Multivariate Exploratory Techniques Research Articles

Cities’ Hands Are Tied: Short-Term Economic Impacts of COVID-19 on Natural Population Growth in Metropolitan Greece

To delineate new directions of urban development in a context of demographic shrinkage in Southern Europe, the present study illustrates a comparative analysis of the demographic balance in metropolitan Athens, Greece (1956–2021). The analysis delineates short-term and long-term dynamics of the natural population balance, considering the impact of the Great Recession and COVID-19 pandemic, and assuming a contemporary increase in gross mortality rates and a marked fertility reduction associated with birth postponement. To address such objectives, we have compared the natural growth of population (the ratio of the total number of births to deaths) at ten year intervals (1956, 1960, 1970, 1980, 1990, 2000, 2009, 2019, 2020, 2021) in 115 municipalities of metropolitan Athens, controlling for the local context. The empirical results of descriptive statistics, spatial analysis, correlation statistics, non-parametric inference, and exploratory multivariate techniques outline the indirect impact of COVID-19 on population dynamics, being in some ways additive to the already observed effects of the Great Recession, reinforcing demographic shrinkage in specific local contexts. The COVID-19 pandemic and the Great Crisis likely accelerated the typical outcomes (population aging and low fertility) of the second demographic transition in Greece. These dynamics are associated with more volatile (and possibly reduced) immigration flows and with enhanced emigration, fueling urban shrinkage and a progressive economic decline of metropolitan regions, as our evidence suggests for Athens. Additional research should ascertain the aggregate, indirect role of pandemics in population dynamics as a proxy of urban and regional decline in European regions exposed to long-term aging.

Assessment of Gualaxo do Norte River water quality (Minas Gerais, Brazil) affected by the dam breach of Fundão utilizing exploratory multivariate techniques.

At the end of 2015, the Fundão dam belonging to the Samarco S.A. mining company was ruptured, releasing a flood of mud into the Gualaxo do Norte River, which advanced into the Doce River. The aim of the present study was to apply exploratory multivariate approaches to water quality data obtained during sampling campaigns at the Gualaxo do Norte River during the dry and rainy seasons, between July 2016 and June 2017. A total of 27 locations along the river were sampled, covering unaffected areas and regions influenced by the tailings waste from the dam. Determinations of chemical, physical, and microbiological water quality parameters were performed. Application of principal component analysis (PCA) resulted in the first two components together explaining 39.49% and 37.91% of the total variance for the dry and rainy season data, respectively. In both cases, the PCA groups were related to variables such as turbidity and total solids, which both presented higher values in regions affected by the mud flow. These results are in agreement with those obtained by the Kohonen neural network method, where two-dimensional maps confirmed the samples according to the affected and unaffected area by the disaster.

Examining Metacognitive Strategy Preferences of Students at Different Reading Proficiency Levels

The purpose of this study was to evaluate the distribution of students with varying levels of reading competence according to their selection of metacognitive methods from the 2018 Programme for International Student Assessment (PISA) survey. The research group consisted of 6,890 pupils from the Republic of Turkey who participated in the PISA 2018 study. The data were analyzed using the multivariate exploratory technique of correspondence analysis. In comparison to developing readers, skilled readers favored the metacognitive processes of summarizing, understanding and remembering, and evaluating believability. Awareness of appropriate metacognitive reading strategies should be emphasized in order to increase the reading comprehension of developing readers.

The Essential Oil of Tunisian Halophyte Lobularia maritima: A Natural Food Preservative Agent of Ground Beef Meat.

This study was directed towards the investigation of the chemical composition and antimicrobial properties of the essential oil of Tunisian halophyte Lobularia maritime (LmEO). The antibacterial effects against major food-borne pathogenic and food spoilage bacteria were tested using the well diffusion method, followed by the determination of the minimum inhibitory (MIC) and bactericidal (MBC) concentrations. The essential oil has shown strong antimicrobial activity against eight pathogenic strains, which was attributed mostly to predominant constituents of the essential oil: benzyl alcohol, linalool, terpien-4-ol and globulol, as well as to synergistic effects of its major and minor constituents. Considering strong antimicrobial effects of the tested essential oil, it was further tested as a natural alternative to food preservatives, using minced beef meat as a model system. Minced beef meat was spiked with 0.019, 0.038, and 0.076% of the essential oil and stored during 14 days at 4 °C, monitoring its microbiological, physicochemical, and sensory properties. Chemical analyses revealed that meat treated with 0.076% of LmEO at underwent a significant decrease (p < 0.05) in primary and secondary lipid oxidation and reduced metmyoglobin accumulation compared with control samples. Furthermore, microflora proliferation in the meat model system spiked with 0.076% of LmEO was significantly (p < 0.05) reduced in comparison to control. In addition, two multivariate exploratory techniques, namely principal component analysis (PCA) and hierarchical analysis (HCA), were applied to the obtained data sets to describe the relationship between the main characteristics of the meat samples with and without essential oil addition. The chemometric approach highlighted the relationships between meat quality parameters. Overall, results indicated that the essential oil of Lobularia maritima deserves to be considered as a natural preservative in the meat industry.

Application of Multivariate Exploratory Techniques to Predict Kinematic Viscosity of Biodiesel from Vegetable and Algae Oils

Application of Multivariate Exploratory Techniques to Predict Kinematic Viscosity of Biodiesel from Vegetable and Algae Oils

Sulfated exopolysaccharides from Porphyridium cruentum: A useful strategy to extend the shelf life of minced beef meat

Sulfated exopolysaccharides (EPS) from Porphyridium cruentum strain were extracted and their antioxidant and anti-bacterial potentials were evaluated based on DPPH free radical, ABTS•+ radical cation and DNA nicking assays, and against four foodborne pathogenic bacteria, respectively. They showed also interesting functional, foaming and emulsion properties. Moreover, microbiological and chemical effects of EPS at 0.5, 1 and 2% on refrigerated minced beef meat were undertaken. Chemical analyses revealed that the treated meat underwent significant decrease (P < 0.05) of primary and secondary lipid oxidation. By the end of the storage period, exopolysaccharides at 2% reduced the metmyoglobin and carbonyl group accumulation compared to control samples and were more efficient (P < 0.05) against microflora proliferation. Furthermore, two multivariate exploratory techniques namely Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were applied successfully to all obtained data describing the main characteristics attributed to refrigerated meat samples. Overall, these findings indicated that EPS from P. cruentum are worthy being developed as functional and bioactive components for the meat industry.

A democracia representativa no Brasil: uma análise da atuação dos deputados federais frente aos índices de desenvolvimento de seus estados e a região geográfica que ocupam

Purpose – This study seeks to verify whether the performance of Brazilian Congressional Representatives is related to MHDI and GDP per capita indices and the regions they represent. Methodology – Regarding the performance of the parliamentarians, the data used were those made available by the Transparência Brasil portal and analyzed using the multivariate exploratory non-hierarchical cluster analysis technique K-means. Federative Units were divided into clusters according to the similarities they presented with respect to the variables that made up the analysis. Findings – After the analyses, we were able to determine that there is no relation of equivalence between the performance of representatives in Congress and the observed research development indices (MHDI and GDP per capita) with states of different regions and quite distinct conditions of development making up the same group of analysis. Originality/value – The researched data, or even the identification of transparency actions demonstrates the wide variety of analysis possibilities that are available in terms of discussions of the performance of political agents and their respective returns for the population. We would suggest that future studies can use other data or other reports displayed in the transparency portals of various spheres of government. Other research possibilities can be developed based on qualitative analyses of the effective representativity of the projects proposed by these representatives of the people.

What Happens in the City When Long-Term Urban Expansion and (Un)Sustainable Fringe Development Occur: The Case Study of Rome

This study investigates long-term landscape transformations (1949–2016) in urban Rome, Central Italy, through a spatial distribution of seven metrics (core, islet, perforation, edge, loop, bridge, branch) derived from a Morphological Spatial Pattern Analysis (MSPA) analyzed separately for seven land-use classes (built-up areas, arable land, crop mosaic, vineyards, olive groves, forests, pastures). A Principal Component Analysis (PCA) has been finally adopted to characterize landscape structure at 1949 and 2016. Results of the MSPA demonstrate how both natural and agricultural land-uses have decreased following urban expansion. Moreover, the percent ‘core’ area of each class declined substantially, although with different intensity. These results clearly indicate ‘winners’ and ‘losers’ after long-term landscape transformations: urban settlements and forests belong to the former category, the remaining land-use classes (mostly agricultural) belong to the latter category. Descriptive statistics and multivariate exploratory techniques finally documented the intrinsic complexity characteristic of actual landscapes. The findings of this study also demonstrate how settlements have expanded chaotically over the study area, reflecting a progressive ‘fractalization’ and inhomogeneity of fringe landscapes, with negative implications for metropolitan sustainability at large. These transformations were unable to leverage processes of settlement and economic re-agglomeration around sub-centers typical of polycentric development in the most advanced socioeconomic contexts.

Use of Endemic Date Palm (Phoenix dactylifera L.) Seeds as an Insoluble Dietary Fiber: Effect on Turkey Meat Quality

In order to enhance the quality of a meat product, turkey burgers with a low-fat and a high-fiber level were formulated by the incorporation of insoluble fibers from Tunisian Deglet Nour date seeds as insoluble fiber concentrate (IFC) at 3%, 5%, and 10% (w/w). Compared to Deglet Nour date seeds powder (DSP), physicochemical results revealed that IFC presented higher ( P &lt; 0.05) levels in carbohydrates at 88.85% and lower values of fat (5.94%), protein (3.81%), and ash (2.35%). For the technofunctional properties, IFC improved the oil-holding capacity (OHC) by 57.14% compared to DSP. IFC addition into turkey burgers was also instrumentally investigated by color (L ∗ , a ∗ , and b ∗ ) and textural parameters (hardness, cohesiveness, adhesiveness, and elasticity) and sensory attributes using a 5-point hedonic scale. Furthermore, IFC changed significantly the color of the formulated products. In addition, hardness and adhesiveness values of all experiments increased significantly ( P &lt; 0.05) with the increase of the incorporation levels compared to the control sample. Regarding sensory analysis, formulated with 5 % IFC, turkey burger samples were most appreciated by the panel with higher ( P &lt; 0.05) overall acceptability. Additionally, two multivariate exploratory techniques, namely, Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), were used to all obtained data describing the main characteristics attributed to refrigerated turkey meat samples. The applied chemometric approaches were useful in discriminating meat samples and therefore offer an approach to rely interrelationships between meat quality traits. Overall, the findings demonstrate the potential functional and economic utility of IFC as a promising ingredient for future healthy meat applications.

Background concentrations and quality reference values for potentially toxic elements in soils of Piauí state, Brazil.

The background concentration of potentially toxic elements (PTE) in soils is influenced by the parent material composition and soil forming processes. The soil natural concentration of PTE is a first step to establish regulatory levels for the monitoring of these elements in soils suspected of contamination. In the present study, we performed a natural background concentration survey of PTE in soils of the Piauí state, Brazil. The study provides the basis for establishing soil quality reference values (QRVs) for a large area (over 251,000km2) with different pedological features. A total of 262 geo-referenced soil samples (0.0-0.2m) were collected in areas relatively undisturbed by human activity. The concentrations of Ba, Cd, Co, Cr, Cu, Fe, Mo, Ni, Pb, Sb, V, and Zn were determined by ICP-OES. Univariate statistical methods and multivariate exploratory techniques were used to understand the relationship between soil characteristics, geological features, and PTE concentrations in soils. The mean background concentrations of PTE in the soils were generally lower than those reported in other countries and/or other Brazilian states, and followed the order: Fe > Ba > V > Cr > Cu > Pb > Zn > Ni > Pb > Co > Mo > Sb > Cd. The main factors governing the concentrations of PTE in soils were the parent material and the soil texture. The different geological features in the study area influenced the spatial distribution of PTE and divided the state into three regions presenting low, high, and intermediate values. Given this geological and pedological complexity, we proposed establishing three sets of QRV rather than a single QRV for the whole state to avoid misinterpretation regarding the investigation of areas suspected of contamination. This background concentration survey contains a wealth of information that provides the basis for the soil guideline values in the state and supports future research on the impact of anthropogenic activities in soil contamination.

Water Erosion Reduction Using Different Soil Tillage Approaches for Maize (Zea mays L.) in the Czech Republic

In today’s agriculture, maize is considered to be one of the major feed, food and industrial crops. Cultivation of maize by inappropriate agricultural practices and on unsuitable sites is connected with specific risks of soil degradation, mainly due to water erosion of the soil. The aim of this study was to evaluate the yielding parameters, fodder quality and anti-erosion efficiency of different methods of conservation tillage for maize in two areas (Jevíčko—JEV and Skoupý—SKO) with different climate and soil conditions in the Czech Republic in the period 2016–2018, using multivariate exploratory techniques such as principal component analysis (PCA) and factor analysis (FA). Four variants of soil tillage methods were analysed: Conventional Tillage (CT), two slightly different Strip-Till techniques (ST) and Direct Sowing (DS). The analysed parameters were: dry mass of the plants, height of the plants, starch content (SC), organic matter digestibility (OMD) and content of neutral detergent fibre (NDF), soil loss by erosion and surface runoff. The multivariate exploratory techniques PCA and FA significantly differed in two categories of techniques in both locations. The first category consists of soil conservation techniques (SCT): ST (JEV/SKO) and DS (JEV). These techniques are characterised by lower yields of dry mass, lower height of plants, forage quality equal to CT, but a high level of protection of the soil against erosion. The second category consists of CT (JEV and SKO) and partially of DS (SKO). These treatments are characterised by high dry mass production, higher plants, high forage quality, but a feeble capacity of protection of the soil against erosion. The results of the study confirm the presumption of the positive influence of introduction and application of new agronomical practices in the areas of interest and other areas with similar natural conditions in the sense of sustainable management for agricultural management of agricultural land for the conditions of the Czech Republic and therefore of Central and Eastern Europe. PCA and FA were used as an effective method for comprehensive evaluation of the use of STC in agricultural practice.

Changes in the soil's biological and chemical properties due to the land use

Increasing the soil productivity is challenged by the increasing biotic threat to plants and microorganisms, by the resistance to agrochemicals, and by the declining soil health. Soil management strategy is, therefore, aimed at erosion prevention and the minimisation of soil organic matter losses. A key factor in an agroecosystem is the appropriate biological stability. It is essential not only at present, but also for further sustainable agriculture. This study was based on the hypothesis that afforestation and conversion from arable land to permanent grassland improves the organic matter status and biological stability in the agroecosystem. The experiment was conducted from 2014 to 2018 in the Uhřice bio-corridor (Kroměříž region, the Czech Republic). Haplic Luvisol has been investigated for its basic biological and chemical properties after the arable land was converted to a natural vegetation system. The afforested segment (F), permanent grassland segment (G), and arable land segment (A) have been sampled in the upper soil horizon (0–0.30 m). Standard analytical methods were applied for the determination of the basic soil properties. A principal component analysis and factor analysis were used for interpreting the connection between the parameters of the soil organic carbon, the humic substances, the humic acids, and the fulvic acids, the agrochemical properties of the soil (the pH, the content of the nitrogen, phosphorus and potassium, etc.), and the soil biological properties (basal soil respiration (BSR), the ratios of the N/BSR, NG/BSR, etc.). After five years of investigation, the differences in the studied parameters were evident. The factor analysis and multivariate exploratory techniques showed that the soil properties were grouped based on the management into three different categories – F, G and A. The different land use directly influenced the quality and stability of the humic substances, basal soil respiration, and carbon and nitrogen utilisation. In comparison to the arable land, the forest and grassland were considered to have a higher accumulation potential of carbon and nitrogen. A negative correlation between the soil basal respiration (r = –0.95); total nitrogen (r = –0.93); total organic carbon (C&lt;sub&gt;ox&lt;/sub&gt;) content (r = –0.82); and partial Ca (r = –0.82) was found. A positive correlation (r = 0.80) between the humic substances (C-HS) and soil reaction (pH) was determined.

In-Between ‘Smart’ Urban Growth and ‘Sluggish’ Rural Development? Reframing Population Dynamics in Greece, 1940–2019

Multifaceted demographic dynamics have shaped population growth in Mediterranean Europe, reflecting a metropolitan cycle from urbanization to re-urbanization. To assess the distinctive impact of economic downturns on population dynamics, the present study illustrates the results of an exploratory analysis that assesses urban expansion and rural decline at various temporal scales in Greece, a peripheral country in southeastern Europe. Statistical analysis based on multivariate exploratory techniques outlined the persistent increase of regional populations, evidencing the distinctive role of agglomeration/scale with urbanization and early suburbanization phases (1940–1980) and accessibility/amenities with late suburbanization and re-urbanization phases (1981–2019). Recession accompanied (and, in some way, consolidated) the decline of agglomeration economies, leading to counter-urbanization in some cases. As an indirect result of counter-urbanization, the population increased more rapidly in low-density coastal areas with moderate accessibility and tourism specialization. Consistently, settlement expansion has altered the persistent gap in central and peripheral locations. A polarized urban hierarchy centered on the capital city, Athens, was replaced with a more diffused growth of medium-sized cities and attractive rural locations, depicting a new development path for lagging countries in the European Union and other socioeconomic contexts worldwide.

Effects of Ephedra alata extract on the quality of minced beef meat during refrigerated storage: A chemometric approach

The biopreservative effect of Ephedra alata aqueous extract (EAE), used at 0.156, 0.312 and 0.624%, on minced beef meat was evaluated by microbiological, physicochemical and sensory analyses during storage at 4 °C for 14 days. The results showed that EAE significantly (P < .05) delayed the formation of thiobarbituric acid-reactive substances and carbonyls and reduced the sulfhydryl loss in a dose-dependent manner, indicating that EAE had a protective effect against lipids and protein oxidation. Concomitantly, an increase of redness and loss of lightness and yellowness was observed. Furthermore, two multivariate exploratory techniques, namely Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) were applied to all obtained data describing the main characteristics attributed to refrigerated meat samples. During storage time, the used chemometric approaches were useful in discriminating meat samples, and therefore offers an approach to underlay connections between meat quality features. The obtained findings demonstrated the strong potential of EAE as a natural preservative in meat and meat products.

Winter Collection of the Underutilized Berry Corema Album (l.): New Insights on its Maturation Progression

Increasing interest in Corema album L. is raising due to the appealing white colour and potential health benefits related to its bioactive composition. White fruits production culminates in late August on coastal dunes, but fruits of various colours are present almost till flowering (late February). We undertook a preliminary physical-chemical characterisation (biometric, CIELab colour, pH, soluble solids content and titrable acidity) of a late fruit collection to disentangle maturity progression and to reveal latent qualities for future utilisation. Irrespective of fruit perceived colouration (white, translucent, brown, brown with black spots and black), the characterized high acidity (1-3 g.100 mL-1) is suggestive that over-mature fruits can still be further explored as food additives. Moreover, using a multivariate exploratory technique, we found a clear fruit’s maturation progression from white/translucent to black, a so-far unreported maturity stage. Addressing gaps in plant phenology and fruit’s maturity behaviour is needed before undertaking cultivation.

Changes over time in the spatial structure of fertility rates as a dynamic indicator of urban transformations

Since fertility varies largely over space responding to socioeconomic transformations, a spatially explicit analysis of birth rates may contribute to a refined understanding of the intimate linkage between demographic change and metropolitan growth in low-fertility countries, and especially in Europe. The present study investigates changes in the spatial structure of fertility levels over 60 years (1956–2016) in a Southern European metropolitan area (Athens, Greece) with the aim to quantify the impact of long- and short-term socioeconomic transformations on regional and local fertility patterns. A statistical approach integrating global and local Moran’s spatial autocorrelation indexes, non-parametric inference, and multivariate exploratory techniques was adopted to investigate the influence of a long-term urban cycle (urbanization, suburbanization, counter-urbanization, re-urbanization) and short-term economic downturns (expansion vs. recession) on the spatial structure of fertility rates. The empirical results of the present study suggest that local fertility in Athens responds to socioeconomic transformations reflecting a complete urban cycle. The spatial structure of local fertility is demonstrated to be a relatively stable feature of complex metropolitan systems, being influenced by social changes during medium-long time scales.

Comprehensive evaluation of radical scavenging, reducing power and chelating capacity of free proteinogenic amino acids using spectroscopic assays and multivariate exploratory techniques.

Among others, amino acids can inhibit oxidative processes through multiple pathways including inactivation of reactive oxygen species, scavenging free radicals, chelation of pro-oxidative transition metals, as well as reduction of hydroperoxides. Moreover, they can be a major target for oxidants as a result of their abundance in biological systems. The purpose of the present study is to examine the radical scavenging, reducing power and chelating capacity of the free proteinogenic amino acids, using several analytical assays based on different mechanisms and monitored via molecular UV-vis absorption spectrophotometry. In most of the assays, the highest antioxidant activity is rendered by Cys and Trp, known for their involvement in physiological radical reactions, followed by Tyr, Asn and Arg. The least reactive amino acids with respect to both radical scavenging and reducing power principle were Ala, Met, Thr and Val. The hierarchy of the amino acids based on their antioxidant activity is shifting, depending on the analytical assay employed. Results from the multivariate exploratory techniques-hierarchical cluster analysis and principal component analysis-could point out the methods that are most similar and best connected to each other, thus classifying the investigated amino acids according to their activity. Considering the results of chemometric techniques, the antioxidant methods that best discriminate between amino acids are DPPH bleaching and SORS assays. Not only the comprehensive study of antioxidant activity of amino acids is novel in this study but also the application of the sum of ranking differences to compare and rank the various antioxidant capacity assays. The obtained results will support the development of amino acids based multifunctional formulations with important physiologically relevant implications for both humans and animals, with a possible future use in the food industry.

Physicochemical characterization and quantification of bioactive compounds of Antrocaryon amazonicum fruits cultivated in Brazilian Amazonia

ABSTRACT In this study, we reported for the first time about the physicochemical characterization, as well as the bioactive compounds in the peel and pulp of A. amazonicum fruits of two varieties harvested in Northern Brazil (Pará State) from two harvest periods (beginning and end). The peel and pulp of A. amazonicum fruits presented high contents of water (75–89%) and total carbohydrates (5–12%), whereas low total energetic value ranges (41–92 kcal/100 g, wet basis). Regardless the variety of A. amazonicum fruits, phenolic compounds were the major bioactive compounds, and the peels accumulated high contents at the beginning of the harvest period (4884–6556 mg GAE/100 g, dry basis, db), and at the end for the pulps (1394–2855 mg GAE/100 g, db). The multivariate exploratory techniques evidenced that high contents of bioactive compounds are available in the peel at the beginning of the harvest period, while at the end for the pulps.

Population Age Structure, Complex Socio-Demographic Systems and Resilience Potential: A Spatio-Temporal, Evenness-Based Approach

The present study illustrates an original approach grounded on entropy theory and complex system thinking with the aim to investigate changes over time and space in population structure by age in Italy, in light of socioeconomic resilience and post-crisis recovery potential. Assuming that population structure may reflect different levels of resilience to exogenous shocks, a Pielou J evenness index was calculated on census data made available every 10 years (1861–2011) with the aim to identify compositional homogeneity (or heterogeneity) in the age structure of the Italian population. Trends over time in the Pielou J evenness index were identified using descriptive statistics, comparison with ancillary demographic indicators and multivariate exploratory techniques including principal component analysis. The empirical results allowed the identification of multiple dimensions of demographic transition in Italy, distinguishing two phases, the former encompassing a relatively long time period between 1861 and 1936, and the latter covering a shorter period between 1936 and 2011. A spatially-explicit analysis of Pielou J evenness indices applied to the population age structure of each Italian municipality at the latest survey (2017) finally provided a comprehensive overview of the demographic characteristics likely influencing the resilience potential of local districts. The empirical evidence outlined the consolidation of a coastal–inland divide as a result of the complex linkage between demographic dynamics and local background contexts.

Participation of the autonomic cardiac system in dogs with chronic myxomatous degeneration of the mitral valve

ABSTRACT An exploratory multivariate analysis of factors of echocardiographic variables and those of the Holter test of 38 dogs with MVMD staged in three classes (class 1a, class 1b, class 2) of congestive heart failure proposed by the ISACHC. The purpose of this analysis was learning the processes that would explain the behavior of the variables described, using exploratory multivariate techniques of factors. Five independent factors were determined (PNS to SF) which altogether explain 82.17% of the shared variance of the data. It was identified that among the five factors, the first process (PNS) is the first factor in importance, recruiting the highest percentage of variance (37.96%) and represents the participation of the cardiac autonomic nervous system.