The General Primordial Cosmic Perturbation

We consider the most general primordial cosmological perturbation in a universe filled with photons, baryons, neutrinos, and a hypothetical cold dark matter (CDM) component within the framework of linearized perturbation theory. We give a careful discussion of the different allowed modes, distinguishing modes which are regular at early times, singular at early times, or pure gauge. As well as the familiar growing and decaying adiabatic modes and the baryonic and CDM isocurvature modes we identify two {\it neutrino isocurvature} modes which do not seem to have been discussed before. In the first, the ratio of neutrinos to photons varies spatially but the net density perturbation vanishes. In the second the photon-baryon plasma and the neutrino fluid have a spatially varying relative bulk velocity, balanced so that the net momentum density vanishes. Possible mechanisms which could generate the two neutrino isocurvature modes are discussed. If one allows the most general regular primordial perturbation, all quadratic correlators of observables such as the microwave background anisotropy and matter perturbations are completely determined by a $5\times 5,$ real, symmetric matrix-valued function of co-moving wavenumber. In a companion paper we examine prospects for detecting or constraining the amplitudes of the most general allowed regular perturbations using present and future CMB data.Comment: 18 pages, 2 Postscript figures, uses revtex. Revised 2-2000 Minor errors corrected and some references adde

Constraining Isocurvature Perturbations with CMB Polarization

The role of cosmic microwave background (CMB) polarisation data in constraining the presence of primordial isocurvature modes is examined. While the MAP satellite mission will be unable to simultaneously constrain isocurvature modes and cosmological parameters, the PLANCK mission will be able to set strong limits on the presence of isocurvature modes if it makes a precise measurement of the CMB polarisation sky. We find that if we allow for the possible presence of isocurvature modes, the recently obtained BOOMERANG measurement of the curvature of the universe fails. However, a comparably sensitive polarisation measurement on the same angular scales will permit a determination of the curvature of the universe without the prior assumption of adiabaticity.Comment: 4pages, Latex with four eps figures. (Revised 18 Dec 2000. Minor typos corrected

How useful is consolidation of public sector entities' financial statements ?

Whether or not to consolidate financial statements is dealt with in IPSAS#6. This standard is by and large based on IAS#27. It deals with the criterion according to which an entity's financial statements should be considered and which consolidation technique should be used. However, it remains silent when it comes to exposing the reason why a public sector entity should consolidate its financial statements. The literature is almost as silent as IPSAS on this issue. Which means that there is a lack of both theoretical and empirical knowledge on this subject. This paper explores the usefulness of the consolidation of financial statements (CFS) for different categories of users. It aims at investigating for which purposes consolidation is most useful and whether enlarging the scope of the consolidate group serves these purposes. Five purposes are considered: information, decision- making, accountability, risk-assessment, statistics improvement. The paper also aims at investigating if some categories of users consider CFS more useful than others. The issue is essentially empirical. Therefore it is examined in light of the results of an in-person interviews. We surveyed 25members of parliament, officials, creditors, and consultants of the Swiss central government. The results show that consolidating FS is considered especially important and useful for risk- assessment, information and accountability and to a somewhat lesser extent for decision-making and statistics improvement. Extending the scope of CFS may improve the situation when it comes to statistics but it would only marginally make CFS more relevant for decision making. Consultants and, to a lesser extent, members of the finance ministry are those respondents who deem the scope enlargement to be the most useful

Observation of Modulated Quadrupolar Structures in PrPb3

Neutron diffraction measurements have been performed on the cubic compound PrPb3 in a [001] magnetic field to examine the quadrupolar ordering. Antiferromagnetic components with q=(1/2+-d 1/2 0), (1/2 1/2+-d 0) (d~1/8) are observed below the transition temperature TQ (0.4 K at H=0) whose amplitudes vary linear with H and vanish at zero field, providing the first evidence for a modulated quadrupolar phase. For H<1 T, a non-square modulated state persists even below 100 mK suggesting quadrupole moments associated with a Gamma3 doublet ground state to be partially quenched by hybridization with conduction electrons.Comment: Physical Review Letters, in press. 4 pages, 4 figure

Magnetoresistance in Heavily Underdoped YBa_2Cu_3O_{6+x}: Antiferromagnetic Correlations and Normal-State Transport

We report on a contrasting behavior of the in-plane and out-of-plane magnetoresistance (MR) in heavily underdoped antiferromagnetic (AF) YBa_2Cu_3O_{6+x} (x<0.37). The out-of-plane MR (I//c) is positive over most of the temperature range and shows a sharp increase, by about two orders of magnitude, upon cooling through the Neel temperature T_N. A contribution associated with the AF correlations is found to dominate the out-of-plane MR behavior for H//c from far above T_N, pointing to the key role of spin fluctuations in the out-of-plane transport. In contrast, the transverse in-plane MR (I//a(b);H//c) appears to be small and smooth through T_N, implying that the development of the AF order has little effect on the in-plane resistivity.Comment: 4 pages, 5 figures, accepted for publication in Phys.Rev.Let