Stress Intensity Factors for Embedded, Surface, and Corner Cracks in Finite-Thickness Plates Subjected to Tensile Loading

The aim of this study is to obtain the stress intensity factor (SIF) along the crack front of elliptical cracks located in finite-thickness plates subjected to imposed displacement or applied tensile load, for different crack geometries (relative depths and aspect ratios) and crack configurations (embedded, surface, and corner). The SIF was calculated from the J-integral, obtained by the finite element method. The results show how the SIF grows with the increase in the relative crack depth and with the decrease in the aspect ratio, with the corner crack being the most dangerous configuration and the embedded crack the most favorable configuration. By increasing the plate length, the SIF rises when the plate is under imposed displacement and decreases when the plate is subjected to applied tensile load, both cases tending towards the same SIF curve.

Descriptive Political Representation of Latin Americans in Spanish Local Politics: Demographic Concentration, Political Opportunities, and Parties’ Inclusiveness

Latin Americans represent one of the most sizable migrant communities in Spain. Yet, unlike other minority groups, they count with longer migration tradition, linguistic and cultural similarities with the Spanish population, and easier access to Spanish nationality. Drawing on original data covering a large number of candidates ( N = 5,055), this article examines whether this apparently favorable configuration guarantees the nomination of candidates from this minority group at local elections in municipalities with strong demographic presence of Latin American residents. Our findings indicate that this group is still underrepresented in Spanish politics. Few Latin American candidates are fielded by political parties, and even fewer (<2%) manage to achieve elected office. To interpret these results, we examine the extent to which Spanish parties field minority candidates. We show that while some parties are proactively including these candidates, only few nominate them in secure positions of the electoral lists and that Spanish parties’ inclusiveness does not seem to be aligned with Latin American voters’ partisan preferences.

Ranking and Selection with Covariates for Personalized Decision Making

We consider a problem of ranking and selection via simulation in the context of personalized decision making, in which the best alternative is not universal, but varies as a function of some observable covariates. The goal of ranking and selection with covariates (R&S-C) is to use simulation samples to obtain a selection policy that specifies the best alternative with a certain statistical guarantee for subsequent individuals upon observing their covariates. A linear model is proposed to capture the relationship between the mean performance of an alternative and the covariates. Under the indifference-zone formulation, we develop two-stage procedures for both homoscedastic and heteroscedastic simulation errors, respectively, and prove their statistical validity in terms of average probability of correct selection. We also generalize the well-known slippage configuration and prove that the generalized slippage configuration is the least favorable configuration for our procedures. Extensive numerical experiments are conducted to investigate the performance of the proposed procedures, the experimental design issue, and the robustness to the linearity assumption. Finally, we demonstrate the usefulness of R&S-C via a case study of selecting the best treatment regimen in the prevention of esophageal cancer. We find that by leveraging disease-related personal information, R&S-C can substantially improve patients’ expected quality-adjusted life years by providing a patient-specific treatment regimen.

Use of Space Syntax through the map of segments for diagnostic integration and choice normalized in the City of Campina Grande - Brazil

The article presents the profile of the city of Campina Grande, Brazil, from the perspective of the Space Syntax of the Theory of Social Logic of Space. In the methodology adopted, we used the model that starts from the Road Centre Line (RCL) map elaboration, which served as a basis for obtaining the Angular Segment Analysis, via Depthmapand QGIS software, generating the syntactic measures presented in the results. The objectives proposed in this study were achieved, for the results show that in the city there are spaces with organic and planned characteristics, which reflect socio-cultural aspects of occupation and settlement of the area along its predominantly heterogeneous formation. As for the urban form, there is a configuration composed of an integrating nucleus, located in the urban center; as for the scores presented, there are average values of NAIN (1.007), NACH (0.911) and INCH (12,213) measures, in which 48% with 40%, 54% and 48%, respectively, of the neighborhoods with average scores higher than the index presented by the city's configurational analysis. Most of the territory presents values above the average values for the city and for the Brazilian territory. Thus, it is concluded that the central regions seem to present, according to the data obtained, a more favorable configuration for mobility and accessibility, having in the peripheral neighborhoods segregationist aspects that can explain the restriction of movement of individuals regarding the access of goods and services in the city.

Intercalation of Mn in graphene/Cu(111) interface: insights to the electronic and magnetic properties from theory

The effect of Mn intercalation on the atomic, electronic and magnetic structure of the graphene/Cu(111) interface is studied using state-of-the-art density functional theory calculations. Different structural models of the graphene–Mn–Cu(111) interface are investigated. While a Mn monolayer placed between graphene and Cu(111) (an unfavorable configuration) yields massive rearrangement of the graphene-derived $$\pi $$ π bands in the vicinity of the Fermi level, the possible formation of a $$\hbox {Cu}_2$$ Cu 2 Mn alloy at the interface (a favorable configuration) preserves the linear dispersion for these bands. The deep analysis of the electronic states around the Dirac point for the graphene/$$\hbox {Cu}_2$$ Cu 2 Mn/Cu(111) system allows to discriminate between contributions from three carbon sublattices of a graphene layer in this system and to explain the bands’ as well as spins’ topology of the electronic states around the Fermi level.

Repeating fast radio bursts caused by small bodies orbiting a pulsar or a magnetar

Context. Asteroids orbiting into the highly magnetized and highly relativistic wind of a pulsar offer a favorable configuration for repeating fast radio bursts (FRB). The body in direct contact with the wind develops a trail formed of a stationary Alfvén wave, called an Alfvén wing. When an element of wind crosses the Alfvén wing, it sees a rotation of the ambient magnetic field that can cause radio-wave instabilities. In the observer’s reference frame, the waves are collimated in a very narrow range of directions, and they have an extremely high intensity. A previous work, published in 2014, showed that planets orbiting a pulsar can cause FRBs when they pass in our line of sight. We predicted periodic FRBs. Since then, random FRB repeaters have been discovered. Aims. We present an upgrade of this theory with which repeaters can be explained by the interaction of smaller bodies with a pulsar wind. Methods. Considering the properties of relativistic Alfvén wings attached to a body in the pulsar wind, and taking thermal consideration into account, we conducted a parametric study. Results. We find that FRBs, including the Lorimer burst (30 Jy), can be explained by small-size pulsar companions (1 to 10 km) between 0.03 and 1 AU from a highly magnetized millisecond pulsar. Some parameter sets are also compatible with a magnetar. Our model is compatible with the high rotation measure of FRB 121102. The bunched timing of the FRBs is the consequence of a moderate wind turbulence. An asteroid belt composed of fewer than 200 bodies would suffice for the FRB occurrence rate measured with FRB 121102. Conclusions. After this upgrade, this model is compatible with the properties discovered since its first publication in 2014, when repeating FRBs were still unknown. It is based on standard physics and on common astrophysical objects that can be found in any type of galaxy. It requires 1010 times less power than (common) isotropic-emission FRB models.

Inhibition of Tyrosine-Phosphorylated STAT3 in Human Breast and Lung Cancer Cells by Manuka Honey is Mediated by Selective Antagonism of the IL-6 Receptor

Aberrantly high levels of tyrosine-phosphorylated signal transducer and activator of transcription 3 (p-STAT3) are found constitutively in ~50% of human lung and breast cancers, acting as an oncogenic transcription factor. We previously demonstrated that Manuka honey (MH) inhibits p-STAT3 in breast cancer cells, but the exact mechanism remained unknown. Herein, we show that MH-mediated inhibition of p-STAT3 in breast (MDA-MB-231) and lung (A549) cancer cell lines is accompanied by decreased levels of gp130 and p-JAK2, two upstream components of the IL-6 receptor (IL-6R) signaling pathway. Using an ELISA-based assay, we demonstrate that MH binds directly to IL-6Rα, significantly inhibiting (~60%) its binding to the IL-6 ligand. Importantly, no evidence of MH binding to two other cytokine receptors, IL-11Rα and IL-8R, was found. Moreover, MH did not alter the levels of tyrosine-phosphorylated or total Src family kinases, which are also constitutively activated in cancer cells, suggesting that signaling via other growth factor receptors is unaffected by MH. Binding of five major MH flavonoids (luteolin, quercetin, galangin, pinocembrin, and chrysin) was also tested, and all but pinocembrin could demonstrably bind IL-6Rα, partially (30–35%) blocking IL-6 binding at the highest concentration (50 μM) used. In agreement, each flavonoid inhibited p-STAT3 in a dose-dependent manner, with estimated IC50 values in the 3.5–70 μM range. Finally, docking analysis confirmed the capacity of each flavonoid to bind in an energetically favorable configuration to IL-6Rα at a site predicted to interfere with ligand binding. Taken together, our findings identify IL-6Rα as a direct target of MH and its flavonoids, highlighting IL-6R blockade as a mechanism for the anti-tumor activity of MH, as well as a viable therapeutic target in IL-6-dependent cancers.

Workshop de agricultura digital e monitoramento agrícola por satélite – Uma contribuição da união entre ensino, extensão e pesquisa

Information from remote sensing (SR), in the form of images or maps, and the reports or processes associated with its interpretation, have a high potential to be an axis and motivation for informed debates about the reality of regional agricultural production. This process is bidirectional, because the accurate interpretation of the information recorded by the sensors also depends on a deep knowledge of the process and reality of the field, which is recorded by the producer and his team over the years. In this scenario, the Agricultural Satellite Monitoring Workshop was organized, consisting of a motivational presentation, technical visit and video-reports on the monitoring of commercial crops by SR in the 2017/2018 harvest. The importance of this work lies in the identification of methodologies that will stimulate professionals, academics and the general public to participate in processes of sharingf experiences and creation of knowledge in the interface between university teaching, research and extension. The results indicate that SR monitoring of commercial rice and soybean crops, and the presentation of results in the form of a workshop on the property, is a favorable configuration for extension, research and teaching activities between university and company, and motivating covenants between them.

Nanoscale Lamb wave–driven motors in nonliquid environments

Achieving light-driven motions in nonliquid environments presents formidable challenges, because microsized objects experience strong dry adhesion and intend to be stuck to contact surfaces with great tenacity. Here, in air and vacuum, we show rotary locomotion of a micrometer-sized metal plate with ~30 nm thickness, revolving around a microfiber. This motor is powered by pulsed light guided into the fiber as a coordinated consequence of an optically excited Lamb wave on the plate and favorable configuration of plate-fiber geometry. The motor, actuated by designed light pulses, crawls stepwise with subnanometer locomotion resolution. Furthermore, we can control the rotation velocity and step resolution by varying the repetition rate and pulse power, respectively. A light-actuated micromirror scanning with 0.001° resolution is then demonstrated on the basis of this motor. It offers unprecedented application potential for integrated micro-opto-electromechanical systems, outer-space all-optical precision mechanics and controls, and laser scanning for miniature lidar systems.