Do geomagnetic disturbances of solar origin affect arterial blood pressure?

OBJECTIVE: Episodic reports suggest that geomagnetic disturbances of solar origin are associated with biological and clinical events, including increased arterial blood pressure (BP). We reassessed this aspect by relating solar activity levels to ambulatory BP measured in our out-patient population. PATIENTS AND METHODS: The ambulatory BP measurements of 447 consecutive untreated patients attending a hypertension out-patient clinic who did a monitoring for diagnostic purposes over 5 years were retrieved. The mean daytime, night-time and 24-h BP and heart rate values were related to the temporally corresponding geomagnetic index k-sum obtained by the nearest observatory. K-sum is a local measurement of the irregular disturbances of the geomagnetic field caused by solar particle radiation. RESULTS: Significant to highly significant positive correlations were observed for k-sum with systolic (daytime and 24 h) and diastolic BP (daytime, night-time and 24 h), but not with heart rate. No correlations were found with the k-sum of 1 or 2 days before the monitorings. Multiple correlations which also included other potential confounding factors (date, age) confirmed a significant effect of k-sum on BP. Comparison made in season-matched subgroups of quiet and disturbed days (using three different criteria of definition), always showed significantly higher values in the disturbed days for all BP parameters except systolic night-time pressure. The difference between the quietest and the most disturbed days was of about 6 to 8 mm Hg for 24-h systolic and diastolic BP. CONCLUSION: These results are unlikely to be due to unrelated secular trends, but seem to reflect a real relation between magnetic field disturbances and BP.     

Comparison of 802.11ah,BLE and 802.15.4 for a Home Automation Use Case

Understanding the main short-range wireless technologies operating in unlicensed bands is an important step before deploying Internet of Things (IoT) applications. In this study, we have selected IEEE 802.11ah, Bluetooth Low Energy and IEEE 802.15.4 for performance comparison in terms of delay, service ratio, traffic loss, activity factor and battery lifetime in a home automation scenario. Also, a low overhead protocol stack suitable for IoT applications is considered. The analysis takes into account heterogeneous devices and different traffic loads. The results show advantages and disadvantages with respect to the different performance indicators with generally satisfactory behavior for the three technologies. Among them, BLE is recognized as the most suitable candidate technology for the home automation domain.     

Anticoagulation,delivered dose and outcomes in CRRT: The program to improve care in acute renal disease (PICARD)

Delivered dialysis dose by continuous renal replacement therapies (CRRT) depends on circuit efficacy, which is influenced in part by the anticoagulation strategy. We evaluated the association of anticoagulation strategy used on solute clearance efficacy, circuit longevity, bleeding complications, and mortality. We analyzed data from 1740 sessions 24 h in length among 244 critically ill patients, with at least 48 h on CRRT. Regional citrate, heparin, or saline flushes was variably used to prevent or attenuate filter clotting. We calculated delivered dose using the standardized Kt/V_urea. We monitored filter efficacy by calculating effluent urea nitrogen/blood urea nitrogen ratios. Filter longevity was significantly higher with citrate (median 48, interquartile range [IQR] 20.3–75.0 hours) than with heparin (5.9, IQR 8.5–27.0 hours) or no anticoagulation (17.5, IQR 9.5–32 hours, P < 0.0001). Delivered dose was highest in treatments where citrate was employed. Bleeding complications were similar across the three groups (P = 0.25). Compared with no anticoagulation, odds of death was higher with the heparin use (odds ratio [OR] 1.82, 95% confidence interval [CI] 1.02–3.32; P = 0.033), but not with citrate (OR 1.02 95% CI 0.54–1.96; P = 0.53). Relative to heparin or no anticoagulation, the use of regional citrate for anticoagulation in CRRT was associated with significantly prolonged filter life and increased filter efficacy with respect to delivered dialysis dose. Rates of bleeding complications, transfusions, and mortality were similar across the three groups. While these and other data suggest that citrate anticoagulation may offer superior technical performance than heparin or no anticoagulation, adequately powered clinical trials comparing alternative anticoagulation strategies should be performed to evaluate overall safety and efficacy.     

Application of Central Composite Design to evaluate the antilisterial activity of hydro-alcohol berry extract of Myrtus communis L.

The antimicrobial activity of the hydro-alcohol extract of Myrtus communis L. (ME) berries was investigated against six Listeria monocytogenes strains (2 type strains and 4 isolates). Sub-lethal ME concentrations reduced L. monocytogenes counts by at least 2 log cycles. A Central Composite Design was used to investigate the combined effects of sub-lethal concentrations of ME (0.039–0.195 mL/100 mL), NaCl (0–2.0 g/100 mL) and pH (5.0–7.0) on strains growth. ME affected growth parameters, generally extending lag phase length and reducing maximum growth, sometimes with interactive effects with pH. The highest ME concentrations (0.117–0.195 mL/100 mL) combined with the lowest pH values (5.0–6.0) strongly reduced or even inhibited strains growth.     

Statistical analyses of inherent variability of soil strength and effects on engineering geology design

Clayey soil strata, as all natural deposits, generally show variability in the values of their geotechnical properties. This is due mainly to geological and environmental processes such as deposition and diagenesis, which introduce heterogeneity, anisotropy and variability to soil properties. Other causes of variability, and thus uncertainty, are the representativeness of samples and errors related to testing procedure, measurement and data processing procedures. To improve our knowledge about the inherent variability in the geomechanical properties of clays, this work presents a case study related to the analysis of the strength variability along a log of marine stiff clay deposits, which are apparently quite homogeneous. The analysis was based on pocket penetrometer strength measurement, performed both punctually and across the whole deposit. The adopted testing procedure, which is fast and reliable, provides a really wide dataset of the investigated soil property, with more than 800 data points. These allow for detailed variability analysis, and a reliable estimation of the coefficient of variation as well as research into the best fitting probability density functions, which are key factors for robust design. The presented case study allows discussion of the inherent variability of soil properties, and its influence on the characteristic values of soil strength in geotechnical design.