6,042 research outputs found
On the size of the Fe II emitting region in the AGN Akn 120
We present a reverberation analysis of the strong, variable optical Fe II
emission bands in the spectrum of Akn 120, a low-redshift AGN which is one of
the best candidates for such a study. On time scales of several years the Fe II
line strengths follow the variations in the continuum strength. However, we are
unable to measure a clear reverberation lag time for these Fe II lines on any
time scale. This is due to the very broad and flat-topped nature of the Fe II
cross correlation functions, as compared to the H-beta response which is much
more sharply localized in time. Although there is some suggestion in the light
curve of a 300-day response time, our statistical analysis does not pick up
such a feature. We conclude that the optical Fe II emission does not come from
a photoionization-powered region similar in size to the H-beta emitting region,
but we cannot say for sure where it does come from. Our results are generally
consistent either with emission from a photoionized region several times larger
than the H-beta zone, or with emission from gas heated by some other means,
perhaps responding only indirectly to the continuum variations.Comment: Accepted for publication in the Ap
INVESTIGATING THE THERAPEUTIC POTENTIAL OF CANNABIGEROL (CBG) IN FEMALE NONALCOHOLIC STEATOHEPATITIS (NASH) MOUSE MODEL
Nonalcoholic Steatohepatitis (NASH) is a progressive form of nonalcoholic fatty liver disease (NAFLD) characterized by inflammation, fibrosis, steatosis, and oxidative stress, in addition to excessive fat accumulation in the liver. Cannabigerol (CBG), a precursor molecule of Cannabidiol (CBD), has demonstrated anti-inflammatory and anti-oxidative effects in various studies. Our previous data showed that a low dosage of CBG reduced inflammation and fibrosis in male NASH mice. However, the impact of CBG on female mice remains unknown. Recent studies have identified changes in immune cell populations in NAFLD patients. The goal of this project was to test the impact of CBG treatment in alleviating the risks related to methioninecholine deficient (MCD) diet induced NASH in female mice. Here, we evaluated the efficacy of low and high doses of CBG as a novel therapeutic option for ameliorating NASH-associated inflammation, ductular reaction, fibrosis, oxidative stress, and steatosis in a female mouse model induced by the MCD diet. We also determined changes in the immune cell population of nonparenchymal cells (NPC) caused by CBG treatment. Although there wasn\u27t a significant change in the liver-to-body weight ratio of female mice, we observed an overall improvement in liver health, manifested as reduced leukocyte infiltration, after treatment with both low and high doses of CBG. The experimental mice that received CBG interventions did not exhibit significant changes in the heightened hepatic ballooning or steatosis observed in the MCD-treated NASH female mice. However, both low and high doses of CBG treatment significantly reduced fibrosis, oxidative stress, ductular proliferation, and inflammation levels. In the groups treated with low and high doses of CBG, we noted a considerable reduction in the number of monocytes and T lymphocytes. Moreover, we conducted a partial study on the CBG’s signaling pathway. We found that CBG downregulates the activation of mast cells, thereby inhibiting the release of transforming growth factor (TGF-β1). This, in turn, suppresses the activation of hepatic stellate cells, resulting in a reduction in collagen deposition and subsequently decreasing fibrosis and ductular proliferation. The results of this study provide valuable insights for designing future interventions in pre-clinical and clinical research, particularly concerning the potential use and dosage of CBG to address liver fibrosis and inflammation in female patients
The Impact of New Technologies on the Environment
One of the objectives of IIASA's Study "Future Environments for Europe: Some Implications of Alternative Development Paths" is to characterize the large-scale and long-term environmental transformations that could be associated with plausible scenarios of Europe's socio-economic development over the next century. The purpose of this task is to help foresee potentially serious environmental problems before they actually occur. This Working Paper is an important contribution toward that goal.
It is becoming increasingly clear that the linkages between technologies and their long-term effects on the environment require more careful attention and forethought than has been the case in the past. The socio-economic benefits of technologies are usually proportional to their scale of application, and the rewards are reaped almost instantaneously. The problem, however, is that the "disbenefits", in terms of ecological degradation, often very nonlinearly with the scale of application, and are manifested on relatively slow time scales. The danger of this syndrome is that the technology may tend to become entrenched over time, making it difficult for adjustment or change by the time the disbenefits become manifest.
Therefore, this timely paper should be of interest to all those who ponder the long-term trade-offs between technological development and environmental degradation
Brazilian Atlantic Forest Lato Sensu: The Most Ancient Brazilian Forest, And A Biodiversity Hotspot, Is Highly Threatened By Climate Change.
After 500 years of exploitation and destruction, the Brazilian Atlantic Forest has been reduced to less the 8% of its original cover, and climate change may pose a new threat to the remnants of this biodiversity hotspot. In this study we used modelling techniques to determine present and future geographical distribution of 38 species of trees that are typical of the Brazilian Atlantic Forest (Mata Atlântica), considering two global warming scenarios. The optimistic scenario, based in a 0.5% increase in the concentration of CO2 in the atmosphere, predicts an increase of up to 2 °C in the Earth's average temperature; in the pessimistic scenario, based on a 1% increase in the concentration of CO2 in the atmosphere, temperature increase may reach 4 °C. Using these parameters, the occurrence points of the studied species registered in literature, the Genetic Algorithm for Rule-set Predictions/GARP and Maximum entropy modeling of species geographic distributions/MaxEnt we developed models of present and future possible occurrence of each species, considering Earth's mean temperature by 2050 with the optimistic and the pessimistic scenarios of CO2 emission. The results obtained show an alarming reduction in the area of possible occurrence of the species studied, as well as a shift towards southern areas of Brazil. Using GARP, on average, in the optimistic scenario this reduction is of 25% while in the pessimistic scenario it reaches 50%, and the species that will suffer the worst reduction in their possible area of occurrence are: Euterpe edulis, Mollinedia schottiana, Virola bicuhyba, Inga sessilis and Vochysia magnifica. Using MaxEnt, on average, in the optimistic scenario the reduction will be of 20% while in the pessimistic scenario it reaches 30%, and the species that will suffer the worst reduction are: Hyeronima alchorneoides, Schefflera angustissima, Andira fraxinifolia and the species of Myrtaceae studied.70697-70
Observation and inverse problems in coupled cell networks
A coupled cell network is a model for many situations such as food webs in
ecosystems, cellular metabolism, economical networks... It consists in a
directed graph , each node (or cell) representing an agent of the network
and each directed arrow representing which agent acts on which one. It yields a
system of differential equations , where the component
of depends only on the cells for which the arrow
exists in . In this paper, we investigate the observation problems in
coupled cell networks: can one deduce the behaviour of the whole network
(oscillations, stabilisation etc.) by observing only one of the cells? We show
that the natural observation properties holds for almost all the interactions
Exponential decay for the damped wave equation in unbounded domains
We study the decay of the semigroup generated by the damped wave equation in
an unbounded domain. We first prove under the natural geometric control
condition the exponential decay of the semigroup. Then we prove under a weaker
condition the logarithmic decay of the solutions (assuming that the initial
data are smoother). As corollaries, we obtain several extensions of previous
results of stabilisation and control
On Quasar Masses and Quasar Host Galaxies
The mass of massive black holes in quasar cores can be deduced using the
typical velocities of Hb-emitting clouds in the Broad Line Region (BLR) and the
size of this region. However, this estimate depends on various assumptions and
is susceptible to large systematic errors. The Hb-deduced black hole mass in a
sample of 14 bright quasars is found here to correlate with the quasar host
galaxy luminosity, as determined with the Hubble Space Telescope (HST). This
correlation is similar to the black hole mass vs. bulge luminosity correlation
found by Magorrian et al. in a sample of 32 nearby normal galaxies. The
similarity of the two correlations is remarkable since the two samples involve
apparently different types of objects and since the black hole mass estimates
in quasars and in nearby galaxies are based on very different methods.
This similarity provides a ``calibration'' of the Hb-deduced black hole mass
estimate, suggesting it is accurate to +-0.5 on log scale. The similarity of
the two correlations also suggests that quasars reside in otherwise normal
galaxies, and that the luminosity of quasar hosts can be estimated to +-0.5 mag
based on the quasar continuum luminosity and the Hb line width. Future imaging
observations of additional broad-line active galaxies with the HST are required
in order to explore the extent, slope, and scatter of the black hole mass vs.
host bulge luminosity correlation in active galaxies.Comment: Accepted for publication in ApJ Letters, 7 pages, aas2pp4.st
The Challenge Of Including Chemodiversity, And The Potential Economic Use Of New Natural Compounds And Processes, In The Biota/fapesp Program
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