15 research outputs found
Postillati epicurei di Ettore Bignone
No full textSome of the books of Ettore Bignone's library once owned by the
Italian Latinist Luigi Alfonsi eventually came into the possession of
the author of the present article. Bignone was a careful reader and
added many remarks in the margins of his books; among these, several
notes on Epicurean problems are worth studying. This because Bignone
criticises well known scholars such as Constant Martha, Alfred Ernout,
and Carlo Pascal, explains difficult passages and suggests alternative
interpretations. Some of these notes have the length of a short
article, but even his very brief comments are often of high scholarly
interest
Safety and efficacy of secukinumab treatment in a patient with ankylosing spondylitis and concomitant multiple sclerosis
No full textnot availabl
T2-mapping of the sacroiliac joints at 1.5 Tesla : A feasibility and reproducibility study
No full textObjective: To evaluate the reproducibility of T2 relaxation time measurements of the sacroiliac joints at 1.5 T. Materials and methods: Healthy volunteers underwent an oblique axial multislice multiecho spin-echo sequence of the sacroiliac joints at 1.5 T. Regions of interest were manually drawn using a dedicated software by two musculoskeletal radiologists to include the cartilaginous part of the sacroiliac joints. A senior radiologist performed the measurement twice, while a resident measured once. Intra- and inter-observer reproducibility was tested using the Bland-Altman method. Association between sex and T2 relaxation times was tested using the Mann-Whitney U test. Correlation between T2 relaxation times and body mass index (BMI) was tested using the Spearman’s rho. Results: Eighty sacroiliac joints of 40 subjects (mean age: 28 ± 4.8 years, range: 20–43; mean BMI: 23.3 ± 3.1, range: 18.9–30) were imaged. The mean T2 values obtained by the senior radiologist in the first series of measurements were 42 ± 4.4 ms, whereas in the second series were 40.7 ± 4.5 ms. The mean T2 values obtained by the radiology resident were 41.1 ± 4.2 ms. Intra-observer reproducibility was 88% (coefficient of repeatability = 3.8; bias = 1.28; p <.001), while inter-observer reproducibility was 86% (4.7; −.88; p <.001). There was significant association between sex and T2 relaxation times (p =.024) and significant inverse correlation between T2 relaxation times and BMI (r = −.340, p =.002). Conclusion: The assessment of T2 relaxation time measurements of sacroiliac joints seems to be highly reproducible at 1.5 T. Further studies could investigate the potential clinical application of this tool in the sacroiliac joints
Effects of mergers on non-parametric morphologies
No full textWe study the effects of mergers on non-parametric morphologies of galaxies. We compute the Gini index, M20, asymmetry and concentration statistics for z = 0 galaxies in the Illustris simulation and compare non-parametric morphologies of major mergers, minor merges, close pairs, distant pairs and unperturbed galaxies. We determine the effectiveness of observational methods based on these statistics to select merging galaxies.Fil: Bignone, Lucas Axel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Tissera, Patricia Beatriz. Universidad Andrés Bello; Chile. Instituto Milenio de Astrofísica; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Sillero Ros, Guillermo Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Pedrosa, Susana Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Pellizza González, Leonardo Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin
T2 Mapping of the Sacroiliac Joints in Patients with Axial Spondyloarthritis
No full textPurpose: To test whether T2 mapping of the sacro-iliac joints (SIJs) might help identifying patients with spondyloarthritis.
Method: This study included 20 biologic-naive patients with axial spondyloarthritis (10 females; mean age: 38 ± 9years; range, 19-47) and 27 controls (16 males; mean age = 39 ± 13years; range = 28-71) who prospectively underwent SIJs MRI at 1.5 T, including a multislice multiecho spin-echo sequence. Standard MRIs were reviewed to assess the SIJs according to the Assessment of SpondyloArthritis International Society (ASAS) criteria and SPondyloArthritis Research Consortium of Canada (SPARCC) MRI index. T2 maps obtained from multiecho sequences were used to draw regions of interests in the cartilaginous part of the SIJs. Disease activity was assessed using BASDAI questionnaire. Bland-Altman method, ROC curve analysis, Chi square, Mann-Whitney U, Pearson's and Spearman's correlation coefficient were used for data analysis.
Results: According to ASAS criteria, MRI was positive for sacroiliitis in 5/20 patients (25 %). Inter-observer reproducibility of T2 values was 87 % (coefficient of repeatability = 7.0; bias = 0.49; p < .001). Mean T2 values of patients (58.5 ± 4.4 ms, range: 52.6-68.2 ms) were significantly higher (p < .001) than those of controls (44.1 ± 6.6 ms, range: 33.6-67.2 ms). A T2 value of 52.51 ms yielded 100 % sensitivity and 91.7 % specificity to differentiate patients from controls. No statistically significant association/correlation was found between T2 values and BASDAI (r=-.026, p = .827), disease duration (r = .024, p = .871), SPARCC (r=-.004, p = .981), ASAS criteria (p = .476), HLA-B27-positivity (p = .139), age (r=-.2.53, p = .891), and gender (p = .404).
Conclusions: T2 relaxation times of the SIJs were significantly higher in patients than in healthy controls, making this tool potentially helpful to early identify patients with spondyloarthritis
Satellite galaxies in groups in the CIELO Project I: Gas removal from galaxies and its re-distribution in the intragroup medium
No full textWe study the impact of the environment on galaxies as they fall in and orbit in the potential well of a Local Group (LG) analogue, following them with high cadence. The analysis is performed on eight disc satellite galaxies from the CIELO suite of hydrodynamical simulations. All galaxies have stellar masses within the range [10 8.1 -109.56 ] M⊙h-1. We measure tidal torques, ram pressure, and specific star formation rates (sSFRs) as a function of time, and correlate them with the amount of gas lost by satellites along their orbits. Stronger removal episodes occur when the disc plane is oriented perpendicular to the direction of motion. More than one peripassage is required to significantly modify the orientations of the discs with respect to the orbital plane. The gas removed during the interaction with the central galaxies may also be found opposite to the direction of motion, depending on the orbital configuration. Satellites are not totally quenched when the galaxies reach their first peripassage and continue forming about 10 per cent of the final stellar mass after this event. The fraction of removed gas is found to be the product of the joint action of tidal torque and ram pressure, which can also trigger new star formation activity and subsequent supernova feedback.Fil: Rodríguez Moncada, Silvio Ribamar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Padilla, Nelson David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Tissera, P.. Pontificia Universidad Católica de Chile; ChileFil: Bignone, Lucas Axel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Dominguez Tenreiro, Rosa. Pontificia Universidad Católica de Chile; ChileFil: Gonzalez, R.. Pontificia Universidad Católica de Chile; ChileFil: Pedrosa, Susana Elizabeth. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin
Diffusion-Weighted Imaging in Oncology: An Update
No full textTo date, diffusion weighted imaging (DWI) is included in routine magnetic resonance imaging (MRI) protocols for several cancers. The real additive role of DWI lies in the "functional" information obtained by probing the free diffusivity of water molecules into intra and inter-cellular spaces that in tumors mainly depend on cellularity. Although DWI has not gained much space in some oncologic scenarios, this non-invasive tool is routinely used in clinical practice and still remains a hot research topic: it has been tested in almost all cancers to differentiate malignant from benign lesions, to distinguish different malignant histotypes or tumor grades, to predict and/or assess treatment responses, and to identify residual or recurrent tumors in follow-up examinations. In this review, we provide an up-to-date overview on the application of DWI in oncology
Non-parametric morphologies of mergers in the Illustris simulation
No full textWe study non-parametric morphologies of mergers events in a cosmological context, using the Illustris project. We produce mock g-band images comparable to observational surveys from the publicly available Illustris simulation idealized mock images at z = 0. We then measure non-parametric indicators: asymmetry, Gini, M20, clumpiness, and concentration for a set of galaxies with M* > 1010 M⊙. We correlate these automatic statistics with the recent merger history of galaxies and with the presence of close companions. Our main contribution is to assess in a cosmological framework, the empirically derived non-parametric demarcation line and average time-scales used to determine the merger rate observationally. We found that 98 per cent of galaxies above the demarcation line have a close companion or have experienced a recent merger event. On average, merger signatures obtained from the G-M20 criterion anti-correlate clearly with the elapsing time to the last merger event.We also find that the asymmetry correlates with galaxy pair separation and relative velocity, exhibiting the larger enhancements for those systems with pair separations d < 50 h-1 kpc and relative velocities V < 350 km s-1. We find that the G-M20 is most sensitive to recent mergers (~0.14 Gyr) and to ongoing mergers with stellar mass ratios greater than 0.1. For this indicator, we compute a merger average observability time-scale of ~0.2 Gyr, in agreement with previous results and demonstrate that the morphologically derived merger rate recovers the intrinsic total merger rate of the simulation and the merger rate as a function of stellar mass.Fil: Bignone, Lucas Axel. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Tissera, Patricia Beatriz. Universidad Andrés Bello; Chile. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Sillero Ros, Guillermo Emanuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Pedrosa, Susana Elizabeth. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Pellizza González, Leonardo Javier. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Argentino de Radioastronomía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Argentino de Radioastronomía; ArgentinaFil: Garcia Lambas, Diego Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin
Appliquée et collaborative ? : essais sur l'évolution de la recherche scientifique d'entreprise
No full textLa science d'entreprise, largement entendue comme la recherche scientifique menée par des entreprises commerciales, constitue une contribution clé à l'innovation. Certaines preuves récentes ont documenté son déclin quantitatif depuis son apogée à la fin des années 1960 / début des années 1970, principalement en raison de la réduction de la taille ou de la fermeture de grands laboratoires d'entreprise (Arora et al., 2018 ; Tijssen, 2004). Malgré ces éléments de preuve, il existe encore de nombreuses zones d'ombre concernant l'étendue et les caractéristiques de ce déclin, car il n'est pas clair si les entreprises se désengagent simplement de la recherche scientifique ou si elles en modifient simplement l'organisation, en passant d'activités de R&D intégrées verticalement à un système plus dynamique de recherche interne appliquée et de collaborations avec les universités.À partir d'un jeu de données original, j'examine ces évolutions et d'autres caractéristiques qualitatives de la science d'entreprise aux États-Unis des années 1980 jusqu'en 2014. Le jeu de données provient de trois sources différentes. Premièrement, toutes les publications scientifiques provenant de Web of Science (WoS), deuxièmement, des données d'entreprise et des brevets provenant de l'édition américaine d'Orbis, et enfin, des citations de littérature non brevetée (NPL) dans la base de données “reliance on science” de Marx & Fuegi (2020).J'aborde trois questions connexes. La première concerne l'augmentation éventuelle du nombre de publications collaboratives entre universités et entreprises, ainsi que les facteurs qui les motivent. Je montre que l'augmentation des collaborations s'accompagne d'une diminution de l'implication directe des entreprises dans la recherche scientifique, mais que cette corrélation est influencée par des facteurs liés à la nature de la science, plutôt que par des considérations commerciales des entreprises. Plus précisément, la probabilité de collaboration entre les entreprises et les universités augmente dans les domaines à évolution rapide, et leur relation dépend de la taille de l'entreprise.La deuxième question s’intéresse au fait de savoir si la science d'entreprise est devenue plus appliquée et moins fondamentale. Je constate que la science d'entreprise est progressivement devenue plus appliquée et moins fondamentale que la science académique, après avoir contrôlé par les domaines et les revues, indépendamment de l'âge et de la taille des entreprises.La troisième question concerne la possibilité que le déclin de la science d'entreprise soit dû, au moins en partie, au court-termisme induit par la pression des actionnaires. À cette fin, j'étudie l'impact des introductions en bourse (IPO) sur les activités de recherche des entreprises. Pour ce faire, j'utilise des données sur la population des entreprises déposant une IPO entre 1996 et 2010 avec au moins une publication ou un brevet. Je trouve un effet positif des IPO tant sur les publications d'entreprise que sur les publications collaboratives. Je ne constate aucun effet sur les citations ultérieures des publications, le caractère fondamental ou appliqué. J'explique ce résultat par un accès accru des entreprises au capital et l'arrivée de nouveaux scientifiques.En conclusion, l'analyse réalisée dans cette thèse éclaire l'évolution de la science d'entreprise de 1980 à 2014, contribuant ainsi à la littérature récente sur le déclin de la science d'entreprise. Le déclin des publications d'entreprise s'accompagne d'une augmentation notable des collaborations entre universités et entreprises. De plus, les entreprises se sont tournées vers une science plus appliquée et moins fondamentale, ce qui soutient l'hypothèse d'un court-termisme accru. Cependant, les preuves de la pression des actionnaires sont moins prononcées, car les entreprises qui se rendent publiques intensifient leurs efforts de recherche au lieu de les restreindre.Corporate science, broadly intended as scientific research conducted by business companies, is a key input to innovation worldwide. Some recent evidence has documented its quantitative decline since its heyday in the late 1960s / early 1970s, as measured by the shrinking share of scientific publications by business-affiliated authors, mostly due to the downsizing or closure of large corporate laboratories (Arora, Belenzon, and Patacconi 2018; Tijssen 2004). Despite this evidence, there are still many shadow zones on both the extent and features of this decline, as it is not clear whether firms are simply disengaging from scientific research or whether they are just changing their organisation by moving from vertically integrated R&D activities towards a more dynamic system of applied in-house research and collaborations with universities.Based on an original dataset, I examine this and other qualitative features of the evolution of corporate science in the United States from the 1980s until recent years. The dataset results from three different data sources. First, all scientific publications from Web of Science (WoS) with at least a US-based author from 1980 to 2014. Second company data and patents from the US edition of Orbis, a large business information database by Bureau van Dijk. Last, non-patent literature (NPL) citations from worldwide patents to scientific publications, as collected in the “reliance on science” database by Marx & Fuegi (2020).I tackle three related questions. The first question addresses the increase in university-industry collaborative publications and the factors driving this trend. I show that the increase in collaborations is accompanied by a decrease in direct corporate involvement in scientific research, but this correlation is influenced by factors related to the nature of science, such as the increasing division of scientific labour and the “burden of knowledge”, rather than commercial considerations of the companies. Specifically, the probability of firms collaborating with universities increases in fast-moving fields, and their relationship depends on firm size.The second question concerns whether corporate science has become more applied, as suggested by the literature, and whether this has come at the expense of its ambition and scope, that is, whether it has also become less basic. I find that corporate science has progressively become more applied and less basic than academic science, after controlling for fields and journals and regardless of the firms’ age and size.The third question concerns whether corporate science's decline may be due, at least in part, to short-termism induced by shareholders' pressure. To this end, I investigate the impact of initial public offerings (IPOs) on firms' research activities. To do so, I use data on the population of firms filing for an IPO from 1996 to 2010 with at least one publication or patent. The results show a positive effect of IPOs on both corporate and collaborative publications. I find no effect on publications' forward citations, basicness or appliedness. I explain this result with firms' increased access to capital and the inflow of new scientists.In conclusion, the analysis carried out in this thesis sheds light on the evolution of corporate science from 1980 to 2014, contributing to the recent literature on the decline of corporate science. The decline in corporate publications is accompanied by a notable increase in university-industry collaborations, signalling a change in companies' approach towards scientific research. Furthermore, companies have moved towards more applied and less basic science, supporting the hypothesis of increased short-termism. However, the evidence for shareholder pressure is less pronounced as companies that go public intensify their research efforts instead of constraining them
