Are you in control?

Overcramped conditions and lack of available storage space are usually the instigating factors for implementation of a micrographics system, but there are many other benefits to be gained, It is critical that a system be well planned and carefully researched to assure that you are indeed in control. If your only goal is to microfilm records to make more space, this space will also be "jammed" within a short period of time and you will have accomplished nothing. A good micrographics system can, and should, improve the integrity of the records, in addition to saving space. It should and will provide control of the records, while at the same time making the information readily available to all users. The system can be combined with an existing computer system within the facility and/or be shared with other departments. An ill-planned micrographics system will ultimately lead to one that is neither cost-effective nor efficient.     

Are there basic laws of quantum information processing?

We prove within the quantum formalism without reduction postulate that the no-cloning theorem and the principle of no-increasing of entanglement (in a bit weaker formulations) are equivalent. We argue that the result is a manifestation of more general principles governing quantum information processing analogous to the thermodynamical laws.     

Are there phase transitions in information space?

The interplay between two basic quantities--quantum communication and information--is investigated. Quantum communication is an important resource for quantum states shared by two parties and is directly related to entanglement. Recently, the amount of local information that can be drawn from a state has been shown to be closely related to the nonlocal properties of the state. Here we consider both formation and extraction processes, and analyze informational resources as a function of quantum communication. The resulting diagrams in information space allow us to observe phaselike transitions when correlations become classical.     

Are there waves in elastic wave turbulence?

An thin elastic steel plate is excited with a vibrator and its local velocity displays a turbulentlike Fourier spectrum. This system is believed to develop elastic wave turbulence. We analyze here the motion of the plate with a two-point measurement in order to check, in our real system, a few hypotheses required for the Zakharov theory of weak turbulence to apply. We show that the motion of the plate is indeed a superposition of bending waves following the theoretical dispersion relation of the linear wave equation. The nonlinearities seem to efficiently break the coherence of the waves so that no modal structure is observed. Several hypotheses of the weak turbulence theory seem to be verified, but nevertheless the theoretical predictions for the wave spectrum are not verified experimentally.     

Are there tachyons in extensive air showers?

The results obtained by studying double-front extensive air showers in which more than 107 particles are contained and in which the fronts are separated by a time interval of Δt ∼ 100 ns are presented. Serious difficulties in explaining “delayed” showers are revealed. In this connection, a hypothesis that the “leading” showers are initiated by tachyons produced in the first interaction of primary particles is proposed.     

Are quantum fields cellular automata?

Tesselation of the quantum field and local connectivity of the cellular automaton type is investigated. A connection between this class of models and lattice field theory is established. Nonlocal models are briefly discussed.     

Are there phase transitions in liquid metallic alloys?

Recently, resistivity measurements of some liquid metals and metallic alloys have been obtained using an electrode technique. A marked change of the slope of the resistivity versus temperature has been observed following the history of the alloy in the liquid state and the authors conclude that there are “structural transitions in the melt”. It is of interest to examine such effects and to try to understand their origin. In this work, the resistivities of several liquid metals and metallic alloys were measured as a function of temperature. Particular attention was given to the history of the alloy, including solidification and melting conditions. We also observed “anomalies”. Our experiments lead us to conclude that they must very probably be attributed to the release of gas or vapour bubbles in the liquid alloy at the first heating, resulting from the decomposition of compounds like oxides or hydroxides of the metals, but not from a phase transition in the liquid metallic state involving “breaking” Sn–Sn covalent bands.     

Are there acoustic plasmons?

A survey of theoretical research on acoustic plasmons is given and prospects for the observation of these elusive modes are examined. Possible acoustic plasmon contributions to the transition temperatures of the superconducting A-15 compounds are considered. Directions for future experiments and theory are suggested.     

Are the native states of proteins kinetic traps?

Four proteins were selected to represent each of the four different CATH classes and, for each protein, three decoys were constructed with structures totally alien to the native state. The decoys were scored against the native state with the help of the AMBER force field, using three measures: the average energy, the average fluctuation and the resistance to a heat pulse. Two sets of simulations were performed, one with explicit solvent and the other with implicit solvent. The overall conclusion is that, of these three measures, the most successful in picking out the native states was the last one, since the native structures take a consistently longer time to be destabilized in this manner. However, the general conclusion is also that none of the measures is completely effective in discriminating all the decoys, a result that supports other studies, according to which the native state is reached by a kinetic step.     

Are there three vacuum trajectories?

Recent experiments suggest the existence of a I^G = 0⁺, J^P = 2⁺ meson of mass 1085 MeV. Consequently we are prompted to propose the existence of three high-lying Regge trajectories with vacuum quantum numbers. A qualitative comparison of this hypothesis with elastic scattering measurements is favourable, and underlines the importance of acquiring further data on the new resonance.     

Are there Efimov trimers in hexafluorobenzene rather than in benzene vapor itself?

Is there a spectroscopic method to detect an Efimov state? Following our proposal of an Efimov state arising from three pseudo bosons (generalized Cooper pairs) in benzene, our spectroscopic studies have found no evidence of Efimov trimers (ET) in h₆- or d₆-benzene. However, hexafluoro-benzene has shown peaks that we attributed to ET and the pseudo bosons. The experimental evidence suggests that benzene pseudo bosons and subsequently ET are quite sensitive to the surroundings.     

Is there a fundamental limit on the key distribution distance in quantum cryptography?

Is there a fundamental limit on the key distribution distance in quantum cryptography? Are there quantum key distribution protocols approaching this limit and how close can they approach this limit? The answer to the first question is both yes and no. A general answer to the first question can be given without considering a particular quantum key distribution protocol and its implementation. The answer to the second question is given by a particular protocol for which the distribution distance is close to the theoretical limit and the achievement of this value is limited by our possibilities of correcting errors using classical codes rather than by the quantum key distribution protocol itself.     

Are there anomalous Z fermion couplings?

The couplings of the fermions to the Z boson are of great importance in establishing the validity of the Standard Model and in looking for physics beyond it. The couplings of the b-quark to the Z boson have been the subject of much experimental study and theoretical interpretation. The apparent excess in the value of , the ratio of the partial width of the Z boson to to its total hadronic width, above the Standard Model expectation reported a few years ago has now become much less significant. However, the measurements of the pole forward-backward asymmetry for b-quarks at the Z pole and of the polarisation parameter , obtained using a polarised electron beam, have improved considerably in accuracy. The latest data are examined and values of the vector and axial-vector b-quark and c-quark couplings to the Z are extracted. The left and right handed couplings are also extracted. It is found that whereas the c-quark couplings are compatible with the Standard Model, those of the b-quark data are only compatible with the Standard Model at about the 1% level. In addition, the individual lepton couplings are extracted and the degree to which the data support the hypothesis of lepton universality is discussed. The sensitivity of the limits from electroweak fits to the Higgs boson mass to these data is examined. Received: 21 December 1998 / Revised version: 12 February 1999 / Published online: 15 April 1999     

Are there S = -2 pentaquarks?

Recent evidence for pentaquark baryons in the channels , and their anti-particles claimed by the NA49 collaboration is critically confronted with the vast amount of existing data on spectroscopy which was accumulated over the past decades. It is shown that the claim is inconsistent with these data. In addition two further exotic channels of the pentaquark type available in the NA49 data are investigated. It is argued that this study leads to internal inconsistency with the purported signals.Received: 16 January 2004, Published online: 24 August 2004 Correspondence to: S. Wenig     

Are there sterile neutrinos in the flux of solar neutrinos on the earth?

It is shown that the future SNO and Super-Kamiokande experiments, in which high energy⁸B neutrinos will be detected through the observation of CC, NC and –e elastic scattering processes, could allow to reveal in a model independent way the presence of sterile neutrinos in the flux of solar neutrinos on the earth. Lower bounds for different averaged values of the probability of transition of solar v^e'S into sterile states and for the total flux of⁸B neutrinos are derived in terms of measurable quantities. The possibilities to reveal the presence of v and/or v in the solar neutrino flux on the earth are also considered and the case of transitions of solar v^e'S only into sterile states is discussed. Some numerical results for a simple model with v–v^s mixing are given.     

Are there any models with homogeneous energy density?

By applying a recent method—based on a tetrad formalism in General Relativity and the orthogonal splitting of the Riemann tensor—to the simple spherical static case, we found that the only static solution with homogeneous energy density is the Schwarzschild solution and that there are no spherically symmetric dynamic solutions consistent with the homogeneous energy density assumption. Finally, a circular equivalence is shown among the most frequent conditions considered in the spherical symmetric case: homogeneous density, isotropy in pressures, conformally flatness and shear-free conditions. We demonstrate that, due to the regularity conditions at the center of the matter distribution, the imposition of two conditions necessarily leads to the static case.