2,759 research outputs found
A typology for clients' multi-project environments
Construction management research and practice is dominated by a single project paradigm. This does not reflect the true nature of many construction clients who have large multi-project portfolios. Traditional single project management strategies are usually adopted for managing such portfolios - with limited success. The literature suggests that programmes, within portfolios, require different forms of management in order to optimize project delivery. In order to better understand these portfolios and thereby allow the exploration of new forms of management, a typology has been developed mapping out the various features of client's construction portfolios. The resultant typology provides a simple method for identifying the programme composition of a portfolio, highlighting the expected features of each programme type, and thereby directing management attention to the main aspects of each programme that can be optimized for efficiency. Six cases of client's construction project portfolios were studied using a highly structured, replication logic, case study methodology. A typology of clients' multi-project environments was developed and validated through literal and theoretical replication between cases. Three main types emerged as descriptive of programmes within client's construction portfolios: bounded programmes, target programmes and rolling programmes. The distinctive features of each type suggest that programme-specific approaches may be necessary for the successful delivery of projects within client's construction portfolios
Phase transition in the Higgs model of scalar dyons
In the present paper we investigate the phase transition
"Coulomb--confinement" in the Higgs model of abelian scalar dyons -- particles
having both, electric and magnetic , charges. It is shown that by dual
symmetry this theory is equivalent to scalar fields with the effective squared
electric charge e^{*2}=e^2+g^2. But the Dirac relation distinguishes the
electric and magnetic charges of dyons. The following phase transition
couplings are obtained in the one--loop approximation:
\alpha_{crit}=e^2_{crit}/4\pi\approx 0.19,
\tilde\alpha_{crit}=g^2_{crit}/4\pi\approx 1.29 and \alpha^*_{crit}\approx
1.48.Comment: 16 pages, 2 figure
Monopoles near the Planck Scale and Unification
Considering our (3+1)-dimensional space-time as, in some way, discrete or l
attice with a parameter , where is the Planck length,
we have investigated the additional contributions of lattice artifact monopoles
to beta-functions of the renormalisation group equations for the running fine
structure constants (i=1,2,3 correspond to the U(1), SU(2) and
SU(3) gauge groups of the Standard Model) in the Family Replicated Gauge Group
Model (FRGGM) which is an extension of the Standard Model at high energies. It
was shown that monopoles have times smaller magnetic charge in FRGGM
than in SM ( is the number of families in FRGGM). We have estimated al
so the enlargement of a number of fermions in FRGGM leading to the suppression
of the asymptotic freedom in the non-Abelian theory. We have shown that, in
contrast to the case of AntiGUT when the FRGGM undergoes the breakdown at
GeV, we have the possibility of unification if the
FRGGM-breakdown occurs at GeV. By numerical calculations we
obtained an example of the unification of all gauge interactions (including
gravity) at the scale GeV. We discussed the
possibility of or (SUSY or not SUSY) unifications.Comment: 49 pages, 7 figure
Clear Experimental Signature of Charge-Orbital density wave in NdCaMnO
Single Crystals of NdCaMnO have been prepared by the
travelling floating-zone method, and possible evidence of a charge -orbital
density wave in this material presented earlier [PRB68,092405 (2003)] using
High Resolution Electron Microscopy [HRTEM] and Electron Diffraction [ED]. In
the current note we present direct evidence of charge-orbital ordering in this
material using heat capacity measurements. Our heat capacity measurements
indicate a clear transition consistent with prior observation. We find two main
transitions, one at temperature K, and other at
K. In addition, we may also conclude that there is a strong electron-phonon
coupling in this material.Comment: 7 pages, 8 figure
Phase transition in gauge theories, monopoles and the Multiple Point Principle
This review is devoted to the Multiple Point Principle (MPP), according to
which several vacuum states with the same energy density exist in Nature. The
MPP is implemented to the Standard Model (SM), Family replicated gauge group
model (FRGGM) and phase transitions in gauge theories with/without monopoles.
Lattice gauge theories are reviewed. The lattice results for critical coupling
constants are compared with those of the Higgs Monopole Model (HMM), in which
the lattice artifact monopoles are replaced by the point-like Higgs scalar
particles with a magnetic charge. Considering our (3+1)-dimensional space-time
as discrete, for example, as a lattice with a parameter a=\lambda_P, equal to
the Planck length, we have investigated the additional contributions of
monopoles to beta-functions of renormalization group equations in the FRGGM
extended beyond the SM at high (the Planck scale) energies. We have reviewed
that, in contrast to the Anti-grand unified theory (AGUT), there exists a
possibility of unification of all gauge interactions (including gravity) near
the Planck scale due to monopoles. The unifications [SU(5)]^3 and [SO(10)]^3 at
the GUT-scale \sim 10^{18} GeV are briefly discussed.Comment: 100 pages, 25 figures, typos correcte
Search for Heavy Leptons at Hadron Colliders
Four models are considered which contain heavy leptons beyond the three
families of the standard model. Two are fourth-generation extensions of the
standard model in which the right-handed heavy leptons are either isosinglets
or in an isodoublet; the other two are motivated by the aspon model of CP
violation. In all these models, the heavy neutrino can either be heavier than,
or comparable in mass to, the charged lepton leading to the possibility that
the charged lepton is very long-lived. Production cross section and signatures
for the heavy leptons are computed for the SSC and LHC.Comment: 17 pages(8 figures are not included),TRI-PP-92-9
Vacuum Stability Higgs Mass Bound Revisited with Implications for Extra Dimension Theories
We take the standard model to be an effective theory including higher
dimensional operators suppressed by scale and re-examine the higgs
mass bounds from the requirements of vacuum stability. Our results show that
the effects of the higher dimensional operators on the higgs mass limits are
significant. As an implication of our results, we study the vacuum stability
higgs mass bounds in theories with extra dimensions.Comment: Latex, 14 pages, 1 figure. Added references. To appear in Phys. Rev.
Influence of Light-trap Catches on Sex Ratio of Insects and Infestation in the Field of Cucurbitaceae
Insects are the curse for any type of crop and stored grains. Many techniques have been used so far to combat them. Pesticides are a major part of these techniques, but they also have negative aspects. In many European countries, the alternative techniques are, in practice, on low scale which is eco-friendly. Light-trap is one of them, which is used to study the effects on cucurbit insect pests in the present stud
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