Curvilinear Trajectory Research Articles

Enhancing Maneuverability in a Variable Wheelbase Wheeled Mobile Robot Through Dynamic Steering Curvature Control

ABSTRACTVariable wheelbase wheeled mobile robot (VW‐WMR) is capable of maneuvering flexibly and traversing on rough and soil terrains within confined spaces. While the steering radius of the robot model can be robustly changed by the variable wheelbase length, a challenge is posed in accurately tracking a predefined trajectory through the alteration of wheelbase length. A dynamic steering curvature (DSC) control method is proposed in this work to overcome this challenge, which is achieved by two different approaches utilizing the variable wheelbase length and manipulating drifting motions. First, to enable flexible trajectory adjustments, a 3D Ackermann kinematics model, incorporating the lifting motion of the robot box, is developed to control steering curvature by the changes in wheelbase length. Second, to achieve flexible movement for the inner and outer curves of the originally planned curvilinear trajectory, Ackermann drift models are presented by the establishment of two sequence instantaneous centers. Furthermore, the control performance of DSC is validated through simulation experiments on the ROSTDyn Vortex platform, using a six‐wheeled VW‐WMR named HIT‐MRII robot. The effectiveness of DSC for strategically altering the robot's motion trajectory is demonstrated by the results, which show the relation between the changed trajectory position and the variation in wheelbase length, and the variation in the radii of the instantaneous centers (ICs) in the Ackermann drift model, respectively. In addition, the high maneuverability of the robot using the Ackermann model is proven by physical experiments during steering motions on soil terrain. A comprehensive advantage is demonstrated by the results via Ackermann models, which include shorter runtimes, moderate travel distances, and moderate variations in force on the wheels, compared to different velocity, crabbing motion, and equivalent bicycle models.

A - 5 Longitudinal Analysis of Protective Factors on Cognition Following Total Knee Arthroplasty

Abstract Objective To examine cognitive and brain resilience factors on older adult cognition following total knee arthroplasty (TKA). Methods Participants were recruited through orthopedic clinics and screened for eligibility (i.e., age > 60 years, English as first language, diagnosis of knee osteoarthritis, intact activities of daily living). Data were collected before surgery, three weeks, three months, and one-year post-TKA (N = 67; mean(SD) age = 69.49(7.09) years; mean(SD) education = 15.62(2.83) years; 51% female; 90% non-Hispanic White (NHW), 10% non-Hispanic Black. Participants received baseline magnetic resonance imaging (3 T Siemens Verio). Magnetization-prepared rapid gradient-echo images were preprocessed. Machine learning predicted brain age (DeepBrainNet) was calculated for each participant. Linear mixed effects models examined longitudinal effects of word reading (Wide Range Achievement Test-III (WRAT-III)), brain age gap (predicted brain age minus chronological age), sex, ethnicity/race, pain interference (Brief Pain Inventory), and depression (Beck Depression Inventory-II) on cognitive composites (i.e., memory, working memory/inhibition, reasoning, processing speed, language). Results Memory, working memory/inhibition, reasoning, and processing speed had curvilinear trajectories (p’s < 0.05), declining post-TKA and subsequently returning to baseline. Word reading positively associated with memory (β = 0.065, SE = 0.016, p < 0.001), working memory/inhibition (β = 0.069, SE = 0.016, p < 0.001), reasoning (β = 0.099, SE = 0.021, p < 0.001), and processing speed (β = 0.050, SE = 0.015, p < 0.01). Language negatively associated with BAG (β = −0.041, SE = 0.017, p < 0.05). Women had higher processing speed (β = −0.285, SE = 0.135, p < 0.05), and NHW participants had higher memory (β = 0.479, SE = 0.224, p < 0.05). When pain interference was higher, processing speed (β = −0.003, SE = 0.002, p < 0.05) and language (β = −0.007, SE = 0.002, p < 0.01) were lower. Conclusions Cognitive and brain resilience measures may identify individuals protected against cognitive dysfunction post-surgically. Future research increasing representation in underrepresented groups is warranted.

Hermite Quartic Splines for Smoothing and Sampling a Roughing Curvilinear Spiral Toolpath

From an industrial point of view, the milling of 2.5D cavities is a frequent operation, consuming time and presenting optimization potential, especially through a judicious choice of the tool trajectory. Among the different types of trajectories, some have a general spiral-like aspect and can potentially offer a reduced machining time. They are called curvilinear trajectories and are obtained by interpolation between structure curves, which are the numerical solutions of a partial differential equation. In this case, the machine tool will connect points, and the trajectory will be made up of small segments. While these trajectories exhibit all the necessary qualities on a macroscopic level for rapid tool movement, the tangential discontinuities at a microscopic scale, inherent in the discretization, significantly increase the machining time. This article proposes a method to reparameterize the structure curves of the curvilinear spiral with a set of C2 connected Hermit quartic spline patches. This creates a smooth toolpath that can be machined at an average feedrate closer to the programmed one and will, de facto, reduce the machining time. This article shows that the proposed method increases on two representative geometries of cavities and toolpath quality indicators, and reduces the milling time from 10% to 18% as compared to the PDE curvilinear spiral generation method proposed by Bieterman and Sandström. In addition, the proposed method is suitable for any non-convex pocket, with or without island(s).

Association Between Persistent Hypothermia After Cardiopulmonary Bypass in Neonates and Odds of Serious Complications.

Persistent hypothermia after cardiopulmonary bypass (CPB) in neonates with congenital heart defects (CHD) has been historically considered benign despite lack of evidence on its prognostic significance. Examine associations between the magnitude and pattern of unintentional postoperative hypothermia and odds of complications in neonates with CHD undergoing CPB. Retrospective cohort study. Single northeastern U.S., urban pediatric quaternary care center with an established cardiac surgery program. Population-based sample of neonates greater than or equal to 34 weeks gestation undergoing their first CPB between 2015 and 2019. None. Hourly temperature measurements for the first 48 postoperative hours were extracted from inpatient medical records, and clinical characteristics and outcomes were accessed through the local patient registry. Group-based trajectory modeling (GBTM) identified latent temporal temperature trajectories. Associations of trajectories with outcomes were assessed using multivariable binary logistic regression. Outcomes (postoperative complications) were manually adjudicated by experts or were predefined by the patient registry. Four hundred fifty neonates met inclusion criteria. Their mean (sd) gestational age was 38 weeks (1.3), mean (sd) birth weight was 3.19 kilograms (0.55), median (interquartile range) surgical age was 4.7 days (3.3-7.0), 284 of 450 (63%) were male, and 272 of 450 (60%) were White. GBTM identified three distinct curvilinear temperature trajectories: persistent hypothermia (n = 38, 9%), resolving hypothermia (n = 233, 52%), and normothermia (n = 179, 40%). Compared with the normothermic group, those with persistent hypothermia had significantly higher odds of cardiac arrest, actionable arrhythmia, delayed first successful extubation, prolonged cardiac ICU length of stay, very poor weight gain, and 30-day hospital mortality. The persistent hypothermia group was characterized by greater odds of having a lower gestational age, more prevalent neurologic abnormalities, more unplanned reoperations, and a low surgical mortality risk assessment. Persistent postoperative hypothermia in neonates after CPB is independently associated with having greater odds of complications. Recovery patterns from postoperative hypothermia may be a clinically useful marker to identify patient instability in neonates. Additional research is needed for causal modeling and prospective validation before clinical adoption.

Proposing a Bayesian hierarchical growth curve model (BHGCM) for tourism and hospitality research

Curvilinear growth trajectories of products/services are common in the tourism and hospitality industry. To fit nonlinear growth patterns with multilevel structures, this study proposed Bayesian hierarchical growth curve models (BHGCMs) in line with the increasing adoption of Bayesian analysis in tourism and hospitality academia. We provided the basic form of BHGCM along with its unique advantages. For an empirical test, this study applied several growth curves to approximate online reviews of U.S. hotels from August 2020 to January 2021. After selecting a Gompertz curve as a mean function of the GCM, a Bayesian hierarchical approach was employed to estimate growth parameters—namely, base and maximum volume of hotel reviews, inflection week, and relative growth rate—and identify their determinants. Our findings demonstrate the superiority of the proposed BHGCM in fitting the growth patterns of hotel reviews while revealing the effect of price and accumulated reviews on the parameters.

Tennis. Analytics when applying the most powerful shot

Actuality. Many coaches mistakenly assume that the flight of the ball on a straight line trajectory with a flat feed and impact will hit the tennis net. As a result, it is considered that adolescents do not need to teach a flat serve, but to teach immediately spin serve with the rotation of the ball.
 Purpose of the article: to show analytical and theoretical researches of flat shots in tennis their ability for the best application.
 Methodology. Integration of knowledge of various sciences and their methods to solve the problems of physical education and sports training.
 Scientific novelty. An analytical method over of calculation of descriptions of motion is brought by means of kinematics. Factors affecting the trajectory of the ball's flight have been educed. The analytical dependence of the instantaneous and final speed, range and altitude of the ball on the mechanical parameters without taking into account the air resistance is derived. The analytical analysis of these shots is expounded with initial velocity, depending on the angle of slope to horizon under that there is a blow to the ball in the distance h from the plane of court. Correcting coefficients over are brought. A percent on that actual speed can change in a flat blow and serve is given. The advantages and disadvantages of these strikes are given. The terms of implementation of flat serve, her advantages and defects, are examined.
 Conclusions. Most powerful and at the same time most difficult for implementation flat shots at that a ball is not given by a rotation are considered. It is necessary to take into account that rectilineal and curvilinear trajectories outbowed only in a vertical plane are named flat. A trajectory of flight of the ball sent by a player can be different. The decisive influence on it is the rotation of the ball during its flight. The rotation of the ball during its flight has a decisive influence on it. Factors affecting the trajectory of the ball's flight have been clarified.

Sexual (Double) Standards Revisited: Similarities and Differences in the Societal Evaluation of Male and Female Sexuality

Past research has been inconclusive regarding the continued existence of the sexual double standard (SDS)—that is, differential expectations and evaluations of sexual activity for men (rewarded for sexual activity) and women (punished for sexual activity). Here, we present the similarities and differences (S&D) model of sexual standards, which significantly qualifies the traditional SDS by highlighting both similarities and differences between standards applied to women and men. Across two samples (student/community sample, crowdsourcing sample; Ntotal = 342) and seven sexual outcomes, high sexual activity was rated more favorably in men than in women (replicating previous research), and the opposite was true for low sexual activity (extending previous research). Importantly, moderate (not extremely low or high) sexual activity was rated most favorably in both genders, suggesting similar and curvilinear intragender trajectories. These findings illustrate a distinctly different perspective on male and female sexuality and open avenues for new research.

Models of Cutting Forces in the Matrix Theory of Multitool Machining Accuracy

Two generalized cutting schemes predetermining the machining error formation mechanism are distinguished: contour machining, when the profile of the machined surface is formed by the corresponding tool path - contour machining; profile machining, when the profile of the machined surface is formed by the corresponding tool profile - shaped tool machining. For the trajectory scheme, the known force relations are generalized to a spatial curvilinear trajectory. Generalized dependencies for the cutting force components of form, slotted, cut-off and groove cutters are derived for the profile scheme. The evaluation of the adequacy of the proposed model for cutting force components is carried out on the basis of a specially conducted experimental research of the profile turning process with direct measurement of forces at different levels of varying technological factors. Thus, the developed dependences of the coordinate components of cutting forces on technological factors (parameters of cutting conditions, strength properties of the processed material, deformation properties of the technological system, etc.) allow using them for the practical application of machining error models in the matrix theory of multitool machining accuracy.

Curvilinear Approach to Landing

ABSTRACT The article describes the problem of controlling an aircraft control when performing a landing on a curvilinear trajectory. The adoption of a curvilinear approach trajectory allows reducing the impact of air traffic on the areas adjacent to the airport. Performing the correct approach on the curvilinear path requires support. For the correct execution of the landing manoeuvre on the curvilinear track, it is necessary to establish reference points so that the repeatability of the manoeuvre is ensured, especially in the case of landing more than one aircraft at the same time. In the following parts, the landing control system is presented. Particularly carefully presented is the issue of performing tests of the designed control system, which in the case of the aircraft control system during the approach to landing must be extremely thoroughly verified. The test plan included both verification the correctness of the adopted control laws and their robustness to interference occurring as a result of atmospheric air streams.

Algorithm for controlling a spherical robot with a pendulum actuator in the problem of pursuing and hitting a moving target

An algorithm is developed to control a spherical robot with a pendulum actuator through servoconstraints, generating the necessary control torque. Servoconstraints set a movement program that allows the robot to pursue a moving target until it is hit. The rectilinear and curvilinear trajectories of the robot, constructed on the basis of numerical integration, are considered, their length and time to hit the target are determined. Keywords:spherical robot, pendulum actuator, control, pursuit, hit, nonholonomic constraint, servoconstraint evaeva_84@mail.ru

Distinguishing Trajectories and Drivers of Vegetated Ecosystems in China's Loess Plateau

AbstractTerrestrial ecosystems can exhibit various behaviors in response to climate change and human activities. Nonlinear and abrupt shifts in ecosystems are particularly important as they indicate substantial modifications in ecosystem structure and function, posing a threat to the provision of ecosystem services. Here we distinguish between linear, curvilinear, and abrupt shifts in ecosystem productivity from 2000 to 2020 in China's Loess Plateau. We utilize spatial Random Forest models to analyze the driving factors behind these change patterns. Our findings indicate that 84.1% of the ecosystems experienced a positive change in plant productivity, while a small proportion (2.5%) exhibited a negative change. Abrupt shifts are prevalent in both positive and negative changes in ecosystem productivity, with negative changes often manifesting as abrupt shifts (79.3%). Negative changes in plant productivity, particularly the negative abrupt shifts, are primarily associated with human activities characterized by increased nighttime light and urbanization. Land conversion to forest is linked to a curvilinear trajectory in plant productivity, characterized by nonlinear changes with acceleration. Higher water availability and a wetter environment are more likely to promote positive changes in plant productivity. Moderate warming trends contribute to abrupt positive changes in plant productivity, while high warming trends are associated with increased negative abrupt and curvilinear changes. We highlight the importance of accounting for diverse change behaviors in ecosystems for the development of targeted conservation and restoration measures.

Trajectories of Competitive Employment of Autistic Adults through Late Midlife.

Autistic adults experience challenges in maintaining employment; however, little is known about patterns of competitive employment through late midlife. This longitudinal study examined the change in hours of competitive employment for a cohort of autistic adults over a 22-year period. The study's aims were to provide a fine-grained analysis of competitive employment patterns, to determine whether there was age-related change, and to test whether trajectories differed between those with and without intellectual disability (ID). Using an accelerated longitudinal design, trajectories of hours of competitive employment were estimated from young adulthood through late midlife in a community-based cohort (n = 341; 1327 observations). Results indicated a significant curvilinear trajectory of age-related change in hours of competitive employment, with differences between those with and without ID. For those without ID, the number of competitive employment hours increased from young adulthood until early midlife, then leveled off and decreased into late midlife. For those with ID, engagement in competitive employment was low throughout. Although competitive employment is just one option for vocational engagement, it is a goal often articulated by autistic adults who seek entry into the general workforce. The present research reveals their degree of engagement in the competitive workforce across the decades of adulthood.

Microphone array based on tangent line method.

The tangent line method (TLM) was originally proposed for loudspeaker arrays to generate curvilinear acoustic beams. In this study, the TLM was applied to a microphone array. Based on reciprocity, the TLM-based microphone array can be used to form curvilinear beams. A curvilinear beam is produced as an envelope for the tangent lines. Tangent lines, which are straight beams with different angles, are generated by applying a delay-and-sum (DAS) beamformer. Because the envelope length is specified, the distance discrimination in the sensitivity is better using the TLM than the DAS beamformer. Case studies have indicated that directivity is better in the former TLM than in the latter. The TLM is realizable with fixed delay times for each microphone unless the formation of curvilinear trajectory is altered according to reproduction frequencies. Hence, the same simplicity of implementing the DAS beamformer can be achieved by optimizing the curvilinear trajectory based average frequency. Optimization is conducted such that the acoustic contrast between the focal point and elsewhere is maximized. In summary, the frequency-averaged optimal TLM can be a fixed beamformer with better performance than and the same simplicity as the DAS beamformer.

Mathematical models of coordinated group pursuit with autonomous defenders’ control

This paper considers a computer model of a quasi-discrete group pursuit game. In which there are pursuers, targets, and defenders. In the models of the paper, the goal of the pursuers is to reach static goals. It is possible for more than one pursuer to reach a goal at different times. The goal of the defenders is to defeat the pursuers. A victory for the defenders is the defeat of all targets. For the defenders, the number of pursuers is uncertain. In the paper model, a uniform detection environment of pursuers is formed. The uniform detection environment is the result of set-theoretic operations on points in space. In the paper models, the uniform detection environment is a single connected numerous. A pursuer is considered detected if it enters the given area. As a variant of the optimization factor, the defender for a pursuer can be selected based on the minimum distance to the pursuer. The paper also considers variants of defender localization at a single point. Additional algorithms of the above models are developed that take into account the constraints of defenders at a single location. The difference of algorithms in case of presence or absence of information for defenders about the number of pursuers, their targets, etc. is considered. The results obtained in the paper can be demanded by the developers of robot complexes with autonomous control. Under the coordinated behavior of pursuers in the paper we consider following projected curvilinear trajectories from the locations of pursuers with timed launch to solve the following objectives: the task of simultaneously reaching static targets, the task of simultaneously entering the detection area. The paper does not consider the problems of automatic evasion of pursuers from defenders and from collisions with other pursuers.

Child-level factors associated with Spanish-English bilingual toddlers' productive vocabulary growth.

This longitudinal study-conducted in the Midwestern United States-examines the child-level factors that promote Spanish-English bilingual toddlers' (n = 47; Mage = 18.80 months; SDage = 0.57) productive vocabulary skills from 18 to 30 months of age. At 6-month intervals, caregivers reported on toddlers' Spanish and English words produced as well as their language exposure at home. Video recordings at child age 18 months yielded estimates of toddlers' speech output (word tokens per minute). In addition, at child age 18 months, caregivers reported on toddlers' linguistic skills (comprehension), demographic background (gender, household income), and nonverbal behaviors (gesture production). Results showed that toddlers were exposed to both English and Spanish and received more Spanish than English from primary caregivers; there were no significant primary caregiver input differences across time. Growth modeling revealed linear growth rates for Spanish and conceptual (Spanish, English combined) vocabulary and a curvilinear trajectory for English vocabulary. Furthermore, toddlers' Spanish and conceptual vocabularies were positively associated with their higher frequencies of token use, greater production of gesture, and greater comprehension skills, even after controlling for input. Moreover, Spanish and conceptual growth rates were positively associated with higher token use. In terms of English, toddlers' vocabulary at child age 18 months was positively associated with their comprehension skills. Toddlers' use of more gestures and tokens as well as gender (boys) influenced their English acceleration rates over time. Findings indicate that unique trajectories exist for each of a bilingual's languages and these trajectories are differentially influenced by child-level factors, including their speech output, not only exposure to language. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The influence of early-life adversity on the coupling of structural and functional brain connectivity across childhood

Early-life adversity (ELA) exposure is suggested to accelerate development. However, the influence of ELA on neurodevelopmental trajectories has not been assessed directly but largely inferred from retrospective reporting in adult cohorts. Using multimodal neuroimaging data from a pediatric cohort study (N = 549), we modeled neurodevelopmental trajectories over childhood with structure–function coupling (SC–FC), the correlation between structural and functional connectivity. A linear decrease in SC–FC was observed from age 4.5 to 7.5 years. When stratified by ELA, only the high-adversity group showed a curvilinear trajectory, with a steep decrease between age 4.5 and 6 years, suggestive of accelerated neurodevelopment. This finding was confirmed by increased DNA-derived epigenetic age acceleration at age 6 years in the high- relative to low-adversity groups. SC–FC at age 4.5 years also positively moderated the associations between ELA and behavioral outcomes assessed in mid-childhood. These results demonstrate the association between ELA and neurodevelopment, and how they interact to influence behavior.

Vertical Ground Reaction Forces in Parkinson's Disease: A Speed-Matched Comparative Analysis with Healthy Subjects.

This study aimed to investigate and compare the vertical Ground Reaction Forces (vGRFs) of patients with Parkinson's Disease (PwPD) and healthy subjects (HS) when the confounding effect of walking speed was absent. Therefore, eighteen PwPD and eighteen age- and linear walking speed-matched HS were recruited. Using plantar pressure insoles, participants walked along linear and curvilinear paths at self-selected speeds. Interestingly, PwPD exhibited similar walking speed to HS during curvilinear trajectories (p = 0.48) and similar vGRF during both linear and curvilinear paths. In both groups, vGRF at initial contact and terminal stance was higher during linear walking, while vGRF at mid-stance was higher in curvilinear trajectories. Similarly, the time to peak vGRF at each phase showed no significant group differences. The vGRF timing variability was different between the two groups, particularly at terminal stance (p < 0.001). In conclusion, PwPD and HS showed similar modifications in vGRF and a similar reduction in gait speed during curvilinear paths when matched for linear walking speed. This emphasized the importance of considering walking speed when assessing gait dynamics in PwPD. This study also suggests the possibility of the variability of specific temporal measures in differentiating the gait patterns of PwPD versus those of HS, even in the early stages of the disease.

Obstacles shape the way we walk at home

IntroductionWalking indoors, particularly at home, presents a distinct experience compared to the conventional pedestrian walking classically described. Our homes encompass intricate, confined, and cluttered architectural spaces that necessitate a predominantly curvilinear walking pattern. Despite the growing interest in studying our home, spurred by successive COVID-19 lockdowns, there remains a dearth of information regarding our walking behaviors inside homes, yet rich in data on the physical and sensory links between humans and their daily interior environment.MethodsThis study presents the outcomes of a controlled experiment conducted in an apartment in Montpellier, France. Participants were tasked with traversing the living room at a natural pace, encountering two natural obstacles-a large dining table and a small coffee table. They then walked back in opposite direction, circumnavigating the same two obstacles. To examine walking behavior within a pseudo-natural context, three conditions were tested: a controlled condition and two conditions that perturbed the natural curvilinear trajectory perceptually, by imposing an unpleasant sound, or physically, by suddenly displacing the coffee table between conditions. Twenty participants performed 30 trials in each condition. We approximated the position of their center of mass and computed various metrics related to their trajectories, including walking speed, obstacle clearance distance, its adaptation over time, and inter-trial trajectory variability.ResultsFindings revealed a greater visual clearance distance for the dining table compared to the coffee table, a difference reduced by the perturbation caused by displacing the coffee table. This clearing distance diminished with repetitions, showing that over time we tend to walk closer to obstacles around us. These adaptations were clearly the result of an active visuo-motor regulation, as evidenced by the reduced trajectory variability at, or just before, the location of the obstacles.DiscussionCollectively, these results demonstrate that walking at home is a flexible behavior necessitating continuous perceptual adaptations in our daily trajectories. These findings could contribute to a detailed analysis of walking indoors under natural conditions, and the investigated metrics could serve as a baseline for comparing the embodiment of physical and mental health in walking patterns, for instance during lockdowns. Furthermore, our findings have consequences for safer mediated human architecture interaction.

58 Parent Ratings of Internalizing and Externalizing Behaviors in Children with NF1 Across Childhood: A Longitudinal Investigation

Objective:The purpose of the present study is to characterize the trajectory of internalizing and externalizing behaviors in children with NF1 longitudinally from the early childhood period to the school age period on a broad psychosocial norm-referenced measure using linear mixed model growth curves.Participants and Methods:Children with NF1 (n=28) were seen at least once between the ages of 3-8 years old and then again between the ages of 9-13 years old. Parents completed the Behavior Assessment System for Children (BASC) Second Edition; the version of the BASC administered depended on age (i.e., preschool form or child form). Linear mixed model growth curve analyses were used to examine the developmental trajectories of children with NF1 on the following scales, which were selected due to findings in the literature: Externalizing Problems, Internalizing Problems, Hyperactivity, Anxiety, Depression, Attention, and Executive Function. T-scores (M=50, SD=10) were used. Higher scores indicate more challenges.Results:By using loess lines to qualitatively describe the patterns of ratings across time, it is evident that most scales (Externalizing Problems, Internalizing Problems, Hyperactivity, Attention Problems, Executive Function) demonstrated curvilinear trajectory patterns, with scores peaking in the 8-10-year-old range, then decreasing again. However, there was no statistically significant effect of age on any of the scales. Notably, trajectories largely included standard scores within the normative range (T-scores between 45-55).Conclusions:Overall, the models also suggest that most children with NF1 are within the average range of functioning on all scales examined across the childhood period. Furthermore, with the exception of the Depression and Anxiety scales, ratings tend to peak around the 8-10-year period, and then decrease into early adolescence. Thus, when working with patients with NF1, it may be the case that clinicians note relative increases in challenges across these domains in late childhood, though these challenges may decrease over time during this age range. Linear growth curve modeling identified that the developmental trajectories of internalizing and externalizing behaviors of children with NF1, as rated by parents, remain stable across the childhood period. Importantly, low power may have contributed to the lack of observed age effects. Longitudinal research would be beneficial to capture patterns that may emerge in adolescence or adulthood.

Effects of vitamins C and E in tris citric acid glucose extender on chilled semen quality of Kail ram during different storage times

Mammalian sperm cells are highly vulnerable to lipid peroxidation by free radicals. Antioxidants such as vitamin E, and vitamin C neutralize the activity of free radicals and protect the sperm from reactive oxygen species. The present study was conducted to investigate the effects of vitamin C, vitamin E, and their combination in a Tris-based extender on the semen quality of Kail Ram. Semen samples from five mature Kail rams were collected in this study. The semen samples were diluted by Tris-glucose-egg yolk. Diluted semen samples were divided into four parts. The first part was added with 1 mg/ml of vitamin C, the second part was added with 1 mg/ml of vitamin E and the third part was added with both vitamin C and E, in combination with a dose of 1 mg/ml. The fourth part was considered as control without any addition. The diluted semen samples were cooled gradually and preserved at 5˚C for three days. Sperms in chilled diluted semen samples were examined for motility, viability, and plasma membrane integrity every 24 h for three days (72 h). Present study results showed significant (P < 0.05) effects of vitamins C, E, and their combination on some parameters such as motility, straightness of average special path, linearity of the curvilinear trajectory, and beat-cross frequency. However, there was no significant (P < 0.05) effect of storage duration and antioxidants (vitamin C, E, and their combination) on viability, sperm plasma membrane integrity, and some CASA parameters. From the present study, it could be concluded that the supplementation of vitamins C, and E, and their combination do not enhance the life span and quality of semen in Kail ram during liquid storage at 5 °C.