210 research outputs found

    A charge-coupled device photometric study of south hemispheric contact binary AE Phoenicis

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    The complete charge-coupled device light curves in B, V, R, and I bands of the short-period binary system, AE Phe, are presented. It is found that the light curves of AE Phe belong to typical EW-type light variation. Photometric solutions were derived by using the 2003 version of the Wilson–Devinney code. It showed that AE Phe is a Wsubtype shallow-contact system (f = 14.6%(±0.5%)) with a mass ratio of q = 2.5491(±0.0092). The temperature difference between the two components is 227 K. Analysis of the O − C curve suggests that the period of AE Phe shows a long-term continuous increase at a rate of dP /dt = +6.17(±0.44) × 10−8 days year−1. The longterm period increase, the marginal-contact configuration, and the astrophysical parameters of the binary system, all suggest that it is a shallow-contact binary undergoing a thermal relaxation oscillation evolving into a detached binary.Fil: He, J. J.. Chinese Academy of Sciences; República de ChinaFil: Qian, S. B.. Chinese Academy of Sciences; República de ChinaFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Fariña, Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentin

    Studying star-forming processes at core and clump scales: the case of the young stellar object G29.862-0.0044

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    Massive molecular clumps fragment into cores where star formation takes place, hence star-forming studies should be done at different spatial scales. Using near-IR data obtained with Gemini, data of CH3OCHO and CH3CN from the ALMA database, observations of HCN, HNC, HCO+, and C2H carried out with ASTE, and CO data from public surveys, we perform a deep study of the YSO G29.86-0.004 at core and clump spatial scales. The near-IR emission shows two nebulosities separated by a dark lane, suggesting a typical disk-jets system, but highly asymmetric. They are likely produced by scattered light in cavities carved out by jets on an infalling envelope of material, which also present line emission of H2 and [FeII]. The presence of the complex molecular species observed with ALMA confirms that we are mapping a hot molecular core. The CH3CN emission concentrates at the position of the dark lane and it appears slightly elongated from southwest to northeast in agreement with the inclination of the system as observed at near-IR. The morphology of the CH3OCHO emission is more complex and extends along some filaments and concentrates in knots and clumps, mainly southwards the dark-lane, suggesting that the southern jet is encountering a dense region. The northern jet flows more freely, generating more extended features. This is in agreement with the red-shifted molecular outflow traced by the 12CO J=3-2 line extending towards the northwest and the lack of a blue-shifted outflow. This configuration can be explained by considering that the YSO is located at the furthest edge of the molecular clump along the line of sight, which is consistent with the position of the source in the cloud mapped in the C18O J=3-2 line. The detection of HCN, HNC, HCO+, and C2H allowed us to characterize the dense gas at clump scales, yielding results that are in agreement with the presence of a high-mass protostellar object.Comment: Accepted to be published in A&A (July 13, 2020

    Near-Earth asteroids spectroscopic survey at Isaac Newton Telescope

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    The population of near-Earth asteroids (NEAs) shows a large variety of objects in terms of physical and dynamical properties. They are subject to planetary encounters and to strong solar wind and radiation effects. Their study is also motivated by practical reasons regarding space exploration and long-term probability of impact with the Earth. We aim to spectrally characterize a significant sample of NEAs with sizes in the range of \sim0.25 - 5.5 km (categorized as large), and search for connections between their spectral types and the orbital parameters. Optical spectra of NEAs were obtained using the Isaac Newton Telescope (INT) equipped with the IDS spectrograph. These observations are analyzed using taxonomic classification and by comparison with laboratory spectra of meteorites. A total number of 76 NEAs were observed. We classified 44 of them as Q/S-complex, 16 as B/C-complex, eight as V-types, and another eight belong to the remaining taxonomic classes. Our sample contains 27 asteroids categorized as potentially hazardous and 31 possible targets for space missions including (459872) 2014 EK24, (436724) 2011 UW158, and (67367) 2000 LY27. The spectral data corresponding to (276049) 2002 CE26 and (385186) 1994 AW1 shows the 0.7 μ\mum feature which indicates the presence of hydrated minerals on their surface. We report that Q-types have the lowest perihelia (a median value and absolute deviation of 0.797±0.2440.797\pm0.244 AU) and are systematically larger than the S-type asteroids observed in our sample. We explain these observational evidences by thermal fatigue fragmentation as the main process for the rejuvenation of NEA surfaces. In general terms, the taxonomic distribution of our sample is similar to the previous studies and matches the broad groups of the inner main belt asteroids. Nevertheless, we found a wide diversity of spectra compared to the standard taxonomic types.Comment: Accepted in Astronomy & Astrophysics (A&A

    Therapeutic profile of patients with diabetes treated at the first level of health care

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    Introduction: Diabetes mellitus type 2 (DM2) is a chronic metabolic disease frequently associated with late complications derived from progressive damage several tissues. When patients with DM2 do not respond adequately to non-pharmacological measures, anti-diabetic agents should be indicated to avoid the long-term risk of macro and microvascular complications. Objective: The aim of this study is to evaluate the therapeutic profile for DM2 in the first level of care in the health system in two different countries (Argentina and Paraguay). Methods: This study was an observational descriptive cross-section study. Variables considered were age, sex, date of disease debut, clinical signs of diabetes complications, blood pressure, abdominal circumference, anti-diabetic and anti-hypertensive drugs, and laboratory data. Results: Regarding medication, 30.6% of the patients were treated with biguanides (metformin) and 23.5% with oral hypoglycemic agents; 21.7% with a combination of both anti-diabetic groups; and 3.5% with other therapeutically options (glitazones, meglitinides, SGLT2 inhibitors, and GLP-1 agonist). All the cases of new drug indications were register in Argentina while in Paraguay; all drugs prescribed were considered essential medicines. Conclusion: Diabetes is a frequent disease that causes severe disabilities and death in the affected population. Although it exists several drugs for DM2 treatment, only a few of them follow the rational use of medicines guidelines, while other drugs might be unsafe and certainly more expensive than essential options. Since first level health-care therapeutic strategy plays a major role in avoiding complications from diabetes, countries with low or middle income such as Paraguay or Argentina should do efforts to provide to all patients a rational treatment. This work shows that not in all scenarios, this pattern is true.Fil: Maidana, Gladys Mabel. Universidad Nacional de Asunción; ParaguayFil: Marin, Gustavo Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Samaniego, Lourdes. Universidad Nacional de Asunción; ParaguayFil: Marin, Lupe. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Montiel, Dalva Fariña. Universidad Nacional de Asunción; ParaguayFil: Marin, Gina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas; ArgentinaFil: Vera, Zully. Universidad Nacional de Asunción; ParaguayFil: Lugo Rodríguez, Gladys B.. Universidad Nacional de Asunción; Paragua

    A charge-coupled device photometric study of south hemispheric contact binary ae phoenicis

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    The complete charge-coupled device light curves in B, V, R, and I bands of the short-period binary system, AE Phe, are presented. It is found that the light curves of AE Phe belong to typical EW-type light variation. Photometric solutions were derived by using the 2003 version of the Wilson-Devinney code. It showed that AE Phe is a W-subtype shallow-contact system (f = 14.6%(0.5%)) with a mass ratio of q = 2.5491(0.0092). The temperature difference between the two components is 227 K. Analysis of the O - C curve suggests that the period of AE Phe shows a long-term continuous increase at a rate of dP/dt = +6.17(0.44) × 10-8 days year-1. The long-term period increase, the marginal-contact configuration, and the astrophysical parameters of the binary system, all suggest that it is a shallow-contact binary undergoing a thermal relaxation oscillation evolving into a detached binary.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

    Design and optimization of a child-friendly dispersible tablet containing Isoniazid, Pyrazinamide and Rifampicin for treating Tuberculosis in pediatrics.

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    This is an original manuscript / preprint of an article published by Taylor & Francis in Drug Development and Industrial Pharmacy on 26 Jan 2020, available online: http://www.tandfonline.com/10.1080/03639045.2020.1717516.Objective: Develop a child-friendly Fixed Dose Combination (FDC) water-dispersible tablet for Tuberculosis (TB) treatment, with 50, 150 and 75 mg of isoniazid (INH), pyrazinamide (PZA) and rifampicin (RFP) respectively. This new formulation must contain the lowest possible number of excipients, all accepted for pediatrics, and fulfill all the pharmacopoeia requirements for this type of tablet (friability, disintegration time, fineness of dispersion and content uniformity). Significance: TB is an infectious disease which caused the death of 233,000 children in 2017. At present there is no adequate market dosage form available for children. There is, however, one in a prequalification phase by the World Health Organization but its composition contains some excipients which may not be suitable for pediatrics. Therefore, this new formulation would cover this therapeutic gap. Methods: A factorial design, based on 3 quantitative factors (compression force and concentration of AcDiSol® and Explosol®) at three levels each, was performed to elucidate their influence over disintegration time and friability. In addition, the influence of the press speed on disintegration time, friability, tensile strength, fineness of dispersion and content uniformity over the target tablet was tested. A stability test was done following ICH guideline for accelerated conditions. Results: A water-dispersible tablet was developed according to international recommendations in terms of excipients for pediatrics and meeting Ph. Eur. requirements. In addition, its production has been optimized to be elaborated at maximum eccentric press speed but maintaining quality requirements. Conclusion: A high-quality child-friendly FDC water-dispersible tablet was developed improving the treatment of TB in pediatric

    Supercritical CO2 technology for one-pot foaming and sterilization of polymeric scaffolds for bone regeneration

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    Sterilization is a quite challenging step in the development of novel polymeric scaffolds for regenerative medicine since conventional sterilization techniques may significantly alter their morphological and physicochemical properties. Supercritical (sc) sterilization, i.e. the use of scCO2 as a sterilizing agent, emerges as a promising sterilization method due to the mild operational conditions and excellent penetration capability. In this work, a scCO2 protocol was implemented for the one-pot preparation and sterilization of poly(-caprolactone) (PCL)/poly(lactic-co-glycolic acid) (PLGA) scaffolds. The sterilization conditions were established after screening against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli, Pseudomonas aeruginosa) vegetative bacteria and spores of Bacillus stearothermophilus, Bacillus pumilus and Bacillus atrophaeus. The transition from the sterilization conditions (140 bar, 39 °C) to the compressed foaming (60 bar, 26 °C) was performed through controlled depressurization (3.2 bar/min) and CO2 liquid flow. Controlled depressurization/pressurization cycles were subsequently applied. Using this scCO2 technology toolbox, sterile scaffolds of well-controlled pore architecture were obtained. This sterilization procedure successfully achieved not only SAL-6 against well-known resistant bacteria endospores but also improved the scaffold morphologies compared to standard gamma radiation sterilization proceduresThis work was supported by Xunta de Galicia [ED431F 2016/01, ED431C 2020/17], MCIUN [RTI2018-094131-A-I00], MINECO [SAF2017-83118-R], Consellería de Sanidade, Servizo Galego de Saúde, Axencia de Coñecemento e Saúde (ACIS, CT850A-G), Agencia Estatal de Investigación [AEI] and FEDER funds. V. Santos-Rosales acknowledges to Xunta de Galicia (Consellería de Cultura, Educación e Ordenación Universitaria) for a predoctoral research fellowship [ED481A-2018/014]. C.A. García-González acknowledges to MINECO for a Ramón y Cajal Fellowship [RYC2014-15239]S

    Kinematic Clues to Bar Evolution for Galaxies in the Local Universe: Why the Fastest Rotating Bars are Rotating Most Slowly

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    We have used Spitzer images of a sample of 68 barred spiral galaxies in the local universe to make systematic measurements of bar length and bar strength. We combine these with precise determinations of the corotation radii associated with the bars, taken from our previous study, which used the phase change from radial inflow to radial outflow of gas at corotation, based on high-resolution two-dimensional velocity fields in Hα taken with a Fabry-Pérot spectrometer. After presenting the histograms of the derived bar parameters, we study their dependence on the galaxy morphological type and on the total stellar mass of the host galaxy, and then produce a set of parametric plots. These include the bar pattern speed versus bar length, the pattern speed normalized with the characteristic pattern speed of the outer disk versus the bar strength, and the normalized pattern speed versus R, the ratio of corotation radius to bar length. To provide guidelines for our interpretation, we used recently published simulations, including disk and dark matter halo components. Our most striking conclusion is that bars with values of R < 1.4, previously considered dynamically fast rotators, can be among the slowest rotators both in absolute terms and when their pattern speeds are normalized. The simulations confirm that this is because as the bars are braked, they can grow longer more quickly than the outward drift of the corotation radius. We conclude that dark matter halos have indeed slowed down the rotation of bars on Gyr timescales. © 2017. The American Astronomical Society. All rights reserved.
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