Exploring jet-launching conditions for supergiant fast X-ray transients

Context. In the magneto-centrifugal mechanism for jet formation, accreting neutron stars are assumed to produce relativistic jets only if their surface magnetic field is weak enough (B ∼ 108 G). However, the most common manifestation of neutron stars are pulsars, whose magnetic field distribution peaks at B ∼ 1012 G. If the neutron star magnetic field has at least this strength at birth, it must decay considerably before jets can be launched in binary systems. Aims. We study the magnetic field evolution of a neutron star that accretes matter from the wind of a high-mass stellar companion so that we can constrain the accretion rate and the impurities in the crust, which are necessary conditions for jet formation. Methods. We solved the induction equation for the diffusion and convection of the neutron star magnetic field confined to the crust, assuming spherical accretion in a simpliflied one-dimensional treatment. We incorporated state-of-the-art microphysics, including consistent thermal evolution profiles, and assumed two different neutron star cooling scenarios based on the superfluidity conditions at the core. Results. We find that in this scenario, magnetic field decay at long timescales is governed mainly by the accretion rate, while the impurity content and thermal evolution of the neutron star play a secondary role. For accretion rates Ṁ ≥ 10-10 M⊙ yr-1, surface magnetic fields can decay up to four orders of magnitude in ∼107 yr, which is the timescale imposed by the evolution of the high-mass stellar companion in these systems. Based on these results, we discuss the possibility of transient jet-launching in strong wind-accreting high-mass binary systems like supergiant fast X-ray transients.Facultad de Ciencias Astronómicas y GeofísicasInstituto Argentino de Radioastronomí

Conditions for jet formation in accreting neutron stars: the magnetic field decay

Accreting neutron stars can produce jets only if they are weakly magnetized (B~10^8 G). On the other hand, neutron stars are compact objects born with strong surface magnetic fields (B~10^12 G). In this work we study the conditions for jet formation in a binary system formed by a neutron star and a massive donor star once the magnetic field has decayed due to accretion. We solve the induction equation for the magnetic field diffusion in a realistic neutron star crust and discuss the possibility of jet launching in systems like the recently detected Supergiant Fast X-ray Transients.Fil: García, Federico. 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: Aguilera, Deborah N.. Ohio University; Estados UnidosFil: Romero, Gustavo Esteban. 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; ArgentinaInternational Astronomical Union SymposiumReino UnidoInternational Astronomical Unio

Neural networks for estimating Macro Asset Pricing model in football clubs

The recent crisis caused by COVID-19 directly affected consumption habits and thestability sof financial markets. In particular, the football industry has been hit hard bythis pandemic and therefore has more volatile stock prices. Given this new scenario,further research is needed to accurately estimate the value of the shares of footballclubs. In this paper, we estimate an asset pricing model in football clubs with differentcompositions of risk nature using non-linear techniques of artificial neural networks.Usually, asset pricing models have been estimated with linear methods such as ordi-nary least squares (...

Soil attributes and root growth of sugar cane with different row spacings and controlled traffic

Orientador: Zigomar Menezes de SouzaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia AgrícolaResumo: O sistema de produção mecanizado da cana-de-açúcar, com ênfase na colheita de cana crua, promove o tráfego intenso sobre o solo, resultando na sua compactação e consequente alteração nos atributos físicos, com reflexos no desenvolvimento radicular e na produtividade da cultura. Com a necessidade de minimizar os efeitos gerados pela compactação, surge o sistema de manejo com controle de tráfego agrícola assistido com piloto automático, onde as cargas dos pneus das máquinas são confinadas em linhas de tráfego permanentes a favor de evitar tráfego na maior parte do campo. O objetivo deste trabalho foi avaliar alterações dos atributos físico-mecânicos do solo e seus efeitos no desenvolvimento do sistema radicular e na produtividade da cana-de-açúcar, com diferentes espaçamentos de plantio e em sistema de manejo com controle de tráfego agrícola, após terceira e quarta colheita mecanizada. A pesquisa foi realizada na Usina Santa Fé, no Município de Nova Europa-SP, num Latossolo Vermelho. O delineamento experimental foi de blocos casualizados, com quatro repetições e três tratamentos: T1 = cana-de-açúcar plantada com espaçamento simples (1,5 m) e manejo sem controle de tráfego; T2 = cana-de-açúcar plantada com espaçamento simples (1,5 m) e manejo com controle de tráfego; T3 = cana-de-açúcar plantada com espaçamento duplo combinado (1,50 x 0,90 m) e manejo com controle de tráfego. As amostragens de solo foram realizadas na linha de plantio, no canteiro e na linha do rodado, nas camadas de 0,00-0,10; 0,10-0,20; 0,20-0,30; 0,30-0,40; 0,40-0,50; 0,50-0,70; e 0,70-1,00 m. Os atributos físicos: densidade do solo, resistência do solo à penetração, porosidade, estabilidade e resistência tênsil de agregados, assim como a produtividade da cultura, foram avaliados nos dois anos de estudo. A retenção de água no solo, o carbono orgânico total, a capacidade de suporte de carga e o sistema radicular foram avaliados somente após a terceira colheita. A capacidade de suporte de carga do solo foi avaliada na linha do rodado e no canteiro, na camada superficial de 0,00-0,10 m e na camada de máxima resistência do solo à penetração, identificada na camada de 0,20-0,30 m. Os sistemas de manejo com controle de tráfego preservaram a qualidade física do solo na região do canteiro e da linha de plantio (menor densidade do solo e maior macroporosidade), e proporcionaram maior compactação na linha do rodado. A pressão de preconsolidação nos manejos T2 e T3 foi maior na linha do rodado, enquanto no manejo T1, foi maior no canteiro. O uso do controle de tráfego promoveu maior desenvolvimento do sistema radicular, com incremento da biomassa seca de 17,9% no T2 e de 18,5% no T3 em relação ao manejo sem controle de tráfego. Os manejos com controle de tráfego apresentaram ganhos na produtividade de 9 e 12% no T2 e, de 21 e 18% no T3 na terceira e quarta colheita, respectivamente, em relação ao manejo sem controle de tráfegoAbstract: Mechanized sugar cane production system, especially green cane harvesting, generates intense traffic over the soil, leads to soil compaction and consequent alteration of its physical attributes, reflecting on the root growth and crop productivity. With the need to minimize compaction effects, a management system with controlled traffic assisted with automatic steering emerges, in which machine wheel loads are confined into permanent traffic lines in order to avoid traffic at most part of the field. This study aimed to evaluate changes in the soil physical and mechanical attributes, and their effects on root system growth and sugar cane productivity, planted with different row spacings and controlled traffic management systems, after the third and fourth mechanical harvest. The research was carried out on an Oxisol at the Santa Fé Sugar Mill [Usina Santa Fé], in the city of Nova Europa, state of São Paulo. The experiment was implemented with a randomized block design, with four replications and three treatments: T1 - sugar cane planted with single row spacing (1.5 m) and harvested without controlled traffic; T2 - sugar cane planted with single row spacing (1.5 m) and harvested with controlled traffic; and T3 - sugar cane planted with double combined row spacing (1.50 x 0.90 m) and harvested with controlled traffic. Soil samples were collected at the plant row, seedbed and inter-row center, at the layers 0.00-0.10, 0.10-0.20, 0.20-0.30, 0.30-0.40, 0.40-0.50, 0.50-0.70 and 0.70-1.00 m. The physical attributes of bulk density, soil penetration resistance, soil porosity, aggregate stability and tensile strength of aggregates, as well as the crop yield, were evaluated in the two years of the study. Soil water retention, total organic carbon, load-bearing capacity and root system were evaluated only after the third harvest. The load-bearing capacity was assessed at the inter-row center and seedbed, at the superficial layer of 0.00-0.10 m and at the maximum penetration resistance layer of 0.20-0.30 m. The management systems with controlled traffic preserved the soil physical quality at the seedbed and plant row (lower bulk density and higher macroporosity), and increased soil compaction at the inter-row center. Preconsolidation pressure in the T2 and T3 conditions was higher at the inter-row center, while in T1, it was higher at the seedbed. Controlled traffic promoted higher root system growth, with 17.9% increase of dry matter in T2 and 18.5% in T3 in relation to the management system without controlled traffic. The adoption of controlled traffic resulted in crop yield increases of 9 and 12% in T2, and 21 and 18% in T3 at the third and fourth harvest, respectively, in relation to management without controlled trafficMestradoAgua e SoloMestre em Engenharia Agrícola2016/14751-6FAPES

Forecasting model with machine learning in higher education ICFES exams

In this paper, we proposed to make different forecasting models in the University education through the algorithms K-means, K-closest neighbor, neural network, and naïve Bayes, which apply to specific exams of engineering, licensed and scientific mathematical thinking in Saber Pro of Colombia. ICFES Saber Pro is an exam required for the degree of all students who carry out undergraduate programs in higher education. The Colombian government regulated this exam in 2009 in the decree 3963 intending to verify the development of competencies, knowledge level, and quality of the programs and institutions. The objective is to use data to convert into information, search patterns, and select the best variables and harness the potential of data (average 650.000 data per semester). The study has found that the combination of features was: women have greater participation (68%) in Mathematics, Engineering, and Teaching careers, the urban area continues to be the preferred place to apply for higher studies (94%), Internet use increased by 50% in the last year, the support of the family nucleus is still relevant for the support in the formation of the children

Microbiological Characterization of Cutibacterium acnes Strains Isolated from Prosthetic Joint Infections

Aims: This study aimed to characterize 79 Cutibacterium acnes strains isolated from prosthetic joint infections (PJIs) originated from eight European hospitals. Methods: Isolates were phylotyped according to the single-locus sequence typing (SLST) scheme. We evaluated the ability of the biofilm formation of C. acnes strains isolated from PJIs and 84 isolates recovered from healthy skin. Antibiotic susceptibility testing of planktonic and biofilm cells of PJI isolates and skin isolates was performed. Results: Most of the isolates from PJIs belonged to the SLST class H/phylotype IB (34.2%), followed by class D/phylotype IA1 (21.5%), class A/phylotype IA1 (18.9%), and class K/phylotype II (13.9%). All tested isolates were biofilm producers; no difference in biofilm formation was observed between the healthy skin group and the PJI group of strains. Planktonic and sessile cells of C. acnes remained highly susceptible to a broad spectrum of antibiotics, including beta-lactams, clindamycin, fluoroquinolones, linezolid, rifampin, and vancomycin. The minimal inhibitory concentrations (MICs) for planktonic and biofilm states coincided in most cases. However, the minimal biofilm eradication concentration (MBEC) was high for all antimicrobial drugs tested (>32 mg/L), except for rifampin (2 mg/L). Conclusions: C. acnes strains isolated from healthy skin were able to produce biofilm to the same extent as isolates recovered from PJIs. All C. acnes strains in planktonic and sessile states were susceptible to most antibiotics commonly used for PJI treatment, although rifampin was the only antimicrobial agent able to eradicate C. acnes embedded in biofilm. Keywords: Cutibacteriumacnes; antimicrobial susceptibility; biofilm; phylotyping; prosthetic joint infection

Validation of Portable Mobile Mapping System for inspection tasks in thermal and fluid-mechanical facilities

20 p.The three-dimensional registration of industrial facilities has a great importance for maintenance, inspection, and safety tasks and it is a starting point for new improvements and expansions in the industrial facilities context. In this paper, a comparison between the results obtained using a novel portable mobile mapping system (PMMS) and a static terrestrial laser scanner (TLS), widely used for 3D reconstruction in civil and industrial scenarios, is carried out. This comparison is performed in the context of industrial inspection tasks, specifically in the thermal and fluid-mechanics facilities in a hospital. The comparison addresses the general reconstruction of a machine room, focusing on the quantitative and qualitative analysis of different elements (e.g., valves, regulation systems, burner systems and tanks, etc.). The validation of the PMMS is provided considering the TLS as ground truth and applying a robust statistical analysis. Results come to confirm the suitability of the PMMS to perform inspection tasks in industrial facilities.S

The Royal Shipyard of Barcelona during the Early Modern Era : The Great Galley Factory of the Spanish Monarchy (16th-19th centuries)

Peer reviewe

Análisis de los cambios estratégicos con impacto positivo en los modelos de negocio de grupos corporativos familiares de la ciudad de Cuenca que se realizaron durante la crisis del Coronavirus

Analizar el impacto de la COVID-19 en los modelos de negocio de las empresas de la ciudad de Cuenca permite reflexionar sobre el entendimiento de la vulnerabilidad o resiliencia de sus modelos de gestión. Aplicando una réplica del estudio Analyzing the impact of the coronavirus crisis on business models, de Ritter y Pedersen (2020a), con el enfoque del modelo de alineación de cuadrados en 14 casos de grupos corporativos familiares de la ciudad de Cuenca que participan en el estudio, se logró un análisis de los impactos de la pandemia de la COVID-19 en sus modelos de negocio. Al comparar los resultados con los del estudio en Dinamarca, se concluye con la importancia de reconocer los niveles de vulnerabilidad y resiliencia de los modelos de negocio ante una crisis, con lo que se ofrece una herramienta importante para tomar decisiones estratégicas de gestión para la nueva normalidad.                                                                  Palabras clave: Impacto, estrategia, análisis, resiliencia, empresas, crisis, COVID-19. Abstractnalyzing the impact of the COVID-19 on business models of companies in the city of Cuenca provides reflections on the understanding of the vulnerability or resilience of their management models. Applying, a replica of the study “Analyzing the impact of the coronavirus crisis on business models” (Ritter & Pedersen, 2020a) using the square alignment model approach in 14 cases of family corporate groups in the city of Cuenca that participate in the study, an analysis of the impacts of the COVID-19 pandemic on their business models was achieved and when comparing the results with those of the study in Denmark, it is concluded with noting the importance of recognizing the levels of vulnerability and resilience of the business models in the face or a crisis thereby offering an important tool for making strategic management decisions for the new normal.  Keywords: Impact, strategy, analysis, resilience, enterprise, crisis, COVID-1