3,506 research outputs found
Local haemorrhage induced by Bothrops jararaca venom: relationship to neurogenic inflammation.
We investigated morphological alterations induced by s.c. injection of 2.5 microg of Bothrops jararaca venom in rats. Intense disorganisation of collagen fibres was observed 1 min after the venom injection, particularly at regions near vessels and nerves. Mast cells were degranulated, and erythrocytes were seen leaving venules throughout the endothelial junctions. At this time, damaged endothelial cells were not observed. In rats envenomed as above, but immediately after cardiorespiratory failure induced by deep ether anaesthesia, alterations in the connective tissue structures, as previously described, were not observed. The mediation of this haemorrhage was investigated by injecting the venom into the foot pad of mice and compared to the mediation of oedema. Local haemorrhage was significantly reduced in mice pre-treated with capsaicin or guanethidine or submitted to a surgical section of sciatic and saphenous nerves. In these animals, oedema was not affected. Groups treated with methysergide or morphine showed both haemorrhage and oedema significantly reduced. Indomethacin or dexamethasone pre-treatments significantly reduced the oedema, but not the haemorrhage. Moreover, in animals treated with promethazine or mepyramine, oedema and haemorrhage were not affected. These data suggest that local haemorrhage induced by Bothrops jararaca venom is partially controlled by serotonin and neurohumoral mediators. Furthermore, results indicate that haemorrhage and oedema are mediated by different pharmacological systems
Cosmological Properties of a Gauged Axion
We analyze the most salient cosmological features of axions in extensions of
the Standard Model with a gauged anomalous extra U(1) symmetry. The model is
built by imposing the constraint of gauge invariance in the anomalous effective
action, which is extended with Wess-Zumino counterterms. These generate
axion-like interactions of the axions to the gauge fields and a gauged shift
symmetry. The scalar sector is assumed to acquire a non-perturbative potential
after inflation, at the electroweak phase transition, which induces a mixing of
the Stuckelberg field of the model with the scalars of the electroweak sector,
and at the QCD phase transition. We discuss the possible mechanisms of
sequential misalignments which could affect the axions of these models, and
generated, in this case, at both transitions. We compute the contribution of
these particles to dark matter, quantifying their relic densities as a function
of the Stuckelberg mass. We also show that models with a single anomalous U(1)
in general do not account for the dark energy, due to the presence of mixed
U(1)-SU(3) anomalies.Comment: 29 pages, 5 figures. Revised version, accepted by Phys. Rev.
Comparação de meios de cultivo e métodos de extração na produção de lipÃdeos por Cryptococcus laurentii.
Selection of watermelon genotypes for resistance to bacterial fruit blotch.
Bacterial fruit blotch, caused by Acidovorax citrulli, is a serious threat to the watermelon crop in Brazil
Age estimation in children by measurement of open apices in teeth: a European formula
The aim of the present paper was to improve and
expand research with a larger number of children from various
European countries and to provide a common formula useful
for all these countries. Orthopantomographs taken from 2,652
European Caucasian children (1,382 boys, 1,270 girls) aged
between 4 and 16 years were analyzed. The children came from
Croatia, Germany, Kosovo, Italy, Slovenia, Spain, and the UK.
Following the pilot study, subjects’ age was modeled as a
function of gender (g), morphological variables (predictors)×5
(second premolar), s (sum of normalized open apices) N0, and
the first-order interaction between s and N0. The results
showed that all these variables contributed significantly to
the fit, so that all were included in the regression model,
yielding the following linear regression formula: Age=8.387+
0.282 g−1.692×5+0.835 N0−0.116 s−0.139 s×N0, where
g is a variable, 1 for males and 0 for females. The equation
explained 86.1% (R2=0.861) of total deviance. The median
of the residuals (=observed age minus predicted age) was
−0.114 years, with (RefB.2) interquartile range=1.22 years
Sobrevivência de Xanthomonas campestris pv. viticola em restos de poda de videira fragmentados e tratados com aceleradores de decomposição.
Suplemento. Edição dos Resumos do 44 Congresso Brasileiro de Fitopatologia, Bento Gonçalves, ago. 2011
Resistência de genótipos de melancia à mancha aquosa.
O objetivo da pesquisa foi avaliar o nÃvel de resistência de genótipos de melancia pertencentes ao Banco Ativo de Germoplasma de Cucurbitáceas para o Nordeste Brasileiro (BAG) da Embrapa Semiárido, em diferentes estádios de desenvolvimento da planta: sementes (74 genótipos), plântulas e plantas antes da floração (29 genótipos) e plantas durante a floração e frutificação (7 genótipos).Suplemento. Resumo 296. Edição do 45 Congresso Brasileiro de Fitopatologia, 2012, Manaus
On the use of scaling relations for the Tolman test
The use of relations between structural parameters of early type galaxies to
perform the Tolman test is reconsidered. Scaling relations such as the FP or
the Kormendy relation, require the transformation from angular to metric sizes,
to compare the relation at different z values. This transformation depends on
the assumed world model: galaxies of a given angular size, at a given z, are
larger (in kpc) in a non-expanding universe than in an expanding one.
Furthermore, the luminosities of galaxies are expected to evolve with z in an
expanding model. These effects are shown to conspire to reduce the difference
between the predicted SB change with redshift in the expanding and non
expanding cases. We find that the predictions for the visible photometric bands
of the expanding models with passive luminosity evolution are very similar to
those of the static model till z about 1, and therefore, the test cannot
distinguish between the two world models. Recent good quality data are
consistent with the predictions from both models. In the K-band, where the
expected (model) luminosity evolutionary corrections are smaller, the
differences between the xpanding and static models amount to about 0.4 (0.8)
magnitudes at z = 0.4 (1). It is shown that, due to that small difference
between the predictions in the covered z-range, and to the paucity and
uncertainties of the relevant SB photometry, the existing K-band data is not
adequate to distinguish between the different world metrics, and cannot be yet
used to discard the static case. It is pointed out that the scaling relations
could still be used to rule out the non-evolving case if it could be shown that
the coefficients change with the redshift.Comment: Latex, 15 pages with 2 figures. To be published in ApJ Letter
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