682 research outputs found
Evaluation of composts and liming materials in the phytostabilization of a mine soil using perennial ryegrass
A microcosm experiment was carried out to evaluate the effects of municipal solid waste
compost (MSWC) or garden waste compost (GWC), and liming materials in the rehabilitation
of a soil affected by mining activities, and to study the use of perennial ryegrass (Lolium
perenne L.) for phystostabilization. The performance of the amendments was assessed by
soil chemical parameters, total and bioavailable metals (Cu, Pb and Zn), soil enzymatic
activities, and plant relative growth and mineral composition. In general, both composts
corrected soil acidity and increased the total organic matter content of the soil, although
with a better performance in the case of MSWC, especially when considering total N and
available P and K levels in the amended soil. The application of both composts and liming
materials led to a decrease in the mobile fractions of Cu, Pb and Zn, but mobilisable fractions
of Cu and Zn increased with MSWC application. Plant biomass increased more than three
times in the presence of 50 Mg MSWC ha−1 and with the combined use of 25 or 50 Mg MSWC
ha−1 and CaO, but no significant differences were observed when GWC was applied. Plant
tissue analysis showed that the treatments did not significantly reduce Cu, Pb and Zn
uptake by the plant. Dehydrogenase, and the enzymes related to the N-cycle, urease and
protease, had increased activities with increasing MSWC application rate. Conversely, the
enzymatic activities of both enzymes related to the C-cycle, cellulase and β-glucosidase,
were only positively affected by GWC application, a compost obtained from raw materials
rich in C. Principal component analyses evidenced this clear separation between the effect
of MSWC on soil enzymes related to the N-cycle and of GWC on soil enzymes related to the
C-cycle. This study indicates that MSWC (50 Mg ha−1, limed or unlimed) can be used
successfully in the remediation of a highly acidic metal-contaminated soil, allowing the
establishment of perennial ryegrass
Organic residues as immobilizing agents in aided phytostabilization: (I) Effects on soil chemical characteristics
A greenhouse experiment was conducted to evaluate the effect of three different organic residues, sewage
sludge (SS), municipal solid waste compost (MSWC), and garden waste compost (GWC), as immobilizing
agents in aided phytostabilization of a highly acidic metal-contaminated soil, affected by mining
activities, using perennial ryegrass (Lolium perenne L.). The organic residues were applied at 25, 50 and
100 Mg ha 1 (dry weight basis), and their effects on soil chemical characteristics and on relative plant
growth and metal concentrations were assessed. All the organic residues tested immobilized Cu, Pb
and Zn, decreasing their mobile fractions. This was corroborated by negative correlations obtained
between mobile Cu, Pb and Zn and other soil chemical characteristics, which rose as a consequence of
the amendments applied (i.e., pH, electrical conductivity, organic matter, nitrogen content, available P
and available K), and by the multivariate exploratory techniques performed that showed an inverse correlation
between these groups of variables. The greatest increase in ryegrass relative growth (more than
three times) was obtained in the presence of 50 Mg MSWC ha 1, followed by SS at the same application
dosage. GWC did not contribute to an increase in shoot growth, due to its small capacity to correct soil
acidity and to supply essential macronutrients (N, P, K). No extractant was able of demonstrating by a
linear correlation the uptake of Cu, Pb and Zn by ryegrass. This plant was therefore not a good ‘‘indicator”
of Cu, Pb and Zn availability in the soil. The results obtained in this study suggest that ryegrass can be
used in aided phytostabilization for this type of mine contaminated soils and that MSWC, and to a minor
extent SS, applied at 50 Mg ha 1, were effective in the in situ immobilization of metals, improving soil
chemical properties and leading to a large increase in plant biomas
Evaluation of tests to assess the quality of mine-contaminated soils
An acid metal-contaminated soil from the
Aljustrel mining area (a pyrite mine located in SW
Portugal in the Iberian Pyrite Belt) was subjected to
chemical characterisation and total metal quantiWcation
(Cd, Cr, Cu, Ni, Pb and Zn). Water-soluble metals
were determined and a sequential extraction
procedure was used to investigate metal speciation.
Two bioavailable metal fractions were determined: a
mobile fraction and a mobilisable fraction. Soil ecotoxicity
was studied using a battery of bioassays:
plant growth test and seed germination with cress
(Lepidium sativum L.), earthworm (Eisenia fetida)
mortality, E. fetida avoidance behaviour, luminescent
inhibition of Vibrio Wscheri and Daphnia magna
immobilisation. Although the total content of Cu, Zn and Pb in the soil was large (362, 245 and 1,250 mg/
kg dry matter, respectively), these metals were mostly
structurally bound (87% for Cu, 81% for Zn and 89%
for Pb) and, therefore, scarcely bioavailable. Nonetheless,
the D. magna immobilization test using soil
leachate showed an EC50 (48 h) of 36.3% (v/v), and
the luminescent inhibition of V. Wscheri presented an
EC20 (15 min) of 45.2% and an EC20 (30 min) of
10.7% (v/v), suggesting a considerable toxic eVect. In
the direct exposure bioassays, E. fetida avoided the
mine soil at the highest concentrations (50%, 75%
and 100% v/v). At the same soil concentrations, cress
showed negligible growth. The results suggest the
need to use a battery of toxicity tests, in conjunction
with chemical methods, in order to assess the quality
of mine-contaminated soils correctly
International Union of Basic and Clinical Pharmacology. CXII: adenosine receptors: a further update
Our previous International Union of Basic and Clinical Pharmacology report on the nomenclature and classification of adenosine receptors (2011) contained a number of emerging developments with respect to this G protein-coupled receptor subfamily, including protein structure, protein oligomerization, protein diversity, and allosteric modulation by small molecules. Since then, a wealth of new data and results has been added, allowing us to explore novel concepts such as target binding kinetics and biased signaling of adenosine receptors, to examine a multitude of receptor structures and novel ligands, to gauge new pharmacology, and to evaluate clinical trials with adenosine receptor ligands. This review should therefore be considered a further update of our previous reports from 2001 and 2011.Significance Statement-Adenosine receptors (ARs) are of continuing interest for future treatment of chronic and acute disease conditions, including inflammatory diseases, neurodegenerative afflictions, and cancer. The design of AR agonists ("biased" or not) and antagonists is largely structure based now, thanks to the tremendous progress in AR structural biology. The A2A and A2BAR appear to modulate the immune response in tumor biology. Many clinical trials for this indication are ongoing, whereas an A2AAR antagonist (istradefylline) has been approved as an anti-Parkinson agent.Medicinal Chemistr
Frictional drag between non-equilibrium charged gases
The frictional drag force between separated but coupled two-dimensional
electron gases of different temperatures is studied using the non-equilibrium
Green function method based on the separation of center-of-mass and relative
dynamics of electrons. As the mechanisms of producing the frictional force we
include the direct Coulomb interaction, the interaction mediated via virtual
and real TA and LA phonons, optic phonons, plasmons, and TA and LA
phonon-electron collective modes. We found that, when the distance between the
two electron gases is large, and at intermediate temperature where plasmons and
collective modes play the most important role in the frictional drag, the
possibility of having a temperature difference between two subsystems modifies
greatly the transresistivity.Comment: 8figure
The brain decade in debate: II. Panic or anxiety? From animal models to a neurobiological basis
This article is a transcription of an electronic symposium sponsored by the Brazilian Society of Neuroscience and Behavior (SBNeC). Invited researchers from the European Union, North America and Brazil discussed two issues on anxiety, namely whether panic is a very intense anxiety or something else, and what aspects of clinical anxiety are reproduced by animal models. Concerning the first issue, most participants agreed that generalized anxiety and panic disorder are different on the basis of clinical manifestations, drug response and animal models. Also, underlying brain structures, neurotransmitter modulation and hormonal changes seem to involve important differences. It is also common knowledge that existing animal models generate different types of fear/anxiety. A challenge for future research is to establish a good correlation between animal models and nosological classification.Universidade Federal do Paraná Departamento de Farmacologia Laboratório de Fisiologia e Farmacologia do Sistema Nervoso CentralUniversity of Hawaii Department of NeurobiologyUniversity of Hawaii Department of PsychologyUniversidade de São Paulo Faculdade de Filosofia Ciências e Letras de Ribeirão Preto Departamento de PsicobiologiaUniversidade de São Paulo Faculdade de Medicina de Ribeirão Preto Departamento de FisiologiaUniversidade de São Paulo Faculdade de Medicina de Ribeirão Preto Departamento de NeuropsiquiatriaUniversidade Federal de Santa Catarina Departamento de FarmacologiaCentral Nervous System Research Department Sanofi SynthelaboAston University Institute of Pharmaceutical SciencesHoffmann-La Roche Ltd.Universidade Federal de São Paulo (UNIFESP) Escola Paulista de Medicina Departamento de PsicologiaUniversity of Leeds Department of Psychology Ethopharmacology LaboratoryUniversidade Federal do Espírito Santo Centro de Biomedicina Departamento de Ciências FisiológicasUNIFESP, EPM, Depto. de PsicologiaSciEL
An ALMA Survey of the SCUBA-2 Cosmology Legacy Survey UKIDSS/UDS Field: The Far-infrared/Radio Correlation for High-redshift Dusty Star-forming Galaxies
We study the radio properties of 706 submillimeter galaxies (SMGs) selected at 870 μm with the Atacama Large Millimeter Array from the SCUBA-2 Cosmology Legacy Survey map of the Ultra Deep Survey field. We detect 273 SMGs at >4σ in deep Karl G. Jansky Very Large Array 1.4 GHz observations, of which a subset of 45 SMGs are additionally detected in 610 MHz Giant Metre-Wave Radio Telescope imaging. We quantify the far-infrared/radio correlation (FIRRC) through parameter q IR, defined as the logarithmic ratio of the far-infrared and radio luminosity, and include the radio-undetected SMGs through a stacking analysis. We determine a median q IR = 2.20 ± 0.03 for the full sample, independent of redshift, which places these z ~ 2.5 dusty star-forming galaxies 0.44 ± 0.04 dex below the local correlation for both normal star-forming galaxies and local ultra-luminous infrared galaxies (ULIRGs). Both the lack of redshift evolution and the offset from the local correlation are likely the result of the different physical conditions in high-redshift starburst galaxies, compared to local star-forming sources. We explain the offset through a combination of strong magnetic fields (B gsim 0.2 mG), high interstellar medium (ISM) densities and additional radio emission generated by secondary cosmic rays. While local ULIRGs are likely to have similar magnetic field strengths, we find that their compactness, in combination with a higher ISM density compared to SMGs, naturally explains why local and high-redshift dusty star-forming galaxies follow a different FIRRC. Overall, our findings paint SMGs as a homogeneous population of galaxies, as illustrated by their tight and nonevolving far-infrared/radio correlation
General Requirements on Matter Power Spectrum Predictions for Cosmology with Weak Lensing Tomography
Forthcoming projects such as DES, LSST, WFIRST, and Euclid aim to measure
weak lensing shear correlations with unprecedented precision, constraining the
dark energy equation of state at the percent level. Reliance on
photometrically-determined redshifts constitutes a major source of uncertainty
for these surveys. Additionally, interpreting the weak lensing signal requires
a detailed understanding of the nonlinear physics of gravitational collapse. We
present a new analysis of the stringent calibration requirements for weak
lensing analyses of future imaging surveys that addresses both photo-z
uncertainty and errors in the calibration of the matter power spectrum. We find
that when photo-z uncertainty is taken into account the requirements on the
level of precision in the prediction for the matter power spectrum are more
stringent than previously thought. Including degree-scale galaxy clustering
statistics in a joint analysis with weak lensing not only strengthens the
survey's constraining power by ~20%, but can also have a profound impact on the
calibration demands, decreasing the degradation in dark energy constraints with
matter power spectrum uncertainty by a factor of 2-5. Similarly, using galaxy
clustering information significantly relaxes the demands on photo-z
calibration. We compare these calibration requirements to the contemporary
state-of-the-art in photometric redshift estimation and predictions of the
power spectrum and suggest strategies to utilize forthcoming data optimally.Comment: 3 new figures; new section added on multipole-dependence of
calibration requirements; references added; version accepted by JCA
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