Commentary on The recession of 2001 and unemployment insurance financing

Proceedings of a Conference Cosponsored by the Canadian Consulate General in New York, the Centre for the Study of Living Standards, the Federal Reserve Bank of New York, and the New York Association for Business Economics.Unemployment insurance ; Recessions ; Labor market

Stellar Velocity Dispersion and Black Hole Mass in the Blazar Markarian 501

The recently discovered correlation between black hole mass and stellar velocity dispersion provides a new method to determine the masses of black holes in active galaxies. We have obtained optical spectra of Markarian 501, a nearby gamma-ray blazar with emission extending to TeV energies. The stellar velocity dispersion of the host galaxy, measured from the calcium triplet lines in a 2"x3.7" aperture, is 372 +/- 18 km/s. If Mrk 501 follows the M-sigma correlation defined for local galaxies, then its central black hole has a mass of (0.9-3.4)x10^9 solar masses. This is significantly larger than some previous estimates for the central mass in Mrk 501 that have been based on models for its nonthermal emission. The host galaxy luminosity implies a black hole of 6x10^8 solar masses, but this is not in severe conflict with the mass derived from the M-sigma relation because the M_BH-L_bulge correlation has a large intrinsic scatter. Using the emission-line luminosity to estimate the bolometric luminosity of the central engine, we find that Mrk 501 radiates at an extremely sub-Eddington level of L/L_Edd ~ 10^-4. Further applications of the M-sigma relation to radio-loud active galactic nuclei may be useful for interpreting unified models and understanding the relationship between radio galaxies and BL Lac objects.Comment: To appear in ApJ Letters. 5 pages, 2 figure

Part I Electrochemically induced reactions of some halogenated organic compounds Part II novel rearrangements of pyridazine derivatives

The reduction of pentafluoropyridine gave, as the major products, octafluoro-4,4'-bipyridyl in aprotic systems and 4-H-tetrafluoropyridine with added proton donor. Garbanionic intermediates were not trapped by carbon dioxide to give acids. Voltammetric results for a series of polyfluoropyridines suggest that the negative charge in the radical anion is mainly in the 4-position. Reduotion of pentaohloropyridine in dime thylformamide gave 4-H-tetrachloropyridine, with some 4,4'-bistetraohloropyridylmeroury when using a mercury cathode. Intermediate carbanions were trapped by carbon dioxide, giving an acid mixture, which yielded 4-H-tetrachloropyridine and heptachlorobipyridyl on decarboxylation. Hexaohlorobenzene behaved similarly. Simple perfluoro-olefins eliminated fluoride ion on reduction and were subsequently oligomerised by it. Intermediate carbanions were trapped by water. The electrochemical products were high-boiling oils, resulting from reaction with the solvent. Oxidation of polyfluoroanisoles containing para hydrogen gave coupling to the corresponding 4,4'-dimethoxybiphenyl derivative. No coupling occurred when this position was blocked by fluorine. Trapping of intermediate radical cations with acetic acid was unproductive. PART II The photochemical and thermal rearrangements of a number of perfluoroalkylpyridazines in static systems was investigated. As had previously been reported, photolysis of perfluoro-4,5-dialkyl- pyridazines gave mainly perf1uoro-2,6-dialkylpyrazines, although in some cases perfluoro-2,6-dlal]sylpyrazines were also formed. The pyrolysis of perfluoro-4,5-clialkylpyridazines gave mainly perfluoro-4,5-dialkylpyrimidines and in some cases a small amount of the -2,5-pyrazine. Perfluoro-4-alkylpyridazines gave mixtures of perfluoro- 4-alkyl- and -5-alkylpyrimidines. These results can be explained by a mechanism involving diazabenzvalene Intermediates. The photolysis and pyrolysis of mixtures gave no exchange of substituent groups indicative of a bimolecular process. In the pyrolyses, the conversios of the less reactive pyridazlne was catalysed and that of the more reactive pyrldazlne Inhibited. The relative amounts rearranged ruled out a 1 : 1 Intermediate and a Slels-Alder mechanism, which would involve exchange of nitrogen, was further ruled out by (^15)N-labelling. The catalytic mechanism proposed Involves a transfer of vibrational excitation

Trapped modes of the Helmholtz equation in infinite waveguides with wall indentations and circular obstacles

Trapped modes of the Helmholtz equation are investigated in infinite, two-dimensional acoustic waveg- uides with Neumann or Dirichlet walls. A robust boundary element scheme is used to study modes both inside and outside the continuous spectrum of propagating modes. An effective method for distinguishing between genuine trapped modes and spurious solutions induced by the domain truncation is presented. The method is also suitable for the detection and study of “nearly trapped modes” (NTM). These are of great practical importance as they display many features of trapped modes but do not require perfect geometry. An infinite, two-dimensional channel is considered with one or two discs on its centreline. The walls may have rectangular, triangular or smooth cavities. The combination of a circular obstacle and a rectangular cavity, in both Neumann and Dirichlet guides is studied, illustrating the possible use of a movable disc to detect wall irregularities. The numerical method is validated against known results and many new modes are identified, both inside and outside the continuous spectrum. Results obtained suggest that at least one symmetry line is an important condition for the formation of trapped mode type resonances. The addition of a symmetry- preserving geometric parameter to a problem which has a discrete embedded trapped mode solution for a specific geometry, tends to lead to a continuous set of trapped modes

Letter from C. S. Sargent to John Muir, 1894 Jan 8.

ARNOLD ARBORETUM,HARVARD UNIVERSITY.Jamaica Plain Mass., January 8, 1894My dear Mr. Muir:Thank you. The Silva is coming on slowly. The fifth volume appeared in October and the sixth is fairly on the way. I am working hard at it in order to get it off my hands in time to pay you a visit this spring. I should have accomplished this easily if the grip had not got the best of me in December and caused me to lose nearly a month\u27s time. However, I still want to get away, if I can, in time to see something of the Spring vegetation of California which will be quite new to me.Planned it [illegible] a dozen years [illegible] - 1893When we meet we can talk over that trip to India which I am still keen for, and all the more so if I can have the pleasure of your company.We often think and speak of your visit to Brookline and I hope the time is not far distant when you will come and see us again. I am glad you had such a good time on the other side of the ocean.With kind regards,I am,always faithfully yours,C. S. Sargent.John Muir, Esq.,Martinez, Cal.0176

The ratio of carbon dioxide consumption to oxygen evolution in sea water in the light

The production of organic matter in sea water by the phytoplankton community has frequently been computed (Nielsen, 1937; Riley 1941) by measuring the oxygen evolution in bottled sea water samples and calculating the organic matter on the assumption that the phytoplankton organisms produced glucose by photosynthesis according to the equation:..