54 research outputs found
Chronos vs. Kairos, quand les temps de l'organisation s'affrontent au lieu de se compléter : risques et paradoxes temporels du changement organisationnel
International audienceIn the organization theories, the concept of time is often used as an implicit framework to estimate the concept of movement or change. However, in many disciplines, in natural sciences as in social sciences, to understand further the complexity of causalities studied, time became an explicit concept. To underline the interest of a similar approach in organization theories, we propose the case of study of a company which meets some deep organizational dysfunctions following an effort of rationalization of its activities. The discussion of the results enables us to propose that a unique perception of time in organization (Chronos) is able to limit the understanding of an organizational complexity to the point to elude one of the principal components of its balance (Kairos).Dans l'ensemble des thĂ©ories des organisations, le concept du temps est souvent abordĂ© comme simple cadre implicite de l'action permettant seulement d'apprĂ©cier par sa variation la notion de mouvement ou de changement. Or, dans nombre de disciplines, aussi bien en sciences exactes qu'en sciences humaines, afin de rendre plus intelligible la complexitĂ© des causalitĂ©s observĂ©es, le temps s'est progressivement dĂ©parti de ce rĂŽle d'implicite pour devenir un concept plurivoque. Pour souligner l'intĂ©rĂȘt d'une approche analogue en thĂ©ories des organisations, nous proposerons le cas d'Ă©tude d'une entreprise confrontĂ©e, suite Ă un effort de rationalisation de ses activitĂ©s, Ă de profonds dysfonctionnements. La discussion des rĂ©sultats obtenus nous permettra de proposer qu'une perception strictement monologique du temps (Chronos) est en mesure de limiter le degrĂ© de comprĂ©hension d'une complexitĂ© organisationnelle au point d'Ă©luder une des composantes principales de son Ă©quilibre (Kairos) menaçant par la mĂȘme les efforts pourtant consentis pour en optimiser les activitĂ©s
Time as a determinant of the organizational change, a structurationist approach for a case study
In all the theories pertaining to organizations, the concept of time, also termed temporality, is often approached as a simple implicit framework of action. The notion of movement or change can only therefore be appreciated by its variation and rarely as an intrinsic dimension able to influence and provide greater insight into the complexities surrounding the causalities observed. Bearing this in mind, we have primed the theory of structuration, which considers time in addition to space, as a dimension of the structural dynamics. According to Giddens, each structure comprises a homeostatic principle, which tends to maintain its own living conditions over a given period despite the external pressures to which it can be submitted. Our interest here lies in the notion of disturbance resulting from this notion of homeostasis. What happens when a structural feature evolves? Can one see a disturbance? Can time be considered as a structural feature? In order to attempt to address these questions we will present a case study in which four operational offices of a large firm have the particularity of being faced with a spate of large scale organizational changes and a serious rise in psychosocial disorders. Without jeopardizing the possible causality link connecting both phenomena, we hypothesize that temporal dissonance could be considered as a source of explanation for this disturbance
Semi-Exclusive Processes: New Probes of Hadron Structure
We define and study hard ``semi-exclusive'' processes of the form which are characterized by a large momentum transfer between the particles
and and a large rapidity gap between the final state particle and
the inclusive system . Such reactions are in effect generalizations of deep
inelastic lepton scattering, providing novel currents which probe specific
quark distributions of the target at fixed momentum fraction. We give
explicit expressions for photo- and leptoproduction cross sections such as
in terms of parton distributions in the proton and the
pion distribution amplitude. Semi-exclusive processes provide opportunities to
study fundamental issues in QCD, including odderon exchange and color
transparency, and suggest new ways to measure spin-dependent parton
distributions.Comment: RevTex, 6 page
Lifetime of quasiparticles in hot QED plasmas
The calculation of the lifetime of quasiparticles in a QED plasma at high
temperature remains plagued with infrared divergences, even after one has taken
into account the screening corrections. The physical processes responsible for
these divergences are the collisions involving the exchange of very soft,
unscreened, magnetic photons, whose contribution is enhanced by the thermal
Bose-Einstein occupation factor. The self energy diagrams which diverge in
perturbation theory contain no internal fermion loops, but an arbitrary number
of internal magnetostatic photon lines. By generalizing the Bloch-Nordsieck
model at finite temperature, we can resum all the singular contributions of
such diagrams, and obtain the correct long time behaviour of the retarded
fermion propagator in the hot QED plasma: , where is the plasma frequency and
.Comment: 13 pages, LaTe
Structure Functions are not Parton Probabilities
The common view that structure functions measured in deep inelastic lepton
scattering are determined by the probability of finding quarks and gluons in
the target is not correct in gauge theory. We show that gluon exchange between
the fast, outgoing partons and target spectators, which is usually assumed to
be an irrelevant gauge artifact, affects the leading twist structure functions
in a profound way. This observation removes the apparent contradiction between
the projectile (eikonal) and target (parton model) views of diffractive and
small x_{Bjorken} phenomena. The diffractive scattering of the fast outgoing
quarks on spectators in the target causes shadowing in the DIS cross section.
Thus the depletion of the nuclear structure functions is not intrinsic to the
wave function of the nucleus, but is a coherent effect arising from the
destructive interference of diffractive channels induced by final state
interactions. This is consistent with the Glauber-Gribov interpretation of
shadowing as a rescattering effect.Comment: 35 pages, 8 figures. Discussion of physical consequences of final
state interactions amplified. Material on light-cone gauge choices adde
Hoverspill: a new amphibious vehicle for responding in difficult-to-access sites
Oil spill experience often shows that response activities are hampered due to the
absence of operative autonomous support capable of reaching particular sites or operate in
safe and efficient conditions in areas such as saltmarshes, mudflats, river banks, cliff
bottoms⊠This is the purpose of the so-called FP7 Hoverspill project (www.hoverspill.eu), a
3-year European project that recently reached completion: to design and build a small-size
amphibious vehicle designed to ensure rapid oil spill response. The result is an air-cushion
vehicle (ACV), known as Hoverspill, based on the innovative MACP (Multipurpose Air
Cushion Platform) developed by Hovertech and SOA. It is a completely amphibious vehicle
capable of working on land and on water, usable as a pontoon in floating conditions. Its
compactness makes it easy to transport by road. The project also included the design and
building of a highly effective integrated O/W Turbylec separator developed by YLEC. Spill
response equipment will be loaded on-board based on a modular concept enabling the vehicle
to carry out specific tasks with just the required equipmen
Lifetimes of quasiparticles and collective excitations in hot QED plasmas
The perturbative calculation of the lifetime of fermion excitations in a QED
plasma at high temperature is plagued with infrared divergences which are not
eliminated by the screening corrections. The physical processes responsible for
these divergences are the collisions involving the exchange of longwavelength,
quasistatic, magnetic photons, which are not screened by plasma effects. The
leading divergences can be resummed in a non-perturbative treatement based on a
generalization of the Bloch-Nordsieck model at finite temperature. The
resulting expression of the fermion propagator is free of infrared problems,
and exhibits a {\it non-exponential} damping at large times: , where is the plasma
frequency and .Comment: LaTex file, 57 pages, 11 eps figures include
Psi' to J/Psi Ratio in Diffractive Photoproduction
We evaluate the Psi' to J/Psi ratio in diffractive photoproduction in a
light-cone framework, using charmonium wave functions extracted from
non-relativistic potential models. Contrary to current belief, we find that the
best estimate for the ratio is a factor 2 to 5 below the data. The measured
ratio constrains the distribution of the charm quark-antiquark component of the
charmonium light-cone wave function and indicates that it is more compact than
in potential models. We predict that the inelastic photoproduction ratio will
be bigger than the elastic one, and will equal that measured in
hadroproduction.Comment: 4 pages, revte
Non-perturbative aspects of screening phenomena in abelian and non abelian gauge theories
When computed to one-loop order in resummed perturbation theory, the
non-abelian Debye mass appears to be logarithmically sensitive to the magnetic
scale . More generally, we show that in higher orders power-like infrared
divergences forbid the use of perturbation theory to calculate the corrections
to Debye screening. A similar infrared problem occurs in the determination of
the mass-shell for the scalar propagator in 2+1-dimensional scalar
electrodynamics. In this context, we provide a non-perturbative approach which
solves the infrared problems and allows for an accurate calculation of the
scalar propagator in the vicinity of the mass-shell.Comment: 29 pages, LaTex, 7 figures (not included, available upon request
Rescattering Effects in Quarkonium Production
We study eta_c and J/psi hadroproduction induced by multiple scattering off
fixed centres in the target. We determine the minimum number of hard
scatterings required and show that additional soft scatterings may be
factorized, at the level of the production amplitude for the eta_c and of the
cross section for the J/psi. The J/psi provides an interesting example of soft
rescattering effects occurring inside a hard vertex. We also explain the
qualitative difference between the transverse momentum broadening of the J/psi
and of the Upsilon observed in collisions on nuclei. We point out that
rescattering from spectators produced by beam and target parton evolution may
have important effects in J/psi production.Comment: 30 pages, Late
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