1,272 research outputs found
Subject preferences of fifth-grade children.
Thesis (Ed.M.)--Boston University
N.B.:Pages 155 and 309 are missing from original thesis
Condensate cosmology -- dark energy from dark matter
Imagine a scenario in which the dark energy forms via the condensation of
dark matter at some low redshift. The Compton wavelength therefore changes from
small to very large at the transition, unlike quintessence or metamorphosis. We
study CMB, large scale structure, supernova and radio galaxy constraints on
condensation by performing a 4 parameter likelihood analysis over the Hubble
constant and the three parameters associated with Q, the condensate field:
Omega_Q, w_f and z_t (energy density and equation of state today, and redshift
of transition). Condensation roughly interpolates between Lambda CDM (for large
z_t) and sCDM (low z_t) and provides a slightly better fit to the data than
Lambda CDM. We confirm that there is no degeneracy in the CMB between H and z_t
and discuss the implications of late-time transitions for the Lyman-alpha
forest. Finally we discuss the nonlinear phase of both condensation and
metamorphosis, which is much more interesting than in standard quintessence
models.Comment: 13 pages, 13 colour figures. Final version with discussion of TE
cross-correlation spectra for condensation and metamorphosis in light of the
WMAP result
Higher media multi-tasking activity is associated with smaller gray-matter density in the anterior cingulate cortex
Media multitasking, or the concurrent consumption of multiple media forms, is increasingly prevalent in today’s society and has been associated with negative psychosocial and cognitive impacts. Individuals who engage in heavier media-multitasking are found to perform worse on cognitive control tasks and exhibit more socio-emotional difficulties. However, the neural processes associated with media multi-tasking remain unexplored. The present study investigated relationships between media multitasking activity and brain structure. Research has demonstrated that brain structure can be altered upon prolonged exposure to novel environments and experience. Thus, we expected differential engagements in media multitasking to correlate with brain structure variability. This was confirmed via Voxel-Based Morphometry (VBM) analyses: Individuals with higher Media Multitasking Index (MMI) scores had smaller gray matter density in the anterior cingulate cortex (ACC). Functional connectivity between this ACC region and the precuneus was negatively associated with MMI. Our findings suggest a possible structural correlate for the observed decreased cognitive control performance and socio-emotional regulation in heavy media-multitaskers. While the cross-sectional nature of our study does not allow us to specify the direction of causality, our results brought to light novel associations between individual media multitasking behaviors and ACC structure differences
A research agenda for seed-trait functional ecology
Trait-based approaches have improved our understanding of plant evolution, community assembly and ecosystem functioning. A major challenge for the upcoming decades is to understand the functions and evolution of early life-history traits, across levels of organization and ecological strategies. Although a variety of seed traits are critical for dispersal, persistence, germination timing and seedling establishment, only seed mass has been considered systematically. Here we suggest broadening the range of morphological, physiological and biochemical seed traits to add new understanding on plant niches, population dynamics and community assembly. The diversity of seed traits and functions provides an important challenge that will require international collaboration in three areas of research. First, we present a conceptual framework for a seed ecological spectrum that builds upon current understanding of plant niches. We then lay the foundation for a seed-trait functional network, the establishment of which will underpin and facilitate trait-based inferences. Finally, we anticipate novel insights and challenges associated with incorporating diverse seed traits into predictive evolutionary ecology, community ecology and applied ecology. If the community invests in standardized seed-trait collection and the implementation of rigorous databases, major strides can be made at this exciting frontier of functional ecology
Применение информационных технологий в туризме: интерактивная информационная система-экскурсовод
Цель работы: проанализировать достаточный набор функций интерактивной программы-экскурсовода
и найти возможные методы ее реализации
Prospectus, September 23, 1974
ALL SET FOR STUGO ELECTION; Trustees Approve Budget For \u2774-\u2775, Partial Figures On Page 12; 16 Candidates On Ballot For 1st \u2774 Election; PC Counselors Offer More Than Counseling; Attention: Transfer Students; mercy for who?; The Short Circuit; The Kaleidoscope; Letters; Point-Counterpoint: How Do You View America\u27s Future?; Here Are Candidates\u27 Platforms; State House Candidates To Debate Here; Friends; Untitled; Lit. 1.: A Secret Something, Untitled, Rebirth, Everyone\u27s looking for...; \u27DIRT\u27 Comes Off Clean; Really Raunchy Record Review: Eric Clapton, 461 Ocean Boulevard; Meeting For Prospective Debators; Classified Ads; Books: All The President\u27s Men; Republicans To Have Coffee Wednesday; Phi Beta Lambda Meetings Scheduled; APO Chapter Formed Here; In The Dark: That\u27s Entertainment ; Jock Talk; Harriers Perform Well, Abbey Pleased; IM Football Starts Play On 25th; Howell First \u27Fast Freddy\u27; Bowling Bulletin Board; Watching A Counselor At Work; Registration Drive; Cross Country Schedule; Last Chance For Girls IM Football; Fast Freddy\u27s Football Forecast; Callboard; Parkland Events; Summary Of Approved Budget; Vets Elect Officers; A Column By And For Women; Fashion Forecasthttps://spark.parkland.edu/prospectus_1974/1009/thumbnail.jp
Precision Determination of the Neutron Spin Structure Function g1n
We report on a precision measurement of the neutron spin structure function
using deep inelastic scattering of polarized electrons by polarized
^3He. For the kinematic range 0.014<x<0.7 and 1 (GeV/c)^2< Q^2< 17 (GeV/c)^2,
we obtain at an average . We find relatively large negative
values for at low . The results call into question the usual Regge
theory method for extrapolating to x=0 to find the full neutron integral
, needed for testing quark-parton model and QCD sum rules.Comment: 5 pages, 3 figures To be published in Phys. Rev. Let
The Red Radio Ring: a gravitationally lensed hyperluminous infrared radio galaxy at z = 2.553 discovered through the citizen science project SPACE WARPS
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.We report the discovery of a gravitationally lensed hyperluminous infrared galaxy (intrinsic LIR ≈ 1013 L⊙) with strong radio emission (intrinsic L1.4 GHz ≈ 1025 W Hz−1) at z = 2.553. The source was identified in the citizen science project SPACE WARPS through the visual inspection of tens of thousands of iJKs colour composite images of luminous red galaxies (LRGs), groups and clusters of galaxies and quasars. Appearing as a partial Einstein ring (re ≈ 3 arcsec) around an LRG at z = 0.2, the galaxy is extremely bright in the sub-millimetre for a cosmological source, with the thermal dust emission approaching 1 Jy at peak. The redshift of the lensed galaxy is determined through the detection of the CO(3→2) molecular emission line with the Large Millimetre Telescope's Redshift Search Receiver and through [O III] and Hα line detections in the near-infrared from Subaru/Infrared Camera and Spectrograph. We have resolved the radio emission with high-resolution (300–400 mas) eMERLIN L-band and Very Large Array C-band imaging. These observations are used in combination with the near-infrared imaging to construct a lens model, which indicates a lensing magnification of μ ≈ 10. The source reconstruction appears to support a radio morphology comprised of a compact (<250 pc) core and more extended component, perhaps indicative of an active nucleus and jet or lobe.Peer reviewedFinal Published versio
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