14,991 research outputs found
European Economic and Monetary Union: Transitional Issues and Third-Stage Dilemmas. European Policy Papers #4
This paper considers two kinds of issues facing EMU. One concerns qualifications and membership: how qualifications are evaluated and which member states are likely to meet the criteria set for membership in the third stage of EMU in 1999. The other concerns the capacity of member states, individually and collectively, to deal with economic policy after the advent of the third stage. In particular, will they be able to address the long-term problems of low growth and high unemployment that afflict so much of Europe? In regard to the first issue, the paper suggests, for supporters of EMU, some reason for optimism. It is very likely that the third stage of EMU will begin on the first day of 1999 and also that the "euro-zone" that comes into being on that day will, in all likelihood, include a large number of member states - almost certainly as many as 8 and probably as many as 10 or 11. On the second issue - the capacity of EMU to address the long-term problems of low growth and high unemployment - the paper suggests some reason for concern and pessimism. Most of the member states participating in the third stage of EMU are likely to continue experiencing low growth and high unemployment. Neither monetary policy nor exchange rate policy is likely to be applied so as to generate any significant increase in the long-term rate of economic growth or any decrease in the high levels of unemployment that now exist in most of the likely "euro-zone" members. Moreover, the Treaty creates no institutional capacity for collective action in economic policy that might enable the member states participating in EMU to redress those problems, and there seems to be little desire in the EU as a whole to create that institutional capacity
Surface flux transport simulations: Effect of inflows toward active regions and random velocities on the evolution of the Sun's large-scale magnetic field
Aims: We aim to determine the effect of converging flows on the evolution of
a bipolar magnetic region (BMR), and to investigate the role of these inflows
in the generation of poloidal flux. We also discuss whether the flux dispersal
due to turbulent flows can be described as a diffusion process.
Methods: We developed a simple surface flux transport model based on
point-like magnetic concentrations. We tracked the tilt angle, the magnetic
flux and the axial dipole moment of a BMR in simulations with and without
inflows and compared the results. To test the diffusion approximation,
simulations of random walk dispersal of magnetic features were compared against
the predictions of the diffusion treatment.
Results: We confirm the validity of the diffusion approximation to describe
flux dispersal on large scales. We find that the inflows enhance flux
cancellation, but at the same time affect the latitudinal separation of the
polarities of the bipolar region. In most cases the latitudinal separation is
limited by the inflows, resulting in a reduction of the axial dipole moment of
the BMR. However, when the initial tilt angle of the BMR is small, the inflows
produce an increase in latitudinal separation that leads to an increase in the
axial dipole moment in spite of the enhanced flux destruction. This can give
rise to a tilt of the BMR even when the BMR was originally aligned parallel to
the equator
Comparative Behavior of \u3ci\u3ePyrellia Cyanicolor\u3c/i\u3e (Diptera: Muscidae) on the Moss \u3ci\u3eSplachnum Ampullaceum\u3c/i\u3e and on Substrates of Nutritional Value
(excerpt)
Entomophily is commonly associated with flowering plants and their pollen vectors, but also occurs in other groups of plants. Among fungi, several genera of Phallaceae offer food rewards to calliphorid and muscid flies, which inadvertently disperse the fungal spores (Ingold 1964). Bryhn (1897) first noted a relationship between various species ofDiptera and members of the moss family Splachnaceae. The nature of this interaction has been the subject of much speculation (Bequaert 1921, Erlanson 1935, Crum et aI. 1972, Koponen and Koponen 1977), but no experimental evidence has been collected
Inflows towards active regions and the modulation of the solar cycle: a parameter study
Aims: We aim to investigate how converging flows towards active regions
affect the surface transport of magnetic flux, as well as their impact on the
generation of the Sun's poloidal field. The inflows constitute a potential
non-linear mechanism for the saturation of the global dynamo and may contribute
to the modulation of the solar cycle in the Babcock-Leighton framework.
Methods: We build a surface flux transport code incorporating a parametrized
model of the inflows and run simulations spanning several cycles. We carry out
a parameter study to assess how the strength and extension of the inflows
affect the build-up of the global dipole field. We also perform simulations
with different levels of activity to investigate the potential role of the
inflows in the saturation of the global dynamo.
Results: We find that the interaction of neighbouring active regions can lead
to the occasional formation of single-polarity magnetic flux clumps
inconsistent with observations. We propose the darkening caused by pores in
areas of high magnetic field strength as a plausible mechanism preventing this
flux-clumping. We find that inflows decrease the amplitude of the axial dipole
moment by a , relative to a no-inflows scenario. Stronger (weaker)
inflows lead to larger (smaller) reductions of the axial dipole moment. The
relative amplitude of the generated axial dipole is about larger after
very weak cycles than after very strong cycles. This supports the inflows as a
non-linear mechanism capable of saturating the global dynamo and contributing
to the modulation of the solar cycle within the Babcock-Leighton framework
- âŠ