736 research outputs found
Environmental Issues, Economic Interests, and Legal Solutions
This paper seeks to provide lines of approach and hypotheses for a historical and geographic contextualisation of the jurisprudential texts of the Digest. It focuses upon the matter of water sharing in rural landscapes. After examining different landscapes, it argues that legal
solutions proposed by Roman jurists originally applied to the situation of competition for natural resources observed in the periphery of Rome and were linked with the development of the city between the 3rd and 2nd centuries BC
A Genome-Wide Analysis Reveals Significant Overlap of Transcription and DNA Repair in Stationary Phase Yeast
The association between transcription and DNA repair is acknowledged as a player in the generation of mutations in a non-random fashion in prokaryotes and eukaryotes. Previous studies demonstrated that the transcription complex is capable of directing DNA repair to sites of transcription. This process is especially important to growth-arrested cells, in which many DNA repair capacities are diminished; it may also lead to mutations preferentially in transcribed genes. Using microarray analysis of growth-arrested yeast cultures, we demonstrated on a genomic scale, the co-localization of a DNA-turnover marker, indicative of DNA-repair-associated DNA synthesis, with genes persistently transcribed during stationary phase. This may serve as a clue regarding the non-random manner in which non-dividing cells may potentially mutate in the absence of replication, solely as a result of their inherent, transcriptional stress response
An Olfactory Receptor Pseudogene whose Function emerged in Humans
Human olfactory receptor, hOR17-210, is identified as a pseudogene in the human genome. Experimental data has shown however, that the gene product of cloned hOR17-210 cDNA was able to bind an odorant-binding protein and is narrowly tuned for excitation by cyclic ketones. Supported by experimental results, we used the bioinformatics methods of sequence analysis, computational protein modeling and docking, to show that functionality in this receptor is retained due to sequence-structure features not previously observed in mammalian ORs. This receptor does not possess the first two transmembrane helical domains (of seven typically seen in GPCRs). It however, possesses an additional TM that has not been observed in other human olfactory receptors. By incorporating these novel structural features, we created two putative models for this receptor. We also docked odor ligands that were experimentally shown to bind hOR17-210 model. We show how and why structural modifications of OR17-210 do not hinder this receptor's functionality. Our studies reveal that novel gene rearrangement that result in sequence and structural diversity in has a bearing on OR and GPCR function and evolution
The GALEX Arecibo SDSS Survey. VIII. Final Data Release -- The Effect of Group Environment on the Gas Content of Massive Galaxies
We present the final data release from the GALEX Arecibo SDSS Survey (GASS),
a large Arecibo program that measured the HI properties for an unbiased sample
of ~800 galaxies with stellar masses greater than 10^10 Msun and redshifts
0.025<z<0.05. This release includes new Arecibo observations for 250 galaxies.
We use the full GASS sample to investigate environmental effects on the cold
gas content of massive galaxies at fixed stellar mass. The environment is
characterized in terms of dark matter halo mass, obtained by cross-matching our
sample with the SDSS group catalog of Yang et al. Our analysis provides, for
the first time, clear statistical evidence that massive galaxies located in
halos with masses of 10^13-10^14 Msun have at least 0.4 dex less HI than
objects in lower density environments. The process responsible for the
suppression of gas in group galaxies most likely drives the observed quenching
of the star formation in these systems. Our findings strongly support the
importance of the group environment for galaxy evolution, and have profound
implications for semi-analytic models of galaxy formation, which currently do
not allow for stripping of the cold interstellar medium in galaxy groups.Comment: 36 pages, 16 figures. Accepted for publication in MNRAS. Version with
supplementary material available at
http://www.mpa-garching.mpg.de/GASS/pubs.php . GASS released data can be
found at http://www.mpa-garching.mpg.de/GASS/data.ph
Herschel SPIRE-FTS Observations of Excited CO and [CI] in the Antennae (NGC 4038/39): Warm and Cold Molecular Gas
We present Herschel SPIRE-FTS observations of the Antennae (NGC 4038/39), a
well studied, nearby ( Mpc) ongoing merger between two gas rich spiral
galaxies. We detect 5 CO transitions ( to ), both [CI]
transitions and the [NII] transition across the entire system, which
we supplement with ground based observations of the CO , and
transitions, and Herschel PACS observations of [CII] and [OI].
Using the CO and [CI] transitions, we perform both a LTE analysis of [CI], and
a non-LTE radiative transfer analysis of CO and [CI] using the radiative
transfer code RADEX along with a Bayesian likelihood analysis. We find that
there are two components to the molecular gas: a cold ( K)
and a warm ( K) component. By comparing the warm gas mass
to previously observed values, we determine a CO abundance in the warm gas of
. If the CO abundance is the same in the warm and
cold gas phases, this abundance corresponds to a CO luminosity-to-mass
conversion factor of $\alpha_{CO} \sim 7 \ M_{\odot}{pc^{-2} \ (K \ km \
s^{-1})^{-1}}_263\mu m\sim 0.01 L_{\odot}/M_{\odot}G_0\sim 1000$. Finally, we find
that a combination of turbulent heating, due to the ongoing merger, and
supernova and stellar winds are sufficient to heat the molecular gas.Comment: 50 pages, 15 figures, 8 tables, Accepted for publication in The
Astrophysical Journa
Особенности применения макроэкономического инструментария преодоления кризисных явлений в украинской экономике
Проаналізовано основні макроекономічні показники України у контексті зовнішніх викликів. Приведено досвід країн світу щодо подолання кризових явищ. Визначено перелік заходів, необхідних для стабілізації економіки України та її подальшого зростання.The main macroeconomic indicators of Ukraine have been analyzed in the context of external challenges. The experience of countries in overcoming the crisis have been considered. The list of actions required for the Ukraine’s economy stabilization and its future growth have been defined.Проанализированы основные макроэкономические показатели Украины в контексте внешних вызовов. Приведен опыт стран мира по преодолению кризисных явлений. Определен перечень мероприятий, необходимых для стабилизации экономики Украины и ее дальнейшего роста
Observing Extended Sources with the \Herschel SPIRE Fourier Transform Spectrometer
The Spectral and Photometric Imaging Receiver (SPIRE) on the European Space
Agency's Herschel Space Observatory utilizes a pioneering design for its
imaging spectrometer in the form of a Fourier Transform Spectrometer (FTS). The
standard FTS data reduction and calibration schemes are aimed at objects with
either a spatial extent much larger than the beam size or a source that can be
approximated as a point source within the beam. However, when sources are of
intermediate spatial extent, neither of these calibrations schemes is
appropriate and both the spatial response of the instrument and the source's
light profile must be taken into account and the coupling between them
explicitly derived. To that end, we derive the necessary corrections using an
observed spectrum of a fully extended source with the beam profile and the
source's light profile taken into account. We apply the derived correction to
several observations of planets and compare the corrected spectra with their
spectral models to study the beam coupling efficiency of the instrument in the
case of partially extended sources. We find that we can apply these correction
factors for sources with angular sizes up to \theta_{D} ~ 17". We demonstrate
how the angular size of an extended source can be estimated using the
difference between the sub-spectra observed at the overlap bandwidth of the two
frequency channels in the spectrometer, at 959<\nu<989 GHz. Using this
technique on an observation of Saturn, we estimate a size of 17.2", which is 3%
larger than its true size on the day of observation. Finally, we show the
results of the correction applied on observations of a nearby galaxy, M82, and
the compact core of a Galactic molecular cloud, Sgr B2.Comment: Accepted for publication by A&
Radiative and mechanical feedback into the molecular gas in the Large Magellanic Cloud. I. N159W
We present Herschel SPIRE Fourier Transform Spectrometer (FTS) observations
of N159W, an active star-forming region in the Large Magellanic Cloud (LMC). In
our observations, a number of far-infrared cooling lines including CO(4-3) to
CO(12-11), [CI] 609 and 370 micron, and [NII] 205 micron are clearly detected.
With an aim of investigating the physical conditions and excitation processes
of molecular gas, we first construct CO spectral line energy distributions
(SLEDs) on 10 pc scales by combining the FTS CO transitions with ground-based
low-J CO data and analyze the observed CO SLEDs using non-LTE radiative
transfer models. We find that the CO-traced molecular gas in N159W is warm
(kinetic temperature of 153-754 K) and moderately dense (H2 number density of
(1.1-4.5)e3 cm-3). To assess the impact of the energetic processes in the
interstellar medium on the physical conditions of the CO-emitting gas, we then
compare the observed CO line intensities with the models of photodissociation
regions (PDRs) and shocks. We first constrain the properties of PDRs by
modelling Herschel observations of [OI] 145, [CII] 158, and [CI] 370 micron
fine-structure lines and find that the constrained PDR components emit very
weak CO emission. X-rays and cosmic-rays are also found to provide a negligible
contribution to the CO emission, essentially ruling out ionizing sources
(ultraviolet photons, X-rays, and cosmic-rays) as the dominant heating source
for CO in N159W. On the other hand, mechanical heating by low-velocity C-type
shocks with ~10 km/s appears sufficient enough to reproduce the observed warm
CO.Comment: accepted for publication in A&
Comparison of corneal endothelial mosaic according to the age: the corimmo 3D project
International audienceAim: The human corneal endothelium is a monolayer of flat hexagonal cells. It is a nearly regular hexagonal tessellation during the first years of life, but with age, becomes less regular in shape and size. The aim is to evaluate geometrically the age of an endothelial mosaic.Material and methods: Segmented endothelial mosaics of healthy subjects of different age groups are compared by morphological criteria. The mosaics are studied according to their age group (decades), their age and their location (center or mid-periphery of the cornea). The measures used are: the cell density, the Ripley's L function and the cell area and perimeter density.Results: These measures point out the endothelial cell density decrease, the cell area, perimeter and diameter increase, the cell heterogeneity increase, and the differences between central and mid-peripheral cells increases with age.Conclusion: These measures are able to characterize healthy mosaics
- …
