Factorial Experimental Design Research Articles

Effects of early predation and social cues on the relationship between laterality and personality.

Individual differences in laterality and personality are expected to covary, as emotions are processed differently by the two hemispheres, and personality involves emotional behavior. Fish species are often used to investigate this topic due to the large variability in personality and laterality patterns. While some species show a positive relationship between lateralization strength and boldness, others show a negative relationship, and some show no relationship. A new way to assess the robustness of such a relationship is to manipulate both laterality and personality to examine how this affects their relationship. To this end, we conducted a fully factorial design experiment manipulating predation and group size during early development. Results showed that the strength of laterality was influenced by predation threat, while social tendency and boldness were influenced by group size. These findings suggest that early life conditions can have an impact on laterality and social behavior. The relationship between laterality and personality traits, while present, was heavily influenced by the specific trial conditions but not by the different developmental conditions. In summary, the relationship between laterality and behaviors appears to be context-dependent, yet resilient to early environmental manipulations.

TRUST–POWER RELATIONSHIP AND TAX REPORTING BY PLATFORM WORKERS: A MODERATED MEDIATION MODEL

The power and trust relationship between tax authorities and taxpayers is thought to be important in shaping taxpayer compliance behaviour. Although a growing number of studies have considered moral and emotional elements in tax decision-making, the nexus between taxpayers’ honest intention and feelings of guilt towards their tax-reporting decision remains unclear. In support of studies on the digital or platform economy and the rising number of individuals earning income digitally, this study seeks to identify factors that influence individuals’ tax reporting decision of their digital income. Applying the Slippery Slope Framework, this study uses a 2 x 2 between-subjects factorial experimental design, in which the independent variables of this study, i.e., power and trust are manipulated. This study conducts a scenario-based experiment with eighty platform workers on an established digital platform. The findings reveal that high trust in authorities increases platform workers' intention for honesty reporting and guilt for misreporting, promoting tax-reporting compliance. Moreover, this relationship is significantly moderated by the high-power condition. Specifically, it is believed that both enforcement and trust matter in achieving compliance in taxpayers’ reporting.

Multivariate evaluation from electrocoalescence to Brazilian crude oils in pilot plant scale

A multivariate evaluation of the electrocoalescence process for crude oil dehydration is presented in this study. The objective is to assess the impact of operational variables and their combined effects on the final water content. To achieve this, a pilot plant unit was constructed for the evaluation of five operational variables in a steady-state regime. The statistical analysis, conducted using results obtained through a factorial experimental design for three types of crude oil, illustrates how the influence of cross-effects impacts dehydration. Different responses from each type of crude oil depend on the combined variables. The findings highlight that a combination of factors, not always immediately apparent, contributes to a reduction in the final water content. Furthermore, the combination of operating factors appears to be more crucial than individual variables. This suggests an opportunity for the optimization of electrocoalescers by simply adjusting field parameters.

CORRELATION BETWEEN COMPOSITION OF MASONRY BLOCKS USING RECYCLED RUBBER AGGREGATES AND PROFITABILITY OF PRODUCTION LINE

A correlational study between the composition of masonry blocks with recycled rubber aggregates and the profitability of their production line was carried out. Masonry blocks were designed and manufactured with different contents of rubber aggregates from end-of-life tires. We started from a factorial design of experiments with response surface L4 (22). The factors considered were aggregate granulometry, water/cement ratio and rubber content. The outputs of the experiment were the ultimate compressive strength and the profitability of the production line (IRR/NPV). A model was defined that correlates the input factors with the defined responses. Through an ANOVA, the significant factors on the profitability of the production line in different production scenarios were determined. It was found that there is an inversely proportional relationship between the amount of rubber aggregate and the compressive strength. The maximum aggregate content that allows meeting the resistance requirements of the NTE INEN 3066 standard was 10% (p/p). On the other hand, from the economic-financial analysis it is concluded that the maximum economically profitable rubber content is 5% (p/p). These results make it possible to define the limits of profitability of a production line of masonry blocks that comply with current regulations.

IMPACTO DEL USO DE DOLOMITA Y OLIVINO EN EL PROCESO DE GASIFICACIÓN DE DESECHOS SÓLIDOS DE NARANJA. CONTRASTE CON LA GASIFICACIÓN SIN EL USO DE CATALIZADORES

The industry processing of the orange generates high volumes of solid waste. This waste has been used to complement animal feeding and biochemical processes, but the gasification process has not valued its energy use. Gasification studies were carried out with air in a catalytic fluidized bed (using dolomite and olivine as catalysts in a secondary reactor, also varying the temperature of the secondary reactor and the catalyst mass) of the solid waste of orange, and the results are compared with those obtained in the gasification with non-catalytic air. In the processes, we use a design of a complete factorial experiment of 2k, valuing the influence of the independent variables and their interactions in the answers, using the software Design-Expert® and a grade of the significance of 95 %. The results demonstrate the qualities of the solid waste of orange in the energy use through the gasification process for the treatment of these residuals, obtaining a gas of low heating value. The use of catalysts also diminishes the yield of tars obtained in the gasification process, making dolomite more active than olivine. The better results of fluidized bed catalytic gasification of RSNs, in terms of gas heating value, gas yield, and low tar yield, are obtained when the secondary reactor operates at a temperature of 800 ºC and using 60 g of dolomite as a catalyst. Keywords: Orange waste, catalytic gasification, fluidized bed, dolomite, olivine

Combined hydroxyphenyl-modified adhesive with the ion-pair strategy for long-lasting delivery of clonidine in single-layer matrix-type patch

Existing long-acting patches usually use controlled-release membranes to achieve constant rate delivery of the drug, which is complex and costly to prepare due to the 5-layer structure, so there is a necessity to develop a method to simplify the patch design and to control constant rate drug delivery. This study prepared a 7-day long-acting clonidine (CLO) patch using the ion-pair strategy based on hydroxyphenyl-modified pressure-sensitive adhesive (HP-PSA) and clarified the molecular mechanism of controlled delivery. Single factorial and central composite design (CCD) experiments were used to optimize the patch formulation, which was evaluated by a pharmacokinetic study. The controlled drug delivery mechanism was investigated by FTIR, 1H NMR, differential scanning calorimetry (DSC), confocal laser scanning microscopy (CLSM), molecular modeling, and rheology study. The optimized patch was formulated with 4.80% (w/w) CLO-AA (azelaic acid) as API and HP-PSA as PSA matrix and 95.00 μm thickness. The single-layer patch not only simplifies the preparation process but also has a zero-level skin penetration profile (r = 0.9592) in vitro. Compared with the commercial patch (AUC0-t = 7748.51 ± 662.76 h ng/ml, MRT0-t = 71.04 ± 9.30h), the pharmacokinetic behavior of the optimization group was semblable (AUC0-t = 8160.28 ± 694.04 h ng/ml, MRT0-t = 63.19 ± 12.38h). Mechanistic studies showed that ion-pair improved drug interaction with HP-PSA, leading to controlled drug release. Changes in drug physicochemical properties decreased skin permeability and increased drug-skin interaction, resulting in a constant delivery rate. In conclusion, the 7-day long-acting drug delivery of the CLO patch was achieved by the ion-pair strategy, which simplified the preparation process, and inspired a long-acting transdermal drug delivery system.

A Prospective Comparison of Materials and Structures for Sports Graduated Compression Socks

Abstract Compression socks have an effective role in the performance activity of athletes. This study aims to quantify the effect of fiber materials and structure on physical, mechanical, thermo-physiological, sensorial, and ergonomic comfort on sports graduated compression socks (SGCS). Two natural fibers, cotton and viscose, and two synthetic fibers, Coolmax and acrylic, were used to develop three different types of SGCS. Data have been analyzed by full factorial design of experiment. The finding exhibited that Coolmax-based socks have better moisture management and dimensional properties as compared with other materials. Acrylic-based SGCS are better to use in winter because of their higher thermal resistance, besides moderate moisture management. Moreover, it is verified that higher bursting strength is achieved by using higher-strength fibers. Additionally, it was observed that the effect of structure and material on desired properties without compromising compression/interface pressure is statistically significant. The overall properties of the developed stockings are better in terms of properties than market stockings. For all the socks, compression pressure between 15 and 20 mmHg, as per requirements of sports socks, was maintained. The effect of materials and structure on the aforementioned responses were examined using analysis of variance statistical analysis. The functional properties are greatly influenced by the material and structure. In this study, the comfort properties are considered to play a major functional role regarding usage by the end user. Its use not only maintained blood circulation by applying external pressure but also defended against unexpected harm or damage of vessels because of high pooling of blood during sports, running, or performance. This study will help to select suitable structure and materials for comfortable SGCS and is expected to fulfill the potential requirements of the athletes.

Optimization of the mechanical and vibrational damping properties of a hybrid rubber particle and glass fibre railway sleeper composite

In the locomotive industry, the railway structural material is frequently subjected to harsh loads and vibration, and the current durability and vibration-resilience capabilities of the sleepers are insufficient. The aim of this paper is to fabricate a railway sleeper composites with enhanced mechanical and vibrational properties. A full factorial experimental design was followed in the composite fabrication with the rubber particles and fibreglass volume fraction ratio varied between 5 and 20% and 5 to 8% respectively. Modelling and optimisation of the mix design was then carried out using numerical modelling techniques. ANOVA tests were carried out to show the model’s accuracy in predicting tensile strength, compression strength, flexural strength, and vibrational damping, as shown by R2 values of 60.69%, 86.60%, 60.05% and 81.41%, respectively. However, the model was not reliable for the composite hardness which had an R2 value of 37.87%. The optimisation model developed in the study indicated that rubber particles of size of 150 μm at volume fraction of 7.48% and fibreglass volume fraction of 8% gave the optimum mechanical and vibrational properties.

Machining efficiency and geometrical accuracy on micro-EDM drilling of titanium alloy

ABSTRACT In the current study, micro-electric discharge drilling (µEDD) is conducted on a titanium grade 2 alloy using a tungsten carbide (WC) tool electrode of 496 µm diameter. Capacitance, voltage, and feed rate are selected as machining variables to conduct the experiments based on the full factorial experimental design method. Overcut, material removal rate (MRR), circularity, and hole taper are considered as performance measures. Furthermore, overall evaluation criteria (OEC) is utilized for multiple-objective optimization by allotting varying and equal weight percentages to each response measure. The results of OECs are compared with a revolutionary heuristic multi-objective genetic algorithm (MOGA), resulting in a similar optimal parametric combination and close response measures are obtained. Micrographic investigation demonstrates that at lower capacitance and voltage levels, there is less burr formation, recast layer, and circularity error. Moreover, FESEM and EDS analyses are employed to investigate the machined surface topology and elemental composition respectively.

Idealized Motherhood on Social Media: Effects of Mothers’ Social Comparison Orientation and Self-Esteem on Motherhood Social Comparisons

ABSTRACT Based on recent findings that mothers make social comparisons to idealized portrayals of motherhood on social media, this study was designed to explore how two individual difference variables (social comparison orientation and self-esteem) affect such social comparison processes. A 2 (social comparison orientation: low vs. high) X 2 (self-esteem: low vs. high) X 2 (idealization of motherhood portrayals: non-ideal vs. ideal) mixed factorial design experiment was conducted among 464 new mothers to test how these individual difference variables moderate the effects of social media motherhood portrayals on the outcomes of state social comparison, perceived parenting competence, and life satisfaction.

Hematite-Gamma Alumina-based Solid Catalyst Development for Biodiesel Production from Palm Oil

This research investigated the performance of hematite-gamma alumina (Fe2O3/γ-Al2O3) catalyst in biodiesel production from palm oil. A full factorial experimental design was utilized to analyze the effect of hematite content, catalyst loading, and methanol-to-oil ratio on catalyst performance. From the experiment, biodiesel in the range of 73.6 to 87.6% FAME content was obtained. It was concluded that the catalyst composition, the methanol-to-oil ratio, and the catalyst loading have a significant effect on the FAME content of the biodiesel. Hematite has strong affinity for fatty acids, so a larger hematite surface area will result in a higher fatty acid absorption capacity. The addition of excess methanol can reduce the contact inhibition between the reactants and the active site of the catalyst, thereby increasing the conversion rate of the reaction. Moreover, a higher amount of catalyst loading can result in an increase in the FAME content when accompanied by an increase in the hematite content of the catalyst.

A Factorial Design Assessment of Marine Exoskeleton-Based Bio-sorption of Relevant Electroplating Metals

A preliminary assessment of the capacity of pulverized crab shells to function as bio-sorbents for the removal of selected metals, zinc, cadmium, and chromium was analyzed according to a factorial experimental design. These metals were chosen because they have little precedent in past sorption studies and represent metals discharged into receiving waters by the electroplating industry. The design was done to assess parameters that have the highest impact on adsorption capacity and removal efficiency. Validation with other heavy metal ion removals was performed for comparison followed by a factorial 33 DOE using JMP®. It was found that for zinc, adsorbent amount, pH, time and the interaction of adsorbent amount*time and pH*adsorbent amount have the highest significance. For cadmium, only adsorbent amount is significant. Finally, chromium uptake was strongly dependent on adsorbent amount and pH. According to ionic radius theory, the favorability for adsorption is according to the following trend: chromium > cadmium > zinc; however, under our set of experimental conditions, the order was: cadmium > zinc > chromium because the presence of calcium carbonate exerts a major role in their sequestration.

The Synergistic Impact of Arbuscular Mycorrhizal Fungi and Compost Tea to Enhance Bacterial Community and Improve Crop Productivity under Saline-Sodic Condition.

Soil salinity has a negative impact on the biochemical properties of soil and on plant growth, particularly in arid and semi-arid regions. Using arbuscular mycorrhizal fungi (Glomus versiform) and foliar spray from compost tea as alleviating treatments, this study aimed to investigate the effects of alleviating salt stress on the growth and development of maize and wheat grown on a saline-sodic soil during the period of 2022/2023. Six treatments were used in the completely randomized factorial design experiment. The treatments included Arbuscular mycorrhizal fungus (AMF0, AMF1) and varied concentrations of compost tea (CT0, CT50, and CT100). AMF colonization, the bacterial community and endosphere in the rhizosphere, respiration rate, growth parameters, and the productivity were all evaluated. The application of AMF and CT, either separately or in combination, effectively mitigated the detrimental effects caused by soil salinity. The combination of AMF and CT proved to be highly efficient in improving the infection rate of AMF, the bacterial community in the rhizosphere and endosphere, growth parameters, and grain yield of maize and wheat. Therefore, it can be proposed that the inoculation of mycorrhizal fungi with compost tea in saline soils is an important strategy for enhancing salt tolerance in maize and wheat plants through improving microbial activity, the infection rate of AMF, and overall maize and wheat productivity.

Investigating the Essential Factors for Thresher Losses and Waste in Peanut Harvester Considering Several Varieties of Crop

Abstract This research investigated the performance of a model traction combine harvester (TCH) for harvesting several varieties of peanuts. The effect of independent factors including tested varieties at three levels (local Moghan, Goli Astana, and Turkish), tractor forward speed (FS) at three levels (4, 5, and 6 km·h−1), and rotational speed (RS) of the thresher at three levels (500, 600, 700 rpm) on losses and wastes were studied and investigated. To analyse the obtained data, a factorial experimental design was used in the form of randomised complete blocks, and Duncan‘s multi-range test was used to compare the mean values. According to the findings, the effects of tractor FS and rotary speed of the thresher on the percentage of threshing losses were significant at the probability level of 1%. Also, the interaction effects of variety type and tractor FS, tractor FS, and rotary speed of the thresher on the percentage of threshing losses were significant at the 1% probability level. Also, the effects of variety type, tractor FS, rotary speed of the thresher, and all mutual effects on the percentage of threshing waste were significant at the 1% probability level. The results of comparing the average effects of the main factors showed that the FS of 6 km·h−1 had the highest average threshing loss (82.89%). Threshing losses were obtained in the Turkish variety with the lowest average value (2.51%) and in the local variety with the highest average value (3.53%).

Peningkatan pH dengan Pemberian Bahan Organik pada Pengelolaan Air Asam Tambang Menggunakan Metode Passive Treatment

Mining is the process of extracting beneficial minerals from the surface of the earth that have an impact on the formation of acid mine drainage (AMD). One method of passive AMD management is passive treatment. This study used the Nested Factorial Experiment Design method. The types of organic matter used were empty fruit bunch oil palm (EFB) and cow dung, with doses of 0 Mg ha-1 (control), 50 Mg ha-1, 100 Mg ha-1, 150 Mg ha-1 and 200 Mg ha-1. Each treatment was three repeats so that 30 units of experimental units were obtained. The pH value of AMD in the untreated (control) reactor was 3.67. The initial reaction (pH) of AMD (0 days) with EFB application at a dose of 50 – 200 Mg ha-1 ranged from 3.63 – 4.28 and the initial pH of cow dung was 3.84 – 4.13. The reaction (pH) of the 1st to 4th weeks of AMD after adding EFB organic matter at a dose of 50 – 200 Mg ha-1 show a pH range (6.38 – 7.59) and cow manure at a dose of 150 – 200 Mg ha-1 show a pH (6.09 – 7.01). The conclusion are that the application of EFB organic matter on constructed wetland media for 4 weeks had a very real effect on increasing the pH of the AMD dose of 100 – 200 Mg ha-1 while cow dung 150 – 200 Mg ha-1 are the most effective against increasing pH.

Effects of Shadow Training and Leg Muscle Strength on Badminton Footwork Agility: A Factorial Experimental Design

As badminton significantly emphasizes player footwork’s agility and precision, performing shadow training and increasing leg muscle strength are believed to increase players’ agility. However, despite recognizing the importance of both training methods in enhancing athletic performance, there is a lack of comprehensive understanding regarding their combined effects on a player's agility during gameplay. This study aimed to analyze group disparities in shadow training while considering varying levels of leg muscle strength and their impact on badminton players' footwork agility. The shadow training groups encompassed those using reaction lights and those under coach direction, while leg muscle strength was categorized as either high or low. Employing an experimental approach with a 2 x 2 factorial design, the study randomly selected 20 students aged 15.3±7.2. Shadow training was conducted in three sessions per week for approximately six weeks. This training focused on rapid/explosive movements. Data on muscle strength and agility were gathered using a leg dynamometer test and a foot exercise test. They were then statistically analyzed using two-way ANOVA at a significance level of 0.05. The results suggest that shadow training with reaction lights is more effective for individuals with high leg muscle strength. Meanwhile, shadow training with a coach’s direction may yield better results for those with low leg muscle strength. However, both training modalities can be beneficial for individuals with low leg muscle strength. These findings provide valuable insights for coaches and badminton instructors in devising tailored training programs to enhance footwork agility. Keywords: Shadow training, reaction lights, the coach's direction, foot work agility, leg muscle strength

Thermo-Mechanical Characterization of Metal-Polymer Friction Stir Composite Joints-A Full Factorial Design of Experiments.

With the increasing demand for lighter, more environmentally friendly, and affordable solutions in the mobility sector, designers and engineers are actively promoting the use of innovative integral dissimilar structures. In this field, friction stir-based technologies offer unique advantages compared with conventional joining technologies, such as mechanical fastening and adhesive bonding, which recently demonstrated promising results. In this study, an aluminum alloy and a glass fiber-reinforced polymer were friction stir joined in an overlap configuration. To assess the main effects, interactions, and influence of processing parameters on the mechanical strength and processing temperature of the fabricated joints, a full factorial design study with three factors and two levels was carried out. The design of experiments resulted in statistical models with excellent fit to the experimental data, enabling a thorough understanding of the influence of rotational speed, travel speed, and tool tilt angle on dissimilar metal-to-polymer friction stir composite joints. The mechanical strength of the composite joints ranged from 1708.1 ± 45.5 N to 3414.2 ± 317.1, while the processing temperature was between 203.6 ± 10.7 °C and 251.5 ± 9.7.

Legacy effects of long‐term autumn leaf litter removal slow decomposition rates and reduce soil carbon in suburban yards

Societal Impact StatementAs cities grow, it is essential to understand how landscape management decisions in urban spaces alter ecosystem function. This study demonstrates that the ubiquitous practice of long‐term leaf litter removal in suburbs, even in relatively small patches of a yard, reduces the soil's ability to cycle nutrients in plant litter and results in lower amounts of carbon stored in the soil. Even two years of retaining leaves where they previously were removed is insufficient to restore decomposition rates or carbon pools. This research is an important step in creating best practices for litter management to maintain essential ecosystem functions, like carbon sequestration, water holding capacity, and soil fertility.Summary Seasonal senesced leaf litter removal eliminates considerable organic material from suburban soils annually. We test if this disturbance alters decomposition and carbon cycles and depletes soils of organic matter over time, creating persistent legacy effects. We used a factorial experimental design to implement 1–2 years of current leaf litter manipulations (remove or retain fallen leaves) within historically raked and unraked areas in suburban Maryland yards. We then compared total organic soil carbon and decomposition using a standardized substrate decomposition methodology (Tea Bag Index) across treatment plots. Long‐term litter removal in suburban yards reduced decomposition rates by 17% and total soil organic carbon concentration by up to 24% compared to areas where leaf litter was retained in situ. In contrast, short‐term management changes (1–2 years) did not significantly impact decomposition rates or total organic soil carbon concentrations. Our findings suggest that long‐term suburban litter raking creates legacy effects that alter decomposition and carbon storage process trajectories that are not easily reversed. This is important in understanding urban ecosystem function and sustainable management.

Development of a Green, Quick, and Efficient Method Based on Ultrasound-Assisted Extraction Followed by HPLC-DAD for the Analysis of Bioactive Glycoalkaloids in Potato Peel Waste.

α-Solanine and α-chaconine are the two most predominant glycoalkaloids (GAs) present in potato. Potato peel contains a high concentration of GAs, which are especially interesting for application in the pharmaceutical industry due to their different beneficial properties (such as anticarcinogenic, anti-inflammatory, antiallergic, antipyretic, antiviral, fungicide, and antibiotic activities, among others); so, potato peel waste can be valorized by extracting these biologically active compounds. For this, a green, quick, and efficient miniaturized analytical approach based on ultrasound-assisted extraction (UAE) combined with HPLC-DAD was developed to quantify α-solanine and α-chaconine in potato peel. Some parameters of the extraction were optimized, including the extraction method, the type of solvent, and the sample/solvent ratio, by a three-factor, three-level (33) full factorial experimental design. The optimal extraction conditions were obtained with UAE using methanol as a solvent and a sample/solvent ratio of 1:10 (w/v, g/mL). The analytical greenness metric for sample preparation (AGREEprep) tool was used to assess the greenness of the methods used. The tool revealed an acceptable green analysis, with 0.61 points. The method was validated and applied to the evaluation of GAs in the peel of 15 commercial varieties of potato. The amount of glycoalkaloids found in the samples evaluated ranged from 143 to 1273 mg/kg and from 117 to 1742 mg/kg dry weight for α-solanine and α-chaconine, respectively. These results reveal the important variability that exists between potato varieties; so, their analysis is of great importance to select the most suitable ones for biovalorization (e.g., the Amandine and Rudolph varieties, with around 3000 mg/kg, in total, of both GAs). To provide higher stability to the peel during storage, freeze-drying or a medium-temperature drying process resulted preferable to avoid GA degradation. Overall, this study will contribute to the expansion of the future biovalorization of potato peel waste as well as provide a powerful analytical tool for GA analysis.

Maximizing the potential of commercial zinc stearate for one-pot esterification and transesterification for high-acidity biodiesel production

Meeting the growing demand for energy while combating the adverse effects of global warming remains challenging today, and biodiesel offers a potential solution to help mitigate the impact of global warming. In this scenario, our primary goal was to optimize biodiesel production from highly acidic soybean oil using a one-pot esterification and transesterification process, addressing the challenges associated with high-acidity substrates. To start, X-ray Diffraction (XRD) guaranteed us just one phase for each commercial catalyst, and we conducted catalytic experiments to select the most suitable Zn-based material for the process, choosing zinc stearate (ZnSt2) as the best candidate. Our study demonstrated that a nano-sized zinc oxide (ZnO) catalyst, which was anticipated to be the most suitable choice, did not exhibit optimal performance. Subsequently, a Full Factorial Design of Experiments (DOE) was employed to optimize reaction parameters, specifically, the reaction temperature and the oil-to-methanol (O:M) molar ratio. The results consistently showed that increased O:M ratio and temperature promoted enhanced fatty acid methyl esters (FAME) production and reduced acidity. Then, experiments were conducted to maximize FAME production and minimize free fatty acid (FFA) content. The results showed that increasing the catalyst concentration from 5 wt% to 10 wt% did not significantly impact FAME production or acidity reduction. Also, while increased methanol should theoretically enhance FAME production and reduce acidity, the results were inconsistent across all experiments. Excess methanol interfered with glycerol separation, leading to decreased FAME yield. Thus, this study underscores the complexity of biodiesel production and highlights the importance of selecting suitable catalysts and optimizing process parameters.