Significant Quadratic Relationship Research Articles

Poly-β-hydroxybutyrate supplementation enhanced the growth and immune responses of juvenile Nile tilapia (Oreochromis niloticus)

Development of alternative disease treatment and prevention strategies has received considerable attention in recent years due to frequent epizootic outbreaks in modern intensive aquaculture. Poly-β-hydroxybutyrate (PHB) is a biopolymer synthesized by some bacteria with potential immunostimulatory effects. This study analyzed the potential of PHB as an immunomodulator in juvenile Nile tilapia utilizing in vitro and in vivo approaches. Head-kidney-derived macrophage production of intra- and extra-cellular superoxide anion exhibited significant linear and quadratic relationships with graded doses (0.0, 0.5, 1.0, 2.0, 4.0 and 8.0 mM) of a PHB precursor, 3-hydroxybutryate (3HB). Additionally, lyophilized PHB-synthesizing bacteria, Zobellella denitrificans (ZD1), were supplemented to a practical basal diet for Nile tilapia (36% crude protein and 6% crude lipid) to produce five isonitrogenous and isolipidic experimental diets containing PHB in five stepwise increments (0.125, 0.25, 0.5, 1.0, and 2.0% of dry-diet weight). After termination of the feeding trial, Nile tilapia exhibited dose-dependent linear and quadratic relationships in percentage weight gain, as well as feed efficiency, protein conversion efficiency, and hepatosomatic index. Finally, PHB-supplemented diets did significantly modulate intestinal microbiota composition. In conclusion, Nile tilapia exhibited enhanced growth parameters, condition factors, immunological responses, and intestinal microbiota modulation when fed PHB, with the optimal inclusion level determined to be 1% of dry diet.

The Effects of Price Context and Prior Product Knowledge on Consumers’ Product Evaluations

This research examines how consumers rely on price and prior product knowledge in product quality evaluations. To understand the interaction effects of price context and prior product knowledge on quality evaluations, a conceptual framework based on cue utilization theory and information processing theory was developed. It is proposed that low knowledgeable consumers are more likely to use price as a quality indicator in a low-priced context; moderate knowledgeable consumers tend to rely on their knowledge to make product evaluations; high knowledgeable consumers are more likely to use their product knowledge in a high-priced context. Experimental studies were conducted using student subjects to test the proposed hypotheses. Results of the experiments showed significant interaction effects between price context and prior knowledge on quality evaluations. A significant quadratic relationship between the use of price and the level of prior product knowledge was observed only in a low-priced context, providing support for the proposed hypotheses in the conceptual model.

Evaluation of potential increase in photosynthetic efficiency of cassava (Manihot esculenta Crantz) plants exposed to elevated carbon dioxide.

Cassava (Manihot esculenta Crantz), an important tropical crop, is affected by extreme climatic events, including rising CO2 levels. We evaluated the short-term effect of elevated CO2 concentration (ECO2 ) (600, 800 and 1000ppm) on the photosynthetic efficiency of 14 cassava genotypes. ECO2 significantly altered gaseous exchange parameters (net photosynthetic rate (P n ), stomatal conductance (g s ), intercellular CO2 (C i ) and transpiration (E )) in cassava leaves. There were significant but varying interactive effects between ECO2 and varieties on these physiological characteristics. ECO2 at 600 and 800ppm increased the P n rate in the range of 13-24% in comparison to 400ppm (ambient CO2 ), followed by acclimation at the highest concentration of 1000ppm. A similar trend was observed in g s and E . Conversely, C i increased significantly and linearly across increasing CO2 concentration. Along with C i , a steady increase in water use efficiency [WUEintrinsic (P n /g s ) and WUEinstantaneous (P n /E )] across various CO2 concentrations corresponded with the central role of restricted stomatal activity, a common response under ECO2 . Furthermore, P n had a significant quadratic relationship with the ECO2 (R 2 =0.489) and a significant and linear relationship with C i (R 2 =0.227). Relative humidity and vapour pressure deficit during the time of measurements remained at 70-85% and ~0.9-1.31kPa, respectively, at 26±2°C leaf temperature. Notably, not a single variety exhibited constant performance for any of the parameters across CO2 concentrations. Our results indicate that the potential photosynthesis can be increased up to 800ppm cassava varieties with high sink capacity can be cultivated under protected cultivation to attain higher productivity.

The relationship between cerebral asymmetry and measures of psychopathy in a non-clinical sample is moderated by both empathic challenge and biological sex

This study investigated the relationship between psychopathy, as assessed by the Levenson Self-Report Psychopathy (LSRP) scale, and cerebral laterality. EEG recordings from frontal cortex (L3 and L4) were taken during both resting conditions and while viewing a video of an emergency field amputation, used as an empathic challenge. The ratio of alpha power from the two recording site was taken as an index of relative activity in the two hemispheres. Eighty three students from the University subject pool were recruited as participants. Male participants had a significantly higher mean LSRP score than did female participants. While LSRP scores were unrelated to cerebral laterality under resting conditions, there was both a significant linear and quadratic negative relationship between LSRP scores and relative left-hemisphere alpha activity. As alpha activity has been reported to be inversely related to brain or mental activity, a negative relationship can be inferred between LSRP scores and right hemisphere neural activity. The female participants had a much stronger quadratic relationship than did the combined sample, while the male sample showed only weak, non-significant relationships. Our data suggest that the relationship between psychopathy and cerebral laterality may be sexually dimorphic.

A nested grouped random parameter negative binomial model for modeling segment-level crash counts

In this study, a nested grouped random parameter negative binomial framework is proposed to model crash counts at the segment level, a three-level longitudinal framework. The proposed model accounts for correlations along county routes and over time and thus includes a time variable, the year index, to analyze crash counts. The model is applied to crashes on undivided two-lane arterial roads in Ohio from 2012 to 2017. The results present two variants of the model: one with varying intercepts and fixed slopes and the other with varying intercepts and slopes. Both variants have comparable interpretations concerning the fixed parameters, but the latter variant exhibits a significantly improved fit and provides additional information on the interpretations. The results show a significant quadratic relationship between the time variable and the crash count, indicating that, on average, the crash count of segments increases with a decreasing rate as time variable increases. Regarding random parameters, the findings show that 17% of segments within routes and 2% of routes exhibit crash counts that decrease at accelerating downward trend as time variable increases. The effect of the natural logarithm of the segment length varies significantly across different routes, with an increase in this value primarily leading to an increase in crashes. On the other hand, the effect of the total shoulder width also varies across routes, but unlike the former, an increase in this value generally results in a decrease in crashes. The proposed model shows high forecast accuracy for crash count prediction, making it a valuable tool for informed decision-making in safety improvement.

Linking temperature sensitivity of mangrove communities, populations and individuals across a tropical‐temperate transitional zone

Abstract Climate change is reshaping coastal wetlands worldwide, driving ecosystem shifts like mangrove poleward expansion into saltmarshes in tropical‐temperate transitional zones. Though warming is recognized as the primary driver, a lack of detailed field studies limits our ability to predict mangrove responses to rapid climate warming. Here, we characterized how mangroves vary across a temperature gradient at 18 sites along Florida's Gulf of Mexico coast (USA). We used minimum air temperature (Tmin) derived from daily data from 1989 to 2021 as the independent variable and applied plot‐based and synoptic approaches to quantify species‐specific mangrove variation at community, population, and individual levels. We then used these results to spatially project future mangrove ecosystem properties under multiple warming scenarios. Across the Tmin gradient from −10.8 to −1.4°C, mangrove canopy height and coverage ranged from 0.4 to 11.5 m and 15% to 98%, respectively, with both exhibiting sigmoidal increases with Tmin. Estimated mangrove aboveground biomass ranged from 0 to 496.7 Mg/ha and showed a positive linear relationship with Tmin due both to the tall tree stratum's increased biomass per tree and higher abundance. While the population abundance and coverage of Rhizophora mangle and Laguncularia racemosa had positive linear relationships with Tmin, Avicennia germinans exhibited a significant quadratic relationship, reflecting the higher freeze tolerance of this species. Such tolerance may stem from A. germinans' higher morphological plasticity observed at the individual level, adapting to cold stress by exhibiting a more shrub‐like architecture at colder sites. Based on these field‐derived quantitative relationships, we projected substantial increases in mangrove coverage and canopy height near current range limits, with tall A. germinans dominating in the north and R. mangle dominating the centre and south of the study region. Synthesis. To better predict the ecological consequences in coastal wetlands under future climate change, it is essential to understand how mangroves respond to winter temperature regimes across a temperature gradient. Collectively, these cross‐level and species‐specific results advance our understanding of mangrove temperature sensitivity and provide information about the future of coastal wetland structure and function in response to a changing climate.

A sex-specific pathway linking early life maltreatment, vagal activity, and depressive symptoms

ABSTRACT Background: Experiences of early life maltreatment (ELM) are alarmingly common and represent a risk factor for the development of psychopathology, particularly depression. Research has focused on alterations in autonomic nervous system (ANS) functioning as a mediator of negative mental health outcomes associated with ELM. Early alterations in autonomic vagal activity (vmHRV) may moderate the relationship between ELM and depression, particularly when considering forms of emotional maltreatment. Recent evidence suggests that the relationships of both ELM and vmHRV with depression may be non-linear, particularly considering females. Objective: Building on and extending theoretical considerations and previous work, the present work aims to further the current understanding of the complex relationships between ELM exposure, vmHRV, and depression. Methods: This study uses an adaptive modelling approach, combining exploratory network-based analyses with linear and quadratic moderation analyses, drawing on a large sample of males and females across adolescence (total N = 213; outpatient at-risk sample and healthy controls) and adulthood (total N = 85; community-based convenience sample). Results: Exploratory network-based analyses reveal that exposure to emotional abuse is particularly central within a network of ELM subtypes, depressive symptoms, and concurrent vmHRV in both adolescents and adults. In adults, emotional neglect shows strong associations with both emotional abuse and vmHRV and is highly central as a network node, which is not observed in adolescents. Moderator analyses reveal significant interactions between emotional maltreatment and vmHRV predicting depressive symptoms in adult females. Significant quadratic relationships of emotional maltreatment and vmHRV with depression are observed in both adolescent and adult females. Conclusions: The present findings contribute to the understanding of the psychological and physiological mechanisms by which ELM acts as a risk factor for the development of depression. Ultimately, this will contribute to the development of targeted and effective intervention strategies to mitigate the detrimental effects of early adversity.

Phylogeography and phenotypic wing shape variation in a damselfly across populations in Europe.

Describing geographical variation in morphology of organisms in combination with data on genetic differentiation and biogeography can provide important information on how natural selection shapes such variation. Here we study genetic structure using ddRAD seq and wing shape variation using geometric morphometrics in 14 populations of the damselfly Lestes sponsa along its latitudinal range in Europe. The genetic analysis showed a significant, yet relatively weak population structure with high genetic heterozygosity and low inbreeding coefficients, indicating that neutral processes contributed very little to the observed wing shape differences. The genetic analysis also showed that some regions of the genome (about 10%) are putatively shaped by selection. The phylogenetic analysis showed that the Spanish and French populations were the ancestral ones with northern Swedish and Finnish populations being the most derived ones. We found that wing shape differed significantly among populations and showed a significant quadratic (but weak) relationship with latitude. This latitudinal relationship was largely attributed to allometric effects of wing size, but non-allometric variation also explained a portion of this relationship. However, wing shape showed no phylogenetic signal suggesting that lineage-specific variation did not contribute to the variation along the latitudinal gradient. In contrast, wing size, which is correlated with body size in L. sponsa, had a strong negative correlation with latitude. Our results suggest a relatively weak population structure among the sampled populations across Europe, but a clear differentiation between south and north populations. The observed geographic phenotypic variation in wing shape may have been affected by different local selection pressures or environmental effects.

Mechanical properties of uniaxial compression of total tailings paste under lateral restraint effect

After the filling of paste into the mined-out area, significant disparities are evident between the mechanical characteristics and the unconfined conditions, primarily caused by the lateral extrusion of the surrounding rock. To research the mechanical properties of paste under the influence of lateral restraint effect, a device was developed to apply lateral pressure to the paste. This was then combined with an existing uniaxial press machine to carry out uniaxial compression testing of the paste subject to lateral restraint effect. The device was used to carry out uniaxial compression tests under different curing ages and dry and wet conditions under the lateral restraint effect, and compared with the unconfined condition. The study revealed a considerable increase in the paste's strength caused by the lateral restraint effect, resulting in a growth rate ranging from 12.35% to 64.51%. The mathematical model of lateral stress and strength was established, and it was found that the two showed a significant quadratic function relationship. By acquiring the stress-strain data of the loading process, the evolution characteristics of the stress-strain curve of the paste under the influence of the lateral restraint effect are revealed, and the change rule of the elastic modulus is explored. Under the influence of the lateral restraint effect, the growth rate reaches 1.93% to 64.04%. When comparing the crack propagation characteristics of the paste with and without the influence of the lateral restraint effect, it was observed that the failure mode of the paste under uniaxial compression shifts from tensile failure to shear failure. Finally, this paper proposes the strength design method for backfill with considerations to the lateral restraint effect. The reliability of the suggested method is established through actual sampling results in the mine. The research findings hold significant guiding value for the secure and efficient extraction of paste backfill mines.

Restorative justice and dynamic chronologies in disciplinary referrals in an urban middle school

ABSTRACT School referrals are a key initial step in the school-to-prison pipeline, both via direct referral to law enforcement and through accumulated mechanism of control upon students. However, few studies have examined the chronological trajectory of referral usage within a school year. This study investigated whether the assignment of school disciplinary referrals varies over time over a typical school year, and whether that variation differed based on student demographic characteristics. Using longitudinal data from a medium-sized urban middle school in the eastern United States, the study found a statistically significant quadratic relationship between office referrals and time among students of color specifically. However, no such relationship could be observed for White students, for whom referrals were subject to little variation over the course of a school year. Finally, evidence was found that racial disparities in referrals were also subject to a quadratic trajectory as the year progressed. These findings demonstrate the need for deeper investigation into racialized variation in how office referrals are administered over time.

The use of small emitter flow rate in drip irrigation favored methane uptake in arid potato fields

Drip irrigation has been widely used in agriculture, while the mechanism underlying the effect of drip irrigation system design and management on soil methane (CH4) uptake have not been fully studied. A two-year experiment was conducted to explore the effects of different emitter flow rates of drip irrigation (1.3, 2.0, and 3.0 L/h) on CH4 uptake in potato fields in an arid region of Northwest China. Results showed that compared to emitter flow rates of 2.0 and 3.0 L/h, the 1.3 L/h flow rate significantly increased the cumulative CH4 uptake by 6.3–16.2%, mainly due to the increase in the abundance of the pmoA gene by 15.2–49.5%, and by the decrease of water-filled pore space (WFPS), increasing the effective CH4 diffusion coefficient (Dp) and soil oxygen concentration in the topsoil. A hump-shaped relationship was found between WFPS and CH4 uptake flux, and the optimum WFPS for CH4 uptake was about 44.8%. The treatment with an emitter flow rate of 1.3 L/h exhibited the highest frequency (28.6%) of favorable WFPS for CH4 uptake, compared to the 2.0 and 3.0 L/h treatments. In addition, significant negative quadratic relationships were observed between both Dp and soil oxygen with CH4 uptake, and optimal values were 0.02 cm2 s−1 and 18.7%, respectively. There was no significant difference in CH4 uptake between 2.0 and 3.0 L/h treatments in 2021 and 2022, due to high WFPS and low oxygen concentrations in both treatments. Multiple linear regressions indicated that soil oxygen concentration became a major limiting factor under emitter flow rates of 2.0 and 3.0 L/h. This study provides insights into mechanisms of soil CH4 uptake in drip-irrigated farmland, which gives guidance on developing irrigation strategies for sustainable production and CH4 mitigation in irrigated arid land.

Effects of water and nitrogen rate on grain-filling characteristics under high-low seedbed cultivation in winter wheat

A high-efficiency mode of high-low seedbed cultivation (HLSC) has been listed as the main agricultural technology to increase land utilization ratio and grain yield in Shandong province, China. However, little information is available on the optimized water and nitrogen management for yield formation, especially the grain filling process, under HLSC mode. A three-year field experiment with four nitrogen rates and three irrigation rates of HLSC was conducted to reveal the response of grain-filling parameters, grain weight percentage of spike weight (GPS), spike moisture content (SMC), and yield of winter wheat to water and nitrogen rates. The four nitrogen rates were N1 (360 kg ha-1 pure N), N2 (300 kg ha-1 pure N), N3 (240 kg ha-1 pure N), and N4 (180 kg ha-1 pure N), and three irrigation quotas were W1 (120 mm), W2 (90 mm) and W3 (60 mm). Results showed that the determinate growth function generally performed well in simulating the temporal dynamics of grain weight (0.989<R2<0.999, where R2 is the determination coefficient). The occurrence time of maximum filling rate (Tmax) and active grain-filling period (AGP) increased with the increase in the water or nitrogen rate, whereas the average grain filling rate (Gmean) had a decreasing trend. The final thousand-grain weight (FTGW) increased and then decreased with the increase in the nitrogen rates and increased with the increase in the irrigation rates. The GPS and SMC had a highly significant quadratic polynomial relationship with grain weight and days after anthesis. Nitrogen, irrigation, and year exerted highly significant effects on the Tmax, AGP, Gmean, and FTGW. Particularly, the AGP and FTGW were insignificantly different between high seedbed (HLSC-H) and low seedbed (HLSC-L) across the water and nitrogen levels. Moreover, the moderate water and nitrogen supply was more beneficial for grain yield as well as spike number and grain number per hectare. The principal component analysis indicated that the combination of 240-300 kg N ha-1 and 90-120 mm irrigation quota could improve grain filling efficiency and grain yield for the HLSC-cultivated winter wheat.

Dietary supplementation with pseudostellaria heterophylla polysaccharide enhanced immunity and changed mRNA expression of spleen in chicks

In recent years, increasing interest has focused on natural components extracted from plants, among which plant polysaccharides as natural immunomodulators that can promote animal immunity. The present study was performed to investigate the effect of feed supplement Pseudostellaria Heterophylla Polysaccharide (PHP) on serum Immunoglobulins, T lymphocyte subpopulations, Cytokines and Lysozyme (LZM) activity in chicks. In addition, the influence of PHP on splenic gene expression was investigated by transcriptome sequencing. Four hundred 7-day-old Gushi cocks were randomly divided into four groups in a completely randomized design. The chicks were fed with a basal diet supplemented with 0 (CON-A), 100 (PHP-L), 200 (PHP-M) and 400 (PHP–H) mg/kg PHP. Blood and spleen samples were collected from 6 randomly selected chicks in each group at 14, 21, 28, and 35 days of age. The results showed that compared to the CON-A group, the PHP-M group exhibited significant increases in the levels of IgA, IgG, IgM, CD3, and LZM in the serum at 14, 21, 28, and 35 days (P < 0.05), and at 28 d, there was a significant quadratic relationship between the levels of dietary PHP and the levels of IgG, IgM, IFN-γ, IL-2, CD3, and LZM. Furthermore, a total of 470 differentially expressed genes (DEGs) were identified in spleen from PHP-M and CON-A at 28 d. These DEGs were significantly enriched in the Phagosome, Intestinal immune network for IgA production and Cytokine-cytokine receptor interaction pathways. The present investigation highlights the ameliorating effect of dietary PHP on immunological variables and spleen of chicks, the study suggests that PHP supplementation can enhance immunity and positively impact spleen mRNA expression in chicks.

Effects of Lower Dietary Calcium and Phosphorus on Growth Performance and Bone Mineralizatıon of Broilers

This experiment was carried out to investigate the effects of reduced dietary calcium (Ca) and non-phytate-phosphorus (NPP) levels at 2:1 constant ratio on performance, carcase parameters and bone mineralization of Ross-308 broilers. A total of 11400 one-day-old chicks were randomly allocated to five dietary treatments with twelve replicates and were fed starter diets including either recommended (control treatment, T1) or a 6.25% lower level of both Ca and NPP according to breeder’s recommendations during starter period (SP). After SP, control treatment (T1) continued to be provided through diets containing 0.87 and 0.78 % Ca for grower (GP) and finisher periods (FP), respectively, while 6.25 % reduced group was divided into 4 dietary treatments regarding extent of decrease in Ca and NPP levels and provided by diets containing 0.79;0.65 (T2), 0.79;0.60 (T3), 0.75;0.65 (T4), and 0.75;0.60 (T5) % Ca for GP and FP, respectively. After SP, moderate and even substantial reduction of Ca and NPP significantly decreased feed intake (FI) (quadratic, P&lt;0.05), but obtained similar body weight gain (BWG) and FCR compared to the control (P&gt;0.05). On the other hand, reduced dietary Ca through T1 to T5 significantly decreased the total Ca and NPP intake of broilers (linear and quadratic, P&lt;0.01), and accompanied to significant linear and quadratic relationship between Ca intake and FCR and BWG respectively. It can be concluded that reducing Ca level down to 0.75 and 0.60 % in grower and finisher phase, respectively are possible without compromising the growth performance and bone mineralization of modern broilers.

Free amino acids in response to salinity changes in fishes: relationships to osmoregulation.

Free amino acids (FAAs) are believed to play important roles in osmoregulation and buffer capacity in some aquatic animals, such as fishes. However, the potential roles of FAAs have not been systematically summarized and characterized until now. In the present study, the meta-analysis was conducted to investigate the relationships between FAAs and environmental salinities. Twenty published documents were included, accounting for 106 study cases. The effect sizes of total free amino acids (TFAAs), total essential amino acids (TEAAs), and total non-essential amino acids (TNEAAs) to salinity increase were calculated and determined by the restricted maximum likelihood (REML) method. It clearly showed that the elevated salinities significantly induced the contents of TFAAs, TEAAs, and TNEAAs at the ratio of 36%, 27%, and 29%, respectively. Faced to the salinity changes, the contents of FAAs in fishes under freshwater and seawater varied significantly, while the individuals under brackish water displayed relatively constant contents of FAAs. When salinity elevated, the contents of 17 amino acids in muscles significantly increased, suggesting the important roles of FAA metabolism in osmoregulation in fishes. The results also indicated that the effect sizes of TFAAs were positively related to the rates of salinity increases, and exhibited a significant quadratic linear relationship with temperatures. Additionally, the contents of FAAs also showed positive correlation with osmotic pressure, concentrations of plasma Na+, Cl-, and urea, implying their potential roles of FAAs in osmoregulation in fishes. These findings suggested that elevated salinities greatly induced the contents of FAAs in fishes, making a great contribution to maintaining the homeostasis of fishes in response to environmental salinity changes.

Dietary propionate administration improves growth performance, hepatic lipid deposition, and intestinal activity of digestive enzymes, inflammation, bacterial population, and antioxidant capacity in rainbow trout, Oncorhynchus mykiss

The present study aimed to investigate the effects of dietary sodium propionate on growth performance, hepatic lipid deposition, and intestinal activity of digestive enzymes, inflammation, bacterial population, and antioxidant capacity in rainbow trout, Oncorhynchus mykiss. The fish were fed diets supplemented with 0 g/kg (CTL), 1 g/kg (P1), 2.5 g/kg (P2.5), or 5 g/kg (P5) sodium propionate for 70 days. The results showed significant (P < 0.05) linear or quadratic relationships between dietary sodium propionate levels and all tested parameters. Growth performance and feed efficiency significantly increased in the P1 and P2.5 treatments, but decreased in the P5 treatment, compared to the CTL group. Hepatosomatic index significantly decreased in the P1 and P2.5 treatments, but increased in the P5 treatment, compared to the CTL group. The P1 and P2.5 treatments exhibited significantly lower viscerosomatic indices than the CTL group. The P1 and/or P2.5 treatments exhibited significantly higher intestinal amylase, lipase, trypsin, chymotrypsin, superoxide dismutase (SOD), catalase (CAT), and lower intestinal malondialdehyde (MDA), plasma glucose, and triglyceride levels than the CTL treatment. On the other hand, the P5 treatment exhibited significant decrease in intestinal lipase, SOD, CAT, and higher intestinal MDA, plasma glucose, cortisol, triglyceride, and cholesterol levels than the CTL group. The intestinal total viable bacteria significantly decreased in the propionate treatments, and the lowest level was observed in the P2.5 treatment. The P1 and P2.5 treatments had significantly higher intestinal abundance of Lactobacillus sp. and lower Aeromonas hydrophila, Yersinia ruckeri, and Streptococcus iniae than the CTL group. The pathogenic bacteria showed significant elevations in the P5 treatment, compared to the CTL group. The propionate treatment groups showed significant up-regulations in intestinal heat shock protein 70 expression than the CTL group. The intestinal expression of tumor necrosis factor-alpha and interleukin-1 beta significantly decreased in the P1 and P2.5 treatments, while increased in the P5 treatment, compared to the CTL group. The intestinal expression of defensin significantly increased in the P1 and P2.5 treatments, while decreased in the P5 treatment, compared to the CTL group. In conclusion, dietary sodium propionate can improve the growth and intestinal health of rainbow trout. Based on the results, 2.5 g/kg sodium propionate is suitable for rainbow trout, but higher levels induce growth retardation, hepatic lipid accumulation, and intestinal oxidative stress, inflammation, and dysbiosis.

Inverted U-Shaped Relationship between Obesity Parameters and Bone Mineral Density in Korean Adolescents.

As the association between obesity and bone health remains controversial in children and adolescents, we investigate the effects of obesity parameters on bone mineral density (BMD) in 2060 Korean adolescents who participated in the 2008-2011 Korea National Health and Nutrition Examination Survey (KNHANES). Multiple regression analysis and analysis of covariance (ANCOVA) were conducted to examine both the linear and non-linear associations between total-body-less-head (TBLH) BMD and four obesity parameters: body mass index, waist circumference, waist-to-height ratio, and total-body fat mass (FM). In a multiple linear regression analysis adjusted for age, menarcheal status (in females only), and total-body lean mass, there was no significant linear association between obesity parameters and TBLH BMD, except for total-body FM in males. However, upon adding a second-order polynomial term for each obesity parameter, a significant quadratic relationship between all obesity parameters and TBLH BMD was observed, with the corresponding quadratic term being negative. The results of ANCOVA also revealed an inverted U-shaped relationship between each obesity parameter and TBLH BMD. Our findings suggest the existence of an optimal range of obesity parameters for developing or maintaining optimal bone health in Korean Adolescents. Deviation from this range, in either direction (being underweight or having obesity), may compromise bone health.

Biological nitrogen fixation in rice paddy soils is driven by multiple edaphic factors and available phosphorus is the greatest contributor

Biological nitrogen fixation (BNF) is important for sustainable rice cultivation. Various edaphic factors have been individually evaluated for their effects on BNF in paddy soils. However, no single factor could fully explain the different soil outcomes. Paddy BNF is more likely to be simultaneously influenced to various degrees by combinations of several factors; however, the relative importance of the interaction of multiple edaphic factors on the regulation of BNF in rice soils is still unclear. Twenty-seven paddy soil samples with different soil properties were collected from major cropping areas in southwest and northeast China. Rice was transplanted into pots of these soils and grown in a 15N2 enriched airtight chamber. Estimation of BNF was based on measurements of 15N enrichment in the different soils and rice plants at the end of a 77-d incubation period. BNF amounts ranged from 0.66 to 12.3 kg ha−1. BNF had a significant positive relationship with available phosphorus (AP) and significant quadratic relationships with available molybdenum (AMo) and total soil nitrogen (TN). AP explained 42% of the observed variation in BNF, TN explained 17%, and AMo explained 13%. The specific interaction between the soil cation exchange capacity (CEC) and available soil N (ASN, as determined by rice N uptake) accounted for 28% of the variation. BNF was reduced when AP was < 14 mg kg−1, AMo < 0.09 mg kg−1, or when TN was > 3.2 g kg−1. These results provide valuable benchmarks that could be used to guide farmers in managing their soils to improve the potential contribution of paddy BNF to soil fertility.

A quantitative analysis of the impact of reclamation on the stability of coastal wetlands

The ecological stability of coastal areas is seriously affected by tidal flat reclamation. Understanding the spatial characteristics of the impact of reclamation on stability, as well as the contribution of different use types of reclamation to stability change, is important for mitigating the negative effects of reclamation. In this study, multi-source and multi-temporal remote sensing images were combined to quantitatively analyze the relationship between reclamation and stability in different regions of the coastal area in Jiangsu Province, as well as the relative contribution of different use types of reclamation to the stability change. The results showed that: Different forms of statistical relationships between reclamation and stability existed in reclaimed area and non-reclaimed area, respectively, while a significant quadratic function relationship existed in the whole affected area, and the stability index decreased first and then increased with the increase of reclamation amount, with a threshold of 1243 km2; In different buffer zones within the non-reclaimed area, the impact intensity of reclamation showed spatial decay characteristics; The use type of reclamation that has the greatest impact on stability in the reclaimed area is aquaculture land, while in the non-reclaimed area it is arable land. In addition, aquaculture land, arable land and hydraulic engineering land have negative effects on stability, while salt industry land has positive effects.

Managerial ownership and the effectiveness of internal control

This paper examines the impact of managerial ownership on the effectiveness of internal control in China's stock markets, focusing on the perspective of managerial ownership. The findings reveal a significant quadratic non-linear relationship, characterized by an inverted-U shape, between the level of managerial ownership and the effectiveness of internal control for the overall population of listed companies. Notably, the inverted U-shaped effect of managerial ownership on internal control is observed to be more delayed in non-state-owned listed companies. However, these companies exhibit a stronger incentive effect, and the 'Entrenchment Effects' become apparent at an earlier stage.