215,024 research outputs found
Two houses: legislative studies and the Atlantic divide
Legislative scholars have a history of stepping back occasionally to examine the development and state of the sub-discipline (Budge 1973; Gamm and Huber 2002; Loewenberg, Patterson, and Jewell 1985; Mezey 1993; Morris-Jones 1983; Pasquino 1973; Patterson 1989). Many of these existing reviews, although valuable, are predominantly of a qualitative and subjective nature and are, in most cases, now dated. This paper provides a bibliometrical analysis of the state of legislative studies in the United States and Europe by exploring the content of eight political science journals. I looked at six general political science journals, three originating in the United States and three in Europe, as well as the content of two legislative studies journalsâthe American-based Legislative Studies Quarterly and the British-based Journal of Legislative Studies
Supermassive black holes as sources for LISA
Some issues relevant for the formation of supermassive black holes are
discused and estimates of the event rates for the emission of gravitational
waves by coalescing supermassive black hole binaries are given. The models take
into account recent improvements in our knowledge of galaxy and star formation
in the high-redshift universe. Estimated event rates range from a few to a
hundred per year. Typical events will occur at redshift three or larger in
galaxies lying at the (very) faint end of the luminosity function at these
redshifts.Comment: 5 pages, LaTeX, 2 postscript figures included; invited talk at the
Second International LISA Symposium, Pasadena, July 1998 (ed. W. Folkner,
American Institute of Physics
A Two Term Truncation of the Multiple Ising Model Coupled to 2d Gravity
We consider a model of p independent Ising spins on a dynamical planar
phi-cubed graph. Truncating the free energy to two terms yields an exactly
solvable model that has a third order phase transition from a pure gravity
region (gamma=-1/2) to a tree-like region (gamma=1/2), with gamma=1/3 on the
critical line. We are able to make an order of magnitude estimate of the value
of p above which there exists a branched polymer (ie tree-like) phase in the
full model, that is, p is approximately 13-23, which corresponds to a central
charge c of about 6-12.Comment: 18 pages, LaTeX, 12 figure
Sequence motifs that distinguish ATP(CTP) : tRNA nucleotidyl transferases from eubacterial poly(A) polymerases
ATP(CTP):tRNA nucleotidyl transferases, tRNA maturing enzymes found in all organisms, and eubacterial poly(A) polymerases, enzymes involved in mRNA degradation, are so similar that until now their biochemical functions could not be distinguished by their amino acid sequence. BLAST searches and analysis with the program "Sequence Space" for the prediction of functional residues revealed sequence motifs which define these two protein families. One of the poly(A) polymerase defining motifs specifies a structure that we propose to function in binding the 3' terminus of the RNA substrate. Similar motifs are found in other homopolyribonucleotidyl transferases. Phylogenetic classification of nucleotidyl tranferases from sequenced genomes reveals that eubacterial poly(A) polymerases have evolved relatively recently and are found only in a small group of bacteria and surprisingly also in plants, where they may function in organelles
Large scale simulations of the jet-IGM interaction
In a parameter study extending to jet densities of times the
ambient one, I have recently shown that light large scale jets start their
lives in a spherical bow shock phase. This allows an easy description of the
sideways bow shock propagation in that phase. Here, I present new, bipolar,
simulations of very light jets in 2.5D and 3D, reaching the observationally
relevant scale of jet radii. Deviations from the early bow shock
propagation law are expected because of various effects. The net effect is,
however, shown to remain small. I calculate the X-ray appearance of the shocked
cluster gas and compare it to Cygnus A and 3C 317. Rings, bright spots and
enhancements inside the radio cocoon may be explained.Comment: 8 pages, 5 figures, ApSS accepted, proceedings of the virtual jets
2003 conference in Dogliani/Italy, v3: funny and unimportant bug corrected,
one reference adde
Unintegrated parton distributions and electroweak boson production at hadron colliders
We describe the use of doubly-unintegrated parton distributions in
hadron-hadron collisions, using the (z,k_t)-factorisation prescription where
the transverse momentum of the incoming parton is generated in the last
evolution step. We apply this formalism to calculate the transverse momentum
(P_T) distributions of produced W and Z bosons and compare the predictions to
Tevatron Run 1 data. We find that the observed P_T distributions can be
generated almost entirely by the leading order q_1 q_2 -> W,Z subprocesses,
using known and universal doubly-unintegrated quark distributions. We also
calculate the P_T distribution of the Standard Model Higgs boson at the LHC,
where the dominant production mechanism is by gluon-gluon fusion.Comment: 20 pages, 8 figures. Version to appear in Phys. Rev. D; correction to
Higgs P_T distribution made in Erratu
Effect of absorptive corrections on inclusive parton distributions
We study the effect of absorptive corrections due to parton recombination on
the parton distributions of the proton. A more precise version of the GLRMQ
equations, which account for non-linear corrections to DGLAP evolution, is
derived. An analysis of HERA F_2 data shows that the small-x gluon distribution
is enhanced at low scales when the absorptive effects are included, such that a
negative gluon distribution at 1 GeV is no longer required.Comment: 10 pages, 3 figure
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