392 research outputs found
A novel 3D technique to study the kinematics of lensed galaxies
We present a 3D Bayesian method to model the kinematics of strongly lensed
galaxies from spatially-resolved emission-line observations. This technique
enables us to simultaneously recover the lens-mass distribution and the source
kinematics directly from the 3D data cube. We have tested this new method with
simulated OSIRIS observations for nine star-forming lensed galaxies with
different kinematic properties. The simulated rotation curves span a range of
shapes which are prototypes of different morphological galaxy types, from dwarf
to massive spiral galaxies. We have found that the median relative accuracy on
the inferred lens and kinematic parameters are at the level of 1 and 2 per
cent, respectively. We have also tested the robustness of the technique against
different inclination angles, signal-to-noise ratios, the presence of warps or
non-circular motions and we have found that the accuracy stays within a few per
cent in most cases. This technique represents a significant step forward with
respect to the methods used until now, as the lens parameters and the
kinematics of the source are derived from the same 3D data. This enables us to
study the possible degeneracies between the two and estimate the uncertainties
on all model parameters consistently.Comment: Accepted for publication in MNRA
Hydrogeology and Hydrogeochemistry of the Lauria Mountains Northern Sector Groundwater Resources (Basilicata, Italy)
In this study, the hydrogeological characterization of the northern sector of the Lauria Mounts carbonate hydrostructure (southern Apennines, Basilicata region) has been carried out and the hydrochemical properties of different collected groundwater samples have been characterized. Several normal springs drain the hydrostructure, some of them characterized by high annual mean discharges. Groundwater samples were collected from different springs; many parameters such as pH, electrical conductivity, and total dissolved solids have been measured, and major (cations and anions) elements and stable isotopes have been analysed following standard test procedures. Other chemical characteristics were derived from the analysed quality parameters. The results elucidate that the main hydrogeochemical processes control the chemical content and assess the quality of the groundwater within the hydrostructure. The analyses highlight that the chemical compositions of groundwater are strongly influenced by the lithology, especially limestones and dolomitic limestones; they explain and confirm the hydrogeological setting of the system. The groundwater system displays light different geochemical signatures. The processes contributing to the concentrations of major ions depend primarily on carbonate dissolution. The analysis, in all studied groundwater samples, shows that the facies groundwater type is Ca–HCO3, bicarbonate is the dominant anion, and calcium is the dominant cation with appreciable magnesium concentrations. To identify the aquifer's recharge areas, the environmental stable isotopes oxygen and hydrogen, deuterium, and 18O were analysed. The unaltered δ18O and δD signatures for the groundwater of the major springs allows identifying the recharge area of these emergencies at elevations ranging from 900 m to 1000 m (a.s.l.), pointing out the presence of deeper flow regime feeding of these springs. The groundwater sample isotopic characteristics of D and 18O suggest that most of the groundwater is recharged directly by infiltration in a high-permeability medium
Dynamical properties of z ∼4.5 dusty star-forming galaxies and their connection with local early-type galaxies
There is a large consensus that gas in high-z galaxies is highly turbulent, because of a combination of stellar feedback processes and gravitational instabilities driven by mergers and gas accretion. In this paper, we present the analysis of a sample of five Dusty Star Forming Galaxies (DSFGs) at 4 ≲ z ≲ 5. Taking advantage of the magnifying power of strong gravitational lensing, we quantified their kinematic and dynamical properties from ALMA observations of their [C ii] emission line. We combined the dynamical measurements obtained for these galaxies with those obtained from previous studies to build the largest sample of z ∼ 4.5 galaxies with high-quality data and sub-kpc spatial resolutions, so far. We found that all galaxies in the sample are dynamically cold, with rotation-to-random motion ratios, V/σ, between 7 and 15. The relation between their velocity dispersions and their star formation rates indicates that stellar feedback is sufficient to sustain the turbulence within these galaxies and no further mechanisms are needed. In addition, we performed a rotation curve decomposition to infer the relative contribution of the baryonic (gas, stars) and dark matter components to the total gravitational potentials. This analysis allowed us to compare the structural properties of the studied DSFGs with those of their descendants, the local early type galaxies. In particular, we found that five out of six galaxies of the sample show the dynamical signature of a bulge, indicating that the spheroidal component is already in place at z ∼ 4.5
Promjenjljivost elektroforetskoga proteinskog profila u “Quarter” konja tijekom natjecanja u obuzdavanju.
The aim of this study was to assess the effect of a reining session on serum total protein and their fractions. In the present study, eight Quarter Horses aged 5-15 years were subjected to reining pattern 5 of the National Reining Horse Association (NRHA). Blood samples were collected from each animal before (T0), immediately after the pattern (T1), after 1h (T2), 2h (T3) and 24h (T4), during the recovery period. On all samples serum total proteins (TP), albumin (Alb), α1-globulins, α2-globulins, β1-globulins, β2-globulins and γ-globulins concentrations, and albumin/globulin ratio (A/G) were assessed. One way repeated measure analysis of variance (ANOVA) showed the statistical significant effect of time on TP and Alb. The application of Bonferroni’s post-hoc comparison showed a statistical significant increase in TP values at T1 compared to T0. Alb concentration increased at T1 compared to T0, T2, T3 and T4. The present study shows how reining exercise affects electrophoretic parameters by increasing TP and Alb levels immediately after exercise. These results provide insight into the reining horse’s physiological response to exercise, allowing better evaluation of the athletic performance of this sport horse.Cilj ovog istraživanja bio je procijeniti učinak natjecanja u obuzdavanju konja na ukupne serumske proteine i na njihove pojedine frakcije. U istraživanju je osam konja Quarter pasmine u dobi od 5 do 15 godina bilo podvrgnuto vježbi 5. stupnja obuzdavanja prema Nacionalnoj udruzi za obuzdavanja konja. Uzorci krvi bili su uzeti od svakog konja prije vježbe (T0), neposredno nakon vježbe (T1), zatim nakon jednog sata (T2), dva sata (T3) i 24 sata (T4) odmora. U svim uzorcima seruma određena je koncentracija ukupnih proteina, albumina (Alb), α1-globulina, α2-globulina, β1-globulina, β2-globulina i γ-globulina te je određen omjer između albumina i globulina (A/G). Jednosmjerna analiza varijance (ANOVA) pokazala je statistički značajan učinak vremena na ukupne proteine i albumin. Primjena Bonferronijeve post-hoc usporedbe pokazala je statistički značajno povećanje vrijednosti ukupnih proteina neposredno nakon vježbe u odnosu na one prije vježbe. Koncentracija albumina bila je povećana neposredno nakon vježbe u usporedbi s koncentracijom prije vježbe te onom jednog sata, dva sata i 24 sata nakon vježbe. Istraživanje pokazuje kako natjecateljsko obuzdavanje konja utječe na elektroforetske pokazatelje povećanjem razine ukupnih proteina i albumina neposredno nakon vježbe. Rezultati pružaju uvid u fiziološki odgovor na vježbu što omogućuje bolju prosudbu atletskih sposobnosti ove pasmine športskog konja
Adaptive POD model reduction for solute transport in heterogeneous porous media
We study the applicability of a model order reduction technique to the solution of transport of passive scalars in homogeneous and heterogeneous porous media. Transport dynamics are modeled through the advection-dispersion equation (ADE) and we employ Proper Orthogonal Decomposition (POD) as a strategy to reduce the computational burden associated with the numerical solution of the ADE. Our application of POD relies on solving the governing ADE for selected times, termed snapshots. The latter are then employed to achieve the desired model order reduction. We introduce a new technique, termed Snapshot Splitting Technique (SST), which allows enriching the dimension of the POD subspace and damping the temporal increase of the modeling error. Coupling SST with a modeling strategy based on alternating over diverse time scales the solution of the full numerical transport model to its reduced counterpart allows extending the benefit of POD over a prolonged temporal window so that the salient features of the process can be captured at a reduced computational cost. The selection of the time scales across which the solution of the full and reduced model are alternated is linked to the Péclet number (Pe), representing the interplay between advective and dispersive processes taking place in the system. Thus, the method is adaptive in space and time across the heterogenous structure of the domain through the combined use of POD and SST and by way of alternating the solution of the full and reduced models. We find that the width of the time scale within which the POD-based reduced model solution provides accurate results tends to increase with decreasing Pe. This suggests that the effects of local-scale dispersive processes facilitate the POD method to capture the salient features of the system dynamics embedded in the selected snapshots. Since the dimension of the reduced model is much lower than that of the full numerical model, the methodology we propose enables one to accurately simulate transport at a markedly reduced computational cost
A novel approach to visibility-space modelling of interferometric gravitational lens observations at high angular resolution
We present a new gravitational lens modelling technique designed to model
high-resolution interferometric observations with large numbers of visibilities
without the need to pre-average the data in time or frequency. We demonstrate
the accuracy of the method using validation tests on mock observations. Using
small data sets with visibilities, we first compare our approach
with the more traditional direct Fourier transform (DFT) implementation and
direct linear solver. Our tests indicate that our source inversion is
indistinguishable from that of the DFT. Our method also infers lens parameters
to within 1 to 2 per cent of both the ground truth and DFT, given sufficiently
high signal-to-noise ratio (SNR). When the SNR is as low as 5, both approaches
lead to errors of several tens of per cent in the lens parameters and a
severely disrupted source structure, indicating that this is an issue related
to the data quality rather than the modelling technique of choice. We then
analyze a large data set with visibilities and a SNR matching real
global Very Long Baseline Interferometry observations of the gravitational lens
system MG J0751+2716. The size of the data is such that it cannot be modelled
with traditional implementations. Using our novel technique, we find that we
can infer the lens parameters and the source brightness distribution,
respectively, with an RMS error of 0.25 and 0.97 per cent relative to the
ground truth.Comment: Submitted to MNRA
Influence of Storage Temperature on Radiochemical Purity of 99mTc-Radiopharmaceuticals
The influence of effective room temperature on the radiochemical purity of
99mTc-radiopharmaceuticals was reported. This study was born from the observation that in
the isolators used for the preparation of the 99mTc-radiopharmaceuticals the temperatures can
be higher than those reported in the commercial illustrative leaflets of the kits. This is due,
in particular, to the small size of the work area, the presence of instruments for heating, the continuous
activation of air filtration, in addition to the fact that the environment of the isolator used for the
99mTc-radiopharmaceuticals preparation and storage is completely isolated and not conditioned.
A total of 244 99mTc-radiopharmaceutical preparations (seven different types) have been tested
and the radiochemical purity was checked at the end of preparation and until the expiry time.
Moreover, we found that the mean temperature into the isolator was significantly higher than 25 C,
the temperature, in general, required for the preparation and storage of 99mTc-radiopharmaceuticals.
Results confirmed the radiochemical stability of radiopharmaceutical products. However, as required
in the field of quality assurance, the impact that different conditions than those required by the
manufacturer on the radiopharmaceuticals quality have to be verified before human administration
An "inherently chiral" 1,1′-bibenzimidazolium additive for enantioselective voltammetry in ionic liquid media
A dialkyl-1,1′-bibenzimidazolium salt, consisting of an atropisomeric dication (i.e. featuring a stereogenic axis and thus "inherently chiral") and an achiral counteranion, is employed as a chiral additive in three commercial ionic liquids, providing successful enantiodiscrimination in voltammetry experiments on screen-printed electrodes (SPEs) with the enantiomers of N,N′-dimethyl-1-ferrocenyl-ethylamine as model chiral probes. Significant differences in redox potentials are observed for the probe enantiomers despite the low concentration (0.01 M) of the chiral additive. The nature of the achiral ionic liquid in which the additive is employed significantly affects the peak potentials and potential differences, but does not alter the enantiomer sequence. Keywords: Chiral electrochemistry and electroanalysis, Ionic liquids, Chiral additives, Inherent chirality, Enantiorecognitio
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