Reframing Systems Disasters With Three Perspectives of organizational Culture

This paper presents the major literature on systems disasters and how organizational culture is portrayed in this literature. The paper then outlines the three cultural perspectives used by Martin 2002 to describe organizational cultures: integration, differentiation, and fragmentation. The paper explores show these perspectives influence interpretations about the disasters described. The paper concludes that the effect of an organization’s culture on safety, reliability, and disasters can be fully understood only when all three perspectives are applied

The Anisotropy in the Cosmic Microwave Background At Degree Angular Scales

We detect anisotropy in the cosmic microwave background (CMB) at degree angular scales and confirm a previous detection reported by Wollack et al. (1993). The root-mean-squared amplitude of the fluctuations is $44^{+13}_{-7} \mu$K. This may be expressed as the square root of the angular power spectrum in a band of multipoles between $l_{eff}=69^{+29}_{-22}$. We find $\delta T_l = \sqrt{l(2l+1)/4\pi} = 42^{+12}_{-7} \mu$K. The measured spectral index of the fluctuations is consistent with zero, the value expected for the CMB. The spectral index corresponding to Galactic free-free emission, the most likely foreground contaminant, is rejected at approximately $3\sigma$. The analysis is based on three independent data sets. The first, taken in 1993, spans the 26 - 36 GHz frequency range with three frequency bands; the second was taken with the same radiometer as the first but during an independent observing campaign in 1994; and the third, also take in 1994, spans the 36-46 GHz range in three bands. For each telescope position and radiometer channel, the drifts in the instrument offset are $\le 4~\mu$K/day over a period of one month. The dependence of the inferred anisotropy on the calibration and data editing is addressed.Comment: 16 pages, 2 figures. Saskatoon 1993/1994 combined analysi

Do Evaporating Black Holes Form Photospheres?

Several authors, most notably Heckler, have claimed that the observable Hawking emission from a microscopic black hole is significantly modified by the formation of a photosphere around the black hole due to QED or QCD interactions between the emitted particles. In this paper we analyze these claims and identify a number of physical and geometrical effects which invalidate these scenarios. We point out two key problems. First, the interacting particles must be causally connected to interact, and this condition is satisfied by only a small fraction of the emitted particles close to the black hole. Second, a scattered particle requires a distance ~ E/m_e^2 for completing each bremsstrahlung interaction, with the consequence that it is improbable for there to be more than one complete bremsstrahlung interaction per particle near the black hole. These two effects have not been included in previous analyses. We conclude that the emitted particles do not interact sufficiently to form a QED photosphere. Similar arguments apply in the QCD case and prevent a QCD photosphere (chromosphere) from developing when the black hole temperature is much greater than Lambda_QCD, the threshold for QCD particle emission. Additional QCD phenomenological arguments rule out the development of a chromosphere around black hole temperatures of order Lambda_QCD. In all cases, the observational signatures of a cosmic or Galactic halo background of primordial black holes or an individual black hole remain essentially those of the standard Hawking model, with little change to the detection probability. We also consider the possibility, as proposed by Belyanin et al. and D. Cline et al., that plasma interactions between the emitted particles form a photosphere, and we conclude that this scenario too is not supported.Comment: version published in Phys Rev D 78, 064043; 25 pages, 3 figures; includes discussion on extending our analysis to TeV-scale, higher-dimensional black hole

Effect of hyperon bulk viscosity on neutron-star r-modes

Neutron stars are expected to contain a significant number of hyperons in addition to protons and neutrons in the highest density portions of their cores. Following the work of Jones, we calculate the coefficient of bulk viscosity due to nonleptonic weak interactions involving hyperons in neutron-star cores, including new relativistic and superfluid effects. We evaluate the influence of this new bulk viscosity on the gravitational radiation driven instability in the r-modes. We find that the instability is completely suppressed in stars with cores cooler than a few times 10^9 K, but that stars rotating more rapidly than 10-30% of maximum are unstable for temperatures around 10^10 K. Since neutron-star cores are expected to cool to a few times 10^9 K within seconds (much shorter than the r-mode instability growth time) due to direct Urca processes, we conclude that the gravitational radiation instability will be suppressed in young neutron stars before it can significantly change the angular momentum of the star.Comment: final PRD version, minor typos etc correcte

Entanglement, recoherence and information flow in an accelerated detector - quantum field system: Implications for black hole information issue

We study an exactly solvable model where an uniformly accelerated detector is linearly coupled to a massless scalar field initially in the Minkowski vacuum. Using the exact correlation functions we show that as soon as the coupling is switched on one can see information flowing from the detector to the field and propagating with the radiation into null infinity. By expressing the reduced density matrix of the detector in terms of the two-point functions, we calculate the purity function in the detector and study the evolution of quantum entanglement between the detector and the field. Only in the ultraweak coupling regime could some degree of recoherence in the detector appear at late times, but never in full restoration. We explicitly show that under the most general conditions the detector never recovers its quantum coherence and the entanglement between the detector and the field remains large at late times. To the extent this model can be used as an analog to the system of a black hole interacting with a quantum field, our result seems to suggest in the prevalent non-Markovian regime, assuming unitarity for the combined system, that black hole information is not lost but transferred to the quantum field degrees of freedom. Our combined system will evolve into a highly entangled state between a remnant of large area (in Bekenstein's black hole atom analog) without any information of its initial state, and the quantum field, now imbued with complex information content not-so-easily retrievable by a local observer.Comment: 16 pages, 12 figures; minor change

Compton Heating of the Intergalactic Medium by the Hard X-ray Background

High-resolution hydrodynamics simulations of the Ly-alpha forest in cold dark matter dominated cosmologies appear to predict line widths that are substantially narrower than those observed. Here we point out that Compton heating of the intergalactic gas by the hard X-ray background (XRB), an effect neglected in all previous investigations, may help to resolve this discrepancy. The rate of gain in thermal energy by Compton scattering will dominate over the energy input from hydrogen photoionization if the XRB energy density is 0.2x/ times higher than the energy density of the UV background at a given epoch, where x is the hydrogen neutral fraction in units of 1e-6 and is the mean X-ray photon energy in units of m_ec^2. The numerical integration of the time-dependent rate equations shows that the intergalactic medium approaches a temperature of about 1.5e4 K at z>3 in popular models for the redshift evolution of the extragalactic background radiation. The importance of Compton heating can be tested experimentally by measuring the Ly-alpha line-width distribution as a function of redshift, thus the Lyman-alpha forest may provide a useful probe of the evolution of the XRB at high redshifts.Comment: LaTeX, 10 pages, 2 figures, final version to be published in the Ap

Agnesi Weighting for the Measure Problem of Cosmology

The measure problem of cosmology is how to assign normalized probabilities to observations in a universe so large that it may have many observations occurring at many different spacetime locations. I have previously shown how the Boltzmann brain problem (that observations arising from thermal or quantum fluctuations may dominate over ordinary observations if the universe expands sufficiently and/or lasts long enough) may be ameliorated by volume averaging, but that still leaves problems if the universe lasts too long. Here a solution is proposed for that residual problem by a simple weighting factor 1/(1+t^2) to make the time integral convergent. The resulting Agnesi measure appears to avoid problems other measures may have with vacua of zero or negative cosmological constant.Comment: 26 pages, LaTeX; discussion is added of how Agnesi weighting appears better than other recent measure

Transient Observers and Variable Constants, or Repelling the Invasion of the Boltzmann's Brains

If the universe expands exponentially without end, ``ordinary observers'' like ourselves may be vastly outnumbered by ``Boltzmann's brains,'' transient observers who briefly flicker into existence as a result of quantum or thermal fluctuations. One might then wonder why we are so atypical. I show that tiny changes in physics--for instance, extremely slow variations of fundamental constants--can drastically change this result, and argue that one should be wary of conclusions that rely on exact knowledge of the laws of physics in the very distant future.Comment: 4 pages, LaTeX; v2: added references; v3: more discussion of setting, alternative approaches, now 5 pages; v4: added discussion of the effect of quantum fluctuations on varying constants, appendix added, now 7 pages; v5: new reference, minor correctio

Information in Black Hole Radiation

If black hole formation and evaporation can be described by an $S$ matrix, information would be expected to come out in black hole radiation. An estimate shows that it may come out initially so slowly, or else be so spread out, that it would never show up in an analysis perturbative in $M_{Planck}/M$, or in 1/N for two-dimensional dilatonic black holes with a large number $N$ of minimally coupled scalar fields.Comment: 12 pages, 1 PostScript figure, LaTeX, Alberta-Thy-24-93 (In response to Phys. Rev. Lett. referees' comments, the connection between expansions in inverse mass and in 1/N are spelled out, and a figure is added. An argument against perturbatively predicting even late-time information is also provided, as well as various minor changes.