12,685 research outputs found
The influence of food availability, predation risk, and metabolic costs on the evolutionary stability of diel vertical migration in zooplankton
Enlargeability and index theory
Let M be a closed enlargeable spin manifold. We show non-triviality of the
universal index obstruction in the K-theory of the maximal -algebra of the
fundamental group of M. Our proof is independent from the injectivity of the
Baum-Connes assembly map for the fundamental group of M and relies on the
construction of a certain infinite dimensional flat vector bundle out of a
sequence of finite dimensional vector bundles on M whose curvatures tend to
zero.
Besides the well known fact that M does not carry a metric with positive
scalar curvature, our results imply that the classifying map
sends the fundamental class of M to a nontrivial homology class in H_n(B
\pi_1(M) ; \Q). This answers a question of Burghelea (1983).Comment: 32 pages, final version accepted for publication, added relation to
Gromov's 1-systole, typos corrected; to appear in Journal of Differential
Geometr
On the structuralist view of inflation in some Latin American countries: A reassessment
Comparing inflation rates internationally, one finds a number of Latin American countries in the lead. Therefore, when investigating inflation in LDCs, it has become common practice to refer to these countries as prime examples. Mainly two theories have been put forward to explain Latin American inflation: the monetarist and structuralist hypotheses. While in the monetarist theory aggregate excess demand resulting from an excess supply of money is regarded as the only cause of inflation, the structuralist theory ascribes inflation also to the composition of demand for products and services accompanied by inflexibilities in the productive structure. The purpose of this paper is to give further empirical evidence for the structuralist view of inflation in six selected Latin American countries: Bolivia, Brazil, Chile, Colombia, Ecuador and Peru. They have all been highly prone to inflation in the past. First, we outline the theoretical background of our investigation. Subsequently, empirical tests of the hypotheses are provided. Finally, we draw some conclusions from our study and relate the findings to the discussion of the harmful effects of export instability in LDCs.
The Impact of rising international interest rates on developing countries: The South Korean experience
This paper evaluates the impact of rising international interest rates on the South Korean economy during the seventies with the help of an econometric macro model. The results show that there was an induced reduction of investment and GDP, yet inflationary pressures were somewhat mitigated by a lowering of capital inflows.
How neutron stars constrain the nuclear equation of state
Recent neutron star observations set new constraints for the equation of
state of baryonic matter. A chiral effective field theory approach is used for
the description of neutron-dominated nuclear matter present in the outer core
of neutron stars. Possible hybrid stars with quark matter in the inner core are
discussed using a three-flavor Nambu--Jona-Lasinio model.Comment: Conference Proceedings for INPC 2013, Florence; 4 pages, 4 figure
The space of metrics of positive scalar curvature
We study the topology of the space of positive scalar curvature metrics on
high dimensional spheres and other spin manifolds. Our main result provides
elements of infinite order in higher homotopy and homology groups of these
spaces, which, in contrast to previous approaches, are of infinite order and
survive in the (observer) moduli space of such metrics.
Along the way we construct smooth fiber bundles over spheres whose total
spaces have non-vanishing A-hat-genera, thus establishing the
non-multiplicativity of the A-hat-genus in fibre bundles with simply connected
base.Comment: 24 pages, v2: minor additions and corrections, based in particular on
comments of referees, v3: minor corrections, final version, to appear in
Publ.Math. IHE
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