scholarly journals On the statistical significance of communities from weighted graphs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zengyou He ◽  
Wenfang Chen ◽  
Xiaoqi Wei ◽  
Yan Liu
Keyword(s):  
Censored Data ◽  
Statistical Significance ◽  
Significance Testing ◽  
Edge Weight ◽  
Weighted Graphs ◽  
Logrank Test ◽  
Weighted Networks ◽  
Sample Test ◽  
Definition Of ◽  
New Formulation

AbstractCommunity detection is a fundamental procedure in the analysis of network data. Despite decades of research, there is still no consensus on the definition of a community. To analytically test the realness of a candidate community in weighted networks, we present a general formulation from a significance testing perspective. In this new formulation, the edge-weight is modeled as a censored observation due to the noisy characteristics of real networks. In particular, the edge-weights of missing links are incorporated as well, which are specified to be zeros based on the assumption that they are truncated or unobserved. Thereafter, the community significance assessment issue is formulated as a two-sample test problem on censored data. More precisely, the Logrank test is employed to conduct the significance testing on two sets of augmented edge-weights: internal weight set and external weight set. The presented approach is evaluated on both weighted networks and un-weighted networks. The experimental results show that our method can outperform prior widely used evaluation metrics on the task of individual community validation.

scholarly journals EXPRESS: Efficacy and Safety of Tadalafil in a Pediatric Population with Pulmonary Arterial Hypertension: Phase 3 randomized, Double Blind Placebo-Controlled Study

2021 ◽  
pp. 204589402110249
Author(s):  
David D Ivy ◽  
Damien Bonnet ◽  
Rolf MF Berger ◽  
Gisela Meyer ◽  
Simin Baygani ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Statistical Significance ◽  
Significance Testing ◽  
Efficacy And Safety ◽  
Phase 3 ◽  
Statistical Significance Testing ◽  
Double Blind ◽  
Double Blind Placebo ◽  
Treatment Groups ◽  
Pulmonary Arterial

Objective: This study evaluated the efficacy and safety of tadalafil in pediatric patients with pulmonary arterial hypertension (PAH). Methods: This phase-3, international, randomized, multicenter (24 weeks double-blind placebo controlled period; 2-year, open-labelled extension period), add-on (patient’s current endothelin receptor antagonist therapy) study included pediatric patients aged <18 years with PAH. Patients received tadalafil 20 mg or 40 mg based on their weight (Heavy-weight: ≥40 kg; Middle-weight: ≥25—<40 kg) or placebo orally QD for 24 weeks. Primary endpoint was change from baseline in 6-minute walk (6MW) distance in patients aged ≥6 years at Week 24. Sample size was amended from 134 to ≥34 patients, due to serious recruitment challenges. Therefore, statistical significance testing was not performed between treatment groups. Results: Patient demographics and baseline characteristics (N=35; tadalafil=17; placebo=18) were comparable between treatment groups; median age was 14.2 years (6.2 to 17.9 years) and majority (71.4%, n=25) of patients were in HW cohort. Least square mean (SE) changes from baseline in 6MW distance at Week 24 was numerically greater with tadalafil versus placebo (60.48 [20.41] vs 36.60 [20.78] meters; placebo-adjusted mean difference [SD] 23.88 [29.11]). Safety of tadalafil treatment was as expected without any new safety concerns. During study period 1, two patients (1 in each group) discontinued due to investigator’s reported clinical worsening, and no deaths were reported. Conclusions: The statistical significance testing was not performed between the treatment groups due to low sample size, however, the study results show positive trend in improvement in non invasive measurements, commonly utilized by clinicians to evaluate the disease status for children with PAH. Safety of tadalafil treatment was as expected without any new safety signals.

scholarly journals Large-Eddy Simulation Analyses of Heated Urban Canyon Facades

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3078
Author(s):  
Carlo Cintolesi ◽  
Francesco Barbano ◽  
Silvana Di Sabatino
Keyword(s):  
Urban Canopy ◽  
Pollutant Removal ◽  
Present Contribution ◽  
Convective Flows ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Isothermal Case ◽  
Definition Of ◽  
New Formulation ◽  
Heating Up

Thermal convective flows are common phenomena in real urban canyons and strongly affect the mechanisms of pollutant removal from the canyon. The present contribution aims at investigating the complex interaction between inertial and thermal forces within the canyon, including the impacts on turbulent features and pollutant removal mechanisms. Large-eddy simulations reproduce infinitely long square canyons having isothermal and differently heated facades. A scalar source on the street mimics the pollutant released by traffic. The presence of heated facades triggers convective flows which generate an interaction region around the canyon-ambient interface, characterised by highly energetic turbulent fluxes and an increase of momentum and mass exchange. The presence of this region of high mixing facilitates the pollutant removal across the interface and decreases the urban canopy drag. The heating-up of upwind facade determines favourable convection that strengthens the primary internal vortex and decreases the pollutant concentration of the whole canyon by 49% compare to the isothermal case. The heating-up of the downwind facade produces adverse convection counteracting the wind-induced motion. Consequently, the primary vortex is less energetic and confined in the upper-canyon area, while a region of almost zero velocity and high pollution concentration (40% more than the isothermal case) appears at the pedestrian level. Finally, numerical analyses allow a definition of a local Richardson number based on in-canyon quantities only and a new formulation is proposed to characterise the thermo-dynamics regimes.

The Numbers Will Love You Back in Return—I Promise

2016 ◽  
Vol 11 (4) ◽  
pp. 551-554 ◽  
Author(s):  
Martin Buchheit
Keyword(s):  
Sample Size ◽  
Null Hypothesis ◽  
Clinical Medicine ◽  
Statistical Significance ◽  
Significance Testing ◽  
Null Hypothesis Significance Testing ◽  
Sport Science ◽  
Size Dependent ◽  
Research Questions ◽  
Per Se

The first sport-science-oriented and comprehensive paper on magnitude-based inferences (MBI) was published 10 y ago in the first issue of this journal. While debate continues, MBI is today well established in sport science and in other fields, particularly clinical medicine, where practical/clinical significance often takes priority over statistical significance. In this commentary, some reasons why both academics and sport scientists should abandon null-hypothesis significance testing and embrace MBI are reviewed. Apparent limitations and future areas of research are also discussed. The following arguments are presented: P values and, in turn, study conclusions are sample-size dependent, irrespective of the size of the effect; significance does not inform on magnitude of effects, yet magnitude is what matters the most; MBI allows authors to be honest with their sample size and better acknowledge trivial effects; the examination of magnitudes per se helps provide better research questions; MBI can be applied to assess changes in individuals; MBI improves data visualization; and MBI is supported by spreadsheets freely available on the Internet. Finally, recommendations to define the smallest important effect and improve the presentation of standardized effects are presented.

Recurrent Instability after Arthroscopic Glenoid Labral Repair with a Minimum of Three Points of Fixation: Do the Number of Anchors or Fixation Points Correlate to Outcomes?

2021 ◽  
Author(s):  
Sean Mc Millan ◽  
Brian Fliegel ◽  
Michael Stark ◽  
Elizabeth Ford ◽  
Manuel Pontes ◽  
...  
Keyword(s):  
Shoulder Instability ◽  
Statistical Significance ◽  
Labral Repair ◽  
Secondary Outcome ◽  
Consecutive Series ◽  
Recurrent Instability ◽  
Significant Difference ◽  
Fixation Points ◽  
Definition Of ◽  
Shoulder Score

Introduction: The goal of this study was to evaluate the recurrence rate of instability following arthroscopic Bankart repairs in regard to the number and types of fixation utilized. A Bankart lesion is a tear in the anteroinferior capsulolabral complex within the shoulder, occurring in association with an anterior shoulder dislocation. These injuries can result in glenoid bone loss, decreased range of motion, and recurrent shoulder instability. Successful repair of these lesions has been reported in the literature with repair constructs that have three points of fixation. However, the definition of “one point of fixation” is yet to be fully elucidated. Materials and Methods: A consecutive series of arthroscopically repaired Bankart lesions were evaluated pertaining to the points of fixation required to achieve shoulder stability. This included the number, position, and types of anchors used. Patients consented to complete a series of surveys at a minimum of two years postoperatively. The primary outcome was to determine recurrent instability via the UCLA Shoulder Score, the ROWE Shoulder Instability Score, and the Oxford Shoulder Score. A secondary outcome included pain on a Visual Analog Scale (VAS). Results: There were 116 patients reviewed, 46 patients achieved three points of fixation in their surgical repair via two anchors and 70 patients achieved a similar fixation with three or more anchors. There was no significant difference in the mean age, gender, or body mass index (BMI). Patients receiving two anchors demonstrated recurrent instability 8.7% of the time (4 of 46 patients). Patients who received three or more anchors demonstrated recurrent instability 8.6% of the time (6 of 70 patients). Overall, there was no statistical significance between the number/types of anchors used. Between the two cohorts, there was no statistically significant difference found between VAS, ROWE, UCLA, and Oxford Scores. There was a significant difference in pain reported on the VAS scale with an average VAS score of 0.43 versus 2.5 in those without and with recurrent instability respectively. Conclusion: Contention still exists surrounding the exact definition of “a point of fixation” in arthroscopic Bankart repairs. Three-point constructs can be created through a variety of combinations including anchors and sutures, ultimately achieving the goal of a stable shoulder.

scholarly journals Is Banning Significance Testing the Best Way to Improve Applied Social Science Research? – Questions on

2016 ◽  
Vol 21 (3) ◽  
pp. 95-105
Author(s):  
Thees F Spreckelsen ◽  
Mariska Van Der Horst
Keyword(s):  
Social Science ◽  
Statistical Significance ◽  
Social Science Research ◽  
Science Research ◽  
Research Process ◽  
Significance Testing ◽  
Sociological Research ◽  
Research Practice ◽  
Research Questions ◽  
Applied Social Science

Significance testing is widely used in social science research. It has long been criticised on statistical grounds and problems in the research practice. This paper is an applied researchers’ response to Gorard's (2016) ‘Damaging real lives through obstinacy: re-emphasising why significance testing is wrong’ in Sociological Research Online 21(1). He participates in this debate concluding from the issues raised that the use and teaching of significance testing should cease immediately. In that, he goes beyond a mere ban of significance testing, but claims that researchers still doing this are being unethical. We argue that his attack on applied scientists is unlikely to improve social science research and we believe he does not sufficiently prove his claims. In particular we are concerned that with a narrow focus on statistical significance, Gorard misses alternative, if not more important, explanations for the often-lamented problems in social science research. Instead, we argue that it is important to take into account the full research process, not just the step of data analysis, to get a better idea of the best evidence regarding a hypothesis.

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