Thermodynamically self-consistent non-stochastic micromagnetic model for the ferromagnetic state

In this work, a self-consistent thermodynamic approach to micromagnetism is presented. The magnetic degrees of freedom are modeled using the Landau-Lifshitz-Baryakhtar theory, that separates the different contributions to the magnetic damping, and thereby allows them to be coupled to the electron and phonon systems in a self-consistent way. We show that this model can quantitatively reproduce ultrafast magnetization dynamics in Nickel.Comment: 5 pages, 3 figure

Phenomenological description of the nonlocal magnetization relaxation in magnonics, spintronics, and domain-wall dynamics

A phenomenological equation called Landau-Lifshitz-Baryakhtar (LLBar) equation, which could be viewed as the combination of Landau-Lifshitz (LL) equation and an extra "exchange damping" term, was derived by Baryakhtar using Onsager's relations. We interpret the origin of this "exchange damping" as nonlocal damping by linking it to the spin current pumping. The LLBar equation is investigated numerically and analytically for the spin wave decay and domain wall motion. Our results show that the lifetime and propagation length of short-wavelength magnons in the presence of nonlocal damping could be much smaller than those given by LL equation. Furthermore, we find that both the domain wall mobility and the Walker breakdown field are strongly influenced by the nonlocal damping.Comment: 10 pages, 6 figure

Experimentos computacionales en la resolución del problema de códigos de identificación

El Problema de Códigos de Identificación (PCI) es un problema NP-difícil relativamente nuevo que, además de contar con aplicaciones concretas (véase el trabajo de Karpovsky, Chakrabarty y Levitin, On a new class of codes for identifying vertices in graphs. IEEE Trans. Inf. Theory 44, 599–611), es desafiante tanto desde el punto de vista teórico como computacional. En particular, se han propuesto algoritmos polinomiales para resolver el PCI sobre clases particulares de grafos y, más recientemente, se ha estudiado el poliedro asociado a su formulación natural donde, en algunos casos, se ha dado la descripción completa para algunas familias de grafos (véase el trabajo de Argiroffo, Bianchi y Wagler, Study of Identifying Code Polyhedra for Some Families of Split Graphs, LNCS 8596, 13–25). En esta comunicación reportamos algunos experimentos computacionales respecto a la performance de un modelo de programación entera para el PCI.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Experimentos computacionales en la resolución del problema de códigos de identificación

El Problema de Códigos de Identificación (PCI) es un problema NP-difícil relativamente nuevo que, además de contar con aplicaciones concretas (véase el trabajo de Karpovsky, Chakrabarty y Levitin, On a new class of codes for identifying vertices in graphs. IEEE Trans. Inf. Theory 44, 599–611), es desafiante tanto desde el punto de vista teórico como computacional. En particular, se han propuesto algoritmos polinomiales para resolver el PCI sobre clases particulares de grafos y, más recientemente, se ha estudiado el poliedro asociado a su formulación natural donde, en algunos casos, se ha dado la descripción completa para algunas familias de grafos (véase el trabajo de Argiroffo, Bianchi y Wagler, Study of Identifying Code Polyhedra for Some Families of Split Graphs, LNCS 8596, 13–25). En esta comunicación reportamos algunos experimentos computacionales respecto a la performance de un modelo de programación entera para el PCI.Sociedad Argentina de Informática e Investigación Operativa (SADIO

Magnetic Vortex Core Reversal by Excitation of Spin Waves

Micron-sized magnetic platelets in the flux closed vortex state are characterized by an in-plane curling magnetization and a nanometer-sized perpendicularly magnetized vortex core. Having the simplest non-trivial configuration, these objects are of general interest to micromagnetics and may offer new routes for spintronics applications. Essential progress in the understanding of nonlinear vortex dynamics was achieved when low-field core toggling by excitation of the gyrotropic eigenmode at sub-GHz frequencies was established. At frequencies more than an order of magnitude higher vortex state structures possess spin wave eigenmodes arising from the magneto-static interaction. Here we demonstrate experimentally that the unidirectional vortex core reversal process also occurs when such azimuthal modes are excited. These results are confirmed by micromagnetic simulations which clearly show the selection rules for this novel reversal mechanism. Our analysis reveals that for spin wave excitation the concept of a critical velocity as the switching condition has to be modified.Comment: Minor corrections and polishing of previous versio

The importance of the weak: Interaction modifiers in artificial spin ices

The modification of geometry and interactions in two-dimensional magnetic nanosystems has enabled a range of studies addressing the magnetic order, collective low-energy dynamics, and emergent magnetic properties, in e.g. artificial spin ice structures. The common denominator of all these investigations is the use of Ising-like mesospins as building blocks, in the form of elongated magnetic islands. Here we introduce a new approach: single interaction modifiers, using slave-mesospins in the form of discs, within which the mesospin is free to rotate in the disc plane. We show that by placing these on the vertices of square artificial spin ice arrays and varying their diameter, it is possible to tailor the strength and the ratio of the interaction energies. We demonstrate the existence of degenerate ice-rule obeying states in square artificial spin ice structures, enabling the exploration of thermal dynamics in a spin liquid manifold. Furthermore, we even observe the emergence of flux lattices on larger length-scales, when the energy landscape of the vertices is reversed. The work highlights the potential of a design strategy for two-dimensional magnetic nano-architectures, through which mixed dimensionality of mesospins can be used to promote thermally emergent mesoscale magnetic states.Comment: 17 pages, including methods, 4 figures. Supplementary information contains 16 pages and 15 figure

ANtiangiogenic Second-line Lung cancer Meta-Analysis on individual patient data in non-small cell lung cancer:ANSELMA

BACKGROUND: Now that immunotherapy plus chemotherapy (CT) is one standard option in first-line treatment of advanced non-small cell lung cancer (NSCLC), there exists a medical need to assess the efficacy of second-line treatments (2LT) with antiangiogenics (AA). We performed an individual patient data meta-analysis to validate the efficacy of these combinations as 2LT. METHODS: Randomised trials of AA plus standard 2LT compared to 2LT alone that ended accrual before 2015 were eligible. Fixed-effect models were used to compute pooled hazard ratios (HRs) for overall survival (OS, main end-point), progression-free survival (PFS) and subgroup analyses. RESULTS: Sixteen trials were available (8,629 patients, 64% adenocarcinoma). AA significantly prolonged OS (HR = 0.93 [95% confidence interval {CI}: 0.89; 0.98], p = 0.005) and PFS (0.80 [0.77; 0.84], p < 0.0001) compared with 2LT alone. Absolute 1-year OS and PFS benefit for AA were +1.8% [-0.4; +4.0] and +3.5% [+1.9; +5.1], respectively. The OS benefit of AA was higher in younger patients (HR = 0.87 [95% CI: 0.76; 1.00], 0.89 [0.81; 0.97], 0.94 [0.87; 1.02] and 1,04 [0.93; 1.17] for patients <50, 50-59, 60-69 and ≥ 70 years old, respectively; trend test: p = 0.02) and in patients who started AA within 9 months after starting the first-line therapy (0.88 [0.82; 0.99]) than in patients who started AA later (0.99 [0.91; 1.08]) (interaction: p = 0.03). Results were similar for PFS. AA increased the risk of hypertension (p < 0.0001), but not the risk of pulmonary thromboembolic events (p = 0.21). CONCLUSIONS: In the 2LT of advanced NSCLC, adding AA significantly prolongs OS and PFS, but the benefit is clinically limited, mainly observed in younger patients and after shorter time since the start of first-line therapy

X-ray imaging of the dynamic magnetic vortex core deformation

Magnetic platelets with a vortex configuration are attracting considerable attention. The discovery that excitation with small in-plane magnetic fields or spin polarised currents can switch the polarisation of the vortex core did not only open the possibility of using such systems in magnetic memories, but also initiated the fundamental investigation of the core switching mechanism itself. Micromagnetic models predict that the switching is mediated by a vortex-antivortex pair, nucleated in a dynamically induced vortex core deformation. In the same theoretical framework, a critical core velocity is predicted, above which switching occurs. Although these models are extensively studied and generally accepted, experimental support has been lacking until now. In this work, we have used high-resolution time-resolved X-ray microscopy to study the detailed dynamics in vortex structures. We could reveal the dynamic vortex core deformation preceding the core switching. Also, the threshold velocity could be measured, giving quantitative comparison with micromagnetic models

Results of screening in early and advanced thoracic malignancies in the EORTC pan-European SPECTAlung platform.

Access to a comprehensive molecular alteration screening is patchy in Europe and quality of the molecular analysis varies. SPECTAlung was created in 2015 as a pan-European screening platform for patients with thoracic malignancies. Here we report the results of almost 4 years of prospective molecular screening of patients with thoracic malignancies, in terms of quality of the program and molecular alterations identified. Patients with thoracic malignancies at any stage of disease were recruited in SPECTAlung, from June 2015 to May 2019, in 7 different countries. Molecular tumour boards were organised monthly to discuss patients' molecular and clinical profile and possible biomarker-driven treatments, including clinical trial options. FFPE material was collected and analysed for 576 patients with diagnosis of pleural, lung, or thymic malignancies. Ultimately, 539 patients were eligible (93.6%) and 528 patients were assessable (91.7%). The turn-around time for report generation and molecular tumour board was 214 days (median). Targetable molecular alterations were observed in almost 20% of cases, but treatment adaptation was low (3% of patients). SPECTAlung showed the feasibility of a pan-European screening platform. One fifth of the patients had a targetable molecular alteration. Some operational issues were discovered and adapted to improve efficiency