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Neighbourhood green space and mental health:the moderating role of socio-economic status
No full textDiscontinuous stochastic forcing in Greenland ice core data
No full textPaleoclimate proxy records from Greenland ice cores, archiving e.g. δ¹⁸O as a proxy for surface temperature, show that sudden climatic shifts called Dansgaard–Oeschger events (DO) occurred repeatedly during the last glacial interval. They comprised substantial warming of the Arctic region from cold to milder conditions. Concomitant abrupt changes in the dust concentrations of the same ice cores suggest that sudden reorganisations of the hemispheric-scale atmospheric circulation have accompanied the warming events. Genuine bistability of the North Atlantic climate system is commonly hypothesised to explain the existence of stadial (cold) and interstadial (milder) periods in Greenland. However, the physical mechanisms that drove abrupt transitions from the stadial to the interstadial state, and more gradual yet still abrupt reverse transitions, remain debated. Here, we conduct a one-dimensional data-driven analysis of the Greenland temperature and atmospheric circulation proxies under the purview of stochastic processes. We take the Kramers–Moyal equation to estimate each proxy’s drift and diffusion terms within a Markovian model framework. We then assess noise contributions beyond Gaussian white noise. The resulting stochastic differential equation (SDE) models feature a monostable drift for the Greenland temperature proxy and a bistable one for the atmospheric circulation proxy. Indicators of discontinuity in stochastic processes suggest to include higher-order terms of the Kramers–Moyal equation when modelling the Greenland temperature proxy’s evolution. This constitutes a qualitative difference in the characteristics of the two time series, which should be further investigated from the standpoint of climate dynamics
Determinants of adherence to the Mediterranean diet among adults in Mediterranean countries:a systematic literature review
No full textEarlier de-isolation of SARS-CoV-2-infected ICU patients using a novel viability PCR:a prospective cohort study
No full textUNLABELLED: Intensive care unit (ICU) patients with COVID-19 are isolated until two subsequent SARS-CoV-2 PCR tests have become negative. The question is whether the viral RNA detected here represents intact or compromised viral particles. A viability PCR method detects only intact infectious viruses and disregards RNA from incomplete non-infectious viruses or RNA remnants. We hypothesize that the time to a negative PCR is shorter using the viability PCR compared to conventional SARS-CoV-2 PCR. Patients admitted to the ICU in the Maastricht University Medical Center within an ongoing prospective cohort were included, and respiratory samples were collected three times weekly. Samples were aliquoted for viability PCR into two aliquots, one of which was treated with propidium monoazide (PMA) to eliminate incomplete viruses. The PMA-untreated sample corresponded to the traditional SARS-CoV-2 PCR used in routine diagnostics. A mean time difference between viability and conventional PCR was estimated, assuming a negative binomial distribution. One hundred two ICU patients were included in the analysis. The time to a negative PCR test result differed significantly between viability PCR and conventional PCR (Paired Prentice-Wilcoxon test P-value = 0.0001). On average, the first negative viability PCR test result occurred 2.4 days (95% CI 1.5-4.2) before the first negative conventional PCR test result. The application of a viability PCR technique for SARS-CoV-2 provided an earlier indication of the absence of intact virus, suggesting reduced infectivity, potentially enabling earlier de-isolation of ICU patients. IMPORTANCE: This study demonstrated that, within patients, on average, viability PCR became negative 2.4 days earlier than conventional PCR, indicating that viability PCR could potentially assist in de-isolating patients 2.4 days earlier. Future use of this assay could thus aid in improving routine COVID-19 diagnostics and prognostics related to the timing of de-isolation. Additionally, future development of a similar approach for other respiratory viruses could be of interest.</p
