20,656 research outputs found
International Assistance and Cooperation in Sexual and Reproductive Health: a Human Rights Responsibility for Donors
On the magnetic field of off-limb spicules
Determining the magnetic field related to solar spicules is vital for
developing adequate models of these plasma jets, which are thought to play a
key role in the thermal, dynamic and magnetic structure of the Chromosphere.
Here we report on the magnetic properties of off-limb spicules in a very quiet
region of the solar atmosphere, as inferred from new spectropolarimetric
observations in the He I 10830 A triplet obtained with the Tenerife Infrared
Polarimeter. We have used a novel inversion code for Stokes profiles caused by
the joint action of atomic level polarization and the Hanle and Zeeman effects
(HAZEL) to interpret the observations. Magnetic fields as strong as ~40G were
detected in a very localized area of the slit, which could represent a possible
lower value of the field strength of organized network spicules.Comment: Accepted for publication in ApJ, 24 pages, 5 Figure
Contractions, Hopf algebra extensions and cov. differential calculus
We re-examine all the contractions related with the
deformed algebra and study the consequences that the contraction process has
for their structure. We also show using
as an example that, as in the undeformed case, the contraction may generate
Hopf algebra cohomology. We shall show that most of the different Hopf algebra
deformations obtained have a bicrossproduct or a cocycle bicrossproduct
structure, for which we shall also give their dual `group' versions. The
bicovariant differential calculi on the deformed spaces associated with the
contracted algebras and the requirements for their existence are examined as
well.Comment: TeX file, 25 pages. Macros are include
Potencial de utilização de parasitóide de ovos no controle de lagartas e sua associação com o controle químico.
Effective actions, relative cohomology and Chern Simons forms
The explicit expression of all the WZW effective actions for a simple group G
broken down to a subgroup H is established in a simple and direct way, and the
formal similarity of these actions to the Chern-Simons forms is explained.
Applications are also discussed.Comment: 11 pages. Latex2e file. Published versio
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