Observational constraints on modified Chaplygin gas in Horava–Lifshitz gravity with dark radiation

Cosmological models with modified Chaplygin gas (MCG) in the framework of Horava–Lifshitz (HL) theory of gravity, both with and without detailed balance, are obtained. The equation of state (EOS) for a MCG contains three unknown parameters namely, A, α, B. The allowed values of some of these parameters of the EOS are determined using the recent astrophysical and cosmological observational data. Using observational data from H(z)-z, baryon acoustic oscillation (BAO) peak parameter and cosmic microwave background (CMB) shift parameter we study cosmologies in detailed-balance and beyond detailed-balance scenario. In this paper we take up the beyond detailed-balance scenario in totality and contribution of dark radiation in detailed-balance scenario on the parameters of the EOS. We explore the effect of dark radiation on the whole range of the effective neutrino parameter (ΔN _ν ) to constrain matter contributing parameter B in both the detailed-balance and the beyond detailed-balance scenarios. It has been observed that greater the dark radiation less the matter contribution in the MCG in both the scenario considered here. In order to check the validity of beyond detailed-balance scenario we plot supernovae magnitudes (μ) with red-shift of Union2 data and then the variation of state parameter with redshift is studied. It is noted that beyond detailed-balance scenario is suitable for cosmological model in HL gravity with MCG.     

MODELING AND MEASURING PRODUCTION PROCESSES FOR A MULTI‐SPECIES FISHERY: ALTERNATIVE TECHNICAL EFFICIENCY ESTIMATES FOR THE NORTHERN SPAIN HAKE FISHERY

ABSTRACT. The economic performance of fisheries is difficult to measure, due to the importance of (multi‐species) biological dynamics, property rights and regulatory issues affecting fishermen's behavior and efficiency. However, an understanding of performance patterns is essential for enhancing the economic and biological viability of fisheries. In this paper we estimate and evaluate alternative primal stochastic approaches to modeling and measuring technical efficiency for the Northern Spain hake fishery. We then compare the resulting efficiency measures to identify variations in their potential interpretation, and application to policy guidance. We find that multi‐output models are more theoretically and empirically justifiable than aggregate output production function models, and provide additional policy‐relevant insights, but that relative production and efficiency estimates are not sub‐stantively affected by model specification.     

DISTINGUISHED LINE BUNDLES FOR COMPLEX SURFACE AUTOMORPHISMS

We equate dynamical properties (e.g., positive entropy, existence of a periodic curve) of complex projective surface automorphisms with properties of the pull-back actions of such automorphisms on line bundles. We use the properties of the cohomological actions to describe the measures of maximal entropy for automorphisms with positive entropy.     

Antenna coupling study for ICWC plasma characterization in TEXTOR

Ion cyclotron wall conditioning (ICWC) discharges, in pulsed-mode operation, were carried out in the limiter tokamak TEXTOR to explore safe operational regimes for the experimental parameters for possible ICWC-discharge cleaning in International Thermonuclear Experimental Reactor (ITER) at half field. Antenna coupling properties obtained during the ion cyclotron range of frequencies (ICRF) wall conditioning experiments performed in helium–hydrogen mixture in TEXTOR were analysed in relation to the obtained ICWC-plasma characterization results. Satisfactory antenna coupling in the mode conversion scenario along with reproducible generation of ICRF plasmas for wall conditioning, were achieved by coupling radio frequency (RF) power from one or two ICRF antennas. The plasma breakdown results obtained in the TEXTOR tokamak have been compared with the predictions of a zero-dimensional RF plasma production model. The present study of ICWC emphasizes the beneficial effect of application of an additional (along with toroidal magnetic field) stationary vertical (B _V???B _T) or oscillating poloidal magnetic field (B _P???B _T) on antenna coupling and relevant plasma parameters.     

Determining surface free energies of crystals with highly disordered surfaces from simulation

A method for calculating surface free energies by gradually creating slabs from a simulation of bulk crystals is tested for three low index faces of a Lennard-Jones crystal at temperatures up to the melting point. The path by which the interactions between atoms in different slabs are turned off must be chosen with care; here it is done in three stages, first the interaction energy is reduced until the well in the pair potential is considerably less than kT, then the effective particle sizes are reduced and finally the interaction energy is reduced to zero. The results show a slow and steady decrease in the surface free energy with temperature, while both the surface energy and the surface entropy increase rapidly when the upper layers of the crystal disorder. There is no evidence for a first order surface roughening transition although the (111) surface shows a sharper onset of disorder than do the (110) and (100) surfaces.     

Magnetic field and spin effects from sequential p-type and d-type triplet mechanisms

CIDEP signals of semireduced thionine radicals produced by reacting thionine triplets with aniline and halogenated anilines were measured by time resolved CW and pulsed FT EPR. For aniline as quencher, the polarization was emissive while for 4-Br- and 3-I-aniline a time dependent change in polarization from emissive to enhanced absorption was observed. For 4-I-aniline the signals were in enhanced absorption for all delay times. The time and concentration dependence of the signals was analysed in terms of a sequential double triplet mechanism: polarization of the thionine triplet due to selective population of the molecular triplet substates (classical ‘p-type’ triplet mechanism) and modification of this polarization by substate selective, heavy atom induced depopulation of triplet exciplexes (triplet contact radical pairs) formed as intermediates in the triplet quenching by electron transfer (‘d-type’ triplet mechanism). A quantitative theoretical treatment that combines the time-integrated solution of the stochastic Liouville equations for precursor triplet and triplet exciplex with the kinetic rate equation of the bimolecular quenching process is presented. The equations derived allow the extraction of two polarization enhancement factors, V _d for the pure d-type and V _pd for the combined p- and d-type triplet mechanism from the concentration dependence of the time dependent CIDEP signals. The CIDEP curves and the previously observed magnetic field and heavy atom effects on the free radical yield can be quantitatively simulated with a consistent set of kinetic parameters.     

An argumentation-based approach to risk assesment

Reliable quantitative risk assessment requires the use of meaningfulstatistical data and well validated models for their interpretation.In certain domains, neither the data nor the validated modelsare available. Nevertheless, there may still be a requirementto generate a meaningful characterization of risk, presentedin a form which reflects the reliability and accuracy of thedata available. One such domain is the assessment of the potentialcarcinogenic risk in chemical compounds, and there are manyothers. Work is described which is underway to provide a soundframework for the qualitative assessment of risk using a computermodel of 'argumentation'. This work is being applied to thedevelopment of computer-based support for the assessment ofcarcinogenic risk.     

PRIMARY PHOTOCHEMISTRY OF PHOTOSYNTHESIS Report on a Conference held at Argonne National Laboratory, November 1971

In conclusion, the conference was judged to be extremely useful for the 230 persons who attended, and all departed with an optimistic enthusiasm about the certainty of progress in this field over the next 5 to 10 years. A statistic that perhaps represents a new record and should be shared to underscore the significance of the meeting to researchers in this area of photosynthesis is that out of 59 scheduled speakers all were in attendance and only one had to be replaced because of a commitment to take part in ceremonies for the 150th anniversary of a famous university in the East. From our experience with the form of the meeting, we feel that the open attendance but limited subject concept is a highly desirable meeting form and should be used for most scientific meetings.     

A Note on the WKB Method for Difference Equations

We consider the asymptotic solution of the second-order differenceequation y_n + 1 –2y_n + y_n–1 + Q_ny_n = 0, where Q_n= N^–Q(n/N), 0 < < 2, Q(s) being a differentiablefunction of s, and N a large parameter such that Q(n/N) variesby order unity as n varies by order N. A discrete WKB methodis proposed, the form of the asymptotic expansion being similarto that used in the conventional WKB method. A particular Q(s)is studied, for which results of the discrete WKB method arein agreement with the results from the approach due to Bremmer(1951).     

A REVIEW OF THE SPECTRAL SENSITIZATION OF SILVER HALIDES,PAST AND PRESENT*

Abstract— Some of the important historical steps leading to our present understanding of the spectral sensitization of silver halides are reviewed and a new modification of the theory of the electron transfer mechanism of spectral sensitization is discussed. It is proposed that it is not necessary for spectral sensitizing dyes to inject electrons directly into the conduction band of the silver halide in the primary step. The only energetic restriction for the primary act of spectral sensitization is suggested to be the simple reduction of surface silver ions. However, for the spectral sensitizing act to be recorded photographically, secondary processes must be favorable for the subsequent deep trapping of the electrons that arise from the ionization of single silver atoms produced from the initial spectral sensitizing act.