Hartree-Fock-Bogoliubov Calculations of the Rotational Band of the Very Heavy 254^{254}No Nucleus

We report on Hartree-Fock-Bogoliubov (HFB) calculations of the ground-state rotationnal band of the heavy nucleus $^{254}$No recently observed experimentally. The calculated quadrupole deformation is consistent with the experimental value of $\beta=0.27$ and is almost constant over the whole band. We also reproduce fairly well the excitation spectra and moments of inertia of this isotope up to the maximal experimentally observed state of spin 20. The rather high stability of this nucleus against fission is illustrated by the deformation energy curve providing very high fission barriers at zero spin within the HFB and HFB plus Lipkin-Nogami formalisms. The variation of these barriers with increased angular velocities is also studied.Comment: 4 pages (LaTeX), submitted to Eur. Phys. J A, dedicated to the memory of J. Piperov

A simple model for the quenching of pairing correlations effects in rigidly deformed rotational bands

Using Chandrasekhar's S-type coupling between rotational and intrinsic vortical modes one may simply reproduce the HFB dynamical properties of rotating nuclei within Routhian HF calculations free of pairing correlations yet constrained on the relevant so-called Kelvin circulation operator. From the analogy between magnetic and rotating systems, one derives a model for the quenching of pairing correlations with rotation, introducing a critical angular velocity -- analogous to the critical field in supraconductors -- above which pairing vanishes. Taking stock of this usual model, it is then shown that the characteristic behavior of the vortical mode angular velocity as a function of the global rotation angular velocity can be modelised by a simple two parameter formula, both parameters being completely determined from properties of the band-head (zero-spin) HFB solution. From calculation in five nuclei, the validity of this modelised Routhian approach is assessed. It is clearly shown to be very good in cases where the evolution of rotational properties is only governed by the coupling between the global rotation and the pairing-induced intrinsic vortical currents. It therefore provides a sound ground base for evaluating the importance of coupling of rotation with other modes (shape distortions, quasiparticle degrees of freedom).Comment: 10 pages, 8 figures. Submited to PR

MULTILATERAL GOVERNANCE OF FISHERIES: MANAGEMENT AND COOPERATION IN THE WESTERN AND CENTRAL PACIFIC TUNA FISHERIES

The tuna resources of the Western and Central Pacific are the world's largest and most valuable fisheries of their type and are of significant economic importance to the Pacific island countries through whose waters they migrate. Two major concerns exist with the current governance of this fishery. First, Pacific island countries receive only a small share of the resource rents from the tuna fisheries. Second, the current management structure of the fisheries will not ensure the long-term sustainability of the resources. This paper derives a model to show that the sustainability of the resource can be improved when a single policymaker acts as Stackelberg leader and sets a tax, or an equivalent quantity instrument, to maximize rents from the resource. A practical institutional mechanism is presented that mimics the model's rent maximization outcome and that offers substantial benefits to both Pacific island countries and distant water fishing nations.Resource /Energy Economics and Policy,

Time-resolved detection of relative intensity squeezed nanosecond pulses in a Rb87 vapor

We present theoretical and experimental results on the generation and detection of pulsed, relative-intensity squeezed light in a hot Rb87 vapor. The intensity noise correlations between a pulsed probe beam and its conjugate, generated through nearly-degenerate four-wave mixing in a double-lambda system, are studied numerically and measured experimentally via time-resolved balanced detection. We predict and observe about -1 dB of time-resolved relative intensity squeezing with 50 nanosecond pulses at 1 MHz repetition rate. (-1.34 dB corrected for loss).Comment: 11 pages, 9 figure

The Acute Toxicity of Some Pesticides to Fish

Author Institution: U.S. Department of Health, Education, and Welfare, Division of Water Supply and Pollution Control Public Health Service, Robert A. Taft Sanitary Engineering Center, Cincinnati, OhioAcute static bioassays were conducted with 13 pesticides to determine their comparative toxicity to fish. There was a wide range in the toxicity of these compounds with 96-hour TLm values ranging from 0.0033 to 4.0 mg/1. Of the compounds tested, Thiodan, a chlorinated hydrocarbon, and Thimet, an organic phosphorus pesticide, were the most toxic; and Bayer 29493, an organic phosphorus compound, and Fermate, a carbamate, were the least toxic. In about half of these static tests, toxicity increased significantly with an increase of exposure time from 24 to 96 hours. The toxicity of the organic phosphorus and chlorinated hydrocarbon compounds did not appear to be influenced by the water quality characteristics (pH, hardness, alkalinity) examined. The toxicity of two of the carbamates was influenced by water quality characteristics

Ligand binding to the dimeric hemoglobin from Scapharca inaequivalvis, a hemoglobin with a novel mechanism for cooperativity.

Abstract The homodimeric hemoglobin from Scapharca inaequivalvis has an unusual spatial arrangement of the subunits (Royer, W.E., Jr., Love, W.E., and Fenderson, F.F. (1985) Nature 316, 277-280). The time course of oxygen and nitric oxide rebinding to this protein following flash photolysis has been measured on a nanosecond time scale. A large amplitude is observed with a half-time of 20 ns (NO). With oxygen the half-time decreases from 70 ns at low fractional photolysis to 30 ns at large breakdown. The second order rate of NO binding is 1.6 x 10(7)/MS, and is the same as that for oxygen. Analysis of the geminate data suggests that oxygen and nitric oxide react more rapidly with the heme than in myoglobin, but also escape much more rapidly from its vicinity

Observations on rapidly reacting hemoglobin.

Abstract The time course of appearance of quickly reacting hemoglobin at pH 7 in dilute solutions (l10 µm in heme) was studied by means of a stopped flow-flash apparatus. When the flash is fired as soon as possible after the reaction of human deoxyhemoglobin with carbon monoxide or immediately after dilution of a concentrated human carbon monoxide hemoglobin solution, little of the quickly reacting form is present; the amount of quickly reacting material increases with time and reaches its final value in a few seconds. The results may be due to dissociation of ligand bound hemoglobin

Predictive factors of success at the French National Ranking Examination (NRE) : a retrospective study of the student performance from a French medical school

Background The national ranking examination (NRE) marks the end of the second cycle (6th university year) of French medical studies and ranks students allowing them to choose their specialty and city of residency. We studied the potential predictive factors of success at the 2015 NRE by students attending a French School of Medicine. Methods From March 2016 to March 2017, a retrospective study of factors associated with the 2015 NRE success was conducted and enrolled 242 students who attended their sixth year at the school of medicine of Reims. Demographic and academic data collected by a home-made survey was studied using univariate and then multivariate analysis by generalized linear regression with a threshold of p <  0.05 deemed significant. Results The factors independently associated with a better ranking at the NRE were the motivation for the preparation of the NRE (gain of 3327 ± 527 places, p <  0.0001); to have participated in the NRE white test organized by la Revue du Praticien in November 2014 (gain of 869 ± 426 places, p <  0.04), to have participated in the NRE white test organized by la conférence Hippocrate in March 2015 (+ 613 places ±297, p <  0.04). The factors independently associated with poor NRE ranking were repeating the first year (loss of 1410 places ±286, p <  0.0001), repeating a year during university course (loss of 1092 places ±385, p <  0.005), attendance of hospital internships in 6th year (loss of 706 places ±298, p <  0.02). Conclusions The student motivation and their white tests completion were significantly associated with success at the NRE. Conversely, repeating a university year during their course and attendance of 6th year hospital internships were associated with a lower ranking