Dependence Types in a Binarized Precipitation Network

2021 ◽  
Author(s):  
Viola Meroni ◽  
Carlo De Michele ◽  
Leila Rahimi ◽  
Cristina Deidda ◽  
Antonio Ghezzi
Keyword(s):  
Confidence Interval ◽  
North Africa ◽  
Lag Time ◽  
Rain Gauges ◽  
Different Types ◽  
Precipitation Network ◽  
Sample Estimate

<p>In a network of binarized precipitation (i.e., wet or dry value), the connection or dependence between each pair of nodes can occur following one or more of the following conditions: wet‐wet, dry‐dry, wet‐dry, or dry‐wet. Here, we firstly investigate the different types of dependence, year by year, within a precipitation network of binarized variables. We compare the sample estimate of the probability of co‐occurrence (or occurrence with a lag time within ±3 days) of each of the four possible combinations with respect to the correspondent confidence interval in hypothesis of independence. We develop a procedure to efficiently assess the dependence behavior of all couples of nodes within the network and apply the methodology to a network of rain gauges covering Europe and north Africa.</p>

Abstract WP347: Clopidogrel Plus Aspirin in Patients With Different Types of Single Small Subcortical Infarction_Subgroup Analysis of CHANCE Trial

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Yilong Wang ◽  
Xiaomeng Yang ◽  
Jing Jing ◽  
Xingquan Zhao ◽  
Liping Liu ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Recurrent Stroke ◽  
Final Analysis ◽  
Hazard Ratio ◽  
Adjusted Hazard Ratio ◽  
Parent Artery ◽  
Bleeding Events ◽  
Intention To Treat ◽  
Different Types ◽  
Aspirin Group

Objective: We aim to investigate the effects and safety of clopidogrel plus aspirin in patients with different types of single small subcortical infarction(SSSI) in the Clopidogrel in High-risk patients with Acute Non-disabling Cerebrovascular Events (CHANCE) trial. Methods: In this subgroup analysis, SSSI was defined as single DWI lesion of ≤2.0 cm and SSSI with stenosis of any degree of the parent artery was regarded as a SSSI+PAD. We assessed the interaction of the treatment effects of clopidogrel plus aspirin versus aspirin alone among patients with and without PAD. Efficacy was assessed by intention to treat analysis and safety was assessed in the on-treatment population. Results: A total of 338 patients with SSSI were included in the final analysis,105 with SSSI+PAD and 233 SSSI-PAD. In SSSI+PAD patients, 10.9% (5/46) had recurrent stroke in the clopidogrel-aspirin group as compared to 13.6% (8/59) in the aspirin group (adjusted hazard ratio, 0.66; 95% confidence interval, 0.20-2.20; P=0.50). In SSSI-PAD patients, 8.9% (11/124) had recurrent stroke in the clopidogrel-aspirin group as compared 7.3% (8/109) in the aspirin group (adjusted hazard ratio, 1.64; 95% confidence interval, 0.61- 4.38; P=0.32). The number of bleeding events was similar between the clopidogrel-aspirin group and aspirin group regardless of SSSI+PAD or SSSI-PAD. Conclusions: Although dual antiplatelet therapy did not significantly reduce the risk of recurrent stroke than aspirin alone in patients with SSSI. It was potentially beneficial to the patients with SSSI+PAD. Dual antiplatelet treatment did not increase the risk of bleeding in patients with any kind of SSSI.

scholarly journals At-site and regional frequency analysis of extreme precipitation from radar-based estimates

2017 ◽  
Author(s):  
Edouard Goudenhoofdt ◽  
Laurent Delobbe ◽  
Patrick Willems
Keyword(s):  
Confidence Interval ◽  
Frequency Analysis ◽  
Extreme Precipitation ◽  
Rain Gauge ◽  
Regional Frequency Analysis ◽  
Extreme Value Analysis ◽  
Value Analysis ◽  
Rain Gauges ◽  
Rainfall Extremes ◽  
Regional Frequency

Abstract. In Belgium, only rain gauge time-series have been used so far to study extreme precipitation at a given location. In this paper, the potential of a 12-year quantitative precipitation estimation (QPE) from a single weather radar is evaluated. For the period 2005–2016, independent sliding 1 h and 24 h rainfall extremes from automatic rain gauges and collocated radar estimates are compared. The extremes are fitted to the exponential distribution using regression in QQ-plots with a threshold rank which minimises the mean squared error. A basic radar product used as reference exhibits unrealistic high extremes and is not suitable for extreme value analysis. For 24 h rainfall extremes, which occur partly in winter, the radar-based QPE needs a bias correction. A few missing events are caused by the wind drift of convective cells and strong radar signal attenuation. Differences between radar and gauge values are caused by spatial and temporal sampling, gauge rainfall underestimations and radar errors due to the relation between reflectivity and rain rate. Nonetheless the fit to the QPE data is within the confidence interval of the gauge fit, which remains large due to the short study period. A regional frequency analysis is performed on radar data within 20 km of the locations of 4 rain gauges with records from 1965 to 2008. Assuming that the extremes are correlated within the region, the fit to the two closest rain gauge data is within the confidence interval of the radar fit, which is small due to the sample size. In Brussels, the extremes on the period 1965–2008 from a rain gauge are significantly lower than the extremes from an automatic gauge and the radar on the period 2005–2016. For 1 h duration, the location parameter varies slightly with topography and the scale parameter exhibits some variations from region to region. The radar-based extreme value analysis can be extended to other durations.

Pottery finds from Hermitage EE.50 in Naqlun: preliminary assessment of the assemblage

2018 ◽  
Vol 26 (1) ◽  
pp. 171-182
Author(s):  
Katarzyna Danys
Keyword(s):  
Olive Oil ◽  
Everyday Life ◽  
North Africa ◽  
Fish Sauce ◽  
North African ◽  
Preliminary Assessment ◽  
Different Types ◽  
Large Vessels

Rescue excavations undertaken in hermitage EE.50 in Naqlun in 2016 brought to light an extensive pottery assemblage composed of red-slipped goblets, bowls and plates of Egyptian origin, made of alluvial fabrics, and a few specimens imported from North African workshops. The repertoire of tableware was complemented with qullae made of marl and alluvial clays. Numerous cooking pots, pans and a single lid represent kitchen equipment. Goods were kept in large vessels of different types. Commodities such as wine, olive oil or fish sauce were delivered in amphorae: Egyptian LRA 7 and imported vessels, originating from North Africa (Tunisia), Cilicia, Cyprus and Rhodes(?). This assemblage has revealed some aspects of everyday life in the hermitage and confirmed the independent self-sufficient lifestyle of its inhabitants. The pottery assemblage is from the middle to the end of the 5th century AD.

scholarly journals Confidence interval for quantiles and percentiles

2018 ◽  
Vol 29 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Cristiano Ialongo
Keyword(s):  
Confidence Interval ◽  
Laboratory Medicine ◽  
Reference Intervals ◽  
Population Parameter ◽  
Statistical Tools ◽  
Underlying Distribution ◽  
Performance Specification ◽  
Performance Specifications ◽  
And Performance ◽  
Sample Estimate

Quantiles and percentiles represent useful statistical tools for describing the distribution of results and deriving reference intervals and performance specification in laboratory medicine. They are commonly intended as the sample estimate of a population parameter and therefore they need to be presented with a confidence interval (CI). In this work we discuss three methods to estimate CI on quantiles and percentiles using parametric, nonparametric and resampling (bootstrap) approaches. The result of our numerical simulations is that parametric methods are always more accurate regardless of sample size when the procedure is appropriate for the distribution of results for both extreme (2.5th and 97.5th) and central (25th, 50th and 75th) percentiles and corresponding quantiles. We also show that both nonparametric and bootstrap methods suit well the CI of central percentiles that are used to derive performance specifications through quality indicators of laboratory processes whose underlying distribution is unknown.

scholarly journals Variability of Vomitoxin in Truckloads of Wheat in a Wheat Scab Epidemic Year

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 625-630 ◽  
Author(s):  
L. P. Hart ◽  
O. Schabenberger
Keyword(s):  
Confidence Interval ◽  
Confidence Intervals ◽  
Gibberella Zeae ◽  
Wheat Scab ◽  
Wheat Products ◽  
Serious Disease ◽  
Ground Wheat ◽  
Precise Assessment ◽  
The U.S ◽  
Sample Estimate

Wheat scab, caused by Gibberella zeae, has been a serious disease in parts of the Midwest. One factor contributing to the importance of wheat scab is the contamination of grain by the mycotoxin vomitoxin (deoxynivalenol, DON), a toxic secondary metabolite. The U.S. Food and Drug Administration advisory levels for vomitoxin in wheat and wheat products require an accurate and precise assessment of vomitoxin concentration. In this study, randomly collecting probes of wheat from individual trucks and analyzing the ground wheat from each probe produced significantly less variability than subsampling and analyzing 50 g of whole kernels from the probes. The variability introduced by subsampling the probes and analyzing 50 g of whole kernels affects the precision and confidence of vomitoxin estimates. Tables of confidence intervals were developed for different sampling and subsampling patterns. To be 95% certain that the true vomitoxin concentration does not exceed the sample estimate by 1 μg/g, analyzing either four individual probes or 5–12% subsamples of these probes would be sufficient. To increase the accuracy to about 0.5 μg/g, either an analysis of seven probes or a 5–12% subsample of 10 probes would be necessary, based on a one-sided confidence interval.

scholarly journals Classification of Tropical Precipitating Systems Using Wind Profiler Spectral Moments. Part II: Statistical Characteristics of Rainfall Systems and Sensitivity Analysis

2008 ◽  
Vol 25 (6) ◽  
pp. 898-908 ◽  
Author(s):  
T. Narayana Rao ◽  
N. V. P. Kirankumar ◽  
B. Radhakrishna ◽  
D. Narayana Rao ◽  
K. Nakamura
Keyword(s):  
Wide Spectrum ◽  
Companion Paper ◽  
Statistical Characteristics ◽  
Wind Profiler ◽  
Convective Systems ◽  
Rain Gauges ◽  
Tropical Precipitation ◽  
Precipitation Regimes ◽  
Different Types ◽  
Rainfall Statistics

Abstract An automated precipitation algorithm to classify tropical precipitating systems has been described in a companion paper (Part I). In this paper, the algorithm has been applied to 18 months of lower atmospheric wind profiler measurements to study the vertical structure and statistical features of different types of tropical precipitating systems over Gadanki, India. The shallow precipitation seems to be an important component of tropical precipitation, because it is prevalent for about 23% of the observations, with a rainfall fraction of 16%. As expected, the deep convective systems contribute maximum (60%) to the total rainfall, followed by transition and stratiform precipitation. Nonprecipitating clouds (clouds associated with no surface rainfall) are predominant in transition category, indicating that evaporation of precipitation is significant in this region. The quantitative rainfall statistics in different precipitation regimes are compared and contrasted between themselves and also with those reported at different geographical locations obtained with a wide spectrum of instruments, from rain gauges to profilers and scanning radars. The results herein agree with the reports based on scanning radar measurements but differ from profiler-based statistics. The discrepancies are discussed in light of differences in classification schemes, variation in geographical conditions, etc. The sensitivity of the algorithm on the choice of thresholds for identifying different types of precipitating systems is also examined.

The Significance of Particle Size in Sand Erosion of Small Gas Turbines

1969 ◽  
Vol 73 (701) ◽  
pp. 427-428 ◽  
Author(s):  
Wendy Sage ◽  
G. P. Tilly
Keyword(s):  
Particle Size ◽  
North Africa ◽  
Gas Turbines ◽  
Laboratory Experiments ◽  
The Other ◽  
Erosion Damage ◽  
Surge Margin ◽  
Sand Erosion ◽  
Different Types ◽  
Engine Life

Operation of vehicles over dusty terrains and unprepared airstrips has highlighted the erosion problems incurred by ingestion of dusty air. Hibbert summarised the experience from British helicopter trials up to that date and drew attention to some of the factors that influenced the extent of erosion damage and to methods of minimising it. He cited a trial during 1963 in which a twin-engine Wessex Mk 2 helicopter having one intake protected by felt filters was tested in North Africa. Some idea of the severity of the problem may be gained from the fact that the unprotected engine surged after 3h 40 min while the other was found to have lost half its surge margin. However, operation can usually be arranged so that time spent in the dusty environment is minimised and service lives under desert conditions may be typically around 100h. In attempts to improve lives to a more acceptable level, different types of filtration have been investigated and the mechanism of erosion studied in some detail. This note describes some laboratory experiments to determine the influence of particle size on the erosion and attempts to relate this to filtration and engine life.

scholarly journals Flavonoids with Glutathione Antioxidant Synergy: Influence of Free Radicals Inflow

Antioxidants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 695 ◽  
Author(s):  
Igor Ilyasov ◽  
Vladimir Beloborodov ◽  
Daniil Antonov ◽  
Anna Dubrovskaya ◽  
Roman Terekhov ◽  
...  
Keyword(s):  
Free Radicals ◽  
Free Radical ◽  
Antioxidant Capacity ◽  
Sulfonic Acid ◽  
Lag Time ◽  
The Other ◽  
Molar Ratio ◽  
Different Types ◽  
Great Excess ◽  
The One

This report explores the antioxidant interaction of combinations of flavonoid–glutathione with different ratios. Two different 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid radical (ABTS•+)-based approaches were applied for the elucidation of the antioxidant capacity of the combinations. Despite using the same radical, the two approaches employ different free radical inflow systems: An instant, great excess of radicals in the end-point decolorization assay, and a steady inflow of radicals in the lag-time assay. As expected, the flavonoid–glutathione pairs showed contrasting results in these two approaches. All the examined combinations showed additive or light subadditive antioxidant capacity effects in the decolorization assay. This effect showed slight dilution dependence and did not change when the initial ABTS•+ concentration was two times as high or low. However, in the lag-time assay, different types of interaction were detected, from subadditivity to considerable synergy. Taxifolin–glutathione combinations demonstrated the greatest synergy, at up to 112%; quercetin and rutin, in combination with glutathione, revealed moderate synergy in the 30–70% range; while morin–glutathione appeared to be additive or subadditive. In general, this study demonstrated that, on the one hand, the effect of flavonoid–glutathione combinations depends both on the flavonoid structure and molar ratio; on the other hand, the manifestation of the synergy of the combination strongly depends on the mode of inflow of the free radicals.

Who Favors al-Qaeda? Anti-Americanism, Religious Outlooks, and Favorable Attitudes toward Terrorist Organizations

2017 ◽  
Vol 70 (3) ◽  
pp. 480-494 ◽  
Author(s):  
Sabri Ciftci ◽  
Becky J. O’Donnell ◽  
Allison Tanner
Keyword(s):  
North Africa ◽  
Significant Variation ◽  
Missing Values ◽  
Negative Impact ◽  
Al Qaeda ◽  
Ordinary People ◽  
American Democracy ◽  
Terrorist Organizations ◽  
Different Types ◽  
Terrorist Groups

This study examines why ordinary people sympathize with a terrorist network in the Middle East and North Africa (MENA). Holding literalist religious outlook resonating with al-Qaeda’s marginal interpretation of Islam constant, it is maintained that anti-Americanism and its varieties matter a great deal in explaining attitudes toward al-Qaeda. Using Pew Global Attitudes Surveys conducted in Turkey, Egypt, Jordan, and Tunisia, the authors run conditional mixed process estimations combining seemingly unrelated regressions with selection models to account for the missing values and endogeneity problems. The analysis reveals significant variation both cross-nationally and in the effects of varieties of anti-Americanism on favorability of al-Qaeda. While the dislike of certain aspects of American culture generates sympathy toward al-Qaeda, anti-Americanism as a general attitude does not. More interestingly, dislike of American democracy, technology, and policy has either negative or no effect on favorable views of al-Qaeda. Literalist religious outlook generates positive views of al-Qaeda, but religiosity has a negative impact. These findings imply that we need to draw careful distinctions between politicized Islamic preferences and personal religiosity as well as the different types of anti-American sentiments in understanding Muslim political attitudes about terrorist groups.

Sign in / Sign up

Export Citation Format

Share Document