105 research outputs found

    Hydrodynamic Synchronisation of Model Microswimmers

    Full text link
    We define a model microswimmer with a variable cycle time, thus allowing the possibility of phase locking driven by hydrodynamic interactions between swimmers. We find that, for extensile or contractile swimmers, phase locking does occur, with the relative phase of the two swimmers being, in general, close to 0 or pi, depending on their relative position and orientation. We show that, as expected on grounds of symmetry, self T-dual swimmers, which are time-reversal covariant, do not phase-lock. We also discuss the phase behaviour of a line of tethered swimmers, or pumps. These show oscillations in their relative phases reminiscent of the metachronal waves of cilia.Comment: 17 pages, 8 figure

    Modelling of strain effects in manganite films

    Full text link
    Thickness dependence and strain effects in films of La1−xAxMnO3La_{1-x}A_xMnO_3 perovskites are analyzed in the colossal magnetoresistance regime. The calculations are based on a generalization of a variational approach previously proposed for the study of manganite bulk. It is found that a reduction in the thickness of the film causes a decrease of critical temperature and magnetization, and an increase of resistivity at low temperatures. The strain is introduced through the modifications of in-plane and out-of-plane electron hopping amplitudes due to substrate-induced distortions of the film unit cell. The strain effects on the transition temperature and transport properties are in good agreement with experimental data only if the dependence of the hopping matrix elements on the Mn−O−MnMn-O-Mn bond angle is properly taken into account. Finally variations of the electron-phonon coupling linked to the presence of strain turn out important in influencing the balance of coexisting phases in the filmComment: 7 figures. To be published on Physical Review

    Towards optimal use of antithrombotic therapy of people with cancer at the end of life: a research protocol for the development and implementation of the SERENITY shared decision support tool Thrombosis Research

    Get PDF
    Background: Even though antithrombotic therapy has probably little or even negative effects on the well-being of people with cancer during their last year of life, deprescribing antithrombotic therapy at the end of life is rare in practice. It is often continued until death, possibly resulting in excess bleeding, an increased disease burden and higher healthcare costs. Methods: The SERENITY consortium comprises researchers and clinicians from eight European countries with specialties in different clinical fields, epidemiology and psychology. SERENITY will use a comprehensive approach combining a realist review, flash mob research, epidemiological studies, and qualitative interviews. The results of these studies will be used in a Delphi process to reach a consensus on the optimal design of the shared decision support tool. Next, the shared decision support tool will be tested in a randomised controlled trial. A targeted implementation and dissemination plan will be developed to enable the use of the SERENITY tool across Europe, as well as its incorporation in clinical guidelines and policies. The entire project is funded by Horizon Europe.Results: SERENITY will develop an information-driven shared decision support tool that will facilitate treatment decisions regarding the appropriate use of antithrombotic therapy in people with cancer at the end of life. Conclusions: We aim to develop an intervention that guides the appropriate use of antithrombotic therapy, prevents bleeding complications, and saves healthcare costs. Hopefully, usage of the tool leads to enhanced empowerment and improved quality of life and treatment satisfaction of people with advanced cancer and their care givers

    A Pre-Landing Assessment of Regolith Properties at the InSight Landing Site

    Get PDF
    This article discusses relevant physical properties of the regolith at the Mars InSight landing site as understood prior to landing of the spacecraft. InSight will land in the northern lowland plains of Mars, close to the equator, where the regolith is estimated to be ≄3--5 m thick. These investigations of physical properties have relied on data collected from Mars orbital measurements, previously collected lander and rover data, results of studies of data and samples from Apollo lunar missions, laboratory measurements on regolith simulants, and theoretical studies. The investigations include changes in properties with depth and temperature. Mechanical properties investigated include density, grain-size distribution, cohesion, and angle of internal friction. Thermophysical properties include thermal inertia, surface emissivity and albedo, thermal conductivity and diffusivity, and specific heat. Regolith elastic properties not only include parameters that control seismic wave velocities in the immediate vicinity of the Insight lander but also coupling of the lander and other potential noise sources to the InSight broadband seismometer. The related properties include Poisson’s ratio, P- and S-wave velocities, Young’s modulus, and seismic attenuation. Finally, mass diffusivity was investigated to estimate gas movements in the regolith driven by atmospheric pressure changes. Physical properties presented here are all to some degree speculative. However, they form a basis for interpretation of the early data to be returned from the InSight mission.Additional co-authors: Nick Teanby and Sharon Keda

    Fauna of euglossina (Hymenoptera: Apidae) from southwestern Amazonia, Acre, Brazil

    Get PDF
    Male orchid bees were collected between December 2005 and September 2006 in 11 forest areas of different sizes in the region of Rio Branco, Acre, Southwestern Amazonia, Brazil. The bees were attracted by 6 aromatic compounds and collected by insect nets and scent baited traps. A total of 3,675 males of Euglossina in 4 genera and 36 species were collected. Eulaema cingulata (Fabricius) was the most common (24.6%), followed by Eulaema meriana (Olivier) (14.6%), Euglossa amazonica Dressler (10.5%), Eulaema nigrita Lepeletier (10.5%) and Eulaema pseudocingulata (Oliveira) (7.2%). Cineole was the scent that attracted the greatest number of individuals (23.8%) and methyl salicylate the greatest number of species (28) for both methods of sampling. Thirty one bees of 9 species with pollinar orchid attached to their bodies were collected. The accumulative number of species stabilized after the 48th collection. Few species were abundant; the great majority were represented by less than 50 bees. The lack of standardized sample protocols limited very much the conclusions derived from comparisons among the majority of studies on Euglossina assemblages. However, the results presented here suggest that the State of Acre is very rich in those bees compared to other regions.Machos de abelhas Euglossina foram coletados entre dezembro de 2005 e setembro de 2006 em 11 ĂĄreas florestais de diferentes tamanhos na regiĂŁo de Rio Branco, Acre, AmazĂŽnia Sul-Ocidental. As abelhas foram atraĂ­das por 6 substĂąncias odorĂ­feras e coletadas com rede entomolĂłgica e armadilhas. Um total de 3.675 machos de Euglossina pertencentes a 4 gĂȘneros e 36 espĂ©cies foi coletado. Eulaema cingulata (Fabricius) foi a espĂ©cie mais comum (24,6%), seguida por Eulaema meriana (Olivier) (14,6%), Euglossa amazonica Dressler (10,5%), Eulaema nigrita Lepeletier (10,5%) e Eulaema pseudocingulata (Oliveira) (7,2%). Cineol foi a substĂąncia que atraiu maior nĂșmero de indivĂ­duos (23,8%) e metil salicilato o maior nĂșmero de espĂ©cies (28) para ambos os mĂ©todos de coleta. Foram coletados 31 indivĂ­duos pertencentes a 9 espĂ©cies portando polinĂĄrios. O nĂșmero acumulado de espĂ©cies coletadas na regiĂŁo estabilizou a partir da 48ÂȘ coleta. Poucas espĂ©cies foram abundantes, a maioria representada por menos que 50 indivĂ­duos. A falta de um protocolo amostral padronizado tem limitado comparaçÔes entre trabalhos realizados em diferentes regiĂ”es. Contudo, os resultados aqui apresentados indicam que o Acre apresenta elevada riqueza dessas abelhas

    Precision Measurement of the Proton Flux in Primary Cosmic Rays from Rigidity 1 GV to 1.8 TV with the Alpha Magnetic Spectrometer on the International Space Station

    Get PDF
    A precise measurement of the proton flux in primary cosmic rays with rigidity (momentum/charge) from 1 GV to 1.8 TV is presented based on 300 million events. Knowledge of the rigidity dependence of the proton flux is important in understanding the origin, acceleration, and propagation of cosmic rays. We present the detailed variation with rigidity of the flux spectral index for the first time. The spectral index progressively hardens at high rigidities.</p

    Synovial sarcoma of the hypopharynx in a pediatric patient: Case report

    Get PDF
    Introduction: Synovial sarcoma (SS) is uncommon high grade soft tissue sarcoma, accounting for less than 10% of all head and neck sarcomas. Also, about 10% of SS occur within the Head & Neck. In the pediatric population, SS is an extremely rare head & neck malignancy. Presentation of case: We present a case of sixteen years old boy diagnosed with SS situated of the hypopharynx treated by surgical excision and post operative radio-chemotherapy. Discussion: This anatomical location brings additional functional challenges (swallowing, phonation, respiration), especially in the pediatric population. Pre-operative and even post-operative histopathological diagnosis of SS remains difficult. Optimal treatment of Head & Neck SS has to balance functional and oncologic aspects. Conclusion: SS is an extremely rare head & neck malignancy in pediatric population. It has multifaceted challenges including pre and post-operative histopathological diagnosis and optimal modality of treatment. Clinical judgment, especially in the pediatric population, needs to balance tumor free margins and organ preservation in head and neck region

    Finite-state Controllers of POMDPs via Parameter Synthesis

    Get PDF
    Contains fulltext : 199869.pdf (preprint version ) (Open Access)Uncertainty in Artificial Intelligence: Thirty-Fourth Conference (2018) August 6-10, 2018, Monterey, California, US
    • 

    corecore