194 research outputs found

    Long Cycles in a Perturbed Mean Field Model of a Boson Gas

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    In this paper we give a precise mathematical formulation of the relation between Bose condensation and long cycles and prove its validity for the perturbed mean field model of a Bose gas. We decompose the total density ρ=ρshort+ρlong\rho=\rho_{{\rm short}}+\rho_{{\rm long}} into the number density of particles belonging to cycles of finite length (ρshort\rho_{{\rm short}}) and to infinitely long cycles (ρlong\rho_{{\rm long}}) in the thermodynamic limit. For this model we prove that when there is Bose condensation, ρlong\rho_{{\rm long}} is different from zero and identical to the condensate density. This is achieved through an application of the theory of large deviations. We discuss the possible equivalence of ρlong0\rho_{{\rm long}}\neq 0 with off-diagonal long range order and winding paths that occur in the path integral representation of the Bose gas.Comment: 10 page

    A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

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    Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Velocity-space sensitivity of the time-of-flight neutron spectrometer at JET

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    The velocity-space sensitivities of fast-ion diagnostics are often described by so-called weight functions. Recently, we formulated weight functions showing the velocity-space sensitivity of the often dominant beam-target part of neutron energy spectra. These weight functions for neutron emission spectrometry (NES) are independent of the particular NES diagnostic. Here we apply these NES weight functions to the time-of-flight spectrometer TOFOR at JET. By taking the instrumental response function of TOFOR into account, we calculate time-of-flight NES weight functions that enable us to directly determine the velocity-space sensitivity of a given part of a measured time-of-flight spectrum from TOFOR

    Relationship of edge localized mode burst times with divertor flux loop signal phase in JET

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    A phase relationship is identified between sequential edge localized modes (ELMs) occurrence times in a set of H-mode tokamak plasmas to the voltage measured in full flux azimuthal loops in the divertor region. We focus on plasmas in the Joint European Torus where a steady H-mode is sustained over several seconds, during which ELMs are observed in the Be II emission at the divertor. The ELMs analysed arise from intrinsic ELMing, in that there is no deliberate intent to control the ELMing process by external means. We use ELM timings derived from the Be II signal to perform direct time domain analysis of the full flux loop VLD2 and VLD3 signals, which provide a high cadence global measurement proportional to the voltage induced by changes in poloidal magnetic flux. Specifically, we examine how the time interval between pairs of successive ELMs is linked to the time-evolving phase of the full flux loop signals. Each ELM produces a clear early pulse in the full flux loop signals, whose peak time is used to condition our analysis. The arrival time of the following ELM, relative to this pulse, is found to fall into one of two categories: (i) prompt ELMs, which are directly paced by the initial response seen in the flux loop signals; and (ii) all other ELMs, which occur after the initial response of the full flux loop signals has decayed in amplitude. The times at which ELMs in category (ii) occur, relative to the first ELM of the pair, are clustered at times when the instantaneous phase of the full flux loop signal is close to its value at the time of the first ELM

    The stratigraphy of the Inferior Oolite at South Main Road Quarry, Dundry, Avon

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    A new section opened on the site of the former South Main Road Quarry, Dundry, Avon, is described. The biostratigraphy of the ammonite succession has been revised through careful bed-by-bed collecting and is presented in a range chart. It is recast in the form of a sequence of discrete ammonite fauna! horizons as has become customary in the classical areas of Somerset and Dorset first described in this way by Buckman. One new ammonite faunal horizon has been identified in the Lower Bajocian: Bj-10b, Sonninia micracanthica (Buckman). This carries several of what have been regarded in the past as leading guide-fossils of the Sauzei Zone. But it is now seen to be also the type horizon of the index of the Laeviuscula Zone, Witchellia laeviuscula. It is therefore retained in the Laeviuscula Zone as its youngest horizon on grounds of nomenclatural stability. The basal boundary of the overlying Sauzei Zone is drawn above it and its lowest ammonite horizon renamed, Bj-11a, Stephanoceras kalum (Buckman). The systematics of some important species based on types from Dundry are reviewed briefly and the origins and phylogeny of some important ammonite genera of the Ovale to Sauzei Zones are discussed. The succession of forms of Witchellia is now separated as a phyletic subfamily Witchelliinae subf. nov. within the polyphyletic clade of the Sonniniidae. A new species of Emileia, E. dundriensis, is described from the Laeviuscula Zone. The nautiloids are also reviewed briefly
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