Variation In Behavior Research Articles

Comparison of Butorphanol-Azaperone-Medetomidine and Nalbuphine-Medetomidine-Azaperone for Immobilization of White-Tailed Deer (Odocoileus virginianus).

Butorphanol-azaperone-medetomidine (BAM) is commonly used for white-tailed deer (Odocoileus virginianus) immobilization in captive and free-ranging populations. It is a federally regulated controlled substance requiring stringent regulatory compliance, complicating field application. A prescription-only drug combination, nalbuphine-medetomidine-azaperone® (NalMed-A) provides a less-regulated alternative for use by wildlife professionals. Efficacy and safety of these drug combinations for immobilization of deer have not been compared in a controlled trial, and reports of dose-specific effects of NalMed-A on white-tailed deer physiology are lacking. Additionally, residual effects of these drugs on deer behavior, food consumption, and stress response have not been reported. In February through April 2021, we immobilized 30 captive female, adult white-tailed deer in three treatment groups (n=10 each). Hand-injected doses were 1.5 mL BAM intramuscularly (IM; 41.0 mg butorphanol, 13.6 mg azaperone, 16.4 mg medetomidine), 1.5 mL NalMed-A IM (60.0 mg nalbuphine, 15.0 mg medetomidine, 15.0 mg azaperone), and 2.0 mL NalMed-A IM (80.0 mg nalbuphine, 20.0 mg medetomidine, 20.0 mg azaperone). We compared quality of immobilizations and reversals and times to induction and reversal among treatments, collected biological samples to measure stress hormones and blood gases, and conducted observations to determine treatment-related variations in behaviors. When an effective dose was administered, both BAM and NalMed-A produced rapid and smooth immobilization and recovery after reversal. All treatments in combination with manual restraint caused some degree of hyperthermia, hypoxemia, hypercarbia, bradycardia, respiratory and metabolic acidosis, and elevated lactate and serum cortisol. At 60 d, all deer were still alive, with no apparent residual effects. Vital signs of deer exposed to manual restraint and these drug combinations should be monitored closely, with supportive therapy provided when needed. We suggest BAM and NalMed-A are safe for immobilizing deer in situations similar to our trials, although doses may perform differently in deer remotely injected without manual restraint.

Hubungan Kontrol Diri dan Gaya Hidup Hedonis dengan Perilaku Konsumtif Terhadap Produk Fashion Pada Mahasiswa Laki-Laki Di Yogyakarta

This study aims to analyze the relation of self-control and hedonistic lifestyle on the consumptive behavior of male students in Yogyakarta, with a specific focus on expenditures for fashion products. A quantitative approach was employed, involving 103 respondents. The findings reveal that students allocate up to 50% of their allowance to fashion, influenced by trends and advertisements, despite the majority exhibiting high levels of self-control. Regression analysis indicates that self-control negatively affects consumptive behavior, while hedonistic lifestyle positively influences it. The coefficient of determination (R²) shows that 61.6% of the variation in consumptive behavior can be explained by these two variables. These results underscore the importance of self-control in managing expenditures and highlight the negative impact of a hedonistic lifestyle on consumptive behavior. This research is expected to provide deeper insights into the relationship between self-control, hedonistic lifestyle, and consumptive behavior among students, serving as a reference for more prudent financial management.

Yes, they're all individuals: Hierarchical models for repeat survey data improve estimates of tree growth and size

Abstract Repeat measurement surveys of tree size are used in forests to estimate growth behaviour, biomass and population dynamics. Although size is measured with error and individuals vary in their growth trajectories, current size‐based growth modelling approaches do not usually or fully account for both of these features, and therefore under‐utilise available data. We present a new method that leverages the auto‐correlation structure of repeat surveys into a hierarchical Bayesian longitudinal growth model. This new structure allows users to correct for measurement error and capture individual‐level variation in growth trajectories and parameters. To demonstrate the new method we applied it to a sample of tropical tree survey data from long‐term monitoring sites at Barro Colorado Island. We were able to reduce estimated error in size and growth, and extract individual‐ and population‐level growth parameter estimates. We used simulation to evaluate the ability of the new method to improve estimates of growth rate and size, and estimate individual and species‐level parameters. Our method substantially improved the root mean squared error (RMSE) for growth by an average of 61% compared to existing approaches using pairwise differences and reduced RMSE in estimated size RMSE compared to ‘observed’ values in simulated data. Better numerical integration methods (Runge–Kutta fourth order in comparison to Euler and midpoint) provided better estimates of parameters, but did not improve the estimation of size and growth. The choice of a positive growth function eliminated all negative increments without data exclusion. Overall, this study shows how we can gain new and improved insights on growth, using repeat forest surveys. Our new method offers improved biomass dynamics estimation through reduced error in sizes over time, coupled with novel information about within‐species variation in growth behaviour that is inaccessible with species average models, such as individual parameters for the growth function which allows for relationships between parameters to be considered for the first time.

Emergent collective behavior evolves more rapidly than individual behavior among acorn ant species

Emergence is a fundamental concept in biology and other disciplines, but whether emergent phenotypes evolve similarly to nonemergent phenotypes is unclear. The hypothesized process of emergent evolution posits that evolutionary change in at least some collective behaviors will differ from evolutionary change in the corresponding intrinsic behaviors of isolated individuals. As a result, collective behavior might evolve more rapidly and diversify more between populations compared to individual behavior. To test whether collective behavior evolves emergently, we conducted a large comparative study using 22 ant species and gathered over 1,500 behavioral rhythm time series from hundreds of colonies and isolated individuals, totaling over 1.5 y of behavioral data. We show that analogous traits measured at individual and collective levels exhibit distinct evolutionary patterns. The estimated rates of phenotypic evolution for the rhythmicity of activity in ant colonies were faster than the evolutionary rates of the same behavior measured in isolated individual ants, and total variation across species in collective behavior was higher than variation in individual behavior. We hypothesize that more rapid evolution and higher variation is a widespread feature of emergent phenotypes relative to lower-level phenotypes across complex biological systems.

Local stress/strain field analysis of die-casting Al alloys via 3D model simulation with realistic defect distribution and RVE modelling

The deformation and fracture behavior of die-casting aluminium (Al) alloys is very complex. Due to local variations in properties, the microstructure and mechanical behavior of materials are highly anisotropic. In this paper, an attempt has been made to quantitatively study the defect characteristics of high pressure cast Al alloy parts using experimental and finite element calculation methods, and to analysis the effect of local porosity and pore size on plasticity. Three-dimensional solids with real defect distribution are obtained by using 3D X-ray computed tomography, and used as an input for building a finite element model. The damage initiation of cast Al alloys under complex stress states is analyzed from micro to macro scales. Crack propagation occurs through two modes of microporous agglomeration: aggregated pores produce cracks from internal necking and stress concentration. Then, they expand in the same direction, agglomerate in a specific direction and eventually fracture. Subsequently, the effect of porosity on non-homogeneity was elucidated by obtaining local stress/strain behavior through digital image correlation measurements. Additionally, a theoretical framework of elasto-plastic deformation of microstructures and a 3D representative volume element model are developed to simulate the deformation and damage processes under cyclic boundary conditions of materials. The simulation results show that the local stress/strain around the pores evolves gradually with deformation. During the die casting process, the method demonstrates the ability to predict the mechanical behavior of Al alloys.

Smaller and bolder fish enhance ecosystem-scale primary production around artificial reefs in seagrass beds.

Effective management of wild animals requires understanding how predation and harvest alter the composition of populations. These top-down processes can alter consumer body size and behavior and thus should also have consequences for bottom-up processes because (1) body size is a critical determinant of the amount of nutrients excreted and (2) variation in foraging behavior, which is strongly influenced by predation, can determine the amount and spatial distribution of nutrients. Changes to either are known to affect ecosystem-scale nutrient dynamics, but the consequences of these dynamics on ecosystem processes are poorly understood. We used an individual-based model of an artificial reef (AR) and reef fish in a subtropical seagrass bed to test how fish body size can interact with variation in foraging behavior at the population and individual levels to affect seagrass production in a nutrient-limited system. Seagrass production dynamics can be driven by both belowground (BGPP) and aboveground primary production (AGPP); thus, we quantified ecosystem-scale production via these different mechanistic pathways. We found that (1) populations of small fish generated greater total primary production (TLPP = BGPP + AGPP) than large fish, (2) fish that foraged more increased TLPP more than those that spent time sheltering on ARs, and (3) small fish that foraged more led to greatest increases in TLPP. The mechanism by which this occurred was primarily through increased BGPP, highlighting the importance of cryptic belowground dynamics in seagrass ecosystems. Populations of extremely bold individuals (i.e., foraged significantly more) slightly increased TLPP but strongly affected the distribution of production, whereby bold individuals increased BGPP, while populations of shy individuals increased AGPP. Taken together, these results provide a link between consumer body size, variation in consumer behavior, and primary production-which, in turn, will support secondary production for fisheries. Our study suggests that human-induced changes-such as fishing-that alter consumer body size and behavior will fundamentally change ecosystem-scale production dynamics. Understanding the ecosystem effects of harvest on consumer populations is critical for ecosystem-based management, including the development of ARs for fisheries.

Oxidation effects on the optical and electrical properties of MoS2 under controlled baking temperatures

As silicon-based semiconductor technology scales down to the nanoscale, it encounters significant physical limitations, including reduced electron mobility, short-channel effects, and increased heat generation, which hinder device performance and reliability. Two-dimensional (2D) semiconductors, such as molybdenum disulfide (MoS2), offer great potential with superior electrical properties at the nanoscale, but the issue of excessive heat generation in highly integrated circuits persists. Therefore, it is essential to investigate the thermal durability of MoS2 under various heating conditions and its impact on physical properties and device performance. In this study, we systematically investigated the oxidation behavior and related physical property variations of CVD-grown MoS2 monolayers by baking them at different temperatures. It was clearly revealed that high-temperature baking induces p-doping and structural deformation, significantly altering optical and electrical properties. Despite the degradation in device performance, reduced interfacial Coulomb scattering was observed, suggesting potential for improved device stability. This study underscores the importance of understanding thermal stability to accelerate the development of 2D semiconductors for next-generation electronic devices.

Preparation and characterization of sago/iota-carrageenan microgels as food thickener in texture modified food

An increasing number of older populations with swallowing difficulties need specialized diets with easy-to-chew and safe swallowing characteristics. Texture modification using a thickener is usually used to obtain the desired texture, which helps in lowering the risk of aspiration. Microgels usage to modify the texture and rheology of liquid and pureed foods has been an area of interest in the food industry for many years. Therefore, this study aimed to produce sago starch and ι-carrageenan based microgels with functionality as food thickeners. Different concentrations of ι-carrageenan (25%, 50% and 75%) were added into sago starch dispersion and then fabricated using ultrasound treatment followed by spray drying process. A commercial dysphagia thickener that is normally used at medical institutions and nursing homes was also included as a reference. Microgels with increasing ι-carrageenan concentration showed variation in behaviours during rheological and textural measurements. Rheological tests revealed that sago/ι-carrageenan microgels exhibited a predominant elastic behaviour, with G′>G″ within the frequency range. Texture profile analysis (TPA) suggested that the sample with 2.0 g of sago starch and 2.0 g ι-carrageenan, MS50, produced samples with similar hardness, springiness, and cohesiveness to the reference sample. Overall, sago/ι-carrageenan microgels have shown a potential to be used as an alternative thickener as it provides low adhesiveness and more elastic behaviour which is considered safe-to-swallow food, especially for elderly with swallowing difficulties.

The Core Story: Intertwined Maternal and Progeny Signatures Enclosed in the Otolith

Analytical imaging via synchrotron analysis was used to study sagittal otoliths of four freshwater pipefish species exhibiting amphidromous or freshwater resident lifestyles. We undertook a hyperfine elemental scanning of a 25 μm diameter length area centred on the core, namely the pre-hatch zone, corresponding to the sagitta formed during embryogenesis. We analysed calcium (Ca), strontium (Sr), manganese (Mn), chromium (Cr), cobalt (Co), nickel (Ni) and sulphur (S), with the latter serving to count growth increments. Whatever the species, a Ca pit consistently marked the core; the amphidromous species exhibited Mn enrichment at the core and the sagitta formed a week before hatching. These results illustrate common otolith formation mechanistic processes. Sr and heavy metals’ signals in the pre-hatch zone were compared to their signal in the edge of the otolith, an area encompassing the adult freshwater (adFW) environmental signature. We found that Co and Ni otolith signals had no relation to environmental conditions, but it is worth looking into Cr as a marker of early-life environment. While we caution against the use of a Sr:Ca ratio for life history interpretations at the core because of the Ca pit, the Sr signal analysis uncovered possible variations in the parental behaviour that potentially trigger newly-hatched juvenile migration to sea or residency. Finally, our results demonstrate that the microchemistry of otolith formation during early development is a melting of maternal signal during egg yolk elaboration, of the environmental signal during egg incubation, and of individual physiology during early growth.

Adolescents’ Daily Lives (ADL) project: an intensive longitudinal design study protocol examining the associations between physical literacy, movement behaviours, emotion regulation and mental health

IntroductionAdolescence represents a critical developmental period, with changes in emotional regulation capacities influencing physical and mental health. With less than 6% of Canadian youth currently meeting the 24-hour movement guidelines...

Induction of territorial dominance and subordination behaviors in laboratory mice.

Territorial behaviors comprise a set of coordinated actions and response patterns found across animal species that promote the exclusive access to resources. House mice are highly territorial with a subset of males consistently attacking and chasing competing males to expel them from their territories and performing urine marking behaviors to signal the extent of their territories. Natural variation in territorial behaviors within a mouse colony leads to the formation of dominance hierarchies in which subordinate males can reside within the territory of a dominant male. While the full repertoire of such territorial behaviors and hierarchies has been extensively studied in wild-derived mice in semi-natural enclosures, so far they have not been established in the smaller enclosures and with the genetically-defined laboratory strains required for the application of neural recording and manipulation methods. Here, we present a protocol to rapidly induce an extensive repertoire of territorial behaviors in pairs of laboratory mice in an enclosure compatible with tethered neurocircuit techniques, including a method for the simultaneous tracking of urine marking behavior in mouse pairs. Using this protocol we describe the emergence of robust dominant-subordinate hierarchies between pairs of CD1 outbred or CD1xB6 F1 hybrid mice, but unexpectedly not in C57BL/6 inbred animals. Our behavioral paradigm opens the door for neurocircuit studies of territorial behaviors and social hierarchy in the laboratory.

Dynamic characteristics of commercial Adaptive Cruise Control across driving situations: Response time, string stability, and asymmetric behavior

Adaptive Cruise Control (ACC) is a popular feature for long-distance highway driving due to its convenience. Research has been conducted on the driving characteristics of commercial ACC vehicles that could impact road capacity and congestion. While response time and string stability are major characteristics, previous studies have often overlooked their variations across driving situations. This study analyzes the dynamic characteristics of commercial ACC, including response time, string stability, and asymmetric behavior across different driving situations. A method is proposed to extract the response time of commercial ACC vehicles during cruising, decelerating, and accelerating situations, using cross-correlation and acceleration threshold methods. Phenomena that influence string stability are categorized based on driving situations focusing on their origin and features. This study identifies patterns in asymmetric behavior and presents a car-following model calibration process that incorporates observed features using the OpenACC dataset. The findings reveal distinct variations in response time across different driving situations, escalating in the sequence of deceleration, cruising, and acceleration. String instability during deceleration is influenced by the vehicle’s response time, while during acceleration, it stems from an expanded gap reduction process. ACC vehicles exhibit asymmetric behavior, with a reduced tolerance for gap changes. The Helly model, which integrates response times, asymmetric behavior, and maximum acceleration, accurately simulates vehicle movement and string instability. The observed variations in response time and asymmetric behavior across driving situations provide an understanding of the traffic hysteresis of commercial ACC vehicles. Furthermore, our analysis suggests that achieving string stability requires diverse approaches for each driving situation.

The influence of tax service quality and tax socialization on individual taxpayer compliance in the regional tax office of the Riau Islands

This research investigates how taxpayer compliance at the Riau Islands Regional Tax Office is affected by two factors: the quality of tax services and tax socialization efforts. The researchers surveyed 116 individual taxpayers and analyzed their responses using regression analysis. The findings revealed that both factors positively influenced compliance levels. Specifically, each unit improvement in tax service quality led to a 0.227 unit increase in compliance, while each unit increase in tax socialization resulted in a 0.479 unit rise in compliance. Together, these two factors account for 34.9% of the variations in taxpayer compliance behavior. Based on these results, the study recommends enhancing both service quality and socialization activities to boost tax compliance in the region.

Ardulake temperature profiler: An open-source, low-cost, automated monitoring system to unravel the mixing behavior of lakes

Understanding the thermal classification of lakes based on mixing regimes is fundamental in limnology. Although this classification has traditionally been considered well-established, recent studies highlight variations in the mixing behaviors of ponds and shallow lakes. This paper introduces the Ardulake temperature profiler, an innovative, simple, and autonomous high-frequency temperature monitoring system designed for shallow to moderately deep lakes (3.5 to 10 m). Utilizing Arduino technology and GPRS telemetry, the system is cost-effective, with electronic components and sensors costing approximately USD 250 and buoy construction and deployment around USD 1000. The Ardulake enables real-time environmental temperature monitoring and data storage on an online platform for subsequent analysis and visualization. The collected data supports ecosystem research and the numerical modeling of thermal behavior in lakes. Key strengths of the system include low production and maintenance costs, replicability, and customization capabilities. Challenges, such as interference from animal activity, are addressed with recommended preventive measures tailored to specific fauna. Overall, the Ardulake temperature profiler offers a practical tool for advancing limnological research, with potential for modification to various environmental monitoring objectives.

Personality dimensions in the common octopus (Octopus vulgaris)

Abstract Understanding the origin, universality, and maintenance of among-individual variation in behaviour is a current focus of behavioural ecology and comparative psychology. Research on animal personality emphasising the central role of the individual contributes to conservation efforts and animal welfare by tailoring guidelines and interventions at the individual level. Cephalopods are understudied in this respect, despite being the only invertebrate group currently included in international directives for the protection of animals used for scientific purposes. Here, we assessed among-individual variation in behavioural responses (i.e., animal personality) of 21 common octopuses (Octopus vulgaris) temporarily kept in captivity. We performed a battery of tests across three different experimental contexts, namely a Startle test, a Foraging test, and a Disturbance test, each repeated for four consecutive days, adapting established protocols from other cephalopods. Behavioural variables were moderately repeatable. Results of a principal component analysis revealed a three-component structure, with components we labelled Alertness, Exploration, and Boldness. The components were also moderately repeatable. The components Exploration and Boldness predicted each other across experimental contexts, suggesting a behavioural syndrome. Overall, findings indicate marked individual differences in common octopuses, and provide evidence of personality dimensions in a widely used animal model in neurophysiology and cognition. Our findings thus contribute to the study of the evolution of personality structure from a comparative perspective, and may help individual-level welfare refinement.

Trophic Ecology and Behavioral Pattern of the Vizcachera Owl, Athene cunicularia Molina, 1782 (Strigiformes: Strigidae) in an Urban Environment in Southern Santa Fe province, Argentina

This study investigates the trophic ecology and behavioral patterns of Athene cunicularia in Funes, Santa Fe, Argentina, during 2023-2024. Observations were made of two individuals throughout the four seasons of the year, recording a total of 16 hours of behavior. The results revealed that the owl showed a varied diet composed of 946 prey items identified in 134 pellets, with arthropods as the main source (91.89%). The pellets presented an average size of 31.98 mm and a weight of 1.31 g. Seven behavioral patterns were identified, with rest being the most frequent, especially in autumn and winter. Variations in diet and behavior appear to reflect adaptations to environmental conditions and resource availability, suggesting that the species is opportunistic and generalist. These findings contribute to the understanding of the ecology of A. cunicularia in urban environments, highlighting its role in the local ecological balance.

A unified method to generate representative volume elements with tailored random fibre arrangements to estimate the shear and transverse behaviours of unidirectional continuous fibres composite plies

Axial compressible strength is a key design parameter of CFRP laminate structures, especially for Aerospace where maximum flexure on wings is driven by the global margin of safety on compressive loads. One of its main limiting contributors is the non-linear shear behaviour of the unidirectional ply. This shear response can be predicted by using generated (quasi-)random microstructures set within representative volume elements (RVE). Different microstructures with or without clusters of fibres (resulting from manufacturing processes) are necessary to quantify the mechanical variability. The variability of the microstructures is characterised by the variation of the arrangement, the volume fraction and the misalignment of the fibres. This leads to significant variations in the mechanical performance, in particular for the shear behaviour. In this study, we propose a unified algorithm that makes it possible to generate all the different positions of fibres in microstructures with very high fibre volume fractions. The microstructural parameters responsible for variations in mechanical behaviour are identified to establish a correlation between fibre distribution and the mechanical response. Finally, a composite cross-section is analysed to estimate the local non-linear shear behaviour as well as the compressive strength as an example to illustrate the benefit of complex microstructures modelling.

Personality traits vary in their association with brain activity across situations

Human cognition supports complex behaviour across a range of situations, and traits (e.g. personality) influence how we react in these different contexts. Although viewing traits as situationally grounded is common in social sciences, often studies attempting to link brain activity to human traits examine brain-trait associations in a single task, or, under passive conditions like wakeful rest. These studies, often referred to as brain wide association studies (BWAS) have recently become the subject of controversy because results are often unreliable even with large sample sizes. Although there are important statistical reasons why BWAS yield inconsistent results, we hypothesised that the situation in which brain activity is measured will impact the power in detecting a reliable link to specific traits. We performed a state-space analysis where tasks from the Human Connectome Project (HCP) were organized into a low-dimensional space based on how they activated different large-scale neural systems. We examined how individuals’ observed brain activity across these different contexts related to their personality. We found that for multiple personality traits, stronger associations with brain activity emerge in some tasks than others. These data highlight the importance of context-bound views for understanding how brain activity links to trait variation in human behaviour.

Urban-rural disparity in risky sexual behavior, HIV knowledge, and healthy practices among men who have sex with men: A cross-sectional study in Southeast China.

To identify differences in human immunodeficiency virus (HIV) risky behavior and healthy practices between rural and urban men who have sex with men (MSM) in Southeast China, a cross-sectional study was conducted on MSM aged ≥ 18 years recruited from four community-based organizations (CBOs) in seven cities in Zhejiang Province between October 2022 and March 2023. An electronic survey questionnaire was completed by the study participants to collect HIV risky behavior and healthy practices. The chi-square test and multiple logistic regression were used for analysis. Among the 1,993 MSM participants, 21.1% (420) were rural MSM. Compared with urban MSM, rural MSM was more likely to have a low level of education (high school and below; 46.2% vs. 40.2%, p = 0.028) and a low annual income (≤ 90,000 RMB; 71.2% vs. 64.7%, p = 0.013). Multiple logistic regression showed that, compared with urban MSM in the past 6 months behaviors, rural MSM had lower odds of finding casual sex partners on the Internet (adjusted odds ratio [aOR]: 0.790, 95% confidence interval [CI]: 0.633-0.986), using stimulants with online casual sex partners (aOR: 0.688, 95% CI: 0.506-0.936), and high odds of ever having sex with a female (aOR: 1.460, 95% CI:1.036-2.058). Rural MSM reported lower odds of an HIV knowledge score of 2-3 (aOR: 0.586, 95% CI: 0.454-0.756), HIV testing more than twice (aOR: 0.583, 95% CI: 0.455-0.748), and obtaining four to five types of HIV information (aOR: 0.661, 95% CI: 0.529-0.826), as well as higher odds of high/very high awareness of HIV infection risk (aOR: 2.312, 95% CI: 1.638-3.263), compared to urban MSM. Rural MSM and urban MSM reported discrepancies in HIV risky behavior, HIV knowledge and HIV-related healthy practices. Paying more attention to HIV risky behavior and improving healthy practices in rural areas may help to prevent HIV transmission.

An Exploratory Assessment of Driver Injury Severities in Large-Truck Crashes Involving Fatigued and Non-Fatigued Driving

Fatigue poses a persistent safety challenge for long-haul truck drivers, significantly elevating the risk of highway crashes and compromising daily work performance. This study investigates the factors influencing driver injury severity in single-large truck crashes due to fatigued driving, compared with non-fatigued driving (normal driving). Using Florida crash data from 2011 to 2019 (inclusive), covering both fatigue and non-fatigue-related crashes, this analysis employs random parameters logit models to account for potential unobserved heterogeneity in means and variances. A comprehensive array of factors affecting driver injury severity, including spatial and temporal characteristics, vehicle and traffic attributes, roadway conditions, and driver-specific characteristics, are examined. Strikingly, different parameter estimates emerge for fatigue and non-fatigue-related crashes, indicating fundamental dissimilarities in unobserved heterogeneity in large truck crash data. The estimated model results unveil distinct marginal effects between fatigued and non-fatigued driving, particularly concerning severe injury crashes, suggesting significant variation in driver behavior based on fatigue levels. These findings contribute substantially to the growing literature on the intrinsic disparities between fatigued and non-fatigued driving behaviors. Moreover, this research underscores the potential ramifications of these distinctions on the safety performance of commercial trucks, highway safety technologies, and policy-related safety countermeasures. Understanding the unique characteristics of fatigued driving can inform targeted interventions to bolster safety within the commercial trucking industry and mitigate the impact of severe crashes resulting from fatigued driving.