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Monitoring the Performance of Alpine Skiers with Inertial Motion Units: Practical and Methodological considerations

Journal of Science in Sport and Exercise 2021年第3期3卷 249-256页

作者： Matej Supej H-c Holmberg Faculty of Sport University of LjubljanaGortanova ulica 221000 LjubljanaSlovenia Swedish winter Sports Research centre Mid Sweden UniversityOstersundSweden Department of Physiology and Pharmacology Biomedicum C5Karolinska InstitutetStockholmSweden china Institute of Sport and Health Science Beijing Sport UniversityBeijingChina

Although reliable feedback is crucial to improving the performance of competitive alpine skiers,the coach’s eye may not be sensitive enough to detect small,but highly significant“mistakes”.Monitoring of the performance of alpine ski racers by inertial motion units(IMU)has proven to be of value in this context and here we summarize practical and methodological aspects of this ***,the IMUs employed should combine high sampling frequencies with minimal signal *** sensors should be positioned to sense the movement of the bones in a given body segment while being pro-tected as much as possible against impact with the ski *** data obtained,often synchronized with input from Global Satellite Navigation Systems(GNSS),are usually refined utilizing advanced biomechanical models and other computerized *** practice,the combination of inertial sensors and GNSS allows accurate monitoring of skiing kinematics(technique)and the movement of the skier’s center-of-mass,also allowing analysis of both whole-body vibrations(WBV)and loss of mechanical *** of the findings to coaches and athletes can be facilitated by synchronizing them with video *** advances in IMU technology,including miniaturization,wireless communication,direct stor-age of data in the cloud,and processing with artificial intelligence may allow these sensors,in-combination with GNSS,to become real-time virtual alpine ski coaches,perhaps the next step in the development of this sport.

关键词： Biomechanics GPS GLONASS Kinematics IMU Technique

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A SIMPLE METHOD FOR THE INcORPORATION OF LOW MOLEcULAR WEIGHT DYES IN ULTRATHIN FILMS

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chinese Journal of Polymer Science 2003年第6期21卷 631-637页

作者： c. Geraldine Bazuin carmen M. Tibirna centre de Recherche en Sciences et Ingenierie des Macromolecules (cERSIM) Departement de Chimie Universite Laval Qudbec (QC). Canada GIK 7P4 Departement de chimie Universite de Montreal C.P. 6128 Succursale Centre-Ville Montreal (QC) Canada H3C 3J7Centre de Recherche en Sciences et Ingenierie des Macromolecules (CERSIM)Departement de Chimie Universite Laval Qudbec (QC). Canada GIK 7P4

A simple method for the fabrication of ultrathin films containing low molecular weight dye material is introduced(post-adsorption technique). The chromophore used is 4-nitro-4'-decyloxy azobenzene quaternary ammonium salt (azo-10Q).In classical layer-by-layer (LBL) procedures, where the substrate is dipped alternately into the chromophore solution and thecomplementary polyelectrolyte, the chromophore tends to desorb from the film during subsequent immersion in thepolyanion solution, and there is little or no indication of multilayer growth. The extent of desorption depends somewhat onthe selection of polyelectrolyte, the ionic strength and the pH of solution. An alternative approach is to first prepareconventional LBL films from a pair of oppositely charged polyelectrolytes, and then to soak this film into the chromophoresolution, where adsorption by penetration into the LBL film may take place. In preliminary results, a linear dependence ofUV absorbance on layer number of LBL film thus prepared was found, demonstrating the apparent effectiveness of the post-adsorption technique for the preparation of azo-10Q-containing ultrathin films.

关键词： Ultrathin films Layer-by-layer Azo derivatives Polyelectrolytes Supramolecular complexes

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characteristic Study of the Boundary Layer Parameters over the Arabian Sea and the Bay of Bengal Using the QuikScAT Dataset

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Advances in Atmospheric Sciences 2007年第4期24卷 631-643页

作者： V.HAMZA c.A.BABU T.P.SABIN Department of Atmospheric Sciences Cochin University of Science and TechnologyCochin-682 016India

The marine atmospheric boundary layer （MABL） plays a vital role in the transport of momentum and heat from the surface of the ocean into the atmosphere. A detailed study on the MABL characteristics was carried out using high-resolution surface-wind data as measured by the QuikScAT （Quick scatterometer） satellite. Spatial variations in the surface wind, frictional velocity, roughness parameter and drag coefficient for the different seasons were studied. The surface wind was strong during the southwest monsoon season due to the modulation induced by the Low Level Jetstream. The drag coefficient was larger during this season, due to the strong winds and was lower during the winter months. The spatial variations in the frictional velocity over the seas was small during the post-monsoon season （-0.2 m s^-1）. The maximum spatial variation in the frictional velocity was found over the south Arabian Sea （0.3 to 0.5 m s^-1） during the southwest monsoon period, followed by the pre-monsoon over the Bay of Bengal （0.1 to 0.25 m s^-1）. The mean wind-stress curl during the winter was positive over the equatorial region, with a maximum value of 1.5×10^-7 N m^-3, but on either side of the equatorial belt, a negative wind-stress curl dominated. The area average of the frictional velocity and drag coefficient over the Arabian Sea and Bay of Bengal were also studied. The values of frictional velocity shows a variability that is similar to the intraseasonal oscillation （ISO） and this was confirmed via wavelet analysis. In the case of the drag coefficient, the prominent oscillations were ISO and quasi-biweekly mode （QBM）. The interrelationship between the drag coefficient and the frictional velocity with wind speed in both the Arabian Sea and the Bay of Bengal was also studied.

关键词： boundary layer characteristics drag coefficient frictional velocity roughness length QuikScAT wind

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Study of Transition from Laminar to Turbulent Boundary Layer on a Tilted Flat Plate Using Heat Transfer Measurements

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Journal of Thermal Science 2007年第2期16卷 186-191页

作者： E.Sanz c.Nicot R.Point F.Plaza Laboratoire de Mécanique des Fluides et Acoustique LMFA(ECL-UCB-INSA Lyon-CNRS)36Avenue Guy de Collongue69134 Ecully.France.

The boundary layer transition over a flat tilted plate has been studied by means of heat transfer measurements. A heat flux sensor has been developed, in order to measure the efficiency of convective heat transfer for various types of surfaces or flows. Its operation at constant temperature allows direct and fast measurements of heat flux. The present paper reports the development of the sensor and presents its application to the study of transition in a boundary layer depending on the angle of incidence of the external flow. An exponential relationship between critical Reynolds number and pressure gradient parameter has been found.

关键词： convective heat flux boundary layer transition pressure gradient.

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Impact of introducing a herb pasture area into a New Zealand sheep and beef hill country farm system: a modeling analysis

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Frontiers of Agricultural Science and Engineering 2018年第1期5卷 87-97页

作者： cécile DURANTON cory MATTHEW Institute of Agriculture and Environment Massey University

New Zealand is well known for export of meat and dairy products from low cost pastoral systems. These farm systems are continually evolving for increased efficiency, in part through the use of metabolic energy modeling tools by farmers and farm consultants to explore alternative farm system configurations and identify new efficiencies. One recent innovation is the introduction of a herb pasture area, such as plantain. We used metabolic energy modeling to quantify seasonal feed flows in two successive years in a New Zealand hill country farm system, and to analyze the impact of the introduction of an area of plantain. Models employed were a self-built Microsoft Excel spreadsheet and a commercial New Zealand farm systems modeling package, *** production, animal performance and financial results for a base farm scenario created from the average of survey data for hill farms in the southern North Island, and the same farm with 10% and 20% of the area in plantain for the years 2010–2011 and 2011–2012 were modeled. The self-built model performed similarly to the commercial model. The system configuration of the base farm stockpiles surplus autumn feed for release to animals in winter and also incorporates flexibility that confers resilience to interannual weather variation through varying dates animals are purchased or sold. The introduction of an area of plantain was predicted to increase herbage production, animal performance and financial *** predicted benefit was higher for the year 2010–2011 where a drought occurred in summer than for the following year with higher summer rainfall. This demonstrates the profitability of introducing a plantain area to New Zealand hill farm systems, and suggests plantain will assist to mitigate adverse effects of warmer and drier summer conditions associated with current climate change trends.

关键词： farm system configuration herb pasture metabolic energy budgeting plantain sheep and beef farming

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Single Mutations in the Transmembrane Domains of Maize Plasma Membrane Aquaporins Affect the Activity of Monomers within a Heterotetramer

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Molecular Plant 2016年第7期9卷 986-1003页

作者： Marie c. Berny Dimitri Gilis Marianne Rooman Francois chaumont Institut des Sciences de la Vie University catholique de Louvain 1348 Louvain-la-Neuve Belgium Bioinformatique genomique et structurale Universite Libre de Bruxelles 1050 Brussels Belgium

Aquaporins are channels facilitating the diffusion of water and/or small uncharged solutes ecross biological membranes. They assemble as homotetramers but some of them also form heterotetramers, especially in plants. In Zea mays, aquaporins belonging to the plasma membrane intrinsic protein （PIP） subfamily are clustered into two groups, PIP1 and PIP2, which exhibit different water-channel activities when expressed in Xenopus oocytes. When PIP1 and PIP2 isoforms are co-expressed, they physically interact to modulate their subcellular localization and channel activity. Here, we demonstrated by affinity chromatography purification that, when co-expressed in Xenopus oocytes, the maize PIP1;2 and PIP2;5 isoforms assemble as homo- and heterodimers within heterotetramers. We built the 3D structure of such heterotetramers by comparative modeling on the basis of the spinach SoPIP2;1 X-ray structure and identified amino acid residues in the transmembrane domains which putatively interact at the interfaces between monomers. Their roles in the water-channel activity, subcellular localization, protein abundance, and physical interac- tion were investigated by mutagenesis. We highlighted single-residue substitutions that either inactivated PIP2;5 or activated PIP1;2 without affecting their interaction. Interestingly, the Phe220Ala mutation in the transmembrane domain 5 of PIP1 ;2 activated its water-channel activity and, at the same time, inactivated PIP2;5 within a heterotetramer. Altogether, these data contribute to a better understanding of the interaction mechanisms between PIP isoforms and the role of heterotetramerization on their water-channel activity.

关键词： aquaporin heterotetramer mutation oligomerization water-channel activity

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The cold Tongue in the South china Sea during Boreal winter and Its Interaction with the Atmosphere

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Advances in Atmospheric Sciences 2010年第2期27卷 265-273页

作者： Hamza VARIKODEN A. A. SAMAH c. A. BABU National Antarctic Research centre University of Malaya IPS BuildingKuala Lumpur-50603 Malaysia climatology and Hydrometeorology Division Indian Institute of Tropical Meteorology

A distinct cold tongue has recently been noticed in the South china Sea during the winter monsoon, with the cold tongue temperature minimum occurring in the January or February. This cold tongue shows significant links with the Maritime continent＇s rainfall during the winter period. The cold tongue and its interaction with the Maritime continent＇s weather were studied using Reynolds SST data, wind fields from the NcEP-NcAR reanalysis dataset and the quikScAT dataset. In addition, rainfall from the GOES Precipitation Index （GPI） for the periods 2000 to 2008 was also used. The propagation of the cold tongue towards the south is explained using wind dynamics and the western boundary current. During the period of strong cold tongue, the surface wind is strong and the western boundary current advects the cold tongue to the south. During the period of strong winds the zonal gradient of SST is high [0.5 °c （25 km）-1 ]. The cold tongue plays an important role in regulating the climate over the Maritime continent. It creates a zonal/meridional SST gradient and this gradient ultimately leads in the formation of convection. Hence, two maximum precipitation zones are found in the Maritime continent, with a zone of relatively lower precipitation between, which coincides with the cold tongue＇s regions. It was found that the precipitation zones have strong links with the intensity of the cold tongue. During stronger cold tongue periods the precipitation on either side of the cold tongue is considerably greater than during weaker cold tongue periods. The features of convection on the eastern and western sides of the cold tongue behave differently. On the eastern side convection is preceded by one day with SST gradient, while on the western side it is four days.

关键词： cold tongue SST gradient wind precipitation

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Indo-Japanese Lidar Observations of the Tropical Middle Atmosphere During 1998 and 1999

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Advances in Atmospheric Sciences 2006年第5期23卷 711-725页

作者： Y.BHAVANI KUMAR c.NAGESWARA RAJU M. KRISHNAIAH National MST Radar Facility P. B. No: 123 Tirupati-517 502 A. P. India Department of Physics S.V. University Tirupati-517 502 A. P. India

A state-of-the art Rayleigh and Mie backscattering lidar was set up at Gadanki （13.5°N, 79.2°E） in the Tropics in India. Using this system, regular observations of upper tropospheric clouds, aerosols at stratospheric heights and atmospheric temperatures in the range from 30 to 80 km were made. In this paper, the data collected during the period of 1998-99 were selected for systematic investigation and presentation. The Mie scattering lidar system is capable of measuring the degree of depolarization in the laser backscattering. Several tropical cirrus cloud structures have been identified with low to moderate ice content. Occasionally, thin sub-visible cirrus clouds in the vicinity of the tropical tropopause have also been detected. The aerosol measurements in the upper troposphere and lower stratosphere show low aerosol content with a vertical distribution up to 35 km altitude. Rayleigh-scattering lidar observations reveal that at the tropical site, temperature inversion occurs at mesospheric heights. Atmospheric waves have induced perturbations in the temperatures for several times at the upper stratospheric heights. A significant warming in the lower mesosphere associated with a consistent cooling in the upper stratospheric heights is observed particularly in the winter season during the events of sudden stratospheric warming （ssw）.

关键词： backscatter lidax tropical atmosphere cirrus stratospheric aerosol gravity waves middleatmospheric temperatures upper stratospheric cooling

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characterization and Photoluminescence Properties of Alumina Nanowires Elaborated by Arc-Plasma

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Journal of Materials Science & Technology 2006年第1期22卷 127-129页

作者： c.Arnoult X.Devaux H.Rinnert M.Vergnat Laboratoire de Physique des Materiaux UMR CNRS 7556Ecole des MinesCS14234F54042 Nancy cedexPrance

Ultrafine powders containing alumina nanowires are synthesized by Dc arc plasma from pure aluminium metal. Nanowires grow only when reactive gases are composed of nitrogen and less than ten percent of oxygen. Nanowires have the diameters ranging from 20 to 80 nm and lengths ranging from hundreds nanometers to tens of micrometers. A first assumption of the mechanism process is proposed, in which nanowires grow starting directly from the aluminium. Photoluminescence measurements show that the powders have three emission peaks around 435, 530 and 750 nm resulting from different kinds of defects such as oxygen vacancies, aluminium interstitial ions and surface defects.

关键词： Nanowires Alumina Arc plasma Photoluminescence

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Effect of nitrogen fertilizer on biomass production and nodulation behavior of Pongamia pinnata Pierre seedlings under nursery conditions

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Journal of Forestry Research 2013年第3期24卷 531-538页

作者： S.P. chaukiyal Rayees Afzal Mir T.c. Pokhriyal Plant Physiology Botany Division. Forest Research InstituteDehradun Uttarakhand India

At the seedling stage, a small amount of N is required to boost growth of leguminous plants. A pot experiment was conducted to observe the effect of N fertilizer on various growth parameters and nodulation behavior of Pongamia pinnata under nursery conditions. After the estab- lishment of seedlings, four nitrogen treatments, 0, 40, 80 and 100 kg-ha^-1 N were applied in two equal splits. Monthly observations were taken for the morphological parameters viz. plant height, collar diameter, leaf number, root length, root shoot ratio, nodule number and weight per plant. Maximum plant height was recorded after application of N at 40 ***^-1. Seasonally, the difference in collar diameter in rainy season was signifi- cantly higher than in winter or summer. However, more leaves were produced per plant at N-40 and N-100 treatments in winter and rainy seasons. Higher root length was recorded in rainy season than in winter or summer. Root biomass was higher than for stems or leaves. Seasonal effects of N-80 and N-40 treatments on leaf dry weight were significantly higher than for N-100 or N-0. Stem dry weight was higher at N-40 than at other treatments in winter and summer seasons. Root：shoot ratio was higher throughout winter to early summer. Nodule biomass was 2-3 times higher in rainy season compared to winter or summer. Maximum nodule number and biomass per plant were highest at N-40, followed by N-0, N-80 and N-100 treatments. New nodule formation started from June to the end of September. Maximum biomass per plant was recorded at N-40, followed by N-80, N-100 and N-0. Nitrogen treatment effect and seasonal behaviour interaction were not significant. Significantly higher numbers of nodules per plant were recorded in rainy season followed by summer and winter for all treatments. Higher nitrogen doses suppressed growth while lower doses promoted growth in Pongamia pinnata. Therefore, the lower nitrogen dose i.e., N-40 ***^-1 applied in two equal splits was suitable at the

关键词： Pongamia pinnata biomass nitrogen treatments seasonalbehaviour

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