3,827 research outputs found
Golden gravitational lensing systems from the Sloan Lens ACS Survey. II. SDSS J1430+4105: A precise inner total mass profile from lensing alone
We study the SLACS strong lensing system SDSSJ1430+4105 at z=0.285. The
lensed source (z=0.575) of this system has a complex morphology with several
subcomponents. Its subcomponents span a radial range from 4 to 10kpc in the
lens plane. Therefore we can constrain the slope of the total projected mass
profile around the Einstein radius (R_E) from lensing alone. We measure a
density profile that is slightly but not significantly shallower than
isothermal at R_E. We decompose the mass of the lensing galaxy into a de
Vaucouleurs (deV) component to trace the stars and an additional dark
component. The spread of multiple image components over a large radial range
also allows us to determine the amplitude of the deV and dark matter components
separately. We get a mass to light ratio of M_deV/L_B~5.5\pm1.5M/L_sun,B and a
dark matter fraction within R_E of ~20 to 40%. Modelling the star formation
history assuming composite stellar populations at solar metallicity to the
galaxy's photometry yields a mass to light ratio of
M_star,salp/L_B~4.0_{-1.3}^{+0.6}M/L_sun,B and
M_star,chab/L_B~2.3_{-0.8}^{+0.3}M/L_sun,B for Salpeter and Chabrier IMFs,
respectively. Hence, the mass to light ratio derived from lensing is more
Salpeter-like, in agreement with results for massive Coma galaxies and other
nearby massive early type galaxies. We examine the consequences of the galaxy
group in which the lensing galaxy is embedded, showing that it has little
influence on the mass to light ratio obtained for the deV component of the
lensing galaxy. Finally, we decompose the projected, azimuthally averaged 2D
density distribution of the deV and dark matter component of the lensing signal
into spherically averaged 3D density profiles. We can show that the 3D dark and
luminous matter density within R_E~0.6R_eff of this SLACS galaxy is similar to
the values of Coma galaxies with the same velocity dispersions.Comment: 24 pages, 21 figures, 11 tables, accepted for publication by MNRA
Ametryn removal by Metarhizium brunneum: Biodegradation pathway proposal and metabolic background revealed
Ametryn is a representative of a class of s-triazine herbicides absorbed by plant roots and leaves and characterized as a photosynthesis inhibitor. It is still in use in some countries in the farming of pineapples, soybean, corn, cotton, sugar cane or bananas; however, due to the adverse effects of s-triazine herbicides on living organisms use of these pesticides in the European Union has been banned. In the current study, we characterized the biodegradation of ametryn (100 mg L-1) by entomopathogenic fungal cosmopolite Metarhizium brunneum. Ametryn significantly inhibited the growth and glucose uptake in fungal cultures. The concentration of the xenobiotic drops to 87.75 mg L-1 at the end of culturing and the biodegradation process leads to formation of four metabolites: 2-hydroxy atrazine, ethyl hydroxylated ametryn, S-demethylated ametryn and deethylametryn. Inhibited growth is reflected in the metabolomics data, where significant differences in concentrations of L-proline, gamma-aminobutyric acid, L-glutamine, 4-hydroxyproline, L-glutamic acid, ornithine and L-arginine were observed in the presence of the xenobiotic when compared to control cultures. The metabolomics data demonstrated that the presence of ametryn in the fungal culture induced oxidative stress and serious disruptions of the carbon and nitrogen metabolism. Our results provide deeper insights into the microorganism strategy for xenobiotic biodegradation which may result in future enhancements to ametryn removal by the tested strain.National Science Center, Poland (Project No. 2015/19/B/NZ9/00167
Habitat fragmentation and the future structure of tree assemblages in a fragmented Atlantic forest landscape
The biodiversity value of human-modified landscapes has become a central question in the tropical forest conservation biology, yet the degree to which plant populations and communities are restructured in response to environmental change remains unclear. Here, we address tree species density in a fragmented Atlantic forest landscape to test the hypothesis that tree assemblages inhabiting edge-dominated forest habitats approach typical conditions of early successional systems. Seedlings and adults from 141 tree species were sampled across 39 0.1-ha plots: 19 in small fragments (55 % of all tree species exhibiting higher densities in small fragments than in mature forest, particularly pioneers (>60 % of all species). Seedlings and adults of these proliferating species differed from species exhibiting population declines in terms of wood density and seed size, respectively. Additionally, pioneers were more abundant than shade-tolerant species, as were hardwood species in the case of seedlings. Tree species showing highest population increases consisted largely of long-lived, light-demanding canopy species bearing soft or hardwood and small-to-medium-sized seeds. Tree assemblage structure also differed in terms of forest habitats with small forest fragments supporting few rare species, whereas the most rapidly proliferating species were much more widespread and abundant in fragments. However, 60 % of all adult pioneer species recorded in small fragments were not recorded as seedlings in this habitat type, although both seedling and adult assemblages were dominated by pioneer species. Edge-dominated tree assemblages are likely to experience long-term shifts toward greater dominance of long-lived, pioneer canopy species
Glucose metabolite glyoxal induces senescence in telomerase-immortalized human mesenchymal stem cells
Gap width modification on fully screen-printed coplanar Zn|MnO2 batteries
Fully printed primary zinc-manganese dioxide (Zn|MnO2) batteries in coplanar configuration were fabricated by sequential screen printing. While electrode dimensions and transferred active masses were kept at constant levels, electrode separating gaps were incrementally enlarged from 1 mm to 5 mm. Calendering of solely zinc anodes increased interparticle contact of active material within the electrodes while the porosity of manganese dioxide based electrodes was maintained by non-calendering. Chronopotentiometry revealed areal capacities for coplanar batteries up to 2.8 mAh cmâ2. Galvanostatic electrochemical impedance spectroscopy measurements and short circuit measurements were used to comprehensively characterise the effect of gap width extension on bulk electrolyte resistance and charge transfer resistance values. Linear relationships between nominal gap widths, short circuit currents and internal resistances were evidenced, but showed only minor impact on actual discharge capacities. The findings contradict previous assumptions to minimise gap widths of printed coplanar batteries to a sub-millimetre range in order to retain useful discharge capacities. The results presented in this study may facilitate process transfer of printed batteries to an industrial environment
Connections between Alternative Transcription and Alternative Splicing in Mammals
The majority of mammalian genes produce multiple transcripts resulting from alternative splicing (AS) and/or alternative transcription initiation (ATI) and alternative transcription termination (ATT). Comparative analysis of the number of alternative nucleotides, isoforms, and introns per locus in genes with different types of alternative events suggests that ATI and ATT contribute to the diversity of human and mouse transcriptome even more than AS. There is a strong negative correlation between AS and ATI in 5âČ untranslated regions (UTRs) and AS in coding sequences (CDSs) but an even stronger positive correlation between AS in CDSs and ATT in 3âČ UTRs. These observations could reflect preferential regulation of distinct, large groups of genes by different mechanisms: 1) regulation at the level of transcription initiation and initiation of translation resulting from ATI and AS in 5âČ UTRs and 2) posttranslational regulation by different protein isoforms. The tight linkage between AS in CDSs and ATT in 3âČ UTRs suggests that variability of 3âČ UTRs mediates differential translational regulation of alternative protein forms. Together, the results imply coordinate evolution of AS and alternative transcription, processes that occur concomitantly within gene expression factories
PropellerâLike NanorodâUpconversion Nanoparticle Assemblies with Intense Chiroptical Activity and Luminescence Enhancement in Aqueous Phase
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/133596/1/adma201601261-sup-0001-S1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133596/2/adma201601261_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/133596/3/adma201601261.pd
The stellar and sub-stellar IMF of simple and composite populations
The current knowledge on the stellar IMF is documented. It appears to become
top-heavy when the star-formation rate density surpasses about 0.1Msun/(yr
pc^3) on a pc scale and it may become increasingly bottom-heavy with increasing
metallicity and in increasingly massive early-type galaxies. It declines quite
steeply below about 0.07Msun with brown dwarfs (BDs) and very low mass stars
having their own IMF. The most massive star of mass mmax formed in an embedded
cluster with stellar mass Mecl correlates strongly with Mecl being a result of
gravitation-driven but resource-limited growth and fragmentation induced
starvation. There is no convincing evidence whatsoever that massive stars do
form in isolation. Various methods of discretising a stellar population are
introduced: optimal sampling leads to a mass distribution that perfectly
represents the exact form of the desired IMF and the mmax-to-Mecl relation,
while random sampling results in statistical variations of the shape of the
IMF. The observed mmax-to-Mecl correlation and the small spread of IMF
power-law indices together suggest that optimally sampling the IMF may be the
more realistic description of star formation than random sampling from a
universal IMF with a constant upper mass limit. Composite populations on galaxy
scales, which are formed from many pc scale star formation events, need to be
described by the integrated galactic IMF. This IGIMF varies systematically from
top-light to top-heavy in dependence of galaxy type and star formation rate,
with dramatic implications for theories of galaxy formation and evolution.Comment: 167 pages, 37 figures, 3 tables, published in Stellar Systems and
Galactic Structure, Vol.5, Springer. This revised version is consistent with
the published version and includes additional references and minor additions
to the text as well as a recomputed Table 1. ISBN 978-90-481-8817-
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
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