scholarly journals Foliar endophytes in trees varying greatly in age

2021 ◽  
Author(s):  
Zhongdong Yu ◽  
Hongru Ding ◽  
Kuocheng Shen ◽  
Fangfang Bu ◽  
George Newcombe ◽  
...  
Keyword(s):  
Exploratory Study ◽  
Leaf Age ◽  
Mechanistic Explanation ◽  
Tree Age ◽  
Botryosphaeria Dothidea ◽  
Platycladus Orientalis ◽  
Age Diversity ◽  
Components Analysis ◽  
Endophyte Community ◽  
Latent Pathogens

AbstractTemple trees, including the gymnosperm Platycladus orientalis and the angiosperm Styphnolobium japonicum, have been planted in China for thousands of years. Tree age thus varies widely from young to ancient trees. Foliar endophytes of P. orientalis and S. japonicum were surveyed in this exploratory study that was based on isolation into culture and sequencing of fungi from trees varying in age from 10 to 5000 years (P. orientalis) and from 10 to 1700 years (S. japonicum). Sequenced endophytes of P. orientalis and S. japonicum belonged to 24 and 16 fungal genera, respectively. Principal components analysis showed that 14 components were necessary to explain 90% of the variance in endophyte community structure in P. orientalis. In S. japonicum eight components were needed for 90%. It is against that backdrop of complex etiology in community structuring, that the relative frequencies (abundances) of 17 of the 24 endophytes from P. orientalis and 9 of the 16 from S. japonicum were significantly correlated with tree age. There were two major trends. Abundant fungal genera [Fusarium + Alternaria = 74.57% (P. orientalis) and 81.24% (S. japonicum)] tended to decline linearly with tree age. Most of the rare fungal genera, in contrast, increased in relative abundance linearly with tree age. Diversity (H′) and richness (Margalef) of endophyte communities in foliage thus increased as the trees aged. Relative abundances of pathogenic endophytes, or latent pathogens, (Pestalotiopsis funerea and Amyloporia subxantha in P. orientalis; Collectotrichum gloeosporioides and Botryosphaeria dothidea in S. japonicum) also increased linearly as the trees aged.Since leaf age does not vary with tree age in the deciduous S. japonicum, nor in the evergreen P. orientalis, ‘tree age’ currently lacks a mechanistic explanation for its apparent importance among common foliar endophytes.

Personality Trait Absorption: An Exploratory Study of Opportunity and Capacity in Relation to Cannabis Use

1995 ◽  
Vol 15 (1) ◽  
pp. 75-101
Author(s):  
Peter L. Nelson
Keyword(s):  
Principal Components Analysis ◽  
Principal Components ◽  
Personality Trait ◽  
Exploratory Study ◽  
Cannabis Use ◽  
Components Analysis ◽  
Relationship Of ◽  
The Relationship ◽  
Tellegen Absorption Scale ◽  
Motivation Loss

Although the Tellegen Absorption Scale has been widely employed in recent years as a measure of personality Trait Absorption, it is argued that this simple score does not sufficiently discriminate true capacity for Absorption nor does it reveal the level of opportunity made for absorptive experiencing. This study operationalizes Capacity and Opportunity as two additional subscales appended to the Tellegen scale and, by employing the technique of Principal Components Analysis, five useful sub-dimensions are generated. Following on from this Author's earlier suggestion that personality Trait Absorption may be linked to cannabis use and depression, an exploratory study was conducted into the relationship of cannabis use, gender, self-perceived motivation loss and depression to observed levels of overall Absorption as well as to levels of Capacity and Opportunity for absorptive experiencing.

scholarly journals Tree age did not affect the leaf anatomical structure or ultrastructure of Platycladus orientalis L. (Cupressaceae)

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7938
Author(s):  
Qianyi Zhou ◽  
Zhaohong Jiang ◽  
Xin Zhang ◽  
Qing Lai ◽  
Yiming Li ◽  
...  
Keyword(s):  
Healthy Aging ◽  
Morphological Structure ◽  
Structural Response ◽  
Research Area ◽  
Anatomical Structure ◽  
Shaanxi Province ◽  
Tree Age ◽  
Platycladus Orientalis ◽  
Sensitive Organ ◽  
Structure And Ultrastructure

Tree aging is a new research area and has attracted research interest in recent years. Trees show extraordinary longevity; Platycladus orientalis L. (Cupressaceae) has a lifespan of thousands of years. Ancient trees are precious historical heritage and scientific research materials. However, tree aging and tree senescence have different definitions and are poorly understood. Since leaves are the most sensitive organ of a tree, we studied the structural response of leaves to tree age. Experiments investigating the leaf morphological structure, anatomical structure and ultrastructure were conducted in healthy P. orientalis at three different ages (ancient trees >2,000 years, 200 years < middle-aged trees <500 years, young trees <50 years) at the world’s largest planted pure forest in the Mausoleum of the Yellow Emperor, Shaanxi Province, China. Interestingly, tree age did not significantly impact leaf cellular structure. Ancient P. orientalis trees in forests older than 2,000 years still have very strong vitality, and their leaves still maintained a perfect anatomical structure and ultrastructure. Our observations provide new evidence for the unique pattern of tree aging, especially healthy aging. Understanding the relationships between leaf structure and tree age will enhance the understanding of tree aging.

An analysis of factors that influence the decision to export: perspective of Brazilian companies

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mara Mataveli ◽  
Juan Carlos Ayala ◽  
Alfonso J. Gil
Keyword(s):  
Principal Component Analysis ◽  
Exploratory Study ◽  
Design Methodology ◽  
Principal Component ◽  
Descriptive Study ◽  
Content Type ◽  
Exporting Firms ◽  
Development Factor ◽  
Components Analysis ◽  
And Performance

PurposeThe objective of this work is to examine the factors that influence the decision of Brazilian companies to export.Design/methodology/approachA questionnaire was used to collect data from a statistically significant sample of 318 Brazilian exporting firms. Three types of study were carried out; an exploratory study that simplified the information through a principal component analysis, a descriptive study of the factors that influence the decision to export by Brazilian companies and a study of variance that allowed comparison of groups of firms.FindingsAfter an analysis of the literature, 11 factors were proposed that influence the decision to export. Two unique factors resulted from the principal components analysis: “resource optimisation” and “performance and development”. The “performance and development” factor was more valued than the “resource optimisation” factor. From the analysis of variance, significant differences were only found in the variable “firm size”.Originality/valueThis paper contributes to the literature by presenting further knowledge of export factors in developing countries, the management of companies and instruments for decision making in the area of internationalisation.

Independent Component Analysis and Immunization: An Exploratory Study

2003 ◽  
Vol 06 (07) ◽  
pp. 721-738 ◽  
Author(s):  
Fabio Bellini ◽  
Ernesto Salinelli
Keyword(s):  
Independent Component Analysis ◽  
Principal Components ◽  
Exploratory Study ◽  
Component Analysis ◽  
Point Of View ◽  
Independent Component ◽  
Theoretical Point ◽  
Immunization Strategies ◽  
Components Analysis ◽  
Empirical Point

In this work we apply Independent Component Analysis (ICA) to the identification of the factors driving spot rates curve movements. A comparison between the standard Principal Components Analysis (PCA) approach and ICA is carried out both from a theoretical point of view, critically analyzing the negentropy based approach to ICA, and from an empirical point of view, where the performance of immunization strategies based on PCA and ICA are tested.

scholarly journals Leaf Age Compared to Tree Age Plays a Dominant Role in Leaf δ13C and δ15N of Qinghai Spruce (Picea crassifolia Kom.)

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 310 ◽  
Author(s):  
Li ◽  
Wang ◽  
Chen ◽  
Xu ◽  
Wu ◽  
...  
Keyword(s):  
Dominant Role ◽  
Leaf Age ◽  
Tree Age ◽  
Relative Importance ◽  
Ecological Stability ◽  
Δ13c And Δ15n ◽  
Picea Crassifolia ◽  
Significant Difference ◽  
Importance Analysis ◽  
Qinghai Spruce

Leaf stable isotope compositions (δ13C and δ15N) are influenced by various abiotic and biotic factors. Qinghai spruce (Picea crassifolia Kom.) as one of the dominant tree species in Qilian Mountains plays a key role in the ecological stability of arid region in the northwest of China. However, our knowledge of the relative importance of multiple factors on leaf δ13C and δ15N remains incomplete. In this work, we investigated the relationships of δ13C and δ15N to leaf age, tree age and leaf nutrients to examine the patterns and controls of leaf δ13C and δ15N variation of Picea crassifolia. Results showed that 13C and 15N of current-year leaves were more enriched than older ones at each tree age level. There was no significant difference in leaf δ13C values among trees of different ages, while juvenile trees (<50 years old) were 15N depleted compared to middle-aged trees (50–100 years old) at each leaf age level except for 1-year-old leaves. Meanwhile, relative importance analysis has demonstrated that leaf age was one of the most important indicators for leaf δ13C and δ15N. Moreover, leaf N concentrations played a dominant role in the variations of δ13C and δ15N. Above all, these results provide valuable information on the eco-physiological responses of P. crassifolia in arid and semi-arid regions.

scholarly journals An Exploratory Study of Emotional Affordance of a Massive Open Online Course

2014 ◽  
Vol 17 (1) ◽  
pp. 43-55 ◽  
Author(s):  
Jeremy C.Y. Cheng
Keyword(s):  
Collaborative Learning ◽  
Computer Science ◽  
Learning Community ◽  
Exploratory Study ◽  
Online Course ◽  
Massive Open Online ◽  
Achievement Emotions ◽  
Virtual Ethnography ◽  
Massive Open Online Course ◽  
Age Diversity

Abstract This exploratory study examines emotional affordance of a massive open online course (MOOC). Postings in a discussion forum of a MOOC in computer science are analysed following a research design informed by virtual ethnography. Emotional affordance is investigated, focusing on nonachievement emotions which are not directly linked to achievement activities or outcomes. The study identifies two non-achievement emotions in the MOOC. First, altruistic emotion evolves with the collaborative learning community and possibly compensates for teachers’ minimal emotional intervention in a large, diverse class. Second, intergenerational emotional resonance is observed and this bears a key implication on managing age diversity for the future MOOCs.

scholarly journals Conveying Positive Regard in Distance Courses: An Exploratory Study

2021 ◽  
Vol 18 (3) ◽  
Author(s):  
Joseph Harder ◽  
◽  
Ayman Abuhamdieh ◽  
Peter Weber ◽  
Keyword(s):  
Learning Outcomes ◽  
Principal Components ◽  
Exploratory Study ◽  
Student Learning Outcomes ◽  
Effect Measure ◽  
Components Analysis ◽  
Distance Delivery ◽  
Distance Courses ◽  
Practical Measure

The present study operationalizes perceived positive regard in the form of a practical measure that can be applied in distance delivery settings. We collected data by surveying distance students at our university. The questions pertained to the quality of learning and the positive regard of the instructor as perceived by the students. Analytical methods included principal components analysis (PCA) to confirm that each group of questions was measuring a common construct, and correlation (Pearson’s r) of the constructs. We found that the effect measure was valid and that it was positively correlated with student learning outcomes.

Dimensions of Peak Communication Experiences: An Exploratory Study

1985 ◽  
Vol 57 (3) ◽  
pp. 824-826 ◽  
Author(s):  
Ronald D. Gordon
Keyword(s):  
Principal Components Analysis ◽  
Principal Components ◽  
Exploratory Study ◽  
Total Variance ◽  
Varimax Rotation ◽  
Peak Experience ◽  
Components Analysis

A brief inventory of characteristics of “peak communication experiences” was developed from Maslow's model of the generalized peak experience. Data from 74 subjects were submitted to principal components analysis with varimax rotation, yielding six factors which accounted for 66.1% of the total variance, as follows: Loving Acceptance (25.9%), Openminded Insight (10.2%), Spontaneity (9.2%), Pleasant Fear (80%), Absorption (7.0%), and Self-detachment (5 8%). Analyses of variance showed that women rated their peak communication experiences higher than men on Loving Acceptance and Spontaneity.

Cluster analysis for large data sets: applications to individual aerosol particles from the mid-pacific

1992 ◽  
Vol 50 (2) ◽  
pp. 1488-1489
Author(s):  
Thomas W. Shattuck ◽  
James R. Anderson ◽  
Neil W. Tindale ◽  
Peter R. Buseck
Keyword(s):  
Cluster Analysis ◽  
Chemical Reactivity ◽  
Large Data ◽  
Large Data Sets ◽  
Particle Analysis ◽  
Data Sets ◽  
Halogen Chemistry ◽  
Complete Study ◽  
Components Analysis ◽  
Automated Scanning

Individual particle analysis involves the study of tens of thousands of particles using automated scanning electron microscopy and elemental analysis by energy-dispersive, x-ray emission spectroscopy (EDS). EDS produces large data sets that must be analyzed using multi-variate statistical techniques. A complete study uses cluster analysis, discriminant analysis, and factor or principal components analysis (PCA). The three techniques are used in the study of particles sampled during the FeLine cruise to the mid-Pacific ocean in the summer of 1990. The mid-Pacific aerosol provides information on long range particle transport, iron deposition, sea salt ageing, and halogen chemistry.Aerosol particle data sets suffer from a number of difficulties for pattern recognition using cluster analysis. There is a great disparity in the number of observations per cluster and the range of the variables in each cluster. The variables are not normally distributed, they are subject to considerable experimental error, and many values are zero, because of finite detection limits. Many of the clusters show considerable overlap, because of natural variability, agglomeration, and chemical reactivity.

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