018-05-01

One of the most important features in the solar atmosphere is the magnetic network and its relationship to the transition region (TR) and coronal brightness. It is important to understand how energy is transported into the corona and how it travels along the magnetic field lines between the deep photosphere and chromosphere through the TR and corona. An excellent proxy for transportation is the Interface Region Imaging Spectrograph (IRIS) raster scans and imaging observations in near-ultraviolet (NUV) and far-ultraviolet (FUV) emission channels, which have high time, spectral and spatial resolutions. In this study, we focus on the quiet Sun as observed with IRIS. The data with a high signal-to-noise ratio in the Si IV, C II and Mg II k lines and with strong emission intensities show a high correlation with TR bright network points. The results of the IRIS intensity maps and dopplergrams are compared with those of the Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) instruments onboard the Solar Dynamical Observatory (SDO). The average network intensity profiles show a strong correlation with AIA coronal channels. Furthermore, we applied simultaneous observations of the magnetic network from HMI and found a strong relationship between the network bright points in all levels of the solar atmosphere. These features in the network elements exhibited regions of high Doppler velocity and strong magnetic signatures. Plenty of corona bright points emission, accompanied by the magnetic origins in the photosphere, suggest that magnetic field concentrations in the network rosettes could help to couple the inner and outer solar atmosphere.

A selective deficit in the appreciation and recognition of brightness: brightness agnosia?

NARCIS (Netherlands)

Nijboer, T.C.W.; Nys, G.M.S.; van der Smagt, M.J.; de Haan, E.H.F.

2009-01-01

We report a patient with extensive brain damage in the right hemisphere who demonstrated a severe impairment in the appreciation of brightness. Acuity, contrast sensitivity as well as luminance discrimination were normal, suggesting her brightness impairment is not a mere consequence of low-level

The role of the second zero-dispersion wavelength in generation of supercontinua and brigth-bright soliton-pairs across the zero-dispersion wavelength

DEFF Research Database (Denmark)

Frosz, Michael Henoch; Falk, Peter Andreas; Bang, Ole

2005-01-01

Supercontinuum generation with femtosecond pulses in photonic crystal fibers with two zero-dispersion wavelengths (ZDWs) is investigated numerically. The role of the higher ZDW is examined for 5 fiber designs with a nearly constant lower ZDW. It is found that the resulting spectrum is mainly....... Further, the generation of a bright-bright soliton-pair from an initial single red-shifted soliton is found. The soliton-pair has one color in the anomalous dispersion region and the other color in the normal dispersion region, which has not previously been described for bright-bright soliton-pairs....

High-brightness rf linear accelerators

International Nuclear Information System (INIS)

Jameson, R.A.

1986-01-01

The issue of high brightness and its ramifications in linacs driven by radio-frequency fields is discussed. A history of the RF linacs is reviewed briefly. Some current applications are then examined that are driving progress in RF linacs. The physics affecting the brightness of RF linacs is then discussed, followed by the economic feasibility of higher brightness machines

Evaluation of retro-reflective coating performance by reflectance and perceived relative brightness measurements

Energy Technology Data Exchange (ETDEWEB)

Luse, Kaiva; Pausus, Anete; Karitans, Varis; Ozolins, Maris; Tukisa, Madara, E-mail: kaiva.luse@gmail.com [University of Latvia, Optometry and Vision Science Department, Kengaraga street 8, Riga LV-1063 (Latvia)

2011-06-23

Retro-reflective properties of six types and five different colors or retro-reflective materials were discussed in this paper. Reflectance optical indicatrix of samples was determined and compared to obtained psychophyisical data of perceived brightness of human observer. Microscopic structure of the retro-reflective active regions of RR's was studied. Statistically significant differences in reflectivity and brightness of various types and colors of RR's were found.

Brightness of the photosphere and faculae at the limb based on eclipse observations

Energy Technology Data Exchange (ETDEWEB)

Akimov, L.A.; Belkina, I.L.; Dyatel, N.P.

1982-05-01

The absolute distributions of integral and surface brightness of the photospheric continuum (lambdaroughly-equal5870 A) and in faculae at the very limb are obtained from slitless spectrograms of the total solar eclipse of July 10, 1972. Several possible reasons for the brightness increase toward the limb in the distribution of photospheric surface brightness are discussed. The faculae showed high contrasts, up to 1.76 at a height of 200 km from the limb. A comparison of the times of local contacts observed and calculated with allowance for lunar relief showed that the active regions are at about 300 km above the photosphere. A schematic model of a facula is proposed.

Optical and millimeter wavelength study of the complex Sh2-147/Sh2-153

International Nuclear Information System (INIS)

Heydari-Malayeri, M.; Testor, G.; Kahane, C.; Lucas, R.

1982-01-01

Sh2-147/Sh2-153 is a vast HII region-molecular cloud complex of dimension 1 0 .5 located in the Perseus arm at l approximately 109 0 . This cloud embodies the HII regions Sh2-147, 148, 149, 152 and 153. In this direction were detected several H 2 O and OH masers, a number of infrared sources, and a supernova remnant. The authors present the 13 CO map and also optical results on two of the HII regions: Sh2-152 and 148. (Auth.)

A simple approach to spectrally resolved fluorescence and bright field microscopy over select regions of interest.

Science.gov (United States)

Dahlberg, Peter D; Boughter, Christopher T; Faruk, Nabil F; Hong, Lu; Koh, Young Hoon; Reyer, Matthew A; Shaiber, Alon; Sherani, Aiman; Zhang, Jiacheng; Jureller, Justin E; Hammond, Adam T

2016-11-01

A standard wide field inverted microscope was converted to a spatially selective spectrally resolved microscope through the addition of a polarizing beam splitter, a pair of polarizers, an amplitude-mode liquid crystal-spatial light modulator, and a USB spectrometer. The instrument is capable of simultaneously imaging and acquiring spectra over user defined regions of interest. The microscope can also be operated in a bright-field mode to acquire absorption spectra of micron scale objects. The utility of the instrument is demonstrated on three different samples. First, the instrument is used to resolve three differently labeled fluorescent beads in vitro. Second, the instrument is used to recover time dependent bleaching dynamics that have distinct spectral changes in the cyanobacteria, Synechococcus leopoliensis UTEX 625. Lastly, the technique is used to acquire the absorption spectra of CH 3 NH 3 PbBr 3 perovskites and measure differences between nanocrystal films and micron scale crystals.

A simple approach to spectrally resolved fluorescence and bright field microscopy over select regions of interest

Science.gov (United States)

Dahlberg, Peter D.; Boughter, Christopher T.; Faruk, Nabil F.; Hong, Lu; Koh, Young Hoon; Reyer, Matthew A.; Shaiber, Alon; Sherani, Aiman; Zhang, Jiacheng; Jureller, Justin E.; Hammond, Adam T.

2016-11-01

A standard wide field inverted microscope was converted to a spatially selective spectrally resolved microscope through the addition of a polarizing beam splitter, a pair of polarizers, an amplitude-mode liquid crystal-spatial light modulator, and a USB spectrometer. The instrument is capable of simultaneously imaging and acquiring spectra over user defined regions of interest. The microscope can also be operated in a bright-field mode to acquire absorption spectra of micron scale objects. The utility of the instrument is demonstrated on three different samples. First, the instrument is used to resolve three differently labeled fluorescent beads in vitro. Second, the instrument is used to recover time dependent bleaching dynamics that have distinct spectral changes in the cyanobacteria, Synechococcus leopoliensis UTEX 625. Lastly, the technique is used to acquire the absorption spectra of CH3NH3PbBr3 perovskites and measure differences between nanocrystal films and micron scale crystals.

Distribution of surface brightness in Seyfert galaxies. III. Analysis of data

International Nuclear Information System (INIS)

Afanas'ev, V.L.; Doroshenko, V.T.; Terebizh, V.Yu.

1987-01-01

The observational data on the distribution of the surface brightness μ(r) in normal and Seyfert galaxies given in the first two parts of the study [1,2] are considered. The general form of μ(r) for r ≤ approximately equals 2 kpc is the same for the two groups of galaxies. The values of the parameters that characterize the central part of the spherical component are found, namely, the surface brightness μ 1 /sup (0)/, the brightness, the brightness gradient n 1 , and the color indices (U-B) 1 /sup (0)/ and (B-V) 1 /sup (0)/ at distance 1 kpc from the center. The range of variation of the basic parameters and the correlations of the parameters with each other and with the absolute magnitudes M/sub B//sup (0)/ of the galaxies find a natural explanation in the framework of the standard models of the spherical subsystems of galaxies. The relationships have approximately the same form for normal and Seyfert galaxies. The photometric characteristics of the central regions of Sy 1 and Sy 2 type galaxies are similar. The obtained results do not contradict the idea that all sufficiently bright spiral galaxies can pass through a Seyfert stage with a characteristic time of ∼10 8 yr

Do Low Surface Brightness Galaxies Host Stellar Bars?

International Nuclear Information System (INIS)

Cervantes Sodi, Bernardo; Sánchez García, Osbaldo

2017-01-01

With the aim of assessing if low surface brightness galaxies host stellar bars and by studying the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 data set to construct a large volume-limited sample of galaxies and then segregate these galaxies as having low or high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than that found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mostly driven by a correlation of the surface brightness with the spin and the gas richness of the galaxies, showing only a minor dependence on the surface brightness. We also find that the length of the bars is strongly dependent on the surface brightness, and although some of this dependence is attributed to the gas content, even at a fixed gas-to-stellar mass ratio, high surface brightness galaxies host longer bars than their low surface brightness counterparts, which we attribute to an anticorrelation of the surface brightness with the spin.

Do Low Surface Brightness Galaxies Host Stellar Bars?

Energy Technology Data Exchange (ETDEWEB)

Cervantes Sodi, Bernardo; Sánchez García, Osbaldo, E-mail: b.cervantes@irya.unam.mx, E-mail: o.sanchez@irya.unam.mx [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, Campus Morelia, A.P. 3-72, C.P. 58089 Michoacán, México (Mexico)

2017-09-20

With the aim of assessing if low surface brightness galaxies host stellar bars and by studying the dependence of the occurrence of bars as a function of surface brightness, we use the Galaxy Zoo 2 data set to construct a large volume-limited sample of galaxies and then segregate these galaxies as having low or high surface brightness in terms of their central surface brightness. We find that the fraction of low surface brightness galaxies hosting strong bars is systematically lower than that found for high surface brightness galaxies. The dependence of the bar fraction on the central surface brightness is mostly driven by a correlation of the surface brightness with the spin and the gas richness of the galaxies, showing only a minor dependence on the surface brightness. We also find that the length of the bars is strongly dependent on the surface brightness, and although some of this dependence is attributed to the gas content, even at a fixed gas-to-stellar mass ratio, high surface brightness galaxies host longer bars than their low surface brightness counterparts, which we attribute to an anticorrelation of the surface brightness with the spin.

Production of Elephant Trunks in HII Regions by Radiation-Magnetohydrodynamic Instabilities

OpenAIRE

Fierlinger, Katharina; Krumholz, Mark; Grittschneder, Matthias

2010-01-01

Recent SPH and grid code simulations showed, that ionizing radiation can amplify overdensities in turbulent molecular clouds and produce molecular pillars. The relevance of magnetic fields for the structure and stability of molecular clouds is still under discussion. We investigate whether an ionization front hitting a medium with small distortions of the magnetic field can produce the observed pillar-like structures in star forming regions (e.g. Eagle Nebula). Numerical MHD simulations with ...

Dynamics of annular bright field imaging in scanning transmission electron microscopy

International Nuclear Information System (INIS)

Findlay, S.D.; Shibata, N.; Sawada, H.; Okunishi, E.; Kondo, Y.; Ikuhara, Y.

2010-01-01

We explore the dynamics of image formation in the so-called annular bright field mode in scanning transmission electron microscopy, whereby an annular detector is used with detector collection range lying within the cone of illumination, i.e. the bright field region. We show that this imaging mode allows us to reliably image both light and heavy columns over a range of thickness and defocus values, and we explain the contrast mechanisms involved. The role of probe and detector aperture sizes is considered, as is the sensitivity of the method to intercolumn spacing and local disorder.

Proxy magnetometry of the photosphere: why are G-band bright points so bright?

NARCIS (Netherlands)

Rutten, R.J.; Kiselman, Dan; Voort, Luc Rouppe van der; Plez, Bertrand

2000-01-01

We discuss the formation of G-band bright points in terms of standard uxtube modeling, in particular the 1D LTE models constructed by Solanki and coworkers. Combined with LTE spectral synthesis they explain observed G-band bright point contrasts quite well. The G-band contrast increase over the

Source brightness fluctuation correction of solar absorption fourier transform mid infrared spectra

Directory of Open Access Journals (Sweden)

T. Ridder

2011-06-01

Full Text Available The precision and accuracy of trace gas observations using solar absorption Fourier Transform infrared spectrometry depend on the stability of the light source. Fluctuations in the source brightness, however, cannot always be avoided. Current correction schemes, which calculate a corrected interferogram as the ratio of the raw DC interferogram and a smoothed DC interferogram, are applicable only to near infrared measurements. Spectra in the mid infrared spectral region below 2000 cm⁻¹ are generally considered uncorrectable, if they are measured with a MCT detector. Such measurements introduce an unknown offset to MCT interferograms, which prevents the established source brightness fluctuation correction. This problem can be overcome by a determination of the offset using the modulation efficiency of the instrument. With known modulation efficiency the offset can be calculated, and the source brightness correction can be performed on the basis of offset-corrected interferograms. We present a source brightness fluctuation correction method which performs the smoothing of the raw DC interferogram in the interferogram domain by an application of a running mean instead of high-pass filtering the corresponding spectrum after Fourier transformation of the raw DC interferogram. This smoothing can be performed with the onboard software of commercial instruments. The improvement of MCT spectra and subsequent ozone profile and total column retrievals is demonstrated. Application to InSb interferograms in the near infrared spectral region proves the equivalence with the established correction scheme.

Intermittent Episodes of Bright Light Suppress Myopia in the Chicken More than Continuous Bright Light

OpenAIRE

Lan, Weizhong; Feldkaemper, Marita; Schaeffel, Frank

2014-01-01

PURPOSE: Bright light has been shown a powerful inhibitor of myopia development in animal models. We studied which temporal patterns of bright light are the most potent in suppressing deprivation myopia in chickens. METHODS: Eight-day-old chickens wore diffusers over one eye to induce deprivation myopia. A reference group (n = 8) was kept under office-like illuminance (500 lux) at a 10:14 light:dark cycle. Episodes of bright light (15 000 lux) were super-imposed on this background as follows....

On the Relation Between Facular Bright Points and the Magnetic Field

Science.gov (United States)

Berger, Thomas; Shine, Richard; Tarbell, Theodore; Title, Alan; Scharmer, Goran

1994-12-01

Multi-spectral images of magnetic structures in the solar photosphere are presented. The images were obtained in the summers of 1993 and 1994 at the Swedish Solar Telescope on La Palma using the tunable birefringent Solar Optical Universal Polarimeter (SOUP filter), a 10 Angstroms wide interference filter tuned to 4304 Angstroms in the band head of the CH radical (the Fraunhofer G-band), and a 3 Angstroms wide interference filter centered on the Ca II--K absorption line. Three large format CCD cameras with shuttered exposures on the order of 10 msec and frame rates of up to 7 frames per second were used to create time series of both quiet and active region evolution. The full field--of--view is 60times 80 arcseconds (44times 58 Mm). With the best seeing, structures as small as 0.22 arcseconds (160 km) in diameter are clearly resolved. Post--processing of the images results in rigid coalignment of the image sets to an accuracy comparable to the spatial resolution. Facular bright points with mean diameters of 0.35 arcseconds (250 km) and elongated filaments with lengths on the order of arcseconds (10(3) km) are imaged with contrast values of up to 60 % by the G--band filter. Overlay of these images on contemporal Fe I 6302 Angstroms magnetograms and Ca II K images reveals that the bright points occur, without exception, on sites of magnetic flux through the photosphere. However, instances of concentrated and diffuse magnetic flux and Ca II K emission without associated bright points are common, leading to the conclusion that the presence of magnetic flux is a necessary but not sufficient condition for the occurence of resolvable facular bright points. Comparison of the G--band and continuum images shows a complex relation between structures in the two bandwidths: bright points exceeding 350 km in extent correspond to distinct bright structures in the continuum; smaller bright points show no clear relation to continuum structures. Size and contrast statistical cross

Multiscale assessment of progress of electrification in Indonesia based on brightness level derived from nighttime satellite imagery.

Science.gov (United States)

Ramdani, Fatwa; Setiani, Putri

2017-06-01

Availability of electricity can be used as an indicator to proximate parameters related to human well-being. Overall, the electrification process in Indonesia has been accelerating in the past two decades. Unfortunately, monitoring the country's progress on its effort to provide wider access to electricity poses challenges due to inconsistency of data provided by each national bureau, and limited availability of information. This study attempts to provide a reliable measure by employing nighttime satellite imagery to observe and to map the progress of electrification within a duration of 20 years, from 1993 to 2013. Brightness of 67,021 settlement-size points in 1993, 2003, and 2013 was assessed using data from DMSP/OLS instruments to study the electrification progress in the three service regions (Sumatera, Java-Bali, and East Indonesia) of the country's public electricity company, PLN. Observation of all service areas shows that the increase in brightness, which correspond with higher electricity development and consumption, has positive correlation with both population density (R 2  = 0.70) and urban change (R 2  = 0.79). Moreover, urban change has a stronger correlation with brightness, which is probably due to the high energy consumption in urban area per capita. This study also found that the brightness in Java-Bali region is very dominant, while the brightness in other areas has been lagging during the period of analysis. The slow development of electricity infrastructure, particularly in major parts of East Indonesia region, affects the low economic growth in some areas and formed vicious cycle.

BrightStat.com: free statistics online.

Science.gov (United States)

Stricker, Daniel

2008-10-01

Powerful software for statistical analysis is expensive. Here I present BrightStat, a statistical software running on the Internet which is free of charge. BrightStat's goals, its main capabilities and functionalities are outlined. Three different sample runs, a Friedman test, a chi-square test, and a step-wise multiple regression are presented. The results obtained by BrightStat are compared with results computed by SPSS, one of the global leader in providing statistical software, and VassarStats, a collection of scripts for data analysis running on the Internet. Elementary statistics is an inherent part of academic education and BrightStat is an alternative to commercial products.

Brightness and transparency in the early visual cortex.

Science.gov (United States)

Salmela, Viljami R; Vanni, Simo

2013-06-24

Several psychophysical studies have shown that transparency can have drastic effects on brightness and lightness. However, the neural processes generating these effects have remained unresolved. Several lines of evidence suggest that the early visual cortex is important for brightness perception. While single cell recordings suggest that surface brightness is represented in the primary visual cortex, the results of functional magnetic resonance imaging (fMRI) studies have been discrepant. In addition, the location of the neural representation of transparency is not yet known. We investigated whether the fMRI responses in areas V1, V2, and V3 correlate with brightness and transparency. To dissociate the blood oxygen level-dependent (BOLD) response to brightness from the response to local border contrast and mean luminance, we used variants of White's brightness illusion, both opaque and transparent, in which luminance increments and decrements cancel each other out. The stimuli consisted of a target surface and a surround. The surround luminance was always sinusoidally modulated at 0.5 Hz to induce brightness modulation to the target. The target luminance was constant or modulated in counterphase to null brightness modulation. The mean signal changes were calculated from the voxels in V1, V2, and V3 corresponding to the retinotopic location of the target surface. The BOLD responses were significantly stronger for modulating brightness than for stimuli with constant brightness. In addition, the responses were stronger for transparent than for opaque stimuli, but there was more individual variation. No interaction between brightness and transparency was found. The results show that the early visual areas V1-V3 are sensitive to surface brightness and transparency and suggest that brightness and transparency are represented separately.

Increasing the Brightness of Light Sources

OpenAIRE

Fu, Ling

2006-01-01

In modern illumination systems, compact size and high brightness are important features. Light recycling allows an increase of the spectral radiance (brightness) emitted by a light source for the price of reducing the total radiant power. Light recycling means returning part of the emitted light to the source where part of it will escape absorption. As a result, the output brightness can be increased in a restricted phase space, ...

Where are the massive stars of the bar of NGC 1530 forming?

NARCIS (Netherlands)

Zurita, A.

2008-01-01

NGC 1530 has one of the strongest bars ever observed and recent star formation sites are distributed across its bar. Our aim is to study the photometric properties of the bar and its Hii regions, to elucidate the conditions under which Hii regions form and their spatial relation to the principal

H-II Transfer Vehicle (HTV) and the Operations Concept for Extravehicular Activity (EVA) Hardware

Science.gov (United States)

Chullen, Cinda; Blome, Elizabeth; Tetsuya, Sakashita

2011-01-01

With the retirement of the Space Shuttle fleet imminent in 2011, a new operations concept will become reality to meet the transportation challenges of the International Space Station (ISS). The planning associated with the retirement of the Space Shuttle has been underway since the announcement in 2004. Since then, several companies and government entities have had to look for innovative low-cost commercial orbital transportation systems to continue to achieve the objectives of ISS delivery requirements. Several options have been assessed and appear ready to meet the large and demanding delivery requirements of the ISS. Options that have been identified that can facilitate the challenge include the Russian Federal Space Agency's Soyuz and Progress spacecraft, European Space Agency's Automated Transfer Vehicle (ATV), and the Japan Aerospace Exploration Agency's (JAXA s) H-II Transfer Vehicle (HTV). The newest of these options is the JAXA's HTV. This paper focuses on the HTV, mission architecture and operations concept for Extra-Vehicular Activities (EVA) hardware, the associated launch system, and details of the launch operations approach.

Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy

Science.gov (United States)

Weilbacher, Peter M.; Monreal-Ibero, Ana; Verhamme, Anne; Sandin, Christer; Steinmetz, Matthias; Kollatschny, Wolfram; Krajnović, Davor; Kamann, Sebastian; Roth, Martin M.; Erroz-Ferrer, Santiago; Marino, Raffaella Anna; Maseda, Michael V.; Wendt, Martin; Bacon, Roland; Dreizler, Stefan; Richard, Johan; Wisotzki, Lutz

2018-04-01

The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae. FITS images and Table of HII regions are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A95 and at http://muse-vlt.eu/science/antennae/

B and R CCD surface photometry of selected low surface brightness galaxies in the region of the Fornax cluster

International Nuclear Information System (INIS)

Davies, J.I.; Phillipps, S.; Disney, M.J.

1990-01-01

The recent discoveries of large numbers of low surface brightness (LSB) galaxies in clusters and of the extreme LSB giant galaxy Malin 1 are changing our view of the galactic contents of the Universe. In this paper we describe B and R band CCD photometry of a sample of LSB galaxies previously identified from photographic plates of the Fornax cluster. This sample contains some of the lowest surface brightness galaxies known, one having the same central surface brightness as Main 1. The objects in this sample have a wide range of morphologies, and galaxies of similar appearance may have very different (B-R) colours. The range of (B-R) colours for this sample (almost all of which would have been described as dE from their B band morphology alone) is as large as that of the entire Hubble sequence. (author)

ISO spectroscopy of compact HII regions in the Galaxy - II. Ionization and elemental abundances

NARCIS (Netherlands)

Martin-Hernandez, NL; Peeters, E; Morisset, C; Tielens, AGGM; Cox, P; Roelfsema, PR; Baluteau, JP; Schaerer, D; Mathis, JS; Damour, F; Churchwell, E; Kessler, MF

Based on the ISO spectral catalogue of compact H II regions by Peeters et al. (2002), we present a first analysis of the hydrogen recombination and atomic fine-structure lines originated in the ionized gas. The sample consists of 34 H II regions located at galactocentric distances between R-Gal = 0

Does low surface brightness mean low density?

NARCIS (Netherlands)

deBlok, WJG; McGaugh, SS

1996-01-01

We compare the dynamical properties of two galaxies at identical positions on the Tully-Fisher relation, but with different surface brightnesses. We find that the low surface brightness galaxy UGC 128 has a higher mass-to-light ratio, and yet has lower mass densities than the high surface brightness

Time-resolved brightness measurements by streaking

Science.gov (United States)

Torrance, Joshua S.; Speirs, Rory W.; McCulloch, Andrew J.; Scholten, Robert E.

2018-03-01

Brightness is a key figure of merit for charged particle beams, and time-resolved brightness measurements can elucidate the processes involved in beam creation and manipulation. Here we report on a simple, robust, and widely applicable method for the measurement of beam brightness with temporal resolution by streaking one-dimensional pepperpots, and demonstrate the technique to characterize electron bunches produced from a cold-atom electron source. We demonstrate brightness measurements with 145 ps temporal resolution and a minimum resolvable emittance of 40 nm rad. This technique provides an efficient method of exploring source parameters and will prove useful for examining the efficacy of techniques to counter space-charge expansion, a critical hurdle to achieving single-shot imaging of atomic scale targets.

Bright soil units on Mars determined from ISM imaging spectrometer data

Science.gov (United States)

Murchie, Scott; Mustard, John

1993-01-01

The lithology of bright Martian soil provides evidence for chemical and physical processes that have modified the planet's surface. Data from the ISM imaging spectrometer, which observed much of the equatorial region at a spatial resolution of approximately 22 km, cover the NIR wavelength range critical to ascertaining the presence and abundance of Fe-containing phases, hydroxylated silicates, and H2O in the bright soil. ISM data previously have revealed spatial variations in depth of the 3.0-microns H2O absorption suggesting differences in water content, a weak absorption at 2.2 microns indicative of metal-OH in phyllosilicate, and variations in the 1-micron Fe absorption indicative of differences in Fe mineralogy. This paper summarizes first results of a systematic investigation of spectral heterogeneity in bright soils observed by ISM. At least seven 'units' with distinctive properties were discriminated. Comparison of their spatial distributions with Viking data shows that they generally correspond with previously recognized morphologic, color, and thermal features. These correspondences and the units' spectral attributes provide evidence for lithologic differences between the soils in different geologic settings.

VizieR Online Data Catalog: Infrared morphology of HII regions (Topchieva+, 2017)

Science.gov (United States)

Topchieva, A. P.; Wiebe, D. S.; Kirsanova, M. S.; Krushinskii, V. V.

2018-03-01

The 20-cm New GPS survey (http://third.ucllnl.org/gps), created using the MAGPIS database of radio images of regions with Galactic coordinates |bGal|MIPS (Rieke et al., 2004ApJS..154...25R) cameras of the Spitzer Telescope. The resulting list contains objects having the appearance of rings at 8um, inside of which IR emission at 24um and radio emission at 20cm is observed. (2 data files).

The Oxygen and Nitrogen Abundance of Leo A and GR 8

Science.gov (United States)

van Zee, L.; Skillman, E. D.; Haynes, M. P.

1999-05-01

Gas phase abundances are one of the best measures of the intrinsic metallicity of low mass galaxies. We recently obtained low resolution long slit optical spectra of several HII regions in Leo A and GR 8 with the Palomar 5m telescope. Previous studies of the resolved stellar population of Leo A indicated that the stars have metallicities approximately 2% of solar (Tolstoy et al. 1998). Preliminary analysis of the HII region spectra, and that of a planetary nebula, indicates that the gas phase oxygen abundance of Leo A is approximately 3% of solar. This confirms the result of Skillman et al. (1989), who also derived an oxygen abundance for Leo A from a planetary nebula. Similarly, for GR 8 we find a mean oxygen abundance of 5% of solar. For all the HII regions, the derived log(N/O) is -1.5 +/- 0.1, as has been found for other low metallicity systems. These new observations of multiple HII regions in Leo A and GR 8 confirm that metals in low mass galaxies are well mixed.

NIGHT SKY BRIGHTNESS ABOVE ZAGREB 2012.-2017.

Directory of Open Access Journals (Sweden)

Željko Andreić

2018-01-01

Full Text Available The night sky brightness at the RGN site (near the centre of Zagreb, Croatia was monitored form January 2012. to December 2017. The gathered data show that the average night sky brightness in this period did not change significantly, apart from differences caused by yearly variations in meteorological parameters. The nightly minima, maxima and mean values of the sky brightness do change considerably due to changes in meteorological conditions, often being between 2 and 3 magnitudes. The seasonal probability curves and histograms are constructed and are used to obtain additional information on the light pollution at the RGN site. They reveal that the night sky brightness clutters around two peaks, at about 15.0 mag/arcsec2 and at about 18.2 mag/arcsec2. The tendency to slightly lower brightness values in spring and summer can also be seen in the data. Two peaks correspond to cloudy and clear nights respectively, the difference in brightness between them being about 3 magnitudes. A crude clear/cloudy criterion can be defined too: the minimum between two peaks is around 16.7 mag/arcsec2. The brightness values smaller than thisare attributed to clear nights and vice-versa. Comparison with Vienna and Hong-Kong indicates that the light pollution of Zagreb is a few times larger.

Electron beam brightness with field immersed emission

International Nuclear Information System (INIS)

Boyd, J.K.; Neil, V.K.

1985-01-01

The beam quality or brightness of an electron beam produced with field immersed emission is studied with two models. First, an envelope formulation is used to determine the scaling of brightness with current, magnetic field and cathode radius, and examine the equilibrium beam radius. Second, the DPC computer code is used to calculate the brightness of two electron beam sources

Teradiode's high brightness semiconductor lasers

Science.gov (United States)

Huang, Robin K.; Chann, Bien; Burgess, James; Lochman, Bryan; Zhou, Wang; Cruz, Mike; Cook, Rob; Dugmore, Dan; Shattuck, Jeff; Tayebati, Parviz

2016-03-01

TeraDiode is manufacturing multi-kW-class ultra-high brightness fiber-coupled direct diode lasers for industrial applications. A fiber-coupled direct diode laser with a power level of 4,680 W from a 100 μm core diameter, BPP) of 3.5 mm-mrad and is the lowest BPP multi-kW-class direct diode laser yet reported. This laser is suitable for industrial materials processing applications, including sheet metal cutting and welding. This 4-kW fiber-coupled direct diode laser has comparable brightness to that of industrial fiber lasers and CO2 lasers, and is over 10x brighter than state-of-the-art direct diode lasers. We have also demonstrated novel high peak power lasers and high brightness Mid-Infrared Lasers.

143 GHz BRIGHTNESS MEASUREMENTS OF URANUS, NEPTUNE, AND OTHER SECONDARY CALIBRATORS WITH BOLOCAM BETWEEN 2003 AND 2010

International Nuclear Information System (INIS)

Sayers, J.; Czakon, N. G.; Golwala, S. R.

2012-01-01

Bolocam began collecting science data in 2003 as the long-wavelength imaging camera at the Caltech Submillimeter Observatory. The planets, along with a handful of secondary calibrators, have been used to determine the flux calibration for all of the data collected with Bolocam. Uranus and Neptune stand out as the only two planets that are bright enough to be seen with high signal-to-noise in short integrations without saturating the standard Bolocam readout electronics. By analyzing all of the 143 GHz observations made with Bolocam between 2003 and 2010, we find that the brightness ratio of Uranus to Neptune is 1.027 ± 0.006, with no evidence for any variations over that period. Including previously published results at ≅ 150 GHz, we find a brightness ratio of 1.029 ± 0.006 with no evidence for time variability over the period 1983-2010. Additionally, we find no evidence for time variability in the brightness ratio of either Uranus or Neptune to the ultracompact H II region G34.3 or the protostellar source NGC 2071IR. Using recently published Wilkinson Microwave Anisotropy Probe results we constrain the absolute 143 GHz brightness of both Uranus and Neptune to ≅ 3%. Finally, we present ≅ 3% absolute 143 GHz peak flux density values for the ultracompact H II regions G34.3 and K3-50A and the protostellar source NGC 2071IR.

Very bright optical transient near the Trifid and Lagoon Nebulae

Science.gov (United States)

Dunsby, Peter

2018-03-01

Peter Dunsby (University of Cape Town) reports the detection of a very bright optical transient in the region between the Lagoon and Trifid Nebulae based on observations obtained from Cape Town on 20 March 2018, between 01:00 and 03:45 UT. The object was visible throughout the full duration of the observations and not seen when this field was observed previously (08 March 2018).

Unveiling the Low Surface Brightness Stellar Peripheries of Galaxies

Science.gov (United States)

Ferguson, Annette M. N.

2018-01-01

The low surface brightness peripheral regions of galaxies contain a gold mine of information about how minor mergers and accretions have influenced their evolution over cosmic time. Enormous stellar envelopes and copious amounts of faint tidal debris are natural outcomes of the hierarchical assembly process and the search for and study of these features, albeit highly challenging, offers the potential for unrivalled insight into the mechanisms of galaxy growth. Over the last two decades, there has been burgeoning interest in probing galaxy outskirts using resolved stellar populations. Wide-field surveys have uncovered vast tidal debris features and new populations of very remote globular clusters, while deep Hubble Space Telescope photometry has provided exquisite star formation histories back to the earliest epochs. I will highlight some recent results from studies within and beyond the Local Group and conclude by briefly discussing the great potential of future facilities, such as JWST, Euclid, LSST and WFIRST, for major breakthroughs in low surface brightness galaxy periphery science.

Study of Three-Dimensional Image Brightness Loss in Stereoscopy

Directory of Open Access Journals (Sweden)

Hsing-Cheng Yu

2015-10-01

Full Text Available When viewing three-dimensional (3D images, whether in cinemas or on stereoscopic televisions, viewers experience the same problem of image brightness loss. This study aims to investigate image brightness loss in 3D displays, with the primary aim being to quantify the image brightness degradation in the 3D mode. A further aim is to determine the image brightness relationship to the corresponding two-dimensional (2D images in order to adjust the 3D-image brightness values. In addition, the photographic principle is used in this study to measure metering values by capturing 2D and 3D images on television screens. By analyzing these images with statistical product and service solutions (SPSS software, the image brightness values can be estimated using the statistical regression model, which can also indicate the impact of various environmental factors or hardware on the image brightness. In analysis of the experimental results, comparison of the image brightness between 2D and 3D images indicates 60.8% degradation in the 3D image brightness amplitude. The experimental values, from 52.4% to 69.2%, are within the 95% confidence interval

The lowest surface brightness disc galaxy known

International Nuclear Information System (INIS)

Davies, J.I.; Phillipps, S.; Disney, M.J.

1988-01-01

The discovery of a galaxy with a prominent bulge and a dominant extremely low surface brightness disc component is reported. The profile of this galaxy is very similar to the recently discovered giant low surface brightness galaxy Malin 1. The disc central surface brightness is found to be ∼ 26.4 Rμ, some 1.5 mag fainter than Malin 1 and thus by far the lowest yet observed. (author)

Brightness masking is modulated by disparity structure.

Science.gov (United States)

Pelekanos, Vassilis; Ban, Hiroshi; Welchman, Andrew E

2015-05-01

The luminance contrast at the borders of a surface strongly influences surface's apparent brightness, as demonstrated by a number of classic visual illusions. Such phenomena are compatible with a propagation mechanism believed to spread contrast information from borders to the interior. This process is disrupted by masking, where the perceived brightness of a target is reduced by the brief presentation of a mask (Paradiso & Nakayama, 1991), but the exact visual stage that this happens remains unclear. In the present study, we examined whether brightness masking occurs at a monocular-, or a binocular-level of the visual hierarchy. We used backward masking, whereby a briefly presented target stimulus is disrupted by a mask coming soon afterwards, to show that brightness masking is affected by binocular stages of the visual processing. We manipulated the 3-D configurations (slant direction) of the target and mask and measured the differential disruption that masking causes on brightness estimation. We found that the masking effect was weaker when stimuli had a different slant. We suggest that brightness masking is partly mediated by mid-level neuronal mechanisms, at a stage where binocular disparity edge structure has been extracted. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Brightness and darkness as perceptual dimensions

NARCIS (Netherlands)

Vladusich, T.; Lucassen, M.P.; Cornelissen, F.W.

2007-01-01

A common-sense assumption concerning visual perception states that brightness and darkness cannot coexist at a given spatial location. One corollary of this assumption is that achromatic colors, or perceived grey shades, are contained in a one-dimensional (1-D) space varying from bright to dark. The

Brightness/darkness induction and the genesis of a contour

Directory of Open Access Journals (Sweden)

Sergio eRoncato

2014-10-01

Full Text Available Visual contours often result from the integration or interpolation of fragmented edges.The strength of the completion increases when the edges share the same contrast polarity (CP. Here we demonstrate that the appearance in the perceptual field of this integrated unit, or contour of invariant CP, is concomitant with a vivid brightness alteration of the surfaces at its opposite sides. To observe this effect requires some stratagems because the formation in the visual field of a contour of invariant CP normally engenders the formation of a second contour and then the rise of two streams of induction signals that interfere in different ways. Particular configurations have been introduced that allow us to observe the induction effects of one contour taken in isolation. I documented these effects by phenomenological observations and psychophysical measurement of the brightness alteration in relation to luminance contrast. When the edges of the same CP complete to form a contour, the background of homogeneous luminance appears to dim at one side and to brighten at the opposite side (in accord with the CP. The strength of the phenomenon is proportional to the local luminance contrast. This effect weakens or nulls when the contour of the invariant CP separates surfaces filled with different grey shades.These conflicting results stimulate a deeper exploration of the induction phenomena and their role in the computation of brightness contrast. An alternative perspective is offered to account for some brightness illusions and their relation to the phenomenal transparency. The main assumption asserts that, when in the same region induction signals of opposite CP overlap, the filling-in are blocked unless the image is stratified into different layers, one for each signal of the same polarity. Phenomenological observations document this solution by the visual system

Effect of evening exposure to bright or dim light after daytime bright light on absorption of dietary carbohydrates the following morning.

Science.gov (United States)

Hirota, Naoko; Sone, Yoshiaki; Tokura, Hiromi

2010-01-01

We had previously reported on the effect of exposure to light on the human digestive system: daytime bright light exposure has a positive effect, whereas, evening bright light exposure has a negative effect on the efficiency of dietary carbohydrate absorption from the evening meal. These results prompted us to examine whether the light intensity to which subjects are exposed in the evening affects the efficiency of dietary carbohydrate absorption the following morning. In this study, subjects were exposed to either 50 lux (dim light conditions) or 2,000 lux (bright light conditions) in the evening for 9 h (from 15:00 to 24:00) after staying under bright light in the daytime (under 2,000 lux from 07:00 to 15:00). We measured unabsorbed dietary carbohydrates using the breath-hydrogen test the morning after exposure to either bright light or dim light the previous evening. Results showed that there was no significant difference between the two conditions in the amount of breath hydrogen. This indicates that evening exposure to bright or dim light after bright light exposure in the daytime has no varying effect on digestion or absorption of dietary carbohydrates in the following morning's breakfast.

Unperturbed moderator brightness in pulsed neutron sources

International Nuclear Information System (INIS)

Batkov, K.; Takibayev, A.; Zanini, L.; Mezei, F.

2013-01-01

The unperturbed neutron brightness of a moderator can be defined from the number of neutrons leaving the surface of a moderator completely surrounded by a reflector. Without openings for beam extraction, it is the maximum brightness that can be theoretically achieved in a moderator. The unperturbed brightness of a cylindrical cold moderator filled with pure para-H 2 was calculated using MCNPX; the moderator dimensions were optimised, for a fixed target and reflector geometry corresponding to the present concept for the ESS spallation source. This quantity does not depend on openings for beam extraction and therefore can be used for a first-round optimisation of a moderator, before effects due to beam openings are considered. We find that such an optimisation yields to a factor of 2 increase with respect to a conventional volume moderator, large enough to accommodate a viewed surface of 12×12 cm 2 : the unperturbed neutron brightness is maximum for a disc-shaped moderator of 15 cm diameter, 1.4 cm height. The reasons for this increase can be related to the properties of the scattering cross-section of para-H 2 , to the added reflector around the exit surface in the case of a compact moderator, and to a directionality effect. This large optimisation gain in the unperturbed brightness hints towards similar potentials for the perturbed neutron brightness, in particular in conjunction with advancing the optical quality of neutron delivery from the moderator to the sample, where by Liouville theorem the brightness is conserved over the beam trajectory, except for absorption and similar type losses

Dynamics of Subarcsecond Bright Dots in the Transition Region above Sunspots and Their Relation to Penumbral Micro-jets

Energy Technology Data Exchange (ETDEWEB)

Samanta, Tanmoy; Banerjee, Dipankar [Indian Institute of Astrophysics, Koramangala, Bangalore 560034 (India); Tian, Hui [School of Earth and Space Sciences, Peking University (China); Schanche, Nicole, E-mail: tsamanta@iiap.res.in, E-mail: huitian@pku.edu.cn, E-mail: dipu@iiap.res.in, E-mail: ns81@st-andrews.ac.uk [University of St. Andrews, St. Andrews (United Kingdom)

2017-02-01

Recent high-resolution observations have revealed that subarcsecond bright dots (BDs) with sub-minute lifetimes appear ubiquitously in the transition region (TR) above sunspot penumbra. The presence of penumbral micro-jets (PMJs) in the chromosphere was previously reported. It was proposed that both the PMJs and BDs are formed due to a magnetic reconnection process and may play an important role in heating of the penumbra. Using simultaneous observations of the chromosphere from the Solar Optical Telescope (SOT) on board Hinode and observations of the TR from the Interface Region Imaging Spectrograph , we study the dynamics of BDs and their relation to PMJs. We find two types of BDs, one that is related to PMJs, and another that does not show any visible dynamics in the SOT Ca ii H images. From a statistical analysis we show that these two types have different properties. The BDs that are related to PMJs always appear at the top of the PMJs, the vast majority of which show inward motion and originate before the generation of the PMJs. These results may indicate that the reconnection occurs at the lower coronal/TR height and initiates PMJs at the chromosphere. This formation mechanism is in contrast with the formation of PMJs by reconnection in the (upper) photosphere between differently inclined fields.

The Variability of Atmospheric Deuterium Brightness at Mars: Evidence for Seasonal Dependence

Science.gov (United States)

Mayyasi, Majd; Clarke, John; Bhattacharyya, Dolon; Deighan, Justin; Jain, Sonal; Chaffin, Michael; Thiemann, Edward; Schneider, Nick; Jakosky, Bruce

2017-10-01

The enhanced ratio of deuterium to hydrogen on Mars has been widely interpreted as indicating the loss of a large column of water into space, and the hydrogen content of the upper atmosphere is now known to be highly variable. The variation in the properties of both deuterium and hydrogen in the upper atmosphere of Mars is indicative of the dynamical processes that produce these species and propagate them to altitudes where they can escape the planet. Understanding the seasonal variability of D is key to understanding the variability of the escape rate of water from Mars. Data from a 15 month observing campaign, made by the Mars Atmosphere and Volatile Evolution Imaging Ultraviolet Spectrograph high-resolution echelle channel, are used to determine the brightness of deuterium as observed at the limb of Mars. The D emission is highly variable, with a peak in brightness just after southern summer solstice. The trends of D brightness are examined against extrinsic as well as intrinsic sources. It is found that the fluctuations in deuterium brightness in the upper atmosphere of Mars (up to 400 km), corrected for periodic solar variations, vary on timescales that are similar to those of water vapor fluctuations lower in the atmosphere (20-80 km). The observed variability in deuterium may be attributed to seasonal factors such as regional dust storm activity and subsequent circulation lower in the atmosphere.

The brightness of colour.

Directory of Open Access Journals (Sweden)

David Corney

Full Text Available The perception of brightness depends on spatial context: the same stimulus can appear light or dark depending on what surrounds it. A less well-known but equally important contextual phenomenon is that the colour of a stimulus can also alter its brightness. Specifically, stimuli that are more saturated (i.e. purer in colour appear brighter than stimuli that are less saturated at the same luminance. Similarly, stimuli that are red or blue appear brighter than equiluminant yellow and green stimuli. This non-linear relationship between stimulus intensity and brightness, called the Helmholtz-Kohlrausch (HK effect, was first described in the nineteenth century but has never been explained. Here, we take advantage of the relative simplicity of this 'illusion' to explain it and contextual effects more generally, by using a simple Bayesian ideal observer model of the human visual ecology. We also use fMRI brain scans to identify the neural correlates of brightness without changing the spatial context of the stimulus, which has complicated the interpretation of related fMRI studies.Rather than modelling human vision directly, we use a Bayesian ideal observer to model human visual ecology. We show that the HK effect is a result of encoding the non-linear statistical relationship between retinal images and natural scenes that would have been experienced by the human visual system in the past. We further show that the complexity of this relationship is due to the response functions of the cone photoreceptors, which themselves are thought to represent an efficient solution to encoding the statistics of images. Finally, we show that the locus of the response to the relationship between images and scenes lies in the primary visual cortex (V1, if not earlier in the visual system, since the brightness of colours (as opposed to their luminance accords with activity in V1 as measured with fMRI.The data suggest that perceptions of brightness represent a robust

Future prospect of the research study using intense and bright synchrotron radiation in VUV and soft x-ray region

International Nuclear Information System (INIS)

Tanaka, Kenichiro; Miyahara, Tsuneaki

1987-02-01

This report is the summary of the contents of the study meeting 'Future prospect of the research study using intense and bright synchrotron radiation in VUV and soft x-ray region' sponsored by PF, held on October 20 and 21, 1986. This study meeting was held by inviting those who are particularly interested in the basic field among the users of VUV and soft x-ray region, and the research on the application field was excluded. The objective of the discussion of this study meeting was to talk about the dream that if a high luminance light source which is 100 - 1000 times more intense in terms of luminous flux intensity is completed, what can we do with it. Three sessions on the themes 'How the existing research fields will develop', 'What the possible new research fields are' and 'Comment from the technical aspect' were held. More than seven years elapsed since the beginning of construction of the Photon Factory. Many excellent results have been obtained. As of October, 1986, the beam lines available for experiment are 11, the themes of common utilization experiment in progress are 300, and the number of registered researchers exceeded 1000. The development of a new light emission source is to be undertaken. (Kako, I.)

Suzaku observations of low surface brightness cluster Abell 1631

Science.gov (United States)

Babazaki, Yasunori; Mitsuishi, Ikuyuki; Ota, Naomi; Sasaki, Shin; Böhringer, Hans; Chon, Gayoung; Pratt, Gabriel W.; Matsumoto, Hironori

2018-06-01

We present analysis results for a nearby galaxy cluster Abell 1631 at z = 0.046 using the X-ray observatory Suzaku. This cluster is categorized as a low X-ray surface brightness cluster. To study the dynamical state of the cluster, we conduct four-pointed Suzaku observations and investigate physical properties of the Mpc-scale hot gas associated with the A 1631 cluster for the first time. Unlike relaxed clusters, the X-ray image shows no strong peak at the center and an irregular morphology. We perform spectral analysis and investigate the radial profiles of the gas temperature, density, and entropy out to approximately 1.5 Mpc in the east, north, west, and south directions by combining with the XMM-Newton data archive. The measured gas density in the central region is relatively low (a few ×10-4 cm-3) at the given temperature (˜2.9 keV) compared with X-ray-selected clusters. The entropy profile and value within the central region (r clusters. These features are also observed in another low surface brightness cluster, Abell 76. The spatial distributions of galaxies and the hot gas appear to be different. The X-ray luminosity is relatively lower than that expected from the velocity dispersion. A post-merger scenario may explain the observed results.

Stellar populations of bulges in galaxies with a low surface-brightness disc

Science.gov (United States)

Morelli, L.; Corsini, E. M.; Pizzella, A.; Dalla Bontà, E.; Coccato, L.; Méndez-Abreu, J.

2015-03-01

The radial profiles of the Hβ, Mg, and Fe line-strength indices are presented for a sample of eight spiral galaxies with a low surface-brightness stellar disc and a bulge. The correlations between the central values of the line-strength indices and velocity dispersion are consistent to those known for early-type galaxies and bulges of high surface-brightness galaxies. The age, metallicity, and α/Fe enhancement of the stellar populations in the bulge-dominated region are obtained using stellar population models with variable element abundance ratios. Almost all the sample bulges are characterized by a young stellar population, on-going star formation, and a solar α/Fe enhancement. Their metallicity spans from high to sub-solar values. No significant gradient in age and α/Fe enhancement is measured, whereas only in a few cases a negative metallicity gradient is found. These properties suggest that a pure dissipative collapse is not able to explain formation of all the sample bulges and that other phenomena, like mergers or acquisition events, need to be invoked. Such a picture is also supported by the lack of a correlation between the central value and gradient of the metallicity in bulges with very low metallicity. The stellar populations of the bulges hosted by low surface-brightness discs share many properties with those of high surface-brightness galaxies. Therefore, they are likely to have common formation scenarios and evolution histories. A strong interplay between bulges and discs is ruled out by the fact that in spite of being hosted by discs with extremely different properties, the bulges of low and high surface-brightness discs are remarkably similar.

The ZTF Bright Transient Survey

Science.gov (United States)

Fremling, C.; Sharma, Y.; Kulkarni, S. R.; Miller, A. A.; Taggart, K.; Perley, D. A.; Gooba, A.

2018-06-01

As a supplement to the Zwicky Transient Facility (ZTF; ATel #11266) public alerts (ATel #11685) we plan to report (following ATel #11615) bright probable supernovae identified in the raw alert stream from the ZTF Northern Sky Survey ("Celestial Cinematography"; see Bellm & Kulkarni, 2017, Nature Astronomy 1, 71) to the Transient Name Server (https://wis-tns.weizmann.ac.il) on a daily basis; the ZTF Bright Transient Survey (BTS; see Kulkarni et al., 2018; arXiv:1710.04223).

The night sky brightness at McDonald Observatory

Science.gov (United States)

Kalinowski, J. K.; Roosen, R. G.; Brandt, J. C.

1975-01-01

Baseline observations of the night sky brightness in B and V are presented for McDonald Observatory. In agreement with earlier work by Elvey and Rudnick (1937) and Elvey (1943), significant night-to-night and same-night variations in sky brightness are found. Possible causes for these variations are discussed. The largest variation in sky brightness found during a single night is approximately a factor of two, a value which corresponds to a factor-of-four variation in airglow brightness. The data are used to comment on the accuracy of previously published surface photometry of M 81.

Dark-Bright Soliton Dynamics Beyond the Mean-Field Approximation

Science.gov (United States)

Katsimiga, Garyfallia; Koutentakis, Georgios; Mistakidis, Simeon; Kevrekidis, Panagiotis; Schmelcher, Peter; Theory Group of Fundamental Processes in Quantum Physics Team

2017-04-01

The dynamics of dark bright solitons beyond the mean-field approximation is investigated. We first examine the case of a single dark-bright soliton and its oscillations within a parabolic trap. Subsequently, we move to the setting of collisions, comparing the mean-field approximation to that involving multiple orbitals in both the dark and the bright component. Fragmentation is present and significantly affects the dynamics, especially in the case of slower solitons and in that of lower atom numbers. It is shown that the presence of fragmentation allows for bipartite entanglement between the distinguishable species. Most importantly the interplay between fragmentation and entanglement leads to the decay of each of the initial mean-field dark-bright solitons into fast and slow fragmented dark-bright structures. A variety of excitations including dark-bright solitons in multiple (concurrently populated) orbitals is observed. Dark-antidark states and domain-wall-bright soliton complexes can also be observed to arise spontaneously in the beyond mean-field dynamics. Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Diagnostics for high-brightness beams

International Nuclear Information System (INIS)

Shafer, R.E.

1990-01-01

Special techniques are required for beam diagnostics on high-brightness particle beams. Examples of high-brightness beams include low-emittance proton linacs (either pulsed or CW), electron linacs suitable for free-electron-laser applications, and future linear colliders. Non-interceptive and minimally-interceptive techniques for measuring beam current, position, profile, and transverse and longitudinal emittance will be reviewed. Included will be stripline, wire scanner, laser neutralization, beam-beam scattering, interceptive microgratings, spontaneous emission, optical transition radiation, and other techniques. 24 refs

IRAS surface brightness maps of reflection nebulae in the Pleiades

Science.gov (United States)

Castelaz, Michael W.; Werner, M. W.; Sellgren, K.

1987-01-01

Surface brightness maps at 12, 25, 60, and 100 microns were made of a 2.5 deg x 2.5 deg area of the reflection nebulae in the Pleiades by coadding IRAS scans of this region. Emission is seen surrounding 17 Tau, 20 Tau, 23 Tau, and 25 Tau in all four bands, coextensive with the visible reflection nebulosity, and extending as far as 30 arcminutes from the illuminating stars. The infrared energy distributions of the nebulae peak in the 100 micron band, but up to 40 percent of the total infrared power lies in the 12 and 25 micron bands. The brightness of the 12 and 25 micron emission and the absence of temperature gradients at these wavelengths are inconsistent with the predictions of equilibrium thermal emission models. The emission at these wavelengths appears to be the result of micron nonequilibrium emission from very small grains, or from molecules consisting of 10-100 carbon atoms, which have been excited by ultraviolet radiation from the illuminating stars.

High brightness semiconductor lasers with reduced filamentation

DEFF Research Database (Denmark)

McInerney, John; O'Brien, Peter.; Skovgaard, Peter M. W.

1999-01-01

High brightness semiconductor lasers have applications in spectroscopy, fiber lasers, manufacturing and materials processing, medicine and free space communication or energy transfer. The main difficulty associated with high brightness is that, because of COD, high power requires a large aperture...

Probing the End of the IMF in NGC 2024 with NIRCam on JWST: Assessing the Impact of Nebular Emission in Galactic Star Forming Regions

Science.gov (United States)

Suri, Veenu; Meyer, Michael; Greenbaum, Alexandra Z.; Bell, Cameron; Beichman, Charles; Gordon, Karl D.; Greene, Thomas P.; Hodapp, K.; Horner, Scott; Johnstone, Doug; Leisenring, Jarron; Manara, Carlos; Mann, Rita; Misselt, K.; Raileanu, Roberta; Rieke, Marcia; Roellig, Thomas

2018-01-01

We describe observations of the embedded young cluster associated with the HII region NGC 2024 planned as part of the guaranteed time observing program for the James Webb Space Telescope with the NIRCam (Near Infrared Camera) instrument. Our goal is to obtain a census of the cluster down to 2 Jupiter masses, viewed through 10-20 magnitudes of extinction, using multi-band filter photometry, both broadband filters and intermediate band filters that are expected to be sensitive to temperature and surface gravity. The cluster contains several bright point sources as well as extended emission due to reflected light, thermal emission from warm dust, as well as nebular line emission. We first developed techniques to better understand which point sources would saturate in our target fields when viewed through several JWST NIRCam filters. Using images of the field with the WISE satellite in filters W1 and W2, as well as 2MASS (J and H) bands, we devised an algorithm that takes the K-band magnitudes of point sources in the field, and the known saturation limits of several NIRCam filters to estimate the impact of the extended emission on survey sensitivity. We provide an overview of our anticipated results, detecting the low mass end of the IMF as well as planetary mass objects likely liberated through dynamical interactions.

CO observations of a molecular cloud complex associated with the bright rim near VY Canis Majoris

International Nuclear Information System (INIS)

Lada, C.J.; Reid, M.J.

1978-01-01

Extensive CO observations of a large molecular cloud complex (approx. 15 pc) associated with a bright rim near the peculiar star VY CMa are presented. CO emission peaks in a region along and adjacent to the bright rim which forms the western border of the cloud complex. This emission abruptly decreases across the bright rim, and this decrease suggests a physical association of the rim with the cloud. The molecular complex is found to consist of two clouds which have different radial velocities and physical properties. The possibility that these two clouds may be in near-collision is discussed. The physical association of the bright rim with the cloud complex indicates that the clouds are at the same distance, 1.5 kpc, as the stars which excite the rim. Since VY CMa appears to be located at the tip of the bright rim and has a velocity similar to that of the molecular cloud complex and the stars of the cluster NGC 2362, it is concluded that VY CMa is also at the same distance. The resulting luminosity of VY CMa (5 x 10 5 L sub solar) indicates that the star is very massive, and places constraints on interpretation of its evolutionary state. 5 figures, 2 tables

VizieR Online Data Catalog: Radio observations of Galactic WISE HII regions (Anderson+, 2015)

Science.gov (United States)

Anderson, L. D.; Armentrout, W. P.; Johnstone, B. M.; Bania, T. M.; Balser, D. S.; Wenger, T. V.; Cunningham, V.

2016-01-01

We draw our targets from the MIR objects in the WISE catalog of Anderson+, 2014, J/ApJS/212/1. We also include in our sample Sharpless H II regions (Sharpless 1959, VII/20). See section 2 for further details. Our observations were made with the GBT 100m telescope from 2012 July through 2014 August. There are seven radio recombination lines (RRLs) that can be cleanly observed simultaneously with the GBT in the X-band: H87α to H93α. We average these seven RRLs (each at two orthogonal polarizations) to create a single average RRL spectrum. We followed the same GBT observational procedure as in the original HRDS (Green Bank Telescope H II Region Discovery Survey (GBT HRDS; Bania et al. 2010ApJ...718L.106B). (3 data files).

Burkina Faso - BRIGHT II

Data.gov (United States)

Millennium Challenge Corporation — Millennium Challenge Corporation hired Mathematica Policy Research to conduct an independent evaluation of the BRIGHT II program. The three main research questions...

Increasing the brightness of light sources

Energy Technology Data Exchange (ETDEWEB)

Fu, Ling

2006-11-16

In this work the principle of light recycling is applied to artificial light sources in order to achieve brightness enhancement. Firstly, the feasibilities of increasing the brightness of light sources via light recycling are examined theoretically, based on the fundamental laws of thermodynamics including Kirchhoff's law on radiation, Planck's law, Lambert-Beer's law, the etendue conservation and the brightness theorem. From an experimental viewpoint, the radiation properties of three different kinds of light sources including short-arc lamps, incandescent lamps and LEDs characterized by their light-generating mechanisms are investigated. These three types of sources are used in light recycling experiments, for the purpose of 1. validating the intrinsic light recycling effect in light sources, e. g. the intrinsic light recycling effect in incandescent lamps stemming from the coiled filament structure. 2. acquiring the required parameters for establishing physical models, e.g. the emissivity/absorptivity of the short-arc lamps, the intrinsic reflectivity and the external quantum efficiency of LEDs. 3. laying the foundations for designing optics aimed at brightness enhancement according to the characteristics of the sources and applications. Based on the fundamental laws and experiments, two physical models for simulating the radiance distribution of light sources are established, one for thermal filament lamps, the other for luminescent sources, LEDs. As validation of the theoretical and experimental investigation of the light recycling effect, an optical device, the Carambola, is designed for achieving deterministic and multiple light recycling. The Carambola has the function of a concentrator. In order to achieve the maximum possible brightness enhancement with the Carambola, several combinations of sources and Carambolas are modelled in ray-tracing simulations. Sources with different light-emitting mechanisms and different radiation properties

Life-threatening motor vehicle crashes in bright sunlight

OpenAIRE

Redelmeier, Donald A.; Raza, Sheharyar

2017-01-01

Abstract Bright sunlight may create visual illusions that lead to driver error, including fallible distance judgment from aerial perspective. We tested whether the risk of a life-threatening motor vehicle crash was increased when driving in bright sunlight. This longitudinal, case-only, paired-comparison analysis evaluated patients hospitalized because of a motor vehicle crash between January 1, 1995 and December 31, 2014. The relative risk of a crash associated with bright sunlight was estim...

Spitzer Observations of M33 & M83 and the Hot Star, Hii Region Connection

Science.gov (United States)

Rubin, R.; Simpson, J.; Colgan, S.; Dufour, R.; Citron, R.; Ray, K.; Erickson, E.; Haas, M.; Pauldrach, A.

2007-05-01

H II regions play a crucial role in the measurement of current interstellar abundances. They also serve as laboratories for atomic physics and provide fundamental data about heavy element abundances that serve to constrain models of galactic chemical evolution. We observed emission lines of [S IV] 10.5, H (7-6) 12.4, [Ne II] 12.8, [Ne III] 15.6, & [S III] 18.7 micron cospatially with the Spitzer Space Telescope using the Infrared Spectrograph (IRS) in short-high mode (SH). Here we concentrate on the galaxy M33 and compare the results with our earlier similar study of M83. In each of these substantially face-on spirals, we observed ˜25 H II regions, covering a full range of galactocentric radii (RG). For most of the M33 H II regions, we were able to measure the H (7-6) line while none were detectable in M83. This limited our M83 study to a determination of the Ne++/Ne+, /, and S3+/S++ abundance ratios vs. RG. Angular brackets denote fractional ionizations. As well as having the addition of fluxes for the H(7-6) line, the M33 H II regions are generally of much higher ionization than those in M83, resulting in larger Ne++/Ne+ and S3+/ S++ abundance ratios. For M33, in addition to what we derived for those nebulae in M83, we are also able to derive Ne/H, S/H and Ne/S vs. RG. Important advantages compared with prior optical studies are: 1) the IR lines have a weak and similar electron temperature (Te) dependence while optical lines vary exponentially with Te and 2) the IR lines suffer far less from interstellar extinction. Additionally, these data may be used as constraints on the ionizing spectral energy distribution for the stars exciting these nebulae by comparing the above ionic ratios with predictions using stellar atmosphere models from several different non-LTE model sets. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407

High-brightness fiber-coupled pump laser development

Science.gov (United States)

Price, Kirk; Karlsen, Scott; Leisher, Paul; Martinsen, Robert

2010-02-01

We report on the continued development of high brightness laser diode modules at nLIGHT Photonics. These modules, based on nLIGHT's PearlTM product platform, demonstrate excellence in output power, brightness, wavelength stabilization, and long wavelength performance. This system, based on 14 single emitters, is designed to couple diode laser light into a 105 μm fiber at an excitation NA of under 0.14. We demonstrate over 100W of optical power at 9xx nm with a diode brightness exceeding 20 MW/cm2-str with an operating efficiency of approximately 50%. Additional results show over 70W of optical coupled at 8xx nm. Record brilliance at wavelengths 14xx nm and longer will also be demonstrated, with over 15 W of optical power with a beam quality of 7.5 mm-mrad. These results of high brightness, high efficiency, and wavelength stabilization demonstrate the pump technology required for next generation solid state and fiber lasers.

Providing Bright-Hard X-ray Beams from a Lower Energy Light Source

Science.gov (United States)

Robin, David

2002-04-01

At the Advanced Light Source (ALS) there had been an increasing demand for more high brightness harder X-ray sources in the 7 to 40 KeV range. In response to that demand, the ALS storage ring was modified in August 2001. Three 1.3 Tesla normal conducting bending magnets were removed and replaced with three 5 Tesla superconducting magnets (Superbends). The radiation produced by these Superbends is an order of magnitude higher in photon brightness and flux at 12 keV than the 1.3 Tesla bends, making them excellent sources of harder x-rays for protein crystallography and other harder x-ray applications. At the same time the Superbends do not compromise the performance of the facility in the UV and Soft X-ray regions of the spectrum. The Superbends will eventually feed 12 new x-ray beam lines greatly enhancing the facility's capacity in the hard x-ray region. The Superbend project is the biggest upgrade to the ALS storage ring since the ring was commissioned in 1993. In this paper we present, a history of the project, details of the magnet, installation, commissioning, and resulting performance of the ALS with Superbends.

Are Proplyds the Low-Energy Counterpart of Clouds Populating the AGNs Broad Line Region?

Science.gov (United States)

Dottori, H.

2000-11-01

The stability of the clouds producing the broadening of permitted lines in A GNs is a challenge for the persistence of these features during the galactic nucleus active fase lifetime. The formation of succesive generations of clouds in this very agressive enviroment, seems not to be the more adequated scenarion to explain this phenomenon. Why should new clouds be formed in regions where the UV radiation is so intense as to destroy the previously existing ones? The discovery of proplyds in Orion and NGC3603, as well as in 30Dor, shows that the formation of stars with protostars with surrounding disk is a common phenomenon in HII regions with very different radiation fields. We discuss that as a mechanism to explain the persistence of the clouds in the AGNs broad line regions.

The surface brightness of spiral galaxies

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.

1983-01-01

It is proposed that Freeman's discovery that the extrapolated central surface brightness of spiral galaxies is approximately constant can be simply explained if the galaxies contain a spheroidal component which dominates the light in their outer isophotes. Calculations of an effective central surface brightness indicate a wide spread of values. This requires either a wide spread in disc properties or significant spheroidal components or, most probably, both. (author)

The effect of bright lines in environmental risk communication

International Nuclear Information System (INIS)

Wilson, K.N.; Desvousges, W.H.; Smith, K.V.; Payne, J.

1993-01-01

Bright lines in environmental risk communication refer to the specific levels at which an environmental risk becomes a serious health threat and action should be taken to mitigate its effects. This study examined the effect of ''bright lines'' in risk communication by emphasizing the radon exposure threshold level of 4 picocuries per liter. Specifically, the authors developed a computer-assisted interview containing bright-line versions of risk information. The bright-line version contained a range of possible radon levels, the corresponding number of estimated lung cancer cases, the relative health risk from radon compared to other health risks, and the EPA guidelines for mitigating levels above 4 picocuries in the home. The non-bright line version was identical to the bright-line version, except it did not include the EPA's mitigation recommendations. Effect measures included respondents' change in perceived risk after reading their materials, intended testing behavior, and advice to their neighbor for a specified radon level either above or below the 4 picocury threshold level. This paper discusses broader policy implications for designing effective risk communication programs

Bright boys the making of information technology

CERN Document Server

Green, Tom

2010-01-01

Everything has a beginning. None was more profound-and quite as unexpected-than Information Technology. Here for the first time is the untold story of how our new age came to be and the bright boys who made it happen. What began on the bare floor of an old laundry building eventually grew to rival in size the Manhattan Project. The unexpected consequence of that journey was huge---what we now know as Information Technology. For sixty years the bright boys have been totally anonymous while their achievements have become a way of life for all of us. "Bright Boys" brings them home. By 1950 they'd

The Light and Dark Face of a Star-Forming Nebula

Science.gov (United States)

2010-03-01

Today, ESO is unveiling an image of the little known Gum 19, a faint nebula that, in the infrared, appears dark on one half and bright on the other. On one side hot hydrogen gas is illuminated by a supergiant blue star called V391 Velorum. New star formation is taking place within the ribbon of luminous and dark material that brackets V391 Velorum's left in this perspective. After many millennia, these fledgling stars, coupled with the explosive demise of V391 Velorum as a supernova, will likely alter Gum 19's present Janus-like appearance. Gum 19 is located in the direction of the constellation Vela (the Sail) at a distance of approximately 22 000 light years. The Gum 19 moniker derives from a 1955 publication by the Australian astrophysicist Colin S. Gum that served as the first significant survey of so-called HII (read "H-two") regions in the southern sky. HII refers to hydrogen gas that is ionised, or energised to the extent that the hydrogen atoms lose their electrons. Such regions emit light at well-defined wavelengths (or colours), thereby giving these cosmic clouds their characteristic glow. And indeed, much like terrestrial clouds, the shapes and textures of these HII regions change as time passes, though over the course of eons rather than before our eyes. For now, Gum 19 has somewhat of a science fiction-esque, "rip in spacetime" look to it in this image, with a narrow, near-vertical bright region slashing across the nebula. Looking at it, you could possibly see a resemblance to a two-toned angelfish or an arrow with a darkened point. This new image of the evocative Gum 19 object was captured by an infrared instrument called SOFI, mounted on ESO's New Technology Telescope (NTT) that operates at the La Silla Observatory in Chile. SOFI stands for Son of ISAAC, after the "father" instrument, ISAAC, that is located at ESO's Very Large Telescope observatory at Paranal to the north of La Silla. Observing this nebula in the infrared allows astronomers to see

The surface brightness of spiral galaxies

International Nuclear Information System (INIS)

Disney, M.; Phillipps, S.

1985-01-01

The intrinsic surface brightness Ssub(e) of 500 disc galaxies (0<=T<=9) drawn from the Second Reference Catalogue is computed and it is shown that Ssub(e) does not correlate significantly with Msub(B), (B-V) or type. This is consistent with the notion that there is a heavy selection bias in favour of disc galaxies with that particular surface brightness which allows inclusion in the catalogue over the largest volume of space. (author)

The distribution of star formation and metals in the low surface brightness galaxy UGC 628

Science.gov (United States)

Young, J. E.; Kuzio de Naray, Rachel; Wang, Sharon X.

2015-09-01

We introduce the MUSCEL Programme (MUltiwavelength observations of the Structure, Chemistry and Evolution of LSB galaxies), a project aimed at determining the star-formation histories of low surface brightness galaxies. MUSCEL utilizes ground-based optical spectra and space-based UV and IR photometry to fully constrain the star-formation histories of our targets with the aim of shedding light on the processes that led low surface brightness galaxies down a different evolutionary path from that followed by high surface brightness galaxies, such as our Milky Way. Here we present the spatially resolved optical spectra of UGC 628, observed with the VIRUS-P IFU at the 2.7-m Harlen J. Smith Telescope at the McDonald Observatory, and utilize emission-line diagnostics to determine the rate and distribution of star formation as well as the gas-phase metallicity and metallicity gradient. We find highly clustered star formation throughout UGC 628, excluding the core regions, and a log(O/H) metallicity around -4.2, with more metal-rich regions near the edges of the galactic disc. Based on the emission-line diagnostics alone, the current mode of star formation, slow and concentrated in the outer disc, appears to have dominated for quite some time, although there are clear signs of a much older stellar population formed in a more standard inside-out fashion.

SURFACE PHOTOMETRY OF LOW SURFACE BRIGHTNESS GALAXIES

NARCIS (Netherlands)

DEBLOK, WJG; VANDERHULST, JM; BOTHUN, GD

1995-01-01

Low surface brightness (LSB) galaxies are galaxies dominated by an exponential disc whose central surface brightness is much fainter than the value of mu(B)(0) = 21.65 +/- 0.30 mag arcsec(-2) found by Freeman. In this paper we present broadband photometry of a sample of 21 late-type LSB galaxies.

Bright points and ejections observed on the sun by the KORONAS-FOTON instrument TESIS

Science.gov (United States)

Ulyanov, A. S.; Bogachev, S. A.; Kuzin, S. V.

2010-10-01

Five-second observations of the solar corona carried out in the FeIX 171 Å line by the KORONAS-FOTON instrument TESIS are used to study the dynamics of small-scale coronal structures emitting in and around coronal bright points. The small-scale structures of the lower corona display complex dynamics similar to those of magnetic loops located at higher levels of the solar corona. Numerous detected oscillating structures with sizes below 10 000 km display oscillation periods from 50 to 350 s. The period distributions of these structures are different for P 150 s, which implies that different oscillation modes are excited at different periods. The small-scale structures generate numerous flare-like events with energies 1024-1026 erg (nanoflares) and with a spatial density of one event per arcsecond or more observed over an area of 4 × 1011 km2. Nanoflares are not associated with coronal bright points, and almost uniformly cover the solar disk in the observation region. The ejections of solar material from the coronal bright points demonstrate velocities of 80-110 km/s.

The outer disks of early-type galaxies. I. Surface-brightness profiles of barred galaxies

NARCIS (Netherlands)

Erwin, Peter; Pohlen, Michael; Beckman, John E.

We present a study of 66 barred, early-type (S0-Sb) disk galaxies, focused on the disk surface brightness profile outside the bar region, with the aim of throwing light on the nature of Freeman type I and II profiles, their origins, and their possible relation to disk truncations. This paper

A VLT spectroscopic study of the ultracompact HII region G29.96-0.02

NARCIS (Netherlands)

Martin-Hernandez, NL; Bik, A; Kaper, L; Tielens, AGGM; Hanson, MM

A high quality, medium-resolution K-band spectrum has been obtained of the ultracompact H II region G29.96-0.02 with the Very Large Telescope (VLT). The slit was positioned along the symmetry axis of the cometary shaped nebula. Besides the spectrum of the embedded ionizing O star, the long-slit

PePSS - A portable sky scanner for measuring extremely low night-sky brightness

Science.gov (United States)

Kocifaj, Miroslav; Kómar, Ladislav; Kundracik, František

2018-05-01

A new portable sky scanner designed for low-light-level detection at night is developed and employed in night sky brightness measurements in a rural region. The fast readout, adjustable sensitivity and linear response guaranteed in 5-6 orders of magnitude makes the device well suited for narrow-band photometry in both dark areas and bright urban and suburban environments. Quasi-monochromatic night-sky brightness data are advantageous in the accurate characterization of spectral power distribution of scattered and emitted light and, also allows for the possibility to retrieve light output patterns from whole-city light sources. The sky scanner can operate in both night and day regimes, taking advantage of the complementarity of both radiance data types. Due to its inherent very high sensitivity the photomultiplier tube could be used in night sky radiometry, while the spectrometer-equipped system component capable of detecting elevated intensities is used in daylight monitoring. Daylight is a source of information on atmospheric optical properties that in turn are necessary in processing night sky radiances. We believe that the sky scanner has the potential to revolutionize night-sky monitoring systems.

Suzaku observations of low surface brightness cluster Abell 1631

Science.gov (United States)

Babazaki, Yasunori; Mitsuishi, Ikuyuki; Ota, Naomi; Sasaki, Shin; Böhringer, Hans; Chon, Gayoung; Pratt, Gabriel W.; Matsumoto, Hironori

2018-04-01

We present analysis results for a nearby galaxy cluster Abell 1631 at z = 0.046 using the X-ray observatory Suzaku. This cluster is categorized as a low X-ray surface brightness cluster. To study the dynamical state of the cluster, we conduct four-pointed Suzaku observations and investigate physical properties of the Mpc-scale hot gas associated with the A 1631 cluster for the first time. Unlike relaxed clusters, the X-ray image shows no strong peak at the center and an irregular morphology. We perform spectral analysis and investigate the radial profiles of the gas temperature, density, and entropy out to approximately 1.5 Mpc in the east, north, west, and south directions by combining with the XMM-Newton data archive. The measured gas density in the central region is relatively low (a few ×10-4 cm-3) at the given temperature (˜2.9 keV) compared with X-ray-selected clusters. The entropy profile and value within the central region (r < 0.1 r200) are found to be flatter and higher (≳400 keV cm2). The observed bolometric luminosity is approximately three times lower than that expected from the luminosity-temperature relation in previous studies of relaxed clusters. These features are also observed in another low surface brightness cluster, Abell 76. The spatial distributions of galaxies and the hot gas appear to be different. The X-ray luminosity is relatively lower than that expected from the velocity dispersion. A post-merger scenario may explain the observed results.

The surface brightness of spiral galaxies: Pt. 4

International Nuclear Information System (INIS)

Phillipps, S.; Disney, M.; Ohio State Univ., Columbus

1988-01-01

Using measurements from IRAS correlations are found between optical surface brightness and both infrared-to-optical flux ratio and infrared colour temperature, in the sense that galaxies with high surface brightness have higher FIR emission and higher temperatures. (author)

Giant Low Surface Brightness Galaxies

Science.gov (United States)

Mishra, Alka; Kantharia, Nimisha G.; Das, Mousumi

2018-04-01

In this paper, we present radio observations of the giant low surface brightness (LSB) galaxies made using the Giant Metrewave Radio Telescope (GMRT). LSB galaxies are generally large, dark matter dominated spirals that have low star formation efficiencies and large HI gas disks. Their properties suggest that they are less evolved compared to high surface brightness galaxies. We present GMRT emission maps of LSB galaxies with an optically-identified active nucleus. Using our radio data and archival near-infrared (2MASS) and near-ultraviolet (GALEX) data, we studied morphology and star formation efficiencies in these galaxies. All the galaxies show radio continuum emission mostly associated with the centre of the galaxy.

Brightness waves of electroluminescence in ZnO:La electroluminor

International Nuclear Information System (INIS)

Bhushan, S.; Pandey, A.N.; Kaza, Balakrishna Rao

1979-01-01

A cryostat for the measurement of different luminescent characteristics from liquid N 2 temperature to above has been fabricated. Using this cryostat brightness waves due to sinusoidal excitations for ZnO:La electroluminor (EL) has been studied at different temperatures from -168deg C. Brightness waves for this system consist of two primary peaks during each cycle of excitation. Each primary peak is associated with a secondary peak. This secondary peak at -168deg C exists at the left arm of the primary peak. As the temperature is increased to 18deg C it moves towards the right arm of the primary peak. At an intermediate temperature the secondary peaks are most pronounced. Possible mechanism for these phenomena have been discussed. Temperature dependence of time averaged EL brightness for this system has also been studied and three peaks have been found. The results of brightness waves have also been discussed in the light of temperature dependence of time averaged EL brightness. (auth.)

Intrinsic brightness temperatures of blazar jets at 15 GHz

Directory of Open Access Journals (Sweden)

Hovatta Talvikki

2013-12-01

Full Text Available We have developed a new Bayesian Markov Chain Monte Carlo method to deconvolve light curves of blazars into individual flares, including proper estimation of the fit errors. We use the method to fit 15GHzlight curves obtained within the OVRO 40-m blazar monitoring program where a large number of AGN have been monitored since 2008 in support of the Fermi Gamma-Ray Space Telescope mission. The time scales obtained from the fitted models are used to calculate the variability brightness temperature of the sources. Additionally, we have calculated brightness temperatures of a sample of these objects using Very Long Baseline Array data from the MOJAVE survey. Combining these two data sets enables us to study the intrinsic brightness temperature distribution in these blazars at 15 GHz. Our preliminary results indicate that the mean intrinsic brightness temperature in a sample of 14 sources is near the equipartition brightness temperature of ~ 1011K.

High-brightness injector modeling

International Nuclear Information System (INIS)

Lewellen, J.W.

2004-01-01

There are many aspects to the successful conception, design, fabrication, and operation of high-brightness electron beam sources. Accurate and efficient modeling of the injector are critical to all phases of the process, from evaluating initial ideas to successful diagnosis of problems during routine operation. The basic modeling tasks will vary from design to design, according to the basic nature of the injector (dc, rf, hybrid, etc.), the type of cathode used (thermionic, photo, field emitter, etc.), and 'macro' factors such as average beam current and duty factor, as well as the usual list of desired beam properties. The injector designer must be at least aware of, if not proficient at addressing, the multitude of issues that arise from these considerations; and, as high-brightness injectors continue to move out of the laboratory, the number of such issues will continue to expand.

Changes in X-ray brightness of a solar active region

Energy Technology Data Exchange (ETDEWEB)

Glencross, W M; Brabban, D H [University Coll., London (UK). Mullard Space Science Lab.

1976-04-01

The soft X-ray flux in the waveband 0.3 to 0.9 nm has been monitored during most of the solar disk passage of McMath region 12094. These data show how the emission changed during quiet periods as well as during flaring. Throughout the first four days of observations the mean flux showed a gradual decay even though the magnetic region was still growing. At the end of this phase the region remained extremely inactive for almost half a day and then brightened by more than an order of magnitude within an hour. This enhancement lasted nearly one day and marked the onset of the break-up of the region. It is shown how this sequence of events might reflect the changes in subphotospheric convection pattern which Meyer et al (Mon. Not. R. Astr. Soc.; 169:35 (1974)) consider to develop in magnetic regions. It is also pointed out that the large flares in region 11976 during early 1972 August had a number of characteristics in common with the active phase discussed for region 12094.

Stunningly bright optical emission

Science.gov (United States)

Heinke, Craig O.

2017-12-01

The detection of bright, rapid optical pulsations from pulsar PSR J1023+0038 have provided a surprise for researchers working on neutron stars. This discovery poses more questions than it answers and will spur on future work and instrumentation.

LARGER PLANET RADII INFERRED FROM STELLAR ''FLICKER'' BRIGHTNESS VARIATIONS OF BRIGHT PLANET-HOST STARS

International Nuclear Information System (INIS)

Bastien, Fabienne A.; Stassun, Keivan G.; Pepper, Joshua

2014-01-01

Most extrasolar planets have been detected by their influence on their parent star, typically either gravitationally (the Doppler method) or by the small dip in brightness as the planet blocks a portion of the star (the transit method). Therefore, the accuracy with which we know the masses and radii of extrasolar planets depends directly on how well we know those of the stars, the latter usually determined from the measured stellar surface gravity, log g. Recent work has demonstrated that the short-timescale brightness variations ( f licker ) of stars can be used to measure log g to a high accuracy of ∼0.1-0.2 dex. Here, we use flicker measurements of 289 bright (Kepmag < 13) candidate planet-hosting stars with T eff = 4500-6650 K to re-assess the stellar parameters and determine the resulting impact on derived planet properties. This re-assessment reveals that for the brightest planet-host stars, Malmquist bias contaminates the stellar sample with evolved stars: nearly 50% of the bright planet-host stars are subgiants. As a result, the stellar radii, and hence the radii of the planets orbiting these stars, are on average 20%-30% larger than previous measurements had suggested

Beam brightness calculation for analytical and empirical distribution functions

International Nuclear Information System (INIS)

Myers, T.J.; Boulais, K.A.; O, Y.S.; Rhee, M.J.

1992-01-01

The beam brightness, a figure of merit for a beam quality useful for high-current low-emittance beams, was introduced by van Steenbergen as B = I/V 4 , where I is the beam current and V 4 is the hypervolume in the four-dimensional trace space occupied by the beam particles. Customarily, the brightness is expressed in terms of the product of emittances ε x ε y as B = ηI/(π 2 ε x ε y ), where η is a form factor of order unity which depends on the precise definition of emittance and hypervolume. Recently, a refined definition of the beam brightness based on the arithmetic mean value defined in statistics is proposed. The beam brightness is defined as B triple-bond 4 > = I -1 ∫ ρ 4 2 dxdydx'dy', where I is the beam current given by I ∫ ρ 4 dxdydx'dy'. Note that in this definition, neither the hypervolume V 4 nor the emittance, are explicitly used; the brightness is determined solely by the distribution function. Brightnesses are unambiguously calculated and expressed analytically in terms of the respective beam current and effective emittance for a few commonly used distribution functions, including Maxwellian and water-bag distributions. Other distributions of arbitrary shape frequently encountered in actual experiments are treated numerically. The resulting brightnesses are expressed in the form B = ηI/(π 2 ε x ε y ), and η is found to be weakly dependent on the form of velocity distribution as well as spatial distribution

Color and emotion: effects of hue, saturation, and brightness.

Science.gov (United States)

Wilms, Lisa; Oberfeld, Daniel

2017-06-13

Previous studies on emotional effects of color often failed to control all the three perceptual dimensions of color: hue, saturation, and brightness. Here, we presented a three-dimensional space of chromatic colors by independently varying hue (blue, green, red), saturation (low, medium, high), and brightness (dark, medium, bright) in a factorial design. The 27 chromatic colors, plus 3 brightness-matched achromatic colors, were presented via an LED display. Participants (N = 62) viewed each color for 30 s and then rated their current emotional state (valence and arousal). Skin conductance and heart rate were measured continuously. The emotion ratings showed that saturated and bright colors were associated with higher arousal. The hue also had a significant effect on arousal, which increased from blue and green to red. The ratings of valence were the highest for saturated and bright colors, and also depended on the hue. Several interaction effects of the three color dimensions were observed for both arousal and valence. For instance, the valence ratings were higher for blue than for the remaining hues, but only for highly saturated colors. Saturated and bright colors caused significantly stronger skin conductance responses. Achromatic colors resulted in a short-term deceleration in the heart rate, while chromatic colors caused an acceleration. The results confirm that color stimuli have effects on the emotional state of the observer. These effects are not only determined by the hue of a color, as is often assumed, but by all the three color dimensions as well as their interactions.

Quantitative Brightness Analysis of Fluorescence Intensity Fluctuations in E. Coli.

Directory of Open Access Journals (Sweden)

Kwang-Ho Hur

Full Text Available The brightness measured by fluorescence fluctuation spectroscopy specifies the average stoichiometry of a labeled protein in a sample. Here we extended brightness analysis, which has been mainly applied in eukaryotic cells, to prokaryotic cells with E. coli serving as a model system. The small size of the E. coli cell introduces unique challenges for applying brightness analysis that are addressed in this work. Photobleaching leads to a depletion of fluorophores and a reduction of the brightness of protein complexes. In addition, the E. coli cell and the point spread function of the instrument only partially overlap, which influences intensity fluctuations. To address these challenges we developed MSQ analysis, which is based on the mean Q-value of segmented photon count data, and combined it with the analysis of axial scans through the E. coli cell. The MSQ method recovers brightness, concentration, and diffusion time of soluble proteins in E. coli. We applied MSQ to measure the brightness of EGFP in E. coli and compared it to solution measurements. We further used MSQ analysis to determine the oligomeric state of nuclear transport factor 2 labeled with EGFP expressed in E. coli cells. The results obtained demonstrate the feasibility of quantifying the stoichiometry of proteins by brightness analysis in a prokaryotic cell.

Brightness of the photosphere and faculae at the limb according to eclipse observations

Energy Technology Data Exchange (ETDEWEB)

Akimov, L.A.; Belkina, I.L.; Dyatel, N.P. (Khar' kovskij Gosudarstvennyj Univ. (Ukrainian SSR). Astronomicheskaya Observatoriya)

The absolute integrated and surface brightness distributions of the photospheric continuum (lambda approximately 5870 A) and faculae at the extreme limb are obtained from July 10, 1972 solar eclipse slitless spectrograms. Some possible reasons of the limb brightening in the surface brightness distributions of the photosphere are discussed. It is detected that facular contrasts have the high values, up to 1.76 for the height about 200 km. This fact shows that radiation and matter density changes depending on height in the upper atmosphere in a facula more quickly than outside the facula. The comparison of the observed moments of local contacts with the theoretical ones, based on the lunar limb relief data, has shown that the active regions are approximately 300 km higher than the photosphere. The schematic model of the photospheric faculae is given.

Brightness of the photosphere and faculae at the limb according to eclipse observations

International Nuclear Information System (INIS)

Akimov, L.A.; Belkina, I.L.; Dyatel, N.P.

1982-01-01

The absolute integrated and surface brightness distributions of the photospheric continuum (lambda approximately 5870 A) and faculae at the extreme limb are obtained from July 10, 1972 solar eclipse slitless spectrograms. Some possible reasons of the limb brightening in the surface brightness distributions of the photosphere are discussed. It is detected that facular contrasts have the high values, up to 1.76 for the height about 200 km. This fact shows that radiation and matter density changes depending on height in the upper atmosphere in a facula more quickly than outside the facula. The comparison of the observed moments of local contacts with the theoretical ones, based on the lunar limb relief data, has shown that the active regions are approximately 300 km higher than the photosphere. The schematic model of the photospheric faculae is given

Lamp spectrum and spatial brightness at photopic levels

DEFF Research Database (Denmark)

Fotios, Steve; Atli, Deniz; Cheal, Chris

2015-01-01

Light sources are available in a variety of spectral power distributions (SPDs) and this affects spatial brightness in a manner not predicted by quantities such as illuminance. Tuning light source SPD to better match the sensitivity of visual perception may allow the same spatial brightness but a...

Visible Color and Photometry of Bright Materials on Vesta

Science.gov (United States)

Schroder, S. E.; Li, J. Y.; Mittlefehldt, D. W.; Pieters, C. M.; De Sanctis, M. C.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Keller, H. U.

2012-01-01

The Dawn Framing Camera (FC) collected images of the surface of Vesta at a pixel scale of 70 m in the High Altitude Mapping Orbit (HAMO) phase through its clear and seven color filters spanning from 430 nm to 980 nm. The surface of Vesta displays a large diversity in its brightness and colors, evidently related to the diverse geology [1] and mineralogy [2]. Here we report a detailed investigation of the visible colors and photometric properties of the apparently bright materials on Vesta in order to study their origin. The global distribution and the spectroscopy of bright materials are discussed in companion papers [3, 4], and the synthesis results about the origin of Vestan bright materials are reported in [5].

Human CD56bright NK Cells

DEFF Research Database (Denmark)

Michel, Tatiana; Poli, Aurélie; Cuapio, Angelica

2016-01-01

Human NK cells can be subdivided into various subsets based on the relative expression of CD16 and CD56. In particular, CD56(bright)CD16(-/dim) NK cells are the focus of interest. They are considered efficient cytokine producers endowed with immunoregulatory properties, but they can also become c...... NK cell subsets is not fully defined, nor is their precise hematopoietic origin. In this article, we summarize recent studies about CD56(bright) NK cells in health and disease and briefly discuss the current controversies surrounding them....

Music for a Brighter World: Brightness Judgment Bias by Musical Emotion.

Science.gov (United States)

Bhattacharya, Joydeep; Lindsen, Job P

2016-01-01

A prevalent conceptual metaphor is the association of the concepts of good and evil with brightness and darkness, respectively. Music cognition, like metaphor, is possibly embodied, yet no study has addressed the question whether musical emotion can modulate brightness judgment in a metaphor consistent fashion. In three separate experiments, participants judged the brightness of a grey square that was presented after a short excerpt of emotional music. The results of Experiment 1 showed that short musical excerpts are effective emotional primes that cross-modally influence brightness judgment of visual stimuli. Grey squares were consistently judged as brighter after listening to music with a positive valence, as compared to music with a negative valence. The results of Experiment 2 revealed that the bias in brightness judgment does not require an active evaluation of the emotional content of the music. By applying a different experimental procedure in Experiment 3, we showed that this brightness judgment bias is indeed a robust effect. Altogether, our findings demonstrate a powerful role of musical emotion in biasing brightness judgment and that this bias is aligned with the metaphor viewpoint.

Bright Solitons in a PT-Symmetric Chain of Dimers

Directory of Open Access Journals (Sweden)

Omar B. Kirikchi

2016-01-01

Full Text Available We study the existence and stability of fundamental bright discrete solitons in a parity-time- (PT- symmetric coupler composed by a chain of dimers that is modelled by linearly coupled discrete nonlinear Schrödinger equations with gain and loss terms. We use a perturbation theory for small coupling between the lattices to perform the analysis, which is then confirmed by numerical calculations. Such analysis is based on the concept of the so-called anticontinuum limit approach. We consider the fundamental onsite and intersite bright solitons. Each solution has symmetric and antisymmetric configurations between the arms. The stability of the solutions is then determined by solving the corresponding eigenvalue problem. We obtain that both symmetric and antisymmetric onsite mode can be stable for small coupling, in contrast to the reported continuum limit where the antisymmetric solutions are always unstable. The instability is either due to the internal modes crossing the origin or the appearance of a quartet of complex eigenvalues. In general, the gain-loss term can be considered parasitic as it reduces the stability region of the onsite solitons. Additionally, we analyse the dynamic behaviour of the onsite and intersite solitons when unstable, where typically it is either in the form of travelling solitons or soliton blow-ups.

Simultaneous brightness contrast of foraging Papilio butterflies

Science.gov (United States)

Kinoshita, Michiyo; Takahashi, Yuki; Arikawa, Kentaro

2012-01-01

This study focuses on the sense of brightness in the foraging Japanese yellow swallowtail butterfly, Papilio xuthus. We presented two red discs of different intensity on a grey background to butterflies, and trained them to select one of the discs. They were successfully trained to select either a high intensity or a low intensity disc. The trained butterflies were tested on their ability to perceive brightness in two different protocols: (i) two orange discs of different intensity presented on the same intensity grey background and (ii) two orange discs of the same intensity separately presented on a grey background that was either higher or lower in intensity than the training background. The butterflies trained to high intensity red selected the orange disc of high intensity in protocol 1, and the disc on the background of low intensity grey in protocol 2. We obtained similar results in another set of experiments with purple discs instead of orange discs. The choices of the butterflies trained to low intensity red were opposite to those just described. Taken together, we conclude that Papilio has the ability to learn brightness and darkness of targets independent of colour, and that they have the so-called simultaneous brightness contrast. PMID:22179808

The ASAS-SN bright supernova catalogue - III. 2016

DEFF Research Database (Denmark)

Holoien, T. W. -S.; Brown, J. S.; Stanek, K. Z.

2017-01-01

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d......This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (m(peak)d...

Bright THz Instrument and Nonlinear THz Science

Science.gov (United States)

2017-10-30

Report: Bright THz Instrument and Nonlinear THz Science The views, opinions and/or findings contained in this report are those of the author(s) and...Number: W911NF-16-1-0436 Organization: University of Rochester Title: Bright THz Instrument and Nonlinear THz Science Report Term: 0-Other Email: xi...exploring new cutting-edge research and broader applications, following the significant development of THz science and technology in the late 80’s, is the

Music for a Brighter World: Brightness Judgment Bias by Musical Emotion.

Directory of Open Access Journals (Sweden)

Joydeep Bhattacharya

Full Text Available A prevalent conceptual metaphor is the association of the concepts of good and evil with brightness and darkness, respectively. Music cognition, like metaphor, is possibly embodied, yet no study has addressed the question whether musical emotion can modulate brightness judgment in a metaphor consistent fashion. In three separate experiments, participants judged the brightness of a grey square that was presented after a short excerpt of emotional music. The results of Experiment 1 showed that short musical excerpts are effective emotional primes that cross-modally influence brightness judgment of visual stimuli. Grey squares were consistently judged as brighter after listening to music with a positive valence, as compared to music with a negative valence. The results of Experiment 2 revealed that the bias in brightness judgment does not require an active evaluation of the emotional content of the music. By applying a different experimental procedure in Experiment 3, we showed that this brightness judgment bias is indeed a robust effect. Altogether, our findings demonstrate a powerful role of musical emotion in biasing brightness judgment and that this bias is aligned with the metaphor viewpoint.

Using the Chandra Source-Finding Algorithm to Automatically Identify Solar X-ray Bright Points

Science.gov (United States)

Adams, Mitzi L.; Tennant, A.; Cirtain, J. M.

2009-01-01

This poster details a technique of bright point identification that is used to find sources in Chandra X-ray data. The algorithm, part of a program called LEXTRCT, searches for regions of a given size that are above a minimum signal to noise ratio. The algorithm allows selected pixels to be excluded from the source-finding, thus allowing exclusion of saturated pixels (from flares and/or active regions). For Chandra data the noise is determined by photon counting statistics, whereas solar telescopes typically integrate a flux. Thus the calculated signal-to-noise ratio is incorrect, but we find we can scale the number to get reasonable results. For example, Nakakubo and Hara (1998) find 297 bright points in a September 11, 1996 Yohkoh image; with judicious selection of signal-to-noise ratio, our algorithm finds 300 sources. To further assess the efficacy of the algorithm, we analyze a SOHO/EIT image (195 Angstroms) and compare results with those published in the literature (McIntosh and Gurman, 2005). Finally, we analyze three sets of data from Hinode, representing different parts of the decline to minimum of the solar cycle.

Richard Bright and his neurological studies.

Science.gov (United States)

Pearce, J M S

2009-01-01

Richard Bright was one of the famous triumvirate of Guy's Hospital physicians in the Victorian era. Remembered for his account of glomerulonephritis (Bright's disease) he also made many important and original contributions to medicine and neurology. These included his work on cortical epileptogenesis, descriptions of simple partial (Jacksonian) seizures, infantile convulsions, and a variety of nervous diseases. Most notable were his reports of neurological studies including papers on traumatic tetanus, syringomyelia, arteries of the brain, contractures of spinal origin, tumours of the base of the brain, and narcolepsy. His career and these contributions are outlined. Copyright 2009 S. Karger AG, Basel.

Sky brightness and twilight measurements at Jogyakarta city, Indonesia

International Nuclear Information System (INIS)

Herdiwijaya, Dhani

2016-01-01

The sky brightness measurements were performed using a portable photometer. A pocket-sized and low-cost photometer has 20 degree area measurement, and spectral ranges between 320-720 nm with output directly in magnitudes per arc second square (mass) unit. The sky brightness with 3 seconds temporal resolutions was recorded at Jogyakarta city (110° 25’ E; 70° 52’ S; elevation 100 m) within 136 days in years from 2014 to 2016. The darkest night could reach 22.61 mpass only in several seconds, with mean value 18.8±0.7 mpass and temperature variation 23.1±1.2 C. The difference of mean sky brightness between before and after midnight was about -0.76 mpass or 2.0 times brighter. Moreover, the sky brightness and temperature fluctuations were more stable in after midnight than in before midnight. It is suggested that city light pollution affects those variations, and subsequently duration of twilight. By comparing twilight brightness for several places, we also suggest a 17° solar dip or about 66 minutes before sunrise for new time of Fajr prayer. (paper)

Low dimensional neutron moderators for enhanced source brightness

DEFF Research Database (Denmark)

Mezei, Ferenc; Zanini, Luca; Takibayev, Alan

2014-01-01

In a recent numerical optimization study we have found that liquid para-hydrogen coupled cold neutron moderators deliver 3–5 times higher cold neutron brightness at a spallation neutron source if they take the form of a flat, quasi 2-dimensional disc, in contrast to the conventional more voluminous...... for cold neutrons. This model leads to the conclusions that the optimal shape for high brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and these low dimensional moderators can also deliver much enhanced cold neutron brightness in fission reactor neutron sources, compared...... to the much more voluminous liquid D2 or H2 moderators currently used. Neutronic simulation calculations confirm both of these theoretical conclusions....

Spatially single-mode source of bright squeezed vacuum

OpenAIRE

Pérez, A. M.; Iskhakov, T. Sh.; Sharapova, P.; Lemieux, S.; Tikhonova, O. V.; Chekhova, M. V.; Leuchs, G.

2014-01-01

Bright squeezed vacuum, a macroscopic nonclassical state of light, can be obtained at the output of a strongly pumped non-seeded traveling-wave optical parametric amplifier (OPA). By constructing the OPA of two consecutive crystals separated by a large distance we make the squeezed vacuum spatially single-mode without a significant decrease in the brightness or squeezing.

Radiation-hydrodynamics of HII regions and molecular clouds

International Nuclear Information System (INIS)

Sandford, M.T. II; Whitaker, R.W.; Klein, R.I.

1981-01-01

Two-dimensional calculations of ionization-shock fronts surrounding neutral cloud clumps reveal that a radiation-driven implosion of the clump can occur. The implosion of a cloud clump results in the formation of density enhancements that may eventually form low mass stars. The smaller globules produced may become Herbig-Haro objects, or maser sources

Bunsen Reaction using a HIx Solution (HI-I2-H2O with Countercurrent Flow for Sulfur-Iodine Hydrogen Production Process

Directory of Open Access Journals (Sweden)

Kim Hyo-Sub

2016-01-01

Full Text Available In the sulfur-iodine hydrogen production process, the Bunsen reaction is a crucial section because of the linkage with the H2SO4 and HI decomposition sections. The HIx solution (HI-I2-H2O mixture was fed to the Bunsen reaction section as a reactant from the HI decomposition section. In this study, the Bunsen reaction using the HIx solution with countercurrent flow was performed. The production rate of HIx phase solution increased while that of H2SO4 phase solution was maintained constant when increasing the flow rate of HIx solution. As the SO2 flow rate increased, the production rates of H2SO4 and HIx phase solutions increased. The amount of resultant H2SO4 phase was very lower than that of resultant HIx phase under the conditions examined in this study.

A New Sky Brightness Monitor

Science.gov (United States)

Crawford, David L.; McKenna, D.

2006-12-01

A good estimate of sky brightness and its variations throughout the night, the months, and even the years is an essential bit of knowledge both for good observing and especially as a tool in efforts to minimize sky brightness through local action. Hence a stable and accurate monitor can be a valuable and necessary tool. We have developed such a monitor, with the financial help of Vatican Observatory and Walker Management. The device is now undergoing its Beta test in preparation for production. It is simple, accurate, well calibrated, and automatic, sending its data directly to IDA over the internet via E-mail . Approximately 50 such monitors will be ready soon for deployment worldwide including most major observatories. Those interested in having one should enquire of IDA about details.

X-ray heating and ionization of broad-emission-line regions in QSO's and active galaxies

International Nuclear Information System (INIS)

Weisheit, J.C.; Shields, G.A.; Tarter, C.B.

1980-07-01

Absorption of x-rays deep within the broad-line emitting clouds in QSO's and the nuclei of active galaxies creates extensive zones of warm (T approx. 10 4 K), partially ionized N/sub e//N approx. 0.1) gas. Because Lyman alpha photons are trapped in these regions, the x-ray energy is efficiently channeled into Balmer lines collisionally excited from the n = 2 level. The HI regions plus the HII regions created by ultraviolet photons illuminating the surfaces of the clouds give rise to integrated Lα/Hα line emission ratios between 1 and 2. Enhanced MgII line emission from the HI regions gives rise to integrated MgII/Hα ratios near 0.5. The OI line lambda 8446 is efficiently pumped by trapped Hα photons and in the x-ray heated zone an intensity ratio I (lambda 8446)/I(Hα) approx. < 0.1 is calculated. All of these computed ratios now are in agreement with observations

Edge integration and the perception of brightness and darkness

NARCIS (Netherlands)

Vladusich, T.; Lucassen, M.P.; Cornelissen, F.W.

2006-01-01

How do induced brightness and darkness signals from local and remote surfaces interact to determine the final achromatic color percept of a target surface? An emerging theory of achromatic color perception posits that brightness and darkness percepts are computed by weighting and summing the

A model for the infrared emission from an OB star cluster environment

International Nuclear Information System (INIS)

Leisawitz, D.

1990-01-01

Researchers developed an interactive radiative transfer code that predicts the infrared emission from an HII region containing diffuse ionized and atomic gas and dense molecular clouds. This model complements the investigation of the redistribution of OB star luminosity in the interstellar medium (Leisawitz and Hauser 1988, Ap. J., 332, 954). The model can be used as a diagnostic tool to probe the radiation field and matter density in an HII region, place constraints on the proximity and orientation of an illuminated molecular cloud with respect to the ionizing stars, test for the presence of small, transiently heated dust grains, and determine whether the dust-to-gas ratio is normal. Predictions of the model agree qualitatively and quantitatively with observations of blister-type HII regions ionized by well-studied OB clusters in which the distribution of dense neutral material is known. This is illustrated by a model for Infrared Astronomy Satellite (IRAS) observations of the region around NGC 7380 (S142). Researchers plan to use the model in a survey of regions of massive star formation in the outer Galaxy to study OB stars embedded to various degrees in their parental molecular clouds

Chemical Abundances and Physical Parameters of H II Regions in the Magellanic Clouds

Science.gov (United States)

Reyes, R. E. C.

The chemical abundances and physical parameters of H II regions are important pa rameters to determine in order to understand how stars and galaxies evolve. The Magellanic Clouds offer us a unique oportunity to persue such studies in low metallicity galaxies. In this contribution we present the results of the photoionization modeling of 5 H II regions in each of the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) sys tems. Optical data were collected from the literature, complemented by our own observa tions (Carlos Reyes et al. 1998), including UV spectra from the new IUE data ban k and infrared fluxes from the IRAS satellite. The chemical abundances of He, C, N, O, Ne, S, Ar and physical parameters like the densities, the ionized masses, the luminosities, the ionization temperatures , the filling factor and optical depth are determined. A comparison of the abundances of these HII regions with those of typical planetary nebulae and supergiants stars is also presented.

High Brightness OLED Lighting

Energy Technology Data Exchange (ETDEWEB)

Spindler, Jeffrey [OLEDWorks LLC; Kondakova, Marina [OLEDWorks LLC; Boroson, Michael [OLEDWorks LLC; Hamer, John [OLEDWorks LLC

2016-05-25

In this work we describe the technology developments behind our current and future generations of high brightness OLED lighting panels. We have developed white and amber OLEDs with excellent performance based on the stacking approach. Current products achieve 40-60 lm/W, while future developments focus on achieving 80 lm/W or higher.

Radio Recombination Line Surveys of the inner Galactic Plane: SIGGMA and GDIGS

Science.gov (United States)

Liu, Bin; Anderson, Loren Dean; Luisi, Matteo; Balser, Dana; Bania, Thomas; Wenger, Trey; Haffner, Lawrence Matthew; Minchin, Robert; Roshi, Anish; Churchwell, Edward; Terzian, Yervant; McIntyre, Travis; Lebron, Mayra; SIGGMA team, GDIGS team

2018-01-01

Ionized gas is one of the primary components of the interstellar medium (ISM) and plays a crucial role in star formation and galaxy evolution. Radio recombination lines (RRLs) can directly trace ionized gas in HII regions and warm ionized medium (WIM) without being affected by interstellar extinction. Single-dish telescopes like Arecibo Observatory and the Green Bank Telescope (GBT) are sensitive to low surface brightness emission, and are therefore powerful tools for the study of HII regions and the WIM. We report here on two large surveys of RRL emission: The Survey of Ionized Gas in the Galaxy, Made with the Arecibo telescope (SIGGMA) and the GBT Diffuse Ionized Gas Survey (GDIGS). These are the first large-scale fully-sampled RRL surveys, and together cover nearly the entire first quadrant of the Galactic plane at ~arcmin spatial resolution (l = -5 - 32 deg. for GDIGS and l = 32 - 70 deg. for SIGGMA). SIGGMA is performed with the Arecibo L-band Feed Array (ALFA) receiver, whose bandpass covers twelve hydrogen alpha lines from H163α to H174α. By stacking the α-lines and smoothing to 4 km/s velocity resolution, the final SIGGMA spectra have a mean rms level of ~0.65 mJy per beam. The GDIGS data were taken with the GBT C-band receiver and the VEGAS backend and include RRLs from H95α to H117α, and when stacked and smoothed to 5 km/s resolution achieve 1 mJy per beam rms. Here, we report on early analysis of the SIGGMA and GDIGS data, and present first scientific results.

STARS4ALL Night Sky Brightness Photometer

Directory of Open Access Journals (Sweden)

Jaime Zamorano

2017-06-01

Full Text Available We present the main features of TESS-W, the first version of a series of inexpensive but reliable photometers that will be used to measure night sky brightness. The bandpass is extended to the red with respect of that of the Sky Quality Meter (SQM. TESS-W connects to a router via WIFI and it sends automatically the brightness values to a data repository using Internet of Things protocols. The device includes an infrared sensor to estimate the cloud coverage. It is designed for fixed stations to monitor the evolution of the sky brightness. The photometer could also be used in local mode connected to a computer or tablet to gather data from a moving vehicle. The photometer is being developed within STARS4ALL project, a collective awareness platform for promoting dark skies in Europe, funded by the EU. We intend to extend the existing professional networks to a citizen-based network of photometers. 

Bright environments vision of the Intelligent Lighting Institute (ILI)

NARCIS (Netherlands)

Özçelebi, T.

2014-01-01

The Bright Environments research program of the Eindhoven University of Technology Intelligent Lighting Institute aims to find new methods of intelligent lighting control and human interaction. We present a summary of the institute’s work on this research field and the research vision of the Bright

Hydrophobic nanoparticles promote lamellar to inverted hexagonal transition in phospholipid mesophases.

Science.gov (United States)

Bulpett, Jennifer M; Snow, Tim; Quignon, Benoit; Beddoes, Charlotte M; Tang, T-Y D; Mann, Stephen; Shebanova, Olga; Pizzey, Claire L; Terrill, Nicholas J; Davis, Sean A; Briscoe, Wuge H

2015-12-07

This study focuses on how the mesophase transition behaviour of the phospholipid dioleoyl phosphatidylethanolamine (DOPE) is altered by the presence of 10 nm hydrophobic and 14 nm hydrophilic silica nanoparticles (NPs) at different concentrations. The lamellar to inverted hexagonal phase transition (Lα-HII) of phospholipids is energetically analogous to the membrane fusion process, therefore understanding the Lα-HII transition with nanoparticulate additives is relevant to how membrane fusion may be affected by these additives, in this case the silica NPs. The overriding observation is that the HII/Lα boundaries in the DOPE p-T phase diagram were shifted by the presence of NPs: the hydrophobic NPs enlarged the HII phase region and thus encouraged the inverted hexagonal (HII) phase to occur at lower temperatures, whilst hydrophilic NPs appeared to stabilise the Lα phase region. This effect was also NP-concentration dependent, with a more pronounced effect for higher concentration of the hydrophobic NPs, but the trend was less clear cut for the hydrophilic NPs. There was no evidence that the NPs were intercalated into the mesophases, and as such it was likely that they might have undergone microphase separation and resided at the mesophase domain boundaries. Whilst the loci and exact roles of the NPs invite further investigation, we tentatively discuss these results in terms of both the surface chemistry of the NPs and the effect of their curvature on the elastic bending energy considerations during the mesophase transition.

Classification and correction of the radar bright band with polarimetric radar

Science.gov (United States)

Hall, Will; Rico-Ramirez, Miguel; Kramer, Stefan

2015-04-01

The annular region of enhanced radar reflectivity, known as the Bright Band (BB), occurs when the radar beam intersects a layer of melting hydrometeors. Radar reflectivity is related to rainfall through a power law equation and so this enhanced region can lead to overestimations of rainfall by a factor of up to 5, so it is important to correct for this. The BB region can be identified by using several techniques including hydrometeor classification and freezing level forecasts from mesoscale meteorological models. Advances in dual-polarisation radar measurements and continued research in the field has led to increased accuracy in the ability to identify the melting snow region. A method proposed by Kitchen et al (1994), a form of which is currently used operationally in the UK, utilises idealised Vertical Profiles of Reflectivity (VPR) to correct for the BB enhancement. A simpler and more computationally efficient method involves the formation of an average VPR from multiple elevations for correction that can still cause a significant decrease in error (Vignal 2000). The purpose of this research is to evaluate a method that relies only on analysis of measurements from an operational C-band polarimetric radar without the need for computationally expensive models. Initial results show that LDR is a strong classifier of melting snow with a high Critical Success Index of 97% when compared to the other variables. An algorithm based on idealised VPRs resulted in the largest decrease in error when BB corrected scans are compared to rain gauges and to lower level scans with a reduction in RMSE of 61% for rain-rate measurements. References Kitchen, M., R. Brown, and A. G. Davies, 1994: Real-time correction of weather radar data for the effects of bright band, range and orographic growth in widespread precipitation. Q.J.R. Meteorol. Soc., 120, 1231-1254. Vignal, B. et al, 2000: Three methods to determine profiles of reflectivity from volumetric radar data to correct

Dynamics of bright-bright solitons in Bose-Einstein condensate with Raman-induced one-dimensional spin-orbit coupling

Science.gov (United States)

Wen, Lin; Zhang, Xiao-Fei; Hu, Ai-Yuan; Zhou, Jing; Yu, Peng; Xia, Lei; Sun, Qing; Ji, An-Chun

2018-03-01

We investigate the dynamics of bright-bright solitons in one-dimensional two-component Bose-Einstein condensates with Raman-induced spin-orbit coupling, via the variational approximation and the numerical simulation of Gross-Pitaevskii equations. For the uniform system without trapping potential, we obtain two population balanced stationary solitons. By performing the linear stability analysis, we find a Goldstone eigenmode and an oscillation eigenmode around these stationary solitons. Moreover, we derive a general dynamical solution to describe the center-of-mass motion and spin evolution of the solitons under the action of spin-orbit coupling. The effects of a harmonic trap have also been discussed.

The Physics and Applications of High Brightness Electron Beams

Science.gov (United States)

Palumbo, Luigi; Rosenzweig, J.; Serafini, Luca

2007-09-01

.]. -- Working Group 1. Summary of working group 1 on electron sources / M. Ferrario and G. Gatti. Design and RF measurements of an X-band accelerating structure for the SPARC project / D. Alesini ... [et al.]. Mitigation of RF gun breakdown by removal of tuning rods in high field regions / A.M. Cook... [et al.]. Measurements of quantum efficiency of Mg films produced by pulsed laser ablation deposition for application to bright electron sources / G. Gatti ... [et al.]. The S-band 1.6 cell RF gun correlated energy spread dependence on Pi and 0 mode relative amplitude / F. Schmerge ... [et al.]. RF gun photo-emission model for metal cathodes including time dependent emission / J.F. Schmerge ... [et al.]. Superconducting photocathodes / J. Smedley ... [et al.]. -- Working Group 2. Summary of Working Group 2: diagnostics and beam manipulation / G. Travish. Observation of coherent edge radiation emitted by a 100 Femtosecond compressed electron beam / G. Andonian, M, Dunning, E. Hemsing, J. B. Rosenzweig ... [et al.]. PARMELA simulations for PITZ: first machine studies and interpretation of measurements / M. Boscolo ... [et al.]. The LCLS single-shot relative bunch length monitor system / M.P. Dunning ... [et al.]. Beam shaping and permanent magnet quadrupole focusing with applications to the plasma wakefield accelerator / R.J. England ... [et al.]. Commissioning of the SPARC movable emittance meter and its first operation at PITZ / D. Filippetto... [et al.]. Experimental testing of dynamically optimized photoelectron beams / J.B. Rosenzweig ... [et al.]. Synchronization between the laser and electron beam in a photocathode RF gun / A. Sakumi ... [et al.]. Method of bunch radiation photochronography with 10 Femtosecond and less resolution / A. Tron and I. Merinov -- Working Group 3. New challenges in theory and modeling-summary for working group 3. L. Giannessi. Resonant modes in a 1.6 cells RF gun / M. Ferrario and C. Ronsivalle. Emittance degradation due to wake fields in a high

Phase advancing human circadian rhythms with morning bright light, afternoon melatonin, and gradually shifted sleep: can we reduce morning bright-light duration?

Science.gov (United States)

Crowley, Stephanie J; Eastman, Charmane I

2015-02-01

Efficient treatments to phase-advance human circadian rhythms are needed to attenuate circadian misalignment and the associated negative health outcomes that accompany early-morning shift work, early school start times, jet lag, and delayed sleep phase disorder. This study compared three morning bright-light exposure patterns from a single light box (to mimic home treatment) in combination with afternoon melatonin. Fifty adults (27 males) aged 25.9 ± 5.1 years participated. Sleep/dark was advanced 1 h/day for three treatment days. Participants took 0.5 mg of melatonin 5 h before the baseline bedtime on treatment day 1, and an hour earlier each treatment day. They were exposed to one of three bright-light (~5000 lux) patterns upon waking each morning: four 30-min exposures separated by 30 min of room light (2-h group), four 15-min exposures separated by 45 min of room light (1-h group), and one 30-min exposure (0.5-h group). Dim-light melatonin onsets (DLMOs) before and after treatment determined the phase advance. Compared to the 2-h group (phase shift = 2.4 ± 0.8 h), smaller phase-advance shifts were seen in the 1-h (1.7 ± 0.7 h) and 0.5-h (1.8 ± 0.8 h) groups. The 2-h pattern produced the largest phase advance; however, the single 30-min bright-light exposure was as effective as 1 h of bright light spread over 3.25 h, and it produced 75% of the phase shift observed with 2 h of bright light. A 30-min morning bright-light exposure with afternoon melatonin is an efficient treatment to phase-advance human circadian rhythms. Copyright © 2014 Elsevier B.V. All rights reserved.

Phase advancing human circadian rhythms with morning bright light, afternoon melatonin, and gradually shifted sleep: can we reduce morning bright light duration?

Science.gov (United States)

Crowley, Stephanie J.; Eastman, Charmane I.

2015-01-01

OBJECTIVE Efficient treatments to phase advance human circadian rhythms are needed to attenuate circadian misalignment and the associated negative health outcomes that accompany early morning shift work, early school start times, jet lag, and delayed sleep phase disorder. This study compared three morning bright light exposure patterns from a single light box (to mimic home treatment) in combination with afternoon melatonin. METHODS Fifty adults (27 males) aged 25.9±5.1 years participated. Sleep/dark was advanced 1 hour/day for 3 treatment days. Participants took 0.5 mg melatonin 5 hours before baseline bedtime on treatment day 1, and an hour earlier each treatment day. They were exposed to one of three bright light (~5000 lux) patterns upon waking each morning: four 30-minute exposures separated by 30 minutes of room light (2 h group); four 15-minute exposures separated by 45 minutes of room light (1 h group), and one 30-minute exposure (0.5 h group). Dim light melatonin onsets (DLMOs) before and after treatment determined the phase advance. RESULTS Compared to the 2 h group (phase shift=2.4±0.8 h), smaller phase advance shifts were seen in the 1 h (1.7±0.7 h) and 0.5 h (1.8±0.8 h) groups. The 2-hour pattern produced the largest phase advance; however, the single 30-minute bright light exposure was as effective as 1 hour of bright light spread over 3.25 h, and produced 75% of the phase shift observed with 2 hours of bright light. CONCLUSIONS A 30-minute morning bright light exposure with afternoon melatonin is an efficient treatment to phase advance human circadian rhythms. PMID:25620199

Cooling Active Region Loops Observed With SXT and TRACE

OpenAIRE

Winebarger, Amy R.; Warren, Harry P.

2005-01-01

An Impulsive Heating Multiple Strand (IHMS) Model is able to reproduce the observational characteristics of EUV (~ 1 MK) active region loops. This model implies that some of the loops must reach temperatures where X-ray filters are sensitive (> 2.5 MK) before they cool to EUV temperatures. Hence, some bright EUV loops must be preceded by bright X-ray loops. Previous analysis of X-ray and EUV active region observations, however, have concluded that EUV loops are not preceded by X-ray loops. In...

Global Properties of M31's Stellar Halo from the SPLASH Survey. I. Surface Brightness Profile

Science.gov (United States)

Gilbert, Karoline M.; Guhathakurta, Puragra; Beaton, Rachael L.; Bullock, James; Geha, Marla C.; Kalirai, Jason S.; Kirby, Evan N.; Majewski, Steven R.; Ostheimer, James C.; Patterson, Richard J.; Tollerud, Erik J.; Tanaka, Mikito; Chiba, Masashi

2012-11-01

We present the surface brightness profile of M31's stellar halo out to a projected radius of 175 kpc. The surface brightness estimates are based on confirmed samples of M31 red giant branch stars derived from Keck/DEIMOS spectroscopic observations. A set of empirical spectroscopic and photometric M31 membership diagnostics is used to identify and reject foreground and background contaminants. This enables us to trace the stellar halo of M31 to larger projected distances and fainter surface brightnesses than previous photometric studies. The surface brightness profile of M31's halo follows a power law with index -2.2 ± 0.2 and extends to a projected distance of at least ~175 kpc (~2/3 of M31's virial radius), with no evidence of a downward break at large radii. The best-fit elliptical isophotes have b/a = 0.94 with the major axis of the halo aligned along the minor axis of M31's disk, consistent with a prolate halo, although the data are also consistent with M31's halo having spherical symmetry. The fact that tidal debris features are kinematically cold is used to identify substructure in the spectroscopic fields out to projected radii of 90 kpc and investigate the effect of this substructure on the surface brightness profile. The scatter in the surface brightness profile is reduced when kinematically identified tidal debris features in M31 are statistically subtracted; the remaining profile indicates that a comparatively diffuse stellar component to M31's stellar halo exists to large distances. Beyond 90 kpc, kinematically cold tidal debris features cannot be identified due to small number statistics; nevertheless, the significant field-to-field variation in surface brightness beyond 90 kpc suggests that the outermost region of M31's halo is also comprised to a significant degree of stars stripped from accreted objects. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California

Variation reduction of brightness and pH of pulp sent to a paper mill

Directory of Open Access Journals (Sweden)

Napassavong Rojanarowan

2015-03-01

Full Text Available The variance of the brightness of pulp sent to the paper mill during the changing period of dry pulp grades affects the chemical control in the paper mill. This research aims to determine the mixing formula of pulp with different brightness from the EOP and D1 stages to handle this variation issue. This research uses response surface design with Central Composite Design type, regression technique and optimization technique to find the optimal setting of the mixing formula for each of the seven brightness levels to obtain the target brightness of 86% and the pH of 5.25. The mixing formulas are determined by the pulp mixing percentage and the sulfuric acid consumption. The experimental results reveal that when using higher EOP mixing ratio, the brightness decreases and the pH increases. Regarding the effect of the sulfuric acid, increasing the sulfuric acid makes the brightness and the pH decrease. After implementing the optimal formula in the production line, the mean of pulp brightness is closer to the target compared with the brightness before improvement and the brightness variation decreases without affecting the quality of other pulp grades, average of brightness decreased from 87.4% to 86.3% and standard deviation of brightness decreased from 1.09 to 0.46.

Brightness of synchrotron radiation from wigglers

International Nuclear Information System (INIS)

Geloni, Gianluca; Kocharyan, Vitali; Saldin, Evgeni

2014-12-01

According to literature, while calculating the brightness of synchrotron radiation from wigglers, one needs to account for the so called 'depth-of-field' effects. In fact, the particle beam cross section varies along the wiggler. It is usually stated that the effective photon source size increases accordingly, while the brightness is reduced. Here we claim that this is a misconception originating from an analysis of the wiggler source based on geometrical arguments, regarded as almost self-evident. According to electrodynamics, depth-of-field effects do not exist: we demonstrate this statement both theoretically and numerically, using a well-known first-principle computer code. This fact shows that under the usually accepted approximations, the description of the wiggler brightness turns out to be inconsistent even qualitatively. Therefore, there is a need for a well-defined procedure for computing the brightness from a wiggler source. We accomplish this task based on the use of a Wigner function formalism. In the geometrical optics limit computations can be performed analytically. Within this limit, we restrict ourselves to the case of the beam size-dominated regime, which is typical for synchrotron radiation facilities in the X-ray wavelength range. We give a direct demonstration of the fact that the apparent horizontal source size is broadened in proportion to the beamline opening angle and to the length of the wiggler. While this effect is well-understood, a direct proof appears not to have been given elsewhere. We consider the problem of the calculation of the wiggler source size by means of numerical simulations alone, which play the same role of an experiment. We report a significant numerical disagreement between exact calculations and approximations currently used in literature.

High brightness ion source

International Nuclear Information System (INIS)

Dreyfus, R.W.; Hodgson, R.T.

1975-01-01

A high brightness ion beam is obtainable by using lasers to excite atoms or molecules from the ground state to an ionized state in increments, rather than in one step. The spectroscopic resonances of the atom or molecule are used so that relatively long wavelength, low power lasers can be used to obtain such ion beam

The bright and dark side of cooperation for regional innovation performance

OpenAIRE

Broekel, Tom; Meder, Andreas

2008-01-01

Studies analyzing the importance of intra- and inter-regional cooperation for regional innovation performance are mainly of qualitative nature and focus strongly on the positive effects that high levels of cooperation can yield. For the case of the German labor market regions and the Electrics + Electronics industry the paper provides a quantitative-empirical analysis taking into account the possibility of negative effects related to regional lock-in, lock-out, and cooperation overload situat...

The behavior of the 3.28 μm dust feature in NGC 2024

International Nuclear Information System (INIS)

Brand, P.W.J.L.; Meadows, P.J.; Wolstencroft, R.D.

1984-01-01

Observations of the 3.28 μm unidentified dust emission feature and the hydrogen Brackett alpha line have been made at several spatial positions across the ionization front in the HII region NGC 2024. The hydrogen observations delineate the edge of the ionised region while the 3.3 μm feature is seen to be continuous across the front. The 3.4 μm feature is observed with a constant strength relative to the 3.28 μm feature of 0.3 +- 0.1. Since the 3.28 μm feature is seen outside the ionized region the dust has to be excited by non-ionizing ultra-violet photons from the exciting star in the HII region. (author)

Hi-C Observations of Penumbral Bright Dots

Science.gov (United States)

Alpert, S. E.; Tiwari, S. K.; Moore, R. L.; Savage, S. L.; Winebarger, A. R.

2014-01-01

We use high-quality data obtained by the High Resolution Coronal Imager (Hi-C) to examine bright dots (BDs) in a sunspot's penumbra. The sizes of these BDs are on the order of 1 arcsecond (1") and are therefore hard to identify using the Atmospheric Imaging Assembly's (AIA) 0.6" pixel(exp -1) resolution. These BD become readily apparent with Hi-C's 0.1" pixel(exp -1) resolution. Tian et al. (2014) found penumbral BDs in the transition region (TR) by using the Interface Region Imaging Spectrograph (IRIS). However, only a few of their dots could be associated with any enhanced brightness in AIA channels. In this work, we examine the characteristics of the penumbral BDs observed by Hi-C in a sunspot penumbra, including their sizes, lifetimes, speeds, and intensity. We also attempt to find any association of these BDs to the IRIS BDs. There are fewer Hi-C BDs in the penumbra than seen by IRIS, though different sunspots were studied. We use 193 Angstroms Hi-C data from July 11, 2012 which observed from approximately 18:52:00 UT- 18:56:00 UT and supplement it with data from AIA's 193 Angstrom passband to see the complete lifetime of the dots that were born before and/or lasted longer than Hi- C's 5-minute observation period. We use additional AIA passbands and compare the light curves of the BDs at different temperatures to test whether the Hi-C BDs are TR BDs. We find that most Hi-C BDs show clear movement, and of those that do, they move in a radial direction, toward or away from the sunspot umbra. Single BDs interact with other BDs, combining to fade away or brighten. The BDs that do not interact with other BDs tend to move less. Many of the properties of our BDs are similar to the extreme values of the IRIS BDs, e.g., they move slower on average and their sizes and lifetimes are on the higher end of the IRIS BDs. We infer that our penumbral BDs are the large-scale end of the distribution of BDs observed by IRIS.

Brightness-normalized Partial Least Squares Regression for hyperspectral data

International Nuclear Information System (INIS)

Feilhauer, Hannes; Asner, Gregory P.; Martin, Roberta E.; Schmidtlein, Sebastian

2010-01-01

Developed in the field of chemometrics, Partial Least Squares Regression (PLSR) has become an established technique in vegetation remote sensing. PLSR was primarily designed for laboratory analysis of prepared material samples. Under field conditions in vegetation remote sensing, the performance of the technique may be negatively affected by differences in brightness due to amount and orientation of plant tissues in canopies or the observing conditions. To minimize these effects, we introduced brightness normalization to the PLSR approach and tested whether this modification improves the performance under changing canopy and observing conditions. This test was carried out using high-fidelity spectral data (400-2510 nm) to model observed leaf chemistry. The spectral data was combined with a canopy radiative transfer model to simulate effects of varying canopy structure and viewing geometry. Brightness normalization enhanced the performance of PLSR by dampening the effects of canopy shade, thus providing a significant improvement in predictions of leaf chemistry (up to 3.6% additional explained variance in validation) compared to conventional PLSR. Little improvement was made on effects due to variable leaf area index, while minor improvement (mostly not significant) was observed for effects of variable viewing geometry. In general, brightness normalization increased the stability of model fits and regression coefficients for all canopy scenarios. Brightness-normalized PLSR is thus a promising approach for application on airborne and space-based imaging spectrometer data.

T1 bright appendix sign to exclude acute appendicitis in pregnant women

International Nuclear Information System (INIS)

Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun

2017-01-01

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. (orig.)

T1 bright appendix sign to exclude acute appendicitis in pregnant women

Energy Technology Data Exchange (ETDEWEB)

Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun [Yonsei University College of Medicine, Department of Radiology, Research Institute of Radiological Science, Severance Hospital, 50-1 Yonsei-ro, Seodaemun-gu, Seoul (Korea, Republic of)

2017-08-15

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. (orig.)

Quantitative measurement of brightness from living cells in the presence of photodepletion.

Directory of Open Access Journals (Sweden)

Kwang-Ho Hur

Full Text Available The brightness of fluorescently labeled proteins provides an excellent marker for identifying protein interactions in living cells. Quantitative interpretation of brightness, however, hinges on a detailed understanding of the processes that affect the signal fluctuation of the fluorescent label. Here, we focus on the cumulative influence of photobleaching on brightness measurements in cells. Photobleaching within the finite volume of the cell leads to a depletion of the population of fluorescently labeled proteins with time. The process of photodepletion reduces the fluorescence signal which biases the analysis of brightness data. Our data show that even small reductions in the signal can introduce significant bias into the analysis of the data. We develop a model that quantifies the bias and introduce an analysis method that accurately determines brightness in the presence of photodepletion as verified by experiments with mammalian and yeast cells. In addition, photodepletion experiments with the fluorescent protein EGFP reveal the presence of a photoconversion process, which leads to a marked decrease in the brightness of the EGFP protein. We also identify conditions where the effect of EGFP's photoconversion on brightness experiments can be safely ignored.

Dark and bright solitons in a quasi-one-dimensional Bose-Einstein condensate

International Nuclear Information System (INIS)

Wang, Shun-Jin; Jia, Cheng-Long; An, Jun-Hong; Zhao, Dun; Luo, Hong-Gang

2003-01-01

The analytical dark and bright soliton solutions of the one-dimensional Gross-Pitaevskii equation with a confining potential are obtained. For the bright soliton, the recent experimental finding is studied, and the particle number of the soliton and the window of the particle numbers for the bright soliton to occur are estimated analytically and in good agreement with the experimental data. The existence of dark soliton for the attractive interaction and bright soliton for the repulsive interaction is predicted under proper conditions

Quadrature measurements of a bright squeezed state via sideband swapping

DEFF Research Database (Denmark)

Schneider, J.; Glockl, O.; Leuchs, G.

2009-01-01

The measurement of an arbitrary quadrature of a bright quantum state of light is a commonly requested action in many quantum information protocols, but it is experimentally challenging with previously proposed schemes. We suggest that the quadrature be measured at a specific sideband frequency...... of a bright quantum state by transferring the sideband modes under interrogation to a vacuum state and subsequently measuring the quadrature via homodyne detection. The scheme is implemented experimentally, and it is successfully tested with a bright squeezed state of light....

Bright circularly polarized soft X-ray high harmonics for X-ray magnetic circular dichroism.

Science.gov (United States)

Fan, Tingting; Grychtol, Patrik; Knut, Ronny; Hernández-García, Carlos; Hickstein, Daniel D; Zusin, Dmitriy; Gentry, Christian; Dollar, Franklin J; Mancuso, Christopher A; Hogle, Craig W; Kfir, Ofer; Legut, Dominik; Carva, Karel; Ellis, Jennifer L; Dorney, Kevin M; Chen, Cong; Shpyrko, Oleg G; Fullerton, Eric E; Cohen, Oren; Oppeneer, Peter M; Milošević, Dejan B; Becker, Andreas; Jaroń-Becker, Agnieszka A; Popmintchev, Tenio; Murnane, Margaret M; Kapteyn, Henry C

2015-11-17

We demonstrate, to our knowledge, the first bright circularly polarized high-harmonic beams in the soft X-ray region of the electromagnetic spectrum, and use them to implement X-ray magnetic circular dichroism measurements in a tabletop-scale setup. Using counterrotating circularly polarized laser fields at 1.3 and 0.79 µm, we generate circularly polarized harmonics with photon energies exceeding 160 eV. The harmonic spectra emerge as a sequence of closely spaced pairs of left and right circularly polarized peaks, with energies determined by conservation of energy and spin angular momentum. We explain the single-atom and macroscopic physics by identifying the dominant electron quantum trajectories and optimal phase-matching conditions. The first advanced phase-matched propagation simulations for circularly polarized harmonics reveal the influence of the finite phase-matching temporal window on the spectrum, as well as the unique polarization-shaped attosecond pulse train. Finally, we use, to our knowledge, the first tabletop X-ray magnetic circular dichroism measurements at the N4,5 absorption edges of Gd to validate the high degree of circularity, brightness, and stability of this light source. These results demonstrate the feasibility of manipulating the polarization, spectrum, and temporal shape of high harmonics in the soft X-ray region by manipulating the driving laser waveform.

SKYMONITOR: A Global Network for Sky Brightness Measurements

Science.gov (United States)

Davis, Donald R.; Mckenna, D.; Pulvermacher, R.; Everett, M.

2010-01-01

We are implementing a global network to measure sky brightness at dark-sky critical sites with the goal of creating a multi-decade database. The heart of this project is the Night Sky Brightness Monitor (NSBM), an autonomous 2 channel photometer which measures night sky brightness in the visual wavelengths (Mckenna et al, AAS 2009). Sky brightness is measured every minute at two elevation angles typically zenith and 20 degrees to monitor brightness and transparency. The NSBM consists of two parts, a remote unit and a base station with an internet connection. Currently these devices use 2.4 Ghz transceivers with a range of 100 meters. The remote unit is battery powered with daytime recharging using a solar panel. Data received by the base unit is transmitted via email protocol to IDA offices in Tucson where it will be collected, archived and made available to the user community via a web interface. Two other versions of the NSBM are under development: one for radio sensitive areas using an optical fiber link and the second that reads data directly to a laptop for sites without internet access. NSBM units are currently undergoing field testing at two observatories. With support from the National Science Foundation, we will construct and install a total of 10 units at astronomical observatories. With additional funding, we will locate additional units at other sites such as National Parks, dark-sky preserves and other sites where dark sky preservation is crucial. We will present the current comparison with the National Park Service sky monitoring camera. We anticipate that the SKYMONITOR network will be functioning by the end of 2010.

Circulating CD14brightCD16+ 'intermediate' monocytes exhibit enhanced parasite pattern recognition in human helminth infection.

Directory of Open Access Journals (Sweden)

Joseph D Turner

2014-04-01

Full Text Available Circulating monocyte sub-sets have recently emerged as mediators of divergent immune functions during infectious disease but their role in helminth infection has not been investigated. In this study we evaluated whether 'classical' (CD14brightCD16-, 'intermediate' (CD14brightCD16+, and 'non-classical' (CD14dimCD16+ monocyte sub-sets from peripheral blood mononuclear cells varied in both abundance and ability to bind antigenic material amongst individuals living in a region of Northern Senegal which is co-endemic for Schistosoma mansoni and S. haematobium. Monocyte recognition of excretory/secretory (E/S products released by skin-invasive cercariae, or eggs, of S. mansoni was assessed by flow cytometry and compared between S. mansoni mono-infected, S. mansoni and S. haematobium co-infected, and uninfected participants. Each of the three monocyte sub-sets in the different infection groups bound schistosome E/S material. However, 'intermediate' CD14brightCD16+ monocytes had a significantly enhanced ability to bind cercarial and egg E/S. Moreover, this elevation of ligand binding was particularly evident in co-infected participants. This is the first demonstration of modulated parasite pattern recognition in CD14brightCD16+ intermediate monocytes during helminth infection, which may have functional consequences for the ability of infected individuals to respond immunologically to infection.

A surface brightness analysis of eight RR Lyrae stars

International Nuclear Information System (INIS)

Hawley, S.L.; Barnes, T.G. III; Moffett, T.J.

1987-01-01

The authors have used a surface brightness, (V-R) relation to analyze new contemporaneous photometry and radial velocity data for 6 RR-ab type stars and to re-analyze previously published data for RR Lyrae and X Arietis. Systematic effects were found in the surface brightness at phases near minimum radius. Excluding these phases, they determine the slope of the surface brightness relation and the mean radius for each star. They also find a zero point which includes both a distance term and the zero point of the surface brightness relation. The sample includes stars with Preston's metallicity indicator ΔS = 0 to 9, with periods ranging from 0.397 days to 0.651 days. Their results indicate a log(R/R solar ) vs. log P relation in the sense that stars with longer periods have larger radii, in agreement with theoretical predictions. Their radii are consistent with bolometric magnitudes in the range 0.2 - 0.8 magnitude but accurate magnitudes must await a reliable T e - color calibration

Solar brightness distribution at 8.6 mm from interferometer observations

International Nuclear Information System (INIS)

Kawabata, K.; Fujishita, M.; Kato, T.; Ogawa, H.; Omodaka, T.

1980-01-01

The radial brightness distribution of the quiet Sun at 8.6 mm is synthesized from observations using a sixteen element east-west interferometer in Nagoya. The observed brightness is flat from the disk center to 0.8 Rsub(sun). A slight darkening appeared between 0.8 Rsub(sun) and the limb. No evidence if the bright ring near the limb is found. The radio radius at 8.6 mm is 1.015 +- 0.005 Rsub(sun). In addition there exists a coronal component just outside the radio limb. (orig.)

Cross-dimensional mapping of number, length and brightness by preschool children.

Directory of Open Access Journals (Sweden)

Maria Dolores de Hevia

Full Text Available Human adults in diverse cultures, children, infants, and non-human primates relate number to space, but it is not clear whether this ability reflects a specific and privileged number-space mapping. To investigate this possibility, we tested preschool children in matching tasks where the dimensions of number and length were mapped both to one another and to a third dimension, brightness. Children detected variation on all three dimensions, and they reliably performed mappings between number and length, and partially between brightness and length, but not between number and brightness. Moreover, children showed reliably better mapping of number onto the dimension of length than onto the dimension of brightness. These findings suggest that number establishes a privileged mapping with the dimension of length, and that other dimensions, including brightness, can be mapped onto length, although less efficiently. Children's adeptness at number-length mappings suggests that these two dimensions are intuitively related by the end of the preschool years.

T1 bright appendix sign to exclude acute appendicitis in pregnant women.

Science.gov (United States)

Shin, Ilah; An, Chansik; Lim, Joon Seok; Kim, Myeong-Jin; Chung, Yong Eun

2017-08-01

To evaluate the diagnostic value of the T1 bright appendix sign for the diagnosis of acute appendicitis in pregnant women. This retrospective study included 125 pregnant women with suspected appendicitis who underwent magnetic resonance (MR) imaging. The T1 bright appendix sign was defined as a high intensity signal filling more than half length of the appendix on T1-weighted imaging. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the T1 bright appendix sign for normal appendix identification were calculated in all patients and in those with borderline-sized appendices (6-7 mm). The T1 bright appendix sign was seen in 51% of patients with normal appendices, but only in 4.5% of patients with acute appendicitis. The overall sensitivity, specificity, PPV, and NPV of the T1 bright appendix sign for normal appendix diagnosis were 44.9%, 95.5%, 97.6%, and 30.0%, respectively. All four patients with borderline sized appendix with appendicitis showed negative T1 bright appendix sign. The T1 bright appendix sign is a specific finding for the diagnosis of a normal appendix in pregnant women with suspected acute appendicitis. • Magnetic resonance imaging is increasingly used in emergency settings. • Acute appendicitis is the most common cause of acute abdomen. • Magnetic resonance imaging is widely used in pregnant population. • T1 bright appendix sign can be a specific sign representing normal appendix.

State-Of High Brightness RF Photo-Injector Design

Science.gov (United States)

Ferrario, Massimo; Clendenin, Jym; Palmer, Dennis; Rosenzweig, James; Serafini, Luca

2000-04-01

The art of designing optimized high brightness electron RF Photo-Injectors has moved in the last decade from a cut and try procedure, guided by experimental experience and time consuming particle tracking simulations, up to a fast parameter space scanning, guided by recent analytical results and a fast running semi-analytical code, so to reach the optimum operating point which corresponds to maximum beam brightness. Scaling laws and the theory of invariant envelope provide to the designers excellent tools for a first parameters choice and the code HOMDYN, based on a multi-slice envelope description of the beam dynamics, is tailored to describe the space charge dominated dynamics of laminar beams in presence of time dependent space charge forces, giving rise to a very fast modeling capability for photo-injectors design. We report in this talk the results of a recent beam dynamics study, motivated by the need to redesign the LCLS photoinjector. During this work a new effective working point for a split RF photoinjector has been discovered by means of the previous mentioned approach. By a proper choice of rf gun and solenoid parameters, the emittance evolution shows a double minimum behavior in the drifting region. If the booster is located where the relative emittance maximum and the envelope waist occur, the second emittance minimum can be shifted at the booster exit and frozen at a very low level (0.3 mm-mrad for a 1 nC flat top bunch), to the extent that the invariant envelope matching conditions are satisfied.

Characterizing the Motion of Solar Magnetic Bright Points at High Resolution

Science.gov (United States)

Van Kooten, Samuel J.; Cranmer, Steven R.

2017-11-01

Magnetic bright points in the solar photosphere, visible in both continuum and G-band images, indicate footpoints of kilogauss magnetic flux tubes extending to the corona. The power spectrum of bright-point motion is thus also the power spectrum of Alfvén wave excitation, transporting energy up flux tubes into the corona. This spectrum is a key input in coronal and heliospheric models. We produce a power spectrum of bright-point motion using radiative magnetohydrodynamic simulations, exploiting spatial resolution higher than can be obtained in present-day observations, while using automated tracking to produce large data quantities. We find slightly higher amounts of power at all frequencies compared to observation-based spectra, while confirming the spectrum shape of recent observations. This also provides a prediction for observations of bright points with DKIST, which will achieve similar resolution and high sensitivity. We also find a granule size distribution in support of an observed two-population distribution, and we present results from tracking passive tracers, which show a similar power spectrum to that of bright points. Finally, we introduce a simplified, laminar model of granulation, with which we explore the roles of turbulence and of the properties of the granulation pattern in determining bright-point motion.

Exploiting the synergy between SMAP and SMOS to improve brightness temperature simulations and soil moisture retrievals in arid regions

Science.gov (United States)

Ebrahimi, Mohsen; Alavipanah, Seyed Kazem; Hamzeh, Saeid; Amiraslani, Farshad; Neysani Samany, Najmeh; Wigneron, Jean-Pierre

2018-02-01

The objective of this study was to exploit the synergy between SMOS and SMAP based on vegetation optical depth (VOD) to improve brightness temperature (TB) simulations and land surface soil moisture (SM) retrievals in arid regions of the world. In the current operational algorithm of SMAP (level 2), vegetation water content (VWC) is considered as a proxy to compute VOD which is calculated by an empirical conversion function of NDVI. Avoiding the empirical estimation of VOD, the SMOS algorithm is used to retrieve simultaneously SM and VOD from TB observations. The present study attempted to improve SMAP TB simulations and SM retrievals by benefiting from the advantages of the SMOS (L-MEB) algorithm. This was achieved by using a synergy method based on replacing the default value of SMAP VOD with the retrieved value of VOD from the SMOS multi angular and bi-polarization observations of TB. The insitu SM measurements, used as reference SM in this study, were obtained from the International Soil Moisture Network (ISMN) over 180 stations located in arid regions of the world. Furthermore, four stations were randomly selected to analyze the temporal variations in VOD and SM. Results of the synergy method showed that the accuracy of the TB simulations and SM retrievals was respectively improved at 144 and 124 stations (out of a total of 180 stations) in terms of coefficient of determination (R2) and unbiased root mean squared error (UbRMSE). Analyzing the temporal variations in VOD showed that the SMOS VOD, conversely to the SMAP VOD, can better illustrate the presence of herbaceous plants and may be a better indicator of the seasonal changes in the vegetation density and biomass over the year.

Bright-Dark Mixed N-Soliton Solutions of the Multi-Component Mel'nikov System

Science.gov (United States)

Han, Zhong; Chen, Yong; Chen, Junchao

2017-10-01

By virtue of the Kadomtsev-Petviashvili (KP) hierarchy reduction technique, we construct the general bright-dark mixed N-soliton solution to the multi-component Mel'nikov system. This multi-component system comprised of multiple (say M) short-wave components and one long-wave component with all possible combinations of nonlinearities including all-positive, all-negative and mixed types. Firstly, the two-bright-one-dark (2-b-1-d) and one-bright-two-dark (1-b-2-d) mixed N-soliton solutions in short-wave components of the three-component Mel'nikov system are derived in detail. Then we extend our analysis to the M-component Mel'nikov system to obtain its general mixed N-soliton solution. The formula obtained unifies the all-bright, all-dark and bright-dark mixed N-soliton solutions. For the collision of two solitons, an asymptotic analysis shows that for an M-component Mel'nikov system with M ≥ 3, inelastic collision takes place, resulting in energy exchange among the short-wave components supporting bright solitons only if the bright solitons appear in at least two short-wave components. In contrast, the dark solitons in the short-wave components and the bright solitons in the long-wave component always undergo elastic collision which is only accompanied by a position shift.

Optical observations of the nearby galaxy IC342 with narrow band [SII] and Hα filters. I

Directory of Open Access Journals (Sweden)

Vučetić M.M.

2013-01-01

Full Text Available We present observations of a portion of the nearby spiral galaxy IC342 using narrow band [SII] and Hα filters. These observations were carried out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical Observatory in Bulgaria. In this paper we report coordinates, diameters, Hα and [SII] fluxes for 203 HII regions detected in two fields of view in IC342 galaxy. The number of detected HII regions is 5 times higher than previously known in these two parts of the galaxy. [Projekat Ministarstva nauke Republike Srbije, br. 176005: Emission nebulae: structure and evolution

Bright light in elderly subjects with nonseasonal major depressive disorder: a double blind randomised clinical trial using early morning bright blue light comparing dim red light treatment

Directory of Open Access Journals (Sweden)

van Someren Eus JW

2008-07-01

Full Text Available Abstract Background Depression frequently occurs in the elderly. Its cause is largely unknown, but several studies point to disturbances of biological rhythmicity. In both normal aging, and depression, the functioning of the suprachiasmatic nucleus (SCN is impaired, as evidenced by an increased prevalence of day-night rhythm perturbations, such as sleeping disorders. Moreover, the inhibitory SCN neurons on the hypothalamus-pituitary adrenocortical axis (HPA-axis have decreased activity and HPA-activity is enhanced, when compared to non-depressed elderly. Using bright light therapy (BLT the SCN can be stimulated. In addition, the beneficial effects of BLT on seasonal depression are well accepted. BLT is a potentially safe, nonexpensive and well accepted treatment option. But the current literature on BLT for depression is inconclusive. Methods/Design This study aims to show whether BLT can reduce non-seasonal major depression in elderly patients. Randomized double blind placebo controlled trial in 126 subjects of 60 years and older with a diagnosis of major depressive disorder (MDD, DSM-IV/SCID-I. Subjects are recruited through referrals of psychiatric outpatient clinics and from case finding from databases of general practitioners and old-people homes in the Amsterdam region. After inclusion subjects are randomly allocated to the active (bright blue light vs. placebo (dim red light condition using two Philips Bright Light Energy boxes type HF 3304 per subject, from which the light bulbs have been covered with bright blue- or dim red light- permitting filters. Patients will be stratified by use of antidepressants. Prior to treatment a one-week period without light treatment will be used. At three time points several endocrinological, psychophysiological, psychometrically, neuropsychological measures are performed: just before the start of light therapy, after completion of three weeks therapy period, and three weeks thereafter. Discussion If BLT

Diode lasers optimized in brightness for fiber laser pumping

Science.gov (United States)

Kelemen, M.; Gilly, J.; Friedmann, P.; Hilzensauer, S.; Ogrodowski, L.; Kissel, H.; Biesenbach, J.

2018-02-01

In diode laser applications for fiber laser pumping and fiber-coupled direct diode laser systems high brightness becomes essential in the last years. Fiber coupled modules benefit from continuous improvements of high-power diode lasers on chip level regarding output power, efficiency and beam characteristics resulting in record highbrightness values and increased pump power. To gain high brightness not only output power must be increased, but also near field widths and far field angles have to be below a certain value for higher power levels because brightness is proportional to output power divided by beam quality. While fast axis far fields typically show a current independent behaviour, for broadarea lasers far-fields in the slow axis suffer from a strong current and temperature dependence, limiting the brightness and therefore their use in fibre coupled modules. These limitations can be overcome by carefully optimizing chip temperature, thermal lensing and lateral mode structure by epitaxial and lateral resonator designs and processing. We present our latest results for InGaAs/AlGaAs broad-area single emitters with resonator lengths of 4mm emitting at 976nm and illustrate the improvements in beam quality over the last years. By optimizing the diode laser design a record value of the brightness for broad-area lasers with 4mm resonator length of 126 MW/cm2sr has been demonstrated with a maximum wall-plug efficiency of more than 70%. From these design also pump modules based on 9 mini-bars consisting of 5 emitters each have been realized with 360W pump power.

Progress in extremely high brightness LED-based light sources

Science.gov (United States)

Hoelen, Christoph; Antonis, Piet; de Boer, Dick; Koole, Rolf; Kadijk, Simon; Li, Yun; Vanbroekhoven, Vincent; Van De Voorde, Patrick

2017-09-01

Although the maximum brightness of LEDs has been increasing continuously during the past decade, their luminance is still far from what is required for multiple applications that still rely on the high brightness of discharge lamps. In particular for high brightness applications with limited étendue, e.g. front projection, only very modest luminance values in the beam can be achieved with LEDs compared to systems based on discharge lamps or lasers. With dedicated architectures, phosphor-converted green LEDs for projection may achieve luminance values up to 200-300 Mnit. In this paper we report on the progress made in the development of light engines based on an elongated luminescent concentrator pumped by blue LEDs. This concept has recently been introduced to the market as ColorSpark High Lumen Density LED technology. These sources outperform the maximum brightness of LEDs by multiple factors. In LED front projection, green LEDs are the main limiting factor. With our green modules, we now have achieved peak luminance values of 2 Gnit, enabling LED-based projection systems with over 4000 ANSI lm. Extension of this concept to yellow and red light sources is presented. The light source efficiency has been increased considerably, reaching 45-60 lm/W for green under practical application conditions. The module architecture, beam shaping, and performance characteristics are reviewed, as well as system aspects. The performance increase, spectral range extensions, beam-shaping flexibility, and cost reductions realized with the new module architecture enable a breakthrough in LED-based projection systems and in a wide variety of other high brightness applications.

Afternoon nap and bright light exposure improve cognitive flexibility post lunch.

Directory of Open Access Journals (Sweden)

Hichem Slama

Full Text Available Beneficial effects of napping or bright light exposure on cognitive performance have been reported in participants exposed to sleep loss. Nonetheless, few studies investigated the effect of these potential countermeasures against the temporary drop in performance observed in mid-afternoon, and even less so on cognitive flexibility, a crucial component of executive functions. This study investigated the impact of either an afternoon nap or bright light exposure on post-prandial alterations in task switching performance in well-rested participants. Twenty-five healthy adults participated in two randomized experimental conditions, either wake versus nap (n=15, or bright light versus placebo (n=10. Participants were tested on a switching task three times (morning, post-lunch and late afternoon sessions. The interventions occurred prior to the post-lunch session. In the nap/wake condition, participants either stayed awake watching a 30-minute documentary or had the opportunity to take a nap for 30 minutes. In the bright light/placebo condition, participants watched a documentary under either bright blue light or dim orange light (placebo for 30 minutes. The switch cost estimates cognitive flexibility and measures task-switching efficiency. Increased switch cost scores indicate higher difficulties to switch between tasks. In both control conditions (wake or placebo, accuracy switch-cost score increased post lunch. Both interventions (nap or bright light elicited a decrease in accuracy switch-cost score post lunch, which was associated with diminished fatigue and decreased variability in vigilance. Additionally, there was a trend for a post-lunch benefit of bright light with a decreased latency switch-cost score. In the nap group, improvements in accuracy switch-cost score were associated with more NREM sleep stage N1. Thus, exposure to bright light during the post-lunch dip, a countermeasure easily applicable in daily life, results in similar

Analysis of Bright Harvest Remote Analysis for Residential Solar Installations

Energy Technology Data Exchange (ETDEWEB)

Nangle, John [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simon, Joseph [National Renewable Energy Lab. (NREL), Golden, CO (United States)

2015-06-17

Bright Harvest provides remote shading analysis and design products for residential PV system installers. The National Renewable Energy Laboratory (NREL) through the NREL Commercialization Assistance Program, completed comparative assessments between on-site measurements and remotely calculated values to validate the accuracy of Bright Harvest’s remote shading and power generation.

Inferring Land Surface Model Parameters for the Assimilation of Satellite-Based L-Band Brightness Temperature Observations into a Soil Moisture Analysis System

Science.gov (United States)

Reichle, Rolf H.; De Lannoy, Gabrielle J. M.

2012-01-01

The Soil Moisture and Ocean Salinity (SMOS) satellite mission provides global measurements of L-band brightness temperatures at horizontal and vertical polarization and a variety of incidence angles that are sensitive to moisture and temperature conditions in the top few centimeters of the soil. These L-band observations can therefore be assimilated into a land surface model to obtain surface and root zone soil moisture estimates. As part of the observation operator, such an assimilation system requires a radiative transfer model (RTM) that converts geophysical fields (including soil moisture and soil temperature) into modeled L-band brightness temperatures. At the global scale, the RTM parameters and the climatological soil moisture conditions are still poorly known. Using look-up tables from the literature to estimate the RTM parameters usually results in modeled L-band brightness temperatures that are strongly biased against the SMOS observations, with biases varying regionally and seasonally. Such biases must be addressed within the land data assimilation system. In this presentation, the estimation of the RTM parameters is discussed for the NASA GEOS-5 land data assimilation system, which is based on the ensemble Kalman filter (EnKF) and the Catchment land surface model. In the GEOS-5 land data assimilation system, soil moisture and brightness temperature biases are addressed in three stages. First, the global soil properties and soil hydraulic parameters that are used in the Catchment model were revised to minimize the bias in the modeled soil moisture, as verified against available in situ soil moisture measurements. Second, key parameters of the "tau-omega" RTM were calibrated prior to data assimilation using an objective function that minimizes the climatological differences between the modeled L-band brightness temperatures and the corresponding SMOS observations. Calibrated parameters include soil roughness parameters, vegetation structure parameters

Dark and bright vortex solitons in electromagnetically induced transparent media

International Nuclear Information System (INIS)

Wu Xuan; Xie Xiaotao; Yang Xiaoxue

2006-01-01

We show that dark and bright vortex solitons can exist in three-state electromagnetically induced transparent media under some appropriate conditions. We also analyse the stability of the dark and bright vortex solitons. This work may provide other research opportunities in nonlinear optical experiments and may result in a substantial impact on technology

SKY BRIGHTNESS AND TRANSPARENCY IN THE i-BAND AT DOME A, ANTARCTICA

International Nuclear Information System (INIS)

Zou Hu; Zhou Xu; Jiang Zhaoji; Hu Jingyao; Ma Jun; Ashley, M. C. B.; Luong-Van, D. M.; Storey, J. W. V.; Cui Xiangqun; Feng Longlong; Gong Xuefei; Kulesa, C. A.; Lawrence, J. S.; Liu Genrong; Moore, A. M.; Pennypacker, C. R.; Travouillon, T.; Qin Weijia; Sun Bo; Shang Zhaohui

2010-01-01

The i-band observing conditions at Dome A on the Antarctic plateau have been investigated using data acquired during 2008 with the Chinese Small Telescope Array. The sky brightness, variations in atmospheric transparency, cloud cover, and the presence of aurorae are obtained from these images. The median sky brightness of moonless clear nights is 20.5 mag arcsec -2 in the SDSS i band at the south celestial pole (which includes a contribution of about 0.06 mag from diffuse Galactic light). The median over all Moon phases in the Antarctic winter is about 19.8 mag arcsec -2 . There were no thick clouds in 2008. We model contributions of the Sun and the Moon to the sky background to obtain the relationship between the sky brightness and transparency. Aurorae are identified by comparing the observed sky brightness to the sky brightness expected from this model. About 2% of the images are affected by relatively strong aurorae.

Leonids 2017 from Norway – A bright surprise!

Science.gov (United States)

Gaarder, K.

2018-01-01

I am very pleased to have been able to observe near maximum activity of the Leonids, and clearly witnessed the unequal mass distribution during these hours. A lot of bright Leonids were seen, followed by a short period of high activity of fainter meteors, before a sharp drop in activity. The Leonids is undoubtedly a shower to watch closely, with its many variations in activity level and magnitude distribution. I already look forward to observing the next years’ display, hopefully under a dark and clear sky, filled with bright meteors!

Low-Surface-Brightness Galaxies: Hidden Galaxies Revealed

Science.gov (United States)

Bothun, G.; Impey, C.; McGaugh, S.

1997-07-01

In twenty years, low surface brightness (LSB) galaxies have evolved from being an idiosyncratic notion to being one of the major baryonic repositories in the Universe. The story of their discovery and the characterization of their properties is told here. Their recovery from the noise of the night sky background is a strong testament to the severity of surface brightness selection effects. LSB galaxies have a number of remarkable properties which distinguish them from the more familiar Hubble Sequence of spirals. The two most important are 1) they evolve at a significantly slower rate and may well experience star formation outside of the molecular cloud environment, 2) they are embedded in dark matter halos which are of lower density and more extended than the halos around high surface brightness (HSB) disk galaxies. Compared to HSB disks, LSB disks are strongly dark matter dominated at all radii and show a systematic increase in $M/L$ with decreasing central surface brightness. In addition, the recognition that large numbers of LSB galaxies actually exist has changed the form of the galaxy luminosity function and has clearly increased the space density of galaxies at z =0. Recent CCD surveys have uncovered a population of red LSB disks that may be related to the excess of faint blue galaxies detected at moderate redshifts. LSB galaxies offer us a new window into galaxy evolution and formation which is every bit as important as those processes which have produced easy to detect galaxies. Indeed, the apparent youth of some LSB galaxies suggest that galaxy formation is a greatly extended process. While the discovery of LSB galaxies have lead to new insights, it remains unwise to presume that we now have a representative sample which encompasses all galaxy types and forms. (SECTION: Invited Review Paper)

The Bright Universe Cosmology

International Nuclear Information System (INIS)

Surdin, M.

1980-01-01

It is shown that viewed from the 'outside', our universe is a black hole. Hence the 'inside' cosmology considered is termed as the Bright Universe Cosmology. The model proposed avoids the singularities of cosmologies of the Big Bang variety, it gives a good account of the redshifts, the cosmic background radiation, the number counts; it also gives a satisfactory explanation of the 'large numbers coincidence' and of the variation in time of fundamental constants. (Auth.)

Bright intracranial lesions on diffusion-weighted images: a pictorial review

International Nuclear Information System (INIS)

Choi, Dae Seob

2006-01-01

Diffusion-weighted imaging (DWI) is a MR sequence that is used to evaluate the rate of microscopic water diffusion within the tissues. The ability to measure the rate of water diffusion is important because this is frequently altered in various disease processes. Generally, the lesions with restricted water diffusion show bright intensity on DWI, but the lesions without restricted water diffusion can also show bright intensity on DWI, which is called the 'T2 shine through effect'. With DWI, we can sensitively detect hyperacute infarction (within 6 hours after symptom onset), and this is difficult to detect with using CT and the conventional MR sequenced. The acute and subacute lesions of hypoxic-ischemic encephalopathy and carbon monoxide intoxication also show bright intensity on the DWI. The other diseases that can show bright intensity on the DWI include acute and subacute diffuse axonal injury lesion, hyperacute and late subacute hematomas, cerebral abscess, subdural empyema, acute herpes encephalitis, various tumors and such degenerative and demyelinating diseases as multiple sclerosis, posterior reversible encephalopathy syndrome, Wilson's disease and Wernicke's encephalopathy

Bright intracranial lesions on diffusion-weighted images: a pictorial review

Energy Technology Data Exchange (ETDEWEB)

Choi, Dae Seob [Gyeongsang National University College of Medicine, Jinju (Korea, Republic of)

2006-06-15

Diffusion-weighted imaging (DWI) is a MR sequence that is used to evaluate the rate of microscopic water diffusion within the tissues. The ability to measure the rate of water diffusion is important because this is frequently altered in various disease processes. Generally, the lesions with restricted water diffusion show bright intensity on DWI, but the lesions without restricted water diffusion can also show bright intensity on DWI, which is called the 'T2 shine through effect'. With DWI, we can sensitively detect hyperacute infarction (within 6 hours after symptom onset), and this is difficult to detect with using CT and the conventional MR sequenced. The acute and subacute lesions of hypoxic-ischemic encephalopathy and carbon monoxide intoxication also show bright intensity on the DWI. The other diseases that can show bright intensity on the DWI include acute and subacute diffuse axonal injury lesion, hyperacute and late subacute hematomas, cerebral abscess, subdural empyema, acute herpes encephalitis, various tumors and such degenerative and demyelinating diseases as multiple sclerosis, posterior reversible encephalopathy syndrome, Wilson's disease and Wernicke's encephalopathy.

High resolution radio observations of nuclear and circumnuclear regions of luminous infrared galaxies (LIRGs)

Energy Technology Data Exchange (ETDEWEB)

Alberdi, A; Perez-Torres, M A [Instituto de Astrofisica de Andalucia (IAA, CSIC), PO Box 3004, 18080-Granada (Spain); Colina, L [Instituto de Estructura de la Materia - IEM, CSIC, C, Serrano 115, 28005 Madrid (Spain); Torrelles, J M [Instituto de Ciencias del Espacio (ICE, CSIC) and IEEC, Gran Capita 2-4, 08034 Barcelona (Spain)], E-mail: antxon@iaa.es, E-mail: torres@iaa.es, E-mail: colina@damir.iem.csic.es, E-mail: torrelle@ieec.fcr.es

2008-10-15

High-resolution radio observations of the nuclear region of Luminous and Ultraluminous Infrared Galaxies (ULIRGs) have shown that its radio structure consists of a compact high surface-brightness central radio source immersed in a diffuse low brightness circumnuclear halo. While the central component could be associated with an AGN or compact star-forming regions where radio supernovae are exploding, it is well known that the circumnuclear regions host bursts of star-formation. The studies of radio supernovae can provide essential information about stellar evolution and CSM/ISM properties in regions hidden by dust at optical and IR wavelengths. In this contribution, we show results from radio interferometric observations from NGC 7469, IRAS 18293-3413 and IRAS 17138-1017 where three extremely bright radio supernovae have been found. High-resolution radio observations of these and other LIRGs would allow us to determine the core-collapse supernova rate in them as well as their star-formation rate.

SIMULTANEOUS MULTI-BAND DETECTION OF LOW SURFACE BRIGHTNESS GALAXIES WITH MARKOVIAN MODELING

International Nuclear Information System (INIS)

Vollmer, B.; Bonnarel, F.; Louys, M.; Perret, B.; Petremand, M.; Lavigne, F.; Collet, Ch.; Van Driel, W.; Sabatini, S.; MacArthur, L. A.

2013-01-01

reached for sources with r e > 3'' at a mean surface brightness level of μ g = 27.7 mag arcsec –2 and a central surface brightness of μ 0 g = 26.7 mag arcsec –2 . About 10% of the false positives are artifacts, the rest being background galaxies. We have found our proposed Markovian LSB galaxy detection method to be complementary to the application of matched filters and an optimized use of SExtractor, and to have the following advantages: it is scale free, can be applied simultaneously to several bands, and is well adapted for crowded regions on the sky.

Radio and infrared observations of the faint nebula GM24

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, L F; Roth, M; Tapia, M; Canto, J; Persi, P; Ferrari-Toniolo, M

1986-02-01

The faint nebulosity GM24=PP85 listed by Parsamian and Petrosian (1979) was observed at infrared (1-10 ..mu..m) and radio (6 cm and CO line) wavelengths in the vicinity of the CO hot spot reported by Torrelles et al. (1983). The radio continuum (6 cm) emission from a spherically symmetrical HII region was detected with the Very Large Array. Its position coincides with the brightest part of the visible nebulosity and a 1-4 ..mu..m emission peak. Their infrared maps made at the Observatorio Astronomico Nacional de San Pedro Martir, show two additional (1-10 ..mu..m) peaks located at distances approx. 30 arc sec from the compact HII region, all surrounded by extended near infrared (1-4 ..mu..m) emission. A detailed CO (J=1 ..-->.. 0) map of the whole molecular cloud was also obtained with the University of Texas Millimeter - Wave Telescope. Their results are interpreted in terms of the recent formation of three massive stars, one of which, having developed an HII region, is at a slightly later phase of its evolution. The extended near infrared emission may arise in a reflection nebula similar to NGC 7538-Irs 9. 4 references.

The Cosmic Abundance of 3He: Green Bank Telescope Observations

Science.gov (United States)

Balser, Dana; Bania, Thomas

2018-01-01

The Big Bang theory for the origin of the Universe predicts that during the first ~1,000 seconds significant amounts of the light elements (2H, 3He, 4He, and 7Li) were produced. Many generations of stellar evolution in the Galaxy modifies these primordial abundances. Observations of the 3He+ hyperfine transition in Galactic HII regions reveals a 3He/H abundance ratio that is constant with Galactocentric radius to within the uncertainties, and is consistent with the primordial value as determined from cosmic microwave background experiments (e.g., WMAP). This "3He Plateau" indicates that the net production and destruction of 3He in stars is approximately zero. Recent stellar evolution models that include thermohaline mixing, however, predict that 3He/H abundance ratios should slightly decrease with Galactocentric radius, or in places in the Galaxy with lower star formation rates. Here we discuss sensitive Green Bank Telescope (GBT) observations of 3He+ at 3.46 cm in a subset of our HII region sample. We develop HII region models and derive accurate 3He/H abundance ratios to better constrain these new stellar evolution models.

Propagating wave in active region-loops, located over the solar disk observed by the Interface Region Imaging Spectrograph

Science.gov (United States)

Zhang, B.; Hou, Y. J.; Zhang, J.

2018-03-01

Aims: We aim to ascertain the physical parameters of a propagating wave over the solar disk detected by the Interface Region Imaging Spectrograph (IRIS). Methods: Using imaging data from the IRIS and the Solar Dynamic Observatory (SDO), we tracked bright spots to determine the parameters of a propagating transverse wave in active region (AR) loops triggered by activation of a filament. Deriving the Doppler velocity of Si IV line from spectral observations of IRIS, we have determined the rotating directions of active region loops which are relevant to the wave. Results: On 2015 December 19, a filament was located on the polarity inversion line of the NOAA AR 12470. The filament was activated and then caused a C1.1 two-ribbon flare. Between the flare ribbons, two rotation motions of a set of bright loops were observed to appear in turn with opposite directions. Following the end of the second rotation, a propagating wave and an associated transverse oscillation were detected in these bright loops. In 1400 Å channel, there was bright material flowing along the loops in a wave-like manner, with a period of 128 s and a mean amplitude of 880 km. For the transverse oscillation, we tracked a given loop and determine the transverse positions of the tracking loop in a limited longitudinal range. In both of 1400 Å and 171 Å channels, approximately four periods are distinguished during the transverse oscillation. The mean period of the oscillation is estimated as 143 s and the displacement amplitude as between 1370 km and 690 km. We interpret these oscillations as a propagating kink wave and obtain its speed of 1400 km s-1. Conclusions: Our observations reveal that a flare associated with filament activation could trigger a kink propagating wave in active region loops over the solar disk. Movies associated to Figs. 1-4 are available at http://https://www.aanda.org

Near-Real-Time DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperatures

Data.gov (United States)

National Aeronautics and Space Administration — The Near-Real-Time DMSP SSM/I-SSMIS Daily Polar Gridded Brightness Temperature product provides near-real-time brightness temperatures for both the Northern and...

Bright solitons in Bose-Fermi mixtures

International Nuclear Information System (INIS)

Karpiuk, Tomasz; Brewczyk, Miroslaw; RzaPewski, Kazimierz

2006-01-01

We consider the formation of bright solitons in a mixture of Bose and Fermi degenerate gases confined in a three-dimensional elongated harmonic trap. The Bose and Fermi atoms are assumed to effectively attract each other whereas bosonic atoms repel each other. Strong enough attraction between bosonic and fermionic components can change the character of the interaction within the bosonic cloud from repulsive to attractive making thus possible the generation of bright solitons in the mixture. On the other hand, such structures might be in danger due to the collapse phenomenon existing in attractive gases. We show, however, that under some conditions (defined by the strength of the Bose-Fermi components attraction) the structures which neither spread nor collapse can be generated. For elongated enough traps the formation of solitons is possible even at the 'natural' value of the mutual Bose-Fermi ( 87 Rb- 40 K in our case) scattering length

Venus - Phoebe Region

Science.gov (United States)

1990-01-01

This Magellan radar image is of part of the Phoebe region of Venus. It is a mosaic of parts of revolutions 146 and 147 acquired in the first radar test on Aug. 16, 1990. The area in the image is located at 291 degrees east longitude, 19 degrees south latitude. The image shows an area 30 kilometers (19.6 miles) wide and 76 km (47 miles) long. On the basis of Pioneer Venus and Arecibo data, it is known that two major rift zones occur in southern Phoebe Regio and that they terminate at about 20 to 25 degrees south latitude, about 2,000 km (1,240 miles) apart. This image is of an area just north of the southern end of the western rift zone. The region is characterized by a complex geologic history involving both volcanism and faulting. Several of the geologic units show distinctive overlapping or cross cutting relationships that permit identification and separation of geologic events and construction of the geologic history of the region. The oldest rocks in this image form the complexly deformed and faulted, radar bright, hilly terrain in the northern half. Faults of a variety of orientations are observed. A narrow fault trough (about one-half to one km (three tenths to six tenths of a mile) wide is seen crossing the bright hills near the lower part in the middle of the image. This is one of the youngest faults in the faulted, hilly unit as it is seen to cut across many other structures. The fault trough in turn appears to be embayed and flooded by the darker plains that appear in the south half of the image. These plains are interpreted to be of volcanic origin. The dark plains may be formed of a complex of overlapping volcanic flows. For example, the somewhat darker region of plains in the lower left (southwest) corner of the image may be a different age series of plains forming volcanic lava flows. Finally, the narrow bright line crossing the image in its lower part is interpreted to be a fault which cross cuts both plains units and is thus the youngest event in

Tolerance of brightness and contrast adjustments on chronic apical abscess and apical granuloma interpretation

Science.gov (United States)

Purnamasari, L.; Iskandar, H. H. B.; Makes, B. N.

2017-08-01

In digitized radiography techniques, adjusting the image enhancement can improve the subjective image quality by optimizing the brightness and contrast for diagnostic needs. To determine the value range of image enhancement (brightness and contrast) on chronic apical abscess and apical granuloma interpretation. 30 periapical radiographs that diagnosed chronic apical abscess and 30 that diagnosed apical granuloma were adjusted by changing brightness and contrast values. The value range of brightness and contrast adjustment that can be tolerated in radiographic interpretations of chronic apical abscess and apical granuloma spans from -10 to +10. Brightness and contrast adjustments on digital radiographs do not affect the radiographic interpretation of chronic apical abscess and apical granuloma if conducted within the value range.

Bright Stuff on Ceres = Sulfates and Carbonates on CI Chondrites

Science.gov (United States)

Zolensky, Michael; Chan, Queenie H. S.; Gounelle, Matthieu; Fries, Marc

2016-01-01

Recent reports of the DAWN spacecraft's observations of the surface of Ceres indicate that there are bright areas, which can be explained by large amounts of the Mg sulfate hexahydrate (MgSO4•6(H2O)), although the identification appears tenuous. There are preliminary indications that water is being evolved from these bright areas, and some have inferred that these might be sites of contemporary hydro-volcanism. A heat source for such modern activity is not obvious, given the small size of Ceres, lack of any tidal forces from nearby giant planets, probable age and presumed bulk composition. We contend that observations of chondritic materials in the lab shed light on the nature of the bright spots on Ceres

The effect of whole-body cooling on brain metabolism following perinatal hypoxic-ischemic injury.

Science.gov (United States)

Corbo, Elizabeth T; Bartnik-Olson, Brenda L; Machado, Sandra; Merritt, T Allen; Peverini, Ricardo; Wycliffe, Nathaniel; Ashwal, Stephen

2012-01-01

Magnetic resonance imaging (MRI) and spectroscopy (MRS) have proven valuable in evaluating neonatal hypoxic-ischemic injury (HII). MRI scores in the basal ganglia of HII/HT(+) neonates were significantly lower than HII/HT(-) neonates, indicating less severe injury and were associated with lower discharge encephalopathy severity scores in the HII/HT(+) group (P = 0.01). Lactate (Lac) was detected in the occipital gray matter (OGM) and thalamus (TH) of significantly more HII/HT(-) neonates (31.6 and 35.3%) as compared to the HII/HT(+) group (10.5 and 15.8%). In contrast, the -N-acetylaspartate (NAA)-based ratios in the OGM and TH did not differ between the HII groups. Our data show that the HT was associated with a decrease in the number of HII neonates with detectable cortical and subcortical Lac as well as a decrease in the number of MRI-detectable subcortical lesions. We retrospectively compared the medical and neuroimaging data of 19 HII neonates who received 72 h of whole-body cooling (HII/HT(+)) with those of 19 noncooled HII neonates (HII/HT(-)) to determine whether hypothermia was associated with improved recovery from the injury as measured by MRI and MRS within the first 14 days of life. MRI scores and metabolite ratios of HII/HT(+) and HII/HT(-) neonates were also compared with nine healthy, nonasphyxiated "control" neonates.

Stellar population in star formation regions of galaxies

Science.gov (United States)

Gusev, Alexander S.; Shimanovskaya, Elena V.; Shatsky, Nikolai I.; Sakhibov, Firouz; Piskunov, Anatoly E.; Kharchenko, Nina V.

2018-05-01

We developed techniques for searching young unresolved star groupings (clusters, associations, and their complexes) and of estimating their physical parameters. Our study is based on spectroscopic, spectrophotometric, and UBVRI photometric observations of 19 spiral galaxies. In the studied galaxies, we found 1510 objects younger than 10 Myr and present their catalogue. Having combined photometric and spectroscopic data, we derived extinctions, chemical abundances, sizes, ages, and masses of these groupings. We discuss separately the specific cases, when the gas extinction does not agree with the interstellar one. We assume that this is due to spatial offset of Hii clouds with respect to the related stellar population.We developed a method to estimate age of stellar population of the studied complexes using their morphology and the relation with associated H emission region. In result we obtained the estimates of chemical abundances for 80, masses for 63, and ages for 57 young objects observed in seven galaxies.

Response of noctilucent cloud brightness to daily solar variations

Science.gov (United States)

Dalin, P.; Pertsev, N.; Perminov, V.; Dubietis, A.; Zadorozhny, A.; Zalcik, M.; McEachran, I.; McEwan, T.; Černis, K.; Grønne, J.; Taustrup, T.; Hansen, O.; Andersen, H.; Melnikov, D.; Manevich, A.; Romejko, V.; Lifatova, D.

2018-04-01

For the first time, long-term data sets of ground-based observations of noctilucent clouds (NLC) around the globe have been analyzed in order to investigate a response of NLC to solar UV irradiance variability on a day-to-day scale. NLC brightness has been considered versus variations of solar Lyman-alpha flux. We have found that day-to-day solar variability, whose effect is generally masked in the natural NLC variability, has a statistically significant effect when considering large statistics for more than ten years. Average increase in day-to-day solar Lyman-α flux results in average decrease in day-to-day NLC brightness that can be explained by robust physical mechanisms taking place in the summer mesosphere. Average time lags between variations of Lyman-α flux and NLC brightness are short (0-3 days), suggesting a dominant role of direct solar heating and of the dynamical mechanism compared to photodissociation of water vapor by solar Lyman-α flux. All found regularities are consistent between various ground-based NLC data sets collected at different locations around the globe and for various time intervals. Signatures of a 27-day periodicity seem to be present in the NLC brightness for individual summertime intervals; however, this oscillation cannot be unambiguously retrieved due to inevitable periods of tropospheric cloudiness.

A SOUTHERN SKY AND GALACTIC PLANE SURVEY FOR BRIGHT KUIPER BELT OBJECTS

International Nuclear Information System (INIS)

Sheppard, Scott S.; Udalski, Andrzej; Kubiak, Marcin; Pietrzynski, Grzegorz; Poleski, Radoslaw; Soszynski, Igor; Szymanski, Michal K.; Ulaczyk, Krzysztof; Trujillo, Chadwick

2011-01-01

About 2500 deg 2 of sky south of declination -25 0 and/or near the Galactic Plane were surveyed for bright outer solar system objects. This survey is one of the first large-scale southern sky and Galactic Plane surveys to detect dwarf planets and other bright Kuiper Belt Objects in the trans-Neptunian region. The survey was able to obtain a limiting R-band magnitude of 21.6. In all, 18 outer solar system objects were detected, including Pluto which was detected near the Galactic center using optimal image subtraction techniques to remove the high stellar density background. Fourteen of the detections were previously unknown trans-Neptunian objects, demonstrating that the southern sky had not been well searched to date for bright outer solar system objects. Assuming moderate albedos, several of the new discoveries from this survey could be in hydrostatic equilibrium and thus could be considered dwarf planets. Combining this survey with previous surveys from the northern hemisphere suggests that the Kuiper Belt is nearly complete to around 21st magnitude in the R band. All the main dynamical classes in the Kuiper Belt are occupied by at least one dwarf-planet-sized object. The 3:2 Neptune resonance, which is the innermost well-populated Neptune resonance, has several large objects while the main outer Neptune resonances such as the 5:3, 7:4, 2:1, and 5:2 do not appear to have any large objects. This indicates that the outer resonances are either significantly depleted in objects relative to the 3:2 resonance or have a significantly different assortment of objects than the 3:2 resonance. For the largest objects (H < 4.5 mag), the scattered disk population appears to have a few times more objects than the main Kuiper Belt (MKB) population, while the Sedna population could be several times more than that of the MKB.

Bright to dim oscillatory response of the Neurospora circadian oscillator.

Science.gov (United States)

Gooch, Van D; Johnson, Alicia E; Larrondo, Luis F; Loros, Jennifer J; Dunlap, Jay C

2014-02-01

The fungus Neurospora crassa constitutes an important model system extensively used in chronobiology. Several studies have addressed how environmental cues, such as light, can reset or synchronize a circadian system. By means of an optimized firefly luciferase reporter gene and a controllable lighting system, we show that Neurospora can display molecular circadian rhythms in dim light when cultures receive bright light prior to entering dim light conditions. We refer to this behavior as the "bright to dim oscillatory response" (BDOR). The bright light treatment can be applied up to 76 h prior to dim exposure, and it can be as short as 15 min in duration. We have characterized this response in respect to the duration of the light pulse, the time of the light pulse before dim, the intensity of dim light, and the oscillation dynamics in dim light. Although the molecular mechanism that drives the BDOR remains obscure, these findings suggest that a long-term memory of bright light exists as part of the circadian molecular components. It is important to consider the ecological significance of such dim light responses in respect to how organisms naturally maintain their timing mechanism in moonlight.

High-intensification regions of gravitational lenses

International Nuclear Information System (INIS)

Benson, J.R.; Cooke, J.H.

1979-01-01

We examine the intensification, I, near the singular points in the object plane of an extended spherical gravitational lens. Geometrical optics predicts an infinite I for a point object located on a singularity. The function I, however, turns out to be integrable over the object plane. We make a detailed physical optics calculation for I. No singularities appear, and there are some interesting, marginally detectable diffraction phenomena. The two types of bright regions, the ''halo'' and the ''spike,'' behave very differently. Simple order-of-magnitude expressions give estimates for the brightness and duration of a high-intensification event

Detecting gradual visual changes in colour and brightness agnosia: a double dissociation.

Science.gov (United States)

Nijboer, Tanja C W; te Pas, Susan F; van der Smagt, Maarten J

2011-03-09

Two patients, one with colour agnosia and one with brightness agnosia, performed a task that required the detection of gradual temporal changes in colour and brightness. The results for these patients, who showed anaverage or an above-average performance on several tasks designed to test low-level colour and luminance (contrast) perception in the spatial domain, yielded a double dissociation; the brightness agnosic patient was within the normal range for the coloured stimuli, but much slower to detect brightness differences, whereas the colour agnosic patient was within the normal range for the achromatic stimuli, but much slower for the coloured stimuli. These results suggest that a modality-specific impairment in the detection of gradual temporal changes might be related to, if not underlie, the phenomenon of visual agnosia.

The bright-star masks for the HSC-SSP survey

Science.gov (United States)

Coupon, Jean; Czakon, Nicole; Bosch, James; Komiyama, Yutaka; Medezinski, Elinor; Miyazaki, Satoshi; Oguri, Masamune

2018-01-01

We present the procedure to build and validate the bright-star masks for the Hyper-Suprime-Cam Strategic Subaru Proposal (HSC-SSP) survey. To identify and mask the saturated stars in the full HSC-SSP footprint, we rely on the Gaia and Tycho-2 star catalogues. We first assemble a pure star catalogue down to GGaia SSP, finding that our star catalogue is 99.2% pure down to GGaia SSP observations at "ftp://obsftp.unige.ch/pub/coupon/brightStarMasks/HSC-SSP/".

Featured Image: Bright Dots in a Sunspot

Science.gov (United States)

Kohler, Susanna

2018-03-01

This image of a sunspot, located in in NOAA AR 12227, was captured in December 2014 by the 0.5-meter Solar Optical Telescope on board the Hinode spacecraft. This image was processed by a team of scientists led by Rahul Yadav (Udaipur Solar Observatory, Physical Research Laboratory Dewali, India) in order to examine the properties of umbral dots: transient, bright features observed in the umbral region (the central, darkest part) of a sunspot. By exploring these dots, Yadav and collaborators learned how their properties relate to the large-scale properties of the sunspots in which they form for instance, how do the number, intensities, or filling factors of dots relate to the size of a sunspots umbra? To find out more about the authors results, check out the article below.Sunspot in NOAA AR 11921. Left: umbralpenumbral boundary. Center: the isolated umbra from the sunspot. Right: The umbra with locations of umbral dots indicated by yellow plus signs. [Adapted from Yadav et al. 2018]CitationRahul Yadav et al 2018 ApJ 855 8. doi:10.3847/1538-4357/aaaeba

Automated detection of very Low Surface Brightness galaxies in the Virgo Cluster

Science.gov (United States)

Prole, D. J.; Davies, J. I.; Keenan, O. C.; Davies, L. J. M.

2018-04-01

We report the automatic detection of a new sample of very low surface brightness (LSB) galaxies, likely members of the Virgo cluster. We introduce our new software, DeepScan, that has been designed specifically to detect extended LSB features automatically using the DBSCAN algorithm. We demonstrate the technique by applying it over a 5 degree2 portion of the Next-Generation Virgo Survey (NGVS) data to reveal 53 low surface brightness galaxies that are candidate cluster members based on their sizes and colours. 30 of these sources are new detections despite the region being searched specifically for LSB galaxies previously. Our final sample contains galaxies with 26.0 ≤ ⟨μe⟩ ≤ 28.5 and 19 ≤ mg ≤ 21, making them some of the faintest known in Virgo. The majority of them have colours consistent with the red sequence, and have a mean stellar mass of 106.3 ± 0.5M⊙ assuming cluster membership. After using ProFit to fit Sérsic profiles to our detections, none of the new sources have effective radii larger than 1.5 Kpc and do not meet the criteria for ultra-diffuse galaxy (UDG) classification, so we classify them as ultra-faint dwarfs.

High-brightness beamline for x-ray spectroscopy at the ALS

Energy Technology Data Exchange (ETDEWEB)

Perera, R.C.C.; Jones, G. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States); Lindle, D.W. [Univ. of Nevada, Las Vegas, NV (United States)

1997-04-01

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1-6 keV photon-energy range, designed to achieve the goals of high energy resolution, high flux, and high brightness at the sample. When completed later this year, it will be the first ALS monochromatic hard x-ray beamline, and its brightness will be an order of magnitude higher than presently available in this energy range. In addition, it will provide flux and resolution comparable to any other beamline now in operation. To achieve these goals, two technical improvements, relative to existing x-ray beamlines, were incorporated. First, a somewhat novel optical design for x-rays, in which matched toroidal mirrors are positioned before and after the double-crystal monochromator, was adopted. This configuration allows for high resolution by passing a collimated beam through the monochromator, and for high brightness by focusing the ALS source on the sample with unit magnification. Second, a new {open_quotes}Cowan type{close_quotes} double-crystal monochromator based on the design used at NSLS beamline X-24A was developed. The measured mechanical precision of this new monochromator shows significant improvement over existing designs, without using positional feedback available with piezoelectric devices. Such precision is essential because of the high brightness of the radiation and the long distance (12 m) from the source (sample) to the collimating (focusing) mirror. This combination of features will provide a bright, high resolution, and stable x-ray beam for use in the x-ray spectroscopy program at the ALS.

Brightness measurement of an electron impact gas ion source for proton beam writing applications

Energy Technology Data Exchange (ETDEWEB)

Liu, N.; Santhana Raman, P. [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore); Xu, X.; Pang, R.; Kan, J. A. van, E-mail: phyjavk@nus.edu.sg [Centre for Ion Beam Applications, Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Khursheed, A. [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583 (Singapore)

2016-02-15

We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

Bright triplet excitons in caesium lead halide perovskites

Science.gov (United States)

Becker, Michael A.; Vaxenburg, Roman; Nedelcu, Georgian; Sercel, Peter C.; Shabaev, Andrew; Mehl, Michael J.; Michopoulos, John G.; Lambrakos, Samuel G.; Bernstein, Noam; Lyons, John L.; Stöferle, Thilo; Mahrt, Rainer F.; Kovalenko, Maksym V.; Norris, David J.; Rainò, Gabriele; Efros, Alexander L.

2018-01-01

Nanostructured semiconductors emit light from electronic states known as excitons. For organic materials, Hund’s rules state that the lowest-energy exciton is a poorly emitting triplet state. For inorganic semiconductors, similar rules predict an analogue of this triplet state known as the ‘dark exciton’. Because dark excitons release photons slowly, hindering emission from inorganic nanostructures, materials that disobey these rules have been sought. However, despite considerable experimental and theoretical efforts, no inorganic semiconductors have been identified in which the lowest exciton is bright. Here we show that the lowest exciton in caesium lead halide perovskites (CsPbX3, with X = Cl, Br or I) involves a highly emissive triplet state. We first use an effective-mass model and group theory to demonstrate the possibility of such a state existing, which can occur when the strong spin-orbit coupling in the conduction band of a perovskite is combined with the Rashba effect. We then apply our model to CsPbX3 nanocrystals, and measure size- and composition-dependent fluorescence at the single-nanocrystal level. The bright triplet character of the lowest exciton explains the anomalous photon-emission rates of these materials, which emit about 20 and 1,000 times faster than any other semiconductor nanocrystal at room and cryogenic temperatures, respectively. The existence of this bright triplet exciton is further confirmed by analysis of the fine structure in low-temperature fluorescence spectra. For semiconductor nanocrystals, which are already used in lighting, lasers and displays, these excitons could lead to materials with brighter emission. More generally, our results provide criteria for identifying other semiconductors that exhibit bright excitons, with potential implications for optoelectronic devices.

The relationship between brightness temperature and soil moisture. Selection of frequency range for microwave remote sensing

International Nuclear Information System (INIS)

Rao, K.S.; Chandra, G.; Rao, P.V.N.

1987-01-01

The analysis of brightness temperature data acquired from field and aircraft experiments demonstrates a linear relationship between soil moisture and brightness temperature. However, the analysis of brightness temperature data acquired by the Skylab radiometer demonstrates a non-linear relationship between soil moisture and brightness temperature. In view of the above and also because of recent theoretical developments for the calculation of the dielectric constant and brightness temperature under varying soil moisture profile conditions, an attempt is made to study the theoretical relationship between brightness temperature and soil moisture as a function of frequency. Through the above analysis, the appropriate microwave frequency range for soil moisture studies is recommended

Artificial light alters natural regimes of night-time sky brightness

Science.gov (United States)

Davies, Thomas W.; Bennie, Jonathan; Inger, Richard; Gaston, Kevin J.

2013-01-01

Artificial light is globally one of the most widely distributed forms of anthropogenic pollution. However, while both the nature and ecological effects of direct artificial lighting are increasingly well documented, those of artificial sky glow have received little attention. We investigated how city lights alter natural regimes of lunar sky brightness using a novel ten month time series of measurements recorded across a gradient of increasing light pollution. In the city, artificial lights increased sky brightness to levels six times above those recorded in rural locations, nine and twenty kilometers away. Artificial lighting masked natural monthly and seasonal regimes of lunar sky brightness in the city, and increased the number and annual regime of full moon equivalent hours available to organisms during the night. The changes have potentially profound ecological consequences.

High-brightness H/sup -/ accelerators

International Nuclear Information System (INIS)

Jameson, R.A.

1987-01-01

Neutral particle beam (NPB) devices based on high-brightness H/sup -/ accelerators are an important component of proposed strategic defense systems. The basic rational and R and D program are outlined and examples given of the underlying technology thrusts toward advanced systems. Much of the research accomplished in the past year is applicable to accelerator systems in general; some of these activities are discussed

High-brightness electron injectors

International Nuclear Information System (INIS)

Sheffield, R.L.

1987-01-01

Free-electron laser (FEL) oscillators and synchrotron light sources require pulse trains of high peak brightness and, in some applications, high-average power. Recent developments in the technology of photoemissive and thermionic electron sources in rf cavities for electron-linac injector applications offer promising advances over conventional electron injectors. Reduced emittance growth in high peak-current electron injectors may be achieved by using high field strengths and by linearizing the radial component of the cavity electric field at the expense of lower shunt impedance

New far infrared images of bright, nearby, star-forming regions

Science.gov (United States)

Harper, D. AL, Jr.; Cole, David M.; Dowell, C. Darren; Lees, Joanna F.; Lowenstein, Robert F.

1995-01-01

Broadband imaging in the far infrared is a vital tool for understanding how young stars form, evolve, and interact with their environment. As the sensitivity and size of detector arrays has increased, a richer and more detailed picture has emerged of the nearest and brightest regions of active star formation. We present data on M 17, M 42, and S 106 taken recently on the Kuiper Airborne Observatory with the Yerkes Observatory 60-channel far infrared camera, which has pixel sizes of 17 in. at 60 microns, 27 in. at 100 microns, and 45 in. at 160 and 200 microns. In addition to providing a clearer view of the complex central cores of the regions, the images reveal new details of the structure and heating of ionization fronts and photodissociation zones where radiation form luminous stars interacts with adjacent molecular clouds.

High intensity region segmentation in MR imaging of multiple sclerosis

International Nuclear Information System (INIS)

Rodrigo, F; Filipuzzi, M; Graffigna, J P; Isoardi, R; Noceti, M

2013-01-01

Numerous pathologies are often manifest in Magnetic Resonance Imaging (MRI) as hyperintense or bright regions as compared to normal tissue. It is of particular interest to develop an algorithm to detect, identify and define those Regions of Interest (ROI) when analyzing MRI studies, particularly for lesions of Multiple Sclerosis (MS). The objective of this study is to analyze those parameters which optimize segmentation of the areas of interest. To establish which areas should be considered as hyperintense regions, we developed a database (DB), with studies of patients diagnosed with MS. This disease causes axonal demyelination and it is expressed as bright regions in PD, T2 and FLAIR MRI sequences. Thus, with more than 4300 hyperintense regions validated by an expert physician, an algorithm was developed to detect such spots, approximating the results the expert obtained. Alongside these hyperintense lesion regions, it also detected bone regions with high intensity levels, similar to the intensity of the lesions, but with other features that allow a good differentiation.The algorithm will then detect ROIs with similar intensity levels and performs classification through data mining techniques

Efficiency of observer brightness discrimination in original and subracted images

International Nuclear Information System (INIS)

Swensson, R.G.; Kazda, I.; Nawfel, R.; Judy, P.F.

1990-01-01

This paper reports that, for an optimal image calculation, discriminating pairs of objects that differ only in brightness is equivalent to discriminating polarity differences in their subtraction images. This experiment measured and compared how efficiently human observers could perform the two different discriminations posed by such original and subtracted images. Disks of equal size, separated by their diameter, were superimposed on incorrelated, Gaussian noise backgrounds at different contrasts that made the two disks readily visible on the displayed radiographs. The digitally subtracted image-regions containing the two disks of each pair (shifted to registration) produced subtraction images with low-contrast disks that were either brighter or darker than the background. Observer performances in each task (measured by receiver operating characteristic [ROC] analysis) was compared with that of an optimal calculation (cross- correlator)

SIMULTANEOUS MULTI-BAND DETECTION OF LOW SURFACE BRIGHTNESS GALAXIES WITH MARKOVIAN MODELING

Energy Technology Data Exchange (ETDEWEB)

Vollmer, B.; Bonnarel, F.; Louys, M. [CDS, Observatoire Astronomique, UMR 7550, 11 rue de l' universite, F-67000 Strasbourg (France); Perret, B.; Petremand, M.; Lavigne, F.; Collet, Ch. [LSIIT, Universite de Strasbourg, 7, Rue Rene Descartes, F-67084 Strasbourg (France); Van Driel, W. [GEPI, Observatoire de Paris, CNRS, Universite Paris Diderot, 5 place Jules Janssen, F-92190 Meudon (France); Sabatini, S. [INAF/IASF-Roma, via Fosso de Cavaliere 100, I-00133 Roma (Italy); MacArthur, L. A., E-mail: Bernd.Vollmer@astro.unistra.fr [Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, BC V9E 2E7 (Canada)

2013-02-01

90% is reached for sources with r{sub e} > 3'' at a mean surface brightness level of {mu}{sub g} = 27.7 mag arcsec{sup -2} and a central surface brightness of {mu}{sup 0}{sub g} = 26.7 mag arcsec{sup -2}. About 10% of the false positives are artifacts, the rest being background galaxies. We have found our proposed Markovian LSB galaxy detection method to be complementary to the application of matched filters and an optimized use of SExtractor, and to have the following advantages: it is scale free, can be applied simultaneously to several bands, and is well adapted for crowded regions on the sky.

Sky Brightness During Eclipses: A Compendium from the Literature

Science.gov (United States)

1974-08-05

Star Sightings 1880A 11 Jan 1880 Santa- Lucia Jupiter -3 Mars .3 No stars 1882A 17 May 1882 Sohag, Egypt Stars shone brightly 1883A 6 M.»y 1883...1870 E 1880 A 1886 BA 1887 F 1889 A2 1900 EB 1914 A 1927 B Location London Venice Bue Island Gottenbui g Vumpurthy Seville Santa- Lucia ...manner, and at the peak of day the stars ap- peared brightly. (Tatti Annali sacri della citta di Como.) 5 MAY 840 840 DB Ginzel p. 668 Italy In

Relationships between brightness of nighttime lights and population density

Science.gov (United States)

Naizhuo, Z.

2012-12-01

lit area, relatively large under-estimations would emerge in the urban core regions. Previous studies have shown that GDP, carbon dioxide emission, and electric power consumption strongly correlate to urban population (Ghosh et al., 2010; Sutton et al., 2007; Zhao et al., 2012). Thus, although this study only examined the relationships between brightness of nighttime lights and population density, the results can provide insight for the spatial disaggregations of socioeconomic data (e.g. GDP, carbon dioxide emission, and electric power consumption) using the satellite nighttime light image data. Simply distributing the socioeconomic data to each pixel in proportion to the DN value of the nighttime light images may generate relatively large errors. References Bharit N, Tatem AJ, Ferrari MJ, Grais RF, Djibo A, Grenfell BT, 2011. Science, 334:1424-1427. Ghosh T, Elvidge CD, Sutton PC, Baugh KE, Ziskin D, Tuttle BT, 2010. Energies, 3:1895-1913. Oda T, Maksyutov S, 2011. Atmospheric Chemistry and Physics, 11:543-556. Sutton PC, Elvidge CD, Ghosh T, 2007. International Journal of Ecological Economics and Statistics, 8:5-21. Zhao N, Ghosh T, Samson EL, 2012. International Journal of Remote sensing, 33:6304-6320.

Internal differential rotation of the Sun: the P-modes frequency splitting in the measurements of brightness oscillations

International Nuclear Information System (INIS)

Didkovskij, L.V.

1989-01-01

a 12-DAY SERIES OF TWO-DIMNIONAL IMAGES OF SOLAR BRIGHTNESS OSCILLATIONS EIGENFREQUENCIES in the range of 6-32 degrees. The rotational frequency splitting of separate modes as a function of inner turn-points radius of acoustic waves is found. The results of the analysis shw fast rotation of the central region of the Sun and non-monotonous trend of angular rotation velocity varitions with radius of the boundary of solar core

Investigating a population of infrared-bright gamma-ray burst host galaxies

Science.gov (United States)

Chrimes, Ashley A.; Stanway, Elizabeth R.; Levan, Andrew J.; Davies, Luke J. M.; Angus, Charlotte R.; Greis, Stephanie M. L.

2018-04-01

We identify and explore the properties of an infrared-bright gamma-ray burst (GRB) host population. Candidate hosts are selected by coincidence with sources in WISE, with matching to random coordinates and a false alarm probability analysis showing that the contamination fraction is ˜ 0.5. This methodology has already identified the host galaxy of GRB 080517. We combine survey photometry from Pan-STARRS, SDSS, APASS, 2MASS, GALEX and WISE with our own WHT/ACAM and VLT/X-shooter observations to classify the candidates and identify interlopers. Galaxy SED fitting is performed using MAGPHYS, in addition to stellar template fitting, yielding 13 possible IR-bright hosts. A further 7 candidates are identified from previously published work. We report a candidate host for GRB 061002, previously unidentified as such. The remainder of the galaxies have already been noted as potential hosts. Comparing the IR-bright population properties including redshift z, stellar mass M⋆, star formation rate SFR and V-band attenuation AV to GRB host catalogues in the literature, we find that the infrared-bright population is biased toward low z, high M⋆ and high AV. This naturally arises from their initial selection - local and dusty galaxies are more likely to have the required IR flux to be detected in WISE. We conclude that while IR-bright GRB hosts are not a physically distinct class, they are useful for constraining existing GRB host populations, particularly for long GRBs.

The Eindhoven High-Brightness Electron Programme

NARCIS (Netherlands)

Brussaard, G.J.H.; Wiel, van der M.J.

2004-01-01

The Eindhoven High-Brightness programme is aimed at producing ultra-short intense electron bunches from compact accelerators. The RF electron gun is capable of producing 100 fs electron bunches at 7.5 MeV and 10 pC bunch charge. The DC/RF hybrid gun under development will produce bunches <75 fs at

The bidirectional congruency effect of brightness-valence metaphoric association in the Stroop-like and priming paradigms.

Science.gov (United States)

Huang, Yanli; Tse, Chi-Shing; Xie, Jiushu

2017-11-04

The conceptual metaphor theory (Lakoff & Johnson, 1980, 1999) postulates a unidirectional metaphoric association between abstract and concrete concepts: sensorimotor experience activated by concrete concepts facilitates the processing of abstract concepts, but not the other way around. However, this unidirectional view has been challenged by studies that reported a bidirectional metaphoric association. In three experiments, we tested the directionality of the brightness-valence metaphoric association, using Stroop-like paradigm, priming paradigm, and Stroop-like paradigm with a go/no-go manipulation. Both mean and vincentile analyses of reaction time data were performed. We showed that the directionality of brightness-valence metaphoric congruency effect could be modulated by the activation level of the brightness/valence information. Both brightness-to-valence and valence-to-brightness metaphoric congruency effects occurred in the priming paradigm, which could be attributed to the presentation of prime that pre-activated the brightness or valence information. However, in the Stroop-like paradigm the metaphoric congruency effect was only observed in the brightness-to-valence direction, but not in the valence-to-brightness direction. When the go/no-go manipulation was used to boost the activation of word meaning in the Stroop-like paradigm, the valence-to-brightness metaphoric congruency effect was observed. Vincentile analyses further revealed that valence-to-brightness metaphoric congruency effect approached significance in the Stroop-like paradigm when participants' reaction times were slower (at around 490ms). The implications of the current findings on the conceptual metaphor theory and embodied cognition are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Three Bright X-ray Sources in NGC 1313

Science.gov (United States)

Colbert, E.; Petre, R.; Schlegel, E.

1992-12-01

Three bright X-ray sources were detected in a recent (April/May 1991) ROSAT PSPC observation of the nearby (D ~ 4.5 Mpc) face--on barred spiral galaxy NGC 1313. Two of the sources were at positions coincident with X-ray sources detected by Fabbiano & Trinchieri (ApJ 315, 1987) in a previous (Jan 1980) Einstein IPC observation. The position of the brightest Einstein source is near the center of NGC 1313, and the second Einstein source is ~ 7' south of the ``nuclear'' source, in the outskirts of the spiral arms. A third bright X-ray source was detected in the ROSAT observation ~ 7' southwest of the ``nuclear'' source. We present X-ray spectra and X-ray images for the three bright sources found in the ROSAT observation of NGC 1313, and compare with previous Einstein results. Spectral analysis of these sources require them to have very large soft X-ray luminosities ( ~ 10(40) erg s(-1) ) when compared with typical X-ray sources in our Galaxy. Feasible explanations for the X-ray emission are presented. The third X-ray source is positively identified with the recently discovered (Ryder et. al., ApJ 1992) peculiar type-II supernova 1978K.

Bright patches on chernozems - from space to surface and soil properties

Science.gov (United States)

Smetanova, Anna; Burian, Libor; Holec, Juraj; Minár, Jozef

2016-04-01

The bright patches on chernozems can be easily visually distinguished in the aerial images, due to their bright colour contrasting with the dark colour of the surrounding chernozems. They present a typical feature of the loess hilly lands in the Danube Lowland. They reffer predominantely to the areas where (i) the soil substrate - loess is tilled, (ii) the transitional AC horizon of chernozems is tilled, (iii) or one of them, or both are mixed into the plough layer during tillage. They are usually categorized as eroded chernozems or regosols. To the lower extent, the accumulation patches might occur, if the loess material redeposited from upper part of the slope in the colluvium is tilled. This study focuses on uncovering the soil properties of bright patches, identified on different scales - spatial and temporal, combining three methods - the remote sensing, morphometric analysis and soil mapping. In the area of 31 km² (located in the Trnavska pahorkatina Hilly Land, south of Trnava), the bright patches were identified using visual analysis of georeferenced aerial images from 1949 and 2004, representing two types of landscape structure characteristic for the 20th Century. In 1949 small, in one direction elongated fields, with mean size 0.008 km2 prevailed, while in 2004 the mean size of a field was 0.28 km2. The morphometric analysis was performed based on DEM derived from topographical maps (scale 1:10 000). Soil sampling in the first phase of the project was performed in a subset of the patches in small agriculture catchment (0.28 km2), situated in one single field (in 2004). The percussion drilling or hand augering (with undisturbed structure) were used in order to describe the depth of the soil horizons and the soil properties. Together 365 bright patches covering 3.2% of the study area (31 km²) were identified in 1949; while it was twice more in 2004 (776 patches), when they covered approximately 12% of the same area. The bright patches were predominantly

Analytically derived conversion of spectral band radiance to brightness temperature

Energy Technology Data Exchange (ETDEWEB)

Berk, Alexander [Spectral Sciences, Inc., 44th Avenue, Burlington, MA 01803 (United States)], E-mail: lex@spectral.com

2008-05-15

Simple analytic expressions for brightness temperature have been derived in terms of band response function spectral moments. Accuracy measures are also derived. Application of these formulas to GOES-12 Sounder thermal infrared bands produces brightness temperature residuals between -5.0 and 2.5 mK for a 150-400 K temperature range. The magnitude of residuals for the five ASTER Radiometer thermal infrared bands over the same temperature range is less than 0.22 mK.

Bright matter wave solitons and their collision in Bose-Einstein condensates

International Nuclear Information System (INIS)

Radha, R.; Ramesh Kumar, V.

2007-01-01

We obtain the bright matter wave solitons in Bose-Einstein condensates from a trivial input solution by solving the time dependent Gross-Pitaevskii (GP) equation with quadratic potential and exponentially varying scattering length. We observe that the matter wave density of bright soliton increases with time by virtue of the exponentially increasing scattering length. We also understand that the matter wave densities of bright soliton trains remain finite despite the exchange of atoms during interaction and they travel along different trajectories (diverge) after interaction. We also observe that their amplitudes continue to fluctuate with time. For exponentially decaying scattering lengths, instability sets in the condensates. However, the scattering length can be suitably manipulated without causing the explosion or the collapse of the condensates

Three-dimensional analysis of free-electron laser performance using brightness scaled variables

Directory of Open Access Journals (Sweden)

M. Gullans

2008-06-01

Full Text Available A three-dimensional analysis of radiation generation in a free-electron laser (FEL is performed in the small signal regime. The analysis includes beam conditioning, harmonic generation, flat beams, and a new scaling of the FEL equations using the six-dimensional beam brightness. The six-dimensional beam brightness is an invariant under Liouvillian flow; therefore, any nondissipative manipulation of the phase space, performed, for example, in order to optimize FEL performance, must conserve this brightness. This scaling is more natural than the commonly used scaling with the one-dimensional growth rate. The brightness-scaled equations allow for the succinct characterization of the optimal FEL performance under various additional constraints. The analysis allows for the simple evaluation of gain enhancement schemes based on beam phase space manipulations such as emittance exchange and conditioning. An example comparing the gain in the first and third harmonics of round or flat and conditioned or unconditioned beams is presented.

The SDSS view of the Palomar-Green bright quasar survey

Energy Technology Data Exchange (ETDEWEB)

Jester, Sebastian; Schneider, Donald P.; Richards, Gordon T.; Green, Richard F.; Schmidt, Maarten; Hall, Patrick B.; Strauss, Michael A.; Vanden Berk, Daniel E.; Stoughton, Chris; Gunn, James E.; Brinkmann, Jon; Kent, Stephen M.; Smith, J.Allyn; Tucker, Douglas, L.; Yanny, Brian; /Fermilab /Penn State U., Astron. Astrophys. /Princeton U.

2005-02-01

The author investigates the extent to which the Palomar-Green (PG) Bright Quasar Survey (BQS) is complete and representative of the general quasar population by comparing with imaging and spectroscopy from the Sloan Digital Sky Survey. A comparison of SDSS and PG photometry of both stars and quasars reveals the need to apply a color and magnitude recalibration to the PG data. Using the SDSS photometric catalog, they define the PG's parent sample of objects that are not main-sequence stars and simulate the selection of objects from this parent sample using the PG photometric criteria and errors. This simulation shows that the effective U-B cut in the PG survey is U-B < -0.71, implying a color-related incompleteness. As the color distribution of bright quasars peaks near U-B = -0.7 and the 2-{sigma} error in U-B is comparable to the full width of the color distribution of quasars, the color incompleteness of the BQS is approximately 50% and essentially random with respect to U-B color for z < 0.5. There is however, a bias against bright quasars at 0.5 < z < 1, which is induced by the color-redshift relation of quasars (although quasars at z > 0.5 are inherently rare in bright surveys in any case). They find no evidence for any other systematic incompleteness when comparing the distributions in color, redshift, and FIRST radio properties of the BQS and a BQS-like subsample of the SDSS quasar sample. However, the application of a bright magnitude limit biases the BQS toward the inclusion of objects which are blue in g-i, in particular compared to the full range of g-i colors found among the i-band limited SDSS quasars, and even at i-band magnitudes comparable to those of the BQS objects.

Influences of diurnal bright or dim light exposure on urine volume in humans.

Science.gov (United States)

Hyun, Ki-Ja; Nishimura, Shinya; Tokura, Hiromi

2006-03-01

We investigated with eight healthy females if 8 hr diurnal (0700 to 1500 h) bright rather than dim light (5,000 vs. 80 lx) influenced urine volume. Environmental illuminance was made identical at all other times besides 07:00 to 15:00 h. The participants spent time at strictly regulated schedules in a bioclimatic chamber (26 degrees C, relative humidity 60%) for 57 h. Blood was drawn (2 ml) just before lunch in order to calculate Creatinine clearance (Ccr). Urine volume was significantly higher during wakefulness and the 8-h sleep period with bright rather than dim light. Ccr was significantly higher after bright light. The results were discussed in terms of suppression of the sympathetic nerve system under the influence of diurnal bright light exposure. We also discussed these in terms of physiological polymorphisms.

ASAS-SN Discovery of a Bright Be Star Undergoing a Possible Outburst

Science.gov (United States)

Jayasinghe, T.; Stanek, K. Z.; Kochanek, C. S.; Thorstensen, J.; Rupert, J.; Prieto, J. L.; Shields, J. V.; Thompson, T. A.; Holoien, T. W.-S.; Shappee, B. J.; Dong, Subo

2017-09-01

As part of an ongoing effort by ASAS-SN project (Shappee et al. 2014; Kochanek et al. 2017) to characterize and catalog all bright variable stars (e.g., Jayasinghe et al. 2017, ATel #10634, #10677), we report the discovery of a bright Be star undergoing a possible outburst.

Bright green light treatment of depression for older adults [ISRCTN69400161

Directory of Open Access Journals (Sweden)

Knickerbocker Nancy C

2005-11-01

Full Text Available Abstract Background Bright white light has been successfully used for the treatment of depression. There is interest in identifying which spectral colors of light are the most efficient in the treatment of depression. It is theorized that green light could decrease the intensity duration of exposure needed. Late Wake Treatment (LWT, sleep deprivation for the last half of one night, is associated with rapid mood improvement which has been sustained by light treatment. Because spectral responsiveness may differ by age, we examined whether green light would provide efficient antidepressant treatment in an elder age group. Methods We contrasted one hour of bright green light (1,200 Lux and one hour of dim red light placebo ( Results The protocol was completed by 33 subjects who were 59 to 80 years old. Mood improved on average 23% for all subjects, but there were no significant statistical differences between treatment and placebo groups. There were negligible adverse reactions to the bright green light, which was well tolerated. Conclusion Bright green light was not shown to have an antidepressant effect in the age group of this study, but a larger trial with brighter green light might be of value.

Fluorescence brightness and photostability of individual copper (I) oxide nanocubes.

Science.gov (United States)

Zohora, Nafisa; Kandjani, Ahmad Esmaielzadeh; Orth, Antony; Brown, Hannah M; Hutchinson, Mark R; Gibson, Brant C

2017-12-04

Conventional organic fluorophores lose their ability to fluoresce after repeated exposure to excitation light due to photobleaching. Therefore, research into emerging bright and photostable nanomaterials has become of great interest for a range of applications such as bio-imaging and tracking. Among these emerging fluorophores, metal oxide-based nanomaterials have attracted significant attention as a potential multifunctional material with photocatalytic and angeogenisis abilities in addition to fluorescnce applications. However, most of these applications are highly dependent on size, morphology, and chemo-physical properties of individual particles. In this manuscript, we present a method to study the intrinsic optical characteristics of individual copper (I) oxide (Cu 2 O) nanocubes. When excited at 520 nm using only 11 µW excitation power (1.7 W/cm2), individual nanocubes were observed to emit light with peak wavelengths ~760 nm which is conveniently within the near-infrared 1 (NIR1) biological window where tissue autofluorescence is minimal. Bright and photostable fluorescence was observed with intensities up to 487 K counts/s under constant illumination for at least 2 minutes with a brightness approximately four times higher than the autofluorescence from a fixed cumulus-oocyte complex. With near-IR emission, high fluorescence brightness, and outstanding photostability, Cu 2 O nanocubes are attractive candidates for long-term fluorescent bioimaging applications.

Bright solitons in coupled defocusing NLS equation supported by coupling: Application to Bose-Einstein condensation

International Nuclear Information System (INIS)

Adhikari, Sadhan K.

2005-01-01

We demonstrate the formation of bright solitons in coupled self-defocusing nonlinear Schroedinger (NLS) equation supported by attractive coupling. As an application we use a time-dependent dynamical mean-field model to study the formation of stable bright solitons in two-component repulsive Bose-Einstein condensates (BECs) supported by interspecies attraction in a quasi one-dimensional geometry. When all interactions are repulsive, there cannot be bright solitons. However, bright solitons can be formed in two-component repulsive BECs for a sufficiently attractive interspecies interaction, which induces an attractive effective interaction among bosons of same type

The star-bright hour : [luuletused] / Betti Alver

Index Scriptorium Estoniae

Alver, Betti, 1906-1989

2006-01-01

Sisu: The star-bright hour ; Not a dream ; The Piper ; Corals in an ancent river. Luuletused pärinevad kogumikust "Tuulelaeval valgusest on aerud = Windship with Oars of Light. (Tallinn : Huma, 2001). Orig.: Tähetund ; Mitte viirastus, meelepett ; Vilepuhuja ; Korallid Emajões

The star-bright hour : [poems] / Betti Alver

Index Scriptorium Estoniae

Alver, Betti, 1906-1989

2003-01-01

Autori lühitutvustus lk. 231. Sisu: The star-bright hour ; The debt ; Not a dream ; Fog-bound ; Corals in an Ancient river ; Frou-frou 1-3. Orig.: Tähetund ; Vilepuhuja ; Võlg ; "Mitte viirastus, meelepett..." ; Udus ; Korallid Emajões ; Froufrou 1-3

Simulated X-ray galaxy clusters at the virial radius: Slopes of the gas density, temperature and surface brightness profiles

Science.gov (United States)

Roncarelli, M.; Ettori, S.; Dolag, K.; Moscardini, L.; Borgani, S.; Murante, G.

2006-12-01

Using a set of hydrodynamical simulations of nine galaxy clusters with masses in the range 1.5 × 1014 matter of tension between simulated and observed properties, and up to the virial radius and beyond, where present observations are unable to provide any constraints. We have modelled the radial profiles between 0.3R200 and 3R200 with power laws with one index, two indexes and a rolling index. The simulated temperature and [0.5-2] keV surface brightness profiles well reproduce the observed behaviours outside the core. The shape of all these profiles in the radial range considered depends mainly on the activity of the gravitational collapse, with no significant difference among models including extraphysics. The profiles steepen in the outskirts, with the slope of the power-law fit that changes from -2.5 to -3.4 in the gas density, from -0.5 to -1.8 in the gas temperature and from -3.5 to -5.0 in the X-ray soft surface brightness. We predict that the gas density, temperature and [0.5-2] keV surface brightness values at R200 are, on average, 0.05, 0.60, 0.008 times the measured values at 0.3R200. At 2R200, these values decrease by an order of magnitude in the gas density and surface brightness, by a factor of 2 in the temperature, putting stringent limits on the detectable properties of the intracluster-medium (ICM) in the virial regions.

FIRST EXPERIMENTAL RESULTS FROM DEGAS, THE QUANTUM LIMITED BRIGHTNESS ELECTRON SOURCE

International Nuclear Information System (INIS)

Zolotorev, Max S.; Commins, Eugene D.; Oneill, James; Sannibale, Fernando; Tremsin, Anton; Wan, Weishi

2008-01-01

The construction of DEGAS (DEGenerate Advanced Source), a proof of principle for a quantum limited brightness electron source, has been completed at the Lawrence Berkeley National Laboratory. The commissioning and the characterization of this source, designed to generate coherent single electron 'bunches' with brightness approaching the quantum limit at a repetition rate of few MHz, has been started. In this paper the first experimental results are described

The ASAS-SN bright supernova catalogue - III. 2016

Science.gov (United States)

Holoien, T. W.-S.; Brown, J. S.; Stanek, K. Z.; Kochanek, C. S.; Shappee, B. J.; Prieto, J. L.; Dong, Subo; Brimacombe, J.; Bishop, D. W.; Bose, S.; Beacom, J. F.; Bersier, D.; Chen, Ping; Chomiuk, L.; Falco, E.; Godoy-Rivera, D.; Morrell, N.; Pojmanski, G.; Shields, J. V.; Strader, J.; Stritzinger, M. D.; Thompson, Todd A.; Woźniak, P. R.; Bock, G.; Cacella, P.; Conseil, E.; Cruz, I.; Fernandez, J. M.; Kiyota, S.; Koff, R. A.; Krannich, G.; Marples, P.; Masi, G.; Monard, L. A. G.; Nicholls, B.; Nicolas, J.; Post, R. S.; Stone, G.; Wiethoff, W. S.

2017-11-01

This catalogue summarizes information for all supernovae discovered by the All-Sky Automated Survey for SuperNovae (ASAS-SN) and all other bright (mpeak ≤ 17), spectroscopically confirmed supernovae discovered in 2016. We then gather the near-infrared through ultraviolet magnitudes of all host galaxies and the offsets of the supernovae from the centres of their hosts from public data bases. We illustrate the results using a sample that now totals 668 supernovae discovered since 2014 May 1, including the supernovae from our previous catalogues, with type distributions closely matching those of the ideal magnitude limited sample from Li et al. This is the third of a series of yearly papers on bright supernovae and their hosts from the ASAS-SN team.

Are numbers, size and brightness equally efficient in orienting visual attention? Evidence from an eye-tracking study.

Directory of Open Access Journals (Sweden)

Hermann Bulf

Full Text Available A number of studies have shown strong relations between numbers and oriented spatial codes. For example, perceiving numbers causes spatial shifts of attention depending upon numbers' magnitude, in a way suggestive of a spatially oriented, mental representation of numbers. Here, we investigated whether this phenomenon extends to non-symbolic numbers, as well as to the processing of the continuous dimensions of size and brightness, exploring whether different quantitative dimensions are equally mapped onto space. After a numerical (symbolic Arabic digits or non-symbolic arrays of dots; Experiment 1 or a non-numerical cue (shapes of different size or brightness level; Experiment 2 was presented, participants' saccadic response to a target that could appear either on the left or the right side of the screen was registered using an automated eye-tracker system. Experiment 1 showed that, both in the case of Arabic digits and dot arrays, right targets were detected faster when preceded by large numbers, and left targets were detected faster when preceded by small numbers. Participants in Experiment 2 were faster at detecting right targets when cued by large-sized shapes and left targets when cued by small-sized shapes, whereas brightness cues did not modulate the detection of peripheral targets. These findings indicate that looking at a symbolic or a non-symbolic number induces attentional shifts to a peripheral region of space that is congruent with the numbers' relative position on a mental number line, and that a similar shift in visual attention is induced by looking at shapes of different size. More specifically, results suggest that, while the dimensions of number and size spontaneously map onto an oriented space, the dimension of brightness seems to be independent at a certain level of magnitude elaboration from the dimensions of spatial extent and number, indicating that not all continuous dimensions are equally mapped onto space.

Are numbers, size and brightness equally efficient in orienting visual attention? Evidence from an eye-tracking study.

Science.gov (United States)

Bulf, Hermann; Macchi Cassia, Viola; de Hevia, Maria Dolores

2014-01-01

A number of studies have shown strong relations between numbers and oriented spatial codes. For example, perceiving numbers causes spatial shifts of attention depending upon numbers' magnitude, in a way suggestive of a spatially oriented, mental representation of numbers. Here, we investigated whether this phenomenon extends to non-symbolic numbers, as well as to the processing of the continuous dimensions of size and brightness, exploring whether different quantitative dimensions are equally mapped onto space. After a numerical (symbolic Arabic digits or non-symbolic arrays of dots; Experiment 1) or a non-numerical cue (shapes of different size or brightness level; Experiment 2) was presented, participants' saccadic response to a target that could appear either on the left or the right side of the screen was registered using an automated eye-tracker system. Experiment 1 showed that, both in the case of Arabic digits and dot arrays, right targets were detected faster when preceded by large numbers, and left targets were detected faster when preceded by small numbers. Participants in Experiment 2 were faster at detecting right targets when cued by large-sized shapes and left targets when cued by small-sized shapes, whereas brightness cues did not modulate the detection of peripheral targets. These findings indicate that looking at a symbolic or a non-symbolic number induces attentional shifts to a peripheral region of space that is congruent with the numbers' relative position on a mental number line, and that a similar shift in visual attention is induced by looking at shapes of different size. More specifically, results suggest that, while the dimensions of number and size spontaneously map onto an oriented space, the dimension of brightness seems to be independent at a certain level of magnitude elaboration from the dimensions of spatial extent and number, indicating that not all continuous dimensions are equally mapped onto space.

Arctic sea ice signatures: L-band brightness temperature sensitivity comparison using two radiation transfer models

Science.gov (United States)

Richter, Friedrich; Drusch, Matthias; Kaleschke, Lars; Maaß, Nina; Tian-Kunze, Xiangshan; Mecklenburg, Susanne

2018-03-01

Sea ice is a crucial component for short-, medium- and long-term numerical weather predictions. Most importantly, changes of sea ice coverage and areas covered by thin sea ice have a large impact on heat fluxes between the ocean and the atmosphere. L-band brightness temperatures from ESA's Earth Explorer SMOS (Soil Moisture and Ocean Salinity) have been proven to be a valuable tool to derive thin sea ice thickness. These retrieved estimates were already successfully assimilated in forecasting models to constrain the ice analysis, leading to more accurate initial conditions and subsequently more accurate forecasts. However, the brightness temperature measurements can potentially be assimilated directly in forecasting systems, reducing the data latency and providing a more consistent first guess. As a first step towards such a data assimilation system we studied the forward operator that translates geophysical parameters provided by a model into brightness temperatures. We use two different radiative transfer models to generate top of atmosphere brightness temperatures based on ORAP5 model output for the 2012/2013 winter season. The simulations are then compared against actual SMOS measurements. The results indicate that both models are able to capture the general variability of measured brightness temperatures over sea ice. The simulated brightness temperatures are dominated by sea ice coverage and thickness changes are most pronounced in the marginal ice zone where new sea ice is formed. There we observe the largest differences of more than 20 K over sea ice between simulated and observed brightness temperatures. We conclude that the assimilation of SMOS brightness temperatures yields high potential for forecasting models to correct for uncertainties in thin sea ice areas and suggest that information on sea ice fractional coverage from higher-frequency brightness temperatures should be used simultaneously.

Arctic sea ice signatures: L-band brightness temperature sensitivity comparison using two radiation transfer models

Directory of Open Access Journals (Sweden)

F. Richter

2018-03-01

Full Text Available Sea ice is a crucial component for short-, medium- and long-term numerical weather predictions. Most importantly, changes of sea ice coverage and areas covered by thin sea ice have a large impact on heat fluxes between the ocean and the atmosphere. L-band brightness temperatures from ESA's Earth Explorer SMOS (Soil Moisture and Ocean Salinity have been proven to be a valuable tool to derive thin sea ice thickness. These retrieved estimates were already successfully assimilated in forecasting models to constrain the ice analysis, leading to more accurate initial conditions and subsequently more accurate forecasts. However, the brightness temperature measurements can potentially be assimilated directly in forecasting systems, reducing the data latency and providing a more consistent first guess. As a first step towards such a data assimilation system we studied the forward operator that translates geophysical parameters provided by a model into brightness temperatures. We use two different radiative transfer models to generate top of atmosphere brightness temperatures based on ORAP5 model output for the 2012/2013 winter season. The simulations are then compared against actual SMOS measurements. The results indicate that both models are able to capture the general variability of measured brightness temperatures over sea ice. The simulated brightness temperatures are dominated by sea ice coverage and thickness changes are most pronounced in the marginal ice zone where new sea ice is formed. There we observe the largest differences of more than 20 K over sea ice between simulated and observed brightness temperatures. We conclude that the assimilation of SMOS brightness temperatures yields high potential for forecasting models to correct for uncertainties in thin sea ice areas and suggest that information on sea ice fractional coverage from higher-frequency brightness temperatures should be used simultaneously.

Exposure to bright light for several hours during the daytime lowers tympanic temperature

Science.gov (United States)

Aizawa, Seika; Tokura, H.

The present study investigates the effect on thympanic temperature of exposure to different light intensities for several hours during the daytime. Nine healthy young adult volunteers (two male, seven female) were exposed to bright light of 4000 lx or dim light of 100 lx during the daytime from 0930 to 1800 hours; the light condition was then kept at 100 lx for a further hour. Tympanic temperature was measured continuously at a neutral condition (28° C, 60% relative humidity) from 1000 to 1800 hours. Urinary samples were collected from 1100 to 1900 hours every 2 h, and melatonin excretion rate was measured by enzyme immunoassay. Of nine subjects, six showed clearly lower tympanic temperatures in the bright compared with the dim condition from 1400 to 1800 hours. Average tympanic temperatures were significantly lower in the bright than in the dim condition from 1645 to 1800 hours. Melatonin excretion rate tended to be higher in the bright than in the dim condition. It was concluded that exposure to bright light of 4000 lx during the daytime for several hours could reduce tympanic temperature, compared with that measured in dim light of 100 lx.

Exposure to bright light for several hours during the daytime lowers tympanic temperature.

Science.gov (United States)

Aizawa, S; Tokura, H

1997-11-01

The present study investigates the effect on thympanic temperature of exposure to different light intensities for several hours during the daytime. Nine healthy young adult volunteers (two male, seven female) were exposed to bright light of 4000 lx or dim light of 100 lx during the daytime from 0930 to 1800 hours; the light condition was then kept at 100 lx for a further hour. Tympanic temperature was measured continuously at a neutral condition (28 degrees C, 60% relative humidity) from 1000 to 1800 hours. Urinary samples were collected from 1100 to 1900 hours every 2 h, and melatonin excretion rate was measured by enzyme immunoassay. Of nine subjects, six showed clearly lower tympanic temperatures in the bright compared with the dim condition from 1400 to 1800 hours. Average tympanic temperatures were significantly lower in the bright than in the dim condition from 1645 to 1800 hours. Melatonin excretion rate tended to be higher in the bright than in the dim condition. It was concluded that exposure to bright light of 4000 lx during the daytime for several hours could reduce tympanic temperature, compared with that measured in dim light of 100 lx.

On correct evaluation techniques of brightness enhancement effect measurement data

Science.gov (United States)

Kukačka, Leoš; Dupuis, Pascal; Motomura, Hideki; Rozkovec, Jiří; Kolář, Milan; Zissis, Georges; Jinno, Masafumi

2017-11-01

This paper aims to establish confidence intervals of the quantification of brightness enhancement effects resulting from the use of pulsing bright light. It is found that the methods used so far may yield significant bias in the published results, overestimating or underestimating the enhancement effect. The authors propose to use a linear algebra method called the total least squares. Upon an example dataset, it is shown that this method does not yield biased results. The statistical significance of the results is also computed. It is concluded over an observation set that the currently used linear algebra methods present many patterns of noise sensitivity. Changing algorithm details leads to inconsistent results. It is thus recommended to use the method with the lowest noise sensitivity. Moreover, it is shown that this method also permits one to obtain an estimate of the confidence interval. This paper neither aims to publish results about a particular experiment nor to draw any particular conclusion about existence or nonexistence of the brightness enhancement effect.

Cell motility dynamics: a novel segmentation algorithm to quantify multi-cellular bright field microscopy images.

Directory of Open Access Journals (Sweden)

Assaf Zaritsky

Full Text Available Confocal microscopy analysis of fluorescence and morphology is becoming the standard tool in cell biology and molecular imaging. Accurate quantification algorithms are required to enhance the understanding of different biological phenomena. We present a novel approach based on image-segmentation of multi-cellular regions in bright field images demonstrating enhanced quantitative analyses and better understanding of cell motility. We present MultiCellSeg, a segmentation algorithm to separate between multi-cellular and background regions for bright field images, which is based on classification of local patches within an image: a cascade of Support Vector Machines (SVMs is applied using basic image features. Post processing includes additional classification and graph-cut segmentation to reclassify erroneous regions and refine the segmentation. This approach leads to a parameter-free and robust algorithm. Comparison to an alternative algorithm on wound healing assay images demonstrates its superiority. The proposed approach was used to evaluate common cell migration models such as wound healing and scatter assay. It was applied to quantify the acceleration effect of Hepatocyte growth factor/scatter factor (HGF/SF on healing rate in a time lapse confocal microscopy wound healing assay and demonstrated that the healing rate is linear in both treated and untreated cells, and that HGF/SF accelerates the healing rate by approximately two-fold. A novel fully automated, accurate, zero-parameters method to classify and score scatter-assay images was developed and demonstrated that multi-cellular texture is an excellent descriptor to measure HGF/SF-induced cell scattering. We show that exploitation of textural information from differential interference contrast (DIC images on the multi-cellular level can prove beneficial for the analyses of wound healing and scatter assays. The proposed approach is generic and can be used alone or alongside traditional

Cell motility dynamics: a novel segmentation algorithm to quantify multi-cellular bright field microscopy images.

Science.gov (United States)

Zaritsky, Assaf; Natan, Sari; Horev, Judith; Hecht, Inbal; Wolf, Lior; Ben-Jacob, Eshel; Tsarfaty, Ilan

2011-01-01

Confocal microscopy analysis of fluorescence and morphology is becoming the standard tool in cell biology and molecular imaging. Accurate quantification algorithms are required to enhance the understanding of different biological phenomena. We present a novel approach based on image-segmentation of multi-cellular regions in bright field images demonstrating enhanced quantitative analyses and better understanding of cell motility. We present MultiCellSeg, a segmentation algorithm to separate between multi-cellular and background regions for bright field images, which is based on classification of local patches within an image: a cascade of Support Vector Machines (SVMs) is applied using basic image features. Post processing includes additional classification and graph-cut segmentation to reclassify erroneous regions and refine the segmentation. This approach leads to a parameter-free and robust algorithm. Comparison to an alternative algorithm on wound healing assay images demonstrates its superiority. The proposed approach was used to evaluate common cell migration models such as wound healing and scatter assay. It was applied to quantify the acceleration effect of Hepatocyte growth factor/scatter factor (HGF/SF) on healing rate in a time lapse confocal microscopy wound healing assay and demonstrated that the healing rate is linear in both treated and untreated cells, and that HGF/SF accelerates the healing rate by approximately two-fold. A novel fully automated, accurate, zero-parameters method to classify and score scatter-assay images was developed and demonstrated that multi-cellular texture is an excellent descriptor to measure HGF/SF-induced cell scattering. We show that exploitation of textural information from differential interference contrast (DIC) images on the multi-cellular level can prove beneficial for the analyses of wound healing and scatter assays. The proposed approach is generic and can be used alone or alongside traditional fluorescence single

Robust fitting of diurnal brightness temperature cycle

CSIR Research Space (South Africa)

Udahemuka, G

2007-11-01

Full Text Available for a pixel concerned. Robust fitting of observed Diurnal Temperature Cycle (DTC) taken over a day of a given pixel without cloud cover and other abnormally conditions such as fire can give a data based brightness temperature model for a given pixel...

Human Adolescent Phase Response Curves to Bright White Light.

Science.gov (United States)

Crowley, Stephanie J; Eastman, Charmane I

2017-08-01

Older adolescents are particularly vulnerable to circadian misalignment and sleep restriction, primarily due to early school start times. Light can shift the circadian system and could help attenuate circadian misalignment; however, a phase response curve (PRC) to determine the optimal time for receiving light and avoiding light is not available for adolescents. We constructed light PRCs for late pubertal to postpubertal adolescents aged 14 to 17 years. Participants completed 2 counterbalanced 5-day laboratory sessions after 8 or 9 days of scheduled sleep at home. Each session included phase assessments to measure the dim light melatonin onset (DLMO) before and after 3 days of free-running through an ultradian light-dark (wake-sleep) cycle (2 h dim [~20 lux] light, 2 h dark). In one session, intermittent bright white light (~5000 lux; four 20-min exposures) was alternated with 10 min of dim room light once per day for 3 consecutive days. The time of light varied among participants to cover the 24-h day. For each individual, the phase shift to bright light was corrected for the free-run derived from the other laboratory session with no bright light. One PRC showed phase shifts in response to light start time relative to the DLMO and another relative to home sleep. Phase delay shifts occurred around the hours corresponding to home bedtime. Phase advances occurred during the hours surrounding wake time and later in the afternoon. The transition from delays to advances occurred at the midpoint of home sleep. The adolescent PRCs presented here provide a valuable tool to time bright light in adolescents.

Bright Soil Churned by Spirit's Sol 1861 Drive

Science.gov (United States)

2009-01-01

NASA's Mars Exploration Rover Spirit drove 22.7 meters (74 feet) toward the southwest on the 1,861st Martian day, or sol, of Spirit's mission on Mars (March 28, 2009). After the drive, the rover took this image with its front hazard-avoidance camera, looking back at the tracks from the drive. As usual since losing the use of its right-front wheel in 2006, Spirit drove backwards. The immobile right-front wheel churned up a long stripe of bright soil during this drive. Where Spirit has found such bright soil in the past, subsequent analysis of the composition found concentrations of sulfur or silica that testified to past action of water at the site. When members of the rover team saw the large quantity of bright soil exposed by the Sol 1861 drive, they quickly laid plans to investigate the composition with Spirit's alpha particle X-ray spectrometer. The Sol 1861 drive took the rover past the northwest corner of the low plateau called 'Home Plate,' making progress on a route around the western side of Home Plate. The edge of Home Plate forms the horizon on the right side of this image. Husband Hill is on the horizon on the left side. For scale, the parallel rover wheel tracks are about 1 meter (40 inches) apart. The rover's hazard-avoidance cameras take 'fisheye' wide-angle images.

STRUCTURAL VARIATION OF MOLECULAR GAS IN THE SAGITTARIUS ARM AND INTERARM REGIONS

Energy Technology Data Exchange (ETDEWEB)

Sawada, Tsuyoshi; Hasegawa, Tetsuo; Sugimoto, Masahiro [Joint ALMA Office, Alonso de Cordova 3107, Vitacura, Santiago 763-0355 (Chile); Koda, Jin [Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 (United States); Handa, Toshihiro, E-mail: sawada.tsuyoshi@nao.ac.jp [Department of Physics, Faculty of Science, Kagoshima University, 1-21-35 Korimoto, Kagoshima 890-0065 (Japan)

2012-06-20

We have carried out survey observations toward the Galactic plane at l Almost-Equal-To 38 Degree-Sign in the {sup 12}CO and {sup 13}CO J = 1-0 lines using the Nobeyama Radio Observatory 45 m telescope. A wide area (0.{sup 0}8 Multiplication-Sign 0.{sup 0}8) was mapped with high spatial resolution (17''). The line of sight samples the gas in both the Sagittarius arm and the interarm regions. The present observations reveal how the structure and physical conditions vary across a spiral arm. We classify the molecular gas in the line of sight into two distinct components based on its appearance: the bright and compact B component and the fainter and diffuse (i.e., more extended) D component. The B component is predominantly seen at the spiral arm velocities, while the D component dominates at the interarm velocities and is also found at the spiral arm velocities. We introduce the brightness distribution function and the brightness distribution index (BDI, which indicates the dominance of the B component) in order to quantify the map's appearance. The radial velocities of BDI peaks coincide with those of high {sup 12}CO J = 3-2/{sup 12}CO J = 1-0 intensity ratio (i.e., warm gas) and H II regions, and tend to be offset from the line brightness peaks at lower velocities (i.e., presumably downstream side of the arm). Our observations reveal that the gas structure at small scales changes across a spiral arm: bright and spatially confined structures develop in a spiral arm, leading to star formation at the downstream side, while extended emission dominates in the interarm region.

Size dependence of upconversion photoluminescence in MPA capped CdTe quantum dots: Existence of upconversion bright point

Energy Technology Data Exchange (ETDEWEB)

Ananthakumar, S. [Crystal Growth Centre, Anna University, Chennai 600025 (India); Jayabalan, J., E-mail: jjaya@rrcat.gov.in [Laser Physics Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Singh, Asha; Khan, Salahuddin [Laser Physics Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Babu, S. Moorthy [Crystal Growth Centre, Anna University, Chennai 600025 (India); Chari, Rama [Laser Physics Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)

2016-01-15

The photoluminescence (PL) from semiconductor quantum dots can show a “PL bright point”, that is the PL from as prepared quantum dots is maximum at a particular size. In this work we show that, for CdTe quantum dots, upconversion photoluminescence (UCPL) originating from nonlinear absorption shows a similar “UCPL bright point”. The PL and UCPL bright points occur at nearly the same size. The existence of a UCPL bright point has important implications for upconversion microscopy applications. - Highlights: • The size dependence of the upconversion photoluminescence (UCPL) spectrum of CdTe quantum dots has been reported. • We show that the UCPL from the CdTe quantum dots is highest at a particular size. • Thus the occurrence of a 'UCPL bright point' in CdTe quantum dots has been demonstrated. • It has been shown that the UCPL bright point occurs at nearly the same size as a normal bright point.

Size dependence of upconversion photoluminescence in MPA capped CdTe quantum dots: Existence of upconversion bright point

International Nuclear Information System (INIS)

Ananthakumar, S.; Jayabalan, J.; Singh, Asha; Khan, Salahuddin; Babu, S. Moorthy; Chari, Rama

2016-01-01

The photoluminescence (PL) from semiconductor quantum dots can show a “PL bright point”, that is the PL from as prepared quantum dots is maximum at a particular size. In this work we show that, for CdTe quantum dots, upconversion photoluminescence (UCPL) originating from nonlinear absorption shows a similar “UCPL bright point”. The PL and UCPL bright points occur at nearly the same size. The existence of a UCPL bright point has important implications for upconversion microscopy applications. - Highlights: • The size dependence of the upconversion photoluminescence (UCPL) spectrum of CdTe quantum dots has been reported. • We show that the UCPL from the CdTe quantum dots is highest at a particular size. • Thus the occurrence of a "UCPL bright point" in CdTe quantum dots has been demonstrated. • It has been shown that the UCPL bright point occurs at nearly the same size as a normal bright point.

Very bright, near-infrared single photon emitters in diamond

Directory of Open Access Journals (Sweden)

D. W. M. Lau

2013-09-01

Full Text Available We demonstrate activation of bright diamond single photon emitters in the near infrared range by thermal annealing alone, i.e., without ion implantation. The activation is crucially dependent on the annealing ambient. The activation of the single photon emitters is only observed when the sample is annealed in forming gas (4% H2 in Ar above temperatures of 1000 °C. By contrast, no emitters are activated by annealing in vacuum, oxygen, argon or deuterium. The emitters activated by annealing in forming gas exhibit very bright emission in the 730-760 nm wavelength range and have linewidths of ∼1.5-2.5 nm at room temperature.

Record high-average current from a high-brightness photoinjector

Energy Technology Data Exchange (ETDEWEB)

Dunham, Bruce; Barley, John; Bartnik, Adam; Bazarov, Ivan; Cultrera, Luca; Dobbins, John; Hoffstaetter, Georg; Johnson, Brent; Kaplan, Roger; Karkare, Siddharth; Kostroun, Vaclav; Li Yulin; Liepe, Matthias; Liu Xianghong; Loehl, Florian; Maxson, Jared; Quigley, Peter; Reilly, John; Rice, David; Sabol, Daniel [Cornell Laboratory for Accelerator-Based Sciences and Education, Cornell University, Ithaca, New York 14853 (United States); and others

2013-01-21

High-power, high-brightness electron beams are of interest for many applications, especially as drivers for free electron lasers and energy recovery linac light sources. For these particular applications, photoemission injectors are used in most cases, and the initial beam brightness from the injector sets a limit on the quality of the light generated at the end of the accelerator. At Cornell University, we have built such a high-power injector using a DC photoemission gun followed by a superconducting accelerating module. Recent results will be presented demonstrating record setting performance up to 65 mA average current with beam energies of 4-5 MeV.

Discussion of high brightness rf linear accelerators

International Nuclear Information System (INIS)

Jameson, R.A.

1987-01-01

The fundamental aspects of high-brightness rf linacs are outlined, showing the breadth and complexity of the technology and indicating that synergism with advancements in other areas is important. Areas of technology reviewed include ion sources, injectors, rf accelerator structures, beam dynamics, rf power, and automatic control

AXIAL RATIO OF EDGE-ON SPIRAL GALAXIES AS A TEST FOR BRIGHT RADIO HALOS

International Nuclear Information System (INIS)

Singal, J.; Jones, E.; Dunlap, H.; Kogut, A.

2015-01-01

We use surface brightness contour maps of nearby edge-on spiral galaxies to determine whether extended bright radio halos are common. In particular, we test a recent model of the spatial structure of the diffuse radio continuum by Subrahmanyan and Cowsik which posits that a substantial fraction of the observed high-latitude surface brightness originates from an extended Galactic halo of uniform emissivity. Measurements of the axial ratio of emission contours within a sample of normal spiral galaxies at 1500 MHz and below show no evidence for such a bright, extended radio halo. Either the Galaxy is atypical compared to nearby quiescent spirals or the bulk of the observed high-latitude emission does not originate from this type of extended halo. (letters)

Bright spots among the world’s coral reefs

Science.gov (United States)

Cinner, Joshua E.; Huchery, Cindy; MacNeil, M. Aaron; Graham, Nicholas A. J.; McClanahan, Tim R.; Maina, Joseph; Maire, Eva; Kittinger, John N.; Hicks, Christina C.; Mora, Camilo; Allison, Edward H.; D'Agata, Stephanie; Hoey, Andrew; Feary, David A.; Crowder, Larry; Williams, Ivor D.; Kulbicki, Michel; Vigliola, Laurent; Wantiez, Laurent; Edgar, Graham; Stuart-Smith, Rick D.; Sandin, Stuart A.; Green, Alison L.; Hardt, Marah J.; Beger, Maria; Friedlander, Alan; Campbell, Stuart J.; Holmes, Katherine E.; Wilson, Shaun K.; Brokovich, Eran; Brooks, Andrew J.; Cruz-Motta, Juan J.; Booth, David J.; Chabanet, Pascale; Gough, Charlie; Tupper, Mark; Ferse, Sebastian C. A.; Sumaila, U. Rashid; Mouillot, David

2016-07-01

Ongoing declines in the structure and function of the world’s coral reefs require novel approaches to sustain these ecosystems and the millions of people who depend on them. A presently unexplored approach that draws on theory and practice in human health and rural development is to systematically identify and learn from the ‘outliers’—places where ecosystems are substantially better (‘bright spots’) or worse (‘dark spots’) than expected, given the environmental conditions and socioeconomic drivers they are exposed to. Here we compile data from more than 2,500 reefs worldwide and develop a Bayesian hierarchical model to generate expectations of how standing stocks of reef fish biomass are related to 18 socioeconomic drivers and environmental conditions. We identify 15 bright spots and 35 dark spots among our global survey of coral reefs, defined as sites that have biomass levels more than two standard deviations from expectations. Importantly, bright spots are not simply comprised of remote areas with low fishing pressure; they include localities where human populations and use of ecosystem resources is high, potentially providing insights into how communities have successfully confronted strong drivers of change. Conversely, dark spots are not necessarily the sites with the lowest absolute biomass and even include some remote, uninhabited locations often considered near pristine. We surveyed local experts about social, institutional, and environmental conditions at these sites to reveal that bright spots are characterized by strong sociocultural institutions such as customary taboos and marine tenure, high levels of local engagement in management, high dependence on marine resources, and beneficial environmental conditions such as deep-water refuges. Alternatively, dark spots are characterized by intensive capture and storage technology and a recent history of environmental shocks. Our results suggest that investments in strengthening fisheries

A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling

Directory of Open Access Journals (Sweden)

J. Baumgardner

2007-01-01

Full Text Available In contrast to the polar aurora visible during geomagnetic storms, stable auroral red (SAR arcs offer a sub-visual manifestation of direct magnetosphere-ionosphere (M-I coupling at midlatitudes. The SAR arc emission at 6300 Å is driven by field-aligned magnetospheric energy transport from ring current/plasmapause locations into the ionosphere-thermosphere system. The first SAR arc was observed at the dawn of the space age (1956, and the typical brightness levels and occurrence patterns obtained from subsequent decades of observations appear to be consistent with the downward heat conduction theory, i.e., heated ambient F-layer electrons excite oxygen atoms to produce a spectrally pure emission. On very rare occasions, a SAR arc has been reported to be at brightness levels visible to the naked eye. Here we report on the first case of a very bright SAR arc (~13 kilo-Rayleighs observed by four diagnostic systems that sampled various aspects of the sub-auroral domain near Millstone Hill, MA, on the night of 29 October 1991: an imaging spectrograph, an all-sky camera, an incoherent scatter radar (ISR, and a DMSP satellite. Simulations of emission using the ISR and DMSP data with the MSIS neutral atmosphere succeed in reproducing the brightness levels observed. This provides a robust confirmation of M-I coupling theory in its most extreme aeronomic form within the innermost magnetosphere (L~2 during a rare superstorm event. The unusually high brightness value appears to be due to the rare occurrence of the heating of dense ionospheric plasma just equatorward of the trough/plasmapause location, in contrast to the more typical heating of the less dense F-layer within the trough.

Properties of bright solitons in averaged and unaveraged models for SDG fibres

Science.gov (United States)

Kumar, Ajit; Kumar, Atul

1996-04-01

Using the slowly varying envelope approximation and averaging over the fibre cross-section the evolution equation for optical pulses in semiconductor-doped glass (SDG) fibres is derived from the nonlinear wave equation. Bright soliton solutions of this equation are obtained numerically and their properties are studied and compared with those of the bright solitons in the unaveraged model.

Large-scale brightness inhomogeneities in the solar atmosphere

International Nuclear Information System (INIS)

Mitchell, W.E. Jr.

1982-01-01

The intensity residuals are analyzed from a series of solar limb-darkening measurements in the wavelength range 5656 to 2997 A. The lengths of residual strings of the same sign exceed expectation by several orders of magnitude. The power spectrum fo the residuals shows a weak excess around 6000 km. For further study the 34000 limb-darkening residuals are subdivided into 5100 bright and faint cells. The frequency distribution of cell sizes peaks around 4500 km and increases from center to limb, the faint cells showing the greater center-limb effect. The cells are also studied as to contrast. A synoptic view indicates that only 12% of the cells are identifiable after a half hour. Phenomena that may combine to produce the observed wide spectrum of brightness inhomogeneities are briefly discussed. (orig.)

An Hα Imaging Survey of the Low-surface-brightness Galaxies Selected from the Fall Sky Region of the 40% ALFALFA H I Survey

Science.gov (United States)

Lei, Feng-Jie; Wu, Hong; Du, Wei; Zhu, Yi-Nan; Lam, Man-I.; Zhou, Zhi-Min; He, Min; Jin, Jun-Jie; Cao, Tian-Wen; Zhao, Pin-Song; Yang, Fan; Wu, Chao-Jian; Li, Hong-Bin; Ren, Juan-Juan

2018-03-01

We present the observed Hα flux and derived star formation rates (SFRs) for a fall sample of low-surface-brightness galaxies (LSBGs). The sample is selected from the fall sky region of the 40% ALFALFA H I Survey–SDSS DR7 photometric data, and all the Hα images were obtained using the 2.16 m telescope, operated by the National Astronomy Observatories, Chinese Academy of Sciences. A total of 111 LSBGs were observed and Hα flux was measured in 92 of them. Though almost all the LSBGs in our sample are H I-rich, their SFRs, derived from the extinction and filter-transmission-corrected Hα flux, are less than 1 M ⊙ yr‑1. LSBGs and star-forming galaxies have similar H I surface densities, but LSBGs have much lower SFRs and SFR surface densities than star-forming galaxies. Our results show that LSBGs deviate from the Kennicutt–Schmidt law significantly, which indicates that they have low star formation efficiency. The SFRs of LSBGs are close to average SFRs in Hubble time and support previous arguments that most of the LSBGs are stable systems and they tend to seldom contain strong interactions or major mergers in their star formation histories.

The effect of bright light on sleepiness among rapid-rotating 12-hour shift workers.

Science.gov (United States)

Sadeghniiat-Haghighi, Khosro; Yazdi, Zohreh; Jahanihashemi, Hassan; Aminian, Omid

2011-01-01

About 20% of workers in industrialized countries are shift workers and more than half of them work on night or rotating shifts. Most night workers complain of sleepiness due to lack of adjustment of the circadian rhythm. In simulated night-work experiments, scheduled exposure to bright light has been shown to reduce these complaints. Our study assessed the effects of bright light exposure on sleepiness during night work in an industrial setting. In a cross-over design, 94 workers at a ceramic factory were exposed to either bright (2500 lux) or normal light (300 lux) during breaks on night shifts. We initiated 20-minute breaks between 24.00 and 02.00 hours. Sleepiness ratings were determined using the Stanford Sleepiness Scale at 22.00, 24.00, 02.00 and 04.00 hours. Under normal light conditions, sleepiness peaked at 02:00 hours. A significant reduction (22% compared to normal light conditions) in sleepiness was observed after workers were exposed to bright light. Exposure to bright light may be effective in reducing sleepiness among night workers.

Global Observations of the 630-nm Nightglow and Patterns of Brightness Measured by ISUAL

Directory of Open Access Journals (Sweden)

Chih-Yu Chiang

2013-01-01

Full Text Available This study investigates the distributions and occurrence mechanisms of the global local-midnight airglow brightness through FORMOSAT-2/ISUAL satellite imaging observations. We focus on the OI 630.0 nm nightglow emission at altitudes of ~250 km along equatorial space. The database used in this study included data from 2007 to 2008 under solar minimum conditions. The data were classified into four specified types in the statistical study. We found that the occurrence of equatorial brightness was often in the vicinity of the geographic equator and mostly at equinoxes with a tendency to move toward the summer hemisphere as the season changes. Conjugate brightness occurring simultaneously on both sides of the geomagnetic equator was observed predominantly in the northern winter. Furthermore, midnight brightness appeared to have lower luminosity from May to July. We suggest that the global midnight brightness associated with the locations and seasons was the result of several effects which include the influence of the thermospheric midnight temperature maximum (MTM, summer-to-winter neutral wind, and ionospheric anomalies.

First insight into dead wood protistan diversity: a molecular sampling of bright-spored Myxomycetes (Amoebozoa, slime-moulds) in decaying beech logs.

Science.gov (United States)

Clissmann, Fionn; Fiore-Donno, Anna Maria; Hoppe, Björn; Krüger, Dirk; Kahl, Tiemo; Unterseher, Martin; Schnittler, Martin

2015-06-01

Decaying wood hosts a large diversity of seldom investigated protists. Environmental sequencing offers novel insights into communities, but has rarely been applied to saproxylic protists. We investigated the diversity of bright-spored wood-inhabiting Myxomycetes by environmental sequencing. Myxomycetes have a complex life cycle culminating in the formation of mainly macroscopic fruiting bodies, highly variable in shape and colour that are often found on decaying logs. Our hypothesis was that diversity of bright-spored Myxomycetes would increase with decay. DNA was extracted from wood chips collected from 17 beech logs of varying decay stages from the Hainich-Dün region in Central Germany. We obtained 260 partial small subunit ribosomal RNA gene sequences of bright-spored Myxomycetes that were assembled into 29 OTUs, of which 65% were less than 98% similar to those in the existing database. The OTU richness revealed by molecular analysis surpassed that of a parallel inventory of fruiting bodies. We tested several environmental variables and identified pH, rather than decay stage, as the main structuring factor of myxomycete distribution. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The globular cluster system of NGC 1316. IV. Nature of the star cluster complex SH2

Science.gov (United States)

Richtler, T.; Husemann, B.; Hilker, M.; Puzia, T. H.; Bresolin, F.; Gómez, M.

2017-05-01

Context. The light of the merger remnant NGC 1316 (Fornax A) is dominated by old and intermediate-age stars. The only sign of current star formation in this big galaxy is the Hii region SH2, an isolated star cluster complex with a ring-like morphology and an estimated age of 0.1 Gyr at a galactocentric distance of about 35 kpc. A nearby intermediate-age globular cluster, surrounded by weak line emission and a few more young star clusters, is kinematically associated. The origin of this complex is enigmatic. Aims: We want to investigate the nature of this star cluster complex. The nebular emission lines permit a metallicity determination which can discriminate between a dwarf galaxy or other possible precursors. Methods: We used the Integral Field Unit (IFU) of the VIMOS instrument at the Very Large Telescope of the European Southern Observatory in high dispersion mode to study the morphology, kinematics, and metallicity employing line maps, velocity maps, and line diagnostics of a few characteristic spectra. Results: The line ratios of different spectra vary, indicating highly structured Hii regions, but define a locus of uniform metallicity. The strong-line diagnostic diagrams and empirical calibrations point to a nearly solar or even super-solar oxygen abundance. The velocity dispersion of the gas is highest in the region offset from the bright clusters. Star formation may be active on a low level. There is evidence for a large-scale disk-like structure in the region of SH2, which would make the similar radial velocity of the nearby globular cluster easier to understand. Conclusions: The high metallicity does not fit to a dwarf galaxy as progenitor. We favour the scenario of a free-floating gaseous complex having its origin in the merger 2 Gyr ago. Over a long period the densities increased secularly until finally the threshold for star formation was reached. SH2 illustrates how massive star clusters can form outside starbursts and without a considerable field

High brightness beams and applications

International Nuclear Information System (INIS)

Sheffield, R.L.

1995-01-01

This paper describes the present research on attaining intense bright electron beams. Thermionic systems are briefly covered. Recent and past results from the photoinjector programs are given. The performance advantages and difficulties presently faced by researchers using photoinjectors is discussed. The progress that has been made in photocathode materials, both in lifetime and quantum efficiency, is covered. Finally, a discussion of emittance measurements of photoinjector systems and how the measurement is complicated by the non-thermal nature of the electron beam is presented

Short Pulse High Brightness X-ray Production with the PLEIADES Thomson Scattering Source

International Nuclear Information System (INIS)

Anderson, S.G.; Barty, C.P.J.; Betts, S.M.; Brown, W.J.; Crane, J.K.; Cross, R.R.; Fittinghoff, D.N.; Gibson, D.J.; Hartemann, F.V.; Kuba, J.; LaSage, G.P.; Rosenzweig, J.B.; Slaughter, D.R.; Springer, P.T.; Tremaine, A.M.

2003-01-01

We describe PLEIADES, a compact, tunable, high-brightness, ultra-short pulse, Thomson x-ray source. The peak brightness of the source is expected to exceed 10 20 photons/s/0.1% bandwidth/mm 2 /mrad 2 . Initial results are reported and compared to theoretical calculations

Two- and 4-hour bright-light exposures differentially effect sleepiness and performance the subsequent night.

Science.gov (United States)

Thessing, V C; Anch, A M; Muehlbach, M J; Schweitzer, P K; Walsh, J K

1994-03-01

The effect of two durations of bright light upon sleepiness and performance during typical night shift hours was assessed. Thirty normal, healthy young adults participated in a 2-night protocol. On the 1st night subjects were exposed to bright or dim light beginning at 2400 hours, under one of the following three conditions: bright light for 4 hours, dim light for 2 hours followed by bright light for 2 hours or dim light for 4 hours. Following light exposure, subjects remained awake until 0800 hours in a dimly lit room and slept in the laboratory between 0800 and 1600 hours, during which time sleep was estimated with actigraphy. Throughout the 2nd night, the multiple sleep latency test (MSLT), simulated assembly line task (SALT) performance, and subjective sleepiness were recorded. The single, 4-hour exposure to bright light was found to significantly increase MSLT scores and improve SALT performance during the early morning hours on the night following bright-light exposure. No significant effects were noted with a 2-hour exposure. The most likely explanation for these findings is a phase delay in the circadian rhythm of sleepiness-alertness.

A new perspective on the infrared brightness temperature ...

Indian Academy of Sciences (India)

CEAWMT), ... temperatures clearly discriminates the cloud pixels of deep convective and ... utilized in the modelling of the histogram of infrared brightness temperature of deep convective and ..... Henderson-Sellers A 1978 Surface type and its effect.

Tolerance of image enhancement brightness and contrast in lateral cephalometric digital radiography for Steiner analysis

Science.gov (United States)

Rianti, R. A.; Priaminiarti, M.; Syahraini, S. I.

2017-08-01

Image enhancement brightness and contrast can be adjusted on lateral cephalometric digital radiographs to improve image quality and anatomic landmarks for measurement by Steiner analysis. To determine the limit value for adjustments of image enhancement brightness and contrast in lateral cephalometric digital radiography for Steiner analysis. Image enhancement brightness and contrast were adjusted on 100 lateral cephalometric radiography in 10-point increments (-30, -20, -10, 0, +10, +20, +30). Steiner analysis measurements were then performed by two observers. Reliabilities were tested by the Interclass Correlation Coefficient (ICC) and significance tested by ANOVA or the Kruskal Wallis test. No significant differences were detected in lateral cephalometric analysis measurements following adjustment of the image enhancement brightness and contrast. The limit value of adjustments of the image enhancement brightness and contrast associated with incremental 10-point changes (-30, -20, -10, 0, +10, +20, +30) does not affect the results of Steiner analysis.

Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

International Nuclear Information System (INIS)

Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, Yoon-Jae; Park, Man-Jin; Moon, Dae Won

2012-01-01

Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m 2 SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

Near-infrared photometry of bright elliptical galaxies

NARCIS (Netherlands)

Peletier, R. F.; Valentijn, E. A.; Jameson, R. F.

High-quality visual-infrared color profiles have been determined for elliptical galaxies for the first time. Surface photometry in J and K is presented for 12 bright elliptical galaxies, and the results have been combined with CCD data in visual passbands. It is shown that the galaxies become bluer

Models of bright storm clouds and related dark ovals in Saturn's Storm Alley as constrained by 2008 Cassini/VIMS spectra

Science.gov (United States)

Sromovsky, L. A.; Baines, K. H.; Fry, P. M.

2018-03-01

A 5° latitude band on Saturn centered near planetocentric latitude 36°S is known as "Storm Alley" because it has been for several extended periods a site of frequent lightning activity and associated thunderstorms, first identified by Porco et al. (2005). The thunderstorms appeared as bright clouds at short and long continuum wavelengths, and over a period of a week or so transformed into dark ovals (Dyudina et al., 2007). The ovals were found to be dark over a wide spectral range, which led Baines et al. (2009) to suggest the possibility that a broadband absorber such as soot produced by lightning could play a significant role in darkening the clouds relative to their surroundings. Here we show that an alternative explanation, which is that the clouds are less reflective because of reduced optical depth, provides an excellent fit to near infrared spectra of similar features obtained by the Cassini Visual and Infrared Mapping Spectrometer (VIMS) in 2008, and leads to a plausible scenario for cloud evolution. We find that the background clouds and the oval clouds are both dominated by the optical properties of a ubiquitous upper cloud layer, which has the same particle size in both regions, but about half the optical depth and physical thickness in the dark oval regions. The dark oval regions are also marked by enhanced emissions in the 5-μm window region, a result of lower optical depth of the deep cloud layer near 3.1-3.8 bar, presumably composed of ammonium hydrosulfide (NH4SH). The bright storm clouds completely block this deep thermal emission with a thick layer of ammonia (NH3) clouds extending from the middle of the main visible cloud layer probably as deep as the 1.7-bar NH3 condensation level. Other condensates might also be present at higher pressures, but are obscured by the NH3 cloud. The strong 3-μm spectral absorption that was displayed by Saturn's Great Storm of 2010-2011 (Sromovsky et al., 2013) is weaker in these storms because the contrast is

Investigating the Bright End of LSST Photometry

Science.gov (United States)

Ojala, Elle; Pepper, Joshua; LSST Collaboration

2018-01-01

The Large Synoptic Survey Telescope (LSST) will begin operations in 2022, conducting a wide-field, synoptic multiband survey of the southern sky. Some fraction of objects at the bright end of the magnitude regime observed by LSST will overlap with other wide-sky surveys, allowing for calibration and cross-checking between surveys. The LSST is optimized for observations of very faint objects, so much of this data overlap will be comprised of saturated images. This project provides the first in-depth analysis of saturation in LSST images. Using the PhoSim package to create simulated LSST images, we evaluate saturation properties of several types of stars to determine the brightness limitations of LSST. We also collect metadata from many wide-field photometric surveys to provide cross-survey accounting and comparison. Additionally, we evaluate the accuracy of the PhoSim modeling parameters to determine the reliability of the software. These efforts will allow us to determine the expected useable data overlap between bright-end LSST images and faint-end images in other wide-sky surveys. Our next steps are developing methods to extract photometry from saturated images.This material is based upon work supported in part by the National Science Foundation through Cooperative Agreement 1258333 managed by the Association of Universities for Research in Astronomy (AURA), and the Department of Energy under Contract No. DE-AC02-76SF00515 with the SLAC National Accelerator Laboratory. Additional LSST funding comes from private donations, grants to universities, and in-kind support from LSSTC Institutional Members.Thanks to NSF grant PHY-135195 and the 2017 LSSTC Grant Award #2017-UG06 for making this project possible.

The seasonal variation in skin hydration, sebum, scaliness, brightness and elasticity in Korean females.

Science.gov (United States)

Nam, G W; Baek, J H; Koh, J S; Hwang, J-K

2015-02-01

Age, gender, regional, and ethnic differences influence skin conditions. The purpose of this study was to observe the effects of environments, especially the air temperature, relative humidity, air pressure, duration of sunshine, and precipitation on skin, and the seasonal variation in skin hydration, sebum, scales, brightness, and elasticity in Korean females. The study included 89 Korean subjects, aged 29.7 ± 6.2 years. The five skin biophysical parameters (skin hydration, sebum, scales, brightness, and elasticity) were measured at six sites: forehead, under the eye, frontal cheek, crow's foot, lateral cheek, and inner forearm. Skin hydration was measured using the Corneometer® CM 825. Skin sebum was measured with Sebumeter® SM 815. Skin scaliness was measured with Visioscan® VC 98. Skin brightness (L* value) was measured by using Spectrophotometer. A suction chamber device, Cutometer® MPA 580, was used to measure the skin elasticity. The measurements were performed every month for 13 months, from April 2007 to April 2008. There were significantly seasonal variations in environmental factors. The air temperature was the lowest in January (-1.7°C), and the highest in August (26.5°C). The relative humidity was the lowest in February (46%), and the highest in July and August (75%). There was a negative correlation between skin scaliness and three environmental factors such as air temperature, relative humidity, and highest precipitation. There was a positive correlation between skin scaliness and two environmental factors such as air pressure and duration of sunshine. Elasticity was correlated with air temperature positively and with air pressure negatively. The correlations shown between the skin biophysical parameters and environmental factors demonstrate that the skin biophysical parameters are affected by environmental factors. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Bright light treatment as add-on therapy for depression in 28 adolescents: a randomized trial.

Science.gov (United States)

Niederhofer, Helmut; von Klitzing, Kai

2011-01-01

In the last decade, a significant incidence of depression in the younger population has been observed. Bright light therapy, an effective therapeutic option for depressed adults, could also provide safe, economical, and effective rapid recovery in adolescents. The randomized trial included 28 inpatients (18 females and 10 males) between 14 and 17 years old with depressive complaints. The study was conducted between February and December of 2010 in Rodewisch, Germany. Half of the patients (n = 14) first received placebo (50 lux) 1 hour a day in the morning from 9:00 am to 10:00 am for 1 week and then received bright light therapy (2,500 lux) for 1 week in the morning from 9:00 am to 10:00 am. The other half (n = 14) first received bright light therapy and then received placebo. Patients were encouraged to continue ongoing treatment (fluoxetine 20 mg/day and 2 sessions of psychotherapy/week) because there were no changes in medication/dosage and psychotherapy since 1 month before the 4-week study period. For assessment of depressive symptoms, the Beck Depression Inventory (BDI) was administered 1 week before and 1 day before placebo treatment, on the day between placebo and bright light treatment, and on the day after and 1 week after bright light treatment. Saliva samples of melatonin and cortisol were collected at 8:00 am and 8:00 pm 1 week before and 1 day before placebo treatment, on the day between placebo and bright light treatment, on the day after bright light treatment, and 1 week after bright light treatment and were assayed for melatonin and cortisol to observe any change in circadian timing. The BDI scores improved significantly (P = .015). The assays of saliva showed significant differences between treatment and placebo for evening melatonin (P = .040). No significant adverse reactions were observed. Antidepressant response to bright light treatment in this age group was statistically superior to placebo. World Health Organization International Clinical

A Region Tracking-Based Vehicle Detection Algorithm in Nighttime Traffic Scenes

Directory of Open Access Journals (Sweden)

Jianqiang Wang

2013-12-01

Full Text Available The preceding vehicles detection technique in nighttime traffic scenes is an important part of the advanced driver assistance system (ADAS. This paper proposes a region tracking-based vehicle detection algorithm via the image processing technique. First, the brightness of the taillights during nighttime is used as the typical feature, and we use the existing global detection algorithm to detect and pair the taillights. When the vehicle is detected, a time series analysis model is introduced to predict vehicle positions and the possible region (PR of the vehicle in the next frame. Then, the vehicle is only detected in the PR. This could reduce the detection time and avoid the false pairing between the bright spots in the PR and the bright spots out of the PR. Additionally, we present a thresholds updating method to make the thresholds adaptive. Finally, experimental studies are provided to demonstrate the application and substantiate the superiority of the proposed algorithm. The results show that the proposed algorithm can simultaneously reduce both the false negative detection rate and the false positive detection rate.

Microwave-heating synthesis and sensing applications of bright gold nanoclusters

Energy Technology Data Exchange (ETDEWEB)

He, Ding-Fei; Xiang, Yang; Wang, Xu [Department of Physics, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China); Yu, Xue-Feng, E-mail: yxf@whu.edu.cn [Department of Physics, Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education and School of Physics and Technology, Wuhan University, Wuhan 430072 (China)

2011-12-15

Highlights: Black-Right-Pointing-Pointer We establish a microwave-heating method to synthesize protein-stabilized Au nanoclusters. Black-Right-Pointing-Pointer The obtained Au nanoclusters show bright red fluorescence. Black-Right-Pointing-Pointer The Au nanoclusters can be used as efficient fluorescence probe for Cu{sup 2+} ion sensing. -- Abstract: A rapid microwave-heating method has been developed for the synthesis of bright Au nanoclusters by using bull serum albumin as the template in an aqueous environment. The reaction time needed is only 7.0 min, and the weight of the products at one batch can reach 15 g. The Au nanoclusters exhibit bright fluorescence at {approx}613 nm with quantum yield of {approx}6.0%. By adjusting the pH value, the products can be controlled to precipitate or re-disperse in aqueous solution. Furthermore, the Au nanoclusters have exhibited high sensitivity and selectivity in the determination of Cu{sup 2+} ions in water. These results suggest an efficient method for obtaining metal nanoclusters for the detection and sensing applications.

Multifrequency radio observations of SNR J0536-6735 (N 59B with associated pulsar

Directory of Open Access Journals (Sweden)

Bozzetto L.M.

2012-01-01

Full Text Available We present a study of new Australian Telescope Compact Array (ATCA observations of supernova remnant, SNR J0536-6735. This remnant appears to follow a shell morphology with a diameter of D=36x29 pc (with 1 pc uncertainty in each direction. There is an embedded HII region on the northern limb of the remnant which made various analysis and measurements (such as flux density, spectral index and polarisation difficult. The radio-continuum emission followed the same structure as the optical emission, allowing for extent and flux density estimates at 20 cm. We estimate the surface brightness at 1 GHz of 2.55x10−21 Wm−2 Hz−1 sr−1 for the SNR. Also, we detect a distinctive radio-continuum point source which confirms the previous suggestion of this remnant being associated with pulsar wind nebula (PWN. The tail of this remnant is not seen in the radio-continuum images and is only seen in the optical and X-ray images.

An open, component-based information infrastructure for integrated health information networks.

Science.gov (United States)

Tsiknakis, Manolis; Katehakis, Dimitrios G; Orphanoudakis, Stelios C

2002-12-18

A fundamental requirement for achieving continuity of care is the seamless sharing of multimedia clinical information. Different technological approaches can be adopted for enabling the communication and sharing of health record segments. In the context of the emerging global information society, the creation of and access to the integrated electronic health record (I-EHR) of a citizen has been assigned high priority in many countries. This requirement is complementary to an overall requirement for the creation of a health information infrastructure (HII) to support the provision of a variety of health telematics and e-health services. In developing a regional or national HII, the components or building blocks that make up the overall information system ought to be defined and an appropriate component architecture specified. This paper discusses current international priorities and trends in developing the HII. It presents technological challenges and alternative approaches towards the creation of an I-EHR, being the aggregation of health data created during all interactions of an individual with the healthcare system. It also presents results from an ongoing Research and Development (R&D) effort towards the implementation of the HII in HYGEIAnet, the regional health information network of Crete, Greece, using a component-based software engineering approach. Critical design decisions and related trade-offs, involved in the process of component specification and development, are also discussed and the current state of development of an I-EHR service is presented. Finally, Human Computer Interaction (HCI) and security issues, which are important for the deployment and use of any I-EHR service, are considered.

Bright-light intervention induces a dose-dependent increase in striatal response to risk in healthy volunteers

DEFF Research Database (Denmark)

Macoveanu, Julian; Fisher, Patrick M; Madsen, Martin K

2016-01-01

Bright-light interventions have successfully been used to reduce depression symptoms in patients with seasonal affective disorder, a depressive disorder most frequently occurring during seasons with reduced daylight availability. Yet, little is known about how light exposure impacts human brain...... function, for instance on risk taking, a process affected in depressive disorders. Here we examined the modulatory effects of bright-light exposure on brain activity during a risk-taking task. Thirty-two healthy male volunteers living in the greater Copenhagen area received 3weeks of bright......-light intervention during the winter season. Adopting a double-blinded dose-response design, bright-light was applied for 30minutes continuously every morning. The individual dose varied between 100 and 11.000lx. Whole-brain functional MRI was performed before and after bright-light intervention to probe how...

Electron Source Brightness and Illumination Semi-Angle Distribution Measurement in a Transmission Electron Microscope.

Science.gov (United States)

Börrnert, Felix; Renner, Julian; Kaiser, Ute

2018-05-21

The electron source brightness is an important parameter in an electron microscope. Reliable and easy brightness measurement routes are not easily found. A determination method for the illumination semi-angle distribution in transmission electron microscopy is even less well documented. Herein, we report a simple measurement route for both entities and demonstrate it on a state-of-the-art instrument. The reduced axial brightness of the FEI X-FEG with a monochromator was determined to be larger than 108 A/(m2 sr V).

A very bright SAR arc: implications for extreme magnetosphere-ionosphere coupling

Directory of Open Access Journals (Sweden)

J. Baumgardner

2008-01-01

Full Text Available In contrast to the polar aurora visible during geomagnetic storms, stable auroral red (SAR arcs offer a sub-visual manifestation of direct magnetosphere-ionosphere (M-I coupling at midlatitudes. The SAR arc emission at 6300 Å is driven by field-aligned magnetospheric energy transport from ring current/plasmapause locations into the ionosphere-thermosphere system. The first SAR arc was observed at the dawn of the space age (1956, and the typical brightness levels and occurrence patterns obtained from subsequent decades of observations appear to be consistent with the downward heat conduction theory, i.e., heated ambient F-layer electrons excite oxygen atoms to produce a spectrally pure emission. On very rare occasions, a SAR arc has been reported to be at brightness levels visible to the naked eye. Here we report on the first case of a very bright SAR arc (~13 kilo-Rayleighs observed by four diagnostic systems that sampled various aspects of the sub-auroral domain near Millstone Hill, MA, on the night of 29 October 1991: an imaging spectrograph, an all-sky camera, an incoherent scatter radar (ISR, and a DMSP satellite. Simulations of emission using the ISR and DMSP data with the MSIS neutral atmosphere succeed in reproducing the brightness levels observed. This provides a robust confirmation of M-I coupling theory in its most extreme aeronomic form within the innermost magnetosphere (L~2 during a rare superstorm event. The unusually high brightness value appears to be due to the rare occurrence of the heating of dense ionospheric plasma just equatorward of the trough/plasmapause location, in contrast to the more typical heating of the less dense F-layer within the trough.

On the Relationship between Star Formation and Activity in Galaxies

Science.gov (United States)

Gonzalez Delgado, Rosa M.

1995-11-01

This thesis is made of three main parts. In the first one a sample of 55 galaxies with an active nucleus (Seyfert 1, Seyfert2 and LINERs) is analysed; these were observed with the 4.2m WHT and 1m JKT in CCD narrow band H-alpha +[NII] and [OIII] to map the distribution of HII regions and the morphology of the circumnuclear extended emission associated with the active nucleus. The analysis of the extended emission and HII regions is carried out, as a function of the level of activity and of the Hubble type. One third of the sample shows circumnuclear HII regions, but only 9% of these are S1. The number surface density of the star forming sites and the location of the brightest HII region, indicates that in S2 the star formation is more important in the inner disk; however, in S1 the distribution of the star forming sites is more uniform with distance, and the brighest HII regions are farther away from the nucleus than in S2. The luminosity function, size distribution, the relationship between the Ha flux and the size, the emission measure, and the radial distribution of the HII regions in 27 out of the 55 galaxies of the sample are studied. This comprises a statistical analysis of more than 2000 HII regions. In the second part of this thesis the giant extragalactic HII region NGC 2363 and the starburst galaxy NGC 7714 are studied; they were observed in narrow band CCD H-alpha image with the JKT and spectroscopically from 3700 to 9600 A with the WHT. Both objects are experiencing intense star formation activity. Evidence of this comes from the detection of WC and WN emission features in NGC 2363 and in NGC 7714 respectively; this suggests an age of the present burst between 3 and 5 Myr. However, evidence for the existence of a previous burst in NGC 7714 comes from the detection of the infrared CaII triplet in absorption. The physical conditions and chemical composition of the gas are derived. In both cases, the metallicity is low (12+log O/H=7.89 for NGC 2363) and

VizieR Online Data Catalog: FIR data of IR-bright dust-obscured galaxies (DOGs) (Toba+, 2017)

Science.gov (United States)

Toba, Y.; Nagao, T.; Wang, W.-H.; Matsuhara, H.; Akiyama, M.; Goto, T.; Koyama, Y.; Ohyama, Y.; Yamamura, I.

2017-11-01

We investigate the star-forming activity of a sample of infrared (IR)-bright dust-obscured galaxies (DOGs) that show an extreme red color in the optical and IR regime, (i-[22])AB>7.0. Combining an IR-bright DOG sample with the flux at 22μm>3.8mJy discovered by Toba & Nagao (2016ApJ...820...46T) with the IRAS faint source catalog version 2 and AKARI far-IR (FIR) all-sky survey bright source catalog version 2, we selected 109 DOGs with FIR data. For a subsample of seven IR-bright DOGs with spectroscopic redshifts (0.07DOGs and (2) the contribution of the active galactic nucleus to IR luminosity increases with IR luminosity. By comparing the stellar mass and SFR relation for our DOG sample and the literature, we found that most of the IR-bright DOGs lie significantly above the main sequence of star-forming galaxies at similar redshift, indicating that the majority of IRAS- or AKARI-detected IR-bright DOGs are starburst galaxies. (1 data file).

Bright luminance from silicon dioxide film with carbon nanotube electron beam exposure

Energy Technology Data Exchange (ETDEWEB)

Lee, Su Woong; Hong, Ji Hwan; Kang, Jung Su; Callixte, Shikili; Park, Kyu Chang, E-mail: kyupark@khu.ac.kr

2016-02-15

We observed the bright bluish-white luminescence with naked eye from carbon nanotube electron beam exposed silicon dioxide (SiO{sub 2}) thin film on Si substrate. The luminescence shows a peak intensity at 2.7 eV (460 nm) with wide spread up to 600 nm after the C-beam exposed on SiO{sub 2} thin film. The C-beam exposure system is composed of carbon nanotube emitters as electron beam source. The brightness strongly depend on the exposure condition. Luminescence characteristic was optimized by C-beam adjustment to observe with the naked eye. The cause of luminescence in the C-beam exposed SiO{sub 2} thin film is analyzed by CL microscopy, FT-IR, AFM and ellipsometer. Decrease of Si–O bonding was observed after C-beam exposure, and this reveals that oxygen deficient defects which are irradiation-sensitive cause 2.7 eV peak of luminescence. - Highlights: • We observed bright luminescence for SiO{sub 2} thin film with naked eye by carbon nanotube electron beam (C-beam) exposure technique. • The bright luminance from C-beam exposed SiO{sub 2} film will open novel silicon optoelectronics.

A Neurocomputational Account of the Role of Contour Facilitation in Brightness Perception

Directory of Open Access Journals (Sweden)

Dražen eDomijan

2015-02-01

Full Text Available A novel filling-in model is proposed in order to account for challenging brightness illusions where inducing background elements are spatially separated from gray target such as dungeon, cube and grating illusion, bull's eye and ring patterns. The model implements simple idea that neural response to low-contrast contour is enhanced (facilitated by the presence of collinear or parallel high-contrast contour in the wider neighborhood. Contour facilitation is achieved via dendritic inhibition which enables computation of maximum function among inputs to the node. Recurrent application of maximum function leads to the propagation of neural signal along collinear or parallel contour segments. When strong global contour signal is accompanied with weak local contour signal at the same location, conditions are met to produce brightness assimilation within filling-in network. Computer simulations showed that the model correctly predicts brightness appearance in all of the above mentioned illusions as well as in White's effect, Benary's cross, Todorović's illusion, checkerboard contrast, contrast-contrast illusion and various variations on the White's effect. The proposed model offer new insights on how geometric factors (contour colinearity or parallelism jointly with contrast magnitude contribute to the brightness perception.

Manakins can produce iridescent and bright feather colours without melanosomes.

Science.gov (United States)

Igic, Branislav; D'Alba, Liliana; Shawkey, Matthew D

2016-06-15

Males of many species often use colourful and conspicuous ornaments to attract females. Among these, male manakins (family: Pipridae) provide classic examples of sexual selection favouring the evolution of bright and colourful plumage coloration. The highly iridescent feather colours of birds are most commonly produced by the periodic arrangement of melanin-containing organelles (melanosomes) within barbules. Melanin increases the saturation of iridescent colours seen from optimal viewing angles by absorbing back-scattered light; however, this may reduce the wide-angle brightness of these signals, contributing to a dark background appearance. We examined the nanostructure of four manakin species (Lepidothrix isidorei, L. iris, L. nattereri and L. coeruleocapilla) to identify how they produce their bright plumage colours. Feather barbs of all four species were characterized by dense and fibrous internal spongy matrices that likely increase scattering of light within the barb. The iridescent, yet pale or whitish colours of L. iris and L. nattereri feathers were produced not by periodically arranged melanosomes within barbules, but by periodic matrices of air and β-keratin within barbs. Lepidothrix iris crown feathers were able to produce a dazzling display of colours with small shifts in viewing geometry, likely because of a periodic nanostructure, a flattened barb morphology and disorder at a microstructural level. We hypothesize that iridescent plumage ornaments of male L. iris and L. nattereri are under selection to increase brightness or luminance across wide viewing angles, which may potentially increase their detectability by females during dynamic and fast-paced courtship displays in dim light environments. © 2016. Published by The Company of Biologists Ltd.

A Brightness-Referenced Star Identification Algorithm for APS Star Trackers

Science.gov (United States)

Zhang, Peng; Zhao, Qile; Liu, Jingnan; Liu, Ning

2014-01-01

Star trackers are currently the most accurate spacecraft attitude sensors. As a result, they are widely used in remote sensing satellites. Since traditional charge-coupled device (CCD)-based star trackers have a limited sensitivity range and dynamic range, the matching process for a star tracker is typically not very sensitive to star brightness. For active pixel sensor (APS) star trackers, the intensity of an imaged star is valuable information that can be used in star identification process. In this paper an improved brightness referenced star identification algorithm is presented. This algorithm utilizes the k-vector search theory and adds imaged stars' intensities to narrow the search scope and therefore increase the efficiency of the matching process. Based on different imaging conditions (slew, bright bodies, etc.) the developed matching algorithm operates in one of two identification modes: a three-star mode, and a four-star mode. If the reference bright stars (the stars brighter than three magnitude) show up, the algorithm runs the three-star mode and efficiency is further improved. The proposed method was compared with other two distinctive methods the pyramid and geometric voting methods. All three methods were tested with simulation data and actual in orbit data from the APS star tracker of ZY-3. Using a catalog composed of 1500 stars, the results show that without false stars the efficiency of this new method is 4∼5 times that of the pyramid method and 35∼37 times that of the geometric method. PMID:25299950

Modeling laser brightness from cross Porro prism resonators

Science.gov (United States)

Forbes, Andrew; Burger, Liesl; Litvin, Igor Anatolievich

2006-08-01

Laser brightness is a parameter often used to compare high power laser beam delivery from various sources, and incorporates both the power contained in the particular mode, as well as the propagation of that mode through the beam quality factor, M2. In this study a cross Porro prism resonator is considered; crossed Porro prism resonators have been known for some time, but until recently have not been modeled as a complete physical optics system that allows the modal output to be determined as a function of the rotation angle of the prisms. In this paper we consider the diffraction losses as a function of the prism rotation angle relative to one another, and combine this with the propagation of the specific modes to determine the laser output brightness as a function of the prism orientation.

The GBT Diffuse Ionized Gas Survey (GDIGS)

Science.gov (United States)

Luisi, Matteo; Anderson, Loren Dean; Liu, Bin; Bania, Thomas; Balser, Dana; Wenger, Trey; Haffner, Lawrence Matthew

2018-01-01

Diffuse ionized gas in the Galactic mid-plane known as the "Warm Ionized Medium" (WIM) makes up ~20% of the gas mass of the Milky Way and >90% of its ionized gas. It is the last major component of the interstellar medium (ISM) that has not yet been studied at high spatial and spectral resolution, and therefore many of its fundamental properties remain unclear. The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) is a new large survey of the Milky Way disk at C-band (4-8 GHz). The main goals of GDIGS are to investigate the properties of the WIM and to determine the connection between the WIM and high-mass star formation over the Galactic longitude and latitude range of 32 deg > l > -5 deg, |b| resolution of 0.5 km/s and rms sensitivities of ~3 mJy per beam. GDIGS observations are currently underway and are expected to be completed by late 2018. These data will allow us to: 1) Study for the first time the inner-Galaxy WIM unaffected by confusion from discrete HII regions, 2) determine the distribution of the inner Galaxy WIM, 3) investigate the ionization state of the WIM, 4) explore the connection between the WIM and HII regions, and 5) analyze the effect of leaked photons from HII regions on ISM dust temperatures.

Brightness distribution data on 2918 radio sources at 365 MHz

International Nuclear Information System (INIS)

Cotton, W.D.; Owen, F.N.; Ghigo, F.D.

1975-01-01

This paper is the second in a series describing the results of a program attempting to fit models of the brightness distribution to radio sources observed at 365 MHz with the Bandwidth Synthesis Interferometer (BSI) operated by the University of Texas Radio Astronomy Observatory. Results for a further 2918 radio sources are given. An unresolved model and three symmetric extended models with angular sizes in the range 10--70 arcsec were attempted for each radio source. In addition, for 348 sources for which other observations of brightness distribution are published, the reference to the observations and a brief description are included

Extreme Ultraviolet Explorer Bright Source List

Science.gov (United States)

Malina, Roger F.; Marshall, Herman L.; Antia, Behram; Christian, Carol A.; Dobson, Carl A.; Finley, David S.; Fruscione, Antonella; Girouard, Forrest R.; Hawkins, Isabel; Jelinsky, Patrick

1994-01-01

Initial results from the analysis of the Extreme Ultraviolet Explorer (EUVE) all-sky survey (58-740 A) and deep survey (67-364 A) are presented through the EUVE Bright Source List (BSL). The BSL contains 356 confirmed extreme ultraviolet (EUV) point sources with supporting information, including positions, observed EUV count rates, and the identification of possible optical counterparts. One-hundred twenty-six sources have been detected longward of 200 A.

Brightness enhancement of plasma ion source by utilizing anode spot for nano applications

Energy Technology Data Exchange (ETDEWEB)

Park, Yeong-Shin; Lee, Yuna; Chung, Kyoung-Jae; Hwang, Y. S. [Department of Nuclear Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of); Kim, Yoon-Jae [Samsung Electronics Co. Ltd., Gyeonggi 445-701 (Korea, Republic of); Park, Man-Jin [Research Institute of Nano Manufacturing System, Seoul National University of Science and Technology, Seoul 139-743 (Korea, Republic of); Moon, Dae Won [Nanobio Fusion Research Center, Korea Research Institute of Standards and Science, Daejeon 305-600 (Korea, Republic of)

2012-02-15

Anode spots are known as additional discharges on positively biased electrode immersed in plasmas. The anode spot plasma ion source (ASPIS) has been investigated as a high brightness ion source for nano applications such as focused ion beam (FIB) and nano medium energy ion scattering (nano-MEIS). The generation of anode spot is found to enhance brightness of ion beam since the anode spot increases plasma density near the extraction aperture. Brightness of the ASPIS has been estimated from measurement of emittance for total ion beam extracted through sub-mm aperture. The ASPIS is installed to the FIB system. Currents and diameters of the focused beams with/without anode spot are measured and compared. As the anode spot is turned on, the enhancement of beam current is observed at fixed diameter of the focused ion beam. Consequently, the brightness of the focused ion beam is enhanced as well. For argon ion beam, the maximum normalized brightness of 12 300 A/m{sup 2} SrV is acquired. The ASPIS is applied to nano-MEIS as well. The ASPIS is found to increase the beam current density and the power efficiency of the ion source for nano-MEIS. From the present study, it is shown that the ASPIS can enhance the performance of devices for nano applications.

High cortisol awakening response is associated with an impairment of the effect of bright light therapy

DEFF Research Database (Denmark)

Martiny, Klaus Per Juul; Lunde, Marianne Anita; Undén, M

2009-01-01

OBJECTIVE: We investigated the predictive validity of the cortisol awakening response (CAR) in patients with non-seasonal major depression. METHOD: Patients were treated with sertraline in combination with bright or dim light therapy for a 5-week period. Saliva cortisol levels were measured in 63...... patients, as an awakening profile, before medication and light therapy started. The CAR was calculated by using three time-points: awakening and 20 and 60 min after awakening. RESULTS: Patients with low CAR had a very substantial effect of bright light therapy compared with dim light therapy, whereas...... patients with a high CAR had no effect of bright light therapy compared with dim light therapy. CONCLUSION: High CAR was associated with an impairment of the effect of bright light therapy. This result raises the question of whether bright light acts through a mechanism different from...

Modelling of Lyman-alpha emitting galaxies and ionized bubbles at the epoch of reionization

Science.gov (United States)

Yajima, Hidenobu; Sugimura, Kazuyuki; Hasegawa, Kenji

2018-04-01

Understanding {Ly{α }} emitting galaxies (LAEs) can be a key to reveal cosmic reionization and galaxy formation in the early Universe. Based on halo merger trees and {Ly{α }} radiation transfer calculations, we model redshift evolution of LAEs and their observational properties at z ≥ 6. We consider ionized bubbles associated with individual LAEs and IGM transmission of {Ly{α }} photons. We find that {Ly{α }} luminosity tightly correlates with halo mass and stellar mass, while the relation with star formation rate has a large dispersion. Comparing our models with the observed luminosity function by Konno et al., we suggest that LAEs at z ˜ 7 have galactic wind of V_out ≳ 100 km s^{-1} and HI column density of N_HI ≳ 10^{20} cm^{-2}. Number density of bright LAEs rapidly decreases as redshift increases, due to both lower star formation rate and smaller HII bubbles. Our model predicts future wide deep surveys with next generation telescopes, such as JWST, E-ELT and TMT, can detect LAEs at z ˜ 10 with a number density of n_LAE ˜ a few × 10^{-6} Mpc^{-3} for the flux sensitivity of 10^{-18} erg cm^{-2} s^{-1}. When giant HII bubbles are formed by clustering LAEs, the number density of observable LAEs can increase by a factor of few. By combining these surveys with future 21-cm observations, it could be possible to detect both LAEs with L_{Lyα }≳ 10^{42} erg s^{-1} and their associated giant HII bubbles with the size ≳ 250 kpc at z ˜ 10.

Nimbus-5 ESMR Polar Gridded Brightness Temperatures, Version 2

Data.gov (United States)

National Aeronautics and Space Administration — The Nimbus-5 Electrically Scanning Microwave Radiometer (ESMR) data set consists of gridded brightness temperature arrays for the Arctic and Antarctic, spanning 11...

Minimum-phase distribution of cosmic source brightness

International Nuclear Information System (INIS)

Gal'chenko, A.A.; Malov, I.F.; Mogil'nitskaya, L.F.; Frolov, V.A.

1984-01-01

Minimum-phase distributions of brightness (profiles) for cosmic radio sources 3C 144 (the wave lambda=21 cm), 3C 338 (lambda=3.5 m), and 3C 353 (labda=31.3 cm and 3.5 m) are obtained. A real possibility for the profile recovery from module fragments of its Fourier-image is shown

The Cluster-Randomized BRIGHT Trial: Proactive Case Finding for Community-Dwelling Older Adults

Science.gov (United States)

Kerse, Ngaire; McLean, Chris; Moyes, Simon A.; Peri, Kathy; Ng, Terence; Wilkinson-Meyers, Laura; Brown, Paul; Latham, Nancy; Connolly, Martin

2014-01-01

PURPOSE People are now living longer, but disability may affect the quality of those additional years of life. We undertook a trial to assess whether case finding reduces disability among older primary care patients. METHODS We conducted a cluster-randomized trial of the Brief Risk Identification Geriatric Health Tool (BRIGHT) among 60 primary care practices in New Zealand, assigning them to an intervention or control group. Intervention practices sent a BRIGHT screening tool to older adults every birthday; those with a score of 3 or higher were referred to regional geriatric services for assessment and, if needed, service provision. Control practices provided usual care. Main outcomes, assessed in blinded fashion, were residential care placement and hospitalization, and secondary outcomes were disability, assessed with Nottingham Extended Activities of Daily Living Scale (NEADL), and quality of life, assessed with the World Health Organization Quality of Life scale, abbreviated version (WHOQOL-BREF). RESULTS All 8,308 community-dwelling patients aged 75 years and older were approached; 3,893 (47%) participated, of whom 3,010 (77%) completed the trial. Their mean age was 80.3 (SD 4.5) years, and 55% were women. Overall, 88% of the intervention group returned a BRIGHT tool; 549 patients were referred. After 36 months, patients in the intervention group were more likely than those in the control group to have been placed in residential care: 8.4% vs 6.2% (hazard ratio = 1.32; 95% CI, 1.04–1.68; P = .02). Intervention patients had smaller declines in mean scores for physical health-related quality of life (1.6 vs 2.9 points, P = .007) and psychological health-related quality of life (1.1 vs 2.4 points, P = .005). Hospitalization, disability, and use of services did not differ between groups, however. CONCLUSIONS Our case-finding strategy was effective in increasing identification of older adults with disability, but there was little evidence of improved outcomes

An Octave/MATLAB® Interface for Rapid Processing of SMOS L1C Full Polarization Brightness Temperature

Directory of Open Access Journals (Sweden)

Pablo Saavedra

2018-01-01

Full Text Available A tool to process the SMOS microwave radiometer level 1C polarized brightness temperatures data product has been developed. The SMOS L1C science product contains the dual and full (Stokes vector polarization brightness temperatures at L-band for multiple incidence angles. In order to use the L1C product, the measurements are processed by a number of procedures including radio frequency interference (RFI filters, conversion of the polarization plane from the antenna (X- & Y-pol to the Earth’s surface frame (H- & V-pol, and averaging to fixed classes of incidence angles. The software allows for the processing of data for the entire daily half-orbit product, or for specific regions of interest, and can be adapted as a bash-job to process a large number of data files e.g. for time series analysis. This paper describes the tool which was developed in GNU C++ with the capability to be compiled as MEX function to work with Octave or MATLAB® without any source code adjustment. Funding statement: 'Deutsche Forschungsgemeinschaft' DFG under grant number SI 606/24-1.

Availability of color calibration for consistent color display in medical images and optimization of reference brightness for clinical use

Science.gov (United States)

Iwai, Daiki; Suganami, Haruka; Hosoba, Minoru; Ohno, Kazuko; Emoto, Yutaka; Tabata, Yoshito; Matsui, Norihisa

2013-03-01

Color image consistency has not been accomplished yet except the Digital Imaging and Communication in Medicine (DICOM) Supplement 100 for implementing a color reproduction pipeline and device independent color spaces. Thus, most healthcare enterprises could not check monitor degradation routinely. To ensure color consistency in medical color imaging, monitor color calibration should be introduced. Using simple color calibration device . chromaticity of colors including typical color (Red, Green, Blue, Green and White) are measured as device independent profile connection space value called u'v' before and after calibration. In addition, clinical color images are displayed and visual differences are observed. In color calibration, monitor brightness level has to be set to quite lower value 80 cd/m2 according to sRGB standard. As Maximum brightness of most color monitors available currently for medical use have much higher brightness than 80 cd/m2, it is not seemed to be appropriate to use 80 cd/m2 level for calibration. Therefore, we propose that new brightness standard should be introduced while maintaining the color representation in clinical use. To evaluate effects of brightness to chromaticity experimentally, brightness level is changed in two monitors from 80 to 270cd/m2 and chromaticity value are compared with each brightness levels. As a result, there are no significant differences in chromaticity diagram when brightness levels are changed. In conclusion, chromaticity is close to theoretical value after color calibration. Moreover, chromaticity isn't moved when brightness is changed. The results indicate optimized reference brightness level for clinical use could be set at high brightness in current monitors .

Polarization and brightness of the blazar S5 0716+714 in 1991-2004

Science.gov (United States)

Doroshenko, V. T.; Kiselev, N. N.

2017-06-01

We investigate the photometric and polarimetric behavior of the blazar S5 0716+714 based on the observations carried out in 1991-2004 at the 125-cm Crimean Astrophysical Observatory telescope (AZT11) with a photopolarimeter that allows simultaneous polarization and brightness measurements to be made in the U BV RI bands. We also provide the U BV photometry for the blazar obtained in 2000-2009 with a 60-cm telescope at the Crimean Station of the Sternberg Astronomical Institute. The pattern of flux variability and the correlation between the brightness, color, and polarization variations have been investigated. In this time interval the blazar showed a significant brightness and polarization variability similar to noise processes.

Bright breathers in nonlinear left-handed metamaterial lattices

Science.gov (United States)

Koukouloyannis, V.; Kevrekidis, P. G.; Veldes, G. P.; Frantzeskakis, D. J.; DiMarzio, D.; Lan, X.; Radisic, V.

2018-02-01

In the present work, we examine a prototypical model for the formation of bright breathers in nonlinear left-handed metamaterial lattices. Utilizing the paradigm of nonlinear transmission lines, we build a relevant lattice and develop a quasi-continuum multiscale approximation that enables us to appreciate both the underlying linear dispersion relation and the potential for bifurcation of nonlinear states. We focus here, more specifically, on bright discrete breathers which bifurcate from the lower edge of the linear dispersion relation at wavenumber k=π . Guided by the multiscale analysis, we calculate numerically both the stable inter-site centered and the unstable site-centered members of the relevant family. We quantify the associated stability via Floquet analysis and the Peierls-Nabarro barrier of the energy difference between these branches. Finally, we explore the dynamical implications of these findings towards the potential mobility or lack thereof (pinning) of such breather solutions.

High-brightness electron beams for production of high intensity, coherent radiation for scientific and industrial applications

International Nuclear Information System (INIS)

Kim, K.-J.

1999-01-01

Relativistic electron beams with high six-dimensional phase space densities, i.e., high-brightness beams, are the basis for efficient generation of intense and coherent radiation beams for advanced scientific and industrial applications. The remarkable progress in synchrotrons radiation facilities from the first generation to the current, third-generation capability illustrates this point. With the recent development of the high-brightness electron gun based on laser-driven rf photocathodes, linacs have become another important option for high-brightness electron beams. With linacs of about 100 MeV, megawatt-class infrared free-electron lasers can be designed for industrial applications such as power beaming. With linacs of about 10 GeV, 1- angstrom x-ray beams with brightness and time resolution exceeding by several orders of magnitude the current synchrotrons radiation sources can be generated based on self-amplified spontaneous emission. Scattering of a high-brightness electron beam by high power laser beams is emerging as a compact method of generating short-pulse, bright x-rays. In the high-energy frontier, photons of TeV quantum energy could be generated by scattering laser beams with TeV electron beams in future linear colliders

Star formation in the outskirts of disk galaxies

NARCIS (Netherlands)

Ferguson, AMN

2002-01-01

The far outer regions of galactic disks allow an important probe of both star formation and galaxy formation. I discuss how observations of HII regions in these low gas density, low metallicity environments can shed light on the physical processes which drive galactic star formation. The history of

A case study on large-scale dynamical influence on bright band using cloud radar during the Indian summer monsoon

Science.gov (United States)

Jha, Ambuj K.; Kalapureddy, M. C. R.; Devisetty, Hari Krishna; Deshpande, Sachin M.; Pandithurai, G.

2018-02-01

The present study is a first of its kind attempt in exploring the physical features (e.g., height, width, intensity, duration) of tropical Indian bright band using a Ka-band cloud radar under the influence of large-scale cyclonic circulation and attempts to explain the abrupt changes in bright band features, viz., rise in the bright band height by 430 m and deepening of the bright band by about 300 m observed at around 14:00 UTC on Sep 14, 2016, synoptically as well as locally. The study extends the utility of cloud radar to understand how the bright band features are associated with light precipitation, ranging from 0 to 1.5 mm/h. Our analysis of the precipitation event of Sep 14-15, 2016 shows that the bright band above (below) 3.7 km, thickness less (more) than 300 m can potentially lead to light drizzle of 0-0.25 mm/h (drizzle/light rain) at the surface. It is also seen that the cloud radar may be suitable for bright band study within light drizzle limits than under higher rain conditions. Further, the study illustrates that the bright band features can be determined using the polarimetric capability of the cloud radar. It is shown that an LDR value of - 22 dB can be associated with the top height of bright band in the Ka-band observations which is useful in the extraction of the bright band top height and its width. This study is useful for understanding the bright band phenomenon and could be potentially useful in establishing the bright band-surface rain relationship through the perspective of a cloud radar, which would be helpful to enhance the cloud radar-based quantitative estimates of precipitation.

H2O Megamasers toward Radio-bright Seyfert 2 Nuclei

Science.gov (United States)

Zhang, J. S.; Liu, Z. W.; Henkel, C.; Wang, J. Z.; Coldwell, G. V.

2017-02-01

Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H2O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 (z ˜ 0.0448), was detected four times during our observations, with a typical maser flux density of ˜30 mJy and a corresponding (very large) luminosity of ˜1135 L ⊙. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H2O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H2O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies. Based on observations with the 100 m telescope of the MPIfR (Max-Planck-Institut für Radioastronomie) at Effelsberg.

Massive stars, x-ray ridge, and galactic 26Al gamma-ray line emission

International Nuclear Information System (INIS)

Montmerle, T.

1986-07-01

Massive stars interact with their parent molecular cloud by means of their ionizing flux and strong winds, thereby creating giant, hollow HII regions. To account for the observed structure of these HII regions, it appears necessary that all the wind energy be dissipated. Dorland and Montmerle have recently proposed a new dissipation mechanism, in the process, diffuse hard X-rays are emitted. If the observed galactic X-ray ''ridge'' results from this process on a galactic scale, it can be accounted for by the interaction of ∼3000 Wolf-Rayet stars (mostly within a ∼6.5 kpc ring) with their surrounding interstellar gas. This result is essentially consistent with the suggestion by Prantzos and Casse that the galactic 26 Al γ-ray line emission originates in Wolf-Rayet stars

Bright-light exposure during daytime sleeping affects nocturnal melatonin secretion after simulated night work.

Science.gov (United States)

Nagashima, Shunsuke; Osawa, Madoka; Matsuyama, Hiroto; Ohoka, Wataru; Ahn, Aemi; Wakamura, Tomoko

2018-02-01

The guidelines for night and shift workers recommend that after night work, they should sleep in a dark environment during the daytime. However, staying in a dark environment during the daytime reduces nocturnal melatonin secretion and delays its onset. Daytime bright-light exposure after night work is important for melatonin synthesis the subsequent night and for maintaining the circadian rhythms. However, it is not clear whether daytime sleeping after night work should be in a dim- or a bright-light environment for maintaining melatonin secretion. The aim of this study, therefore, was to evaluate the effect of bright-light exposure during daytime sleeping on nocturnal melatonin secretion after simulated night work. Twelve healthy male subjects, aged 24.8 ± 4.6 (mean ± SD), participated in 3-day sessions under two experimental conditions, bright light or dim light, in a random order. On the first day, the subjects entered the experimental room at 16:00 and saliva samples were collected every hour between 18:00 and 00:00 under dim-light conditions. Between 00:00 and 08:00, they participated in tasks that simulated night work. At 10:00 the next morning, they slept for 6 hours under either a bright-light condition (>3000 lx) or a dim-light condition (night work were compared between the light conditions using paired t-tests. The ANOVA results indicated a significant interaction (light condition and3 day) (p = .006). Post hoc tests indicated that in the dim-light condition, the melatonin concentration was significantly lower on the second day than on the first day (p = .046); however, in the bright-light condition, there was no significant difference in the melatonin concentration between the days (p = .560). There was a significant difference in ΔDLMO between the conditions (p = .015): DLMO after sleeping was advanced by 11.1 ± 17.4 min under bright-light conditions but delayed for 7.2 ± 13.6 min after sleeping under dim-light conditions. No

Characterizing the microstructural basis of “unidentified bright objects” in neurofibromatosis type 1 : A combined in vivo multicomponent T2 relaxation and multi-shell diffusion MRI analysis

NARCIS (Netherlands)

Billiet, T.; Mädler, B.; D'Arco, F.; Deprez, S.; Plasschaert, E.; Leemans, A.; Zhang, H.; Van Den Bergh, B.R.H.; Vandenbulcke, M.; Legius, E.; Sunaert, S.; Emsell, L.

2014-01-01

Introduction The histopathological basis of “unidentified bright objects” (UBOs) (hyperintense regions seen on T2-weighted magnetic resonance (MR) brain scans in neurofibromatosis-1 (NF1)) remains unclear. New in vivo MRI-based techniques (multi-exponential T2 relaxation (MET2) and diffusion MR

Bright infrared LEDs based on colloidal quantum-dots

KAUST Repository

Sun, Liangfeng; Choi, Joshua J.; Stachnik, David; Bartnik, Adam C.; Hyun, Byung-Ryool; Malliaras, George G.; Hanrath, Tobias; Wise, Frank W.

2013-01-01

Record-brightness infrared LEDs based on colloidal quantum-dots have been achieved through control of the spacing between adjacent quantum-dots. By tuning the size of quantum-dots, the emission wavelengths can be tuned between 900nm and 1650nm. © 2013 Materials Research Society.

Human phase response curve to a 1 h pulse of bright white light

Science.gov (United States)

St Hilaire, Melissa A; Gooley, Joshua J; Khalsa, Sat Bir S; Kronauer, Richard E; Czeisler, Charles A; Lockley, Steven W

2012-01-01

The phase resetting response of the human circadian pacemaker to light depends on the timing of exposure and is described by a phase response curve (PRC). The current study aimed to construct a PRC for a 1 h exposure to bright white light (∼8000 lux) and to compare this PRC to a dim background light PRC. These data were also compared to a previously completed 6.7 h bright white light PRC and a dim background light PRC constructed under similar conditions. Participants were randomized for exposure to 1 h of either bright white light (n= 18) or dim background light (n= 18) scheduled at 1 of 18 circadian phases. Participants completed constant routine (CR) procedures in dim light (light exposure to assess circadian phase. Phase shifts were calculated as the difference in timing of dim light melatonin onset (DLMO) during pre- and post-stimulus CRs. Exposure to 1 h of bright white light induced a Type 1 PRC with a fitted peak-to-trough amplitude of 2.20 h. No discernible PRC was observed in the dim background light PRC. The fitted peak-to-trough amplitude of the 1 h bright light PRC was ∼40% of that for the 6.7 h PRC despite representing only 15% of the light exposure duration, consistent with previous studies showing a non-linear duration–response function for the effects of light on circadian resetting. PMID:22547633

Massive Star Formation: Accreting from Companion X. Chen1 ...

Indian Academy of Sciences (India)

Abstract. We report the possible accretion from companion in the mas- sive star forming region (G350.69–0.49). This region seems to be a binary system composed of a diffuse object (possible nebulae or UC HII region) and a Massive Young Stellar Object (MYSO) seen in Spitzer IRAC image. The diffuse object and MYSO ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... We report the possible accretion from companion in the massive star forming region (G350.69–0.49). This region seems to be a binary system composed of a diffuse object (possible nebulae or UC HII region) and a Massive Young Stellar Object (MYSO) seen in Spitzer IRAC image. The diffuse object and ...

Critical issues in enhancing brightness in thin film phosphors for flat-panel display applications

International Nuclear Information System (INIS)

Singh, R.K.; Chen, Z.; Kumar, D.; Cho, K.; Ollinger, M.

2002-01-01

Thin film phosphors have potential applications in field emission flat-panel displays. However, they are limited by the lower cathodoluminescent brightness in comparison to phosphor powders. In this paper, we have investigated the critical parameters that need to be optimized to increase the brightness of phosphor thin films. Specifically, we studied the role of surface roughness and optical properties of the substrate on the brightness of the phosphor films. Thin Y 2 O 3 :Eu phosphor films were deposited on various substrates (lanthanum aluminate, quartz, sapphire, and silicon) with thicknesses varying from 50 to 500 nm. A model that accounts for diffuse and specular or scattering effects has been developed to understand the effects of the microstructure on the emission characteristics of the cathodoluminescent films. The results from the model show that both the optical properties of the substrate and the surface roughness of the films play a critical role in controlling the brightness of laser deposited phosphor films

Detecting stellar-wind bubbles through infrared arcs in H II regions

Science.gov (United States)

Mackey, Jonathan; Haworth, Thomas J.; Gvaramadze, Vasilii V.; Mohamed, Shazrene; Langer, Norbert; Harries, Tim J.

2016-02-01

Mid-infrared arcs of dust emission are often seen near ionizing stars within H II regions. A possible explanations for these arcs is that they could show the outer edges of asymmetric stellar wind bubbles. We use two-dimensional, radiation-hydrodynamics simulations of wind bubbles within H II regions around individual stars to predict the infrared emission properties of the dust within the H II region. We assume that dust and gas are dynamically well-coupled and that dust properties (composition, size distribution) are the same in the H II region as outside it, and that the wind bubble contains no dust. We post-process the simulations to make synthetic intensity maps at infrared wavebands using the torus code. We find that the outer edge of a wind bubble emits brightly at 24 μm through starlight absorbed by dust grains and re-radiated thermally in the infrared. This produces a bright arc of emission for slowly moving stars that have asymmetric wind bubbles, even for cases where there is no bow shock or any corresponding feature in tracers of gas emission. The 24 μm intensity decreases exponentially from the arc with increasing distance from the star because the dust temperature decreases with distance. The size distribution and composition of the dust grains has quantitative but not qualitative effects on our results. Despite the simplifications of our model, we find good qualitative agreement with observations of the H II region RCW 120, and can provide physical explanations for any quantitative differences. Our model produces an infrared arc with the same shape and size as the arc around CD -38°11636 in RCW 120, and with comparable brightness. This suggests that infrared arcs around O stars in H II regions may be revealing the extent of stellar wind bubbles, although we have not excluded other explanations.

An Unusual Transient in the Extremely Metal-Poor Galaxy SDSS J094332.35+332657.6 (Leoncino Dwarf)

Science.gov (United States)

Filho, Mercedes E.; Sánchez Almeida, J.

2018-05-01

We have serendipitously discovered that Leoncino Dwarf, an ultra-faint, low-metallicity record-holder dwarf galaxy, may have hosted a transient source, and possibly exhibited a change in morphology, a shift in the center of brightness, and peak variability of the main (host) source in images taken approximately 40 yr apart; it is highly likely that these phenomena are related. Scenarios involving a Solar System object, a stellar cluster, dust enshrouding, and accretion variability have been considered, and discarded, as the origin of the transient. Although a combination of time-varying strong and weak lensing effects, induced by an intermediate mass black hole (104 - 5 × 105 M⊙) moving within the Milky Way halo (0.1 - 4 kpc), can conceivably explain all of the observed variable galaxy properties, it is statistically highly unlikely according to current theoretical predictions, and, therefore, also discarded. A cataclysmic event such as a supernova/hypernova could have occurred, as long as the event was observed towards the later/late-stage descent of the light curve, but this scenario fails to explain the absence of a post-explosion source and/or host HII region in recent optical images. An episode related to the giant eruption of a luminous blue variable star, a stellar merger or a nova, observed at, or near, peak magnitude may explain the transient source and possibly the change in morphology/center of brightness, but can not justify the main source peak variability, unless stellar variability is evoked.

Operational Bright-Band Snow Level Detection Using Doppler Radar

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — A method to detect the bright-band snow level from radar reflectivity and Doppler vertical velocity data collection with an atmospheric profiling Doppler radar. The...

The formation and disintegration of magnetic bright points observed by sunrise/IMaX

Energy Technology Data Exchange (ETDEWEB)

Utz, D.; Del Toro Iniesta, J. C.; Bellot Rubio, L. R. [Instituto de Astrofísica de Andalucía (CSIC), Apdo. de Correos 3004, E-18080 Granada (Spain); Jurčák, J. [Astronomical Institute, Academy of Sciences of the Czech Republic, 251 65 Ondřejov (Czech Republic); Martínez Pillet, V. [Instituto de Astrofísica de Canarias, Vía Láctea, s/n, E-38200 La Laguna (Spain); Solanki, S. K. [Max-Planck Institut für Sonnensystemforschung, Max-Planck-Strasse, 2, D-37191 (Germany); Schmidt, W., E-mail: utz@iaa.es, E-mail: dominik.utz@uni-graz.at [Kiepenheuer-Institut für Sonnenphysik, Schöneckstrasse 6, D-79104 Freiburg (Germany)

2014-12-01

related spatially and temporally to these downflows. The paper is complemented by a detailed discussion of aspects regarding the applied methods, the complementary literature, and in depth analysis of parameters like magnetic field strength and velocity distributions. An important difference to magnetic elements and associated bright structures in active region plage is that most of the quiet Sun bright points display significant downflows over a large fraction of their lifetime (i.e., in more than 46% of time instances/measurements they show downflows exceeding 1 km s{sup –1}).

High brightness photonic band crystal semiconductor lasers in the passive mode locking regime

International Nuclear Information System (INIS)

Rosales, R.; Kalosha, V. P.; Miah, M. J.; Bimberg, D.; Posilović, K.; Pohl, J.; Weyers, M.

2014-01-01

High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm −2  sr −1 are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.

Nonautonomous discrete bright soliton solutions and interaction management for the Ablowitz-Ladik equation.

Science.gov (United States)

Yu, Fajun

2015-03-01

We present the nonautonomous discrete bright soliton solutions and their interactions in the discrete Ablowitz-Ladik (DAL) equation with variable coefficients, which possesses complicated wave propagation in time and differs from the usual bright soliton waves. The differential-difference similarity transformation allows us to relate the discrete bright soliton solutions of the inhomogeneous DAL equation to the solutions of the homogeneous DAL equation. Propagation and interaction behaviors of the nonautonomous discrete solitons are analyzed through the one- and two-soliton solutions. We study the discrete snaking behaviors, parabolic behaviors, and interaction behaviors of the discrete solitons. In addition, the interaction management with free functions and dynamic behaviors of these solutions is investigated analytically, which have certain applications in electrical and optical systems.

Improving the laser brightness of a commercial laser system

Science.gov (United States)

Naidoo, Darryl; Litvin, Igor; Forbes, Andrew

2016-02-01

We investigate the selection of a flat-top beam and a Gaussian beam inside a laser cavity on opposing mirrors. The concept is tested external to the laser cavity in a single pass and double pass regime where the latter mimics a single round trip in the laser. We implement this intra-cavity selection through the use of two 16 level diffractive optical elements. We consider a solid-state diode side-pumped laser resonator in a typical commercial laser configuration that consists of two planar mirrors where the DOEs are positioned at the mirrors. We out couple the Gaussian and flat-top distributions and we show that we improve the brightness of the laser with active mode control. We also demonstrate that the quality of the beam transformations determine the brightness improvement.

Recent advances in high-brightness electron guns at AES

International Nuclear Information System (INIS)

Bluem, H.; Todd, A.M.M.; Cole, M.D.; Rathke, J.; Schultheiss, T.

2003-01-01

We describe a number of active Advanced Energy Systems projects pertaining to the development of advanced, high-brightness electron guns for various applications. These projects include a fully superconducting, CW RF gun, nearing test, that utilizes the niobium surface as the photocathode material. An integrated 100 mA, low emittance DC/SRF gun, ideal as an injector for ERL-type light sources and intended as the injector for a 100 kW FEL, is in late design stage. A parallel high-power, CW, normal-conducting L-band RF gun project has just begun. The early performance analysis for this gun also shows good promise as an injector for ERL-type light sources. Lastly, a fully axisymmetric RF gun, operating in X-band, is being studied as a source of extremely bright electron bunches

Modular Zero Energy. BrightBuilt Home

Energy Technology Data Exchange (ETDEWEB)

Aldrich, Robb [Steven Winter Associates, Inc., Norwalk, CT (United States); Butterfield, Karla [Steven Winter Associates, Inc., Norwalk, CT (United States)

2016-03-01

With funding from the Building America Program, part of the U.S. Department of Energy Building Technologies Office, the Consortium for Advanced Residential Buildings (CARB) worked with BrightBuilt Home (BBH) to evaluate and optimize building systems. CARB’s work focused on a home built by Black Bros. Builders in Lincolnville, Maine (International Energy Conservation Code Climate Zone 6). As with most BBH projects to date, modular boxes were built by Keiser Homes in Oxford, Maine.

High-brightness high-order harmonic generation at 13 nm with a long gas jet

International Nuclear Information System (INIS)

Kim, Hyung Taek; Kim, I Jong; Lee, Dong Gun; Park, Jong Ju; Hong, Kyung Han; Nam, Chang Hee

2002-01-01

The generation of high-order harmonics is well-known method producing coherent extreme-ultraviolet radiation with pulse duration in the femtosecond regime. High-order harmonics have attracted much attention due to their unique features such as coherence, ultrashort pulse duration, and table-top scale system. Due to these unique properties, high-order harmonics have many applications of atomic and molecular spectroscopy, plasma diagnostics and solid-state physics. Bright generation of high-order harmonics is important for actual applications. Especially, the generation of strong well-collimated harmonics at 13 nm can be useful for the metrology of EUV lithography optics because of the high reflectivity of Mo-Si mirrors at this wavelength. The generation of bright high-order harmonics is rather difficult in the wavelength region below 15nm. Though argon and xenon gases have large conversion efficiency, harmonic generation from these gases is restricted to wavelengths over 20 nm due to low ionization potential. Hence, we choose neon for the harmonic generation around 13 nm; it has larger conversion efficiency than helium and higher ionization potential than argon. In this experiment, we have observed enhanced harmonic generation efficiency and low beam divergence of high-order harmonics from a elongated neon gas jet by the enhancement of laser propagation in an elongated gas jet. A uniform plasma column was produced when the gas jet was exposed to converging laser pulses.

Quantitative Image Restoration in Bright Field Optical Microscopy.

Science.gov (United States)

Gutiérrez-Medina, Braulio; Sánchez Miranda, Manuel de Jesús

2017-11-07

Bright field (BF) optical microscopy is regarded as a poor method to observe unstained biological samples due to intrinsic low image contrast. We introduce quantitative image restoration in bright field (QRBF), a digital image processing method that restores out-of-focus BF images of unstained cells. Our procedure is based on deconvolution, using a point spread function modeled from theory. By comparing with reference images of bacteria observed in fluorescence, we show that QRBF faithfully recovers shape and enables quantify size of individual cells, even from a single input image. We applied QRBF in a high-throughput image cytometer to assess shape changes in Escherichia coli during hyperosmotic shock, finding size heterogeneity. We demonstrate that QRBF is also applicable to eukaryotic cells (yeast). Altogether, digital restoration emerges as a straightforward alternative to methods designed to generate contrast in BF imaging for quantitative analysis. Copyright © 2017 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Infrared profile of Milky Way at 2.4 μm

International Nuclear Information System (INIS)

Hayakawa, S.; Ito, K.; Matsumoto, T.; Ono, T.; Uyama, K.

1976-01-01

A balloon observation was made of infrared radiation from the Milky Way at wavelength 2.4 μm, with a band width of 0.1 μm, avoiding intense OH airglow. The telescope employed is described. The optical system was cooled by liquid N 2 to reduce the background thermal radiation and improve the detector sensitivity. An array of three PbS detectors was employed. An isophoto of the infrared surface brightness is shown. It appeared that some infrared sources are associated with objects in the spiral arms, but a considerable fraction of these sources is distributed over the galaxy in a similar manner to normal stars. An analysis of the results suggests that the infrared radiation observed at 2.4 μm is emitted mainly from the region inside the solar circle. A comparison was made with the intensity of 100 MeV γ-rays, produced by collisions of cosmic rays with interstellar matter. The longitude dependences observed for the 2.4 μm radiation, the 2.6 mm CO line, HII regions, the 21 cm H line, and the 100 MeV γ-rays correlated with one another. It is concluded that infrared emission provides a further means of investigating galactic structure. (U.K.)

High Excitation Gas and ISM

Science.gov (United States)

Peeters, E.; Martin-Hernandez, N. L.; Rodriguez-Fernandez, N. J.; Tielens, A. G. G. M.

2004-01-01

An overview is given of ISO results on regions of high excitation ISM and gas, i.e. HII regions, the Galactic Centre and Supernovae Remnants. IR emission due to fine-structure lines, molecular hydrogen, silicates, polycyclic aromatic hydrocarbons and dust are summarized, their diagnostic capabilities illustrated and their implications highlighted.

Colors and Photometry of Bright Materials on Vesta as Seen by the Dawn Framing Camera

Science.gov (United States)

Schroeder, S. E.; Li, J.-Y.; Mittlefehldt, D. W.; Pieters, C. M.; De Sanctis, M. C.; Hiesinger, H.; Blewett, D. T.; Russell, C. T.; Raymond, C. A.; Keller, H. U.;

Observations of copolar correlation coefficient through a bright band at vertical incidence

Science.gov (United States)

Zrnic, D. S.; Raghavan, R.; Chandrasekar, V.

1994-01-01

This paper discusses an application of polarimetric measurements at vertical incidence. In particular, the correlation coefficients between linear copolar components are examined, and measurements obtained with the National Severe Storms Laboratory (NSSL)'s and National Center for Atmospheric Research (NCAR)'s polarimetric radars are presented. The data are from two well-defined bright bands. A sharp decrease of the correlation coefficient, confined to a height interval of a few hundred meters, marks the bottom of the bright band.

H{sub 2}O Megamasers toward Radio-bright Seyfert 2 Nuclei

Energy Technology Data Exchange (ETDEWEB)

Zhang, J. S.; Liu, Z. W. [Center for Astrophysics, Guangzhou University, Guangzhou, 510006 (China); Henkel, C. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Wang, J. Z. [Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Coldwell, G. V., E-mail: jszhang@gzhu.edu.cn [FCEFyN-UNSJ-CONICET, San Juan (Argentina)

2017-02-20

Using the Effelsberg-100 m telescope, we perform a successful pilot survey on H{sub 2}O maser emission toward a small sample of radio-bright Seyfert 2 galaxies with a redshift larger than 0.04. The targets were selected from a large Seyfert 2 sample derived from the spectroscopic Sloan Digital Sky Survey Data Release 7 (SDSS-DR7). One source, SDSS J102802.9+104630.4 ( z ∼ 0.0448), was detected four times during our observations, with a typical maser flux density of ∼30 mJy and a corresponding (very large) luminosity of ∼1135 L {sub ⊙}. The successful detection of this radio-bright Seyfert 2 and an additional tentative detection support our previous statistical results that H{sub 2}O megamasers tend to arise from Seyfert 2 galaxies with large radio luminosity. The finding provides further motivation for an upcoming larger H{sub 2}O megamaser survey toward Seyfert 2s with particularly radio-bright nuclei with the basic goal to improve our understanding of the nuclear environment of active megamaser host galaxies.

Water-soluble multidentate polymers compactly coating Ag2S quantum dots with minimized hydrodynamic size and bright emission tunable from red to second near-infrared region.

Science.gov (United States)

Gui, Rijun; Wan, Ajun; Liu, Xifeng; Yuan, Wen; Jin, Hui

2014-05-21

Hydrodynamic size-minimized quantum dots (QDs) have outstanding physicochemical properties for applications in multicolor molecular and cellular imaging at the level of single molecules and nanoparticles. In this study, we have reported the aqueous synthesis of Ag2S QDs by using thiol-based multidentate polymers as capping reagents. By regulating the composition of the precursors (AgNO3 and sulfur-N2H4·H2O complex) and multidentate polymers (poly(acrylic acid)-graft-cysteamine-graft-ethylenediamine), as well as the reaction time, Ag2S QDs (2.6-3.7 nm) are prepared, displaying tunable photoluminescence (PL) emission from red to the second near-infrared region (687-1096 nm). The small hydrodynamic thickness (1.6-1.9 nm) of the multidentate polymers yields a highly compact coating for the QDs, which results in the bright fluorescent QDs with high PL quantum yields (QYs: 14.2-16.4%). Experimental results confirm that the QDs have high PL stability and ultralow cytotoxicity, as well as high PLQYs and small hydrodynamic sizes (4.5-5.6 nm) similar to fluorescent proteins (27-30 kDa), indicating the feasibility of highly effective PL imaging in cells and living animals.

The morphology and surface brightness of extragalactic jets

International Nuclear Information System (INIS)

Bicknell, G.V.

1983-01-01

The problems associated with laminar flow models are reviewed, and an analogy between laboratory jets and astrophysical jets is given. The relationship between surface brightness and the jet full width half maximum is not in general as predicted by simple magnetohydrodynamic models. An alternative turbulent model is presented

Bright and photostable nitrogen-vacancy fluorescence from unprocessed detonation nanodiamond.

Science.gov (United States)

Reineck, P; Capelli, M; Lau, D W M; Jeske, J; Field, M R; Ohshima, T; Greentree, A D; Gibson, B C

2017-01-05

Bright and photostable fluorescence from nitrogen-vacancy (NV) centers is demonstrated in unprocessed detonation nanodiamond particle aggregates. The optical properties of these particles is analyzed using confocal fluorescence microscopy and spectroscopy, time resolved fluorescence decay measurements, and optically detected magnetic resonance experiments. Two particle populations with distinct optical properties are identified and compared to high-pressure high-temperature (HPHT) fluorescent nanodiamonds. We find that the brightness of one detonation nanodiamond particle population is on the same order as that of highly processed fluorescent 100 nm HPHT nanodiamonds. Our results may open the path to a simple and up-scalable route for the production of fluorescent NV nanodiamonds for use in bioimaging applications.

High brightness photonic band crystal semiconductor lasers in the passive mode locking regime

Energy Technology Data Exchange (ETDEWEB)

Rosales, R.; Kalosha, V. P.; Miah, M. J.; Bimberg, D. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany); Posilović, K. [Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany); PBC Lasers GmbH, Hardenbergstrasse 36, 10623 Berlin (Germany); Pohl, J.; Weyers, M. [Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Str. 4, Berlin 12489 (Germany)

2014-10-20

High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm{sup −2} sr{sup −1} are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.

SMOS brightness temperature assimilation into the Community Land Model

Directory of Open Access Journals (Sweden)

D. Rains

2017-11-01

Full Text Available SMOS (Soil Moisture and Ocean Salinity mission brightness temperatures at a single incident angle are assimilated into the Community Land Model (CLM across Australia to improve soil moisture simulations. Therefore, the data assimilation system DasPy is coupled to the local ensemble transform Kalman filter (LETKF as well as to the Community Microwave Emission Model (CMEM. Brightness temperature climatologies are precomputed to enable the assimilation of brightness temperature anomalies, making use of 6 years of SMOS data (2010–2015. Mean correlation R with in situ measurements increases moderately from 0.61 to 0.68 (11 % for upper soil layers if the root zone is included in the updates. A reduced improvement of 5 % is achieved if the assimilation is restricted to the upper soil layers. Root-zone simulations improve by 7 % when updating both the top layers and root zone, and by 4 % when only updating the top layers. Mean increments and increment standard deviations are compared for the experiments. The long-term assimilation impact is analysed by looking at a set of quantiles computed for soil moisture at each grid cell. Within hydrological monitoring systems, extreme dry or wet conditions are often defined via their relative occurrence, adding great importance to assimilation-induced quantile changes. Although still being limited now, longer L-band radiometer time series will become available and make model output improved by assimilating such data that are more usable for extreme event statistics.

Restoration and Enhancement of Underwater Images Based on Bright Channel Prior

Directory of Open Access Journals (Sweden)

Yakun Gao

2016-01-01

Full Text Available This paper proposed a new method of underwater images restoration and enhancement which was inspired by the dark channel prior in image dehazing field. Firstly, we proposed the bright channel prior of underwater environment. By estimating and rectifying the bright channel image, estimating the atmospheric light, and estimating and refining the transmittance image, eventually underwater images were restored. Secondly, in order to rectify the color distortion, the restoration images were equalized by using the deduced histogram equalization. The experiment results showed that the proposed method could enhance the quality of underwater images effectively.

The visibility of galaxies as a function of central surface brightness

International Nuclear Information System (INIS)

Disney, M.; Phillipps, S.

1983-01-01

The likelihood of a galaxy with given intrinsic profile appearing in a photograph catalogue with limiting criteria on apparent magnitude and angular size will depend on the maximum distance at which such a galaxy can lie and still obey both criteria. It is demonstrated that the corresponding volume in which the galaxy will be visible is a sensitive function of the galaxy's central surface brightness as well as its absolute magnitude. Before the observed concentrations around preferred values of surface brightness can be regarded as real, it will be necessary to make allowance for this selection effect. (author)

Optical Observations of X-ray Bright, Optically Normal Galaxies

Science.gov (United States)

Sadun, Alberto C.; Aryan, N. S.; Ghosh, K. K.

2007-05-01

X-ray bright, optically normal galaxies (XBONGs) are galaxies that seem to have normal spectra and morphology, but are relatively bright x-ray sources. The large ratio of the x-ray to optical emission suggests that some activity, similar to that of active galactic nuclei (AGN), is occurring. Since the galaxies do not show any obvious sign of nuclear activity in their optical spectra, one possible explanation is that these galaxies do not have an optically thick accretion disk at small radii, as previously assumed. Previous data for NGC 7626 classifies it as an XBONG, and so we are studying optical features of this galaxy in order to determine better its features. After confirming an x-ray jet, we are now comparing this to optical features that we have found, including warped dust lanes and a possible optical jet.

High-brightness tapered laser diodes with photonic crystal structures

Science.gov (United States)

Li, Yi; Du, Weichuan; Kun, Zhou; Gao, Songxin; Ma, Yi; Tang, Chun

2018-02-01

Beam quality of tapered laser diodes is limited by higher order lateral mode. On purpose of optimizing the brightness of tapered laser diodes, we developed a novel design of tapered diodes. This devices based on InGaAs/AlGaAs asymmetry epitaxial structure, containing higher order lateral mode filtering schemes especially photonic crystal structures, which fabricated cost effectively by using standard photolithography and dry etch processes. Meanwhile, the effects of photonic crystal structures on mode control are also investigated theoretically by FDBPM (Finite-Difference Beam Propagation Method) calculation. We achieved a CW optical output power of 6.9W at 940nm for a single emitter with 4 mm cavity length. A nearly diffraction limited beam of M2 ≍1.9 @ 0.5W has been demonstrated, and a highest brightness of β =75MW/(cm2 ·sr) was reached.

The limit values for brightness and contrast adjustment in digital panoramic radiography

Science.gov (United States)

Zahra, A. T.; Syahraini, S. I.; Kiswanjaya, B.; Ustriyana, P.

2017-08-01

There is an overall lack of studies about digital panoramic radiography. The application of image enhancement techniques is still being done based on the operator’s preferences, since there is no objective limitation. The aim is to evaluate the limit values of the brightness and contrast adjustment in digital panoramic radiography. Digital panoramic radiographs were divided into three groups (dark, medium, and light), and the contrast and brightness adjustments were done using Digora for Windows. The static evaluations were done using three criteria: 1 if the image had lower quality, 2 if there was no difference and 3 if the image had better quality. The radiographic changes differed in each group depending on the initial imaging conditions. The brightness adjustment limit values in the dark and medium groups were -10 and +20, respectively, and -20 and +10 in the light group. The contrast adjustment limit values in all of the groups were -10 and +10.

SeaWinds - Oceans, Land, Polar Regions

Science.gov (United States)

1999-01-01

The SeaWinds scatterometer on the QuikScat satellite makes global radar measurements -- day and night, in clear sky and through clouds. The radar data over the oceans provide scientists and weather forecasters with information on surface wind speed and direction. Scientists also use the radar measurements directly to learn about changes in vegetation and ice extent over land and polar regions.This false-color image is based entirely on SeaWinds measurements obtained over oceans, land, and polar regions. Over the ocean, colors indicate wind speed with orange as the fastest wind speeds and blue as the slowest. White streamlines indicate the wind direction. The ocean winds in this image were measured by SeaWinds on September 20, 1999. The large storm in the Atlantic off the coast of Florida is Hurricane Gert. Tropical storm Harvey is evident as a high wind region in the Gulf of Mexico, while farther west in the Pacific is tropical storm Hilary. An extensive storm is also present in the South Atlantic Ocean near Antarctica.The land image was made from four days of SeaWinds data with the aid of a resolution enhancement algorithm developed by Dr. David Long at Brigham Young University. The lightest green areas correspond to the highest radar backscatter. Note the bright Amazon and Congo rainforests compared to the dark Sahara desert. The Amazon River is visible as a dark line running horizontally though the bright South American rain forest. Cities appear as bright spots on the images, especially in the U.S. and Europe.The image of Greenland and the north polar ice cap was generated from data acquired by SeaWinds on a single day. In the polar region portion of the image, white corresponds to the largest radar return, while purple is the lowest. The variations in color in Greenland and the polar ice cap reveal information about the ice and snow conditions present.NASA's Earth Science Enterprise is a long-term research and technology program designed to examine Earth

ORIGIN OF THE DIFFUSE, FAR ULTRAVIOLET EMISSION IN THE INTERARM REGIONS OF M101

International Nuclear Information System (INIS)

Crocker, Alison F.; Chandar, Rupali; Calzetti, Daniela; Holwerda, Benne Willem; Leitherer, Claus; Popescu, Cristina; Tuffs, R. J.

2015-01-01

We present images from the Solar Blind Channel on the Hubble Space Telescope that resolve hundreds of far-ultraviolet (FUV) emitting stars in two ∼1 kpc 2 interarm regions of the grand-design spiral M101. The luminosity functions of these stars are compared with predicted distributions from simple star formation histories, and are best reproduced when the star formation rate has recently declined (past 10–50 Myr). This pattern is consistent with stars forming within spiral arms and then streaming into the interarm regions. We measure the diffuse FUV surface brightness after subtracting all of the detected stars, clusters, and background galaxies. A residual flux is found for both regions, which can be explained by a mix of stars below our detection limit and scattered FUV light. The amount of scattered light required is much larger for the region immediately adjacent to a spiral arm, a bright source of FUV photons

IRAS variables as galactic structure tracers - Classification of the bright variables

Science.gov (United States)

Allen, L. E.; Kleinmann, S. G.; Weinberg, M. D.

1993-01-01

The characteristics of the 'bright infrared variables' (BIRVs), a sample consisting of the 300 brightest stars in the IRAS Point Source Catalog with IRAS variability index VAR of 98 or greater, are investigated with the purpose of establishing which of IRAS variables are AGB stars (e.g., oxygen-rich Miras and carbon stars, as was assumed by Weinberg (1992)). Results of the analysis of optical, infrared, and microwave spectroscopy of these stars indicate that, out of 88 stars in the BIRV sample identified with cataloged variables, 86 can be classified as Miras. Results of a similar analysis performed for a color-selected sample of stars, using the color limits employed by Habing (1988) to select AGB stars, showed that, out of 52 percent of classified stars, 38 percent are non-AGB stars, including H II regions, planetary nebulae, supergiants, and young stellar objects, indicating that studies using color-selected samples are subject to misinterpretation.

What is a melody? On the relationship between pitch and brightness of timbre.

Science.gov (United States)

Cousineau, Marion; Carcagno, Samuele; Demany, Laurent; Pressnitzer, Daniel

2013-01-01

Previous studies showed that the perceptual processing of sound sequences is more efficient when the sounds vary in pitch than when they vary in loudness. We show here that sequences of sounds varying in brightness of timbre are processed with the same efficiency as pitch sequences. The sounds used consisted of two simultaneous pure tones one octave apart, and the listeners' task was to make same/different judgments on pairs of sequences varying in length (one, two, or four sounds). In one condition, brightness of timbre was varied within the sequences by changing the relative level of the two pure tones. In other conditions, pitch was varied by changing fundamental frequency, or loudness was varied by changing the overall level. In all conditions, only two possible sounds could be used in a given sequence, and these two sounds were equally discriminable. When sequence length increased from one to four, discrimination performance decreased substantially for loudness sequences, but to a smaller extent for brightness sequences and pitch sequences. In the latter two conditions, sequence length had a similar effect on performance. These results suggest that the processes dedicated to pitch and brightness analysis, when probed with a sequence-discrimination task, share unexpected similarities.

Brightness checkerboard lattice method for the calibration of the coaxial reverse Hartmann test

Science.gov (United States)

Li, Xinji; Hui, Mei; Li, Ning; Hu, Shinan; Liu, Ming; Kong, Lingqin; Dong, Liquan; Zhao, Yuejin

2018-01-01

The coaxial reverse Hartmann test (RHT) is widely used in the measurement of large aspheric surfaces as an auxiliary method for interference measurement, because of its large dynamic range, highly flexible test with low frequency of surface errors, and low cost. And the accuracy of the coaxial RHT depends on the calibration. However, the calibration process remains inefficient, and the signal-to-noise ratio limits the accuracy of the calibration. In this paper, brightness checkerboard lattices were used to replace the traditional dot matrix. The brightness checkerboard method can reduce the number of dot matrix projections in the calibration process, thus improving efficiency. An LCD screen displayed a brightness checkerboard lattice, in which the brighter checkerboard and the darker checkerboard alternately arranged. Based on the image on the detector, the relationship between the rays at certain angles and the photosensitive positions of the detector coordinates can be obtained. And a differential de-noising method can effectively reduce the impact of noise on the measurement results. Simulation and experimentation proved the feasibility of the method. Theoretical analysis and experimental results show that the efficiency of the brightness checkerboard lattices is about four times that of the traditional dot matrix, and the signal-to-noise ratio of the calibration is significantly improved.

Evaluations of the new LiF-scintillator and optional brightness enhancement films for neutron imaging

Energy Technology Data Exchange (ETDEWEB)

Iikura, H., E-mail: Iikura.hiroshi@jaea.go.jp [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki (Japan); Tsutsui, N. [Chichibu Fuji Co., Ltd., Ogano, Chichibu, Saitama 368-0193 (Japan); Nakamura, T.; Katagiri, M.; Kureta, M. [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki (Japan); Kubo, J. [Nissan Motor Co., Ltd., Atsugi, Kanagawa 243-0126 (Japan); Matsubayashi, M. [Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki (Japan)

2011-09-21

Japan Atomic Energy Agency has developed the neutron scintillator jointly with Chichibu Fuji Co., Ltd. In this study, we evaluated the new ZnS(Ag):Al/{sup 6}Li scintillator developed for neutron imaging. It was confirmed that the brightness increased by about double while maintaining equal performance for the spatial resolution as compared with a conventional scintillator. High frame-rate imaging using a high-speed video camera system and this new scintillator made it possible to image beyond 10 000 frames per second while still having enough brightness. This technique allowed us to obtain a high-frame-rate visualization of oil flow in a running car engine. Furthermore, we devised a technique to increase the light intensity of reception for a camera by adding brightness enhancement films on the output surface of the scintillator. It was confirmed that the spatial resolution degraded more than double, but the brightness increased by about three times.

Illuminating Low Surface Brightness Galaxies with the Hyper Suprime-Cam Survey

Science.gov (United States)

Greco, Johnny P.; Greene, Jenny E.; Strauss, Michael A.; Macarthur, Lauren A.; Flowers, Xzavier; Goulding, Andy D.; Huang, Song; Kim, Ji Hoon; Komiyama, Yutaka; Leauthaud, Alexie; Leisman, Lukas; Lupton, Robert H.; Sifón, Cristóbal; Wang, Shiang-Yu

2018-04-01

We present a catalog of extended low surface brightness galaxies (LSBGs) identified in the Wide layer of the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP). Using the first ∼200 deg2 of the survey, we have uncovered 781 LSBGs, spanning red (g ‑ i ≥ 0.64) and blue (g ‑ i r eff = 2.″5–14″), our sample is likely dominated by low-redshift objects. We define LSBGs to have mean surface brightnesses {\\bar{μ }}eff}(g)> 24.3 mag arcsec‑2, which allows nucleated galaxies into our sample. As a result, the central surface brightness distribution spans a wide range of μ 0(g) = 18–27.4 mag arcsec‑2, with 50% and 95% of galaxies fainter than 24.3 and 22 mag arcsec‑2, respectively. Furthermore, the surface brightness distribution is a strong function of color, with the red distribution being much broader and generally fainter than that of the blue LSBGs, and this trend shows a clear correlation with galaxy morphology. Red LSBGs typically have smooth light profiles that are well characterized by single-component Sérsic functions. In contrast, blue LSBGs tend to have irregular morphologies and show evidence for ongoing star formation. We cross-match our sample with existing optical, H I, and ultraviolet catalogs to gain insight into the physical nature of the LSBGs. We find that our sample is diverse, ranging from dwarf spheroidals and ultradiffuse galaxies in nearby groups to gas-rich irregulars to giant LSB spirals, demonstrating the potential of the HSC-SSP to provide a truly unprecedented view of the LSBG population.

Numerical simulations of novel high-power high-brightness diode laser structures

Science.gov (United States)

Boucke, Konstantin; Rogg, Joseph; Kelemen, Marc T.; Poprawe, Reinhart; Weimann, Guenter

2001-07-01

One of the key topics in today's semiconductor laser development activities is to increase the brightness of high-power diode lasers. Although structures showing an increased brightness have been developed specific draw-backs of these structures lead to a still strong demand for investigation of alternative concepts. Especially for the investigation of basically novel structures easy-to-use and fast simulation tools are essential to avoid unnecessary, cost and time consuming experiments. A diode laser simulation tool based on finite difference representations of the Helmholtz equation in 'wide-angle' approximation and the carrier diffusion equation has been developed. An optimized numerical algorithm leads to short execution times of a few seconds per resonator round-trip on a standard PC. After each round-trip characteristics like optical output power, beam profile and beam parameters are calculated. A graphical user interface allows online monitoring of the simulation results. The simulation tool is used to investigate a novel high-power, high-brightness diode laser structure, the so-called 'Z-Structure'. In this structure an increased brightness is achieved by reducing the divergency angle of the beam by angular filtering: The round trip path of the beam is two times folded using internal total reflection at surfaces defined by a small index step in the semiconductor material, forming a stretched 'Z'. The sharp decrease of the reflectivity for angles of incidence above the angle of total reflection leads to a narrowing of the angular spectrum of the beam. The simulations of the 'Z-Structure' indicate an increase of the beam quality by a factor of five to ten compared to standard broad-area lasers.

Strategies for the design of bright upconversion nanoparticles for bioanalytical applications

Science.gov (United States)

Wiesholler, Lisa M.; Hirsch, Thomas

2018-06-01

In recent years upconversion nanoparticles (UCNPs) received great attention because of their outstanding optical properties. Especially in bioanalytical applications this class of materials can overcome limitations of common probes like high background fluorescence or blinking. Nevertheless, the requirements for UCNPs to be applicable in biological samples, e.g. small size, water-dispersibility, excitation at low power density are in contradiction with the demand of high brightness. Therefore, a lot of attention is payed to the enhancement of the upconversion luminescence. This review discuss the recent trends and strategies to boost the brightness of UCNPs, classified in three main directions: a) improving the efficiency of energy absorption by the sensitizer via coupling to plasmonic or photonic structures or via attachment of ligands for light harvesting; b) minimizing non-radiative deactivation by variations in the architecture of UCNPs; and c) changing the excitation wavelength to get bright particles at low excitation power density for applications in aqueous systems. These strategies are critically reviewed including current limitations as well as future perspectives for the design of efficient UCNPs especially for sensing application in biological samples or cells.

Direct measurements of the 160.01-min oscillation in the solar radio brightness

International Nuclear Information System (INIS)

Efanov, V.A.; Moiseev, I.G.; Nesterov, N.S.

1983-01-01

Direct (nondifferential) brightness measurements of the quiet sun at lambda = 8.2 and 13.5 mm, corrected by the Bouguer law for absorption in the terrestrial atmosphere, confirm the presence of a 160.009 +- 0.002 min periodicity. At the two wavelengths the relative amplitudes are roughly-equal0.6 x 10 -3 , 1 x 10 -3 . Maximum radio brightness occurs at the phase when optical data indicate the photosphere radius is largest

Trials of bright light exposure and melatonin administration in a patient with non-24 hour sleep-wake syndrome.

Science.gov (United States)

Hayakawa, T; Kamei, Y; Urata, J; Shibui, K; Ozaki, S; Uchiyama, M; Okawa, M

1998-04-01

We report a patient with non-24 h sleep-wake syndrome (non-24) whose free-running sleep-wake cycle was successfully treated with both scheduled bright light exposure and melatonin treatment. In the present study, morning bright light as well as evening melatonin phase-advanced sleep-wake cycles and melatonin rhythm. Both these procedures achieved appropriate entrainment to a 24 h day. However, the patient did not continue morning bright light therapy after the discharge. Rising at appropriate times in the morning for bright light therapy was difficult for him to continue. Melatonin treatment was better tolerated because of its ease of application.

Descartes region - Evidence for Copernican-age volcanism.

Science.gov (United States)

Head, J. W., III; Goetz, A. F. H.

1972-01-01

A model that suggests that the high-albedo central region of the Descartes Formation was formed by Copernican-age volcanism was developed from Orbiter photography, Apollo 12 multispectral photography, earth-based spectrophotometry, and thermal IR and radar data. The bright surface either is abundant in centimeter-sized rocks or is formed from an insulating debris layer overlying a surface with an abundance of rocks in the 1- to 20-cm size range. On the basis of these data, the bright unit is thought to be a young pyroclastic deposit mantling older volcanic units of the Descartes Formation. Since the Apollo 16 target point is only 50 km NW of the central part of this unit, evidence for material associated with this unique highland formation should be searched for in returned soil and rock samples.

PAH EMISSION AT THE BRIGHT LOCATIONS OF PDRs: THE grandPAH HYPOTHESIS

International Nuclear Information System (INIS)

Andrews, H.; Tielens, A. G. G. M.; Boersma, C.; Allamandola, L. J.; Werner, M. W.; Livingston, J.

2015-01-01

The polycyclic aromatic hydrocarbon (PAH) emission observed in the Spitzer Infrared Spectrograph spectra of bright mid-IR locations of NGC 7023, NGC 2023, and NGC 1333 was analyzed. These objects show large variations in PAH band ratios when studied through spectral mapping. Nevertheless, the mid-IR spectra at these bright spots show a remarkably similar PAH emission. We used the NASA Ames PAH IR Spectroscopic Database to fit the observations and analyze the derived PAH populations. Our results show that PAH emission in the 5–15 μm range appears to be rather insensitive to variations of the radiation field. Similar PAH populations of neutral small to medium-sized PAHs (∼50%), with ionized species contributing in slightly less than 50%, provide very good fits. Analyzing the degeneracy of the results shows that subtle (but intrinsic) variations in the emission properties of individual PAHs lead to observable differences in the resulting spectra. On top of this, we found that variations of <30% in the PAH abundances would lead to noticeable spectral differences between the three photodissociation regions (PDRs). Therefore, PAH populations must be remarkably similar at these different lines of sight. To account for this, we suggest the concept of grandPAHs as a unique mixture of the most stable PAHs emitting at these spots. Using NGC 7023 as an example, the grandPAHs refer to the robust PAH population that results from the intense processing of PAHs at the border limit between the PDR and the molecular cloud, where, due to the UV radiation that destroys the PAH population, the abundance of PAHs starts decreasing as we move toward the star

PAH EMISSION AT THE BRIGHT LOCATIONS OF PDRs: THE grandPAH HYPOTHESIS

Energy Technology Data Exchange (ETDEWEB)

Andrews, H.; Tielens, A. G. G. M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands); Boersma, C.; Allamandola, L. J. [NASA Ames Research Center, MS 245-6, Moffett Field, CA 94035 (United States); Werner, M. W.; Livingston, J., E-mail: heandrew@strw.leidenuniv.nl, E-mail: Christiaan.Boersma@nasa.gov [Jet Propulsion Laboratory, MC 264-767, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States)

2015-07-01

The polycyclic aromatic hydrocarbon (PAH) emission observed in the Spitzer Infrared Spectrograph spectra of bright mid-IR locations of NGC 7023, NGC 2023, and NGC 1333 was analyzed. These objects show large variations in PAH band ratios when studied through spectral mapping. Nevertheless, the mid-IR spectra at these bright spots show a remarkably similar PAH emission. We used the NASA Ames PAH IR Spectroscopic Database to fit the observations and analyze the derived PAH populations. Our results show that PAH emission in the 5–15 μm range appears to be rather insensitive to variations of the radiation field. Similar PAH populations of neutral small to medium-sized PAHs (∼50%), with ionized species contributing in slightly less than 50%, provide very good fits. Analyzing the degeneracy of the results shows that subtle (but intrinsic) variations in the emission properties of individual PAHs lead to observable differences in the resulting spectra. On top of this, we found that variations of <30% in the PAH abundances would lead to noticeable spectral differences between the three photodissociation regions (PDRs). Therefore, PAH populations must be remarkably similar at these different lines of sight. To account for this, we suggest the concept of grandPAHs as a unique mixture of the most stable PAHs emitting at these spots. Using NGC 7023 as an example, the grandPAHs refer to the robust PAH population that results from the intense processing of PAHs at the border limit between the PDR and the molecular cloud, where, due to the UV radiation that destroys the PAH population, the abundance of PAHs starts decreasing as we move toward the star.

The Feasibility of Using the BrightHearts Biofeedback-Assisted Relaxation Application for the Management of Pediatric Procedural Pain: A Pilot Study.

Science.gov (United States)

Burton, Karen L O; Morrow, Angela M; Beswick, Brooke V; Khut, George P

2018-04-17

The objective of this pilot study was to assess the acceptability and feasibility of using BrightHearts, a biofeedback-assisted relaxation application (app), in children undergoing painful procedures. Thirty children 7 to 18 years of age undergoing a medical procedure (peripheral blood collection, botulinum toxin injection, or intravenous cannula insertion) participated. Participants used BrightHearts, a heart rate-controlled biofeedback-assisted relaxation training app delivered via an iPad with heart rate measured through a pulse oximeter worn on the ear or thumb. Feasibility was assessed through observations and patient, parent/carer, and healthcare professional feedback. Patient, parent/carer, and healthcare professional satisfaction with BrightHearts was rated using investigator-developed surveys. Eighty-three percent of child participants reported that they found BrightHearts helpful during the procedure and that they would use BrightHearts again. All parents and 96% of healthcare professionals indicated they would use BrightHearts again. Sixty-four percent of healthcare providers perceived that BrightHearts assisted with the ease of performing the procedure. Qualitative analyses found 2 themes: (1) BrightHearts calms through providing distraction and biofeedback and (2) the impact of BrightHearts on the procedure. This pilot study demonstrates the feasibility of using biofeedback-assisted relaxation delivered via the BrightHearts app in children undergoing peripheral blood collection and cannulation. Future studies are required to evaluate BrightHearts' efficacy in reducing pain and anxiety during painful procedures and distinguish the effects of a biofeedback-mediated app from distraction. © 2018 World Institute of Pain.

VizieR Online Data Catalog: Bubble HII region Sh2-39 (N5) (Duronea+, 2017)

Science.gov (United States)

Duronea, N. U.; Cappa, C. E.; Bronfman, L.; Borissova, J.; Gromadzki, M.; Kuhn, M. A.

2017-06-01

The molecular observations were carried out in August 2015 with the 10m Atacama Submillimeter Telescope Experiment (ASTE). We used DASH345, a two sideband single-polarization heterodyne receiver, tunable in LO frequency range from 327GHz to 370GHz at observable frequency range from 321GHz to 376GHz. The XF digital spectrometer was set to a bandwidth and spectral resolution of 128MHz and 125KHz, respectively. The spectral velocity resolution was 0.11km/s, the half power beamwidth (HPBW) is ~22", and the main beam efficiency (mb) is 0.65. Observations were made using the on-the-fly (OTF) mode with two orthogonal scan directions along RA and Dec. (J2000) centered on RA, Dec.(J2000)= (18:17:02.1, -18:40:19). We observed simultaneously the lines CO(3-2) (345.796GHz) and HCO+(4-3) (356.734) in a region of ~17'x17' (see Fig. 1). The spectra were reduced with NOSTAR2 using the standard procedure. The brightest star projected at the center of [BDS2003] 6 (2MASS J18165113-1841488) was observed on August 2016 with Astronomy Research using the Cornell Infra Red Imaging Spectrograph (ARCoIRIS), a cross-dispersed, single-object, longslit, infrared imaging spectrograph,mounted on Blanco 4-m Telescope, CTIO. The spectra cover a simultaneous wavelength range of 0.80 to 2.47um, at a spectral resolution of about 3500 λ{δλ, encompassing the entire zYJHK photometric range. The spectrum was taken with 480 sec integration time, at 1.03 average airmass. The HD163336 telluric A0 V standard is observed immediately after target. The basic steps of the reduction procedure are described in Chene et al. (2012A&A...545A..54C, Cat. J/A+A/545/A54, 2013A&A...549A..98C). We used the corresponding pipeline. (3 data files).

Inversion methods for analysis of neutron brightness measurements in tokamaks

International Nuclear Information System (INIS)

Gorini, G.; Gottardi, N.

1990-02-01

The problem of determining neutron emissivity from neutron brightness measurements in magnetic fusion plasmas is addressed. In the case of two-dimensional measurements with two orthogonal cameras, a complete, tomographic analysis of the data can in principle be performed. The results depend critically on the accuracy of the measurements and alternative solutions can be sought under the assumption of a known emissivity topology (Generalized Abel Inversion). In this work, neutron brightness data from the JET tokamak have been studied with both methods. We find that with the present experimental uncertainty (levels 10-20%) the Abel inversion method works best, while two-dimensional information cannot in general be deduced. This is confirmed by studies of the error propagation in the inversion using artificial data, which are also presented here. An important application of emissivity profile information is the determination of the plasma deuterium temperature profile, T D (R). Results are presented here from the analysis of JET data and the errors in T D (R) are discussed in some detail. It is found that, for typical JET plasma conditions, the dominant source of uncertainty arises from the high plasma impurity level and the fact that it is poorly known; these problems can be expected to be remedied and neutron brightness measurements would be expected to be very effective (especially in high density plasmas) as a T D (R) diagnostics. (author)

Next generation diode lasers with enhanced brightness

Science.gov (United States)

Ried, S.; Rauch, S.; Irmler, L.; Rikels, J.; Killi, A.; Papastathopoulos, E.; Sarailou, E.; Zimer, H.

2018-02-01

High-power diode lasers are nowadays well established manufacturing tools in high power materials processing, mainly for tactile welding, surface treatment and cladding applications. Typical beam parameter products (BPP) of such lasers range from 30 to 50 mm·mrad at several kilowatts of output power. TRUMPF offers a product line of diode lasers to its customers ranging from 150 W up to 6 kW of output power. These diode lasers combine high reliability with small footprint and high efficiency. However, up to now these lasers are limited in brightness due to the commonly used spatial and coarse spectral beam combining techniques. Recently diode lasers with enhanced brightness have been presented by use of dense wavelength multiplexing (DWM). In this paper we report on TRUMPF's diode lasers utilizing DWM. We demonstrate a 2 kW and a 4 kW system ideally suited for fine welding and scanner welding applications. The typical laser efficiency is in the range of 50%. The system offers plug and play exchange of the fiber beam delivery cable, multiple optical outputs and integrated cooling in a very compact package. An advanced control system offers flexible integration in any customer's shop floor environment and includes industry 4.0 capabilities (e.g. condition monitoring and predictive maintenance).

Optical variability of the medium-bright quasar sample

International Nuclear Information System (INIS)

Huang, K.; Mitchell, K.J.; Usher, P.D.

1990-01-01

A variability study of the 32-member Medium-Bright Quasar Sample is reported. It is found that the star US 1953 has undergone a noticeable variation in the course of 26 hr. Apparent variations in the extragalactic object US 3498 may be illusory, owing to its partially resolved appearance. No other evidence for variability was detected. 34 refs

Night Sky Brightness Measurement by the Public through a Mobile Phone App

Science.gov (United States)

Kamegai, Kazuhisa; Tsukada, Ken; Inoue, Hiroki

2015-08-01

The darkness of night sky is important naturally for astronomy researchers, and also for the public people. Particularly, it is meaningful for those who begin to have an interest in gazing stars. Some previous studies suggest that light pollution may affect human health and ecosystem in various ways. Furthermore, it causes a lot of waste of electric energy for lighting.In Japan, the night sky brightness had been measured by Ministry of Environment for a few decades. Recently some global efforts have been also conducted. However the number of measured position is limited because the measurement needs some apparatus and takes long time.Here we show a result of quick and easy measurements of night sky brightness by the public people through a mobile phone app. The measurements were conducted in cooperation between some members of the Tenpla project and a weather forecasting company. The app has been developed by the company and has been installed by over 6.5 million people, which allow us to get a large number of data. Our purposes are (1) making map of night sky brightness all over Japan and (2) providing an opportunity to enjoy gazing star for those who are not usually interested in astronomy.As an interactive function of the app, we put a questionnaire of four choices in which we ask users how many stars are visible in a part of the constellation of Orion. When users answer the question, we get the answer and the position where they are. Depending on the answer, we can roughly recognize the sky brightness of the position.We opened the measurements for several nights. As a result, we could get 4000 - 5000 data all over the country per night. The map of each night is a snapshot of sky brightness of the night including effect of the weather. For example we can recognize that the sky is getting darker as a function of distance from the metropolitan area of Tokyo. We will show the detail results in the presentation.

Sparkling extreme-ultraviolet bright dots observed with Hi-C

International Nuclear Information System (INIS)

Régnier, S.; Alexander, C. E.; Walsh, R. W.; Winebarger, A. R.; Cirtain, J.; Golub, L.; Korreck, K. E.; Weber, M.; Mitchell, N.; Platt, S.; De Pontieu, B.; Title, A.; Kobayashi, K.; Kuzin, S.; DeForest, C. E.

2014-01-01

Observing the Sun at high time and spatial scales is a step toward understanding the finest and fundamental scales of heating events in the solar corona. The high-resolution coronal (Hi-C) instrument has provided the highest spatial and temporal resolution images of the solar corona in the EUV wavelength range to date. Hi-C observed an active region on 2012 July 11 that exhibits several interesting features in the EUV line at 193 Å. One of them is the existence of short, small brightenings 'sparkling' at the edge of the active region; we call these EUV bright dots (EBDs). Individual EBDs have a characteristic duration of 25 s with a characteristic length of 680 km. These brightenings are not fully resolved by the SDO/AIA instrument at the same wavelength; however, they can be identified with respect to the Hi-C location of the EBDs. In addition, EBDs are seen in other chromospheric/coronal channels of SDO/AIA, which suggests a temperature between 0.5 and 1.5 MK. Based on their frequency in the Hi-C time series, we define four different categories of EBDs: single peak, double peak, long duration, and bursty. Based on a potential field extrapolation from an SDO/HMI magnetogram, the EBDs appear at the footpoints of large-scale, trans-equatorial coronal loops. The Hi-C observations provide the first evidence of small-scale EUV heating events at the base of these coronal loops, which have a free magnetic energy of the order of 10 26 erg.

Evolução química de galáxias HII anãs

Science.gov (United States)

Ferraresi, M., Jr.; Cuisinier, F.; Telles, E.

2003-08-01

Galáxias HII anãs são galáxias de baixa massa, com alto conteúdo de gás, e se encontram em uma fase intensa de formação estelar. A taxa de formação estelar está tão alta nestas galáxias que não pode ter se mantido durante sua vida inteira. O tempo máximo de duração do episódio atual de formação estelar deve ser no máximo de algumas dezenas de milhões de anos, bem inferior à idade destas galáxias. Isto leva naturalmente a idéia de que já aconteceram surtos anteriores. Abundâncias químicas oferecem uma ferramenta poderosa para investigar a história evolutiva destas galáxias, porque aumentam de geração em geração estelar. O hidrogênio, o oxigênio, o nitrogênio produzem algumas das linhas mais importantes em um gás foto-ionizado, permitindo a determinação das abundâncias destes elementos facilmente. A dispersão das abundâncias em oxigênio e nitrogênio é significativa, sendo maior que os erros observacionais. O oxigênio é produzido em estrelas massivas, que explodem quase instâneamente, enquanto o nitrogênio é produzido em estrelas de massa intermediária, que só o liberam depois de um atraso de @ 500 mihões de anos. Construímos um modelo de evolução química semi-analítico, utilizando rendimentos empíricos baseados nas abundâncias observadas destes dois elementos. Conseguimos através deste modelo rudimentar explicar nas galáxias de mais baixas metalicidades as abundâncias de oxigênio e de nitrogênio, assim como a dispersão dos dados observacionais devida a formação estelar descontínua, e isto com um número baixo de surtos (1 ou 2, no máximo 3).

Three-Week Bright-Light Intervention Has Dose-Related Effects on Threat-Related Corticolimbic Reactivity and Functional Coupling

DEFF Research Database (Denmark)

Fisher, Patrick M; Madsen, Martin K; Mc Mahon, Brenda

2014-01-01

environmental stimuli (e.g., threat) and may underlie these effects. Serotonin signaling modulates this circuit and is implicated in the pathophysiology of seasonal and other affective disorders. METHODS: We evaluated the effects of a bright-light intervention protocol on threat-related corticolimbic reactivity......-related amygdala and prefrontal reactivity in a dose-dependent manner. Conversely, amygdala-prefrontal and intraprefrontal functional coupling increased significantly in a dose-dependent manner. Genotype status significantly moderated bright-light intervention effects on intraprefrontal functional coupling....... CONCLUSIONS: This is the first study to evaluate the effects of clinically relevant bright-light intervention on threat-related brain function. We show that amygdala-prefrontal reactivity and communication are significantly affected by bright-light intervention, an effect partly moderated by genotype...

Sky brightness and color measurements during the 21 August 2017 total solar eclipse.

Science.gov (United States)

Bruns, Donald G; Bruns, Ronald D

2018-06-01

The sky brightness was measured during the partial phases and during totality of the 21 August 2017 total solar eclipse. A tracking CCD camera with color filters and a wide-angle lens allowed measurements across a wide field of view, recording images every 10 s. The partially and totally eclipsed Sun was kept behind an occulting disk attached to the camera, allowing direct brightness measurements from 1.5° to 38° from the Sun. During the partial phases, the sky brightness as a function of time closely followed the integrated intensity of the unobscured fraction of the solar disk. A redder sky was measured close to the Sun just before totality, caused by the redder color of the exposed solar limb. During totality, a bluer sky was measured, dimmer than the normal sky by a factor of 10,000. Suggestions for enhanced measurements at future eclipses are offered.

Determination atmospheric conditions by evaluating clearness index, turbidity and brightness of the sky

International Nuclear Information System (INIS)

Kandilli, C.

2005-01-01

There are fifteen different sky types which range from totally overcast sky to low turbidity clear sky have been defined by CIE (International Commission on Illumination). For the applications of solar energy engineering and day lighting purposes, it has a great importance to determine the physical characteristics of atmosphere and the sky type. The most important parameters which define the sky type are clearness index, turbidity and brightness. In this study, the parameters of clearness index, turbidity and brightness of the sky belong to Izmir was calculated and their relations with solar radiation and its components were represented according to 10 years data (1994-2004) of meteorology station of Ege University Solar Energy Institute. In this study, clearness index, turbidity, sky clearness and brightness were evaluated to put forward the effects of the these parameters on the atmospheric condition for designing and engineering purposes

Effects of Symbol Brightness Cueing on Attention During a Visual Search of a Cockpit Display of Traffic Information

Science.gov (United States)

Johnson, Walter W.; Liao, Min-Ju; Granada, Stacie

2003-01-01

This study investigated visual search performance for target aircraft symbols on a Cockpit Display of Traffic Information (CDTI). Of primary interest was the influence of target brightness (intensity) and highlighting validity (search directions) on the ability to detect a target aircraft among distractor aircraft. Target aircraft were distinguished by an airspace course that conflicted with Ownship (that is, the participant's aircraft). The display could present all (homogeneous) bright aircraft, all (homogeneous) dim aircraft, or mixed bright and dim aircraft, with the target aircraft being either bright or dim. In the mixed intensity condition, participants may or may not have been instructed whether the target was bright or dim. Results indicated that highlighting validity facilitated better detection times. However, instead of bright targets being detected faster, dim targets were found to be detected more slowly in the mixed intensity display than in the homogeneous display. This relative slowness may be due to a delay in confirming the dim aircraft to be a target when it it was among brighter distractor aircraft. This hypothesis will be tested in future research. Funding for this work was provided by the Advanced Air Transportation Technologies Project of NASA's Airspace Operation Systems Program.

Scale brightness of common goldfish on diet supplemented with seaweed Sargassum sp. and pumpkin Cucurbita moschata

Directory of Open Access Journals (Sweden)

Irfina Manda Astari

2016-02-01

Full Text Available ABSTRACT The common goldfish Carassius auratus auratus is an ornamental freshwater fish species with  high market value. The market value of ornamental fish can be determined through some parameters, one of them is brightness of the fish scales. Brightness level may be enhanced by supplementing plant powder containing carotenoid into fish diet. The purpose of this research was to examine the scale brightness level of common goldfish fed diet supplemented with Sargassum sp. and pumpkin powder, and to determine the dose of those powders that allows higher brightness level of scale.  The feed of common goldfish was supplemented with either Sargassum sp. or pumpkin powder at the doses of 10, 20 and 30%, and without supplementation as control. Fishes were reared for 75 days and fed diet at feeding rate of 5% biomass daily. The results of ANOVA test showed that the Sargassum sp. and pumpkin mill addition on food significantly improved of scales brightness of  common goldfish. Increasing supplementation levels of Sargassum sp. and pumpkin powder increased brightness level of scale. The highest improvement in brightness was the fish that fed by 30% concentration of Sargassum sp. flour with the value scale of brightness was 2.67 and the total number of 2,890.67 chromatophore cells. The results suggest that Sargassum sp. powder is better to improve the brightness level of common goldfish scale. Keywords: Carassius auratus auratus, Sargassum sp., Cucurbita moschata, carotenoid, brightness  ABSTRAK Ikan komet Carassius auratus auratus merupakan salah satu spesies ikan hias air tawar yang memiliki nilai jual tinggi. Nilai jual ikan hias dapat ditentukan melalui beberapa parameter, salah satunya yaitu kecerahan sisik ikan. Kecerahan sisik ikan dapat ditingkatkan melalui pemberian pakan yang diperkaya karotenoid. Tujuan penelitian ini adalah menguji tingkat kecerahan warna sisik ikan komet setelah diberi pakan dengan tambahan tepung Sargassum sp. dan

Brightness enhancement of a multi-mode ribbon fiber using transmitting Bragg gratings

Science.gov (United States)

Anderson, B. M.; Venus, G.; Ott, D.; Divliansky, I.; Dawson, J. W.; Drachenberg, D. R.; Messerly, M. J.; Pax, P. H.; Tassano, J. B.; Glebov, L. B.

2015-03-01

Increasing the dimensions of a waveguide provides the simplest means of reducing detrimental nonlinear effects, but such systems are inherently multi-mode, reducing the brightness of the system. Furthermore, using rectangular dimensions allows for improved heat extraction, as well as uniform temperature profile within the core. We propose a method of using the angular acceptance of a transmitting Bragg grating (TBG) to filter the fundamental mode of a fiber laser resonator, and as a means to increase the brightness of multi-mode fiber laser. Numerical modeling is used to calculate the diffraction losses needed to suppress the higher order modes in a laser system with saturable gain. The model is tested by constructing an external cavity resonator using an ytterbium doped ribbon fiber with core dimensions of 107.8μm by 8.3μm as the active medium. We show that the TBG increases the beam quality of the system from M2 = 11.3 to M2 = 1.45, while reducing the slope efficiency from 76% to 53%, overall increasing the brightness by 5.1 times.

A study of the H I and optical properties of Low Surface Brightness galaxies: spirals, dwarfs, and irregulars

Science.gov (United States)

Honey, M.; van Driel, W.; Das, M.; Martin, J.-M.

2018-06-01

We present a study of the H I and optical properties of nearby (z ≤ 0.1) Low Surface Brightness galaxies (LSBGs). We started with a literature sample of ˜900 LSBGs and divided them into three morphological classes: spirals, irregulars, and dwarfs. Of these, we could use ˜490 LSBGs to study their H I and stellar masses, colours, and colour-magnitude diagrams, and local environment, compare them with normal, High Surface Brightness (HSB) galaxies and determine the differences between the three morphological classes. We found that LSB and HSB galaxies span a similar range in H I and stellar masses, and have a similar M_{H I}/M⋆-M⋆ relationship. Among the LSBGs, as expected, the spirals have the highest average H I and stellar masses, both of about 109.8 M⊙. The LSGBs' (g - r) integrated colour is nearly constant as function of H I mass for all classes. In the colour-magnitude diagram, the spirals are spread over the red and blue regions whereas the irregulars and dwarfs are confined to the blue region. The spirals also exhibit a steeper slope in the M_{H I}/M⋆-M⋆ plane. Within their local environment, we confirmed that LSBGs are more isolated than HSB galaxies, and LSB spirals more isolated than irregulars and dwarfs. Kolmogorov-Smirnov statistical tests on the H I mass, stellar mass, and number of neighbours indicate that the spirals are a statistically different population from the dwarfs and irregulars. This suggests that the spirals may have different formation and H I evolution than the dwarfs and irregulars.

Far infrared spectroscopy of H II regions

International Nuclear Information System (INIS)

Ward, D.B.

1976-01-01

A fully liquid helium cooled grating spectrometer has been developed for far infrared observations from the NASA Lear Jet. This instrument has been used in observations of the galactic HII regions M42 and M17. The instrument is described, and the results of various performance tests and calibrations are presented. The methods employed in observations from the Lear Jet are described, and the data analysis procedures are discussed. The results of a search for the (O III) 88.16 micron fine structure line are presented. The intensity of the line in M17 is reported, and an upper limit given for the intensity in M42. These results are compared with theoretical predictions, and future applications of infrared line observations are discussed. Coarse resolution spectra of M42 and M17 from 45 to 115 microns are also presented. The emission from M42 is shown to be a very smooth function of wavelength, closely fitting the wavelength dependence of a 105 0 K graybody. The spectrum of M17 is very different, having a bump at approximately 75 microns and a general far infrared excess. The observed spectrum is compared to the predictions of models for M17

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

2016-01-27

Jan 27, 2016 ... We report multi-frequency radio continuum and hydrogen radio recombination line observations of HII regions near = 24.8°, = 0.1° using the Giant Metrewave Radio Telescope(GMRT) at 1.28 GHz ( = 172), 0.61 GHz ( = 220) and the Very Large Array (VLA) at 1.42 GHz ( = 166). The region consists ...

The "Brightness Rules" Alternative Conception for Light Bulb Circuits

Science.gov (United States)

Bryan, Joel A.; Stuessy, Carol

2006-01-01

An alternative conception for the observed differences in light bulb brightness was revealed during an unguided inquiry investigation in which prospective elementary teachers placed identical bulbs in series, parallel, and combination direct current circuits. Classroom observations, document analyses, and video and audio transcriptions led to the…

Effect of Different Tree canopies on the Brightness Temperature of Snowpack

Science.gov (United States)

Mousavi, S.; De Roo, R. D.; Brucker, L.

2017-12-01

Snow stores the water we drink and is essential to grow food that we eat. But changes in snow quantities such as snow water equivalent (SWE) are underway and have serious consequences. So, effective management of the freshwater reservoir requires to monitor frequently (weekly or better) the spatial distribution of SWE and snowpack wetness. Both microwave radar and radiometer systems have long been considered as relevant remote sensing tools in retrieving globally snow physical parameters of interest thanks to their all-weather operation capability. However, their observations are sensitive to the presence of tree canopies, which in turns impacts SWE estimation. To address this long-lasting challenge, we parked a truck-mounted microwave radiometer system for an entire winter in a rare area where it exists different tree types in the different cardinal directions. We used dual-polarization microwave radiometers at three different frequencies (1.4, 19, and 37 GHz), mounted on a boom truck to observe continuously the snowpack surrounding the truck. Observations were recorded at different incidence angles. These measurements have been collected in Grand Mesa National Forest, Colorado as part of the NASA SnowEx 2016-17. In this presentation, the effect of Engelmann Spruce and Aspen trees on the measured brightness temperature of snow is discussed. It is shown that Engelmann Spruce trees increases the brightness temperature of the snowpack more than Aspen trees do. Moreover, the elevation angular dependence of the measured brightness temperatures of snowpack with and without tree canopies is investigated in the context of SWE retrievals. A time-lapse camera was monitoring a snow post installed in the sensors' field of view to characterize the brightness temperature change as snow depth evolved. Also, our study takes advantage of the snowpit measurements that were collected near the radiometers' field of view.

Performance of the Hack's Impairment Index Score: A Novel Tool to Assess Impairment from Alcohol in Emergency Department Patients.

Science.gov (United States)

Hack, Jason B; Goldlust, Eric J; Ferrante, Dennis; Zink, Brian J

2017-10-01

Over 35 million alcohol-impaired (AI) patients are cared for in emergency departments (EDs) annually. Emergency physicians are charged with ensuring AI patients' safety by identifying resolution of alcohol-induced impairment. The most common standard evaluation is an extemporized clinical examination, as ethanol levels are not reliable or predictive of clinical symptoms. There is no standard assessment of ED AI patients. The objective was to evaluate a novel standardized ED assessment of alcohol impairment, Hack's Impairment Index (HII score), in a busy urban ED. A retrospective chart review was performed for all AI patients seen in our busy urban ED over 24 months. Trained nurses evaluated AI patients with both "usual" and HII score every 2 hours. Patients were stratified by frequency of visits for AI during this time: high (≥ 6), medium (2-5), and low (1). Within each category, comparisons were made between HII scores, measured ethanol levels, and usual nursing assessment of AI. Changes in HII scores over time were also evaluated. A total of 8,074 visits from 3,219 unique patients were eligible for study, including 7,973 (98.7%) with ethanol levels, 5,061 (62.7%) with complete HII scores, and 3,646 (45.2%) with health care provider assessments. Correlations between HII scores and ethanol levels were poor (Pearson's R 2  = 0.09, 0.09, and 0.17 for high-, medium-, and low-frequency strata). HII scores were excellent at discriminating nursing assessment of AI, while ethanol levels were less effective. Omitting extrema, HII scores fell consistently an average 0.062 points per hour, throughout patients' visits. The HII score applied a quantitative, objective assessment of alcohol impairment. HII scores were superior to ethanol levels as an objective clinical measure of impairment. The HII declines in a reasonably predictable manner over time, with serial evaluations corresponding well with health care provider evaluations. © 2017 by the Society for Academic