Estudio de aceros al manganeso nitrogenados

El presente trabajo se basa en la comparación de características microestructurales y mecánicas de aceros al manganeso (Hadfield) con y sin nitrógeno. Se ha observado que el nitrógeno aumenta la resistencia al impacto y la dureza del acero al manganeso. Al mismo tiempo, disminuye la pérdida de masa en condiciones de trabajo de desgaste.The present work is based on the comparison of microstructural and mechanical characteristics of steels to manganese (Hadfield)with and without nitrogen. It has been observed that nitrogen increases the impact strength and hardness of manganese steel. At the same time, it reduces the loss of mass in wearresistant working conditions

Estudio de aceros al manganeso nitrogenados

El presente trabajo se basa en la comparación de características microestructurales y mecánicas de aceros al manganeso (Hadfield) con y sin nitrógeno. Se ha observado que el nitrógeno aumenta la resistencia al impacto y la dureza del acero al manganeso. Al mismo tiempo, disminuye la pérdida de masa en condiciones de trabajo de desgaste.The present work is based on the comparison of microstructural and mechanical characteristics of steels to manganese (Hadfield)with and without nitrogen. It has been observed that nitrogen increases the impact strength and hardness of manganese steel. At the same time, it reduces the loss of mass in wearresistant working conditions

Visualizing the Feature Importance for Black Box Models

In recent years, a large amount of model-agnostic methods to improve the transparency, trustability and interpretability of machine learning models have been developed. We introduce local feature importance as a local version of a recent model-agnostic global feature importance method. Based on local feature importance, we propose two visual tools: partial importance (PI) and individual conditional importance (ICI) plots which visualize how changes in a feature affect the model performance on average, as well as for individual observations. Our proposed methods are related to partial dependence (PD) and individual conditional expectation (ICE) plots, but visualize the expected (conditional) feature importance instead of the expected (conditional) prediction. Furthermore, we show that averaging ICI curves across observations yields a PI curve, and integrating the PI curve with respect to the distribution of the considered feature results in the global feature importance. Another contribution of our paper is the Shapley feature importance, which fairly distributes the overall performance of a model among the features according to the marginal contributions and which can be used to compare the feature importance across different models.Comment: To Appear in Machine Learning and Knowledge Discovery in Databases: European Conference, ECML PKDD 2018, Dublin, Ireland, September 10 to 14, 2018, Proceedings, Part

Segmentation of sales for a mobile phone service through CART classification tree algorithm

The work consisted of detailing the CRISP-DM method in order to identify optimal groups of customers who are more likely to migrate from a prepaid to postpaid option in order to formulate an improvement plan for in call management by sorting the database. Classification models were applied to analyze the characteristics generated by the purchase of the different services. The CART Classification Tree algorithm. As a result, groups differentiated by probabilities of sales success (migrate from a prepaid to postpaid plan) were found, segments that reflect particular needs and characteristics to design marketing actions focused on the objective of increasing the effectiveness rate, contact information, and sales increase

Microdureza y tipos de esmalte en molares humanos

En cada tipo de esmalte la estructuración de los prismas y cristales responde a la demanda biomecánica. El esmalte radial, presenta mayor resistencia al desgaste. El esmalte con bandas de Hunter Schreger y el irregular evitan la propagación de fracturas. La dureza del esmalte tiene relación directa con la resistencia a la abrasión. El propósito fue identificar tipos de esmalte y establecer su relación con la microdureza. 12 coronas de molares inferiores seccionadas longitudinalmente fueron incluidas, grabadas y observadas al MEB. Las micrografías se registraron en caras libres y cúspides en el tercio externo (A) y en el tercio interno (B) donde también se midió la microdureza Vickers. Las caras libres mostraron esmalte radial en la zona externa y con bandas en la interna. Las bandas ocupaban el mayor espesor del esmalte. En el tercio cervical el único tipo de esmalte era el radial. En la cúspide lingual el esmalte interno era de tipo irregular y se completaba con radial hasta la superficie externa. La microdureza (A) Hv100=380,59Vk; (B) Hv100=316,27 Vk En la vestibular el interno mostraba bandas y el externo era radial. La microdureza en (A) Hv100= 390,8Vk, en (B) Hv100=326,31 Vk. La ubicación externa, mayor dureza del esmalte radial y su combinación con esmalte interno irregular o con bandas constituyen una adaptación biomecánica de las áreas funcionales.In every type of tooth enamel, the structure of prisms and crystals makes it possible to meet the biomechanical demand. The radial enamel type, presents higher abrasion resistance. The enamel with Hunter Schreger bands and the irregular enamel avoid fracture propagation. Enamel hardness it has a direct relationship with abrasion resistance. The purpose was to identify the enamel types and to establish their relationship with microhardness. Twelve inferior molar crowns were longitudinally cut, embedded, grinded (A) Hv100 =380,59Vk; (B) Hv100 =316,27 Vk.ln the vestibular cusp the inner enamel showed bands and the outer enamel was of the radial type. Microhardness was Hv100 = 390,8Vk in (A); Hv100 =326,31 Vk in(B). The outer and harder radial etched and observed under a SEM in free faces and cusps in the outer third (A) and in the inner third (B), where Vickers microhardness was also measured.Radial enamel was identified in the outer zone of the free faces and enamel with bands in the inner.The bands occupied the thickest portion of the enamel. The radial enamel was the only one present in the cervical third. In the lingual cusp the inner enamel was of the irregular type and it was completed with radial as far as the outer surface Microhardness value was enamel type, combined with the inner enamel type, either irregular or with bands, constitute a biomechanical adaptation of the functional.Facultad de Odontologí

Microdureza y tipos de esmalte en molares humanos

En cada tipo de esmalte la estructuración de los prismas y cristales responde a la demanda biomecánica. El esmalte radial, presenta mayor resistencia al desgaste. El esmalte con bandas de Hunter Schreger y el irregular evitan la propagación de fracturas. La dureza del esmalte tiene relación directa con la resistencia a la abrasión. El propósito fue identificar tipos de esmalte y establecer su relación con la microdureza. 12 coronas de molares inferiores seccionadas longitudinalmente fueron incluidas, grabadas y observadas al MEB. Las micrografías se registraron en caras libres y cúspides en el tercio externo (A) y en el tercio interno (B) donde también se midió la microdureza Vickers. Las caras libres mostraron esmalte radial en la zona externa y con bandas en la interna. Las bandas ocupaban el mayor espesor del esmalte. En el tercio cervical el único tipo de esmalte era el radial. En la cúspide lingual el esmalte interno era de tipo irregular y se completaba con radial hasta la superficie externa. La microdureza (A) Hv100=380,59Vk; (B) Hv100=316,27 Vk En la vestibular el interno mostraba bandas y el externo era radial. La microdureza en (A) Hv100= 390,8Vk, en (B) Hv100=326,31 Vk. La ubicación externa, mayor dureza del esmalte radial y su combinación con esmalte interno irregular o con bandas constituyen una adaptación biomecánica de las áreas funcionales.In every type of tooth enamel, the structure of prisms and crystals makes it possible to meet the biomechanical demand. The radial enamel type, presents higher abrasion resistance. The enamel with Hunter Schreger bands and the irregular enamel avoid fracture propagation. Enamel hardness it has a direct relationship with abrasion resistance. The purpose was to identify the enamel types and to establish their relationship with microhardness. Twelve inferior molar crowns were longitudinally cut, embedded, grinded (A) Hv100 =380,59Vk; (B) Hv100 =316,27 Vk.ln the vestibular cusp the inner enamel showed bands and the outer enamel was of the radial type. Microhardness was Hv100 = 390,8Vk in (A); Hv100 =326,31 Vk in(B). The outer and harder radial etched and observed under a SEM in free faces and cusps in the outer third (A) and in the inner third (B), where Vickers microhardness was also measured.Radial enamel was identified in the outer zone of the free faces and enamel with bands in the inner.The bands occupied the thickest portion of the enamel. The radial enamel was the only one present in the cervical third. In the lingual cusp the inner enamel was of the irregular type and it was completed with radial as far as the outer surface Microhardness value was enamel type, combined with the inner enamel type, either irregular or with bands, constitute a biomechanical adaptation of the functional.Facultad de Odontologí

Microdureza y tipos de esmalte en molares humanos

En cada tipo de esmalte la estructuración de los prismas y cristales responde a la demanda biomecánica. El esmalte radial, presenta mayor resistencia al desgaste. El esmalte con bandas de Hunter Schreger y el irregular evitan la propagación de fracturas. La dureza del esmalte tiene relación directa con la resistencia a la abrasión. El propósito fue identificar tipos de esmalte y establecer su relación con la microdureza. 12 coronas de molares inferiores seccionadas longitudinalmente fueron incluidas, grabadas y observadas al MEB. Las micrografías se registraron en caras libres y cúspides en el tercio externo (A) y en el tercio interno (B) donde también se midió la microdureza Vickers. Las caras libres mostraron esmalte radial en la zona externa y con bandas en la interna. Las bandas ocupaban el mayor espesor del esmalte. En el tercio cervical el único tipo de esmalte era el radial. En la cúspide lingual el esmalte interno era de tipo irregular y se completaba con radial hasta la superficie externa. La microdureza (A) Hv100=380,59Vk; (B) Hv100=316,27 Vk En la vestibular el interno mostraba bandas y el externo era radial. La microdureza en (A) Hv100= 390,8Vk, en (B) Hv100=326,31 Vk. La ubicación externa, mayor dureza del esmalte radial y su combinación con esmalte interno irregular o con bandas constituyen una adaptación biomecánica de las áreas funcionales.In every type of tooth enamel, the structure of prisms and crystals makes it possible to meet the biomechanical demand. The radial enamel type, presents higher abrasion resistance. The enamel with Hunter Schreger bands and the irregular enamel avoid fracture propagation. Enamel hardness it has a direct relationship with abrasion resistance. The purpose was to identify the enamel types and to establish their relationship with microhardness. Twelve inferior molar crowns were longitudinally cut, embedded, grinded (A) Hv100 =380,59Vk; (B) Hv100 =316,27 Vk.ln the vestibular cusp the inner enamel showed bands and the outer enamel was of the radial type. Microhardness was Hv100 = 390,8Vk in (A); Hv100 =326,31 Vk in(B). The outer and harder radial etched and observed under a SEM in free faces and cusps in the outer third (A) and in the inner third (B), where Vickers microhardness was also measured.Radial enamel was identified in the outer zone of the free faces and enamel with bands in the inner.The bands occupied the thickest portion of the enamel. The radial enamel was the only one present in the cervical third. In the lingual cusp the inner enamel was of the irregular type and it was completed with radial as far as the outer surface Microhardness value was enamel type, combined with the inner enamel type, either irregular or with bands, constitute a biomechanical adaptation of the functional.Facultad de Odontologí

Survey on retinopathy of prematurity (ROP) in Italy

This study aims to investigate the incidence and the relative risk factors of retinopathy of prematurity (ROP) and posterior-ROP (P-ROP): ROP in Zone I and posterior Zone II, as well as to analyze the occurrence of surgical treatment of ROP and to evaluate the short term outcome of the disease in Italy

Principal variable selection to explain grain yield variation in winter wheat from features extracted from UAV imagery

Background: Automated phenotyping technologies are continually advancing the breeding process. However, collecting various secondary traits throughout the growing season and processing massive amounts of data still take great efforts and time. Selecting a minimum number of secondary traits that have the maximum predictive power has the potential to reduce phenotyping efforts. The objective of this study was to select principal features extracted from UAV imagery and critical growth stages that contributed the most in explaining winter wheat grain yield. Five dates of multispectral images and seven dates of RGB images were collected by a UAV system during the spring growing season in 2018. Two classes of features (variables), totaling to 172 variables, were extracted for each plot from the vegetation index and plant height maps, including pixel statistics and dynamic growth rates. A parametric algorithm, LASSO regression (the least angle and shrinkage selection operator), and a non-parametric algorithm, random forest, were applied for variable selection. The regression coefficients estimated by LASSO and the permutation importance scores provided by random forest were used to determine the ten most important variables influencing grain yield from each algorithm. Results: Both selection algorithms assigned the highest importance score to the variables related with plant height around the grain filling stage. Some vegetation indices related variables were also selected by the algorithms mainly at earlier to mid growth stages and during the senescence. Compared with the yield prediction using all 172 variables derived from measured phenotypes, using the selected variables performed comparable or even better. We also noticed that the prediction accuracy on the adapted NE lines (r = 0.58–0.81) was higher than the other lines (r = 0.21–0.59) included in this study with different genetic backgrounds. Conclusions: With the ultra-high resolution plot imagery obtained by the UAS-based phenotyping we are now able to derive more features, such as the variation of plant height or vegetation indices within a plot other than just an averaged number, that are potentially very useful for the breeding purpose. However, too many features or variables can be derived in this way. The promising results from this study suggests that the selected set from those variables can have comparable prediction accuracies on the grain yield prediction than the full set of them but possibly resulting in a better allocation of efforts and resources on phenotypic data collection and processing

La falsificazione epigrafica. Questioni di metodo e casi di studio

This paper aims to reconsider the manuscript by Jacopo Valvasone (1499-1570), formerly owned by the Earl of Leicester (now British Library, Additional MS 49369), which Theodor Mommsen borrowed and inspected in 1876, just before the publication of the second part of CIL V. In the letter that he wrote to thank the Vicar and Librarian of Halkham Hall, Mommsen declared that Valvasone joined \u201cthe the long list of forgers\u201d. The analysis of forgeries in Valvasone\u2019s manuscript could show whether Mommsen was right in his opinion