30 research outputs found

    Causal Pathways for Small for Gestational Age Birth

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    Background: Small for Gestational Age (SGA) confers increased risk to the infant, and causal pathways are poorly understood. Objective: To develop and test a conceptual model for SGA, allowing us to distinguish causal pathways. Methods: This investigation used data on 2356 women from the “Prenatal Health Project” cohort. Associations between prenatal variables and SGA, both severe (\u3c3rd percentile) and moderate (3rd-10 percentile) were investigated using multinomial logistic regression models. Variables were entered according to our conceptual framework. Variable entry that attenuated beta values by \u3e10% indicated these variables might act along the same pathway. Results: The final models illustrated multiple pathways associated with SGA. Different pathways were associated with moderate or severe SGA. Smoking and preeclampsia related to separate pathways both associated with severe SGA. Gestational hypertension was associated with moderate SGA, possibly working through low placental weight. Conclusions: These results illustrated differing causal pathways, and suggest different underlying biological mechanisms

    Group entropies, correlation laws and zeta functions

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    The notion of group entropy is proposed. It enables to unify and generalize many different definitions of entropy known in the literature, as those of Boltzmann-Gibbs, Tsallis, Abe and Kaniadakis. Other new entropic functionals are presented, related to nontrivial correlation laws characterizing universality classes of systems out of equilibrium, when the dynamics is weakly chaotic. The associated thermostatistics are discussed. The mathematical structure underlying our construction is that of formal group theory, which provides the general structure of the correlations among particles and dictates the associated entropic functionals. As an example of application, the role of group entropies in information theory is illustrated and generalizations of the Kullback-Leibler divergence are proposed. A new connection between statistical mechanics and zeta functions is established. In particular, Tsallis entropy is related to the classical Riemann zeta function.Comment: to appear in Physical Review

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Multi-messenger Observations of a Binary Neutron Star Merger

    Get PDF
    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∌ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ÈŻ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∌ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∌10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∌ 9 and ∌ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

    The Cost-Effectiveness of Vaccination of Older Adults with an MF59-Adjuvanted Quadrivalent Influenza Vaccine Compared to Other Available Quadrivalent Vaccines in Germany

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    Enhanced quadrivalent influenza vaccines that include an adjuvant (aQIV) or a high dose of antigen (QIV-HD), which stimulate a stronger immune response in older adults than the standard vaccine (QIVe), are now approved. The objective of this research is to compare available vaccines and determine the cost-effectiveness of immunizing persons aged 65 years and above with aQIV compared to QIVe and QIV-HD in Germany. A compartmental transmission model calibrated to outpatient visits for influenza in Germany was used to predict the number of medically attended infections using the three vaccines. The rates of hospitalizations, deaths, and other economic consequences were estimated with a decision tree using German data where available. Based on meta-analysis, the rVE of −2.5% to 8.9% for aQIV versus QIV-HD, the vaccines are similar clinically, but aQIV is cost saving compared to QIV-HD (unit cost of EUR 40.55). All results were most sensitive to changes in vaccine effectiveness. aQIV may be cost-effective compared to QIVe depending on the willingness to pay for additional benefits in Germany. As aQIV and QIV-HD are similar in terms of effectiveness, aQIV is cost saving compared to QIV-HD at current unit prices

    Resource utilization and cost of treatment with anidulafungin or fluconazole for candidaemia and other forms of invasive candidiasis: focus on critically ill patients

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    Candidaemia and other forms of invasive candidiasis (C/IC) are serious and costly events for hospitalized patients, particularly those in the ICU. Both fluconazole and the echinocandins are recommended as first-line therapy for C/IC. Resource use and cost considerations are important in selecting appropriate treatment but little information is available on the economic implications of using echinocandins in this setting. To compare resource utilization and treatment costs (in US)associatedwiththeechinocandinanidulafungin(200mgintravenouslyonday1,then100mgintravenouslydaily)versusthoseoffluconazole(800mgintravenouslyonday1,then400mgintravenouslydaily)asfirst−linetreatmentforC/IC.AvailablechartsfrompatientsenrolledinarecentclinicaltrialcomparinganidulafunginandfluconazoleforC/ICwerereviewed.PatientswhowereintheICUatstudyentrywereidentified,andthefollowingdata,collectedduringthe13−weekstudyperiod,werecomparedbetweentreatmentgroups:globalresponseatendofstudytreatment,numberofdayspatientssurvivedafterhospitaldischarge(â€Čhospital−freeâ€Čdays),hospitalresourceuse,andC/IC−relatedcosts(year2008values)toaUShospitalpayer.Thesecomparisonswerealsoconductedforallnon−ICUhospitalizedpatients,andforsurvivorsinbothstudypopulations.SensitivityanalysesexploredthecostimpactofvariabilityinthehospitalizationcostsbetweenICUsandnon−ICUwardsandofreduceddurationintravenoustherapy.Statisticalcomparisonsbetweenthetwotreatmentgroupswereconductedforclinicaloutcomes,resourceuseandcostmeasures,usingregressionmodels.Allstatisticalcomparisonswereadjustedforbaselineco−variates(AcutePhysiologyandChronicHealthEvaluation[APACHE]IIscore,absoluteneutrophilcountandcatheterremovalstatus).ForICUpatientswithC/IC(n = 63),globalresponsewassignificantlyhigherforanidulafunginthanfluconazole(68.6US) associated with the echinocandin anidulafungin (200 mg intravenously on day 1, then 100 mg intravenously daily) versus those of fluconazole (800 mg intravenously on day 1, then 400 mg intravenously daily) as first-line treatment for C/IC. Available charts from patients enrolled in a recent clinical trial comparing anidulafungin and fluconazole for C/IC were reviewed. Patients who were in the ICU at study entry were identified, and the following data, collected during the 13-week study period, were compared between treatment groups: global response at end of study treatment, number of days patients survived after hospital discharge ('hospital-free' days), hospital resource use, and C/IC-related costs (year 2008 values) to a US hospital payer. These comparisons were also conducted for all non-ICU hospitalized patients, and for survivors in both study populations. Sensitivity analyses explored the cost impact of variability in the hospitalization costs between ICUs and non-ICU wards and of reduced duration intravenous therapy. Statistical comparisons between the two treatment groups were conducted for clinical outcomes, resource use and cost measures, using regression models. All statistical comparisons were adjusted for baseline co-variates (Acute Physiology and Chronic Health Evaluation [APACHE] II score, absolute neutrophil count and catheter removal status). For ICU patients with C/IC (n = 63), global response was significantly higher for anidulafungin than fluconazole (68.6% vs 42.9%; p = 0.03). ICU patients treated with anidulafungin had an average of 13.9 more hospital-free days (18.2 vs 4.3 days; p = 0.04) than those treated with fluconazole. After adjustment for co-variates, although lower costs were observed for anidulafungin vs fluconazole in ICU patients and in ICU patients who survived, no statistical differences were found. For all hospitalized patients (n = 159), global response was also higher for anidulafungin (78.3% vs 60.5%; p < 0.01). There was no difference in average length of hospitalization (29.6 days) or hospital-free days. After adjustment for co-variates, anidulafungin treatment resulted in an incremental C/IC-related cost of US2680 (p = 0.73). For hospitalized patients who survived (anidulafungin 81.9%, fluconazole 69.7%), anidulafungin treatment was associated with an incremental cost of $US231 (p = 0.98). Anidulafungin as first-line treatment of C/IC appears to be of particular benefit to ICU patients, improving clinical outcomes and possibly decreasing costs, driven by reduced ICU and hospital stay, when compared with fluconazole. Anidulafungin also yielded significantly improved treatment outcomes in the general inpatient population, with total costs similar to fluconazole
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