Analytical solution of the equation of motion for a rigid domain wall in a magnetic material with perpendicular anisotropy

This paper reports the solution of the equation of motion for a domain wall in a magnetic material which exhibits high magneto-crystalline anisotropy. Starting from the Landau-Lifschitz-Gilbert equation for field-induced motion, we solve the equation to give an analytical expression, which specifies the domain wall position as a function of time. Taking parameters from a Co/Pt multilayer system, we find good quantitative agreement between calculated and experimentally determined wall velocities, and show that high field uniform wall motion occurs when wall rigidity is assumed.Comment: 4 pages, 4 figure

Simultaneous Embeddings with Few Bends and Crossings

A simultaneous embedding with fixed edges (SEFE) of two planar graphs $R$ and $B$ is a pair of plane drawings of $R$ and $B$ that coincide when restricted to the common vertices and edges of $R$ and $B$. We show that whenever $R$ and $B$ admit a SEFE, they also admit a SEFE in which every edge is a polygonal curve with few bends and every pair of edges has few crossings. Specifically: (1) if $R$ and $B$ are trees then one bend per edge and four crossings per edge pair suffice (and one bend per edge is sometimes necessary), (2) if $R$ is a planar graph and $B$ is a tree then six bends per edge and eight crossings per edge pair suffice, and (3) if $R$ and $B$ are planar graphs then six bends per edge and sixteen crossings per edge pair suffice. Our results improve on a paper by Grilli et al. (GD'14), which proves that nine bends per edge suffice, and on a paper by Chan et al. (GD'14), which proves that twenty-four crossings per edge pair suffice.Comment: Full version of the paper "Simultaneous Embeddings with Few Bends and Crossings" accepted at GD '1

Commentary on Raphael's The Transfiguration

Historical sources about Raphael’s death provide different hypotheses about its cause. Continuous fever is the only symptom described. Raphael’s lucidity in managing his last affairs exclude syphilis, made widespread by the French army. The same applies to malaria, which was endemic in Rome. Not even the reference to bloodletting helps us,1 as it was a longstanding therapy to reduce fever. The most prudent hypothesis is an infectious diseas

Aortic regurgitation in athletes. Pieces of the puzzle we have so far omitted

The prevalence of valvular heart disease (VHD) rises with age, reaching 11.7% in individuals older than 75 years.1 In young individuals, VHD is usually related to the presence of a congenital valve abnormality, as bicuspid aortic valve (BAV) or mitral valve prolapse. This is also the case for athletes, where in the presence of these abnormalities few restrictions exist in eligibility for competitive sports participation, even if a strict follow-up would be desirable. BAV is the most common congenital valve abnormality (1%) found in the general population and in athletes. BAV is more prevalent in males and it can lead to aortic regurgitation (AR), aortic stenosis and/or aortic root dilation. At present, no definitive studies have proved that intensive sports participation could worsen the progression of BAV and limited data are available on athletes

On a Tree and a Path with no Geometric Simultaneous Embedding

Two graphs $G_1=(V,E_1)$ and $G_2=(V,E_2)$ admit a geometric simultaneous embedding if there exists a set of points P and a bijection M: P -> V that induce planar straight-line embeddings both for $G_1$ and for $G_2$. While it is known that two caterpillars always admit a geometric simultaneous embedding and that two trees not always admit one, the question about a tree and a path is still open and is often regarded as the most prominent open problem in this area. We answer this question in the negative by providing a counterexample. Additionally, since the counterexample uses disjoint edge sets for the two graphs, we also negatively answer another open question, that is, whether it is possible to simultaneously embed two edge-disjoint trees. As a final result, we study the same problem when some constraints on the tree are imposed. Namely, we show that a tree of depth 2 and a path always admit a geometric simultaneous embedding. In fact, such a strong constraint is not so far from closing the gap with the instances not admitting any solution, as the tree used in our counterexample has depth 4.Comment: 42 pages, 33 figure

Lumbar spinal angiolipomas: report of two cases and review of the literature

n/

Aspirin-dependent effects on purinergic P2Y1 receptor express

Chronic treatment with aspirin in healthy volunteers (HVs) is associated with recovery of adenosine diphosphate (ADP)-induced platelet activation. The purinergic P2Y1 receptor exerts its effects via a Gq-protein, which is the same biochemical pathway activated by thromboxane-A2 receptor. We hypothesized that recovery of ADP-induced platelet activation could be attributed to increased P2Y1 expression induced by chronic aspirin exposure. We performed a multi-phase investigation which embraced both in vitro and in vivo experiments conducted in (1) human megakaryoblastic DAMI cells, (2) human megakaryocytic progenitor cell cultures, (3) platelets obtained from HVs treated with aspirin and (4) platelets obtained from aspirin-treated patients. DAMI cells treated with aspirin or WY14643 (PPARα agonist) had a significant up-regulation of P2Y1 mRNA, which was shown to be a PPARα-dependent process. In human megakaryocytic progenitors, in the presence of aspirin or WY14643, P2Y1 mRNA expression was higher than in mock culture. P2Y1 expression increased in platelets obtained from HVs treated with aspirin for 8 weeks. Platelets obtained from patients who were on aspirin for more than 2 months had increased P2Y1 expression and ADP-induced aggregation compared with patients on aspirin treatment for less than a month. Overall, our results suggest that aspirin induces genomic changes in megakaryocytes leading to P2Y1 up-regulation and that PPARα is the nuclear receptor involved in this regulation. Since P2Y1 is coupled to the same Gq-protein of thromboxane-A2 receptor, platelet adaptation in response to pharmacological inhibition seems not to be receptor specific, but may involve other receptors with the same biochemical pathway

Below-ground arthropod diversity in conventional and organic vineyards: A review

Viticulture is one of the most important agricultural sectors in the Mediterranean area but also one with substantial impact on the soil ecosystem. Some of the most common practices in viticulture, such as tillage, inter-row management, fertilization and use of pesticides, can have important effects on soil communities. The latter significantly contribute to several fundamental soil processes such as decomposition, nutrient and carbon cycling, and microbiota regulation. In perspective, it is therefore necessary to assess the effects of agronomical practices on soil biological communities. The increasing shift towards organic viticulture is seen as a promising management model to maintain soil functionality and preserve soil biodiversity. Below, we present an appraisal of the main practices in conventional and organic viticulture and their possible effects on soil mesofauna. Understanding the extent to which organic practices contribute to maintaining/altering soil functionality and biodiversity is a fundamental step towards the development of an environmentally sustainable viticulture