• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 269
  • 202
  • 138
  • 108
  • 54
  • 23
  • 19
  • 18
  • 16
  • 14
  • 9
  • 8
  • 8
  • 8
  • 7
  • Tagged with
  • 1002
  • 92
  • 90
  • 66
  • 65
  • 65
  • 64
  • 62
  • 62
  • 62
  • 62
  • 61
  • 59
  • 58
  • 57
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Social Media And Credibility Indicator: The Effects Of Bandwagon And Identity Cues Within Online Health And Risk Contexts

Lin, Xialing 01 January 2016 (has links)
Three studies were conducted to investigate how social media affordances influence individuals’ source credibility perceptions in risk situations. The MAIN model (Sundar, 2008), warranting theory (Walther & Parks, 2002), and signaling theory (Donath, 1999) served as the theoretical framework to examine the effects of bandwagon cues and identity cues embedded in retweets and users’ profile pages for health and risk online information processing. Study One examines whether bandwagon heuristics triggered by retweets would influence individuals’ source credibility judgments. Study Two investigates how bandwagon heuristics interact with different identity heuristics in credibility heuristics on an individual level. Study Three explores bandwagon heuristics at the organizational level. Three post-test only experiments with self-report online surveys were conducted to investigate the hypothesis and research questions. Results indicate that different online heuristic cues impact the judgments of competence, goodwill, and trustworthiness at different levels. Authority strongly influenced source credibility perceptions. A reverse-bandwagon effect was observed in influencing source credibility judgments. Theoretical and practical implications are discussed.
432

CONSTRAINING THE MOVEMENT OF THE SPIRAL FEATURES AND THE LOCATIONS OF PLANETARY BODIES WITHIN THE AB AUR SYSTEM

Lomax, Jamie R., Wisniewski, John P., Grady, Carol A., McElwain, Michael W., Hashimoto, Jun, Kudo, Tomoyuki, Kusakabe, Nobuhiko, Okamoto, Yoshiko K., Fukagawa, Misato, Abe, Lyu, Brandner, Wolfgang, Brandt, Timothy D., Carson, Joseph C., Currie, Thayne M, Egner, Sebastian, Feldt, Markus, Goto, Miwa, Guyon, Olivier, Hayano, Yutaka, Hayashi, Masahiko, Hayashi, Saeko S., Henning, Thomas, Hodapp, Klaus W., Inoue, Akio, Ishii, Miki, Iye, Masanori, Janson, Markus, Kandori, Ryo, Knapp, Gillian R., Kuzuhara, Masayuki, Kwon, Jungmi, Matsuo, Taro, Mayama, Satoshi, Miyama, Shoken, Momose, Munetake, Morino, Jun-Ichi, Moro-Martin, Amaya, Nishimura, Tetsuo, Pyo, Tae-Soo, Schneider, Glenn H, Serabyn, Eugene, Sitko, Michael L., Suenaga, Takuya, Suto, Hiroshi, Suzuki, Ryuji, Takahashi, Yasuhiro H., Takami, Michihiro, Takato, Naruhisa, Terada, Hiroshi, Thalmann, Christian, Tomono, Daigo, Turner, Edwin L., Watanabe, Makoto, Yamada, Toru, Takami, Hideki, Usuda, Tomonori, Tamura, Motohide 22 August 2016 (has links)
We present a new analysis of multi-epoch, H-band, scattered light images of the AB Aur system. We use a Monte Carlo radiative transfer code to simultaneously model the system's spectral energy distribution (SED) and H-band polarized intensity (PI) imagery. We find that a disk-dominated model, as opposed to one that is envelope-dominated, can plausibly reproduce AB Aur's SED and near-IR imagery. This is consistent with previous modeling attempts presented in the literature and supports the idea that at least a subset of AB Aur's spirals originate within the disk. In light of this, we also analyzed the movement of spiral structures in multi-epoch H-band total light and PI imagery of the disk. We detect no significant rotation or change in spatial location of the spiral structures in these data, which span a 5.8-year baseline. If such structures are caused by disk-planet interactions, the lack of observed rotation constrains the location of the orbit of planetary perturbers to be >47 au.
433

THE ERUPTION OF THE CANDIDATE YOUNG STAR ASASSN-15QI

Herczeg(沈雷歌), Gregory J., Dong, Subo, Shappee, Benjamin J., Chen(陈 平), Ping, Hillenbrand, Lynne A., Jose, Jessy, Kochanek, Christopher S., Prieto, Jose L., Stanek, K. Z., Kaplan, Kyle, Holoien, Thomas W.-S., Mairs, Steve, Johnstone, Doug, Gully-Santiago, Michael, Zhu, Zhaohuan, Smith, Martin C., Bersier, David, Mulders, Gijs D., Filippenko, Alexei V., Ayani, Kazuya, Brimacombe, Joseph, Brown, Jonathan S., Connelley, Michael, Harmanen, Jussi, Itoh, Ryosuke, Kawabata, Koji S., Maehara, Hiroyuki, Takata, Koji, Yuk, Heechan, Zheng, WeiKang 02 November 2016 (has links)
Outbursts on young stars are usually interpreted as accretion bursts caused by instabilities in the disk or the star-disk connection. However, some protostellar outbursts may not fit into this framework. In this paper, we analyze optical and near-infrared spectra and photometry to characterize the 2015 outburst of the probable young star ASASSN-15qi. The similar to 3.5mag brightening in the V band was sudden, with an unresolved rise time of less than one day. The outburst decayed exponentially by 1mag for 6. days and then gradually back to the pre-outburst level after 200 days. The outburst is dominated by emission from similar to 10,000K gas. An explosive release of energy accelerated matter from the star in all directions, seen in a spectacular cool, spherical wind with a maximum velocity of 1000 km s(-1). The wind and hot gas both disappeared as the outburst faded and the source returned to its quiescent F-star spectrum. Nebulosity near the star brightened with a delay of 10-20 days. Fluorescent excitation of H-2 is detected in emission from vibrational levels as high as v = 11, also with a possible time delay in flux increase. The mid-infrared spectral energy distribution does not indicate the presence of warm dust emission, though the optical photospheric absorption and CO overtone emission could be related to a gaseous disk. Archival photometry reveals a prior outburst in 1976. Although we speculate about possible causes for this outburst, none of the explanations are compelling.
434

RESOLVING THE PLANET-HOSTING INNER REGIONS OF THE LkCa 15 DISK

Thalmann, C., Janson, M., Garufi, A., Boccaletti, A., Quanz, S. P., Sissa, E., Gratton, R., Salter, G., Benisty, M., Bonnefoy, M., Chauvin, G., Daemgen, S., Desidera, S., Dominik, C., Engler, N., Feldt, M., Henning, T., Lagrange, A.-M., Langlois, M., Lannier, J., Coroller, H. Le, Ligi, R., Ménard, F., Mesa, D., Meyer, M. R., Mulders, G. D., Olofsson, J., Pinte, C., Schmid, H. M., Vigan, A., Zurlo, A. 08 September 2016 (has links)
LkCa 15 hosts a pre-transitional disk as well as at least one accreting protoplanet orbiting in its gap. Previous disk observations have focused mainly on the outer disk, which is cleared inward of similar to 50 au. The planet candidates, on the other hand, reside at orbital radii around 15 au, where disk observations have been unreliable until recently. Here, we present new J-band imaging polarimetry of LkCa 15 with SPHERE IRDIS, yielding the most accurate and detailed scattered-light images of the disk to date down to the planet-hosting inner regions. We find what appear to be persistent asymmetric structures in the scattering material at the location of the planet candidates, which could be responsible at least for parts of the signals measured with sparse-aperture masking. These images further allow us to trace the gap edge in scattered light at all position angles and search the inner and outer disks for morphological substructure. The outer disk appears smooth with slight azimuthal variations in polarized surface brightness, which may be due to shadowing from the inner disk or a two-peaked polarized phase function. We find that the near-side gap edge revealed by polarimetry matches the sharp crescent seen in previous ADI imaging very well. Finally, the ratio of polarized disk to stellar flux is more than six times larger in the J-band than in the RI bands.
435

Trendy ve vývoji zahraničních preprimárních a primárních škol / Progress in trends of foreign pre-primary and primary schools

Kellerová, Lucie January 2015 (has links)
This dissertation deals with new approaches of alternative schooling in foreign countries which recently became very popular. These three schools and approaches chosen for this dissertation are not known in Czech Republic yet. The dissertation presents these alternative schools and proposes alternative brushing up of the ideas to the maintain schools. The first school and the first approach of alternative is democratic school or also free school. The oldest democratic school is Summerhill in the east of England. The second interesting approach and school is Te Whāriki from New Zealand. The framework deals with education through socio-cultural context. The last representative of schooling which dissertation deals with will be Reggio Emillia, which is from Italy and based on ideas of Loris Malaguzzi. The dissertation applies to main philosophies of these three alternatives, which appears abroad and mainly in Great Britain. This piece of work evaluates similarities and differences of these alternative schools. According to from which country the concrete school comes from and circumstances influencing the origin. The dissertation should contribute to the extension to Czech awareness of more alternative schools that are developing in the world. Also the piece of work devotes to ideas which could be...
436

On unicity problems of meromorphic mappings of Cn into PN(C) and the ramification of the Gauss maps of complete minimal surfaces / Problèmes d'unicité pour des applications méromorphes de Cn dans CPN et ramification de l'application de Gauss pour des surfaces minimales complètes

Ha, Pham Hoang 03 May 2013 (has links)
En 1975 H. Fujimoto a généralisé les résultats d’unicité pour des fonctions holomorphes dus à Nevanlinna pour des applications méromorphes de Cn dans CPN. Il a démontré que pour deux applications méromorphes non linéairement dégénérées f et g de Cn dans CPN, si elles ont les mêmes images réciproques, comptées avec leurs multiplicités, par rapport à (3N + 2) hyperplans de CPN en position générale, alors f g. Depuis, ce problème a été étudié d’une manière intensive par H. Fujimoto, W. Stoll, L. Smiley, M. Ru, G. Dethloff-T.V.Tan, D.D.Thai-S.D.Quang, Chen-Yan et d’autres auteurs. En parallèle avec le développement de la théorie de Nevanlinna, la théorie de distribution des valeurs de l’application de Gauss des surfaces minimales dans Rm a été étudiée d’une manière intensive par R.Osserman, S.S. Chern, F. Xavier, H. Fujimoto, S.J. Kao, M. Ru et d’autres auteurs. Dans cette thèse, nous avons continué d’étudier ces problèmes. Nous avons obtenu les résultats principaux suivants: +) Théorèmes d’unicité avec multiplicités tronquées des applications méromorphes de Cn dans CPN ayant les mêmes images réciproques par rapport è (2N + 2) hyperplans de CPN. +) Théorèmes d’unicité avec multiplicités tronquées des applications méromorphes de Cn dans CPN ayant des cibles mobiles et un ensemble d’identité petit. +) Théorèmes d’unicité avec multiplicités tronquées des applications méromorphes de Cn dans CPN ayant des cibles fixes ou mobiles et satisfaisant des conditions sur les dérivées. +) Théorèmes de ramification de l’application de Gauss de certaines classes de surfaces minimales complètes dans Rm (m = 3,4). / In 1975, H. Fujimoto generalized Nevanlinna’s known results for meromorphic fonctions to the case of meromorphic mappings of Cn into PN(C). He proved that for two linearly nondegenerate meromorphic mappings f and g of C into PN(C). if they have the saine inverse images counted with multiplicities for 3N + 2 hyperplanes in general position in PN(C) then f = g. After that, this problem has been studied intensively by a number of mathematicans as H. Fujimoto, W. Stoll, L. Smiley, M. Ru, G. Dethloff - T. V. Tan, D. D. Thai - S. D. Quang, Chen-Yan and so on. Parallel to the development of Nevanlinna theory, the value distribution theory of the Gauss map of minimal surfaces immersed in Rm vas studied by many mathematicans as R. Osserman, S.S. Chern, F. Xavier, H. Fujimoto, S. J. Kao, M. Ru and many other mathematicans. In this thesis, we continuous studing some problems on these directions. The main goals of the thesis are followings. • Unicity theorems with truncated multiplicities of meromorphic mappings of Cn into PN(C) sharing 2N + 2 fixed hyperplanes.• Unicity theorems with truncated multiplicities of meromorphic mappings of Cn into PN(C) for moving targets, and a small set of identity.
437

Kolizní vývoj hlavního pásu asteroidů po dobu 4 miliard let / Collisional evolution of the Main Asteroid Belt over 4 billion years

Cibulková, Helena January 2013 (has links)
In this work, we constructed a new model for the collisional evolution of the Main Asteroid Belt. Our goals are to test the scaling law from the work of Benz & Asphaug (1999) and ascertain if it can be used for the whole belt. We want to find initial size-frequency distributions (SFDs) for the considered six parts of the belt, and to verify if the number of asteroid families created during the simulation matches the number of observed families as well. We used new observational data from the WISE satellite (Masiero et al., 2011) to construct the observed SFDs. We simulated mutual collisions of asteroids with a modified Boulder code (Morbidelli et al., 2009), in which the results of hydrodynamic (SPH) simulations from the work of Durda et al. (2007) are included. Because material characteris- tics can affect breakups, we created two models - for monolithic asteroids and for rubble-piles (Benavidez et al., 2012). The results for monolithic and rubble- -pile asteroids are comparable and in both cases the number of created families is, within uncertainties, consistent with the observations. A disagreement of the SFDs for a limited size range D 1 to 5 km a is a good motivation to conduct new SPH simulations with relatively small targets. 1
438

Process enhancement and database support for vehicle operational readiness reporting

Menko, Russell H. 12 1900 (has links)
Approved for public release, distribution is unlimited / The U.S. Army uses a Unit Readiness Index to track the combat readiness of systems. The Unit Readiness Index relies on the accuracy of automated and manual testing of the hardware and related software of the Line Replaceable Units (LRUs) that comprise the system. These tests are based on a GO/NOGO scenario. When an LRU fails, vehicle commanders, and commanders up the chain of command, can override the failure and continue with a mission. Overriding the NOGO recommendations produces a false combat readiness status for the unit, and creates a number of problems related to unit combat decisions as well as logistical support. This thesis introduces a new process for more effectively tracking combat readiness. It outlines some of the problems associated with the current GO/NOGO scenario and examines the current tests, artifacts and data available from the current process. It proposes an additional Report process and shows how this new process will eliminate the readiness tracking problems associated with the GO/NOGO scenario. It also presents the design of a Vehicle Database and Master Fault Database to support the proposed process, and presents several sample reports generated from this Master Fault Database. / Civilian, United States Army RDECOM - TARDEC
439

Main street revitalization effort for the village of Union, Nebraska

Cox, Taylor A. January 1900 (has links)
Master of Regional and Community Planning / Department of Landscape Architecture/Regional and Community Planning / Huston Gibson / Rural communities across America are working to strengthen their economies, provide better quality of life to residents, and build on assets such as traditional main streets, transportation initiatives, and natural amenities and resources. Today, rural communities face an array of challenges. Small communities are vulnerable to the impacts of expensive commutes, lack of mobility, financial resources, and other services. According to the USDA, “Some small communities, have limited local government staff, experience, or funding, which can mean few resources dedicated to providing sustainable amenities, regional collaboration, and other efforts to identify shared community goals and visions that can help shape growth and development” (USDA, 2011). Small communities must work hard to compete with larger cities and other communities to sustain economically and become prominent. This is often noticeable when there is a lack of investment and economic prosperity. Many rural communities have limited transportation options. Most small communities are not fit to support multiple modes of transportation, which limits access to jobs, medical care, and educational opportunities. For those who do drive, commutes to distant employment centers can be time consuming and require a large percentage of the family budget to be spent on transportation (USDA, 2011). In addition, intercity and regional mobility are drivers of economic growth in rural communities and bring tourists and other consumers to community businesses. Rural communities and small towns should be valued for their distinctive and historic features. Communities that conserve and build upon these resources, such as historic downtowns and main streets, will be better positioned to enhance quality of life for their residents. Without revitalizing main streets we would not see the places of shared memory where people are suppose to come together to live, work, and play.
440

The Upper Critical and Lower Main Zones of the eastern Bushveld Complex

Seabrook, Charlotte 15 November 2006 (has links)
Student Number : 0201438A - PhD thesis - School of Geosciences - Faculty of Science / This project focuses on the Upper Critical and Lower Main Zones in the eastern Bushveld Complex, South Africa. Lithological and stratigraphic information show that there are distinct differences at this level between the eastern and western limbs of the complex. Geochemical studies are centred on the Merensky and Bastard Cyclic Units in which the platiniferous Merensky Reef occurs. A major geochemical hiatus occurs in the Bushveld Complex at the level of the platiniferous Merensky Reef, close to the Critical/Main Zone boundary. The origin of this hiatus and its relation to mineralisation has not been fully resolved. Geochemical parameters are investigated that allow minerals in the Merensky and Bastard Cyclic Units to be classified as originating from either Critical or Main Zone magmas. Modelling of element ratios (Ni/Y, Cr/Ni, Cr/Co, Y/Co, Cr/V, Co/V and Cr/MgO) demonstrates the varying reliability of using ratios as geochemcial tools to constrain magma influxes within a chamber. However, it is shown that the Cr/MgO ratio is effective in determining real differences across the Critical/Main Zone boundary that are independent of lithology. In addition, initial Sr isotope ratios for plagioclase are significantly different in Critical and Main Zone rocks. Geochemical data through the Merensky and Bastard Cyclic Units indicate that orthopyroxene that originated from magma with composition like that of the Critical Zone magma sometimes occurs together with plagioclase that originated from Main Zone magma. In detail, in the pyroxenite at the base of the Merensky Unit, both plagioclase and orthopyroxene display Critical Zone signatures, but in the overlying part of the Merensky Cyclic Unit, plagioclase increasingly shows a Main Zone signature, whereas orthopyroxene continues to display a Critical Zone signature. Similarly, in the Bastard pyroxenite, Sr isotopes and absolute Sr in plagioclase display a range of values from Main Zone to Critical Zone, but orthopyroxene consistently displays Critical Zone affinity. These observations of mineral disequilibrium clearly show that the two major minerals in the Merensky and Bastard Cyclic Units were formed from two different, but coexisting, magmas. A model that accounts for this disequilibrium is proposed here. It invokes the influx of Main Zone magma at the level of the base of the Merensky unit that dispalced the Critical Zone magma upward, but the two magmas did not mix. The latter continued to crystallise orthopyroxene which sank through the Main Zone influx, due to its density contrast. These crystals collected on the crystal pile to form the Merensky pyroxenite. The Main Zone magma, into which the cumulus Critical Zone orthopyroxene accumulated, crystallised interstitial plagioclase that had a Main Zone Sr isotopic ratio. Whole-rock, major element geochemical data show that a variable proportion of the plagioclase in both the Merensky and Bastard pyroxenites is cumulus. It is inferred to have accumulated with orthopyroxene and has a Critical Zone initial Sr isotope ratio. Thus the two pyroxenites now yield a mixed Sr isotopic signature of Critical Zone cumulus and Main Zone intercumulus and possibly cumulus plagioclase that varies along strike. Above the two pyroxenites, the Sr signature of the norites and anorthosites of both cyclic units is dominated by cumulus plagioclase from the Main Zone magma. It is concluded that the variations in initial Sr isotope ratios do not result from mixing of magmas, but result from accumulation of orthopyroxene and plagioclase from a higher, isotopically distinct layer of magma into an underlying layer. The Merensky and Bastard Cyclic Units therefore display features of Critical or Main Zone magma characteristics depending upon which chemical parameter is considered. These cycles are therefore classified as a Transitional Unit.

Page generated in 0.0501 seconds