Search results for "force"
showing 10 items of 3423 documents
Developments in the biomechanics and equipment of Olympic cross-country skiers
2018
Source at: http://doi.org/10.3389/fphys.2018.00976 Here, our aim was to describe the major changes in cross-country (XC) skiing in recent decades, as well as potential future developments. XC skiing has been an Olympic event since the very first Winter Games in Chamonix, France, in 1924. Over the past decades, considerable developments in skiing techniques and improvements in equipment and track preparation have increased skiing speed. In contrast to the numerous investigations on the physiological determinants of successful performance, key biomechanical factors have been less explored. Today’s XC skier must master a wide range of speeds, terrains, and race distances and formats (e.g., dis…
Changes in biomechanics of skiing at maximal velocity caused by simulated 20 km skiing race using V2 skating technique
2018
This study investigated how the fatigue caused by a 20-km simulated skating cross-country skiing race on snow affects the final spurt performance from a biomechanical perspective. Subjects performed a 100-m maximal skiing trial before and at the end of the simulated race. Cycle characteristics, ground reaction forces from skis and poles, and muscle activity from eight muscles were recorded during each trial. Results showed that subjects were in a fatigued state after the simulated race manifested by 11.6% lower skiing speed (P<.01). The lower skiing speed was related to an 8.0% decrease in cycle rate (P<.01), whereas cycle length was slightly decreased (tendency). In temporal patterns, rela…
Sleep Disturbances in COPD are Associated with Heterogeneity of Airway Obstruction
2018
Individuals with Chronic Obstructive Pulmonary Disease (COPD) experience sleep disturbances due to the impact of respiratory symptoms on sleep quality. We explored whether sleep disturbances in COPD are linked to heterogeneity of airway constriction.The impact of breathing problems on sleep quality was measured in consecutive COPD outpatients with the COPD and Asthma Sleep Impact Scale (CASIS) questionnaire. Impulse oscillometry technique (IOS) was employed to assess heterogeneity of airway constriction. Subjects with a previous or concomitant diagnosis of asthma or obstructive sleep apnea (OSA) were excluded.Fifty COPD subjects (M/F 40/10; age: 71 +/- 8 yrs, Body Mass Index (BMI): 26.2 +/-…
Local mechanical properties by Atomic Force Microscopy nanoindentations
2008
The analysis of mechanical properties on a nanometer scale is a useful tool for combining information concerning texture organization obtained by microscopy with the properties of individual components- Moreover, this technique promotes the understanding of the hierarchical arrangement in complex natural materials as well in the case of simpler morphologies arising from industrial processes. Atomic Force Microscopy, AFM, can bridge morphological information, obtained with outstanding resolution, to local mechanical properties. When performing an AFM nanoindentation, the rough force curve, i.e., the plot of the voltage output from the photodiode vs. the voltage applied to the piezo-scanner, …
Combined Use of Structure Analysis, Studies of Molecular Association in Solution, and Molecular Modelling to Understand the Different Propensities of…
2021
The arrangement of hydroxyl groups in the benzene ring has a significant effect on the propensity of dihydroxybenzoic acids (diOHBAs) to form different solid phases when crystallized from solution. All six diOHBAs were categorized into distinctive groups according to the solid phases obtained when crystallized from selected solvents. A combined study using crystal structure and molecule electrostatic potential surface analysis, as well as an exploration of molecular association in solution using spectroscopic methods and molecular dynamics simulations were used to determine the possible mechanism of how the location of the phenolic hydroxyl groups affect the diversity of solid phases formed…
Chasing Weak Forces: Hierarchically Assembled Helicates as a Probe for the Evaluation of the Energetics of Weak Interactions.
2017
London dispersion forces are the weakest interactions between molecules. Because of this, their influence on chemical processes is often low, but can definitely not be ignored, and even becomes important in cases of molecules with large contact surfaces. Hierarchically assembled dinuclear titanium(IV) helicates represent a rare example in which the direct observation of London dispersion forces is possible in solution even in the presence of strong cohesive solvent effects. Hereby, the dispersion forces do not unlimitedly support the formation of the dimeric complexes. Although they have some favorable enthalpic contribution to the dimerization of the monomeric complex units, large flexible…
Computational Rationality as a Theory of Interaction
2022
Funding Information: This work was funded by the Finnish Center for AI and Academy of Finland (“BAD” and “Human Automata”). We thank our reviewers, Xiuli Chen, Joerg Mueller, Christian Guckelsberger, Sebastiaan de Peuter, Samuel Kaski, Pierre-Alexandre Murena, Antti Keuru-lainen, Suyog Chandramouli, and Roderick Murray-Smith for their comments. Publisher Copyright: © 2022 ACM. How do people interact with computers? This fundamental question was asked by Card, Moran, and Newell in 1983 with a proposition to frame it as a question about human cognition - in other words, as a matter of how information is processed in the mind. Recently, the question has been reframed as one of adaptation: how …
Social Workers’ Reflections on Forced Migration and Cultural Diversity : Towards Anti-Oppressive Expertise in Child and Family Social Work
2021
Social work in Finland, like in many other countries, has faced various challenges after the large scale of forced migration in 2015. Although working with migrants is not a new area in social work, the exceptionally large amount of asylum seekers in the Finnish society caused a need for improved social work expertise. Our article deals with Finnish social work practitioners’ reflections on multicultural, multilingual and transnational issues with a client group, which is in a vulnerable situation after forced or other forms of migration. The practitioners participating in our study have either attended a specializing education of child, youth and family social work or taken part in peer gr…
Durabilità, in ambiente fortemente basico, delle fibre di PET provenienti dalla raccolta differenziata
2012
La sperimentazione esposta nella presente pubblicazione tratta dell’impiego di fibre di PET, ricavate dal semplice taglio di contenitori per bevande secondo un procedimento brevettato, nel rinforzo di calcestruzzi destinati anche a impieghi strutturali. Descrive le caratteristiche geometriche delle fibre e ne indaga la durabilità in condizioni severe che potrebbero presentarsi in un’applicazione pratica quale una pavimentazione esterna. A tal fine campioni costituiti da gruppi di fibre sono stati immersi per tredici giorni a 65°C in soluzioni a differente concentrazione di NaOH (0,103 M e 1,75 M). In particolare la soluzione a concentrazione 0,103 M di NaOH (pH=13) simula la basicità della …
Przepis art. 299 Kodeksu spółek handlowych jako funkcja prawa o niewypłacalności
2022
Przepis art. 299 Kodeksu spółek handlowych nawiązuje do treści art. 298 Kodeksu handlowego. Polski ustawodawca model spółki z ograniczoną odpowiedzialnością generalnie oparł na regulacji niemieckiej. Niemniej z uwagi na częste przypadki nadużywania formy spółki kapitałowej wprowadził szczególną odpowiedzialność członków zarządu. Regulacja art. 299 Kodeksu spółek handlowych przez lata była przedmiotem ożywionej debaty nauko-wej i wielu orzeczeń sądowych. W niniejszym opracowaniu stawiana jest teza, że wskazana regulacja jest funkcją prawa upadłościowego. Konsekwencją tej tezy jest wskazanie na zakres odpowiedzialności członka zarządu spółki z ograniczoną odpowiedzialnością, który podej-mie o…