Towards Automated Real-Time Detection and Location of Large-Scale Landslides through Seismic Waveform Back Projection

Rainfall-triggered landslides are one of the most deadly natural hazards in many regions. Seismic recordings have been used to examine source mechanisms and to develop monitoring systems of landslides. We present a semiautomatic algorithm for detecting and locating landslide events using both broadband and short-period recordings and have successfully applied our system to landslides in Taiwan. Compared to local earthquake recordings, the recordings of landslides usually show longer durations and lack distinctive P and S wave arrivals; therefore, the back projection method is adopted for the landslide detection and location. To identify the potential landslide events, the seismic recordings are band-passed from 1 to 3 Hz and the spectrum pattern in the time-frequency domain is used to distinguish landslides from other types of seismic sources based upon carefully selected empirical criteria. Satellite images before and after the detected and located landslide events are used for final confirmation. Our landslide detection and spatial-temporal location system could potentially benefit the establishment of rainfall-triggered landslide forecast models and provide more reliable constraints for physics-based landslide modeling. The accumulating seismic recordings of landslide events could be used as a training dataset for machine learning techniques, which will allow us to fully automate our system in the near future

Factors driving the use of warfarin and non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

In the past, warfarin was the drug of choice for stroke prevention in patients with atrial fibrillation (AF). Recently, non-vitamin K antagonist oral anticoagulants (NOACs) have been approved as an alternative to warfarin in nonvalvular AF. However, there is a limited amount of real-world data on how NOACs are currently being used in Taiwan. This study was conducted to investigate the factors driving the initiation of anticoagulants and the selection of different anticoagulants in patients with AF. Methods: We used National Taiwan University Hospital's electronic database to identify all nonvalvular AF patients from January 1, 2007 to December 31, 2013. Multivariate logistic regression models were used to examine the factors driving the initiation of anticoagulants and the selection of different anticoagulants. Results: Among AF patients, 66.4% of anticoagulants users used NOACs instead of warfarin after the era of NOACs. Patients with female sex, hypertension, ischemic heart disease, cancer, hepatic disease, renal disease, bleeding history, and aspirin use were less likely to be anticoagulant users but are more likely to be anticoagulant users with a history of stroke (odds ratio = 2.64; 95% confidence interval, 2.02–3.45). Older age, ischemic heart disease, and aspirin use were the factors associated with NOACs usage, whereas hepatic disease showed the opposite results (odds ratio = 0.09; 95% confidence interval, 0.02–0.42). Conclusion: Stroke history was associated with anticoagulant use, whereas comorbidities associated with increased risk of bleeding showed the opposite result. Patients with hepatic disease were less likely to use NOACs

The Association between General Anesthesia and New Postoperative Uses of Sedative–Hypnotics: A Nationwide Matched Cohort Study

Sedative–hypnotic misuse is associated with psychiatric diseases and overdose deaths. It remains uncertain whether types of anesthesia affect the occurrence of new postoperative uses of sedative–hypnotics (NPUSH). We used reimbursement claims data of Taiwan’s National Health Insurance and conducted propensity score matching to compare the risk of NPUSH between general and neuraxial anesthesia among surgical patients who had no prescription of oral sedative–hypnotics or diagnosis of sleep disorders within the 12 months before surgery. The primary outcome was NPUSH within 180 days after surgery. Multivariable logistic regression models were used to calculate the adjusted odds ratio (aOR) and 95% confidence interval (CI). A total of 92,222 patients were evaluated after matching. Among them, 15,016 (16.3%) had NPUSH, and 2183 (4.7%) were made a concomitant diagnosis of sleep disorders. General anesthesia was significantly associated both with NPUSH (aOR: 1.17, 95% CI: 1.13–1.22, p < 0.0001) and NPUSH with sleep disorders (aOR: 1.11, 95% CI: 1.02–1.21, p = 0.0212) compared with neuraxial anesthesia. General anesthesia was also linked to NPUSH that occurred 90–180 days after surgery (aOR: 1.12, 95% CI: 1.06–1.19, p = 0.0002). Other risk factors for NPUSH were older age, female, lower insurance premium, orthopedic surgery, specific coexisting diseases (e.g., anxiety disorder), concurrent medications (e.g., systemic steroids), postoperative complications, perioperative blood transfusions, and admission to an intensive care unit. Patients undergoing general anesthesia had an increased risk of NPUSH compared with neuraxial anesthesia. This finding may provide an implication in risk stratification and prevention for sedative–hypnotic dependence after surgery