Euler integral as a source of chaos in the three–body problem

In this paper we address, from a purely numerical point of view, the question, raised in Pinzari (2019), Pinzari (2020), and partly considered in Pinzari (2020), Di Ruzza et al. (2020), Chen and Pinzari (2021), whether a certain function, referred to as “Euler Integral”, is a quasi-integral along the trajectories of the three-body problem. Differently from our previous investigations, here we focus on the region of the “unperturbed separatrix”, which turns to be complicated by a collision singularity. Concretely, we reduce the Hamiltonian to two degrees of freedom and, after fixing some energy level, we discuss in detail the resulting three-dimensional phase space around an elliptic and an hyperbolic periodic orbit. After measuring the strength of variation of the Euler Integral (which are in fact small), we detect the existence of chaos closely to the unperturbed separatrix. The latter result is obtained through a careful use of the machinery of covering relations, developed in Gierzkiewicz and Zgliczyński (2019), Zgliczynski and Gidea (2004), Wilczak and Zgliczynski (2003)

Improving the ability to write persuasive texts in a boy with autism spectrum disorder: outcomes of an intervention

In this paper, we describe an intervention implemented to assist a 13.2-year-old boy with Autism Spectrum Disorder, G, without intellectual disability, aimed at improving his ability to compose persuasive texts. There was an initial assessment (baseline), an intermediate assessment after two weeks, a six-session intervention phase, and a post-intervention assessment. Our intervention applied two procedures. The first aimed at enhancing general composition abilities in terms of picking (P) ideas, organizing (O) notes, and writing (W) them down (POW), while the second specified the steps to write a persuasive text addressing a possible reader: a topic sentence (T), reasons (R), an explanation (E) for the reasons and the end of the sentence (E) (TREE). These procedures were termed POW + TREE. To analyze G’s texts, three types of measures were used by two raters at baseline, intermediate and post-test time: a) the presence of the TREE components; b) the quality of the reasons and explanations for the reasons; c) the number of mental state terms. All these measures showed relevant quantitative improvements, as well as qualitative changes. In addition, when G’s performance at the end of the intervention was compared to that of typically developing controls, no statistical difference appeared. The results are discussed in light of the potentialities offered by the type of intervention described here

The BepiColombo MORE gravimetry and rotation experiments with the ORBIT14 software

The BepiColombomission to Mercury is an ESA/JAXAcornerstone mission, consisting of two spacecraft in orbit around Mercury addressing several scientific issues. One spacecraft is the Mercury Planetary Orbiter, with full instrumentation to perform radio science experiments. Very precise radio tracking from Earth, on-board accelerometer and optical measurements will provide large data sets. From these it will be possible to study the global gravity field of Mercury and its tidal variations, its rotation state and the orbit of its centre of mass. With the gravity field and rotation state, it is possible to constrain the internal structure of the planet. With the orbit of Mercury, it is possible to constrain relativistic theories of gravitation. In order to assess that all the scientific goals are achievable with the required level of accuracy, full cycle numerical simulations of the radio science experiment have been performed. Simulated tracking, accelerometer and optical camera data have been generated, and a long list of variables including the spacecraft initial conditions, the accelerometer calibrations and the gravity field coefficients have been determined by a least-squares fit. The simulation results are encouraging: The experiments are feasible at the required level of accuracy provided that some critical terms in the accelerometer error are moderated. We will show that BepiColombo will be able to provide at least an order of magnitude improvement in the knowledge of Love number k2, libration amplitudes and obliquity, along with a gravity field determination up to degree 25 with a signal-to-noise ratio of 10

The radio science experiment with BepiColombo mission to Mercury

BepiColombo is a joint ESA/JAXA mission to Mercury with challenging objectives regarding geophysics, geodesy and fundamental physics. The Mercury Orbiter Radio science Experiment (MORE) is one of the on-board experiments, including three different but linked experiments: gravimetry, rotation and relativity. Using radio observables (range and range-rate) performed with very accurate tracking from ground stations, together with optical observations from the on-board high resolution camera (SIMBIO-SYS) and accelerometer readings from the on-board accelerometer (ISA), MORE will be able to measure with unprecedented accuracy the global gravity field of Mercury and the rotation state of the planet. In this work we present the results of a numerical full-cycle simulation of the gravimetry and rotation experiments of MORE: we discuss the accuracies which can be achieved, focussing in particular on the possible benefits from the use of optical observations in support to the tracking measurements

Bibliografia internacional de carrapato do bovino Boophilus microplus Canestrini, 1887 (Acarina: ixodidae).

Esta vasta coletânea bibliográfica sobre o carrapato do bovino mostra que muitos conhecimentos estão acumulados; por outro lado, a realidade da pecuária nacional é de carência de tecnologia para a solução deste problema. É, portanto, oportuno uma análise criteriosa dessas informações, e definir o caminho que deve ser seguido na busca de novos conhecimentos que possam ser transformados em tecnologia aplicada. Tecnologias essas adaptadas aos vários sistemas de criação com grande diversificação de raça e manejo, nas diferentes regiões do Brasil, que possam resultar em aumento da produtividade e produção, proporcionando maior rentabilidade aos produtores e preços do produto mais acessíveis aos consumidores, e excedentes para atender a necessidade de exportação. É uma obra com o objetivo de facilitar a todos aqueles que militam acreditando na solução deste problema, tendo como alvo, mais carne, leite e subprodutos para o bem-estar da sociedade humana e fonte de riqueza para o País. Além disso, resume e reflete a complexidade de disciplinas e segmentos da sociedade que, direta ou indiretamente, estão envolvidos em um problema que apresenta ser pequeno, mas que compromete muito um produto agropecuário. Por fim, registra-se o reconhecimento deste valioso trabalho prestado pelos autores Regina Célia Pisanelli e Gilson Pereira de Oliveira, que seguramente será muito útil para os estudiosos do problema do carrapato em prol da bovinocultura brasileira

Interaction of a short peptide with G-quadruplex-forming sequences: an SRCD and CD study

G-quadruplex (G4) forming DNA sequences were recently found to play a crucial role in the regulation of genomic processes such as replication, transcription and translation, also related to serious diseases. Therefore, systems capable of controlling DNA and RNA G-quadruplex structures would be useful for the modulation of various cellular events. In particular, peptides represent good candidates for targeting G-quadruplex structures, since they are easily tailored to enhance their functionality. In this work, we analyzed, by circular dichroism and synchrotron radiation circular dichroism spectroscopies, the interaction of a 25-residue peptide deriving from RHAU helicases (Rhau25) with three G-quadruplex-forming oligonucleotide sequences, in both sodium- and potassium-containing buffers, the most relevant monovalent cations in physiological conditions. The peptide displayed greater affinity for the G4 sequences adopting a parallel structure. However, it showed the ability to also interact with antiparallel or hybrid G-quadruplex structures, inducing a conformation conversion to the parallel structure. The stability of the oligonucleotide structure alone or in presence of the Rhau25 peptide was studied by temperature melting and UV denaturation experiments, and the data showed that the interaction with the peptide stabilized the conformation of oligonucleotide sequences when subjected to stress conditions

Social movements, the European crisis, and EU political opportunities

Social movements in the wake of the financial crisis have shifted from the counter-summits and world social forums of the global justice movement to the camps of the anti-austerity mobilizations, and from a clear focus on building ‘another Europe’ to more domestically embedded issues. Among other reasons, this turn away from the EU can be linked to contracting political opportunities for social justice movements at the European level. This article addresses the closure of opportunities at the EU level for the work of social movement groups campaigning on specific EU policies. We reflect on the complexity of the EU’s political opportunity structure prior to the financial crisis, before examining changes to the EU’s architecture effected through responses to the crises and outlining arguments on how EU level opportunities around socio-economic issues in particular have shrunk as a result. We then show how the perception of other political opportunities at the EU level is affected by the austerity response by drawing on campaigns that sought to exploit new opportunities included in the Lisbon Treaty and designed to increase citizens’ input. Opportunities introduced by changes made in the Lisbon Treaty are perceived through the prism of contracted opportunities flowing from power shifts caused by the response to the financial crisis

Operational experience, improvements, and performance of the CDF Run II silicon vertex detector

The Collider Detector at Fermilab (CDF) pursues a broad physics program at Fermilab's Tevatron collider. Between Run II commissioning in early 2001 and the end of operations in September 2011, the Tevatron delivered 12 fb-1 of integrated luminosity of p-pbar collisions at sqrt(s)=1.96 TeV. Many physics analyses undertaken by CDF require heavy flavor tagging with large charged particle tracking acceptance. To realize these goals, in 2001 CDF installed eight layers of silicon microstrip detectors around its interaction region. These detectors were designed for 2--5 years of operation, radiation doses up to 2 Mrad (0.02 Gy), and were expected to be replaced in 2004. The sensors were not replaced, and the Tevatron run was extended for several years beyond its design, exposing the sensors and electronics to much higher radiation doses than anticipated. In this paper we describe the operational challenges encountered over the past 10 years of running the CDF silicon detectors, the preventive measures undertaken, and the improvements made along the way to ensure their optimal performance for collecting high quality physics data. In addition, we describe the quantities and methods used to monitor radiation damage in the sensors for optimal performance and summarize the detector performance quantities important to CDF's physics program, including vertex resolution, heavy flavor tagging, and silicon vertex trigger performance.Comment: Preprint accepted for publication in Nuclear Instruments and Methods A (07/31/2013

Isolation of Flow and Nonflow Correlations by Two- and Four-Particle Cumulant Measurements of Azimuthal Harmonics in sNN=\sqrt{s_{_{\rm NN}}} = 200 GeV Au+Au Collisions

A data-driven method was applied to measurements of Au+Au collisions at $\sqrt{s_{_{\rm NN}}} =$ 200 GeV made with the STAR detector at RHIC to isolate pseudorapidity distance $\Delta\eta$-dependent and $\Delta\eta$-independent correlations by using two- and four-particle azimuthal cumulant measurements. We identified a component of the correlation that is $\Delta\eta$-independent, which is likely dominated by anisotropic flow and flow fluctuations. It was also found to be independent of $\eta$ within the measured range of pseudorapidity $|\eta|<1$. The relative flow fluctuation was found to be $34\% \pm 2\% (stat.) \pm 3\% (sys.)$ for particles of transverse momentum $p_{T}$ less than $2$ GeV/$c$. The $\Delta\eta$-dependent part may be attributed to nonflow correlations, and is found to be $5\% \pm 2\% (sys.)$ relative to the flow of the measured second harmonic cumulant at $|\Delta\eta| > 0.7$