12,939 research outputs found
The continuum limit in the quenched approximation
Previous work at with quenched staggered quarks is extended with
new calculations at 5.85 and 6.15 on lattices up to . These
calculations allow a more detailed study of extrapolation in quark mass, finite
volume and lattice spacing than has heretofore been possible. We discuss how
closely the quenched spectrum approaches that of the real world.Comment: 4 pages, uuencoded compressed PostScript, contribution to Lattice '9
Releituras crĂticas para a histĂłria do pĂłs-abolição
Review of:
GLEDHILL, Sabrina. Travessias no Atlùntico Negro: reflexÔes sobre Booker T. Washington e Manuel R. Querino. Salvador: EDUFBA, 2020. 300 p.Resenha de:
GLEDHILL, Sabrina. Travessias no Atlùntico Negro: reflexÔes sobre Booker T. Washington e Manuel R. Querino. Salvador: EDUFBA, 2020. 300 p
EscravidĂŁo na Era da Emancipação:: VĂtimas e Rebeldes no TrĂĄfico Interno de Escravizados (Brasil, SĂ©culo XIX)
The trajectory from slavery to freedom is generally told in linear fashion, yet for thousands of Black people in the Americas, the last decades of slavery were a time of expanding bondage. In Brazil, an internal slave trade shifted over 200,000 people from struggling northeastern plantations to the south-central region, where commercial coffee agriculture was quickly becoming the nationâs principal export sector. Scholars are increasingly exploring the ways in which African descendants became agents of their own freedom in the Atlantic world, but such agency is less visible among the victims of domestic slave trades.
KEYWORDS: Brazil; slavery; abolition.A trajetĂłria da escravidĂŁo para a liberdade Ă© geralmente contada de forma linear, mas para milhares de negros nas AmĂ©ricas, as Ășltimas dĂ©cadas do sĂ©culo XIX foram uma Ă©poca de expansĂŁo da escravidĂŁo. No Brasil, o comĂ©rcio interno de escravizados deslocou mais de 200.000 pessoas das plantaçÔes do nordeste para a regiĂŁo centro-sul, onde a agricultura comercial de cafĂ© rapidamente se tornava o principal setor de exportação do paĂs. Cada vez mais, estudiosos tĂȘm discutido os modos pelos quais descendentes de africanos se tornavam agentes de sua liberdade no mundo atlĂąntico, no entanto, tal agĂȘncia Ă© menos visĂvel para as vĂtimas do trĂĄfico interno.
PALAVRAS-CHAVE: Brasil; escravidão; abolição
Electromagnetic Moments of the Baryon Decuplet
We compute the leading contributions to the magnetic dipole and electric
quadrupole moments of the baryon decuplet in chiral perturbation theory. The
measured value for the magnetic moment of the is used to determine
the local counterterm for the magnetic moments. We compare the chiral
perturbation theory predictions for the magnetic moments of the decuplet with
those of the baryon octet and find reasonable agreement with the predictions of
the large-- limit of QCD. The leading contribution to the quadrupole
moment of the and other members of the decuplet comes from one--loop
graphs. The pionic contribution is shown to be proportional to (and so
will not contribute to the quadrupole moment of nuclei), while the
contribution from kaons has both isovector and isoscalar components. The chiral
logarithmic enhancement of both pion and kaon loops has a coefficient that
vanishes in the limit. The third allowed moment, the magnetic octupole,
is shown to be dominated by a local counterterm with corrections arising at two
loops. We briefly mention the strange counterparts of these moments.Comment: Uses harvmac.tex, 15 pages with 3 PostScript figures packed using
uufiles. UCSD/PTH 93-22, QUSTH-93-05, Duke-TH-93-5
Magnetic moments of the SU(3) decuplet baryons in the chiral quark-soliton model
Magnetic moments of baryons are studied within the chiral quark soliton model
with special emphasis on the decuplet of baryons. The model is used to identify
all symmetry breaking terms proportional to . Sum rules for the
magnetic moments are derived. A ``model-independent'' analysis of the symmetry
breaking terms is performed and finally model calculations are presented, which
show the importance of the rotational corrections for cranking of
the soliton.Comment: 22 pages, RevTex. The final version accepted for publication in Phys.
Rev.
UBVI Surface Photometry of the Spiral Galaxy NGC 300 in the Sculptor Group
We present UBVI surface photometry for 20.'5 X 20.'5 area of a late-type
spiral galaxy NGC 300. In order to understand the morphological properties and
luminosity distribution characteristics of NGC 300, we have derived isophotal
maps, surface brightness profiles, ellipticity profiles, position angle
profiles, and color profiles. By merging the I-band data of our surface
brightness measurements with those of Boeker et al. (2002) based on Hubble
Space Telescope observations, we have made combined I-band surface brightness
profiles for the region of 0."02 < r < 500" and decomposed the profiles into
three components: a nucleus, a bulge, and an exponential disk.Comment: 16 pages(cjaa209.sty), Accepted by the Chinese J. Astron. Astrophys.,
Fig 2 and 8 are degraded to reduce spac
Baryon Decuplet to Octet Electromagnetic Transitions in Quenched and Partially Quenched Chiral Perturbation Theory
We calculate baryon decuplet to octet electromagnetic transition form factors
in quenched and partially quenched chiral perturbation theory. We work in the
isospin limit of SU(3) flavor, up to next-to-leading order in the chiral
expansion, and to leading order in the heavy baryon expansion. Our results are
necessary for proper extrapolation of lattice calculations of these
transitions. We also derive expressions for the case of SU(2) flavor away from
the isospin limit.Comment: 16 pages, 3 figures, revtex
Orbital Kondo Effect in CeLaB: Scaling Analysis
Peculiarity of the Kondo effect in CeLaB is investigated on
the basis of the scaling equations up to third order. For the case where the
- charge fluctuation enters in addition to the - one, the
effective exchange interaction becomes anisotropic with respect to the orbital
pseudospins which represent the two different orbitals in the ground
state. Because of different characteristic energies for electric and magnetic
tensors, scaling with the single Kondo temperature does not apply to physical
quantities such as the resistivity and magnetic susceptibility. Possibility of
a bizzare phase is pointed out where the RKKY interaction leads to the spin
ordering without orbital ordering. This phase serves as a candidate of the
phase IV which is observed to be isotropic magnetically.Comment: 10 pages, 4 eps figures, submitted to PR
Universal Behavior of Load Distribution in Scale-free Networks
We study a problem of data packet transport in scale-free networks whose
degree distribution follows a power-law with the exponent . We define
load at each vertex as the accumulated total number of data packets passing
through that vertex when every pair of vertices send and receive a data packet
along the shortest path connecting the pair. It is found that the load
distribution follows a power-law with the exponent ,
insensitive to different values of in the range, ,
and different mean degrees, which is valid for both undirected and directed
cases. Thus, we conjecture that the load exponent is a universal quantity to
characterize scale-free networks.Comment: 5 pages, 5 figures, revised versio
Transient growth and coupling of vortex and wave modes in self-gravitating gaseous discs
Flow nonnormality induced linear transient phenomena in thin self-gravitating
astrophysical discs are studied in the shearing sheet approximation. The
considered system includes two modes of perturbations: vortex and (spiral
density) wave. It is shown that self-gravity considerably alters the vortex
mode dynamics -- its transient (swing) growth may be several orders of
magnitude stronger than in the non-self-gravitating case and 2-3 times larger
than the transient growth of the wave mode. Based on this finding, we comment
on the role of vortex mode perturbations in a gravitoturbulent state. Also
described is the linear coupling of the perturbation modes, caused by the
differential character of disc rotation. The coupling is asymmetric -- vortex
mode perturbations are able to excite wave mode ones, but not vice versa. This
asymmetric coupling lends additional significance to the vortex mode as a
participant in spiral density waves and shocks manifestations in astrophysical
discs.Comment: 10 pages, 8 figure
- âŠ