Context. Rotation properties (spin-axis direction and rotation period) and coarse shape models of asteroids can be reconstructed from their disk-integrated brightness when measured from various ...viewing geometries. These physical properties are essential for creating a global picture of structure and dynamical evolution of the main belt. Aims. The number of shape and spin models can be increased not only when new data are available, but also by combining independent data sets and inverting them together. Our aim was to derive new asteroid models by processing readily available photometry. Methods. We used asteroid photometry compiled in the Lowell Observatory photometry database with photometry from the Gaia Data Release 2. Both data sources are available for about 5400 asteroids. In the framework of the Asteroids@home distributed computing project, we applied the light curve inversion method to each asteroid to find its convex shape model and spin state that fits the observed photometry. Results. Due to the limited number of Gaia DR2 data points and poor photometric accuracy of Lowell data, we were able to derive unique models for only ∼1100 asteroids. Nevertheless, 762 of these are new models that significantly enlarge the current database of about 1600 asteroid models. Conclusions. Our results demonstrate the importance of a combined approach to inversion of asteroid photometry. While our models in general agree with those obtained by separate inversion of Lowell and Gaia data, the combined inversion is more robust, model parameters are more constrained, and unique models can be reconstructed in many cases when individual data sets alone are not sufficient.
Context.
The Asteroid Terrestrial-impact Last Alert System (ATLAS) is an all-sky survey primarily aimed at detecting potentially hazardous near-Earth asteroids. Apart from the astrometry of ...asteroids, it also produces their photometric measurements that contain information about asteroid rotation and their shape.
Aims.
To increase the current number of asteroids with a known shape and spin state, we reconstructed asteroid models from ATLAS photometry that was available for approximately 180 000 asteroids observed between 2015 and 2018.
Methods.
We made use of the light-curve inversion method implemented in the Asteroids@home project to process ATLAS photometry for roughly 100 000 asteroids with more than a hundred individual brightness measurements. By scanning the period and pole parameter space, we selected those best-fit models that were, according to our setup, a unique solution for the inverse problem.
Results.
We derived ~2750 unique models, 950 of them were already reconstructed from other data and published. The remaining 1800 models are new. About half of them are only partial models, with an unconstrained pole ecliptic longitude. Together with the shape and spin, we also determined for each modeled asteroid its color index from the cyan and orange filter used by the ATLAS survey. We also show the correlations between the color index, albedo, and slope of the phase-angle function.
Conclusions.
The current analysis is the first inversion of ATLAS asteroid photometry, and it is the first step in exploiting the huge scientific potential that ATLAS photometry has. ATLAS continues to observe, and in the future, this data, together with other independent photometric measurements, can be inverted to produce more refined asteroid models.
Context. Information about shapes and spin states of individual asteroids is important for the study of the whole asteroid population. For asteroids from the main belt, most of the shape models ...available now have been reconstructed from disk-integrated photometry by the lightcurve inversion method. Aims. We want to significantly enlarge the current sample (~350) of available asteroid models. Methods. We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. Results. From the analysis of Lowell photometric data of the first 100 000 numbered asteroids, we derived 328 new models. This almost doubles the number of available models. We tested the reliability of our results by comparing models that were derived from purely Lowell data with those based on dense lightcurves, and we found that the rate of false-positive solutions is very low. We also present updated plots of the distribution of spin obliquities and pole ecliptic longitudes that confirm previous findings about a non-uniform distribution of spin axes. However, the models reconstructed from noisy sparse data are heavily biased towards more elongated bodies with high lightcurve amplitudes. Conclusions. The Lowell Photometric Database is a rich and reliable source of information about the spin states of asteroids. We expect hundreds of other asteroid models for asteroids with numbers larger than 100 000 to be derivable from this data set. More models will be able to be reconstructed when Lowell data are merged with other photometry.
We present the project Asteroids@home that uses distributed computing to solve the time-consuming inverse problem of shape reconstruction of asteroids. The project uses the Berkeley Open ...Infrastructure for Network Computing (BOINC) framework to distribute, collect, and validate small computational units that are solved independently at individual computers of volunteers connected to the project. Shapes, rotational periods, and orientations of the spin axes of asteroids are reconstructed from their disk-integrated photometry by the lightcurve inversion method.
•Asteroids@home is a distributed computing project.•It runs in the framework of Berkeley Open Infrastructure for Network Computing.•Shape models of asteroids are reconstructed from disk-integrated photometry.
The Asteroid Terrestrial-impact Last Alert System (ATLAS) is an all-sky survey primarily aimed at detecting potentially hazardous near-Earth asteroids. Apart from the astrometry of asteroids, it also ...produces their photometric measurements that contain information about asteroid rotation and their shape. To increase the current number of asteroids with a known shape and spin state, we reconstructed asteroid models from ATLAS photometry that was available for approximately 180,000 asteroids observed between 2015 and 2018. We made use of the light-curve inversion method implemented in the Asteroid@home project to process ATLAS photometry for roughly 100,000 asteroids with more than a hundred individual brightness measurements. By scanning the period and pole parameter space, we selected those best-fit models that were, according to our setup, a unique solution for the inverse problem. We derived ~2750 unique models, 950 of them were already reconstructed from other data and published. The remaining 1800 models are new. About half of them are only partial models, with an unconstrained pole ecliptic longitude. Together with the shape and spin, we also determined for each modeled asteroid its color index from the cyan and orange filter used by the ATLAS survey. We also show the correlations between the color index, albedo, and slope of the phase-angle function. The current analysis is the first inversion of ATLAS asteroid photometry, and it is the first step in exploiting the huge scientific potential that ATLAS photometry has. ATLAS continues to observe, and in the future, this data, together with other independent photometric measurements, can be inverted to produce more refined asteroid models.
We use the lightcurve inversion method to derive new shape models and spin states of asteroids from the sparse-in-time photometry compiled in the Lowell Photometric Database. To speed up the ...time-consuming process of scanning the period parameter space through the use of convex shape models, we use the distributed computing project Asteroids@home, running on the Berkeley Open Infrastructure for Network Computing (BOINC) platform. This way, the period-search interval is divided into hundreds of smaller intervals. These intervals are scanned separately by different volunteers and then joined together. We also use an alternative, faster, approach when searching the best-fit period by using a model of triaxial ellipsoid. By this, we can independently confirm periods found with convex models and also find rotation periods for some of those asteroids for which the convex-model approach gives too many solutions. From the analysis of Lowell photometric data of the first 100,000 numbered asteroids, we derived 328 new models. This almost doubles the number of available models. We tested the reliability of our results by comparing models that were derived from purely Lowell data with those based on dense lightcurves, and we found that the rate of false-positive solutions is very low. We also present updated plots of the distribution of spin obliquities and pole ecliptic longitudes that confirm previous findings about a non-uniform distribution of spin axes. However, the models reconstructed from noisy sparse data are heavily biased towards more elongated bodies with high lightcurve amplitudes.
Objetivo: Determinar la asociación entre variables relacionadas con la calidad de la consulta nutricional y la percepción del paciente en el éxito del tratamiento para el control del peso corporal en ...un grupo de mujeres mayores de 20 años, habitantes de la Ciudad Autónoma de Buenos Aires o del Gran Buenos Aires. Metodología: Diseño observacional, transversal de correlación. Muestreo aleatorio simple de 97 mujeres que concurrieron por lo menos una vez a una consulta nutricional llevada a cabo por un Licenciado en Nutrición. Se realizó encuesta estructurada y voluntaria analizando como variable dependiente la percepción del éxito del tratamiento nutricional y como variables independientes tres variables relacionadas con la calidad de la atención como la escucha del profesional (buena, regular o mala), indicaciones adecuadas a gustos, hábitos y tolerancias digestivas y tipo de material entregado en la consulta. El análisis estadístico se realizó con SPSS 15,0 aplicando diferencia de proporciones y OR con valor p<0,05. Resultados: Del total de la muestra estudiada el 61,9% percibió como exitoso a su último tratamiento para el control del peso corporal. Para la mayoría el ámbito físico donde se desarrolló la consulta fue adecuado (95,9%), siendo suficiente el tiempo destinado a la misma (89,7%), con buena escucha llevada a cabo por el profesional (75,3%). La percepción del éxito fue asociada significativamente con una buena escucha del profesional en la consulta (p: 0,0001) y con el manejo de indicaciones adecuadas a los gustos y hábitos de las pacientes (p: 0,002). No se observo asociación entre las indicaciones adecuadas a la tolerancia digestiva y el tipo de material empleado con la percepción de éxito en la consulta nutricional. Conclusiones: La percepción del éxito en el tratamiento nutricional fue asociada significativamente con una buena escucha por parte del profesional en la consulta e indicaciones adecuadas en cuanto a sus gustos y hábitos alimentarios.
Structurally diverse zinc( ii ) complexes with tripodal tetradentate phenolic-amines of variable substituents in the phenol and amine moieties were synthesized and thoroughly characterized. The two ...dinuclear Zn 2 (L 1 ) 2 (ClO 4 ) 2 ·MeOH (1), Zn 2 (L 2 ) 2 (ClO 4 ) 2 (2), and four mononuclear Zn(L 3 )(H 2 O)·MeOH (3), Zn(L 4 ) (4), Zn(L 5 ) (5) and Zn(L 6 ) (6) complexes revealed distorted octahedral, trigonal–bipyramidal or tetrahedral geometries. The free HL1 and H2L3–6 ligands, and complexes 1–6 were evaluated for in vitro cytotoxicity against human cancer cell lines (A2780, A2780R, PC-3 and 22Rv1) and normal healthy MRC-5 cells. Overall results revealed high-to-moderate cytotoxicity (with the best IC 50 values for complex 6 ranging from 2.4 to 4.5 μM), which is however, significantly higher than that of the reference drug cisplatin. The moderately active complexes 1–4 showed considerable selectivity on A2780 cells (IC 50 ≈ 16.3–19.5 μM) over MRC-5 ones (with IC 50 >50 μM for 1, 2 and 4, and with IC 50 >25 μM for 3). The complexes 1, 2, and 6 and the ligand H2L6 were chosen for subsequent deeper biological evaluations. Their time-resolved cellular uptake and other cellular effects in A2780 cells were studied, such as cell cycle profile, intracellular ROS production, induction of apoptosis and activation of caspases 3/7. Complexes 1 and 2 caused significant G0/G1 cell cycle arrest in A2780 cells and antioxidant effects at normal conditions. They showed only limited effects on cellular processes connected with cytotoxicity, i.e. induction of apoptosis, depletion of mitochondrial membrane potential, and autophagy. These findings can be at least partly attributed to the low ability of the complexes to enter the A2780 cells and the depression of metabolic activity of the target cancer cells.
Two cationic Cu2(L1-2)2(ClO4)2 (1, 2), and four neutral doubly bridged-phenoxido-copper(II) complexes Cu2(L3-4)2 (3, 4) and Cu2(L5-6)2(H2O)‧2H2O (5, 6) as well as 1D polymeric catena-Cu(L7) (7), ...where HL1-2 and H2L3-7 represent tripodal tetradentate pyridyl or aliphatic-amino groups based 2,4-disubstituted phenolates, were synthesized and thoroughly characterized by various spectroscopic methods and single crystal X-ray analysis. The molecular structures of the complexes exhibited diverse geometrical environments around the central Cu(II) atoms. The in vitro antiproliferative activity of the isolated complexes and selected parent free ligands were screened against some human cancer cell lines (A2780, A2780R, PC-3, 22Rv1, MCF-7). The most promising cytotoxicity against cancer cells were obtained for 1–6, while complex 6 was found as the best performing as compared to the reference drug cisplatin. The cytotoxicity study of complex 6 was therefore extended to wider variety of cancer cell lines (HOS, A549, PANC-1, CaCo2, HeLa) and results revealed its significant cytotoxicity on all investigated human cancer cells. The cell uptake study showed that cytotoxicity of 6 (3 μM concentration and 24 h of incubation) against A2780 cells was almost independent from the intracellular levels of copper. The effect of complexes 4, 6 and 7 on cell cycle of A2780 cells indicates that the mechanism of action in these complexes is not only different from that of cisplatin but also different among them. Complex 7 was able to induce apoptosis in A2780 cells, while complexes 4 and 6 did not and on the other hand, they showed considerable effect on autophagy induction and there are some clues that these complexes were able to induce cuproptosis in A2780 cells.
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•Six dinuclear doubly bridged phenoxido-Cu(II) (1–6) were structurally characterized.•The in vitro anticancer activity of the complexes was tested against human cancer cell lines.•Complex 6 revealed very high cytotoxicity against the 9 tested cancer cell lines and complex 7 the least activity•Complexes 1–6 showed high cytotoxicity against cancer cell lines A2780 and A2780R and the pyridyl complexes 1 - 3 revealed significant selectivity,•The cell deaths, autophagy and ROS induction of selected compounds were tested against cancer cells A2780.
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