143 research outputs found
Espaços ficcionalizados no romance Desterro:memórias em ruÃnas de LuÃs Sérgio Krausz: um ensaio em geografia literária
O escritor bávaro-brasileiro Zé do Rock, nômade quixotesco, terror da ortografia e da sáude pública
Effects of cold winters and roost site stability on population development of non-native Asian ring-necked parakeets (Alexandrinus manillensis) in temperate Central Europe – Results of a 16-year census
Asian ring-necked parakeets (Alexandrinus manillensis, formerly Psittacula krameri, hereafter RNP) first bred in Germany in 1969. Since then, RNP numbers increased in all three major German subpopulations (Rhineland, Rhine-Main, Rhine-Neckar) over the period 2003–2018. In the Rhine-Neckar region, the population increased to more than fivefold within only 15 years. Interestingly, there was no significant breeding range expansion of RNP in the period 2010–2018. In 2018, the total number of RNP in Germany amounted to >16,200 birds. Differences in RNP censuses between years were evident. Surprisingly, cold winters (extreme value, −13.7 °C) and cold weather conditions in the breeding season (coldest month average, −1.36 °C) were not able to explain between-year variation. This finding suggests that in general winter mortality is low – with exceptions for winters 2008/2009 and 2009/2010, and a population-relevant loss of broods is low in our study population. Surprisingly, the social behaviour in terms of spatio-temporal stability of roost sites could well explain positive and negative population trends. Years of spatially stable and regularly used roost sites seem to correlate with increasing population sizes. In contrast, known shifts of RNP among different roost sites or the formations of new roost sites by split are related to population stagnation or a decrease in numbers. Climate change may lead to further range expansion as cities not suitable yet for RNP may become so in the near future.
The spiral structure of the Galaxy revealed by CS sources and evidence for the 4:1 resonance
We present a map of the spiral structure of the Galaxy, as traced by
molecular CS emission associated with IRAS sources which are believed to be
compact HII regions. The CS line velocities are used to determine the kinematic
distances of the sources, in order to investigate their distribution in the
galactic plane. This allows us to use 870 objects to trace the arms, a number
larger than that of previous studies based on classical HII regions. The
distance ambiguity of the kinematic distances, when it exists, is solved by
different procedures, including the latitude distribution and an analysis of
the longitude-velocity diagram. The well defined spiral arms are seen to be
confined inside the co-rotation radius, as is often the case in spiral
galaxies. We identify a square-shaped sub-structure in the CS map with that
predicted by stellar orbits at the 4:1 resonance (4 epicycle oscillations in
one turn around the galactic center). The sub-structure is found at the
expected radius, based on the known pattern rotation speed and epicycle
frequency curve. An inner arm presents an end with strong inward curvature and
intense star formation that we tentatively associate with the region where this
arm surrounds the extremity of the bar, as seen in many barred galaxies.
Finally, a new arm with concave curvature is found in the Sagitta to Cepheus
region of the sky
Galaxy Evolution and Star Formation Efficiency at 0.2 < z < 0.6
We present the results of a CO line survey of 30 galaxies at moderate
redshift (z \sim 0.2-0.6), with the IRAM 30m telescope, with the goal to follow
galaxy evolution and in particular the star formation efficiency (SFE) as
defined by the ratio between far-infrared luminosity and molecular gas mass
(LFIR/M(H2)). The sources are selected to be ultra-luminous infrared galaxies
(ULIRGs), with LFIR larger than 2.8 10^{12} Lsol, experiencing starbursts;
adopting a low ULIRG CO-to-H2 conversion factor, their gas consumption
time-scale is lower than 10^8 yr. To date only very few CO observations exist
in this redshift range that spans nearly 25% of the universe's age.
Considerable evolution of the star formation rate is already observed during
this period. 18 galaxies out of our sample of 30 are detected (of which 16 are
new detections), corresponding to a detection rate of 60%. The average CO
luminosity for the 18 galaxies detected is L'CO = 2 10^{10} K km/s pc^2,
corresponding to an average H2 mass of 1.6 10^{10} Msol. The FIR luminosity
correlates well with the CO luminosity, in agreement with the correlation found
for low and high redshift ULIRGs. Although the conversion factor between CO
luminosity and H2 mass is uncertain, we find that the maximum amount of gas
available for a single galaxy is quickly increasing as a function of redshift.
Using the same conversion factor, the SFEs for z\sim 0.2-0.6 ULIRGs are found
to be significantly higher, by a factor 3, than for local ULIRGs, and are
comparable to high redshift ones. We compare this evolution to the expected
cosmic H2 abundance and the cosmic star formation history.Comment: 11 pages, 13 figures, accepted in A&
Nitric oxide orchestrates metabolic rewiring in M1 macrophages by targeting aconitase 2 and pyruvate dehydrogenase.
Profound metabolic changes are characteristic of macrophages during classical activation and have been implicated in this phenotype. Here we demonstrate that nitric oxide (NO) produced by murine macrophages is responsible for TCA cycle alterations and citrate accumulation associated with polarization. 13C tracing and mitochondrial respiration experiments map NO-mediated suppression of metabolism to mitochondrial aconitase (ACO2). Moreover, we find that inflammatory macrophages reroute pyruvate away from pyruvate dehydrogenase (PDH) in an NO-dependent and hypoxia-inducible factor 1α (Hif1α)-independent manner, thereby promoting glutamine-based anaplerosis. Ultimately, NO accumulation leads to suppression and loss of mitochondrial electron transport chain (ETC) complexes. Our data reveal that macrophages metabolic rewiring, in vitro and in vivo, is dependent on NO targeting specific pathways, resulting in reduced production of inflammatory mediators. Our findings require modification to current models of macrophage biology and demonstrate that reprogramming of metabolism should be considered a result rather than a mediator of inflammatory polarization
CO emission in optically obscured (type-2) quasars at redshifts z=0.1-0.4
We present a search for CO emission in a sample of ten type-2 quasar host
galaxies with redshifts of z=0.1-0.4. We detect CO(J=1-0) line emission with
>=5sigma in the velocity integrated intensity maps of five sources. A sixth
source shows a tentative detection at the ~4.5sigma level of its CO(J=1-0) line
emission. The CO emission of all six sources is spatially coincident with the
position at optical, infrared or radio wavelengths. The spectroscopic redshifts
derived from the CO(J=1-0) line are very close to the photometric ones for all
five detections except for the tentative detection for which we find a much
larger discrepancy. We derive gas masses of ~(2-16)x10^9Msun for the CO
emission in the six detected sources, while we constrain the gas masses to
upper limits of Mgas<=8x10^9Msun for the four non-detections. These values are
of the order or slightly lower than those derived for type-1 quasars. The line
profiles of the CO(J=1-0) emission are rather narrow (<=300km/s) and single
peaked, unveiling no typical signatures for current or recent merger activity,
and are comparable to that of type-1 quasars. However, at least one of the
observed sources shows a tidal-tail like emission in the optical that is
indicative for an on-going or past merging event.
We also address the problem of detecting spurious ~5sigma emission peaks
within the field of view.Comment: accepted for publication in ApJ; 10 pages, 6 figures, 4 tables;
format is emulateap
Wenn biblische und biografische Fluchtgeschichten sich verweben : Bibliolog als Raum für Fluchterfahrungen
Antioxidant Machinery Differs between Melanic and Light Nestlings of Two Polymorphic Raptors
Colour polymorphism results from the expression of multiallelic genes generating phenotypes with very distinctive colourations. Most colour polymorphisms are due to differences in the type or amount of melanins present in each morph, which also differ in several behavioural, morphometric and physiological attributes. Melanin-based colour morphs could also differ in the levels of glutathione (GSH), a key intracellular antioxidant, because of the role of this molecule in melanogenesis. As GSH inhibits the synthesis of eumelanin (i.e. the darkest melanin form), individuals of darker morphs are expected to have lower GSH levels than those of lighter morphs. We tested this prediction in nestlings of two polymorphic raptors, the booted eagle Hieraaetus pennatus and the Eleonora's falcon Falco eleonorae, both of which occur in two morphs differing in the extent of eumelanic plumage. As expected, melanic booted eagle nestlings had lower blood GSH levels than light morph eagle nestlings. In the Eleonora's falcon, however, melanic nestlings only had lower GSH levels after controlling for the levels of other antioxidants. We also found that melanic female eagle nestlings had higher levels of antioxidants other than GSH and were in better body condition than light female eagle nestlings. These findings suggest an adaptive response of melanic nestlings to compensate for reduced GSH levels. Nevertheless, these associations were not found in falcons, indicating species-specific particularities in antioxidant machinery. Our results are consistent with previous work revealing the importance of GSH on the expression of melanic characters that show continuous variation, and suggest that this pathway also applies to discrete colour morphs. We suggest that the need to maintain low GSH levels for eumelanogenesis in dark morph individuals may represent a physiological constraint that helps regulate the evolution and maintenance of polymorphisms
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