116 research outputs found

    Cucker–Smale Type Dynamics of Infinitely Many Individuals with Repulsive Forces

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    We study the existence and uniqueness of the time evolution of a system of infinitely many individuals, moving in a tunnel and subjected to a Cucker–Smale type alignment dynamics with compactly supported communication kernels and to short-range repulsive interactions to avoid collisions

    Particle Approximation of the BGK Equation

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    In this paper we prove the convergence of a suitable particle system towards the BGK model. More precisely, we consider an interacting stochastic particle system in which each particle can instantaneously thermalize locally. We show that, under a suitable scaling limit, propagation of chaos does hold and the one-particle distribution function converges to the solution of the BGK equation

    Non-mean-field Vicsek-type models for collective behavior

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    We consider interacting particle dynamics with Vicsek-type interactions, and their macroscopic Partial Differential Equation (PDE) limit, in the non-mean-field regime; that is, we consider the case in which each particle/agent in the system interacts only with a prescribed subset of the particles in the system (for example, those within a certain distance). In this non-mean-field regime the influence between agents (i.e. the interaction term) can be normalized either by the total number of agents in the system (global scaling) or by the number of agents with which the particle is effectively interacting (local scaling). We compare the behavior of the globally scaled and the locally scaled systems in many respects, considering for each scaling both the PDE and the corresponding particle model. In particular, we observe that both the locally and globally scaled particle system exhibit pattern formation (i.e. formation of traveling-wave-like solutions) within certain parameter regimes, and generally display similar dynamics. The same is not true of the corresponding PDE models. Indeed, while both PDE models have multiple stationary states, for the globally scaled PDE such (space-homogeneous) equilibria are unstable for certain parameter regimes, with the instability leading to traveling wave solutions, while they are always stable for the locally scaled one, which never produces traveling waves. This observation is based on a careful numerical study of the model, supported by further analysis

    Impaired circadian heart rate variability in Parkinson's disease: A time-domain analysis in ambulatory setting

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    Background: Heart rate variability (HRV) decreases in Parkinson's disease (PD) and it can be considered a marker for cardiovascular dysautonomia. The purpose of this pilot study is to evaluate long-term time-domain analysis of HRV of PD patients and compare the results with those of matched healthy individuals. Methods: Idiopathic PD patients without comorbidity impairing HRV, and age-matched healthy individuals were recruited in a pilot study. A long-term time domain analysis of HRV using 24-h ambulatory ECG was performed. Results: Overall, 18 PD patients fulfilling inclusion criteria completed the evaluation (mean age was 55.6 ± 8.8, disease duration: 5.0 ± 4.7). Mean SCOPA-AUT score was 10.1 ± 7.3. Patients were on Hoehn & Yahr stage 1-2 and mean Levodopa Equivalent Dose (LED) was 311 ± 239.9. Mean of the 5-min standard deviation (SD) of R-R intervals distribution (SDNN) for all 5 min segments of the entire recording (ISDNN) was significantly lower in patients compared to controls. ISDNN was significantly different between Parkinson's disease patients and healthy controls. Conclusions: In our population characterized by mild to moderate disease severity, time-domain assessment of HRV seemed to be a potential tool to characterize cardiovascular dysautonomia. Decrease of ISDNN in PD may reflect an autonomic derangement extending all day and night long

    Daya Tahan Spermatozoa Dalam Semen Cair Babi Landrace Pada Metode Penyimpanan Berbeda

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    Tujuan dilaksanakan penelitian ini untuk melihat pengaruh metode penyimpanan preservasi yang berbeda terhadap viabilitas spermatozoa semen babi landrace dalam pengencer alami air buah lontar (AL) dengan penambahan kuning telur ayam kampung (KT).  Semen diambil dari 5 ekor pejantan landrace yang telah dewasa kelamin. Setelah itu dilakukan pemeriksaan makros-mikros dari semen segar, semen dengan kriteria  motilitas , konsentrasi dan abnormalitas spermatozoa berturt-turut: >70%, >200 juta spermatozoa/ml, <20% yang layak untuk dijadikan semen cair. Perlakuan dalam penelitian:, P1(AL 95%+5% KT), P2(AL 85%+15% KT), P3(AL 75%+25% KT) yang simpan pada metode water jacket (WJ) dan P4(AL 95%+5% KT), P5(AL 85%+15% KT), P6(AL 75%+25% KT) yang disimpan dengan metode non water jacket (NWJ),  semen dikemas dalam mikrotube 1 ml dan disimpan pada suhu preservasi. Pada penelitian ini menunjukkan bahwa viabilitas spermatozooa dalam pengencer alami air buah lontar yang ditambahkan dengan kuning telur ayam kampung memperlihatkan hasil yang baik pada kombinasi AL 85% dan KT25% pada penyimpanan water jacket.  Semen cair pada pengencer kombinasi tersebut diatas mampu bertahan hingga 28 jam penyimpanan

    Is asthma control more than just an absence of symptoms? An expert consensus statement

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    Purpose: Definitions and measures of asthma control used in clinical trials and in clinical practice vary considerably. There is also misalignment between patients and healthcare professionals (HCPs) in terms of understanding and managing asthma control. This study aimed to progress towards a consensus definition of asthma control, and evaluate disparities between HCP and patient perspectives. Basic procedures: A two-stage Delphi questionnaire involving asthma specialists sought to identify areas of consensus on aspects of asthma control in clinical practice. Results were compared with those of a structured literature review to assess if existing guidance and measures of asthma control used in studies correlated with practice. Eighty-two panelists took part in the Delphi questionnaire. The structured literature review included 185 manuscripts and 31 abstracts. Main findings: Panelists agreed that there was no standard definition of asthma control, confirmed by a total of 19 different composite consensus/guideline definitions and/or validated measures of control being identified across the Delphi study and literature review. Panelists agreed on the positive associations of well-controlled asthma with patient outcomes, but not on the components or thresholds of a working definition of control. Principal conclusions: A universally accepted definition and measure of asthma control that is utilized and understood by patients, HCPs, and researchers is required

    Final report of EURAMET.M.G-K3 regional comparison of absolute gravimeters

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    The regional key comparison of absolute gravimeters, EURAMET.M.G-K3 and the simultaneously organized additional comparison, was held in Germany at the Geodetic Observatory Wettzell of the German Federal Agency for Cartography and Geodesy in the spring of 2018.Here we present the list of the participants who actually performed measurements during the comparison, the data submitted by the operators as well as the results of the determination of the gravity as a function of height at the comparison sites. The measurement strategy is briefly discussed and the results of the data harmonization is documented. Finally, the results of the constrained least squares adjustment are presented including the degrees of equivalence of each gravimeter and the key comparison reference values.Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).Export citation and abstract BibTeX RIS

    Evaluación del ISTH-BAT en los trastornos plaquetarios congénitos: correlación clínica, laboratorio y molecular

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    CO-153 Introducción: Los trastornos plaquetarios congénitos (TPC) son un grupo heterogéneo de enfermedades raras, que se clasifican en trombocitopenias hereditarias (THs) y en trombocitopatías hereditarias (TFPs). Su identificación inicial y su diagnóstico final son complejos. Éste, se basa en la la historia clínica, la exploración física, pruebas de laboratorio fenotípicas y la confirmación de la alteración molecular subyacente. Por otra parte, la valoración de la clínica hemorrágica suele ser subjetiva, por lo que la Sociedad Internacional de Trombosis y Hemostasia (ISTH) recomienda la utilización de escalas de sangrado (bleeding assessment tools, BAT). Los objetivos de nuestros estudios fueron a) evaluar la clínica hemorrágica con el ISTH-BAT en pacientes diagnosticados de TPC, b) su comparación entre THs y TFPs y c) su relación con las pruebas funcionales y moleculares. Métodos: Estudio retrospectivo de 138 pacientes con TPC incluidos en el proyecto nacional “Caracterización funcional y molecular de los TPC” de la SETH. La clínica hemorrágica se evaluó mediante el ISTHBAT, obteniendo un score de sangrado (BS). El diagnóstico fenotípico se realizó mediante hemograma y frotis de sangre periférica, la función plaquetaria mediante agregometría de transmisión de luz (LTA) y citometría de flujo (CMF) y el diagnóstico molecular mediante secuenciación ..
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