677 research outputs found
Azimuth Quadrupole Systematics in Au-Au Collisions
We have measured -dependent two-particle number correlations on azimuth
and pseudorapidity for eleven centralities of and 200~GeV
Au-Au collisions at STAR. 2D fits to these angular correlations isolate the
azimuth quadrupole amplitude, denoted , from
localized same-side correlations. Event-plane measurements within
the STAR TPC acceptance can be expressed as a sum of the azimuth quadrupole and
the quadrupole component of the same-side peak. can be
transformed to reveal quadrupole spectra which are approximately
described by a fixed transverse boost and universal L\'evy form nearly
independent of centrality. A parametrization of can be
factored into centrality and -dependent pieces with a simple
dependence above 0.75 GeV/c. Results from STAR are compared to published data
and model predictions.Comment: Conference proceedings for Hot Quarks 201
PREDICTORS IN FINISHING POSITION OF NCAA DIVISION II SCHOOLS IN THE LEARFIELD SPORTS-NACDA DIRECTORS’ CUP: CULTURE TYPE AS A POTENTIAL MEDIATOR
Predictor variables, institution type and annual allocated revenue, were investigated as potential predictors of success in NCAA Division II Athletic Departments, on the outcome variable (points scored in the Learfield sports-NACDA Directors’ Cup), working through mediating variables representing culture type (clan, adhocracy, market, and hierarchy). Data were collected through an electronic survey emailed to all NCAA Division II institution athletic directors and head coaches. Data specific to institution type (public vs private) and the number of points an athletic department earned in the Learfield sports-NACDA Directors’ Cup was also collected from archived records. Statistical testing included the use of SPSS and the PROCESS Macro to make inferences about direct effects of predictor variables on the outcome variable, inferences about specific indirect effects of predictor variables on the outcome variable through mediating variables, pairwise comparisons between specific indirect effects, and inference about the total indirect effect.
Of all the respondents (N=847) to the survey, 285 different NCAA Division II athletic departments were represented. Because of the definition and nature of culture, the number of usable athletic departments was reduced to 67 with a total of 337 respondents with usable data for analysis. Bivariate correlation analysis between the number of Directors’ Cup points scored three culture types was found to be statistically significant. However, only the correlation between market culture the number of Directors’ Cup points scored was found to moderate in size r(335) = .250. Mediation analysis found only one statistically significant interaction between a dependent variable and mediating variable leading to the outcome. Annual allocated revenue was found to effect the number of Directors’ Cup points earned when operating through market culture. In addition, the mediating effect of market culture was found to be statistically different from adhocracy culture and hierarchy culture
The Impact of Language Translation on the Internal Structure of a Rating Scale: The Strengths and Difficulties Questionnaire in Spanish
The purpose of this study was to compare the psychometric properties of the Spanish version of the Strengths and Difficulties Questionnaire SDQ a 25-item behavioral screener with the English version Participants included in this study were 363 English-speaking parents and 334 Spanish-speaking parents of preschool age children ages 3-5 who took part in the Children s Hospital of Orange County University of California Irvine Initiative for the Development of Attention and Readiness CUIDAR program from 2004-2008 This study used data from the CUIDAR program to explore mean rating differences between the English and Spanish versions of the SDQ along with coefficient alpha as an indicator of reliability at the scale and composite level and factor analytic evidence of score validity Mean ratings of the scales and the Total Difficulties scale were very similar across language forms Reliability coefficients indicated alphas were higher for scores derived from the English forms compared to the Spanish forms at the scale and composite levels although neither form produced scores with adequate reliability at the scale level Finally the Five First Order Factor Model was the best-fitting and most valid representation of all 25 items of the SDQ regardless of the language of the for
The azimuth structure of nuclear collisions -- I
We describe azimuth structure commonly associated with elliptic and directed
flow in the context of 2D angular autocorrelations for the purpose of precise
separation of so-called nonflow (mainly minijets) from flow. We extend the
Fourier-transform description of azimuth structure to include power spectra and
autocorrelations related by the Wiener-Khintchine theorem. We analyze several
examples of conventional flow analysis in that context and question the
relevance of reaction plane estimation to flow analysis. We introduce the 2D
angular autocorrelation with examples from data analysis and describe a
simulation exercise which demonstrates precise separation of flow and nonflow
using the 2D autocorrelation method. We show that an alternative correlation
measure based on Pearson's normalized covariance provides a more intuitive
measure of azimuth structure.Comment: 27 pages, 12 figure
Life and Liesegang: Outcrop-Scale Microbially Induced Diagenetic Structures and Geochemical Self-Organization Phenomena Produced by Oxidation of Reduced Iron
The Kanab Wonderstone is sandstone (Shinarump Member, Chinle Formation) that is cemented and stained with iron oxide. The iron-oxide cementation and staining in these rocks have been considered examples of the Liesegang phenomenon, but we will show that they comprise a microbially induced structure. The spacing of bands of iron-oxide stain follow the Jablczynski spacing law (wherein the spacing between bands of iron-oxide stain increases as one traverses a series of bands) characteristic of Liesegang. Bands of iron-oxide cement exhibit more variable spacing and exhibit a weak but significant correlation between band thickness and distance between bands of cement. The pore-filling cement contains morphotypes that are similar in size and habit to those exhibited by microaerophilic iron-oxidizing bacteria. Other disseminated iron-oxide mineralization occurs as rhombohedra interpreted to be pseudomorphs after siderite. We interpret the cement to be produced by microbially mediated oxidation of siderite (a typical early diagenetic mineral in fluvial sandstones). Iron-oxidizing bacteria colonized the redox interface between siderite-cemented sand and porous sandstone. Microbes oxidized aqueous Fe(II), generating acid that caused siderite dissolution. The iron-oxide cement is the microbial product of a geochemical drive for organization; whereas the iron-oxide stain is true Liesegang. Together, they comprise a distinctive microbially induced structure with high preservation potential. Key Words: Biosignatures—Iron oxides—Diagenesis—Iron-oxidizing bacteria—Shinarump
Third Harmonic Flow of Charged Particles in Au+Au Collisions at GeV
In this proceedings, we report measurements of the third harmonic coefficient
of the azimuthal anisotropy, , known as triangular flow. The analysis is
for charged particles near midrapidity in Au+Au collisions at
= 200 GeV, based on data from the STAR experiment at the Relativistic Heavy Ion
Collider. Triangular flow as a function of centrality, pseudorapidity and
transverse momentum are reported using various methods, including a study of
the signal for particle pairs as a function of their pseudorapidity separation.
Results are compared with other experiments and model predictions.Comment: Talk given by Yadav Pandit (For the STAR Collaboration) at the 11th
International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio,
Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in
Journal of Physics: Conference Series (JPCS): 10 pages, 8 figure
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Robotic Motion Compensation for Beating Heart Intracardiac Surgery
3D ultrasound imaging has enabled minimally invasive, beating heart intracardiac procedures. However, rapid heart motion poses a serious challenge to the surgeon that is compounded by significant time delays and noise in 3D ultrasound. This paper investigates the concept of using a one-degree-of-freedom motion compensation system to synchronize with tissue motions that may be approximated by 1D motion models. We characterize the motion of the mitral valve annulus and show that it is well approximated by a 1D model. The subsequent development of a motion compensation instrument (MCI) is described, as well as an extended Kalman filter (EKF) that compensates for system delays. The benefits and robustness of motion compensation are tested in user trials under a series of non-ideal tracking conditions. Results indicate that the MCI provides an approximately 50% increase in dexterity and 50% decrease in force when compared with a solid tool, but is sensitive to time delays. We demonstrate that the use of the EKF for delay compensation restores performance, even in situations of high heart rate variability. The resulting system is tested in an in vitro 3D ultrasound-guided servoing task, yielding accurate tracking (1.15 mm root mean square) in the presence of noisy, time-delayed 3D ultrasound measurements.Engineering and Applied Science
3D macro- and microfabric analyses of Neoproterozoic diamictites from the Valjean Hills, California (United States)
The Cryogenian interval (720–635 Ma) is famous for a rich archive of diamictites, many of which were deposited during glaciations. Classic examples are exposed in the Kingston Peak Formation of the Valjean Hills, near Death Valley (United States), with previous work pointing to multiple glacial cycles in other outcrop belts. Within any glacial period, diamictites are widespread, and in addition, their mechanics of deposition are highly variable. Some are massive in appearance at outcrop or in hand specimens and apparently lack any information that allows their mode of emplacement to be elucidated. Yet, the correct interpretation for deep-time successions in this area is especially important, since it is debated whether the diamictites are either associated with a tectonically driven origin, associated with rifting at the south-western Laurentian margin alongside slope-controlled gravitational mass movement, or predominantly deposited as (sub)glacial diamictites. In this paper, we demonstrate how diamictite texture can be objectively quantified based on clast orientations, at both macroscale and microscale (micromorphology), guiding interpretations. Our method is based on a technique used for Quaternary sediments, by mapping the apparent longest axes of skeleton grains (ranging from fine-grained sand to fine-grained pebbles) in oriented thin sections and reconstructing their microfabric in a 3D space coupled with macrofabric data for each diamictite. In this way, we could identify a bimodal signal in the orientation of the longest axes for each sample. Evidence for shearing and soft sediment deformation supports either subaqueous or subglacial deposition with deformation induced by basal sliding with a paleoflow directed toward the southeast. Our combined approach of micro- and macrofabric analyses can also encourage acquiring accurate fabric data for seemingly structureless diamictites from other deep-time rock archives in an objective manner
New Perspectives on Glacial Geomorphology in Earth's Deep Time Record
International audienceThe deep time (pre-Quaternary) glacial record is an important means to understand the growth, development, and recession of the global cryosphere on very long timescales (10 6-10 8 Myr). Sedimentological description and interpretation of outcrops has traditionally played an important role. Whilst such data remain vital, new insights are now possible thanks to freely accessible aerial and satellite imagery, the widespread availability and affordability of Uncrewed Aerial Vehicles, and accessibility to 3D rendering software. In this paper, we showcase examples of glaciated landscapes from the Cryogenian, Ediacaran, Late Ordovician and Late Carboniferous where this approach is revolutionizing our understanding of deep time glaciation. Although some problems cannot be overcome (erosion or dissolution of the evidence), robust interpretations in terms of the evolving subglacial environment can be made. Citing examples from Australia (Cryogenian), China (Ediacaran), North and South Africa (Late Ordovician, Late Carboniferous), and Namibia (Late Carboniferous), we illustrate how the power of glacial geomorphology can be harnessed to interpret Earth's ancient glacial record
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