Homogeneous transit timing analyses of ten exoplanet systems

We study the transit timings of 10 exoplanets in order to investigate potential transit timing variations in them. We model their available ground-based light curves, some presented here and others taken from the literature, and homogeneously measure the mid-transit times. We statistically compare our results with published values and find that the measurement errors agree. However, in terms of recovering the possible frequencies, homogeneous sets can be found to be more useful, of which no statistically relevant example has been found for the planets in our study. We corrected the ephemeris information of all 10 planets we studied and provide these most precise light elements as references for future transit observations with space-borne and ground-based instruments. We found no evidence for secular or periodic changes in the orbital periods of the planets in our sample, including the ultra-short period WASP-103 b, whose orbit is expected to decay on an observable time-scale. Therefore, we derive the lower limits for the reduced tidal quality factors (Q(*)') for the host stars based on best-fitting quadratic functions to their timing data. We also present a global model of all available data for WASP-74 b, which has a Gaia parallax-based distance value similar to 25 per cent larger than the published value

Prediction compressive strength of cement-based mortar containing metakaolin using explainable Categorical Gradient Boosting model

Although machine learning models have been employed for the compressive strength (CS) of cement-based mortar containing metakaolin, it is difficult to understand how they work due to “black-box” nature. In order to explain the involved mechanism, Categorical Gradient Boosting (CatBoost) model with feature importance, feature interaction, partial dependence plot (PDP) and SHapley Additive exPlanations (SHAP) is proposed in this paper. A dataset consisting of 424 samples with six input variables is used to build the CatBoost model, which has optimal performance by tuning a set of seven hyper-parameters using sequential model-based optimization. Five quantitative measures (R2, MAE, RMSE, a10-, a20-index) are employed to evaluate the accuracy and the obtained results are superior to the previous study. It is from feature importance that the most significant input variable involving the CS is water-to-binder ratio, followed by age of specimen and cement grade. The strongest feature interaction is between water-to-binder ratio and metakaolin. A comprehensive parametric study is carried out via SHAP and PDP to investigate the effects of all input variables on the CS of cement-based mortar

Stroke incidence and outcomes in northeastern greece the evros stroke registry

Background and Purpose-Data are scarce on both stroke incidence rates and outcomes in Greece and in rural areas in particular. We performed a prospective population-based study evaluating the incidence of frst-ever stroke in the Evros prefecture, a region of a total 147 947 residents located in North Eastern Greece. Methods-Adult patients with frst-ever stroke were registered during a 24-month period (2010-2012) and followed up for 12 months. To compare our stroke incidence with that observed in other studies, we standardized our incidence rate data according to the European Standard Population, World Health Organization, and Segi population. We also applied criteria of data quality proposed by the Monitoring Trends and Determinants in Cardiovascular Disease project. Stroke diagnosis and classifcation were performed using World Health Organization criteria on the basis of neuroimaging and autopsy data. Results-We prospectively documented 703 stroke cases (mean age: 75±12 years; 52.8% men; ischemic stroke: 80.8%; intracerebral hemorrhage: 11.8%; subarachnoid hemorrhage: 4.4%; undefned: 3.0%) with a total follow-up time of 119805 person-years. The unadjusted and European Standard Population-adjusted incidences of all strokes were 586.8 (95% confdence interval [CI], 543.4-630.2) and 534.1 (95% CI, 494.6-573.6) per 100000 person-years, respectively. The unadjusted incidence rates for ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage were 474.1 (95% CI, 435-513), 69.3 (95% CI, 54-84), and 25.9 (95% CI, 17-35) per 100000 person-years, respectively. The corresponding European Standard Population-adjusted incidence rates per 100000 person-years were 425.9 (95% CI, 390.9-460.9), 63.3 (95% CI, 49.7-76.9), and 25.8 (95% CI, 16.7-34.9) for ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage, respectively. The overall 28-day case fatality rate was 21.3% (95% CI, 18.3%-24.4%) for all strokes and was higher in hemorrhagic strokes than ischemic stroke (40.4%, 95% CI, 31.3%-49.4% versus 16.2%, 95% CI, 13.2%-19.2%). Conclusions-This is the largest to date population-based study in Greece documenting one of the highest stroke incidences ever reported in South Europe, highlighting the need for effcient stroke prevention and treatment strategies in Northeastern Greece. © 2018 American Heart Association, Inc

High-Resolution Free-Breathing Automated Quantitative Myocardial Perfusion by Cardiovascular Magnetic Resonance for the Detection of Functionally Significant Coronary Artery Disease

Aims: Current assessment of myocardial ischaemia from stress perfusion cardiovascular magnetic resonance (SP-CMR) largely relies on visual interpretation. This study investigated the use of high-resolution free-breathing SP-CMR with automated quantitative mapping in the diagnosis of coronary artery disease (CAD). Diagnostic performance was evaluated against invasive coronary angiography (ICA) with fractional flow reserve (FFR) measurement.Methods and results: Seven hundred and three patients were recruited for SP-CMR using the research sequence at 3 Tesla. Of those receiving ICA within 6 months, 80 patients had either FFR measurement or identification of a chronic total occlusion (CTO) with inducible perfusion defects seen on SP-CMR. Myocardial blood flow (MBF) maps were automatically generated in-line on the scanner following image acquisition at hyperaemic stress and rest, allowing myocardial perfusion reserve (MPR) calculation. Seventy-five coronary vessels assessed by FFR and 28 vessels with CTO were evaluated at both segmental and coronary territory level. Coronary territory stress MBF and MPR were reduced in FFR-positive (≤0.80) regions [median stress MBF: 1.74 (0.90–2.17) mL/min/g; MPR: 1.67 (1.10–1.89)] compared with FFR-negative regions [stress MBF: 2.50 (2.15–2.95) mL/min/g; MPR 2.35 (2.06–2.54) P &lt; 0.001 for both]. Stress MBF ≤ 1.94 mL/min/g and MPR ≤ 1.97 accurately detected FFR-positive CAD on a per-vessel basis (area under the curve: 0.85 and 0.96, respectively; P &lt; 0.001 for both). Conclusion: A novel scanner-integrated high-resolution free-breathing SP-CMR sequence with automated in-line perfusion mapping is presented which accurately detects functionally significant CAD.</div