479 research outputs found

    Scale separation in granular packings: stress plateaus and fluctuations

    Full text link
    It is demonstrated, by numerical simulations of a 2D assembly of polydisperse disks, that there exists a range (plateau) of coarse graining scales for which the stress tensor field in a granular solid is nearly resolution independent, thereby enabling an `objective' definition of this field. Expectedly, it is not the mere size of the the system but the (related) magnitudes of the gradients that determine the widths of the plateaus. Ensemble averaging (even over `small' ensembles) extends the widths of the plateaus to sub-particle scales. The fluctuations within the ensemble are studied as well. Both the response to homogeneous forcing and to an external compressive localized load (and gravity) are studied. Implications to small solid systems and constitutive relations are briefly discussed.Comment: 4 pages, 4 figures, RevTeX 4, Minor corrections to match the published versio

    Dependent patients discharged home from PRM departments: relevant indicators

    Get PDF
    OBJECTIVE: To evaluate simple, measurable indicators of optimal organizational procedures for the hospital-to-home discharge of dependent patients.MATERIAL AND METHOD: All the general practitioners (GPs) in the Maine-et-Loire county of France were sent a questionnaire asking them to rank the three main criteria (from the most important to the least significant) from a list of 14. We analyzed the median ranking for each item and identified the most important items in terms of their relative frequency. RESULTS: The response rate was 10.77% (104 out of 966). Four criteria had a median score over 9: contact with the GP prior to discharge, informing the GP of the discharge date, training for the patient and his/her family in activities of daily living and providing a list of people to be contacted in the event of a problem at home. Respite hospitalization (in the event of difficulties at home) was cited as one of the three most relevant criteria. DISCUSSION-CONCLUSION: The criteria highlighted by the GPs were not highly specific for the discharge of a dependent patient. However, it would be interesting to extend this study by interviewing other stakeholders and determining whether these criteria indeed improve the organization of hospital-to-home discharge

    Influence of COVID-19 pandemic on decisions for the management of people with inflammatory rheumatic and musculoskeletal diseases: a survey among EULAR countries

    Get PDF
    Objectives: To investigate how the first wave of COVID-19 pandemic influenced decisions of rheumatologists and health professionals in rheumatology regarding the management of patients with inflammatory rheumatic and musculoskeletal diseases (RMDs). Methods: An English-language questionnaire was developed by a EULAR working group and distributed via national rheumatology societies of EULAR countries, EMEUNET and individual working group members. Responses were collected using an online survey tool. Descriptive statistics were calculated. Results: We analysed 1286 responses from 35/45 EULAR countries. Due to containment measures, 82% of respondents indicated cancellation/postponement of face-to-face visits of new patients (84% of them offering remote consultation) and 91% of follow-up visits (96% with remote consultation). The majority of respondents (58%) perceived that the interval between symptom onset and first rheumatological consultations was longer during containment restrictions than before. Treatment decisions were frequently postponed (34%), and the majority (74%) of respondents stated that it was less likely to start a biological disease modifying anti-rheumatic drug (DMARD)/targeted synthetic DMARD during the pandemic, mainly because of patients’ fear, limited availability of screening procedures and decreased availability of rheumatological services. Use of (hydroxy)chloroquine (HCQ) and tocilizumab (TCZ) for the COVID-19 indication was reported by 47% and 42% of respondents, respectively, leading to a shortage of these drugs for RMDs indications according to 49% and 14% of respondents, respectively. Conclusion: Measures related to containment of COVID-19 pandemic led to a perceived delay between symptom onset and a first rheumatological visit, postponement of treatment decisions, and shortage of HCQ and TCZ, thereby negatively impacting early treatment and treat-to-target strategies

    Internal states of model isotropic granular packings. III. Elastic properties

    Get PDF
    In this third and final paper of a series, elastic properties of numerically simulated isotropic packings of spherical beads assembled by different procedures and subjected to a varying confining pressure P are investigated. In addition P, which determines the stiffness of contacts by Hertz's law, elastic moduli are chiefly sensitive to the coordination number, the possible values of which are not necessarily correlated with the density. Comparisons of numerical and experimental results for glass beads in the 10kPa-10MPa range reveal similar differences between dry samples compacted by vibrations and lubricated packings. The greater stiffness of the latter, in spite of their lower density, can hence be attributed to a larger coordination number. Voigt and Reuss bounds bracket bulk modulus B accurately, but simple estimation schemes fail for shear modulus G, especially in poorly coordinated configurations under low P. Tenuous, fragile networks respond differently to changes in load direction, as compared to load intensity. The shear modulus, in poorly coordinated packings, tends to vary proportionally to the degree of force indeterminacy per unit volume. The elastic range extends to small strain intervals, in agreement with experimental observations. The origins of nonelastic response are discussed. We conclude that elastic moduli provide access to mechanically important information about coordination numbers, which escape direct measurement techniques, and indicate further perspectives.Comment: Published in Physical Review E 25 page

    Native drivers of fish life history traits are lost during the invasion process

    Get PDF
    © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Rapid adaptation to global change can counter vulnerability of species to population declines and extinction. Theoretically, under such circumstances both genetic variation and phenotypic plasticity can maintain population fitness, but empirical support for this is currently limited. Here, we aim to characterize the role of environmental and genetic diversity, and their prior evolutionary history (via haplogroup profiles) in shaping patterns of life history traits during biological invasion. Data were derived from both genetic and life history traits including a morphological analysis of 29 native and invasive populations of topmouth gudgeon Pseudorasbora parva coupled with climatic variables from each location. General additive models were constructed to explain distribution of somatic growth rate (SGR) data across native and invasive ranges, with model selection performed using Akaike's information criteria. Genetic and environmental drivers that structured the life history of populations in their native range were less influential in their invasive populations. For some vertebrates at least, fitness-related trait shifts do not seem to be dependent on the level of genetic diversity or haplogroup makeup of the initial introduced propagule, nor of the availability of local environmental conditions being similar to those experienced in their native range. As long as local conditions are not beyond the species physiological threshold, its local establishment and invasive potential are likely to be determined by local drivers, such as density-dependent effects linked to resource availability or to local biotic resistance

    EULAR provisional recommendations for the management of rheumatic and musculoskeletal diseases in the context of SARS-CoV-2

    Get PDF
    The provisional EULAR recommendations address several aspects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus, and the disease caused by SARS-CoV-2, COVID-19 and are meant for patients with rheumatic and musculoskeletal diseases (RMD) and their caregivers. A task force of 20 members was convened by EULAR that met several times by videoconferencing in April 2020. The task force finally agreed on five overarching principles and 13 recommendations covering four generic themes: (1) General measures and prevention of SARS-CoV-2 infection. (2) The management of RMD when local measures of social distancing are in effect. (3) The management of COVID-19 in the context of RMD. (4) The prevention of infections other than SARS-CoV-2. EULAR considers this set of recommendations as a 'living document' and a starting point, which will be updated as soon as promising new developments with potential impact on the care of patients with RMD become available

    Circulating adrenomedullin estimates survival and reversibility of organ failure in sepsis: the prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock-1 (AdrenOSS-1) study

    Get PDF
    Background: Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. Methods: AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. Results: Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p < 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM > 70 pg/ml upon admission than in those with bio-ADM ≤ 70 pg/ml. In patients with bio-ADM > 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). Conclusions: AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. Trial registration: ClinicalTrials.gov, NCT02393781. Registered on March 19, 2015
    • …
    corecore