41,381 research outputs found
Midyear update: major metros driving Texas expansion
Federal Reserve Bank of Dallas ; Business cycles ; Maquiladora ; Employment ; Unemployment ; Retail trade
A survey of the effect of grooved runway operations on the wear of commercial airline tires
Effect of grooved runway operations on wear of commercial airline tire
The Z-index: A geometric representation of productivity and impact which accounts for information in the entire rank-citation profile
We present a simple generalization of Hirsch's h-index, Z =
\sqrt{h^{2}+C}/\sqrt{5}, where C is the total number of citations. Z is aimed
at correcting the potentially excessive penalty made by h on a scientist's
highly cited papers, because for the majority of scientists analyzed, we find
the excess citation fraction (C-h^{2})/C to be distributed closely around the
value 0.75, meaning that 75 percent of the author's impact is neglected.
Additionally, Z is less sensitive to local changes in a scientist's citation
profile, namely perturbations which increase h while only marginally affecting
C. Using real career data for 476 physicists careers and 488 biologist careers,
we analyze both the distribution of and the rank stability of Z with
respect to the Hirsch index h and the Egghe index g. We analyze careers
distributed across a wide range of total impact, including top-cited physicists
and biologists for benchmark comparison. In practice, the Z-index requires the
same information needed to calculate h and could be effortlessly incorporated
within career profile databases, such as Google Scholar and ResearcherID.
Because Z incorporates information from the entire publication profile while
being more robust than h and g to local perturbations, we argue that Z is
better suited for ranking comparisons in academic decision-making scenarios
comprising a large number of scientists.Comment: 9 pages, 5 figure
Isomorphism and embedding of Borel systems on full sets
A Borel system consists of a measurable automorphism of a standard Borel
space. We consider Borel embeddings and isomorphisms between such systems
modulo null sets, i.e. sets which have measure zero for every invariant
probability measure. For every t>0 we show that in this category there exists a
unique free Borel system (Y,S) which is strictly t-universal in the sense that
all invariant measures on Y have entropy <t, and if (X,T) is another free
system obeying the same entropy condition then X embeds into Y off a null set.
One gets a strictly t-universal system from mixing shifts of finite type of
entropy at least t by removing the periodic points and "restricting" to the
part of the system of entropy <t. As a consequence, after removing their
periodic points the systems in the following classes are completely classified
by entropy up to Borel isomorphism off null sets: mixing shifts of finite type,
mixing positive-recurrent countable state Markov chains, mixing sofic shifts,
beta shifts, synchronized subshifts, and axiom-A diffeomorphisms. In particular
any two equal-entropy systems from these classes are entropy conjugate in the
sense of Buzzi, answering a question of Boyle, Buzzi and Gomez.Comment: 17 pages, v2: correction to bibliograph
Binomial-coefficient multiples of irrationals
Denote by a random infinite path in the graph of Pascal's triangle (left
and right turns are selected independently with fixed probabilities) and by
the binomial coefficient at the 'th level along the path . Then
for a dense set of in the unit interval, is almost surely dense but not uniformly distributed modulo 1.Comment: 10 pages, to appear in Monatshefte f. Mat
Influence of Temperature on the Physiology and Virulence of the Insect Pathogen Serratia sp. Strain SCBI
The physiology of a newly recognized Serratia species, termed South African Caenorhabditis briggsae Isolate (SCBI), which is both a nematode mutualist and an insect pathogen, was investigated and compared to that of Serratia marcescens Db11, a broad-host-range pathogen. The two Serratia strains had comparable levels of virulence for Manduca sexta and similar cytotoxic activity patterns, but motility and lipase and hemolytic activities differed significantly between them
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