An analysis of the element content of lichens from the Northwest Territories, Canada

1980 ◽  
Vol 58 (19) ◽  
pp. 2073-2089 ◽  
Author(s):  
K. J. Puckett ◽  
E. J. Finegan
Keyword(s):  
Northwest Territories ◽  
Univariate Analysis ◽  
Principal Component ◽  
Element Content ◽  
Anthropogenic Sources ◽  
Underlying Structure ◽  
Single Element ◽  
Crustal Rock ◽  
Multiple Discriminant Analysis ◽  
Element Analysis

The results of a survey of the element content of saxicolous and terricolous lichens collected from the Northwest Territories, Canada, are summarized. Fourteen lichen species were collected from 45 sites and the lichens were analysed for 20 elements by instrumental neutron activation and X-ray fluorescence.An enrichment factor (EF) was calculated for each element analysis. The elements aluminium, chromium, iron, sodium, titanium, and vanadium had mean EF values of 1–5 for all species. These low EF values indicated that, relative to average values for crustal rock, there was no enrichment of these elements in the lichens concerned. For other elements (chlorine, lead, and sulphur) consistently higher EF values were obtained. These higher values were interpreted in terms of (a) differing methods of element accumulation, (b) sources of elements both natural and anthropogenic other than crustal rock and (or) soil, and (c) marked deviations of the actual substrate concentrations from the average crustal-rock concentrations used.The underlying structure of the data from some species was investigated using ordination techniques. These techniques provided some description of the element associations within the lichen thallus. These element associations were examined in relation to sources external to the plant. A principal component analysis was carried out on the data for each of three species, Cetraria cucullata, C. nivalis, and Cladina stellaris. In all cases, the first five principal components explained 81–89% of the variation in the data. One component which had high weightings for aluminium, scandium, and vanadium (with or without iron, nickel, and titanium) was common to all three species. Similarly, a second component with high weightings for calcium (with or without magnesium and potassium) was a consistent feature of each analysis. These and other components were considered in the context of lichen enrichment from crust-derived particulates, the marine aerosol, and certain anthropogenic sources. The high percentage of variation explained by the first five components strongly indicated that the major element sources contributing to this variation were considered. Nonmetric multidimensional scaling supported the principal component solution.There was considerable interspecific variation in the element content of the lichens. Univariate analysis of variance did not show any significant differences between the element content of Cladina arbuscula, C. rangiferina, and C. stellaris or any differences between Cetraria cucullata and C. nivalis on the basis of any single element. However, multiple discriminant analysis did show that the species mentioned could be distinguished (~ 90% discrimination) when all the elements were compared simultaneously. The discrimination between the Cladina spp. was based on the relative efficiency of these lichens in the accumulation of iron, scandium, titanium, and vanadium.

scholarly journals On the Move: Principal Components of the Functions and Experiences of Mobile Music Listening

2021 ◽  
Vol 4 ◽  
pp. 205920432110328
Author(s):  
Mia Kuch ◽  
Clemens Wöllner
Keyword(s):  
Life Experiences ◽  
Principal Component ◽  
Underlying Structure ◽  
Music Listening ◽  
Social Dimensions ◽  
Online Questionnaire ◽  
Mood Management ◽  
Five Dimensions ◽  
Mobile Music ◽  
Deep Listening

Mobile music listening is widely recognized as an integral part of everyday music use. It is also a rather peculiar experience, since the listeners are surrounded by strangers in public and at the same time engaged in a solitary and private activity. The current study aimed at investigating the functions and experiences of mobile listening with a quantitative online questionnaire, and collected further information about mobile listening situations and listening habits. Among respondents ( n = 203), 89% reported listening to music while being on the move. We found mood-related and cognitive functions to be most prevalent (e.g., enhancing mood, relaxation, prevention of being bored), whereas least important functions relate to social dimensions (e.g., feeling less lonely, feeling less watched). Regarding experiences of mobile music, respondents most commonly adapted their mood to the music and lost touch with the current surroundings. A principal component analysis on ratings of functions and experiences resulted in an underlying structure of five dimensions, representing different levels of involvement: (1) Mood Management comprises functions to satisfy individual needs; (2) Absorption and Aestheticization encompasses deep listening experiences and altered perception of the surroundings; (3) Social Encapsulation and Self-Focus describe the distancing of oneself and changes in attention; (4) Distraction and Passing Time include the prevention of being bored and making time pass faster; and (5) Auditory Background is defined by a non-attentive and rather unaffected music listening. These results highlight the immersiveness of mobile music listening. By creating an individual soundworld, listeners distance themselves from the surroundings aurally and mentally, and modify their attention, perception, moods, and emotions, leading to an improvement of daily life experiences while moving.

scholarly journals A Strategy for Dimensionality Reduction and Data Analysis Applied to Microstructure–Property Relationships of Nanoporous Metals

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1822
Author(s):  
Norbert Huber
Keyword(s):  
Machine Learning ◽  
Dimensionality Reduction ◽  
Work Hardening ◽  
Large Range ◽  
Scaling Law ◽  
Principal Component ◽  
Underlying Structure ◽  
Structure Property ◽  
Work Hardening Rate ◽  
Nanoporous Metals

Nanoporous metals, with their complex microstructure, represent an ideal candidate for the development of methods that combine physics, data, and machine learning. The preparation of nanporous metals via dealloying allows for tuning of the microstructure and macroscopic mechanical properties within a large design space, dependent on the chosen dealloying conditions. Specifically, it is possible to define the solid fraction, ligament size, and connectivity density within a large range. These microstructural parameters have a large impact on the macroscopic mechanical behavior. This makes this class of materials an ideal science case for the development of strategies for dimensionality reduction, supporting the analysis and visualization of the underlying structure–property relationships. Efficient finite element beam modeling techniques were used to generate ~200 data sets for macroscopic compression and nanoindentation of open pore nanofoams. A strategy consisting of dimensional analysis, principal component analysis, and machine learning allowed for data mining of the microstructure–property relationships. It turned out that the scaling law of the work hardening rate has the same exponent as the Young’s modulus. Simple linear relationships are derived for the normalized work hardening rate and hardness. The hardness to yield stress ratio is not limited to 1, as commonly assumed for foams, but spreads over a large range of values from 0.5 to 3.

scholarly journals Changes in pigment, spectral transmission and element content of pink chicken eggshells with different pigment intensity during incubation

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1825 ◽  
Author(s):  
Yue Yu ◽  
Zhanming Li ◽  
Jinming Pan
Keyword(s):  
Spectral Characteristics ◽  
Element Content ◽  
Spectral Transmission ◽  
Element Analysis ◽  
Light Passing ◽  
Visible Wavelength Range ◽  
Chicken Eggshell ◽  
Eggshell Pigmentation ◽  
Light Medium ◽  
Pink Pigment

Objective.The objective of this study was to investigate changes in pigment, spectral transmission and element content of chicken eggshells with different intensities of pink pigment during the incubation period. We also investigated the effects of the region (small pole, equator and large pole) and pink pigment intensity of the chicken eggshell on the percent transmission of light passing through the chicken eggshells.Method.Eggs of comparable weight from a meat-type breeder (Meihuang) were used, and divided based on three levels of pink pigment (light, medium and dark) in the eggshells. During the incubation (0–21 d), the values of the eggshell pigment (ΔE,L∗,a∗,b∗) were measured. The percent transmission of light for different regions and intensities of eggshell pigmentation was measured by using the visible wavelength range of 380–780 nm.Result.Three measured indicators of eggshell color, ΔE,L∗anda∗, did not change significantly during incubation. Compared with other regions and pigment intensities, eggshell at the small pole and with light pigmentation intensity showed the highest percent transmission of light. The transmission value varied significantly (P< 0.001) with incubation time. The element analysis of eggshells with different levels of pink pigment showed that the potassium content of the eggshells for all pigment levels decreased significantly during incubation.Conclusion.In summary, pigment intensity and the region of the eggshell influenced the percent transmission of light of eggshell. Differences in the spectral characteristics of different eggshells may influence the effects of photostimulation during the incubation of eggs. All of these results will be applicable for perfecting the design of light intensity for lighted incubation to improve productivity.

Temperature effect on the tensile behaviors of carbon/polyimide composite laminate

2016 ◽  
Vol 231 (24) ◽  
pp. 4592-4602 ◽  
Author(s):  
Liang Li ◽  
Purong Jia ◽  
Wenge Pan
Keyword(s):  
Temperature Effect ◽  
Composite Laminates ◽  
Three Dimensional ◽  
Thermomechanical Coupling ◽  
Single Element ◽  
Element Analysis ◽  
Open Hole ◽  
Dimensional Finite Element ◽  
Different Temperatures ◽  
Three Dimensional Finite Element

Experimental and numerical investigations were carried out to study the temperature effect on the stiffness, strength, and failure behaviors of carbon/polyimide composite laminates. Both unnotched laminates and open-hole laminates were tested under tension load at three temperatures (room temperature, 200 ℃, and 250 ℃). A three-dimensional finite element analysis was carried out to study the thermomechanical coupling behavior in the notched laminate. The model considers each layer and interface as a single element in the thickness direction so that in-plane stress and interlaminar stress could be analyzed in the model. The stresses around the open-hole changing characteristics with the temperature and tensile loading have been discussed in detail. Failure analysis was carried out to predict the residual strength of the notched laminates at different temperatures. Compared to the experimental data, the numerical results have an excellent agreement.

Youth athletes' sustained involvement in elite sport: An exploratory examination of elements affecting their athletic participation

2018 ◽  
Vol 13 (5) ◽  
pp. 658-673 ◽  
Author(s):  
Elodie Wendling ◽  
Meredith Flaherty ◽  
Michael Sagas ◽  
Kyriaki Kaplanidou
Keyword(s):  
Peer Relationships ◽  
Extrinsic Motivation ◽  
Sport Participation ◽  
Principal Component ◽  
Youth Sport ◽  
Underlying Structure ◽  
Elite Sport ◽  
Cross Sectional ◽  
Youth Athletes ◽  
The Usa

In this exploratory study, we first intended to identify the underlying structure of components affecting the sport participation of 1258 elite youth athletes from the USA through a principal component analysis of 23 items related to motives and barriers to participation and created for this study. A six-component solution was proposed, including college and professional aspirations and competence beliefs, coach and peer relationships, pressures from parents and coach, intrinsic and self-determined extrinsic motivation, external barriers, and non–self-determined extrinsic motivation. Noteworthy differences by age, gender, and race on those retained components were also reported. Lastly, results of hierarchical regression analyses indicated that 28% of the variance in sport enjoyment was explained by all retained components. Given the rapid growth of travel teams, this study provides a timely cross-sectional and multisport assessment of the state of elite youth sport in the USA. In consideration of optimistic outcomes observed in this study compared to alarming attrition trends commonly found in the elite youth sport environment, this study may serve as a reference as to the elements that influence sustained participation that is indispensable in today's youth sport landscape. Results also provided important theoretical contributions with respect to motivational processes underlying elite sport participation. Practical implications with regards to the influence of intrapersonal, interpersonal, and barrier elements on elite sport participation are also presented.

scholarly journals Sediment Metal Contamination, Bioavailability, and Oxidative Stress Response in Mangrove Avicennia marina in Central Red Sea

2021 ◽  
Vol 9 ◽  
Author(s):  
Abdullahi Bala Alhassan ◽  
Mohammed Othman Aljahdali
Keyword(s):  
Antioxidant Enzyme ◽  
Red Sea ◽  
Anthropogenic Activities ◽  
Sediment Quality ◽  
Principal Component ◽  
Avicennia Marina ◽  
Anthropogenic Sources ◽  
Antioxidant Enzyme Activities ◽  
Metal Concentrations ◽  
Mangrove Ecosystems

Anthropogenic activities have been on the increase in the urban environment and have led to contamination of the environment with toxic metals. However, mangrove plants’ response to heavy metal stress due to anthropogenic activities explains the metal bioavailability and its potential ecotoxicological effect. We carried out a multi-approach study to investigate i) if the concentrations of metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Pb, Sr, and V) in mangroves at the central Red Sea are due to the anthropogenic influence and are above the sediment quality guidelines and ii) if an increase in metal concentration influences height and antioxidant enzyme (catalase, CAT; glutathione S-transferase, GST; and superoxide dismutase, SOD) activities in Avicennia marina. There were significant variations (p &lt; 0.05) in metal concentrations and antioxidants across the six mangrove ecosystems with higher concentrations at Al Lith (LT) and south Jeddah (SJ). Even though the concentrations of metals in mangrove leaves are slightly higher in LT than SJ, principal component analysis showed that higher concentrations of Cr, Co, Zn, Cd, and Pb in mangrove leaves from SJ influence higher antioxidant enzyme activities and the lowest average mangrove height (2.01 m). This suggests that higher metal concentrations be factors for the biggest stress in these mangrove ecosystems. However, among the 13 metals, Cr (82.07 mg/kg), Cu (41.29 mg/kg), and As (10.30 mg/kg) in sediments have values within the ERL range of probable effect, while Ni (53.09 mg/kg) was above the ERM threshold. Hence, there is need to focus on monitoring these metals in mangrove sediments and their anthropogenic sources.

scholarly journals Submicron and Ultrafine Particles in Downtown Rome: How the Different Euro Engines Have Influenced Their Behavior for Two Decades

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 894
Author(s):  
Gaetano Settimo ◽  
Maria Eleonora Soggiu ◽  
Marco Inglessis ◽  
Maurizio Manigrasso ◽  
Pasquale Avino
Keyword(s):  
Ultrafine Particles ◽  
Principal Component ◽  
Submicron Particles ◽  
Anthropogenic Sources ◽  
Health Issues ◽  
Previous Decade ◽  
Big City ◽  
Removal Processes ◽  
Different Sources

Today, submicron particles are recognized as the new target in environmental sciences and human health issues as well. Their level in urban air is strongly affected by anthropogenic sources, i.e., domestic heating and autovehicular traffic, but the availability of large datasets represents a limit in the knowledge both of the behavior and of the relative levels. This paper would like to highlight the role of these two anthropogenic sources in a big city such as Rome in the particle formation/removal processes in the range 18–750 nm using a Scanning Mobility Particle Analyser (SMPS). The investigation starts from data collected in the previous decade (2010) and analyzes the role played by different Euro (0–6) engines on the particle levels as well as the responsibility of different biomass burning in this issue. Furthermore, a chemometric approach (Cluster Analysis, CA, and Principal Component Analysis, PCA) has allowed the identification of three different clusters, strongly dependent on the accumulation and nucleation modes of the Ultrafine Particles. On the other hand, the PCA demonstrated a scatter distribution in December larger than that in October, justified by the different sources present in these periods.

Finite Element Modeling of Effect of Adhesive Layer and Carrier Thickness Used for Strain Gauge Mounting

2015 ◽  
Vol 1119 ◽  
pp. 828-832
Author(s):  
K. Vadivuchezhian ◽  
K. Subrahmanya ◽  
N. Chockappan
Keyword(s):  
Finite Element ◽  
Strain Gauge ◽  
Adhesive Layer ◽  
Element Model ◽  
Strain Gauges ◽  
Single Element ◽  
Metal Foil ◽  
Engineering Structures ◽  
Element Analysis ◽  
Typical Strain

Metal foil strain gauges are most widely used for the stress analysis in engineering structures. Typical strain gauge system includes strain sensitive grid, carrier material, and adhesive layer. Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. In the present work, a Finite Element Model is developed in order to study the effect of both adhesive layer and carrier thickness on strain measurements while using strain gauges. To understand the behavior of the adhesive material, mechanical characterization is done on bulk adhesive specimen. Finite Element Analysis (FEA) is carried out with different materials namely epoxy and polyurethane. Initially a single element foil loop is considered for the analysis and further this is extended to metal foil strain gauge with nine end-loops. Finally, the strain variation through thickness of adhesive layer, carrier and strain sensitive grid is obtained from FEA. The results thus obtained are compared with analytical results from Basic Strength of Materials approach.

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