Sharing economy: a co-citation analysis Sainaghi, Ruggero; Köseoglu, Mehmet Ali; d'Angella, Francesca ...
Current issues in tourism,
04/2020, Volume:
23, Issue:
8
Journal Article
Peer reviewed
This study aims to investigate the intellectual structure of P2P accommodation platforms through a co-citation analysis by using a social network approach. To this end, this paper analyzed 79 ...articles retrieved from the Scopus database. The findings show that there is a clear connection between the intellectual structures of P2P platforms and tourism journals. The cluster analysis identifies four groups, representing the intellectual structure of the P2P platforms. We discuss three relevant topics related to the theoretical pillars: the different levels of analysis, the diverse disciplines involved, and the increasing centrality gain by hospitality and tourism (H&T) studies. For each point, a future research agenda is proposed.
Two robustness criteria are presented that are applicable to general clustering methods. Robustness and stability in cluster analysis are not only data dependent, but even cluster dependent. ...Robustness is in the present paper defined as a property of not only the clustering method, but also of every individual cluster in a data set. The main principles are: (a) dissimilarity measurement of an original cluster with the most similar cluster in the induced clustering obtained by adding data points, (b) the dissolution point, which is an adaptation of the breakdown point concept to single clusters, (c) isolation robustness: given a clustering method, is it possible to join, by addition of
g points, arbitrarily well separated clusters?
Results are derived for
k-means,
k-medoids (
k estimated by average silhouette width), trimmed
k-means, mixture models (with and without noise component, with and without estimation of the number of clusters by BIC), single and complete linkage.
Primary cultures of human corneal endothelial cells (HCECs) are an important model system for studying the pathophysiology of corneal endothelium. The purpose of this study was to identify and ...validate an optimal primary culture model of normal and Fuchs endothelial corneal dystrophy (FECD) endothelial cells by comparing cell morphology and marker expression under different media conditions to in vivo donor tissues. Primary and immortalized HCECs, isolated from normal and FECD donors, were cultured in proliferation media (Joyce, M4, Bartakova) alone or sequentially with maturation media (F99, Stabilization 1, M5). CD56, CD73 and CD166 expressions were quantified in confluent and matured cell lines by flow cytometry. HCECs that were allowed to proliferate in Joyce's medium followed by maturation in low-mitogen containing media yielded cells with similar morphology to corneal endothelial tissues. Elevated expression of CD56 and CD166 and low expression of CD73 correlated with regular, hexagonal-like HCEC morphology. CD56:CD73 > 2.5 was most consistent with normal HCEC morphology and mimicked corneal endothelial tissue. Immortalization of normal HCECs by hTERT transduction showed morphology and CD56:CD73 ratios similar to parental cell lines. HCECs established from FECD donors showed reduced CD56:CD73 ratios compared to normal HCECs which coincided with reduced uniformity and regularity of cell monolayers. Overall, a dual media system with Joyce's medium for proliferation and a low-mitogen media for maturation, provided normal cultures with regular, hexagonal-like cell morphologies consistent with corneal endothelial cells in vivo. CD56:CD73 expression ratio >2.5 was predictive of in vivo-like cellular morphology.
El Niño exerts widespread hydroclimate impacts during boreal summer. However, the current prediction of El Niño across boreal spring has the most severe forecast errors, partially due to the lack of ...understanding diversified El Niño onset and decay. Here we show, through nonlinear k‐means cluster analysis of evolutions of 40 El Niño events since 1870, El Niño exhibits complex and diverse flavors in its onset and decay across boreal spring predictability barrier. We detected three types of El Niño onset and three types of decay. Each type exhibits distinct coupled dynamics, precursors, and hydroclimate impacts. The results guide the prediction of different types of El Niño transition amid spring predictability barrier and global land precipitation during early and late boreal summer. The new classification offers a metric to evaluate performances of climate models and to project future change of El Niño properties and its predictability.
Plain Language Summary
El Niño exerts the most significant climate impacts on human life during boreal summer. However, the prediction of El Niño across boreal spring is most difficult, which is partially due to the lack of understanding of the diversity of El Niño onset and decay. Here we analyzed 40 El Niño events since 1870 and found that El Niño exhibits more complex and diverse flavors in its onset and decay phases than in the mature phase as in conventional analysis. We objectively detected three types of El Niño onset and three types of decay. Each type exhibits distinct physical mechanisms, precursors, and climate impacts. Our results provide clues to predict El Niño transition across spring and offer a metric to evaluate climate models' performance and to project future change of El Niño.
Key Points
El Niño exhibits complex diversity in its onset and decay phases across the boreal spring predictability barrier
Different types of onset/decay processes exhibit distinctive precursors that can foresee different types of El Niño transition in April
Different types of onset/decay show distinct impacts on global land precipitation during early and late boreal summer
We examined the productivity effects of a generative artificial intelligence (AI) technology, the assistive chatbot ChatGPT, in the context of midlevel professional writing tasks. In a preregistered ...online experiment, we assigned occupation-specific, incentivized writing tasks to 453 college-educated professionals and randomly exposed half of them to ChatGPT. Our results show that ChatGPT substantially raised productivity: The average time taken decreased by 40% and output quality rose by 18%. Inequality between workers decreased, and concern and excitement about AI temporarily rose. Workers exposed to ChatGPT during the experiment were 2 times as likely to report using it in their real job 2 weeks after the experiment and 1.6 times as likely 2 months after the experiment.
Recent genomic analyses of pathologically defined tumor types identify “within-a-tissue” disease subtypes. However, the extent to which genomic signatures are shared across tissues is still unclear. ...We performed an integrative analysis using five genome-wide platforms and one proteomic platform on 3,527 specimens from 12 cancer types, revealing a unified classification into 11 major subtypes. Five subtypes were nearly identical to their tissue-of-origin counterparts, but several distinct cancer types were found to converge into common subtypes. Lung squamous, head and neck, and a subset of bladder cancers coalesced into one subtype typified by TP53 alterations, TP63 amplifications, and high expression of immune and proliferation pathway genes. Of note, bladder cancers split into three pan-cancer subtypes. The multiplatform classification, while correlated with tissue-of-origin, provides independent information for predicting clinical outcomes. All data sets are available for data-mining from a unified resource to support further biological discoveries and insights into novel therapeutic strategies.
Display omitted
•New integrated cross-tumor-type classification carries prognostic information•Convergence of a multitissue squamous type•Divergence of bladder cancers into multiple pan-cancer subtypes•Rich resource for data-mining and biological discovery
Integrated genomic and computational analysis across data from 12 tumor types reveals that differences between tumors largely track with tissue of origin, but that molecular data integration provides new prognostic information. Integrated clustering reveals 11 major subtypes that reclassify 10% of tumors and indicates pathway activity differences among tumors with common genomic lesions.
Identifying differentially abundant microbes is a common goal of microbiome studies. Multiple methods are used interchangeably for this purpose in the literature. Yet, there are few large-scale ...studies systematically exploring the appropriateness of using these tools interchangeably, and the scale and significance of the differences between them. Here, we compare the performance of 14 differential abundance testing methods on 38 16S rRNA gene datasets with two sample groups. We test for differences in amplicon sequence variants and operational taxonomic units (ASVs) between these groups. Our findings confirm that these tools identified drastically different numbers and sets of significant ASVs, and that results depend on data pre-processing. For many tools the number of features identified correlate with aspects of the data, such as sample size, sequencing depth, and effect size of community differences. ALDEx2 and ANCOM-II produce the most consistent results across studies and agree best with the intersect of results from different approaches. Nevertheless, we recommend that researchers should use a consensus approach based on multiple differential abundance methods to help ensure robust biological interpretations.
PDF
