Defining clusters of related industries Delgado, Mercedes; Porter, Michael E.; Stern, Scott
Journal of economic geography,
01/2016, Letnik:
16, Številka:
1
Journal Article
Recenzirano
Clusters are geographic concentrations of industries related by knowledge, skills, inputs, demand and/or other linkages. There is an increasing need for cluster-based data to support research, ...facilitate comparisons of clusters across regions and support policymakers in defining regional strategies. This article develops a novel clustering algorithm that systematically generates and assesses sets of cluster definitions (i.e., groups of closely related industries). We implement the algorithm using 2009 data for U.S. industries (six-digit NAICS), and propose a new set of benchmark cluster definitions that incorporates measures of inter-industry linkages based on co-location patterns, input–output links, and similarities in labor occupations. We also illustrate the algorithm’s ability to compare alternative sets of cluster definitions by evaluating our new set against existing sets in the literature. We find that our proposed set outperforms other methods in capturing a wide range of inter-industry linkages, including the grouping of industries within the same three-digit NAICS.
Chilinia is an extinct genus of cycads, established by Li and Ye in 1964 based on leaf fossils from the Lower Cretaceous in Jilin Province, China. Morphologically, the genus Chilinia closely ...resembles Ctenis, another cycad foliage genus, in having pinnately divided leaves with laterally inserted pinnae on the rachis and reticulate venation but differs mainly from the latter in having toothed or irregularly lobed rather than entire-margined pinnae. Fossil records show that up to now, nine species of Chilinia have been reported worldwide, representing an index fossil plant in the Jurassic to Early Cretaceous. In this study, we present a comprehensive overview of all reported Chilinia fossils from a systematic palaeobotanical perspective. Fossil records indicate that Chilinia mainly occurred in the middle–high latitudes of the northern and southern hemispheres in Pangea from the Middle Jurassic to Middle Cretaceous. Combined evidence from the morphology of Chilinia and its floral patterns suggests that the genus probably lived in humid warm-temperate palaeoclimatic conditions with brief seasonal variations.
•A comprehensive overview of the extinct cycad Chilinia fossils are performed by morphological and cluster analysis approaches.•Chilinia has 9 species worldwide, represents an index plant taxon during Middle Jurassic to Middle Cretaceous.•Global fossil records show that Chilinia distributed in middle to high latitude of both northern and southern hemispheres in Pangea.•Chilinia lived in humid warm-temperate paleoclimate condition with seasonal variations.
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.
Sharing economy: a co-citation analysis Sainaghi, Ruggero; Köseoglu, Mehmet Ali; d'Angella, Francesca ...
Current issues in tourism,
04/2020, Letnik:
23, Številka:
8
Journal Article
Recenzirano
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.
The daily cycle of pollen concentrations reflects its genetic response to environmental conditions. The detailed study of these cycles was used to identify the influence of external sources on local ...pollen levels. In this work, three different daily profiles (Ci) of Olea pollen concentrations were identified in the city of Alicante (southeastern Spain) using cluster analysis. For this, 2-h data from 2010 to 2015 were used. The percentage frequency, pollen index and mean Olea pollen concentration (in pollen grains∙m−3) for each cluster were: C1 (∼91%, 8797, 26), C2 (∼7%, 4641,179) and C3 (∼2%, 1845, 308). C1 was the predominant pattern throughout the whole MPS, while C2 and C3 were only present in the middle of the MPS. Small variations in pollen concentrations throughout the day were observed for C1, while C2 and C3 showed the highest pollen concentration at ∼04:00 UTC and 10:00 UTC, respectively. C1 represented concentration patterns due to local pollen inputs, being influenced by precipitation events, sea breezes and the recirculation of air pollutants. On the other hand, C2 and C3 were strongly influenced by external pollen inputs from southwestern regions of Spain. The results of this study indicate that external inputs from these regions were associated with exposure of the population to high pollen concentrations for short periods of time. In contrast, inputs from the northwest were associated with exposure to lower pollen concentrations for longer periods of time.
•Medium-range Olea pollen transport mask the influence of atmospheric events characteristic of the Mediterranean area.•Medium-range Olea pollen transport was observed before sunrise and in the afternoon.•“Hourly Olea pollen exposure" levels were estimated for the first time.
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
The planning of training factors is determinant for the effectiveness of training process, but also to maximize the technical staff ability. However, the research about training factors planning is ...scarcely explored. The aims of this study were to identify different types of training sessions according to training factors predominance intended and compare the player's perceptual response and live time sessions, according to training sessions typology. According to the clustering procedures, the training sessions were grouped into three training factors dominance categories, such as tactical, technical, and multifactorial. The between-cluster analysis revealed slightly higher perceptual response in multifactorial training sessions. However, small-to-moderate differences were observed for technical dominance training sessions compared to other types of sessions. The present findings showed that the training sessions could be classified according to coach's intentionality. and player's perceptual response and live time is associated with training objectives.
„Fachbegriff“ und „Grundbegriff“ sind spärlich definiert, spielen aber im Lern‐ und Prüfgeschehen eine bedeutende Rolle. Schulbüchern kommt diesbezüglich eine Vorbildfunktion zu. In einer ...Schulbuchreihe für Jgst. 8–10 wurden zunächst quantitativ Fachbegriffe gezählt und in Kategorien eingeteilt. Dies ergab nach Bereinigung von Mehrfachnennungen über 7700 Fachbegriffe. Danach wurde auf Grund einer Two‐Step‐Clusteranalyse nach Häufigkeit der Nennung und Vernetzung sowie nach Experten‐Rating ein Minimum von 108 Grundbegriffen formuliert, ohne die der Chemieunterricht nicht auskommt. Durch Vergleich dreier Schulbücher und den Einbezug von 9 Experten‐Rankings konnte gezeigt werden, dass das Ausweisen von Grundbegriffen in hohem Maß ein subjektiver Prozess ist. Deswegen wären normative Bemühungen aller Instanzen des Chemieunterrichts sehr sinnvoll.
The main goal of this thesis is to determine the most important effective factors for student admission and his/her interests in the specialization by using multivariate methods. Therefore, it ...focused on using factor analysis by identifying a number of the obtained factors and cluster analysis by classifying them into five clusters. Furthermore, the factor analysis and cluster analysis results will be compared to each other. Moreover, this study depends on the analysis of 350 questionnaire forms, distributed by random stratified sample method on students in the first stage of three different colleges, including Scientific colleges and Humanity colleges of Salahaddin University in Northern Iraq for the academic year 2018-2019. Thus, the IBM SPSS Statistics V: 25 software programs have been used in data analysis. Additionally, the results have demonstrated that Reliability is accepted, and also in factor analysis, the rate of the total variance interpretation is %62.157. Moreover, the most common variables between the factor analysis and cluster analysis can be considered the most important and influential variables for student admission and their interests in choosing a specialization. Consequently, the first factor and the first cluster have five significant variables in common; they are V1, V2, V3, V4 and V5 (the system is helpful for student admission to colleges to get their desired professions). The second factor and the second cluster have four influential variables in common they are V24, V32, V35 and V37 (the new system may help master's and PhD students to be admitted to colleges and get competitive results by utilizing their accounts). In the fourth factor and the fourth cluster, there is one variable in common, which is V18 (decreasing the number of students admitted in the parallel system by using the graduated students who must not be able to refill admission forms). Ultimately, the conclusion has shown a kind of approach and similarity between factor analysis and cluster analysis.
PDF
