Principal Component Analysis Research Articles

Effective relax acquisition: a novel approach to classify relaxed state in alpha band EEG-based transformation

A relaxed state is essential for effective hypnotherapy, a crucial component of mental health treatments. During hypnotherapy sessions, neurologists rely on the patient’s relaxed state to introduce positive suggestions. While EEG is a widely recognized method for detecting human emotions, analyzing EEG data presents challenges due to its multi-channel, multi-band nature, leading to high-dimensional data. Furthermore, determining the onset of relaxation remains challenging for neurologists. This paper presents the Effective Relax Acquisition (ERA) method designed to identify the beginning of a relaxed state. ERA employs sub-band sampling within the Alpha band for the frequency domain and segments the data into four-period groups for the time domain analysis. Data enhancement strategies include using Window Length (WL) and Overlapping Shifting Windows (OSW) scenarios. Dimensionality reduction is achieved through Principal Component Analysis (PCA) by prioritizing the most significant eigenvector values. Our experimental results indicate that the relaxed state is predominantly observable in the high Alpha sub-band, particularly within the fourth period group. The ERA demonstrates high accuracy with a WL of 3 s and OSW of 0.25 s using the KNN classifier (90.63%). These findings validate the effectiveness of ERA in accurately identifying relaxed states while managing the complexity of EEG data.Graphical abstract

Novel CAD Diagnosis Method Based on Search, PCA, and AdaBoostM1 Techniques

Background: Cardiovascular diseases (CVDs) are the primary cause of mortality worldwide, resulting in a growing number of annual fatalities. Coronary artery disease (CAD) is one of the basic types of CVDs, and early diagnosis of CAD is crucial for convenient treatment and decreasing mortality rates. In the literature, several studies use many features for CAD diagnosis. However, due to the large number of features used in these studies, the possibility of early diagnosis is reduced. Methods: For this reason, in this study, a new method that uses only five features—age, hypertension, typical chest pain, t-wave inversion, and region with regional wall motion abnormality—and is a combination of eight different search techniques, principal component analysis (PCA), and the AdaBoostM1 algorithm has been proposed for early and accurate CAD diagnosis. Results: The proposed method is devised and tested on a benchmark dataset called Z-Alizadeh Sani. The performance of the proposed method is tested with a variety of metrics and compared with basic machine-learning techniques and the existing studies in the literature. The experimental results have shown that the proposed method is efficient and achieves the best classification performance, with an accuracy of 91.8%, ever reported on the Z-Alizadeh Sani dataset with so few features. Conclusions: As a result, medical practitioners can utilize the proposed approach for diagnosing CAD early and accurately.

Using subtle variations in groundwater geochemistry to identify the proximity of individual geological structures: a case study from the Grimsel Test Site (Switzerland)

Understanding groundwater flow and the evolution of groundwater chemistry in networks of fractures in crystalline rock is of fundamental interest for geothermal projects, nuclear waste disposal, and groundwater resources. Groundwater chemistry at a given location is typically conceived of being of a specific ‘type’ (e.g. meteoric, juvenile, connate, marine), with associated chemical types controlled through water-rock interactions. Minor chemical variations between groundwater sample locations with the same chemical type are generally considered as ‘noise’ in the geochemical data. Here, we argue that this noise contains useful information on the mineral phases encountered by the groundwater as it travels through specific flow pathways. We analyse the spatial variability of groundwater chemistry around the Grimsel Test Site (GTS), Switzerland, where groundwater is hosted in two lithologies: the Central Aar Granite and the Grimsel Granodiorite, where flow occurs predominantly in a fracture network created by brittle reactivation of ductile shear zones. Groundwater chemistry is analysed using principal component and hierarchical cluster analyses, which identify two groundwater types based on their chemistry. The primary control on groundwater type is the host rock lithology (granite/granodiorite). While the spatial variability of groundwater chemistry within each of the two lithologies is small, statistical analysis of the data shows similar groundwater chemistry in borehole intervals that are crosscut by similar geological structures, implying a structural control on groundwater chemistry. Our research shows that subtle chemical variations in groundwater provide information on fracture network connectivity and the proximity of geological features, that specific volumes of groundwater has interacted with. Thematic collection: This article is part of the Sustainable geological disposal and containment of radioactive waste collection available at: https://www.lyellcollection.org/topic/collections/radioactive

Population genetics of caribou in the Alaska-Yukon border region: implications for designation of conservation units and small herd persistence

AbstractBetter knowledge of genetic relationships between the Fortymile caribou herd and its neighbors is needed for conservation decision-making in Canada. Here, we contribute the first fine-scale analysis of genetic population structure in nine contiguous caribou herds at the geographic boundaries between Barren-ground and Northern Mountain caribou, and at the Alaska-Yukon border. Using pairwise differentiation metrics, STRUCTURE, and discriminant analysis of principal components (DAPC) to analyze 15 microsatellite loci in 379 caribou, we found complex patterns of genetic differentiation. The Fortymile was the only herd assigned to more than one genetic cluster, indicative of its history as a larger herd whose range expansions and gene flow to other herds were likely important to maintaining diversity across a functioning genetic metapopulation. Some small herds (Chisana, Klaza, and White Mountains) were genetically distinct, while others (Hart River, Clear Creek, Mentasta) exhibited little differentiation from herds they occasionally overlap, including herds assigned to different conservation units (DUs). This genetic connectivity does not result from demographic connectivity, as episodic contact during rut, rather than herd switching, is the likely mechanism. Unusually, one small herd (White Mountains) maintained genetic differentiation despite rut overlap with Fortymile. Our data reveal that some herds with different ecological and behavioral attributes are demographically independent but nonetheless genetically connected. Thus, we suggest that managing caribou for an appropriate level of genetic connectivity, while also supporting herd persistence, will be essential to conserve caribou genetic diversity in the region.

Impact of salt content on Douchi metabolites: biogenic amines, non-volatile compounds and volatile compounds.

The excessive salt intake associated with Douchi has become a topic of controversy. Addressing this concern and enhancing its market competitiveness necessitates the application of salt reduction fermentation in Douchi. Therefore, to promote the application of salt reduction fermentation in Douchi, a comprehensive study was undertaken aiming to investigate the differences in biogenic amines, volatile compounds and non-volatile compounds in Douchi with varying salt content. The findings unequivocally demonstrate that salt hampers the formation of metabolites in Douchi. As the salt content increased, there was a significant decrease (P < 0.05) in the levels of total acid, amino-type nitrogen and free amino acids in Douchi. Notably, when the salt content exceeded 80 g kg-1, there was a substantial reduction (P < 0.05) in putrescine, lactic acid and malic acid levels. Similarly, when the salt content surpassed 40 g kg-1, β-phenethylamine and oxalic acid levels exhibited a significant decline (P < 0.05). Furthermore, the results of E-nose and principal component analysis based on headspace solid phase microextraction gas chromatography-mass spectrometry revealed notable discrepancies in the volatile compound content between Douchi samples with relatively low salt content (40 and 80 g kg-1) and those with relatively high salt content (120, 160 and 200 g kg-1) (P < 0.05). By employing partial least squares discriminant analysis, eight distinct volatile compounds, including o-xylene, benzaldehyde and 1-octen-one, were identified. These compounds exhibited higher concentrations in Douchi samples with relatively low salt content (40 and 80 g kg-1). The sensory results showed that Douchi samples with lower salt content exhibited higher scores in the soy sauce-like and Douchi aroma attributes. In conclusion, this study significantly enhances our understanding of the impact of salt on metabolites in Douchi and provides invaluable insights for the development of salt reduction fermentation in this context. © 2024 Society of Chemical Industry.

Phenological, Pomological, Biochemical and Physical Characteristics of Siirt Pistachio Variety (Pistacia vera L.) in Five Different Ecologies of Southeast Anatolia-Türkiye

ABSTRACT This study was conducted on Siirt Pistachio variety (Pistacia vera L.) grown in five different locations (Kahramanmaraş, Pazarcık, Gaziantep, Ceylanpınar and Siirt) for two years (2017 and 2018). Phenological (bud burst, beginning of flowering, full-bloom, and beginning of leafing end of flowering), pomological (fruit size, fruit weight, and color parameters), physical (split, unsplit fruit ratios, empty and full fruit ratio) and biochemical (total phenolics, flavonoids, antioxidant activity, and fatty acids) analyses were conducted. Total protein contents varied between 18.55% (Ceylanpınar) and 19.45% (Gaziantep); fatty acid contents between 52.80% (Siirt) and 54.25% (Gaziantep); saturated fatty acid ratios between 10.44% (Gaziantep) and 11.58% (Pazarcık); unsaturated fatty acid ratios between 88.42% (Pazarcık) and 89.56% (Gaziantep); saturated fatty acid/unsaturated fatty acid ratios between 7.64% (Pazarcık) and 8.58% (Gaziantep); total phenolics between 18.91 (Ceylanpınar) and 23.04 mg GAE/g; total flavonoids between 7.34 (Ceylanpınar) and 10.23 mg QE/g; antioxidant activity values between between 1.65 (Siirt) and 3.25 IC50 µg/ml (Kahramanmaraş). Principal component analysis revealed that four components had eigenvalues greater than 1. The first two components explained 64.6% of total variation. Oleic (−0.98) and linoleic (0.91) acids were the most effective parameters on the first component and kernel weight, a*, protein, arachidic, gonolic acids, Mg, P and Zn were the most effective parameters on the second component. Present findings can guide new studies to be done with this species.

Self-Adaptive Incremental PCA-Based DBSCAN of Acoustic Features for Anomalous Sound Detection

In modern industry, maintaining continuous machine operations is important for improving production efficiency and reducing costs. Therefore, the smart technology of acoustic monitoring to detect anomalous machine conditions earlier before breakdowns works as part of predictive maintenance and is applied not only in industry fault detection but also in safety monitoring and surveillance systems. This paper proposes a self-adaptive unsupervised machine learning algorithm with dimension-reduction technology to detect anomalous sounds after extracting acoustic machine features. Technically, the automatic EPS calculation algorithm-based genetic algorithm optimizes the automatic clustering algorithm’s configuration for incremental principal component analysis and density-based spatial clustering algorithms with noise. IPCA is enhanced by the sequential Karhunen–Loeve (SKL) algorithm, and the condensation algorithm works as the second layer of the algorithm to reduce the number of effective components. This architecture could select an optimized set of parameters based on different test environments and keeps performance quality with fewer computational requirements. In the experiments, 228 sets of normal sounds and 100 sets of anomaly sounds are used. The sound files are collected from the same machine type (stepper motors) at a real plant site. We compare the proposed algorithm with K-means++, one-class SVM, agglomerative clustering, DCGAN and DCNN-Autoencoder, and this new algorithm performs best, with an AUC of 0.84 and the shortest execution time. The algorithm is generic and can be applied to detect anomalies in machines to provide early warning to people to avoid serious accidents or disasters.

LC-MS Lipidomic Analysis of Macrophages

Currently, an increasing incidence of cardiovascular diseases is observed in the population. Factors contributing to their development are obesity and pro-inflammatory processes occurring in the adipose tissue. Macrophages, cells of the non-specific immune system, which can be divided into pro-inflammatory and anti-inflammatory, play a significant role in these processes. For a better understanding of these phenomena, it is necessary to analyze the lipidome of macrophages of the two mentioned groups. The presented work was focused on the optimization of selected parameters of the LC-MS method for the analysis of 71 lipids from 16 lipid classes. Best results were achieved with column Acquity UPLC BEH C18 (1.7 µm, 2.1 mm × 100 mm) operating at the flow rate of 300 μL min–1 and temperature of 55 °C. The optimal desolvation temperature was 350 °C and the gradient elution started at 0 % of solvent B in the mobile phase. Retention dependencies were characterized for individual lipid classes. They were successfully fitted with a linear model (R2 &gt; 0.99) and subsequently used to confirm the accuracy of lipid identification. The optimized LC-MS method was also used to analyze the real samples of macrophages isolated from the adipose tissue of kidney donors. Samples were provided by Institute for Clinical and Experimental Medicine. The principal component analysis gave insight into the division of macrophages according to their type. The volcano plot showed a significant increase in the concentration of five lipids in the case of pro-inflammatory macrophages.

Spike and slab Bayesian sparse principal component analysis

Spike and slab Bayesian sparse principal component analysis

Landscape influences on thermal sensitivity and predicted spatial variability among brook trout streams in the southeastern USA

AbstractWarming water temperatures as a result of climate change pose a major threat to coldwater organisms. However, the rate of warming is not spatially uniform due to surface‐ground‐water interactions and stream and watershed characteristics. Coldwater habitats that are most resistant to warming serve as thermal refugia and identifying their locations is critical to regional aquatic conservation planning. We quantified the thermal sensitivity of 203 streams providing current and potential habitat for brook trout (Salvelinus fontinalis) across nearly 1000 linear km of their native range in the southern and central Appalachian Mountains region, USA, and characterized their spatial variability with landscape variables available in the National Hydrography Dataset. Using the Bayesian framework, we calculated the maximum slope of the logistic function relating paired weekly mean air temperature and stream temperature as an index of stream thermal sensitivity. Streams differed greatly in thermal sensitivity and those with more resistant water temperature regimes (i.e., thermal refugia) were consistently characterized by southerly latitudes and groundwater input. Landscape variables derived from a principal component analysis explained 16% of the variation in thermal sensitivity, indicating that the existing landscape variables were modestly successful in explaining spatial thermal heterogeneity. Using our model and spatial interpolation, we predicted thermal sensitivity at 8695 stream segments potentially suitable for brook trout in the study region. Thermal refugia were more common southward presumably due to higher elevations, but elsewhere they were also clustered at finer spatial scales. Our analysis informs prioritizing habitat conservation and restoration of this native salmonid and other aquatic organisms that depend on coldwater habitats in a warming world.

Meat Characteristics, Expression of Myosin Heavy Chain and Metabolism-Related Genes in Thai Native Pigs

This study investigated the meat quality, expression of myosin heavy chain (MyHC) and metabolism-related genes, ribonucleotides and fatty acids in Longissimus thoracis of Thai native pigs (TNPs) from different geographical regions (GR). Forty-one 9–10-month-old castrated TNPs (BW 60 kg), consisting of 18, 11 and 12 pigs from Northern (NT), Southern (ST) and Northeastern (NE) regions, respectively, were slaughtered. GR did not affect (p &gt; 0.05) the expression of MyHC, phosphoglycerate mutase 1, cytosolic glycerol-3-phosphate dehydrogenase, triosephosphate isomerase 1 and adipocyte fatty acid binding protein genes. The trend of MyHC was MyHC IIx &gt; MyHC IIb &gt; MyHC IIa &gt; MyHC I. The NT loin had higher (p &lt; 0.05) glycogen, C18:2n6, C20:4n6 and cooking loss, lower inosine, inosine monophosphate and hypoxanthine and a shorter sarcomere length than the ST and NE loins. The ST loin had a lower (p &lt; 0.05) a* compared to other loins. Principal component analysis established significant relationships between the TNP and specific meat quality traits. This finding suggests that GR affected the meat quality, ribonucleotides and selected fatty acids in TNPs. These results provide relevant information that can be used to optimize the use of Thai native pork.

Key Aroma Differences in Volatile Compounds of Aged Feng-Flavored Baijiu Determined Using Sensory Descriptive Analysis and GC×GC–TOFMS

Sensory descriptive analysis of aged feng-flavored Baijiu liquor indicated notable differences in samples of different ages. The samples of freshly distilled Baijiu and those with shorter storage times exhibit bran and fresh green flavors, whereas, with increasing storage time, honey, sweet, and floral fragrances are gradually enhanced. Samples of feng-flavored Baijiu were prepared using headspace solid-phase microextraction, followed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry. A total of 496 compounds were identified in all samples, mainly categorized as 14 groups of substances, including esters and aldehydes. Interestingly, 42 of these substances were found in Feng-flavored Baijiu for the first time. Chemometrics was used to analyze the key differential compounds. First, 143 differential compounds closely related to aging were preliminarily screened, and principal component analysis revealed that these compounds were separated by baijiu age. Then, 65 differential compounds were selected by partial least squares discriminant analysis. Furthermore, 43 key differential compounds were selected by combined analysis with variable importance in projection and Pearson correlation coefficients. Partial least squares regression was used to study the correlation between the sensory properties and key differential compounds, and the results indicated that most compounds were closely related to the aging period of the Baijiu. The results of this study provide a theoretical basis and reference for flavor research on feng-flavored Baijiu.

An Evaluation of the Radioactive Content of Ashes Obtained from the Use of Fuels from Recycled Materials by Co-Processing in the Cement Industry

The co-processing of different wastes as fuels in the manufacture of cement clinker not only meets the objectives of a circular economy but also contributes to the reduction in CO2 emissions in the manufacture of Portland cement. However, waste used as alternative fuels, such as sludge or organic-rich residues, may contain naturally occurring radionuclides that can be concentrated during the combustion process. In this study, the presence of natural radionuclides (radioactive series of uranium, thorium, and 40K) and anthropogenic radionuclides (137Cs) in these wastes has been investigated by gamma spectrometry. Possible relationships between the radioactive content and the obtained chemical composition, determined by X-ray fluorescence, have also been studied by applying a principal component analysis (PCA). The results showed that the wastes with the highest radioactive content were sewage sludge with activity concentrations of 238U and 210Pb of 321 ± 38 Bq kg−1 and 110 ± 14 Bq kg−1, respectively. A correlation between radioactive content and Fe2O3 concentration was also observed. The annual effective dose rates to workers for the ashes estimated from the ash content ranged from 0.0033 mSv to 0.092 mSv and therefore do not pose a risk to workers as they are lower than the 1 mSv per year limit for the general public (DIRECTIVE 2013/59/EURATOM).

Water Quality Assessment Using the Water Quality Index, and Geographic Information Systems in Nador Canal, Morocco

In recent decades, water pollution has emerged as a significant concern, posing a threat to both humans and natural ecosystems. This study aimed to assess the spatial variations in water quality in the Nador Canal, Morocco using the water quality index combined with multivariate statistical techniques and geographic information systems (GIS). The parameters examined were then compared to the maximum permissible limit values recommended by Moroccan surface water standards and the World Health Organization. The results indicated that the WQI of Nador Canal is generally suitable for irrigation and unsuitable for drinking. It indicated that the quality of surface water in the Nador Canal is affected by organic pollutants, and this is evidenced by low levels of dissolved oxygen, the levels of elements were high, especially chlorine and sodium, in addition to a high concentration of ammonia, nitrate, and phosphate in some of the stations studied. Principal component analysis (PCA) results revealed that PC1–PC3 collectively accounted for 73% of the variation in surface water quality within the study area. The cluster analysis also proves that the water quality is relatively polluted. Potential contributing factors to surface water pollution include changes in the hydrological regime, household waste discharges, and agricultural activities. These findings furnish essential insights into water quality, particularly its suitability for irrigation, and contribute to enhancing the water quality management system of the Nador Canal in the Gharb region of Morocco.

Implementation of the International Classification of Diseases 11th revision behavioural indicators for disorders of intellectual development with co-occurring autism spectrum disorder.

The classification of mental, behavioural and neurodevelopmental disorders in the World Health Organization's International Classification of Diseases 11th revision (ICD-11) includes a comprehensive set of behavioural indicators (BIs) within the neurodevelopmental disorders grouping. BIs can be used to assess the severity of disorders of intellectual development in situations in which standardised measures of intellectual functioning and adaptive behaviours are not available or feasible. This international study examines the implementation characteristics of the BIs and compares them to standardised measures for assessing the severity of intellectual impairment and adaptive behaviours in disorders of intellectual development and autism spectrum disorder (ASD). The clinical utility of the ICD-11 and the fidelity of its application in international clinical settings were also assessed. A total of 116 children and adolescents (5-18years old) with a suspected or established diagnosis of disorders of intellectual development were included across four sites [Italy (n=18), Sri Lanka (n=19) and two sites in India (n=79)]. A principal component analysis was conducted to evaluate the application of the ICD-11 guidance for combining severity levels. Assessment using the BIs showed a higher proportion of individuals classified with mild severity, whereas the standardised measures indicated a higher proportion of severe ratings. Additionally, individuals with co-occurring ASD tended to have more severe impairments compared with those without ASD, as indicated by both BIs and standardised measures. Overall, the BIs were considered clinically useful, although more time and consideration were required when applying the guidelines for individuals with a co-occurring disorder of intellectual development and ASD. The principal component analysis revealed one principal component representing overall disorders of intellectual development severity levels. The ICD-11 BIs can be implemented as intended in international clinical settings for a broad range of presentations of individuals with neurodevelopmental disorders. Use of the BIs results in similar severity diagnoses to those made using standardised measures. The BIs are expected to improve the reliability of severity assessments in settings where appropriate standardised measures for intellectual and adaptive behaviours are not available or feasible.

Trends in Water Quality in a Tropical Kenyan River-estuary System: Responses to Anthropogenic Activities

Aims: To determine the spatial variation in physico-chemical water quality attributes in estuarine ecosystems of South Coast Kenya to inform its management. Study Design: We employed diagnostic research design where such factors as anthropogenic activities, hydrology, and accessibility were considered in choosing 12 sampling stations. A mixed sampling design (probability and non-probability) was used to sample. Place and Duration of Study: Four discharging rivers into estuarine system with a reference point were identified. 12 sampling points were earmarked and sampled for 12 months. Methodology: Nine selected water quality parameters were collected in triplicates monthly for 12 months. Temperature, dissolved oxygen, pH, conductivity, salinity and TDS were collected in situ using YSI Multiparameter meter (Professional plus) while nutrients were analyzed in the laboratory calorimetrically. Data was tested for normality and homogeneity of variances using Levene's and Shapiro-Wilk tests. Two-way analysis of variance (ANOVA), and Principal Component Analysis (PCA) were done using the 64-bit R Software version 4.3.0 to test for significant differences and correlate the parameters among the sampling sites respectively. Observed differences were considered statistically significant at P &lt; 0.05. Results: The measured environmental variables differed significantly among the sampling stations (P &lt; 0.05). temperature and salinity exhibited moderate to strong effect on water quality, while pH and nutrients (phosphates, nitrates, and ammonia) exhibited mixed effects with both negative and positive loadings on the Principal Components. It is demonstrated that the south coast estuary, Kenya is affected by two gradients: mineralization from the sea and the organic matter gradient at the upstream stations dominated by the fluvial inflows from the respective rivers. Conclusion: The south coast of Kenya estuary is impacted by natural processes and anthropogenic activities. we recommend for continued regular water quality assessment and monitoring to acquire sufficient data to shape policy frameworks towards its sustainable management.

Functional typology of settlements in the Srem region, Serbia

Abstract The development of the functional settlement typology methodology is of academic and practical importance as it incorporates the social, economic, and demographic dimensions of regional development. Rural settlements are seen as a base for labor; traditional urban centers have become a base for commuters, while at the same time, new economic centers are emerging where capital investment is accumulating. This article presents the research conducted in the Srem region (located in the province of Vojvodina) to determine the functional typology of the settlement, which is of social, economic, and demographic importance for the region itself and for Serbia as a whole. This well-known immigration area in Serbia has been inhabited for centuries for its specific economic and political reasons. The very intensive economic activities of the last two decades have been influenced by development investments and contributed to the functional transformation of the settlements. The census data from 2022 make it possible to determine a functional typology of settlements in the Srem region using the factor method (principal component analysis). The article aims to explain the basic characteristics of functional types of settlements and to determine the mechanisms of their territorial distribution, which would be helpful in the future planning and organization of local and regional development of the Republic of Serbia.

Profiling the Bioactive Compounds in Broccoli Heads with Varying Organ Sizes and Growing Seasons

Broccoli is a rich source of diverse bioactive compounds, but how their contents are influenced by different growing seasons and variations in broccoli head sizes remains elusive. To address this question, we quantified sixteen known bioactive compounds and seven minerals in broccoli with varying head sizes obtained in two different growing seasons. Our results suggest that the contents of vitamin C, total phenols, carotenoids, and glucoraphanin were significantly higher in samples from the summer–autumn season, showing increases of 157.46%, 34.74%, 51.80%, and 17.78%, respectively, compared with those from the winter–spring season. Moreover, chlorogenic acid is a phenolic compound with relatively high contents among the six detected, while beta-sitosterol is the sterol with relatively high contents. Further, principal component analysis was conducted to rank the comprehensive scores of the profiles of phenolic compounds, phytosterols, and minerals, demonstrating that the broccoli samples grown during the summer–autumn season achieved the highest composite scores. Our results indicate that broccoli heads from the summer–autumn season are richer in a combination of bioactive compounds and minerals than those from the winter–spring season based on the composite score. This study extends our understanding of the nutrition profiles in broccoli and also lays the foundation for breeding broccoli varieties with improved nutrition quality.

Nutrition addition alleviates negative drought effects on Quercus acutissima seedlings

Changing precipitation patterns have exacerbated severe drought events, causing tree die-off and forest mortality. Nutrition addition, as a critical method for forest management, may alleviate negative drought effects. Therefore, we set up a two-factor orthogonal experiment to study the responses of the leaf structural traits of Quercus acutissima to nutrition addition under drought stress. Leaf structural traits, including leaf morphological traits, leaf mass, and leaf nutrition traits, were measured under nine water and nutrition addition treatments. Two-way analysis of variance was used to detect the main effect and interaction of water and nutrition addition on leaf structural traits, principal component analysis was used to screen key traits. Our results show that drought had a unique and decisive effect on leaf length, leaf width, and leaf center, while leaf thickness only depended on nutrition addition. Conversely, no treatments changed the leaf length-width ratio and leaf nitrogen-phosphorus ratio. Besides, nutrition addition alleviated negative drought effects on leaf area, leaf saturated mass, leaf dry mass, leaf nitrogen content, leaf phosphorus content, leaf volume, specific leaf area, and leaf dry-matter content. According to the principal component 1 (54.83%), we screened seven key traits from leaf structural traits, including leaf area, leaf saturated mass, leaf dry mass, leaf nitrogen content, leaf volume, specific leaf area, and leaf dry-matter content, to effectively capture changes in leaf structural traits. Our results demonstrate that under drought stress, nutrition addition enhanced soil nutrition availability, increased leaf nitrogen and leaf phosphorus content, and finally alleviated negative drought effects. Thus, nutrition addition is crucial for plants to get through drought and for forest ecological restoration under global climate change.

Differentiation of Polygonatum Cyrtonema Hua from Different Geographical Origins by near-Infrared Spectroscopy with Chemometrics.

The identification of the geographical origin of Polygonatum cyrtonema Hua is of particular importance because the quality and market value of Polygonatum cyrtonema Hua from different production areas are highly variable due to differences in the growing environment and climatic conditions. This study utilized near-infrared spectra (NIR) of Polygonatum cyrtonema Hua (n = 400) to develop qualitative models for effective differentiation of Polygonatum cyrtonema Hua from various regions. The models were produced under different conditions to distinguish the origins distinctly. Ten pre-processing methods have been used to pre-process the original spectra (OS) and to select the most optimal spectral pre-processing method. Principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and orthogonal partial least squares discriminant analysis (OPLS-DA) were employed to determine appropriate models. For simplicity, the pretreated full spectrum was calculated by different wavelength selection methods, and the four most significant variables were selected as discriminant indicator variables. The results show that Polygonatum cyrtonema Hua from different regions can be effectively distinguished using spectra from a series of samples analyzed by OPLS-DA. The accuracy of the OPLS-DA model is also satisfactory, with a good differentiation rate. The study findings indicate the feasibility of using spectroscopy in combination with multivariate analysis to identify the geographical origins of Polygonatum cyrtonema Hua. The utilization of near-infrared spectroscopy combined with chemometrics exhibits high efficacy in discerning the provenance of herbal medicines and foods, thereby facilitating quality assurance measures.