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 théories des organisations, le concept du temps est souvent abordé comme simple cadre implicite de l'action permettant seulement d'apprécier 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 complexité des causalités observées, le temps s'est progressivement départi de ce rôle d'implicite pour devenir un concept plurivoque. Pour souligner l'intérêt d'une approche analogue en théories des organisations, nous proposerons le cas d'étude d'une entreprise confrontée, suite à un effort de rationalisation de ses activités, à de profonds dysfonctionnements. La discussion des résultats obtenus nous permettra de proposer qu'une perception strictement monologique du temps (Chronos) est en mesure de limiter le degré de compréhension d'une complexité organisationnelle au point d'éluder une des composantes principales de son équilibre (Kairos) menaçant par la même les efforts pourtant consentis pour en optimiser les activités

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 $A+B \to C + Y$ which are characterized by a large momentum transfer between the particles $A$ and $C$ and a large rapidity gap between the final state particle $C$ and the inclusive system $Y$. Such reactions are in effect generalizations of deep inelastic lepton scattering, providing novel currents which probe specific quark distributions of the target $B$ at fixed momentum fraction. We give explicit expressions for photo- and leptoproduction cross sections such as $\gamma p \to \pi Y$ 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: $S_R(t)\sim \exp\{-\alpha T \, t\, \ln\omega_pt\}$, where $\omega_p=eT/3$ is the plasma frequency and $\alpha=e^2/4\pi$.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: $S_R(t)\sim \exp\{-\alpha T t \ln\omega_pt\}$, where $\omega_p=eT/3$ is the plasma frequency and $\alpha=e^2/4\pi$.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 $g^2T$. 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