Effect Of Reduction Research Articles

Root physiological and morphology processes co-regulate the growth of Chinese-fir saplings in response to warming and precipitation reduction in the sub-tropical regions

Subtropical China is projected to experience elevated temperature greater than the mean global temperature increase and is accompanied by reduced precipitation. The plasticity of roots to changing environment strongly influences ecosystem feedbacks to climate change. However, knowledge gaps on the individual and combined effects of warming and precipitation reduction on root systems hinder our ability to accurately predict the growth and adaptability of forests under future climate change. To examine the effects of warming (W) and precipitation reduction (P) on roots physiology and morphology of Chinese-fir saplings, we used a randomized complete block design with factorial soil warming (ambient, ambient + 5℃) and precipitation reduction (ambient, ambient-50%) treatments. A full excavation method was adopted to obtain roots, then we measured the root physiology (osmoregulatory substances, oxidant substances, protective enzymes, endogenous hormones), morphology (specific root length, SRL; surface root area, SRA; root tissue density, RTD). The content of carbon and nitrogen, isotopes (δ13C and δ15N); soil temperature, soil moisture and sapling growth were also measured. We found that compared with the control, W decreased the abscisic acid (IAA) content; P increased the contents of hydrogen peroxide (H2O2) and proline (Pro), and decreased the contents of IAA and cytokinin (CTK); warming plus precipitation reduction (WP) increased the Pro content, and decreased the contents of IAA and CTK. In addition, the effects of W and P on root morphology varied with soil depth and root diameter class. W, P, and WP all increased fine root SRL and SRA in deep soil. Warming and precipitation reduction could affect physiological traits (e.g. non-enzymatic substances and antioxidant enzymes) and subsequently morphological traits via influencing soil environment and root tissue chemistry. Collectively, the results indicated that Chinese-fir saplings responded to warming and precipitation reduction by comprehensive regulation of the non-enzymatic substances (e.g., osmotic substances and endogenous hormones) of fine roots and changing root morphological characteristics in deep soil.

Elucidating the role of weight loss and glycaemic control in patients with type 2 diabetes.

To investigate the independent contributions of glycated haemoglobin (HbA1c) reduction and weight loss to clinical outcomes in patients with type 2 diabetes (T2D) treated with antidiabetic drugs, including glucagon-like peptide-1 receptor agonists (GLP-1RAs). This observational, retrospective cohort study used deidentified electronic health record-derived data from patients evaluated at the Cleveland Clinic (1 January 2000-31 December 2020). Cohort A included 8876 patients with newly diagnosed T2D treated with any of six antidiabetic drug classes. Cohort B included 4161 patients with T2D initiating GLP-1RA treatment. The effects of body mass index (BMI) and HbA1c reduction, variability, and durability on clinical outcomes were investigated. In Cohort A, each 1% BMI reduction was associated with 3%, 1%, and 4% reduced risk of heart failure (p = 0.017), hypertension (p = 0.006), and insulin initiation (p = 0.001), respectively. Each 1% (~11 mmol/mol) HbA1creduction was associated with 4% and 29% reduced risk of hypertension (p = 0.041) and insulin initiation (p = 0.001), respectively. In Cohort B, each 1% BMI reduction was associated with 4% and 3% reduced risk of cardiovascular disease (p = 0.008) and insulin initiation (p = 0.002), respectively. Each 1% (~11 mmol/mol) HbA1c reduction was associated with 4% and 16% reduced risk of chronic kidney disease (p = 0.014) and insulin initiation (p = 1 × 10-4), respectively. Lower BMI variability and greater BMI durability were associated with decreased risk of clinical outcomes in both cohorts. Antidiabetic medication-associated, and specifically GLP-1RA-associated, weight loss and HbA1c reductions independently reduce real-world clinical outcome risk.

Case Study Analysis on the Flood Mitigation Effects of Improving a Drainage System Using Low Impact Development Techniques

Low-impact development (LID) techniques aim to minimize the hydrological and environmental impacts associated with watershed development by preserving the natural state as much as possible, reducing impervious surfaces, managing stormwater on a small scale at the point of generation, and promoting decentralized stormwater management. In this study, the flood reduction effects of LID techniques were analyzed using PCSWMM by comparing traditional development methods in the Songsan Green City development project. In this process, the LID technique considers nonstructural methods of diversifying drainage directions and structural methods of introducing vegetated swales to improve the drainage system. The results showed that the LID approach, introduced to improve the drainage system, had a significant effect on reducing floods and inundation compared to traditional development methods. The results of this study suggest the potential of using LID techniques in structural and nonstructural approaches to improve urban flooding and inundation problems.

A Study on the Analysis of Reduction Effects and Comparison of Economic Feasibility by Applying the LID Technique

This study conducted a comparative review of the effects and project costs of four different flood runoff reduction measures applied in the Dongnam District 1 watershed. Using the XP-SWMM model, the effects of three LID (low-impact development) technologies—infiltration trenches, permeable pavement, and green roofs—were analyzed. The results showed reductions in both peak flood discharge (32.65 m<sup>3</sup>/s → 27.85 m<sup>3</sup>/s) and total runoff volume (99,725 m<sup>3</sup> → 86,814 m<sup>3</sup>). However, the application of LID technologies alone is insufficient for mitigating flood risks. Therefore, flood reduction measures were categorized into four CASEs, combining LID technologies with conventional stormwater management facilities. The cost comparison for each CASE was as follows: CASE 1 (LID + pump) at 22.3 billion KRW, CASE 2 (LID + stormwater storage facility) at 20.3 billion KRW, CASE 3 (pump) at 20.6 billion KRW, and CASE 4 (stormwater storage facility) at 21.0 billion KRW. Despite the use of LID technologies, the project costs for CASEs 3 and 4, which utilized existing reduction methods, were higher. This indicates that integrating LID technologies with conventional reduction measures is likely the most effective approach.

Combined Effect of Noise Reduction, FBS-Based Spectral Splitting, and Dynamic Range Compression of Speech Signal on Source Localization in Binaural Hearing Aids

Localizing sound sources in three spatial dimensions (azimuth, elevation, and distance) is critical for human hearing comfort. It relies on two binaural cues: interaural time difference (ITD) and interaural level difference (ILD). Cochlear or auditory nerve injury can result in sensorineural hearing loss (SNHL). Hearing aids enable people with sensorineural hearing loss to converse more effectively and hear better. However, there is an apprehension that the binaural hearing aids may degrade the localization cues, thus affecting the source localization. In response to this concern, the current study investigates how the binaural hearing aid algorithm affects source localization by adopting a cascaded structure of noise reduction technique (wiener filter) followed by filter bank summation (FBS) based spectral splitting and dynamic range compression for binaural dichotic presentation. Listening tests for seven different azimuth angles (-90⁰, -60⁰, -30⁰, 0⁰, 30⁰, 60⁰, and - 90⁰) were conducted on six listeners with normal hearing under different signal-to-noise ratio (SNR) conditions as well as on six subjects with mild bilateral sensorineural hearing impairment. Test stimuli included background glass-breaking sound and broadband noise for participants with normal hearing. In an experiment with hearing-impaired subjects, the glass-breaking sound served as one of the test stimuli. The result showed that these binaural hearing aid algorithms had no adverse effects on localization ability.

Environmental benefits of crude protein reduction in growing pig diets: Is it worth going further?

Nitrogen (N) excretion and emissions can be reduced in fattening pigs by reducing dietary crude protein (CP) level. Effects of this strategy are well documented for moderate CP reduction, but little literature exists on further CP reduction made possible by free isoleucine, histidine, and leucine. This trial evaluated the effects of two levels of reduction in CP on growth performance, N balance, and gaseous emissions. Forty-eight pigs were allocated to 12 gaseous emission-measuring chambers at 28kg live weight. Three dietary treatments (CTRL; -1.2pt; -2.4pt), with a CP content, respectively, of 18.1%, 16.9%, and 15.0% in phase 1 (28-48kg) and 16.1%, 15.0%, and 13.8% in phase 2 (48-80kg), were fed ad libitum. Growth performance was recorded for each phase. Body lipid and protein composition were analyzed by dual-energy X-ray absorptiometry in two animals per chamber at the beginning and end of the trial. These results were used to calculate the N balance. Slurry volume and composition were measured at the end of the trial. Ammonia, methane, and nitrous oxide emissions were recorded continuously. Data were analyzed with a general linear model including the linear and quadratic effect of CP reduction and phase as fixed effects. A trend for a quadratic effect of CP reduction on feed intake was observed (P = 0.085) with a decrease from CTRL to -1.2pt and then an increase with the -2.4pt treatment. Daily gain and gain to feed were improved by the low-CP diets in phase 1 but were degraded in phase 2 (phase × CP interaction, P < 0.001) while body composition was not affected. Nitrogen excretion decreased with CP reduction (linear effect, P = 0.023) but tended to plateau with the low-CP diets (quadratic effect, P = 0.081). Methane emissions per kg of gain were reduced with CP reduction (linear effect, P = 0.031). Ammonia emissions decreased with CP reduction, mostly in phase 1 (phase × CP interaction, P = 0.015); however, the emission factor (g N-NH3 / g urinary N) was not affected. Nitrous oxide emissions were not affected by CP reduction and its emission factor (g N-N2O / g N) tended to increase (linear effect, P = 0.07). Slurry ammonia-N decreased (linear effect, P < 0.023; quadratic effect, P = 0.049), but other slurry components were not significantly impacted. In this trial, a plateau in N excretion and emission reduction was reached with the -2.4pt treatment. Nevertheless, it is important to study such a reduction in conditions closer to commercial ones.

Effect of Experimental Litter Reduction on Cerebellum Development in Suckling Rats.

We studied morphological features of the cerebellum in 14-day-old Wistar rats from reduced litters (the number of pups was reduced from 10-12 to 6 on the next day after birth). The control group comprised 14-day-old animals from litters of medium size (10-12 rat pups). Rats from reduced litters had greater body weight and brain weight. The weight of the cerebellum, together with the weight of the adjacent part of the brain stem and the thickness of cerebellar cortex also significantly exceeded the corresponding parameters in control animals. The thickness of the molecular layer of the cerebellar cortex and the numerical density of Purkinje cells in these rats did not differ significantly from the control. The thickness of the external granular (neurogenic) layer of the cerebellar cortex in rats from reduced litters was smaller. This can indicate accelerated reduction of this layer that persists in rats until days 20-22 of age. Numerical density of cells in the external granular layer of control and experimental animals was similar. Numerical density Ki-67+ cells in this layer, as well as GFAP+ glial cells in the granular layer of the cerebellar cortex in rats from reduced litters significantly exceeded the corresponding parameters in control animals. The cerebellum of rats from litters reduced 1 day after birth had a number of differences in important indicators reflecting the rate of its development during the neonatal and suckling periods of ontogeny.

Productive, Physiological, and Environmental Implications of Reducing Crude Protein Content in Swine Diets: A Review

Pig production is one of the most important providers of high-quality proteins and amino acids (AAs) to human nutrition. In this sector, feeding has an important economic and environmental impact. A strategy to reduce production costs and negative sustainability effects is reducing dietary crude protein (CP) contents with or without AA supplementation. This review addresses the different aspects related to this strategy, particularly the effects on growth performance and pork traits in piglets and growing and finishing pigs, as well as the physiological molecular mechanisms’ underlying effects. Insight is also provided into the effects of dietary CP reduction on the productive performances of alternative pig production systems and breeding boars and sows. Finally, an overview is conducted on the effects of dietary CP reduction on ammonia, odor, and greenhouse gas emissions arising from pig production systems. Overall, CP reduction may lead to production losses, albeit they can be, to some extent, hindered by adequate AA supplementation. Losses are particularly relevant during the post-weaning phase, whereas in finishing pigs, it may bring additional benefits, such as high intramuscular fat contents in some markets or improved gut barrier function with benefits to the animals’ health and welfare, as well as decreased ammonia emissions to the environment.

Assessing causality in deprescribing studies: A focus on adverse drug events and adverse drug withdrawal events.

Generating real-world evidence about the effect of medication discontinuation or dose reduction on outcomes, such as reduction of adverse drug effects (ADE; intended benefit) and occurrence of adverse drug withdrawal events (ADWE; unintended harm), is crucial to informing deprescribing decisions. Determining the causal effects of deprescribing is difficult for many reasons, including lack of randomization in real-world study designs and other design and measurement issues that pose threats to internal validity. The inherent challenge is how to identify the effects, both intended benefits and unintended harms, of a new medication stoppage or reduction when implemented in patients with many potential clinical and social risks that may influence the likelihood of deprescribing as well as outcomes. We discuss methodological issues of estimating the effect of medication discontinuation or reduction on risk of ADEs and ADWEs considering: (1) sampling study populations of sufficient size with the potential to demonstrate clinically meaningful and quantifiable outcomes, (2) accurate and appropriately timed measurement of covariates, outcomes, and discontinuation, and (3) statistical approaches to managing confounding and other biases inherent in long-term medication use by individuals with multiple morbidities. Designing rigorous deprescribing studies that address internal validity threats will support evidence generation by improving the ability to assess benefits and harms when the exposure of interest is the absence of a medication. Iterative learnings about data quality, variable definition, variable measurement, and exposure-outcome associations will inform strategies to improve the causal inferences possible in real-world deprescribing studies.

Investigating the determinants of consumer confidence and online impulse buying intentions: an experimental study

PurposeThis study examines the effects of risk reduction, seller reputation, eWOM and warranties on consumer confidence and online impulse buying intentions through the lens of the stimulus-organism-response (SOR) model. It also explores the role of installment options in online impulse buying.Design/methodology/approachWe performed a between-subjects experiment (installment vs. no-installment option). Data were collected from 199 consumers and analyzed using SmartPLS 3.3.9.FindingsThe results show that risk reduction, eWOM and warranty positively affect consumer confidence (CC) in online shopping and that CC positively predicts online impulse buying intentions. It was also found that the effect of CC on online impulse buying intentions was stronger when consumers were offered an installment option than a no-installment option.Practical implicationsFindings suggest that online sellers should invest more resources in building consumer confidence, which affects online impulse buying intentions. Moreover, online sellers should offer installment options to consumers, thereby reaping stronger effects of consumer confidence on online impulse buying intentions.Originality/valueEmploying the experimental approach, this study makes a novel attempt to examine the role of the installment option in fostering online impulse buying intentions among Pakistani consumers. Likewise, this is one of the early studies to explore the effects of risk reduction, seller reputation, eWOM and warranties on CC among Pakistani consumers using the SOR model.

Overall survival after CDK4/6 inhibitor dose reduction in women with metastatic breast cancer

BackgroundBreast cancer is the most common cancer in women, and the first-line treatment for patients with hormone-receptor positive/HER2-negative metastatic breast cancer is CDK4/6 inhibitor plus endocrine therapy. Understanding the impact of CDK4/6 inhibitor dose reduction, which occurs in about half of the patients, is important.MethodsThis real-world cohort study is based on electronic health records from Capital Region of Denmark. All women with metastatic breast cancer initiating first-line treatment with CDK4/6 inhibitor between May 2017 and October 2022 were included.ResultsA total of 546 patients were eligible for inclusion in the 12-week landmark analysis and 192 (35%) experienced dose reduction. These patients were older, had worse ECOG PS, more received prior adjuvant endocrine treatment, and more received fulvestrant as the endocrine backbone. Dose reduction was associated with reduced overall survival (39.9 vs. 54.3 months) and shorter treatment duration (18.0 vs. 26.9 months). Adjusted hazard ratio for death was 1.38 (95% CI: 1.01–1.89).ConclusionsDose reduction of CDK4/6 inhibitors within the first 12 weeks of treatment was associated with significantly higher mortality and shorter treatment duration. These findings contrast with previous analyses showing no effect of dose reduction, likely due to considering immortal time bias in this study.

Study on the Sand Reduction Effect of Slope Vegetation Combination in Loess Areas

Slope erosion in the Loess Plateau region has long been a concern, and vegetation plays an important role in slowing down erosion and controlling sedimentation. However, a single vegetation model shows some limitations when facing complex natural conditions and variable rainfall events. Therefore, this study investigated the influence mechanism of vegetation configuration on slope sand production at different slopes through theoretical analyses and indoor experiments. The results of the study showed that certain factors, such as vegetation configuration mode, flow rate, runoff power, runoff velocity, and runoff shear, are closely related to slope runoff sand production. The specific findings are as follows: (1) Under the condition of slope gradient of 2°, the sand reduction effect of the rigid–flexible single-row staggered configuration is the most significant, and the sediment production is reduced by 29.89%. (2) With the increase in the slope gradient and flow rate, the sand production on the slope surface rises significantly, and when the slope gradient is increased from 2° to 6°, the average sand production is increased from 1.43 kg to 2.51 kg.(3) The erosion reduction effects of different vegetation configurations were in the order of rigid–flexible single-row staggered combination &gt; flexible vegetation single combination &gt; rigid–flexible double-row staggered combination &gt; rigid vegetation single combination &gt; upstream rigid downstream flexible combination &gt; bare slope. This study provides a theoretical basis for optimizing the vegetation configuration for effective sand reduction and provides an important reference for the sustainable development of the Yellow River Basin.

A review of general cognitive-behavioral programs in English and Welsh prisons and probation services: Three decades of quasi-experimental evaluations.

For over 30 years, general cognitive-behavioral programs have contributed to the rehabilitation services offered within His Majesty's Prison and Probation Service in England and Wales. There is an extensive body of international evidence that demonstrates the effectiveness of such interventions as a correctional strategy. However, there is widespread variability of program effects associated with the standards of implementation. Over the last 3 decades, British researchers have produced a steady output of quasi-experimental program evaluations that have contributed to the evidence base. The most recent additions are some of the largest and most rigorous available worldwide. This review documents those evaluations and provides a meta-analysis that statistically aggregates the effects of programs delivered in His Majesty's prisons in England and Wales. We suggest there is sufficient evidence from evaluations of acceptable scientific rigor to conclude that general cognitive-behavioral programs delivered in prisons during the last decade and a half (circa 2006 to 2019) have had a small statistically significant mean reductive effect on general reoffending (odds ratio = 0.91). Program characteristics and implementation factors, including program dose, the scale of service delivery and program integrity, are discussed as possible factors associated with the size of the effect. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Reverse design and application of phononic crystals based on deep learning

Abstract This paper reverse-design phononic crystals with band gaps within a targeted frequency band using the trained Conditional Variational Autoencoder (CVAE) and further studies the vibro-acoustic characteristics of a composite sandwich plate with a phononic crystal panel as the core layer. Firstly, a matrix composed of 0s and 1s, representing scatterers and substrates, is randomly generated by MATLAB to represent two-dimensional phononic crystals. The three-dimensional phononic crystals are obtained by stretching the two-dimensional phononic crystals along the average direction, and COMSOL Multiphysics is used to calculate the band gap. In order to maximize the production of phononic crystals with a band gap distribution, the Convolutional Neural Network (CNN) is trained to predict whether the generated phononic crystals have band gaps. Finally, using data on the structures of phononic crystals and their band gap distributions, the CVAE is trained to achieve the reverse design of artificial periodic structures based on the target band gap. To verify the effectiveness of the structures obtained through the reverse design method on vibration and noise reduction, the submerged vibro-acoustic characteristics of a composite sandwich plate consisting of a phononic crystal panel and carbon fiber panels are studied. The model of the composite sandwich plate is fabricated, and its submerged vibro-acoustic characteristics are tested and compared with numerical results. Finally, the submerged vibro-acoustic response levels of composite sandwich plates with phononic crystal panels and honeycomb panels as core layers are compared using numerical methods to assess the phononic crystal panel's vibration and noise reduction effects.

Comparative assessment of pollution control measures for urban water bodies in urban small catchment by SWMM

Under the current increasingly serious water pollution situation in urban, the comprehensive treatment and protecting measures in urban small catchment are the necessary step to the water pollution treatment, not only focus on the water bodies themself. In this paper, the Luojiagang river channel and its catchment in Wuhan, which has been heavily impacted by water pollution, are taken as an example for the comparative assessment of pollution control measures in order to explore the effective and sustainable schemes including the LID (Low Impact Development---LID) by using SWMM model (Storm Water Management Model---SWMM). Through the comparison of pollution treatment measures based on scenarios simulation with the baseline scenarios, it was found that the reduction effects of pollutant peak concentrations at the outlet node of Luojiagang River had the decreasing order of: the combined measures (COS) &amp;gt; LID control &amp;gt; the water diversion from Donghu Lake (WAD) &amp;gt; the sewage treatment (SET) &amp;gt; the sediment dredging (SED), and the reduction effects of total pollutant load had the decreasing order of: LID &amp;gt; COS &amp;gt; SET &amp;gt; SED &amp;gt; WAD. The results show that the control of non-point source pollution is the key for the improvement of water quality in Luojiagang River, and LID plays important role in the reduction of both pollutant peak concentrations and load. This study has the implication for the decision making of the water pollution controlling schemes in urban small catchment.

Achieving collaborative pollutant and carbon emissions reduction through digital governance: Evidence from Chinese enterprises

Under China's dual carbon goals, it is imperative for enterprises to effectively reduce carbon emissions while achieving pollutant reduction. This article explores the potential role of government-implemented digital governance in facilitating these objectives. Utilizing a quasi-natural experiment on digital governance, we established an analytical framework to thoroughly examine how digital governance can help Chinese enterprises realize synergistic effects in pollution control and carbon reduction. Our study reveals that digital governance significantly reduces enterprises' emissions of carbon dioxide and pollutants, with emission intensities of the carbon dioxide, air pollutant and water pollutant being decreased by approximately 6.9%, 7.3%, and 7.0%, respectively. These reductions are primarily driven by improvements in energy efficiency, the promotion of green innovation, digital transformation, and enhanced role of media. However, it is important to note that digital governance also negatively impacts overall corporate productivity and widens the digital divide between large and small-to-medium enterprises. The research results have practical significance for promoting the achievement of emission reduction goals and sustainable development for enterprises.

Comparative efficacy of PsyPills and OCAT mobile psychological interventions in reducing depressive, anxiety and stress symptoms: A blinded randomized clinical trial

BackgroundDigital applications, such as in smartphone apps format, have shown high suggestive evidence for their efficacy in reducing general distress, but rigorous studies of their efficacy in symptom change and the mechanisms involved are still needed. MethodsIn the current multi-arm parallel-group randomized trial, participants aged 18–65 with smartphone access were recruited through social media. They were randomly assigned to two app interventions (PsyPills and OCAT) or an active placebo group (shamOCAT). The primary outcome was psychological distress measured up to one month. ResultsA total of 229 participants from diverse regional and demographic groups of the general population of Romania were randomly allocated into the three groups (PsyPills n = 80; OCAT n = 70; shamOCAT n = 79) and included in intention-to-treat analyses. Both the PsyPills (MD = −522; 95%CI = −10.00 to −0.44; d = 0.48) and OCAT (MD = −6.30; 95%CI = −11.39 to −1.21; d = 0.58) reduced significantly, with medium effect sizes, the psychological distress levels compared with the control group at follow-up. For the separate outcomes, only PsyPills showed significant medium reduction effects for anxiety symptoms (MD = −2.17; 95%CI = −3.83 to −0.50; d = −0.60), while OCAT showed reduction effects of small size for depression (MD = −1.50 (95%CI = −3.53 to 0.54, d = −0.34), that was however statistically nonsignificant. LimitationsWe registered high attrition and low adherence rates. Also, lower-than-planned effects might have been statistically underpowered to detect. ConclusionThe results support the high potential of both apps as scalable tools to provide low-intensity self-guided interventions for common psychological problems in the general population and expand opportunities for further research (e.g., confirm and capitulate on the differential effects).

Rupture energy coupling of alkali washing tower cylinder

The energy generated by the container during the explosion induces destructive effects on the surrounding objects and itself, such as deformation, compression, rupture, etc. The explosive energy is one of the richest pieces of evidence in the analysis of the accident cause, and therefore a comprehensive analysis of the accident explosive energy is essential for determining accident properties. Considering the rupture accident of an alkali washing tower in an aromatic hydrocarbon plant as an example, the destructive energy and the rupture internal pressure are estimated to ascertain the explosive properties of the accident by analyzing the field damage characteristics. This study aims to conduct a comprehensive analysis and calculation of the energy associated with an alkali washing tower rupture accident. The objective is to determine the cause of the accident, which can be attributed to the combined effect of wall thickness reduction and fluctuations of production process parameters. The findings of this analysis will serve as a scientific basis for the examination of similar accidents and the formulation of safety protection measures.

Effects of wall heating on wall pressure fluctuations and flow noise in a low-Reynolds-number turbulent channel flow with temperature-dependent viscosity

Wall pressure fluctuations and flow noise substantially degrade sonar detection performance and the acoustic stealth performance of underwater vehicles. This paper numerically investigates the effects of wall heating on wall pressure fluctuations in turbulent channel flow of water with temperature-dependent viscosity, exploring a novel method for controlling wall pressure fluctuations and flow noise in underwater vehicles. Large-eddy simulation (LES) is employed for the numerical calculation of the flow field, while a hybrid method combining LES with Lighthills acoustic analogy is employed to predict flow noise. The numerical results show that when the temperature difference between the wall and the incoming flow is 30 K and 50 K, the peak root-mean-square pressure fluctuations decrease by 6.76% and 8.91%, respectively. Wall heating stabilizes the pressure field near the wall, with the spectral levels of wall pressure fluctuations showing average decreases of approximately 1 dB and 2 dB. Wall heating weakens the energy-containing structures of wall pressure fluctuations and increases the overall convection velocity by 1.22% and 3.81%, respectively. Flow structure analysis reveals that the weakening of energy-containing structures results from the suppression of the vortex structures in the near-wall region. In the wall heating cases, peak turbulent kinetic energy decreases by 12.6% and 15.8%, respectively. Moreover, the sound pressure level of flow noise decreases with increasing wall temperature, with the maximum noise reduction exceeding 3 dB. Previous studies have not yet explored the effects of viscosity reduction caused by wall heating on wall pressure fluctuations and flow noise. This study demonstrates that wall heating is a promising method for reducing wall pressure fluctuations and flow noise.

How to evaluate the reduction effect of the park on PM2.5? Exploratory application of the maximum and cumulative perspective

Urban parks have been widely proved to be effective in reducing particulate matter pollution, but there is still a knowledge gap in quantitatively evaluating their reduction effects. The purpose of this study is to develop a new method to quantify the reduction effect of PM2.5 in urban parks through high-precision spatio-temporal monitoring experiments in 22 typical urban parks in Shenyang, China, so as to fill this gap. In this study, the cubic polynomial function model was used for the first time to establish the relationship curve between PM2.5 concentration inside and outside the park at different distances. The results showed that the park PM2.5 reduction magnitude and distance were about 5.04–10.14 ug/m3 and 149.47–150.19 m, respectively. Partial correlation analysis revealed that the relationship between the reduction evaluation indexes and the environmental factors had time heterogeneity. The park's internal characteristics and surrounding building environment was the key factor affecting the park PM2.5 reduction effect. In addition, parks smaller than 4.71 hm2 demonstrated better PM2.5 reduction efficiency. In conclusion, this study provides a new quantitative approach to evaluating the park PM2.5 reduction effect and offers data-driven insights for optimizing park planning to enhance the permeability of these effects beyond park boundaries.