673 research outputs found
The effect of leader emotional intelligence on leader-follower chemistry: A study of construction project managers
Extending Nicolini’s (2002) notion of project ‘chemistry’, this paper proposes the development of a ‘leader-follower chemistry’ model associated with the quality of dyadic interpersonal communication in construction projects. The paper focuses on the project manager as leader and attempts to deepen understanding of the effect of a project manager’s Emotional Intelligence (EI) on the quality of interpersonal communication with their followers- being other members of the project team. While a project manager’s EI, with its associated emotional competencies, is often seen as critical in achieving good relationships with members of the project team, it remains a largely understudied concept, particularly in construction projects. Primary data collected using a series of analytical surveys and live observations of site-based projects meetings were used to examine the relationship between a project manager’s emotional competencies, particularly sensitivity and expressiveness, and leader-follower chemistry. Overall, 68 construction professionals participated in the study. The findings suggest that a project manager’s emotional sensitivity and expressiveness (particularly head gestures) may explain variance in the quality of leader-follower chemistry. Based on the empirical evidence in the context of team communication, a leader-follower chemistry model is introduced, which emphasises the importance of leaders’ emotional sensitivity and expressiveness in a leader-follower communication dyad. The model may be particularly salient in complex project networks with a large number of prominent actors
Application of a Self-Similar Pressure Profile to Sunyaev-Zel'dovich Effect Data from Galaxy Clusters
We investigate the utility of a new, self-similar pressure profile for
fitting Sunyaev-Zel'dovich (SZ) effect observations of galaxy clusters. Current
SZ imaging instruments - such as the Sunyaev-Zel'dovich Array (SZA) - are
capable of probing clusters over a large range in physical scale. A model is
therefore required that can accurately describe a cluster's pressure profile
over a broad range of radii, from the core of the cluster out to a significant
fraction of the virial radius. In the analysis presented here, we fit a radial
pressure profile derived from simulations and detailed X-ray analysis of
relaxed clusters to SZA observations of three clusters with exceptionally high
quality X-ray data: A1835, A1914, and CL J1226.9+3332. From the joint analysis
of the SZ and X-ray data, we derive physical properties such as gas mass, total
mass, gas fraction and the intrinsic, integrated Compton y-parameter. We find
that parameters derived from the joint fit to the SZ and X-ray data agree well
with a detailed, independent X-ray-only analysis of the same clusters. In
particular, we find that, when combined with X-ray imaging data, this new
pressure profile yields an independent electron radial temperature profile that
is in good agreement with spectroscopic X-ray measurements.Comment: 28 pages, 6 figures, accepted by ApJ for publication (probably April
2009
From (p)reheating to nucleosynthesis
This article gives a brief qualitative description of the possible evolution
of the early Universe between the end of an inflationary epoch and the end of
Big Bang nucleosynthesis. After a general introduction, establishing the
minimum requirements cosmologists impose on this cosmic evolutionary phase,
namely, successful baryogenesis, the production of cosmic dark matter, and
successful light-element nucleosynthesis, a more detailed discussion on some
recent developments follows. This latter includes the physics of preheating,
the putative production of (alternative) dark matter, and the current status of
Big Bang nucleosynthesis.Comment: 18 pages, 6 figures, to be published in "Classical and Quantum
Gravity", article based on a talk presented at ``The Early Universe and
Cosmological Observations: a Critical Review'', Cape Town, July 200
Doing audio-visual montage to explore time and space: The everyday rhythms of Billingsgate Fish Market
This article documents, shows and analyses the everyday rhythms of Billingsgate, London’s wholesale fish market. It takes the form of a short film based an audio-visual montage of time-lapse photography and sound recordings, and a textual account of the dimensions of market life revealed by this montage. Inspired by Henri Lefebvre’s Rhythmanalysis, and the embodied experience of moving through and sensing the market, the film renders the elusive quality of the market and the work that takes place within it to make it happen. The composite of audio-visual recordings immerses viewers in the space and atmosphere of the market and allows us to perceive and analyse rhythms, patterns, flows, interactions, temporalities and interconnections of market work, themes that this article discusses. The film is thereby both a means of showing market life and an analytic tool for making sense of it. This article critically considers the documentation, evocation and analysis of time and space in this way
Late time cosmic acceleration from vacuum Brans-Dicke theory in 5D
We show that the scalar-vacuum Brans-Dicke equations in 5D are equivalent to
Brans-Dicke theory in 4D with a self interacting potential and an effective
matter field. The cosmological implication, in the context of FRW models, is
that the observed accelerated expansion of the universe comes naturally from
the condition that the scalar field is not a ghost, i.e., . We
find an effective matter-dominated 4D universe which shows accelerated
expansion if . We study the question of whether
accelerated expansion can be made compatible with large values of ,
within the framework of a 5D scalar-vacuum Brans-Dicke theory with variable,
instead of constant, parameter . In this framework, and based on a
general class of solutions of the field equations, we demonstrate that
accelerated expansion is incompatible with large values of .Comment: In V2 the summary section is expanded. To be published in Classical
and Quantum Gravity
Fluid Interpretation of Cardassian Expansion
A fluid interpretation of Cardassian expansion is developed. Here, the
Friedmann equation takes the form where contains
only matter and radiation (no vacuum). The function g(\rhom) returns to the
usual 8\pi\rhom/(3 m_{pl}^2) during the early history of the universe, but
takes a different form that drives an accelerated expansion after a redshift . One possible interpretation of this function (and of the right hand
side of Einstein's equations) is that it describes a fluid with total energy
density \rho_{tot} = {3 m_{pl}^2 \over 8 \pi} g(\rhom) = \rhom + \rho_K
containing not only matter density (mass times number density) but also
interaction terms . These interaction terms give rise to an effective
negative pressure which drives cosmological acceleration. These interactions
may be due to interacting dark matter, e.g. with a fifth force between
particles . Such interactions may be intrinsically four
dimensional or may result from higher dimensional physics. A fully relativistic
fluid model is developed here, with conservation of energy, momentum, and
particle number. A modified Poisson's equation is derived. A study of
fluctuations in the early universe is presented, although a fully relativistic
treatment of the perturbations including gauge choice is as yet incomplete.Comment: 25 pages, 1 figure. Replaced with published version. Title changed in
journa
Self-Organizing Networks in Complex Infrastructure Projects
While significant importance is given to establishing formal organizational and contractual hierarchies, existing project management techniques neglect the management of self-organizing networks in large-infrastructure projects. We offer a case-specific illustration of self-organization using network theory as an investigative lens. The findings have shown that these networks exhibit a high degree of sparseness, short path lengths, and clustering in dense “functional” communities around highly connected actors, thus demonstrating the small-world topology observed in diverse real-world self-organized networks. The study underlines the need for these non-contractual functions and roles to be identified and sponsored, allowing the self-organizing network the space and capacity to evolve
Probing the last scattering surface through the recent and future CMB observations
We have constrained the extended (delayed and accelerated) models of hydrogen
recombination, by investigating associated changes of the position and the
width of the last scattering surface. Using the recent CMB and SDSS data, we
find that the recent data constraints favor the accelerated recombination
model, though the other models (standard, delayed recombination) are not ruled
out at 1- confidence level. If the accelerated recombination had
actually occurred in our early Universe, baryonic clustering on small-scales is
likely to be the cause of it. By comparing the ionization history of baryonic
cloud models with that of the best-fit accelerated recombination model, we find
that some portion of our early Universe has baryonic underdensity. We have made
the forecast on the PLANCK data constraint, which shows that we will be able to
rule out the standard or delayed recombination models, if the recombination in
our early Universe had proceeded with or lower, and
residual foregrounds and systematic effects are negligible.Comment: v2: matched with the accepted version (conclusions unchanged
On the origin of the large scale structures of the universe
We revise the statistical properties of the primordial cosmological density
anisotropies that, at the time of matter radiation equality, seeded the
gravitational development of large scale structures in the, otherwise,
homogeneous and isotropic Friedmann-Robertson-Walker flat universe. Our
analysis shows that random fluctuations of the density field at the same
instant of equality and with comoving wavelength shorter than the causal
horizon at that time can naturally account, when globally constrained to
conserve the total mass (energy) of the system, for the observed scale
invariance of the anisotropies over cosmologically large comoving volumes.
Statistical systems with similar features are generically known as glass-like
or lattice-like. Obviously, these conclusions conflict with the widely accepted
understanding of the primordial structures reported in the literature, which
requires an epoch of inflationary cosmology to precede the standard expansion
of the universe. The origin of the conflict must be found in the widespread,
but unjustified, claim that scale invariant mass (energy) anisotropies at the
instant of equality over comoving volumes of cosmological size, larger than the
causal horizon at the time, must be generated by fluctuations in the density
field with comparably large comoving wavelength.Comment: New section added; final version to appear in Physical Review D;
discussion extended and detailed with new calculations to support the claims
of the paper; statistical properties of vacuum fluctuations now discussed in
the context of FRW flat universe; new important conclussions adde
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