Search Results (1,296)

Climatic force might sharpen the latitudinal gradients of foliar nutrients directly (the Temperature–Plant Physiological hypothesis) or indirectly (either through soil nutrient, the Soil Substrate Age hypothesis, or plant functional type (e.g., herbs and trees) composition, the Species Composition hypothesis). However, the validities, effectiveness, and key drivers of these hypotheses have not been further examined globally. Here, we tested these hypotheses by synthesizing data from 2344 observations of leaf N, leaf P, and leaf K in terrestrial plants. The results indicated that leaves enriched nutrients towards the polar region. The validity of each hypothesis was confirmed, with the exception of the Soil Substrate Age hypothesis failing to predict leaf N, as the climatic influence on leaf N occurs through a mechanism opposite to what the hypothesis suggests. Additionally, among all hypotheses, the Species Composition hypothesis was the most effective model for leaf N, whereas the Substrate Age hypothesis was the most effective model for leaf P and leaf K. Soil, climate, and plant functional type collectively accounted for over half of the variations in leaf nutrients. Specifically, soil nutrient was the strongest determinant for leaf P and K, whereas plant functional type for leaf N. Taking into account changes in plant functional types and soil nutrients will improve the modeling of biogeochemical cycles under climate change. We expect further verification by global investigations of leaf stoichiometry using uniform methods. Full article

This study aimed to determine the impact of economic policy uncertainty and geopolitical risk on environmental quality in 17 selected countries. In addition, it also aimed to test the environmental Kuznets curve hypothesis (EKC) within the scope of the determined variables and model. In this context, analyses were carried out with annual data for the period 1997–2022, based on the country group for which the economic policy uncertainty index was calculated, subject to data limitations. In this study, a Quantile Regression of Panel Data (QRPD) analysis, OLS (Ordinary Least Squares), and a panel causality test were used. As a result of the estimation with the Quantile Regression of Panel Data (QRPD), it was found that the increase in economic policy uncertainty had a positive effect on environmental quality in most of the quantiles, while geopolitical risk had significant and negative effects on environmental quality in the medium and high quantiles. The validity of the EKC hypothesis was also proved in the analysis. According to the results of the panel causality test, there was a bidirectional causality relationship between environmental quality and all the independent variables, except the square of economic growth. In order to make a comparison with the new-generation estimation method, QRPD, it was observed that the estimation results with the classical regression method, OLS, were similar. In light of these findings, it is recommended that policy makers pursue strategies that balance economic growth and environmental quality, reduce the environmental impacts of geopolitical risks, and favor a renewable energy transition. Moreover, long-term and stable environmental policies have a crucial role in the success of these strategies. Full article

Critical listening, critical reading, and critical thinking are three closely related cognitive skills that aim to evaluate information with an analytical and questioning approach. Critical listening and critical reading, which are receptive language skills, represent the application of critical thinking in different contexts. Critical thinking, which is a productive language skill, provides a framework for these two receptive language skills and enables the evaluation of the accuracy of information accessed through critical listening and critical reading, analyzing different perspectives and making inferences to reach correct conclusions. These two skills support the development of critical thinking skills and contribute to individuals gaining deeper understanding based on the perspective of knowledge. This study aims to determine the relationships between critical listening, critical reading, and critical thinking, the effects of these variables on each other, and the explanation ratios. The study group of this study was determined through simple random sampling, one of the random sampling methods. The participants consisted of 201 teacher candidates studying in the Department of Turkish Language Teaching at a university in the north of Türkiye. The Critical Listening Scale, Critical Thinking Attitude Scale, Critical Reading Self-Efficacy Perception Scale, and a personal information form were used to collect research data. The data collected in the research were analyzed using structural equation modeling via AMOS 22.0. As a result of the research, it was determined that all hypothesis models established based on the relevant literature were valid. Two of the three hypotheses regarding the theoretical model were supported by the data, and one hypothesis was rejected. Critical listening has a direct high level effect on critical thinking and predicts it at a significant level. Critical listening has a direct high-level effect on critical reading and predicts it at a significant level, while explaining 65% of the total variance related to critical reading. The effect of critical reading on critical thinking is insignificant and does not predict critical thinking at a significant level. In the theoretical model created the effect of critical reading on critical thinking is insignificant, but these two variables explain 85% of the variance related to critical thinking. As a result of the research, it can be said that the main predictor of critical thinking is critical listening, and that critical reading and critical thinking develop depending on the development of critical listening. Full article

Most commercial citrus fruits are grown in acidic soils with high copper (Cu) and low organic matter levels in China. Sweet orange (Citrus sinensis (L.) Osbeck cv. Xuegan) seedlings were treated with 0 (HA0), 0.1 (HA0.1), or 0.5 (HA0.5) mM humic acid (HA) and 0.5 (Cu0.5) or 400 (Cu400 or Cu excess) μM CuCl₂ for 24 weeks. The purpose was to validate the hypothesis that HA reduces the oxidative injury caused by Cu400 in roots and leaves via the coordination of strengthened antioxidant defense and glyoxalase systems. Copper excess increased the superoxide anion production rate by 27.0% and 14.2% in leaves and by 47.9% and 33.9% in roots, the malonaldehyde concentration by 199.6% and 27.8% in leaves and by 369.4% and 77.4% in roots, and the methylglyoxal concentration by 18.2% and 6.6% in leaves and by 381.8% and 153.3% in roots, as well as the H₂O₂ production rate (HPR) by 70.5% and 16.5% in roots, respectively, at HA0 and HA0.5. Also, Cu400 increased the leaf HPR at HA0, but not at HA0.5. The addition of HA reduced the Cu400-induced production and accumulation of reactive oxygen species and methylglyoxal and alleviated the impairment of Cu400 to the antioxidant defense system (ascorbate-glutathione cycle, antioxidant enzymes, sulfur-containing compounds, and sulfur-metabolizing enzymes) and glyoxalase system in roots and leaves. The HA-mediated amelioration of Cu toxicity involved reduced oxidative injury due to the coordination of strengthened antioxidant defense and glyoxalase systems. These findings highlight the promise of HA for sustainable citrus cultivation in heavy metal (Cu)-polluted soils. Full article

This study investigates the impact of professional competencies (moral, knowledge, and skill) on the occupational identity of government-supported preschool teacher trainees and examines the moderating role of support from significant others, including family, peers, and mentors. A quantitative research methodology was employed, involving a cross-sectional survey of 193 publicly funded teacher trainees. Validated scales were used to measure professional competencies, occupational identity, and perceived support. The results revealed a strong positive correlation between professional competencies and occupational identity (r = 0.61, p < 0.01), supporting the hypothesis that higher competency levels enhance trainees’ professional identity. Furthermore, support from significant others moderated this relationship, with a higher level of support amplifying the positive association (β = 1.412, p < 0.01). These findings highlight the interconnected nature of professional competencies and social support in shaping occupational identity. Based on these results, it is recommended that teacher training programs integrate targeted competency-building strategies alongside structured support systems to enhance professional identity formation. These initiatives are critical for fostering sustainable professional development and improving the quality and stability of preschool education. Full article

Total leaf area per shoot (A_T) can reflect the photosynthetic capacity of a shoot. A prior study hypothesized that A_T is proportional to the product of the sum of the individual leaf widths per shoot (L_KS) and the maximum individual leaf length per shoot (W_KS), referred to as the Montgomery–Koyama–Smith equation (MKSE). However, empirical evidence does not support such a proportional relationship hypothesis, as A_T was found to allometrically scale with L_KSW_KS, i.e., $A_{\mathrm{T}}\propto {\left(L_{\mathrm{K}\mathrm{S}}{W}_{\mathrm{K}\mathrm{S}}\right)}^{\mathsf{\alpha }}$, where $\mathsf{\alpha }\ne 1$, referred to as the power law equation (PLE). Given that there is variation in the total number of leaves per shoot (n), little is known about whether the leaf area distribution has an explicit mathematical link with the sorted leaf area sequence per shoot, and it is unknown whether the mathematical link can affect the prediction accuracy of the MKSE and PLE. In the present study, the leaves of 500 shoots of a dwarf bamboo (Sasaella kongosanensis ‘Aureostriatus’) were scanned, and the leaf area, length, and width values were obtained by digitizing the leaf images. We selected the shoots with n ranging from 3 to 10, which accounted for 76.6% of the totally sampled shoots (388 out of 500 shoots). We used the formula for the sum of the first j terms (j ranging from 1 to n) of a geometric series (GS), with the mean of the quotients of any adjacent two terms (denoted as ${\overline{q}}_A$) per shoot as the common ratio of the GS, to fit the cumulative leaf area observations. Mean absolute percentage error (MAPE) was used to measure the goodness of fit of the GS. We found that there were 367 out of 388 shoots (94.6%) where 1 < ${\overline{q}}_A$ < 1.618 and MAPE < 15%, and these 367 shoots were defined as valid samples. The GS hypothesis for leaf area distribution was supported by the result that the MAPE values for most valid samples (349 out of 367, i.e., 95.1%) were smaller than 5%. Here, we provide a theoretical basis using the GS hypothesis to demonstrate the validity of the MKSE and PLE. The MAPE values for the two equations to predict A_T were smaller than 5%. This work demonstrates that the leaf area sequence per shoot follows a GS and provides a useful tool for the calculation of total leaf area per shoot, which is helpful to assess the photosynthetic capacity of plants. Full article

The accuracy and stability of Very Long Baseline Interferometry (VLBI) systems are essential for maintaining global geodetic reference frames such as the International Terrestrial Reference Frame (ITRF). This study focuses on the precise determination of the VLBI Invariant Point (IVP) and the detection of antenna axis offset. Ground-based surveys were conducted at the Sejong Space Geodetic Observatory using high-precision instruments, including total station, to measure slant distances, as well as horizontal and vertical angles from fixed pillars to reflectors attached to the VLBI instrument. The reflectors comprised both prisms and reflective sheets to enhance redundancy and data reliability. A detailed stochastic model incorporating variance component estimation was employed to manage the varying precision of the observations. The analysis revealed significant measurement variability, particularly in slant distance measurements involving prisms. Iterative refinement of the variance components improved the reliability of the IVP and antenna axis offset estimates. The study identified an antenna axis offset of 5.6 mm, which was statistically validated through hypothesis testing, confirming its significance at a 0.01 significance level. This is a significance level corresponding to approximately a 2.576 sigma threshold, which represents a 99% confidence level. This study highlights the importance of accurate stochastic modeling in ensuring the precision and reliability of the estimated VLBI IVP and antenna axis offset. Additionally, the results can serve as a priori information for VLBI data analysis. Full article

Despite significant progress in recent decades, air pollution remains the leading environmental cause of premature death in Europe. Urban populations are particularly exposed to high concentrations of air pollutants, such as particulate matter smaller than 10 µm (PM₁₀). Understanding the spatiotemporal variations of PM₁₀ is essential for developing effective control strategies. This study aimed to enhance PM₁₀ prediction models by integrating landscape metrics as ecological indicators into our previous models, assessing their significance in monthly average PM₁₀ concentrations, and analyzing their correlations with PM₁₀ air pollution across European urban landscapes during heating (cold) and non-heating (warm) seasons. In our previous research, we only calculated the proportion of land uses (PLANDs), but according to our current research hypothesis, landscape metrics have a significant impact on PM₁₀ air quality. Therefore, we expanded our independent variables by incorporating landscape metrics that capture compositional heterogeneity, including the Shannon diversity index (SHDI), as well as metrics that reflect configurational heterogeneity in urban landscapes, such as the Mean Patch Area (MPA) and Shape Index (SHI). Considering data from 1216 European air quality (AQ) stations, we applied the Random Forest model using cross-validation to discover patterns and complex relationships. Climatological factors, such as monthly average temperature, wind speed, precipitation, and mean sea level air pressure, emerged as key predictors, particularly during the heating season when the impact of temperature on PM₁₀ prediction increased from 5.80% to 22.46% at 3 km. Landscape metrics, including the SHDI, MPA, and SHI, were significantly related to the monthly average PM₁₀ concentration. The SHDI was negatively correlated with PM₁₀ levels, suggesting that heterogeneous landscapes could help mitigate pollution. Our enhanced model achieved an R² of 0.58 in the 1000 m buffer zone and 0.66 in the 3000 m buffer zone, underscoring the utility of these variables in improving PM₁₀ predictions. Our findings suggest that increased urban landscape complexity, smaller patch sizes, and more fragmented land uses associated with PM₁₀ sources such as built-up areas, along with larger and more evenly distributed green spaces, can contribute to the control and reduction of PM₁₀ pollution. Full article

Background: Effective management of primary apical periodontitis depends on understanding the dynamic interactions within the root canal microbiome. This study aimed to investigate the effect of sequential antimicrobial phases on the root canal microbiome during a two-visit treatment approach, with a focus on calcium hydroxide medication. Methods: Samples were collected from three teeth across four treatment phases: initial infection (S1), after chemomechanical preparation (S2), after intracanal medication (S3), and after a final flush (S4). DNA was extracted, and the V3–V4 regions of the 16S rRNA gene were sequenced using Illumina MiSeq. Sequencing data were analyzed with QIIME 2, and differentially abundant taxa were identified using linear discriminant analysis effect size (LEfSe). Results: While microbial community composition did not differ significantly between phases, the Firmicutes/Bacteroidetes ratio decreased after the antimicrobial stages. LEfSe analysis revealed higher abundances of Lactobacillales, Arthrobacter, and Veillonella in the untreated (CMP) group. Bifidobacterium longum was relatively more abundant in the intracanal medication (ICM) phase, and Dorea formicigenerans was more abundant in the final-flush (FF) phase. Conclusions: Although calcium hydroxide treatment did not induce statistically significant changes in overall root canal microbial composition, trends such as a reduction in the Firmicutes/Bacteroidetes ratio and a relative increase in Bifidobacterium longum numbers suggest potential ecological shifts. The observed relative increase in Bifidobacterium longum numbers may represent a hypothesis-driven observation reflecting indirect ecological effects rather than direct pH modulation. While visual patterns (e.g., PCA clustering) were observed, they lacked statistical support. Further studies with larger sample sizes are needed to validate these observations and assess the potential role of beneficial bacteria in root canal treatments. Full article

The hospitality industry, well-known for its energetic and people-intensive nature, frequently depends on effective leadership to motivate teamwork and safeguard sustainable operational success. Nevertheless, leadership approaches may significantly influence workplace dynamics and leader narcissism appears to be a probable disruptor. This study explores the dual-edged influence of leader narcissism in the hospitality industry, specifically in determining employee unheard voice behavior and bullying in the workplace. While leader narcissism can amplify unheard voices by nurturing an environment where staff feel forced to speak up, it can also fuel workplace conflict by generating toxic interactions and advancing bullying in the workplace. This research utilized a self-administrated questionnaire, collecting data from employees in five-star hotels and category (A) tourism companies in Cairo, Egypt, from May to August 2024 through a convenience sampling technique. Of the 425 distributed questionnaires, 394 valid responses were received, and Smart PLS-3.0 was employed for hypothesis testing. The study’s findings indicate that employee voice behavior positively influences workplace bullying. There exists a favorable correlation between employee voice behavior and leader narcissism. Moreover, leader narcissism is proven to have a positive relationship with workplace bullying. Leader narcissism was recognized as a mediating variable in the connection between employee voice behavior and workplace bullying. While previous research has investigated how these factors influence work-related outcomes in broader organizational settings, this study focuses on their implications in tourism and hospitality. Additionally, the study delves into how leader narcissism mediates the connection between employee voice behavior and workplace bullying in the tourism industry. By highlighting and exploring the complexities of leader narcissism and its influence on workplace interrelationships, this research paper may offer valuable insights for top managers, policymakers, and academics seeking to generate healthier and more productive workplace environments in the tourism industry. Full article

Background/Objectives: Cognitive deficits and negative symptoms associated with schizophrenia are poorly managed by current antipsychotics. In order to develop effective treatments, refining animal models of neurodevelopmental disorders is essential. Methods: To address their multifactorial etiology, we developed a new three-hit mouse model based on the hypoglutamatergic hypothesis of the pathology combined with early stress, offering strong construct validity. Thus, a genetic susceptibility (serine racemase deletion) was associated with an early environmental stress (24 h maternal separation at 9 days of age) and a further pharmacological treatment with phencyclidine (PCP, a glutamate receptor antagonist treatment, 10 mg/kg/day, from 8 to 10 weeks of age). The face validity of this model was assessed in female mice 1 and 6 weeks after the end of PCP treatment by a set of behavioral experiments investigating positive- and negative-like symptoms and cognitive deficits. Results: Our results showed that the three-hit mice displayed persistent hyperlocomotion (positive-like symptoms) and social behavior impairment deficits (negative-like symptoms) but non-persistent spatial working memory deficits (cognitive symptoms). Conclusions: Our work confirms the usefulness of a three-hit combination to model, particularly for negative-like symptoms associated with schizophrenia and other psychiatric disorders. The model therefore gathers powerful construct and face validities and supports an involvement of glutamate dysfunction in behavioral symptoms. Full article

The neonatal period is a critical phase for the development of the intestinal immune system, marked by rapid adaptation to the external environment and unique nutritional demands. Breast milk plays a pivotal role in this transition, yet the mechanisms by which it influences neonatal mucosal immunity remain unclear. This review examines the potential mechanisms by which cell-free DNA (cfDNA) in breast milk may impact neonatal immune development, particularly through Toll-like receptor 9 (TLR9) signalling and gut microbiota interactions. We propose that cfDNA in breast milk interacts with TLR9 on the apical surface of neonatal intestinal epithelial cells, potentially serving as an initial anti-inflammatory stimulus before the establishment of commensal bacteria. This hypothesis is supported by the high concentration and stability of cfDNA in breast milk, as well as the known activation of TLR9 by mitochondrial DNA in breast milk. The review emphasises the need for further empirical research to validate these interactions and their implications for neonatal health, suggesting that understanding these dynamics could lead to improved strategies for neonatal care and disease prevention. Full article

Finding an effective treatment for T-PLL patients remains a significant challenge. Alemtuzumab, currently the gold standard, is insufficient in managing the aggressiveness of the disease in the long term. Consequently, numerous efforts are underway to address this unmet clinical need. The rarity of the disease limits the ability to conduct robust clinical trials, making in silico, ex vivo, and in vivo drug screenings essential for designing new therapeutic strategies for T-PLL. We conducted a drug repurposing analysis based on T-PLL gene expression data and identified proteasome inhibitors (PIs) as a promising new class of compounds capable of reversing the T-PLL phenotype. Treatment of ex vivo T-PLL cells with Bortezomib and Carfilzomib, two PI compounds, supported this hypothesis by demonstrating increased apoptosis in leukemic cells. The current lack of a suitable in vitro model for the study of T-PLL prompted us to perform similar experiments in the SUP-T11 cell line, validating its potential by showing an increased apoptotic rate. Taken together, these findings open new avenues for investigating the molecular mechanisms underlying the efficacy of PI in T-PLL and expand the spectrum of potential therapeutic strategies for this highly aggressive disease. Full article

Background: Endometrial cancer is strongly associated with obesity, and tumors often harbor mutations in major cancer signaling pathways. To inform the integration of body composition into targeted therapy paradigms, this hypothesis-generating study explores the association between muscle mass, body fat, and tumor proteomics. Methods: We analyzed data from 113 patients in The Cancer Genome Atlas (TCGA) and Cancer Proteomic Tumor Analysis Consortium (CPTAC) cohorts and their corresponding abdominal CT scans. Among these patients, tumor proteomics data were available for 45 patients, and 133 proteins were analyzed. Adiposity and muscle components were assessed at the L3 vertebral level on the CT scans. Patients were stratified into tertiles of muscle and fat mass and categorized into three groups: high muscle/low adiposity, high muscle/high adiposity, and low muscle/all adiposities. Linear and Cox regression models were adjusted for study cohort, stage, histology type, age, race, and ethnicity. Results: Compared with the high-muscle/low-adiposity group, both the high-muscle/high-adiposity (HR = 4.3, 95% CI = 1.0–29.0) and low-muscle (HR = 4.4, 95% CI = 1.3–14.9) groups experienced higher mortality. Low muscle was associated with higher expression of phospho-4EBP1(T37 and S65), phospho-GYS(S641) and phospho-MAPK(T202/Y204) but lower expression of ARID1A, CHK2, SYK, LCK, EEF2, CYCLIN B1, and FOXO3A. High muscle/high adiposity was associated with higher expression of phospho-4EBP1 (T37), phospho-GYS (S641), CHK1, PEA15, SMAD3, BAX, DJ1, GYS, PKM2, COMPLEX II Subunit 30, and phospho-P70S6K (T389) but with lower expression of CHK2, CRAF, MSH6, TUBERIN, PR, ERK2, beta-CATENIN, AKT, and S6. Conclusions: These findings demonstrate an association between body composition and proteins involved in key cancer signaling pathways, notably the PI3K/AKT/MTOR, MAPK/ERK, cell cycle regulation, DNA damage response, and mismatch repair pathways. These findings warrant further validation and assessment in relation to prognosis and outcomes in these patients. Full article

In the initial investigations of hazard assessment for the Cortinas sector at a 1:25,000 scale, researchers validated the hypothesis that the terrain must be under specific magnitudes of conditioning factors for an instability event to occur, which does not depend only on certain critical thresholds of rainfall and earthquakes. This process was termed accumulated geotechnical deterioration (AGD). A larger-scale analysis of geotechnical criteria was conducted based on data obtained from direct exploration and geophysics, examining conditions prior to slope failure, immediately after failure, and several years later. The results showed that, indeed, the terrain experienced an increase in deterioration that, under the influence of a critical rainfall event, led to failure; however, the stability of the terrain later recovered to the point that failure did not occur under similar rainfall events. In accordance with this, a novel method of analysis is established herein at a 1:5000 scale, which uses AGD to predict instability events by calculating the safety factor derived from the application of the infinite slope formula in a GIS framework. By incorporating specific variables and field measurements, a better approximation for the prediction of an instability event can be achieved. This study identifies the innovative factors of this method and provides a baseline for future research. Full article