Evaluating the replicability of social science experiments in Nature and Science between 2010 and 2015

Being able to replicate scientific findings is crucial for scientific progress. We replicate 21 systematically selected experimental studies in the social sciences published in Nature and Science between 2010 and 2015. The replications follow analysis plans reviewed by the original authors and pre-registered prior to the replications. The replications are high powered, with sample sizes on average about five times higher than in the original studies. We find a significant effect in the same direction as the original study for 13 (62%) studies, and the effect size of the replications is on average about 50% of the original effect size. Replicability varies between 12 (57%) and 14 (67%) studies for complementary replicability indicators. Consistent with these results, the estimated true-positive rate is 67% in a Bayesian analysis. The relative effect size of true positives is estimated to be 71%, suggesting that both false positives and inflated effect sizes of true positives contribute to imperfect reproducibility. Furthermore, we find that peer beliefs of replicability are strongly related to replicability, suggesting that the research community could predict which results would replicate and that failures to replicate were not the result of chance alone

Anti-Osteoporotic Effect of Lactobacillus brevis AR281 in an Ovariectomized Mouse Model Mediated by Inhibition of Osteoclast Differentiation

Osteoporosis is a global disease characterized by weakened bone microarchitecture, leading to osteoporotic fractures. Estrogen replacement therapy is the traditional treatment for osteoporosis but carries with it an increased risk of cardiac events. In search of a safe and effective treatment, we used Lactobacillus brevis AR281, which has anti-inflammatory properties, to conduct a 7-week experiment, investigating its inhibitory effects on osteoporosis in an ovariectomized (ovx) mouse model. The results demonstrated that AR281 significantly improved bone microarchitecture and biomechanical strength in ovx mice by attenuating bone resorption. AR281 significantly decreased the critical osteoclast activator, the ratio of the receptor activator for nuclear factor kappa B (NF-κB) ligand (RANKL) to osteoprotegerin, and pro-inflammatory osteoclastogenic mediators, such as IL-1, IL-6, and IL-17, which can increase the RANKL expression. Moreover, AR281 modulated intestinal microbiota in ovx mice increased the abundance of Akkermansia, which is responsible for the improvement of gut epithelial barrier integrity. In an in vitro trial, AR281 suppressed the number of osteoclasts differentiated from the osteoclast precursor RAW264.7 cells caused by RANKL through the tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6)/NF-κB/nuclear factor of activated T cells c1 (NFATc1) pathway. Therefore, AR281 may be a natural alternative for combating osteoporosis

The Phylogeography of Deciduous Tree <i>Ulmus macrocarpa</i> (Ulmaceae) in Northern China

Disentangling how climate oscillations and geographical events significantly influence plants’ genetic architecture and demographic history is a central topic in phytogeography. The deciduous ancient tree species Ulmus macrocarpa is primarily distributed throughout Northern China and has timber and horticultural value. In the current study, we studied the phylogenic architecture and demographical history of U. macrocarpa using chloroplast DNA with ecological niche modeling. The results indicated that the populations’ genetic differentiation coefficient (NST) value was significantly greater than the haplotype frequency (GST) (p U. macrocarpa had a clear phylogeographical structure. Phylogenetic inference showed that the putative chloroplast haplotypes could be divided into three groups, in which the group Ⅰ was considered to be ancestral. Despite significant genetic differentiation among these groups, gene flow was detected. The common ancestor of all haplotypes was inferred to originate in the middle–late Miocene, followed by the haplotype overwhelming diversification that occurred in the Quaternary. Combined with demography pattern and ecological niche modeling, we speculated that the surrounding areas of Shanxi and Inner Mongolia were potential refugia for U. macrocarpa during the glacial period in Northern China. Our results illuminated the demography pattern of U. macrocarpa and provided clues and references for further population genetics investigations of precious tree species distributed in Northern China

Detection and Categorization of Diarrheagenic Escherichia coli with Auto-microfluidic Thin-film Chip Method

Diarrheagenic Escherichia coli (DEC) causes human diarrhea symptom in both healthy and immunocompromised individuals. An auto-microfluidic thin-film chip (AMTC) instrument integrating one-step multiplex PCR (mPCR) with reverse dot blot hybridization (RDBH) was developed for highthroughput detection of DEC. The novel mPCR method was developed by designing 14 specific primers and corresponding probes. 14 indexes including an endogenous gene (uidA) and 13 pathogenic genes (stx1, stx2, escV, ipaH, invE, estB, lt, pic, aggR, astA, bfpB, sth and stp) of DEC were detected. This one-step mPCR + RDBH approach is useful for simultaneous detection of numerous target genes in a single sample, whose specificity and availability have been confirmed on the positive control of 11 DEC strains. In addition, with 300 diarrheal stool samples being detected by this method, 21 were found to contain five major DEC strains. Compared with monoplex PCR and previous one-step mPCR approach, this method could detect ipaH and estB, and compared with current commercial kit, the relevance ratio of DEC detected by the AMTC method was increased by 1% in stool samples. Furthermore, the novel integration AMTC device could be a valuable detection tool for categorization of E. coli

Qualifying Event and Recurrence of Ischemic Stroke in Symptomatic Artery Occlusion: A Post Hoc Analysis of CMOSS

Background The authors aimed to elucidate the relationship between latest ischemic event and the incidence of subsequent ischemic stroke in patients with symptomatic artery occlusion. Methods and Results We analyzed the association between qualifying event—the latest ischemic event (transient ischemic attack [TIA] or stroke)—and the incidence of ipsilateral ischemic stroke in patients with symptomatic artery occlusion treated with medical therapy alone in CMOSS (Carotid or Middle Cerebral Artery Occlusion Surgery Study). The incidence of CMOSS primary outcomes, including any stroke or death within 30 days after randomization or ipsilateral ischemic stroke between 30 days and 2 years, between the bypass surgical and medical groups, stratified by qualifying events, was also compared. Of the 165 patients treated with medical therapy alone, 75 had a TIA and 90 had a stroke as their qualifying event. The incidence of ipsilateral ischemic stroke did not significantly differ between patients with a TIA and those with a stroke as their qualifying event (13.3% versus 6.7%, P=0.17). In multivariate analysis, the qualifying event was not associated with the incidence of ipsilateral ischemic stroke. There were no significant differences in the CMOSS primary outcomes between the surgical and medical groups, regardless of the qualifying event being TIA (10.1% versus 12.2%, P=0.86) or stroke (6.7% versus 8.9%, P=0.55). Conclusions Among patients with symptomatic artery occlusion and hemodynamic insufficiency, the risk of subsequent ipsilateral ischemic stroke does not appear to be lower in patients presenting with a TIA compared with those with a stroke. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01758614

Complete Repository (*.zip)

All data and scripts to reproduce the aggregate results, figures, and tables reported in the manuscript and the supplementary information as a single *.zip-file

Survey

Pre-market survey for elicitation of peer beliefs about replicabilit