WorldWideScience

Sample records for luminous cluster underlying

  1. Luminous arcs in clusters of galaxies

    International Nuclear Information System (INIS)

    Lynds, R.; Petrosian, V.

    1989-01-01

    Observations are reported of what appears to be a new class of spatially coherent extragalactic features having, in the two most compelling known examples, the following joint properties: location in clusters of galaxies, narrow arclike shape, enormous apparent length, and situation of center of curvature toward both a cD galaxy and the apparent center of gravity of the cluster. The principal available facts concerning the arcs are presented and a variety of interpretations are briefly discussed. The weight of evidence seems to favor the interpretation that these features are images of more distant objects produced by the gravitational field of the intervening clusters. 24 references

  2. Clustering of very luminous infrared galaxies and their environment

    Science.gov (United States)

    Gao, YU

    1993-01-01

    The IRAS survey reveals a class of ultraluminous infrared (IR) galaxies (ULIRG's) with IR luminosities comparable to the bolometric luminosities of quasars. The nature, origin, and evolution of ULIRG's are attracting more and more attention recently. Since galaxy morphology is certainly a function of environment, morphological observations show that ULIRG's are interacting/merging galaxies, and some ULIRG's might be the dust-enshrouded quasars (S88) or giant ellipticals, the study of ULIRG's environment and large scale clustering effects should be worthwhile. ULIRG's and very luminous IR galaxies have been selected from the 2Jy IRAS redshift survey. Meanwhile, a catalog of IRAS groups of galaxies has been constructed using a percolation-like algorithm. Therefore, whether ULIRG's and/or VLIRG's have a group environment can be checked immediately. Other aspects of the survey are discussed.

  3. Night sky luminance under clear sky conditions: Theory vs. experiment

    International Nuclear Information System (INIS)

    Kocifaj, Miroslav

    2014-01-01

    Sky glow is caused by both natural phenomena and factors of anthropogenic origin, and of the latter ground-based light sources are the most important contributors for they emit the spatially linked spectral radiant intensity distribution of artificial light sources, which are further modulated by local atmospheric optics and perceived as the diffuse light of a night sky. In other words, sky glow is closely related to a city's shape and pattern of luminaire distribution, in practical effect an almost arbitrary deployment of random orientation of heterogeneous electrical light sources. Thus the luminance gradation function measured in a suburban zone or near the edges of a city is linked to the City Pattern or vice versa. It is shown that clear sky luminance/radiance data recorded in an urban area can be used to retrieve the bulk luminous/radiant intensity distribution if some a-priori information on atmospheric aerosols is available. For instance, the single scattering albedo of aerosol particles is required under low turbidity conditions, as demonstrated on a targeted experiment in the city of Frýdek-Mistek. One of the main advantages of the retrieval method presented in this paper is that the single scattering approximation is satisfactorily accurate in characterizing the light field near the ground because the dominant contribution to the sky glow has originated from beams propagated along short optical paths. - Highlights: • Urban sky glow is interpreted in terms of city emission function. • Luminance function in a suburban zone is linked to the City Pattern. • Single scattering approximation is applicable in modeling urban sky glow. • Information on aerosols represents valuable inputs to the retrieval procedure. • Sky glow patterns vary with light source distribution and spectral emission

  4. Clustering Batik Images using Fuzzy C-Means Algorithm Based on Log-Average Luminance

    Directory of Open Access Journals (Sweden)

    Ahmad Sanmorino

    2012-06-01

    Full Text Available Batik is a fabric or clothes that are made ​​with a special staining technique called wax-resist dyeing and is one of the cultural heritage which has high artistic value. In order to improve the efficiency and give better semantic to the image, some researchers apply clustering algorithm for managing images before they can be retrieved. Image clustering is a process of grouping images based on their similarity. In this paper we attempt to provide an alternative method of grouping batik image using fuzzy c-means (FCM algorithm based on log-average luminance of the batik. FCM clustering algorithm is an algorithm that works using fuzzy models that allow all data from all cluster members are formed with different degrees of membership between 0 and 1. Log-average luminance (LAL is the average value of the lighting in an image. We can compare different image lighting from one image to another using LAL. From the experiments that have been made, it can be concluded that fuzzy c-means algorithm can be used for batik image clustering based on log-average luminance of each image possessed.

  5. A Massive, Cooling-Flow-Induced Starburst in the Core of a Highly Luminous Galaxy Cluster

    Science.gov (United States)

    McDonald, M.; Bayliss, M.; Benson, B. A.; Foley, R. J.; Ruel, J.; Sullivan, P.; Veilleux, S.; Aird, K. A.; Ashby, M. L. N.; Bautz, M.; hide

    2012-01-01

    In the cores of some galaxy clusters the hot intracluster plasma is dense enough that it should cool radiatively in the cluster s lifetime, leading to continuous "cooling flows" of gas sinking towards the cluster center, yet no such cooling flow has been observed. The low observed star formation rates and cool gas masses for these "cool core" clusters suggest that much of the cooling must be offset by astrophysical feedback to prevent the formation of a runaway cooling flow. Here we report X-ray, optical, and infrared observations of the galaxy cluster SPT-CLJ2344-4243 at z = 0.596. These observations reveal an exceptionally luminous (L(sub 2-10 keV) = 8.2 10(exp 45) erg/s) galaxy cluster which hosts an extremely strong cooling flow (M(sub cool) = 3820 +/- 530 Stellar Mass/yr). Further, the central galaxy in this cluster appears to be experiencing a massive starburst (740 +/- 160 Stellar Mass/ yr), which suggests that the feedback source responsible for preventing runaway cooling in nearby cool core clusters may not yet be fully established in SPT-CLJ2344-4243. This large star formation rate implies that a significant fraction of the stars in the central galaxy of this cluster may form via accretion of the intracluster medium, rather than the current picture of central galaxies assembling entirely via mergers.

  6. What drives the evolution of Luminous Compact Blue Galaxies in Clusters vs. the Field?

    Science.gov (United States)

    Wirth, Gregory D.; Bershady, Matthew A.; Crawford, Steven M.; Hunt, Lucas; Pisano, Daniel J.; Randriamampandry, Solohery M.

    2018-06-01

    Low-mass dwarf ellipticals are the most numerous members of present-day galaxy clusters, but the progenitors of this dominant population remain unclear. A prime candidate is the class of objects known as Luminous Compact Blue Galaxies (LCBGs), common in intermediate-redshift clusters but virtually extinct today. Recent cosmological simulations suggest that present-day dwarf galaxies begin as irregular field galaxies, undergo an environmentally-driven starburst phase as they enter the cluster, and stop forming stars earlier than their counterparts in the field. This model predicts that cluster dwarfs should have lower stellar mass per unit dynamical mass than their counterparts in the field. We are undertaking a two-pronged archival research program to test this key prediction using the combination of precision photometry from space and high-quality spectroscopy. First, we are combining optical HST/ACS imaging of five z=0.55 clusters (including two HST Frontier Fields) with Spitzer IR imaging and publicly-released Keck/DEIMOS spectroscopy to measure stellar-to-dynamical-mass ratios for a large sample of cluster LCBGs. Second, we are exploiting a new catalog of LCBGs in the COSMOS field to gather corresponding data for a significant sample of field LCBGs. By comparing mass ratios from these datasets, we aim to test theoretical predictions and determine the primary physical driver of cluster dwarf-galaxy evolution.

  7. Underlying mechanisms of transient luminous events: a review

    OpenAIRE

    V. V. Surkov; M. Hayakawa

    2012-01-01

    Transient luminous events (TLEs) occasionally observed above a strong thunderstorm system have been the subject of a great deal of research during recent years. The main goal of this review is to introduce readers to recent theories of electrodynamics processes associated with TLEs. We examine the simplest versions of these theories in order to make their physics as transparent as possible. The study is begun with the conventional mechanism for air breakdown at stratospheric...

  8. Underlying mechanisms of transient luminous events: a review

    Directory of Open Access Journals (Sweden)

    V. V. Surkov

    2012-08-01

    Full Text Available Transient luminous events (TLEs occasionally observed above a strong thunderstorm system have been the subject of a great deal of research during recent years. The main goal of this review is to introduce readers to recent theories of electrodynamics processes associated with TLEs. We examine the simplest versions of these theories in order to make their physics as transparent as possible. The study is begun with the conventional mechanism for air breakdown at stratospheric and mesospheric altitudes. An electron impact ionization and dissociative attachment to neutrals are discussed. A streamer size and mobility of electrons as a function of altitude in the atmosphere are estimated on the basis of similarity law. An alternative mechanism of air breakdown, runaway electron mechanism, is discussed. In this section we focus on a runaway breakdown field, characteristic length to increase avalanche of runaway electrons and on the role played by fast seed electrons in generation of the runaway breakdown. An effect of thunderclouds charge distribution on initiation of blue jets and gigantic jets is examined. A model in which the blue jet is treated as upward-propagating positive leader with a streamer zone/corona on the top is discussed. Sprite models based on streamer-like mechanism of air breakdown in the presence of atmospheric conductivity are reviewed. To analyze conditions for sprite generation, thunderstorm electric field arising just after positive cloud-to-ground stroke is compared with the thresholds for propagation of positively/negatively charged streamers and with runway breakdown. Our own estimate of tendril's length at the bottom of sprite is obtained to demonstrate that the runaway breakdown can trigger the streamer formation. In conclusion we discuss physical mechanisms of VLF (very low frequency and ELF (extremely low frequency phenomena associated with sprites.

  9. Integrative clustering reveals a novel split in the luminal A subtype of breast cancer with impact on outcome

    DEFF Research Database (Denmark)

    Aure, Miriam Ragle; Vitelli, Valeria; Jernström, Sandra

    2017-01-01

    subtypes revealed six major groups. Five corresponded well with the mRNA subtypes, while a sixth group resulted from a split of the luminal A subtype; these tumors belonged to distinct microRNA clusters. Gain-of-function studies using MCF-7 cells showed that microRNAs differentially expressed between...

  10. Constraints on cold dark matter theories from observations of massive x-ray-luminous clusters of galaxies at high redshift

    Science.gov (United States)

    Luppino, G. A.; Gioia, I. M.

    1995-01-01

    During the course of a gravitational lensing survey of distant, X-ray selected Einstein Observatory Extended Medium Sensitivity Survey (EMSS) clusters of galaxies, we have studied six X-ray-luminous (L(sub x) greater than 5 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) clusters at redshifts exceeding z = 0.5. All of these clusters are apparently massive. In addition to their high X-ray luminosity, two of the clusters at z approximately 0.6 exhibit gravitationally lensed arcs. Furthermore, the highest redshift cluster in our sample, MS 1054-0321 at z = 0.826, is both extremely X-ray luminous (L(sub 0.3-3.5keV)=9.3 x 10(exp 44)(h(sub 50)(exp -2))ergs/sec) and exceedingly rich with an optical richness comparable to an Abell Richness Class 4 cluster. In this Letter, we discuss the cosmological implications of the very existence of these clusters for hierarchical structure formation theories such as standard Omega = 1 CDM (cold dark matter), hybrid Omega = 1 C + HDM (hot dark matter), and flat, low-density Lambda + CDM models.

  11. Influence of Al{sub 2}O{sub 3} reflective layer under phosphor layer on luminance and luminous efficiency characteristics in alternating-current plasma display panel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Choon-Sang [School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu (Korea, Republic of); Tae, Heung-Sik, E-mail: hstae@ee.knu.ac.kr [School of Electronics Engineering, College of IT Engineering, Kyungpook National University, Daegu (Korea, Republic of); Jung, Eun Young [Core Technology Lab., Corporate R and D Center, Samsung SDI Company Ltd., Cheonan (Korea, Republic of)

    2013-11-29

    This paper examines the optical and discharge characteristics of alternating-current plasma display panel when adopting the Al{sub 2}O{sub 3} reflective layer. The Al{sub 2}O{sub 3} reflective layer is deposited under the phosphor layer by using the screen-printing method. The resulting changes in the optical and discharge characteristics, including the power consumption, color temperature, luminance, luminous efficiency, scanning electron microscopy image, and reflectance, are then compared for both cases with and without Al{sub 2}O{sub 3} reflective layer. As a result of optimizing the thicknesses between the Al{sub 2}O{sub 3} and phosphor layers, the luminance and luminous efficiency are improved by about 17% and 7%, respectively. - Highlights: • We examine characteristics of plasma display panel when adopting reflective layer. • Al{sub 2}O{sub 3} reflective layer was deposited under the phosphor layer. • Al{sub 2}O{sub 3} reflective layer with flaky shape is very effective in enhancing luminance.

  12. CLUSTERING OF SLOAN DIGITAL SKY SURVEY III PHOTOMETRIC LUMINOUS GALAXIES: THE MEASUREMENT, SYSTEMATICS, AND COSMOLOGICAL IMPLICATIONS

    International Nuclear Information System (INIS)

    Ho, Shirley; White, Martin; Schlegel, David J.; Seljak, Uros; Reid, Beth; Cuesta, Antonio; Padmanabhan, Nikhil; Seo, Hee-Jong; De Putter, Roland; Ross, Ashley J.; Percival, Will J.; Saito, Shun; Schlafly, Eddie; Hernández-Monteagudo, Carlos; Sánchez, Ariel G.; Blanton, Michael; Skibba, Ramin; Schneider, Don; Mena, Olga; Viel, Matteo

    2012-01-01

    The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg 2 , and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg 2 and probes a volume of 3 h –3 Gpc 3 , making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of ∼15%, with a bin size of δ l = 10 on scales of the baryon acoustic oscillations (BAOs; at l ∼ 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat ΛCDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H 0 constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find Ω Λ = 0.73 ± 0.019 and H 0 to be 70.5 ± 1.6 s –1 Mpc –1 km. For an open ΛCDM model, when combined with WMAP7 + HST, we find Ω K = 0.0035 ± 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = –1.071 ± 0.078, and H 0 to be 71.3 ± 1.7 s –1 Mpc –1 km, which is competitive with the latest large-scale structure constraints from large spectroscopic surveys such as the SDSS Data Release 7 (DR7) and WiggleZ. We also find that systematic-corrected power

  13. CLUSTERING OF SLOAN DIGITAL SKY SURVEY III PHOTOMETRIC LUMINOUS GALAXIES: THE MEASUREMENT, SYSTEMATICS, AND COSMOLOGICAL IMPLICATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Ho, Shirley; White, Martin; Schlegel, David J.; Seljak, Uros; Reid, Beth [Lawrence Berkeley National Laboratory, 1 Cyclotron Rd, MS 50R-5045, Berkeley, CA 94720 (United States); Cuesta, Antonio; Padmanabhan, Nikhil [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Seo, Hee-Jong [Berkeley Center for Cosmological Physics, LBL and Department of Physics, University of California, Berkeley, CA 94720 (United States); De Putter, Roland [ICC, University of Barcelona (IEEC-UB), Marti i Franques 1, E-08028 Barcelona (Spain); Ross, Ashley J.; Percival, Will J. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Saito, Shun [Department of Astronomy, University of California Berkeley, CA (United States); Schlafly, Eddie [Department of Astronomy, Harvard University, 60 Garden St. MS 20, Cambridge, MA 02138 (United States); Hernandez-Monteagudo, Carlos [Centro de Estudios de Fisica del Cosmos de Aragon (CEFCA), Plaza de San Juan 1, planta 2, E-44001 Teruel (Spain); Sanchez, Ariel G. [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching (Germany); Blanton, Michael [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Skibba, Ramin [Steward Observatory, University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721 (United States); Schneider, Don [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Mena, Olga [Instituto de Fisica Corpuscular, Universidad de Valencia-CSIC (Spain); Viel, Matteo, E-mail: cwho@lbl.gov [INAF-Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, I-34131 Trieste (Italy); and others

    2012-12-10

    The Sloan Digital Sky Survey (SDSS) surveyed 14,555 deg{sup 2}, and delivered over a trillion pixels of imaging data. We present a study of galaxy clustering using 900,000 luminous galaxies with photometric redshifts, spanning between z = 0.45 and z = 0.65, constructed from the SDSS using methods described in Ross et al. This data set spans 11,000 deg{sup 2} and probes a volume of 3 h {sup -3} Gpc{sup 3}, making it the largest volume ever used for galaxy clustering measurements. We describe in detail the construction of the survey window function and various systematics affecting our measurement. With such a large volume, high-precision cosmological constraints can be obtained given careful control and understanding of the observational systematics. We present a novel treatment of the observational systematics and its applications to the clustering signals from the data set. In this paper, we measure the angular clustering using an optimal quadratic estimator at four redshift slices with an accuracy of {approx}15%, with a bin size of {delta}{sub l} = 10 on scales of the baryon acoustic oscillations (BAOs; at l {approx} 40-400). We also apply corrections to the power spectra due to systematics and derive cosmological constraints using the full shape of the power spectra. For a flat {Lambda}CDM model, when combined with cosmic microwave background Wilkinson Microwave Anisotropy Probe 7 (WMAP7) and H{sub 0} constraints from using 600 Cepheids observed by Wide Field Camera 3 (WFC3; HST), we find {Omega}{sub {Lambda}} = 0.73 {+-} 0.019 and H{sub 0} to be 70.5 {+-} 1.6 s{sup -1} Mpc{sup -1} km. For an open {Lambda}CDM model, when combined with WMAP7 + HST, we find {Omega}{sub K} = 0.0035 {+-} 0.0054, improved over WMAP7+HST alone by 40%. For a wCDM model, when combined with WMAP7+HST+SN, we find w = -1.071 {+-} 0.078, and H{sub 0} to be 71.3 {+-} 1.7 s{sup -1} Mpc{sup -1} km, which is competitive with the latest large-scale structure constraints from large spectroscopic

  14. Hot spots effect on infrared spectral luminance emitted by carbon under plasma particles impact

    International Nuclear Information System (INIS)

    Delchambre, E.; Reichle, R.; Mitteau, R.; Missirlian, M.; Gobin, R.

    2004-01-01

    During the last Tore Supra campaigns, an anomalous deformation in the near infrared spectrum of radiation has been observed on neutralizer underneath the Toroidal Pumped Limiter (TPL) on which we observed the growth of carbon layer. The consequence is the difficulty to asses the surface temperature of the components and the power loaded. Laboratory experiment has been performed, using an Electron Cyclotron Resonance (ECR) ions source, to reproduce, characterize and explain this phenomenon. The luminance emitted by Carbon Fibre Composite (CFC) and pyrolytic graphite, have been observed under 95 keV of H+ bombardments. The amplitude of the deformation was found to depend on the type of material used and the power density of the incident power loaded. This paper presents the possible hot spots explanation. The experimental luminance deformation is reproduced and these results are validated using a thermal model of dust in radiate equilibrium. (authors)

  15. The Atacama Cosmology Telescope: Detection or Sunyaev-Zel'Dovich Decrement in Groups and Clusters Associated with Luminous Red Galaxies

    Science.gov (United States)

    Hand, Nick; Appel, John William; Battaglia, Nick; Bond, J. Richard; Das, Sudeep; Devlin, Mark J.; Dunkley, Joanna; Dunner, Rolando; Essinger-Hileman, Thomas; Fowler, Joseph W.; hide

    2010-01-01

    We present a detection of the Sunyaev-Zel'dovich (SZ) decrement associated with the Luminous Red Galaxy (LRG) sample of the Sloan Digital Sky Survey. The SZ data come from 148 GHz maps of the equatorial region made by the Atacama Cosmology Telescope (ACT). The LRG sample is divided by luminosity into four bins, and estimates for the central Sunyaev-Zel'dovich temperature decrement are calculated through a stacking process. We detect and account for a bias of the SZ signal due to weak radio sources. We use numerical simulations to relate the observed decrement to Y(sub 200) and clustering properties to relate the galaxy luminosity bins to mass. We also use a relation between BCG luminosity and cluster mass based on stacked gravitational lensing measurements to estimate the characteristic halo masses. The masses are found to be in the range approx.10(exp 13) - 10(exp 14)/h Stellar Mass, a lower range than has been previously probed.

  16. The x-ray luminous galaxy cluster population at 0.9 < z ≲ 1.6 as revealed by the XMM-Newton Distant Cluster Project

    International Nuclear Information System (INIS)

    Fassbender, R; Böhringer, H; Nastasi, A; Šuhada, R; Mühlegger, M; Mohr, J J; Pierini, D; De Hoon, A; Kohnert, J; Lamer, G; Schwope, A D; Pratt, G W; Quintana, H; Rosati, P; Santos, J S

    2011-01-01

    We present the largest sample to date of spectroscopically confirmed x-ray luminous high-redshift galaxy clusters comprising 22 systems in the range 0.9 2 of non-contiguous deep archival XMM-Newton coverage, of which 49.4 deg 2 are part of the core survey with a quantifiable selection function and 17.7 deg 2 are classified as ‘gold’ coverage as the starting point for upcoming cosmological applications. Distant cluster candidates were followed up with moderately deep optical and near-infrared imaging in at least two bands to photometrically identify the cluster galaxy populations and obtain redshift estimates based on the colors of simple stellar population models. We test and calibrate the most promising redshift estimation techniques based on the R-z and z-H colors for efficient distant cluster identifications and find a good redshift accuracy performance of the z-H color out to at least z ∼ 1.5, while the redshift evolution of the R-z color leads to increasingly large uncertainties at z ≳ 0.9. Photometrically identified high-z systems are spectroscopically confirmed with VLT/FORS 2 with a minimum of three concordant cluster member redshifts. We present first details of two newly identified clusters, XDCP J0338.5+0029 at z = 0.916 and XDCP J0027.2+1714 at z = 0.959, and investigate the x-ray properties of SpARCS J003550-431224 at z = 1.335, which shows evidence for ongoing major merger activity along the line-of-sight. We provide x-ray properties and luminosity-based total mass estimates for the full sample of 22 high-z clusters, of which 17 are at z ⩾ 1.0 and seven populate the highest redshift bin at z > 1.3. The median system mass of the sample is M 200 ≃ 2 × 10 14 M ⊙ , while the probed mass range for the distant clusters spans approximately (0.7-7) × 10 14 M ⊙ . The majority (>70%) of the x-ray selected clusters show rather regular x-ray morphologies, albeit in most cases with a discernible elongation along one axis. In contrast to

  17. Spectroscopy of Luminous Compact Blue Galaxies in Distant Clusters. I. Spectroscopic Data

    Science.gov (United States)

    Crawford, Steven M.; Wirth, Gregory D.; Bershady, Matthew A.; Hon, Kimo

    2011-11-01

    We used the DEIMOS spectrograph on the Keck II Telescope to obtain spectra of galaxies in the fields of five distant, rich galaxy clusters over the redshift range 0.5 reported in the literature, except for 11 targets which we believe were previously in error. Within our sample, we confirm the presence of 53 LCBGs in the five galaxy clusters. The clusters all stand out as distinct peaks in the redshift distribution of LCBGs with the average number density of LCBGs ranging from 1.65 ± 0.25 Mpc-3 at z = 0.55 to 3.13 ± 0.65 Mpc-3 at z = 0.8. The number density of LCBGs in clusters exceeds the field density by a factor of 749 ± 116 at z = 0.55; at z = 0.8, the corresponding ratio is E = 416 ± 95. At z = 0.55, this enhancement is well above that seen for blue galaxies or the overall cluster population, indicating that LCBGs are preferentially triggered in high-density environments at intermediate redshifts. Based in part on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.

  18. Constraints on Modified Gravity from the Abundance of X-ray Luminous Galaxy Clusters

    DEFF Research Database (Denmark)

    Rapetti Serra, David Angelo

    2011-01-01

    n December 2010, the XXL survey, an XMM-Newton Very Large Programme, has been granted time to map two extragalactic regions of 25 deg2, at a depth of ~5×10-15 erg/cm2/s (using 10 ks observations). While the main goal of the project is to constrain the Dark Energy equation of state using clusters...... of galaxies (cf. http://arxiv.org/abs/1009.3182), it will also have lasting legacy value for cluster scaling laws and studies of AGNs and XRB. The project is open to any scientist belonging to the international astronomical community, and interested in actively contributing to the general legacy effort...

  19. NEAR-INFRARED ADAPTIVE OPTICS IMAGING OF INFRARED LUMINOUS GALAXIES: THE BRIGHTEST CLUSTER MAGNITUDE-STAR FORMATION RATE RELATION

    International Nuclear Information System (INIS)

    Randriamanakoto, Z.; Väisänen, P.; Escala, A.; Kankare, E.; Kotilainen, J.; Mattila, S.; Ryder, S.

    2013-01-01

    We have established a relation between the brightest super star cluster (SSC) magnitude in a galaxy and the host star formation rate (SFR) for the first time in the near-infrared (NIR). The data come from a statistical sample of ∼40 luminous IR galaxies (LIRGs) and starbursts utilizing K-band adaptive optics imaging. While expanding the observed relation to longer wavelengths, less affected by extinction effects, it also pushes to higher SFRs. The relation we find, M K ∼ –2.6log SFR, is similar to that derived previously in the optical and at lower SFRs. It does not, however, fit the optical relation with a single optical to NIR color conversion, suggesting systematic extinction and/or age effects. While the relation is broadly consistent with a size-of-sample explanation, we argue physical reasons for the relation are likely as well. In particular, the scatter in the relation is smaller than expected from pure random sampling strongly suggesting physical constraints. We also derive a quantifiable relation tying together cluster-internal effects and host SFR properties to possibly explain the observed brightest SSC magnitude versus SFR dependency

  20. Fermi Detection of a Luminous gamma-ray Pulsar in a Globular Cluster

    Science.gov (United States)

    Freire, P. C. C.; Abdo, A. A.; Ajello, M.; Allafort, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Blandford, R. D.; hide

    2011-01-01

    We report the Fermi Large Area Telescope detection of gamma -ray (>100 mega-electron volts) pulsations from pulsar J1823--3021A in the globular cluster NGC 6624 with high significance (approx 7 sigma). Its gamma-ray luminosity L (sub 3) = (8:4 +/- 1:6) X 10(exp 34) ergs per second, is the highest observed for any millisecond pulsar (MSP) to date, and it accounts for most of the cluster emission. The non-detection of the cluster in the off-pulse phase implies that its contains < 32 gamma-ray MSPs, not approx 100 as previously estimated. The gamma -ray luminosity indicates that the unusually large rate of change of its period is caused by its intrinsic spin-down. This implies that J1823--3021A has the largest magnetic field and is the youngest MSP ever detected, and that such anomalous objects might be forming at rates comparable to those of the more normal MSPs.

  1. Fermi detection of a luminous γ-ray pulsar in a globular cluster.

    Science.gov (United States)

    2011-11-25

    We report on the Fermi Large Area Telescope's detection of γ-ray (>100 mega-electron volts) pulsations from pulsar J1823-3021A in the globular cluster NGC 6624 with high significance (~7 σ). Its γ-ray luminosity, L(γ) = (8.4 ± 1.6) × 10(34) ergs per second, is the highest observed for any millisecond pulsar (MSP) to date, and it accounts for most of the cluster emission. The nondetection of the cluster in the off-pulse phase implies that it contains <32 γ-ray MSPs, not ~100 as previously estimated. The γ-ray luminosity indicates that the unusually large rate of change of its period is caused by its intrinsic spin-down. This implies that J1823-3021A has the largest magnetic field and is the youngest MSP ever detected and that such anomalous objects might be forming at rates comparable to those of the more normal MSPs.

  2. Test of Gravity on Large Scales with Weak Gravitational Lensing and Clustering Measurements of SDSS Luminous Red Galaxies

    Science.gov (United States)

    Reyes, Reinabelle; Mandelbaum, R.; Seljak, U.; Gunn, J.; Lombriser, L.

    2009-01-01

    We perform a test of gravity on large scales (5-50 Mpc/h) using 70,000 luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) DR7 with redshifts 0.16clustering-- that can discriminate between different theories of gravity and is largely independent of galaxy bias and sigma_8. In particular, E_G is sensitive to the relation between the spatial and temporal scalar perturbations in the space-time metric. While these two potentials are equivalent in concordance cosmology (GR+LCDM) in the absence of anisotropic stress, they are not equivalent in alternative theories of gravity in general, so that different models make different predictions for E_G. We find E_G=0.37±0.05 averaged over scales 5

  3. A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster

    Science.gov (United States)

    Lin, Dacheng; Strader, Jay; Carrasco, Eleazar R.; Page, Dany; Romanowsky, Aaron J.; Homan, Jeroen; Irwin, Jimmy A.; Remillard, Ronald A.; Godet, Olivier; Webb, Natalie A.; Baumgardt, Holger; Wijnands, Rudy; Barret, Didier; Duc, Pierre-Alain; Brodie, Jean P.; Gwyn, Stephen D. J.

    2018-06-01

    A unique signature for the presence of massive black holes in very dense stellar regions is occasional giant-amplitude outbursts of multi-wavelength radiation from tidal disruption and subsequent accretion of stars that make a close approach to the black holes1. Previous strong tidal disruption event (TDE) candidates were all associated with the centres of largely isolated galaxies2-6. Here, we report the discovery of a luminous X-ray outburst from a massive star cluster at a projected distance of 12.5 kpc from the centre of a large lenticular galaxy. The luminosity peaked at 1043 erg s-1 and decayed systematically over 10 years, approximately following a trend that supports the identification of the event as a TDE. The X-ray spectra were all very soft, with emission confined to be ≲3.0 keV, and could be described with a standard thermal disk. The disk cooled significantly as the luminosity decreased—a key thermal-state signature often observed in accreting stellar-mass black holes. This thermal-state signature, coupled with very high luminosities, ultrasoft X-ray spectra and the characteristic power-law evolution of the light curve, provides strong evidence that the source contains an intermediate-mass black hole with a mass tens of thousand times that of the solar mass. This event demonstrates that one of the most effective means of detecting intermediate-mass black holes is through X-ray flares from TDEs in star clusters.

  4. Nature versus nurture: Luminous blue variable nebulae in and near massive stellar clusters at the galactic center

    International Nuclear Information System (INIS)

    Lau, R. M.; Herter, T. L.; Adams, J. D.; Morris, M. R.

    2014-01-01

    Three luminous blue variables (LBVs) are located in and near the Quintuplet Cluster at the Galactic center: the Pistol Star, G0.120-0.048, and qF362. We present imaging at 19, 25, 31, and 37 μm of the region containing these three LBVs, obtained with SOFIA using FORCAST. We argue that Pistol and G0.120-0.048 are identical 'twins' that exhibit contrasting nebulae due to the external influence of their different environments. Our images reveal the asymmetric, compressed shell of hot dust surrounding the Pistol Star and provide the first detection of the thermal emission from the symmetric, hot dust envelope surrounding G0.120-0.048. However, no detection of hot dust associated with qF362 is made. Dust and gas composing the Pistol nebula are primarily heated and ionized by the nearby Quintuplet Cluster stars. The northern region of the Pistol nebula is decelerated due to the interaction with the high-velocity (2000 km s –1 ) winds from adjacent Wolf-Rayet Carbon (WC) stars. From fits to the spectral energy distribution (SED) of the Pistol nebula with the DustEM code we determine that the Pistol nebula is composed of a distribution of very small, transiently heated grains (10 to ∼ 35 Å) having a total dust mass of 0.03 M ☉ , and that it exhibits a gradient of decreasing grain size from south to north due to differential sputtering by the winds from the WC stars. The total IR luminosity of the Pistol nebula is 5.2 × 10 5 L ☉ . Dust in the G0.120-0.048 nebula is primarily heated by the central star; however, the nebular gas is ionized externally by the Arches Cluster. Unlike the Pistol nebula, the G0.120-0.048 nebula is freely expanding into the surrounding medium. A grain size distribution identical to that of the non-sputtered region of the Pistol nebula satisfies the constraints placed on the G0.120-0.048 nebula from DustEM model fits to its SED and implies a total dust mass of 0.021 M ☉ . The total IR luminosity of the G0.120-0.048 nebula is

  5. Nature versus nurture: Luminous blue variable nebulae in and near massive stellar clusters at the galactic center

    Energy Technology Data Exchange (ETDEWEB)

    Lau, R. M.; Herter, T. L.; Adams, J. D. [Astronomy Department, 202 Space Sciences Building, Cornell University, Ithaca, NY 14853-6801 (United States); Morris, M. R. [Department of Physics and Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90095-1547 (United States)

    2014-04-20

    Three luminous blue variables (LBVs) are located in and near the Quintuplet Cluster at the Galactic center: the Pistol Star, G0.120-0.048, and qF362. We present imaging at 19, 25, 31, and 37 μm of the region containing these three LBVs, obtained with SOFIA using FORCAST. We argue that Pistol and G0.120-0.048 are identical 'twins' that exhibit contrasting nebulae due to the external influence of their different environments. Our images reveal the asymmetric, compressed shell of hot dust surrounding the Pistol Star and provide the first detection of the thermal emission from the symmetric, hot dust envelope surrounding G0.120-0.048. However, no detection of hot dust associated with qF362 is made. Dust and gas composing the Pistol nebula are primarily heated and ionized by the nearby Quintuplet Cluster stars. The northern region of the Pistol nebula is decelerated due to the interaction with the high-velocity (2000 km s{sup –1}) winds from adjacent Wolf-Rayet Carbon (WC) stars. From fits to the spectral energy distribution (SED) of the Pistol nebula with the DustEM code we determine that the Pistol nebula is composed of a distribution of very small, transiently heated grains (10 to ∼ 35 Å) having a total dust mass of 0.03 M {sub ☉}, and that it exhibits a gradient of decreasing grain size from south to north due to differential sputtering by the winds from the WC stars. The total IR luminosity of the Pistol nebula is 5.2 × 10{sup 5} L {sub ☉}. Dust in the G0.120-0.048 nebula is primarily heated by the central star; however, the nebular gas is ionized externally by the Arches Cluster. Unlike the Pistol nebula, the G0.120-0.048 nebula is freely expanding into the surrounding medium. A grain size distribution identical to that of the non-sputtered region of the Pistol nebula satisfies the constraints placed on the G0.120-0.048 nebula from DustEM model fits to its SED and implies a total dust mass of 0.021 M {sub ☉}. The total IR luminosity of the G

  6. Cluster-cluster aggregation of Ising dipolar particles under thermal noise

    KAUST Repository

    Suzuki, Masaru; Kun, Ferenc; Ito, Nobuyasu

    2009-01-01

    The cluster-cluster aggregation processes of Ising dipolar particles under thermal noise are investigated in the dilute condition. As the temperature increases, changes in the typical structures of clusters are observed from chainlike (D1

  7. A CFH12k lensing survey of X-ray luminous galaxy clusters - II. Weak lensing analysis and global correlations

    NARCIS (Netherlands)

    Bardeau, S.; Soucail, G.; Kneib, J.-P.; Czoske, O.; Ebeling, H.; Hudelot, P.; Smail, I.; Smith, G. P.

    Aims. We present a wide-field multi-color survey of a homogeneous sample of eleven clusters of galaxies for which we measure total masses and mass distributions from weak lensing. This sample, spanning a small range in both X-ray luminosity and redshift, is ideally suited to determining the

  8. A YOUNG ECLIPSING BINARY AND ITS LUMINOUS NEIGHBORS IN THE EMBEDDED STAR CLUSTER Sh 2-252E

    Energy Technology Data Exchange (ETDEWEB)

    Lester, Kathryn V.; Gies, Douglas R.; Guo, Zhao, E-mail: lester@chara.gsu.edu, E-mail: gies@chara.gsu.edu, E-mail: guo@chara.gsu.edu [Center for High Angular Resolution Astronomy and Department of Physics and Astronomy, Georgia State University, P.O. Box 5060, Atlanta, GA 30302-5060 (United States)

    2016-12-01

    We present a photometric and light curve analysis of an eccentric eclipsing binary in the K2 Campaign 0 field, which resides in Sh 2-252E, a young star cluster embedded in an H ii region. We describe a spectroscopic investigation of the three brightest stars in the crowded aperture to identify which is the binary system. We find that none of these stars are components of the eclipsing binary system, which must be one of the fainter nearby stars. These bright cluster members all have remarkable spectra: Sh 2-252a (EPIC 202062176) is a B0.5 V star with razor sharp absorption lines, Sh 2-252b is a Herbig A0 star with disk-like emission lines, and Sh 2-252c is a pre-main-sequence star with very red color.

  9. THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. III. IMPLICATIONS FOR GALAXY CLUSTERS AND THE FORMATION OF DWARF GALAXIES

    International Nuclear Information System (INIS)

    Pfrommer, Christoph; Chang, Philip; Broderick, Avery E.

    2012-01-01

    A subset of blazars are powerful TeV emitters, dominating the extragalactic component of the very high energy gamma-ray universe (E ∼> 100 GeV). These TeV gamma rays generate ultrarelativistic electron-positron pairs via pair production with the extragalactic background light. While it has generally been assumed that the kinetic energy of these pairs cascades to GeV gamma rays via inverse Compton scattering, we have argued in Broderick et al. (Paper I in this series) that plasma beam instabilities are capable of dissipating the pairs' energy locally on timescales short in comparison to the inverse Compton cooling time, heating the intergalactic medium (IGM) with a rate that is independent of density. This dramatically increases the entropy of the IGM after redshift z ∼ 2, with a number of important implications for structure formation: (1) this suggests a scenario for the origin of the cool core (CC)/non-cool core (NCC) bimodality in galaxy clusters and groups. Early-forming galaxy groups are unaffected because they can efficiently radiate the additional entropy, developing a CC. However, late-forming groups do not have sufficient time to cool before the entropy is gravitationally reprocessed through successive mergers—counteracting cooling and potentially raising the core entropy further. This may result in a population of X-ray dim groups/clusters, consistent with X-ray stacking analyses of optically selected samples. Hence, blazar heating works differently than feedback by active galactic nuclei, which we show can balance radiative cooling but is unable to transform CC into NCC clusters on the buoyancy timescale due to the weak coupling between the mechanical energy to the cluster gas. (2) We predict a suppression of the Sunyaev-Zel'dovich (SZ) power spectrum template on angular scales smaller than 5' due to the globally reduced central pressure of groups and clusters forming after z ∼ 1. This allows for a larger rms amplitude of the density power

  10. Cluster-cluster aggregation of Ising dipolar particles under thermal noise

    KAUST Repository

    Suzuki, Masaru

    2009-08-14

    The cluster-cluster aggregation processes of Ising dipolar particles under thermal noise are investigated in the dilute condition. As the temperature increases, changes in the typical structures of clusters are observed from chainlike (D1) to crystalline (D2) through fractal structures (D1.45), where D is the fractal dimension. By calculating the bending energy of the chainlike structure, it is found that the transition temperature is associated with the energy gap between the chainlike and crystalline configurations. The aggregation dynamics changes from being dominated by attraction to diffusion involving changes in the dynamic exponent z=0.2 to 0.5. In the region of temperature where the fractal clusters grow, different growth rates are observed between charged and neutral clusters. Using the Smoluchowski equation with a twofold kernel, this hetero-aggregation process is found to result from two types of dynamics: the diffusive motion of neutral clusters and the weak attractive motion between charged clusters. The fact that changes in structures and dynamics take place at the same time suggests that transitions in the structure of clusters involve marked changes in the dynamics of the aggregation processes. © 2009 The American Physical Society.

  11. The evolution of and starburst-agn connection in luminous and ultraluminous infrared galaxies and their link to globular cluster formation

    Science.gov (United States)

    Fiorenza, Stephanie Lynn

    The evolutionary connection between nuclear starbursts and active galactic nuclei (AGN) in luminous infrared galaxies (LIRGs; 1011 diagrams. I show that for the U/LIRGs in my sample the properties that describe their nuclear starbursts and AGN (e.g. star formation rate (SFR), L[O III], optical D parameter, D4000, and EW(Hdelta)) are independent of one another, ensuring that no biases affect correlations between these properties and objects' locations on the BPT diagrams. I then derive evolutionary paths on the BPT diagram involving [N II]/Halpha that are based on how these properties vary between two U/LIRGs positioned at the end-points. The paths involve U/LIRGs that decrease in SFR and increase in AGN activity. Paths with U/LIRGs that evolve into high luminosity AGN likely do so due to recent, strong starbursts. Second, to study how the properties of the IR power sources in U/LIRGs vary, I use a combination of photometric data points that I carefully measure (using photometry from SDSS, 2MASS, WISE, and Spitzer) and that I retrieve from catalogues (IRAS, AKARI, and ISO) to perform UV to FIR SED-fitting with CIGALE (Code Investigating GALaxy Emission) for 34 U/LIRGs from the IRAS 2 Jy Redshift Survey with 0.01 statistical analysis, and fit an exponential curve to the data to describe the expected amount of decrease in SFR seen for a U/LIRG in my sample over a given change in starburst age. Finally, I find evidence that the stellar mass and starburst mass fractions influence whether a U/LIRG in my sample will have a strong AGN and SFR, respectively. I compare the SFR-Mstar relationship seen in my sample with those predicted by models and found from previous observations. I find that the U/LIRGs with older starbursts (>125 Myr) agree with previous results, while those with younger starbursts show a large dispersion in Mstar. I conclude that this is supporting evidence that the star formation histories and timescales at which the IR power sources in U/LIRGs evolve

  12. Luminance requirements for lighted signage

    Science.gov (United States)

    Freyssinier, Jean Paul; Narendran, Nadarajah; Bullough, John D.

    2006-08-01

    Light-emitting diode (LED) technology is presently targeted to displace traditional light sources in backlighted signage. The literature shows that brightness and contrast are perhaps the two most important elements of a sign that determine its attention-getting capabilities and its legibility. Presently, there are no luminance standards for signage, and the practice of developing brighter signs to compete with signs in adjacent businesses is becoming more commonplace. Sign luminances in such cases may far exceed what people usually need for identifying and reading a sign. Furthermore, the practice of higher sign luminance than needed has many negative consequences, including higher energy use and light pollution. To move toward development of a recommendation for lighted signage, several laboratory human factors evaluations were conducted. A scale model of a storefront was used to present human subjects with a typical red channel-letter sign at luminances ranging from 8 cd/m2 to 1512 cd/m2 under four background luminances typical of nighttime outdoor and daytime inside-mall conditions (1, 100, 300, 1000 cd/m2), from three scaled viewing distances (30, 60, 340 ft), and either in isolation or adjacent to two similar signs. Subjects rated the brightness, acceptability, and ease of reading of the test sign for each combination of sign and background luminances and scaled viewing distances.

  13. Reliability Evaluation for Clustered WSNs under Malware Propagation

    Directory of Open Access Journals (Sweden)

    Shigen Shen

    2016-06-01

    Full Text Available We consider a clustered wireless sensor network (WSN under epidemic-malware propagation conditions and solve the problem of how to evaluate its reliability so as to ensure efficient, continuous, and dependable transmission of sensed data from sensor nodes to the sink. Facing the contradiction between malware intention and continuous-time Markov chain (CTMC randomness, we introduce a strategic game that can predict malware infection in order to model a successful infection as a CTMC state transition. Next, we devise a novel measure to compute the Mean Time to Failure (MTTF of a sensor node, which represents the reliability of a sensor node continuously performing tasks such as sensing, transmitting, and fusing data. Since clustered WSNs can be regarded as parallel-serial-parallel systems, the reliability of a clustered WSN can be evaluated via classical reliability theory. Numerical results show the influence of parameters such as the true positive rate and the false positive rate on a sensor node’s MTTF. Furthermore, we validate the method of reliability evaluation for a clustered WSN according to the number of sensor nodes in a cluster, the number of clusters in a route, and the number of routes in the WSN.

  14. Reliability Evaluation for Clustered WSNs under Malware Propagation.

    Science.gov (United States)

    Shen, Shigen; Huang, Longjun; Liu, Jianhua; Champion, Adam C; Yu, Shui; Cao, Qiying

    2016-06-10

    We consider a clustered wireless sensor network (WSN) under epidemic-malware propagation conditions and solve the problem of how to evaluate its reliability so as to ensure efficient, continuous, and dependable transmission of sensed data from sensor nodes to the sink. Facing the contradiction between malware intention and continuous-time Markov chain (CTMC) randomness, we introduce a strategic game that can predict malware infection in order to model a successful infection as a CTMC state transition. Next, we devise a novel measure to compute the Mean Time to Failure (MTTF) of a sensor node, which represents the reliability of a sensor node continuously performing tasks such as sensing, transmitting, and fusing data. Since clustered WSNs can be regarded as parallel-serial-parallel systems, the reliability of a clustered WSN can be evaluated via classical reliability theory. Numerical results show the influence of parameters such as the true positive rate and the false positive rate on a sensor node's MTTF. Furthermore, we validate the method of reliability evaluation for a clustered WSN according to the number of sensor nodes in a cluster, the number of clusters in a route, and the number of routes in the WSN.

  15. Reliability Evaluation for Clustered WSNs under Malware Propagation

    Science.gov (United States)

    Shen, Shigen; Huang, Longjun; Liu, Jianhua; Champion, Adam C.; Yu, Shui; Cao, Qiying

    2016-01-01

    We consider a clustered wireless sensor network (WSN) under epidemic-malware propagation conditions and solve the problem of how to evaluate its reliability so as to ensure efficient, continuous, and dependable transmission of sensed data from sensor nodes to the sink. Facing the contradiction between malware intention and continuous-time Markov chain (CTMC) randomness, we introduce a strategic game that can predict malware infection in order to model a successful infection as a CTMC state transition. Next, we devise a novel measure to compute the Mean Time to Failure (MTTF) of a sensor node, which represents the reliability of a sensor node continuously performing tasks such as sensing, transmitting, and fusing data. Since clustered WSNs can be regarded as parallel-serial-parallel systems, the reliability of a clustered WSN can be evaluated via classical reliability theory. Numerical results show the influence of parameters such as the true positive rate and the false positive rate on a sensor node’s MTTF. Furthermore, we validate the method of reliability evaluation for a clustered WSN according to the number of sensor nodes in a cluster, the number of clusters in a route, and the number of routes in the WSN. PMID:27294934

  16. XMM-Newton X-ray and HST weak gravitational lensing study of the extremely X-ray luminous galaxy cluster Cl J120958.9+495352 (z = 0.902)

    Science.gov (United States)

    Thölken, Sophia; Schrabback, Tim; Reiprich, Thomas H.; Lovisari, Lorenzo; Allen, Steven W.; Hoekstra, Henk; Applegate, Douglas; Buddendiek, Axel; Hicks, Amalia

    2018-03-01

    Context. Observations of relaxed, massive, and distant clusters can provide important tests of standard cosmological models, for example by using the gas mass fraction. To perform this test, the dynamical state of the cluster and its gas properties have to be investigated. X-ray analyses provide one of the best opportunities to access this information and to determine important properties such as temperature profiles, gas mass, and the total X-ray hydrostatic mass. For the last of these, weak gravitational lensing analyses are complementary independent probes that are essential in order to test whether X-ray masses could be biased. Aims: We study the very luminous, high redshift (z = 0.902) galaxy cluster Cl J120958.9+495352 using XMM-Newton data. We measure global cluster properties and study the temperature profile and the cooling time to investigate the dynamical status with respect to the presence of a cool core. We use Hubble Space Telescope (HST) weak lensing data to estimate its total mass and determine the gas mass fraction. Methods: We perform a spectral analysis using an XMM-Newton observation of 15 ks cleaned exposure time. As the treatment of the background is crucial, we use two different approaches to account for the background emission to verify our results. We account for point spread function effects and deproject our results to estimate the gas mass fraction of the cluster. We measure weak lensing galaxy shapes from mosaic HST imaging and select background galaxies photometrically in combination with imaging data from the William Herschel Telescope. Results: The X-ray luminosity of Cl J120958.9+495352 in the 0.1-2.4 keV band estimated from our XMM-Newton data is LX = (13.4+1.2-1.0) × 1044 erg/s and thus it is one of the most X-ray luminous clusters known at similarly high redshift. We find clear indications for the presence of a cool core from the temperature profile and the central cooling time, which is very rare at such high redshifts. Based

  17. Bulgarian clusters under development: Political framework and results

    Directory of Open Access Journals (Sweden)

    Bankova Yovka

    2011-01-01

    Full Text Available The idea of clusters is not new but nowadays clusters are in a highlight again. Through cluster policies the countries aim at raising their national competitiveness. The paper deals with two objectives - discussion and evaluation of the strategic framework for clusters in Bulgaria and an analysis of the state of Bulgarian clusters. The paper presents briefly general issues concerning the national competitiveness and clusters as being one of the possible instruments to achieve a sustainable competitiveness. The practice of the policy in the EU in the field of clusters is the basis for conclusions about the role of the governments. The second part deals with the strategic framework for the cluster initiatives in Bulgaria and with a selection of indicators about the SMEs and clusters in the country. On this basis a conclusion about the development stage of Bulgarian clusters is derived.

  18. Investigation of Color Constancy in 4.5-Month-Old Infants under a Strict Control of Luminance Contrast for Individual Participants

    Science.gov (United States)

    Yang, Jiale; Kanazawa, So; Yamaguchi, Masami K.; Kuriki, Ichiro

    2013-01-01

    The current study examined color constancy in infants using a familiarization paradigm. We first obtained isoluminance in each infant as defined by the minimum motion paradigm and used these data to control the luminance of stimuli in the main experiments. In the familiarization phase of the main experiment, two identical smiling face patterns…

  19. Fine interstitial clusters as recombinators in decomposing solid solutions under irradiation

    International Nuclear Information System (INIS)

    Trushin, Yu.V.

    1991-01-01

    Behaviour of interstitial clusters and their roll in processes of radiation swelling of metals are described. It is shown that occurrence of coherent advanced precipitations during decomposition of solid solutions under irradiation leads to matrix supersaturation over interstitial atoms. This enhances recombination of unlike defects due to vacancy precipitation on fine interstitial clusters. Evaluation of cluster sizes was conducted

  20. The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: cosmic flows and cosmic web from luminous red galaxies

    Science.gov (United States)

    Ata, Metin; Kitaura, Francisco-Shu; Chuang, Chia-Hsun; Rodríguez-Torres, Sergio; Angulo, Raul E.; Ferraro, Simone; Gil-Marín, Hector; McDonald, Patrick; Hernández Monteagudo, Carlos; Müller, Volker; Yepes, Gustavo; Autefage, Mathieu; Baumgarten, Falk; Beutler, Florian; Brownstein, Joel R.; Burden, Angela; Eisenstein, Daniel J.; Guo, Hong; Ho, Shirley; McBride, Cameron; Neyrinck, Mark; Olmstead, Matthew D.; Padmanabhan, Nikhil; Percival, Will J.; Prada, Francisco; Rossi, Graziano; Sánchez, Ariel G.; Schlegel, David; Schneider, Donald P.; Seo, Hee-Jong; Streblyanska, Alina; Tinker, Jeremy; Tojeiro, Rita; Vargas-Magana, Mariana

    2017-06-01

    We present a Bayesian phase-space reconstruction of the cosmic large-scale matter density and velocity fields from the Sloan Digital Sky Survey-III Baryon Oscillations Spectroscopic Survey Data Release 12 CMASS galaxy clustering catalogue. We rely on a given Λ cold dark matter cosmology, a mesh resolution in the range of 6-10 h-1 Mpc, and a lognormal-Poisson model with a redshift-dependent non-linear bias. The bias parameters are derived from the data and a general renormalized perturbation theory approach. We use combined Gibbs and Hamiltonian sampling, implemented in the argo code, to iteratively reconstruct the dark matter density field and the coherent peculiar velocities of individual galaxies, correcting hereby for coherent redshift space distortions. Our tests relying on accurate N-body-based mock galaxy catalogues show unbiased real space power spectra of the non-linear density field up to k ˜ 0.2 h Mpc-1, and vanishing quadrupoles down to r ˜ 20 h-1 Mpc. We also demonstrate that the non-linear cosmic web can be obtained from the tidal field tensor based on the Gaussian component of the reconstructed density field. We find that the reconstructed velocities have a statistical correlation coefficient compared to the true velocities of each individual light-cone mock galaxy of r ˜ 0.68 including about 10 per cent of satellite galaxies with virial motions (about r = 0.75 without satellites). The power spectra of the velocity divergence agree well with theoretical predictions up to k ˜ 0.2 h Mpc-1. This work will be especially useful to improve, for example, baryon acoustic oscillation reconstructions, kinematic Sunyaev-Zeldovich, integrated Sachs-Wolfe measurements or environmental studies.

  1. Farmer Performance under Competitive Pressure in Agro-cluster Regions

    NARCIS (Netherlands)

    Wardhana, D.; Ihle, R.; Heijman, W.J.M.

    2017-01-01

    Agro-clusters would allow farmers to acquire positive and negative externalities. On one hand, smallholder farmers in spatial proximity are likely to benefit from this concentration; on the other hand, they incur high competitive pressure from other neighboring farmers. We examine the link between

  2. Missing continuous outcomes under covariate dependent missingness in cluster randomised trials.

    Science.gov (United States)

    Hossain, Anower; Diaz-Ordaz, Karla; Bartlett, Jonathan W

    2017-06-01

    Attrition is a common occurrence in cluster randomised trials which leads to missing outcome data. Two approaches for analysing such trials are cluster-level analysis and individual-level analysis. This paper compares the performance of unadjusted cluster-level analysis, baseline covariate adjusted cluster-level analysis and linear mixed model analysis, under baseline covariate dependent missingness in continuous outcomes, in terms of bias, average estimated standard error and coverage probability. The methods of complete records analysis and multiple imputation are used to handle the missing outcome data. We considered four scenarios, with the missingness mechanism and baseline covariate effect on outcome either the same or different between intervention groups. We show that both unadjusted cluster-level analysis and baseline covariate adjusted cluster-level analysis give unbiased estimates of the intervention effect only if both intervention groups have the same missingness mechanisms and there is no interaction between baseline covariate and intervention group. Linear mixed model and multiple imputation give unbiased estimates under all four considered scenarios, provided that an interaction of intervention and baseline covariate is included in the model when appropriate. Cluster mean imputation has been proposed as a valid approach for handling missing outcomes in cluster randomised trials. We show that cluster mean imputation only gives unbiased estimates when missingness mechanism is the same between the intervention groups and there is no interaction between baseline covariate and intervention group. Multiple imputation shows overcoverage for small number of clusters in each intervention group.

  3. The self limiting effect of hydrogen cluster in gas jet under liquid nitrogen temperature

    International Nuclear Information System (INIS)

    Han Jifeng; Yang Chaowen; Miao Jingwei; Fu Pengtao; Luo Xiaobing; Shi Miangong

    2010-01-01

    The generation of hydrogen clusters in gas jet is tested using the Rayleigh scattering method under liquid nitrogen temperature of 79 K. The self limiting effect of hydrogen cluster is studied and it is found that the cluster formation is greatly affected by the number of expanded molecules. The well designed liquid nitrogen cold trap ensured that the hydrogen cluster would keep maximum size for maximum 15 ms during one gas jet. The scattered light intensity exhibits a power scaling on the backing pressure ranging from 5 to 48 bar with the power value of 4.1.

  4. Paul Callaghan luminous moments

    CERN Document Server

    Callaghan, Paul

    2013-01-01

    Acknowledged internationally for his ground-breaking scientific research in the field of magnetic resonance, Sir Paul Callaghan was a scientist and visionary with a rare gift for promoting science to a wide audience. He was named New Zealander of the Year in 2011. His death in early 2012 robbed New Zealand of an inspirational leader. Paul Callaghan: Luminous Moments brings together some of his most significant writing. Whether he describes his childhood in Wanganui, reflects on discovering the beauty of science, sets out New Zealand's future potential or discusses the experience of fa

  5. The VIMOS Public Extragalactic Redshift Survey (VIPERS). An unbiased estimate of the growth rate of structure at ⟨z⟩ = 0.85 using the clustering of luminous blue galaxies

    Science.gov (United States)

    Mohammad, F. G.; Granett, B. R.; Guzzo, L.; Bel, J.; Branchini, E.; de la Torre, S.; Moscardini, L.; Peacock, J. A.; Bolzonella, M.; Garilli, B.; Scodeggio, M.; Abbas, U.; Adami, C.; Bottini, D.; Cappi, A.; Cucciati, O.; Davidzon, I.; Franzetti, P.; Fritz, A.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; Polletta, M.; Pollo, A.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Arnouts, S.; Coupon, J.; De Lucia, G.; Ilbert, O.; Moutard, T.

    2018-02-01

    We used the VIMOS Public Extragalactic Redshift Survey (VIPERS) final data release (PDR-2) to investigate the performance of colour-selected populations of galaxies as tracers of linear large-scale motions. We empirically selected volume-limited samples of blue and red galaxies as to minimise the systematic error on the estimate of the growth rate of structure fσ8 from the anisotropy of the two-point correlation function. To this end, rather than rigidly splitting the sample into two colour classes we defined the red or blue fractional contribution of each object through a weight based on the (U - V ) colour distribution. Using mock surveys that are designed to reproduce the observed properties of VIPERS galaxies, we find the systematic error in recovering the fiducial value of fσ8 to be minimised when using a volume-limited sample of luminous blue galaxies. We modelled non-linear corrections via the Scoccimarro extension of the Kaiser model (with updated fitting formulae for the velocity power spectra), finding systematic errors on fσ8 of below 1-2%, using scales as small as 5 h-1 Mpc. We interpret this result as indicating that selection of luminous blue galaxies maximises the fraction that are central objects in their dark matter haloes; this in turn minimises the contribution to the measured ξ(rp,π) from the 1-halo term, which is dominated by non-linear motions. The gain is inferior if one uses the full magnitude-limited sample of blue objects, consistent with the presence of a significant fraction of blue, fainter satellites dominated by non-streaming, orbital velocities. We measured a value of fσ8 = 0.45 ± 0.11 over the single redshift range 0.6 ≤ z ≤ 1.0, corresponding to an effective redshift for the blue galaxies ⟨z⟩=0.85. Including in the likelihood the potential extra information contained in the blue-red galaxy cross-correlation function does not lead to an appreciable improvement in the error bars, while it increases the systematic error

  6. clusters

    Indian Academy of Sciences (India)

    2017-09-27

    Sep 27, 2017 ... Author for correspondence (zh4403701@126.com). MS received 15 ... lic clusters using density functional theory (DFT)-GGA of the DMOL3 package. ... In the process of geometric optimization, con- vergence thresholds ..... and Postgraduate Research & Practice Innovation Program of. Jiangsu Province ...

  7. clusters

    Indian Academy of Sciences (India)

    environmental as well as technical problems during fuel gas utilization. ... adsorption on some alloys of Pd, namely PdAu, PdAg ... ried out on small neutral and charged Au24,26,27, Cu,28 ... study of Zanti et al.29 on Pdn (n = 1–9) clusters.

  8. Effect of impurities on the growth of {113} interstitial clusters in silicon under electron irradiation

    Science.gov (United States)

    Nakai, K.; Hamada, K.; Satoh, Y.; Yoshiie, T.

    2011-01-01

    The growth and shrinkage of interstitial clusters on {113} planes were investigated in electron irradiated Czochralski grown silicon (Cz-Si), floating-zone silicon (Fz-Si), and impurity-doped Fz-Si (HT-Fz-Si) using a high voltage electron microscope. In Fz-Si, {113} interstitial clusters were formed only near the beam incident surface after a long incubation period, and shrank on subsequent irradiation from the backside of the specimen. In Cz-Si and HT-Fz-Si, {113} interstitial clusters nucleated uniformly throughout the specimen without incubation, and began to shrink under prolonged irradiation at higher electron beam intensity. At lower beam intensity, however, the {113} interstitial cluster grew stably. These results demonstrate that the {113} interstitial cluster cannot grow without a continuous supply of impurities during electron irradiation. Detailed kinetics of {113} interstitial cluster growth and shrinkage in silicon, including the effects of impurities, are proposed. Then, experimental results are analyzed using rate equations based on these kinetics.

  9. Luminous bacteria cultured from fish guts in the Gulf of Oman.

    Science.gov (United States)

    Makemson, J C; Hermosa, G V

    1999-01-01

    The incidence of culturable luminous bacteria in Omani market fish guts was correlated to habitat type amongst 109 species of fish. Isolated representative luminous bacteria were compared to known species using the Biolog system (95 traits/isolate) and cluster analysis, which showed that the main taxa present in fish guts were clades related to Vibrio harveyi and Photobacterium species with sporadic incidence of P. phosphoreum. The luminous isolates from gut of the slip-mouth (barred pony fish), Leiognathus fasciatus, were mainly a type related to Photobacterium but phenotypically different from known species. These luminous gut bacteria were identical with the bacteria in the light organ, indicating that the light organ supplies a significant quantity of luminous bacteria to the gut. In many of the fish that lack light organs, luminous bacteria were also the dominant bacterial type in the gut, while in some others luminous bacteria were encountered sporadically and at low densities, reflecting the incidence of culturable luminous bacteria in seawater. Pelagic fish contained the highest incidence of culturable luminous bacteria and reef-associated fish the lowest. No correlation was found between the incidence of culturable luminous bacteria and the degree to which fish produce a melanin-covered gut. Copyright 1999 John Wiley & Sons, Ltd.

  10. Push-and-stick mechanism for charged and excited small cluster emission under ion bombardment

    International Nuclear Information System (INIS)

    Bitensky, I.S.; Parilis, E.S.; Wojciechowski, I.A.

    1992-01-01

    The mechanism for the formation, excitation and ionization of small clusters emitted under ion bombardment is discussed. It is shown that the increased degree of ionization for the transition metal dimers, trimers and tetramers can be explained by the existence of an additional effective channel for their formation, namely the associative ionization process. A simple estimate shows that the sticking together of a fast cascade atom and the pushed out surface atom is 30-40 times more effective for dimer formation, than the recombination of two fast atoms. This push-and-stick mechanism of cluster formation could also be effective for the formation of trimers and tetramers. (orig.)

  11. Formation mechanism of solute clusters under neutron irradiation in ferritic model alloys and in a reactor pressure vessel steel: clusters of defects

    International Nuclear Information System (INIS)

    Meslin-Chiffon, E.

    2007-11-01

    The embrittlement of reactor pressure vessel (RPV) under irradiation is partly due to the formation of point defects (PD) and solute clusters. The aim of this work was to gain more insight into the formation mechanisms of solute clusters in low copper ([Cu] = 0.1 wt%) FeCu and FeCuMnNi model alloys, in a copper free FeMnNi model alloy and in a low copper French RPV steel (16MND5). These materials were neutron-irradiated around 300 C in a test reactor. Solute clusters were characterized by tomographic atom probe whereas PD clusters were simulated with a rate theory numerical code calibrated under cascade damage conditions using transmission electron microscopy analysis. The confrontation between experiments and simulation reveals that a heterogeneous irradiation-induced solute precipitation/segregation probably occurs on PD clusters. (author)

  12. Ion induced electron emission statistics under Agm- cluster bombardment of Ag

    Science.gov (United States)

    Breuers, A.; Penning, R.; Wucher, A.

    2018-05-01

    The electron emission from a polycrystalline silver surface under bombardment with Agm- cluster ions (m = 1, 2, 3) is investigated in terms of ion induced kinetic excitation. The electron yield γ is determined directly by a current measurement method on the one hand and implicitly by the analysis of the electron emission statistics on the other hand. Successful measurements of the electron emission spectra ensure a deeper understanding of the ion induced kinetic electron emission process, with particular emphasis on the effect of the projectile cluster size to the yield as well as to emission statistics. The results allow a quantitative comparison to computer simulations performed for silver atoms and clusters impinging onto a silver surface.

  13. Crouch gait patterns defined using k-means cluster analysis are related to underlying clinical pathology.

    Science.gov (United States)

    Rozumalski, Adam; Schwartz, Michael H

    2009-08-01

    In this study a gait classification method was developed and applied to subjects with Cerebral palsy who walk with excessive knee flexion at initial contact. Sagittal plane gait data, simplified using the gait features method, is used as input into a k-means cluster analysis to determine homogeneous groups. Several clinical domains were explored to determine if the clusters are related to underlying pathology. These domains included age, joint range-of-motion, strength, selective motor control, and spasticity. Principal component analysis is used to determine one overall score for each of the multi-joint domains (strength, selective motor control, and spasticity). The current study shows that there are five clusters among children with excessive knee flexion at initial contact. These clusters were labeled, in order of increasing gait pathology: (1) mild crouch with mild equinus, (2) moderate crouch, (3) moderate crouch with anterior pelvic tilt, (4) moderate crouch with equinus, and (5) severe crouch. Further analysis showed that age, range-of-motion, strength, selective motor control, and spasticity were significantly different between the clusters (p<0.001). The general tendency was for the clinical domains to worsen as gait pathology increased. This new classification tool can be used to define homogeneous groups of subjects in crouch gait, which can help guide treatment decisions and outcomes assessment.

  14. Massive Star Clusters in Ongoing Galaxy Interactions: Clues to Cluster Formation

    Science.gov (United States)

    Keel, William C.; Borne, Kirk D.

    2003-09-01

    We present HST WFPC2 observations, supplemented by ground-based Hα data, of the star-cluster populations in two pairs of interacting galaxies selected for being in very different kinds of encounters seen at different stages. Dynamical information and n-body simulations provide the details of encounter geometry, mass ratio, and timing. In NGC 5752/4 we are seeing a weak encounter, well past closest approach, after about 2.5×108 yr. The large spiral NGC 5754 has a normal population of disk clusters, while the fainter companion NGC 5752 exhibits a rich population of luminous clusters with a flatter luminosity function. The strong, ongoing encounter in NGC 6621/2, seen about 1.0×108 yr past closest approach between roughly equal-mass galaxies, has produced an extensive population of luminous clusters, particularly young and luminous in a small region between the two nuclei. This region is dynamically interesting, with such a strong perturbation in the velocity field that the rotation curve reverses sign. From these results, in comparison with other strongly interacting systems discussed in the literature, cluster formation requires a threshold level of perturbation, with stage of the interaction a less important factor. The location of the most active star formation in NGC 6621/2 draws attention to a possible role for the Toomre stability threshold in shaping star formation in interacting galaxies. The rich cluster populations in NGC 5752 and NGC 6621 show that direct contact between gas-rich galaxy disks is not a requirement to form luminous clusters and that they can be triggered by processes happening within a single galaxy disk (albeit triggered by external perturbations). Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  15. Effects of absolute luminance and luminance contrast on visual search in low mesopic environments.

    Science.gov (United States)

    Hunter, Mathew; Godde, Ben; Olk, Bettina

    2018-03-26

    Diverse adaptive visual processing mechanisms allow us to complete visual search tasks in a wide visual photopic range (>0.6 cd/m 2 ). Whether search strategies or mechanisms known from this range extend below, in the mesopic and scotopic luminance spectra (search in more complex-feature and conjunction-search paradigms. The results verify the previously reported deficiency windows defined by an interaction of base luminance and luminance contrast for more complex visual-search tasks. Based on significant regression analyses, a more precise definition of the magnitude of contribution of different contrast parameters. Characterized feature search patterns had approximately a 2.5:1 ratio of contribution from the Michelson contrast property relative to Weber contrast, whereas the ratio was approximately 1:1 in a serial-search condition. The results implicate near-complete magnocellular isolation in a visual-search paradigm that has yet to be demonstrated. Our analyses provide a new method of characterizing visual search and the first insight in its underlying mechanisms in luminance environments in the low mesopic and scotopic spectra.

  16. Life prediction of OLED for constant-stress accelerated degradation tests using luminance decaying model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jianping, E-mail: jpzhanglzu@163.com [College of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Li, Wenbin [College of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Cheng, Guoliang; Chen, Xiao [Shanghai Tianyi Electric Co., Ltd., Shanghai 201611 (China); Wu, Helen [School of Computing, Engineering and Mathematics, University of Western Sydney, Sydney 2751 (Australia); Herman Shen, M.-H. [Department of Mechanical and Aerospace Engineering, The Ohio State University, OH 43210 (United States)

    2014-10-15

    In order to acquire the life information of organic light emitting diode (OLED), three groups of constant stress accelerated degradation tests are performed to obtain the luminance decaying data of samples under the condition that the luminance and the current are respectively selected as the indicator of performance degradation and the test stress. Weibull function is applied to describe the relationship between luminance decaying and time, least square method (LSM) is employed to calculate the shape parameter and scale parameter, and the life prediction of OLED is achieved. The numerical results indicate that the accelerated degradation test and the luminance decaying model reveal the luminance decaying law of OLED. The luminance decaying formula fits the test data very well, and the average error of fitting value compared with the test data is small. Furthermore, the accuracy of the OLED life predicted by luminance decaying model is high, which enable rapid estimation of OLED life and provide significant guidelines to help engineers make decisions in design and manufacturing strategy from the aspect of reliability life. - Highlights: • We gain luminance decaying data by accelerated degradation tests on OLED. • The luminance decaying model objectively reveals the decaying law of OLED luminance. • The least square method (LSM) is employed to calculate Weibull parameters. • The plan designed for accelerated degradation tests proves to be feasible. • The accuracy of the OLED life and the luminance decaying fitting formula is high.

  17. Life prediction of OLED for constant-stress accelerated degradation tests using luminance decaying model

    International Nuclear Information System (INIS)

    Zhang, Jianping; Li, Wenbin; Cheng, Guoliang; Chen, Xiao; Wu, Helen; Herman Shen, M.-H.

    2014-01-01

    In order to acquire the life information of organic light emitting diode (OLED), three groups of constant stress accelerated degradation tests are performed to obtain the luminance decaying data of samples under the condition that the luminance and the current are respectively selected as the indicator of performance degradation and the test stress. Weibull function is applied to describe the relationship between luminance decaying and time, least square method (LSM) is employed to calculate the shape parameter and scale parameter, and the life prediction of OLED is achieved. The numerical results indicate that the accelerated degradation test and the luminance decaying model reveal the luminance decaying law of OLED. The luminance decaying formula fits the test data very well, and the average error of fitting value compared with the test data is small. Furthermore, the accuracy of the OLED life predicted by luminance decaying model is high, which enable rapid estimation of OLED life and provide significant guidelines to help engineers make decisions in design and manufacturing strategy from the aspect of reliability life. - Highlights: • We gain luminance decaying data by accelerated degradation tests on OLED. • The luminance decaying model objectively reveals the decaying law of OLED luminance. • The least square method (LSM) is employed to calculate Weibull parameters. • The plan designed for accelerated degradation tests proves to be feasible. • The accuracy of the OLED life and the luminance decaying fitting formula is high

  18. Stochastic clustering of material surface under high-heat plasma load

    Science.gov (United States)

    Budaev, Viacheslav P.

    2017-11-01

    The results of a study of a surface formed by high-temperature plasma loads on various materials such as tungsten, carbon and stainless steel are presented. High-temperature plasma irradiation leads to an inhomogeneous stochastic clustering of the surface with self-similar granularity - fractality on the scale from nanoscale to macroscales. Cauliflower-like structure of tungsten and carbon materials are formed under high heat plasma load in fusion devices. The statistical characteristics of hierarchical granularity and scale invariance are estimated. They differ qualitatively from the roughness of the ordinary Brownian surface, which is possibly due to the universal mechanisms of stochastic clustering of material surface under the influence of high-temperature plasma.

  19. Planck early results. XXVI. Detection with Planck and confirmation by XMM-Newton of PLCK G266.6-27.3, an exceptionally X-ray luminous and massive galaxy cluster at z ~ 1

    DEFF Research Database (Denmark)

    Lähteenmäki, A.; Poutanen, T.; Natoli, P.

    2011-01-01

    We present first results on PLCKG266.6-27.3, a galaxy cluster candidate detected at a signal-to-noise ratio of 5 in the Planck All Sky survey. An XMM-Newton validation observation has allowed us to confirm that the candidate isa bona fide galaxy cluster. With these X-ray data we measure an accurate...

  20. Vacancy clustering behavior in hydrogen-charged martensitic steel AISI 410 under tensile deformation

    International Nuclear Information System (INIS)

    Sugita, K; Mutou, Y; Shirai, Y

    2016-01-01

    The formation and accumulation of defects under tensile deformation of hydrogen- charged AISI 410 martensitic steels were investigated by using positron lifetime spectroscopy. During the deformation process, dislocations and vacancy-clusters were introduced and increased with increasing strains. Between hydrogen-charged and uncharged samples with the same tensile strains there was no significant difference in the dislocation density and monovacancy equivalent vacancy density. (paper)

  1. Neutral molecular cluster formation of sulfuric acid–dimethylamine observed in real time under atmospheric conditions

    CERN Document Server

    Kürten, Andreas; Simon, Mario; Sipilä, Mikko; Sarnela, Nina; Junninen, Heikki; Adamov, Alexey; Almeida, João; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; Dommen, Josef; Donahue, Neil M; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Hutterli, Manuel; Kangasluoma, Juha; Kirkby, Jasper; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Makhmutov, Vladimir; Mathot, Serge; Onnela, Antti; Petäjä, Tuukka; Praplan, Arnaud P; Riccobono, Francesco; Rissanen, Matti P; Rondo, Linda; Schobesberger, Siegfried; Seinfeld, John H; Steiner, Gerhard; Tomé, António; Tröstl, Jasmin; Winkler, Paul M; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Baltensperger, Urs; Carslaw, Kenneth S; Kulmala, Markku; Worsnop, Douglas R; Curtius, Joachim

    2014-01-01

    For atmospheric sulfuric acid (SA) concentrations the presence of dimethylamine (DMA) at mixing ratios of several parts per trillion by volume can explain observed boundary layer new particle formation rates. However, the concentration and molecular composition of the neutral (uncharged) clusters have not been reported so far due to the lack of suitable instrumentation. Here we report on experiments from the Cosmics Leaving Outdoor Droplets chamber at the European Organization for Nuclear Research revealing the formation of neutral particles containing up to 14 SA and 16 DMA molecules, corresponding to a mobility diameter of about 2 nm, under atmospherically relevant conditions. These measurements bridge the gap between the molecular and particle perspectives of nucleation, revealing the fundamental processes involved in particle formation and growth. The neutral clusters are found to form at or close to the kinetic limit where particle formation is limited only by the collision rate of SA molecules. Even tho...

  2. Effect of Ionizing Radiation on Luminous Bacteria Cells

    International Nuclear Information System (INIS)

    Kudryasheva, N.; Rozhko, T.; Alexandrova, M.; Vasyunkina, E.; Arkhipova, V.

    2011-01-01

    Marine luminous bacteria were used to monitor toxicity of alpha- (Am-241, U-235+238) and beta- (tritium) radionuclide solutions. Increase or inhibition of bacterial luminescence was observed under exposure to radionuclides. Radiation toxicity of Am and chemical toxicity of U were demonstrated. Effects of U were similar to those of stable heavy metals: sensitivity was about 10-5 M. Sensitivity of the bacteria to Am-241 was 300 Bq/L (10 -11 M). Inhibition of bacterial growth was observed under exposure to Am-241 and tritium. Role of peroxides and electron transfer processes in the effects of radionuclides on luminous bacteria is discussed.

  3. Privacy-Preserving k-Means Clustering under Multiowner Setting in Distributed Cloud Environments

    Directory of Open Access Journals (Sweden)

    Hong Rong

    2017-01-01

    Full Text Available With the advent of big data era, clients who lack computational and storage resources tend to outsource data mining tasks to cloud service providers in order to improve efficiency and reduce costs. It is also increasingly common for clients to perform collaborative mining to maximize profits. However, due to the rise of privacy leakage issues, the data contributed by clients should be encrypted using their own keys. This paper focuses on privacy-preserving k-means clustering over the joint datasets encrypted under multiple keys. Unfortunately, existing outsourcing k-means protocols are impractical because not only are they restricted to a single key setting, but also they are inefficient and nonscalable for distributed cloud computing. To address these issues, we propose a set of privacy-preserving building blocks and outsourced k-means clustering protocol under Spark framework. Theoretical analysis shows that our scheme protects the confidentiality of the joint database and mining results, as well as access patterns under the standard semihonest model with relatively small computational overhead. Experimental evaluations on real datasets also demonstrate its efficiency improvements compared with existing approaches.

  4. Comparison of clinical outcomes between luminal invasive ductal carcinoma and luminal invasive lobular carcinoma.

    Science.gov (United States)

    Adachi, Yayoi; Ishiguro, Junko; Kotani, Haruru; Hisada, Tomoka; Ichikawa, Mari; Gondo, Naomi; Yoshimura, Akiyo; Kondo, Naoto; Hattori, Masaya; Sawaki, Masataka; Fujita, Takashi; Kikumori, Toyone; Yatabe, Yasushi; Kodera, Yasuhiro; Iwata, Hiroji

    2016-03-25

    The pathological and clinical features of invasive lobular carcinoma (ILC) differ from those of invasive ductal carcinoma (IDC). Several studies have indicated that patients with ILC have a better prognosis than those with ductal carcinoma. However, no previous study has considered the molecular subtypes and histological subtypes of ILC. We compared prognosis between IDC and classical, luminal type ILC and developed prognostic factors for early breast cancer patients with classical luminal ILC. Four thousand one hundred ten breast cancer patients were treated at the Aichi Cancer Center Hospital from 2003 to 2012. We identified 1,661 cases with luminal IDC and 105 cases with luminal classical ILC. We examined baseline characteristics, clinical outcomes, and prognostic factors of luminal ILC. The prognosis of luminal ILC was significantly worse than that of luminal IDC. The rates of 5-year disease free survival (DFS) were 91.9% and 88.4% for patients with luminal IDC and luminal ILC, respectively (P = 0.008). The rates of 5-year overall survival (OS) were 97.6% and 93.1% for patients with luminal IDC and luminal ILC respectively (P = 0.030). Although we analyzed prognosis according to stratification by tumor size, luminal ILC tended to have worse DFS than luminal IDC in the large tumor group. In addition, although our analysis was performed according to matching lymph node status, luminal ILC had a significantly worse DFS and OS than luminal IDC in node-positive patients. Survival curves showed that the prognosis for ILC became worse than IDC over time. Multivariate analysis showed that ILC was an important factor related to higher risk of recurrence of luminal type breast cancer, even when tumor size, lymph node status and histological grade were considered. Luminal ILC had worse outcomes than luminal IDC. Consequently, different treatment approaches should be used for luminal ILC than for luminal IDC.

  5. Modeling of 1D motion of interstitial clusters in iron under HVEM irradiation

    International Nuclear Information System (INIS)

    Satoh, Y.; Hamaoka, T.; Matsui, H.

    2007-01-01

    Full text of publication follows: We examined 1D motion of interstitial clusters in Fe under electron irradiation at room temperature using high voltage electron microscopy (HVEM). We found that some impurities have essential effects on the experimental 1D motion behavior. The characteristics of experimental 1D motion were obtained as follows: 1) 1D motion appears as discrete jumps (namely, stepwise positional changes) at irregular intervals. 2) Sometimes a set of several successive jumps occurs between certain two points (back and forth motion). 3) The frequency of 1D jumps is almost proportional to the electron beam intensity, while the distribution of 1D jump distance does not change much with the intensity. Very few 1D jumps are observed with a 200 kV TEM at room temperature. 4) The distance and the frequency of 1D jumps are greatly reduced in a specimen of low purities. Taking account for effects of impurities, we propose a mechanism of the experimental 1D jumps, as follows. Small interstitial clusters are regarded to be essentially mobile as crowdion bundles. Then interstitial clusters in a stationary state are trapped by impurity atom(s), due to elastic interactions between impurities and crowdion bundle. The electron irradiation changes the cluster into a mobile state by a detrapping: for example, the impurity atom is displaced to apart from the crowdion bundle. Then the crowdion bundle makes a free 1D migration until it is trapped by another impurity atom. Because of small activation energy for 1D migration, we cannot observe the detailed 1D random walk process, but a stepwise positional change from an impurity to another impurity. The average size of interstitial clusters observed in the present experiments was around 5 nm, corresponding to a bundle of 300 crowdions. In a rough estimate assuming that an impurity atom on any crowdion in the crowdion bundle prevent the migration of the bundle, the mean free path is about 75 nm and 7.5 nm at the impurity

  6. SURVEY OF THE ENTOMOFAUNA THROUGH LUMINOUS TRAP

    Directory of Open Access Journals (Sweden)

    V. R. Andrade Neto

    2014-09-01

    Full Text Available The demand for forest-based raw materials for energy, construction, paper pulp and the pressure to comply with legal requirements concerning environmental legislation, for example, the replacement of the permanent preservation area, legal reserve and recovery of degraded area, leads to encourage the production of healthy seedlings in a health status to do not compromise their future production. The present study aimed to survey the entomofauna population using the “Luiz de Queiroz” model of luminous trap, with white and red fluorescent lamps. The experiment was conducted at the nursery “Flora Sinop” in Sinop – MT. The survey was conducted weekly between the months of April to July 2010, totaling 4 months sand, 32 samples collected. The orders Hemiptera and Coleoptera showed the highest number of individuals captured, either in attraction with white or red light. It was captured 10.089 individuals, 9.339 collected under the influence of white light, representing 92,56%, and 750 with red light, only 7,44% of the total. The white light luminous trap possessed greater efficiency in the attraction of insects when compared with the red light trap.

  7. The luminous and the grey

    CERN Document Server

    Batchelor, David

    2014-01-01

    Color surrounds us: the lush green hues of trees and grasses, the variant blues of water and the sky, the bright pops of yellow and red from flowers. But at the same time, color lies at the limits of language and understanding. In this absorbing sequel to Chromophobia-which addresses the extremes of love and loathing provoked by color since antiquity-David Batchelor charts color's more ambiguous terrain.   The Luminous and the Grey explores the places where color comes into being and where it fades away, probing when it begins and when it ends both in the imagination and in the material world.

  8. Influence of the electron density on the characteristics of terahertz waves generated under laser–cluster interaction

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, A. A., E-mail: frolov@ihed.ras.ru [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2016-12-15

    A theory of generation of terahertz radiation under laser–cluster interaction, developed earlier for an overdense cluster plasma [A. A. Frolov, Plasma Phys. Rep. 42. 637 (2016)], is generalized for the case of arbitrary electron density. The spectral composition of radiation is shown to substantially depend on the density of free electrons in the cluster. For an underdense cluster plasma, there is a sharp peak in the terahertz spectrum at the frequency of the quadrupole mode of a plasma sphere. As the electron density increases to supercritical values, this spectral line vanishes and a broad maximum at the frequency comparable with the reciprocal of the laser pulse duration appears in the spectrum. The dependence of the total energy of terahertz radiation on the density of free electrons is analyzed. The radiation yield is shown to increase significantly under resonance conditions, when the laser frequency is close to the eigenfrequency of the dipole or quadrupole mode of a plasma sphere.

  9. Damage evolution analysis of coal samples under cyclic loading based on single-link cluster method

    Science.gov (United States)

    Zhang, Zhibo; Wang, Enyuan; Li, Nan; Li, Xuelong; Wang, Xiaoran; Li, Zhonghui

    2018-05-01

    In this paper, the acoustic emission (AE) response of coal samples under cyclic loading is measured. The results show that there is good positive relation between AE parameters and stress. The AE signal of coal samples under cyclic loading exhibits an obvious Kaiser Effect. The single-link cluster (SLC) method is applied to analyze the spatial evolution characteristics of AE events and the damage evolution process of coal samples. It is found that a subset scale of the SLC structure becomes smaller and smaller when the number of cyclic loading increases, and there is a negative linear relationship between the subset scale and the degree of damage. The spatial correlation length ξ of an SLC structure is calculated. The results show that ξ fluctuates around a certain value from the second cyclic loading process to the fifth cyclic loading process, but spatial correlation length ξ clearly increases in the sixth loading process. Based on the criterion of microcrack density, the coal sample failure process is the transformation from small-scale damage to large-scale damage, which is the reason for changes in the spatial correlation length. Through a systematic analysis, the SLC method is an effective method to research the damage evolution process of coal samples under cyclic loading, and will provide important reference values for studying coal bursts.

  10. Brightest Cluster Galaxies in REXCESS Clusters

    Science.gov (United States)

    Haarsma, Deborah B.; Leisman, L.; Bruch, S.; Donahue, M.

    2009-01-01

    Most galaxy clusters contain a Brightest Cluster Galaxy (BCG) which is larger than the other cluster ellipticals and has a more extended profile. In the hierarchical model, the BCG forms through many galaxy mergers in the crowded center of the cluster, and thus its properties give insight into the assembly of the cluster as a whole. In this project, we are working with the Representative XMM-Newton Cluster Structure Survey (REXCESS) team (Boehringer et al 2007) to study BCGs in 33 X-ray luminous galaxy clusters, 0.055 < z < 0.183. We are imaging the BCGs in R band at the Southern Observatory for Astrophysical Research (SOAR) in Chile. In this poster, we discuss our methods and give preliminary measurements of the BCG magnitudes, morphology, and stellar mass. We compare these BCG properties with the properties of their host clusters, particularly of the X-ray emitting gas.

  11. Optimization Approach for Multi-scale Segmentation of Remotely Sensed Imagery under k-means Clustering Guidance

    Directory of Open Access Journals (Sweden)

    WANG Huixian

    2015-05-01

    Full Text Available In order to adapt different scale land cover segmentation, an optimized approach under the guidance of k-means clustering for multi-scale segmentation is proposed. At first, small scale segmentation and k-means clustering are used to process the original images; then the result of k-means clustering is used to guide objects merging procedure, in which Otsu threshold method is used to automatically select the impact factor of k-means clustering; finally we obtain the segmentation results which are applicable to different scale objects. FNEA method is taken for an example and segmentation experiments are done using a simulated image and a real remote sensing image from GeoEye-1 satellite, qualitative and quantitative evaluation demonstrates that the proposed method can obtain high quality segmentation results.

  12. Comparison of clinical outcomes between luminal invasive ductal carcinoma and luminal invasive lobular carcinoma

    International Nuclear Information System (INIS)

    Adachi, Yayoi; Ishiguro, Junko; Kotani, Haruru; Hisada, Tomoka; Ichikawa, Mari; Gondo, Naomi; Yoshimura, Akiyo; Kondo, Naoto; Hattori, Masaya; Sawaki, Masataka; Fujita, Takashi; Kikumori, Toyone; Yatabe, Yasushi; Kodera, Yasuhiro; Iwata, Hiroji

    2016-01-01

    The pathological and clinical features of invasive lobular carcinoma (ILC) differ from those of invasive ductal carcinoma (IDC). Several studies have indicated that patients with ILC have a better prognosis than those with ductal carcinoma. However, no previous study has considered the molecular subtypes and histological subtypes of ILC. We compared prognosis between IDC and classical, luminal type ILC and developed prognostic factors for early breast cancer patients with classical luminal ILC. Four thousand one hundred ten breast cancer patients were treated at the Aichi Cancer Center Hospital from 2003 to 2012. We identified 1,661 cases with luminal IDC and 105 cases with luminal classical ILC. We examined baseline characteristics, clinical outcomes, and prognostic factors of luminal ILC. The prognosis of luminal ILC was significantly worse than that of luminal IDC. The rates of 5-year disease free survival (DFS) were 91.9 % and 88.4 % for patients with luminal IDC and luminal ILC, respectively (P = 0.008). The rates of 5-year overall survival (OS) were 97.6 % and 93.1 % for patients with luminal IDC and luminal ILC respectively (P = 0.030). Although we analyzed prognosis according to stratification by tumor size, luminal ILC tended to have worse DFS than luminal IDC in the large tumor group. In addition, although our analysis was performed according to matching lymph node status, luminal ILC had a significantly worse DFS and OS than luminal IDC in node-positive patients. Survival curves showed that the prognosis for ILC became worse than IDC over time. Multivariate analysis showed that ILC was an important factor related to higher risk of recurrence of luminal type breast cancer, even when tumor size, lymph node status and histological grade were considered. Luminal ILC had worse outcomes than luminal IDC. Consequently, different treatment approaches should be used for luminal ILC than for luminal IDC. The online version of this article (doi:10.1186/s12885

  13. SI 1985 No. 1048 - The Radioactive Substances (Luminous Articles) Exemption Order 1985

    International Nuclear Information System (INIS)

    1985-01-01

    This Order, which came into force on 17 September 1985, is concerned with exemptions and exclusions under the Radioactive Substances Act 1960 in respect of radioactive luminous instruments and indicators. (NEA) [fr

  14. Weighted Clustering

    DEFF Research Database (Denmark)

    Ackerman, Margareta; Ben-David, Shai; Branzei, Simina

    2012-01-01

    We investigate a natural generalization of the classical clustering problem, considering clustering tasks in which different instances may have different weights.We conduct the first extensive theoretical analysis on the influence of weighted data on standard clustering algorithms in both...... the partitional and hierarchical settings, characterizing the conditions under which algorithms react to weights. Extending a recent framework for clustering algorithm selection, we propose intuitive properties that would allow users to choose between clustering algorithms in the weighted setting and classify...

  15. Cluster-cluster clustering

    International Nuclear Information System (INIS)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C.S.; Yale Univ., New Haven, CT; California Univ., Santa Barbara; Cambridge Univ., England; Sussex Univ., Brighton, England)

    1985-01-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales. 30 references

  16. Transformation dynamics of Ni clusters into NiO rings under electron beam irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Knez, Daniel, E-mail: daniel.knez@felmi-zfe.at [Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz (Austria); Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz (Austria); Thaler, Philipp; Volk, Alexander [Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria); Kothleitner, Gerald [Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz (Austria); Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz (Austria); Ernst, Wolfgang E. [Institute of Experimental Physics, Graz University of Technology, Petersgasse 16, 8010 Graz (Austria); Hofer, Ferdinand [Institute of Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz (Austria); Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz (Austria)

    2017-05-15

    We report the transformation of nickel clusters into NiO rings by an electron beam induced nanoscale Kirkendall effect. High-purity nickel clusters consisting of a few thousand atoms have been used as precursors and were synthesized with the superfluid helium droplet technique. Aberration-corrected, analytical scanning transmission electron microscopy was applied to oxidise and simultaneously analyse the nanostructures. The transient dynamics of the oxidation could be documented by time lapse series using high-angle annular dark-field imaging and electron energy-loss spectroscopy. A two-step Cabrera-Mott oxidation mechanism was identified. It was found that water adsorbed adjacent to the clusters acts as oxygen source for the electron beam induced oxidation. The size-dependent oxidation rate was estimated by quantitative EELS measurements combined with molecular dynamics simulations. Our findings could serve to better control sample changes during examination in an electron microscope, and might provide a methodology to generate other metal oxide nanostructures. - Highlights: • Beam induced conversion of Ni clusters into crystalline NiO rings has been observed. • Ni clusters were grown with the superfluid He-droplet technique. • oxidizeSTEM was utilized to investigate and simultaneously oxidize these clusters. • Oxidation dynamics was captured in real-time. • Cluster sizes and the oxidation rate were estimated via EELS and molecular dynamics.

  17. Physiological characteristics of high yield under cluster planting: photosynthesis and canopy microclimate of cotton

    Directory of Open Access Journals (Sweden)

    Ting-ting Xie

    2016-01-01

    Full Text Available Cotton produces more biomass and economic yield when cluster planting pattern (three plants per hole than in a traditional planting pattern (one plant per hole, even at similar plant densities, indicating that individual plant growth is promoted by cluster planting. The causal factors for this improved growth induced by cluster planting pattern, the light interception, canopy microclimate and photosynthetic rate of cotton were investigated in an arid region of China. The results indicated that the leaf area index and light interception were higher in cluster planting, and significantly different from those in traditional planting during the middle and late growth stages. Cotton canopy humidity at different growth stages was increased but canopy temperatures were reduced by cluster planting. In the later growth stage of cluster planting, the leaf chlorophyll content was higher and the leaf net photosynthetic rate and canopy photosynthetic rate were significantly increased in comparing with traditional planting pattern. We concluded that differences in canopy light interception and photosynthetic rate were the primary factors responsible for increased biomass production and economic yield in cluster planting compared with the traditional planting of cotton.

  18. Effect of impurities on the growth of {113} interstitial clusters in silicon under electron irradiation

    OpenAIRE

    Nakai, K.; Hamada, K.; Satoh, Y.; Yoshiie, T.

    2011-01-01

    The growth and shrinkage of interstitial clusters on {113} planes were investigated in electron irradiated Czochralski grown silicon (Cz-Si), floating-zone silicon (Fz-Si), and impurity-doped Fz-Si (HT-Fz-Si) using a high voltage electron microscope. In Fz-Si, {113} interstitial clusters were formed only near the beam incident surface after a long incubation period, and shrank on subsequent irradiation from the backside of the specimen. In Cz-Si and HT-Fz-Si, {113} interstitial clusters nucle...

  19. Luminous Phenomena - A Scientific Investigation of Anomalous Luminous Atmospheric Phenomena

    Science.gov (United States)

    Teodorani, M.

    2003-12-01

    Anomalous atmospheric luminous phenomena reoccur in several locations of Earth, in the form of multi-color light balls characterized by large dimensions, erratic motion, long duration and a correlated electromagnetic field. The author (an astrophysicist) of this book, which is organized as a selection of some of his technical and popularizing papers and seminars, describes and discusses all the efforts that have been done in 10 years, through several missions and a massive data analysis, in order to obtain some scientific explanation of this kind of anomalies, in particular the Hessdalen anomaly in Norway. The following topics are treated in the book: a) geographic archive of the areas of Earth where such phenomena are known to reoccur most often; b) observational techniques of astrophysical kind that have been used to acquire the data; c) main scientific results obtained so far; d) physical interpretation and natural hypothesis vs. ETV hypothesis; e) historical and chronological issues; f) the importance to brindle new energy sources; g) the importance to keep distance from any kind of "ufology". An unpublished chapter is entirely devoted to a detailed scientific investigation project of light phenomena reoccurring on the Ontario lake; the chosen new-generation multi-wavelength sensing instrumentation that is planned to be used in future missions in that specific area, is described together with scientific rationale and planned procedures. The main results, which were obtained in other areas of the world, such as the Arizona desert, USA and the Sibillini Mountains, Italy, are also briefly mentioned. One chapter is entirely dedicated to the presentation of extensive abstracts of technical papers by the author concerning this specific subject. The book is accompanied with a rich source of bibliographic references.

  20. Luminance and chromatic contributions to a hyperacuity task: isolation by contrast polarity and target separation.

    Science.gov (United States)

    Sun, Hao; Cooper, Bonnie; Lee, Barry B

    2012-03-01

    Vernier thresholds are known to be elevated when a target pair has opposite contrast polarity. Polarity reversal is used to assess the role of luminance and chromatic pathways in hyperacuity performance. Psychophysical hyperacuity thresholds were measured for pairs of gratings of various combinations of luminance (Lum) and chromatic (Chr) contrast polarities, at different ratios of luminance to chromatic contrast. With two red-green gratings of matched luminance and chromatic polarity (+Lum+Chr), there was an elevation of threshold at isoluminance. When both luminance and chromatic polarity were mismatched (-Lum-Chr), thresholds were substantially elevated under all conditions. With the same luminance contrast polarity and opposite chromatic polarity (+Lum-Chr) thresholds were only elevated close to isoluminance; in the reverse condition (-Lum+Chr), thresholds were elevated as in the -Lum-Chr condition except close to equiluminance. Similar data were obtained for gratings isolating the short-wavelength cone mechanism. Further psychophysical measurements assessed the role of target separation with matched or mismatched contrast polarity; similar results were found for luminance and chromatic gratings. Comparison physiological data were collected from parafoveal ganglion cells of the macaque retina. Positional precision of ganglion cell signals was assessed under conditions related to the psychophysical measurements. On the basis of these combined observations, it is argued that both magnocellular, parvocellular, and koniocellular pathways have access to cortical positional mechanisms associated with vernier acuity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. PARTIAL TRAINING METHOD FOR HEURISTIC ALGORITHM OF POSSIBLE CLUSTERIZATION UNDER UNKNOWN NUMBER OF CLASSES

    Directory of Open Access Journals (Sweden)

    D. A. Viattchenin

    2009-01-01

    Full Text Available A method for constructing a subset of labeled objects which is used in a heuristic algorithm of possible  clusterization with partial  training is proposed in the  paper.  The  method  is  based  on  data preprocessing by the heuristic algorithm of possible clusterization using a transitive closure of a fuzzy tolerance. Method efficiency is demonstrated by way of an illustrative example.

  2. Daylight calculations using constant luminance curves

    Energy Technology Data Exchange (ETDEWEB)

    Betman, E. [CRICYT, Mendoza (Argentina). Laboratorio de Ambiente Humano y Vivienda

    2005-02-01

    This paper presents a simple method to manually estimate daylight availability and to make daylight calculations using constant luminance curves calculated with local illuminance and irradiance data and the all-weather model for sky luminance distribution developed in the Atmospheric Science Research Center of the University of New York (ARSC) by Richard Perez et al. Work with constant luminance curves has the advantage that daylight calculations include the problem's directionality and preserve the information of the luminous climate of the place. This permits accurate knowledge of the resource and a strong basis to establish conclusions concerning topics related to the energy efficiency and comfort in buildings. The characteristics of the proposed method are compared with the method that uses the daylight factor. (author)

  3. EVOLUTION OF THE MOST LUMINOUS DUSTY GALAXIES

    International Nuclear Information System (INIS)

    Weedman, Daniel W.; Houck, James R.

    2009-01-01

    A summary of mid-infrared continuum luminosities arising from dust is given for very luminous galaxies, L IR > 10 12 L sun , with 0.005 0.7 in the 9.7 μm silicate absorption feature (i.e., half of the continuum is absorbed) and having equivalent width of the 6.2 μm polycyclic aromatic hydrocarbon feature ν (8 μm) for the most luminous obscured AGNs is found to scale as (1+z) 2.6 to z = 2.8. For unobscured AGNs, the scaling with redshift is similar, but luminosities νL ν (8 μm) are approximately three times greater for the most luminous sources. Using both obscured and unobscured AGNs having total infrared fluxes from the Infrared Astronomical Satellite, empirical relations are found between νL ν (8 μm) and L IR . Combining these relations with the redshift scaling of luminosity, we conclude that the total infrared luminosities for the most luminous obscured AGNs, L IR (AGN obscured ) in L sun , scale as log L IR (AGN obscured ) = 12.3 ± 0.25 + 2.6(±0.3)log(1+z), and for the most luminous unobscured AGNs, scale as log L IR (AGN1) = 12.6(±0.15) + 2.6(±0.3)log(1+z). We previously determined that the most luminous starbursts scale as log L IR (SB) = 11.8 ± 0.3 + 2.5(±0.3)log(1+z), indicating that the most luminous AGNs are about 10 times more luminous than the most luminous starbursts. Results are consistent with obscured and unobscured AGNs having the same total luminosities with differences arising only from orientation, such that the obscured AGNs are observed through very dusty clouds which extinct about 50% of the intrinsic luminosity at 8 μm. Extrapolations of observable f ν (24 μm) to z = 6 are made using evolution results for these luminous sources. Both obscured and unobscured AGNs should be detected to z ∼ 6 by Spitzer surveys with f ν (24 μm) > 0.3 mJy, even without luminosity evolution for z > 2.5. By contrast, the most luminous starbursts cannot be detected for z > 3, even if luminosity evolution continues beyond z = 2.5.

  4. The impact of luminance on tonic and phasic pupillary responses to sustained cognitive load.

    Science.gov (United States)

    Peysakhovich, Vsevolod; Vachon, François; Dehais, Frédéric

    2017-02-01

    Pupillary reactions independent of light conditions have been linked to cognition for a long time. However, the light conditions can impact the cognitive pupillary reaction. Previous studies underlined the impact of luminance on pupillary reaction, but it is still unclear how luminance modulates the sustained and transient components of pupillary reaction - tonic pupil diameter and phasic pupil response. In the present study, we investigated the impact of the luminance on these two components under sustained cognitive load. Fourteen participants performed a novel working memory task combining mathematical computations with a classic n-back task. We studied both tonic pupil diameter and phasic pupil response under low (1-back) and high (2-back) working memory load and two luminance levels (gray and white). We found that the impact of working memory load on the tonic pupil diameter was modulated by the level of luminance, the increase in tonic pupil diameter with the load being larger under lower luminance. In contrast, the smaller phasic pupil response found under high load remained unaffected by luminance. These results showed that luminance impacts the cognitive pupillary reaction - tonic pupil diameter (phasic pupil response) being modulated under sustained (respectively, transient) cognitive load. These findings also support the relationship between the locus-coeruleus system, presumably functioning in two firing modes - tonic and phasic - and the pupil diameter. We suggest that the tonic pupil diameter tracks the tonic activity of the locus-coeruleus while phasic pupil response reflects its phasic activity. Besides, the designed novel cognitive paradigm allows the simultaneous manipulation of sustained and transient components of the cognitive load and is useful for dissociating the effects on the tonic pupil diameter and phasic pupil response. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Simultaneous chromatic and luminance human electroretinogram responses.

    Science.gov (United States)

    Parry, Neil R A; Murray, Ian J; Panorgias, Athanasios; McKeefry, Declan J; Lee, Barry B; Kremers, Jan

    2012-07-01

    The parallel processing of information forms an important organisational principle of the primate visual system. Here we describe experiments which use a novel chromatic–achromatic temporal compound stimulus to simultaneously identify colour and luminance specific signals in the human electroretinogram (ERG). Luminance and chromatic components are separated in the stimulus; the luminance modulation has twice the temporal frequency of the chromatic modulation. ERGs were recorded from four trichromatic and two dichromatic subjects (1 deuteranope and 1 protanope). At isoluminance, the fundamental (first harmonic) response was elicited by the chromatic component in the stimulus. The trichromatic ERGs possessed low-pass temporal tuning characteristics, reflecting the activity of parvocellular post-receptoral mechanisms. There was very little first harmonic response in the dichromats' ERGs. The second harmonic response was elicited by the luminance modulation in the compound stimulus and showed, in all subjects, band-pass temporal tuning characteristic of magnocellular activity. Thus it is possible to concurrently elicit ERG responses from the human retina which reflect processing in both chromatic and luminance pathways. As well as providing a clear demonstration of the parallel nature of chromatic and luminance processing in the human retina, the differences that exist between ERGs from trichromatic and dichromatic subjects point to the existence of interactions between afferent post-receptoral pathways that are in operation from the earliest stages of visual processing.

  6. Signs of depth-luminance covariance in 3-D cluttered scenes.

    Science.gov (United States)

    Scaccia, Milena; Langer, Michael S

    2018-03-01

    In three-dimensional (3-D) cluttered scenes such as foliage, deeper surfaces often are more shadowed and hence darker, and so depth and luminance often have negative covariance. We examined whether the sign of depth-luminance covariance plays a role in depth perception in 3-D clutter. We compared scenes rendered with negative and positive depth-luminance covariance where positive covariance means that deeper surfaces are brighter and negative covariance means deeper surfaces are darker. For each scene, the sign of the depth-luminance covariance was given by occlusion cues. We tested whether subjects could use this sign information to judge the depth order of two target surfaces embedded in 3-D clutter. The clutter consisted of distractor surfaces that were randomly distributed in a 3-D volume. We tested three independent variables: the sign of the depth-luminance covariance, the colors of the targets and distractors, and the background luminance. An analysis of variance showed two main effects: Subjects performed better when the deeper surfaces were darker and when the color of the target surfaces was the same as the color of the distractors. There was also a strong interaction: Subjects performed better under a negative depth-luminance covariance condition when targets and distractors had different colors than when they had the same color. Our results are consistent with a "dark means deep" rule, but the use of this rule depends on the similarity between the color of the targets and color of the 3-D clutter.

  7. Performance study of a cluster calculation; parallelization and application under geant4

    International Nuclear Information System (INIS)

    Trabelsi, Abir

    2007-01-01

    This work concretizes the final studies project for engineering computer sciences, it is archived within the national center of nuclear sciences and technology. The project consists in studying the performance of a set of machines in order to determine the best architecture to assemble them in a cluster. As well as the parallelism and the parallel implementation of GEANT4, as a tool of simulation. The realisation of this project consists on : 1) programming with C++ and executing the two benchmarks P MV and PMM on each station; 2) Interpreting this result in order to show the best architecture of the cluster; 3) parallelism with TOP-C the two benchmarks; 4) Executing the two Top-C versions on the cluster; 5) Generalizing this results; 6)parallelism et executing the parallel version of GEANT4. (Author). 14 refs

  8. Investigation of energy thresholds of atomic and cluster sputtering of some elements under ion bombardment

    CERN Document Server

    Atabaev, B G; Lifanova, L F

    2002-01-01

    Threshold energies of sputtering of negative cluster ions from the Si(111) surface were measured at bombardment by Cs sup + , Rb sup + , and Na sup + ions with energy of 0.1-3.0 keV. These results are compared with the calculations of the similar thresholds by Bohdansky etc. formulas (3) for clusters Si sub n sup - and Cu sub n sup - with n=(1-5) and also for B, C, Al, Si, Fe, Cu atoms. Threshold energies of sputtering for the above elements were also estimated using the data from (5). Satisfactory agreement between the experimental and theoretical results was obtained. (author)

  9. Cluster size influence on the survivability of Rhipicephalus Boophilus microplus larvae under low relative humidity stress

    Science.gov (United States)

    Low relative humidity (RH) levels (=63%) have been previously shown to be a determining factor in the survival of southern cattle fever tick, Rhipicephalus microplus, larvae, regardless of temperature. Supporting this observation, large larval clusters can retain more water than isolated larvae. Th...

  10. Cluster observations of continuous reconnection at the magnetopause under steady interplanetary magnetic field conditions

    Directory of Open Access Journals (Sweden)

    T. D. Phan

    2004-07-01

    Full Text Available On 26 January 2001, the Cluster spacecraft detected high-speed plasma jets at multiple crossings of the high-latitude duskside magnetopause (MP and boundary layer (BL over a period of more than 2h. The 4 spacecraft combined spent more than half of this time in the MP/BL and jets were observed whenever a spacecraft was in the MP. These observations were made under steady southward and dawnward interplanetary magnetic field (IMF conditions. The magnetic shear across the local MP was ~100° and β~1 in the adjacent magnetosheath. The jet velocity is in remarkable agreement with reconnection prediction throughout the entire interval, except for one crossing that had no ion measurements inside the current layer. The flow speed measured in the deHoffmann Teller frame is 90% of the Alfvén speed on average for the 10 complete MP current layer crossings that are resolved by the ion measurements. These findings strongly suggest that reconnection was continuously active for more than two hours. The jets were directed persistently in the same northward and anti-sunward direction, implying that the X-line was always below the spacecraft. This feature is inconsistent with patchy and random reconnection or convecting multiple X-lines. The majority of MP/BL crossings in this two-hour interval were partial crossings, implying that they are caused by bulges sliding along the MP, not by inward-outward motion of a uniformly thin MP/BL. The presence of the bulges suggests that, although reconnection is continuously active under steady IMF conditions, its rate may be modulated. The present investigation also reveals that (1 the predicted ion D-shaped distributions are absent in all reconnection jets on this day, (2 the electric field fluctuations are larger in the reconnecting MP than in the magnetosheath proper, but their amplitudes never exceed 20mV/m, (3 the ion-electron differential motion is ~20km/s for the observed MP current density of ~50nA/m2 (∇× B, thus

  11. Coulomb frustration of the multiphoton ionization of metallic clusters under intense EUV FEL evidenced by ion spectrometry

    International Nuclear Information System (INIS)

    Mazza, T; Devetta, M; Milani, P; Motomura, K; Liu, X-J; Fukuzawa, H; Yamada, A; Nagaya, K; Iwayama, H; Sugishima, A; Mizoguchi, Y; Saito, N; Coreno, M; Nagasono, M; Tono, K; Togashi, T; Kimura, H; Okunishi, M; Fennel, Th; Senba, Y

    2015-01-01

    Free electron laser light sources delivering high intensity pulses of short wavelength radiation are opening novel possibilities for the investigation of matter at the nanoscale and for the discovery and understanding of new physical processes occurring at the exotic transient states they make accessible. Strong ionization of atomic constituents of a nano-sized sample is a representative example of such processes and the understanding of ionization dynamics is crucial for a realistic description of the experiments. We report here on multiple ionization experiments on free clusters of titanium, a high cohesive energy metal. The time of flight ion spectra reveal a saturation of the cluster ionization at ∼10 16 photons per pulse per cm 2 . Our results also show a clear lack of any explosion process, opposite to what is observed for a rare-gas cluster under similar conditions. A simple and generalized multi-step ionization model including Coulomb frustration of the photoemission process effectively reproduces with a good agreement the main features of the experimental observation and points to an interpretation of the data involving a substantial energy deposition into the cluster through electronic system heating upon scattering events within photoemission. (paper)

  12. Luminous quasars do not live in the most overdense regions of galaxies at z ˜ 4

    Science.gov (United States)

    Uchiyama, Hisakazu; Toshikawa, Jun; Kashikawa, Nobunari; Overzier, Roderik; Chiang, Yi-Kuan; Marinello, Murilo; Tanaka, Masayuki; Niino, Yuu; Ishikawa, Shogo; Onoue, Masafusa; Ichikawa, Kohei; Akiyama, Masayuki; Coupon, Jean; Harikane, Yuichi; Imanishi, Masatoshi; Kodama, Tadayuki; Komiyama, Yutaka; Lee, Chien-Hsiu; Lin, Yen-Ting; Miyazaki, Satoshi; Nagao, Tohru; Nishizawa, Atsushi J.; Ono, Yoshiaki; Ouchi, Masami; Wang, Shiang-Yu

    2018-01-01

    We present the cross-correlation between 151 luminous quasars (MUV 4 σ. The distributions of the distances between quasars and the nearest protoclusters and the significance of the overdensity at the positions of quasars are statistically identical to those found for g-dropout galaxies, suggesting that quasars tend to reside in almost the same environment as star-forming galaxies at this redshift. Using stacking analysis, we find that the average density of g-dropout galaxies around quasars is slightly higher than that around g-dropout galaxies on 1.0-2.5 pMpc scales, while at anti-correlated with overdensity. These findings are consistent with a scenario in which luminous quasars at z ˜ 4 reside in structures that are less massive than those expected for the progenitors of today's rich clusters of galaxies, and possibly that luminous quasars may be suppressing star formation in their close vicinity.

  13. Measuring high-resolution sky luminance distributions with a CCD camera.

    Science.gov (United States)

    Tohsing, Korntip; Schrempf, Michael; Riechelmann, Stefan; Schilke, Holger; Seckmeyer, Gunther

    2013-03-10

    We describe how sky luminance can be derived from a newly developed hemispherical sky imager (HSI) system. The system contains a commercial compact charge coupled device (CCD) camera equipped with a fish-eye lens. The projection of the camera system has been found to be nearly equidistant. The luminance from the high dynamic range images has been calculated and then validated with luminance data measured by a CCD array spectroradiometer. The deviation between both datasets is less than 10% for cloudless and completely overcast skies, and differs by no more than 20% for all sky conditions. The global illuminance derived from the HSI pictures deviates by less than 5% and 20% under cloudless and cloudy skies for solar zenith angles less than 80°, respectively. This system is therefore capable of measuring sky luminance with the high spatial and temporal resolution of more than a million pixels and every 20 s respectively.

  14. Research on the calibration methods of the luminance parameter of radiation luminance meters

    Science.gov (United States)

    Cheng, Weihai; Huang, Biyong; Lin, Fangsheng; Li, Tiecheng; Yin, Dejin; Lai, Lei

    2017-10-01

    This paper introduces standard diffusion reflection white plate method and integrating sphere standard luminance source method to calibrate the luminance parameter. The paper compares the effects of calibration results by using these two methods through principle analysis and experimental verification. After using two methods to calibrate the same radiation luminance meter, the data obtained verifies the testing results of the two methods are both reliable. The results show that the display value using standard white plate method has fewer errors and better reproducibility. However, standard luminance source method is more convenient and suitable for on-site calibration. Moreover, standard luminance source method has wider range and can test the linear performance of the instruments.

  15. Study on the Influence Factors of the Luminous Intensity of the Long Afterglow Luminous Paints

    Directory of Open Access Journals (Sweden)

    Zhao Su

    2016-01-01

    Full Text Available In order to extend the time afterglow luminous powder, enhancement the brightness of luminous paint, this study explore affect long afterglow energy storage luminous paints brightness of the main factors. Luminous paints were prepared with rare earth aluminate long afterglow luminescent powder, first is luminous powder surface modification, then investigate the influence of light emitting powder content, calcium carbonate, titanium dioxide, nano alumina and other fillers on the luminescent properties of the paints. It was concluded that the water resistance of the luminescent powder is better and the brightness can be improved after the modification of anhydrous alcohol. The addition of nano-alumina can improve the brightness of the system, and can effectively enhance the hardness of the paints. In the paints, the two kinds of components of carbonate and titanium dioxide have little effect on the luminescent brightness of the painting.

  16. Polymerization of solid C60 under C60 cluster ion bombardment

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.; Narumi, K.

    2009-01-01

    Roč. 95, - (2009), s. 867-873 ISSN 0947-8396 R&D Projects: GA AV ČR(CZ) KAN400480701; GA MŠk(CZ) LC06041 Institutional research plan: CEZ:AV0Z10480505 Keywords : fulleren * cluster * bombardment * polymerization Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.595, year: 2009 http://www.springerlink.com/content/0947-8396

  17. A High-Resolution Cluster of Oceanographic Instruments for Boundary Layer Measurements under Ice.

    Science.gov (United States)

    1985-11-01

    arrangement for use with laser velocimetry. The EO components are mounted on an aluminum chassis, which is in turn placed in an underwater housing made...temperature/conductivity probe pair used * on the HRC cluster. It consists of a thermistor probe (FASTIP, Model FP07, Thermometrics , Inc.) and a dual...component. The orientation of all three DLT)V pairs is shown in Figure 1. 3.2 Temperature and Conductivity Probes The FASTIP thermistor by Thermometrics

  18. Environmental filtering of eudicot lineages underlies phylogenetic clustering in tropical South American flooded forests.

    Science.gov (United States)

    Aldana, Ana M; Carlucci, Marcos B; Fine, Paul V A; Stevenson, Pablo R

    2017-02-01

    The phylogenetic community assembly approach has been used to elucidate the role of ecological and historical processes in shaping tropical tree communities. Recent studies have shown that stressful environments, such as seasonally dry, white-sand and flooded forests tend to be phylogenetically clustered, arguing for niche conservatism as the main driver for this pattern. Very few studies have attempted to identify the lineages that contribute to such assembly patterns. We aimed to improve our understanding of the assembly of flooded forest tree communities in Northern South America by asking the following questions: are seasonally flooded forests phylogenetically clustered? If so, which angiosperm lineages are over-represented in seasonally flooded forests? To assess our hypotheses, we investigated seasonally flooded and terra firme forests from the Magdalena, Orinoco and Amazon Basins, in Colombia. Our results show that, regardless of the river basin in which they are located, seasonally flooded forests of Northern South America tend to be phylogenetically clustered, which means that the more abundant taxa in these forests are more closely related to each other than expected by chance. Based on our alpha and beta phylodiversity analyses we interpret that eudicots are more likely to adapt to extreme environments such as seasonally flooded forests, which indicates the importance of environmental filtering in the assembly of the Neotropical flora.

  19. MRI texture analysis in differentiating luminal A and luminal B breast cancer molecular subtypes - a feasibility study.

    Science.gov (United States)

    Holli-Helenius, Kirsi; Salminen, Annukka; Rinta-Kiikka, Irina; Koskivuo, Ilkka; Brück, Nina; Boström, Pia; Parkkola, Riitta

    2017-12-29

    The aim of this study was to use texture analysis (TA) of breast magnetic resonance (MR) images to assist in differentiating estrogen receptor (ER) positive breast cancer molecular subtypes. Twenty-seven patients with histopathologically proven invasive ductal breast cancer were selected in preliminary study. Tumors were classified into molecular subtypes: luminal A (ER-positive and/or progesterone receptor (PR)-positive, human epidermal growth factor receptor type 2 (HER2) -negative, proliferation marker Ki-67 MaZda. Texture parameters and tumour volumes were correlated with tumour prognostic factors. Textural differences were observed mainly in precontrast images. The two most discriminative texture parameters to differentiate luminal A and luminal B subtypes were sum entropy and sum variance (p = 0.003). The AUCs were 0.828 for sum entropy (p = 0.004), and 0.833 for sum variance (p = 0.003), and 0.878 for the model combining texture features sum entropy, sum variance (p = 0.001). In the LOOCV, the AUC for model combining features sum entropy and sum variance was 0.876. Sum entropy and sum variance showed positive correlation with higher Ki-67 index. Luminal B types were larger in volume and moderate correlation between larger tumour volume and higher Ki-67 index was also observed (r = 0.499, p = 0.008). Texture features which measure randomness, heterogeneity or smoothness and homogeneity may either directly or indirectly reflect underlying growth patterns of breast tumours. TA and volumetric analysis may provide a way to evaluate the biologic aggressiveness of breast tumours and provide aid in decisions regarding therapeutic efficacy.

  20. Formation of vacancy clusters in tungsten crystals under hydrogen-rich condition

    International Nuclear Information System (INIS)

    Kato, Daiji; Iwakiri, Hirotomo; Morishita, Kazunori

    2011-01-01

    Di-vacancy formation assisted by hydrogen trapping is studied in terms of nucleation free-energies evaluated with density functional theory. Calculations give binding energies for single hydrogen atom as first- and second-nearest-neighbor of di-vacancies of 1.80 and 2.15 eV, respectively, which are significantly larger than that for mono-vacancies. At elevated atomic concentrations of interstitial hydrogen atoms, evaluated nucleation free-energies indicate that the hydrogen assisted di-vacancy formation becomes more favorable. It is suggested that the formation would be preceded by VH cluster formation.

  1. Formation of vacancy clusters in tungsten crystals under hydrogen-rich condition

    Energy Technology Data Exchange (ETDEWEB)

    Kato, Daiji, E-mail: kato.daiji@nifs.ac.jp [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, Gifu 509-5292 (Japan); Iwakiri, Hirotomo, E-mail: iwakiri@edu.u-ryukyu.ac.jp [University of the Ryukyus, Okinawa 903-0213 (Japan); Morishita, Kazunori, E-mail: morishita@iae.kyoto-u.ac.jp [Institute of Advanced Energy, Kyoto University, Kyoto 611-0011 (Japan)

    2011-10-01

    Di-vacancy formation assisted by hydrogen trapping is studied in terms of nucleation free-energies evaluated with density functional theory. Calculations give binding energies for single hydrogen atom as first- and second-nearest-neighbor of di-vacancies of 1.80 and 2.15 eV, respectively, which are significantly larger than that for mono-vacancies. At elevated atomic concentrations of interstitial hydrogen atoms, evaluated nucleation free-energies indicate that the hydrogen assisted di-vacancy formation becomes more favorable. It is suggested that the formation would be preceded by VH cluster formation.

  2. Comparing large covariance matrices under weak conditions on the dependence structure and its application to gene clustering.

    Science.gov (United States)

    Chang, Jinyuan; Zhou, Wen; Zhou, Wen-Xin; Wang, Lan

    2017-03-01

    Comparing large covariance matrices has important applications in modern genomics, where scientists are often interested in understanding whether relationships (e.g., dependencies or co-regulations) among a large number of genes vary between different biological states. We propose a computationally fast procedure for testing the equality of two large covariance matrices when the dimensions of the covariance matrices are much larger than the sample sizes. A distinguishing feature of the new procedure is that it imposes no structural assumptions on the unknown covariance matrices. Hence, the test is robust with respect to various complex dependence structures that frequently arise in genomics. We prove that the proposed procedure is asymptotically valid under weak moment conditions. As an interesting application, we derive a new gene clustering algorithm which shares the same nice property of avoiding restrictive structural assumptions for high-dimensional genomics data. Using an asthma gene expression dataset, we illustrate how the new test helps compare the covariance matrices of the genes across different gene sets/pathways between the disease group and the control group, and how the gene clustering algorithm provides new insights on the way gene clustering patterns differ between the two groups. The proposed methods have been implemented in an R-package HDtest and are available on CRAN. © 2016, The International Biometric Society.

  3. A pocket-sized luminance meter.

    NARCIS (Netherlands)

    Schreuder, D.A.

    1964-01-01

    In many case the light technician will feel the want of assessing the luminance of certain surfaces within his field of view in a quick and convenient manner. The measurement need not be very accurate, but it should be carried out with an apparatus so small that it can easily be taken along

  4. Optical system for a universal luminance meter

    NARCIS (Netherlands)

    Schreuder, D.A.

    1965-01-01

    There is a need for luminance meters in various fields of photometry having these characteristics: a- objective method of measurements. b. variable shape and size of measurement area. c- absence of parallax during aiming operations. d- Possibility of observing the part of the field of view to be

  5. Liquid-liquid phase separation and cluster formation at deposition of metals under inhomogeneous magnetic field

    Science.gov (United States)

    Gorobets, O. Yu; Gorobets, Yu I.; Rospotniuk, V. P.; Grebinaha, V. I.; Kyba, A. A.

    2017-10-01

    The formation and dynamic of expansion and deformation of the liquid-liquid interface of an electrolyte at deposition of metals at the surface of the magnetized steel ball is considered in this paper. The electrochemical processes were investigated in an external magnetic field directed at an arbitrary angle to the force of gravity. These processes are accompanied by the formation of effectively paramagnetic clusters of electrochemical products - magnions. Tyndall effect was used for detection of the presence of magnions near the magnetized steel electrode in a solution. The shape of the interface separating the regions with different concentration of magnions, i.e. different magnetic susceptibilities, was described theoretically based on the equation of hydrostatic equilibrium which takes into account magnetic, hydrostatic and osmotic pressures.

  6. The Polar Cusp Observed by Cluster Under Constant Imf-Bz Southward

    Science.gov (United States)

    Escoubet, C. P.; Berchem, J.; Pitout, F.; Trattner, K. J.; Richard, R. L.; Taylor, M. G.; Soucek, J.; Grison, B.; Laakso, H. E.; Masson, A.; Dunlop, M. W.; Dandouras, I. S.; Reme, H.; Fazakerley, A. N.; Daly, P. W.

    2011-12-01

    The Earth's magnetic field is influenced by the interplanetary magnetic field (IMF), specially at the magnetopause where both magnetic fields enter in direct contact and magnetic reconnection can be initiated. In the polar regions, the polar cusp that extends from the magnetopause down to the ionosphere is also directly influenced. The reconnection not only allow ions and electrons from the solar wind to enter the polar cusp but also give an impulse to the magnetic field lines threading the polar cusp through the reconnection electric field. A dispersion in energy of the ions is subsequently produced by the motion of field lines and the time-of-flight effect on down-going ions. If reconnection is continuous and operates at constant rate, the ion dispersion is smooth and continuous. On the other hand if the reconnection rate varies, we expect interruption in the dispersion forming energy steps or staircase. Similarly, multiple entries near the magnetopause could also produce steps at low or mid-altitude when a spacecraft is crossing subsequently the field lines originating from these multiple sources. Cluster with four spacecraft following each other in the mid-altitude cusp can be used to distinguish between these "temporal" and "spatial" effects. We will show two Cluster cusp crossings where the spacecraft were separated by a few minutes. The energy dispersions observed in the first crossing were the same during the few minutes that separated the spacecraft. In the second crossing, two ion dispersions were observed on the first spacecraft and only one of the following spacecraft, about 10 min later. The detailed analysis indicates that these steps result from spatial structures.

  7. Effects of improved sanitation on diarrheal reduction for children under five in Idiofa, DR Congo: a cluster randomized trial.

    Science.gov (United States)

    Cha, Seungman; Lee, JaeEun; Seo, DongSik; Park, Byoung Mann; Mansiangi, Paul; Bernard, Kabore; Mulakub-Yazho, Guy Jerome Nkay; Famasulu, Honore Minka

    2017-09-19

    The lack of safe water and sanitation contributes to the rampancy of diarrhea in many developing countries. This study describes the design of a cluster-randomized trial in Idiofa, the Democratic Republic of the Congo, seeking evidence of the impact of improved sanitation on diarrhea for children under four. Of the 276 quartiers, 18 quartiers were randomly allocated to the intervention or control arm. Seven hundred and-twenty households were sampled and the youngest under-four child in each household was registered for this study. The primary endpoint of the study is diarrheal incidence, prevalence and duration in children under five. Material subsidies will be provided only to the households who complete pit digging plus superstructure and roof construction, regardless of their income level. This study employs a Sanitation Calendar so that the mother of each household can record the diarrheal episodes of her under-four child on a daily basis. The diary enables examination of the effect of the sanitation intervention on diarrhea duration and also resolves the limitation of the small number of clusters in the trial. In addition, the project will be monitored through the 'Sanitation Map', on which all households in the study area, including both the control and intervention arms, are registered. To avoid information bias or courtesy bias, photos will be taken of the latrine during the household visit, and a supervisor will determine well-equipped latrine uptake based on the photos. This reduces the possibility of recall bias and under- or over-estimation of diarrhea, which was the main limitation of previous studies. The study was approved by the Institutional Review Board of the School of Public Health, Kinshasa University (ESP/CE/040/15; April 13, 2015) and registered as an International Standard Randomized Controlled Trial (ISRCTN: 10,419,317) on March 13, 2015.

  8. Ecology and biology of luminous bacteria in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    Extensive studies on occurrence, distribution and species composition of luminous bacteria in the Arabian Sea were carried out from various habitats. Luminous bacterial population was by far the highest in the environs of the Arabian Sea...

  9. Cluster Analysis of Monthly Precipitation over the Western Maritime Continent under Climate Change

    Directory of Open Access Journals (Sweden)

    Saurabh K Singh

    2017-11-01

    Full Text Available Changes in climate because of global warming during the 20th and 21st centuries have a direct impact on the hydrological cycle as driven by precipitation. However, studying precipitation over the Western Maritime Continent (WMC is a great challenge, as the WMC has a complex topography and weather system. Understanding changes in precipitation patterns and their groupings is an important aspect of planning mitigation measures to minimize flood and drought risk as well as of understanding the redistribution of precipitation arising from climate change. This paper employs Ward’s hierarchical clustering on regional climate model (RCM-simulated monthly precipitation gridded data over 42 approximately evenly distributed grid stations from the years 2030 to 2060. The aim was to investigate spatial and temporal groupings over the four major landmasses in the WMC and to compare these with historical precipitation groupings. The results showed that the four large-scale islands of Java, Sumatra, Peninsular Malaysia and Borneo would experience a significant spatial redistribution of precipitation over the years 2030 to 2060, as compared to historical patterns from 1980 to 2005. The spatial groups were also compared for two future forcing scenarios, representative concentration pathways (RCPs 4.5 and 8.5, and different groupings over the Borneo region were observed.

  10. Structural, Functional, and Clinical Characterization of a Novel PTPN11 Mutation Cluster Underlying Noonan Syndrome.

    Science.gov (United States)

    Pannone, Luca; Bocchinfuso, Gianfranco; Flex, Elisabetta; Rossi, Cesare; Baldassarre, Giuseppina; Lissewski, Christina; Pantaleoni, Francesca; Consoli, Federica; Lepri, Francesca; Magliozzi, Monia; Anselmi, Massimiliano; Delle Vigne, Silvia; Sorge, Giovanni; Karaer, Kadri; Cuturilo, Goran; Sartorio, Alessandro; Tinschert, Sigrid; Accadia, Maria; Digilio, Maria C; Zampino, Giuseppe; De Luca, Alessandro; Cavé, Hélène; Zenker, Martin; Gelb, Bruce D; Dallapiccola, Bruno; Stella, Lorenzo; Ferrero, Giovanni B; Martinelli, Simone; Tartaglia, Marco

    2017-04-01

    Germline mutations in PTPN11, the gene encoding the Src-homology 2 (SH2) domain-containing protein tyrosine phosphatase (SHP2), cause Noonan syndrome (NS), a relatively common, clinically variable, multisystem disorder. Here, we report on the identification of five different PTPN11 missense changes affecting residues Leu 261 , Leu 262 , and Arg 265 in 16 unrelated individuals with clinical diagnosis of NS or with features suggestive for this disorder, specifying a novel disease-causing mutation cluster. Expression of the mutant proteins in HEK293T cells documented their activating role on MAPK signaling. Structural data predicted a gain-of-function role of substitutions at residues Leu 262 and Arg 265 exerted by disruption of the N-SH2/PTP autoinhibitory interaction. Molecular dynamics simulations suggested a more complex behavior for changes affecting Leu 261 , with possible impact on SHP2's catalytic activity/selectivity and proper interaction of the PTP domain with the regulatory SH2 domains. Consistent with that, biochemical data indicated that substitutions at codons 262 and 265 increased the catalytic activity of the phosphatase, while those affecting codon 261 were only moderately activating but impacted substrate specificity. Remarkably, these mutations underlie a relatively mild form of NS characterized by low prevalence of cardiac defects, short stature, and cognitive and behavioral issues, as well as less evident typical facial features. © 2017 WILEY PERIODICALS, INC.

  11. The Formation of Primordial Luminous Objects

    International Nuclear Information System (INIS)

    Ripamonti, Emanuele; Kapteyn Astron. Inst., Groningen; Abel, Tom; KIPAC, Menlo Park

    2005-01-01

    The scientific belief that the universe evolves in time is one of the legacies of the theory of the Big Bang. The concept that the universe has an history started to attract the interest of cosmologists soon after the first formulation of the theory: already Gamow (1948; 1949) investigated how and when galaxies could have been formed in the context of the expanding Universe. However, the specific topic of the formation (and of the fate) of the first objects dates to two decades later, when no objects with metallicities as low as those predicted by primordial nucleosynthesis (Z ∼ -10 ∼ 10 -8 Z # circle d ot#) were found. Such concerns were addressed in two seminal papers by Peebles and Dicke (1968; hereafter PD68) and by Doroshkevich, Zel'Dovich and Novikov (1967; hereafter DZN67), introducing the idea that some objects could have formed before the stars we presently observe. (1) Both PD68 and DZN67 suggest a mass of ∼ 10 5 M # circle d ot# for the first generation of bound systems, based on the considerations on the cosmological Jeans length (Gamow 1948; Peebles 1965) and the possible shape of the power spectrum. (2) They point out the role of thermal instabilities in the formation of the proto-galactic bound object, and of the cooling of the gas inside it; in particular, PD68 introduces H 2 cooling and chemistry in the calculations about the contraction of the gas. (3) Even if they do not specifically address the occurrence of fragmentation, these papers make two very different assumptions: PD68 assumes that the gas will fragment into ''normal'' stars to form globular clusters, while DZN67 assumes that fragmentation does not occur, and that a single ''super-star'' forms. (4) Finally, some feedback effects as considered (e.g. Peebles and Dicke considered the effects of supernovae). Today most of the research focuses on the issues when fragmentation may occur, what objects are formed and how they influence subsequent structure formation. In these notes we will

  12. ["Glare vision". I. Physiological principles of vision change with increased test field luminance].

    Science.gov (United States)

    Hauser, B; Ochsner, H; Zrenner, E

    1992-02-01

    Clinical tests of visual acuity are an important measure of visual function. However visual acuity is usually determined only in narrow range of luminance levels between 160 and 320 cd/m2; therefore losses of visual acuity in other ranges of light intensity can not be detected. In a distance of 80 cm from the patients eyes, Landolt rings of varying sizes were presented on a small test field whose light intensity can be varied between 0.1 and 30,000 cd/m2. Thereby an acuity-luminance-function can be obtained. We studied such functions under different conditions of exposure time both with constant and with increasing luminance of the test field. We found that persons with normal vision can increase their visual acuity with increasing test field luminance up to a range of 5000 cd/m2. The maximum values of visual acuity under optimal lightening conditions lie (varying with age) between 2.2 and 0.9. Under pathological conditions visual acuity falls at high luminances accompanied by sensations of glare. Tests of glare sensitivity as a function of exposure time showed 4 sec to be a critical time of exposure since after 4 sec normal persons just reach their maximum visual acuity at high luminances. The underlying physiological mechanisms lead us to suppose that patients with neuronal light adaptation disturbances display a greater visual loss as a result of decreased time of exposure than those with disturbances in the ocular media. Visual acuity as well as the capacity to increase the patients visual acuity under optimal conditions of lighting were both found to be strongly age-dependent.(ABSTRACT TRUNCATED AT 250 WORDS)

  13. White LEDs with limit luminous efficacy

    Energy Technology Data Exchange (ETDEWEB)

    Lisitsyn, V. M.; Stepanov, S. A., E-mail: stepanovsa@tpu.ru; Yangyang, Ju [National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Lukash, V. S. [JSC Research Institute of Semiconductor Devices, 99a Krasnoarmeyskaja St., Tomsk, 634050 (Russian Federation)

    2016-01-15

    In most promising widespread gallium nitride based LEDs emission is generated in the blue spectral region with a maximum at about 450 nm which is converted to visible light with the desired spectrum by means of phosphor. The thermal energy in the conversion is determined by the difference in the energies of excitation and emission quanta and the phosphor quantum yield. Heat losses manifest themselves as decrease in the luminous efficacy. LED heating significantly reduces its efficiency and life. In addition, while heating, the emission generation output and the efficiency of the emission conversion decrease. Therefore, the reduction of the energy losses caused by heating is crucial for LED development. In this paper, heat losses in phosphor-converted LEDs (hereinafter chips) during spectrum conversion are estimated. The limit values of the luminous efficacy for white LEDs are evaluated.

  14. Small interstitial clusters as opposite defect recombinators in decomposing solid solutions under irradiation

    International Nuclear Information System (INIS)

    Orlov, A.N.; Trushin, Yu.V.

    1988-01-01

    An attempt was made to make allowance for the role of binary and ternary interstitials in the kinetics of radiation point defects both in the presence and in the absence of coherent preseparation. It is shown that in solid solutions, decomposing under irradiation, recombination with binary and ternary interstitials proceeds more quickly than directly, and this difference is more pronounced (from 2 up to 20 time growth) due to defect flow for preseparation at the stage of coherent preseparation formation

  15. Adaptações fisiológicas e anatômicas de Melissa officinalis L. (Lamiaceae cultivadas sob malhas termorrefletoras em diferentes intensidades luminosas Physiological and morphological adaptations of Melissa officinalis L. (Lamiaceae cultivated under thermo-reflector shading nets at different luminous intensities

    Directory of Open Access Journals (Sweden)

    R.S. Brant

    2011-01-01

    Full Text Available Objetivou-se, com a realização da pesquisa, avaliar modificações fisiológicas e anatômicas em plantas de melissa, cultivadas sob malhas termorrefletoras (Aluminet®, em diferentes níveis de sombreamento, visando conhecer a plasticidade fenotípica em resposta de adaptação a diferentes quantidades de luz. Os tratamentos foram caracterizados por plantas submetidas a pleno sol e a 20 e 60% de intensidade luminosa, e arranjados conforme o delineamento inteiramente casualizado (DIC. As quantificações de clorofila foram feitas em quatro repetições, as medições das epidermes e parênquimas foram repetidas 15 vezes e utilizou-se 10 repetições para as avaliações das características de cloroplastos e grãos de amido destes. Plantas submetidas a 20% de intensidade luminosa apresentaram maior quantidade de clorofila a e, portanto, maior razão clorofila a/b. Comparativamente, as folhas de melissa a pleno sol e a 60% de luz apresentaram células da epiderme adaxial mais espessas, mas as células da epiderme abaxial mostraram características encontradas em folhas de sombra, ou seja, mais finas. Quanto maior a intensidade luminosa, maior o número de cloroplastos, porém, a pleno sol mostraram-se mais finos e com menor área. Os grãos de amido de plantas cultivadas sob ambientes sombreados tiveram maior área e ocuparam maior parte nos cloroplastos de plantas a 60% de intensidade luminosa. Assim, plantas de melissa, quando submetidas ao sombreamento, tiveram plasticidade fenotípica.The aim of this study was to evaluate physiological and anatomical modifications in lemon balm plants, cultivated under thermo-reflector nets (Aluminet® at different levels of shading, in order to understand the phenotypic plasticity in adaptation response to different light quantities. The treatments were characterized by plants subjected to full sun and 20 and 60% of luminous intensity, and arranged in completely randomized design (CRD. The quantifications

  16. Luminance-based specular gloss characterization

    OpenAIRE

    Leloup, Frédéric; Pointer, Michael R.; Dutré, Philip; Hanselaer, Peter

    2011-01-01

    Gloss is a feature of visual appearance that arises from the directionally selective reflection of light incident on a surface. Especially when a distinct reflected image is perceptible, the luminance distribution of the illumination scene above the sample can strongly influence the gloss perception. For this reason, industrial glossmeters do not provide a satisfactory gloss estimation of high-gloss surfaces. In this study, the influence of the conditions of illumination on specular ...

  17. Luminance-based specular gloss characterization.

    Science.gov (United States)

    Leloup, Frédéric B; Pointer, Michael R; Dutré, Philip; Hanselaer, Peter

    2011-06-01

    Gloss is a feature of visual appearance that arises from the directionally selective reflection of light incident on a surface. Especially when a distinct reflected image is perceptible, the luminance distribution of the illumination scene above the sample can strongly influence the gloss perception. For this reason, industrial glossmeters do not provide a satisfactory gloss estimation of high-gloss surfaces. In this study, the influence of the conditions of illumination on specular gloss perception was examined through a magnitude estimation experiment in which 10 observers took part. A light booth with two light sources was utilized: the mirror image of only one source being visible in reflection by the observer. The luminance of both the reflected image and the adjacent sample surface could be independently varied by separate adjustment of the intensity of the two light sources. A psychophysical scaling function was derived, relating the visual gloss estimations to the measured luminance of both the reflected image and the off-specular sample background. The generalization error of the model was estimated through a validation experiment performed by 10 other observers. In result, a metric including both surface and illumination properties is provided. Based on this metric, improved gloss evaluation methods and instruments could be developed.

  18. The Research Search For The Least Beneficial Overcast Sky And Progress In Defining Its Luminance Gradation Function

    Directory of Open Access Journals (Sweden)

    Kittler R.

    2014-09-01

    Full Text Available Recently illuminance levels under ISO/CIE homogeneous standard sky types were characterised in their relative terms after ISO/CIE (2004, 2003 standardised as normalised by the luminance in the zenith. Sky luminance and horizontal illuminance based on the gradation and scattering indicatrix functions, including the extreme overcast cases frequently encountered in nature, were recently determined in absolute physical units of luminance in kilocandles per meter square and of illuminance in kilolux. The historical search to find energy and visibility critical sky luminance distributions shows a progression of steps in studying the worst or critical overcast situations. That progression has enabled the determination and evaluation of interior illuminance for comparison of the merits of dual daylighting and artificial lighting under established criteria for comfortable visibility.

  19. Measurement of luminance noise and chromaticity noise of LCDs with a colorimeter and a color camera

    Science.gov (United States)

    Roehrig, H.; Dallas, W. J.; Krupinski, E. A.; Redford, Gary R.

    2007-09-01

    This communication focuses on physical evaluation of image quality of displays for applications in medical imaging. In particular we were interested in luminance noise as well as chromaticity noise of LCDs. Luminance noise has been encountered in the study of monochrome LCDs for some time, but chromaticity noise is a new type of noise which has been encountered first when monochrome and color LCDs were compared in an ROC study. In this present study one color and one monochrome 3 M-pixel LCDs were studied. Both were DICOM calibrated with equal dynamic range. We used a Konica Minolta Chroma Meter CS-200 as well as a Foveon color camera to estimate luminance and chrominance variations of the displays. We also used a simulation experiment to estimate luminance noise. The measurements with the colorimeter were consistent. The measurements with the Foveon color camera were very preliminary as color cameras had never been used for image quality measurements. However they were extremely promising. The measurements with the colorimeter and the simulation results showed that the luminance and chromaticity noise of the color LCD were larger than that of the monochrome LCD. Under the condition that an adequate calibration method and image QA/QC program for color displays are available, we expect color LCDs may be ready for radiology in very near future.

  20. THE PANCHROMATIC HUBBLE ANDROMEDA TREASURY. III. MEASURING AGES AND MASSES OF PARTIALLY RESOLVED STELLAR CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Beerman, Lori C.; Johnson, L. Clifton; Fouesneau, Morgan; Dalcanton, Julianne J.; Weisz, Daniel R.; Williams, Ben F. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Seth, Anil C. [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Bianchi, Luciana C. [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Dolphin, Andrew E. [Raytheon Company, 1151 East Hermans Road, Tucson, AZ 85756 (United States); Gouliermis, Dimitrios A. [Zentrum fuer Astronomie, Institut fuer Theoretische Astrophysik, Universitaet Heidelberg, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Kalirai, Jason S. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Larsen, Soren S. [Department of Astrophysics, IMAPP, Radboud University Nijmegen, P.O. Box 9010, NL-6500 GL Nijmegen (Netherlands); Melbourne, Jason L. [Caltech Optical Observatories, Division of Physics, Mathematics and Astronomy, Mail Stop 301-17, California Institute of Technology, Pasadena, CA 91125 (United States); Rix, Hans-Walter [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Skillman, Evan D., E-mail: beermalc@astro.washington.edu [Department of Astronomy, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States)

    2012-12-01

    The apparent age and mass of a stellar cluster can be strongly affected by stochastic sampling of the stellar initial mass function (IMF), when inferred from the integrated color of low-mass clusters ({approx}<10{sup 4} M {sub Sun }). We use simulated star clusters to show that these effects are minimized when the brightest, rapidly evolving stars in a cluster can be resolved, and the light of the fainter, more numerous unresolved stars can be analyzed separately. When comparing the light from the less luminous cluster members to models of unresolved light, more accurate age estimates can be obtained than when analyzing the integrated light from the entire cluster under the assumption that the IMF is fully populated. We show the success of this technique first using simulated clusters, and then with a stellar cluster in M31. This method represents one way of accounting for the discrete, stochastic sampling of the stellar IMF in less massive clusters and can be leveraged in studies of clusters throughout the Local Group and other nearby galaxies.

  1. Influence of Spatial and Chromatic Noise on Luminance Discrimination.

    Science.gov (United States)

    Miquilini, Leticia; Walker, Natalie A; Odigie, Erika A; Guimarães, Diego Leite; Salomão, Railson Cruz; Lacerda, Eliza Maria Costa Brito; Cortes, Maria Izabel Tentes; de Lima Silveira, Luiz Carlos; Fitzgerald, Malinda E C; Ventura, Dora Fix; Souza, Givago Silva

    2017-12-05

    Pseudoisochromatic figures are designed to base discrimination of a chromatic target from a background solely on the chromatic differences. This is accomplished by the introduction of luminance and spatial noise thereby eliminating these two dimensions as cues. The inverse rationale could also be applied to luminance discrimination, if spatial and chromatic noise are used to mask those cues. In this current study estimate of luminance contrast thresholds were conducted using a novel stimulus, based on the use of chromatic and spatial noise to mask the use of these cues in a luminance discrimination task. This was accomplished by presenting stimuli composed of a mosaic of circles colored randomly. A Landolt-C target differed from the background only by the luminance. The luminance contrast thresholds were estimated for different chromatic noise saturation conditions and compared to luminance contrast thresholds estimated using the same target in a non-mosaic stimulus. Moreover, the influence of the chromatic content in the noise on the luminance contrast threshold was also investigated. Luminance contrast threshold was dependent on the chromaticity noise strength. It was 10-fold higher than thresholds estimated from non-mosaic stimulus, but they were independent of colour space location in which the noise was modulated. The present study introduces a new method to investigate luminance vision intended for both basic science and clinical applications.

  2. Relation between acid back-diffusion and luminal surface hydrophobicity in canine gastric mucosa: Effects of salicylate and prostaglandin

    International Nuclear Information System (INIS)

    Goddard, P.J.

    1989-01-01

    The stomach is thought to be protected from luminal acid by a gastric mucosal barrier that restricts the diffusion of acid into tissue. This study tested the hypothesis that the hydrophobic luminal surface of canine gastric mucosa incubated in Ussing chambers, impedes the back-diffusion of luminal acid into the tissue. Isolated sheets of mucosa were treated with cimetidine to inhibit spontaneous acid secretion, and incubated under conditions that prevented significant secretion of luminal bicarbonate. By measuring acid loss from the luminal compartment using the pH-stat technique, acid back-diffusion was continuously monitored; potential difference (PD) was measured as an index of tissue viability. Tissue luminal surface hydrophobicity was estimated by contact angle analysis at the end of each experiment. Addition of 16,16-dimethyl prostaglandin E 2 to the nutrient compartment enhanced luminal surface hydrophobicity, but did not reduce acid back-diffusion in tissues that maintained a constant PD. 10 mM salicylate at pH 4.00 in the luminal compartment reduced surface hydrophobicity, but this decrease did not occur if 1 ug/ml prostaglandin was present in the nutrient solution. Despite possessing relatively hydrophilic and relatively hydrophobic surface properties, respectively, acid back-diffusion in the absence of salicylate was not significantly different between these two groups. Neither group maintained a PD after incubation with salicylate. Lastly, radiolabeled salicylate was used to calculate the free (non-salicylate associated) acid loss in tissues incubated with salicylate and/or prostaglandin. No significant correlation was found between free acid back-diffusion and luminal surface hydrophobicity. These data do not support the hypothesis that acid back-diffusion in impeded by the hydrophobic surface presented by isolated canine gastric mucosa

  3. A new interpretation of luminous blue stars

    International Nuclear Information System (INIS)

    Stothers, R.

    1976-01-01

    A major revision of current theoretical ideas about the brightest blue stars must be made if Carson's new radiative opacities are adopted in stellar models. Unlike earlier opacities, the new opacities exhibit a large ''bump'' due to CNO ionization, which leads to very strong central condensation, convective instability, and pulsational instability in hot, diffuse stellar envelopes (typically those in which L/M>10 3 solar units). Despite a number of theoretical uncertainties, the new picture of the structure of very luminous stars is reasonably successful in accounting for a variety of previously unexplained observations. Thus, the new stellar models for the phase of core hydrogen burning predict large radii and rather cool effective temperatures (which are yet to be observationally confirmed) for O stars, and a spreading out of the main-sequence band in the H-R diagram toward luminous cool supergiants for masses higher than approx.20 M/sub sun/, beginning at M/sub v/=-4.5 and Sp=B1. They also predict slower surface rotations for O stars compared with B stars; and, in binary systems, slower apsidal motions, closer rotational-revolutional synchronism, and smaller orbital eccentricities. In massive X-ray binary systems, circular orbits and supergiant-like visual companions are expected to be quite common. Radial pulsations of the models have been calculated by employing linearized nonadiabatic pulsation theory. Long-period variability is predicted to exist for massive blue supergiants of luminosity class Ia. The new models for helium stars predict large radii and rather cool effective temperatures for Wolf-Rayet stars, as well as multimodal pulsational instability and, possibly, surface turbulence for these stars. Ultrashort-period variability, observed in many classes of hot luminous stars, may be due, in part, to high radial overtone pulsations (or, possibly, to nonradial pulsation or convective modes)

  4. Observations of Intermediate-mass Black Holes and Ultra-Luminous X-ray sources

    Science.gov (United States)

    Colbert, E. J. M.

    2003-12-01

    I will review various observations that suggest that intermediate-mass black holes (IMBHs) with masses ˜102-104 M⊙ exist in our Universe. I will also discuss some of the limitations of these observations. HST Observations of excess dark mass in globular cluster cores suggest IMBHs may be responsible, and some mass estimates from lensing experiments are nearly in the IMBH range. The intriguing Ultra-Luminous X-ray sources (ULXs, or IXOs) are off-nuclear X-ray point sources with X-ray luminosities LX ≳ 1039 erg s-1. ULXs are typically rare (1 in every 5 galaxies), and the nature of their ultra-luminous emission is currently debated. I will discuss the evidence for IMBHs in some ULXs, and briefly outline some phenomenology. Finally, I will discuss future observations that can be made to search for IMBHs.

  5. Carbon stars in lmc clusters revisited

    OpenAIRE

    Marigo, Paola; Girardi, Leo Alberto; Chiosi, Cesare

    1996-01-01

    Examining the available data for AGB stars in the Large Magellanic Cloud (LMC) clusters, we address the question about the mass interval of low- and intermediate-mass stars which eventually evolve into carbon stars (C stars) during the TP-AGB phase. We combine the data compiled by Frogel, Mould & Blanco (1990) - near infrared photometry and spectral classification for luminous AGB stars in clusters - with the ages for individual clusters derived from independent methods. The resulting distrib...

  6. Standard deviation of luminance distribution affects lightness and pupillary response.

    Science.gov (United States)

    Kanari, Kei; Kaneko, Hirohiko

    2014-12-01

    We examined whether the standard deviation (SD) of luminance distribution serves as information of illumination. We measured the lightness of a patch presented in the center of a scrambled-dot pattern while manipulating the SD of the luminance distribution. Results showed that lightness decreased as the SD of the surround stimulus increased. We also measured pupil diameter while viewing a similar stimulus. The pupil diameter decreased as the SD of luminance distribution of the stimuli increased. We confirmed that these results were not obtained because of the increase of the highest luminance in the stimulus. Furthermore, results of field measurements revealed a correlation between the SD of luminance distribution and illuminance in natural scenes. These results indicated that the visual system refers to the SD of the luminance distribution in the visual stimulus to estimate the scene illumination.

  7. Luminance cues constrain chromatic blur discrimination in natural scene stimuli.

    Science.gov (United States)

    Sharman, Rebecca J; McGraw, Paul V; Peirce, Jonathan W

    2013-03-22

    Introducing blur into the color components of a natural scene has very little effect on its percept, whereas blur introduced into the luminance component is very noticeable. Here we quantify the dominance of luminance information in blur detection and examine a number of potential causes. We show that the interaction between chromatic and luminance information is not explained by reduced acuity or spatial resolution limitations for chromatic cues, the effective contrast of the luminance cue, or chromatic and achromatic statistical regularities in the images. Regardless of the quality of chromatic information, the visual system gives primacy to luminance signals when determining edge location. In natural viewing, luminance information appears to be specialized for detecting object boundaries while chromatic information may be used to determine surface properties.

  8. Data Clustering

    Science.gov (United States)

    Wagstaff, Kiri L.

    2012-03-01

    On obtaining a new data set, the researcher is immediately faced with the challenge of obtaining a high-level understanding from the observations. What does a typical item look like? What are the dominant trends? How many distinct groups are included in the data set, and how is each one characterized? Which observable values are common, and which rarely occur? Which items stand out as anomalies or outliers from the rest of the data? This challenge is exacerbated by the steady growth in data set size [11] as new instruments push into new frontiers of parameter space, via improvements in temporal, spatial, and spectral resolution, or by the desire to "fuse" observations from different modalities and instruments into a larger-picture understanding of the same underlying phenomenon. Data clustering algorithms provide a variety of solutions for this task. They can generate summaries, locate outliers, compress data, identify dense or sparse regions of feature space, and build data models. It is useful to note up front that "clusters" in this context refer to groups of items within some descriptive feature space, not (necessarily) to "galaxy clusters" which are dense regions in physical space. The goal of this chapter is to survey a variety of data clustering methods, with an eye toward their applicability to astronomical data analysis. In addition to improving the individual researcher’s understanding of a given data set, clustering has led directly to scientific advances, such as the discovery of new subclasses of stars [14] and gamma-ray bursts (GRBs) [38]. All clustering algorithms seek to identify groups within a data set that reflect some observed, quantifiable structure. Clustering is traditionally an unsupervised approach to data analysis, in the sense that it operates without any direct guidance about which items should be assigned to which clusters. There has been a recent trend in the clustering literature toward supporting semisupervised or constrained

  9. Coma cluster of galaxies

    Science.gov (United States)

    1999-01-01

    Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

  10. Reduced-dimension power allocation over clustered channels in cognitive radios system under co-channel interference

    KAUST Repository

    Ben Ghorbel, Mahdi; Guenach, Mamoun; Alouini, Mohamed-Slim

    2014-01-01

    and secondary systems. Instead of optimizing the powers over all sub-carriers, the sub-carriers are grouped into clusters of sub-carriers, where the power of each sub-carrier is directly related to the power of the correspondent cluster. The power optimization

  11. The Weak Lensing Masses of Filaments between Luminous Red Galaxies

    Science.gov (United States)

    Epps, Seth D.; Hudson, Michael J.

    2017-07-01

    In the standard model of non-linear structure formation, a cosmic web of dark-matter-dominated filaments connects dark matter haloes. In this paper, we stack the weak lensing signal of an ensemble of filaments between groups and clusters of galaxies. Specifically, we detect the weak lensing signal, using CFHTLenS galaxy ellipticities, from stacked filaments between Sloan Digital Sky Survey (SDSS)-III/Baryon Oscillation Spectroscopic Survey luminous red galaxies (LRGs). As a control, we compare the physical LRG pairs with projected LRG pairs that are more widely separated in redshift space. We detect the excess filament mass density in the projected pairs at the 5σ level, finding a mass of (1.6 ± 0.3) × 1013 M⊙ for a stacked filament region 7.1 h-1 Mpc long and 2.5 h-1 Mpc wide. This filament signal is compared with a model based on the three-point galaxy-galaxy-convergence correlation function, as developed in Clampitt et al., yielding reasonable agreement.

  12. The HR diagram for luminous stars in nearby galaxies

    International Nuclear Information System (INIS)

    Humphreys, R.M.

    1978-01-01

    Due to the extreme faintness of stars in other galaxies it is only possible to sample the brightest stars in the nearest galaxies. The observations must then be compared with comparable data for the brightest stars, the supergiants and O-type stars, in the Milky Way. The data for the luminous stars are most complete for the Milky Way and the Large Magellanic Cloud. The luminosities for the stars in our Galaxy are based on their membership in associations and clusters, and consequently are representative of Population I within approximately 3kpc of the Sun. The data for the stars in the LMC with spectral types O to G8 come from published observations, and the M supergiants are from the author's recent observations of red stars in the LMC. This is the first time that the M supergiants have been included in an HR diagram of the Large Cloud. The presence of the red stars is important for any discussion of the evolution of the massive stars. (Auth.)

  13. Chromatic blur perception in the presence of luminance contrast.

    Science.gov (United States)

    Jennings, Ben J; Kingdom, Frederick A A

    2017-06-01

    Hel-Or showed that blurring the chromatic but not the luminance layer of an image of a natural scene failed to elicit any impression of blur. Subsequent studies have suggested that this effect is due either to chromatic blur being masked by spatially contiguous luminance edges in the scene (Journal of Vision 13 (2013) 14), or to a relatively compressed transducer function for chromatic blur (Journal of Vision 15 (2015) 6). To test between the two explanations we conducted experiments using as stimuli both images of natural scenes as well as simple edges. First, we found that in color-and-luminance images of natural scenes more chromatic blur was needed to perceptually match a given level of blur in an isoluminant, i.e. colour-only scene. However, when the luminance layer in the scene was rotated relative to the chromatic layer, thus removing the colour-luminance edge correlations, the matched blur levels were near equal. Both results are consistent with Sharman et al.'s explanation. Second, when observers matched the blurs of luminance-only with isoluminant scenes, the matched blurs were equal, against Kingdom et al.'s prediction. Third, we measured the perceived blur in a square-wave as a function of (i) contrast (ii) number of luminance edges and (iii) the relative spatial phase between the colour and luminance edges. We found that the perceived chromatic blur was dependent on both relative phase and the number of luminance edges, or dependent on the luminance contrast if only a single edge is present. We conclude that this Hel-Or effect is largely due to masking of chromatic blur by spatially contiguous luminance edges. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Clustering of near clusters versus cluster compactness

    International Nuclear Information System (INIS)

    Yu Gao; Yipeng Jing

    1989-01-01

    The clustering properties of near Zwicky clusters are studied by using the two-point angular correlation function. The angular correlation functions for compact and medium compact clusters, for open clusters, and for all near Zwicky clusters are estimated. The results show much stronger clustering for compact and medium compact clusters than for open clusters, and that open clusters have nearly the same clustering strength as galaxies. A detailed study of the compactness-dependence of correlation function strength is worth investigating. (author)

  15. Galaxy masses in large surveys: Connecting luminous and dark matter with weak lensing and kinematics

    Science.gov (United States)

    Reyes, Reinabelle

    2011-01-01

    Galaxy masses are difficult to determine because light traces stars and gas in a non-trivial way, and does not trace dark matter, which extends well beyond the luminous regions of galaxies. In this thesis, I use the most direct probes of dark matter available---weak gravitational lensing and galaxy kinematics---to trace the total mass in galaxies (and galaxy clusters) in large surveys. In particular, I use the large, homogeneous dataset from the Sloan Digital Sky Survey (SDSS), which provides spectroscopic redshifts for a large sample of galaxies at z ≲ 0.2 and imaging data to a depth of r < 22. By combining complementary probes, I am able to obtain robust observational constraints that cannot be obtained from any single technique alone. First, I use weak lensing of galaxy clusters to derive an optimal optical tracer of cluster mass, which was found to be a combination of cluster richness and the luminosity of the brightest cluster galaxy. Next, I combine weak lensing of luminous red galaxies with redshift distortions and clustering measurements to derive a robust probe of gravity on cosmological scales. Finally, I combine weak lensing with the kinematics of disk galaxies to constrain the total mass profile over several orders of magnitude. I derive a minimal-scatter relation between disk velocity and stellar mass (also known as the Tully-Fisher relation) that can be used, by construction, on a similarly-selected lens sample. Then, I combine this relation with halo mass measurements from weak lensing to place constraints on the ratio of the optical to virial velocities, as well as the ratio of halo to stellar masses, both as a function of stellar mass. These results will serve as inputs to and constraints on disk galaxy formation models, which will be explored in future work.

  16. THE MOST LUMINOUS GALAXIES DISCOVERED BY WISE

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Chao-Wei; Eisenhardt, Peter R. M.; Stern, Daniel; Moustakas, Leonidas A. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109 (United States); Wu, Jingwen; Wright, Edward L. [Department of Physics and Astronomy, UCLA, Los Angeles, CA 90095-1547 (United States); Assef, Roberto J. [Núcleo de Astronomía de la Facultad deIngeniería, Universidad Diego Portales, Av. Ejército Libertador 441, Santiago (Chile); Blain, Andrew W. [Department of Physics and Astronomy, University of Leicester, 1 University Road, Leicester, LE1 7RH (United Kingdom); Bridge, Carrie R.; Sayers, Jack [Division of Physics, Math, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Benford, Dominic J.; Leisawitz, David T. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Cutri, Roc M.; Masci, Frank J.; Yan, Lin [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Griffith, Roger L. [Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Jarrett, Thomas H. [Astronomy Department, University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Lonsdale, Carol J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Petty, Sara M. [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Stanford, S. Adam, E-mail: Chao-Wei.Tsai@jpl.nasa.gov [Department of Physics, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); and others

    2015-06-01

    We present 20 Wide-field Infrared Survey Explorer (WISE)-selected galaxies with bolometric luminosities L{sub bol} > 10{sup 14} L{sub ☉}, including five with infrared luminosities L{sub IR} ≡ L{sub (rest} {sub 8–1000} {sub μm)} > 10{sup 14} L{sub ☉}. These “extremely luminous infrared galaxies,” or ELIRGs, were discovered using the “W1W2-dropout” selection criteria which requires marginal or non-detections at 3.4 and 4.6 μm (W1 and W2, respectively) but strong detections at 12 and 22 μm in the WISE survey. Their spectral energy distributions are dominated by emission at rest-frame 4–10 μm, suggesting that hot dust with T{sub d} ∼ 450 K is responsible for the high luminosities. These galaxies are likely powered by highly obscured active galactic nuclei (AGNs), and there is no evidence suggesting these systems are beamed or lensed. We compare this WISE-selected sample with 116 optically selected quasars that reach the same L{sub bol} level, corresponding to the most luminous unobscured quasars in the literature. We find that the rest-frame 5.8 and 7.8 μm luminosities of the WISE-selected ELIRGs can be 30%–80% higher than that of the unobscured quasars. The existence of AGNs with L{sub bol} > 10{sup 14} L{sub ☉} at z > 3 suggests that these supermassive black holes are born with large mass, or have very rapid mass assembly. For black hole seed masses ∼10{sup 3} M{sub ☉}, either sustained super-Eddington accretion is needed, or the radiative efficiency must be <15%, implying a black hole with slow spin, possibly due to chaotic accretion.

  17. Contribution of a luminance-dependent S-cone mechanism to non-assimilative color spreading in the watercolor configuration.

    Science.gov (United States)

    Kimura, Eiji; Kuroki, Mikako

    2014-01-01

    In the watercolor configuration composed of wavy double contours, both assimilative and non-assimilative color spreading have been demonstrated depending on the luminance conditions of the inner and outer contours (IC and OC, respectively). This study investigated how the induced color in the watercolor configuration was modulated by combinations of the IC and the OC color, particularly addressing non-assimilative color spreading. In two experiments, the IC color was fixed to a certain color and combined with various colors selected from a hue circle centered at the background white color. Color spreading was quantified with a chromatic cancelation technique. Results showed that both the magnitude and the apparent hue of the color spreading were largely changed with the luminance condition. When the IC contrast (Weber contrast of the IC to the background luminance) was smaller in size than the OC contrast (higher IC luminance condition), the color spreading was assimilative. When the luminance condition was reversed and the IC contrast was greater than the OC contrast (lower IC luminance condition), the color spreading was non-assimilative and yellowish. When the color spreading was analyzed in terms of cone-opponent excitations, the results were consistent with the interpretation that the color spreading is explainable by a combination of chromatic diffusion from the IC and chromatically opponent induction from the OC. The color spreading in the higher IC luminance condition mainly reflected the chromatic diffusion by both (L-M) and S cone-opponent mechanisms. The non-assimilative color spreading in the lower IC luminance condition mostly reflected S-cone mediated opponent induction and the contribution of -S inducing mechanisms was differentially large. These findings provided several constraints on possible visual mechanisms underlying the watercolor effect.

  18. Contribution of a luminance-dependent S-cone mechanism to non-assimilative color spreading in the watercolor configuration

    Directory of Open Access Journals (Sweden)

    Eiji eKimura

    2014-12-01

    Full Text Available In the watercolor configuration composed of wavy double contours, both assimilative and non-assimilative color spreading have been demonstrated depending on the luminance conditions of the inner and outer contours (IC and OC, respectively. This study investigated how the induced color in the watercolor configuration was modulated by combinations of the IC and the OC color, particularly addressing non-assimilative color spreading. In two experiments, the IC color was fixed to a certain color and combined with various colors selected from a hue circle centered at the background white color. Color spreading was quantified with a chromatic cancellation technique. Results showed that both the magnitude and the apparent hue of the color spreading were largely changed with the luminance condition. When the IC contrast (Weber contrast of the IC to the background luminance was smaller in size than the OC contrast (higher IC luminance condition, the color spreading was assimilative. When the luminance condition was reversed and the IC contrast was greater than the OC contrast (lower IC luminance condition, the color spreading was non-assimilative and yellowish. When the color spreading was analyzed in terms of cone-opponent excitations, the results were consistent with the interpretation that the color spreading is explainable by a combination of chromatic diffusion from the IC and chromatically opponent induction from the OC. The color spreading in the higher IC luminance condition mainly reflected the chromatic diffusion by both (L–M and S cone-opponent mechanisms. The non-assimilative color spreading in the lower IC luminance condition mostly reflected S-cone mediated opponent induction and the contribution of -S inducing mechanisms was differentially large. These findings provided several constraints on possible visual mechanisms underlying the watercolor effect.

  19. Covariation of Color and Luminance Facilitate Object Individuation in Infancy

    Science.gov (United States)

    Woods, Rebecca J.; Wilcox, Teresa

    2010-01-01

    The ability to individuate objects is one of our most fundamental cognitive capacities. Recent research has revealed that when objects vary in color or luminance alone, infants fail to individuate those objects until 11.5 months. However, color and luminance frequently covary in the natural environment, thus providing a more salient and reliable…

  20. Luminous flux and colour maintenance investigation of integrated LED lamps

    DEFF Research Database (Denmark)

    Corell, Dennis Dan; Thorseth, Anders; Dam-Hansen, Carsten

    2014-01-01

    This article will present an investigation of the luminous flux and colour maintenance of white LED based retrofit lamps. The study includes 23 different types of integrated LED lamps, covering 18 directional and 5 non-directional. Luminous flux and colour data for operation up to 20000 h has been...

  1. A CANDIDATE FOR THE MOST LUMINOUS OB ASSOCIATION IN THE GALAXY

    International Nuclear Information System (INIS)

    Rahman, Mubdi; Matzner, Christopher; Moon, Dae-Sik

    2011-01-01

    The Milky Way harbors giant H II regions, which may be powered by star complexes more luminous than any known Galactic OB association. Being across the disk of the Galaxy, however, these brightest associations are severely extinguished and confused. We present a search for one such association toward the most luminous H II region in the recent catalog by Murray and Rahman, which, at ∼9.7 kpc, has a recombination rate of ∼7 x 10 51 s -1 . Prior searches have identified only small-scale clustering around the rim of this shell-like region, but the primary association has not previously been identified. We apply a near-infrared color selection and find an overdensity of point sources toward its southern central part. The colors and magnitudes of these excess sources are consistent with O- and early B-type stars at extinctions 0.96 K < 1.2, and they are sufficiently numerous (406 ± 102 after subtraction of field sources) to ionize the surrounding H II region, making this a candidate for the most luminous OB association in the Galaxy. We reject an alternate theory, in which the apparent excess is caused by localized extinction, as inconsistent with source demographics.

  2. Contributions of contour frequency, amplitude, and luminance to the watercolor effect estimated by conjoint measurement.

    Science.gov (United States)

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

    2014-04-10

    The watercolor effect is a long-range, assimilative, filling-in phenomenon induced by a pair of distant, wavy contours of different chromaticities. Here, we measured joint influences of the contour frequency and amplitude and the luminance of the interior contour on the strength of the effect. Contour pairs, each enclosing a circular region, were presented with two of the dimensions varying independently across trials (luminance/frequency, luminance/amplitude, frequency/amplitude) in a conjoint measurement paradigm (Luce & Tukey, 1964). In each trial, observers judged which of the stimuli evoked the strongest fill-in color. Control stimuli were identical except that the contours were intertwined and generated little filling-in. Perceptual scales were estimated by a maximum likelihood method (Ho, Landy, & Maloney, 2008). An additive model accounted for the joint contributions of any pair of dimensions. As shown previously using difference scaling (Devinck & Knoblauch, 2012), the strength increases with luminance of the interior contour. The strength of the phenomenon was nearly independent of the amplitude of modulation of the contour but increased with its frequency up to an asymptotic level. On average, the strength of the effect was similar along a given dimension regardless of the other dimension with which it was paired, demonstrating consistency of the underlying estimated perceptual scales.

  3. Modulation of visual cortical excitability by working memory: effect of luminance contrast of mental imagery

    Directory of Open Access Journals (Sweden)

    Zaira eCattaneo

    2011-02-01

    Full Text Available Although much is known about the impact of stimulus properties such as luminance contrast, spatial frequency and orientation on visually evoked neural activity, much less is known about how they modulate neural activity when they are properties of a mental image held in working memory (WM. Here we addressed this question by investigating how a parametric manipulation of an imagined stimulus attribute affects neuronal excitability in the early visual cortex. We manipulated luminance contrast, a stimulus property known to strongly affect the magnitude of neuronal responses in early visual areas. Luminance contrast modulated neuronal excitability, as assessed by the frequency of phosphenes induced by transcranial magnetic stimulation (TMS with the exact nature of this modulation depending on TMS intensity. These results point to a strong overlap in the neuronal processes underlying visual perception and mental imagery: not only does WM maintenance selectively engage neurons which are tuned to the maintained attribute (as has previously been shown, but the extent to which those neurons are activated depends on the luminance contrast (as is the case with visually-evoked responses. From a methodological viewpoint, these results suggest that assessment of visual cortical excitability using TMS is affected by the TMS intensity used to probe the neuronal population.

  4. Luminal Cells Are Favored as the Cell of Origin for Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Zhu A. Wang

    2014-09-01

    Full Text Available The identification of cell types of origin for cancer has important implications for tumor stratification and personalized treatment. For prostate cancer, the cell of origin has been intensively studied, but it has remained unclear whether basal or luminal epithelial cells, or both, represent cells of origin under physiological conditions in vivo. Here, we use a novel lineage-tracing strategy to assess the cell of origin in a diverse range of mouse models, including Nkx3.1+/−; Pten+/−, Pten+/−, Hi-Myc, and TRAMP mice, as well as a hormonal carcinogenesis model. Our results show that luminal cells are consistently the observed cell of origin for each model in situ; however, explanted basal cells from these mice can generate tumors in grafts. Consequently, we propose that luminal cells are favored as cells of origin in many contexts, whereas basal cells only give rise to tumors after differentiation into luminal cells.

  5. High luminous flux from single crystal phosphor-converted laser-based white lighting system

    KAUST Repository

    Cantore, Michael

    2015-12-14

    The efficiency droop of light emitting diodes (LEDs) with increasing current density limits the amount of light emitted per wafer area. Since low current densities are required for high efficiency operation, many LED die are needed for high power white light illumination systems. In contrast, the carrier density of laser diodes (LDs) clamps at threshold, so the efficiency of LDs does not droop above threshold and high efficiencies can be achieved at very high current densities. The use of a high power blue GaN-based LD coupled with a single crystal Ce-doped yttrium aluminum garnet (YAG:Ce) sample was investigated for white light illumination applications. Under CW operation, a single phosphor-converted LD (pc-LD) die produced a peak luminous efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD operating efficiency. These results show that a single pc-LD die is capable of emitting enough luminous flux for use in a high power white light illumination system.

  6. Under a nonadherent state, bone marrow mesenchymal stem cells can be efficiently induced into functional islet-like cell clusters to normalize hyperglycemia in mice: a control study.

    Science.gov (United States)

    Zhang, Yihua; Dou, Zhongying

    2014-05-08

    Bone marrow mesenchymal stem cells (BMSCs) possess low immunogenicity and immunosuppression as an allograft, can differentiate into insulin-producing cells (IPCs) by in vitro induction, and may be a valuable cell source to regenerate pancreatic islets. However, the very low differentiation efficiency of BMSCs towards IPCs under adherent induction has thus far hindered the clinical exploitation of these cells. The aim of this study is to explore a new way to efficiently induce BMSCs into IPCs and lay the groundwork for their clinical exploitation. In comparison with adherent induction, BMSCs of human first-trimester abortus (hfBMSCs) under a nonadherent state were induced towards IPCs in noncoated plastic dishes using a three-stage induction procedure developed by the authors. Induction effects were evaluated by statistics of the cell clustering rate of induced cells, and ultrastructural observation, dithizone staining, quantitative polymerase chain reaction and immunofluorescence assay, insulin and c-peptide release under glucose stimulus of cell clusters, as well as transplantation test of the cell clusters in diabetic model mice. With (6.175 ± 0.263) × 105 cells in 508.5 ± 24.5 cell clusters, (3.303 ± 0.331) × 105 single cells and (9.478 ± 0.208) × 105 total cell count on average, 65.08 ± 2.98% hfBMSCs differentiated into pancreatic islet-like cell clusters after nonadherent induction. With (3.993 ± 0.344) × 105 cells in 332.3 ± 41.6 cell clusters, (5.437 ± 0.434) × 105 single cells and (9.430 ± 0.340) × 105 total cell count on average, 42.37 ± 3.70% hfBMSCs differentiated into pancreatic islet-like cell clusters after adherent induction (P produced human insulin in recipients. Our studies demonstrate that nonadherent induction can greatly promote BMSCs to form pancreatic islet-like cell clusters, thereby improving the differentiation efficiency of BMSCs towards IPCs.

  7. Evaluation of primary immunization coverage of infants under universal immunization programme in an urban area of Bangalore city using cluster sampling and lot quality assurance sampling techniques

    Directory of Open Access Journals (Sweden)

    Punith K

    2008-01-01

    Full Text Available Research Question: Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? Objective: To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Study Design: Population-based cross-sectional study. Study Setting: Areas under Mathikere Urban Health Center. Study Subjects: Children aged 12 months to 23 months. Sample Size: 220 in cluster sampling, 76 in lot quality assurance sampling. Statistical Analysis: Percentages and Proportions, Chi square Test. Results: (1 Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2 Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area.

  8. Evaluation of primary immunization coverage of infants under universal immunization programme in an urban area of bangalore city using cluster sampling and lot quality assurance sampling techniques.

    Science.gov (United States)

    K, Punith; K, Lalitha; G, Suman; Bs, Pradeep; Kumar K, Jayanth

    2008-07-01

    Is LQAS technique better than cluster sampling technique in terms of resources to evaluate the immunization coverage in an urban area? To assess and compare the lot quality assurance sampling against cluster sampling in the evaluation of primary immunization coverage. Population-based cross-sectional study. Areas under Mathikere Urban Health Center. Children aged 12 months to 23 months. 220 in cluster sampling, 76 in lot quality assurance sampling. Percentages and Proportions, Chi square Test. (1) Using cluster sampling, the percentage of completely immunized, partially immunized and unimmunized children were 84.09%, 14.09% and 1.82%, respectively. With lot quality assurance sampling, it was 92.11%, 6.58% and 1.31%, respectively. (2) Immunization coverage levels as evaluated by cluster sampling technique were not statistically different from the coverage value as obtained by lot quality assurance sampling techniques. Considering the time and resources required, it was found that lot quality assurance sampling is a better technique in evaluating the primary immunization coverage in urban area.

  9. Densities, cellulases, alginate and pectin lyases of luminous and other heterotrophic bacteria associated with marine algae

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    Epiphytic luminous and non-luminous bacteria were determined quantitatively for eight intertidal algal species from rocky beaches of Goa and Lakshadweep coral reef lagoon. Luminous bacteria were present on all eight algal species and contributed 2...

  10. Regulatory role of tetR gene in a novel gene cluster of Acidovorax avenae subsp. avenae RS-1 under oxidative stress

    Directory of Open Access Journals (Sweden)

    He eLiu

    2014-10-01

    Full Text Available Acidovorax avenae subsp. avenae is the causal agent of bacterial brown stripe disease in rice. In this study, we characterized a novel horizontal transfer of a gene cluster, including tetR, on the chromosome of A. avenae subsp. avenae RS-1 by genome-wide analysis. TetR acted as a repressor in this gene cluster and the oxidative stress resistance was enhanced in tetR-deletion mutant strain. Electrophoretic mobility shift assay (EMSA demonstrated that TetR regulator bound directly to the promoter of this gene cluster. Consistently, the results of quantitative real-time PCR also showed alterations in expression of associated genes. Moreover, the proteins affected by TetR under oxidative stress were revealed by comparing proteomic profiles of wild-type and mutant strains via 1D SDS-PAGE and LC-MS/MS analyses. Taken together, our results demonstrated that tetR gene in this novel gene cluster contributed to cell survival under oxidative stress, and TetR protein played an important regulatory role in growth kinetics, biofilm-forming capability, SOD and catalase activity, and oxide detoxicating ability.

  11. Regulatory role of tetR gene in a novel gene cluster of Acidovorax avenae subsp. avenae RS-1 under oxidative stress.

    Science.gov (United States)

    Liu, He; Yang, Chun-Lan; Ge, Meng-Yu; Ibrahim, Muhammad; Li, Bin; Zhao, Wen-Jun; Chen, Gong-You; Zhu, Bo; Xie, Guan-Lin

    2014-01-01

    Acidovorax avenae subsp. avenae is the causal agent of bacterial brown stripe disease in rice. In this study, we characterized a novel horizontal transfer of a gene cluster, including tetR, on the chromosome of A. avenae subsp. avenae RS-1 by genome-wide analysis. TetR acted as a repressor in this gene cluster and the oxidative stress resistance was enhanced in tetR-deletion mutant strain. Electrophoretic mobility shift assay demonstrated that TetR regulator bound directly to the promoter of this gene cluster. Consistently, the results of quantitative real-time PCR also showed alterations in expression of associated genes. Moreover, the proteins affected by TetR under oxidative stress were revealed by comparing proteomic profiles of wild-type and mutant strains via 1D SDS-PAGE and LC-MS/MS analyses. Taken together, our results demonstrated that tetR gene in this novel gene cluster contributed to cell survival under oxidative stress, and TetR protein played an important regulatory role in growth kinetics, biofilm-forming capability, superoxide dismutase and catalase activity, and oxide detoxicating ability.

  12. A Practical Device for Measuring the Luminance Distribution

    Directory of Open Access Journals (Sweden)

    Thijs Kruisselbrink

    2017-06-01

    Full Text Available Various applications in building lighting such as automated daylight systems, dynamic lighting control systems, lighting simulations, and glare analyzes can be optimized using information on the actual luminance distributions of the surroundings. Currently, commercially available luminance distribution measurement devices are often not suitable for these kind of applications or simply too expensive for broad application. This paper describes the development of a practical and autonomous luminance distribution measurement device based on a credit card-sized single-board computer and a camera system. The luminance distribution was determined by capturing High Dynamic Range images and translating the RGB information to the CIE XYZ color space. The High Dynamic Range technology was essential to accurately capture the data needed to calculate the luminance distribution because it allows to capture luminance ranges occurring in real scenarios. The measurement results were represented in accordance with established methods in the field of daylighting. Measurements showed that the accuracy of the luminance distribution measurement device ranged from 5% to 20% (worst case which was deemed acceptable for practical measurements and broad applications in the building realm.

  13. An S/T-Q cluster domain census unveils new putative targets under Tel1/Mec1 control

    Directory of Open Access Journals (Sweden)

    Cheung Hannah C

    2012-11-01

    Full Text Available Abstract Background The cellular response to DNA damage is immediate and highly coordinated in order to maintain genome integrity and proper cell division. During the DNA damage response (DDR, the sensor kinases Tel1 and Mec1 in Saccharomyces cerevisiae and ATM and ATR in human, phosphorylate multiple mediators which activate effector proteins to initiate cell cycle checkpoints and DNA repair. A subset of kinase substrates are recognized by the S/T-Q cluster domain (SCD, which contains motifs of serine (S or threonine (T followed by a glutamine (Q. However, the full repertoire of proteins and pathways controlled by Tel1 and Mec1 is unknown. Results To identify all putative SCD-containing proteins, we analyzed the distribution of S/T-Q motifs within verified Tel1/Mec1 targets and arrived at a unifying SCD definition of at least 3 S/T-Q within a stretch of 50 residues. This new SCD definition was used in a custom bioinformatics pipeline to generate a census of SCD-containing proteins in both yeast and human. In yeast, 436 proteins were identified, a significantly larger number of hits than were expected by chance. These SCD-containing proteins did not distribute equally across GO-ontology terms, but were significantly enriched for those involved in processes related to the DDR. We also found a significant enrichment of proteins involved in telophase and cytokinesis, protein transport and endocytosis suggesting possible novel Tel1/Mec1 targets in these pathways. In the human proteome, a wide range of similar proteins were identified, including homologs of some SCD-containing proteins found in yeast. This list also included high concentrations of proteins in the Mediator, spindle pole body/centrosome and actin cytoskeleton complexes. Conclusions Using a bioinformatic approach, we have generated a census of SCD-containing proteins that are involved not only in known DDR pathways but several other pathways under Tel1/Mec1 control suggesting new

  14. Investigating a multigene prognostic assay based on significant pathways for Luminal A breast cancer through gene expression profile analysis.

    Science.gov (United States)

    Gao, Haiyan; Yang, Mei; Zhang, Xiaolan

    2018-04-01

    The present study aimed to investigate potential recurrence-risk biomarkers based on significant pathways for Luminal A breast cancer through gene expression profile analysis. Initially, the gene expression profiles of Luminal A breast cancer patients were downloaded from The Cancer Genome Atlas database. The differentially expressed genes (DEGs) were identified using a Limma package and the hierarchical clustering analysis was conducted for the DEGs. In addition, the functional pathways were screened using Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses and rank ratio calculation. The multigene prognostic assay was exploited based on the statistically significant pathways and its prognostic function was tested using train set and verified using the gene expression data and survival data of Luminal A breast cancer patients downloaded from the Gene Expression Omnibus. A total of 300 DEGs were identified between good and poor outcome groups, including 176 upregulated genes and 124 downregulated genes. The DEGs may be used to effectively distinguish Luminal A samples with different prognoses verified by hierarchical clustering analysis. There were 9 pathways screened as significant pathways and a total of 18 DEGs involved in these 9 pathways were identified as prognostic biomarkers. According to the survival analysis and receiver operating characteristic curve, the obtained 18-gene prognostic assay exhibited good prognostic function with high sensitivity and specificity to both the train and test samples. In conclusion the 18-gene prognostic assay including the key genes, transcription factor 7-like 2, anterior parietal cortex and lymphocyte enhancer factor-1 may provide a new method for predicting outcomes and may be conducive to the promotion of precision medicine for Luminal A breast cancer.

  15. Hydrodynamics of vapor-liquid annular dispersed flows in channels with heated rod clusters under unsteady conditions

    International Nuclear Information System (INIS)

    Kroshilin, A.E.; Kroshilin, V.E.; Nigmatulin, B.I.

    1984-01-01

    A one-dimensional unsteady hydrodynamic model of vapour-liquid disperse-annular flows in channels with heated fuel rod clusters has been constructed. Regularities in the appearance of critical heat transfer due to the dryout of a near-wall liquid film on rod surfaces in such channels are investigated. The model developed takes into account the main flow regularities in the channels with heated rod clusters. The calculations made have shown that the time before crisis appearance agrees satisfactorily with the experimental data

  16. Different responses of spontaneous and stimulus-related alpha activity to ambient luminance changes.

    Science.gov (United States)

    Benedetto, Alessandro; Lozano-Soldevilla, Diego; VanRullen, Rufin

    2017-12-04

    Alpha oscillations are particularly important in determining our percepts and have been implicated in fundamental brain functions. Oscillatory activity can be spontaneous or stimulus-related. Furthermore, stimulus-related responses can be phase- or non-phase-locked to the stimulus. Non-phase-locked (induced) activity can be identified as the average amplitude changes in response to a stimulation, while phase-locked activity can be measured via reverse-correlation techniques (echo function). However, the mechanisms and the functional roles of these oscillations are far from clear. Here, we investigated the effect of ambient luminance changes, known to dramatically modulate neural oscillations, on spontaneous and stimulus-related alpha. We investigated the effect of ambient luminance on EEG alpha during spontaneous human brain activity at rest (experiment 1) and during visual stimulation (experiment 2). Results show that spontaneous alpha amplitude increased by decreasing ambient luminance, while alpha frequency remained unaffected. In the second experiment, we found that under low-luminance viewing, the stimulus-related alpha amplitude was lower, and its frequency was slightly faster. These effects were evident in the phase-locked part of the alpha response (echo function), but weaker or absent in the induced (non-phase-locked) alpha responses. Finally, we explored the possible behavioural correlates of these modulations in a monocular critical flicker frequency task (experiment 3), finding that dark adaptation in the left eye decreased the temporal threshold of the right eye. Overall, we found that ambient luminance changes impact differently on spontaneous and stimulus-related alpha expression. We suggest that stimulus-related alpha activity is crucial in determining human temporal segmentation abilities. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  17. Calibrating photometric redshifts of luminous red galaxies

    International Nuclear Information System (INIS)

    Padmanabhan, Nikhil; Budavari, Tamas; Schlegel, David J.; Bridges, Terry; Brinkmann, Jonathan

    2005-01-01

    We discuss the construction of a photometric redshift catalogue of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS), emphasizing the principal steps necessary for constructing such a catalogue: (i) photometrically selecting the sample, (ii) measuring photometric redshifts and their error distributions, and (iii) estimating the true redshift distribution. We compare two photometric redshift algorithms for these data and find that they give comparable results. Calibrating against the SDSS and SDSS–2dF (Two Degree Field) spectroscopic surveys, we find that the photometric redshift accuracy is σ~ 0.03 for redshifts less than 0.55 and worsens at higher redshift (~ 0.06 for z < 0.7). These errors are caused by photometric scatter, as well as systematic errors in the templates, filter curves and photometric zero-points. We also parametrize the photometric redshift error distribution with a sum of Gaussians and use this model to deconvolve the errors from the measured photometric redshift distribution to estimate the true redshift distribution. We pay special attention to the stability of this deconvolution, regularizing the method with a prior on the smoothness of the true redshift distribution. The methods that we develop are applicable to general photometric redshift surveys.

  18. The effect of chromatic and luminance information on reaction times.

    Science.gov (United States)

    O'Donell, Beatriz M; Barraza, Jose F; Colombo, Elisa M

    2010-07-01

    We present a series of experiments exploring the effect of chromaticity on reaction time (RT) for a variety of stimulus conditions, including chromatic and luminance contrast, luminance, and size. The chromaticity of these stimuli was varied along a series of vectors in color space that included the two chromatic-opponent-cone axes, a red-green (L-M) axis and a blue-yellow [S - (L + M)] axis, and intermediate noncardinal orientations, as well as the luminance axis (L + M). For Weber luminance contrasts above 10-20%, RTs tend to the same asymptote, irrespective of chromatic direction. At lower luminance contrast, the addition of chromatic information shortens the RT. RTs are strongly influenced by stimulus size when the chromatic stimulus is modulated along the [S - (L + M)] pathway and by stimulus size and adaptation luminance for the (L-M) pathway. RTs are independent of stimulus size for stimuli larger than 0.5 deg. Data are modeled with a modified version of Pieron's formula with an exponent close to 2, in which the stimulus intensity term is replaced by a factor that considers the relative effects of chromatic and achromatic information, as indexed by the RMS (square-root of the cone contrast) value at isoluminance and the Weber luminance contrast, respectively. The parameters of the model reveal how RT is linked to stimulus size, chromatic channels, and adaptation luminance and how they can be interpreted in terms of two chromatic mechanisms. This equation predicts that, for isoluminance, RTs for a stimulus lying on the S-cone pathway are higher than those for a stimulus lying on the L-M-cone pathway, for a given RMS cone contrast. The equation also predicts an asymptotic trend to the RT for an achromatic stimulus when the luminance contrast is sufficiently large.

  19. THE ASSEMBLY OF GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Berrier, Joel C.; Stewart, Kyle R.; Bullock, James S.; Purcell, Chris W.; Barton, Elizabeth J.; Wechsler, Risa H.

    2009-01-01

    We study the formation of 53 galaxy cluster-size dark matter halos (M = 10 14.0-14.76 M sun ) formed within a pair of cosmological Λ cold dark matter N-body simulations, and track the accretion histories of cluster subhalos with masses large enough to host ∼0.3 L * galaxies. By associating subhalos with cluster galaxies, we find the majority of galaxies in clusters experience no 'preprocessing' in the group environment prior to their accretion into the cluster. On average, 70% of cluster galaxies fall into the cluster potential directly from the field, with no luminous companions in their host halos at the time of accretion; less than 12% are accreted as members of groups with five or more galaxies. Moreover, we find that cluster galaxies are significantly less likely to have experienced a merger in the recent past (∼<6 Gyr) than a field halo of the same mass. These results suggest that local cluster processes such as ram pressure stripping, galaxy harassment, or strangulation play the dominant role in explaining the difference between cluster and field populations at a fixed stellar mass, and that pre-evolution or past merging in the group environment is of secondary importance for setting cluster galaxy properties for most clusters. The accretion times for z = 0 cluster members are quite extended, with ∼20% incorporated into the cluster halo more than 7 Gyr ago and ∼20% within the last 2 Gyr. By comparing the observed morphological fractions in cluster and field populations, we estimate an approximate timescale for late-type to early-type transformation within the cluster environment to be ∼6 Gyr.

  20. Reduced-dimension power allocation over clustered channels in cognitive radios system under co-channel interference

    KAUST Repository

    Ben Ghorbel, Mahdi

    2014-05-12

    The objective of this paper is to propose a reduceddimension resource allocation scheme in the context of cognitive radio system in presence of co-channel interference between users. We assume a multicarrier transmission for both the primary and secondary systems. Instead of optimizing the powers over all sub-carriers, the sub-carriers are grouped into clusters of sub-carriers, where the power of each sub-carrier is directly related to the power of the correspondent cluster. The power optimization is done only over the set of clusters instead of all sub-carriers which can significantly reduce the complexity of the resource allocation problem. The performance loss of the reduced dimension solution with respect to the optimal solution, where the optimization is carried over all active sub-carriers, allows trading-off complexity versus performance. Numerical evaluation indeed revealed that a limited performance loss occurs by optimizing over a reduced set of clusters instead of the full optimization in the context of cognitive radio systems.

  1. Intelligent Luminance Control of Lighting Systems Based on Imaging Sensor Feedback

    Directory of Open Access Journals (Sweden)

    Haoting Liu

    2017-02-01

    Full Text Available An imaging sensor-based intelligent Light Emitting Diode (LED lighting system for desk use is proposed. In contrast to the traditional intelligent lighting system, such as the photosensitive resistance sensor-based or the infrared sensor-based system, the imaging sensor can realize a finer perception of the environmental light; thus it can guide a more precise lighting control. Before this system works, first lots of typical imaging lighting data of the desk application are accumulated. Second, a series of subjective and objective Lighting Effect Evaluation Metrics (LEEMs are defined and assessed for these datasets above. Then the cluster benchmarks of these objective LEEMs can be obtained. Third, both a single LEEM-based control and a multiple LEEMs-based control are developed to realize a kind of optimal luminance tuning. When this system works, first it captures the lighting image using a wearable camera. Then it computes the objective LEEMs of the captured image and compares them with the cluster benchmarks of the objective LEEMs. Finally, the single LEEM-based or the multiple LEEMs-based control can be implemented to get a kind of optimal lighting effect. Many experiment results have shown the proposed system can tune the LED lamp automatically according to environment luminance changes.

  2. Seasonal and geographic distribution of luminous bacteria in the eastern mediterranean sea and the gulf of elat.

    Science.gov (United States)

    Yetinson, T; Shilo, M

    1979-06-01

    Luminous bacteria in the Mediterranean Sea and the Gulf of Aqaba-Elat have different distribution patterns. In the Mediterranean Sea, Beneckea harveyi is present all year round, with different subtypes alternating in summer and winter; Photobacterium fischeri was only present during the winter. In the Gulf of Elat, P. leiognathi is present throughout the water column in similar densities during the entire year. This constancy in distribution is presumably due to the near-constancy in water temperature. In summer, Photobacterium leiognathi is replaced by B. harveyi in coastal surface waters. In the hypersaline Bardawil lagoon, only B. harveyi types are present. P. fischeri, a major component of the Mediterranean Sea winter communities, is absent from the lagoon. Luminous Beneckea strains show a great diversity in properties, e.g. temperature range for growth, sensitivity to infection by phages, sensitivity to attack by Bdellovibrio strains, and differences in tolerance to high-salinity shock. Therefore, subdivision of the taxonomic cluster of B. harveyi into subtypes is indicated. The composition of the luminous bacteria communities may serve as indicators of different marine water bodies. The symbiotic luminous bacteria of the light organ of the common Gulf of Elat fish, Photoblepharon palbebratus steinitzi, is different from any of the types described.

  3. WARM MOLECULAR GAS IN LUMINOUS INFRARED GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Lu, N.; Zhao, Y.; Xu, C. K.; Mazzarella, J. M.; Howell, J.; Appleton, P.; Lord, S.; Schulz, B. [Infrared Processing and Analysis Center, California Institute of Technology, MS 100-22, Pasadena, CA 91125 (United States); Gao, Y. [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Armus, L.; Díaz-Santos, T.; Surace, J. [Spitzer Science Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States); Isaak, K. G. [ESA Astrophysics Missions Division, ESTEC, P.O. Box 299, 2200-AG Noordwijk (Netherlands); Petric, A. O. [Gemini Observatory, 670 N. A' ohoku Place, Hilo, HI 96720 (United States); Charmandaris, V. [Department of Physics, University of Crete, GR-71003 Heraklion (Greece); Evans, A. S. [Department of Astronomy, University of Virginia, 530 McCormick Road, Charlottesville, VA 22904 (United States); Inami, H. [National Optical Astronomy Observatory, Tucson, AZ 85719 (United States); Iwasawa, K. [ICREA and Institut de Ciències del Cosmos (ICC), Universitat de Barcelona (IEEC-UB), Martí i Franquès 1, E-08028 Barcelona (Spain); Leech, J. [Department of Physics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Sanders, D. B., E-mail: lu@ipac.caltech.edu [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); and others

    2014-06-01

    We present our initial results on the CO rotational spectral line energy distribution (SLED) of the J to J–1 transitions from J = 4 up to 13 from Herschel SPIRE spectroscopic observations of 65 luminous infrared galaxies (LIRGs) in the Great Observatories All-Sky LIRG Survey. The observed SLEDs change on average from one peaking at J ≤ 4 to a broad distribution peaking around J ∼ 6 to 7 as the IRAS 60-to-100 μm color, C(60/100), increases. However, the ratios of a CO line luminosity to the total infrared luminosity, L {sub IR}, show the smallest variation for J around 6 or 7. This suggests that, for most LIRGs, ongoing star formation (SF) is also responsible for a warm gas component that emits CO lines primarily in the mid-J regime (5 ≲ J ≲ 10). As a result, the logarithmic ratios of the CO line luminosity summed over CO (5–4), (6–5), (7–6), (8–7) and (10–9) transitions to L {sub IR}, log R {sub midCO}, remain largely independent of C(60/100), and show a mean value of –4.13 (≡log R{sub midCO}{sup SF}) and a sample standard deviation of only 0.10 for the SF-dominated galaxies. Including additional galaxies from the literature, we show, albeit with a small number of cases, the possibility that galaxies, which bear powerful interstellar shocks unrelated to the current SF, and galaxies, in which an energetic active galactic nucleus contributes significantly to the bolometric luminosity, have their R {sub midCO} higher and lower than R{sub midCO}{sup SF}, respectively.

  4. Production of L-Asparaginase by the marine luminous bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    Fortythree strains of luminous bacteria, belonging to 4 species, (Vibrio harveyi, V. fischeri, Photobacterium leiognathi and P. phosphoreum) isolated from different marine samples, were examined for the production of L-asparaginase. Presence...

  5. Study on the luminous characteristics of a natural ball lightning

    Science.gov (United States)

    Wang, Hao; Yuan, Ping; Cen, Jianyong; Liu, Guorong

    2018-02-01

    According to the optical images of the whole process of a natural ball lightning recorded by two slit-less spectrographs in the Qinghai plateau of China, the simulated observation experiment on the luminous intensity of the spherical light source was carried out. The luminous intensity and the optical power of the natural ball lightning in the wavelength range of 400-690 nm were estimated based on the experimental data and the Lambert-Beer Law. The results show that the maximum luminous intensity was about 1.24 × 105 cd in the initial stage of the natural ball lightning, and the maximum luminous intensity and the maximum optical power in most time of its life were about 5.9 × 104 cd and 4.2 × 103 W, respectively.

  6. Geometry of illumination, luminance contrast, and gloss perception

    OpenAIRE

    Leloup, Frédéric; Pointer, Michael R.; Dutré, Philip; Hanselaer, Peter

    2010-01-01

    The influence of both the geometry of illumination and luminance contrast on gloss perception has been examined using the method of paired comparison. Six achromatic glass samples having different lightness were illuminated by two light sources. Only one of these light sources was visible in reflection by the observer. By separate adjustment of the intensity of both light sources, the luminance of both the reflected image and the adjacent off-specular surroundings could be individually varied...

  7. Clustering behaviour in an Al-Mg-Si-Cu alloy during natural ageing and subsequent under-ageing

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lingfei, E-mail: lingfei.cao@monash.edu [ARC Centre of Excellence for Design in Light Metals, Monash University, G68, Building 27, Welling Road, Clayton, Vic 3800 (Australia); Rometsch, Paul A.; Couper, Malcolm J. [ARC Centre of Excellence for Design in Light Metals, Monash University, G68, Building 27, Welling Road, Clayton, Vic 3800 (Australia)

    2013-01-01

    The clustering behaviour in an Al-Mg-Si-Cu alloy in the T4 and T61 tempers has been investigated by hardness and electrical conductivity testing, along with nanostructural characterisation using 3-D atom probe (3DAP) analysis. The selection of parameters for the PoSAP and IVAS cluster analysis software tools is discussed. The results show that the T4 hardness increases significantly within one day of natural ageing, and then reaches a plateau after about a week. A contingency table analysis reveals that clustering between Mg and Si atoms already exists in the T4 condition with only 1.1 h of natural ageing. In the T61 condition (after 0.5 h at 170 Degree-Sign C), the hardness is greatest in samples aged immediately after quenching, and decreases very rapidly with increasing prior natural ageing times of up to 3 h. The initial hardness drop in the T61 condition is associated with decreases in the volume fraction, average size and maximum size of solute aggregates. Longer prior natural ageing times inhibit the formation of larger solute aggregates (with more than 75 detected Mg+Si+Cu atoms) and thus result in low levels of T61 hardness.

  8. Clustering behaviour in an Al–Mg–Si–Cu alloy during natural ageing and subsequent under-ageing

    International Nuclear Information System (INIS)

    Cao, Lingfei; Rometsch, Paul A.; Couper, Malcolm J.

    2013-01-01

    The clustering behaviour in an Al–Mg–Si–Cu alloy in the T4 and T61 tempers has been investigated by hardness and electrical conductivity testing, along with nanostructural characterisation using 3-D atom probe (3DAP) analysis. The selection of parameters for the PoSAP and IVAS cluster analysis software tools is discussed. The results show that the T4 hardness increases significantly within one day of natural ageing, and then reaches a plateau after about a week. A contingency table analysis reveals that clustering between Mg and Si atoms already exists in the T4 condition with only 1.1 h of natural ageing. In the T61 condition (after 0.5 h at 170 °C), the hardness is greatest in samples aged immediately after quenching, and decreases very rapidly with increasing prior natural ageing times of up to 3 h. The initial hardness drop in the T61 condition is associated with decreases in the volume fraction, average size and maximum size of solute aggregates. Longer prior natural ageing times inhibit the formation of larger solute aggregates (with more than 75 detected Mg+Si+Cu atoms) and thus result in low levels of T61 hardness.

  9. Predicting daylight illuminance on inclined surfaces using sky luminance data

    Energy Technology Data Exchange (ETDEWEB)

    Li, D.H.W.; Lau, C.C.S.; Lam, J.C. [City University of Hong Kong, Kowloon (China). Dept. of Building and Construction

    2005-07-01

    Daylight illuminance, particularly on vertical surfaces, plays a major role in determining and evaluating the daylighting performance of a building. In many parts of the world, however, the basic daylight illuminance data for various vertical planes are not always readily available. The usual method to obtain diffuse illuminance on tilted planes would be based on inclined surface models using data from the horizontal measurements. Alternatively, the diffuse illuminance on a sloping plane can be computed by integrating the luminance distribution of the sky 'seen' by the plane. This paper presents an approach to estimate the vertical outdoor illuminance from sky luminance data and solar geometry. Sky luminance data recorded from January 1999 to December 2001 in Hong Kong and generated by two well-known sky luminance models (Kittler and Perez) were used to compute the outdoor illuminance for the four principal vertical planes (N, E, S and W). The performance of this approach was evaluated against data measured in the same period. Statistical analysis indicated that using sky luminance distributions to predict outdoor illuminance can give reasonably good agreement with measured data for all vertical surfaces. The findings provide an accurate alternative to determine the amount of daylight on vertical as well as other inclined surfaces when sky luminance data are available. (author)

  10. Dynamics of backlight luminance for using smartphone in dark environment

    Science.gov (United States)

    Na, Nooree; Jang, Jiho; Suk, Hyeon-Jeong

    2014-02-01

    This study developed dynamic backlight luminance, which gradually changes as time passes for comfortable use of a smartphone display in a dark environment. The study was carried out in two stages. In the first stage, a user test was conducted to identify the optimal luminance by assessing the facial squint level, subjective glare evaluation, eye blink frequency and users' subjective preferences. Based on the results of the user test, the dynamics of backlight luminance was designed. It has two levels of luminance: the optimal level for initial viewing to avoid sudden glare or fatigue to users' eyes, and the optimal level for constant viewing, which is comfortable, but also bright enough for constant reading of the displayed material. The luminance for initial viewing starts from 10 cd/m2, and it gradually increases to 40 cd/m2 for users' visual comfort at constant viewing for 20 seconds; In the second stage, a validation test on dynamics of backlight luminance was conducted to verify the effectiveness of the developed dynamics. It involving users' subjective preferences, eye blink frequency, and brainwave analysis using the electroencephalogram (EEG) to confirm that the proposed dynamic backlighting enhances users' visual comfort and visual cognition, particularly for using smartphones in a dark environment.

  11. Detection of chromatic and luminance distortions in natural scenes.

    Science.gov (United States)

    Jennings, Ben J; Wang, Karen; Menzies, Samantha; Kingdom, Frederick A A

    2015-09-01

    A number of studies have measured visual thresholds for detecting spatial distortions applied to images of natural scenes. In one study, Bex [J. Vis.10(2), 1 (2010)10.1167/10.2.231534-7362] measured sensitivity to sinusoidal spatial modulations of image scale. Here, we measure sensitivity to sinusoidal scale distortions applied to the chromatic, luminance, or both layers of natural scene images. We first established that sensitivity does not depend on whether the undistorted comparison image was of the same or of a different scene. Next, we found that, when the luminance but not chromatic layer was distorted, performance was the same regardless of whether the chromatic layer was present, absent, or phase-scrambled; in other words, the chromatic layer, in whatever form, did not affect sensitivity to the luminance layer distortion. However, when the chromatic layer was distorted, sensitivity was higher when the luminance layer was intact compared to when absent or phase-scrambled. These detection threshold results complement the appearance of periodic distortions of the image scale: when the luminance layer is distorted visibly, the scene appears distorted, but when the chromatic layer is distorted visibly, there is little apparent scene distortion. We conclude that (a) observers have a built-in sense of how a normal image of a natural scene should appear, and (b) the detection of distortion in, as well as the apparent distortion of, natural scene images is mediated predominantly by the luminance layer and not chromatic layer.

  12. Tritium pollution in the Swiss luminous compound industry

    International Nuclear Information System (INIS)

    Krejci, K.; Zeller, Jr.

    1979-01-01

    The Swiss luminous compound industry is an important consumer of tritium. About 350kCi go into production of tritium gas-filled light sources and 40kCi into production of tritium luminous compound annually. To illustrate the pollution problem, a factory is mentioned that handles 200kCi annually and a chain of luminizers, processing 20kCi over the same period as tritium luminous compound. This material is manufactured by coating phosphors with tritiated polystyrene having a specific activity up to 200Ci/g. Because of the high specific activity, the radiation damage produces an average activity release of 5.2% annually, which is one of the main reasons for public and occupational exposure. The processing of large quantities of tritium gas requires special equipment, such as units made entirely of stainless steel for purification and hydrogenation, oxidation systems for highly contaminated air, glove boxes, ventilation and monitoring systems. Nevertheless, contamination of air, surfaces, water and workers cannot be avoided. Only in a few cases were MPC-values for tritium content in urine of workers exceeded. From these results, biological half-lives between 5-15 days were estimated. Regular medical examinations showed no significant influence in blood picture parameters, except in one single case with a tritium concentration in urine of 2.8mCi/litre. Entirely different problems arise in most luminizing factories where luminous paint is processed as an open radioactive source. (author)

  13. Ensemble attribute profile clustering: discovering and characterizing groups of genes with similar patterns of biological features

    Directory of Open Access Journals (Sweden)

    Bissell MJ

    2006-03-01

    contained groups of genes with the functional properties of membrane receptor biology/signal transduction and nucleic acid binding/transcription. A subset of the luminal markers was associated with metabolic and oxidoreductase activities, whereas a subset of myoepithelial markers was associated with protein hydrolase activity. Conclusion Given a set of genes and/or proteins associated with a phenomenon, process or system of interest, ensemble attribute profile clustering provides a simple method for collating and sythesizing the annotation data pertaining to them that are present in text-based, gene-centered corpora. The results provide information about properties common and unique to subsets of the list and hence insights into the biology of the problem under investigation.

  14. Symbiotic association of Photobacterium fischeri with the marine luminous fish Monocentris japonica; a model of symbiosis based on bacterial studies.

    Science.gov (United States)

    Ruby, E G; Nealson, K H

    1976-12-01

    Isolation of bacteria from the luminous organ of the fish Monocentris japonica has revealed that the organ contains a pure culture of luminous bacteria. For the four fish examined, all contained Photobacterium fischeri as their luminous bacterial symbiont. This is the first time that P. fischeri has been identified in a symbiotic association. A representative isolate (MJl) of the light organ population was selected for in vivo studies of its luminous system. Several physiological features suggest adaptation for symbiotic existence. First, MJl has been shown to produce and respond to an inducer of luciferase that could accumulate in the light organ. Secondly, the specific activity of light production was seen to be maximal under low, growth-limiting concentrations of oxygen. Thirdly, unlike another luminous species (Beneckea harveyi), synthesis of the light production system of these bacteria is not catabolite repressed by glucose--a possible source of nutrition in the light organ. Fourthly, when grown aerobically on glucose these bacteria excrete pyruvic acid into the medium. This production of pyruvate is a major process, accounting for 30-40% of the glucose utilized and may serve as a form of regulatory and nutritional communication with the host.

  15. Luciferase genes cloned from the unculturable luminous bacteroid symbiont of the Caribbean flashlight fish, Kryptophanaron alfredi.

    Science.gov (United States)

    Haygood, M G; Cohn, D H

    1986-01-01

    Light organs of anomalopid (flashlight) fish contain luminous bacteroids that have never been cultured and, consequently, have been difficult to study. We have characterized the luciferase (lux) region of DNA extracted from light organs of the Caribbean flashlight fish Kryptophanaron alfredi by hybridization of cloned Vibrio harveyi lux genes to restriction-endonuclease-digested, light organ DNA. Comparison of the hybridization pattern of light organ DNA with that of DNA of a putative symbiotic isolate provides a method for identifying the authentic luminous symbiont regardless of its luminescence, and was used to reject one such isolate. Light organ DNA was further used to construct a cosmid clone bank and the luciferase genes were isolated. Unlike other bacterial luciferase genes, the genes were not expressed in Escherichia coli. When placed under the control of the E. coli trp promoter, the genes were transcribed but no luciferase was detected, suggesting a posttranscriptional block to expression.

  16. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity

    International Nuclear Information System (INIS)

    Kudryasheva, N.S.; Rozhko, T.V.

    2015-01-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1 – absence of effects (stress recognition), 2 – activation (adaptive response), and 3 – inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. - Highlights: • Luminous bacteria demonstrate nonlinear dose-effect relation in radioactive solutions. • Response to low-dose radiation includes 3 stages: threshold, activation, inhibition. • ROS are responsible for low-dose effects of alpha-emitting radionuclides. • Luminous marine bacteria are a convenient tool to study radiation hormesis

  17. Enhanced luminance for inorganic electroluminescent devices with a charged electret

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Fang-Hsing, E-mail: fansen@dragon.nchu.edu.tw [Department of Electrical Engineering and Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China); Chen, Kuo-Feng [Department of Electrical Engineering and Graduate Institute of Optoelectronic Engineering, National Chung Hsing University, Taichung 402, Taiwan, ROC (China); Display Technology Center/Industrial Technology Research Institute, Hsinchu 310, Taiwan, ROC (China); Chien, Yu-Han; Chang, Chin-Chia; Chuang, Meng-Ying [Display Technology Center/Industrial Technology Research Institute, Hsinchu 310, Taiwan, ROC (China)

    2013-09-15

    This work proposes a novel inorganic electroluminescent (IEL) device with an electric field built-in (EFBI) technique to reduce its driving voltage and enhance its luminance. The EFBI technique was performed by charging an electret comprising a silicon dioxide film at different temperatures (25–150 °C) in powder electroluminescent (PDEL) devices. The driving voltage of the EFBI-PDEL device decreased by 61.4 V (or 20.5%) under the brightness of 269 cd/m{sup 2}, and its brightness increased by 128 cd/m{sup 2} (or 47%) at ac 300 V. The efficiency of the EFBI-PDEL device significantly increased by 0.827 lm/W (or 45.5%) at ac 300 V. The proposed EFBI-PDEL device has advantages of a low-temperature process and low cost, and potential for large-area display applications. -- Highlights: • An electric-field built-in powder electroluminescent (EFBI-PDEL) device is proposed. • The EFBI technique is performed by charging an electrets. • The driving voltage of the EFBI-PDEL device decreased by 20.5%. • The brightness of the EFBI-PDEL device increased by 47%. • The efficiency of the EFBI-PDEL device increased by 45.5%.

  18. Tritium application: self-luminous glass tube(SLGT)

    International Nuclear Information System (INIS)

    Kim, K.; Lee, S.K.; Chung, E.S.; Kim, K.S.; Kim, W.S.; Nam, G.J.

    2005-01-01

    To manufacture SLGTs (self-luminous glass tubes), 4 core technologies are needed: coating technology, tritium injection technology, laser sealing/cutting technology and tritium handling technology. The inside of the glass tubes is coated with greenish ZnS phosphor particles with sizes varying from 4∝5 [μm], and Cu, and Al as an activator and a co-dopant, respectively. We also found that it would be possible to produce a phosphor coated glass tube for the SLGT using the well established cold cathode fluorescent lamp (CCFL) bulb manufacturing technology. The conceptual design of the main process loop (PL) is almost done. A delicate technique will be needed for the sealing/cutting of the glass tubes. Instead of the existing torch technology, a new technology using a pulse-type laser is under investigation. The design basis of the tritium handling facilities is to minimize the operator's exposure to tritium uptake and the emission of tritium to the environment. To fulfill the requirements, major tritium handling components are located in the secondary containment such as the glove boxes (GBs) and/or the fume hoods. The tritium recovery system (TRS) is connected to a GB and PL to minimize the release of tritium as well as to remove the moisture and oxygen in the GB. (orig.)

  19. Tritium application: self-luminous glass tube(SLGT)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, K.; Lee, S.K.; Chung, E.S.; Kim, K.S.; Kim, W.S. [Nuclear Power Lab., Korea Electric Power Research Inst. (KEPRI), Daejeon (Korea); Nam, G.J. [Engineering Information Technology Center, Inst. for Advanced Engineering (IAE), Kyonggi-do (Korea)

    2005-07-01

    To manufacture SLGTs (self-luminous glass tubes), 4 core technologies are needed: coating technology, tritium injection technology, laser sealing/cutting technology and tritium handling technology. The inside of the glass tubes is coated with greenish ZnS phosphor particles with sizes varying from 4{proportional_to}5 [{mu}m], and Cu, and Al as an activator and a co-dopant, respectively. We also found that it would be possible to produce a phosphor coated glass tube for the SLGT using the well established cold cathode fluorescent lamp (CCFL) bulb manufacturing technology. The conceptual design of the main process loop (PL) is almost done. A delicate technique will be needed for the sealing/cutting of the glass tubes. Instead of the existing torch technology, a new technology using a pulse-type laser is under investigation. The design basis of the tritium handling facilities is to minimize the operator's exposure to tritium uptake and the emission of tritium to the environment. To fulfill the requirements, major tritium handling components are located in the secondary containment such as the glove boxes (GBs) and/or the fume hoods. The tritium recovery system (TRS) is connected to a GB and PL to minimize the release of tritium as well as to remove the moisture and oxygen in the GB. (orig.)

  20. Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal Like, Luminal A, and Luminal B Breast Cancers

    Science.gov (United States)

    2016-10-01

    will be further analyzed for effects on reading frame and protein structure and function using analysis and prediction tools such as PolyPhen and...luminal A, and luminal B tumors. Originally this study intended to include 900 newly diagnosed first primary triple negative (TN) invasive breast cancer...breast cancer risk factors. At the end of the interview participants will be asked to donate an oral tissue specimen for future genetic testing. Medical

  1. The role of luminance and chromatic cues in emmetropisation.

    Science.gov (United States)

    Rucker, Frances J

    2013-05-01

    At birth most, but not all eyes, are hyperopic. Over the course of the first few years of life the refraction gradually becomes close to zero through a process called emmetropisation. This process is not thought to require accommodation, though a lag of accommodation has been implicated in myopia development, suggesting that the accuracy of accommodation is an important factor. This review will cover research on accommodation and emmetropisation that relates to the ability of the eye to use colour and luminance cues to guide the responses. There are three ways in which changes in luminance and colour contrast could provide cues: (1) The eye could maximize luminance contrast. Monochromatic light experiments have shown that the human eye can accommodate and animal eyes can emmetropise using changes in luminance contrast alone. However, by reducing the effectiveness of luminance cues in monochromatic and white light by introducing astigmatism, or by reducing light intensity, investigators have revealed that the eye also uses colour cues in emmetropisation. (2) The eye could compare relative cone contrast to derive the sign of defocus information from colour cues. Experiments involving simulations of the retinal image with defocus have shown that relative cone contrast can provide colour cues for defocus in accommodation and emmetropisation. In the myopic simulation the contrast of the red component of a sinusoidal grating was higher than that of the green and blue component and this caused relaxation of accommodation and reduced eye growth. In the hyperopic simulation the contrast of the blue component was higher than that of the green and red components and this caused increased accommodation and increased eye growth. (3) The eye could compare the change in luminance and colour contrast as the eye changes focus. An experiment has shown that changes in colour or luminance contrast can provide cues for defocus in emmetropisation. When the eye is exposed to colour

  2. Varied Human Tolerance to the Combined Conditions of Low Contrast and Diminished Luminance: A Quasi-Meta Analysis

    Science.gov (United States)

    2017-08-30

    conditions (e.g., dry eyes , mild cataractous conditions, Stevens-Johnson Syndrome ) using CS alone as the performance index. More commonly, it has been...subjects tested under conditions of spherical blur, astigmatic blur, low luminance, and one eye vs. two eyes ...conditions). The vast majority of past mesopic visual performance studies were predominantly isolated to evaluations of various eye disease

  3. The zebrafish miR-462/miR-731 cluster is induced under hypoxic stress via hypoxia-inducible factor 1α and functions in cellular adaptations.

    Science.gov (United States)

    Huang, Chun-Xiao; Chen, Nan; Wu, Xin-Jie; Huang, Cui-Hong; He, Yan; Tang, Rong; Wang, Wei-Min; Wang, Huan-Ling

    2015-12-01

    Hypoxia, a unique and essential environmental stress, evokes highly coordinated cellular responses, and hypoxia-inducible factor (HIF) 1 in the hypoxia signaling pathway, an evolutionarily conserved cellular signaling pathway, acts as a master regulator of the transcriptional response to hypoxic stress. MicroRNAs (miRNAs), a major class of posttranscriptional gene expression regulators, also play pivotal roles in orchestrating hypoxia-mediated cellular adaptations. Here, global miRNA expression profiling and quantitative real-time PCR indicated that the up-regulation of the miR-462/miR-731 cluster in zebrafish larvae is induced by hypoxia. It was further validated that miR-462 and miR-731 are up-regulated in a Hif-1α-mediated manner under hypoxia and specifically target ddx5 and ppm1da, respectively. Overexpression of miR-462 and miR-731 represses cell proliferation through blocking cell cycle progress of DNA replication, and induces apoptosis. In situ detection revealed that the miR-462/miR-731 cluster is highly expressed in a consistent and ubiquitous manner throughout the early developmental stages. Additionally, the transcripts become restricted to the notochord, pharyngeal arch, liver, and gut regions from postfertilization d 3 to 5. These data highlight a previously unidentified role of the miR-462/miR-731 cluster as a crucial signaling mediator for hypoxia-mediated cellular adaptations and provide some insights into the potential function of the cluster during embryonic development. © FASEB.

  4. Closing the mind's eye: incoming luminance signals disrupt visual imagery.

    Directory of Open Access Journals (Sweden)

    Rachel Sherwood

    Full Text Available Mental imagery has been associated with many cognitive functions, both high and low-level. Despite recent scientific advances, the contextual and environmental conditions that most affect the mechanisms of visual imagery remain unclear. It has been previously shown that the greater the level of background luminance the weaker the effect of imagery on subsequent perception. However, in these experiments it was unclear whether the luminance was affecting imagery generation or storage of a memory trace. Here, we report that background luminance can attenuate both mental imagery generation and imagery storage during an unrelated cognitive task. However, imagery generation was more sensitive to the degree of luminance. In addition, we show that these findings were not due to differential dark adaptation. These results suggest that afferent visual signals can interfere with both the formation and priming-memory effects associated with visual imagery. It follows that background luminance may be a valuable tool for investigating imagery and its role in various cognitive and sensory processes.

  5. Association of proteasomal activity with metastasis in luminal breast cancer

    Science.gov (United States)

    Shashova, E. E.; Fesik, E. A.; Doroshenko, A. V.

    2017-09-01

    Chimotrypsin-like (ChTL) and caspase-like (CL) proteasomal activities were investigated in different variants of the tumor progression of luminal breast cancer. Patients with primary luminal breast cancer (n = 123) in stage T1-3N0-2M0 who had not received neoadjuvant treatment were included in this study. Proteasome ChTL and CL activities were determined in the samples of tumor and adjacent tissues. The coefficients of chymotrypsin-like (kChTL) and caspase-like (kCL) proteasome activity were also calculated as the ratio of the corresponding activity in the tumor tissue to activity in the adjacent tissue. ChTL, CL, kChTL and kCL in the tissues of luminal A and B breast cancer with lymphogenic metastasis were compared, and their association with hematogenous metastasis was evaluated. On the one hand, CL activity of proteasomes increased in luminal A breast cancer with extensive lymphogenic metastasis (N2), on the other hand it decreased in the luminal B subtype of cancer. The ratio of proteasomal activity in the tumor and adjacent tissues plays a significant role in the hematogenic pathway of breast cancer progression and is associated with poor metastatic-free survival.

  6. In Pursuit of the Least Luminous Galaxies

    Directory of Open Access Journals (Sweden)

    Beth Willman

    2010-01-01

    Full Text Available The dwarf galaxy companions to the Milky Way are unique cosmological laboratories. With luminosities as low as 10−7LMW, they inhabit the lowest mass dark matter halos known to host stars and are presently the most direct tracers of the distribution, mass spectrum, and clustering scale of dark matter. Their resolved stellar populations also facilitate detailed studies of their history and mass content. To fully exploit this potential requires a well-defined census of virtually invisible galaxies to the faintest possible limits and to the largest possible distances. I review the past and present impacts of survey astronomy on the census of Milky Way dwarf galaxy companions and discuss the future of finding ultra-faint dwarf galaxies around the Milky Way and beyond in wide-field survey data.

  7. Impact of Intestinal Microbiota on Intestinal Luminal Metabolome

    Science.gov (United States)

    Matsumoto, Mitsuharu; Kibe, Ryoko; Ooga, Takushi; Aiba, Yuji; Kurihara, Shin; Sawaki, Emiko; Koga, Yasuhiro; Benno, Yoshimi

    2012-01-01

    Low–molecular-weight metabolites produced by intestinal microbiota play a direct role in health and disease. In this study, we analyzed the colonic luminal metabolome using capillary electrophoresis mass spectrometry with time-of-flight (CE-TOFMS) —a novel technique for analyzing and differentially displaying metabolic profiles— in order to clarify the metabolite profiles in the intestinal lumen. CE-TOFMS identified 179 metabolites from the colonic luminal metabolome and 48 metabolites were present in significantly higher concentrations and/or incidence in the germ-free (GF) mice than in the Ex-GF mice (p metabolome and a comprehensive understanding of intestinal luminal metabolome is critical for clarifying host-intestinal bacterial interactions. PMID:22724057

  8. Luminal progenitors restrict their lineage potential during mammary gland development.

    Science.gov (United States)

    Rodilla, Veronica; Dasti, Alessandro; Huyghe, Mathilde; Lafkas, Daniel; Laurent, Cécile; Reyal, Fabien; Fre, Silvia

    2015-02-01

    The hierarchical relationships between stem cells and progenitors that guide mammary gland morphogenesis are still poorly defined. While multipotent basal stem cells have been found within the myoepithelial compartment, the in vivo lineage potential of luminal progenitors is unclear. Here we used the expression of the Notch1 receptor, previously implicated in mammary gland development and tumorigenesis, to elucidate the hierarchical organization of mammary stem/progenitor cells by lineage tracing. We found that Notch1 expression identifies multipotent stem cells in the embryonic mammary bud, which progressively restrict their lineage potential during mammary ductal morphogenesis to exclusively generate an ERαneg luminal lineage postnatally. Importantly, our results show that Notch1-labelled cells represent the alveolar progenitors that expand during pregnancy and survive multiple successive involutions. This study reveals that postnatal luminal epithelial cells derive from distinct self-sustained lineages that may represent the cells of origin of different breast cancer subtypes.

  9. Asymmetric effects of luminance and chrominance in the watercolor illusion

    Directory of Open Access Journals (Sweden)

    Andrew eCoia

    2014-09-01

    Full Text Available When bounded by a line of sufficient contrast, the desaturated hue of a colored line will spread over an enclosed area, an effect known as the watercolor illusion. The contrast of the two lines can be in luminance, chromaticity, or a combination of both. The effect is most salient when the enclosing line has greater contrast with the background than the line that induces the spreading color. In most prior experiments with watercolor spreading, the luminance of both lines has been lower than the background. An achromatic version of the illusion exists where a dark line will spread while being bounded by either a darker or brighter line. In a previous study we measured the strength of the watercolor effect in which the colored inducing line was isoluminant to the background, and found an illusion for both brighter and darker achromatic outer contours. We also found the strength of spreading is stronger for bluish (+S cone input colors compared to yellowish (-S cone input ones, when bounded by a dark line. The current study set out to measure the hue dependence of the watercolor illusion when inducing colors are flanked with brighter (increment as opposed to darker outer lines. The asymmetry in the watercolor effect with S cone input was enhanced when the inducing contrast was an increment rather than a decrement. Further experiments explored the relationship between the perceived contrast of these chromatic lines when paired with luminance increments and decrements and revealed that the perceived contrast of luminance increments and decrements is dependent on which isoluminant color they are paired with. In addition to known hue asymmetries in the watercolor illusion there are asymmetries between luminance increments and decrements that are also hue dependent. These latter asymmetries may be related to the perceived contrast of the hue/luminance parings.

  10. Asymmetric effects of luminance and chrominance in the watercolor illusion.

    Science.gov (United States)

    Coia, Andrew J; Crognale, Michael A

    2014-01-01

    When bounded by a line of sufficient contrast, the desaturated hue of a colored line will spread over an enclosed area, an effect known as the watercolor illusion. The contrast of the two lines can be in luminance, chromaticity, or a combination of both. The effect is most salient when the enclosing line has greater contrast with the background than the line that induces the spreading color. In most prior experiments with watercolor spreading, the luminance of both lines has been lower than the background. An achromatic version of the illusion exists where a dark line will spread while being bounded by either a darker or brighter line. In a previous study we measured the strength of the watercolor effect in which the colored inducing line was isoluminant to the background, and found an illusion for both brighter and darker achromatic outer contours. We also found the strength of spreading is stronger for bluish (+S cone input) colors compared to yellowish (-S cone input) ones, when bounded by a dark line. The current study set out to measure the hue dependence of the watercolor illusion when inducing colors are flanked with brighter (increment) as opposed to darker outer lines. The asymmetry in the watercolor effect with S cone input was enhanced when the inducing contrast was an increment rather than a decrement. Further experiments explored the relationship between the perceived contrast of these chromatic lines when paired with luminance increments and decrements and revealed that the perceived contrast of luminance increments and decrements is dependent on which isoluminant color they are paired with. In addition to known hue asymmetries in the watercolor illusion there are asymmetries between luminance increments and decrements that are also hue dependent. These latter asymmetries may be related to the perceived contrast of the hue/luminance parings.

  11. Human Mammary Luminal Epithelial Cells Contain Progenitors to Myoepithelial Cells

    Energy Technology Data Exchange (ETDEWEB)

    Pechoux, Christine; Gudjonsson, Thorarinn; Ronnov-Jessen, Lone; Bissell, Mina J; Petersen, Ole

    1999-02-01

    The origin of the epithelial and myoepithelial cells in the human breast has not been delineated. In this study we have addressed whether luminal epithelial cells and myoepithelial cells are vertically connected, i.e., whether one is the precursor for the other. We used a primary culture assay allowing preservation of basic phenotypic traits of luminal epithelial and myoepithelial cells in culture. The two cell types were then separated immunomagnetically using antibodies directed against lineage-specific cell surface antigens into at best 100% purity. The cellular identity was ascertained by cytochemistry, immunoblotting, and 2-D gel electrophoresis. Luminal epithelial cells were identified by strong expression of cytokeratins 18 and 19 while myoepithelial cells were recognized by expression of vimentin and {alpha}-smooth muscle actin. We used a previously devised culture medium (CDM4) that allows vigorous expansion of proliferative myoepithelial cells and also devised a medium (CDM6) that allowed sufficient expansion of differentiated luminal epithelial cells based on addition of hepatocyte growth factor/scatter factor. The two different culture media supported each lineage for at least five passages without signs of interconversion. We used parallel cultures where we switched culture media, thus testing the ability of each lineage to convert to the other. Whereas the myoepithelial lineage showed no signs of interconversion, a subset of luminal epithelial cells, gradually, but distinctly, converted to myoepithelial cells. We propose that in the mature human breast, it is the luminal epithelial cell compartment that gives rise to myoepithelial cells rather than the other way around.

  12. Formation mechanism of solute clusters under neutron irradiation in ferritic model alloys and in a reactor pressure vessel steel: clusters of defects; Mecanismes de fragilisation sous irradiation aux neutrons d'alliages modeles ferritiques et d'un acier de cuve: amas de defauts

    Energy Technology Data Exchange (ETDEWEB)

    Meslin-Chiffon, E

    2007-11-15

    The embrittlement of reactor pressure vessel (RPV) under irradiation is partly due to the formation of point defects (PD) and solute clusters. The aim of this work was to gain more insight into the formation mechanisms of solute clusters in low copper ([Cu] = 0.1 wt%) FeCu and FeCuMnNi model alloys, in a copper free FeMnNi model alloy and in a low copper French RPV steel (16MND5). These materials were neutron-irradiated around 300 C in a test reactor. Solute clusters were characterized by tomographic atom probe whereas PD clusters were simulated with a rate theory numerical code calibrated under cascade damage conditions using transmission electron microscopy analysis. The confrontation between experiments and simulation reveals that a heterogeneous irradiation-induced solute precipitation/segregation probably occurs on PD clusters. (author)

  13. A Blind Pilot: Who is a Super-Luminal Observer?

    Directory of Open Access Journals (Sweden)

    Rabounski D.

    2008-04-01

    Full Text Available This paper discusses the nature of a hypothetical super-luminal observer who, as well as a real (sub-light speed observer, perceives the world by light waves. This consideration is due to that fact that the theory of relativity permits different frames of reference, including light-like and super-luminal reference frames. In analogy with a blind pilot on board a supersonic jet aeroplane (or missile, perceived by blind people, it is concluded that the light barrier is observed in the framework of only the light signal exchange experiment.

  14. Dynamical evolution of galaxies in clusters

    International Nuclear Information System (INIS)

    Ostriker, J.P.

    1977-01-01

    In addition to the processes involved in the evolution of star clusters, there are three kinds of processes that are peculiar to, or far more important in, galaxy clusters than in star clusters: galaxy interactions with gas, high-velocity tidal interactions, and accretion and cannibalism. The latter is discussed at some length; analytical calculations for the apparent luminosity evolution of the first brightest galaxy and the apparent luminosity evolution of M 12 are described, along with the numerical simulation of cluster evolution. It appears that many of the notable features of centrally condensed clusters of galaxies, particularly the presence of very luminous but low-surface-brightness central cD systems, can be understood in terms of a straightforward dynamical theory of galactic cannibalism. It is possible to maintain the hypothesis that dynamical evolution gradually transforms Bautz--Morgan III clusters to type II systems or type I systems. 36 references, 5 figures

  15. Interpretation of data on the aggregate composition of typical chernozems under different land use by cluster and principal component analyses

    Science.gov (United States)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Lazarev, V. I.; Frid, A. S.

    2016-09-01

    Cluster analysis and principal component analysis (PCA) have been used for the interpretation of dry sieving data. Chernozems from the treatments of long-term field experiments with different land-use patterns— annually mowed steppe, continuous potato culture, permanent black fallow, and untilled fallow since 1998 after permanent black fallow—have been used. Analysis of dry sieving data by PCA has shown that the treatments of untilled fallow after black fallow and annually mowed steppe differ most in the series considered; the content of dry aggregates of 10-7 mm makes the largest contribution to the distribution of objects along the first principal component. This fraction has been sieved in water and analyzed by PCA. In contrast to dry sieving data, the wet sieving data showed the closest mathematical distance between the treatment of untilled fallow after black fallow and the undisturbed treatment of annually mowed steppe, while the untilled fallow after black fallow and the permanent black fallow were the most distant treatments. Thus, it may be suggested that the water stability of structure is first restored after the removal of destructive anthropogenic load. However, the restoration of the distribution of structural separates to the parameters characteristic of native soils is a significantly longer process.

  16. Luminance noise as a novel approach for measuring contrast sensitivity within the magnocellular and parvocellular pathways.

    Science.gov (United States)

    Hall, Cierra M; McAnany, J Jason

    2017-07-01

    This study evaluated the extent to which different types of luminance noise can be used to target selectively the inferred magnocellular (MC) and parvocellular (PC) visual pathways. Letter contrast sensitivity (CS) was measured for three visually normal subjects for letters of different size (0.8°-5.3°) under established paradigms intended to target the MC pathway (steady-pedestal paradigm) and PC pathway (pulsed-pedestal paradigm). Results obtained under these paradigms were compared to those obtained in asynchronous static noise (a field of unchanging luminance noise) and asynchronous dynamic noise (a field of randomly changing luminance noise). CS was measured for letters that were high- and low-pass filtered using a range of filter cutoffs to quantify the object frequency information (cycles per letter) mediating letter identification, which was used as an index of the pathway mediating CS. A follow-up experiment was performed to determine the range of letter duration over which MC and PC pathway CS can be targeted. Analysis of variance indicated that the object frequencies measured under the static noise and steady-pedestal paradigms did not differ significantly (p ≥ 0.065), but differed considerably from those measured under the dynamic noise (both p noise, and in dynamic noise. These data suggest that the spatiotemporal characteristics of noise can be manipulated to target the inferred MC (static noise) and PC (dynamic noise) pathways. The results also suggest that CS within these pathways can be measured at long stimulus durations, which has potential importance in the design of future clinical CS tests.

  17. Open source clustering software.

    Science.gov (United States)

    de Hoon, M J L; Imoto, S; Nolan, J; Miyano, S

    2004-06-12

    We have implemented k-means clustering, hierarchical clustering and self-organizing maps in a single multipurpose open-source library of C routines, callable from other C and C++ programs. Using this library, we have created an improved version of Michael Eisen's well-known Cluster program for Windows, Mac OS X and Linux/Unix. In addition, we generated a Python and a Perl interface to the C Clustering Library, thereby combining the flexibility of a scripting language with the speed of C. The C Clustering Library and the corresponding Python C extension module Pycluster were released under the Python License, while the Perl module Algorithm::Cluster was released under the Artistic License. The GUI code Cluster 3.0 for Windows, Macintosh and Linux/Unix, as well as the corresponding command-line program, were released under the same license as the original Cluster code. The complete source code is available at http://bonsai.ims.u-tokyo.ac.jp/mdehoon/software/cluster. Alternatively, Algorithm::Cluster can be downloaded from CPAN, while Pycluster is also available as part of the Biopython distribution.

  18. Cluster headache

    Science.gov (United States)

    Histamine headache; Headache - histamine; Migrainous neuralgia; Headache - cluster; Horton's headache; Vascular headache - cluster ... Doctors do not know exactly what causes cluster headaches. They ... (chemical in the body released during an allergic response) or ...

  19. THE UNUSUALLY LUMINOUS EXTRAGALACTIC NOVA SN 2010U

    International Nuclear Information System (INIS)

    Czekala, Ian; Berger, E.; Chornock, R.; Marion, G. H.; Margutti, R.; Challis, P.; Pastorello, A.; Botticella, M. T.; Ergon, M.; Sollerman, J.; Smartt, S.; Vinkó, J.; Wheeler, J. C.

    2013-01-01

    We present observations of the unusual optical transient SN 2010U, including spectra taken 1.03 days to 15.3 days after maximum light that identify it as a fast and luminous Fe II type nova. Our multi-band light curve traces the fast decline (t 2 = 3.5 ± 0.3 days) from maximum light (M V = –10.2 ± 0.1 mag), placing SN 2010U in the top 0.5% of the most luminous novae ever observed. We find typical ejecta velocities of ≈1100 km s –1 and that SN 2010U shares many spectral and photometric characteristics with two other fast and luminous Fe II type novae, including Nova LMC 1991 and M31N-2007-11d. For the extreme luminosity of this nova, the maximum magnitude versus rate of decline relationship indicates a massive white dwarf (WD) progenitor with a low pre-outburst accretion rate. However, this prediction is in conflict with emerging theories of nova populations, which predict that luminous novae from massive WDs should preferentially exhibit an alternate spectral type (He/N) near maximum light.

  20. Profile of a Growing Urban School: The Lumin Experience

    Science.gov (United States)

    Ford, Terry

    2015-01-01

    This fairytale-come-true began with an idealistic public school teacher just out of college who lived in the neighborhood of her students. In stages, working with a community organizing group consisting mainly of concerned parents, Terry Ford founded what is now called Lumin Education, a network of campuses serving more than six hundred children…

  1. SN 2010U: A LUMINOUS NOVA IN NGC 4214

    International Nuclear Information System (INIS)

    Humphreys, Roberta M.; Helton, L. Andrew; Prieto, Jose L.; Rosenfield, Philip; Williams, Benjamin; Murphy, Jeremiah; Dalcanton, Julianne; Gilbert, Karoline; Kochanek, Christopher S.; Stanek, K. Z.; Khan, Rubab; Szczygiel, Dorota; Mogren, Karen; Fesen, Robert A.; Milisavljevic, Dan

    2010-01-01

    The luminosity, light curve, post-maximum spectrum, and lack of a progenitor on deep pre-outburst images suggest that SN 2010U was a luminous, fast nova. Its outburst magnitude is consistent with that for a fast nova using the maximum magnitude-rate of decline relationship for classical novae.

  2. Might dark matter not be concentric with luminous matter

    International Nuclear Information System (INIS)

    Xu Chongming; Lu Tan.

    1986-12-01

    In this paper, an idea on dark matter nonconcentric with luminous matter is proposed. This case could influence the rotation curve of galaxy differently in its different direction. Recently, Rubin and Ford's observation on rotation curve of Hickson 88a has been explained by means of the idea. Some possible observational predictions have also been given. (author)

  3. Luminance compensation for AMOLED displays using integrated MIS sensors

    Science.gov (United States)

    Vygranenko, Yuri; Fernandes, Miguel; Louro, Paula; Vieira, Manuela

    2017-05-01

    Active-matrix organic light-emitting diodes (AMOLEDs) are ideal for future TV applications due to their ability to faithfully reproduce real images. However, pixel luminance can be affected by instability of driver TFTs and aging effect in OLEDs. This paper reports on a pixel driver utilizing a metal-insulator-semiconductor (MIS) sensor for luminance control of the OLED element. In the proposed pixel architecture for bottom-emission AMOLEDs, the embedded MIS sensor shares the same layer stack with back-channel etched a Si:H TFTs to maintain the fabrication simplicity. The pixel design for a large-area HD display is presented. The external electronics performs image processing to modify incoming video using correction parameters for each pixel in the backplane, and also sensor data processing to update the correction parameters. The luminance adjusting algorithm is based on realistic models for pixel circuit elements to predict the relation between the programming voltage and OLED luminance. SPICE modeling of the sensing part of the backplane is performed to demonstrate its feasibility. Details on the pixel circuit functionality including the sensing and programming operations are also discussed.

  4. Mechanical feedback in the molecular ISM of luminous IR galaxies

    NARCIS (Netherlands)

    Loenen, A. F.; Spaans, M.; Baan, W. A.; Meijerink, R.

    Aims. Molecular emission lines originating in the nuclei of luminous infra-red galaxies are used to determine the physical properties of the nuclear ISM in these systems. Methods. A large observational database of molecular emission lines is compared with model predictions that include heating by UV

  5. Astronomy. ASASSN-15lh: A highly super-luminous supernova.

    Science.gov (United States)

    Dong, Subo; Shappee, B J; Prieto, J L; Jha, S W; Stanek, K Z; Holoien, T W-S; Kochanek, C S; Thompson, T A; Morrell, N; Thompson, I B; Basu, U; Beacom, J F; Bersier, D; Brimacombe, J; Brown, J S; Bufano, F; Chen, Ping; Conseil, E; Danilet, A B; Falco, E; Grupe, D; Kiyota, S; Masi, G; Nicholls, B; Olivares E, F; Pignata, G; Pojmanski, G; Simonian, G V; Szczygiel, D M; Woźniak, P R

    2016-01-15

    We report the discovery of ASASSN-15lh (SN 2015L), which we interpret as the most luminous supernova yet found. At redshift z = 0.2326, ASASSN-15lh reached an absolute magnitude of Mu ,AB = -23.5 ± 0.1 and bolometric luminosity Lbol = (2.2 ± 0.2) × 10(45) ergs s(-1), which is more than twice as luminous as any previously known supernova. It has several major features characteristic of the hydrogen-poor super-luminous supernovae (SLSNe-I), whose energy sources and progenitors are currently poorly understood. In contrast to most previously known SLSNe-I that reside in star-forming dwarf galaxies, ASASSN-15lh appears to be hosted by a luminous galaxy (MK ≈ -25.5) with little star formation. In the 4 months since first detection, ASASSN-15lh radiated (1.1 ± 0.2) × 10(52) ergs, challenging the magnetar model for its engine. Copyright © 2016, American Association for the Advancement of Science.

  6. Gastric luminal epidermal growth factor is affected by diet | Iputo ...

    African Journals Online (AJOL)

    Objective. Diet is an area of major interest to those investigating the causes of cancer of the oesophagus in the Transkei. This study looked at the associations between intragastric epidermal growth factor level, diet and intragastric pH. Setting and subjects. A dietary survey was co-ordinated with studies of gastric luminal ...

  7. Vocal Fold Epithelial Response to Luminal Osmotic Perturbation

    Science.gov (United States)

    Sivasankar, Mahalakshmi; Fisher, Kimberly V.

    2007-01-01

    Purpose: Dry-air challenges increase the osmolarity of fluid lining the luminal surface of the proximal airway. The homeostasis of surface fluid is thought to be essential for voice production and laryngeal defense. Therefore, the authors hypothesized that viable vocal fold epithelium would generate a water flux to reduce an osmotic challenge (150…

  8. The predetermination of the luminance in tunnel entrances at day.

    NARCIS (Netherlands)

    Schreuder, D.A. & Oud, H.J.C.

    1988-01-01

    In tunnel lighting practice, only the scatter in the eye, in the windscreen of the car, and in the atmosphere need to be taken into account. For all practical day- time conditions, the required luminance in any portion of the tunnel can be assessed as being a constant fraction of this sum-

  9. Relationship between luminous fish and symbiosis. I. Comparative studies of lipopolysaccharides isolated from symbiotic luminous bacteria of the luminous marine fish, Physiculus japonicus.

    Science.gov (United States)

    Kuwae, T; Andoh, M; Fukasawa, S; Kurata, M

    1983-01-01

    In order to investigate the relationship between host and symbiosis in the luminous marine fish, Physiculus japonicus, the bacterial lipopolysaccharides (LPS) of symbiotic luminous bacteria were compared serologically and electrophoretically. Five symbiotic luminous bacteria (PJ strains) were separately isolated from five individuals of this fish species caught at three points, off the coasts of Chiba, Nakaminato, and Oharai. LPS preparations were made from these bacteria by Westphal's phenol-water method and highly purified by repeated ultracentrifugation. These LPSs contained little or no 2-keto-3-deoxyoctonate and had powerful mitogenic activity. In sodium dodecylsulfate polyacrylamide gel electrophoresis, these PJ-1 to -5 LPSs were separated by their electrophoretic patterns into three groups; the first group included PJ-1 and PJ-4, the second group PJ-2 and PJ-3, and the third group PJ-5 alone. The results agreed with those of the double immunodiffusion test; precipitin lines completely coalesced within each group but not with other groups. In immunoelectrophoresis, one precipitin line was observed between anti PJ-2 LPS serum and PJ-5 LPS but the electrophoretic mobility of PJ-5 LPS was clearly different from that of the PJ-2 LPS group. Furthermore, in a 50% inhibition test with PJ-2 LPS by the passive hemolysis system, the doses of PJ-2 LPS, PJ-3 LPS, and PJ-5 LPS required for 50% inhibition (ID50) in this system were 0.25, 0.25, and 21.6 micrograms/ml for each alkali-treated LPS, respectively, and the ID50's of both PJ-1 LPS and PJ-4 LPS were above 1,000 micrograms/ml. These results indicate that PJ-5 LPS has an antigenic determinant partially in common with LPS from the PJ-2 group but not with LPS from the PJ-1 group and that the symbiotic luminous bacterium PJ-5 is more closely related to the PJ-2 group than to the PJ-1 group. These results show that the species Physiculus japonicus is symbiotically associated with at least three immunologically different

  10. Reproducibility of airway luminal size in asthma measured by HRCT.

    Science.gov (United States)

    Brown, Robert H; Henderson, Robert J; Sugar, Elizabeth A; Holbrook, Janet T; Wise, Robert A

    2017-10-01

    Brown RH, Henderson RJ, Sugar EA, Holbrook JT, Wise RA, on behalf of the American Lung Association Airways Clinical Research Centers. Reproducibility of airway luminal size in asthma measured by HRCT. J Appl Physiol 123: 876-883, 2017. First published July 13, 2017; doi:10.1152/japplphysiol.00307.2017.-High-resolution CT (HRCT) is a well-established imaging technology used to measure lung and airway morphology in vivo. However, there is a surprising lack of studies examining HRCT reproducibility. The CPAP Trial was a multicenter, randomized, three-parallel-arm, sham-controlled 12-wk clinical trial to assess the use of a nocturnal continuous positive airway pressure (CPAP) device on airway reactivity to methacholine. The lack of a treatment effect of CPAP on clinical or HRCT measures provided an opportunity for the current analysis. We assessed the reproducibility of HRCT imaging over 12 wk. Intraclass correlation coefficients (ICCs) were calculated for individual airway segments, individual lung lobes, both lungs, and air trapping. The ICC [95% confidence interval (CI)] for airway luminal size at total lung capacity ranged from 0.95 (0.91, 0.97) to 0.47 (0.27, 0.69). The ICC (95% CI) for airway luminal size at functional residual capacity ranged from 0.91 (0.85, 0.95) to 0.32 (0.11, 0.65). The ICC measurements for airway distensibility index and wall thickness were lower, ranging from poor (0.08) to moderate (0.63) agreement. The ICC for air trapping at functional residual capacity was 0.89 (0.81, 0.94) and varied only modestly by lobe from 0.76 (0.61, 0.87) to 0.95 (0.92, 0.97). In stable well-controlled asthmatic subjects, it is possible to reproducibly image unstimulated airway luminal areas over time, by region, and by size at total lung capacity throughout the lungs. Therefore, any changes in luminal size on repeat CT imaging are more likely due to changes in disease state and less likely due to normal variability. NEW & NOTEWORTHY There is a surprising lack

  11. VizieR Online Data Catalog: Absorption velocities for 21 super-luminous SNe Ic (Liu+, 2017)

    Science.gov (United States)

    Liu, Y.-Q.; Modjaz, M.; Bianco, F. B.

    2018-04-01

    We have collected the spectra of all available super-luminous supernovae (SLSNe) Ic that have a date of maximum light published before April of 2016. These SLSNe Ic were mainly discovered and observed by the All-Sky Automated Survey for Supernovae (ASAS-SN), the Catalina Real-Time Transient Survey, the Dark Energy Survey (DES), the Hubble Space Telescope Cluster Supernova Survey, the Pan-STARRS1 Medium Deep Survey (PS1), the Public ESO Spectroscopic Survey of Transient Objects (PESSTO), the Intermediate Palomar Transient Factory (iPTF) as well as the Palomar Transient Factory (PTF), and the Supernova Legacy Survey (SNLS). See table 1. (2 data files).

  12. Dynamic regulation of gastric surface pH by luminal pH

    OpenAIRE

    Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

    1999-01-01

    In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 μm adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intra...

  13. SPECTRAL AND SPATIAL SELECTIVITY OF LUMINANCE VISION IN REEF FISH

    Directory of Open Access Journals (Sweden)

    Ulrike E Siebeck

    2014-09-01

    Full Text Available Luminance vision has high spatial resolution and is used for form vision and texture discrimination. In humans, birds and bees luminance channel is spectrally selective – it depends on the signals of the long-wavelength sensitive photoreceptors (bees or on the sum of long- and middle- wavelength sensitive cones (humans, but not on the signal of the short-wavelength sensitive (blue photoreceptors. The reasons of such selectivity are not fully understood. The aim of this study is to reveal the inputs of cone signals to high resolution luminance vision in reef fish. 16 freshly caught damselfish, Pomacentrus amboinensis, were trained to discriminate stimuli differing either in their colour or in their fine patterns (stripes vs. cheques. Three colours (‘bright green’, ‘dark green’ and ‘blue’ were used to create two sets of colour and two sets of pattern stimuli. The ‘bright green’ and ‘dark green’ were similar in their chromatic properties for fish, but differed in their lightness; the ‘dark green’ differed from ‘blue’ in the signal for the blue cone, but yielded similar signals in the long-wavelength and middle-wavelength cones. Fish easily learned to discriminate ‘bright green’ from ‘dark green’ and ‘dark green’ from ‘blue’ stimuli. Fish also could discriminate the fine patterns created from ‘dark green’ and ‘bright green’. However, fish failed to discriminate fine patterns created from ‘blue’ and ‘dark green’ colours, i.e. the colours that provided contrast for the blue-sensitive photoreceptor, but not for the long-wavelength sensitive one. High resolution luminance vision in damselfish, Pomacentrus amboinensis, does not have input from the blue-sensitive cone, which may indicate that the spectral selectivity of luminance channel is a general feature of visual processing in both aquatic and terrestrial animals.

  14. Luminous flux improvement of xenon fluorescent lamps by applying synchronized high-voltage pulse to the auxiliary external electrode

    Energy Technology Data Exchange (ETDEWEB)

    Motomura, Hideki; Oka, Kojiro; Sogabe, Toru; Jinno, Masafumi, E-mail: hmoto@mayu.ee.ehime-u.ac.jp [Department of Electrical and Electronic Engineering, Ehime University 3 Bunkyo-cho, Matsuyama, Ehime 790-8577 (Japan)

    2011-06-08

    As the environmental awareness of people becomes stronger, the demand for mercury-free light sources also becomes stronger. The authors have been developing cold cathode fluorescent lamps in which xenon gas is filled as an ultraviolet radiator instead of mercury. Previously the authors reported the luminous flux enhancement method using a grounded auxiliary external electrode (AEE). In this paper, in order to improve the luminous flux much more, a positive voltage pulse which was synchronized to the main driving negative voltage pulse was applied to the AEE. As a result, the maximum input power increased under which the positive column did not constrict and the luminous flux improved by 70% at the xenon filling pressure of 6.7 kPa. It is proved that the positive voltage pulse application to the AEE with the amplitude of more than 2 kV expands the positive column in the radial direction. It is attributed to the phenomenon that the residual ions and electrons, which are generated by dielectric barrier discharge between the AEE and the anode during the falling edge of the negative pulse to the cathode, spread the discharge path from the anode towards the AEE during the cold cathode discharge mode. By increasing the xenon filling pressure, luminous efficacy was improved to 25 lm W{sup -1}.

  15. The birth of star clusters

    CERN Document Server

    2018-01-01

    All stars are born in groups. The origin of these groups has long been a key question in astronomy, one that interests researchers in star formation, the interstellar medium, and cosmology. This volume summarizes current progress in the field, and includes contributions from both theorists and observers. Star clusters appear with a wide range of properties, and are born in a variety of physical conditions. Yet the key question remains: How do diffuse clouds of gas condense into the collections of luminous objects we call stars? This book will benefit graduate students, newcomers to the field, and also experienced scientists seeking a convenient reference.

  16. Effects of Irradiation on bacterial atp luminous intensity of cooled pork and chicken

    International Nuclear Information System (INIS)

    Ju Hua

    2010-01-01

    The effect of irradiation on cooled pork and chicken was detected with ATP luminous intensity method. The influences of other factors to ATP luminous intensity were also discussed. There was positive correlation between ATP standard concentration and ATP luminous intensity, and negative correlation between irradiation dosage and ATP luminous intensity. The trend of ATP luminous intensity of cooled pork and chicken after irradiation was inverse S, and the maximum ATP luminous intensity appeared at 6.0 kGy, and minimum at 4.0 and 8.0 kGy. Sterilized water and sterilized pork had no interference to ATP luminous intensity of the samples. There was significant positive correlation between E. coli 10003 concentration and ATP luminous intensity, the coefficient correlation was 0.9437. (authors)

  17. Interfacial oxygen under TiO2 supported Au clusters revealed by a genetic algorithm search

    DEFF Research Database (Denmark)

    Vilhelmsen, Lasse Baarvig; Hammer, B.

    2013-01-01

    We present a density functional theory study of the oxidation of 1D periodic rods supported along the [001] direction on the rutile TiO2(110) surface. The study shows evidence for an oxidation of the interface between the supported Au and the TiO2 crystal. The added O atoms adsorb at the 5f......-Ti atoms in the through under the Au rod and are stabilized by charge transfer from the nearest Au atoms. Despite an extensive search, we find no low energy barrier pathways for CO oxidation involving CO adsorbed on Au and O at the perimeter of the Au/TiO2 interface. This is in part attributed the weak...

  18. File list: His.Brs.10.AllAg.Luminal_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Brs.10.AllAg.Luminal_cells mm9 Histone Breast Luminal cells SRX213395,SRX213418...,SRX213416 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Brs.10.AllAg.Luminal_cells.bed ...

  19. File list: ALL.Brs.10.AllAg.Luminal_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Brs.10.AllAg.Luminal_cells mm9 All antigens Breast Luminal cells SRX213395,SRX2...13418,SRX213398,SRX213416 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Brs.10.AllAg.Luminal_cells.bed ...

  20. File list: ALL.Brs.50.AllAg.Luminal_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Brs.50.AllAg.Luminal_cells mm9 All antigens Breast Luminal cells SRX213395,SRX2...13418,SRX213398,SRX213416 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Brs.50.AllAg.Luminal_cells.bed ...

  1. File list: His.Brs.05.AllAg.Luminal_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Brs.05.AllAg.Luminal_cells mm9 Histone Breast Luminal cells SRX213395,SRX213418...,SRX213416 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Brs.05.AllAg.Luminal_cells.bed ...

  2. File list: His.Brs.50.AllAg.Luminal_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Brs.50.AllAg.Luminal_cells mm9 Histone Breast Luminal cells SRX213395,SRX213418...,SRX213416 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Brs.50.AllAg.Luminal_cells.bed ...

  3. File list: ALL.Brs.20.AllAg.Luminal_cells [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Brs.20.AllAg.Luminal_cells mm9 All antigens Breast Luminal cells SRX213395,SRX2...13418,SRX213398,SRX213416 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Brs.20.AllAg.Luminal_cells.bed ...

  4. Radiation exposure to dial painters from 3H luminous paint industry

    International Nuclear Information System (INIS)

    Sawant, J.V.

    1992-01-01

    Tritium is used as the active component in self-luminous paint. The paper describes in-vitro solubilisation study of luminous paint in blood serum. Besides urine samples of luminous paint workers and air samples of two watch factories were analysed for 3 H. The results of these analysis are also presented. (author). 8 refs., 4 figs., 4 tabs

  5. Conjunctions of colour, luminance and orientation: the role of colour and luminance contrast on saliency and proximity grouping in texture segregation.

    Science.gov (United States)

    Leonards, U; Singer, W

    2000-01-01

    To examine whether perceptual grouping on the basis of orientation can be performed simultaneously with or only subsequently to grouping according to colour or luminance, we tested whether subjects are able to segregate arrays of texture elements that differ from surrounding elements by conjunctions of either (i) colour and orientation, or (ii) luminance contrast and orientation, or (iii) luminance contrast polarity and orientation. Subjects were able to use conjunctions between luminance and orientation for segregation but not conjunctions between colour or contrast polarity and orientation. Our results suggest that (i) in agreement with earlier findings, there seem to exist no specific conjunction detectors for colour and orientation or contrast polarity and orientation, and (ii) when orientation defined textures are to be distinguished by virtue of differences in luminance, colour, or contrast polarity, luminance provides a much stronger cue than colour or contrast polarity for saliency-based orientation grouping.

  6. When Clusters become Networks

    NARCIS (Netherlands)

    S.M.W. Phlippen (Sandra); G.A. van der Knaap (Bert)

    2007-01-01

    textabstractPolicy makers spend large amounts of public resources on the foundation of science parks and other forms of geographically clustered business activities, in order to stimulate regional innovation. Underlying the relation between clusters and innovation is the assumption that co-located

  7. Cluster growth kinetics

    International Nuclear Information System (INIS)

    Dubovik, V.M.; Gal'perin, A.G.; Rikhvitskij, V.S.; Lushnikov, A.A.

    2000-01-01

    Processes of some traffic blocking coming into existence are considered as probabilistic ones. We study analytic solutions for models for the dynamics of both cluster growth and cluster growth with fragmentation in the systems of finite number of objects. Assuming rates constancy of both coalescence and fragmentation, the models under consideration are linear on the probability functions

  8. Spatiotemporal Characteristics for the Depth from Luminance Contrast

    Directory of Open Access Journals (Sweden)

    Kazuya Matsubara

    2011-05-01

    Full Text Available Images with higher luminance contrast tend to be perceived closer in depth. To investigate a spatiotemporal characteristic of this effect, we evaluated subjective depth of a test stimulus with various spatial and temporal frequencies. For the purpose, the depth of a reference stimulus was matched to that of the test stimulus by changing the binocular disparity. The results showed that the test stimulus was perceived closer with higher luminance contrast for all conditions. Contrast efficiency was obtained from the contrast that provided the subjective depth for each spatiotemporal frequency. The shape of the contrast efficiency function was spatially low-pass and temporally band-pass. This characteristic is different from the one measure for a detection task. This suggests that only subset of contrast signals are used for depth from contrast.

  9. Development and construction of a programmable generator of luminous impulses

    International Nuclear Information System (INIS)

    Sahuc, P.

    1989-01-01

    The design and construction of an impulse generator, for light waves, designed to control the characteristics of a scintillator. In these detectors, a particle gives rise to the emission of a luminous signal, which must be transformed in an electrical signal. In the present work, photomultipliers are used as luminous-electrical signal converters. The principles of operation of a scintillator, of a scintillator connected with a photodiode, and of a scintillator connected with a photomultiplier are reviewed. The analysis of the performance and of the possibilies offered by the usual generators of light, show that more suitable solutions are required. The characteristics of the electroluminescent diodes, their performances, concerning light emission and power, are investigated. The principles, the operating conditions and the performances of a generator of light, applying electroluminescent diodes, are examined. The construction and the results obtained with a prototype are presented [fr

  10. Virulence of luminous vibrios to Artemia franciscana nauplii.

    Science.gov (United States)

    Soto-Rodriguez, S A; Roque, A; Lizarraga-Partida, M L; Guerra-Flores, A L; Gomez-Gill, B

    2003-02-27

    From healthy and diseased penaeid shrimp from Asia and the Americas, 25 luminous and 2 non-luminous bacterial strains were isolated, and 14 were phenotypically identified as Vibrio harveyi; 9 isolates produced significant mortalities (45 to 80%) in Artemia franciscana nauplii at inoculation densities of 10(5) to 10(6) CFU ml(-1) compared to the controls (unchallenged nauplii). The maximum number of bacteria ingested (bioencapsulated) by the Artemia nauplii varied from less than 10 to 10(3) CFU nauplius(-1) and no significant relationship was observed between the density of bacteria inoculated, the amount of bacteria ingested, and naupliar mortality. Significant correlations were obtained between naupliar mortality and production of proteases, phospholipases or siderophores, but not between mortality and lipase production, gelatinase production, hydrophobicity or hemolytic activity. The results suggest that virulence of the strains tested was more related to the production of particular exoenzymes than to the measured colonization factors.

  11. Geometry of illumination, luminance contrast, and gloss perception.

    Science.gov (United States)

    Leloup, Frédéric B; Pointer, Michael R; Dutré, Philip; Hanselaer, Peter

    2010-09-01

    The influence of both the geometry of illumination and luminance contrast on gloss perception has been examined using the method of paired comparison. Six achromatic glass samples having different lightness were illuminated by two light sources. Only one of these light sources was visible in reflection by the observer. By separate adjustment of the intensity of both light sources, the luminance of both the reflected image and the adjacent off-specular surroundings could be individually varied. It was found that visual gloss appraisal did not correlate with instrumentally measured specular gloss; however, psychometric contrast seemed to be a much better correlate. It has become clear that not only the sample surface characteristics determine gloss perception: the illumination geometry could be an even more important factor.

  12. Awareness of Central Luminance Edge is Crucial for the Craik-O'Brien-Cornsweet Effect.

    Science.gov (United States)

    Masuda, Ayako; Watanabe, Junji; Terao, Masahiko; Watanabe, Masataka; Yagi, Akihiro; Maruya, Kazushi

    2011-01-01

    The Craik-O'Brien-Cornsweet (COC) effect demonstrates that perceived lightness depends not only on the retinal input at corresponding visual areas but also on distal retinal inputs. In the COC effect, the central edge of an opposing pair of luminance gradients (COC edge) makes adjoining regions with identical luminance appear to be different. To investigate the underlying mechanisms of the effect, we examined whether the subjective awareness of the COC edge is necessary for the generation of the effect. We manipulated the visibility of the COC edge using visual backward masking and continuous flash suppression while monitoring subjective reports regarding online percepts and aftereffects of adaptation. Psychophysical results showed that the online percept of the COC effect nearly vanishes in conditions where the COC edge is rendered invisible. On the other hand, the results of adaptation experiments showed that the COC edge is still processed at the early stage even under the perceptual suppression. These results suggest that processing of the COC edge at the early stage is not sufficient for generating the COC effect, and that subjective awareness of the COC edge is necessary.

  13. An evaluation of organic light emitting diode monitors for medical applications: great timing, but luminance artifacts.

    Science.gov (United States)

    Elze, Tobias; Taylor, Christopher; Bex, Peter J

    2013-09-01

    In contrast to the dominant medical liquid crystal display (LCD) technology, organic light-emitting diode (OLED) monitors control the display luminance via separate light-emitting diodes for each pixel and are therefore supposed to overcome many previously documented temporal artifacts of medical LCDs. We assessed the temporal and luminance characteristics of the only currently available OLED monitor designed for use in the medical treatment field (SONY PVM2551MD) and checked the authors' main findings with another SONY OLED device (PVM2541). Temporal properties of the photometric output were measured with an optical transient recorder. Luminances of the three color primaries and white for all 256 digital driving levels (DDLs) were measured with a spectroradiometer. Between the luminances of neighboring DDLs, just noticeable differences were calculated according to a perceptual model developed for medical displays. Luminances of full screen (FS) stimuli were compared to luminances of smaller stimuli with identical DDLs. All measured luminance transition times were below 300 μs. Luminances were independent of the luminance in the preceding frame. However, for the single color primaries, up to 50.5% of the luminances of neighboring DDLs were not perceptually distinguishable. If two color primaries were active simultaneously, between 36.7% and 55.1% of neighboring luminances for increasing DDLs of the third primary were even decreasing. Moreover, luminance saturation effects were observed when too many pixels were active simultaneously. This effect was strongest for white; a small white patch was close to 400 cd/m(2), but in FS the luminance of white saturated at 162 cd/m(2). Due to different saturation levels, the luminance of FS green and FS yellow could exceed the luminance of FS white for identical DDLs. The OLED temporal characteristics are excellent and superior to those of LCDs. However, the OLEDs revealed severe perceptually relevant artifacts with

  14. A Hubble Space Telescope Survey of the Disk Cluster Population of M31. II. Advanced Camera for Surveys Pointings

    Science.gov (United States)

    Krienke, O. K.; Hodge, P. W.

    2008-01-01

    This paper reports on a survey of star clusters in M31 based on archival images from the Hubble Space Telescope. Paper I reported results from images obtained with the Wide Field Planetary Camera 2 (WFPC2) and this paper reports results from the Advanced Camera for Surveys (ACS). The ACS survey has yielded a total of 339 star clusters, 52 of which—mostly globular clusters—were found to have been cataloged previously. As for the previous survey, the luminosity function of the clusters drops steeply for absolute magnitudes fainter than MV = -3 the implied cluster mass function has a turnover for masses less than a few hundred solar masses. The color-integrated magnitude diagram of clusters shows three significant features: (1) a group of very red, luminous objects: the globular clusters, (2) a wide range in color for the fainter clusters, representing a considerable range in age and reddening, and (3) a maximum density of clusters centered approximately at V = 21, B - V = 0.30, V - I = 0.50, where there are intermediate-age, intermediate-mass clusters with ages close to 500 million years and masses of about 2000 solar masses. We give a brief qualitative interpretation of the distribution of clusters in the CMDs in terms of their formation and destruction rates. Based on observations with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for research in astronomy, Inc., under NASA contract NAS 5-26555.

  15. Damage detection methodology under variable load conditions based on strain field pattern recognition using FBGs, nonlinear principal component analysis, and clustering techniques

    Science.gov (United States)

    Sierra-Pérez, Julián; Torres-Arredondo, M.-A.; Alvarez-Montoya, Joham

    2018-01-01

    Structural health monitoring consists of using sensors integrated within structures together with algorithms to perform load monitoring, damage detection, damage location, damage size and severity, and prognosis. One possibility is to use strain sensors to infer structural integrity by comparing patterns in the strain field between the pristine and damaged conditions. In previous works, the authors have demonstrated that it is possible to detect small defects based on strain field pattern recognition by using robust machine learning techniques. They have focused on methodologies based on principal component analysis (PCA) and on the development of several unfolding and standardization techniques, which allow dealing with multiple load conditions. However, before a real implementation of this approach in engineering structures, changes in the strain field due to conditions different from damage occurrence need to be isolated. Since load conditions may vary in most engineering structures and promote significant changes in the strain field, it is necessary to implement novel techniques for uncoupling such changes from those produced by damage occurrence. A damage detection methodology based on optimal baseline selection (OBS) by means of clustering techniques is presented. The methodology includes the use of hierarchical nonlinear PCA as a nonlinear modeling technique in conjunction with Q and nonlinear-T 2 damage indices. The methodology is experimentally validated using strain measurements obtained by 32 fiber Bragg grating sensors bonded to an aluminum beam under dynamic bending loads and simultaneously submitted to variations in its pitch angle. The results demonstrated the capability of the methodology for clustering data according to 13 different load conditions (pitch angles), performing the OBS and detecting six different damages induced in a cumulative way. The proposed methodology showed a true positive rate of 100% and a false positive rate of 1.28% for a

  16. Selected luminal mucosal complications of adult celiac disease

    OpenAIRE

    Freeman, Hugh

    2009-01-01

    Hugh J FreemanDepartment of Medicine (Gastroenterology), University of British Columbia, Vancouver, BC, CanadaAbstract: Celiac disease is a gluten-dependent intestinal disorder that appears to be associated with several clinical conditions. Some involve the luminal mucosa of the stomach and intestinal tract and may, occasionally, complicate the course of celiac disease. Collagenous colitis has been associated with celiac disease and may lead to chronic diarrhea. Conversely, some of t...

  17. Enigmatic sub-luminous accreting neutron stars in our Galaxy

    NARCIS (Netherlands)

    Wijnands, R.

    2008-01-01

    During the last few years a class of enigmatic sub-luminous accreting neutron stars has been found in our Galaxy. They have peak X-ray luminosities (2-10 keV) of a few times 10(34) erg s(−1) to a few times 10(35) erg s(−1), and both persistent and transient sources have been found. I present a short

  18. Dynamic encoding of natural luminance sequences by LGN bursts.

    Directory of Open Access Journals (Sweden)

    Nicholas A Lesica

    2006-07-01

    Full Text Available In the lateral geniculate nucleus (LGN of the thalamus, visual stimulation produces two distinct types of responses known as tonic and burst. Due to the dynamics of the T-type Ca(2+ channels involved in burst generation, the type of response evoked by a particular stimulus depends on the resting membrane potential, which is controlled by a network of modulatory connections from other brain areas. In this study, we use simulated responses to natural scene movies to describe how modulatory and stimulus-driven changes in LGN membrane potential interact to determine the luminance sequences that trigger burst responses. We find that at low resting potentials, when the T channels are de-inactivated and bursts are relatively frequent, an excitatory stimulus transient alone is sufficient to evoke a burst. However, to evoke a burst at high resting potentials, when the T channels are inactivated and bursts are relatively rare, prolonged inhibitory stimulation followed by an excitatory transient is required. We also observe evidence of these effects in vivo, where analysis of experimental recordings demonstrates that the luminance sequences that trigger bursts can vary dramatically with the overall burst percentage of the response. To characterize the functional consequences of the effects of resting potential on burst generation, we simulate LGN responses to different luminance sequences at a range of resting potentials with and without a mechanism for generating bursts. Using analysis based on signal detection theory, we show that bursts enhance detection of specific luminance sequences, ranging from the onset of excitatory sequences at low resting potentials to the offset of inhibitory sequences at high resting potentials. These results suggest a dynamic role for burst responses during visual processing that may change according to behavioral state.

  19. Method and apparatus for generating highly luminous flame

    Energy Technology Data Exchange (ETDEWEB)

    Gitman, G.M.

    1992-05-12

    A combustion process and apparatus are provided for generating a variable high temperature, highly luminous flame with low NOx emission by burning gaseous and liquid materials with oxygen and air. More particularly, the invention provides a process in which there is initial control of fuel, oxygen, and air flows and the delivery of the oxidizers to a burner as two oxidizing gases having different oxygen concentrations (for example, pure oxygen and air, or oxygen and oxygen-enriched air). A first oxidizing gas containing a high oxygen concentration is injected as a stream into the central zone of a combustion tunnel or chamber, and part of the fuel (preferably the major part) is injected into the central pyrolysis zone to mix with the first oxidizing gas to create a highly luminous high-temperature flame core containing microparticles of carbon of the proper size for maximum luminosity and high temperature, and a relatively small amount of hydrocarbon radicals. In addition, part of the fuel (preferably the minor part) is injected in a plurality of streams about the flame core to mix with a second oxidizing gas (containing a lower oxygen concentration than the first oxidizing gas) and injecting the second oxidizing mixture about the flame core and the minor fuel flow to mix with the minor fuel flow. This creates a plurality of fuel-lean (oxygen-rich) flames which are directed toward the luminous flame core to form a final flame pattern having high temperature, high luminosity, and low NOx content. 6 figs.

  20. The Role of Luminance and Chromaticity on Symmetry Detection

    Directory of Open Access Journals (Sweden)

    Chia-Ching Wu

    2011-05-01

    Full Text Available We investigated the effect of luminance and chromaticity on symmetry detection with the noise masking paradigm. In each trial, a random dot noise mask was presented in both intervals. A symmetric target was randomly presented in one interval while a random dot control was presented in the other. The orientation of the symmetric axis of the target was either 45°or −45° diagonal. The task of the observer was to determine which interval contained a symmetric target. The dots in both the target and the mask was painted with 1 to 4 colors selected from white, black, red, green, blue and yellow. We measured the target density threshold at various noise densities. Our results showed that when the number of the colors in the images was equal, the thresholds were lower in the luminance conditions than in the chromaticity conditions. In addition, the thresholds decreased with the increment of the number of the colors in the images. This suggests that (1 the luminance symmetry detection mechanism is more sensitive than chromaticity one and (2 that, contrasted to the prediction of an uncertainty model, the diversity in color facilitates symmetry detection.

  1. Wavelength and ambient luminance dependence of laser eye dazzle.

    Science.gov (United States)

    Williamson, Craig A; McLin, Leon N; Rickman, J Michael; Manka, Michael A; Garcia, Paul V; Kinerk, Wesley T; Smith, Peter A

    2017-10-10

    A series of experiments has been conducted to quantify the effects of laser wavelength and ambient luminance on the severity of laser eye dazzle experienced by human subjects. Eight laser wavelengths in the visible spectrum were used (458-647 nm) across a wide range of ambient luminance conditions (0.1-10,000  cd·m -2 ). Subjects were exposed to laser irradiance levels up to 600  μW·cm -2 and were asked to recognize the orientation of optotypes at varying eccentricities up to 31.6 deg of visual angle from the laser axis. More than 40,000 data points were collected from 14 subjects (ages 23-64), and these were consolidated into a series of obscuration angles for comparison to a theoretical model of laser eye dazzle. Scaling functions were derived to allow the model to predict the effects of laser dazzle on vision more accurately by including the effects of ambient luminance and laser wavelength. The updated model provides an improved match to observed laser eye dazzle effects across the full range of conditions assessed. The resulting model will find use in a variety of laser safety applications, including the estimation of maximum dazzle exposure and nominal ocular dazzle distance values.

  2. Relationships between luminance and visual acuity in the rhesus monkey

    Science.gov (United States)

    Cavonius, C. R.; Robbins, D. O.

    1973-01-01

    1. The ability of rhesus monkeys to detect the gap in Landolt ring test-objects that were presented against background luminances between 5 × 10-5 cd/m2 and 5 × 103 cd/m2 was compared with similar human data. 2. At high luminance-levels the acuity of human observers is slightly better than that of rhesus, but rhesus have better acuity at scotopic luminance-levels. Both species have distinct photopic and scotopic acuity functions that cross at 6 × 10-3 cd/m2. 3. The threshold for light detection is estimated to be the same for both species when specified in quanta incident on the retina. 4. It is concluded that the receptor and neural mechanisms that mediate visual-acuity function similarly in rhesus and man, and that the differences in acuity that were measured in the two species may be attributed to optical rather than to physiological factors. PMID:4199366

  3. Cluster management.

    Science.gov (United States)

    Katz, R

    1992-11-01

    Cluster management is a management model that fosters decentralization of management, develops leadership potential of staff, and creates ownership of unit-based goals. Unlike shared governance models, there is no formal structure created by committees and it is less threatening for managers. There are two parts to the cluster management model. One is the formation of cluster groups, consisting of all staff and facilitated by a cluster leader. The cluster groups function for communication and problem-solving. The second part of the cluster management model is the creation of task forces. These task forces are designed to work on short-term goals, usually in response to solving one of the unit's goals. Sometimes the task forces are used for quality improvement or system problems. Clusters are groups of not more than five or six staff members, facilitated by a cluster leader. A cluster is made up of individuals who work the same shift. For example, people with job titles who work days would be in a cluster. There would be registered nurses, licensed practical nurses, nursing assistants, and unit clerks in the cluster. The cluster leader is chosen by the manager based on certain criteria and is trained for this specialized role. The concept of cluster management, criteria for choosing leaders, training for leaders, using cluster groups to solve quality improvement issues, and the learning process necessary for manager support are described.

  4. Legacy ExtraGalactic UV Survey with The Hubble Space Telescope: Stellar Cluster Catalogs and First Insights Into Cluster Formation and Evolution in NGC 628

    Science.gov (United States)

    Adamo, A.; Ryon, J. E.; Messa, M.; Kim, H.; Grasha, K.; Cook, D. O.; Calzetti, D.; Lee, J. C.; Whitmore, B. C.; Elmegreen, B. G.; Ubeda, L.; Smith, L. J.; Bright, S. N.; Runnholm, A.; Andrews, J. E.; Fumagalli, M.; Gouliermis, D. A.; Kahre, L.; Nair, P.; Thilker, D.; Walterbos, R.; Wofford, A.; Aloisi, A.; Ashworth, G.; Brown, T. M.; Chandar, R.; Christian, C.; Cignoni, M.; Clayton, G. C.; Dale, D. A.; de Mink, S. E.; Dobbs, C.; Elmegreen, D. M.; Evans, A. S.; Gallagher, J. S., III; Grebel, E. K.; Herrero, A.; Hunter, D. A.; Johnson, K. E.; Kennicutt, R. C.; Krumholz, M. R.; Lennon, D.; Levay, K.; Martin, C.; Nota, A.; Östlin, G.; Pellerin, A.; Prieto, J.; Regan, M. W.; Sabbi, E.; Sacchi, E.; Schaerer, D.; Schiminovich, D.; Shabani, F.; Tosi, M.; Van Dyk, S. D.; Zackrisson, E.

    2017-06-01

    We report the large effort that is producing comprehensive high-level young star cluster (YSC) catalogs for a significant fraction of galaxies observed with the Legacy ExtraGalactic UV Survey (LEGUS) Hubble treasury program. We present the methodology developed to extract cluster positions, verify their genuine nature, produce multiband photometry (from NUV to NIR), and derive their physical properties via spectral energy distribution fitting analyses. We use the nearby spiral galaxy NGC 628 as a test case for demonstrating the impact that LEGUS will have on our understanding of the formation and evolution of YSCs and compact stellar associations within their host galaxy. Our analysis of the cluster luminosity function from the UV to the NIR finds a steepening at the bright end and at all wavelengths suggesting a dearth of luminous clusters. The cluster mass function of NGC 628 is consistent with a power-law distribution of slopes ˜ -2 and a truncation of a few times 105 {M}⊙ . After their formation, YSCs and compact associations follow different evolutionary paths. YSCs survive for a longer time frame, confirming their being potentially bound systems. Associations disappear on timescales comparable to hierarchically organized star-forming regions, suggesting that they are expanding systems. We find mass-independent cluster disruption in the inner region of NGC 628, while in the outer part of the galaxy there is little or no disruption. We observe faster disruption rates for low mass (≤104 {M}⊙ ) clusters, suggesting that a mass-dependent component is necessary to fully describe the YSC disruption process in NGC 628. Based on observations obtained with the NASA/ESA Hubble Space Telescope, at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.

  5. MN48: a new Galactic bona fide luminous blue variable revealed by Spitzer and SALT

    Science.gov (United States)

    Kniazev, A. Y.; Gvaramadze, V. V.; Berdnikov, L. N.

    2016-07-01

    In this paper, we report the results of spectroscopic and photometric observations of the candidate evolved massive star MN48 disclosed via detection of a mid-infrared circular shell around it with the Spitzer Space Telescope. Follow-up optical spectroscopy of MN48 with the Southern African Large Telescope (SALT) carried out in 2011-2015 revealed significant changes in the spectrum of this star, which are typical of luminous blue variables (LBVs). The LBV status of MN48 was further supported by photometric monitoring which shows that in 2009-2011 this star has brightened by ≈0.9 and 1 mag in the V and Ic bands, respectively, then faded by ≈1.1 and 1.6 mag during the next four years, and apparently started to brighten again recently. The detected changes in the spectrum and brightness of MN48 make this star the 18th known Galactic bona fide LBV and increase the percentage of LBVs associated with circumstellar nebulae to more than 70 per cent. We discuss the possible birth place of MN48 and suggest that this star might have been ejected either from a putative star cluster embedded in the H II region IRAS 16455-4531 or the young massive star cluster Westerlund 1.

  6. 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.

  7. Visual Perceptual Echo Reflects Learning of Regularities in Rapid Luminance Sequences.

    Science.gov (United States)

    Chang, Acer Y-C; Schwartzman, David J; VanRullen, Rufin; Kanai, Ryota; Seth, Anil K

    2017-08-30

    A novel neural signature of active visual processing has recently been described in the form of the "perceptual echo", in which the cross-correlation between a sequence of randomly fluctuating luminance values and occipital electrophysiological signals exhibits a long-lasting periodic (∼100 ms cycle) reverberation of the input stimulus (VanRullen and Macdonald, 2012). As yet, however, the mechanisms underlying the perceptual echo and its function remain unknown. Reasoning that natural visual signals often contain temporally predictable, though nonperiodic features, we hypothesized that the perceptual echo may reflect a periodic process associated with regularity learning. To test this hypothesis, we presented subjects with successive repetitions of a rapid nonperiodic luminance sequence, and examined the effects on the perceptual echo, finding that echo amplitude linearly increased with the number of presentations of a given luminance sequence. These data suggest that the perceptual echo reflects a neural signature of regularity learning.Furthermore, when a set of repeated sequences was followed by a sequence with inverted luminance polarities, the echo amplitude decreased to the same level evoked by a novel stimulus sequence. Crucially, when the original stimulus sequence was re-presented, the echo amplitude returned to a level consistent with the number of presentations of this sequence, indicating that the visual system retained sequence-specific information, for many seconds, even in the presence of intervening visual input. Altogether, our results reveal a previously undiscovered regularity learning mechanism within the human visual system, reflected by the perceptual echo. SIGNIFICANCE STATEMENT How the brain encodes and learns fast-changing but nonperiodic visual input remains unknown, even though such visual input characterizes natural scenes. We investigated whether the phenomenon of "perceptual echo" might index such learning. The perceptual echo is a

  8. Isotopic clusters

    International Nuclear Information System (INIS)

    Geraedts, J.M.P.

    1983-01-01

    Spectra of isotopically mixed clusters (dimers of SF 6 ) are calculated as well as transition frequencies. The result leads to speculations about the suitability of the laser-cluster fragmentation process for isotope separation. (Auth.)

  9. Cluster Headache

    Science.gov (United States)

    ... a role. Unlike migraine and tension headache, cluster headache generally isn't associated with triggers, such as foods, hormonal changes or stress. Once a cluster period begins, however, drinking alcohol ...

  10. Genomic and phylogenetic characterization of luminous bacteria symbiotic with the deep-sea fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae).

    Science.gov (United States)

    Dunlap, Paul V; Ast, Jennifer C

    2005-02-01

    Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of

  11. Cluster Headache

    OpenAIRE

    Pearce, Iris

    1985-01-01

    Cluster headache is the most severe primary headache with recurrent pain attacks described as worse than giving birth. The aim of this paper was to make an overview of current knowledge on cluster headache with a focus on pathophysiology and treatment. This paper presents hypotheses of cluster headache pathophysiology, current treatment options and possible future therapy approaches. For years, the hypothalamus was regarded as the key structure in cluster headache, but is now thought to be pa...

  12. Categorias Cluster

    OpenAIRE

    Queiroz, Dayane Andrade

    2015-01-01

    Neste trabalho apresentamos as categorias cluster, que foram introduzidas por Aslak Bakke Buan, Robert Marsh, Markus Reineke, Idun Reiten e Gordana Todorov, com o objetivo de categoriíicar as algebras cluster criadas em 2002 por Sergey Fomin e Andrei Zelevinsky. Os autores acima, em [4], mostraram que existe uma estreita relação entre algebras cluster e categorias cluster para quivers cujo grafo subjacente é um diagrama de Dynkin. Para isto desenvolveram uma teoria tilting na estrutura triang...

  13. A NEW TEST OF THE STATISTICAL NATURE OF THE BRIGHTEST CLUSTER GALAXIES

    International Nuclear Information System (INIS)

    Lin, Yen-Ting; Ostriker, Jeremiah P.; Miller, Christopher J.

    2010-01-01

    A novel statistic is proposed to examine the hypothesis that all cluster galaxies are drawn from the same luminosity distribution (LD). In such a 'statistical model' of galaxy LD, the brightest cluster galaxies (BCGs) are simply the statistical extreme of the galaxy population. Using a large sample of nearby clusters, we show that BCGs in high luminosity clusters (e.g., L tot ∼> 4 x 10 11 h -2 70 L sun ) are unlikely (probability ≤3 x 10 -4 ) to be drawn from the LD defined by all red cluster galaxies more luminous than M r = -20. On the other hand, BCGs in less luminous clusters are consistent with being the statistical extreme. Applying our method to the second brightest galaxies, we show that they are consistent with being the statistical extreme, which implies that the BCGs are also distinct from non-BCG luminous, red, cluster galaxies. We point out some issues with the interpretation of the classical tests proposed by Tremaine and Richstone (TR) that are designed to examine the statistical nature of BCGs, investigate the robustness of both our statistical test and those of TR against difficulties in photometry of galaxies of large angular size, and discuss the implication of our findings on surveys that use the luminous red galaxies to measure the baryon acoustic oscillation features in the galaxy power spectrum.

  14. THE EVOLUTION OF DUSTY STAR FORMATION IN GALAXY CLUSTERS TO z = 1: SPITZER INFRARED OBSERVATIONS OF THE FIRST RED-SEQUENCE CLUSTER SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Webb, T. M. A.; O' Donnell, D.; Coppin, Kristen; Faloon, Ashley; Geach, James E.; Noble, Allison [McGill University, 3600 rue University, Montreal, QC, H3A 2T8 (Canada); Yee, H. K. C. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George St., Toronto, ON, M5S 3H4 (Canada); Gilbank, David [South African Astronomical Observatory, P.O. Box 9, Observatory, 7935 (South Africa); Ellingson, Erica [Department of Astrophysical and Planetary Sciences, University of Colorado at Boulder, Boulder, CO 80309 (United States); Gladders, Mike [Department of Astronomy and Astrophysics, University of Chicago, 5640 S. Ellis Ave., Chicago, IL 60637 (United States); Muzzin, Adam [Leiden Observatory, University of Leiden, Niels Bohrweg 2, NL-2333 CA, Leiden (Netherlands); Wilson, Gillian [Department of Physics and Astronomy, University of California at Riverside, 900 University Avenue, Riverside, CA 92521 (United States); Yan, Renbin [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)

    2013-10-01

    We present the results of an infrared (IR) study of high-redshift galaxy clusters with the MIPS camera on board the Spitzer Space Telescope. We have assembled a sample of 42 clusters from the Red-Sequence Cluster Survey-1 over the redshift range 0.3 < z < 1.0 and spanning an approximate range in mass of 10{sup 14-15} M {sub ☉}. We statistically measure the number of IR-luminous galaxies in clusters above a fixed inferred IR luminosity of 2 × 10{sup 11} M {sub ☉}, assuming a star forming galaxy template, per unit cluster mass and find it increases to higher redshift. Fitting a simple power-law we measure evolution of (1 + z){sup 5.1±1.9} over the range 0.3 < z < 1.0. These results are tied to the adoption of a single star forming galaxy template; the presence of active galactic nuclei, and an evolution in their relative contribution to the mid-IR galaxy emission, will alter the overall number counts per cluster and their rate of evolution. Under the star formation assumption we infer the approximate total star formation rate per unit cluster mass (ΣSFR/M {sub cluster}). The evolution is similar, with ΣSFR/M {sub cluster} ∼ (1 + z){sup 5.4±1.9}. We show that this can be accounted for by the evolution of the IR-bright field population over the same redshift range; that is, the evolution can be attributed entirely to the change in the in-falling field galaxy population. We show that the ΣSFR/M {sub cluster} (binned over all redshift) decreases with increasing cluster mass with a slope (ΣSFR/M{sub cluster}∼M{sub cluster}{sup -1.5±0.4}) consistent with the dependence of the stellar-to-total mass per unit cluster mass seen locally. The inferred star formation seen here could produce ∼5%-10% of the total stellar mass in massive clusters at z = 0, but we cannot constrain the descendant population, nor how rapidly the star-formation must shut-down once the galaxies have entered the cluster environment. Finally, we show a clear decrease in the number of IR

  15. Meaningful Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Calapristi, Augustin J.; Crow, Vernon L.; Hetzler, Elizabeth G.; Turner, Alan E.

    2004-05-26

    We present an approach to the disambiguation of cluster labels that capitalizes on the notion of semantic similarity to assign WordNet senses to cluster labels. The approach provides interesting insights on how document clustering can provide the basis for developing a novel approach to word sense disambiguation.

  16. Horticultural cluster

    OpenAIRE

    SHERSTIUK S.V.; POSYLAYEVA K.I.

    2013-01-01

    In the article there are the theoretical and methodological approaches to the nature and existence of the cluster. The cluster differences from other kinds of cooperative and integration associations. Was develop by scientific-practical recommendations for forming a competitive horticultur cluster.

  17. Effect of low-dose ionizing radiation on luminous marine bacteria: radiation hormesis and toxicity.

    Science.gov (United States)

    Kudryasheva, N S; Rozhko, T V

    2015-04-01

    The paper summarizes studies of effects of alpha- and beta-emitting radionuclides (americium-241, uranium-235+238, and tritium) on marine microorganisms under conditions of chronic low-dose irradiation in aqueous media. Luminous marine bacteria were chosen as an example of these microorganisms; bioluminescent intensity was used as a tested physiological parameter. Non-linear dose-effect dependence was demonstrated. Three successive stages in the bioluminescent response to americium-241 and tritium were found: 1--absence of effects (stress recognition), 2--activation (adaptive response), and 3--inhibition (suppression of physiological function, i.e. radiation toxicity). The effects were attributed to radiation hormesis phenomenon. Biological role of reactive oxygen species, secondary products of the radioactive decay, is discussed. The study suggests an approach to evaluation of non-toxic and toxic stages under conditions of chronic radioactive exposure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Psychophysical Measurements of Luminance Contrast Sensitivity and Color Discrimination with Transparent and Blue-Light Filter Intraocular Lenses.

    Science.gov (United States)

    da Costa, Marcelo Fernandes; Júnior, Augusto Paranhos; Lottenberg, Claudio Luiz; Castro, Leonardo Cunha; Ventura, Dora Fix

    2017-12-01

    The purpose of this study was to measure luminance contrast sensitivity and color vision thresholdfs in normal subjects using a blue light filter lens and transparent intraocular lens material. Monocular luminance grating contrast sensitivity was measured with Psycho for Windows (version 2.36; Cambridge Research Systems) at 3.0, 6.0, 12.0, 20.0, and 30.0 cycles per degree of visual angle (cpd) in 15 normal subjects (eight female), with a mean age of 21.6 years (SD = 3.8 years). Chromatic discrimination was assessed with the Cambridge colour test (CCT) along the protan, deutan, and tritan color confusion axes. Both tests were performed in a darkened room under two situations: with a transparent lens and with blue light filter lens. Subjective impressions were taken by subjects regarding their visual experience under both conditions. No difference was found between the luminance contrast sensitivity measured with transparent and blue light filter. However, 13/15 (87%) of the subjects reported more comfortable vision with the blue filter. In the color vision test, tritan thresholds were significantly higher for the blue filter compared with the transparent filter (p = 0.003). For protan and deutan thresholds no differences were found. Blue-yellow color vision is impaired with the blue light filter, and no impairment occurs with the transparent filter. No significant differences in thresholds were found in the luminance contrast sensitivity comparing the blue light and transparent filters. The impact of short wavelength light filtering on intrinsically photosensitive retinal ganglion cells is also discussed.

  19. Cluster Matters

    DEFF Research Database (Denmark)

    Gulati, Mukesh; Lund-Thomsen, Peter; Suresh, Sangeetha

    2018-01-01

    sell their products successfully in international markets, but there is also an increasingly large consumer base within India. Indeed, Indian industrial clusters have contributed to a substantial part of this growth process, and there are several hundred registered clusters within the country...... of this handbook, which focuses on the role of CSR in MSMEs. Hence we contribute to the literature on CSR in industrial clusters and specifically CSR in Indian industrial clusters by investigating the drivers of CSR in India’s industrial clusters....

  20. A filament of dark matter between two clusters of galaxies.

    Science.gov (United States)

    Dietrich, Jörg P; Werner, Norbert; Clowe, Douglas; Finoguenov, Alexis; Kitching, Tom; Miller, Lance; Simionescu, Aurora

    2012-07-12

    It is a firm prediction of the concordance cold-dark-matter cosmological model that galaxy clusters occur at the intersection of large-scale structure filaments. The thread-like structure of this 'cosmic web' has been traced by galaxy redshift surveys for decades. More recently, the warm–hot intergalactic medium (a sparse plasma with temperatures of 10(5) kelvin to 10(7) kelvin) residing in low-redshift filaments has been observed in emission and absorption. However, a reliable direct detection of the underlying dark-matter skeleton, which should contain more than half of all matter, has remained elusive, because earlier candidates for such detections were either falsified or suffered from low signal-to-noise ratios and unphysical misalignments of dark and luminous matter. Here we report the detection of a dark-matter filament connecting the two main components of the Abell 222/223 supercluster system from its weak gravitational lensing signal, both in a non-parametric mass reconstruction and in parametric model fits. This filament is coincident with an overdensity of galaxies and diffuse, soft-X-ray emission, and contributes a mass comparable to that of an additional galaxy cluster to the total mass of the supercluster. By combining this result with X-ray observations, we can place an upper limit of 0.09 on the hot gas fraction (the mass of X-ray-emitting gas divided by the total mass) in the filament.

  1. Development of a LED based standard for luminous flux

    Science.gov (United States)

    Sardinha, André; Ázara, Ivo; Torres, Miguel; Menegotto, Thiago; Grieneisen, Hans Peter; Borghi, Giovanna; Couceiro, Iakyra; Zim, Alexandre; Muller, Filipe

    2018-03-01

    Incandescent lamps, simple artifacts with radiation spectrum very similar to a black-body emitter, are traditional standards in photometry. Nowadays LEDs are broadly used in lighting, with great variety of spectra, and it is convenient to use standards for photometry with spectral distribution similar to that of the measured artifact. Research and development of such standards occur in several National Metrology Institutes. In Brazil, Inmetro is working on a practical solution for providing a LED based standard to be used for luminous flux measurements in the field of general lighting. This paper shows the measurements made for the developing of a prototype, that in sequence will be characterized in photometric quantities.

  2. Ultra-luminous X-ray sources and intermediate-mass black holes

    International Nuclear Information System (INIS)

    Cseh, David

    2012-01-01

    More than ten years ago, the discovery of Ultra-luminous X-ray sources (ULXs) has opened up an entirely new field in astrophysics. Many ideas were developed to explain the nature of these sources, like their emission mechanism, mass, and origin, without any strong conclusions. Their discovery boosted the fields of X-ray binaries, accretion physics, stellar evolution, cosmology, black hole formation and growth, due to the concept of intermediate-mass black holes (IMBHs). Since their discovery is related to the domain of X-ray astrophysics, there have been very few studies made in other wavelengths. This thesis focuses on the multiwavelength nature of Ultra-luminous X-ray sources and intermediate-mass black holes from various aspects, which help to overcome some difficulties we face today. First, I investigated the accretion signatures of a putative intermediate-mass black hole in a particular globular cluster. To this purpose, I characterized the nature of the innermost X-ray sources in the cluster. Then I calculated an upper limit on the mass of the black hole by studying possible accretion efficiencies and rates based on the dedicated X-ray and radio observations. The accreting properties of the source was described with standard spherical accretion and in the context of inefficient accretion. Secondly, I attempted to dynamically measure the mass of the black hole in a particular ULX via optical spectroscopy. I discovered that a certain emission line has a broad component that markedly shifts in wavelength. I investigated the possibility whether this line originates in the accretion disk, and thus might trace the orbital motion of the binary system. I also characterized the parameters of the binary system, such as the mass function, possible orbital separation, the size of the line-emitting region, and an upper limit on the mass of the black hole. Then I studied the environment of a number of ULXs that are associated with large-scale optical and radio nebulae. I

  3. Clustering of resting state networks.

    Directory of Open Access Journals (Sweden)

    Megan H Lee

    Full Text Available The goal of the study was to demonstrate a hierarchical structure of resting state activity in the healthy brain using a data-driven clustering algorithm.The fuzzy-c-means clustering algorithm was applied to resting state fMRI data in cortical and subcortical gray matter from two groups acquired separately, one of 17 healthy individuals and the second of 21 healthy individuals. Different numbers of clusters and different starting conditions were used. A cluster dispersion measure determined the optimal numbers of clusters. An inner product metric provided a measure of similarity between different clusters. The two cluster result found the task-negative and task-positive systems. The cluster dispersion measure was minimized with seven and eleven clusters. Each of the clusters in the seven and eleven cluster result was associated with either the task-negative or task-positive system. Applying the algorithm to find seven clusters recovered previously described resting state networks, including the default mode network, frontoparietal control network, ventral and dorsal attention networks, somatomotor, visual, and language networks. The language and ventral attention networks had significant subcortical involvement. This parcellation was consistently found in a large majority of algorithm runs under different conditions and was robust to different methods of initialization.The clustering of resting state activity using different optimal numbers of clusters identified resting state networks comparable to previously obtained results. This work reinforces the observation that resting state networks are hierarchically organized.

  4. Luminal epithelial cells within the mammary gland can produce basal cells upon oncogenic stress.

    Science.gov (United States)

    Hein, S M; Haricharan, S; Johnston, A N; Toneff, M J; Reddy, J P; Dong, J; Bu, W; Li, Y

    2016-03-17

    In the normal mammary gland, the basal epithelium is known to be bipotent and can generate either basal or luminal cells, whereas the luminal epithelium has not been demonstrated to contribute to the basal compartment in an intact and normally developed mammary gland. It is not clear whether cellular heterogeneity within a breast tumor results from transformation of bipotent basal cells or from transformation and subsequent basal conversion of the more differentiated luminal cells. Here we used a retroviral vector to express an oncogene specifically in a small number of the mammary luminal epithelial cells and tested their potential to produce basal cells during tumorigenesis. This in-vivo lineage-tracing work demonstrates that luminal cells are capable of producing basal cells on activation of either polyoma middle T antigen or ErbB2 signaling. These findings reveal the plasticity of the luminal compartment during tumorigenesis and provide an explanation for cellular heterogeneity within a cancer.

  5. Psychophysical and physiological responses to gratings with luminance and chromatic components of different spatial frequencies.

    Science.gov (United States)

    Cooper, Bonnie; Sun, Hao; Lee, Barry B

    2012-02-01

    Gratings that contain luminance and chromatic components of different spatial frequencies were used to study the segregation of signals in luminance and chromatic pathways. Psychophysical detection and discrimination thresholds to these compound gratings, with luminance and chromatic components of the one either half or double the spatial frequency of the other, were measured in human observers. Spatial frequency tuning curves for detection of compound gratings followed the envelope of those for luminance and chromatic gratings. Different grating types were discriminable at detection threshold. Fourier analysis of physiological responses of macaque retinal ganglion cells to compound waveforms showed chromatic information to be restricted to the parvocellular pathway and luminance information to the magnocellular pathway. Taken together, the human psychophysical and macaque physiological data support the strict segregation of luminance and chromatic information in independent channels, with the magnocellular and parvocellular pathways, respectively, serving as likely the physiological substrates. © 2012 Optical Society of America

  6. Observations of copper clustering in a 25Cr-7Ni super duplex stainless steel during low-temperature aging under load

    Science.gov (United States)

    Thuvander, M.; Zhou, J.; Odqvist, J.; Hertzman, S.; Hedström, P.

    2012-07-01

    Atom-probe tomography was used to investigate phase separation and copper (Cu) clustering in the ferrite phase of a 25Cr-7Ni super duplex stainless steel. The steel was subjected to a tensile load during aging at 325°C for 5800 h. The degree of phase separation into α (Fe-rich) and α‧ (Cr-rich) was small, but still, it was the highest in the steel subjected to the highest load. Cu was found to cluster, and the number density of clusters increased with increasing load. In the material subjected to the highest load, Cu was enriched in regions that were neither Fe-rich nor Cr-rich. These regions also had the highest number density of Cu clusters.

  7. Active Luminous Blue Variables in the Large Magellanic Cloud

    Energy Technology Data Exchange (ETDEWEB)

    Walborn, Nolan R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Gamen, Roberto C.; Lajús, Eduardo Fernández [Instituto de Astrofísica de La Plata, CONICET–UNLP and Facultad de Ciencias Astronómicas y Geofísicas, UNLP, Paseo del Bosque s/n, La Plata (Argentina); Morrell, Nidia I. [Las Campanas Observatory, Carnegie Observatories, Casilla 601, La Serena (Chile); Barbá, Rodolfo H. [Departamento de Física y Astronomía, Universidad de La Serena, Cisternas 1200 Norte, La Serena (Chile); Angeloni, Rodolfo, E-mail: walborn@stsci.edu, E-mail: rgamen@fcaglp.unlp.edu.ar, E-mail: eflajus@fcaglp.unlp.edu.ar, E-mail: nmorrell@lco.cl, E-mail: rbarba@dfuls.cl, E-mail: rangelon@gemini.edu [Gemini Observatory, Colina El Pino, Casilla 603, La Serena (Chile)

    2017-07-01

    We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca ii] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

  8. The Highly Luminous Type Ibn Supernova ASASSN-14ms

    DEFF Research Database (Denmark)

    Vallely, P. J.; Prieto, J. L.; Stanek, K. Z.

    2018-01-01

    We present photometric and spectroscopic follow-up observations of the highly luminous Type Ibn supernova ASASSN-14ms, which was discovered on UT 2014-12-26.61 at $m_V \\sim 16.5$. With a peak absolute $V$-band magnitude brighter than $-20.5$, a peak bolometric luminosity of $1.7 \\times 10......^{44}$ ergs s$^{-1}$, and a total radiated energy of $2.1 \\times 10^{50}$ ergs, ASASSN-14ms is one of the most luminous Type Ibn supernovae yet discovered. In simple models, the most likely power source for this event is a combination of the radioactive decay of $^{56}$Ni and $^{56}$Co at late times...... and the interaction of supernova ejecta with the progenitor's circumstellar medium at early times, although we cannot rule out the possibility of a magnetar-powered light curve. The presence of a dense circumstellar medium is indicated by the intermediate-width He I features in the spectra. The faint ($m_g \\sim 21...

  9. Effect of americium-241 on luminous bacteria. Role of peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrova, M., E-mail: maka-alexandrova@rambler.r [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Rozhko, T. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Vydryakova, G. [Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation); Kudryasheva, N. [Siberian Federal University, Svobodny 79, 660041 Krasnoyarsk (Russian Federation); Institute of Biophysics SB RAS, Akademgorodok 50, 660036 Krasnoyarsk (Russian Federation)

    2011-04-15

    The effect of americium-241 ({sup 241}Am), an alpha-emitting radionuclide of high specific activity, on luminous bacteria Photobacterium phosphoreum was studied. Traces of {sup 241}Am in nutrient media (0.16-6.67 kBq/L) suppressed the growth of bacteria, but enhanced luminescence intensity and quantum yield at room temperature. Lower temperature (4 {sup o}C) increased the time of bacterial luminescence and revealed a stage of bioluminescence inhibition after 150 h of bioluminescence registration start. The role of conditions of exposure the bacterial cells to the {sup 241}Am is discussed. The effect of {sup 241}Am on luminous bacteria was attributed to peroxide compounds generated in water solutions as secondary products of radioactive decay. Increase of peroxide concentration in {sup 241}Am solutions was demonstrated; and the similarity of {sup 241}Am and hydrogen peroxide effects on bacterial luminescence was revealed. The study provides a scientific basis for elaboration of bioluminescence-based assay to monitor radiotoxicity of alpha-emitting radionuclides in aquatic solutions. - Highlights: {yields} Am-241 in water solutions (A = 0.16-6.7 kBq/L) suppresses bacterial growth.{yields} Am-241 (A = 0.16-6.7 kBq/L) stimulate bacterial luminescence. {yields} Peroxides, secondary radiolysis products, cause increase of bacterial luminescence.

  10. Luminal digestion of lactoferrin in suckling and weanling rats

    International Nuclear Information System (INIS)

    Britton, J.R.; Koldovsky, O.

    1987-01-01

    The development of luminal digestion of lactoferrin was evaluated in vitro by incubating 125 I-labeled lactoferrin with fluid flushed from the stomach and small intestine of 12-day-old suckling and 31-day-old weanling rats, followed by measurement of radioactivity in trichloroacetic acid-soluble material. Gastric hydrolysis of lactoferrin at pH 3.2 in the weanling was 20-fold greater than that in the suckling. In the small intestine at neutral pH, luminal degradation of lactoferrin was minimal in the suckling but increased significantly after weaning, with maximal degradative capacity demonstrable in the midjejunum. Sephadex G-75 chromatography of intestinal acid-soluble breakdown products revealed two peaks of radioactivity, each comprising 40-45% of the total product; analysis of intestinal acid-precipitable products by polyacrylamide gel electrophoresis yielded several discrete lower molecular weight species. Food deprivation for 12 h/100 g body wt decreased lactoferrin degradation in the weanling jejunum and midjejunum. The findings suggest that lactoferrin digestion may vary with respect to postnatal age of the organism, segment of the gastrointestinal tract, and dietary state. In the young animal, lactoferrin degradation is minimal, and consequently its potential for biological function may be high

  11. Active Luminous Blue Variables in the Large Magellanic Cloud

    Science.gov (United States)

    Walborn, Nolan R.; Gamen, Roberto C.; Morrell, Nidia I.; Barbá, Rodolfo H.; Fernández Lajús, Eduardo; Angeloni, Rodolfo

    2017-07-01

    We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca II] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

  12. Active Luminous Blue Variables in the Large Magellanic Cloud

    International Nuclear Information System (INIS)

    Walborn, Nolan R.; Gamen, Roberto C.; Lajús, Eduardo Fernández; Morrell, Nidia I.; Barbá, Rodolfo H.; Angeloni, Rodolfo

    2017-01-01

    We present extensive spectroscopic and photometric monitoring of two famous and currently highly active luminous blue variables (LBVs) in the Large Magellanic Cloud (LMC), together with more limited coverage of three further, lesser known members of the class. R127 was discovered as an Ofpe/WN9 star in the 1970s but entered a classical LBV outburst in or about 1980 that is still in progress, thus enlightening us about the minimum state of such objects. R71 is currently the most luminous star in the LMC and continues to provide surprises, such as the appearance of [Ca ii] emission lines, as its spectral type becomes unprecedentedly late. Most recently, R71 has developed inverse P Cyg profiles in many metal lines. The other objects are as follows: HDE 269582, now a “second R127” that has been followed from Ofpe/WN9 to A type in its current outburst; HDE 269216, which changed from late B in 2014 to AF in 2016, its first observed outburst; and R143 in the 30 Doradus outskirts. The light curves and spectroscopic transformations are correlated in remarkable detail and their extreme reproducibility is emphasized, both for a given object and among all of them. It is now believed that some LBVs proceed directly to core collapse. One of these unstable LMC objects may thus oblige in the near future, teaching us even more about the final stages of massive stellar evolution.

  13. The Effect of Improved Water Supply on Diarrhea Prevalence of Children under Five in the Volta Region of Ghana: A Cluster-Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Seungman Cha

    2015-09-01

    Full Text Available Although a number of studies have been conducted to explore the effect of water quality improvement, the majority of them have focused mainly on point-of-use water treatment, and the studies investigating the effect of improved water supply have been based on observational or inadequately randomized trials. We report the results of a matched cluster randomized trial investigating the effect of improved water supply on diarrheal prevalence of children under five living in rural areas of the Volta Region in Ghana. We compared the diarrheal prevalence of 305 children in 10 communities of intervention with 302 children in 10 matched communities with no intervention (October 2012 to February 2014. A modified Poisson regression was used to estimate the prevalence ratio. An intention-to-treat analysis was undertaken. The crude prevalence ratio of diarrhea in the intervention compared with the control communities was 0.85 (95% CI 0.74–0.97 for Krachi West, 0.96 (0.87–1.05 for Krachi East, and 0.91 (0.83–0.98 for both districts. Sanitation was adjusted for in the model to remove the bias due to residual imbalance since it was not balanced even after randomization. The adjusted prevalence ratio was 0.82 (95% CI 0.71–0.96 for Krachi West, 0.95 (0.86–1.04 for Krachi East, and 0.89 (0.82–0.97 for both districts. This study provides a basis for a better approach to water quality interventions.

  14. THE PRODUCTION RATE OF SN Ia EVENTS IN GLOBULAR CLUSTERS

    International Nuclear Information System (INIS)

    Washabaugh, Pearce C.; Bregman, Joel N.

    2013-01-01

    In globular clusters, dynamical evolution produces luminous X-ray emitting binaries at a rate about 200 times greater than in the field. If globular clusters also produce SN Ia at a high rate, it would account for many of the SN Ia production in early-type galaxies and provide insight into their formation. Here we use archival Hubble Space Telescope (HST) images of nearby galaxies that have hosted an SN Ia to examine the rate at which globular clusters produce these events. The location of the SN Ia is registered on an HST image obtained before the event or after the supernova (SN) faded. Of the 36 nearby galaxies examined, 21 had sufficiently good data to search for globular cluster hosts. None of the 21 SNe have a definite globular cluster counterpart, although there are some ambiguous cases. This places an upper limit to the enhancement rate of SN Ia production in globular clusters of about 42 at the 95% confidence level, which is an order of magnitude lower than the enhancement rate for luminous X-ray binaries. Even if all of the ambiguous cases are considered as having a globular cluster counterpart, the upper bound for the enhancement rate is 82 at the 95% confidence level, still a factor of several below that needed to account for half of the SN Ia events. Barring unforeseen selection effects, we conclude that globular clusters are not responsible for producing a significant fraction of the SN Ia events in early-type galaxies.

  15. Magnetic resonance evaluation of luminal patency after polylactide stent implantation: an experimental study in a rabbit aorta model

    International Nuclear Information System (INIS)

    Hietala, Eeva-Maija; Salminen, Ulla-Stina; Harjula, Ari L.J.; Maasilta, Paula; Staahls, Anders; Vaelimaa, Tero; Kivisaari, Leena

    2003-01-01

    Intravascular metallic stents cause magnetic field distortions, disturbing luminal detection. Our aim was to evaluate the effect of polylactic acid (PLA) stents on magnetic resonance angiography (MRA). Biodegradable double spiral helical PLA stents (n=12) or stainless steel (SS) (n=6) stents were implanted into the infrarenal aortas of New Zealand White rabbits. All SS- and 6 PLA-stented animals as well as 6 non-operated control rabbits were imaged with gadolinium-enhanced MRA (1.5 T), and infrarenal aortic diameters (proximal, distal, and narrowest), together with the stent artifact, were measured. Six of the PLA-stented rabbits were followed up, and MRA was assessed at 2, 6, 9, and 12 months after the stent implantation. Image artifacts caused by the SS stents were visualized in all cases. The PLA stents caused no magnetic field distortion, allowing imaging of the underlying vessel including the vessel lumen. In the follow-up group of 6 rabbits with a PLA stent, 5 of 6 were patent at the end of the follow-up of 12 months. These stents allowed luminal detection at all time points, with no significant differences in aortic measurements emerging during the whole follow-up period. When immediately postoperatively scanned SS and PLA rabbits were compared with controls, no differences were observable in proximal diameters. Instead, the percentage of distal luminal loss was greater in the PLA-stented rabbits, as compared with SS stents (p<0.01). The PLA stenting in small vessels allows evaluation of luminal patency with MRA both immediately after implantation and during follow-up. (orig.)

  16. Contextualizing the Cluster

    DEFF Research Database (Denmark)

    Giacomin, Valeria

    This dissertation examines the case of the palm oil cluster in Malaysia and Indonesia, today one of the largest agricultural clusters in the world. My analysis focuses on the evolution of the cluster from the 1880s to the 1970s in order to understand how it helped these two countries to integrate...... into the global economy in both colonial and post-colonial times. The study is based on empirical material drawn from five UK archives and background research using secondary sources, interviews, and archive visits to Malaysia and Singapore. The dissertation comprises three articles, each discussing a major under...

  17. Cluster evolution

    International Nuclear Information System (INIS)

    Schaeffer, R.

    1987-01-01

    The galaxy and cluster luminosity functions are constructed from a model of the mass distribution based on hierarchical clustering at an epoch where the matter distribution is non-linear. These luminosity functions are seen to reproduce the present distribution of objects as can be inferred from the observations. They can be used to deduce the redshift dependence of the cluster distribution and to extrapolate the observations towards the past. The predicted evolution of the cluster distribution is quite strong, although somewhat less rapid than predicted by the linear theory

  18. Application of radioisotope for radio-luminous watch and clock industry in Japan

    International Nuclear Information System (INIS)

    Murayama, Yoshihiko

    1981-01-01

    In 1979, Japan became No. 1 watch and clock production country in the world, and has produced 88 million watches and 59 million clocks in 1980. About 65% of them were exported. The production of radio-luminous watches and clocks in 1980 was estimated as 13 million and 11 million, respectively, and has increased by 40% as compared with the previous year. In Japan, the law concerning the prevention of radiation injuries due to radioisotopes and others is applied to radio-luminous watches and clocks, because radioactive substances are contained in luminous paint, and the production is regulated by the law as unsealed RI-using establishments. The permitted establishments engaging in radio-luminous watches and clocks are 3 luminous paint makers, 9 painting works and 35 watch and clock assembling plants. The RI utilized for radio-luminous watches and clocks is limited to Pm-147 at present, and 3788 Ci was used in 1980. About 70 years have elapsed since luminous paint was used for watches and clocks for the first time. The ISO instituted the international standard on radio-luminous paint for watches and clocks in 1975. The beta-ray emitted by Pm-147 is shielded perfectly by glasses and cases, and only the dose of brems-strahlung X-ray is the problem. The radiation control in radio-luminous watch and clock plants is described. (Kako, I.)

  19. Identification of Different Classes of Luminal Progenitor Cells within Prostate Tumors

    Directory of Open Access Journals (Sweden)

    Supreet Agarwal

    2015-12-01

    Full Text Available Primary prostate cancer almost always has a luminal phenotype. However, little is known about the stem/progenitor properties of transformed cells within tumors. Using the aggressive Pten/Tp53-null mouse model of prostate cancer, we show that two classes of luminal progenitors exist within a tumor. Not only did tumors contain previously described multipotent progenitors, but also a major population of committed luminal progenitors. Luminal cells, sorted directly from tumors or grown as organoids, initiated tumors of adenocarcinoma or multilineage histological phenotypes, which is consistent with luminal and multipotent differentiation potentials, respectively. Moreover, using organoids we show that the ability of luminal-committed progenitors to self-renew is a tumor-specific property, absent in benign luminal cells. Finally, a significant fraction of luminal progenitors survived in vivo castration. In all, these data reveal two luminal tumor populations with different stem/progenitor cell capacities, providing insight into prostate cancer cells that initiate tumors and can influence treatment response.

  20. Signal detectability of mammography depends on film-screen system and luminance of view box

    International Nuclear Information System (INIS)

    Maeda, Fumie; Ogura, Akio; Miyai, Akira

    2003-01-01

    High-density film and the high-luminance view-box system are being recommended for mammograms owing to the improved detection of masses. However, this system causes an increase in radiation. Therefore, the purpose of this study was to assess whether the detection of masses would improve using the normal-luminance view box and normal-density film with different types of contrast systems. Low-contrast detection using receiver operating characteristic (ROC) analysis and high-contrast detection using an American College of Radiology (ACR) phantom were evaluated for the following systems: high-density film and high-luminance view box, normal-density film and normal-luminance view box, and normal-density film with wide latitude and normal-luminance view box. The results showed no significant variation in the detectability of the system with high-density film and high-luminance view box and the normal-density film with wide latitude and normal-luminance view box. However, in terms of low-contrast visibility, the system using normal-density film and normal-luminance view box was significantly reduced in comparison with the others. Therefore, the system with normal-density film with wide latitude and the normal-luminance view box is recommended because of reduced radiation dose. (author)

  1. Fermion cluster algorithms

    International Nuclear Information System (INIS)

    Chandrasekharan, Shailesh

    2000-01-01

    Cluster algorithms have been recently used to eliminate sign problems that plague Monte-Carlo methods in a variety of systems. In particular such algorithms can also be used to solve sign problems associated with the permutation of fermion world lines. This solution leads to the possibility of designing fermion cluster algorithms in certain cases. Using the example of free non-relativistic fermions we discuss the ideas underlying the algorithm

  2. Luminous Quasars Do Not Live in Overdense Regions of LBGS at z 4

    Science.gov (United States)

    Uchiyama, Hisakazu

    2017-07-01

    We present the cross-correlation between 151 luminous QSOs and 179 protoclustercandidates at z 4 using Hyper Suprime-Cam data. We found that only 2 QSOs reside inregions that are more overdense compared to the average field at > 4σ. The distributionsof the distance between QSOs and the nearest protoclusters and the signicance of theoverdensity at the position of QSOs are statistically identical to those found for LBGs,suggesting that QSOs tend to reside in almost the same environment as LBGs at thisredshift. Using stacking analysis, we found that the average density of LBGs around QSOsis slightly higher than that around LBGs on 1.0-2.5 pMpc scales, while at anti-correlated with overdensity. These findings are consistentwith a scenario in which the average QSO at z 4 resides in structures that are lessmassive than those expected for the progenitors of today's rich clusters, and possibly thatluminous QSOs may be suppressing star formation in their close vicinity.

  3. Colour polymorphic lures exploit innate preferences for spectral versus luminance cues in dipteran prey.

    Science.gov (United States)

    White, Thomas E; Kemp, Darrell J

    2017-08-14

    Theory predicts that colour polymorphism may be favored by variation in the visual context under which signals are perceived. The context encompasses all environmental determinants of light availability and propagation, but also the dynamics of perception in receivers. Color vision involves the neural separation of information into spectral versus luminance channels, which often differentially guide specific tasks. Here we explicitly tested whether this discrete perceptual basis contributes to the maintenance of polymorphism in a prey-luring system. The orb-weaving spider Gasteracantha fornicata is known to attract a broad community of primarily dipteran prey due to their conspicuous banded dorsal signal. They occur in two morphs ("white" and "yellow") which should, respectively, generate greater luminance and color contrast in the dipteran eye. Given that arthropods often rely upon luminance-versus-spectral cues for relatively small-versus-large stimulus detection, we predicted a switch in relative attractiveness among morphs according to apparent spider size. Our experimental tests used colour-naïve individuals of two known prey species (Drosophila hydei and Musca domestica) in replicate Y-maze choice trials designed to manipulate the apparent size of spider models via the distance at which they are viewed. Initial trials confirmed that flies were attracted to each G. fornicata morph in single presentations. When given a simultaneous choice between morphs against a viewing background typical of those encountered in nature, flies exhibited no preference regardless of the visual angle subtended by models. However, when backgrounds were adjusted to nearer the extremes of those of each morph in the wild, flies were more attracted by white morphs when presented at longer range (consistent with a reliance on achromatic cues), yet were unbiased in their close-range choice. While not fully consistent with predictions (given the absence of a differential preference for

  4. Can Histological Grade and Mitotic Index Replace Ki67 to Determine Luminal Breast Cancer Subtypes?

    Science.gov (United States)

    Oddó, David; Pulgar, Dahiana; Elgueta, Nicole; Acevedo, Francisco; Razmiliz, Dravna; Navarro, María Elena; Camus, Mauricio; Merino, Tomás; Retamal, Ignacio; Pérez-Sepúlveda, Alejandra; Villarroel, Alejandra; Galindo, Héctor; Peña, José; Sánchez, César

    2018-01-27

    Introduction: Breast cancer can be classified into subtypes based on immunohistochemical markers, with Ki67 expression levels being used to divide luminal BC tumors in luminal A and B subtypes; however, Ki67 is not routinely determined due to a lack of standardization. Objective: To evaluate histological grade and Eliminate: the mitotic index to determine if they can be used as an alternative method to Ki67 staining for luminal subtype definition. Methods: We evaluated estrogen receptor positive breast cancer tissue samples. Pathological analysis included determination of Ki67. A low level of Ki67 was defined as <14% positive cells. Results: We evaluated 151 breast cancer samples; 24 (15,9%) were classified as I; 74 as HG II (49%), and 53 (35,1%) as HG III. The median value for Ki67 was 13% (range: <1% - 82%) and for MI was 2 (0-12). Histological grade I tumors exhibited Ki67 values significantly lower than HG II and III tumors (Anova, Tamhane test p=0,001). A higher Ki67 value was related to a higher MI (Rho Sperman p=0,336; R2= 0,0273). ROC curve analysis determined that a MI ≥ 3 had a sensibility of 61.9% and specificity of 66.7% in predicting a high Ki67 value (≥14%) (area under the curve: 0,691; p =0,0001). A HG I tumor or HG II-III with MI ≤2, had a high probability of corresponding to a LA tumor (76,3%), as defined using Ki67 expression, while the probability of a LB subtype was higher with HG II-III and a MI ≥3 (57.4%). Global discrimination was 68.1%. Conclusions: For the LA subtype, our predictive model showed a good correlation of HG and MI with the classification based on Ki67<14%. In the LB subtype, the model showed a weak correlation; therefore Ki67 determination seems to be needed for this group of patients. Creative Commons Attribution License

  5. Comparison of luminance based metrics in different lighting conditions

    DEFF Research Database (Denmark)

    Wienold, J.; Kuhn, T.E.; Christoffersen, J.

    In this study, we evaluate established and newly developed metrics for predicting glare using data from three different research studies. The evaluation covers two different targets: 1. How well the user’s perception of glare magnitude correlates to the prediction of the glare metrics? 2. How well...... do the glare metrics describe the subjects’ disturbance by glare? We applied Spearman correlations, logistic regressions and an accuracy evaluation, based on an ROC-analysis. The results show that five of the twelve investigated metrics are failing at least one of the statistical tests. The other...... seven metrics CGI, modified DGI, DGP, Ev, average Luminance of the image Lavg, UGP and UGR are passing all statistical tests. DGP, CGI, DGI_mod and UGP have largest AUC and might be slightly more robust. The accuracy of the predictions of afore mentioned seven metrics for the disturbance by glare lies...

  6. Progress of OLED devices with high efficiency at high luminance

    Science.gov (United States)

    Nguyen, Carmen; Ingram, Grayson; Lu, Zhenghong

    2014-03-01

    Organic light emitting diodes (OLEDs) have progressed significantly over the last two decades. For years, OLEDs have been promoted as the next generation technology for flat panel displays and solid-state lighting due to their potential for high energy efficiency and dynamic range of colors. Although high efficiency can readily be obtained at low brightness levels, a significant decline at high brightness is commonly observed. In this report, we will review various strategies for achieving highly efficient phosphorescent OLED devices at high luminance. Specifically, we will provide details regarding the performance and general working principles behind each strategy. We will conclude by looking at how some of these strategies can be combined to produce high efficiency white OLEDs at high brightness.

  7. Shock waves in luminous early-type stars

    International Nuclear Information System (INIS)

    Castor, J.I.

    1986-01-01

    Shock waves that occur in stellar atmospheres have their origin in some hydrodynamic instability of the atmosphere itself or of the stellar interior. In luminous early-type stars these two possibilities are represented by shocks due to an unstable radiatively-accelerated wind, and to shocks generated by the non-radial pulsations known to be present in many or most OB stars. This review is concerned with the structure and development of the shocks in these two cases, and especially with the mass loss that may be due specifically to the shocks. Pulsation-produced shocks are found to be very unfavorable for causing mass loss, owing to the great radiation efficiency that allows them to remain isothermal. The situation regarding radiatively-driven shocks remains unclear, awaiting detailed hydrodynamics calculations. 20 refs., 2 figs

  8. Regulatory role of tetR gene in a novel gene cluster of Acidovorax avenae subsp. avenae RS-1 under oxidative stress

    OpenAIRE

    Liu, He; Yang, Chun-Lan; Ge, Meng-Yu; Ibrahim, Muhammad; Li, Bin; Zhao, Wen-Jun; Chen, Gong-You; Zhu, Bo; Xie, Guan-Lin

    2014-01-01

    Acidovorax avenae subsp. avenae is the causal agent of bacterial brown stripe disease in rice. In this study, we characterized a novel horizontal transfer of a gene cluster, including tetR, on the chromosome of A. avenae subsp. avenae RS-1 by genome-wide analysis. TetR acted as a repressor in this gene cluster and the oxidative stress resistance was enhanced in tetR-deletion mutant strain. Electrophoretic mobility shift assay demonstrated that TetR regulator bound directly to the promoter of ...

  9. Photobacterium kishitanii sp. nov., a luminous marine bacterium symbiotic with deep-sea fishes.

    Science.gov (United States)

    Ast, Jennifer C; Cleenwerck, Ilse; Engelbeen, Katrien; Urbanczyk, Henryk; Thompson, Fabiano L; De Vos, Paul; Dunlap, Paul V

    2007-09-01

    Six representatives of a luminous bacterium commonly found in association with deep, cold-dwelling marine fishes were isolated from the light organs and skin of different fish species. These bacteria were Gram-negative, catalase-positive, and weakly oxidase-positive or oxidase-negative. Morphologically, cells of these strains were coccoid or coccoid-rods, occurring singly or in pairs, and motile by means of polar flagellation. After growth on seawater-based agar medium at 22 degrees C for 18 h, colonies were small, round and white, with an intense cerulean blue luminescence. Analysis of 16S rRNA gene sequence similarity placed these bacteria in the genus Photobacterium. Phylogenetic analysis based on seven housekeeping gene sequences (16S rRNA gene, gapA, gyrB, pyrH, recA, rpoA and rpoD), seven gene sequences of the lux operon (luxC, luxD, luxA, luxB, luxF, luxE and luxG) and four gene sequences of the rib operon (ribE, ribB, ribH and ribA), resolved the six strains as members of the genus Photobacterium and as a clade distinct from other species of Photobacterium. These strains were most closely related to Photobacterium phosphoreum and Photobacterium iliopiscarium. DNA-DNA hybridization values between the designated type strain, Photobacterium kishitanii pjapo.1.1(T), and P. phosphoreum LMG 4233(T), P. iliopiscarium LMG 19543(T) and Photobacterium indicum LMG 22857(T) were 51, 43 and 19 %, respectively. In AFLP analysis, the six strains clustered together, forming a group distinct from other analysed species. The fatty acid C(17 : 0) cyclo was present in these bacteria, but not in P. phosphoreum, P. iliopiscarium or P. indicum. A combination of biochemical tests (arginine dihydrolase and lysine decarboxylase) differentiates these strains from P. phosphoreum and P. indicum. The DNA G+C content of P. kishitanii pjapo.1.1(T) is 40.2 %, and the genome size is approximately 4.2 Mbp, in the form of two circular chromosomes. These strains represent a novel species, for

  10. 10 CFR 30.19 - Self-luminous products containing tritium, krypton-85, or promethium-147.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Self-luminous products containing tritium, krypton-85, or..., krypton-85, or promethium-147. (a) Except for persons who manufacture, process, produce, or initially transfer for sale or distribution self-luminous products containing tritium, krypton-85, or promethium-147...

  11. Clustering Dycom

    KAUST Repository

    Minku, Leandro L.

    2017-10-06

    Background: Software Effort Estimation (SEE) can be formulated as an online learning problem, where new projects are completed over time and may become available for training. In this scenario, a Cross-Company (CC) SEE approach called Dycom can drastically reduce the number of Within-Company (WC) projects needed for training, saving the high cost of collecting such training projects. However, Dycom relies on splitting CC projects into different subsets in order to create its CC models. Such splitting can have a significant impact on Dycom\\'s predictive performance. Aims: This paper investigates whether clustering methods can be used to help finding good CC splits for Dycom. Method: Dycom is extended to use clustering methods for creating the CC subsets. Three different clustering methods are investigated, namely Hierarchical Clustering, K-Means, and Expectation-Maximisation. Clustering Dycom is compared against the original Dycom with CC subsets of different sizes, based on four SEE databases. A baseline WC model is also included in the analysis. Results: Clustering Dycom with K-Means can potentially help to split the CC projects, managing to achieve similar or better predictive performance than Dycom. However, K-Means still requires the number of CC subsets to be pre-defined, and a poor choice can negatively affect predictive performance. EM enables Dycom to automatically set the number of CC subsets while still maintaining or improving predictive performance with respect to the baseline WC model. Clustering Dycom with Hierarchical Clustering did not offer significant advantage in terms of predictive performance. Conclusion: Clustering methods can be an effective way to automatically generate Dycom\\'s CC subsets.

  12. Evaluation of historical museum interior lighting system using fully immersive virtual luminous environment

    Science.gov (United States)

    Navvab, Mojtaba; Bisegna, Fabio; Gugliermetti, Franco

    2013-05-01

    Saint Rocco Museum, a historical building in Venice, Italy is used as a case study to explore the performance of its' lighting system and visible light impact on viewing the large size art works. The transition from threedimensional architectural rendering to the three-dimensional virtual luminance mapping and visualization within a virtual environment is described as an integrated optical method for its application toward preservation of the cultural heritage of the space. Lighting simulation programs represent color as RGB triplets in a devicedependent color space such as ITU-R BT709. Prerequisite for this is a 3D-model which can be created within this computer aided virtual environment. The onsite measured surface luminance, chromaticity and spectral data were used as input to an established real-time indirect illumination and a physically based algorithms to produce the best approximation for RGB to be used as an input to generate the image of the objects. Conversion of RGB to and from spectra has been a major undertaking in order to match the infinite number of spectra to create the same colors that were defined by RGB in the program. The ability to simulate light intensity, candle power and spectral power distributions provide opportunity to examine the impact of color inter-reflections on historical paintings. VR offers an effective technique to quantify the visible light impact on human visual performance under precisely controlled representation of light spectrum that could be experienced in 3D format in a virtual environment as well as historical visual archives. The system can easily be expanded to include other measurements and stimuli.

  13. Effectiveness of Seasonal Malaria Chemoprevention in Children under Ten Years of Age in Senegal: A Stepped-Wedge Cluster-Randomised Trial.

    Directory of Open Access Journals (Sweden)

    Badara Cissé

    2016-11-01

    Full Text Available Seasonal Malaria Chemoprevention (SMC with sulfadoxine-pyrimethamine (SP plus amodiaquine (AQ, given each month during the transmission season, is recommended for children living in areas of the Sahel where malaria transmission is highly seasonal. The recommendation for SMC is currently limited to children under five years of age, but, in many areas of seasonal transmission, the burden in older children may justify extending this age limit. This study was done to determine the effectiveness of SMC in Senegalese children up to ten years of age.SMC was introduced into three districts over three years in central Senegal using a stepped-wedge cluster-randomised design. A census of the population was undertaken and a surveillance system was established to record all deaths and to record all cases of malaria seen at health facilities. A pharmacovigilance system was put in place to detect adverse drug reactions. Fifty-four health posts were randomised. Nine started implementation of SMC in 2008, 18 in 2009, and a further 18 in 2010, with 9 remaining as controls. In the first year of implementation, SMC was delivered to children aged 3-59 months; the age range was then extended for the latter two years of the study to include children up to 10 years of age. Cluster sample surveys at the end of each transmission season were done to measure coverage of SMC and the prevalence of parasitaemia and anaemia, to monitor molecular markers of drug resistance, and to measure insecticide-treated net (ITN use. Entomological monitoring and assessment of costs of delivery in each health post and of community attitudes to SMC were also undertaken. About 780,000 treatments were administered over three years. Coverage exceeded 80% each month. Mortality, the primary endpoint, was similar in SMC and control areas (4.6 and 4.5 per 1000 respectively in children under 5 years and 1.3 and 1.2 per 1000 in children 5-9 years of age; the overall mortality rate ratio [SMC: no SMC

  14. Clustering analysis

    International Nuclear Information System (INIS)

    Romli

    1997-01-01

    Cluster analysis is the name of group of multivariate techniques whose principal purpose is to distinguish similar entities from the characteristics they process.To study this analysis, there are several algorithms that can be used. Therefore, this topic focuses to discuss the algorithms, such as, similarity measures, and hierarchical clustering which includes single linkage, complete linkage and average linkage method. also, non-hierarchical clustering method, which is popular name K -mean method ' will be discussed. Finally, this paper will be described the advantages and disadvantages of every methods

  15. Cluster analysis

    CERN Document Server

    Everitt, Brian S; Leese, Morven; Stahl, Daniel

    2011-01-01

    Cluster analysis comprises a range of methods for classifying multivariate data into subgroups. By organizing multivariate data into such subgroups, clustering can help reveal the characteristics of any structure or patterns present. These techniques have proven useful in a wide range of areas such as medicine, psychology, market research and bioinformatics.This fifth edition of the highly successful Cluster Analysis includes coverage of the latest developments in the field and a new chapter dealing with finite mixture models for structured data.Real life examples are used throughout to demons

  16. Cluster editing

    DEFF Research Database (Denmark)

    Böcker, S.; Baumbach, Jan

    2013-01-01

    . The problem has been the inspiration for numerous algorithms in bioinformatics, aiming at clustering entities such as genes, proteins, phenotypes, or patients. In this paper, we review exact and heuristic methods that have been proposed for the Cluster Editing problem, and also applications......The Cluster Editing problem asks to transform a graph into a disjoint union of cliques using a minimum number of edge modifications. Although the problem has been proven NP-complete several times, it has nevertheless attracted much research both from the theoretical and the applied side...

  17. Independence and interaction of luminance and chromatic contributions to spatial hyperacuity performance.

    Science.gov (United States)

    Cooper, Bonnie; Lee, Barry B

    2014-04-01

    Here we test interactions of luminance and chromatic input to spatial hyperacuity mechanisms. First, we tested alignment of luminance and chromatic gratings matched or mismatched in contrast polarity or grating type. Thresholds with matched gratings were low while all mismatched pairs were elevated. Second, we determined alignment acuity as a function of luminance or chromatic contrast alone or in the presence of constant contrast components of the other type. For in-phase components, performance followed the envelope of the more sensitive mechanism. However, polarity reversals revealed an asymmetric effect for luminance and chromatic conditions, which suggested that luminance can override chromatic mechanisms in hyperacuity; we interpret these findings in the context of spatial mechanisms.

  18. From Globular Clusters to Tidal Dwarfs: Structure Formation in the Tidal Tails of Merging Galaxies

    Science.gov (United States)

    Knierman, Karen A.; Gallagher, Sarah C.; Charlton, Jane C.; Hunsberger, Sally D.; Whitmore, Bradley; Kundu, Arunav; Hibbard, J. E.; Zaritsky, Dennis

    2003-09-01

    Using V and I images obtained with the Wide Field Planetary Camera 2 (WFPC2) of the Hubble Space Telescope, we investigate compact stellar structures within tidal tails. Six regions of tidal debris in the four classic ``Toomre sequence'' mergers: NGC 4038/39 (``Antennae''), NGC 3256, NGC 3921, and NGC 7252 (``Atoms for Peace'') have been studied in order to explore how the star formation depends on the local and global physical conditions. These mergers sample a range of stages in the evolutionary sequence and tails with and without embedded tidal dwarf galaxies. The six tails are found to contain a variety of stellar structures, with sizes ranging from those of globular clusters up to those of dwarf galaxies. From V and I WFPC2 images, we measure the luminosities and colors of the star clusters. NGC 3256 is found to have a large population of blue clusters (0.2<~V-I<~0.9), particularly in its western tail, similar to those found in the inner region of the merger. In contrast, NGC 4038/39 has no clusters in the observed region of the tail, only less luminous point sources likely to be individual stars. NGC 3921 and NGC 7252 have small populations of clusters along their tails. A significant cluster population is clearly associated with the prominent tidal dwarf candidates in the eastern and western tails of NGC 7252. The cluster-rich western tail of NGC 3256 is not distinguished from the others by its dynamical age or by its total H I mass. However, the mergers that have few clusters in the tail all have tidal dwarf galaxies, while NGC 3256 does not have prominent tidal dwarfs. We speculate that star formation in tidal tails may manifest itself either in small structures like clusters along the tail or in large structures such as dwarf galaxies, but not in both. Also, NGC 3256 has the highest star formation rate of the four mergers studied, which may contribute to the high number of star clusters in its tidal tails. Based in part on observations obtained with the

  19. Occupational Clusters.

    Science.gov (United States)

    Pottawattamie County School System, Council Bluffs, IA.

    The 15 occupational clusters (transportation, fine arts and humanities, communications and media, personal service occupations, construction, hospitality and recreation, health occupations, marine science occupations, consumer and homemaking-related occupations, agribusiness and natural resources, environment, public service, business and office…

  20. Fuzzy Clustering

    DEFF Research Database (Denmark)

    Berks, G.; Keyserlingk, Diedrich Graf von; Jantzen, Jan

    2000-01-01

    A symptom is a condition indicating the presence of a disease, especially, when regarded as an aid in diagnosis.Symptoms are the smallest units indicating the existence of a disease. A syndrome on the other hand is an aggregate, set or cluster of concurrent symptoms which together indicate...... and clustering are the basic concerns in medicine. Classification depends on definitions of the classes and their required degree of participant of the elements in the cases' symptoms. In medicine imprecise conditions are the rule and therefore fuzzy methods are much more suitable than crisp ones. Fuzzy c......-mean clustering is an easy and well improved tool, which has been applied in many medical fields. We used c-mean fuzzy clustering after feature extraction from an aphasia database. Factor analysis was applied on a correlation matrix of 26 symptoms of language disorders and led to five factors. The factors...

  1. Cluster generator

    Science.gov (United States)

    Donchev, Todor I [Urbana, IL; Petrov, Ivan G [Champaign, IL

    2011-05-31

    Described herein is an apparatus and a method for producing atom clusters based on a gas discharge within a hollow cathode. The hollow cathode includes one or more walls. The one or more walls define a sputtering chamber within the hollow cathode and include a material to be sputtered. A hollow anode is positioned at an end of the sputtering chamber, and atom clusters are formed when a gas discharge is generated between the hollow anode and the hollow cathode.

  2. Cluster Bulleticity

    OpenAIRE

    Massey, Richard; Kitching, Thomas; Nagai, Daisuke

    2010-01-01

    The unique properties of dark matter are revealed during collisions between clusters of galaxies, such as the bullet cluster (1E 0657−56) and baby bullet (MACS J0025−12). These systems provide evidence for an additional, invisible mass in the separation between the distributions of their total mass, measured via gravitational lensing, and their ordinary ‘baryonic’ matter, measured via its X-ray emission. Unfortunately, the information available from these systems is limited by their rarity. C...

  3. Cluster headache

    OpenAIRE

    Leroux, Elizabeth; Ducros, Anne

    2008-01-01

    Abstract Cluster headache (CH) is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes) of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye). It affects young adults, predominantly males. Prevalence is estimated at 0.5–1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name) in bouts that can occur ...

  4. Elucidating the underlying causes of oral cancer through spatial clustering in high-risk areas of Taiwan with a distinct gender ratio of incidence

    Directory of Open Access Journals (Sweden)

    Chi-Ting Chiang

    2010-05-01

    Full Text Available This study aimed to elucidate whether or not high-risk clusters of oral cancer (OC incidence spatially correlate with the prevalence rates of betel quid chewing (BQC and cigarette smoking (CS in Taiwan. The spatial autocorrelation and potential clusters of OC incidence among the 307 townships and heavy metal content of soil throughout Taiwan were identified using the Anselin’s local Moran test. Additionally, the spatial correlations among the incidence of OC, the prevalence of BQC and CS and heavy metal content of soil were determined based on a comparison of spatial clusters. High-risk OC (Moran’s I = 0.638, P <0.001 clusters were located in central and eastern Taiwan, while “hot spots” of BQC and CS prevalence were located mainly in eastern Taiwan. The distributions of BQC and CS lifestyle factors (P <0.001 were spatially autocorrelated. The “hot spots” of OC largely coincided with the “hot spots” of BQC, except for the Changhua and Yunlin counties, which are located in central Taiwan. However, high soil contents of nickel and chromium (P <0.001 in central Taiwan also coincided with the high-risk areas of OC incidence. In particular, Changhua county has incurred several decades of serious heavy-metal pollution, with inhabitants living in polluted areas having high-risk exposure to these metals. Results of this study suggest that, in addition to BQC and CS, anthropogenic pollution may profoundly impact the complexity of OC aetiology in central Taiwan.

  5. Super-luminous Type II supernovae powered by magnetars

    Science.gov (United States)

    Dessart, Luc; Audit, Edouard

    2018-05-01

    Magnetar power is believed to be at the origin of numerous super-luminous supernovae (SNe) of Type Ic, arising from compact, hydrogen-deficient, Wolf-Rayet type stars. Here, we investigate the properties that magnetar power would have on standard-energy SNe associated with 15-20 M⊙ supergiant stars, either red (RSG; extended) or blue (BSG; more compact). We have used a combination of Eulerian gray radiation-hydrodynamics and non-LTE steady-state radiative transfer to study their dynamical, photometric, and spectroscopic properties. Adopting magnetar fields of 1, 3.5, 7 × 1014 G and rotational energies of 0.4, 1, and 3 × 1051 erg, we produce bolometric light curves with a broad maximum covering 50-150 d and a magnitude of 1043-1044 erg s-1. The spectra at maximum light are analogous to those of standard SNe II-P but bluer. Although the magnetar energy is channelled in equal proportion between SN kinetic energy and SN luminosity, the latter may be boosted by a factor of 10-100 compared to a standard SN II. This influence breaks the observed relation between brightness and ejecta expansion rate of standard Type II SNe. Magnetar energy injection also delays recombination and may even cause re-ionization, with a reversal in photospheric temperature and velocity. Depositing the magnetar energy in a narrow mass shell at the ejecta base leads to the formation of a dense shell at a few 1000 km s-1, which causes a light-curve bump at the end of the photospheric phase. Depositing this energy over a broad range of mass in the inner ejecta, to mimic the effect of multi-dimensional fluid instabilities, prevents the formation of a dense shell and produces an earlier-rising and smoother light curve. The magnetar influence on the SN radiation is generally not visible prior to 20-30 d, during which one may discern a BSG from a RSG progenitor. We propose a magnetar model for the super-luminous Type II SN OGLE-SN14-073.

  6. Evolution of the cluster X-ray luminosity function

    DEFF Research Database (Denmark)

    Mullis, C.R.; Vikhlinin, A.; Henry, J.P.

    2004-01-01

    We report measurements of the cluster X-ray luminosity function out to z = 0.8 based on the final sample of 201 galaxy systems from the 160 Square Degree ROSAT Cluster Survey. There is little evidence for any measurable change in cluster abundance out to z similar to 0.6 at luminosities of less...... than a few times 10(44) h(50)(-2) ergs s(-1) (0.5 - 2.0 keV). However, for 0.6 cluster deficit using integrated number counts...... independently confirm the presence of evolution. Whereas the bulk of the cluster population does not evolve, the most luminous and presumably most massive structures evolve appreciably between z = 0.8 and the present. Interpreted in the context of hierarchical structure formation, we are probing sufficiently...

  7. Month-hour distributions of zenith luminance and diffuse illuminance in Madrid

    International Nuclear Information System (INIS)

    Soler, Alfonso; Gopinathan, Kannam K.; Robledo, Luis; Ruiz, Enrique

    2004-01-01

    Month-hour equal mean zenith luminance contours are obtained from one year of data of zenith luminance measurements for cloudless, overcast and partly cloudy skies and also when the combined data for all sky types are considered. For many hours in different months, the overcast sky luminance values are roughly about three times the cloudless sky luminance values and one and a half times the partly cloudy sky values. The dependence of month-hour equal mean zenith luminance contours on the ratio of global to extraterrestrial illuminance on a horizontal surface is also given. From equal mean zenith luminance contours, the approximate values of the mean zenith luminance for different sky conditions and different hours and months of the year can be easily obtained. Month-hour equal mean diffuse illuminance contours are obtained from diffuse illuminance measurements performed during the period 1992-1998. The dependence on solar altitude of the monthly average hourly values of diffuse illuminance is given and compared to the corresponding one obtained from data for Bet Dagan (Israel)

  8. Mixing of Chromatic and Luminance Retinal Signals in Primate Area V1.

    Science.gov (United States)

    Li, Xiaobing; Chen, Yao; Lashgari, Reza; Bereshpolova, Yulia; Swadlow, Harvey A; Lee, Barry B; Alonso, Jose Manuel

    2015-07-01

    Vision emerges from activation of chromatic and achromatic retinal channels whose interaction in visual cortex is still poorly understood. To investigate this interaction, we recorded neuronal activity from retinal ganglion cells and V1 cortical cells in macaques and measured their visual responses to grating stimuli that had either luminance contrast (luminance grating), chromatic contrast (chromatic grating), or a combination of the two (compound grating). As with parvocellular or koniocellular retinal ganglion cells, some V1 cells responded mostly to the chromatic contrast of the compound grating. As with magnocellular retinal ganglion cells, other V1 cells responded mostly to the luminance contrast and generated a frequency-doubled response to equiluminant chromatic gratings. Unlike magnocellular and parvocellular retinal ganglion cells, V1 cells formed a unimodal distribution for luminance/color preference with a 2- to 4-fold bias toward luminance. V1 cells associated with positive local field potentials in deep layers showed the strongest combined responses to color and luminance and, as a population, V1 cells encoded a diverse combination of luminance/color edges that matched edge distributions of natural scenes. Taken together, these results suggest that the primary visual cortex combines magnocellular and parvocellular retinal inputs to increase cortical receptive field diversity and to optimize visual processing of our natural environment. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. NCOA5 is correlated with progression and prognosis in luminal breast cancer

    International Nuclear Information System (INIS)

    Ye, Xiao-He; Huang, Du-Ping; Luo, Rong-Cheng

    2017-01-01

    Nuclear receptor coactivator 5 (NCOA5) is known to modulate ERα-mediated transcription and has been found to be involved in the progression of several malignancies. However, the potential correlation between NCOA5 and clinical outcome in patients with luminal breast cancer remains unknown. In the present study, we demonstrated that NCOA5 was significantly up-regulated in luminal breast cancer tissues compared with adjacent non-cancerous tissues both in validated cohort and TCGA cohort. Moreover, Kaplan-Meier analysis indicated that patients with high NOCA5 expression had significantly lower overall survival (P = 0.021). Cox regression analysis indicated that the high NOCA5 expression was independent high risk factor as well as old age (>60) and HER-2 expression (P = 0.039; P = 0.003; P = 0.005; respectively). This study provides new insights and evidences that NOCA5 over-expression was significantly correlated with progression and prognosis in luminal breast cancer. However, the precise cellular mechanisms for NOCA5 in luminal breast cancer need to be further explored. - Highlights: • NCOA5 is significantly over-expressed in human luminal breast cancer tissues. • NOCA5 was involved in the progression of luminal breast cancer. • NCOA5 can predict the progression of luminal breast cancer.

  10. Luminal nucleotides are tonic inhibitors of renal tubular transport

    DEFF Research Database (Denmark)

    Leipziger, Jens Georg

    2011-01-01

    PURPOSE OF REVIEW: Extracellular ATP is an essential local signaling molecule in all organ systems. In the kidney, purinergic signaling is involved in an array of functions and this review highlights those of relevance for renal tubular transport. RECENT FINDINGS: Purinergic receptors are express...... discovered as an important signaling compartment in which local purinergic signaling determines an inhibitory tone for renal tubular transport. Blocking components of this system leads to tubular hyper-absorption, volume retention and elevated blood pressure.......PURPOSE OF REVIEW: Extracellular ATP is an essential local signaling molecule in all organ systems. In the kidney, purinergic signaling is involved in an array of functions and this review highlights those of relevance for renal tubular transport. RECENT FINDINGS: Purinergic receptors are expressed...... in all renal tubular segments and their stimulation generally leads to transport inhibition. Recent evidence has identified the tubular lumen as a restricted space for purinergic signaling. The concentrations of ATP in the luminal fluids are sufficiently high to inflict a tonic inhibition of renal...

  11. Green Fluorescent Organic Light Emitting Device with High Luminance

    Directory of Open Access Journals (Sweden)

    Ning YANG

    2014-06-01

    Full Text Available In this work, we fabricated the small molecule green fluorescent bottom-emission organic light emitting device (OLED with the configuration of glass substrate/indium tin oxide (ITO/Copper Phthalocyanine (CuPc 25 nm/ N,N’-di(naphthalen-1-yl-N,N’-diphenyl-benzidine (NPB 45 nm/ tris(8-hydroxyquinoline aluminium (Alq3 60 nm/ Lithium fluoride (LiF 1 nm/Aluminum (Al 100 nm where CuPc and NPB are the hole injection layer and the hole transport layer, respectively. CuPc is introduced in this device to improve carrier injection and efficiency. The experimental results indicated that the turn-on voltage is 2.8 V with a maximum luminance of 23510 cd/m2 at 12 V. The maximum current efficiency and power efficiency are 4.8 cd/A at 100 cd/m2 and 4.2 lm/W at 3 V, respectively. The peak of electroluminance (EL spectrum locates at 530 nm which is typical emission peak of green light. In contrast, the maximum current efficiency and power efficiency of the device without CuPc are only 4.0 cd/A at 100 mA/cm2 and 4.2 lm/W at 3.6 V, respectively.

  12. Cosmological information in the intrinsic alignments of luminous red galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Chisari, Nora Elisa [Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544 (United States); Dvorkin, Cora, E-mail: nchisari@astro.princeton.edu, E-mail: cdvorkin@ias.edu [Institute for Advanced Study, School of Natural Sciences, Einstein Drive, Princeton, NJ 08540 (United States)

    2013-12-01

    The intrinsic alignments of galaxies are usually regarded as a contaminant to weak gravitational lensing observables. The alignment of Luminous Red Galaxies, detected unambiguously in observations from the Sloan Digital Sky Survey, can be reproduced by the linear tidal alignment model of Catelan, Kamionkowski and Blandford (2001) on large scales. In this work, we explore the cosmological information encoded in the intrinsic alignments of red galaxies. We make forecasts for the ability of current and future spectroscopic surveys to constrain local primordial non-Gaussianity and Baryon Acoustic Oscillations (BAO) in the cross-correlation function of intrinsic alignments and the galaxy density field. For the Baryon Oscillation Spectroscopic Survey, we find that the BAO signal in the intrinsic alignments is marginally significant with a signal-to-noise ratio of 1.8 and 2.2 with the current LOWZ and CMASS samples of galaxies, respectively, and increasing to 2.3 and 2.7 once the survey is completed. For the Dark Energy Spectroscopic Instrument and for a spectroscopic survey following the EUCLID redshift selection function, we find signal-to-noise ratios of 12 and 15, respectively. Local type primordial non-Gaussianity, parametrized by f{sub NL} = 10, is only marginally significant in the intrinsic alignments signal with signal-to-noise ratios < 2 for the three surveys considered.

  13. Confirmation of the Luminous Blue Variable Status of MWC 930

    Directory of Open Access Journals (Sweden)

    A. S. Miroshnichenko

    2014-01-01

    Full Text Available We present spectroscopic and photometric observations of the emission-line star MWC 930 (V446 Sct during its long-term optical brightening in 2006–2013. Based on our earlier data we suggested that the object has features found in Luminous Blue Variables (LBV, such as a high luminosity (~3 105 L⊙, a low wind terminal velocity (~140 km s−1, and a tendency to show strong brightness variations (~1 mag over 20 years. For the last ~7 years it has been exhibiting a continuous optical and near-IR brightening along with a change of the emission-line spectrum appearance and cooling of the star’s photosphere. We present the object’s V-band light curve, analyze the spectral variations, and compare the observed properties with those of other recognized Galactic LBVs, such as AG Car and HR Car. Overall we conclude the MWC 930 is a bona fide Galactic LBV that is currently in the middle of an S Dor cycle.

  14. Gemini Near-infrared Spectroscopy of Luminous z~6 Quasars

    DEFF Research Database (Denmark)

    Jiang, Linhua; Fan, Xiaohui; Vestergaard, Marianne

    2007-01-01

    We present Gemini near-infrared spectroscopic observations of six luminous quasars at z=5.8$\\sim$6.3. Five of them were observed using Gemini-South/GNIRS, which provides a simultaneous wavelength coverage of 0.9--2.5 $\\mu$m in cross dispersion mode. The other source was observed in K band...... with Gemini-North/NIRI. We calculate line strengths for all detected emission lines and use their ratios to estimate gas metallicity in the broad-line regions of the quasars. The metallicity is found to be supersolar with a typical value of $\\sim$4 Z_{\\sun}, and a comparison with low-redshift observations...... shows no strong evolution in metallicity up to z$\\sim$6. The FeII/MgII ratio of the quasars is 4.9+/-1.4, consistent with low-redshift measurements. We estimate central BH masses of 10^9 to 10^{10} M_{\\sun} and Eddington luminosity ratios of order unity. We identify two MgII $\\lambda\\lambda$2796...

  15. Notch3 marks clonogenic mammary luminal progenitor cells in vivo.

    Science.gov (United States)

    Lafkas, Daniel; Rodilla, Veronica; Huyghe, Mathilde; Mourao, Larissa; Kiaris, Hippokratis; Fre, Silvia

    2013-10-14

    The identity of mammary stem and progenitor cells remains poorly understood, mainly as a result of the lack of robust markers. The Notch signaling pathway has been implicated in mammary gland development as well as in tumorigenesis in this tissue. Elevated expression of the Notch3 receptor has been correlated to the highly aggressive "triple negative" human breast cancer. However, the specific cells expressing this Notch paralogue in the mammary gland remain unknown. Using a conditionally inducible Notch3-CreERT2(SAT) transgenic mouse, we genetically marked Notch3-expressing cells throughout mammary gland development and followed their lineage in vivo. We demonstrate that Notch3 is expressed in a highly clonogenic and transiently quiescent luminal progenitor population that gives rise to a ductal lineage. These cells are capable of surviving multiple successive pregnancies, suggesting a capacity to self-renew. Our results also uncover a role for the Notch3 receptor in restricting the proliferation and consequent clonal expansion of these cells.

  16. 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

  17. Optimal Solution Volume for Luminal Preservation: A Preclinical Study in Porcine Intestinal Preservation.

    Science.gov (United States)

    Oltean, M; Papurica, M; Jiga, L; Hoinoiu, B; Glameanu, C; Bresler, A; Patrut, G; Grigorie, R; Ionac, M; Hellström, M

    2016-03-01

    Rodent studies suggest that luminal solutions alleviate the mucosal injury and prolong intestinal preservation but concerns exist that excessive volumes of luminal fluid may promote tissue edema. Differences in size, structure, and metabolism between rats and humans require studies in large animals before clinical use. Intestinal procurement was performed in 7 pigs. After perfusion with histidine-tryptophan-ketoglutarate (HTK), 40-cm-long segments were cut and filled with 13.5% polyethylene glycol (PEG) 3350 solution as follows: V0 (controls, none), V1 (0.5 mL/cm), V2 (1 mL/cm), V3 (1.5 mL/cm), and V4 (2 mL/cm). Tissue and luminal solutions were sampled after 8, 14, and 24 hours of cold storage (CS). Preservation injury (Chiu score), the apical membrane (ZO-1, brush-border maltase activity), and the electrolyte content in the luminal solution were studied. In control intestines, 8-hour CS in HTK solution resulted in minimal mucosal changes (grade 1) that progressed to significant subepithelial edema (grade 3) by 24 hours. During this time, a gradual loss in ZO-1 was recorded, whereas maltase activity remained unaltered. Moreover, variable degrees of submucosal edema were observed. Luminal introduction of high volumes (2 mL/mL) of PEG solution accelerated the development of the subepithelial edema and submucosal edema, leading to worse histology. However, ZO-1 was preserved better over time than in control intestines (no luminal solution). Maltase activity was reduced in intestines receiving luminal preservation. Luminal sodium content decreased in time and did not differ between groups. This PEG solution protects the apical membrane and the tight-junction proteins but may favor water absorption and tissue (submucosal) edema, and luminal volumes >2 mL/cm may result in worse intestinal morphology. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. 75 FR 53667 - Space Coast Regional Innovation Cluster Competition

    Science.gov (United States)

    2010-09-01

    ... Coast Regional Innovation Cluster Competition AGENCY: Economic Development Administration (EDA... upcoming availability of funding for the Space Coast Regional Innovation Cluster (RIC) Competition under... economic development initiatives aligned with regional cluster and competitiveness analyses to sustain the...

  19. An Extreme Protocluster of Luminous Dusty Starbursts in the Early Universe

    Science.gov (United States)

    Oteo, I.; Ivison, R. J.; Dunne, L.; Manilla-Robles, A.; Maddox, S.; Lewis, A. J. R.; de Zotti, G.; Bremer, M.; Clements, D. L.; Cooray, A.; Dannerbauer, H.; Eales, S.; Greenslade, J.; Omont, A.; Perez–Fournón, I.; Riechers, D.; Scott, D.; van der Werf, P.; Weiss, A.; Zhang, Z.-Y.

    2018-03-01

    We report the identification of an extreme protocluster of galaxies in the early universe whose core (nicknamed Distant Red Core, DRC, because of its very red color in Herschel SPIRE bands) is formed by at least 10 dusty star-forming galaxies (DSFGs), spectroscopically confirmed to lie at {z}spec}=4.002 via detection of [C I](1–0), 12CO(6–5), 12CO(4–3), 12CO(2–1), and {{{H}}}2{{O}}({2}11{--}{2}02) emission lines with ALMA and ATCA. These DSFGs are distributed over a 260 {kpc}× 310 {kpc} region and have a collective obscured star formation rate (SFR) of ∼ 6500 {M}ȯ {yr}}-1, considerably higher than those seen before in any protocluster at z≳ 4. Most of the star formation is taking place in luminous DSFGs since no Lyα emitters are detected in the protocluster core, apart from a Lyα blob located next to one of the DRC components, extending over 60 {kpc}. The total obscured SFR of the protocluster could rise to {SFR}∼ {{14,400}} {M}ȯ {yr}}-1 if all the members of an overdensity of bright DSFGs discovered around DRC in a wide-field Large APEX BOlometer CAmera 870 μm image are part of the same structure. [C I](1–0) emission reveals that DRC has a total molecular gas mass of at least {M}{{{H}}2}∼ 6.6× {10}11 {M}ȯ , and its total halo mass could be as high as ∼ 4.4× {10}13 {M}ȯ , indicating that it is the likely progenitor of a cluster at least as massive as Coma at z = 0.

  20. Kinetic and radiation processes in cluster plasmas

    International Nuclear Information System (INIS)

    Smirnov, B.M.

    1996-01-01

    The analysis of processes is made for a cluster plasma which is a xenon arc plasma of a high pressure with an admixture of tungsten cluster ions. Because cluster ions emit radiation, this system is a light source which parameters are determined by various processes such as heat release and transport of charged particles in the plasma, radiative processes involving clusters, processes of cluster evaporation and attachment of atoms to it that leads to an equilibrium between clusters and vapor of their atoms, processes of cluster generation, processes of the ionization equilibrium between cluster ions and plasma electrons, transport of cluster ions in the discharge plasma in all directions. These processes govern by properties of a specific cluster plasma under consideration. (author)

  1. CD8+ T Cells Induce Fatal Brainstem Pathology during Cerebral Malaria via Luminal Antigen-Specific Engagement of Brain Vasculature.

    Directory of Open Access Journals (Sweden)

    Phillip A Swanson

    2016-12-01

    Full Text Available Cerebral malaria (CM is a severe complication of Plasmodium falciparum infection that results in thousands of deaths each year, mostly in African children. The in vivo mechanisms underlying this fatal condition are not entirely understood. Using the animal model of experimental cerebral malaria (ECM, we sought mechanistic insights into the pathogenesis of CM. Fatal disease was associated with alterations in tight junction proteins, vascular breakdown in the meninges / parenchyma, edema, and ultimately neuronal cell death in the brainstem, which is consistent with cerebral herniation as a cause of death. At the peak of ECM, we revealed using intravital two-photon microscopy that myelomonocytic cells and parasite-specific CD8+ T cells associated primarily with the luminal surface of CNS blood vessels. Myelomonocytic cells participated in the removal of parasitized red blood cells (pRBCs from cerebral blood vessels, but were not required for the disease. Interestingly, the majority of disease-inducing parasite-specific CD8+ T cells interacted with the lumen of brain vascular endothelial cells (ECs, where they were observed surveying, dividing, and arresting in a cognate peptide-MHC I dependent manner. These activities were critically dependent on IFN-γ, which was responsible for activating cerebrovascular ECs to upregulate adhesion and antigen-presenting molecules. Importantly, parasite-specific CD8+ T cell interactions with cerebral vessels were impaired in chimeric mice rendered unable to present EC antigens on MHC I, and these mice were in turn resistant to fatal brainstem pathology. Moreover, anti-adhesion molecule (LFA-1 / VLA-4 therapy prevented fatal disease by rapidly displacing luminal CD8+ T cells from cerebrovascular ECs without affecting extravascular T cells. These in vivo data demonstrate that parasite-specific CD8+ T cell-induced fatal vascular breakdown and subsequent neuronal death during ECM is associated with luminal, antigen

  2. A comparison of Ki-67 counting methods in luminal Breast Cancer: The Average Method vs. the Hot Spot Method.

    Directory of Open Access Journals (Sweden)

    Min Hye Jang

    Full Text Available In spite of the usefulness of the Ki-67 labeling index (LI as a prognostic and predictive marker in breast cancer, its clinical application remains limited due to variability in its measurement and the absence of a standard method of interpretation. This study was designed to compare the two methods of assessing Ki-67 LI: the average method vs. the hot spot method and thus to determine which method is more appropriate in predicting prognosis of luminal/HER2-negative breast cancers. Ki-67 LIs were calculated by direct counting of three representative areas of 493 luminal/HER2-negative breast cancers using the two methods. We calculated the differences in the Ki-67 LIs (ΔKi-67 between the two methods and the ratio of the Ki-67 LIs (H/A ratio of the two methods. In addition, we compared the performance of the Ki-67 LIs obtained by the two methods as prognostic markers. ΔKi-67 ranged from 0.01% to 33.3% and the H/A ratio ranged from 1.0 to 2.6. Based on the receiver operating characteristic curve method, the predictive powers of the KI-67 LI measured by the two methods were similar (Area under curve: hot spot method, 0.711; average method, 0.700. In multivariate analysis, high Ki-67 LI based on either method was an independent poor prognostic factor, along with high T stage and node metastasis. However, in repeated counts, the hot spot method did not consistently classify tumors into high vs. low Ki-67 LI groups. In conclusion, both the average and hot spot method of evaluating Ki-67 LI have good predictive performances for tumor recurrence in luminal/HER2-negative breast cancers. However, we recommend using the average method for the present because of its greater reproducibility.

  3. A comparison of Ki-67 counting methods in luminal Breast Cancer: The Average Method vs. the Hot Spot Method.

    Science.gov (United States)

    Jang, Min Hye; Kim, Hyun Jung; Chung, Yul Ri; Lee, Yangkyu; Park, So Yeon

    2017-01-01

    In spite of the usefulness of the Ki-67 labeling index (LI) as a prognostic and predictive marker in breast cancer, its clinical application remains limited due to variability in its measurement and the absence of a standard method of interpretation. This study was designed to compare the two methods of assessing Ki-67 LI: the average method vs. the hot spot method and thus to determine which method is more appropriate in predicting prognosis of luminal/HER2-negative breast cancers. Ki-67 LIs were calculated by direct counting of three representative areas of 493 luminal/HER2-negative breast cancers using the two methods. We calculated the differences in the Ki-67 LIs (ΔKi-67) between the two methods and the ratio of the Ki-67 LIs (H/A ratio) of the two methods. In addition, we compared the performance of the Ki-67 LIs obtained by the two methods as prognostic markers. ΔKi-67 ranged from 0.01% to 33.3% and the H/A ratio ranged from 1.0 to 2.6. Based on the receiver operating characteristic curve method, the predictive powers of the KI-67 LI measured by the two methods were similar (Area under curve: hot spot method, 0.711; average method, 0.700). In multivariate analysis, high Ki-67 LI based on either method was an independent poor prognostic factor, along with high T stage and node metastasis. However, in repeated counts, the hot spot method did not consistently classify tumors into high vs. low Ki-67 LI groups. In conclusion, both the average and hot spot method of evaluating Ki-67 LI have good predictive performances for tumor recurrence in luminal/HER2-negative breast cancers. However, we recommend using the average method for the present because of its greater reproducibility.

  4. The ethanol-induced stimulation of rat duodenal mucosal bicarbonate secretion in vivo is critically dependent on luminal Cl-.

    Directory of Open Access Journals (Sweden)

    Anna Sommansson

    Full Text Available Alcohol may induce metabolic and functional changes in gastrointestinal epithelial cells, contributing to impaired mucosal barrier function. Duodenal mucosal bicarbonate secretion (DBS is a primary epithelial defense against gastric acid and also has an important function in maintaining the homeostasis of the juxtamucosal microenvironment. The aim in this study was to investigate the effects of the luminal perfusion of moderate concentrations of ethanol in vivo on epithelial DBS, fluid secretion and paracellular permeability. Under thiobarbiturate anesthesia, a ∼30-mm segment of the proximal duodenum with an intact blood supply was perfused in situ in rats. The effects on DBS, duodenal transepithelial net fluid flux and the blood-to-lumen clearance of 51Cr-EDTA were investigated. Perfusing the duodenum with isotonic solutions of 10% or 15% ethanol-by-volume for 30 min increased DBS in a concentration-dependent manner, while the net fluid flux did not change. Pre-treatment with the CFTR inhibitor CFTRinh172 (i.p. or i.v. did not change the secretory response to ethanol, while removing Cl- from the luminal perfusate abolished the ethanol-induced increase in DBS. The administration of hexamethonium (i.v. but not capsazepine significantly reduced the basal net fluid flux and the ethanol-induced increase in DBS. Perfusing the duodenum with a combination of 1.0 mM HCl and 15% ethanol induced significantly greater increases in DBS than 15% ethanol or 1.0 mM HCl alone but did not influence fluid flux. Our data demonstrate that ethanol induces increases in DBS through a mechanism that is critically dependent on luminal Cl- and partly dependent on enteric neural pathways involving nicotinic receptors. Ethanol and HCl appears to stimulate DBS via the activation of different bicarbonate transporting mechanisms.

  5. SPITZER IRS SPECTRA OF LUMINOUS 8 μm SOURCES IN THE LARGE MAGELLANIC CLOUD: TESTING COLOR-BASED CLASSIFICATIONS

    International Nuclear Information System (INIS)

    Buchanan, Catherine L.; Kastner, Joel H.; Hrivnak, Bruce J.; Sahai, Raghvendra

    2009-01-01

    We present archival Spitzer Infrared Spectrograph (IRS) spectra of 19 luminous 8 μm selected sources in the Large Magellanic Cloud (LMC). The object classes derived from these spectra and from an additional 24 spectra in the literature are compared with classifications based on Two Micron All Sky Survey (2MASS)/MSX (J, H, K, and 8 μm) colors in order to test the 'JHK8' (Kastner et al.) classification scheme. The IRS spectra confirm the classifications of 22 of the 31 sources that can be classified under the JHK8 system. The spectroscopic classification of 12 objects that were unclassifiable in the JHK8 scheme allow us to characterize regions of the color-color diagrams that previously lacked spectroscopic verification, enabling refinements to the JHK8 classification system. The results of these new classifications are consistent with previous results concerning the identification of the most infrared-luminous objects in the LMC. In particular, while the IRS spectra reveal several new examples of asymptotic giant branch (AGB) stars with O-rich envelopes, such objects are still far outnumbered by carbon stars (C-rich AGB stars). We show that Spitzer IRAC/MIPS color-color diagrams provide improved discrimination between red supergiants and oxygen-rich and carbon-rich AGB stars relative to those based on 2MASS/MSX colors. These diagrams will enable the most luminous IR sources in Local Group galaxies to be classified with high confidence based on their Spitzer colors. Such characterizations of stellar populations will continue to be possible during Spitzer's warm mission through the use of IRAC [3.6]-[4.5] and 2MASS colors.

  6. Luminal and basal-like breast cancer cells show increased migration induced by hypoxia, mediated by an autocrine mechanism

    International Nuclear Information System (INIS)

    Voss, Melanie J; Möller, Mischa F; Powe, Desmond G; Niggemann, Bernd; Zänker, Kurt S; Entschladen, Frank

    2011-01-01

    Some breast cancer patients receiving anti-angiogenic treatment show increased metastases, possibly as a result of induced hypoxia. The effect of hypoxia on tumor cell migration was assessed in selected luminal, post-EMT and basal-like breast carcinoma cell lines. Migration was assessed in luminal (MCF-7), post-EMT (MDA-MB-231, MDA-MB-435S), and basal-like (MDA-MB-468) human breast carcinoma cell lines under normal and oxygen-deprived conditions, using a collagen-based assay. Cell proliferation was determined, secreted cytokine and chemokine levels were measured using flow-cytometry and a bead-based immunoassay, and the hypoxic genes HIF-1α and CA IX were assessed using PCR. The functional effect of tumor-cell conditioned medium on the migration of neutrophil granulocytes (NG) was tested. Hypoxia caused increased migratory activity but not proliferation in all tumor cell lines, involving the release and autocrine action of soluble mediators. Conditioned medium (CM) from hypoxic cells induced migration in normoxic cells. Hypoxia changed the profile of released inflammatory mediators according to cell type. Interleukin-8 was produced only by post-EMT and basal-like cell lines, regardless of hypoxia. MCP-1 was produced by MDA-MB-435 and -468 cells, whereas IL-6 was present only in MDA-MB-231. IL-2, TNF-α, and NGF production was stimulated by hypoxia in MCF-7 cells. CM from normoxic and hypoxic MDA-MB-231 and MDA-MB-435S cells and hypoxic MCF-7 cells, but not MDA-MB-468, induced NG migration. Hypoxia increases migration by the autocrine action of released signal substances in selected luminal and basal-like breast carcinoma cell lines which might explain why anti-angiogenic treatment can worsen clinical outcome in some patients

  7. A search for X-ray bright distant clusters of galaxies

    Science.gov (United States)

    Nichol, R. C.; Ulmer, M. P.; Kron, R. G.; Wirth, G. D.; Koo, D. C.

    1994-01-01

    We present the results of a search for X-ray luminous distant clusters of galaxies. We found extended X-ray emission characteristic of a cluster toward two of our candidate clusters of galaxies. They both have a luminosity in the ROSAT bandpass of approximately equals 10(exp 44) ergs/s and a redshift greater than 0.5; thus making them two of the most distant X-ray clusters ever observed. Furthermore, we show that both clusters are optically rich and have a known radio source associated with them. We compare our result with other recent searches for distant X-ray luminous clusters and present a lower limit of 1.2 x 10(exp -7)/cu Mpc for the number density of such high-redshift clusters. This limit is consistent with the expected abundance of such clusters in a standard (b = 2) cold dark matter universe. Finally, our clusters provide important high-redshift targets for further study into the origin and evolution of massive clusters of galaxies.

  8. Support vector machine and fuzzy C-mean clustering-based comparative evaluation of changes in motor cortex electroencephalogram under chronic alcoholism.

    Science.gov (United States)

    Kumar, Surendra; Ghosh, Subhojit; Tetarway, Suhash; Sinha, Rakesh Kumar

    2015-07-01

    In this study, the magnitude and spatial distribution of frequency spectrum in the resting electroencephalogram (EEG) were examined to address the problem of detecting alcoholism in the cerebral motor cortex. The EEG signals were recorded from chronic alcoholic conditions (n = 20) and the control group (n = 20). Data were taken from motor cortex region and divided into five sub-bands (delta, theta, alpha, beta-1 and beta-2). Three methodologies were adopted for feature extraction: (1) absolute power, (2) relative power and (3) peak power frequency. The dimension of the extracted features is reduced by linear discrimination analysis and classified by support vector machine (SVM) and fuzzy C-mean clustering. The maximum classification accuracy (88 %) with SVM clustering was achieved with the EEG spectral features with absolute power frequency on F4 channel. Among the bands, relatively higher classification accuracy was found over theta band and beta-2 band in most of the channels when computed with the EEG features of relative power. Electrodes wise CZ, C3 and P4 were having more alteration. Considering the good classification accuracy obtained by SVM with relative band power features in most of the EEG channels of motor cortex, it can be suggested that the noninvasive automated online diagnostic system for the chronic alcoholic condition can be developed with the help of EEG signals.

  9. Clustering Dycom

    KAUST Repository

    Minku, Leandro L.; Hou, Siqing

    2017-01-01

    baseline WC model is also included in the analysis. Results: Clustering Dycom with K-Means can potentially help to split the CC projects, managing to achieve similar or better predictive performance than Dycom. However, K-Means still requires the number

  10. The First Hyper-Luminous Infrared Galaxy Discovered by WISE

    Science.gov (United States)

    Eisenhardt, Peter R.; Wu, Jingwen; Tsai, Chao-Wei; Assef, Roberto; Benford, Dominic; Blain, Andrew; Bridge, Carrie; Condon, J. J.; Cushing, Michael C.; Cutri, Roc; hide

    2012-01-01

    We report the discovery by the Wide-field Infrared Survey Explorer of the z = 2.452 source WISEJ181417.29+341224.9, the first hyperluminous source found in the WISE survey. WISE 1814+3412 is also the prototype for an all-sky sample of approximately 1000 extremely luminous "W1W2-dropouts" (sources faint or undetected by WISE at 3.4 and 4.6 micrometers and well detected at 12 or 22 micrometers). The WISE data and a 350 micrometers detection give a minimum bolometric luminosity of 3.7 x 10(exp 13) solar luminosity, with approximately 10(exp 14) solar luminosity plausible. Followup images reveal four nearby sources: a QSO and two Lyman Break Galaxies (LBGs) at z = 2.45, and an M dwarf star. The brighter LBG dominates the bolometric emission. Gravitational lensing is unlikely given the source locations and their different spectra and colors. The dominant LBG spectrum indicates a star formation rate approximately 300 solar mass yr(exp -1), accounting for less than or equal to 10 percent of the bolometric luminosity. Strong 22 micrometer emission relative to 350 micrometer implies that warm dust contributes significantly to the luminosity, while cooler dust normally associated with starbursts is constrained by an upper limit at 1.1 mm. Radio emission is approximately 10? above the far-infrared/radio correlation, indicating an active galactic nucleus is present. An obscured AGN combined with starburst and evolved stellar components can account for the observations. If the black hole mass follows the local MBH-bulge mass relation, the implied Eddington ratio is approximately greater than 4. WISE 1814+3412 may be a heavily obscured object where the peak AGN activity occurred prior to the peak era of star formation.

  11. FAR-INFRARED PROPERTIES OF SPITZER-SELECTED LUMINOUS STARBURSTS

    International Nuclear Information System (INIS)

    Kovacs, A.; Omont, A.; Fiolet, N.; Beelen, A.; Dole, H.; Lagache, G.; Lonsdale, C.; Polletta, M.; Greve, T. R.; Borys, C.; Dowell, C. D.; Bell, T. A.; Cox, P.; De Breuck, C.; Farrah, D.; Menten, K. M.; Owen, F.

    2010-01-01

    We present SHARC-2 350 μm data on 20 luminous z ∼ 2 starbursts with S 1.2 m m > 2 mJy from the Spitzer-selected samples of Lonsdale et al. and Fiolet et al. All the sources were detected, with S 350 μ m > 25 mJy for 18 of them. With the data, we determine precise dust temperatures and luminosities for these galaxies using both single-temperature fits and models with power-law mass-temperature distributions. We derive appropriate formulae to use when optical depths are non-negligible. Our models provide an excellent fit to the 6 μm-2 mm measurements of local starbursts. We find characteristic single-component temperatures T 1 ≅ 35.5 ± 2.2 K and integrated infrared (IR) luminosities around 10 12.9±0.1 L sun for the SWIRE-selected sources. Molecular gas masses are estimated at ≅4 x 10 10 M sun , assuming κ 850 μ m = 0.15 m 2 kg -1 and a submillimeter-selected galaxy (SMG)-like gas-to-dust mass ratio. The best-fit models imply ∼>2 kpc emission scales. We also note a tight correlation between rest-frame 1.4 GHz radio and IR luminosities confirming star formation as the predominant power source. The far-IR properties of our sample are indistinguishable from the purely submillimeter-selected populations from current surveys. We therefore conclude that our original selection criteria, based on mid-IR colors and 24 μm flux densities, provides an effective means for the study of SMGs at z ∼ 1.5-2.5.

  12. Endo-luminal grafting for treatment of abdominal aortic aneurysms

    International Nuclear Information System (INIS)

    Fu Weiguo; Wang Yuqi; Chen Fuzhen; Ye Jianrong; Wang Jianhua; Yan Zhiping; Cheng Jiemin

    2000-01-01

    Objective: To evaluate the preliminary clinical results of endovascular procedures for abdominal aortic aneurysms (AAA) in a prospective study. Methods: Six patients (average age 70 years, range 56 to 78) with infrarenal AAA were enrolled in Shanghai Zhongshan hospital from February 1998 to February 1999. Computed tomography and angiography were done in every patient for measurement of the length, diameter, and angulation of the proximal and distal AAA necks, aneurysm sac, and common and external iliac arteries. The average diameter of the aneurysm was 6.3 cm (range 4.6 cm to 8.0 cm). The mean proximal neck diameter was 2.0 cm (range 1.8 cm to 2.2 cm) and proximal neck length was 3.0 cm (range 2.5 cm to 3.5 cm). All patients were treated with the endo-luminal grafting for exclusion of AAA. Results: Two tubular and 4 bifurcated endo-grafts were used. All endo-graft procedures were completed successfully. One patient died of renal failure 72 hours after the procedure because of the prolonged operative time and excessive contrast medium. Aortography after the procedure showed the AAA were excluded by endo-graft and no endo-leak in the proximal or distal connections was detected. The patients could take meal and were ambulatory on the first and second postoperative day, respectively. Clinical success (aneurysm exclusion with no death or endo-leak) at 30 days was 83.3%. In the 24 months follow-up in 5 cases, no migration, endo-leak, and increasing aneurysm size were detected with spiral CT or color Duplex ultrasound. Conclusion: Based on initial results and a short term mean follow-up period of 24 months, the endovascular treatment of AAA with stent-graft system is feasible and safe. Further study will be required to observe the long term result in the exclusion of AAA

  13. Luciferase inactivation in the luminous marine bacterium Vibrio harveyi.

    Science.gov (United States)

    Reeve, C A; Baldwin, T O

    1981-06-01

    Luciferase was rapidly inactivated in stationary-phase cultures of the wild type of the luminous marine bacterium Vibrio harveyi, but was stable in stationary-phase cultures of mutants of V. harveyi that are nonluminous without exogenous aldehyde, termed the aldehyde-deficient mutants. The inactivation in the wild type was halted by cell lysis and was slowed or stopped by O2 deprivation or by addition of KCN and NaF or of chloramphenicol. If KCN and NaF or chloramphenicol were added to a culture before the onset of luciferase inactivation, then luciferase inactivation did not occur. However, if these inhibitors were added after the onset of luciferase inactivation, then luciferase inactivation continued for about 2 to 3 h before the inactivation process stopped. The onset of luciferase inactivation in early stationary-phase cultures of wild-type cell coincided with a slight drop in the intracellular adenosine 5'-triphosphate (ATP) level from a relatively constant log-phase value of 20 pmol of ATP per microgram of soluble cell protein. Addition of KCN and NaF to a culture shortly after this drop in ATP caused a rapid decrease in the ATP level to about 4 pmol of ATP per microgram whereas chloramphenicol added at this same time caused a transient increase in ATP level to about 25 pmol/microgram. The aldehyde-deficient mutant (M17) showed a relatively constant log-phase ATP level identical with that of the wild-type cells, but rather than decreasing in early stationary phase, the ATP level increased to a value twice that in log-phase cells. We suggest that the inactivation of luciferase is dependent on the synthesis of some factor which is produced during stationary phase and is itself unstable, and whose synthesis is blocked by chloramphenicol or cyanide plus fluoride.

  14. The watercolor effect: quantitative evidence for luminance-dependent mechanisms of long-range color assimilation.

    Science.gov (United States)

    Devinck, Frédéric; Delahunt, Peter B; Hardy, Joseph L; Spillmann, Lothar; Werner, John S

    2005-05-01

    When a dark chromatic contour delineating a figure is flanked on the inside by a brighter chromatic contour, the brighter color will spread into the entire enclosed area. This is known as the watercolor effect (WCE). Here we quantified the effect of color spreading using both color-matching and hue-cancellation tasks. Over a wide range of stimulus chromaticities, there was a reliable shift in color appearance that closely followed the direction of the inducing contour. When the contours were equated in luminance, the WCE was still present, but weak. The magnitude of the color spreading increased with increases in luminance contrast between the two contours. Additionally, as the luminance contrast between the contours increased, the chromaticity of the induced color more closely resembled that of the inside contour. The results support the hypothesis that the WCE is mediated by luminance-dependent mechanisms of long-range color assimilation.

  15. Grain formation in the expanding gas flow around cool luminous stars

    International Nuclear Information System (INIS)

    Hasegawa, H.

    1984-01-01

    The existence of solid particles in interstellar space has been revealed by the extinction of starlight in UV, visible and IR. The important sources of interstellar grains are considered to be cool luminous mass loss stars. (author)

  16. Distribution and species composition of planktonic luminous bacteria in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    Distribution of the total viable heterotrophic bacteria and the luminous bacteria in the neretic and oceanic waters of the west coast of India was studied. Counts of viable heterotrophs fluctuated widely, generally with a decrease in their number...

  17. An Assessment of Luminance Imbalance with ANVIS at an Army Helicopter Training Airfield

    National Research Council Canada - National Science Library

    McLean, William

    1997-01-01

    One of the casual factors listed in a 1996 mid-air collision between two Australian Army helicopters in formation was a speculation of possible luminance imbalance between the right and left channels...

  18. Distribution of luminous bacteria and bacterial luminescence in the equatorial region of the Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    to that of seawater, was noticed from the zooplankton samples. This may be due to the autoinduction of luciferase synthesis or the accumulation of autoinducer in the luminous microflora living in close association with zooplankton...

  19. The effects of luminance contrast, colour combinations, font, and search time on brand icon legibility.

    Science.gov (United States)

    Ko, Ya-Hsien

    2017-11-01

    This study explored and identified the effects of luminance contrast, colour combinations, font, and search time on brand icon legibility. A total of 108 participants took part in the experiment. As designed, legibility was measured as a function of the following independent variables: four levels of luminance contrast, sixteen target/background colour combinations, two fonts, and three search times. The results showed that a luminance contrast of 18:1 provided readers with the best legibility. Yellow on black, yellow on blue, and white on blue were the three most legible colour combinations. One of this study's unique findings was that colour combinations may play an even more important role than luminance contrast in the overall legibility of brand icon design. The 12-s search time corresponded with the highest legibility. Arial font was more legible than Times New Roman. These results provide some guidance for brand icon and product advertisement design. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Optimal colour quality of LED clusters based on memory colours.

    Science.gov (United States)

    Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

    2011-03-28

    The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant.

  1. Pulsed flows at the high-altitude cusp poleward boundary, and associated ionospheric convection and particle signatures, during a Cluster - FAST - SuperDARN- Søndrestrøm conjunction under a southwest IMF

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2004-09-01

    Full Text Available Particle and magnetic field observations during a magnetic conjunction Cluster 1-FAST-Søndrestrøm within the field of view of SuperDARN radars on 21 January 2001 allow us to draw a detailed, comprehensive and self-consistent picture at three heights of signatures associated with transient reconnection under a steady south-westerly IMF (clock angle ≈130°. Cluster 1 was outbound through the high altitude (~12RE exterior northern cusp tailward of the bifurcation line (geomagnetic Bx>0 when a solar wind dynamic pressure release shifted the spacecraft into a boundary layer downstream of the cusp. The centerpiece of the investigation is a series of flow bursts observed there by the spacecraft, which were accompanied by strong field perturbations and tailward flow deflections. Analysis shows these to be Alfvén waves. We interpret these flow events as being due to a sequence of reconnected flux tubes, with field-aligned currents in the associated Alfvén waves carrying stresses to the underlying ionosphere, a view strengthened by the other observations. At the magnetic footprint of the region of Cluster flow bursts, FAST observed an ion energy-latitude disperison of the stepped cusp type, with individual cusp ion steps corresponding to individual flow bursts. Simultaneously, the SuperDARN Stokkseyri radar observed very strong poleward-moving radar auroral forms (PMRAFs which were conjugate to the flow bursts at Cluster. FAST was traversing these PMRAFs when it observed the cusp ion steps. The Søndrestrøm radar observed pulsed ionospheric flows (PIFs just poleward of the convection reversal boundary. As at Cluster, the flow was eastward (tailward, implying a coherent eastward (tailward motion of the hypothesized open flux tubes. The joint Søndrestrøm and FAST observations indicate that the open/closed field line boundary was equatorward of the convection reversal boundary by ~2°. The unprecedented accuracy of the conjunction argues strongly

  2. Pulsed flows at the high-altitude cusp poleward boundary, and associated ionospheric convection and particle signatures, during a Cluster - FAST - SuperDARN- Søndrestrøm conjunction under a southwest IMF

    Directory of Open Access Journals (Sweden)

    C. J. Farrugia

    2004-09-01

    Full Text Available Particle and magnetic field observations during a magnetic conjunction Cluster 1-FAST-Søndrestrøm within the field of view of SuperDARN radars on 21 January 2001 allow us to draw a detailed, comprehensive and self-consistent picture at three heights of signatures associated with transient reconnection under a steady south-westerly IMF (clock angle ≈130°. Cluster 1 was outbound through the high altitude (~12RE exterior northern cusp tailward of the bifurcation line (geomagnetic Bx>0 when a solar wind dynamic pressure release shifted the spacecraft into a boundary layer downstream of the cusp. The centerpiece of the investigation is a series of flow bursts observed there by the spacecraft, which were accompanied by strong field perturbations and tailward flow deflections. Analysis shows these to be Alfvén waves. We interpret these flow events as being due to a sequence of reconnected flux tubes, with field-aligned currents in the associated Alfvén waves carrying stresses to the underlying ionosphere, a view strengthened by the other observations. At the magnetic footprint of the region of Cluster flow bursts, FAST observed an ion energy-latitude disperison of the stepped cusp type, with individual cusp ion steps corresponding to individual flow bursts. Simultaneously, the SuperDARN Stokkseyri radar observed very strong poleward-moving radar auroral forms (PMRAFs which were conjugate to the flow bursts at Cluster. FAST was traversing these PMRAFs when it observed the cusp ion steps. The Søndrestrøm radar observed pulsed ionospheric flows (PIFs just poleward of the convection reversal boundary. As at Cluster, the flow was eastward (tailward, implying a coherent eastward (tailward motion of the hypothesized open flux tubes. The joint Søndrestrøm and FAST observations indicate that the open/closed field line boundary was equatorward of the convection reversal boundary by ~2°. The unprecedented accuracy

  3. High luminous flux from single crystal phosphor-converted laser-based white lighting system

    KAUST Repository

    Cantore, Michael; Pfaff, Nathan; Farrell, Robert M.; Speck, James S.; Nakamura, Shuji; DenBaars, Steven P.

    2015-01-01

    efficacy of 86.7 lm/W at 1.4 A and 4.24 V and a peak luminous flux of 1100 lm at 3.0 A and 4.85 V with a luminous efficacy of 75.6 lm/W. Simulations of a pc-LD confirm that the single crystal YAG:Ce sample did not experience thermal quenching at peak LD

  4. Transferable chloramphenicol resistance determinant in luminous Vibrio harveyi from penaeid shrimp Penaeus monodon larvae

    Directory of Open Access Journals (Sweden)

    Thangapalam Jawahar Abraham

    2016-12-01

    Full Text Available Antibiotic-resistant luminous Vibrio harveyi strains isolated from Penaeus monodon larvae were screened for the possession of transferable resistance determinants. All the strains were resistant to chloramphenicol and the determinant coding for chloramphenicol resistance was transferred to Escherichia coli at frequencies of 9.50x10-4 to 4.20x10-4. The results probably suggest the excessive use of chloramphenicol in shrimp hatcheries to combat luminous vibriosis.

  5. Mercury-free electrodeless discharge lamp: effect of xenon pressure and plasma parameters on luminance

    International Nuclear Information System (INIS)

    Nazri Dagang Ahmad; Kondo, Akira; Motomura, Hideki; Jinno, Masafumi

    2009-01-01

    Since there is much concern about environmental preservation, the authors have paid attention to the uses of mercury in lighting application. They have focused on the application of the xenon low-pressure inductively coupled plasma (ICP) discharge in developing cylindrical type mercury-free light sources. ICP can be operated at low filling gas pressures and demonstrates significant potential in producing high density plasma. Xenon pressure was varied from 0.1 to 100 Torr and the lamp luminance was measured. The gas pressure dependence shows an increase in luminance at pressures below 1 Torr. In order to clarify this behaviour, measurement of plasma parameters was carried out using the double probe method and its relation to lamp luminance is discussed. As the gas pressure is decreased (from 1 to 0.01 Torr), the electron temperature increases while the electron density decreases while at the same time the lamp luminance increases. There are several factors that are believed to contribute to the increase in luminance in the very low pressure region. Increases in luminance are considered to be due to the electron-ion recombination process which brings a strong recombination radiation in continuum in the visible region and also due to the effect of stochastic heating.

  6. Nonlinear mapping of the luminance in dual-layer high dynamic range displays

    Science.gov (United States)

    Guarnieri, Gabriele; Ramponi, Giovanni; Bonfiglio, Silvio; Albani, Luigi

    2009-02-01

    It has long been known that the human visual system (HVS) has a nonlinear response to luminance. This nonlinearity can be quantified using the concept of just noticeable difference (JND), which represents the minimum amplitude of a specified test pattern an average observer can discern from a uniform background. The JND depends on the background luminance following a threshold versus intensity (TVI) function. It is possible to define a curve which maps physical luminances into a perceptually linearized domain. This mapping can be used to optimize a digital encoding, by minimizing the visibility of quantization noise. It is also commonly used in medical applications to display images adapting to the characteristics of the display device. High dynamic range (HDR) displays, which are beginning to appear on the market, can display luminance levels outside the range in which most standard mapping curves are defined. In particular, dual-layer LCD displays are able to extend the gamut of luminance offered by conventional liquid crystals towards the black region; in such areas suitable and HVS-compliant luminance transformations need to be determined. In this paper we propose a method, which is primarily targeted to the extension of the DICOM curve used in medical imaging, but also has a more general application. The method can be modified in order to compensate for the ambient light, which can be significantly greater than the black level of an HDR display and consequently reduce the visibility of the details in dark areas.

  7. Near-field visual acuity of pigeons: effects of head location and stimulus luminance.

    Science.gov (United States)

    Hodos, W; Leibowitz, R W; Bonbright, J C

    1976-03-01

    Two pigeons were trained to discriminate a grating stimulus from a blank stimulus of equivalent luminance in a three-key chamber. The stimuli and blanks were presented behind a transparent center key. The procedure was a conditional discrimination in which pecks on the left key were reinforced if the blank had been present behind the center key and pecks on the right key were reinforced if the grating had been present behind the center key. The spatial frequency of the stimuli was varied in each session from four to 29.5 lines per millimeter in accordance with a variation of the method of constant stimuli. The number of lines per millimeter that the subjects could discriminate at threshold was determined from psychometric functions. Data were collected at five values of stimulus luminance ranging from--0.07 to 3.29 log cd/m2. The distance from the stimulus to the anterior nodal point of the eye, which was determined from measurements taken from high-speed motion-picture photographs of three additional pigeons and published intraocular measurements, was 62.0 mm. This distance and the grating detection thresholds were used to calculate the visual acuity of the birds at each level of luminance. Acuity improved with increasing luminance to a peak value of 0.52, which corresponds to a visual angle of 1.92 min, at a luminance of 2.33 log cd/m2. Further increase in luminance produced a small decline in acuity.

  8. Study of luminous emissions associated to electron emissions in radiofrequency cavities

    International Nuclear Information System (INIS)

    Maissa, S.

    1996-01-01

    This study investigates luminous emissions simultaneously to electron emissions and examines their features in order to better understand the field electron emission phenomenon. A RF cavity, operating at room temperature and in pulsed mode, joined to a sophisticated experimental apparatus has been especially developed. The electron and luminous emissions are investigated on cleaned or with metallic, graphitic and dielectric particles contaminated RF surfaces in order to study their influence on these phenomena. During the surface processing, unstable luminous spots glowing during one RF pulse are detected. Their apparition is promoted in the vicinity of the metallic particles or scratches. Two hypotheses could explain their origin: the presence of micro-plasmas associated to electronic explosive emission during processing or the thermal radiation of the melted metal during this emission. Stable luminous spots glowing during several RF pulses are also detected and appear to increase on RF surfaces contaminated with dielectric particles, leading to strong and explosive luminous emissions. Two interpretations are considered: the initiation of surface breakdowns on the dielectric particles or the heating by the RF field at temperatures sufficiently intense to provoke their thermal radiation then their explosion. Finally a superconducting cavity has been adapted to observe luminous spots, which differ from the former ones bu their star shape and could be associated to micro-plasmas, revealed by the starbursts observed on superconducting cavity walls. (author)

  9. Competition between color and luminance for target selection in smooth pursuit and saccadic eye movements.

    Science.gov (United States)

    Spering, Miriam; Montagnini, Anna; Gegenfurtner, Karl R

    2008-11-24

    Visual processing of color and luminance for smooth pursuit and saccadic eye movements was investigated using a target selection paradigm. In two experiments, stimuli were varied along the dimensions color and luminance, and selection of the more salient target was compared in pursuit and saccades. Initial pursuit was biased in the direction of the luminance component whereas saccades showed a relative preference for color. An early pursuit response toward luminance was often reversed to color by a later saccade. Observers' perceptual judgments of stimulus salience, obtained in two control experiments, were clearly biased toward luminance. This choice bias in perceptual data implies that the initial short-latency pursuit response agrees with perceptual judgments. In contrast, saccades, which have a longer latency than pursuit, do not seem to follow the perceptual judgment of salience but instead show a stronger relative preference for color. These substantial differences in target selection imply that target selection processes for pursuit and saccadic eye movements use distinctly different weights for color and luminance stimuli.

  10. LUMINOUS RED GALAXY HALO DENSITY FIELD RECONSTRUCTION AND APPLICATION TO LARGE-SCALE STRUCTURE MEASUREMENTS

    International Nuclear Information System (INIS)

    Reid, Beth A.; Spergel, David N.; Bode, Paul

    2009-01-01

    The nontrivial relationship between observations of galaxy positions in redshift space and the underlying matter field complicates our ability to determine the linear theory power spectrum and extract cosmological information from galaxy surveys. The Sloan Digital Sky Survey (SDSS) luminous red galaxy (LRG) catalog has the potential to place powerful constraints on cosmological parameters. LRGs are bright, highly biased tracers of large-scale structure. However, because they are highly biased, the nonlinear contribution of satellite galaxies to the galaxy power spectrum is large and fingers-of-God (FOGs) are significant. The combination of these effects leads to a ∼10% correction in the underlying power spectrum at k = 0.1 h Mpc -1 and ∼40% correction at k = 0.2 h Mpc -1 in the LRG P(k) analysis of Tegmark et al., thereby compromising the cosmological constraints when this potentially large correction is left as a free parameter. We propose an alternative approach to recovering the matter field from galaxy observations. Our approach is to use halos rather than galaxies to trace the underlying mass distribution. We identify FOGs and replace each FOG with a single halo object. This removes the nonlinear contribution of satellite galaxies, the one-halo term. We test our method on a large set of high-fidelity mock SDSS LRG catalogs and find that the power spectrum of the reconstructed halo density field deviates from the underlying matter power spectrum at the ≤1% level for k ≤ 0.1 h Mpc -1 and ≤4% at k = 0.2 h Mpc -1 . The reconstructed halo density field also removes the bias in the measurement of the redshift space distortion parameter β induced by the FOG smearing of the linear redshift space distortions.

  11. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    The cluster theory attributed to Michael Porter has significantly influenced industrial policies in countries across Europe and North America since the beginning of the 1990s. Institutions such as the EU, OECD and the World Bank and governments in countries such as the UK, France, The Netherlands...... or management. Both the Accelerate Wales and the Accelerate Cluster programmes target this issue by trying to establish networks between companies that can be used to supply knowledge from research institutions to manufacturing companies. The paper concludes that public sector interventions can make...... businesses. The universities were not considered by the participating companies to be important parts of the local business environment and inputs from universities did not appear to be an important source to access knowledge about new product development or new techniques in production, distribution...

  12. Regional Innovation Clusters

    Data.gov (United States)

    Small Business Administration — The Regional Innovation Clusters serve a diverse group of sectors and geographies. Three of the initial pilot clusters, termed Advanced Defense Technology clusters,...

  13. Cluster analysis

    OpenAIRE

    Mucha, Hans-Joachim; Sofyan, Hizir

    2000-01-01

    As an explorative technique, duster analysis provides a description or a reduction in the dimension of the data. It classifies a set of observations into two or more mutually exclusive unknown groups based on combinations of many variables. Its aim is to construct groups in such a way that the profiles of objects in the same groups are relatively homogenous whereas the profiles of objects in different groups are relatively heterogeneous. Clustering is distinct from classification techniques, ...

  14. Uniform Luminous Perovskite Nanofibers with Color-Tunability and Improved Stability Prepared by One-Step Core/Shell Electrospinning.

    Science.gov (United States)

    Tsai, Ping-Chun; Chen, Jung-Yao; Ercan, Ender; Chueh, Chu-Chen; Tung, Shih-Huang; Chen, Wen-Chang

    2018-04-30

    A one-step core/shell electrospinning technique is exploited to fabricate uniform luminous perovskite-based nanofibers, wherein the perovskite and the polymer are respectively employed in the core and the outer shell. Such a coaxial electrospinning technique enables the in situ formation of perovskite nanocrystals, exempting the needs of presynthesis of perovskite quantum dots or post-treatments. It is demonstrated that not only the luminous electrospun nanofibers can possess color-tunability by simply tuning the perovskite composition, but also the grain size of the formed perovskite nanocrystals is largely affected by the perovskite precursor stoichiometry and the polymer solution concentration. Consequently, the optimized perovskite electrospun nanofiber yields a high photoluminescence quantum yield of 30.9%, significantly surpassing the value of its thin-film counterpart. Moreover, owing to the hydrophobic characteristic of shell polymer, the prepared perovskite nanofiber is endowed with a high resistance to air and water. Its photoluminescence intensity remains constant while stored under ambient environment with a relative humidity of 85% over a month and retains intensity higher than 50% of its initial intensity while immersed in water for 48 h. More intriguingly, a white light-emitting perovskite-based nanofiber is successfully fabricated by pairing the orange light-emitting compositional perovskite with a blue light-emitting conjugated polymer. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Microassembly using a Cluster of Paramagnetic Microparticles

    NARCIS (Netherlands)

    Khalil, I.S.M.; Brink, F.V; Sardan Sukas, Ö.; Misra, Sarthak

    2013-01-01

    We use a cluster of paramagnetic microparticles to carry out a wireless two-dimensional microassembly operation. A magnetic-based manipulation system is used to control the motion of the cluster under the influence of the applied magnetic fields. Wireless motion control of the cluster is implemented

  16. Co-clustering models, algorithms and applications

    CERN Document Server

    Govaert, Gérard

    2013-01-01

    Cluster or co-cluster analyses are important tools in a variety of scientific areas. The introduction of this book presents a state of the art of already well-established, as well as more recent methods of co-clustering. The authors mainly deal with the two-mode partitioning under different approaches, but pay particular attention to a probabilistic approach. Chapter 1 concerns clustering in general and the model-based clustering in particular. The authors briefly review the classical clustering methods and focus on the mixture model. They present and discuss the use of different mixture

  17. Evaluation of noncoronary sources of left ventricular perfusion to intercoronary collateral-dependent myocardium due to chronic major vessel occlusion: absent contribution of luminal and extracardiac channels

    International Nuclear Information System (INIS)

    Crystal, G.J.; Downey, H.F.; Bashour, F.A.

    1981-01-01

    Liminal contribution to perfusion of collateral-dependent left ventricular (LV) myocardium was evaluated in six dogs. A portion of LV free wall was rendered collateral-dependent by gradual occlusion of left circumflex artery with Ameroid constrictor. Eight to 10 weeks after implantation of constrictor, measurements of LV myocardial flow were made by left atrial injections of 9-10 micro radioactive microspheres. To measure total collateral flow, microspheres were injected under control conditions, and to measure luminal contribution to collateral flow, microspheres were injected after ligation of right coronary artery during extracorporeal perfusion of left common coronary artery (LCCA) with microsphere-free arterial blood, and during stoppage of flow through LCCA. Under control conditions, myocardial blood flow in collateral-dependent region, 1.01 +/- 0.31 ml/min/gm, was not significantly different from that in normal region, 1.06 +/- 0.32 ml/min/gm. Flow from luminal collateral vessels was negligible (less than 0.005 ml/min/gm) in both collateral-dependent and normal myocardium, and was not affected by stoppage of flow through LCCA. These results indicate that luminal collateral vessels, as well as collateral vessels originating from other noncoronary sources, do not contribute significantly to perfusion of normal or collateral-dependent LV myocardium

  18. Modeling ductal carcinoma in situ: a HER2-Notch3 collaboration enables luminal filling.

    LENUS (Irish Health Repository)

    Pradeep, C-R

    2012-02-16

    A large fraction of ductal carcinoma in situ (DCIS), a non-invasive precursor lesion of invasive breast cancer, overexpresses the HER2\\/neu oncogene. The ducts of DCIS are abnormally filled with cells that evade apoptosis, but the underlying mechanisms remain incompletely understood. We overexpressed HER2 in mammary epithelial cells and observed growth factor-independent proliferation. When grown in extracellular matrix as three-dimensional spheroids, control cells developed a hollow lumen, but HER2-overexpressing cells populated the lumen by evading apoptosis. We demonstrate that HER2 overexpression in this cellular model of DCIS drives transcriptional upregulation of multiple components of the Notch survival pathway. Importantly, luminal filling required upregulation of a signaling pathway comprising Notch3, its cleaved intracellular domain and the transcriptional regulator HES1, resulting in elevated levels of c-MYC and cyclin D1. In line with HER2-Notch3 collaboration, drugs intercepting either arm reverted the DCIS-like phenotype. In addition, we report upregulation of Notch3 in hyperplastic lesions of HER2 transgenic animals, as well as an association between HER2 levels and expression levels of components of the Notch pathway in tumor specimens of breast cancer patients. Therefore, it is conceivable that the integration of the Notch and HER2 signaling pathways contributes to the pathophysiology of DCIS.

  19. Expression of squid iridescence depends on environmental luminance and peripheral ganglion control.

    Science.gov (United States)

    Gonzalez-Bellido, P T; Wardill, T J; Buresch, K C; Ulmer, K M; Hanlon, R T

    2014-03-15

    Squid display impressive changes in body coloration that are afforded by two types of dynamic skin elements: structural iridophores (which produce iridescence) and pigmented chromatophores. Both color elements are neurally controlled, but nothing is known about the iridescence circuit, or the environmental cues, that elicit iridescence expression. To tackle this knowledge gap, we performed denervation, electrical stimulation and behavioral experiments using the long-fin squid, Doryteuthis pealeii. We show that while the pigmentary and iridescence circuits originate in the brain, they are wired differently in the periphery: (1) the iridescence signals are routed through a peripheral center called the stellate ganglion and (2) the iridescence motor neurons likely originate within this ganglion (as revealed by nerve fluorescence dye fills). Cutting the inputs to the stellate ganglion that descend from the brain shifts highly reflective iridophores into a transparent state. Taken together, these findings suggest that although brain commands are necessary for expression of iridescence, integration with peripheral information in the stellate ganglion could modulate the final output. We also demonstrate that squid change their iridescence brightness in response to environmental luminance; such changes are robust but slow (minutes to hours). The squid's ability to alter its iridescence levels may improve camouflage under different lighting intensities.

  20. Modeling the impact of thermal effects on luminous flux maintenance for SSL luminaires

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Lynn [RTI International, Research Triangle Park, NC (United States); Mills, Karmann [RTI International, Research Triangle Park, NC (United States); Lamvik, Michael [RTI International, Research Triangle Park, NC (United States); Solano, Eric [RTI International, Research Triangle Park, NC (United States); Bobashev, Georgiy [RTI International, Research Triangle Park, NC (United States); Perkins, Curtis [RTI International, Research Triangle Park, NC (United States)

    2017-05-30

    Meeting the longevity requirements of solid-state lighting (SSL) devices places extreme demands on the materials and designs that are used in SSL luminaires. Therefore, understanding the aging characteristics of lens, reflectors, and other materials is essential to projecting the long-term performance of LED-based lighting systems. Overlooking these factors at either the design or product specification stage can result in premature failure of the device due to poor luminous flux maintenance and/or excessive chromaticity shifts. This paper describes a methodology for performing accelerated stress testing (AST) on materials intended for use in SSL luminaires. This test methodology, which consists of elevated temperature and humidity conditions, produces accelerated aging data that can be correlated to expected performance under normal luminaire operating conditions. The correlations can then be leveraged to produce models of the changes in the optical properties of key materials including transmittance versus wavelength of lenses and reflectance versus wavelength for housings and other reflectors. This information has been collected into a lumen maintenance decision support tool (LM-DST) and together with user supplied inputs (e.g., expected operation conditions) can provide guidance on lifetime expectations of SSL luminaires. This approach has been applied to a variety of materials commonly found in SSL luminaires including acrylics, polycarbonates, and silicones used for lenses and paints, coatings, films, and composites used for reflectors.

  1. Radiation doses to lungs and whole body from use of tritium in luminous paint industry

    International Nuclear Information System (INIS)

    Rudran, K.

    1988-01-01

    The radiation dose to persons exposed to tritium in the luminous paint industry is reported. The biological half-life of labile tritium is observed to be 7 to 10 days. There is evidence of exposure of lung tissue from tritium labelled polystyrene deposited in the pulmonary region and of soft tissue from organically bound tritium. Delayed excretion of labile tritium in urine following removal of the individuals from tritium handling, presence of tritium in organic constituents of blood and urine, and presence of non-volatile tritium in faecal excretion have been verified. From in vitro studies using fresh bovine serum, solubilisation half-life of tritium from the labelled paint is estimated to be 35 to 70 days after the initial fast clearance. Probable annual doses to the whole body, soft tissue and lungs under the prevailing working conditions have been estimated from the urinary and faecal excretion data. It is revealed that the actual values thus estimated are likely to exceed the values estimated by the conventional technique based on urine analysis for tritiated water. (author)

  2. Relationship of the luminous bacterial symbiont of the Caribbean flashlight fish, Kryptophanaron alfredi (family Anomalopidae) to other luminous bacteria based on bacterial luciferase (luxA) genes.

    Science.gov (United States)

    Haygood, M G

    1990-01-01

    Flashlight fishes (family Anomalopidae) have light organs that contain luminous bacterial symbionts. Although the symbionts have not yet been successfully cultured, the luciferase genes have been cloned directly from the light organ of the Caribbean species, Kryptophanaron alfredi. The goal of this project was to evaluate the relationship of the symbiont to free-living luminous bacteria by comparison of genes coding for bacterial luciferase (lux genes). Hybridization of a lux AB probe from the Kryptophanaron alfredi symbiont to DNAs from 9 strains (8 species) of luminous bacteria showed that none of the strains tested had lux genes highly similar to the symbiont. The most similar were a group consisting of Vibrio harveyi, Vibrio splendidus and Vibrio orientalis. The nucleotide sequence of the luciferase alpha subunit gene luxA) of the Kryptophanaron alfredi symbiont was determined in order to do a more detailed comparison with published luxA sequences from Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi. The hybridization results, sequence comparisons and the mol% G + C of the Kryptophanaron alfredi symbiont luxA gene suggest that the symbiont may be considered as a new species of luminous Vibrio related to Vibrio harveyi.

  3. Statistical Significance for Hierarchical Clustering

    Science.gov (United States)

    Kimes, Patrick K.; Liu, Yufeng; Hayes, D. Neil; Marron, J. S.

    2017-01-01

    Summary Cluster analysis has proved to be an invaluable tool for the exploratory and unsupervised analysis of high dimensional datasets. Among methods for clustering, hierarchical approaches have enjoyed substantial popularity in genomics and other fields for their ability to simultaneously uncover multiple layers of clustering structure. A critical and challenging question in cluster analysis is whether the identified clusters represent important underlying structure or are artifacts of natural sampling variation. Few approaches have been proposed for addressing this problem in the context of hierarchical clustering, for which the problem is further complicated by the natural tree structure of the partition, and the multiplicity of tests required to parse the layers of nested clusters. In this paper, we propose a Monte Carlo based approach for testing statistical significance in hierarchical clustering which addresses these issues. The approach is implemented as a sequential testing procedure guaranteeing control of the family-wise error rate. Theoretical justification is provided for our approach, and its power to detect true clustering structure is illustrated through several simulation studies and applications to two cancer gene expression datasets. PMID:28099990

  4. Computational Design of Clusters for Catalysis

    Science.gov (United States)

    Jimenez-Izal, Elisa; Alexandrova, Anastassia N.

    2018-04-01

    When small clusters are studied in chemical physics or physical chemistry, one perhaps thinks of the fundamental aspects of cluster electronic structure, or precision spectroscopy in ultracold molecular beams. However, small clusters are also of interest in catalysis, where the cold ground state or an isolated cluster may not even be the right starting point. Instead, the big question is: What happens to cluster-based catalysts under real conditions of catalysis, such as high temperature and coverage with reagents? Myriads of metastable cluster states become accessible, the entire system is dynamic, and catalysis may be driven by rare sites present only under those conditions. Activity, selectivity, and stability are highly dependent on size, composition, shape, support, and environment. To probe and master cluster catalysis, sophisticated tools are being developed for precision synthesis, operando measurements, and multiscale modeling. This review intends to tell the messy story of clusters in catalysis.

  5. Intrinsic alignment of redMaPPer clusters: cluster shape-matter density correlation

    Science.gov (United States)

    van Uitert, Edo; Joachimi, Benjamin

    2017-07-01

    We measure the alignment of the shapes of galaxy clusters, as traced by their satellite distributions, with the matter density field using the public redMaPPer catalogue based on Sloan Digital Sky Survey-Data Release 8 (SDSS-DR8), which contains 26 111 clusters up to z ˜ 0.6. The clusters are split into nine redshift and richness samples; in each of them, we detect a positive alignment, showing that clusters point towards density peaks. We interpret the measurements within the tidal alignment paradigm, allowing for a richness and redshift dependence. The intrinsic alignment (IA) amplitude at the pivot redshift z = 0.3 and pivot richness λ = 30 is A_IA^gen=12.6_{-1.2}^{+1.5}. We obtain tentative evidence that the signal increases towards higher richness and lower redshift. Our measurements agree well with results of maxBCG clusters and with dark-matter-only simulations. Comparing our results to the IA measurements of luminous red galaxies, we find that the IA amplitude of galaxy clusters forms a smooth extension towards higher mass. This suggests that these systems share a common alignment mechanism, which can be exploited to improve our physical understanding of IA.

  6. MN112: a new Galactic candidate luminous blue variable

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Fabrika, S.; Sholukhova, O.; Berdnikov, L. N.; Cherepashchuk, A. M.; Zharova, A. V.

    2010-06-01

    We report the discovery of a new Galactic candidate luminous blue variable (cLBV) via detection of an infrared circular nebula and follow-up spectroscopy of its central star. The nebula, MN112, is one of many dozens of circular nebulae detected at 24μm in the Spitzer Space Telescope archival data, whose morphology is similar to that of nebulae associated with known (c)LBVs and related evolved massive stars. Specifically, the core-halo morphology of MN112 bears a striking resemblance to the circumstellar nebula associated with the Galactic cLBV GAL079.29+00.46, which suggests that both nebulae might have a similar origin and that the central star of MN112 is an LBV. The spectroscopy of the central star showed that its spectrum is almost identical to that of the bona fide LBV PCygni, which also supports the LBV classification of the object. To further constrain the nature of MN112, we searched for signatures of possible high-amplitude (>~1mag) photometric variability of the central star using archival and newly obtained photometric data covering a 45-yr period. We found that the B magnitude of the star was constant within error margins, while in the I band the star brightened by ~=0.4mag during the last 17 yr. Although the non-detection of large photometric variability leads us to use the prefix `candidate' in the classification of MN112, we remind the readers that the long-term photometric stability is not unusual for genuine LBVs and that the brightness of PCygni remained relatively stable during the last three centuries. Partially based on observations collected at the German-Spanish Astronomical Center, Calar Alto, jointly operated by the Max-Planck-Institut für Astronomie Heidelberg and the Instituto de Astrofísica de Andalucía (CSIC). E-mail: vgvaram@mx.iki.rssi.ru (VVG); akniazev@saao.ac.za (AYK); fabrika@sao.ru (SF); olga@sao.ru (OS); berdnik@sai.msu.ru (LNB); cher@sai.msu.ru (AMC); alla@sai.msu.ru (AVZ)

  7. The impact of retail-sector delivery of artemether-lumefantrine on malaria treatment of children under five in Kenya: a cluster randomized controlled trial.

    Directory of Open Access Journals (Sweden)

    Beth P Kangwana

    2011-05-01

    Full Text Available It has been proposed that artemisinin-based combination therapy (ACT be subsidised in the private sector in order to improve affordability and access. This study in western Kenya aimed to evaluate the impact of providing subsidized artemether-lumefantrine (AL through retail providers on the coverage of prompt, effective antimalarial treatment for febrile children aged 3-59 months.We used a cluster-randomized, controlled design with nine control and nine intervention sublocations, equally distributed across three districts in western Kenya. Cross-sectional household surveys were conducted before and after the delivery of the intervention. The intervention comprised provision of subsidized packs of paediatric ACT to retail outlets, training of retail outlet staff, and community awareness activities. The primary outcome was defined as the proportion of children aged 3-59 months reporting fever in the past 2 weeks who started treatment with AL on the same day or following day of fever onset. Data were collected using structured questionnaires and analyzed based on cluster-level summaries, comparing control to intervention arms, while adjusting for other covariates. Data were collected on 2,749 children in the target age group at baseline and 2,662 at follow-up. 29% of children experienced fever within 2 weeks before the interview. At follow-up, the percentage of children receiving AL on the day of fever or the following day had risen by 14.6% points in the control arm (from 5.3% [standard deviation (SD: 3.2%] to 19.9% [SD: 10.0%] and 40.2% points in the intervention arm (from 4.7% [SD: 3.4%] to 44.9% [SD: 11.7%]. The percentage of children receiving AL was significantly greater in the intervention arm at follow-up, with a difference between the arms of 25.0% points (95% confidence interval [CI]: 14.1%, 35.9%; unadjusted p = 0.0002, adjusted p = 0.0001. No significant differences were observed between arms in the proportion of caregivers who sought

  8. Chandra X-ray observations of the hyper-luminous infrared galaxy IRAS F15307+3252

    Science.gov (United States)

    Hlavacek-Larrondo, J.; Gandhi, P.; Hogan, M. T.; Gendron-Marsolais, M.-L.; Edge, A. C.; Fabian, A. C.; Russell, H. R.; Iwasawa, K.; Mezcua, M.

    2017-01-01

    Hyper-luminous infrared galaxies (HyLIRGs) lie at the extreme luminosity end of the IR galaxy population with LIR > 1013 L⊙. They are thought to be closer counterparts of the more distant sub-millimeter galaxies, and should therefore be optimal targets to study the most massive systems in formation. We present deep Chandra observations of IRAS F15307+3252 (100 ks), a classical HyLIRG located at z = 0.93 and hosting a radio-loud AGN (L1.4 GHz ˜ 3.5 × 1025 W Hz-1). The Chandra images reveal the presence of extended (r = 160 kpc), asymmetric X-ray emission in the soft 0.3-2.0 keV band that has no radio counterpart. We therefore argue that the emission is of thermal origin originating from a hot intragroup or intracluster medium virializing in the potential. We find that the temperature (˜2 keV) and bolometric X-ray luminosity (˜3 × 1043 erg s-1) of the gas follow the expected LX-ray-T correlation for groups and clusters, and that the gas has a remarkably short cooling time of 1.2 Gyr. In addition, VLA radio observations reveal that the galaxy hosts an unresolved compact steep-spectrum (CSS) source, most likely indicating the presence of a young radio source similar to 3C186. We also confirm that the nucleus is dominated by a redshifted 6.4 keV Fe Kα line, strongly suggesting that the AGN is Compton-thick. Finally, Hubble images reveal an overdensity of galaxies and sub-structure in the galaxy that correlates with soft X-ray emission. This could be a snapshot view of on-going groupings expected in a growing cluster environment. IRAS F15307+3252 might therefore be a rare example of a group in the process of transforming into a cluster.

  9. Shaping Globular Clusters with Black Holes

    Science.gov (United States)

    Kohler, Susanna

    2018-03-01

    How many black holes lurk within the dense environments of globular clusters, and how do these powerful objects shape the properties of the cluster around them? One such cluster, NGC 3201, is now helping us to answer these questions.Hunting Stellar-Mass Black HolesSince the detection of merging black-hole binaries by the Laser Interferometer Gravitational-Wave Observatory (LIGO), the dense environments of globular clusters have received increasing attention as potential birthplaces of these compact binary systems.The central region of the globular star cluster NGC 3201, as viewed by Hubble. The black hole is in orbit with the star marked by the blue circle. [NASA/ESA]In addition, more and more stellar-mass black-hole candidates have been observed within globular clusters, lurking in binary pairs with luminous, non-compact companions. The most recent of these detections, found in the globular cluster NGC 3201, stands alone as the first stellar-mass black hole candidate discovered via radial velocity observations: the black holes main-sequence companion gave away its presence via a telltale wobble.Now a team of scientists led by Kyle Kremer (CIERA and Northwestern University) is using models of this system to better understand the impact that black holes might have on their host clusters.A Model ClusterThe relationship between black holes and their host clusters is complicated. Though the cluster environment can determine the dynamical evolution of the black holes, the retention rate of black holes in a globular cluster (i.e., how many remain in the cluster when they are born as supernovae, rather than being kicked out during the explosion) influences how the host cluster evolves.Kremer and collaborators track this complex relationship by modeling the evolution of a cluster similar to NGC 3201 with a Monte Carlo code. The code incorporates physics relevant to the evolution of black holes and black-hole binaries in globular clusters, such as two-body relaxation

  10. Herd Clustering: A synergistic data clustering approach using collective intelligence

    KAUST Repository

    Wong, Kachun

    2014-10-01

    Traditional data mining methods emphasize on analytical abilities to decipher data, assuming that data are static during a mining process. We challenge this assumption, arguing that we can improve the analysis by vitalizing data. In this paper, this principle is used to develop a new clustering algorithm. Inspired by herd behavior, the clustering method is a synergistic approach using collective intelligence called Herd Clustering (HC). The novel part is laid in its first stage where data instances are represented by moving particles. Particles attract each other locally and form clusters by themselves as shown in the case studies reported. To demonstrate its effectiveness, the performance of HC is compared to other state-of-the art clustering methods on more than thirty datasets using four performance metrics. An application for DNA motif discovery is also conducted. The results support the effectiveness of HC and thus the underlying philosophy. © 2014 Elsevier B.V.

  11. In Silico Analysis of Gene Expression Network Components Underlying Pigmentation Phenotypes in the Python Identified Evolutionarily Conserved Clusters of Transcription Factor Binding Sites

    Directory of Open Access Journals (Sweden)

    Kristopher J. L. Irizarry

    2016-01-01

    Full Text Available Color variation provides the opportunity to investigate the genetic basis of evolution and selection. Reptiles are less studied than mammals. Comparative genomics approaches allow for knowledge gained in one species to be leveraged for use in another species. We describe a comparative vertebrate analysis of conserved regulatory modules in pythons aimed at assessing bioinformatics evidence that transcription factors important in mammalian pigmentation phenotypes may also be important in python pigmentation phenotypes. We identified 23 python orthologs of mammalian genes associated with variation in coat color phenotypes for which we assessed the extent of pairwise protein sequence identity between pythons and mouse, dog, horse, cow, chicken, anole lizard, and garter snake. We next identified a set of melanocyte/pigment associated transcription factors (CREB, FOXD3, LEF-1, MITF, POU3F2, and USF-1 that exhibit relatively conserved sequence similarity within their DNA binding regions across species based on orthologous alignments across multiple species. Finally, we identified 27 evolutionarily conserved clusters of transcription factor binding sites within ~200-nucleotide intervals of the 1500-nucleotide upstream regions of AIM1, DCT, MC1R, MITF, MLANA, OA1, PMEL, RAB27A, and TYR from Python bivittatus. Our results provide insight into pigment phenotypes in pythons.

  12. A view of the H-band light-element chemical patterns in globular clusters under the AGB self-enrichment scenario

    Science.gov (United States)

    Dell'Agli, F.; García-Hernández, D. A.; Ventura, P.; Mészáros, Sz; Masseron, T.; Fernández-Trincado, J. G.; Tang, B.; Shetrone, M.; Zamora, O.; Lucatello, S.

    2018-04-01

    We discuss the self-enrichment scenario by asymptotic giant branch (AGB) stars for the formation of multiple populations in globular clusters (GCs) by analysing data set of giant stars observed in nine Galactic GCs, covering a wide range of metallicities and for which the simultaneous measurements of C, N, O, Mg, Al, and Si are available. To this aim, we calculated six sets of AGB models, with the same chemical composition as the stars belonging to the first generation of each GC. We find that the AGB yields can reproduce the set of observations available, not only in terms of the degree of contamination shown by stars in each GC but, more important, also the observed trend with metallicity, which agrees well with the predictions from AGB evolution modelling. While further observational evidences are required to definitively fix the main actors in the pollution of the interstellar medium from which new generation of stars formed in GCs, the present results confirm that the gas ejected by stars of mass in the range 4 M_{⊙} ≤ M ≤ 8 M_{⊙} during the AGB phase share the same chemical patterns traced by stars in GCs.

  13. The lack of luminous matter in the poles

    Science.gov (United States)

    Shatsova, R. B.; Anisimova, G. B.

    2010-01-01

    Many RR Lyral type stars, globular clusters and dwarf galaxus of Local Group are localized in the thin oval envelopes around the holes. 12 ovals over ▵b = 30° are in the zone of Polar Ring of the Galaxy l = (97° and 277°)+/-30°. IRAS sources on λ = 60° and 100 mμ have roughly similar distribution. These small formations partly resemble the cells of large scale of the Universe and maybe have the identical nature. It is possible that the observable picture is formed by the dark matter.

  14. DACH1: its role as a classifier of long term good prognosis in luminal breast cancer.

    Directory of Open Access Journals (Sweden)

    Desmond G Powe

    Full Text Available BACKGROUND: Oestrogen receptor (ER positive (luminal tumours account for the largest proportion of females with breast cancer. Theirs is a heterogeneous disease presenting clinical challenges in managing their treatment. Three main biological luminal groups have been identified but clinically these can be distilled into two prognostic groups in which Luminal A are accorded good prognosis and Luminal B correlate with poor prognosis. Further biomarkers are needed to attain classification consensus. Machine learning approaches like Artificial Neural Networks (ANNs have been used for classification and identification of biomarkers in breast cancer using high throughput data. In this study, we have used an artificial neural network (ANN approach to identify DACH1 as a candidate luminal marker and its role in predicting clinical outcome in breast cancer is assessed. MATERIALS AND METHODS: A reiterative ANN approach incorporating a network inferencing algorithm was used to identify ER-associated biomarkers in a publically available cDNA microarray dataset. DACH1 was identified in having a strong influence on ER associated markers and a positive association with ER. Its clinical relevance in predicting breast cancer specific survival was investigated by statistically assessing protein expression levels after immunohistochemistry in a series of unselected breast cancers, formatted as a tissue microarray. RESULTS: Strong nuclear DACH1 staining is more prevalent in tubular and lobular breast cancer. Its expression correlated with ER-alpha positive tumours expressing PgR, epithelial cytokeratins (CK18/19 and 'luminal-like' markers of good prognosis including FOXA1 and RERG (p<0.05. DACH1 is increased in patients showing longer cancer specific survival and disease free interval and reduced metastasis formation (p<0.001. Nuclear DACH1 showed a negative association with markers of aggressive growth and poor prognosis. CONCLUSION: Nuclear DACH1 expression

  15. BRIGHTEST CLUSTER GALAXIES AND CORE GAS DENSITY IN REXCESS CLUSTERS

    International Nuclear Information System (INIS)

    Haarsma, Deborah B.; Leisman, Luke; Donahue, Megan; Bruch, Seth; Voit, G. Mark; Boehringer, Hans; Pratt, Gabriel W.; Pierini, Daniele; Croston, Judith H.; Arnaud, Monique

    2010-01-01

    We investigate the relationship between brightest cluster galaxies (BCGs) and their host clusters using a sample of nearby galaxy clusters from the Representative XMM-Newton Cluster Structure Survey. The sample was imaged with the Southern Observatory for Astrophysical Research in R band to investigate the mass of the old stellar population. Using a metric radius of 12 h -1 kpc, we found that the BCG luminosity depends weakly on overall cluster mass as L BCG ∝ M 0.18±0.07 cl , consistent with previous work. We found that 90% of the BCGs are located within 0.035 r 500 of the peak of the X-ray emission, including all of the cool core (CC) clusters. We also found an unexpected correlation between the BCG metric luminosity and the core gas density for non-cool-core (non-CC) clusters, following a power law of n e ∝ L 2.7±0.4 BCG (where n e is measured at 0.008 r 500 ). The correlation is not easily explained by star formation (which is weak in non-CC clusters) or overall cluster mass (which is not correlated with core gas density). The trend persists even when the BCG is not located near the peak of the X-ray emission, so proximity is not necessary. We suggest that, for non-CC clusters, this correlation implies that the same process that sets the central entropy of the cluster gas also determines the central stellar density of the BCG, and that this underlying physical process is likely to be mergers.

  16. Calculating Cluster Masses via the Sunyaev-Zel'dovich Effect

    Science.gov (United States)

    Lindley, Ashley; Landry, D.; Bonamente, M.; Joy, M.; Bulbul, E.; Carlstrom, J. E.; Culverhouse, T. L.; Gralla, M.; Greer, C.; Hawkins, D.; Lamb, J. W.; Leitch, E. M.; Marrone, D. P.; Miller, A.; Mroczkowski, T.; Muchovej, S.; Plagge, T.; Woody, D.

    2012-05-01

    Accurate measurements of the total mass of galaxy clusters are key for measuring the cluster mass function and therefore investigating the evolution of the universe. We apply two new methods to measure cluster masses for five galaxy clusters contained within the Brightest Cluster Sample (BCS), an X-ray luminous statistically complete sample of 35 clusters at z=0.15-0.30. These methods distinctively use only observations of the Sunyaev-Zel'dovich (SZ) effect, for which the brightness is redshift independent. At the low redshifts of the BCS, X-ray observations can easily be used to determine cluster masses, providing convenient calibrators for our SZ mass calculations. These clusters have been observed with the Sunyaev-Zel'dovich Array (SZA), an interferometer that is part of the Combined Array for Research in Millimeter-wave Astronomy (CARMA) that has been optimized for accurate measurement of the SZ effect in clusters of galaxies at 30 GHz. One method implements a scaling relation that relates the integrated pressure, Y, as determined by the SZ observations to the mass of the cluster calculated via optical weak lensing. The second method makes use of the Virial theorem to determine the mass given the integrated pressure of the cluster. We find that masses calculated utilizing these methods within a radius r500 are consistent with X-ray masses, calculated by manipulating the surface brightness and temperature data within the same radius, thus concluding that these are viable methods for the determination of cluster masses via the SZ effect. We present preliminary results of our analysis for five galaxy clusters.

  17. Exposure of luminous marine bacteria to low-dose gamma-radiation.

    Science.gov (United States)

    Kudryasheva, N S; Petrova, A S; Dementyev, D V; Bondar, A A

    2017-04-01

    The study addresses biological effects of low-dose gamma-radiation. Radioactive 137 Cs-containing particles were used as model sources of gamma-radiation. Luminous marine bacterium Photobacterium phosphoreum was used as a bioassay with the bioluminescent intensity as the physiological parameter tested. To investigate the sensitivity of the bacteria to the low-dose gamma-radiation exposure (≤250 mGy), the irradiation conditions were varied as follows: bioluminescence intensity was measured at 5, 10, and 20°С for 175, 100, and 47 h, respectively, at different dose rates (up to 4100 μGy/h). There was no noticeable effect of gamma-radiation at 5 and 10°С, while the 20°С exposure revealed authentic bioluminescence inhibition. The 20°С results of gamma-radiation exposure were compared to those for low-dose alpha- and beta-radiation exposures studied previously under comparable experimental conditions. In contrast to ionizing radiation of alpha and beta types, gamma-emission did not initiate bacterial bioluminescence activation (adaptive response). As with alpha- and beta-radiation, gamma-emission did not demonstrate monotonic dose-effect dependencies; the bioluminescence inhibition efficiency was found to be related to the exposure time, while no dose rate dependence was found. The sequence analysis of 16S ribosomal RNA gene did not reveal a mutagenic effect of low-dose gamma radiation. The exposure time that caused 50% bioluminescence inhibition was suggested as a test parameter for radiotoxicity evaluation under conditions of chronic low-dose gamma irradiation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Robustness of radiomic breast features of benign lesions and luminal A cancers across MR magnet strengths

    Science.gov (United States)

    Whitney, Heather M.; Drukker, Karen; Edwards, Alexandra; Papaioannou, John; Giger, Maryellen L.

    2018-02-01

    Radiomics features extracted from breast lesion images have shown potential in diagnosis and prognosis of breast cancer. As clinical institutions transition from 1.5 T to 3.0 T magnetic resonance imaging (MRI), it is helpful to identify robust features across these field strengths. In this study, dynamic contrast-enhanced MR images were acquired retrospectively under IRB/HIPAA compliance, yielding 738 cases: 241 and 124 benign lesions imaged at 1.5 T and 3.0 T and 231 and 142 luminal A cancers imaged at 1.5 T and 3.0 T, respectively. Lesions were segmented using a fuzzy C-means method. Extracted radiomic values for each group of lesions by cancer status and field strength of acquisition were compared using a Kolmogorov-Smirnov test for the null hypothesis that two groups being compared came from the same distribution, with p-values being corrected for multiple comparisons by the Holm-Bonferroni method. Two shape features, one texture feature, and three enhancement variance kinetics features were found to be potentially robust. All potentially robust features had areas under the receiver operating characteristic curve (AUC) statistically greater than 0.5 in the task of distinguishing between lesion types (range of means 0.57-0.78). The significant difference in voxel size between field strength of acquisition limits the ability to affirm more features as robust or not robust according to field strength alone, and inhomogeneities in static field strength and radiofrequency field could also have affected the assessment of kinetic curve features as robust or not. Vendor-specific image scaling could have also been a factor. These findings will contribute to the development of radiomic signatures that use features identified as robust across field strength.

  19. Glossiness and perishable food quality: visual freshness judgment of fish eyes based on luminance distribution.

    Science.gov (United States)

    Murakoshi, Takuma; Masuda, Tomohiro; Utsumi, Ken; Tsubota, Kazuo; Wada, Yuji

    2013-01-01

    Previous studies have reported the effects of statistics of luminance distribution on visual freshness perception using pictures which included the degradation process of food samples. However, these studies did not examine the effect of individual differences between the same kinds of food. Here we elucidate whether luminance distribution would continue to have a significant effect on visual freshness perception even if visual stimuli included individual differences in addition to the degradation process of foods. We took pictures of the degradation of three fishes over 3.29 hours in a controlled environment, then cropped square patches of their eyes from the original images as visual stimuli. Eleven participants performed paired comparison tests judging the visual freshness of the fish eyes at three points of degradation. Perceived freshness scores (PFS) were calculated using the Bradley-Terry Model for each image. The ANOVA revealed that the PFS for each fish decreased as the degradation time increased; however, the differences in the PFS between individual fish was larger for the shorter degradation time, and smaller for the longer degradation time. A multiple linear regression analysis was conducted in order to determine the relative importance of the statistics of luminance distribution of the stimulus images in predicting PFS. The results show that standard deviation and skewness in luminance distribution have a significant influence on PFS. These results show that even if foodstuffs contain individual differences, visual freshness perception and changes in luminance distribution correlate with degradation time.

  20. Luminance gradient at object borders communicates object location to the human oculomotor system.

    Science.gov (United States)

    Kilpeläinen, Markku; Georgeson, Mark A

    2018-01-25

    The locations of objects in our environment constitute arguably the most important piece of information our visual system must convey to facilitate successful visually guided behaviour. However, the relevant objects are usually not point-like and do not have one unique location attribute. Relatively little is known about how the visual system represents the location of such large objects as visual processing is, both on neural and perceptual level, highly edge dominated. In this study, human observers made saccades to the centres of luminance defined squares (width 4 deg), which appeared at random locations (8 deg eccentricity). The phase structure of the square was manipulated such that the points of maximum luminance gradient at the square's edges shifted from trial to trial. The average saccade endpoints of all subjects followed those shifts in remarkable quantitative agreement. Further experiments showed that the shifts were caused by the edge manipulations, not by changes in luminance structure near the centre of the square or outside the square. We conclude that the human visual system programs saccades to large luminance defined square objects based on edge locations derived from the points of maximum luminance gradients at the square's edges.

  1. The effects of luminance contribution from large fields to chromatic visual evoked potentials.

    Science.gov (United States)

    Skiba, Rafal M; Duncan, Chad S; Crognale, Michael A

    2014-02-01

    Though useful from a clinical and practical standpoint uniform, large-field chromatic stimuli are likely to contain luminance contributions from retinal inhomogeneities. Such contribution can significantly influence psychophysical thresholds. However, the degree to which small luminance artifacts influence the chromatic VEP has been debated. In particular, claims have been made that band-pass tuning observed in chromatic VEPs result from luminance intrusion. However, there has been no direct evidence presented to support these claims. Recently, large-field isoluminant stimuli have been developed to control for intrusion from retinal inhomogeneities with particular regard to the influence of macular pigment. We report here the application of an improved version of these full-field stimuli to directly test the influence of luminance intrusion on the temporal tuning of the chromatic VEP. Our results show that band-pass tuning persists even when isoluminance is achieved throughout the extent of the stimulus. In addition, small amounts of luminance intrusion affect neither the shape of the temporal tuning function nor the major components of the VEP. These results support the conclusion that the chromatic VEP can depart substantially from threshold psychophysics with regard to temporal tuning and that obtaining a low-pass function is not requisite evidence of selective chromatic activation in the VEP. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Accurate method for luminous transmittance and signal detection quotients measurements in sunglasses lenses

    Science.gov (United States)

    Loureiro, A. D.; Gomes, L. M.; Ventura, L.

    2018-02-01

    The international standard ISO 12312-1 proposes transmittance tests that quantify how dark sunglasses lenses are and whether or not they are suitable for driving. To perform these tests a spectrometer is required. In this study, we present and analyze theoretically an accurate alternative method for performing these measurements using simple components. Using three LEDs and a four-channel sensor we generated weighting functions similar to the standard ones for luminous and traffic lights transmittances. From 89 sunglasses lens spectroscopy data, we calculated luminous transmittance and signal detection quotients using our obtained weighting functions and the standard ones. Mean-difference Tukey plots were used to compare the results. All tested sunglasses lenses were classified in the right category and correctly as suitable or not for driving. The greatest absolute errors for luminous transmittance and red, yellow, green and blue signal detection quotients were 0.15%, 0.17, 0.06, 0.04 and 0.18, respectively. This method will be used in a device capable to perform transmittance tests (visible, traffic lights and ultraviolet (UV)) according to the standard. It is important to measure rightly luminous transmittance and relative visual attenuation quotients to report correctly whether or not sunglasses are suitable for driving. Moreover, standard UV requirements depend on luminous transmittance.

  3. Characteristics of estrogen-induced peroxidase in mouse uterine luminal fluid

    International Nuclear Information System (INIS)

    Jellinck, P.H.; Newbold, R.R.; McLachlan, J.A.

    1991-01-01

    Peroxidase activity in the uterine luminal fluid of mice treated with diethylstilbestrol was measured by the guaiacol assay and also by the formation of 3H2O from [2-3H]estradiol. In the radiometric assay, the generation of 3H2O and 3H-labeled water-soluble products was dependent on H2O2 (25 to 100 microM), with higher concentrations being inhibitory. Tyrosine or 2,4-dichlorophenol strongly enhanced the reaction catalyzed either by the luminal fluid peroxidase or the enzyme in the CaCl2 extract of the uterus, but decreased the formation of 3H2O from [2-3H]estradiol by lactoperoxidase in the presence of H2O2 (80 microM). NADPH, ascorbate, and cytochrome c inhibited both luminal fluid and uterine tissue peroxidase activity to the same extent, while superoxide dismutase showed a marginal activating effect. Lactoferrin, a major protein component of uterine luminal fluid, was shown not to contribute to its peroxidative activity, and such an effect by prostaglandin synthase was also ruled out. However, it was not possible to exclude eosinophil peroxidase, brought to the uterus after estrogen stimulation, as being the source of peroxidase activity in uterine luminal fluid

  4. Computer simulation of defect cluster

    Energy Technology Data Exchange (ETDEWEB)

    Kuramoto, Eiichi [Kyushu Univ., Kasuga, Fukuoka (Japan). Research Inst. for Applied Mechanics

    1996-04-01

    In order to elucidate individual element process of various defects and defect clusters of used materials under irradiation environments, interatomic potential with reliability was investigated. And for comparison with experimental results, it is often required to adopt the temperature effect and to investigate in details mechanism of one dimensional motion of micro conversion loop and so forth using the molecular dynamic (MD) method. Furthermore, temperature effect is also supposed for stable structure of defects and defect clusters, and many problems relating to alloy element are also remained. And, simulation on photon life at the defects and defect clusters thought to be important under comparison with equipment can also be supposed an improvement of effectiveness due to relation to theses products. In this paper, some topics in such flow was extracted to explain them. In particular, future important problems will be potential preparation of alloy, structure, dynamic behavior and limited temperature of intralattice atomic cluster. (G.K.)

  5. Luminous carbon star in Canis Major OB1

    International Nuclear Information System (INIS)

    Herbst, W.; Racine, R.; Richer, H.B.

    1977-01-01

    The fact that W CMa illuminates a reflection nebula is used to argue that it is spatially associated with the CMa OBl/CMa Rl complex. An apparent cluster around the carbon star is found to consist primarly of field stars, although a few probable late B-type members of CMa OBl are identified. On the basis of its likely association with CMa OBl, a luminosity for W CMa is derived. The values M/sub v/ = -4.7 and M/sub bol/ = - 7.2 are found. It seems likely that the progenitor of W CMa was an O-type member of CMa OBl with a mass greater than 20 M/sub solar/ and a main-sequence lifetime less than 3 x 10 6 years

  6. Di-, tri-, tetranuclear clusters and polymeric cadmium compounds: Syntheses, structures and fluorescent properties with various linking fashions and high stability of orotates under the condition of strong bases

    International Nuclear Information System (INIS)

    Li Xing; Bing Yue; Zha Meiqin; Wang Dongjie; Han Lei; Cao Rong

    2011-01-01

    Assembly reactions of orotic acid (H 3 dtpc ) and CdCl 2 .2.5H 2 O or CdSO 4 .8H 2 O yielded four new cadmium compounds {[Cd(H 2 dtpc)(phen)(H 2 O) 2 ].(H 2 dtpc).4H 2 O} 2 (1: solution reaction, pH=4-5, in addition of phen), [Cd 3 (dtpc) 2 (phen) 5 ].13H 2 O (2: hydrothermal reaction, initial pH=14, final pH=7.5), [Cd(Hdtpc)(H 2 O) 3 ] 4 (3: solution reaction, initial pH=6.5, final pH=6.0), {[Cd(Hdtpc)(phen)(H 2 O)].H 2 O} n (4: hydrothermal reaction, initial pH=8; final pH=6.5), respectively. Compounds 1-4 have been characterized by IR, thermogravimetric analyses (TGA), photoluminescence analyses, single-crystal and powder X-ray diffraction (PXRD). Compound 1 is a binuclear, 2 is a trinuclear, 3 is a tetranuclear structure, and 4 possesses one-dimensional chain framework, respectively, in which the orotate ligands show seven different linking fashions in 1-4. The orotate ligands as trivalence anions are observed in the formation of orotate-compounds, in which the orotates show high stability under the extreme condition of strong basic solution, high temperature and pressure. - Graphical abstract: Assembly of orotic acid and Cd(II) salts result in four new compounds under different reaction conditions, the compounds possess strong photoluminescence emissions and high thermal stability. Highlights: → Four Cd-compounds were prepared from orotic acid under different crystallization systems. → The orotates as trivalence anions displayed high stability under extremely conditions. → The orotates displayed various connection modes in the compounds. → The strong photoluminescence emissions have been observed in the compounds.

  7. Nuclear clustering - a cluster core model study

    International Nuclear Information System (INIS)

    Paul Selvi, G.; Nandhini, N.; Balasubramaniam, M.

    2015-01-01

    Nuclear clustering, similar to other clustering phenomenon in nature is a much warranted study, since it would help us in understanding the nature of binding of the nucleons inside the nucleus, closed shell behaviour when the system is highly deformed, dynamics and structure at extremes. Several models account for the clustering phenomenon of nuclei. We present in this work, a cluster core model study of nuclear clustering in light mass nuclei

  8. Understanding the nature of luminous red galaxies (LRGs): connecting LRGs to central and satellite subhaloes

    Science.gov (United States)

    Masaki, Shogo; Hikage, Chiaki; Takada, Masahiro; Spergel, David N.; Sugiyama, Naoshi

    2013-08-01

    We develop a novel abundance matching method to construct a mock catalogue of luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS), using catalogues of haloes and subhaloes in N-body simulations for a Λ-dominated cold dark matter model. Motivated by observations suggesting that LRGs are passively evolving, massive early-type galaxies with a typical age ≳5 Gyr, we assume that simulated haloes at z = 2 (z2-halo) are progenitors for LRG-host subhaloes observed today, and we label the most tightly bound particles in each progenitor z2-halo as LRG `stars'. We then identify the subhaloes containing these stars to z = 0.3 (SDSS redshift) in descending order of the masses of z2-haloes until the comoving number density of the matched subhaloes becomes comparable to the measured number density of SDSS LRGs, bar{n}_LRG=10^{-4} h^3 Mpc^{-3}. Once the above prescription is determined, our only free parameter is the number density of haloes identified at z = 2 and this parameter is fixed to match the observed number density at z = 0.3. By tracing subsequent merging and assembly histories of each progenitor z2-halo, we can directly compute, from the mock catalogue, the distributions of central and satellite LRGs and their internal motions in each host halo at z = 0.3. While the SDSS LRGs are galaxies selected by the magnitude and colour cuts from the SDSS images and are not necessarily a stellar-mass-selected sample, our mock catalogue reproduces a host of SDSS measurements: the halo occupation distribution for central and satellite LRGs, the projected autocorrelation function of LRGs, the cross-correlation of LRGs with shapes of background galaxies (LRG-galaxy weak lensing) and the non-linear redshift-space distortion effect, the Finger-of-God effect, in the angle-averaged redshift-space power spectrum. The mock catalogue generated based on our method can be used for removing or calibrating systematic errors in the cosmological interpretation of LRG clustering

  9. Supersymmetry for nuclear cluster systems

    International Nuclear Information System (INIS)

    Levai, G.; Cseh, J.; Van Isacker, P.

    2001-01-01

    A supersymmetry scheme is proposed for nuclear cluster systems. The bosonic sector of the superalgebra describes the relative motion of the clusters, while its fermionic sector is associated with their internal structure. An example of core+α configurations is discussed in which the core is a p-shell nucleus and the underlying superalgebra is U(4/12). The α-cluster states of the nuclei 20 Ne and 19 F are analysed and correlations between their spectra, electric quadrupole transitions, and one-nucleon transfer reactions are interpreted in terms of U(4/12) supersymmetry. (author)

  10. Galaxies in x-ray selected clusters and groups in Dark Energy Survey Data I: Stellar mass growth of bright central galaxies since Z similar to 1.2

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Y.; Miller, C.; McKay, T.; Rooney, P.; Evrard, A. E.; Romer, A. K.; Perfecto, R.; Song, J; Desai, S.; Mohr, J. J.; Vikram, V.

    2016-01-10

    Using the science verification data of the Dark Energy Survey for a new sample of 106 X-ray selected clusters and groups, we study the stellar mass growth of bright central galaxies (BCGs) since redshift z similar to 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into an analysis of a redshift-dependent BCG-cluster mass relation, m(*) proportional to (M-200/1.5 x 10(14)M(circle dot))(0.24 +/- 0.08)(1+z)(-0.19 +/- 0.34), and compare the observed relation to the model prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of M-200,M-z = 10(13.8)M(circle dot); at z = 1.0: m(*, BCG) appears to have grown by 0.13 +/- 0.11 dex, in tension at the similar to 2.5 sigma significance level with the 0.40 dex growth rate expected from the semi-analytic model. We show that the build-up of extended intracluster light after z = 1.0 may alleviate this tension in BCG growth rates.

  11. Effect of trapped electrons on the transient current density and luminance of organic light-emitting diode

    Science.gov (United States)

    Lee, Jiun-Haw; Chen, Chia-Hsun; Lin, Bo-Yen; Shih, Yen-Chen; Lin, King-Fu; Wang, Leeyih; Chiu, Tien-Lung; Lin, Chi-Feng

    2018-04-01

    Transient current density and luminance from an organic light-emitting diode (OLED) driven by voltage pulses were investigated. Waveforms with different repetition rate, duty cycle, off-period, and on-period were used to study the injection and transport characteristics of electron and holes in an OLED under pulse operation. It was found that trapped electrons inside the emitting layer (EML) and the electron transporting layer (ETL) material, tris(8-hydroxyquinolate)aluminum (Alq3) helped for attracting the holes into the EML/ETL and reducing the driving voltage, which was further confirmed from the analysis of capacitance-voltage and displacement current measurement. The relaxation time and trapped filling time of the trapped electrons in Alq3 layer were ~200 µs and ~600 µs with 6 V pulse operation, respectively.

  12. The time course of color- and luminance-based salience effects.

    Directory of Open Access Journals (Sweden)

    Isabel C Dombrowe

    2010-11-01

    Full Text Available Salient objects in the visual field attract our attention. Recent work in the orientation domain has shown that the effects of the relative salience of two singleton elements on covert visual attention disappear over time. The present study aims to investigate how salience derived from color and luminance differences affects covert selection. In two experiments, observers indicated the location of a probe which was presented at different stimulus-onset-asynchronies after the presentation of a singleton display containing a homogeneous array of oriented lines and two distinct color singletons (Experiment 1 or luminance singletons (Experiment 2. The results show that relative singleton salience from luminance and color differences, just as from orientation differences, affects covert visual attention in a brief time span after stimulus onset. The mere presence of an object, however, can affect covert attention for a longer time span regardless of salience.

  13. Luminance and image quality analysis of an organic electroluminescent panel with a patterned microlens array attachment

    International Nuclear Information System (INIS)

    Lin, Hoang Yan; Chen, Kuan-Yu; Ho, Yu-Hsuan; Fang, Jheng-Hao; Hsu, Sheng-Chih; Lee, Jiun-Haw; Lin, Jia-Rong; Wei, Mao-Kuo

    2010-01-01

    Luminance and image quality observed from the normal direction of a commercial 2.0 inch panel based on organic electroluminescence (OEL) technology attached to regular and patterned microlens array films (MAFs) were studied and analyzed. When applying the regularly arranged MAF on the panel, a luminance enhancement of 23% was observed, accompanied by a reduction of the image quality index as low as 74%. By removing the microlenses on the emitting areas, the patterned MAF enhances the luminance efficiency of the OEL by 52% keeping the image quality index of the display as high as 94%, due to the effective light extraction in the glass substrate being less than the critical angle. 3D simulation based on a ray-tracing model was also established to investigate the spatial distribution of light rays radiated from an OEL pixel with different microstructures which showed consistent results with the experimental results

  14. Observations of Ultra-Luminous X-ray Sources, and Implications

    Science.gov (United States)

    Colbert, E. J. M.

    2004-05-01

    I will review observations of Ultra-Luminous X-ray Sources (ULXs; Lx > 1E39 erg/s), in particular those observations that have helped reveal the nature of these curious objects. Some recent observations suggest that ULXs are a heterogenous class. Although ULX phenomenology is not fully understood, I will present some examples from the (possibly overlapping) sub-classes. Since ULXs are the most luminous objects in starburst galaxies, they, and ``normal'' luminous black-hole high-mass X-ray binaries are intimately tied to the global galaxian X-ray-star-formation connection. Further work is needed to understand how ULXs form, and how they are associated with the putative population of intermediate-mass black holes.

  15. Environmental radioactive monitoring, evaluation and protection in luminous workshops of a factory

    International Nuclear Information System (INIS)

    Dai Hanbin; Xiang Ming; Tan Jianzu

    2009-01-01

    Fluorescent technique is often used to display instrumental indicator in the dark environment. Luminous workshops of a factory smear and depict the glassware by means of fluorescent power with adulterated radioactive matter. Because of adulterated radioactive matters such as 226 Ra, 40 K emit alpha-ray,beta-ray and gamma-ray, while they decay spontaneously, and high dose or cumulative radiation can damage human body in different degrees. Therefore, any radioactive damage to human body caused by over-safety dose should be prevented strictly during the working. To ensure health and safety of working staff in luminous workshop and the public, it is necessary to regularly have radioactive monitoring and evaluation to luminous workshop and its surrounding environment. Through the environment radioactive monitoring, the authors analyze its environmental radioactive level,and try to find out the possible problems so as to propose some protective measures for personal health. (authors)

  16. High-protein diet modifies colonic microbiota and luminal environment but not colonocyte metabolism in the rat model: the increased luminal bulk connection.

    Science.gov (United States)

    Liu, Xinxin; Blouin, Jean-Marc; Santacruz, Arlette; Lan, Annaïg; Andriamihaja, Mireille; Wilkanowicz, Sabina; Benetti, Pierre-Henri; Tomé, Daniel; Sanz, Yolanda; Blachier, François; Davila, Anne-Marie

    2014-08-15

    High-protein diets are used for body weight reduction, but consequences on the large intestine ecosystem are poorly known. Here, rats were fed for 15 days with either a normoproteic diet (NP, 14% protein) or a hyperproteic-hypoglucidic isocaloric diet (HP, 53% protein). Cecum and colon were recovered for analysis. Short- and branched-chain fatty acids, as well as lactate, succinate, formate, and ethanol contents, were markedly increased in the colonic luminal contents of HP rats (P diet, whereas the amount of butyrate in feces was increased (P diet consumption allows maintenance in the luminal butyrate concentration and thus its metabolism in colonocytes despite modified microbiota composition and increased substrate availability. Copyright © 2014 the American Physiological Society.

  17. Optimal combination of illusory and luminance-defined 3-D surfaces: A role for ambiguity.

    Science.gov (United States)

    Hartle, Brittney; Wilcox, Laurie M; Murray, Richard F

    2018-04-01

    The shape of the illusory surface in stereoscopic Kanizsa figures is determined by the interpolation of depth from the luminance edges of adjacent inducing elements. Despite ambiguity in the position of illusory boundaries, observers reliably perceive a coherent three-dimensional (3-D) surface. However, this ambiguity may contribute additional uncertainty to the depth percept beyond what is expected from measurement noise alone. We evaluated the intrinsic ambiguity of illusory boundaries by using a cue-combination paradigm to measure the reliability of depth percepts elicited by stereoscopic illusory surfaces. We assessed the accuracy and precision of depth percepts using 3-D Kanizsa figures relative to luminance-defined surfaces. The location of the surface peak was defined by illusory boundaries, luminance-defined edges, or both. Accuracy and precision were assessed using a depth-discrimination paradigm. A maximum likelihood linear cue combination model was used to evaluate the relative contribution of illusory and luminance-defined signals to the perceived depth of the combined surface. Our analysis showed that the standard deviation of depth estimates was consistent with an optimal cue combination model, but the points of subjective equality indicated that observers consistently underweighted the contribution of illusory boundaries. This systematic underweighting may reflect a combination rule that attributes additional intrinsic ambiguity to the location of the illusory boundary. Although previous studies show that illusory and luminance-defined contours share many perceptual similarities, our model suggests that ambiguity plays a larger role in the perceptual representation of illusory contours than of luminance-defined contours.

  18. SPECIFIC CHARACTERISTICS OF BRAIN METASTASIZING IN PATIENTS WITH LUMINAL SUBTYPE OF BREAST CANCER

    Directory of Open Access Journals (Sweden)

    A. S. Balkanov

    2016-01-01

    Full Text Available Background: More than half of female patients with breast cancer are diagnosed with a  luminal subtype of the disease; however, specific characteristics of its metastases to the brain have been not well studied, unlike those of HER2 positive and triple negative subtypes. Aim: A  comparative analysis of characteristics of metastatic brain lesions in patients with luminal breast cancer. Materials and methods: The time from surgery for breast cancer to the first recurrence and to metastatic brain lesions (assessed by contrast-enhanced MRI imaging was measured in 41 patients with luminal subtype of breast cancer (median age, 49.5±9.6  years, depending on a  diameter of the primary tumor and numbers of involved axillary lymph nodes. Results: The time interval to occurrence of brain metastases in luminal subtype of breast cancer is not associated with the size of the tumor. If≥4  axillary lymph nodes are involved (N2–3, brain metastases are identified much earlier (p<0.05 than in patients with N0–1 (34.5±23.9 months and 62.7±50 months, respectively. Neither the size nor the involvement of axillary lymph nodes has any impact on the rates of metastatic lesion to the brain during the first recurrence. Conclusion: Brain metastases occur at a much shorter time in those patients of luminal subtype of breast cancer who have metastases in≥4  axillary lymph nodes. Brain metastases develop in 50% of patients with the first recurrence of the luminal subtype of breast cancer.

  19. Gene cluster statistics with gene families.

    Science.gov (United States)

    Raghupathy, Narayanan; Durand, Dannie

    2009-05-01

    Identifying genomic regions that descended from a common ancestor is important for understanding the function and evolution of genomes. In distantly related genomes, clusters of homologous gene pairs are evidence of candidate homologous regions. Demonstrating the statistical significance of such "gene clusters" is an essential component of comparative genomic analyses. However, currently there are no practical statistical tests for gene clusters that model the influence of the number of homologs in each gene family on cluster significance. In this work, we demonstrate empirically that failure to incorporate gene family size in gene cluster statistics results in overestimation of significance, leading to incorrect conclusions. We further present novel analytical methods for estimating gene cluster significance that take gene family size into account. Our methods do not require complete genome data and are suitable for testing individual clusters found in local regions, such as contigs in an unfinished assembly. We consider pairs of regions drawn from the same genome (paralogous clusters), as well as regions drawn from two different genomes (orthologous clusters). Determining cluster significance under general models of gene family size is computationally intractable. By assuming that all gene families are of equal size, we obtain analytical expressions that allow fast approximation of cluster probabilities. We evaluate the accuracy of this approximation by comparing the resulting gene cluster probabilities with cluster probabilities obtained by simulating a realistic, power-law distributed model of gene family size, with parameters inferred from genomic data. Surprisingly, despite the simplicity of the underlying assumption, our method accurately approximates the true cluster probabilities. It slightly overestimates these probabilities, yielding a conservative test. We present additional simulation results indicating the best choice of parameter values for data

  20. Feasibility and pilot study of the effects of microfinance on mortality and nutrition in children under five amongst the very poor in India: study protocol for a cluster randomized controlled trial.

    Science.gov (United States)

    Ojha, Shalini; Szatkowski, Lisa; Sinha, Ranjeet; Yaron, Gil; Fogarty, Andrew; Allen, Stephen; Choudhary, Sunil; Smyth, Alan R

    2014-07-23

    The United Nations Millennium Development Goals include targets for the health of children under five years old. Poor health is linked to poverty and microfinance initiatives are economic interventions that may improve health by breaking the cycle of poverty. However, there is a lack of reliable evidence to support this. In addition, microfinance schemes may have adverse effects on health, for example due to increased indebtedness. Rojiroti UK and the Centre for Promoting Sustainable Livelihood run an innovative microfinance scheme that provides microcredit via women's self-help groups (SHGs). This pilot study, conducted in rural Bihar (India), will establish whether it is feasible to collect anthropometric and mortality data on children under five years old and to conduct a limited cluster randomized trial of the Rojiroti intervention. We have designed a cluster randomized trial in which participating tolas (small communities within villages) will be randomized to either receive early (SHGs and microfinance at baseline) or late intervention (SHGs and microfinance after 18 months). Using predesigned questionnaires, demographic, and mortality data for the last year and information about participating mothers and their children will be collected and the weight, height, and mid upper arm circumference (MUAC) of children will be measured at baseline and at 18 months. The late intervention group will establish SHGs and microfinance support at this point and data collection will be repeated at 36 months.The primary outcome measure will be the mean weight for height z-score of children under five years old in the early and late intervention tolas at 18 months. Secondary outcome measures will be the mortality rate, mean weight for age, height for age, prevalence of underweight, stunting, and wasting among children under five years of age. Despite economic progress, marked inequalities in child health persist in India and Bihar is one of the worst affected states. There

  1. Immunoelectron microscopic localisation of keratin and luminal epithelial antigens in normal and neoplastic urothelium.

    Science.gov (United States)

    Wilson, P D; Nathrath, W B; Trejdosiewicz, L K

    1982-01-01

    Immunoelectron microscope cytochemistry was carried out on 2% paraformaldehyde fixed, 50 mu sections of normal urothelium and bladder carcinoma cells in culture using antisera raised in rabbits to human 40-63 000 MW epidermal "broad spectrum" keratin and calf urothelial "luminal epithelial antigen" (aLEA) Both the unconjugated and indirect immunoperoxidase-DAB techniques were used before routine embedding. The localisation of both keratin and luminal epithelial antigen (LEA) was similar in normal and neoplastic cells and reaction product was associated not only with tonofilaments but also lining membrane vesicles and on fine filaments in the cytoplasmic ground substance.

  2. Prognostic Significance of Progesterone Receptor–Positive Tumor Cells Within Immunohistochemically Defined Luminal A Breast Cancer

    Science.gov (United States)

    Prat, Aleix; Cheang, Maggie Chon U.; Martín, Miguel; Parker, Joel S.; Carrasco, Eva; Caballero, Rosalía; Tyldesley, Scott; Gelmon, Karen; Bernard, Philip S.; Nielsen, Torsten O.; Perou, Charles M.

    2013-01-01

    Purpose Current immunohistochemical (IHC)-based definitions of luminal A and B breast cancers are imperfect when compared with multigene expression-based assays. In this study, we sought to improve the IHC subtyping by examining the pathologic and gene expression characteristics of genomically defined luminal A and B subtypes. Patients and Methods Gene expression and pathologic features were collected from primary tumors across five independent cohorts: British Columbia Cancer Agency (BCCA) tamoxifen-treated only, Grupo Español de Investigación en Cáncer de Mama 9906 trial, BCCA no systemic treatment cohort, PAM50 microarray training data set, and a combined publicly available microarray data set. Optimal cutoffs of percentage of progesterone receptor (PR) –positive tumor cells to predict survival were derived and independently tested. Multivariable Cox models were used to test the prognostic significance. Results Clinicopathologic comparisons among luminal A and B subtypes consistently identified higher rates of PR positivity, human epidermal growth factor receptor 2 (HER2) negativity, and histologic grade 1 in luminal A tumors. Quantitative PR gene and protein expression were also found to be significantly higher in luminal A tumors. An empiric cutoff of more than 20% of PR-positive tumor cells was statistically chosen and proved significant for predicting survival differences within IHC-defined luminal A tumors independently of endocrine therapy administration. Finally, no additional prognostic value within hormonal receptor (HR) –positive/HER2-negative disease was observed with the use of the IHC4 score when intrinsic IHC-based subtypes were used that included the more than 20% PR-positive tumor cells and vice versa. Conclusion Semiquantitative IHC expression of PR adds prognostic value within the current IHC-based luminal A definition by improving the identification of good outcome breast cancers. The new proposed IHC-based definition of luminal A

  3. The most luminous type 2 Active Galactic Nuclei of the Swift/ BAT catalog : Are they different?

    Science.gov (United States)

    Baer, Rudolf Erik; Oh, Kyuseok; Koss, Michael; Wong, Ivy; Schawinski, Kevin

    2018-01-01

    We present an analysis of the most luminous obscured AGN of the Swift/BAT 70 month catalog, which is based on an all-sky survey in the 14 – 195 keV energy range. This survey identified 838 AGN. Excluding Blazars and AGN close ( |gb| BAT 70 month catalog and from a specific observation campaign in order to analyze the relationship of their luminosity to black hole mass and their Eddington ratios. We discuss whether these most luminous type 2 AGN have common characteristics, which differentiate them from all the type 2 AGN in the 70 month catalog.

  4. Endoscopic visualization of luminal organ and great vessels with three dimensional CT scanner

    International Nuclear Information System (INIS)

    Kobayashi, Hisashi; Okumura, Toshiyuki; Amemiya, Ryuta; Hasegawa, Hiroshi

    1992-01-01

    Thirty cases examined by three dimensional CT scanner (3DCT) are reported. The observation of inner view using 3DCT were performed in 12 large vessels with vascular disorder, 10 pulmonary bronchi with lung cancer and 8 common bile ducts involved obstructive disease. In order to visualize interface of the lumen, a new software, which was developed by HITACHI MEDICO Inc., was used. In all cases but one the inner view of the luminal organ was clearly demonstrated as 3D images and it was possible to judge some changes of luminal interface involved by the diseases. The 3DCT endoscopic image might be useful as a new endoscopic technique without fiberscopy. (author)

  5. Classification of radioactive self-luminous light sources - approved 1975. NBS Handbook 116

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    The standard establishes the classification of certain radioactive self-luminous light sources according to radionuclide, type of source, activity, and performance requirements. The objectives are to establish minimum prototype testing requirements for radioactive self-luminous light sources, to promote uniformity of marking such sources, and to establish minimum physical performance for such sources. The standard is primarily directed toward assuring adequate containment of the radioactive material. Testing procedures and classification designations are specified for discoloration, temperature, thermal shock, reduced pressure, impact, vibration, and immersion. A range of test requirements is presented according to intended usage and source activity

  6. Light production in the luminous fishes Photoblepharon and Anomalops from the Banda Islands.

    Science.gov (United States)

    Haneda, Y; Tsuji, F I

    1971-07-09

    The unresolved mechanism of light production in Photoblepharon and Anomalops has been reinvestigated in fresh and preserved material. Based on biochemical evidence obtained with emulsions and cell-free extracts of the organs, especially the stimulation of light with reduced flavin mononucleotide, and on electron microscopy of organ sections showing the presence of numerous bacteria, we conclude that the light is produced by symbiotic luminous bacteria. Because of the continuing failure to cultivate the luminous bacteria and because of their morphology, we suggest that the bacteria are of a primitive type called bacteroids.

  7. Synthesis and Properties of Poly(ether sulfone)s with Clustered Sulfonic Groups for PEMFC Applications under Various Relative Humidity.

    Science.gov (United States)

    Lee, Shih-Wei; Chen, Jyh-Chien; Wu, Jin-An; Chen, Kuei-Hsien

    2017-03-22

    Novel sulfonated poly(ether sulfone) copolymers (S4PH-x-PSs) based on a new aromatic diol containing four phenyl substituents at the 2, 2', 6, and 6' positions of 4,4'-diphenyl ether were synthesized. Sulfonation was found to occur exclusively on the 4 position of phenyl substituents by NMR spectroscopy. The ion exchange capacity (IEC) values can be controlled by adjusting the mole percent (x in S4PH-x-PS) of the new diol. The fully hydrated sulfonated poly(ether sulfone) copolymers had good proton conductivity in the range 0.004-0.110 S/cm at room temperature. The surface morphology of S4PH-x-PSs and Nafion 212 was investigated by atomic force microscopy (tapping-mode) and related to the percolation limit and proton conductivity. Single H 2 /O 2 fuel cell based on S4PH-40-PS loaded with 0.25 mg/cm 2 catalyst (Pt/C) exhibited a peak power density of 462.6 mW/cm 2 , which was close to that of Nafion 212 (533.5 mW/cm 2 ) at 80 °C with 80% RH. Furthermore, fuel cell performance of S4PH-35-PS with various relative humidity was investigated. It was confirmed from polarization curves that the fuel cell performance of S4PH-35-PS was not as high as that of Nafion 212 under fully hydrated state due to higher interfacial resistance between S4PH-35-PS and electrodes. While under low relative humidity (53% RH) at 80 °C, fuel cells based on S4PH-35-PS showed higher peak power density (234.9 mW/cm 2 ) than that (214.0 mW/cm 2 ) of Nafion 212.

  8. REVISITING SCALING RELATIONS FOR GIANT RADIO HALOS IN GALAXY CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Cassano, R.; Brunetti, G.; Venturi, T.; Kale, R. [INAF/IRA, via Gobetti 101, I-40129 Bologna (Italy); Ettori, S. [INAF/Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Giacintucci, S. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Pratt, G. W. [Laboratoire AIM, IRFU/Service dAstrophysique-CEA/DSM-CNRS-Université Paris Diderot, Bât. 709, CEA-Saclay, F-91191 Gif-sur-Yvette Cedex (France); Dolag, K. [University Observatory Munich, Scheinerstr. 1, D-81679 Munich (Germany); Markevitch, M. [Astrophysics Science Division, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2013-11-10

    Many galaxy clusters host megaparsec-scale radio halos, generated by ultrarelativistic electrons in the magnetized intracluster medium. Correlations between the synchrotron power of radio halos and the thermal properties of the hosting clusters were established in the last decade, including the connection between the presence of a halo and cluster mergers. The X-ray luminosity and redshift-limited Extended GMRT Radio Halo Survey provides a rich and unique dataset for statistical studies of the halos. We uniformly analyze the radio and X-ray data for the GMRT cluster sample, and use the new Planck Sunyaev-Zel'dovich (SZ) catalog to revisit the correlations between the power of radio halos and the thermal properties of galaxy clusters. We find that the radio power at 1.4 GHz scales with the cluster X-ray (0.1-2.4 keV) luminosity computed within R{sub 500} as P{sub 1.4}∼L{sup 2.1±0.2}{sub 500}. Our bigger and more homogenous sample confirms that the X-ray luminous (L{sub 500} > 5 × 10{sup 44} erg s{sup –1}) clusters branch into two populations—radio halos lie on the correlation, while clusters without radio halos have their radio upper limits well below that correlation. This bimodality remains if we excise cool cores from the X-ray luminosities. We also find that P{sub 1.4} scales with the cluster integrated SZ signal within R{sub 500}, measured by Planck, as P{sub 1.4}∼Y{sup 2.05±0.28}{sub 500}, in line with previous findings. However, contrary to previous studies that were limited by incompleteness and small sample size, we find that 'SZ-luminous' Y{sub 500} > 6 × 10{sup –5} Mpc{sup 2} clusters show a bimodal behavior for the presence of radio halos, similar to that in the radio-X-ray diagram. Bimodality of both correlations can be traced to clusters dynamics, with radio halos found exclusively in merging clusters. These results confirm the key role of mergers for the origin of giant radio halos, suggesting that they trigger the

  9. Suicide Clusters: A Review of Risk Factors and Mechanisms

    Science.gov (United States)

    Haw, Camilla; Hawton, Keith; Niedzwiedz, Claire; Platt, Steve

    2013-01-01

    Suicide clusters, although uncommon, cause great concern in the communities in which they occur. We searched the world literature on suicide clusters and describe the risk factors and proposed psychological mechanisms underlying the spatio-temporal clustering of suicides (point clusters). Potential risk factors include male gender, being an…

  10. TOPOLOGY OF LUMINOUS RED GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

    International Nuclear Information System (INIS)

    Choi, Yun-Young; Kim, Juhan; Rossi, Graziano; Kim, Sungsoo S.; Lee, Jeong-Eun

    2013-01-01

    We present measurements of the genus topology of luminous red galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS) Data Release 7 catalog, with unprecedented statistical significance. To estimate the uncertainties in the measured genus, we construct 81 mock SDSS LRG surveys along the past light cone from Horizon Run 3, one of the largest N-body simulations to date, which evolved 7210 3 particles in a 10,815 h –1  Mpc box. After carefully modeling and removing all known systematic effects due to finite pixel size, survey boundary, radial and angular selection functions, shot noise, and galaxy biasing, we find that the observed genus amplitude reaches 272 at a 22 h –1  Mpc smoothing scale, with an uncertainty of 4.2%; the estimated error fully incorporates cosmic variance. This is the most accurate constraint on the genus amplitude to date and significantly improves on our previous results. In particular, the shape of the genus curve agrees very well with the mean topology of the SDSS LRG mock surveys in a Λ cold dark matter universe. However, comparison with simulations also shows small deviations of the observed genus curve from the theoretical expectation for Gaussian initial conditions. While these discrepancies are mainly driven by known systematic effects such as shot noise and redshift-space distortions, they do contain important cosmological information on the physical effects connected with galaxy formation, gravitational evolution, and primordial non-Gaussianity. We address the key role played by systematics on the genus curve and show how to accurately correct for their effects to recover the topology of the underlying matter. A future work will provide an interpretation of these deviations in the context of the local model of non-Gaussianity

  11. Relativistic radiative transfer in a moving stratus irradiated by a luminous flat source

    Science.gov (United States)

    Fukue, Jun

    2015-06-01

    Relativistic radiative transfer in a geometrically thin stratus (sheet-like gaseous cloud with finite optical depth), which is moving at a relativistic speed around a luminous flat source, such as accretion disks, and is irradiated by the source, is examined under the special relativistic treatment. Incident radiation is aberrated and Doppler-shifted when it is received by the stratus, and emitted radiation is also aberrated and Doppler-shifted when it leaves the stratus. Considering these relativistic effects, we analytically obtain the emergent intensity as well as other radiative quantities in the purely scattering case for both infinite and finite strati. We mainly consider the frequency-integrated case, but also briefly show the frequency-dependent one. We also solve the relativistic radiative transfer equation numerically, and compare the results with the analytical solutions. In the infinite stratus, the mean intensity in the comoving and inertial frames decreases and becomes constant, as the stratus speed increases. The flux in the comoving frame decreases exponentially with the optical depth. The emergent intensity decreases as the speed increases, since the incident photons are redshifted at the bottom-side of the stratus. In the finite stratus, the mean intensity in the comoving and inertial frames quickly increases in the top-side region due to the aberrated photons. The flux in the comoving frame is positive in the range of 0 negative for β ≳ 0.5. The behavior of the emergent intensity is similar to that of the infinite case, although there is an irradiation effect caused by the aberrated photons.

  12. ACOUSTIC SCALE FROM THE ANGULAR POWER SPECTRA OF SDSS-III DR8 PHOTOMETRIC LUMINOUS GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Hee-Jong [Berkeley Center for Cosmological Physics, LBL and Department of Physics, University of California, Berkeley, CA 94720 (United States); Ho, Shirley; White, Martin; Reid, Beth; Schlegel, David J. [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Cuesta, Antonio J.; Padmanabhan, Nikhil [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Ross, Ashley J.; Percival, Will J.; Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth PO1 3FX (United Kingdom); Saito, Shun [Department of Astronomy, 601 Campbell Hall, University of California at Berkeley, Berkeley, CA 94720 (United States); De Putter, Roland [Instituto de Fisica Corpuscular, Valencia (Spain); Eisenstein, Daniel J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS 20, Cambridge, MA 02138 (United States); Xu Xiaoying; Skibba, Ramin [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Schneider, Donald P. [Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802 (United States); Verde, Licia [Institucio Catalana de Recerca i Estudis Avancats, Barcelona (Spain); Bizyaev, Dmitry; Brewington, Howard; Brinkmann, J. [Apache Point Observatory, 2001 Apache Point Road, Sunspot, NM 88349 (United States); and others

    2012-12-10

    We measure the acoustic scale from the angular power spectra of the Sloan Digital Sky Survey III (SDSS-III) Data Release 8 imaging catalog that includes 872, 921 galaxies over {approx}10,000 deg{sup 2} between 0.45 < z < 0.65. The extensive spectroscopic training set of the Baryon Oscillation Spectroscopic Survey luminous galaxies allows precise estimates of the true redshift distributions of galaxies in our imaging catalog. Utilizing the redshift distribution information, we build templates and fit to the power spectra of the data, which are measured in our companion paper, to derive the location of Baryon acoustic oscillations (BAOs) while marginalizing over many free parameters to exclude nearly all of the non-BAO signal. We derive the ratio of the angular diameter distance to the sound horizon scale D{sub A} (z)/r{sub s} = 9.212{sup +0.416}{sub -{sub 0.404}} at z = 0.54, and therefore D{sub A} (z) = 1411 {+-} 65 Mpc at z = 0.54; the result is fairly independent of assumptions on the underlying cosmology. Our measurement of angular diameter distance D{sub A} (z) is 1.4{sigma} higher than what is expected for the concordance {Lambda}CDM, in accordance to the trend of other spectroscopic BAO measurements for z {approx}> 0.35. We report constraints on cosmological parameters from our measurement in combination with the WMAP7 data and the previous spectroscopic BAO measurements of SDSS and WiggleZ. We refer to our companion papers (Ho et al.; de Putter et al.) for investigations on information of the full power spectrum.

  13. A LUMINOUS, FAST RISING UV-TRANSIENT DISCOVERED BY ROTSE: A TIDAL DISRUPTION EVENT?

    International Nuclear Information System (INIS)

    Vinkó, J.; Wheeler, J. C.; Chatzopoulos, E.; Marion, G. H.; Yuan, F.; Akerlof, C.; Quimby, R. M.; Ramirez-Ruiz, E.; Guillochon, J.

    2015-01-01

    We present follow-up observations of an optical transient (OT) discovered by ROTSE on 2009 January 21. Photometric monitoring was carried out with ROTSE-IIIb in the optical and Swift in the UV up to +70 days after discovery. The light curve showed a fast rise time of ∼10 days followed by a steep decline over the next 60 days, which was much faster than that implied by 56 Ni— 56 Co radioactive decay. The Sloan Digital Sky Survey Data Release 10 database contains a faint, red object at the position of the OT, which appears slightly extended. This and other lines of evidence suggest that the OT is of extragalactic origin, and this faint object is likely the host galaxy. A sequence of optical spectra obtained with the 9.2 m Hobby-Eberly Telescope between +8 and +45 days after discovery revealed a hot, blue continuum with no visible spectral features. A few weak features that appeared after +30 days probably originated from the underlying host. Fitting synthetic templates to the observed spectrum of the host galaxy revealed a redshift of z = 0.19. At this redshift, the peak magnitude of the OT is close to –22.5, similar to the brightest super-luminous supernovae; however, the lack of identifiable spectral features makes the massive stellar death hypothesis less likely. A more plausible explanation appears to be the tidal disruption of a Sun-like star by the central supermassive black hole. We argue that this transient likely belongs to a class of super-Eddington tidal disruption events

  14. Symbiosis initiation in the bacterially luminous sea urchin cardinalfish Siphamia versicolor.

    Science.gov (United States)

    Dunlap, P V; Gould, A L; Wittenrich, M L; Nakamura, M

    2012-09-01

    To determine how each new generation of the sea urchin cardinalfish Siphamia versicolor acquires the symbiotic luminous bacterium Photobacterium mandapamensis, and when in its development the S. versicolor initiates the symbiosis, procedures were established for rearing S. versicolor larvae in an aposymbiotic state. Under the conditions provided, larvae survived and developed for 28 days after their release from the mouths of males. Notochord flexion began at 8 days post release (dpr). By 28 dpr, squamation was evident and the caudal complex was complete. The light organ remained free of bacteria but increased in size and complexity during development of the larvae. Thus, aposymbiotic larvae of the fish can survive and develop for extended periods, major components of the luminescence system develop in the absence of the bacteria and the bacteria are not acquired directly from a parent, via the egg or during mouth brooding. Presentation of the symbiotic bacteria to aposymbiotic larvae at 8-10 dpr, but not earlier, led to initiation of the symbiosis. Upon colonization of the light organ, the bacterial population increased rapidly and cells forming the light-organ chambers exhibited a differentiated appearance. Therefore, the light organ apparently first becomes receptive to colonization after 1 week post-release development, the symbiosis is initiated by bacteria acquired from the environment and bacterial colonization induces morphological changes in the nascent light organ. The abilities to culture larvae of S. versicolor for extended periods and to initiate the symbiosis in aposymbiotic larvae are key steps in establishing the experimental tractability of this highly specific vertebrate and microbe mutualism. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  15. Cluster headache

    Directory of Open Access Journals (Sweden)

    Ducros Anne

    2008-07-01

    Full Text Available Abstract Cluster headache (CH is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye. It affects young adults, predominantly males. Prevalence is estimated at 0.5–1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name in bouts that can occur during specific months of the year. Alcohol is the only dietary trigger of CH, strong odors (mainly solvents and cigarette smoke and napping may also trigger CH attacks. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH is associated with trigeminovascular activation and neuroendocrine and vegetative disturbances, however, the precise cautive mechanisms remain unknown. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments and to reduce the number of daily attacks (prophylactic treatments. Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the

  16. The effect of household heads training about the use of treated bed nets on the burden of malaria and anaemia in under-five children: a cluster randomized trial in Ethiopia

    Directory of Open Access Journals (Sweden)

    Deribew Amare

    2012-01-01

    Full Text Available Abstract Background Long-lasting insecticide-treated bed nets (LLITN have demonstrated a significant effect in reducing malaria-related morbidity and mortality. However, barriers on the utilization of LLITN have hampered the desired outcomes. The aim of this study was to assess the effect of community empowerment on the burden of malaria and anaemia in under-five children in Ethiopia. Methods A cluster randomized trial was done in 22 (11 intervention and 11 control villages in south-west Ethiopia. The intervention consisted of tailored training of household heads about the proper use of LLITN and community network system. The burden of malaria and anaemia in under-five children was determined through mass blood investigation at baseline, six and 12 months of the project period. Cases of malaria and anaemia were treated based on the national protocol. The burden of malaria and anaemia between the intervention and control villages was compared using the complex logistic regression model by taking into account the clustering effect. Eight Focus group discussions were conducted to complement the quantitative findings. Results A total of 2,105 household heads received the intervention and the prevalence of malaria and anaemia was assessed among 2410, 2037 and 2612 under-five children at baseline, six and 12 months of the project period respectively. During the high transmission/epidemic season, children in the intervention arm were less likely to have malaria as compared to children in the control arm (OR = 0.42; 95%CI: 0.32, 0.57. Symptomatic malaria also steadily declined in the intervention villages compared to the control villages in the follow up periods. Children in the intervention arm were less likely to be anaemic compared to those in the control arm both at the high (OR = 0.84; 95%CI: 0.71, 0.99 and low (OR = 0.73; 95%CI: 0.60, 0.89 transmission seasons. Conclusion Training of household heads on the utilization of LLITN significantly

  17. Muonic molecular formation under laser irradiation and in the clustered ion molecule (The effect of protonium additive on the muon catalyzed fusion cycle)

    International Nuclear Information System (INIS)

    Takahashi, Hiroshi.

    1988-01-01

    The formation rate of the dtμ molecule is very sensitive to the differences in the vibrational rotational level between D 2 and [(dtμ)-d-2e/] molecules. The density effect of the normalized reaction rate has been studied by the resonance broadening due to collisional quenching. The surrounding molecules of the molecule forming dt/mu/ act as the third body which takes out the excess energy forming dt/mu/ from t/mu/, and the formation reaction occurs with the excitation of the vibrational state just below the threshold energy. By using the laser as the third body, the rate of resonance formation can be increased. In my last paper, the formation rate was calculated under high-intensity laser irradiation, using Vinitsky's model assuming that the laser interacts directly with the deuteron and modulates the interaction between t/mu/ and d/sub 2/ nuclei. However, the laser interacts more strongly with the electrons, because the interaction energy of the laser and the charged particle is proportional to the velocity of the particle's motion, and the velocity of the electron is a few thousand times greater than the velocity of the nuclei. This interaction with electrons was neglected in my last paper. In the present paper, the enhancement of the dt/mu/ formation rates by the strong laser irradiation is studied, taking into account the laser electron interaction; It was shown that the enhancement can be achieved by an intensity lower than the one described previously. 29 refs., 5 figs., 3 tabs

  18. Cosmological constraints from Chandra observations of galaxy clusters.

    Science.gov (United States)

    Allen, Steven W

    2002-09-15

    Chandra observations of rich, relaxed galaxy clusters allow the properties of the X-ray gas and the total gravitating mass to be determined precisely. Here, we present results for a sample of the most X-ray luminous, dynamically relaxed clusters known. We show that the Chandra data and independent gravitational lensing studies provide consistent answers on the mass distributions in the clusters. The mass profiles exhibit a form in good agreement with the predictions from numerical simulations. Combining Chandra results on the X-ray gas mass fractions in the clusters with independent measurements of the Hubble constant and the mean baryonic matter density in the Universe, we obtain a tight constraint on the mean total matter density of the Universe, Omega(m), and an interesting constraint on the cosmological constant, Omega(Lambda). We also describe the 'virial relations' linking the masses, X-ray temperatures and luminosities of galaxy clusters. These relations provide a key step in linking the observed number density and spatial distribution of clusters to the predictions from cosmological models. The Chandra data confirm the presence of a systematic offset of ca. 40% between the normalization of the observed mass-temperature relation and the predictions from standard simulations. This finding leads to a significant revision of the best-fit value of sigma(8) inferred from the observed temperature and luminosity functions of clusters.

  19. Distinct choline metabolic profiles are associated with differences in gene expression for basal-like and luminal-like breast cancer xenograft models

    International Nuclear Information System (INIS)

    Moestue, Siver A; Borgan, Eldrid; Huuse, Else M; Lindholm, Evita M; Sitter, Beathe; Børresen-Dale, Anne-Lise; Engebraaten, Olav; Mælandsmo, Gunhild M; Gribbestad, Ingrid S

    2010-01-01

    Increased concentrations of choline-containing compounds are frequently observed in breast carcinomas, and may serve as biomarkers for both diagnostic and treatment monitoring purposes. However, underlying mechanisms for the abnormal choline metabolism are poorly understood. The concentrations of choline-derived metabolites were determined in xenografted primary human breast carcinomas, representing basal-like and luminal-like subtypes. Quantification of metabolites in fresh frozen tissue was performed using high-resolution magic angle spinning magnetic resonance spectroscopy (HR MAS MRS). The expression of genes involved in phosphatidylcholine (PtdCho) metabolism was retrieved from whole genome expression microarray analyses. The metabolite profiles from xenografts were compared with profiles from human breast cancer, sampled from patients with estrogen/progesterone receptor positive (ER+/PgR+) or triple negative (ER-/PgR-/HER2-) breast cancer. In basal-like xenografts, glycerophosphocholine (GPC) concentrations were higher than phosphocholine (PCho) concentrations, whereas this pattern was reversed in luminal-like xenografts. These differences may be explained by lower choline kinase (CHKA, CHKB) expression as well as higher PtdCho degradation mediated by higher expression of phospholipase A2 group 4A (PLA2G4A) and phospholipase B1 (PLB1) in the basal-like model. The glycine concentration was higher in the basal-like model. Although glycine could be derived from energy metabolism pathways, the gene expression data suggested a metabolic shift from PtdCho synthesis to glycine formation in basal-like xenografts. In agreement with results from the xenograft models, tissue samples from triple negative breast carcinomas had higher GPC/PCho ratio than samples from ER+/PgR+ carcinomas, suggesting that the choline metabolism in the experimental models is representative for luminal-like and basal-like human breast cancer. The differences in choline metabolite

  20. Preparation of Agcore/Aushell bimetallic nanoparticles from physical mixtures of Au clusters and Ag ions under dark conditions and their catalytic activity for aerobic glucose oxidation

    International Nuclear Information System (INIS)

    Zhang, Haijun; Toshima, Naoki; Takasaki, Kanako; Okumura, Mitsutaka

    2014-01-01

    Graphical abstract: The synthesis, characterization and catalytic activities for glucose oxidation of AgAu bimetallic nanoparticles (BNPs) with size of less than 2 nm are reported. The catalytic activity of Ag 10 Au 90 BNPs was about two times higher than that of Au NPs, even the BNPs have a larger particle size than that of Au NPs. -- Highlights: • Ag core /Au shell BNPs with size of less than 2.0 nm were prepared. • No any reducing reagents and lights were used for the preparation of the BNPs. • The catalytic activity of the BNPs is about two times higher than that of Au NPs. -- Abstract: AgAu bimetallic nanoparticles (BNPs), one of the most extensively studied bimetallic systems in the literatures, could have various structures and compositions depending on their preparation conditions. In the present work, catalytically highly active PVP-protected Ag core /Au shell BNPs of about 2.5 nm in diameter were fabricated from physical mixtures of aqueous dispersions of Au nanoparticles and Ag + ions under dark conditions without using any reducing agents. The prepared Ag core /Au shell BNP colloidal catalysts, which possessed a high activity for aerobic glucose oxidation, were characterized by Ultraviolet–visible spectrophotometry (UV–Vis), Inductive coupled plasma emission spectrometer (ICP), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Energy disperse spectroscopy (EDS) in High-resolution scanning transmission electron microscopy (HR-STEM). The highest activity (11,360 mol-glucose h −1 mol-metal −1 ) was observed for the BNPs with the Ag/Au atomic ratio of 1/9, the TOF value of which is about two times higher than that of Au nanoparticles with the particle size of 1.3 nm. The enhanced catalytic activity of the prepared Ag core /Au shell BNPs compared to Au NPs can be ascribed to the presence of negatively charged Au atoms resulted from electron donations from neighboring Ag atoms and PVP due to electronic charge

  1. Impact of pharmacy worker training and deployment on access to essential medicines for children under five in Malawi: a cluster quasi-experimental evaluation.

    Science.gov (United States)

    Babigumira, Joseph B; Lubinga, Solomon J; Jenny, Alisa M; Larsen-Cooper, Erin; Crawford, Jessica; Matemba, Charles; Stergachis, Andy

    2017-09-11

    Poor access to essential medicines is common in many low- and middle-income countries, partly due to an insufficient and inadequately trained workforce to manage the medicines supply chain. We conducted a prospective impact evaluation of the training and deployment of pharmacy assistants (PAs) to rural health centers in Malawi. A quasi-experimental design was used to compare access to medicines in two districts where newly trained PAs were deployed to health centers (intervention) and two districts with no trained PAs at health centers (comparison). A baseline household survey and two annual post-intervention household surveys were conducted. We studied children under five years with a history of fever, cough and difficulty in breathing, and diarrhea in the previous two weeks. We collected data on access to antimalarials, antibiotics and oral rehydration salts (ORS) during the childrens' symptomatic periods. We used difference-in-differences regression models to estimate the impact of PA training and deployment on access to medicines. We included 3974 children across the three rounds of annual surveys: 1840 (46%) in the districts with PAs deployed at health centers and 2096 (53%) in districts with no PAs deployed at health centers. Approximately 80% of children had a fever, nearly 30% had a cough, and 43% had diarrhea in the previous two weeks. In the first year of the program, the presence of a PA led to a significant 74% increase in the odds of access to any antimalarial, and a significant 49% increase in the odds of access to artemisinin combination therapies. This effect was restricted to the first year post-intervention. There was no effect of presence of a PA on access to antibiotics or ORS. The training and deployment of pharmacy assistants to rural health centers in Malawi increased access to antimalarial medications over the first year, but the effect was attenuated over the second year. Pharmacy assistants training and deployment demonstrated no impact on

  2. Changing cluster composition in cluster randomised controlled trials: design and analysis considerations

    Science.gov (United States)

    2014-01-01

    Background There are many methodological challenges in the conduct and analysis of cluster randomised controlled trials, but one that has received little attention is that of post-randomisation changes to cluster composition. To illustrate this, we focus on the issue of cluster merging, considering the impact on the design, analysis and interpretation of trial outcomes. Methods We explored the effects of merging clusters on study power using standard methods of power calculation. We assessed the potential impacts on study findings of both homogeneous cluster merges (involving clusters randomised to the same arm of a trial) and heterogeneous merges (involving clusters randomised to different arms of a trial) by simulation. To determine the impact on bias and precision of treatment effect estimates, we applied standard methods of analysis to different populations under analysis. Results Cluster merging produced a systematic reduction in study power. This effect depended on the number of merges and was most pronounced when variability in cluster size was at its greatest. Simulations demonstrate that the impact on analysis was minimal when cluster merges were homogeneous, with impact on study power being balanced by a change in observed intracluster correlation coefficient (ICC). We found a decrease in study power when cluster merges were heterogeneous, and the estimate of treatment effect was attenuated. Conclusions Examples of cluster merges found in previously published reports of cluster randomised trials were typically homogeneous rather than heterogeneous. Simulations demonstrated that trial findings in such cases would be unbiased. However, simulations also showed that any heterogeneous cluster merges would introduce bias that would be hard to quantify, as well as having negative impacts on the precision of estimates obtained. Further methodological development is warranted to better determine how to analyse such trials appropriately. Interim recommendations

  3. 10 CFR 32.101 - Schedule B-prototype tests for luminous safety devices for use in aircraft.

    Science.gov (United States)

    2010-01-01

    ....101 Schedule B—prototype tests for luminous safety devices for use in aircraft. An applicant for a... 10 Energy 1 2010-01-01 2010-01-01 false Schedule B-prototype tests for luminous safety devices for use in aircraft. 32.101 Section 32.101 Energy NUCLEAR REGULATORY COMMISSION SPECIFIC DOMESTIC LICENSES...

  4. 10 CFR 32.22 - Self-luminous products containing tritium, krypton-85 or promethium-147: Requirements for license...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Self-luminous products containing tritium, krypton-85 or... containing tritium, krypton-85 or promethium-147: Requirements for license to manufacture, process, produce... self-luminous products containing tritium, krypton-85, or promethium-147, or to initially transfer such...

  5. The ER stress sensor PERK luminal domain functions as a molecular chaperone to interact with misfolded proteins

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng; Li, Jingzhi; Sha, Bingdong

    2016-11-29

    PERK is one of the major sensor proteins which can detect the protein-folding imbalance generated by endoplasmic reticulum (ER) stress. It remains unclear how the sensor protein PERK is activated by ER stress. It has been demonstrated that the PERK luminal domain can recognize and selectively interact with misfolded proteins but not native proteins. Moreover, the PERK luminal domain may function as a molecular chaperone to directly bind to and suppress the aggregation of a number of misfolded model proteins. The data strongly support the hypothesis that the PERK luminal domain can interact directly with misfolded proteins to induce ER stress signaling. To illustrate the mechanism by which the PERK luminal domain interacts with misfolded proteins, the crystal structure of the human PERK luminal domain was determined to 3.2 Å resolution. Two dimers of the PERK luminal domain constitute a tetramer in the asymmetric unit. Superimposition of the PERK luminal domain molecules indicated that the β-sandwich domain could adopt multiple conformations. It is hypothesized that the PERK luminal domain may utilize its flexible β-sandwich domain to recognize and interact with a broad range of misfolded proteins.

  6. Partitional clustering algorithms

    CERN Document Server

    2015-01-01

    This book summarizes the state-of-the-art in partitional clustering. Clustering, the unsupervised classification of patterns into groups, is one of the most important tasks in exploratory data analysis. Primary goals of clustering include gaining insight into, classifying, and compressing data. Clustering has a long and rich history that spans a variety of scientific disciplines including anthropology, biology, medicine, psychology, statistics, mathematics, engineering, and computer science. As a result, numerous clustering algorithms have been proposed since the early 1950s. Among these algorithms, partitional (nonhierarchical) ones have found many applications, especially in engineering and computer science. This book provides coverage of consensus clustering, constrained clustering, large scale and/or high dimensional clustering, cluster validity, cluster visualization, and applications of clustering. Examines clustering as it applies to large and/or high-dimensional data sets commonly encountered in reali...

  7. Dynamic contrast-enhanced MRI in patients with luminal Crohn's disease

    NARCIS (Netherlands)

    Ziech, M. L. W.; Lavini, C.; Caan, M. W. A.; Nio, C. Y.; Stokkers, P. C. F.; Bipat, S.; Ponsioen, C. Y.; Nederveen, A. J.; Stoker, J.

    2012-01-01

    Objectives: To prospectively assess dynamic contrast-enhanced (DCE-)MRI as compared to conventional sequences in patients with luminal Crohn's disease. Methods: Patients with Crohn's disease undergoing MRI and ileocolonoscopy within 1 month had DCE-MRI (3T) during intravenous contrast injection of

  8. First observations of transient luminous events in Indian sub-continent

    DEFF Research Database (Denmark)

    Singh, Rajesh; Maurya, Ajeet K.; Veenadhari, B.

    2014-01-01

    The article offers information on the initial observations of flashes of lightning discharge observed above thunderstorms. It mentions that the transient luminous events (TLE) are classified on the basis of their geometrical shape and luminosity into Sprites, Halos and Blue Starters. It also focu...

  9. A Semi-Automatic, Remote-Controlled Video Observation System for Transient Luminous Events

    DEFF Research Database (Denmark)

    Allin, Thomas Højgaard; Neubert, Torsten; Laursen, Steen

    2003-01-01

    In support for global ELF/VLF observations, HF measurements in France, and conjugate photometry/VLF observations in South Africa, we developed and operated a semi-automatic, remotely controlled video system for the observation of middle-atmospheric transient luminous events (TLEs). Installed...

  10. The galactic luminous supersoft X-ray source RXJ0925.7-4758 / MR ...

    Indian Academy of Sciences (India)

    Nandita Prodhani

    2018-01-30

    Jan 30, 2018 ... White dwarf; luminous supersoft X-ray source; luminosity; absorption edge. PACS Nos 97.80.Jp; 97.10.Ri; 98.35.Mp; 97.80.Fk. 1. Introduction. For the last few decades, Einstein observatory, Roent- gen Satellite (ROSAT), ASCA, CHANDRA, XMM-. Newton, SWIFT, SUZAKU and other ingenious devices.

  11. 78 FR 29391 - Luminant Generation Company, LLC; Combined License Application for Comanche Peak Nuclear Power...

    Science.gov (United States)

    2013-05-20

    ... only temporary relief from the applicable regulation and the licensee has made good faith efforts to... only temporary relief from the regulations of 10 CFR 50.71(e)(3)(iii). Luminant has made good faith... applicable regulation and the licensee has made good faith efforts to comply with the regulation'' (10 CFR 50...

  12. Maturation of polarization and luminance contrast sensitivities in cuttlefish (Sepia officinalis).

    Science.gov (United States)

    Cartron, Lelia; Dickel, Ludovic; Shashar, Nadav; Darmaillacq, Anne-Sophie

    2013-06-01

    Polarization sensitivity is a characteristic of the visual system of cephalopods. It has been well documented in adult cuttlefish, which use polarization sensitivity in a large range of tasks such as communication, orientation and predation. Because cuttlefish do not benefit from parental care, their visual system (including the ability to detect motion) must be efficient from hatching to enable them to detect prey or predators. We studied the maturation and functionality of polarization sensitivity in newly hatched cuttlefish. In a first experiment, we examined the response of juvenile cuttlefish from hatching to the age of 1 month towards a moving, vertically oriented grating (contrasting and polarized stripes) using an optomotor response apparatus. Cuttlefish showed differences in maturation of polarization versus luminance contrast motion detection. In a second experiment, we examined the involvement of polarization information in prey preference and detection in cuttlefish of the same age. Cuttlefish preferentially chose not to attack transparent prey whose polarization contrast had been removed with a depolarizing filter. Performances of prey detection based on luminance contrast improved with age. Polarization contrast can help cuttlefish detect transparent prey. Our results suggest that polarization is not a simple modulation of luminance information, but rather that it is processed as a distinct channel of visual information. Both luminance and polarization sensitivity are functional, though not fully matured, in newly hatched cuttlefish and seem to help in prey detection.

  13. Informational primacy of visual dimensions: specialized roles for luminance and chromaticity in figure-ground perception.

    Science.gov (United States)

    Yamagishi, N; Melara, R D

    2001-07-01

    Three experiments were conducted to examine the distinct contributions of two visual dimensions to figure-ground segregation. In each experiment, pattern identification was assessed by asking observers to judge whether a near-threshold test pattern was the same or different in shape to a high-contrast comparison pattern. A test pattern could differ from its background along one dimension, either luminance (luminance tasks) or chromaticity (chromaticity tasks). In each task, performance in a baseline condition, in which the test pattern was intact, was compared with performance in each of several degradation conditions, in which either the contour or the surface of the figure was degraded, using either partial occlusion (Experiment 1) or ramping (Experiments 2 and 3) of figure-ground differences. In each experiment, performance in luminance tasks was worst when the contour was degraded, whereas performance in chromaticity tasks was worst when the surface was degraded. This interaction was found even when spatial frequencies were fixed across test patterns by low-pass filtering. The results are consistent with a late (postfiltering) dual-mechanism system that processes luminance information to extract boundary representations and chromaticity information to extract surface representations.

  14. Visual memory for random block patterns defined by luminance and color contrast

    NARCIS (Netherlands)

    Cornelissen, FW; Greenlee, MW

    2000-01-01

    We studied the ability of human subjects to memorize the visual information in computer-generated random block patterns defined either by luminance contrast, by color contrast, or by both. Memory performance declines rapidly with increasing inter-stimulus interval, showing a half-life of

  15. Defining optimal duration and predicting benefit from chemotherapy in patients with luminal-like subtypes.

    Science.gov (United States)

    Hart, Christopher D; Sanna, Giuseppina; Siclari, Olimpia; Biganzoli, Laura; Di Leo, Angelo

    2015-11-01

    The molecular subtypes of breast cancer have individual patterns of behaviour, prognosis and sensitivity to treatment, with subsequent implications for the choice of, or indeed role for adjuvant therapy. The luminal A and B subtypes make up the majority of breast cancers, but despite sharing expression of the oestrogen receptor (ER), they are molecularly distinct. It follows then that they would have different sensitivities to chemotherapy. Clinically, luminal A disease has a better prognosis than luminal B, and may not derive significant benefit from adjuvant chemotherapy. However no prospective trials have specifically investigated the benefit of adjuvant chemotherapy in each subtype, nor do we know if certain agents are more or less effective. This paper will briefly summarise the role of molecular profiles in assessing the need for chemotherapy and predicting its effectiveness, followed by an assessment of the relative value of newer anthracycline- or taxane-containing regimes in the luminal-like subtypes, providing a review of retrospective analyses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. UVB-activated psoralen reduces luminal narrowing after balloon dilation because of inhibition of constrictive remodeling

    NARCIS (Netherlands)

    Perrée, Jop; van Leeuwen, Ton G.; Velema, Evelyn; Smeets, Mirjam; de Kleijn, Dominique; Borst, Cornelius

    2002-01-01

    In this study we have explored the potential of PUVB (8-MOP + UVB) therapy for the reduction of luminal narrowing after arterial injury. In 15 rabbits, balloon dilation of iliac arteries was performed. In 20 arteries, dilation was combined with the delivery of pulsed ultraviolet light B (UVB)

  17. Cloning and characterization of luciferase from a Fijian luminous click beetle.

    Science.gov (United States)

    Mitani, Yasuo; Futahashi, Ryo; Niwa, Kazuki; Ohba, Nobuyoshi; Ohmiya, Yoshihiro

    2013-01-01

    Luminous click beetle is distributed almost exclusively in Central and South America with a single genus in Melanesia. Among these click beetles, the description of Melanesian species has been fragmentary, and its luciferase gene and phylogenetic relation to other click beetles still remain uncertain. We collected a living luminous click beetle, Photophorus jansonii in Fiji. It emits green-yellow light from two spots on the pronotum and has no ventral luminous organ. Here, we cloned a luciferase gene from this insect by RT-PCR. The deduced amino acid sequence showed high identity of ~85% to the luciferases derived from other click beetle species. The luciferase of the Fijian click beetle was produced as a recombinant protein to characterize its biochemical properties. The Km for D-luciferin and ATP were 173 and 270 μm, respectively. The luciferase was pH-insensitive and the spectrum measured at pH 8.0 showed a peak at 559 nm, which was in the range of green-yellow light as seen in the luminous spot of the living Fijian click beetle. The Fijian click beetle luciferase was assigned to the Elateridae clade by a phylogenetic analysis, but it made a clearly different branch from Pyrophorus group examined in this study. © 2013 The American Society of Photobiology.

  18. Modeling blue stragglers in young clusters

    International Nuclear Information System (INIS)

    Lu Pin; Deng Licai; Zhang Xiaobin

    2011-01-01

    A grid of binary evolution models are calculated for the study of a blue straggler (BS) population in intermediate age (log Age = 7.85–8.95) star clusters. The BS formation via mass transfer and merging is studied systematically using our models. Both Case A and B close binary evolutionary tracks are calculated for a large range of parameters. The results show that BSs formed via Case B are generally bluer and even more luminous than those produced by Case A. Furthermore, the larger range in orbital separations of Case B models provides a probability of producing more BSs than in Case A. Based on the grid of models, several Monte-Carlo simulations of BS populations in the clusters in the age range are carried out. The results show that BSs formed via different channels populate different areas in the color magnitude diagram (CMD). The locations of BSs in CMD for a number of clusters are compared to our simulations as well. In order to investigate the influence of mass transfer efficiency in the models and simulations, a set of models is also calculated by implementing a constant mass transfer efficiency, β = 0.5, during Roche lobe overflow (Case A binary evolution excluded). The result shows BSs can be formed via mass transfer at any given age in both cases. However, the distributions of the BS populations on CMD are different.

  19. What causes IOR? Attention or perception? - manipulating cue and target luminance in either blocked or mixed condition.

    Science.gov (United States)

    Zhao, Yuanyuan; Heinke, Dietmar

    2014-12-01

    Inhibition of return (IOR) refers to the performance disadvantage when detecting a target presented at a previously cued location. The current paper contributes to the long-standing debate whether IOR is caused by attentional processing or perceptual processing. We present a series of four experiments which varied the cue luminance in mixed and blocked conditions. We hypothesised that if inhibition was initialized by an attentional process the size of IOR should not vary in the blocked condition as participants should be able to adapt to the level of cue luminance. However, if a perceptual process triggers inhibition both experimental manipulations should lead to varying levels of IOR. Indeed, we found evidence for the latter hypothesis. In addition, we also varied the target luminance in blocked and mixed condition. Both manipulations, cue luminance and target luminance, affected IOR in an additive fashion suggesting that the two stimuli affect human behaviour on different processing stages. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Gas phase reactivity of thermal metal clusters

    International Nuclear Information System (INIS)

    Castleman, A.W. Jr.; Harms, A.C.; Leuchtner, R.E.

    1991-01-01

    Reaction kinetics of metal cluster ions under well defined thermal conditions were studied using a flow tube reactor in combination with laser vaporization. Aluminum anions and cations were reacted with oxygen, and several species which are predicted jellium shell closings, were found to have special stability. Metal alloy cluster anions comprised of Al, V and Nb were also seen to react with oxygen. Alloy clusters with an even number of electrons reacted more slowly than odd electron species, and certain clusters appeared to be exceptionally unreactive. Copper cation clusters were observed to associate with carbon monoxide with reactivities that approach bulk behavior at surprisingly small cluster size. These reactions demonstrate how the rate of reaction changes with cluster size. (orig.)

  1. Gas phase reactivity of thermal metal clusters

    Science.gov (United States)

    Castleman, A. W., Jr.; Harms, A. C.; Leuchtner, R. E.

    1991-03-01

    Reaction kinetics of metal cluster ions under well defined thermal conditions were studied using a flow tube reactor in combination with laser vaporization. Aluminum anions and cations were reacted with oxygen, and several species which are predicted jellium shell closings, were found to have special stability. Metal alloy cluster anions comprised of Al, V and Nb were also seen to react with oxygen. Alloy clusters with an even number of electrons reacted more slowly than odd electron species, and certain clusters appeared to be exceptionally unreactive. Copper cation clusters were observed to associate with carbon monoxide with reactivities that approach bulk behavior at surprisingly small cluster size. These reactions demonstrate how the rate of reaction changes with cluster size.

  2. Photometric studies of globular clusters in the Andromeda Nebula. Luminosity function for old globular clusters

    International Nuclear Information System (INIS)

    Sharov, A.S.; Lyutyj, V.M.

    1989-01-01

    The luminosity function for old globular clusters in M 31 is presented. The objects were selected according to their structural and photometric properties. At the usually accepted normal (Gaussian) distribution, the luminosity function is characterized by the following parameters: the mean magnitude, corrected for the extinction inside M 31, V-bar 0 =16 m ,38±0 m .08, and the absolute magnitude M-bar v =-8 m .29 assuming )m-M) v =23 m .67, standard deviation σ M v =1 m .16±0 m .08 and total object number N=300±17. Old globular clusters in M 31 are in the average about one magnitude more luminous then those in our Galaxy (M v ≅ -7 m .3). Intrinsic luminosity dispersions of globular clusters are nearly the same in both galaxies. Available data on globular clusters in the Local Group galaxies against the universality of globular luminosity function with identical parameters M v and σ M v

  3. Effects of feeding on luminal pH and morphology of the gastroesophageal junction of snakes.

    Science.gov (United States)

    Bessler, Scott M; Secor, Stephen M

    2012-10-01

    At the gastroesophageal junction, most vertebrates possess a functional lower esophageal sphincter (LES) which may serve to regulate the passage of liquids and food into the stomach and prevent the reflux of gastric contents into the esophagus. Snakes seemingly lack an LES and consume meals large enough to extend anteriorly from the stomach into the esophagus thereby providing the opportunity for the reflux of gastric juices. To explore whether snakes experience or can prevent gastric reflux, we examined post-feeding changes of luminal pH of the distal esophagus and stomach, the fine scale luminal pH profile at the gastroesophageal junction, and the morphology of the gastroesophageal junction for the Burmese python (Python molurus), the African brown house snake (Lamprophis fuliginosus), and the diamondback water snake (Nerodia rhombifer). For each species fasted, there was no distension of the gastroesophageal junction and only modest changes in luminal pH from the distal esophagus into the stomach. Feeding resulted in marked distension and changes in tissue morphology of the gastroesophageal junction. Simultaneously, there was a significant decrease in luminal pH of the distal esophagus for pythons and house snakes, and for all three species a steep gradient in luminal pH decreasing across a 3-cm span from the distal edge of the esophagus into the proximal edge of the stomach. The moderate acidification of the distal most portion of the esophagus for pythons and house snakes suggests that there is some anterior movement of gastric juices across the gastroesophageal junction. Given that this modest reflux of gastric fluid is localized to the most distal region of the esophagus, snakes are apparently able to prevent and protect against acid reflux in the absence of a functional LES. Copyright © 2012 Elsevier GmbH. All rights reserved.

  4. Low luminance/eyes closed and monochromatic stimulations reduce variability of flash visual evoked potential latency

    Directory of Open Access Journals (Sweden)

    Senthil Kumar Subramanian

    2013-01-01

    Full Text Available Context: Visual evoked potentials are useful in investigating the physiology and pathophysiology of the human visual system. Flash visual evoked potential (FVEP, though technically easier, has less clinical utility because it shows great variations in both latency and amplitude for normal subjects. Aim: To study the effect of eye closure, low luminance, and monochromatic stimulation on the variability of FVEPs. Subjects and Methods: Subjects in self-reported good health in the age group of 18-30 years were divided into three groups. All participants underwent FVEP recording with eyes open and with white light at 0.6 J luminance (standard technique. Next recording was done in group 1 with closed eyes, group 2 with 1.2 and 20 J luminance, and group 3 with red and blue lights, while keeping all the other parameters constant. Two trials were given for each eye, for each technique. The same procedure was repeated at the same clock time on the following day. Statistical Analysis: Variation in FVEP latencies between the individuals (interindividual variability and the variations within the same individual for four trials (intraindividual variability were assessed using coefficient of variance (COV. The technique with lower COV was considered the better method. Results: Recording done with closed eyes, 0.6 J luminance, and monochromatic light (blue > red showed lower interindividual and intraindividual variability in P2 and N2 as compared to standard techniques. Conclusions: Low luminance flash stimulations and monochromatic light will reduce FVEP latency variability and may be clinically useful modifications of FVEP recording technique.

  5. A multiwavelength and multiscale study of Luminous and Ultraluminous Infrared Galaxies in the local Universe

    Science.gov (United States)

    Herrero-Illana, Rubén

    2014-10-01

    This dissertation deals with the multiwavelength study of luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs, respectively) in the local Universe under different spatial scales. The work is focused on the properties of massive starbursts, the contribution of active galactic nuclei (AGN) and the interplay between both phenomena. The study of local (U)LIRGs is the best scenario where to understand the properties of these objects at cosmological distances, where their luminosity contribution dominates the cosmic infrared background. Our first approach to the study of (U)LIRGs consisted of a spectral line study in the millimeter range, obtained with the IRAM 30m radio-telescope in Pico Veleta, Granada of a subsample of 56 (U)LIRGs from the GOALS project sample. We observed and analyzed spectra of several molecular features, focusing in the study of carbon monoxide (CO), a well-known tracer of cold molecular gas. We explored the relation between them as well as the properties of molecular gas. Besides of the sample characterization, we confirmed the increase of the isotopic ratio 12CO/13CO with the dust temperature, explained by the 12CO optical depth decreasing with temperature. We have also studied the kinematics and gas distribution using the spectral profiles of several molecular transitions. In a second part of this thesis, we analyzed the central kiloparsec region of a sample of 12 LIRGs, stressing the importance of the multiwavelength approach, aimed at deriving the star formation processes of these galaxies, as well as to study the contribution of the putative AGN to the bolometric luminosity in our sample. For one of these LIRGs, NGC1614, we performed a deep multiwavelength study, including data from radio, infrared, optical and X-rays. These data allowed us to establish that the the IR emission in the circumnuclear region is completely dominated by a powerful starburst and, in case it hosts an AGN, its contribution is irrelevant. We also performed

  6. Diversity among galaxy clusters

    International Nuclear Information System (INIS)

    Struble, M.F.; Rood, H.J.

    1988-01-01

    The classification of galaxy clusters is discussed. Consideration is given to the classification scheme of Abell (1950's), Zwicky (1950's), Morgan, Matthews, and Schmidt (1964), and Morgan-Bautz (1970). Galaxies can be classified based on morphology, chemical composition, spatial distribution, and motion. The correlation between a galaxy's environment and morphology is examined. The classification scheme of Rood-Sastry (1971), which is based on clusters's morphology and galaxy population, is described. The six types of clusters they define include: (1) a cD-cluster dominated by a single large galaxy, (2) a cluster dominated by a binary, (3) a core-halo cluster, (4) a cluster dominated by several bright galaxies, (5) a cluster appearing flattened, and (6) an irregularly shaped cluster. Attention is also given to the evolution of cluster structures, which is related to initial density and cluster motion

  7. Properties of an ionised-cluster beam from a vaporised-cluster ion source

    International Nuclear Information System (INIS)

    Takagi, T.; Yamada, I.; Sasaki, A.

    1978-01-01

    A new type of ion source vaporised-metal cluster ion source, has been developed for deposition and epitaxy. A cluster consisting of 10 2 to 10 3 atoms coupled loosely together is formed by adiabatic expansion ejecting the vapour of materials into a high-vacuum region through the nozzle of a heated crucible. The clusters are ionised by electron bombardment and accelerated with neutral clusters toward a substrate. In this paper, mechanisms of cluster formation experimental results of the cluster size (atoms/cluster) and its distribution, and characteristics of the cluster ion beams are reported. The size is calculated from the kinetic equation E = (1/2)mNVsub(ej) 2 , where E is the cluster beam energy, Vsub(ej) is the ejection velocity, m is the mass of atom and N is the cluster size. The energy and the velocity of the cluster are measured by an electrostatic 127 0 energy analyser and a rotating disc system, respectively. The cluster size obtained for Ag is about 5 x 10 2 to 2 x 10 3 atoms. The retarding potential method is used to confirm the results for Ag. The same dependence on cluster size for metals such as Ag, Cu and Pb has been obtained in previous experiments. In the cluster state the cluster ion beam is easily produced by electron bombardment. About 50% of ionised clusters are obtained under typical operation conditions, because of the large ionisation cross sections of the clusters. To obtain a uniform spatial distribution, the ionising electrode system is also discussed. The new techniques are termed ionised-cluster beam deposition (ICBD) and epitaxy (ICBE). (author)

  8. The next generation Virgo cluster survey. VIII. The spatial distribution of globular clusters in the Virgo cluster

    Energy Technology Data Exchange (ETDEWEB)

    Durrell, Patrick R.; Accetta, Katharine [Department of Physics and Astronomy, Youngstown State University, Youngstown, OH 44555 (United States); Côté, Patrick; Blakeslee, John P.; Ferrarese, Laura; McConnachie, Alan; Gwyn, Stephen [Herzberg Astronomy and Astrophysics, National Research Council, 5071 West Saanich Road, Victoria, BC V9E 2E7 (Canada); Peng, Eric W.; Zhang, Hongxin [Department of Astronomy, Peking University, Beijing 100871 (China); Mihos, J. Christopher [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Puzia, Thomas H.; Jordán, Andrés [Institute of Astrophysics, Pontificia Universidad Catolica, Av. Vicu' a Mackenna 4860, Macul 7820436, Santiago (Chile); Lançon, Ariane [Observatoire astronomique de Strasbourg, Université de Strasbourg, CNRS, UMR 7550, 11 rue de l' Université, F-67000 Strasbourg (France); Liu, Chengze [Center for Astronomy and Astrophysics, Department of Physics and Astronomy, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Cuillandre, Jean-Charles [Canada-France-Hawaii Telescope Corporation, Kamuela, HI 96743 (United States); Boissier, Samuel; Boselli, Alessandro [Aix Marseille Université, CNRS, LAM (Laboratoire d' Astrophysique de Marseille) UMR 7326, F-13388 Marseille (France); Courteau, Stéphane [Department of Physics, Engineering Physics and Astronomy, Queen' s University, Kingston, ON K7L 3N6 (Canada); Duc, Pierre-Alain [AIM Paris Saclay, CNRS/INSU, CEA/Irfu, Université Paris Diderot, Orme des Merisiers, F-91191 Gif sur Yvette cedex (France); Emsellem, Eric [Université de Lyon 1, CRAL, Observatoire de Lyon, 9 av. Charles André, F-69230 Saint-Genis Laval (France); CNRS, UMR 5574, ENS de Lyon (France); and others

    2014-10-20

    We report on a large-scale study of the distribution of globular clusters (GCs) throughout the Virgo cluster, based on photometry from the Next Generation Virgo Cluster Survey (NGVS), a large imaging survey covering Virgo's primary subclusters (Virgo A = M87 and Virgo B = M49) out to their virial radii. Using the g{sub o}{sup ′}, (g' – i') {sub o} color-magnitude diagram of unresolved and marginally resolved sources within the NGVS, we have constructed two-dimensional maps of the (irregular) GC distribution over 100 deg{sup 2} to a depth of g{sub o}{sup ′} = 24. We present the clearest evidence to date showing the difference in concentration between red and blue GCs over the full extent of the cluster, where the red (more metal-rich) GCs are largely located around the massive early-type galaxies in Virgo, while the blue (metal-poor) GCs have a much more extended spatial distribution with significant populations still present beyond 83' (∼215 kpc) along the major axes of both M49 and M87. A comparison of our GC maps to the diffuse light in the outermost regions of M49 and M87 show remarkable agreement in the shape, ellipticity, and boxiness of both luminous systems. We also find evidence for spatial enhancements of GCs surrounding M87 that may be indicative of recent interactions or an ongoing merger history. We compare the GC map to that of the locations of Virgo galaxies and the X-ray intracluster gas, and find generally good agreement between these various baryonic structures. We calculate the Virgo cluster contains a total population of N {sub GC} = 67, 300 ± 14, 400, of which 35% are located in M87 and M49 alone. For the first time, we compute a cluster-wide specific frequency S {sub N,} {sub CL} = 2.8 ± 0.7, after correcting for Virgo's diffuse light. We also find a GC-to-baryonic mass fraction ε {sub b} = 5.7 ± 1.1 × 10{sup –4} and a GC-to-total cluster mass formation efficiency ε {sub t} = 2.9 ± 0.5 × 10{sup –5

  9. High-protein diet modifies colonic microbiota and luminal environment but not colonocyte metabolism in the rat model: the increased luminal bulk connection

    OpenAIRE

    LIU, Xinxin; BLOUIN, Jean-Marc; Santacruz, Arlette; Lan, Annaig; Andriamihaja, Mireille; Wilkanowicz, Sabina; Benetti, Pierre-Henri; Tomé, Daniel; Sanz, Yolanda; Blachier, Francois; Davila-Gay, Anne-Marie

    2014-01-01

    High-protein diets are used for body weight reduction, but consequences on the large intestine ecosystem are poorly known. Here, rats were fed for 15 days with either a normoproteic diet (NP, 14% protein) or a hyperproteic-hypoglucidic isocaloric diet (HP, 53% protein). Cecum and colon were recovered for analysis. Short- and branched-chain fatty acids, as well as lactate, succinate, formate, and ethanol contents, were markedly increased in the colonic luminal contents of HP rats (P < 0.05 or ...

  10. Cinematography of weakly - luminous transient phenomena using image converters; Cinematographie de phenomenes transitoires faiblement lumineux a l'aide d'amplificateurs de luminance

    Energy Technology Data Exchange (ETDEWEB)

    Stevenin, P.; Jacquot, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires. Services de Physique Appliquee, Service d' Ionique Generale

    1966-07-01

    After a review on the physical of optical informations emitted by a light source of weak intensity and short duration, the authors describe a high gain device by associating two image converters. The present specifications are given in the domain of high speed cinematography and spectrometry. (authors) [French] Apres avoir rappele la limitation d'origine physique du nombre d'informations optiques en provenance d'une source lumineuse de faible intensite et de courte duree, on decrit un appareillage a haut gain associant deux amplificateurs de luminance. On donne les performances actuelles du dispositif dans le domaine de la cinematographie et de la spectrometrie ultra-rapides. (auteurs)

  11. Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal-Like, Luminal A, and Luminal B Breast Cancers

    Science.gov (United States)

    2017-10-01

    adaptive focused acoustics shearing. Status: Ongoing, we have optimized conditions to process FFPE specimens. All quality control measures are in...in progress. Page 5 BODY: Task 1. Develop Interview Instrument , Other Study Materials, and Tracking System, Months 1-3, completed under Dr. Li’s...supervision at Fred Hutchinson Cancer Research Center (FHCRC): a. Refinement of interview instrument , Months 1-2: The telephone interview that will

  12. Advancing Our Understanding of the Etiologies and Mutational Landscapes of Basal Like, Luminal A, and Luminal B Breast Cancers

    Science.gov (United States)

    2016-10-01

    5-45, completed under Dr. Li’s supervision at FHCRC: a. Identification of controls, Months 5-45: General population controls with no prior history ...sequencing and analysis will be validated by SYBR Green based QPCR using Page 11 primers designed using Primer 3 to encompass the fusion junction on a...pools of multiplexed PCR products resequenced on Illumina next-generation sequencing equipment, we will screen any recurrently mutated gene appearing

  13. Clustering of agricultural enterprises

    Directory of Open Access Journals (Sweden)

    Michaela Beranová

    2013-01-01

    Full Text Available Agricultural business is a very specific branch which is characterized by very low financial performance while this characteristic is given mainly by external factors as market pricing of agricultural commodities on one side, and production costs of agricultural commodities on the other side. This way, agricultural enterprises recognize negative values of gross margin in the Profit and Loss Statement but positive value of operating profit after even there are items of costs which are deducted. These results are derived from agricultural production subsidies which are recognized as income in the P/L Statement. In connection with this fact, the government subsidies are a substantial component of financial performance of agricultural enterprises.Primary research proceeded on the statistical sample of one hundred agricultural companies, has shown that also other specifics influencing financial performance of these businesses exist here. In order to determine the influences, the cluster analysis has been applied at using more than 10 variables. This approach has led to construction of clusters (groups of agricultural business entities with different characteristics of the group. The objective of this paper is to identify the main determinants of financial performance of agricultural enterprises and to determine their influences under different economic characteristics of these business entities. For this purpose, the regression analysis has been subsequently applied on the groups of companies coming out from the cluster analysis. Besides the operating profit which is the main driving force of financial performance measured with the economic value added (EVA in agricultural enterprises, also capital structure and cost of capital have been observed as very strong influences on financial performance but these factors have different directions of their influence on the economic value added under different financial characteristics of agricultural

  14. The cluster bootstrap consistency in generalized estimating equations

    KAUST Repository

    Cheng, Guang

    2013-03-01

    The cluster bootstrap resamples clusters or subjects instead of individual observations in order to preserve the dependence within each cluster or subject. In this paper, we provide a theoretical justification of using the cluster bootstrap for the inferences of the generalized estimating equations (GEE) for clustered/longitudinal data. Under the general exchangeable bootstrap weights, we show that the cluster bootstrap yields a consistent approximation of the distribution of the regression estimate, and a consistent approximation of the confidence sets. We also show that a computationally more efficient one-step version of the cluster bootstrap provides asymptotically equivalent inference. © 2012.

  15. Stopping of hypervelocity clusters in solids

    International Nuclear Information System (INIS)

    Anders, Christian; Ziegenhain, Gerolf; Urbassek, Herbert M; Bringa, Eduardo M

    2011-01-01

    Using molecular-dynamics simulations, we study the processes underlying the stopping of energetic clusters upon impact in matter. We investigate self-bombardment of both a metallic (Cu) and a van-der-Waals bonded (frozen Ar) target. Clusters with sizes up to N = 10 4 atoms and with energies per atom of E/N = 0.1-1600 eV atom -1 were studied. We find that the stopping force exerted on a cluster follows an N 2/3 -dependence with cluster size N; thus large clusters experience less stopping than equi-velocity atoms. In the course of being stopped, the cluster is strongly deformed and attains a roughly pancake shape. Due to the cluster inertia, maximum deformation occurs later than the maximum stopping force. The time scale of projectile stopping is set by t 0 , the time the cluster needs to cover its own diameter before impacting the target; it thus depends on both cluster size and velocity. The time when the cluster experiences its maximum stopping force is around (0.7-0.8)t 0 . We find that the cluster is deformed with huge strain rates of around 1/2t 0 ; this amounts to 10 11 -10 13 s -1 for the cases studied here. (paper)

  16. Alpha condensates and nonlocalized cluster structures

    International Nuclear Information System (INIS)

    Funaki, Yasuro

    2014-01-01

    We discuss a container structure for non-gaslike cluster states, in which single Tohsaki-Horiuchi-Schuck-ROpke (THSR) wave functions are shown to be almost 100% equivalent to the full solutions of the corresponding RGM/GCM equations, for the inversion doublet band states in 20 Ne, α-linear-chain states, and α + α + A cluster states in 9 Λ Be. The recognition of the fact that the THSR wave function describes well not only gaslike cluster states but also non-gaslike cluster states is a recent remarkable development of nuclear cluster physics. This fact tells us that the cluster structure is composed of cluster-mean-field motion under the constraint of inter-cluster Pauli repulsion, in which we call the cluster-mean-field potential the container. We demonstrate that the evolution of the cluster structure of a nucleus is governed by the size parameter of the cluster-mean-field potential (container), for 16 O nucleus

  17. Efficient clustering aggregation based on data fragments.

    Science.gov (United States)

    Wu, Ou; Hu, Weiming; Maybank, Stephen J; Zhu, Mingliang; Li, Bing

    2012-06-01

    Clustering aggregation, known as clustering ensembles, has emerged as a powerful technique for combining different clustering results to obtain a single better clustering. Existing clustering aggregation algorithms are applied directly to data points, in what is referred to as the point-based approach. The algorithms are inefficient if the number of data points is large. We define an efficient approach for clustering aggregation based on data fragments. In this fragment-based approach, a data fragment is any subset of the data that is not split by any of the clustering results. To establish the theoretical bases of the proposed approach, we prove that clustering aggregation can be performed directly on data fragments under two widely used goodness measures for clustering aggregation taken from the literature. Three new clustering aggregation algorithms are described. The experimental results obtained using several public data sets show that the new algorithms have lower computational complexity than three well-known existing point-based clustering aggregation algorithms (Agglomerative, Furthest, and LocalSearch); nevertheless, the new algorithms do not sacrifice the accuracy.

  18. Extra Luminal Entrapment of Guide Wire; A Rare Complication of Central Venous Catheter Placement in Right Internal Jugular Vein.

    Science.gov (United States)

    Ansari, Md Abu Masud; Kumar, Naveen; Kumar, Shailesh; Kumari, Sarita

    2016-10-01

    Central venous Catheterization (CVC) is a commonly performed procedure for venous access. It is associated with several complications. We report a rare case of extra luminal entrapment of guide wire during CVC placement in right jugular vein. We report a case of 28 years old female patient presented in our emergency with history of entrapped guide wire in right side of neck during CVC. X-ray showed coiling of guide wire in neck. CT Angiography showed guide wire coursing in between common carotid artery and internal jugular vein (IJV), closely abutting the wall of both vessels. The guide wire was coiled with end coursing behind the esophageal wall. Guide wire was removed under fluoroscopic guide manipulation under local anesthesia. We want to emphasize that even though CVC placement is common and simple procedure, serious complication can occur in hands of untrained operator. The procedure should be performed under supervision, if done by trainee. Force should never be applied to advance the guide wire if resistance is encountered.

  19. Transcranial Doppler study in patients with cluster headache

    African Journals Online (AJOL)

    Soleiman A.M. Tahoon

    2013-03-11

    Mar 11, 2013 ... ities and vasoreactivity in cluster headache patients as baseline values and after ... Peer review under responsibility of Alexandria University Faculty of. Medicine. .... Dahl A, Russel D, Nyberg-Hansen R, Rootwelt K. Cluster.

  20. The CfA-Rosat Survey of Distant Clusters of Galaxies

    Science.gov (United States)

    McNamara, Brian

    1998-01-01

    We (Vikhlinin, McNamara, Forman, Jones, Hornstrup, Quintana) have completed a new survey of distant clusters of galaxies, which we use to to study cluster evolution over cosmological timescales. The clusters were identified as extended X-ray sources in 650 ROSAT PSPC images of high Galactic latitude fields. Our catalog of approximately 230 extended X-ray sources covers 160 square degrees on the sky. Ours is the largest of the several ROSAT serendipitous cluster surveys in progress (e.g. SHARC, Rosati, WARPS etc.). Using V,R,I imagery obtained at several observatories, we find that greater than 90% of the X-ray sources are associated with distant clusters of galaxies. We have obtained spectroscopic redshifts for nearly 80 clusters in our catalog, and we have measured photometric redshifts for the remaining clusters. Our sample contains more than 20 clusters at z > 0.5. I will discuss the logN-logS relationship for our clusters. Because our large survey area, we are able to confirm the evolution of the most luminous distant clusters first seen in the Einstein Extended Medium Sensitivity Survey. In addition, I will discuss the relationships between optical richness, core radius, and X-ray luminosity for distant, X-ray-selected clusters.

  1. What Makes Clusters Decline?

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter; Park, Eun Kyung

    2015-01-01

    Most studies on regional clusters focus on identifying factors and processes that make clusters grow. However, sometimes technologies and market conditions suddenly shift, and clusters decline. This paper analyses the process of decline of the wireless communication cluster in Denmark. The longit...... but being quick to withdraw in times of crisis....

  2. Clustering of correlated networks

    OpenAIRE

    Dorogovtsev, S. N.

    2003-01-01

    We obtain the clustering coefficient, the degree-dependent local clustering, and the mean clustering of networks with arbitrary correlations between the degrees of the nearest-neighbor vertices. The resulting formulas allow one to determine the nature of the clustering of a network.

  3. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  4. Fission approach to cluster radioactivity

    Indian Academy of Sciences (India)

    point Rt = Re + Rd. Here R0 is the radius of the parent nucleus, Re and Rd are the radii. 0. 0.5. 1 ... The standard r.m.s. deviations of log T values for 580 α emitters ... the total of 27 cluster emissions with standard deviations under one order of ...

  5. Candidate luminal B breast cancer genes identified by genome, gene expression and DNA methylation profiling.

    Directory of Open Access Journals (Sweden)

    Stéphanie Cornen

    Full Text Available Breast cancers (BCs of the luminal B subtype are estrogen receptor-positive (ER+, highly proliferative, resistant to standard therapies and have a poor prognosis. To better understand this subtype we compared DNA copy number aberrations (CNAs, DNA promoter methylation, gene expression profiles, and somatic mutations in nine selected genes, in 32 luminal B tumors with those observed in 156 BCs of the other molecular subtypes. Frequent CNAs included 8p11-p12 and 11q13.1-q13.2 amplifications, 7q11.22-q34, 8q21.12-q24.23, 12p12.3-p13.1, 12q13.11-q24.11, 14q21.1-q23.1, 17q11.1-q25.1, 20q11.23-q13.33 gains and 6q14.1-q24.2, 9p21.3-p24,3, 9q21.2, 18p11.31-p11.32 losses. A total of 237 and 101 luminal B-specific candidate oncogenes and tumor suppressor genes (TSGs presented a deregulated expression in relation with their CNAs, including 11 genes previously reported associated with endocrine resistance. Interestingly, 88% of the potential TSGs are located within chromosome arm 6q, and seven candidate oncogenes are potential therapeutic targets. A total of 100 candidate oncogenes were validated in a public series of 5,765 BCs and the overexpression of 67 of these was associated with poor survival in luminal tumors. Twenty-four genes presented a deregulated expression in relation with a high DNA methylation level. FOXO3, PIK3CA and TP53 were the most frequent mutated genes among the nine tested. In a meta-analysis of next-generation sequencing data in 875 BCs, KCNB2 mutations were associated with luminal B cases while candidate TSGs MDN1 (6q15 and UTRN (6q24, were mutated in this subtype. In conclusion, we have reported luminal B candidate genes that may play a role in the development and/or hormone resistance of this aggressive subtype.

  6. Assessment of atherosclerotic luminal narrowing of coronary arteries based on morphometrically generated visual guides.

    Science.gov (United States)

    Barth, Rolf F; Kellough, David A; Allenby, Patricia; Blower, Luke E; Hammond, Scott H; Allenby, Greg M; Buja, L Maximilian

    Determination of the degree of stenosis of atherosclerotic coronary arteries is an important part of postmortem examination of the heart, but, unfortunately, estimation of the degree of luminal narrowing can be imprecise and tends to be approximations. Visual guides can be useful to assess this, but earlier attempts to develop such guides did not employ digital technology. Using this approach, we have developed two computer-generated morphometric guides to estimate the degree of luminal narrowing of atherosclerotic coronary arteries. The first is based on symmetric or eccentric circular or crescentic narrowing of the vessel lumen and the second on either slit-like or irregularly shaped narrowing of the vessel lumens. Using the Aperio ScanScope XT at a magnification of 20× we created digital whole-slide images of 20 representative microscopic cross sections of the left anterior descending (LAD) coronary artery, stained with either hematoxylin and eosin (H&E) or Movat's pentachrome stain. These cross sections illustrated a variety of luminal profiles and degrees of stenosis. Three representative types of images were selected and a visual guide was constructed with Adobe Photoshop CS5. Using the "Scale" and "Measurement" tools, we created a series of representations of stenosis with luminal cross sections depicting 20%, 40%, 60%, 70%, 80%, and 90% occlusion of the LAD branch. Four pathologists independently reviewed and scored the degree of atherosclerotic luminal narrowing based on our visual guides. In addition, digital technology was employed to determine the degree of narrowing by measuring the cross-sectional area of the 20 microscopic sections of the vessels, first assuming no narrowing and then comparing this to the percent of narrowing determined by precise measurement. Two of the observers were very experienced general autopsy pathologists, one was a first-year pathology resident on his first rotation on the autopsy service, and the fourth observer was a

  7. Core condensation in heavy halos: a two-stage theory for galaxy formation and clustering

    Energy Technology Data Exchange (ETDEWEB)

    White, S D.M.; Rees, M J [Cambridge Univ. Inst. of Astronomy (UK)

    1978-05-01

    It is suggested that most of the material in the Universe condensed at an early epoch into small 'dark' objects. Irrespective of their nature, these objects must subsequently have undergone hierarchical clustering, whose present scale is inferred from the large-scale distribution of galaxies. As each stage of the hierarchy forms and collapses, relaxation effects wipe out its substructure, and to a self-similar distribution of bound masses. The entire luminous content of galaxies, however, results from the cooling and fragmentation of residual gas within the transient potential wells provided by the dark matter. Every galaxy thus forms as a concentrated luminous core embedded in an extensive dark halo. The observed sizes of galaxies and their survival through later stages of the hierarchy seem inexplicable without invoking substantial dissipation; this dissipation allows the galaxies to become sufficiently concentrated to survive the disruption of their halos in groups and clusters of galaxies. A specific model is proposed in which ..cap omega.. approximately equals 0.2, the dark matter makes up 80 per cent of the total mass, and half the residual gas has been converted into luminous galaxies by the present time. This model is consistent with the inferred proportions of dark matter and gas in rich clusters, with the observed luminosity density of the Universe and with the observed radii of galaxies; further, it predicts the characteristic luminosities of bright galaxies can give a luminosity function of the observed shape.

  8. Cluster ion beam facilities

    International Nuclear Information System (INIS)

    Popok, V.N.; Prasalovich, S.V.; Odzhaev, V.B.; Campbell, E.E.B.

    2001-01-01

    A brief state-of-the-art review in the field of cluster-surface interactions is presented. Ionised cluster beams could become a powerful and versatile tool for the modification and processing of surfaces as an alternative to ion implantation and ion assisted deposition. The main effects of cluster-surface collisions and possible applications of cluster ion beams are discussed. The outlooks of the Cluster Implantation and Deposition Apparatus (CIDA) being developed in Guteborg University are shown

  9. Immunohistochemical localisation of keratin and luminal epithelial antigen in myoepithelial and luminal epithelial cells of human mammary and salivary gland tumours.

    Science.gov (United States)

    Nathrath, W B; Wilson, P D; Trejdosiewicz, L K

    1982-01-01

    Rabbit antisera to human 40-63 000 MW epidermal keratin, one batch with restricted distribution of reactivity from an initial (aK1) and one with "broad spectrum" distribution of reactivity from a late bleeding (aK), and to "luminal epithelial antigen" (aLEA) were applied to formalin fixed paraffin embedded sections of human normal and neoplastic mammary and salivary glands using an indirect immunoperoxidase method. aK1 reacted with myoepithelial cells, aLEA with luminal epithelial cells and aK with both cell types in normal mammary and salivary gland. In breast carcinomas the majority of intraluminal and infiltrating carcinoma cells reacted with aLEA but not with aK1 which reacted only with surrounding myoepithelial cells. aK reacted with both myoepithelial cells and with intraluminal and infiltrating tumour cells. In the salivary gland adenomas the majority of cells reacted with aK, and those cells arranged in a tubular fashion reacted with aLEA.

  10. PREFACE: Nuclear Cluster Conference; Cluster'07

    Science.gov (United States)

    Freer, Martin

    2008-05-01

    The Cluster Conference is a long-running conference series dating back to the 1960's, the first being initiated by Wildermuth in Bochum, Germany, in 1969. The most recent meeting was held in Nara, Japan, in 2003, and in 2007 the 9th Cluster Conference was held in Stratford-upon-Avon, UK. As the name suggests the town of Stratford lies upon the River Avon, and shortly before the conference, due to unprecedented rainfall in the area (approximately 10 cm within half a day), lay in the River Avon! Stratford is the birthplace of the `Bard of Avon' William Shakespeare, and this formed an intriguing conference backdrop. The meeting was attended by some 90 delegates and the programme contained 65 70 oral presentations, and was opened by a historical perspective presented by Professor Brink (Oxford) and closed by Professor Horiuchi (RCNP) with an overview of the conference and future perspectives. In between, the conference covered aspects of clustering in exotic nuclei (both neutron and proton-rich), molecular structures in which valence neutrons are exchanged between cluster cores, condensates in nuclei, neutron-clusters, superheavy nuclei, clusters in nuclear astrophysical processes and exotic cluster decays such as 2p and ternary cluster decay. The field of nuclear clustering has become strongly influenced by the physics of radioactive beam facilities (reflected in the programme), and by the excitement that clustering may have an important impact on the structure of nuclei at the neutron drip-line. It was clear that since Nara the field had progressed substantially and that new themes had emerged and others had crystallized. Two particular topics resonated strongly condensates and nuclear molecules. These topics are thus likely to be central in the next cluster conference which will be held in 2011 in the Hungarian city of Debrechen. Martin Freer Participants and Cluster'07

  11. Compact RGBY light sources with high luminance for laser display applications

    Science.gov (United States)

    Paschke, Katrin; Blume, Gunnar; Werner, Nils; Müller, André; Sumpf, Bernd; Pohl, Johannes; Feise, David; Ressel, Peter; Sahm, Alexander; Bege, Roland; Hofmann, Julian; Jedrzejczyk, Daniel; Tränkle, Günther

    2018-02-01

    Watt-class visible laser light with a high luminance can be created with high-power GaAs-based lasers either directly in the red spectral region or using single-pass second harmonic generation (SHG) for the colors in the blue-yellow spectral region. The concepts and results of red- and near infrared-emitting distributed Bragg reflector tapered lasers and master oscillator power amplifier systems as well as their application for SHG bench-top experiments and miniaturized modules are presented. Examples of these high-luminance light sources aiming at different applications such as flying spot display or holographic 3D cinema are discussed in more detail. The semiconductor material allows an easy adaptation of the wavelength allowing techniques such as six-primary color 3D projection or color space enhancement by adding a fourth yellow color.

  12. Colour and luminance contrasts predict the human detection of natural stimuli in complex visual environments.

    Science.gov (United States)

    White, Thomas E; Rojas, Bibiana; Mappes, Johanna; Rautiala, Petri; Kemp, Darrell J

    2017-09-01

    Much of what we know about human colour perception has come from psychophysical studies conducted in tightly-controlled laboratory settings. An enduring challenge, however, lies in extrapolating this knowledge to the noisy conditions that characterize our actual visual experience. Here we combine statistical models of visual perception with empirical data to explore how chromatic (hue/saturation) and achromatic (luminant) information underpins the detection and classification of stimuli in a complex forest environment. The data best support a simple linear model of stimulus detection as an additive function of both luminance and saturation contrast. The strength of each predictor is modest yet consistent across gross variation in viewing conditions, which accords with expectation based upon general primate psychophysics. Our findings implicate simple visual cues in the guidance of perception amidst natural noise, and highlight the potential for informing human vision via a fusion between psychophysical modelling and real-world behaviour. © 2017 The Author(s).

  13. Automatic Supervision of Temperature, Humidity, and Luminance with an Assistant Personal Robot

    Directory of Open Access Journals (Sweden)

    Jordi Palacín

    2017-01-01

    Full Text Available Smart environments and Ambient Intelligence (AmI technologies are defining the future society where energy optimization and intelligent management are essential for a sustainable advance. Mobile robotics is also making an important contribution to this advance with the integration of sensors and intelligent processing algorithms. This paper presents the application of an Assistant Personal Robot (APR as an autonomous agent for temperature, humidity, and luminance supervision in human-frequented areas. The robot multiagent capabilities allow gathering sensor information while exploring or performing specific tasks and then verifying human comfortability levels. The proposed methodology creates information maps with the distribution of temperature, humidity, and luminance and interprets such information in terms of comfort and warns about corrective actuations if required.

  14. The Dichotomous Cosmology with a Static Material World and Expanding Luminous World

    Directory of Open Access Journals (Sweden)

    Heymann Y.

    2014-07-01

    Full Text Available The dichotomous cosmology is an alternative to the expanding Universe theory, and consists of a static matter Universe, where cosmological redshifts are explained by a tired-light model with an expanding luminous world. In this model the Hubble constant is also the photon energy decay rate, and the luminous world i s expanding at a constant rate as in de Sitter cosmology for an empty Universe. The present model explains both the luminosity distance versus redshift relationship of supernovae Ia, and ageing of spectra observed with the stretching of supernovae light curves. Furthermore, it is consistent with a radiation energy density factor (1 + z 4 inferred from the Cosmic Microwave Background Radiation.

  15. Radioisotope treatment for benign strictures of non-vascular luminal organs

    International Nuclear Information System (INIS)

    Shin, Ji Hoon

    2006-01-01

    Tissue hyperplasia in one of the most frequently encountered complications when self-expanding stents are placed in benign non-vascular luminal organ strictures, thus causing of the lumen. The investigators postulated that ionizing irradiation could be applied to prevent restenosis caused by tissue hyperplasia in non-vascular luminal organs as it reduced coronary or peripheral arterial narrowing successfully. The authors combined β-irradiation using 188 Re-MAG 3 solution with balloon for animal and clinical studies because this new treatment approach had the advantages such as low penetration depth of β-ray, self-centering irradiation, and mechanical effect of balloon dilation over using γ-irradiation with afterloading devices. In this article, the concept and mechanism of radioisotope balloon dilation, and animal and clinical studies using radioisotope balloon dilation are reviewed

  16. LITHIUM-RICH GIANTS IN GLOBULAR CLUSTERS

    Energy Technology Data Exchange (ETDEWEB)

    Kirby, Evan N.; Cohen, Judith G. [California Institute of Technology, 1200 E. California Boulevard, MC 249-17, Pasadena, CA 91125 (United States); Guhathakurta, Puragra [UCO/Lick Observatory and Department of Astronomy and Astrophysics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States); Zhang, Andrew J. [The Harker School, 500 Saratoga Avenue, San Jose, CA 95129 (United States); Hong, Jerry [Palo Alto High School, 50 Embarcadero Road, Palo Alto, CA, 94301 (United States); Guo, Michelle [Stanford University, 450 Serra Mall, Stanford, CA 94305 (United States); Guo, Rachel [Irvington High School, 41800 Blacow Road, Fremont, CA 94538 (United States); Cunha, Katia [Observatório Nacional, São Cristóvão Rio de Janeiro (Brazil)

    2016-03-10

    Although red giants deplete lithium on their surfaces, some giants are Li-rich. Intermediate-mass asymptotic giant branch (AGB) stars can generate Li through the Cameron–Fowler conveyor, but the existence of Li-rich, low-mass red giant branch (RGB) stars is puzzling. Globular clusters are the best sites to examine this phenomenon because it is straightforward to determine membership in the cluster and to identify the evolutionary state of each star. In 72 hours of Keck/DEIMOS exposures in 25 clusters, we found four Li-rich RGB and two Li-rich AGB stars. There were 1696 RGB and 125 AGB stars with measurements or upper limits consistent with normal abundances of Li. Hence, the frequency of Li-richness in globular clusters is (0.2 ± 0.1)% for the RGB, (1.6 ± 1.1)% for the AGB, and (0.3 ± 0.1)% for all giants. Because the Li-rich RGB stars are on the lower RGB, Li self-generation mechanisms proposed to occur at the luminosity function bump or He core flash cannot explain these four lower RGB stars. We propose the following origin for Li enrichment: (1) All luminous giants experience a brief phase of Li enrichment at the He core flash. (2) All post-RGB stars with binary companions on the lower RGB will engage in mass transfer. This scenario predicts that 0.1% of lower RGB stars will appear Li-rich due to mass transfer from a recently Li-enhanced companion. This frequency is at the lower end of our confidence interval.

  17. Orientation-specific contextual modulation of the fMRI BOLD response to luminance and chromatic gratings in human visual cortex.

    Science.gov (United States)

    McDonald, J Scott; Seymour, Kiley J; Schira, Mark M; Spehar, Branka; Clifford, Colin W G

    2009-05-01

    The responses of orientation-selective neurons in primate visual cortex can be profoundly affected by the presence and orientation of stimuli falling outside the classical receptive field. Our perception of the orientation of a line or grating also depends upon the context in which it is presented. For example, the perceived orientation of a grating embedded in a surround tends to be repelled from the predominant orientation of the surround. Here, we used fMRI to investigate the basis of orientation-specific surround effects in five functionally-defined regions of visual cortex: V1, V2, V3, V3A/LO1 and hV4. Test stimuli were luminance-modulated and isoluminant gratings that produced responses similar in magnitude. Less BOLD activation was evident in response to gratings with parallel versus orthogonal surrounds across all the regions of visual cortex investigated. When an isoluminant test grating was surrounded by a luminance-modulated inducer, the degree of orientation-specific contextual modulation was no larger for extrastriate areas than for V1, suggesting that the observed effects might originate entirely in V1. However, more orientation-specific modulation was evident in extrastriate cortex when both test and inducer were luminance-modulated gratings than when the test was isoluminant; this difference was significant in area V3. We suggest that the pattern of results in extrastriate cortex may reflect a refinement of the orientation-selectivity of surround suppression specific to the colour of the surround or, alternatively, processes underlying the segmentation of test and inducer by spatial phase or orientation when no colour cue is available.

  18. Luminal flow amplifies stent-based drug deposition in arterial bifurcations.

    Directory of Open Access Journals (Sweden)

    Vijaya B Kolachalama

    2009-12-01

    Full Text Available Treatment of arterial bifurcation lesions using drug-eluting stents (DES is now common clinical practice and yet the mechanisms governing drug distribution in these complex morphologies are incompletely understood. It is still not evident how to efficiently determine the efficacy of local drug delivery and quantify zones of excessive drug that are harbingers of vascular toxicity and thrombosis, and areas of depletion that are associated with tissue overgrowth and luminal re-narrowing.We constructed two-phase computational models of stent-deployed arterial bifurcations simulating blood flow and drug transport to investigate the factors modulating drug distribution when the main-branch (MB was treated using a DES. Simulations predicted extensive flow-mediated drug delivery in bifurcated vascular beds where the drug distribution patterns are heterogeneous and sensitive to relative stent position and luminal flow. A single DES in the MB coupled with large retrograde luminal flow on the lateral wall of the side-branch (SB can provide drug deposition on the SB lumen-wall interface, except when the MB stent is downstream of the SB flow divider. In an even more dramatic fashion, the presence of the SB affects drug distribution in the stented MB. Here fluid mechanic effects play an even greater role than in the SB especially when the DES is across and downstream to the flow divider and in a manner dependent upon the Reynolds number.The flow effects on drug deposition and subsequent uptake from endovascular DES are amplified in bifurcation lesions. When only one branch is stented, a complex interplay occurs - drug deposition in the stented MB is altered by the flow divider imposed by the SB and in the SB by the presence of a DES in the MB. The use of DES in arterial bifurcations requires a complex calculus that balances vascular and stent geometry as well as luminal flow.

  19. Intratumoral estrogen production and actions in luminal A type invasive lobular and ductal carcinomas.

    Science.gov (United States)

    Takagi, Mayu; Miki, Yasuhiro; Miyashita, Minoru; Hata, Shuko; Yoda, Tomomi; Hirakawa, Hisashi; Sagara, Yasuaki; Rai, Yoshiaki; Ohi, Yasuyo; Tamaki, Kentaro; Ishida, Takanori; Suzuki, Takashi; Ouchi, Noriaki; Sasano, Hironobu

    2016-02-01

    The great majority of invasive lobular carcinoma (ILC) is estrogen-dependent luminal A type carcinoma but the details of estrogen actions and its intratumoral metabolism have not been well studied compared to invasive ductal carcinoma (IDC). We first immunolocalized estrogen-related enzymes including estrogen sulfotransferase (EST), estrogen sulfatase (STS), 17β-hydroxysteroid dehydrogenase (HSD) 1/2, and aromatase. We then evaluated the tissue concentrations of estrogens in ILC and IDC and subsequently estrogen-responsive gene profiles in these tumors in order to explore the possible differences and/or similarity of intratumoral estrogen environment of these two breast cancer subtypes. The status of STS and 17βHSD1 was significantly lower in ILCs than IDCs (p = 0.022 and p < 0.0001), but that of EST and 17βHSD2 vice versa (p < 0.0001 and p = 0.0106). In ILCs, tissue concentrations of estrone and estradiol were lower than those in IDCs (p = 0.0709 and 0.069). In addition, the great majority of estrogen response genes tended to be lower in ILCs. Among those genes above, FOXP1 was significantly higher in ILCs than in IDCs (p = 0.002). FOXP1 expression was reported to be significantly higher in relapse-free IDC patients treated with tamoxifen. Therefore, tamoxifen may be considered an option of endocrine therapy for luminal A type ILC patients. This is the first study to demonstrate the detailed and comprehensive status of intratumoral production and metabolism of estrogens and the status of estrogen response genes in luminal A-like ILC with comparison to those in luminal A-like IDCs.

  20. The uncultured luminous symbiont of Anomalops katoptron (Beryciformes: Anomalopidae) represents a new bacterial genus.

    Science.gov (United States)

    Hendry, Tory A; Dunlap, Paul V

    2011-12-01

    Flashlight fishes (Beryciformes: Anomalopidae) harbor luminous symbiotic bacteria in subocular light organs and use the bacterial light for predator avoidance, feeding, and communication. Despite many attempts anomalopid symbionts have not been brought into laboratory culture, which has restricted progress in understanding their phylogenetic relationships with other luminous bacteria, identification of the genes of their luminescence system, as well as the nature of their symbiotic interactions with their fish hosts. To begin addressing these issues, we used culture-independent analysis of the bacteria symbiotic with the anomalopid fish, Anomalops katoptron, to characterize the phylogeny of the bacteria and to identify the genes of their luminescence system including those involved in the regulation of luminescence. Analysis of the 16S rRNA, atpA, gapA, gyrB, pyrH, recA, rpoA, and topA genes resolved the A. katoptron symbionts as a clade nested within and deeply divergent from other members of Vibrionaceae. The bacterial luminescence (lux) genes were identified as a contiguous set (luxCDABEG), as found for the lux operons of other luminous bacteria. Phylogenetic analysis based on the lux genes confirmed the housekeeping gene phylogenetic placement. Furthermore, genes flanking the lux operon in the A. katoptron symbionts differed from those flanking lux operons of other genera of luminous bacteria. We therefore propose the candidate name Candidatus Photodesmus (Greek: photo = light, desmus = servant) katoptron for the species of bacteria symbiotic with A. katoptron. Results of a preliminary genomic analysis for genes regulating luminescence in other bacteria identified only a Vibrio harveyi-type luxR gene. These results suggest that expression of the luminescence system might be continuous in P. katoptron. Copyright © 2011 Elsevier Inc. All rights reserved.

  1. Profiling Local Optima in K-Means Clustering: Developing a Diagnostic Technique

    Science.gov (United States)

    Steinley, Douglas

    2006-01-01

    Using the cluster generation procedure proposed by D. Steinley and R. Henson (2005), the author investigated the performance of K-means clustering under the following scenarios: (a) different probabilities of cluster overlap; (b) different types of cluster overlap; (c) varying samples sizes, clusters, and dimensions; (d) different multivariate…

  2. Management of cluster headache

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer C; Jensen, Rigmor H

    2012-01-01

    The prevalence of cluster headache is 0.1% and cluster headache is often not diagnosed or misdiagnosed as migraine or sinusitis. In cluster headache there is often a considerable diagnostic delay - an average of 7 years in a population-based survey. Cluster headache is characterized by very severe...... or severe orbital or periorbital pain with a duration of 15-180 minutes. The cluster headache attacks are accompanied by characteristic associated unilateral symptoms such as tearing, nasal congestion and/or rhinorrhoea, eyelid oedema, miosis and/or ptosis. In addition, there is a sense of restlessness...... and agitation. Patients may have up to eight attacks per day. Episodic cluster headache (ECH) occurs in clusters of weeks to months duration, whereas chronic cluster headache (CCH) attacks occur for more than 1 year without remissions. Management of cluster headache is divided into acute attack treatment...

  3. Symmetries of cluster configurations

    International Nuclear Information System (INIS)

    Kramer, P.

    1975-01-01

    A deeper understanding of clustering phenomena in nuclei must encompass at least two interrelated aspects of the subject: (A) Given a system of A nucleons with two-body interactions, what are the relevant and persistent modes of clustering involved. What is the nature of the correlated nucleon groups which form the clusters, and what is their mutual interaction. (B) Given the cluster modes and their interaction, what systematic patterns of nuclear structure and reactions emerge from it. Are there, for example, families of states which share the same ''cluster parents''. Which cluster modes are compatible or exclude each other. What quantum numbers could characterize cluster configurations. There is no doubt that we can learn a good deal from the experimentalists who have discovered many of the features relevant to aspect (B). Symmetries specific to cluster configurations which can throw some light on both aspects of clustering are discussed

  4. Relative efficiency and sample size for cluster randomized trials with variable cluster sizes.

    Science.gov (United States)

    You, Zhiying; Williams, O Dale; Aban, Inmaculada; Kabagambe, Edmond Kato; Tiwari, Hemant K; Cutter, Gary

    2011-02-01

    The statistical power of cluster randomized trials depends on two sample size components, the number of clusters per group and the numbers of individuals within clusters (cluster size). Variable cluster sizes are common and this variation alone may have significant impact on study power. Previous approaches have taken this into account by either adjusting total sample size using a designated design effect or adjusting the number of clusters according to an assessment of the relative efficiency of unequal versus equal cluster sizes. This article defines a relative efficiency of unequal versus equal cluster sizes using noncentrality parameters, investigates properties of this measure, and proposes an approach for adjusting the required sample size accordingly. We focus on comparing two groups with normally distributed outcomes using t-test, and use the noncentrality parameter to define the relative efficiency of unequal versus equal cluster sizes and show that statistical power depends only on this parameter for a given number of clusters. We calculate the sample size required for an unequal cluster sizes trial to have the same power as one with equal cluster sizes. Relative efficiency based on the noncentrality parameter is straightforward to calculate and easy to interpret. It connects the required mean cluster size directly to the required sample size with equal cluster sizes. Consequently, our approach first determines the sample size requirements with equal cluster sizes for a pre-specified study power and then calculates the required mean cluster size while keeping the number of clusters unchanged. Our approach allows adjustment in mean cluster size alone or simultaneous adjustment in mean cluster size and number of clusters, and is a flexible alternative to and a useful complement to existing methods. Comparison indicated that we have defined a relative efficiency that is greater than the relative efficiency in the literature under some conditions. Our measure

  5. A Review of Subsequence Time Series Clustering

    Directory of Open Access Journals (Sweden)

    Seyedjamal Zolhavarieh

    2014-01-01

    Full Text Available Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies.

  6. A review of subsequence time series clustering.

    Science.gov (United States)

    Zolhavarieh, Seyedjamal; Aghabozorgi, Saeed; Teh, Ying Wah

    2014-01-01

    Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies.

  7. A Review of Subsequence Time Series Clustering

    Science.gov (United States)

    Teh, Ying Wah

    2014-01-01

    Clustering of subsequence time series remains an open issue in time series clustering. Subsequence time series clustering is used in different fields, such as e-commerce, outlier detection, speech recognition, biological systems, DNA recognition, and text mining. One of the useful fields in the domain of subsequence time series clustering is pattern recognition. To improve this field, a sequence of time series data is used. This paper reviews some definitions and backgrounds related to subsequence time series clustering. The categorization of the literature reviews is divided into three groups: preproof, interproof, and postproof period. Moreover, various state-of-the-art approaches in performing subsequence time series clustering are discussed under each of the following categories. The strengths and weaknesses of the employed methods are evaluated as potential issues for future studies. PMID:25140332

  8. Hybrid metal grid-polymer-carbon nanotube electrodes for high luminance organic light emitting diodes

    International Nuclear Information System (INIS)

    Sam, F Laurent M; Dabera, G Dinesha M R; Lai, Khue T; Mills, Christopher A; Rozanski, Lynn J; Silva, S Ravi P

    2014-01-01

    Organic light emitting diodes (OLEDs) incorporating grid transparent conducting electrodes (TCEs) with wide grid line spacing suffer from an inability to transfer charge carriers across the gaps in the grids to promote light emission in these areas. High luminance OLEDs fabricated using a hybrid TCE composed of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS PH1000) or regioregular poly(3-hexylthiophene)-wrapped semiconducting single-walled carbon nanotubes (rrP3HT-SWCNT) in combination with a nanometre thin gold grid are reported here. OLEDs fabricated using the hybrid gold grid/PH1000 TCE have a luminance of 18 000 cd m −2 at 9 V; the same as the reference indium tin oxide (ITO) OLED. The gold grid/rrP3HT-SWCNT OLEDs have a lower luminance of 8260 cd m −2 at 9 V, which is likely due to a rougher rrP3HT-SWCNT surface. These results demonstrate that the hybrid gold grid/PH1000 TCE is a promising replacement for ITO in future plastic electronics applications including OLEDs and organic photovoltaics. For applications where surface roughness is not critical, e.g. electrochromic devices or discharge of static electricity, the gold grid/rrP3HT-SWCNT hybrid TCE can be employed. (paper)

  9. Radiation properties of two types of luminous textile devices containing plastic optical fibers

    Science.gov (United States)

    Selm, Bärbel; Rothmaier, Markus

    2007-05-01

    Luminous textiles have the potential to satisfy a need for thin and flexible light diffusers for treatment of intraoral cancerous tissue. Plastic optical fibers (POF) with diameters of 250 microns and smaller are used to make the textiles luminous. Usually light is supplied to the optical fiber at both ends. On the textile surface light emission occurs in a woven structure via damaged straight POFs, whereas the embroidered structure radiates the light out of macroscopically bent POFs. We compared the optical properties of these two types of textile diffusers using red light laser for the embroidery and light emitting diode (LED) for the woven structure as light sources, and found efficiencies for the luminous areas of the two samples of 19 % (woven) and 32 % (embroidery), respectively. It was shown that the efficiency can be greatly improved using an aluminium backing. Additional scattering layers lower the fluence rate by around 30 %. To analyse the homogeneity we took a photo of the illuminated surface using a 3CCD camera and found, for both textiles, a slightly skewed distribution of the dark and bright pixels. The interquartile range of brightness distribution of the embroidery is more than double as the woven structure.

  10. Luminance and chromatic signals interact differently with melanopsin activation to control the pupil light response.

    Science.gov (United States)

    Barrionuevo, Pablo A; Cao, Dingcai

    2016-09-01

    Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin. These cells receive afferent inputs from rods and cones, which provide inputs to the postreceptoral visual pathways. It is unknown, however, how melanopsin activation is integrated with postreceptoral signals to control the pupillary light reflex. This study reports human flicker pupillary responses measured using stimuli generated with a five-primary photostimulator that selectively modulated melanopsin, rod, S-, M-, and L-cone excitations in isolation, or in combination to produce postreceptoral signals. We first analyzed the light adaptation behavior of melanopsin activation and rod and cones signals. Second, we determined how melanopsin is integrated with postreceptoral signals by testing with cone luminance, chromatic blue-yellow, and chromatic red-green stimuli that were processed by magnocellular (MC), koniocellular (KC), and parvocellular (PC) pathways, respectively. A combined rod and melanopsin response was also measured. The relative phase of the postreceptoral signals was varied with respect to the melanopsin phase. The results showed that light adaptation behavior for all conditions was weaker than typical Weber adaptation. Melanopsin activation combined linearly with luminance, S-cone, and rod inputs, suggesting the locus of integration with MC and KC signals was retinal. The melanopsin contribution to phasic pupil responses was lower than luminance contributions, but much higher than S-cone contributions. Chromatic red-green modulation interacted with melanopsin activation nonlinearly as described by a "winner-takes-all" process, suggesting the integration with PC signals might be mediated by a postretinal site.

  11. An analytical model for backscattered luminance in fog: comparisons with Monte Carlo computations and experimental results

    International Nuclear Information System (INIS)

    Taillade, Frédéric; Dumont, Eric; Belin, Etienne

    2008-01-01

    We propose an analytical model for backscattered luminance in fog and derive an expression for the visibility signal-to-noise ratio as a function of meteorological visibility distance. The model uses single scattering processes. It is based on the Mie theory and the geometry of the optical device (emitter and receiver). In particular, we present an overlap function and take the phase function of fog into account. The results of the backscattered luminance obtained with our analytical model are compared to simulations made using the Monte Carlo method based on multiple scattering processes. An excellent agreement is found in that the discrepancy between the results is smaller than the Monte Carlo standard uncertainties. If we take no account of the geometry of the optical device, the results of the model-estimated backscattered luminance differ from the simulations by a factor 20. We also conclude that the signal-to-noise ratio computed with the Monte Carlo method and our analytical model is in good agreement with experimental results since the mean difference between the calculations and experimental measurements is smaller than the experimental uncertainty

  12. Luminal DMSO: Effects on Detrusor and Urothelial/Lamina Propria Function

    Directory of Open Access Journals (Sweden)

    Katrina J. Smith

    2014-01-01

    Full Text Available DMSO is used as a treatment for interstitial cystitis and this study examined the effects of luminal DMSO treatment on bladder function and histology. Porcine bladder was incubated without (controls or with DMSO (50% applied to the luminal surface and the release of ATP, acetylcholine, and LDH assessed during incubation and in tissues strips after DMSO incubation. Luminally applied DMSO caused ATP, Ach, and LDH release from the urothelial surface during treatment, with loss of urothelial layers also evident histologically. In strips of urothelium/lamina propria from DMSO pretreated bladders the release of both ATP and Ach was depressed, while contractile responses to carbachol were enhanced. Detrusor muscle contractile responses to carbachol were not affected by DMSO pretreatment, but neurogenic responses to electrical field stimulation were enhanced. The presence of an intact urothelium/lamina propria inhibited detrusor contraction to carbachol by 53% and this inhibition was significantly reduced in DMSO pretreated tissues. Detection of LDH in the treatment medium suggests that DMSO permeabilised urothelial membranes causing leakage of cytosolic contents including ATP and Ach rather than enhancing release of these mediators. The increase in contractile response and high levels of ATP are consistent with initial flare up in IC/PBS symptoms after DMSO treatment.

  13. Epimorphin mediates mammary luminal morphogenesis through control of C/EBPbeta

    International Nuclear Information System (INIS)

    Hirai, Yohei; Radisky, Derek; Boudreau, Rosanne; Simian, Marina; Stevens, Mary E.; Oka, Yumiko; Takebe, Kyoko; Niwa, Shinichiro; Bissell, Mina J.

    2002-01-01

    We have previously shown that epimorphin, a protein expressed on the surface of myoepithelial and fibroblast cells of the mammary gland, acts as a multifunctional morphogen of mammary epithelial cells. Here, we present the molecular mechanism by which epimorphin mediates luminal morphogenesis. Treatment of cells with epimorphin to induce lumen formation greatly increases the overall expression of transcription factor CCAAT/enhancer binding protein beta (C/EBPbeta) and alters the relative expression of its two principal isoforms, LIP and LAP. These alterations were shown to be essential for the morphogenetic activities, as constitutive expression of LIP was sufficient to produce lumen formation, while constitutive expression of LAP blocked epimorphin-mediated luminal morphogenesis. Furthermore, in a transgenic mouse model in which epimorphin expression was expressed in an apolar fashion on the surface of mammary epithelial cells, we found increased expression of C/EBPbeta, increased relative expression of LIP to LAP, and enlarged ductal lumina. Together, our studies demonstrate a role for epimorphin in luminal morphogenesis through control of C/EBPbeta expression

  14. Id-1 is not expressed in the luminal epithelial cells of mammary glands

    International Nuclear Information System (INIS)

    Uehara, Norihisa; Chou, Yu-Chien; Galvez, Jose J; Candia, Paola de; Cardiff, Robert D; Benezra, Robert; Shyamala, Gopalan

    2003-01-01

    The family of inhibitor of differentiation/DNA binding (Id) proteins is known to regulate development in several tissues. One member of this gene family, Id-1, has been implicated in mammary development and carcinogenesis. Mammary glands contain various cell types, among which the luminal epithelial cells are primarily targeted for proliferation, differentiation and carcinogenesis. Therefore, to assess the precise significance of Id-1 in mammary biology and carcinogenesis, we examined its cellular localization in vivo using immunohistochemistry. Extracts of whole mammary glands from wild type and Id-1 null mutant mice, and tissue sections from paraffin-embedded mouse mammary glands from various developmental stages and normal human breast were subjected to immunoblot and immunohistochemical analyses, respectively. In both these procedures, an anti-Id-1 rabbit polyclonal antibody was used for detection of Id-1. In immunoblot analyses, using whole mammary gland extracts, Id-1 was detected. In immunohistochemical analyses, however, Id-1 was not detected in the luminal epithelial cells of mammary glands during any stage of development, but it was detected in vascular endothelial cells. Id-1 is not expressed in the luminal epithelial cells of mammary glands

  15. Luminal and basolateral uptake of insulin in isolated perfused, proximal tubules

    International Nuclear Information System (INIS)

    Nielsen, S.; Nielsen, J.T.; Christensen, E.I.

    1987-01-01

    The present study was performed to quantitate compare the luminal and the peritubular uptake of 125 I-insulin in isolated, perfused, proximal tubules from rabbit kidneys. 125 I-insulin was added in physiological concentrations to either the perfusate or the bath fluid for 30 min. The luminal uptake in 30 min averaged 0.76 pg/mm at physiological concentrations and 18.0 pg/mm at high insulin concentrations. About 15-41% of the absorbed insulin was digested and 125 I-insulin at physiological and high concentrations in the bath was 0.136 and 0.318 pg, respectively. The data indicates that insulin is bound/absorbed at the basolateral membranes both by a saturable specific mechanism and a nonspecific, nonsaturable mechanism. The basolateral absorption constituted 15.2 and 1.8% of the total tubular extraction of insulin at physiological and high insulin concentrations, respectively. Electron microscope autoradiography showed that, after luminal as well as basolateral endocytosis, insulin was exclusively accumulated in endocytic vacuoles and lysosomes

  16. Luminous and Variable Stars in M31 and M33. V. The Upper HR Diagram

    Energy Technology Data Exchange (ETDEWEB)

    Humphreys, Roberta M.; Davidson, Kris; Hahn, David [Minnesota Institute for Astrophysics, 116 Church St SE, University of Minnesota, Minneapolis, MN 55455 (United States); Martin, John C. [Barber Observatory, University of Illinois, Springfield, IL 62703 (United States); Weis, Kerstin, E-mail: roberta@umn.edu [Astronomical Institute, Ruhr-Universitaet Bochum (Germany)

    2017-07-20

    We present HR diagrams for the massive star populations in M31 and M33, including several different types of emission-line stars: the confirmed luminous blue variables (LBVs), candidate LBVs, B[e] supergiants, and the warm hypergiants. We estimate their apparent temperatures and luminosities for comparison with their respective massive star populations and evaluate the possible relationships of these different classes of evolved, massive stars, and their evolutionary state. Several of the LBV candidates lie near the LBV/S Dor instability strip that supports their classification. Most of the B[e] supergiants, however, are less luminous than the LBVs. Many are very dusty with the infrared flux contributing one-third or more to their total flux. They are also relatively isolated from other luminous OB stars. Overall, their spatial distribution suggests a more evolved state. Some may be post-RSGs (red supergiants) like the warm hypergiants, and there may be more than one path to becoming a B[e] star. There are sufficient differences in the spectra, luminosities, spatial distribution, and the presence or lack of dust between the LBVs and B[e] supergiants to conclude that one group does not evolve into the other.

  17. The effectiveness of a near-infrared vascular imaging device to support intravenous cannulation in children with dark skin color: a cluster randomized clinical trial.

    Science.gov (United States)

    van der Woude, Olga C P; Cuper, Natascha J; Getrouw, Chavalleh; Kalkman, Cor J; de Graaff, Jurgen C

    2013-06-01

    Poor vein visibility can make IV cannulation challenging in children with dark skin color. In the operating room, we studied the effectiveness of a near-infrared vascular imaging device (VascuLuminator) to facilitate IV cannulation in children with dark skin color. In the operating room of a general hospital in Curacao, all consecutive children (0-15 years of age) requiring IV cannulation were included in a pragmatic cluster randomized clinical trial. The VascuLuminator was made available to anesthesiologists at the operating complex in randomized clusters of 1 week. Success at first attempt was 63% (27/43, 95% confidence interval [CI], 47%-77%) in the VascuLuminator group vs 51% (23 of 45 patients, 95% CI, 36%-66%) in the control group (P = 0.27). Median time to successful cannulation was 53 seconds (interquartile range: 34-154) in the VascuLuminator group and 68 seconds (interquartile range: 40-159) in the control group (P = 0.54), and hazard ratio was 1.12 (95% CI, 0.73-1.71). The VascuLuminator has limited value in improving success at first attempt of facilitating IV cannulation in children with dark skin color.

  18. Cluster consensus in discrete-time networks of multiagents with inter-cluster nonidentical inputs.

    Science.gov (United States)

    Han, Yujuan; Lu, Wenlian; Chen, Tianping

    2013-04-01

    In this paper, cluster consensus of multiagent systems is studied via inter-cluster nonidentical inputs. Here, we consider general graph topologies, which might be time-varying. The cluster consensus is defined by two aspects: intracluster synchronization, the state at which differences between each pair of agents in the same cluster converge to zero, and inter-cluster separation, the state at which agents in different clusters are separated. For intra-cluster synchronization, the concepts and theories of consensus, including the spanning trees, scramblingness, infinite stochastic matrix product, and Hajnal inequality, are extended. As a result, it is proved that if the graph has cluster spanning trees and all vertices self-linked, then the static linear system can realize intra-cluster synchronization. For the time-varying coupling cases, it is proved that if there exists T > 0 such that the union graph across any T-length time interval has cluster spanning trees and all graphs has all vertices self-linked, then the time-varying linear system can also realize intra-cluster synchronization. Under the assumption of common inter-cluster influence, a sort of inter-cluster nonidentical inputs are utilized to realize inter-cluster separation, such that each agent in the same cluster receives the same inputs and agents in different clusters have different inputs. In addition, the boundedness of the infinite sum of the inputs can guarantee the boundedness of the trajectory. As an application, we employ a modified non-Bayesian social learning model to illustrate the effectiveness of our results.

  19. Proteus mirabilis fimbriae- and urease-dependent clusters assemble in an extracellular niche to initiate bladder stone formation.

    Science.gov (United States)

    Schaffer, Jessica N; Norsworthy, Allison N; Sun, Tung-Tien; Pearson, Melanie M

    2016-04-19

    The catheter-associated uropathogenProteus mirabilisfrequently causes urinary stones, but little has been known about the initial stages of bladder colonization and stone formation. We found thatP. mirabilisrapidly invades the bladder urothelium, but generally fails to establish an intracellular niche. Instead, it forms extracellular clusters in the bladder lumen, which form foci of mineral deposition consistent with development of urinary stones. These clusters elicit a robust neutrophil response, and we present evidence of neutrophil extracellular trap generation during experimental urinary tract infection. We identified two virulence factors required for cluster development: urease, which is required for urolithiasis, and mannose-resistantProteus-like fimbriae. The extracellular cluster formation byP. mirabilisstands in direct contrast to uropathogenicEscherichia coli, which readily formed intracellular bacterial communities but not luminal clusters or urinary stones. We propose that extracellular clusters are a key mechanism ofP. mirabilissurvival and virulence in the bladder.

  20. ULTRA-COMPACT DWARFS IN THE CORE OF THE COMA CLUSTER

    International Nuclear Information System (INIS)

    Madrid, Juan P.; Graham, Alister W.; Forbes, Duncan A.; Spitler, Lee R.; Harris, William E.; Goudfrooij, Paul; Ferguson, Henry C.; Carter, David; Blakeslee, John P.

    2010-01-01

    We have discovered both a red and a blue subpopulation of ultra-compact dwarf (UCD) galaxy candidates in the Coma galaxy cluster. We analyzed deep F475W (Sloan g) and F814W (I) Hubble Space Telescope images obtained with the Advanced Camera for Surveys Wide Field Channel as part of the Coma Cluster Treasury Survey and have fitted the light profiles of ∼5000 point-like sources in the vicinity of NGC 4874, one of the two central dominant galaxies of the Coma Cluster. Although almost all of these sources are globular clusters that remain unresolved, we found that 52 objects have effective radii between ∼10 and 66 pc, in the range spanned by dwarf globular transition objects (DGTOs) and UCDs. Of these 52 compact objects, 25 are brighter than M V ∼ -11 mag, a magnitude conventionally thought to separate UCDs and globular clusters. The UCD/DGTO candidates have the same color and luminosity distribution as the most luminous globular clusters within the red and blue subpopulations of the immensely rich NGC 4874 globular cluster system. Unlike standard globular clusters, blue and red UCD/DGTO subpopulations have the same median effective radius. The spatial distribution of UCD/DGTO candidates reveals that they congregate toward NGC 4874 and are not uniformly distributed. We find a relative deficit of UCD/DGTOs compared with globular clusters in the inner 15 kpc around NGC 4874; however, at larger radii UCD/DGTO and globular clusters follow the same spatial distribution.