The Strain Seismograms of P- and S-Waves of a Local Event Recorded by Four-Gauge Borehole Strainmeter

At a sampling rate of 100 samples per second, the YRY-4 four-gauge borehole strainmeters (FGBS) are capable of recording transient strains caused by seismic waves such as P and S waves or strain seismograms. At such a high sampling rate, data from the YRY-4 strainmeters demonstrate fairly satisfactory self-consistency. The strain tensor seismograms demonstrate the senses of motion of P waves, that is, the type of seismic wave travels in the direction of the maximum normal strain change. The observed strain patterns of S waves significantly differ from those of P waves and should contain information about the source mechanism. Spectrum analysis shows that the strain seismograms are consistent with conventional broadband seismograms from the same site

Relationship between Carotid Artery Sclerosis and Blood Pressure Variability in Essential Hypertension Patients

Objectives: This study aimed to investigate the relationship between the presence of carotid arteriosclerosis (CAS) and blood pressure variability (BPV) in patients with essential hypertension. Methods: One hundred and forty four essential hypertension patients underwent ambulatory BP monitoring for 24 hours after hospitalization. Common BPV metrics were calculated. General clinical parameters, including age, gender, height, weight, history of coronary heart disease, stroke, diabetes, hypertension, smoking and drink, were recorded. Biochemical indices were obtained from a blood test. Carotid intima-media thickness (IMT) and carotid plaques were assessed to separate patients into a non-CAS group (IMT≤0.9 mm; n=82) and a CAS group (IMT>0.9 mm; n=62). BPV metrics and clinical parameters were analyzed and compared between the two groups. Multivariate logistic regression analysis was performed to determine the associated risk factors of CAS. Results: Multivariate logistic regression analysis revealed that two BPV metrics, the standard deviation of daytime systolic blood pressure (SSD) (OR: 1.587, 95%CI: 1.242–2.028), the difference between average daytime SBP and nighttime SBP (OR: 0.914, 95%CI: 0.855-0.977), as well as three clinical parameters (age, OR: 1.098, 95%CI: 1.034-1.167; smoking, OR: 4.072, 95%CI: 1.466–11.310, and fasting blood glucose, OR: 2.029, 95%CI: 1.407–2.928), were significant factors of CAS in essential hypertension patients. Conclusion: SSD, in combination with the ageing, smoking and FBG, has been identified as risk factors for CAS in patients with essential hypertension