Comparative Study of Vibration Response in Steel and Braided-Carbon-Fiber Bicycle Handlebars: A Numerical-Experimental Approach with Various Sensors.

The comfort and safety of a cyclist are directly influenced by the vibrational behavior of the handlebar. Hence, the objective of this article is to comparatively assess the vibrational characteristics of two bicycle handlebars: one made of steel and the other made of braided composite material. The transmissibility function represents the relationship between the excitation applied to both handlebars through their stems and the corresponding response in the handle area, which was experimentally obtained by applying a random vibrating signal (constant amplitude of 0.01 g2/Hz) using a shaker. This signal was applied in a frequency range between 100 Hz and 1200 Hz, and the response was measured at one of the two cantilevered ends of the handlebar. Different sensors, including a laser vibrometer and a control accelerometer in the shaker, were utilized. The transmissibility, natural frequencies and damping functions were obtained. Subsequently, another experimental analysis was carried out with the instrumented handlebars mounted on a bicycle, placing three accelerometers and a GPS meter and traveling through a real test circuit, with a rough surface, speed bumps and areas with shaped warning bands. Power Spectral Density (PSD) curves were obtained for the steel and carbon-fiber-composite handlebars in order to quantify the signal intensity. Finally, a fatigue analysis was carried out in order to evaluate the expected life of both handlebars under the experimentally applied load, which is considered the reference cycle. This study offers a comparative analysis of the vibration behavior exhibited by steel and carbon-fiber-composite bicycle handlebars under experimentally applied load. In conclusion, data on natural frequencies, damping functions and fatigue life expectancy for both handlebar materials were obtained. Our study provides valuable insights into the vibrational behavior and performance characteristics of steel and carbon-fiber-composite bicycle handlebars, contributing to the understanding of their comfort and safety implications for cyclists.

Assessment of Public Special Education Teachers Training Needs on Evidence-Based Practice for Students with Autism Spectrum Disorders in Spain.

Over decades, the concern for the quality of psychoeducational practices for students with autism spectrum disorders has led to study to what extent are evidence-based educational methods disseminated among teachers. The purpose of this cross-sectional study, taking as reference Hsiao and Sorensen's previous research, was to identify through a survey to what extent social-communication evidence-based practices for these students were provided in teacher education and in-service training programs, in a sample of 108 special education teachers from Spain, and to compare these results with Hsiao and Sorensen's. Overall, more than 70% of the teachers reported that evidence-based practices in their teacher education programs (87.6%) and in-service training programs (73.6%) were never taught or mentioned incidentally. Finally, a higher percentage of addressing on each practice (i.e., mentioned and discussed or mentioned and taught through direct instruction) is shown in the sample of American teachers compared to the Spaniards, in both training paths.

Multi-Objective Evolutionary Design of an Electric Vehicle Chassis.

An iterative algorithm is proposed for determining the optimal chassis design of an electric vehicle, given a path and a reference time. The proposed algorithm balances the capacity of the battery pack and the dynamic properties of the chassis, seeking to optimize the tradeoff between the mass of the vehicle, its energy consumption, and the travel time. The design variables of the chassis include geometrical and inertial values, as well as the characteristics of the powertrain. The optimization is constrained by the slopes, curves, grip, and posted speeds of the different sections of the track. Particular service constraints are also considered, such as limiting accelerations due to passenger comfort or cargo safety. This methodology is applicable to any vehicle whose route and travel time are known in advance, such as delivery vehicles, buses, and race cars, and has been validated using telemetry data from an internal combustion rear-wheel drive race car designed for hill climb competitions. The implementation of the proposed methodology allows to reduce the weight of the battery pack by up to 20%, compared to traditional design methods.

Isotemporal substitution of inactive time with physical activity and time in bed: cross-sectional associations with cardiometabolic health in the PREDIMED-Plus study.

BACKGROUND: This study explored the association between inactive time and measures of adiposity, clinical parameters, obesity, type 2 diabetes and metabolic syndrome components. It further examined the impact of reallocating inactive time to time in bed, light physical activity (LPA) or moderate-to-vigorous physical activity (MVPA) on cardio-metabolic risk factors, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. METHODS: This is a cross-sectional analysis of baseline data from 2189 Caucasian men and women (age 55-75 years, BMI 27-40 Kg/m2) from the PREDIMED-Plus study (http://www.predimedplus.com/). All participants had ≥3 components of the metabolic syndrome. Inactive time, physical activity and time in bed were objectively determined using triaxial accelerometers GENEActiv during 7 days (ActivInsights Ltd., Kimbolton, United Kingdom). Multiple adjusted linear and logistic regression models were used. Isotemporal substitution regression modelling was performed to assess the relationship of replacing the amount of time spent in one activity for another, on each outcome, including measures of adiposity and body composition, biochemical parameters and blood pressure in older adults. RESULTS: Inactive time was associated with indicators of obesity and the metabolic syndrome. Reallocating 30 min per day of inactive time to 30 min per day of time in bed was associated with lower BMI, waist circumference and glycated hemoglobin (HbA1c) (all p-values < 0.05). Reallocating 30 min per day of inactive time with 30 min per day of LPA or MVPA was associated with lower BMI, waist circumference, total fat, visceral adipose tissue, HbA1c, glucose, triglycerides, and higher body muscle mass and HDL cholesterol (all p-values < 0.05). CONCLUSIONS: Inactive time was associated with a poor cardio-metabolic profile. Isotemporal substitution of inactive time with MVPA and LPA or time in bed could have beneficial impact on cardio-metabolic health. TRIAL REGISTRATION: The trial was registered at the International Standard Randomized Controlled Trial (ISRCTN: http://www.isrctn.com/ISRCTN89898870) with number 89898870 and registration date of 24 July 2014, retrospectively registered.

Lexical effects in word naming in Spanish children

Reading strategies depend on the consistency of the orthographic system. Recently the use of lexical strategies at early stages of reading acquisition has been shown even in transparent orthographies. The aim of this study was to know how different lexical and sublexical variables affect the reaction times (RTs) and articulation times (ATs) in word reading in Spanish children. A group of 46 children of typical reading level in the second and fourth grades of primary school were asked to read aloud 100 words presented on a computer screen. The stimuli were morphologically simple nouns with different ranges of length, frequency, imageability, orthographic neighbors and age of acquisition (AoA). Reading and articulation time were measured. Differences between means of the second and the fourth grade were seen in RTs (p < .001; Cohens' d = 1.41) and ATs (p < 001; Cohen's d = 1.41) in a t-test. Analyses of mixed-effects revealed that word length, a sublexical variable, and frequency and AoA, lexical variables, affected both grades, mainly on the RTs. The presence of lexical variables reducing RTs and ATs in second grade suggests that lexical reading is present from very early stages in Spanish children (AU)

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Lexical effects in word naming in spanish children.

Reading strategies depend on the consistency of the orthographic system. Recently the use of lexical strategies at early stages of reading acquisition has been shown even in transparent orthographies. The aim of this study was to know how different lexical and sublexical variables affect the reaction times (RTs) and articulation times (ATs) in word reading in Spanish children. A group of 46 children of typical reading level in the second and fourth grades of primary school were asked to read aloud 100 words presented on a computer screen. The stimuli were morphologically simple nouns with different ranges of length, frequency, imageability, orthographic neighbors and age of acquisition (AoA). Reading and articulation time were measured. Differences between means of the second and the fourth grade were seen in RTs (p < .001; Cohens' d = 1.41) and ATs (p < 001;Cohen's d = 1.41) in a t-test. Analyses of mixed-effects revealed that word length, a sublexical variable, and frequency and AoA, lexical variables, affected both grades, mainly on the RTs. The presence of lexical variables reducing RTs and ATs in second grade suggests that lexical reading is present from very early stages in Spanish children.