WorldWideScience

Sample records for ice skating rinks

  1. Nitrogen dioxide exposures inside ice skating rinks.

    Science.gov (United States)

    Brauer, M; Spengler, J D

    1994-01-01

    OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

  2. Skating on thin ice: a study of the injuries sustained at a temporary ice skating rink.

    Science.gov (United States)

    Barr, Lynne V; Imam, Samirul; Crawford, John R; Owen, P Julian

    2010-06-01

    In recent years, ice skating and temporary ice skating rinks have become increasingly popular. Regular elite competitors are known to be at risk of both acute and chronic injuries. It may be postulated that skaters at the temporary rinks are at high risk of acute injuries from falls due to both their lack of expertise and the inherent dangers of ice skating. Injuries sustained at skating rinks present a significant burden to local healthcare resources, in particular orthopaedic departments. For the first time, Cambridge hosted such a facility from November 24, 2007 through January 6, 2008. We sought to identify the most common injuries encountered and to quantify the orthopaedic burden. All Emergency Department or Fracture Clinic attendances for an eight-week period from the opening of the rink were investigated. Details of age, sex, injury and management were recorded for the 84 patients who sustained ice rink related injuries. A total of 85 injuries were recorded in 84 patients. Of these injuries 58% were fractures, of which 98% involved the upper limbs. Seven patients (8% of all injuries) required admission for operative fixation. On average, two injuries per day were seen in the Emergency Department or Fracture Clinic, with an average of one orthopaedic admission per week. It is evident that the ice rink in Cambridge has had an impact on local healthcare resources. The vast majority of injuries affected the upper limbs and were sustained following a fall on the out-stretched hand. We therefore encourage the education of skaters as to how to break their falls more safely and recommend the use of wrist protectors as a primary preventative measure.

  3. Indoor air quality in ice skating rinks in Hong Kong

    International Nuclear Information System (INIS)

    Guo, H.; Lee, S.C.; Chan, L.Y.

    2004-01-01

    Indoor air quality in ice skating rinks has become a public concern due to the use of propane- or gasoline-powered ice resurfacers and edgers. In this study, the indoor air quality in three ice rinks with different volumes and resurfacer power sources (propane and gasoline) was monitored during usual operating hours. The measurements included continuous recording of carbon monoxide (CO), carbon dioxide (CO 2 ), total volatile organic compounds (TVOC), particulate matter with a diameter less than 2.5 μm (PM 2.5 ), particulate matter with diameter less than 10 μm (PM 10 ), nitric oxide (NO), nitrogen dioxide (NO 2 ), nitrogen oxide (NO x ), and sulfur dioxide (SO 2 ). The average CO, CO 2 , and TVOC concentrations ranged from 3190 to 6749 μg/m 3 , 851 to 1329 ppm, and 550 to 765 μg/m 3 , respectively. The average NO and NO 2 concentrations ranged from 69 to 1006 μg/m 3 and 58 to 242 μg/m 3 , respectively. The highest CO and TVOC levels were observed in the ice rink which a gasoline-fueled resurfacer was used. The highest NO and NO 2 levels were recorded in the ice rink with propane-fueled ice resurfacers. The air quality parameters of PM 2.5 , PM 10 , and SO 2 were fully acceptable in these ice rinks according to HKIAQO standards. Overall, ice resurfacers with combustion engines cause indoor air pollution in ice rinks in Hong Kong. This conclusion is similar to those of previous studies in Europe and North America

  4. The impact of orthopaedic injuries sustained at an urban public ice skating rink: is it really free?

    Science.gov (United States)

    Schwarzkopf, Ran; Nacke, Elliot A; Tejwani, Nirmal C

    2014-01-01

    Previous reports in the literature from Europe and Asia cite an increased burden on the local emergency departments and orthopaedic services during the operational period of the ice skating rinks. This retrospective observational study was undertaken in order to report the incidence, characteristic, and severity of injuries during a full season at a large urban ice skating rink, as well as to quantify the added burden the ice skating rink places on the local emergency department and the orthopaedic service. All patients seen at our emergency room who sustained an injury at the neighboring "free" ice rink were identified over the 4-month period when it was open. The data collected included type of injury, demographics, and need for surgical treatment. Over this period, 118 patients were seen in our ED (of the 135 referrals from the ice rink logbook); Of these, 43 (38%) required an orthopaedic consult and were evenly divided into upper (22) and lower extremity injuries (21). Sixty-seven percent of the patients were adults, and the most common fractures were ankle and distal radius fractures. There were two open fractures of the distal radius seen in the older patients (both in patients > 50). Overall 32% of patients needed operative treatment. Of the non-orthopaedic injuries, the most common was head injury (25%). An ice-rink may be "free" but adds significant burden to the healthcare system, and these costs should be factored in by both the sponsoring body and the healthcare system for treatment of these additional patients.

  5. The Jaap Eden ice skating rink was ahead of its time; Jubilerende Jaap Eden kunstijsbaan was tijd ver vooruit

    Energy Technology Data Exchange (ETDEWEB)

    Berends, E. [GEA Grenco, Den Bosch (Netherlands); Knipscheer, H.J.M. [Ingenieursbureau Knipscheer, Soest (Netherlands)

    2012-01-15

    In 1959, interest in a 400 meter track arose in the Netherlands as a result of the success of the Dutch skaters. The design and realization of the ice rink in Amsterdam was conducted by Grasso. On 22 December 2011, it was fifty years ago that the Jaap Eden ice skating rink was officially opened. A short overview is given of the construction, the cooling installation, safety and other special aspects and the renovation that took place in 1994. [Dutch] In 1959 ontstond er in Nederland als gevolg van de successen van de Nederlandse schaatsers interesse in een 400-meterbaan. Het ontwerp en de realisatie van een ijsbaan in Amsterdam werden uitgevoerd door Grasso. Op 22 december 2011 was het vijftig jaar geleden dat de Jaap Edenbaan officieel geopend werd. Een kort overzicht van de bouw, koelinstallatie, veiligheid, andere bijzondere aspecten en de renovatie in 1994.

  6. A Case Study Of Applying Infrared Thermography To Identify A Coolant Leak In A Municipal Ice Skating Rink

    Science.gov (United States)

    Wallace, Jay R.

    1989-03-01

    This paper deals with the application of infrared imaging radiometry as a diagnostic inspection tool for locating a concealed leak in the refrigeration system supplying glycol coolant to the arena floor of an ice skating rink in a municipal coliseum facility. Scanning approximately 10 miles of black iron tubing embedded in the arena floor resulted in locating a leak within the supply/return side of the system. A secondary disclosure was a restriction to normal coolant flow in some delivery loops caused by sludge build-up. Specific inspection procedures were established to enhance temperature differentials suitable for good thermal imaging. One procedure utilized the temperature and pressure of the city water supply; a second the availability of 130F hot water from the facility's boiler system; and a third the building's own internal ambient temperature. Destructive testing and other data collection equipment confirmed the thermographic findings revealing a section of corrosion damaged pipe. Repair and flushing of the system was quickly completed with a minimum of construction costs and inconvenience. No financial losses were incurred due to the interruption of scheduled revenue events. Probable cause for the shutdown condition was attributed to a flawed installation decision made 15 years earlier during the initial construction stage.

  7. Study on application of single-crystal ice `Kurobe ice column` to high-speed skating rinks. Demonstration test result at Olympic memorial arena `M wave` in Nagano city; Tankesshohyo `Kurobe no hyojun` no kosoku skate link eno tekiyosei kenkyu. Naganoshi olympic kinen arina `Emu Wave` deno jissho shiken kekka

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, M. [Kansai Electric Power Co. Inc., Osaka (Japan)

    1999-06-10

    For high-speed low-friction skating rinks, research was made on sticking artificial ice columns (ice bamboo shoot). The ice columns were fabricated with the ice column production equipment equipped with 4-line water droplet dropping devices which were installed at intervals of 0.3m on both sides of a pathway of 200m long, 2.6m wide and 1.8m high in the lateral adit of Kurobegawa No.4 hydroelectric power station. The grown ice columns were processed for high-speed skating rinks through cutting, confirmation of single crystal and crystal orientation, slicing for every 7mm thickness and packaging. The ice columns were spread all over the rink while sliding them to prevent mixing of bubbles after spraying distilled water of nearly 25 degreesC onto base ices. In addition, hot water of nearly 40 degreesC was sprayed to produce the final ice rink of 30mm thick by nearly 5mm a day. The dynamic friction coefficient of the ice column rink reduced to 0.0038 by nearly 16% as compared with 0.0045 of conventional rinks. (NEDO)

  8. The first ice skating rink in the world (Glaciarium) and it's remarkable inventor John Gamgee; De allereerste kunstijsbaan ter wereld en de opmerkelijke uitvinder John Gamgee

    Energy Technology Data Exchange (ETDEWEB)

    Berends, E. [Grenco, Den Bosch (Netherlands)

    2005-02-15

    Some historical aspects are given of the development of the first ice skating rink (Glaciarium) that was opened in 1876 in Chelsea, London, UK. Also attention is paid to the inventor of the skating rink, professor dr. John Gamgee and some of the other inventions of this remarkable person. [Dutch] De historie van de eerste kunstijsbaan (Glaciarium) die in 1876 in Chelsea in Londen werd geopend, wordt uit de doeken gedaan. Daarnaast wordt aandacht geschonken aan de uitvinder, professor dr. John Gamgee, en worden enkele andere uitvindingen van deze opmerkelijke man belicht.

  9. Roof radiation in indoor and covered outdoor skating rinks; Deckenstrahlung in Eishallen und ueberdeckten Ausseneisfeldern

    Energy Technology Data Exchange (ETDEWEB)

    Gachnang, F. [Eta Energietechnik GmbH, Winterthur (Switzerland); Mayer, H. [Gabathuler AG, Diessenhofen (Switzerland); Schweizer, A. [Baumgartner und Partner AG, Duebendorf (Switzerland); Krieg, J. [Zuercher Hochschule Winterthur, Winterthur (Switzerland)

    2005-07-01

    This report for the Swiss Federal Office of Energy (SFOE) presents the results of three measurement projects that examined the effect of low-emission materials mounted under the roofing in three different ice rinks on the energy consumption for the refrigeration and air-conditioning installations. In the first object, an indoor ice-hockey rink in Duebendorf, Switzerland, the effect of an aluminium cladding installed and the measurements made concerning the reduction of energy consumption are discussed. Their relevance to further covered ice rinks is examined. The second part takes a look at the effect of soiling and oxidation examined at a further skating rink in Kreuzlingen, Switzerland. The third part of the report examines three different roofing constructions newly installed over an outdoor rink. The findings of the three projects are discussed and recommendations are made.

  10. How Much Water Is in the Skating Rink?

    Science.gov (United States)

    Ameis, Jerry A.

    2004-01-01

    This article describes activities for developing an understanding of a formula for calculating the volume of a rectangular prism. The core activity concerns determining the volume of water in a backyard skating rink. (Contains 4 figures.)

  11. Study on application of single-crystal ice 'Kurobe ice column' to high-speed skating rinks. Demonstration test result at Olympic memorial arena 'M wave' in Nagano city. Tankesshohyo 'Kurobe no hyojun' no kosoku skate link eno tekiyosei kenkyu. Naganoshi olympic kinen arina 'Emu Wave' deno jissho shiken kekka

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, M. (Kansai Electric Power Co. Inc., Osaka (Japan))

    1999-06-10

    For high-speed low-friction skating rinks, research was made on sticking artificial ice columns (ice bamboo shoot). The ice columns were fabricated with the ice column production equipment equipped with 4-line water droplet dropping devices which were installed at intervals of 0.3m on both sides of a pathway of 200m long, 2.6m wide and 1.8m high in the lateral adit of Kurobegawa No.4 hydroelectric power station. The grown ice columns were processed for high-speed skating rinks through cutting, confirmation of single crystal and crystal orientation, slicing for every 7mm thickness and packaging. The ice columns were spread all over the rink while sliding them to prevent mixing of bubbles after spraying distilled water of nearly 25 degreesC onto base ices. In addition, hot water of nearly 40 degreesC was sprayed to produce the final ice rink of 30mm thick by nearly 5mm a day. The dynamic friction coefficient of the ice column rink reduced to 0.0038 by nearly 16% as compared with 0.0045 of conventional rinks. (NEDO)

  12. A modern approach to designing ice rinks and arenas

    Energy Technology Data Exchange (ETDEWEB)

    Kosonen, R.; Laitinen, A. [VTT Building Technology (Finland)

    1998-06-01

    Energy consumption and operating costs are important issues for ice-skating rinks, where they have to be considered alongside indoor climate and ice quality. The energy consumption of an ice area is determined by its construction characteristics, plant system and operational aspects. Another key factor is the ice; most energy flows are connected in some way to the refrigeration process. The potential for energy savings, design features that help to reduce operating costs, the energy audit programme coordinated by the Finnish Ice Hockey Association and the example of the renovation of an ice rink at Laitila in Finland are described. The components of energy efficient ice areas (lighting, ice resurfacing, ventilation, refrigeration, automation, construction and envelope) are summarised in a diagram.

  13. Ice-skating injuries.

    Science.gov (United States)

    Williamson, D M; Lowdon, I M

    1986-05-01

    The range of injuries sustained at an ice-rink and presented to an Accident Service department is described. A total of 203 patients with 222 injuries presented themselves during a 2-month period. There were 103 noteworthy injuries, including 61 fractures, 2 dislocations and 2 severed tendons, but the commonest injuries were wounds, sprains and bruises. Beginners appear to be more prone to injury than experienced skaters. In addition to using well-fitting skate-boots to protect the ankle, some injuries could be avoided by wearing elbow and knee pads, and a thick pair of gloves. The number of injuries compared with the total number of skaters was small but produced a noteworthy increase in the workload of the Accident Service.

  14. Efficient stratified ventilation - air conditioning of skating rinks; Effiziente Schichtlueftung - Klimatisierung von Eissporthallen

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, E. [Fa. Caverion, Aachen (Germany)

    2007-07-01

    Air conditioning of ice rinks is not just a matter of user comfort. Excessive humidity will cause frosting and poor ice quality while mist formation may interfere with hockey games. Constant condensation in the roof area causes severe damage of the building and is assumed to be a maine cause of the breakdown of the Bad Reichenhall skating hall in January 2006. In the Wolfsburg ice arena, an innovative ventilation concept was implemented which meets complex user demands and is characterized by its high energy efficiency. (orig.)

  15. Ice skating injuries: can they be reduced or prevented?

    Science.gov (United States)

    Oakland, C D

    1990-01-01

    The opening of an ice rink resulted in 469 attendances at the local Accident and Emergency department over the first year. One hundred and eight had a significant injury. Thirty-seven patients were admitted. Thirty-three required an operation under general anaesthesia. Thirty had consumed alcohol at the rink's bar. Nine of these had a fracture. The number of skates attending the Accident and Emergency department per 1000 visits to the rink declined over the study period. Injuries could be reduced if protective clothing was worn. Alcohol should not be sold at the rink. First aid although effective could be improved. PMID:2390159

  16. Cost of a roller skating rink to the local accident and emergency department.

    Science.gov (United States)

    Nayeem, N; Shires, S E; Porter, J E

    1990-01-01

    A 14 month retrospective study was undertaken to determine the cost implications of the opening of a roller skating rink to the local hospital accident and emergency department (A and E). A total of 398 patients attended following injury at the roller skating rink, of whom 384 were included in the study. The estimated cost of their injuries was determined by the hospital accounts department. The average cost per patient attending the A and E department following roller skating injury was about 100 pounds. The total cost to the A and E department of all injuries sustained at the rink over this period was 38,412 pounds. The cost implications of opening a roller skating rink for the A and E department are considerable. If proposals for self-budgeting are applied, A and E departments will have to seek additional funding if such leisure facilities are opened in their vicinity. PMID:2097020

  17. The impact of a temporary ice-rink on an emergency department service.

    LENUS (Irish Health Repository)

    Clarke, Heather J

    2012-02-03

    BACKGROUND: A temporary ice-rink opened close to Cork city for 6 weeks from 30 November 2003. During this time, a number of patients presented to the local emergency departments with ice-skating-related injuries. We documented these injuries. METHODS: All patients presenting to emergency departments in Cork city with ice-skating-related complaints were included. Information on age and sex, mechanism of injury, diagnosis, follow-up\\/disposition and ambulance service utilization was recorded. RESULTS: One hundred and twenty-five ice-rink-related attendances were reported at Cork emergency departments, representing 1.25% of total attendances. One hundred and twenty-three patients presented with skating-related injuries and two with medical complaints occurring at the ice-rink: 70.8% were female patients and 29.2% were male patients. In the 4-14-year age group, however, 48.5% were girls and 51.5% were boys. Most injuries were directly due to falls; 5.6% were due to skate blades. The commonest site of injury was the upper limb. Fractures and dislocations accounted for 53.9% of injuries, with 20.5% of these requiring orthopaedic admission. Lacerations and digital injuries accounted for 7.1%, with 11% of these required admission for surgery. One minor head injury was reported. 38.1% had soft tissue injuries. Fifteen patients were transported by ambulance. These attendances represented a minimum overall cost of 77,510 euro to the local health service. CONCLUSIONS: A temporary ice-rink had a significant impact on local emergency departments. Currently, there is no specific legislation in Ireland relating to public health and safety in ice-rinks. We recommend consultation with local public bodies before opening such facilities, and appropriate regulation.

  18. Energy efficient skating rink by heat recovery and CO2 refrigerant; Energiezuinige schaatsbaan door warmteterugwinning en CO2-koudedrager

    Energy Technology Data Exchange (ETDEWEB)

    Mooi, R. [IBK Compac, Houten (Netherlands)

    2009-03-15

    In October 2008 a new indoor skating rink was opened in Enschede, Netherlands. The refrigeration plant for this skating rink was designed, delivered and installed by IBK Compac. CO2 was chosen as the secondary refrigerant; CO2 is easily detectable, sustainable and - above all - very energy efficient, since less pumping energy is required and pipes with a smaller diameter can be used. The waste heat of the refrigeration plant is used for the Zamboni (ice resurfacer), for the central heating system and for the unique floor heating system, which is located under the skating rink. [Dutch] In oktober 2008 werd in Enschede de IJsbaan Twente geopend. Het werd een geheel overdekte schaatsbaan, waarvoor IBK Compac de koude-installatie heeft ontworpen, geleverd en geinstalleerd. Gekozen werd voor CO2 als secundaire koudedrager. CO2 is goed detecteerbaar, duurzaam en vooral zeer energie-efficient doordat er minder pompenergie nodig is en er leidingen met een kleinere diameter kunnen worden gebruikt. De restwarmte van de koelinstallatie wordt o.a. benut voor de dweilmachine (Zamboni), voor het cv-blok en voor het unieke vloerverwarmingssysteem dat onder de ijsbaan ligt.

  19. Skating on slippery ice

    Directory of Open Access Journals (Sweden)

    J. M. J. van Leeuwen

    2017-12-01

    Full Text Available The friction of a stationary moving skate on smooth ice is investigated, in particular in relation to the formation of a thin layer of water between skate and ice. It is found that the combination of ploughing and sliding gives a friction force that is rather insensitive for parameters such as velocity and temperature. The weak dependence originates from the pressure adjustment inside the water layer. For instance, high velocities, which would give rise to high friction, also lead to large pressures, which, in turn, decrease the contact zone and so lower the friction. The theory is a combination and completion of two existing but conflicting theories on the formation of the water layer.

  20. The effect of a complex training program on skating abilities in ice hockey players.

    Science.gov (United States)

    Lee, Changyoung; Lee, Sookyung; Yoo, Jaehyun

    2014-04-01

    [Purpose] Little data exist on systemic training programs to improve skating abilities in ice hockey players. The purpose of this study was to evaluate the effectiveness of a complex training program on skating abilities in ice hockey players. [Methods] Ten male ice hockey players (training group) that engaged in 12 weeks of complex training and skating training and ten male players (control group) that only participated in 12 weeks of skating training completed on-ice skating tests including a 5 time 18 meters shuttle, t-test, Rink dash 5 times, and line drill before, during, and the training. [Results] Significant group-by-time interactions were found in all skating ability tests. [Conclusion] The complex training program intervention for 12 weeks improved their skating abilities of the ice hockey players.

  1. Numerical calculation of air velocity and temperature in ice rinks

    Energy Technology Data Exchange (ETDEWEB)

    Bellache, O.; Galanis, N. [Sherbrooke Univ., PQ (Canada); Ouzzane, M.; Sunye, R. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Diversification Laboratory

    2002-07-01

    A computational fluid dynamic (CFD) model was developed to predict the energy consumption at an ice rink. Ice rinks in Canada consume approximately 3500 GWh of electricity annually and generate about 300,000 tons of gases contributing to the greenhouse effect. This newly developed model also considers ice quality and comfort conditions in the arena. The typical 2D configuration includes refrigeration loads as well as heat transfer coefficients between the air and the ice. The effects of heat losses through the ice rink envelope are also determined. A comparison of prediction results from 4 different formulations confirms that there are important differences in air velocities near the walls and in the temperature gradient near the ice. The turbulent mixed convection model gives the best estimate of the refrigeration load. It was determined that a good ventilation should circulate air throughout the building to avoid stagnant areas. Air velocities must be low near the stands where the temperature should be around 20 degrees C. Air temperature near the ice should be low to preserve ice quality and to reduce the refrigeration load. The complexity of this geometry has been taken into account in a numerical simulation of the hydrodynamic and thermal fields in the ice rink. 9 refs., 2 tabs., 5 figs.

  2. Ice Skating Instruction at the University of Illinois.

    Science.gov (United States)

    Christensen, Char; And Others

    1981-01-01

    The University of Illinois at Urbana-Champaign conducts a instructional ice skating program for its students and the community. Activities include: a figure skating club; a speed skating club; ice hockey program; and ice skating classes. (CJ)

  3. Germany's first CO{sub 2} skating rink. Axima Kaeltetechnik builds new skating rink at Ravensburg; Die erste CO{sub 2}-Kunsteisbahn Deutschlands. Axima Kaeltetechnik baut in Ravensburg

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2004-04-01

    Natural refrigerants are frequently used in skating rinks. Increasingly, CO2 is preferred to brine, as in the new Ravensburg skating rink. It is the first time this technology is applied in Germany, but more systems of this kind are sure to come. [German] Beim Bau von Kunsteisbahnen sind natuerliche Kaeltemittel kein Novum. Immer haeufiger erhaelt allerdings der Kaeltetraeger CO{sub 2} den Vorzug vor einer Sole, so auch beim Bau der neuen Kunsteisbahn in Ravensburg. Damit wurde erstmals in Deutschland in diesem Bereich der Schritt hin zu einer Systemtechnologie gemacht, die aller Voraussicht nach noch zahlreiche weitere Anwendungen nach sich ziehen wird. (orig.)

  4. Computer model of the refrigeration system of an ice rink

    Energy Technology Data Exchange (ETDEWEB)

    Teyssedou, G.; Zmeureanu, R. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Giguere, D. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Technology Centre

    2008-07-01

    This paper presented a refrigeration system model of an existing ice rink using a component approach. The chillers, the ice-concrete slab and the controller were the 3 main components used in the simulations which were performed using both open and closed loop systems. The simulated ice rink refrigeration system was based on measurements taken in an existing indoor ice rink located in Montreal, Quebec. Measurements of the refrigeration system included electricity demand; heat flux on the ice sheet; exterior air temperature; ice temperature; return brine temperature; brine temperature at the pump; brine temperature at both evaporator exits; and refrigerant temperature and pressure at the expansion and condenser valve exits. Simulation results and measurements were found to be in good agreement. A computer model of the refrigeration system was developed using the TRNSYS 16 program. The refrigeration system was composed of 2 chillers using refrigerant R-22. The impact of heat recovery from the condensers on the energy demand for sanitary water heating was also estimated. The potential reduction of equivalent carbon dioxide emissions was calculated using the total equivalent warming impact (TEWI) criterion in an effort to estimate the refrigeration impact on global warming. 12 refs., 4 tabs., 12 figs.

  5. Children should wear helmets while ice-skating: a comparison of skating-related injuries.

    Science.gov (United States)

    McGeehan, Jennifer; Shields, Brenda J; Smith, Gary A

    2004-07-01

    .9%, 52 of 56 cases), compared with injuries to skateboarders (3.6%, 1 of 28 cases) (RR: 13.96; 95% CI: 2.01-96.76), rollerskaters (63.4%, 59 of 93 cases) (RR: 1.46; 95% CI: 1.23-1.74), and in-line skaters (10.9%, 15 of 137 cases) (RR: 8.48; 95% CI: 5.23-13.75). The proportion of head injuries among ice-skaters in this study was greater than that observed for participants in other types of skating, for which helmet use is recommended and often required. Children should wear a helmet during recreational ice-skating. Mandatory helmet use by pediatric ice-skaters at indoor rinks should be implemented. Use of other types of protective equipment, such as wrist guards, knee pads, and elbow pads, should be considered for prevention of injuries to the extremities during ice-skating. Caution should be used when allowing young children to participate in recreational ice-skating. Additional research should be conducted in other populations, to corroborate these findings and to evaluate ice-skating safety recommendations for children.

  6. 30% of abatement of coldness needs + free re-heating at the skating rink of Chalons-en-Champagne; 30% de reduction des besoins de froid + rechauffage gratuit a la patinoire de Chalon-en-Champagne

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2005-12-01

    The skating rink of Chalons-en-Champagne (France) is equipped with a air treatment system based on the use of a sensible energy transfer battery which reduces by 30% the coldness needs for dehumidification. This process uses part of the heat released by the condensers to generate ice. The result is a 30% reduction of the installed power and a 40% reduction of energy consumptions with respect to standard air treatment solutions. (J.S.)

  7. Theory of ice-skating

    Science.gov (United States)

    Le Berre, Martine; Pomeau, Yves

    2015-10-01

    Almost frictionless skating on ice relies on a thin layer of melted water insulating mechanically the blade of the skate from ice. Using the basic equations of fluid mechanics and Stefan law, we derive a set of two coupled equations for the thickness of the film and the length of contact, a length scale which cannot be taken as its value at rest. The analytical study of these equations allows to define a small a-dimensional parameter depending on the longitudinal coordinate which can be neglected everywhere except close to the contact points at the front and the end of the blade, where a boundary layer solution is given. This solution provides without any calculation the order of magnitude of the film thickness, and its dependence with respect to external parameters like the velocity and mass of the skater and the radius of profile and bite angle of the blade, in good agreement with the numerical study. Moreover this solution also shows that a lubricating water layer of macroscopic thickness always exists for standard values of ice skating data, contrary to what happens in the case of cavitation of droplets due to thermal heating (Leidenfrost effect).

  8. Energy efficiency guide for ice arenas and curling rinks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    This document presented a set of guidelines which were designed to help operators of Manitoba's rinks and arenas by presenting practical ideas for saving money on energy in ice arenas, curling rinks, and similar recreational complexes. They cover a broad range of topics, from funding projects to details of specific components, and apply to new facilities, renovations, and day-to-day maintenance. These guidelines were based on a manual produced by the Saskatchewan Parks and Recreation Association in cooperation with the Saskatchewan Recreation Facility Association and sponsored by SaskPower. They represent an update of the 1991 manual to reflect improvements in technology, Manitoba Hydro's utility rates, and the requirements of Manitoba operators. The document presented guidelines and tips for understanding electrical and natural gas rates and structures; energy estimating methods; making a financial analysis; the building envelope; heating and ventilation; refrigeration; lighting; and heating effects of electrical equipment. Other guidelines presented came under the topics of operation and maintenance and project planning. Several appendices were also included, such as a glossary of terms; reference publications; energy calculations; power factor correction; heat pumps for rinks and arenas; and power smart programs for commercial buildings. refs., tabs., figs.

  9. The risks of injury in public ice skating.

    Science.gov (United States)

    Radford, P J; Williamson, D M; Lowdon, I M

    1988-01-01

    A prospective survey has been made of the injuries to members of the public attending a well established ice rink in a major city. Comparison is made with series in the literature reporting high levels of injuries, with corresponding demands on local hospital services, from newly established ice rinks. The main conclusion is that demands on hospital services have been markedly reduced for the well established rink, with corresponding savings in health service resources. PMID:3167509

  10. Ice rink installations working with natural refrigerants; Kunst-ijsbanen met NH3 en CO2, natuurlijker kan het niet

    Energy Technology Data Exchange (ETDEWEB)

    Berends, E. [Grenco, Den Bosch (Netherlands)

    2004-07-01

    In a growing number of countries it is not allowed anymore to use big amounts of ammonia in areas occupied by many people. So new skating halls with direct ammonia systems are not built anymore although those systems are the best solution, concerning ice quality and energy consumption. An indirect system NH3/glycol or brine uses circa 20% more energy. By using (H)CFC's instead of NH3 the energy consumption might even be higher. During the last years CO2 has proven itself not only as an excellent refrigerant but also as a very usable secondary refrigerant in stead of brines, etc. In this article the successful application of the newly developed NH3/CO2 system on an existing ice rink is described. [Dutch] Een overzicht wordt gegeven van de voordelen en de nadelen van verschillende koelmiddelen voor kunstijsbanen in Nederland (ammoniak, CO2, glycol)

  11. The effects of weighted skates on ice-skating kinematics, kinetics and muscular activity.

    Science.gov (United States)

    Mavor, Matthew P; Hay, Dean C; Graham, Ryan B

    2018-07-01

    Sport-specific resistance training, through limb loading, can be a complimentary training method to traditional resistance training by loading the working muscles during all phases of a specific movement. The purpose of this study was to examine the acute effects of skating with an additional load on the skate, using a skate weight prototype, on kinematics, kinetics, and muscle activation during the acceleration phase while skating on a synthetic ice surface. 10 male hockey skaters accelerated from rest (standing erect with knees slightly bent) under four non-randomized load conditions: baseline 1 (no weight), light (0.9 kg per skate), heavy (1.8 kg per skate), and baseline 2 (no weight). Skating with additional weight caused athletes to skate slower (p skates decreased skating velocity, but athletes maintained similar muscle activation profiles (magnitude and trends) with minor changes to their skating kinematics.

  12. The implementation of a municipal indoor ice skating helmet policy: effects on helmet use, participation and attitudes.

    Science.gov (United States)

    O'Mahony-Menton, Colleen; Willmore, Jacqueline; Russell, Katherine

    2015-12-01

    In Ottawa, between 2005 and 2009 there was an annual average of 47.2 head injuries due to ice skating in children and youth (1-19 years of age) requiring a visit to the emergency department, with the highest rates among those aged 5-14 years. Between 2002 and 2007, only 6% of children were wearing a helmet during ice skating when the head injury occurred. During indoor public skating sessions, 93% of children (skating helmet policy coupled with education and promotional activities on helmet use, participation and attitudes towards helmet use. An ice skating helmet policy for children (skating experience at indoor rinks during public skating sessions was developed, implemented and evaluated. Supportive activities such as discount coupons, promotional materials, a media launch, social marketing and staff training are described. The helmet policy was associated with increased helmet use for young children and for older children, youth and adults not included in the policy, without decreasing attendance to public skating sessions. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  13. Ice-skating and roller disco injuries in Dublin.

    Science.gov (United States)

    Horner, C.; McCabe, M. J.

    1984-01-01

    A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. Ice-skating fractures accounted for 40% of all injuries while roller skating fractures were only 14% of their total injuries. The majority of ice-skating fractures occurred in females. As a result of our study we recommended several preventative measures. Images p207-a p207-b PMID:6487948

  14. Ice-skating and roller disco injuries in Dublin.

    OpenAIRE

    Horner, C.; McCabe, M. J.

    1984-01-01

    A comparative study was carried out on a series of 72 ice-skating and 57 roller skating injuries over a sixteen month period. The average patient age was 20.5 years in the ice-skating group and 16.5 years in the roller skating group. Females predominated in both groups accounting for 72% of ice-skaters injured and 77% of roller skaters injured. Ice-skaters sustained more serious injuries than roller skaters as was evident from the significant difference in fracture numbers in the two groups. ...

  15. Environmental Loads of a Finnish indoor training iceskating rink in the Context of LCA

    International Nuclear Information System (INIS)

    Vaahterus, T.; Saari, A.

    2001-01-01

    In this study the environmental burdens generated by its essential building elements and systems of a typical new indoor training ice-skating rink during entire life cycle were calculated. The calculations were made by using a calculation method developed at Helsinki University of Technology at the department of Civil and Environmental Engineering, Construction Economics and Management. The developed method is based on LCA -methodology and follows the principle of the ISO 14040 Environmental Management standard. In the calculations the life cycle of the indoor training iceskating rink was divided in four main phases: new construction, maintenance and energy, repair, and demolition. In each life cycle phase all the material and energy flows and emissions were calculated. Almost all (99 %) of the building elements in the indoor training ice skating rink were made of non-renewable materials. Also the energy, consumed during the life cycle, was mainly (81 %) produced with non-renewable energy sources. The life cycle phases causing the most environmental loads were energy and new construction. The energy phase consumed 92 % of the total energy and produced 91 of the CO 2 equivalents and 74 % of the SO 2 equivalents. In the new-construction phase 6 % of the life cycle energy was consumed, and 64 % of the ethene equivalents were produced. In addition to these 79 % of the building materials were used in the new- construction phase. The calculations were also tested against the sensitivity to different presumption changes. Two kinds of presumptions were made: ones that could be influenced by project control and others which refer to the future of the building and could not be influenced by project control. The calculations of the environmental loads of the indoor training ice skating rink were most sensitive to changes in the usage profiles and indoor temperature. For example one of the usage profile increased the environmental loads of the indoor training ice skating rink

  16. Ice skating promotes postural control in children.

    Science.gov (United States)

    Keller, M; Röttger, K; Taube, W

    2014-12-01

    High fall rates causing injury and enormous financial costs are reported for children. However, only few studies investigated the effects of balance training in children and these studies did not find enhanced balance performance in postural (transfer) tests. Consequently, it was previously speculated that classical balance training might not be stimulating enough for children to adequately perform these exercises. Therefore, the aim of this study is to evaluate the influence of ice skating as an alternative form of balance training. Volunteers of an intervention (n = 17; INT: 13.1 ± 0.4 years) and a control group (n = 13; CON: 13.2 ± 0.3 years) were tested before and after training in static and dynamic postural transfer tests. INT participated in eight sessions of ice skating during education lessons, whereas CON participated in normal physical education. Enhanced balance performance was observed in INT but not in CON when tested on an unstable free-swinging platform (P skating in children. More importantly, participating children improved static and dynamic balance control in postural tasks that were not part of the training. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  17. Got Ice? Teaching Ice-Skating as a Lifelong Activity

    Science.gov (United States)

    Tarkinton, Brenda C.; Karp, Grace Goc

    2010-01-01

    With today's focus on the importance of lifelong physical activity, educators are increasingly offering a variety of such activities in their classes, as well as in before- and after-school programs. This article describes the benefits of offering ice skating as a challenging and rewarding lifetime activity, either before or after school or in…

  18. Energy efficient ice rink Thialf in Heerenveen, Netherlands; Ecosysteem maakt van Thialf een energiezuinige ijsbaan voor toptijden

    Energy Technology Data Exchange (ETDEWEB)

    Bijman, J.N.M. (ed.)

    2002-01-01

    The ice rink Thialf in Heerenveen, Netherlands, has been renovated, using a so-called Ecosystem. An overview is given of the installations, energy savings, improvement of the comfort and the main product: ice for world records in skating. [Dutch] Het ijsstadion Thialf heeft dit jaar een uitgebreide facelift ondergaan. De oude Heerenveense ijsvloer, bestaande uit 1200 m{sup 3} beton, is gesloopt en vernieuwd. In totaal is er nu 11.000 m{sup 2} ijs (400-meterbaan een tweede baan van 360 meter en een grabbelbaan). Het middenterrein is ter bescherming van de 400 meter baan met een tunnel te bereiken. Tevens is de vriesinstallatie en de klimaatinstallatie vervangen. Bertus Butter is als adviseur nauw betrokken bij de realisatie. Zijn opdracht was het realiseren van een energiebesparing van 40 tot 60% en zorgen voor wereldrecords. Andere doelstellingen bij de renovatie zijn het creeren van beter ijs en meer comfort. Door het ontwikkelen van een ecosysteem voor Thialf lijkt men in de doelstellingen te slagen. De energiebesparing en het comfort zijn zeker geslaagd, de wereldrecords zullen zich tijdens de topwedstrijden moeten melden.

  19. Pressure melting and ice skating

    Science.gov (United States)

    Colbeck, S. C.

    1995-10-01

    Pressure melting cannot be responsible for the low friction of ice. The pressure needed to reach the melting temperature is above the compressive failure stress and, if it did occur, high squeeze losses would result in very thin films. Pure liquid water cannot coexist with ice much below -20 °C at any pressure and friction does not increase suddenly in that range. If frictional heating and pressure melting contribute equally, the length of the wetted contact could not exceed 15 μm at a speed of 5 m/s, which seems much too short. If pressure melting is the dominant process, the water films are less than 0.08 μm thick because of the high pressures.

  20. Environmental Loads of a Finnish indoor training iceskating rink in the Context of LCA; Jaeaehallirakennuksen aiheuttamat ympaeristoekuormitukset

    Energy Technology Data Exchange (ETDEWEB)

    Vaahterus, T.; Saari, A.

    2001-07-01

    In this study the environmental burdens generated by its essential building elements and systems of a typical new indoor training ice-skating rink during entire life cycle were calculated. The calculations were made by using a calculation method developed at Helsinki University of Technology at the department of Civil and Environmental Engineering, Construction Economics and Management. The developed method is based on LCA -methodology and follows the principle of the ISO 14040 Environmental Management standard. In the calculations the life cycle of the indoor training iceskating rink was divided in four main phases: new construction, maintenance and energy, repair, and demolition. In each life cycle phase all the material and energy flows and emissions were calculated. Almost all (99 %) of the building elements in the indoor training ice skating rink were made of non-renewable materials. Also the energy, consumed during the life cycle, was mainly (81 %) produced with non-renewable energy sources. The life cycle phases causing the most environmental loads were energy and new construction. The energy phase consumed 92 % of the total energy and produced 91 of the CO{sub 2} equivalents and 74 % of the SO{sub 2} equivalents. In the new-construction phase 6 % of the life cycle energy was consumed, and 64 % of the ethene equivalents were produced. In addition to these 79 % of the building materials were used in the new- construction phase. The calculations were also tested against the sensitivity to different presumption changes. Two kinds of presumptions were made: ones that could be influenced by project control and others which refer to the future of the building and could not be influenced by project control. The calculations of the environmental loads of the indoor training ice skating rink were most sensitive to changes in the usage profiles and indoor temperature. For example one of the usage profile increased the environmental loads of the indoor training ice

  1. Technical fact sheets on the impacts of new energy efficiency technologies and measures in ice rinks

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

    This paper presents energy efficiency facts on ice rinks and arenas to advise and inform refrigeration and building professionals. The aim of the paper was to facilitate estimation and compare impacts of various energy efficiency measures and new technologies on the consumption of energy and the reduction of greenhouse gas (GHG) emissions. A computer-based tool modelling ice rink energy consumption was constructed based on DOE-2.1E software. The simulation tool was developed to study the sensitivity of various eco-energetic technologies applied to arenas. Results of the simulations have made it possible to construct 8 facts sheets, including information on simulated heat exchange; calculation of energy consumption for heating and refrigeration; the incorporation of several types of Heating Ventilation and Air Conditioning (HVAC) systems; and to show various strategies of operation. To account for the effects of ice within a building, calculation routines in the form of functional values were added. The model addressed the following parameters: climate; characteristics of the envelope; lighting power and intensity; temperature of the resurfacing water; ice sheet temperature; humidity level of the ice rink; fresh air intake; emissivity index of the ceiling above the ice sheet; refrigeration systems according to type, capacity, output and operation mode; capacity output and operation mode of the air heating system, including heat recovery from the refrigeration system; and capacity, output and operation mode of the domestic and resurfacing hot water heating system, including heat recovery from the refrigeration system. Fact sheets were presented for the type of technology; description; direct or indirect benefits; energy-savings potential; environmental impacts; specific comments from specialists; and a set of charts to facilitate comprehension. tabs., figs.

  2. The impact of ice-skating injuries on orthopaedic admissions in a regional hospital.

    LENUS (Irish Health Repository)

    Dillon, J P

    2012-02-03

    Since the opening of a temporary ice-rink in our hospital\\'s catchment area, we have observed an increase in patients requiring in-patient treatment for orthopaedic intervention. The authors performed a prospective analysis of all patients admitted to our unit over a one-month period. Epidemiological data, wearing of protective gear and skater experience were collected. Fracture type, treatment required, average length of hospital stay and number of days missed from work was also recorded. Ice-skating injuries accounted for 7.7% of our total admissions over the study period. There was a significant variation noted in the types of fracture sustained ranging from comminuted fractures of the radial head to spiral fractures of the tibia. The average length of hospital stay was 2.6 days and average time missed from work was 6.1 weeks. This paper highlights the potential serious injuries that can occur in ice-skating and their impact on admissions to our orthopaedic unit.

  3. A review of the physics of ice surface friction and the development of ice skating.

    Science.gov (United States)

    Formenti, Federico

    2014-01-01

    Our walking and running movement patterns require friction between shoes and ground. The surface of ice is characterised by low friction in several naturally occurring conditions, and compromises our typical locomotion pattern. Ice skates take advantage of this slippery nature of ice; the first ice skates were made more than 4000 years ago, and afforded the development of a very efficient form of human locomotion. This review presents an overview of the physics of ice surface friction, and discusses the most relevant factors that can influence ice skates' dynamic friction coefficient. It also presents the main stages in the development of ice skating, describes the associated implications for exercise physiology, and shows the extent to which ice skating performance improved through history. This article illustrates how technical and materials' development, together with empirical understanding of muscle biomechanics and energetics, led to one of the fastest forms of human powered locomotion.

  4. Thermal analysis and modeling of a swimming pool heating system by utilizing waste energy rejected from a chiller unit of an ice rink

    Directory of Open Access Journals (Sweden)

    Kuyumcu Muhammed Enes

    2017-01-01

    Full Text Available This study deals with the thermal analysis and modeling of a swimming pool heating system in which the waste energy rejected from the chiller unit of an ice rink is used as an energy source. The system consists of a swimming pool and an ice rink coupled by a chiller unit. The swimming pool and the ice rink both indoor types and were constructed in city of Gaziantep, Turkey. The thermal energy requirement for each section is determined by thermal analysis of each component of the system. Effects of different design parameters such as ceiling insulation thickness, ceiling emissivity, Carnot efficiency factor and size of the ice rink on the thermal energy requirements and coefficient of performance of the chiller unit are investigated. As a result of analyses of the system, the minimum ice rink area is determined in order to meet annual total heat energy demand of the olympic-sized swimming pool.

  5. Human locomotion on ice: the evolution of ice-skating energetics through history.

    Science.gov (United States)

    Formenti, Federico; Minetti, Alberto E

    2007-05-01

    More than 3000 years ago, peoples living in the cold North European regions started developing tools such as ice skates that allowed them to travel on frozen lakes. We show here which technical and technological changes determined the main steps in the evolution of ice-skating performance over its long history. An in-depth historical research helped identify the skates displaying significantly different features from previous models and that could consequently determine a better performance in terms of speed and energy demand. Five pairs of ice skates were tested, from the bone-skates, dated about 1800 BC, to modern ones. This paper provides evidence for the fact that the metabolic cost of locomotion on ice decreased dramatically through history, the metabolic cost of modern ice-skating being only 25% of that associated with the use of bone-skates. Moreover, for the same metabolic power, nowadays skaters can achieve speeds four times higher than their ancestors could. In the range of speeds considered, the cost of travelling on ice was speed independent for each skate model, as for running. This latter finding, combined with the accepted relationship between time of exhaustion and the sustainable fraction of metabolic power, gives the opportunity to estimate the maximum skating speed according to the distance travelled. Ice skates were probably the first human powered locomotion tools to take the maximum advantage from the biomechanical properties of the muscular system: even when travelling at relatively high speeds, the skating movement pattern required muscles to shorten slowly so that they could also develop a considerable amount of force.

  6. Skating rinks: a contribution to the discussion on using CO{sub 2} as a refrigerant; CO{sub 2} als Kaeltetraeger - ein Diskussionsbeitrag

    Energy Technology Data Exchange (ETDEWEB)

    Buehrer, B. W.

    2003-07-01

    This article examines the situation with regard to the use of carbon dioxide as a refrigerant for ice rinks instead of more risky and costly direct-evaporation ammonia installations. Tighter regulations on the operation of such ammonia-based installations and the advantages of CO{sub 2}-based systems are discussed. Although not poisonous, CO{sub 2} can present dangers if leaks occur as it is heavier than air and can lead to suffocation. Also, the energy consumption of CO{sub 2} refrigeration plants is compared with that of ammonia and glycol-based systems. The role played by other factors such as thermal insulation, good dehumidification systems and infra-red radiation shields are discussed. An installation in Zug, Switzerland, is briefly described that features cold-generation with ammonia and secondary distribution systems using CO{sub 2} and glycol for the main hall and the curling rinks respectively.

  7. Thermal analysis and modeling of a swimming pool heating system by utilizing waste energy rejected from a chiller unit of an ice rink

    OpenAIRE

    Kuyumcu Muhammed Enes; Yumrutaş Recep

    2017-01-01

    This study deals with the thermal analysis and modeling of a swimming pool heating system in which the waste energy rejected from the chiller unit of an ice rink is used as an energy source. The system consists of a swimming pool and an ice rink coupled by a chiller unit. The swimming pool and the ice rink both indoor types and were constructed in city of Gaziantep, Turkey. The thermal energy requirement for each section is determined by thermal analysis of each component of the system. Effec...

  8. Ice Skating: Special Olympics Sports Skills Instructional Program.

    Science.gov (United States)

    Special Olympics, Inc., Washington, DC.

    One of seven booklets on Special Olympics Sports Skills Instructional Programs, this guide presents teaching suggestions for ice skating coaches working with mentally retarded persons. An overview section introduces the sport and considers ideas for effective teaching. Goals, objectives, and benefits are considered along with information on…

  9. Average number of compressors in operation per day in 25 skating rinks of the City of Montreal; Nombre moyens de compresseurs par jour en fonction dans 25 arenas de la Ville de Montreal

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, C. [Ville de Montreal, PQ (Canada). Direction des Immeubles Gestion de l' Energie et du Genie Climatique

    2002-09-30

    Since the summer of 2001, 25 skating rinks from the territory of the old City of Montreal have been linked through a network to the remote management system. This initiative enables the people responsible for the skating rink to easily obtain statistics on the operation of refrigeration systems and to compile this information in the memory of a personal computer (PC). Each compressor system is equipped with a current transformer which acts as proof of monitored operation by the remote management system. Every minute, the compressors are asked in sequence to report on their status. The process by which the data is entered, filtered and analysed was explained and an example provided to better illustrate the concept. As a rule, management believes that it is possible to lower the power of existing refrigeration systems and to select new refrigeration systems according to the data acquired. Based on the results obtained so far, the power of some of the refrigeration systems has already been reduced by letting go one or two of the six refrigeration circuits of a skating rink. 2 tabs.

  10. An on-ice measurement approach to analyse the biomechanics of ice hockey skating.

    Directory of Open Access Journals (Sweden)

    Erica Buckeridge

    Full Text Available Skating is a fundamental movement in ice hockey; however little research has been conducted within the field of hockey skating biomechanics due to the difficulties of on-ice data collection. In this study a novel on-ice measurement approach was tested for reliability, and subsequently implemented to investigate the forward skating technique, as well as technique differences across skill levels. Nine high caliber (High and nine low caliber (Low hockey players performed 30 m forward skating trials. A 3D accelerometer was mounted to the right skate for the purpose of stride detection, with the 2nd and 6th strides defined as acceleration and steady-state, respectively. The activity of five lower extremity muscles was recorded using surface electromyography. Biaxial electro-goniometers were used to quantify hip and knee angles, and in-skate plantar force was measured using instrumented insoles. Reliability was assessed with the coefficient of multiple correlation, which demonstrated moderate (r>0.65 to excellent (r>0.95 scores across selected measured variables. Greater plantar-flexor muscle activity and hip extension were evident during acceleration strides, while steady state strides exhibited greater knee extensor activity and hip abduction range of motion (p<0.05. High caliber exhibited greater hip range of motion and forefoot force application (p<0.05. The successful implementation of this on-ice mobile measurement approach offers potential for athlete monitoring, biofeedback and training advice.

  11. An on-ice measurement approach to analyse the biomechanics of ice hockey skating.

    Science.gov (United States)

    Buckeridge, Erica; LeVangie, Marc C; Stetter, Bernd; Nigg, Sandro R; Nigg, Benno M

    2015-01-01

    Skating is a fundamental movement in ice hockey; however little research has been conducted within the field of hockey skating biomechanics due to the difficulties of on-ice data collection. In this study a novel on-ice measurement approach was tested for reliability, and subsequently implemented to investigate the forward skating technique, as well as technique differences across skill levels. Nine high caliber (High) and nine low caliber (Low) hockey players performed 30 m forward skating trials. A 3D accelerometer was mounted to the right skate for the purpose of stride detection, with the 2nd and 6th strides defined as acceleration and steady-state, respectively. The activity of five lower extremity muscles was recorded using surface electromyography. Biaxial electro-goniometers were used to quantify hip and knee angles, and in-skate plantar force was measured using instrumented insoles. Reliability was assessed with the coefficient of multiple correlation, which demonstrated moderate (r>0.65) to excellent (r>0.95) scores across selected measured variables. Greater plantar-flexor muscle activity and hip extension were evident during acceleration strides, while steady state strides exhibited greater knee extensor activity and hip abduction range of motion (p<0.05). High caliber exhibited greater hip range of motion and forefoot force application (p<0.05). The successful implementation of this on-ice mobile measurement approach offers potential for athlete monitoring, biofeedback and training advice.

  12. Performance of a swimming pool heating system by utilizing waste energy rejected from an ice rink with an energy storage tank

    International Nuclear Information System (INIS)

    Kuyumcu, Muhammed Enes; Tutumlu, Hakan; Yumrutaş, Recep

    2016-01-01

    Highlights: • An analytical model of the system, and a computational program were developed. • Transient behavior of the water in the buried energy storage tank was simulated. • Effects of various system parameters on the system performance were investigated. • Long period performance of the system was analyzed and obtained periodic condition. • Optimum ice rink size is determined for a semi-Olympic size swimming pool heating. - Abstract: This study deals with determining the long period performance of a swimming pool heating system by utilizing waste heat energy that is rejected from a chiller unit of ice rink and subsequently stored in an underground thermal energy storage (TES) tank. The system consists of an ice rink, a swimming pool, a spherical underground TES tank, a chiller and a heat pump. The ice rink and the swimming pool are both enclosed and located in Gaziantep, Turkey. An analytical model was developed to obtain the performance of the system using Duhamel’s superposition and similarity transformation techniques. A computational model written in MATLAB program based on the transient heat transfer is used to obtain the annual variation of the ice rink and the swimming pool energy requirements, the water temperature in the TES tank, COP, and optimum ice rink size depending on the different ground, TES tank, chiller, and heat pump characteristics. The results obtained from the analysis indicate that 6–7 years’ operational time span is necessary to obtain the annual periodic operation condition. In addition, an ice rink with a size of 475 m"2 gives the optimum performance of the system with a semi-Olympic size swimming pool (625 m"2).

  13. Skating start propulsion: three-dimensional kinematic analysis of elite male and female ice hockey players.

    Science.gov (United States)

    Shell, Jaymee R; Robbins, Shawn M K; Dixon, Philippe C; Renaud, Philippe J; Turcotte, René A; Wu, Tom; Pearsall, David J

    2017-09-01

    The forward skating start is a fundamental skill for male and female ice hockey players. However, performance differences by athlete's sex cannot be fully explained by physiological variables; hence, other factors such as skating technique warrant examination. Therefore, the purpose of this study was to evaluate the body movement kinematics of ice hockey skating starts between elite male and female ice hockey participants. Male (n = 9) and female (n = 10) elite ice hockey players performed five forward skating start accelerations. An 18-camera motion capture system placed on the arena ice surface captured full-body kinematics during the first seven skating start steps within 15 meters. Males' maximum skating speeds were greater than females. Skating technique sex differences were noted: in particular, females presented ~10° lower hip abduction throughout skating stance as well as ~10° greater knee extension at initial ice stance contact, conspicuously followed by a brief cessation in knee extension at the moment of ice contact, not evident in male skaters. Further study is warranted to explain why these skating technique differences exist in relation to factors such as differences in training, equipment, performance level, and anthropometrics.

  14. Simulation of the energy consumption of a skating rink using DOE-2.1E software; Simulation de la consommation d'energie d'un arena a l'aide du logiciel DOE-2.1E

    Energy Technology Data Exchange (ETDEWEB)

    Zmeureanu, R. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering; Zelaya, E.M.; Giguere, D. [Natural Resources Canada, Varennes, PQ (Canada). CANMET Energy Diversification Laboratory

    2002-07-01

    The vast majority of skating rinks in Quebec are over 20 years old, and there is a requirement to retrofit their refrigeration systems. In this paper, the authors presented the approach developed to simulate the thermal phenomena that occur within a skating rink in Canada. The simulation tool was designed by the Canada Centre for Mineral and Energy Technology (CANMET) Energy Technology Centre in cooperation with Concordia University to study the sensitivity of various eco energy technologies with a specific application to skating rinks. The originality of this work stems from the use of DOE-2.1E calculation software to simulate heat transfer. The structure of the simulation tool was presented, including a brief description of the calculation algorithms that were developed, as well as some preliminary results obtained during the validation phase. 8 refs., 1 tab., 4 figs.

  15. Analysis of motion in speed skating

    Science.gov (United States)

    Koga, Yuzo; Nishimura, Tetsu; Watanabe, Naoki; Okamoto, Kousuke; Wada, Yuhei

    1997-03-01

    A motion on sports has been studied by many researchers from the view of the medical, psychological and mechanical fields. Here, we try to analyze a speed skating motion dynamically for an aim of performing the best record. As an official competition of speed skating is performed on the round rink, the skating motion must be studied on the three phases, that is, starting phase, straight and curved course skating phase. It is indispensable to have a visual data of a skating motion in order to analyze kinematically. So we took a several subject's skating motion by 8 mm video cameras in order to obtain three dimensional data. As the first step, the movement of the center of gravity of skater (abbreviate to C. G.) is discussed in this paper, because a skating motion is very complicated. The movement of C. G. will give an information of the reaction force to a skate blade from the surface of ice. We discuss the discrepancy of several skating motion by studied subjects. Our final goal is to suggest the best skating form for getting the finest record.

  16. Instructional Basics: Oppelt Standard Method of Therapeutic and Recreational Ice Skating.

    Science.gov (United States)

    Oppelt, Kurt

    Detailed in the booklet is the standard ice skating method and considered are the benefits of therapeutic ice skating for the handicapped and aged. Values for the mentally retarded and physically handicapped are seen to include physiological (such as increased flexibility and improved posture), psychological (including satifaction and enhanced…

  17. Snowball Earth: Skating on Thin Ice?

    Science.gov (United States)

    Roberson, A. L.; Stout, A. M.; Pollard, D.; Kasting, J. F.

    2011-12-01

    There is evidence of at least two intervals of widespread glaciation during the late Neoproterozoic (600-800 Myr ago), which are commonly referred to as "Snowball Earth" episodes. The global nature of these events is indicated by the fact that glacial deposits are found at low paleolatitudes during this time. Models of a global glacial event have produced a variety of solutions at low latitudes: thick ice, thin ice, slushball, and open ocean . The latter two models are similar, except that the slushball model has its ice-line at higher latitudes. To be viable, a model has to be able to account for the survival of life through the glaciations and also explain the existence of cap carbonates and other glacial debris deposited at low latitudes. The "thick-ice" model is not viable because kilometers of ice prevent the penetration of light necessary for the photosynthetic biota below. The "slushball" model is also not viable as it does not allow the formation of cap carbonates. The "thin-ice" model has been discussed previously and can account for continuation of photosynthetic life and glacial deposits at low paleolatitudes. The recently proposed "open-ocean" or "Jormungand" model also satisfies these requirements. What is it, though, that causes some models to produce thin ice near the equator and others to have open water there? We examine this question using a zonally symmetric energy balance climate model (EBM) with flowing sea glaciers to determine what parameter ranges produce each type of solution.

  18. The most modern skating rink in Switzerland - the St. Jakob Arena in Basle; Das modernste Eissportstadion der Schweiz: St. Jakob Arena Basel

    Energy Technology Data Exchange (ETDEWEB)

    Frey, P.

    2002-07-01

    This comprehensive article describes the cold generation system used in the ice-sports arena in Basle, Switzerland, that is also used in summer for events, exhibitions etc. The system, which uses a two-circuit system to provide the cooling for the ice rink, is described, including its innovative change-over system for use as a heat pump to provide heating energy for hot-water, space heating and ventilation. The concept, which features ammonia-based primary cold generation and a water-glycol mixture for the secondary cold distribution, is described in detail and compared with earlier systems that used direct-evaporation ammonia systems. In particular the safety-relevant aspects are emphasised. Technical details on the installation are presented in table form. In particular, the solving of condensation problems in the arena - humidity is brought in by the ice preparation and by outside air - are discussed with respect to the ventilation and air-drying system installed in the ice-sport arena.

  19. Comparison of skating kinetics and kinematics on ice and on a synthetic surface.

    Science.gov (United States)

    Stidwill, T J; Pearsall, David; Turcotte, Rene

    2010-03-01

    The recent popularization and technological improvements of synthetic or artificial ice surfaces provide an attractive alternative to real ice in venues where the latter is impractical to install. Potentially, synthetic ice (SI) may be installed in controlled laboratory settings to permit detailed biomechanical analysis of skating manoeuvres. Unknown, however, is the extent to which skating on SI replicates skating on traditional ice (ICE). Hence, the purpose of this study was to compare kinetic and kinematic forward skating parameters between SI and ICE surfaces. With 11 male hockey players, a portable strain gauge system adhered to the outside of the skate blade holder was used to measure skate propulsive force synchronized with electrogoniometers for tracking dynamic knee and ankle movements during forward skating acceleration. In general, the kinetic and kinematic variables investigated in this study showed minimal differences between the two surfaces (P > 0.06), and no individual variable differences were identified between the two surfaces (P > or = 0.1) with the exception of greater knee extension on SI than ICE (15.2 degrees to 11.0 degrees; P skating, and thus offer the potential for valid analogous conditions for in-lab testing and training.

  20. A building technical management system optimizes the energy recovery in a swimming pool-skating rink complex; Une GTB optimise la recuperation d'energie d'un complexe piscine-patinoire

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2003-04-01

    The municipal skating rink of La Roche-sur-Yon (France) is supplied by a direct expansion refrigerating system. The energy recovered from this system allows to heat the sport complex made of a 25 m swimming pool and of a ludic pool. A technical management system ensures the control and management of the overall technical equipments. The automation of the system has permitted to optimize the energy costs which have remained practically unchanged since 20 years, even after the extension of the main pool and the increase of the number of visitors. (J.S.)

  1. Peak incidence of distal radius fractures due to ice skating on natural ice in The Netherlands

    NARCIS (Netherlands)

    van Lieshout, Arno P. W.; van Manen, Christiaan J.; du Pré, Karel J.; Kleinlugtenbelt, Ydo V.; Poolman, Rudolf W.; Goslings, J. Carel; Kloen, Peter

    2010-01-01

    An increase of distal radius fractures was seen in 2009 when an extended cold spell allowed natural ice skating in Amsterdam. This resulted in overload of our Emergency Departments and operating rooms. This study reports patient and fracture characteristics of these injuries. We also determined

  2. The effect of a heated skate blade on the ice surface

    Energy Technology Data Exchange (ETDEWEB)

    Hache, A. [Moncton Univ., NB (Canada). Dept. of Physics and Astronomy

    2007-05-15

    A new hockey skate using a heated blade, called the Therma Blade, cuts ice friction by half, thereby improving skating performance but has created questions about melting and damage of the ice surface. This paper discussed the effect of the heated skate blade on the ice surface. The paper discussed the thermal power produced by the Therma Blade skate, the ice melting capacity of the therma blade, and the ice temperature profile around the heated blade. It also examined the power dissipation by friction comparing the cold versus the heated blade. Units and definitions as well as conversion factors were also presented in appendix format. Constants and technical specifications were listed in an appendix. It was concluded that the maximum melting capacity of the therma blade is 0.7 grams of ice per skate per minute. This is the upper limit as set by the laws of physics, and this requires the skate to be completely static over ice at 0 degrees Celsius and all the power drawn by the battery to reach the ice friction force. 5 refs., 1 tab., 2 figs.

  3. Skating mechanics of change-of-direction manoeuvres in ice hockey players.

    Science.gov (United States)

    Fortier, Antoine; Turcotte, René A; Pearsall, David J

    2014-11-01

    Ice hockey requires rapid transitions between skating trajectories to effectively navigate about the ice surface. Player performance relates in large part to effective change-of-direction manoeuvres, but little is known about how those skills are performed mechanically and the effect of equipment design on them. The purpose of this study was to observe the kinetics involved in those manoeuvres as well as to compare whether kinetic differences may result between two skate models of varying ankle mobility. Eight subjects with competitive ice hockey playing experience performed rapid lateral (90°) left and right change-of-direction manoeuvres. Kinetic data were collected using force strain gauge transducers on the blade holders of the skates. Significantly greater forces were applied by the outside skate (50-70% body weight, %BW) in comparison to the inside skate (12-24%BW, p Skate model and turn direction had no main effect, though significant mixed interactions between leg side (inside/outside) with skate model or turn direction (p skating change-of-direction tasks.

  4. Analisys and energy saving measures of kastvallen ice hockey rink arena

    OpenAIRE

    Igual Bueno, Mario; Bielsa Azcona, José Enrique

    2011-01-01

    Nowadays efficiency measures are more and more important because the price of the energy is increasing every year. Moreover, saving energy it is also important for decrease the environmental impact. Kastvallen is a hockey arena built in 1997 that cools the hockey rink with electric compressors. The changing rooms are heating by using district heating. Actually the total invoice of electricity is above the 800000 SEK. Meanwhile the district heating invoice reaches the 60000SE...

  5. The Use of Simulation Training to Accelerate the Rate of Forward Ice Skating Skill Acquisition

    Directory of Open Access Journals (Sweden)

    Nathan J Washington

    2016-04-01

    Full Text Available Background: Australia’s interest and participation in ice hockey is increasing, however a lack of access to facilities means familiarity with this sport is limited, and so too is the facilitation of skill development within an ecologically valid context. Objective: While numerous methods may be employed to address this, one resource which remains relatively unexplored is the StrideDeck Treadmill, therefore the purpose of this study was to investigate the effectiveness of this equipment with specific reference to the biomechanical changes for skating ability. Methods: N = 16 male athletes (Mage = 15.0 ± 0.76 yrs from a junior league competition participated in this intervention based study. n = 9 were assigned to the training intervention (StrideDeck once a week, while the control group (n = 7 continued their normal training routines. Further, monthly sprint tests both on the StrideDeck and an on-ice protocol were conducted to track progress via kinematic analysis. Results: Data analysis revealed no significant overall effects for on-ice sprint skating performance after StrideDeck training; however there were significant kinematic differences between StrideDeck and ice conditions. Conclusions: Therefore while the StrideDeck may have merit in regard to physiological paramters, the results of this study do not support its use as a skill acquisition tool in regard to increasing skating ability. Keywords: Simulation training, skill acquisition, treadmill, ice skating, ice hockey skating, ice skating stride

  6. Evaluation of an adaptive ice skating programme for children with disabilities.

    Science.gov (United States)

    Fragala-Pinkham, Maria A; Dumas, Helene M; Boyce, Megan; Peters, Christine Y; Haley, Stephen M

    2009-08-01

    To describe an adaptive ice skating programme designed by paediatric therapists. Twenty-two children, ages 5-12 years, with developmental disabilities participated in this once per week skating programme lasting 6 weeks. Ice skating instructors led the group lessons, while university student coaches provided individualized assistance to the children. The programme was evaluated using a summative evaluation design. Outcomes included participant attendance, incidence of injuries, skating skills and parent and student coach survey data. On average, participants attended 83% of the sessions and one minor injury was reported. Participants' parents were very satisfied with the programme and reported improvements in their child's skating skills, leg strength, endurance, balance, self-esteem/confidence and ability to participate in a group. Student coaches also reported high levels of satisfaction with this programme and reported similar improvements in the children they coached. The programme appeared promising, but may require minor modifications.

  7. Instrumented figure skating blade for measuring on-ice skating forces

    Science.gov (United States)

    Acuña, S. A.; Smith, D. M.; Robinson, J. M.; Hawks, J. C.; Starbuck, P.; King, D. L.; Ridge, S. T.; Charles, S. K.

    2014-12-01

    Competitive figure skaters experience substantial, repeated impact loading during jumps and landings. Although these loads, which are thought to be as high as six times body weight, can lead to overuse injuries, it is not currently possible to measure these forces on-ice. Consequently, efforts to improve safety for skaters are significantly limited. Here we present the development of an instrumented figure skating blade for measuring forces on-ice. The measurement system consists of strain gauges attached to the blade, Wheatstone bridge circuit boards, and a data acquisition device. The system is capable of measuring forces in the vertical and horizontal directions (inferior-superior and anterior-posterior directions, respectively) in each stanchion with a sampling rate of at least 1000 Hz and a resolution of approximately one-tenth of body weight. The entire system weighs 142 g and fits in the space under the boot. Calibration between applied and measured force showed excellent agreement (R > 0.99), and a preliminary validation against a force plate showed good predictive ability overall (R ≥ 0.81 in vertical direction). The system overestimated the magnitude of the first and second impact peaks but detected their timing with high accuracy compared to the force plate.

  8. An ice rink refrigeration system based on CO{sub 2} as secondary fluid in copper tubes

    Energy Technology Data Exchange (ETDEWEB)

    Shahzad, Khuram [Royal Inst. of Technology, Stockholrn (Sweden). Dept. of Energy Technology

    2006-06-15

    This report is a study of the use of copper tubes with CO{sub 2} as heat transfer fluid in ice rink applications. Copper tubes can be rolled rather easily up to the required length which decreases installation cost and simplifies the procedure. A test ice rink was built at IUC Ref Centre, Katrineholm with copper tubes. FEMLAB and EES are two softwares that were used for analysis. The comparison between 12.7 mm diameter copper tubes with and without plastic foil cover, 9.5 mm diameter copper tubes with and without plastic foil cover, 21.3 mm diameter steel pipes and 25 mm diameter plastic pipes is presented in the report. The reason to have plastic foil over copper tubes is to avoid the minor risk of chemical corrosion. Furthermore the foil serves as mechanical wear protection as well, which in this case could appear if rubbing would occur due to thermal expansion and contraction. It is found that 12.7 mm copper tube with plastic foil is good choice in terms of heat transfer. At rated heat flux of 100 W/m{sup 2} and with a pitch of 100 mm, it is 0.18 deg C better than 9.5 mm copper tube with plastic foil. This report includes the investigation which shows that there is no danger of movement of copper tubes inside the rink bed due to thermal expansion and contraction during operation. It also includes the comparison of average Friedel pressure drop model and average homogeneous pressure drop model with experimental results. Average Friedel pressure drop method gave good results. It predicted 20 to 25 % higher pressure drop at lower CR and about 60 % at higher CR than the experimental results for 120 meter long and 12.7 mm diameter copper tubes. 120 meter long copper tubes are good choice; as header can be placed on short side of the ice rink. It will reduce the header length and connections to half. FEMLAB modelling for conduction heat transfer gave good results and can be used as a tool for design and optimization. The optimization of the pitch of the copper tubes

  9. Injury severity in ice skating: an epidemiologic analysis using a standardised injury classification system.

    Science.gov (United States)

    Ostermann, Roman C; Hofbauer, Marcus; Tiefenböck, Thomas M; Pumberger, Matthias; Tiefenböck, Michael; Platzer, Patrick; Aldrian, Silke

    2015-01-01

    Although injuries sustained during ice skating have been reported to be more serious than other forms of skating, the potential injury risks are often underestimated by skating participants. The purpose of this study was to give a descriptive overview of injury patterns occurring during ice skating. Special emphasis was put on injury severity by using a standardised injury classification system. Over a six month period, all patients treated with ice-skating-related injuries at Europe's largest hospital were included. Patient demographics were collected and all injuries categorised according to the Abbreviated Injury Scale (AIS) 2005. A descriptive statistic and logistic regression analysis was performed. Three hundred and forty-one patients (134 M, 207 F) were included in this study. Statistical analysis revealed that age had a significant influence on injury severity. People > 50 years had a higher risk of sustaining a more severe injury according to the AIS compared with younger skaters. Furthermore, the risk of head injury was significantly lower for people aged between 18 and 50 years than for people  50 years than for people aged between 18 and 50 years (p = 0.04). The severity of ice-skating injuries is associated with the patient's age, showing more severe injuries in older patients. Awareness should be raised among the public and physicians about the risks associated with this activity in order to promote further educational interventions and the use of protective gear.

  10. Observed decreases in the Canadian outdoor skating season due to recent winter warming

    International Nuclear Information System (INIS)

    Damyanov, Nikolay N; Mysak, Lawrence A; Damon Matthews, H

    2012-01-01

    Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada. (letter)

  11. Observed decreases in the Canadian outdoor skating season due to recent winter warming

    Science.gov (United States)

    Damyanov, Nikolay N.; Damon Matthews, H.; Mysak, Lawrence A.

    2012-03-01

    Global warming has the potential to negatively affect one of Canada’s primary sources of winter recreation: hockey and ice skating on outdoor rinks. Observed changes in winter temperatures in Canada suggest changes in the meteorological conditions required to support the creation and maintenance of outdoor skating rinks; while there have been observed increases in the ice-free period of several natural water bodies, there has been no study of potential trends in the duration of the season supporting the construction of outdoor skating rinks. Here we show that the outdoor skating season (OSS) in Canada has significantly shortened in many regions of the country as a result of changing climate conditions. We first established a meteorological criterion for the beginning, and a proxy for the length of the OSS. We extracted this information from daily maximum temperature observations from 1951 to 2005, and tested it for significant changes over time due to global warming as well as due to changes in patterns of large-scale natural climate variability. We found that many locations have seen a statistically significant decrease in the OSS length, particularly in Southwest and Central Canada. This suggests that future global warming has the potential to significantly compromise the viability of outdoor skating in Canada.

  12. Physiological correlates of skating performance in women's and men's ice hockey.

    Science.gov (United States)

    Gilenstam, Kajsa M; Thorsen, Kim; Henriksson-Larsén, Karin B

    2011-08-01

    The purpose of the current investigation was to identify relationships between physiological off-ice tests and on-ice performance in female and male ice hockey players on a comparable competitive level. Eleven women, 24 ± 3.0 years, and 10 male ice hockey players, 23 ± 2.4 years, were tested for background variables: height, body weight (BW), ice hockey history, and lean body mass (LBM) and peak torque (PT) of the thigh muscles, VO2peak and aerobic performance (Onset of Blood Lactate Accumulation [OBLA], respiratory exchange ratio [RER1]) during an incremental bicycle ergometer test. Four different on-ice tests were used to measure ice skating performance. For women, skating time was positively correlated (p skating time was positively correlated to VO2peak (L O2·min(-1)) in the Acceleration test. The male group had significantly higher physiological test values in all variables (absolute and relative to BW) but not in relation to LBM. Selected off-ice tests predict skating performance for women but not for men. The group of women was significantly smaller and had a lower physiological performance than the group of men and were slower in the on-ice performance tests. However, gender differences in off-ice variables were reduced or disappeared when values were related to LBM, indicating a similar capacity of producing strength and aerobic power in female and male hockey players. Skating performance in female hockey players may be improved by increasing thigh muscle strength, oxygen uptake, and relative muscle mass.

  13. Morphological, Physiological and Skating Performance Profiles of Male Age-Group Elite Ice Hockey Players

    Directory of Open Access Journals (Sweden)

    Allisse Maxime

    2017-08-01

    Full Text Available The purpose of this study was to describe the evolution of morphological, physiological and skating performance profiles of elite age-group ice hockey players based on repeated measures spread over one season. In addition, the results of fitness tests and training programs performed in off-ice conditions and their relationship with skating performance were analyzed. Eighteen high level age-group ice hockey players (13.1 ± 0.6 years were assessed off and on-ice at the beginning and at the end of the hockey season. A third evaluation was also conducted at the beginning of the following hockey season. The players were taller, heavier, and showed bone breadths and muscle girths above the reference population of the same age. Muscular variables improved significantly during and between the two hockey seasons (p < 0.05. However, maximal aerobic power improved only during the off-season. All skating performance tests exhibited significant enhancements during the hockey season, but not during the off-season where some degradation was observed. Finally, weak observed variances (generally <20% of the explained variance between physiological variables measured off-ice and on-ice skating performance tests indicated important gaps, both in the choice of the off-ice assessment tools as well as in training methods conventionally used. The reflection on the best way to assess and train hockey players certainly deserves to be continued.

  14. Relationship between Physiological Off-Ice Testing, On-Ice Skating, and Game Performance in Division I Women's Ice Hockey Players.

    Science.gov (United States)

    Boland, Michelle; Miele, Emily M; Delude, Katie

    2017-10-07

    The purpose was to identify off-ice testing variables that correlate to skating and game performance in Division I collegiate women ice hockey players. Twenty female, forward and defensive players (19.95 ± 1.35 yr) were assessed for weight, height, percent fat mass (%FAT), bone mineral density, predicted one repetition maximum (RM) absolute and relative (REL%) bench press (BP) and hex bar deadlift (HDL), lower body explosive power, anaerobic power, countermovement vertical jump (CMJ), maximum inspiratory pressure (MIP), and on-ice repeated skate sprint (RSS) performance. The on-ice RSS test included 6 timed 85.6 m sprints with participants wearing full hockey equipment; fastest time (FT), average time (AT) and fatigue index (FI) for the first length skate (FLS; 10 m) and total length skate (TLS; 85.6 m) were used for analysis. Game performance was evaluated with game statistics: goals, assists, points, plus-minus, and shots on goal (SOG). Correlation coefficients were used to determine relationships. Percent fat mass was positively correlated (p Game performance in women ice hockey players may be enhanced by greater MIP, repeat acceleration ability, and mode-specific training. Faster skating times were associated with lower %FAT. Skating performance in women ice hockey players may be enhanced by improving body composition, anaerobic power, and both lower and upper body strength in off-ice training.

  15. Multiple Off-Ice Performance Variables Predict On-Ice Skating Performance in Male and Female Division III Ice Hockey Players.

    Science.gov (United States)

    Janot, Jeffrey M; Beltz, Nicholas M; Dalleck, Lance D

    2015-09-01

    The purpose of this study was to determine if off-ice performance variables could predict on-ice skating performance in Division III collegiate hockey players. Both men (n = 15) and women (n = 11) hockey players (age = 20.5 ± 1.4 years) participated in the study. The skating tests were agility cornering S-turn, 6.10 m acceleration, 44.80 m speed, modified repeat skate, and 15.20 m full speed. Off-ice variables assessed were years of playing experience, height, weight and percent body fat and off-ice performance variables included vertical jump (VJ), 40-yd dash (36.58m), 1-RM squat, pro-agility, Wingate peak power and peak power percentage drop (% drop), and 1.5 mile (2.4km) run. Results indicated that 40-yd dash (36.58m), VJ, 1.5 mile (2.4km) run, and % drop were significant predictors of skating performance for repeat skate (slowest, fastest, and average time) and 44.80 m speed time, respectively. Four predictive equations were derived from multiple regression analyses: 1) slowest repeat skate time = 2.362 + (1.68 x 40-yd dash time) + (0.005 x 1.5 mile run), 2) fastest repeat skate time = 9.762 - (0.089 x VJ) - (0.998 x 40-yd dash time), 3) average repeat skate time = 7.770 + (1.041 x 40-yd dash time) - (0.63 x VJ) + (0.003 x 1.5 mile time), and 4) 47.85 m speed test = 7.707 - (0.050 x VJ) - (0.01 x % drop). It was concluded that selected off-ice tests could be used to predict on-ice performance regarding speed and recovery ability in Division III male and female hockey players. Key pointsThe 40-yd dash (36.58m) and vertical jump tests are significant predictors of on-ice skating performance specific to speed.In addition to 40-yd dash and vertical jump, the 1.5 mile (2.4km) run for time and percent power drop from the Wingate anaerobic power test were also significant predictors of skating performance that incorporates the aspect of recovery from skating activity.Due to the specificity of selected off-ice variables as predictors of on-ice performance, coaches can

  16. Validation of the FAST skating protocol to predict aerobic power in ice hockey players.

    Science.gov (United States)

    Petrella, Nicholas J; Montelpare, William J; Nystrom, Murray; Plyley, Michael; Faught, Brent E

    2007-08-01

    Few studies have reported a sport-specific protocol to measure the aerobic power of ice hockey players using a predictive process. The purpose of our study was to validate an ice hockey aerobic field test on players of varying ages, abilities, and levels. The Faught Aerobic Skating Test (FAST) uses an on-ice continuous skating protocol on a course measuring 160 feet (48.8 m) using a CD to pace the skater with a beep signal to cross the starting line at each end of the course. The FAST incorporates the principle of increasing workload at measured time intervals during a continuous skating exercise. Step-wise multiple regression modelling was used to determine the estimate of aerobic power. Participants completed a maximal aerobic power test using a modified Bruce incremental treadmill protocol, as well as the on-ice FAST. Normative data were collected on 406 ice hockey players (291 males, 115 females) ranging in age from 9 to 25 y. A regression to predict maximum aerobic power was developed using body mass (kg), height (m), age (y), and maximum completed lengths of the FAST as the significant predictors of skating aerobic power (adjusted R2 = 0.387, SEE = 7.25 mL.kg-1.min-1, p < 0.0001). These results support the application of the FAST in estimating aerobic power among male and female competitive ice hockey players between the ages of 9 and 25 years.

  17. Morphological, Physiological and Skating Performance Profiles of Male Age-Group Elite Ice Hockey Players.

    Science.gov (United States)

    Allisse, Maxime; Sercia, Pierre; Comtois, Alain-Steve; Leone, Mario

    2017-09-01

    The purpose of this study was to describe the evolution of morphological, physiological and skating performance profiles of elite age-group ice hockey players based on repeated measures spread over one season. In addition, the results of fitness tests and training programs performed in off-ice conditions and their relationship with skating performance were analyzed. Eighteen high level age-group ice hockey players (13.1 ± 0.6 years) were assessed off and on-ice at the beginning and at the end of the hockey season. A third evaluation was also conducted at the beginning of the following hockey season. The players were taller, heavier, and showed bone breadths and muscle girths above the reference population of the same age. Muscular variables improved significantly during and between the two hockey seasons (p skating performance tests exhibited significant enhancements during the hockey season, but not during the off-season where some degradation was observed. Finally, weak observed variances (generally skating performance tests indicated important gaps, both in the choice of the off-ice assessment tools as well as in training methods conventionally used. The reflection on the best way to assess and train hockey players certainly deserves to be continued.

  18. Development of Automated Tracking System with Active Cameras for Figure Skating

    Science.gov (United States)

    Haraguchi, Tomohiko; Taki, Tsuyoshi; Hasegawa, Junichi

    This paper presents a system based on the control of PTZ cameras for automated real-time tracking of individual figure skaters moving on an ice rink. In the video images of figure skating, irregular trajectories, various postures, rapid movements, and various costume colors are included. Therefore, it is difficult to determine some features useful for image tracking. On the other hand, an ice rink has a limited area and uniform high intensity, and skating is always performed on ice. In the proposed system, an ice rink region is first extracted from a video image by the region growing method, and then, a skater region is extracted using the rink shape information. In the camera control process, each camera is automatically panned and/or tilted so that the skater region is as close to the center of the image as possible; further, the camera is zoomed to maintain the skater image at an appropriate scale. The results of experiments performed for 10 training scenes show that the skater extraction rate is approximately 98%. Thus, it was concluded that tracking with camera control was successful for almost all the cases considered in the study.

  19. Multiple Off-Ice Performance Variables Predict On-Ice Skating Performance in Male and Female Division III Ice Hockey Players

    Directory of Open Access Journals (Sweden)

    effrey M. Janot, Nicholas M. Beltz, Lance D. Dalleck

    2015-09-01

    Full Text Available The purpose of this study was to determine if off-ice performance variables could predict on-ice skating performance in Division III collegiate hockey players. Both men (n = 15 and women (n = 11 hockey players (age = 20.5 ± 1.4 years participated in the study. The skating tests were agility cornering S-turn, 6.10 m acceleration, 44.80 m speed, modified repeat skate, and 15.20 m full speed. Off-ice variables assessed were years of playing experience, height, weight and percent body fat and off-ice performance variables included vertical jump (VJ, 40-yd dash (36.58m, 1-RM squat, pro-agility, Wingate peak power and peak power percentage drop (% drop, and 1.5 mile (2.4km run. Results indicated that 40-yd dash (36.58m, VJ, 1.5 mile (2.4km run, and % drop were significant predictors of skating performance for repeat skate (slowest, fastest, and average time and 44.80 m speed time, respectively. Four predictive equations were derived from multiple regression analyses: 1 slowest repeat skate time = 2.362 + (1.68 x 40-yd dash time + (0.005 x 1.5 mile run, 2 fastest repeat skate time = 9.762 - (0.089 x VJ - (0.998 x 40-yd dash time, 3 average repeat skate time = 7.770 + (1.041 x 40-yd dash time - (0.63 x VJ + (0.003 x 1.5 mile time, and 4 47.85 m speed test = 7.707 - (0.050 x VJ - (0.01 x % drop. It was concluded that selected off-ice tests could be used to predict on-ice performance regarding speed and recovery ability in Division III male and female hockey players.

  20. Relationship between body composition, leg strength, anaerobic power, and on-ice skating performance in division I men's hockey athletes.

    Science.gov (United States)

    Potteiger, Jeffrey A; Smith, Dean L; Maier, Mark L; Foster, Timothy S

    2010-07-01

    The purpose of this study was to examine relationships between laboratory tests and on-ice skating performance in division I men's hockey athletes. Twenty-one men (age 20.7 +/- 1.6 years) were assessed for body composition, isokinetic force production in the quadriceps and hamstring muscles, and anaerobic muscle power via the Wingate 30-second cycle ergometer test. Air displacement plethysmography was used to determine % body fat (%FAT), fat-free mass (FFM), and fat mass. Peak torque and total work during 10 maximal effort repetitions at 120 degrees .s were measured during concentric muscle actions using an isokinetic dynamometer. Muscle power was measured using a Monark cycle ergometer with resistance set at 7.5% of body mass. On-ice skating performance was measured during 6 timed 89-m sprints with subjects wearing full hockey equipment. First length skate (FLS) was 54 m, and total length skate (TLS) was 89 m with fastest and average skating times used in the analysis. Correlation coefficients were used to determine relationships between laboratory testing and on-ice performance. Subjects had a body mass of 88.8 +/- 7.8 kg and %FAT of 11.9 +/- 4.6. First length skate-Average and TLS-Average skating times were moderately correlated to %FAT ([r = 0.53; p = 0.013] and [r = 0.57; p = 0.007]) such that a greater %FAT was related to slower skating speeds. First length skate-Fastest was correlated to Wingate percent fatigue index (r = -0.48; p = 0.027) and FLS-Average was correlated to Wingate peak power per kilogram body mass (r = -0.43; p = 0.05). Laboratory testing of select variables can predict skating performance in ice hockey athletes. This information can be used to develop targeted and effective strength and conditioning programs that will improve on-ice skating speed.

  1. Dehumidification by dessiccant regenerated by natural gas at the Campeau ice rink in Gatineau; La deshumidification par dessiccant regenere par le gaz naturel a l'Arena Campeau de Gatineau

    Energy Technology Data Exchange (ETDEWEB)

    Lajoie, S.

    2003-03-01

    As air quality gains in importance, dehumidification by dessiccant represents an interesting technological solution, especially in ice rinks where bad air quality (carbon monoxide) is not unknown. Contrary to conventional technologies, dehumidification by dessiccant allows to maintain adequate levels of air quality and optimum humidity levels. Three major advantages are: improved user comfort, the building structure is protected from corrosion, and superior air quality levels are achieved. The document first provided the reader with a brief overview of conventional mechanical dehumidification systems before discussing dehumidification by natural gas dessiccant. A quick historical review of the Campeau ice rink in Gatineau, Quebec was provided, including results obtained. The article concluded by indicating that the technology offers interesting potential for ice rinks. Energy savings are made possible through the utilization of this technology, and improves revenues by stretching operations for longer periods. 1 tab., 1 fig.

  2. The effect of ice skating on psychological well-being and sleep quality of children with visual or hearing impairment.

    Science.gov (United States)

    Dursun, Onur Burak; Erhan, Süleyman Erim; Ibiş, Esra Özhan; Esin, Ibrahim Selcuk; Keleş, Sadullah; Şirinkan, Ahmet; Yörük, Özgür; Acar, Ethem; Beyhun, Nazim Ercument

    2015-01-01

    Physical exercise and sports have a key role in preventing physical and psychiatric problems in children. However, children with a disability often experience difficulty participating in physical activity due to a lack of suitable opportunities. Participation in an accessible sport is particularly important for these children, but studies examining which sports are beneficial for which disability groups are rare. In this study, we assessed the effects of ice skating on the psychological well-being, self-concept, and sleep quality of children with hearing or visual impairment. Forty students (20 visually impaired and 20 hearing impaired) aged 8-16 were included in a regular ice skating programme for three months. We examined the sleep quality, self-concept, and behavioural and emotional states of the children before and after participating in the programme. There was a significant improvement in self-concept, behavioural and emotional problems, and sleep quality (p sleep quality (p = 0.019) and emotional problem scores (p = 0.000) of the visually impaired children improved; self-concept, peer relations and hyperactivity scores of these children worsened (p sport alternatives that gives children the opportunity to exercise and have fun together. The results of this study revealed that regular ice skating programmes may have positive effects on the psychological well-being of children with hearing impairment. Despite some positive effects, caution must be use when including visually impaired children in ice skating programmes. Generalization of the study's outcomes is limited as the study group were residential students enrolled in special education institutions for children who are blind or deaf. Ice skating is a community-based sport and a popular leisure activity that can also have benefits for people with disabilities. Ice skating and children with hearing impairment: Self-concept, behavioural and emotional problems, and sleep quality of the children

  3. The energy management manual for arena and rink operators

    Energy Technology Data Exchange (ETDEWEB)

    Raymer, M. [Saskatchewan Parks and Recreation Assoc., Regina, SK (Canada); White, T. [Office of Energy Conservation, Regina, SK (Canada); Kozoriz, D.F. [SaskPower, Regina, SK (Canada); Norman, D. [SaskPower, Saskatoon, SK (Canada)

    2006-08-15

    In an era when energy costs often rise faster than the community tax base, energy conservation plays a key role in ensuring that skating arenas are able to continue operating. This manual on energy management for arena and rink operators includes current technologies and practices that reduce operating costs. It is meant to help in the training and education of all facility operators. Since fossil fuels are the main source of electrical generation in Saskatchewan, reducing energy consumption directly reduces greenhouse gas emissions to the environment. This manual included a brief introduction to energy calculations for operators of rinks and arenas. The calculations can be performed for the heat loss that occurs in winter and the amount of heat input needed to maintain temperatures. It was recommended that the more difficult calculation of estimating the amount of cooling required for ice making should be done by qualified consultants. The 10 sections of the manual addressed the issues of: (1) electrical and natural gas rates, (2) meters and electrical inventory, (3) making a financial analysis, (4) the building envelope, (5) heating and ventilation, (6) refrigeration, (7) lighting, (8) heating effects of electrical equipment, (9) operation and maintenance, and, (10) project planning. The manual also presented methods to improve the power factor by adding relatively inexpensive components, such as capacitors, to lower electricity bills by as much as 20 per cent. A review of geo-exchange systems for rinks and arenas was included along with heat recovery from refrigeration systems and financial assistance for commercial, institutional and municipal buildings. refs., tabs., figs.

  4. Laboratory- and field-based testing as predictors of skating performance in competitive-level female ice hockey.

    Science.gov (United States)

    Henriksson, Tommy; Vescovi, Jason D; Fjellman-Wiklund, Anncristine; Gilenstam, Kajsa

    2016-01-01

    The purpose of this study was to examine whether field-based and/or laboratory-based assessments are valid tools for predicting key performance characteristics of skating in competitive-level female hockey players. Cross-sectional study. Twenty-three female ice hockey players aged 15-25 years (body mass: 66.1±6.3 kg; height: 169.5±5.5 cm), with 10.6±3.2 years playing experience volunteered to participate in the study. The field-based assessments included 20 m sprint, squat jump, countermovement jump, 30-second repeated jump test, standing long jump, single-leg standing long jump, 20 m shuttle run test, isometric leg pull, one-repetition maximum bench press, and one-repetition maximum squats. The laboratory-based assessments included body composition (dual energy X-ray absorptiometry), maximal aerobic power, and isokinetic strength (Biodex). The on-ice tests included agility cornering s-turn, cone agility skate, transition agility skate, and modified repeat skate sprint. Data were analyzed using stepwise multivariate linear regression analysis. Linear regression analysis was used to establish the relationship between key performance characteristics of skating and the predictor variables. Regression models (adj R (2)) for the on-ice variables ranged from 0.244 to 0.663 for the field-based assessments and from 0.136 to 0.420 for the laboratory-based assessments. Single-leg tests were the strongest predictors for key performance characteristics of skating. Single leg standing long jump alone explained 57.1%, 38.1%, and 29.1% of the variance in skating time during transition agility skate, agility cornering s-turn, and modified repeat skate sprint, respectively. Isokinetic peak torque in the quadriceps at 90° explained 42.0% and 32.2% of the variance in skating time during agility cornering s-turn and modified repeat skate sprint, respectively. Field-based assessments, particularly single-leg tests, are an adequate substitute to more expensive and time

  5. Relationship Between Skating Economy and Performance During a Repeated-Shift Test in Elite and Subelite Ice Hockey Players.

    Science.gov (United States)

    Lamoureux, Nicholas R; Tomkinson, Grant R; Peterson, Benjamin J; Fitzgerald, John S

    2018-04-01

    Lamoureux, NR, Tomkinson, GR, Peterson, BJ, and Fitzgerald, JS. Relationship between skating economy and performance during a repeated-shift test in elite and subelite ice hockey players. J Strength Cond Res 32(4): 1109-1113, 2018-The purpose of this study was to determine the importance of skating economy to fatigue during repeated high-intensity efforts of a simulated ice hockey shift. Forty-five collegiate and Junior A male ice hockey players (aged 18-24 years) performed a continuous graded exercise test using a skate treadmill. Breath-by-breath data for oxygen consumption (V[Combining Dot Above]O2) and respiratory exchange ratio were collected and used to derive energy expenditure (EE) averaged over the final 10 seconds of each stage. Economy was determined as the slope of the regression line relating V[Combining Dot Above]O2 and EE against skating speed separately. Participants also completed 8 bouts of maximal ice skating through a course designed to simulate typical shift, with timing gates determining first half, second half, and total fatigue decrement, calculated by a percent decrement score. Partial correlation was used to determine the association between economy measures and decrement during the repeated-shift test. Twenty-six participants met inclusion criteria and were included in data analysis. Skating economy measures (both relative V[Combining Dot Above]O2 and EE) were very likely moderate positive correlates of total fatigue decrement (r [95% confidence interval]: V[Combining Dot Above]O2, 0.46 [0.09, 0.72] and EE, 0.44, [0.06, 0.71]) but not with first or second gate decrement. Our results indicate that skating economy plays an important role in fatigue resistance over repeated on-ice sprints designed to simulate a typical shift. This supports the use of technical skating coaching and training techniques to enhance skating economy as a means of improving ice hockey performance.

  6. Establishing the Test-Retest Reliability & Concurrent Validity for the Repeat Ice Skating Test (RIST) in Adolescent Male Ice Hockey Players

    Science.gov (United States)

    Power, Allan; Faught, Brent E.; Przysucha, Eryk; McPherson, Moira; Montelpare, William

    2012-01-01

    In this study the authors examine the test-retest reliability and concurrent validity of the Repeat Ice Skating Test (RIST). This was an on-ice field anaerobic test that measured average peak power and was validated with 3 anaerobic lab tests: (a) vertical jump, (b) the Margaria-Kalamen stair test, and (c) the Wingate Anaerobic Test. The…

  7. Body movements during the off-ice execution of back spins in figure skating.

    Science.gov (United States)

    Mapelli, Andrea; Rodano, Renato; Fiorentini, Angelo; Giustolisi, Andrea; Sidequersky, Fernanda V; Sforza, Chiarella

    2013-10-01

    Using an optoelectronic motion capture system, we quantitatively assessed the arrangement of body segments and the displacement of the horizontal projection of the center of mass (CM) in seven skaters performing off-ice back spins on a rotating device (spinner). The position of the CM at the beginning of the spins was not a determining factor, but its rapid stabilization towards the center of the spinner, together with the achievement of a stable arrangement of trunk and limbs, was crucial to get the dynamic equilibrium, necessary for a lasting performance. At full spinning, however, there was an indicative variety of individual body postures. A final deceleration, associable with the loss of body equilibrium, was detected in the last spin of most of skaters. In conclusion, the current investigation demonstrated that the off-ice execution of back spin, a critical movement of ice skating, can be measured in laboratory, thus providing quantitative information to both the skaters and the coaches. The analysis is not invasive, and it may be proposed also for longitudinal evaluations of skating and postural training. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Skating on thin ice: surface chemistry under interstellar conditions

    Science.gov (United States)

    Fraser, H.; van Dishoeck, E.; Tielens, X.

    Solid CO2 has been observed towards both active star forming regions and quiescent clouds (Gerakines et. al. (1999)). The high abundance of CO2 in the solid phase, and its low abundance in the gas phase, support the idea that CO2 is almost exclusively formed in the solid state. Several possible formation mechanisms have been postulated (Ruffle &Herbst (2001): Charnley &Kaufman (2000)), and the detection of CO2 towards quiescent sources such as Elias 16 (Whittet et. al. (1998)) clearly suggests that CO2 can be produced in the absence of UV or electron mediated processes. The most likely route is via the surface reactions between O atoms, or OH radicals, and CO. The tools of modern surface- science offer us the potential to determine many of the physical and chemical attributes of icy interstellar grain mantles under highly controlled conditions, that closely mimic interstellar environments. The Leiden Surface Reaction Simulation Device ( urfreside) combines UHV (UltraS High Vacuum) surface science techniques with an atomic beam to study chemical reactions occurring on the SURFACE and in the BULK of interstellar ice grain mimics. By simultaneously combining two or more surface analysis techniques, the chemical kinetics, reaction mechanisms and activation energies can be determined directly. The experiment is aimed at identifying the key barrierless reactions and desorption pathways on and in H2 O and CO ices under interstellar conditions. The results from traditional HV (high vacuum) and UHV studies of the CO + O and CO + OH reactions will be presented in this paper. Charnley, S.B., & Kaufman, M.J., 2000, ApJ, 529, L111 Gerakines, P.A., 1999, ApJ, 522, 357 Ruffle, D.P., & Herbst, E., 2001, MNRAS, 324, 1054 Whittet, D.C.B., et.al., 1998, ApJ, 498, L159

  9. Skating on Thin Ice: Evolution of Conservation in Energy Policy

    Science.gov (United States)

    Gibbons, Jack

    2009-05-01

    Why are we physicists so often drawn into the nexus of energy policy and governance? There are several explanations. First, we are quite accustomed to this phenomenon of ``cause and effect,'' so we instinctively examine those two ends as well as the connections between them (i.e., what happens between a lump of coal and a light bulb). That way of thinking makes energy production and consumption intiminately connected and ``conservation'' naturally becomes a technological strategy rather than an appendage. Strangely, however, ``conservation'' in our society (called ``The Cowboy Economy'' by economist Kenneth Boulding) has been widely interpreted as competitive with supply and ridiculed as only a minor option, entailing denial of an amenity. After nearly a half-century of dialogue, innovation, and frustration, the rationality of what I call the ``physics'' perspective seems to have come of age. The evolution of relevant science and technology and public policy has advanced markedly, reflected and sustained at the national level by a succession of organizations. The Congressional Office of Technology Assessment, the Federal Office of Energy Conservation, the Federal Energy Administration, the U.S. Department of Energy, and the Office of Science and Technology Policy. Not surprisingly, physicists continue to play key roles in the inculcation of science and analysis into the policy and governance. This requires, as implied by C.P. Snow, a bridging and strengthening of the thin ice between science and society. We still have a long road to travel.

  10. Laboratory- and field-based testing as predictors of skating performance in competitive-level female ice hockey

    Directory of Open Access Journals (Sweden)

    Henriksson T

    2016-08-01

    Full Text Available Tommy Henriksson,1,2 Jason D Vescovi,3 Anncristine Fjellman-Wiklund,4 Kajsa Gilenstam1 1Sport Medicine Unit, Department of Community Medicine and Rehabilitation, 2The National Graduate School of Gender Studies, Umeå University, Umeå, Sweden; 3Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada; 4Physiotherapy Unit, Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden Objectives: The purpose of this study was to examine whether field-based and/or laboratory-based assessments are valid tools for predicting key performance characteristics of skating in competitive-level female hockey players.Design: Cross-sectional study.Methods: Twenty-three female ice hockey players aged 15–25 years (body mass: 66.1±6.3 kg; height: 169.5±5.5 cm, with 10.6±3.2 years playing experience volunteered to participate in the study. The field-based assessments included 20 m sprint, squat jump, countermovement jump, 30-second repeated jump test, standing long jump, single-leg standing long jump, 20 m shuttle run test, isometric leg pull, one-repetition maximum bench press, and one-repetition maximum squats. The laboratory-based assessments included body composition (dual energy X-ray absorptiometry, maximal aerobic power, and isokinetic strength (Biodex. The on-ice tests included agility cornering s-turn, cone agility skate, transition agility skate, and modified repeat skate sprint. Data were analyzed using stepwise multivariate linear regression analysis. Linear regression analysis was used to establish the relationship between key performance characteristics of skating and the predictor variables.Results: Regression models (adj R2 for the on-ice variables ranged from 0.244 to 0.663 for the field-based assessments and from 0.136 to 0.420 for the laboratory-based assessments. Single-leg tests were the strongest predictors for key performance characteristics of skating. Single leg standing

  11. Updating the Skating Multistage Aerobic Test and Correction for V[Combining Dot Above]O2max Prediction Using a New Skating Economy Index in Elite Youth Ice Hockey Players.

    Science.gov (United States)

    Allisse, Maxime; Bui, Hung Tien; Léger, Luc; Comtois, Alain-Steve; Leone, Mario

    2018-05-07

    Allisse, M, Bui, HT, Léger, L, Comtois, A-S, and Leone, M. Updating the skating multistage aerobic test and correction for V[Combining Dot Above]O2max prediction using a new skating economy index in elite youth ice hockey players. J Strength Cond Res XX(X): 000-000, 2018-A number of field tests, including the skating multistage aerobic test (SMAT), have been developed to predict V[Combining Dot Above]O2max in ice hockey players. The SMAT, like most field tests, assumes that participants who reach a given stage have the same oxygen uptake, which is not usually true. Thus, the objectives of this research are to update the V[Combining Dot Above]O2 values during the SMAT using a portable breath-by-breath metabolic analyzer and to propose a simple index of skating economy to improve the prediction of oxygen uptake. Twenty-six elite hockey players (age 15.8 ± 1.3 years) participated in this study. The oxygen uptake was assessed using a portable metabolic analyzer (K4b) during an on-ice maximal shuttle skate test. To develop an index of skating economy called the skating stride index (SSI), the number of skating strides was compiled for each stage of the test. The SMAT enabled the prediction of the V[Combining Dot Above]O2max (ml·kg·min) from the maximal velocity (m·s) and the SSI (skating strides·kg) using the following regression equation: V[Combining Dot Above]O2max = (14.94 × maximal velocity) + (3.68 × SSI) - 24.98 (r = 0.95, SEE = 1.92). This research allowed for the update of the oxygen uptake values of the SMAT and proposed a simple measure of skating efficiency for a more accurate evaluation of V[Combining Dot Above]O2max in elite youth hockey players. By comparing the highest and lowest observed SSI scores in our sample, it was noted that the V[Combining Dot Above]O2 values can vary by up to 5 ml·kg·min. Our results suggest that skating economy should be included in the prediction of V[Combining Dot Above]O2max to improve prediction accuracy.

  12. Mood after various brief exercise and sport modes: aerobics, hip-hop dancing, ice skating, and body conditioning.

    Science.gov (United States)

    Kim, Sungwoon; Kim, Jingu

    2007-06-01

    To investigate the potential psychological benefits of brief exercise and sport activities on positive mood alterations, 45 Korean high school and 232 undergraduate students enrolled in physical education and stress management classes voluntarily participated and were randomly assigned to one of four activities: aerobic exercise, body conditioning, hip-hop dancing, and ice skating. Mood changes from before to after exercise (2 pm to 3 pm) were measured based on a Korean translation of the Subjective Exercise Experiences Scale. The findings suggested that the aerobics and hip-hop dancing groups rated positive well-being higher than the body conditioning and ice skating groups. Immediately after exercise, psychological distress was rated lower in the aerobics and hip-hop dancing groups, as was fatigue.

  13. Effects of a recreational ice skating program on the functional mobility of a child with cerebral palsy.

    Science.gov (United States)

    Walsh, Sharon Fleming; Scharf, Michael G

    2014-04-01

    The purpose of this study was to describe the effects of an ice skating program on the ambulation, strength, posture and balance of a child with cerebral palsy (CP). The subject was a five-year-old female with a diagnosis of CP and a Gross Motor Classification System level of III. The subject was a slow and labored household ambulator on level surfaces with bilateral forearm crutches and bilateral ankle foot orthoses. She was unable to transfer to and from the floor to stand independently, stand unsupported or take steps independently. Until the initiation of this study she was receiving physical therapy services 2×/week. For the purpose of this study she participated in a 1 h/week local ice skating program for people with disabilities for a period of four months. The subject displayed clinically significant improvements in functional mobility including: improved standing posture; independent transfer to and from the floor to stand; maintenance of independent standing for 3 min; independent walking for 10 feet; increased ability to isolate extremity musculature; increased strength; improved Gross Motor Function Measure-88 scores and increased endurance. A subsequent testing session four months after the ice skating program had ended displayed declines but not to pre-intervention levels in muscle strength; ability to transfer to and from the floor to stand; functional mobility and standing balance. The results appear to suggest that the participation in an ice skating program clinically improved this child's functional mobility. Further research needs to be done with regard to physical recreational programs and the benefit they can have on the function of children with activity limitations.

  14. Analysis of High-Intensity Skating in Top-Class Ice Hockey Match-Play in Relation to Training Status and Muscle Damage.

    Science.gov (United States)

    Lignell, Erik; Fransson, Dan; Krustrup, Peter; Mohr, Magni

    2018-05-01

    Lignell, E, Fransson, D, Krustrup, P, and Mohr, M. Analysis of high-intensity skating in top-class ice hockey match-play in relation to training status and muscle damage. J Strength Cond Res 32(5): 1303-1310, 2018-We examined high-intensity activities in a top-class ice-hockey game and the effect of training status. Male ice-hockey players (n = 36) from the National Hockey League participated. Match analysis was performed during a game and physical capacity was assessed by a submaximal Yo-Yo Intermittent Recovery Ice-hockey test, level 1 (YYIR1-IHSUB). Venous blood samples were collected 24-hour post-game to determine markers of muscle damage. Players performed 119 ± 8 and 31 ± 3 m·min of high intensity and sprint skating, respectively, during a game. Total distance covered was 4,606 ± 219 m (2,260-6,749 m), of which high-intensity distance was 2042 ± 97 m (757-3,026 m). Sprint-skating speed was 5-8% higher (p ≤ 0.05) in periods 1 and 2 vs. period 3 and overtime. Defensemen (D) covered 29% more (p ≤ 0.05) skating in total than forwards (F) and were on the ice 47% longer. However, F performed 54% more (p ≤ 0.05) high-intensity skating per minute than defensemen. Plasma creatine kinase (CK) was 338 ± 45 (78-757) U·L 24-hour post-game. Heart rate loading during YYIR1-IHSUB correlated inversely (p ≤ 0.05) to the frequency of high-intensity skating bouts (r = -0.55) and V[Combining Dot Above]O2max (r = -0.85) and positively to post-game CK (r = 0.49; p ≤ 0.05). In conclusion, ice hockey is a multiple-sprint sport that provokes fatigue in the latter half of a game. Forwards perform more intense skating than defensemen. Moreover, high-intensity game activities during top-class ice hockey are correlated with cardiovascular loading during a submaximal skating test. Taken together, training of elite ice-hockey players should improve the ability for repeated high-intensity skating, and testing should include the YYIR1-IHSUB test as an indicator for ice

  15. A Comparative Analysis of Selected Mechanical Aspects of the Ice Skating Stride.

    Science.gov (United States)

    Marino, G. Wayne

    This study quantitatively analyzes selected aspects of the skating strides of above-average and below-average ability skaters. Subproblems were to determine how stride length and stride rate are affected by changes in skating velocity, to ascertain whether the basic assumption that stride length accurately approximates horizontal movement of the…

  16. Implementation of an all-ages mandatory helmet policy for ice skating.

    Science.gov (United States)

    Thibault-Halman, Ginette; Fenerty, Lynne; Wheadon-Hore, Kathie; Walling, Simon; Cusimano, Michael D; Clarke, David B

    2015-12-01

    Ice skaters sustain a significant number of head injuries each winter. We are the first to implement an all-ages helmet policy at a university-based Canadian arena. We report our experience from a cross-sectional observational study as well as the policy's consequences on helmet use and skating participation. Educational programming was provided prior to policy implementation. Observations of helmet use, falls and skater demographics were conducted prior to education/implementation and after policy implementation. The number of skaters observed was essentially unchanged by the policy; 361 skaters were observed pre-implementation, while 358 were observed post-implementation during the same number of observation-hours. Pre-implementation, helmet use ranged from 97% among children under 12 to 10% among adults; post-implementation use in all skaters was 99%. Falls were observed among all age groups, with preponderance among those aged 4-12. An all-ages helmet policy was successful both in achieving helmet use among all skaters and in maintaining participation rates. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  17. Three-dimensional kinematics of the knee and ankle joints for three consecutive push-offs during ice hockey skating starts.

    Science.gov (United States)

    Lafontaine, Dany

    2007-09-01

    Little biomechanical research has been conducted recently on hockey skating despite the sport's worldwide appeal. One reason for this lack of biomechanical knowledge stems from the difficulty of collecting data. The lack of accuracy, the disputable realism of treadmills, and the large field of view required are some of the technical challenges that have to be overcome. The main objective of the current study was to improve our knowledge of the joint kinematics during the skating stroke. A second objective was to improve the data collection system we developed and the third was to establish if a kinematic progression exists in the hockey skating stroke similar to that in speed skating. Relative motions at the knee and ankle joints were computed using a joint coordinate system approach. The differences at the knee joints in push-offs indicated that the skating skill was progressively changing with each push-off. The relative stability of the ankle angles can be attributed to the design of the skate boots, which have recently become very rigid. Further research on ice hockey skating is warranted and should include more skaters and investigate the effect various starting strategies and variations in equipment have on skaters' performance.

  18. Three-dimensional kinematics of the lower limbs during forward ice hockey skating.

    Science.gov (United States)

    Upjohn, Tegan; Turcotte, René; Pearsall, David J; Loh, Jonathan

    2008-05-01

    The objectives of the study were to describe lower limb kinematics in three dimensions during the forward skating stride in hockey players and to contrast skating techniques between low- and high-calibre skaters. Participant motions were recorded with four synchronized digital video cameras while wearing reflective marker triads on the thighs, shanks, and skates. Participants skated on a specialized treadmill with a polyethylene slat bed at a self-selected speed for 1 min. Each participant completed three 1-min skating trials separated by 5 min of rest. Joint and limb segment angles were calculated within the local (anatomical) and global reference planes. Similar gross movement patterns and stride rates were observed; however, high-calibre participants showed a greater range and rate of joint motion in both the sagittal and frontal planes, contributing to greater stride length for high-calibre players. Furthermore, consequent postural differences led to greater lateral excursion during the power stroke in high-calibre skaters. In conclusion, specific kinematic differences in both joint and limb segment angle movement patterns were observed between low- and high-calibre skaters.

  19. Importance of ice for the «White Olympics»

    Directory of Open Access Journals (Sweden)

    A. F. Renkel

    2016-01-01

    Full Text Available Organization of any winter Olympic game, often called as «White Olympics», requires interfacing between sports, technology and glaciology. History of the Olympic winter games and the Norwegian figure skater Sonia Henie, first and the only three-time Olympic champion (1928, 1932, 1936 in ladies figure skating, is presented in the article. Leaving the amateurish sport, Henie became a Hollywood star of the ballet on ice. She was introduced to the inventor Frank Zamboni, who created the ice re-surfacer (the ice-cleaning combine to restore the ice on skating rinks. Using the combine by Henie during her tours in the United States served to advertise this machine, and the name Zamboni had become a trademark for machines «Zamboni».

  20. THE COMPETITIVE DEMANDS OF ELITE MALE RINK HOCKEY

    Directory of Open Access Journals (Sweden)

    Aladino Fernández

    2013-06-01

    Full Text Available The aim of this study was to simulate the activity pattern of rink hockey by designing a specific skate test (ST to study the energy expenditure and metabolic responses to this intermittent high-intensity exercise and extrapolate the results from the test to competition. Six rink hockey players performed, in three phases, the 20-metre multi-stage shuttle roller skate test, a tournament match and the ST. Heart rate was monitored in all three phases. Blood lactate, oxygen consumption, ventilation and respiratory exchange ratio were also recorded during the ST. Peak HR was 190.7±7.2 beats · min-1. There were no differences in peak HR between the three tests. Mean HR was similar between the ST and the match (86% and 87% of HRmax, respectively. Peak and mean ventilation averaged 111.0±8.8 L · min-1 and 70.3±14.0 L · min-1 (60% of VEmax, respectively. VO2max was 56.3±8.4 mL · kg-1 · min-1, and mean oxygen consumption was 40.9±7.9 mL · kg-1 · min-1 (70% of VO2max. Maximum blood lactate concentration was 7.2±1.3 mmol · L-1. ST yielded an energy expenditure of 899.1±232.9 kJ, and energy power was 59.9±15.5 kJ · min-1. These findings suggest that the ST is suitable for estimating the physiological demands of competitive rink hockey, which places a heavy demand on the aerobic and anaerobic systems, and requires high energy consumption.

  1. Injuries in synchronized skating.

    Science.gov (United States)

    Dubravcic-Simunjak, S; Kuipers, H; Moran, J; Simunjak, B; Pecina, M

    2006-06-01

    Synchronized skating is a relatively new competitive sport and data about injuries in this discipline are lacking. Therefore the purpose of this study was to investigate the frequency and pattern of acute and overuse injuries in synchronized skaters. Before and during the World Synchronized Skating Championship 2004, a questionnaire inquiring about the frequency of injuries in this skating discipline was given to 23 participating teams. A total of 514 women and 14 men senior skaters completed the questionnaires (100 % response). Two hundred and eighteen (42.4 %) female and 6 (42.9 %) male skaters had suffered from acute injuries during their synchronized skating career. As some skaters had suffered from more than one injury, the total number of acute injuries in females was 398 and in males 14. In female skaters 19.8 % of acute injuries were head injuries, 7.1 % trunk, 33.2 % upper, and 39.9 % lower extremity injuries. In male skaters 14.3 % were head injuries, 28.6 % upper, and 57.1 % lower extremity injuries, with no report of trunk injuries. Sixty-nine female and 2 male skaters had low back problems and 112 female and 2 male skaters had one or more overuse syndromes during their skating career. Of 155 overuse injuries in female skaters, 102 (65.8 %) occurred during their figure skating career, while 53 injuries (34.2 %) only occurred when they skated in synchronized skating teams. In male skaters, out of 5 overuse injuries, 4 (80 %) occurred in their figure skating career, while 1 (20 %) occurred during their synchronized skating career. Out of the total of 412 injuries, 338 (82 %) occurred during on-ice practice, while 74 (18 %) happened during off-ice training. Ninety-one (26.9 %) acute injures occurred while practicing individual elements, and 247 (73.1 %) on-ice injuries occurred while practicing different team elements. We conclude that injuries in synchronized skating should be of medical concern due to an increasing number of acute injuries, especially

  2. Differences in Lower Body Kinematics during Forward Treadmill Skating Between Two Different Hockey Skate Designs

    Directory of Open Access Journals (Sweden)

    Mike R. Hellyer

    2016-01-01

    Full Text Available Purpose: The purpose of this study was to investigate the differences in ankle flexibility and skating technique between a traditional hockey skate boot and a hockey skate boot with a flexible rear tendon guard. Skating technique was further investigated at different speeds to give insight on how skating technique alters as skating speed is increased. Methods: Eight elite hockey players were selected for the present study, which was conducted while skating on an Endless Ice Skating Treadmill.  Variables were recorded using a three-camera setup and measured from video records at five selected treadmill speeds using the Dartfish Team Pro v6 software.  Kinematic variables were then compared between the two skate designs with a doubly multivariate repeated measures design.  Statistical significance was set at p<0.05.  Results: Post hoc univariate tests comparing skate designs displayed significant increases in plantar flexion, plantar flexion angular velocity, hip extension, hip extension angular velocity, stride length, and stride velocity while participants were wearing the skates that had a flexible rear tendon guard.  Significant increases were also displayed in plantar flexion, plantar flexion angular velocity, knee extension, knee extension angular velocity, hip extension, hip extension angular velocity, hip abduction range of motion, hip abduction angular velocity, stride width, stride length, and stride velocity as the treadmill speed increased. There was also a significant decrease in the time the skate was in contact with the treadmill as treadmill speed increased. Conclusion: The results suggested that while skating forward, hockey players could improve their hockey skating technique by using hockey skates that have a flexible rear tendon guard.  This flexible tendon guard improved skating technique by increasing the time of force application to the ice by increasing the range of ankle plantar flexion during propulsion of the

  3. The coefficient of friction, particularly of ice

    International Nuclear Information System (INIS)

    Mills, Allan

    2008-01-01

    The static and dynamic coefficients of friction are defined, and values from 0.3 to 0.6 are quoted for common materials. These drop to about 0.15 when oil is added as a lubricant. Water ice at temperatures not far below 0 °C is remarkable for low coefficients of around 0.05 for static friction and 0.04–0.02 for dynamic friction, but these figures increase as the temperature diminishes. Reasons for the slipperiness of ice are summarized, but they are still not entirely clear. One hypothesis suggests that it is related to the transient formation of a lubricating film of liquid water produced by frictional heating. If this is the case, some composition melting a little above ambient temperatures might provide a skating rink that did not require expensive refrigeration. Various compositions have been tested, but an entirely satisfactory material has yet to be found

  4. Vitamin D status and V[combining dot above]O2peak during a skate treadmill graded exercise test in competitive ice hockey players.

    Science.gov (United States)

    Fitzgerald, John S; Peterson, Ben J; Warpeha, Joseph M; Wilson, Patrick B; Rhodes, Greg S; Ingraham, Stacy J

    2014-11-01

    Vitamin D status has been associated with cardiorespiratory fitness (CRF) in cross-sectional investigations in the general population. Data characterizing the association between 25-hydroxyvitamin D (25(OH)D) concentration and CRF in athletes are lacking. Junior and collegiate ice hockey players were recruited from the Minneapolis, MN (44.9° N), area during the off-season period (May 16-June 28). The purpose of this study was to examine the cross-sectional association between 25(OH)D concentration and CRF in a sample population of competitive ice hockey players. Circulating 25(OH)D level was assessed from a capillary blood sample analyzed using liquid chromatography-tandem mass spectrometry. V[Combining Dot Above]O2peak during a skate treadmill graded exercise test (GXT) was used to assess CRF. Data on both 25(OH)D concentration and V[Combining Dot Above]O2peak were available for 52 athletes. Insufficient 25(OH)D concentrations were found in 37.7% of the athletes (skate treadmill GXT.

  5. Methodical basis of the preparing technology of the specialists in the competitive system activity in fgure skating on ice

    Directory of Open Access Journals (Sweden)

    Medvedeva I.M

    2010-10-01

    Full Text Available Methodology of competition activity of skilled fgure skaters is reasonable. The model of the special preparedness of future teachers is worked out. Maintenance and principles of process of teaching of students is worked out. Methodical bases of technology of teaching students to the construction of competition compositions are reasonable. The pedagogical departmental of students teaching is presented taking into account modern features and progress of fgure-skating trends on skates. Conception is based on a capture students professional knowledge, abilities and skills.

  6. The effect of sequence of skating-specific training on skating performance.

    Science.gov (United States)

    Farlinger, Chris Mj; Fowles, Jonathon R

    2008-06-01

    To determine the effectiveness of a progressively "skating specific" periodized off-season training program on skating performance in competitive hockey players. Twenty (M = 18; F = 2) highly skilled hockey players (age 15.9 +/- 1.5 yr) completed 16 wk of standardized resistance and stability training supplemented with either off-ice simulated skating using the SkateSIM (SIM) or plyometric training (PLY) in a crossover design. Group 1 (PLY-SIM; N = 11) completed 8 wk of PLY followed by 8 wk of SIM. Group 2 (SIM-PLY; N = 9) completed 8 wk of SIM followed by 8 wk of PLY. Subjects completed on- and off-ice testing PRE, MID, and POST training. Significant improvements in on-ice 35-m skating sprint (1.0%; P = .009) with significant improvements of 5% to 12% in various off-ice testing measures were observed PRE-MID in both groups. While few off-ice tests improved MID-POST, on-ice 35-m skating sprint times improved MID-POST by 2.3% (P = .000) with greater improvement in PLYSIM (3.5%) versus SIM-PLY (0.8%; P skating sprint performance. The initial gains PRE-MID and then the lack of improvement in many off-ice tests from the MID-POST supports the principle of diminishing returns in response to standardized resistance training. The improvement in on-ice skating sprint performance when supplemental training progressed in specificity supports the principle of specificity and promotes transfer to a complex sporting movement such as skating.

  7. Epidemiology of Figure Skating Injuries: A Review of the Literature.

    Science.gov (United States)

    Han, Julie S; Geminiani, Ellen T; Micheli, Lyle J

    2018-05-01

    As the popularity and technical demands of figure skating increase, so will the number of athletes presenting with sport-related problems. Searches were performed across PubMed from 1980 to 2017. The keywords searched were skating, skaters, incidence, and injuries. The search was limited to English-language articles and human participants. Relevant articles were cross-referenced. Clinical review. Level 5. Previous studies suggest an increase in incidence of figure skating injuries from 1982 to 2003. When combining all disciplines of figure skating, there is a similar proportion of acute and overuse injuries. Within disciplines, overuse injuries appear to be more common in singles skating, while acute injuries are more common in pairs skating, ice dancing, and synchronized skating. Lower extremity injuries are more common than upper extremity injuries in all disciplines, and pairs skating accounts for the majority of upper extremity injuries. Ankle sprains are the most common skating injury, and patellar tendinitis is the most common overuse injury across all disciplines. Stress fractures are the most common overuse injury in female singles skaters. The predominance of overuse injuries in singles disciplines reflects their increasing technical difficulty, with more difficult jumps and longer training hours. Partner disciplines are more likely to involve acute injuries and upper extremity injuries due to high-risk throws and lifts. Emphasis should be placed on properly fitting skating boots, intrinsic foot and ankle strengthening, and lower extremity flexibility, which may prevent many of the common lower extremity and back injuries in figure skating.

  8. Longevity of men capable of prolonged vigorous physical exercise: a 32 year follow up of 2259 participants in the Dutch eleven cities ice skating tour.

    Science.gov (United States)

    van Saase, J L; Noteboom, W M; Vandenbroucke, J P

    1990-01-01

    OBJECTIVE--To compare the long term survival of a group of athletes taking prolonged vigorous physical exercise to that of the general population. DESIGN--Follow up of a cohort of participants in the Dutch eleven cities ice skating tour (a race and recreational tour) over a distance of 200 kilometers. SETTING--Data on participation from the organising committee and data on mortality from all municipalities in The Netherlands. SUBJECTS--2259 Male athletes. MAIN OUTCOME MEASURES--Comparison of all cause mortality in male participants in the tour with that in the general population of The Netherlands. RESULTS--The standardised mortality ratio for all participants during 32 years of follow up was 0.76 (95% confidence interval 0.68 to 0.85), and 0.90 (0.48 to 1.44) for participants in the race, and 0.72 (0.60 to 0.86) for participants in the recreational tour who finished within the time limit. CONCLUSIONS--The capacity for prolonged and vigorous physical exercise, particularly if the exercise is recreational, is a strong indicator of longevity. Images p1409-a p1411-a PMID:2279154

  9. IN SEARCH OF GOOD PERFORMANCE INDICATORS FOR SPEED SKATING

    NARCIS (Netherlands)

    van der Eb, J.W.; Zandee, Willem; van der Bogaard, Timo; Veeger, H.E.J.; Beek, P.J.

    The force produced to propel a body forward in speed skating is directed almost perpendicular to the forward motion, because a skate moves nearly frictionless in the for-aft direction and more or less fixed (against the ice) in sideways lateral direction, resulting in a sliding point to push off

  10. IN SEARCH OF GOOD PERFORMANCE INDICATORS FOR SPEED SKATING

    NARCIS (Netherlands)

    van der Eb, J.W.; Zandee, Willem; van der Bogaard, Timo; Veeger, H.E.J.; Beek, Peter

    2017-01-01

    The force produced to propel a body forward in speed skating is directed almost perpendicular to the forward motion, because a skate moves nearly frictionless in the for-aft direction and more or less fixed (against the ice) in sideways lateral direction, resulting in a sliding point to push off

  11. Hip adductor muscle function in forward skating.

    Science.gov (United States)

    Chang, Ryan; Turcotte, Rene; Pearsall, David

    2009-09-01

    Adductor strain injuries are prevalent in ice hockey. It has long been speculated that adductor muscular strains may be caused by repeated eccentric contractions which decelerate the leg during a stride. The purpose of this study was to investigate the relationship of skating speed with muscle activity and lower limb kinematics, with a particular focus on the role of the hip adductors. Seven collegiate ice hockey players consented to participate. Surface electromyography (EMG) and kinematics of the lower extremities were measured at three skating velocities 3.33 m/s (slow), 5.00 m/s (medium) and 6.66 m/s (fast). The adductor magnus muscle exhibited disproportionately larger increases in peak muscle activation and significantly prolonged activation with increased speed. Stride rate and stride length also increased significantly with skating velocity, in contrast, hip, knee and ankle total ranges of motion did not. To accommodate for the increased stride rate with higher skating speeds, the rate of hip abduction increased significantly in concert with activations of adductor magnus indicating a substantial eccentric contraction. In conclusion, these findings highlight the functional importance of the adductor muscle group and hip abduction-adduction in skating performance as well as indirectly support the notion that groin strain injury potential increases with skating speed.

  12. Roller skating--is it a dangerous sport?

    Science.gov (United States)

    Tse, P Y; Shen, W Y; Chan, K M; Leung, P C

    1987-01-01

    A prospective survey of 111 cases of roller skating injuries within one year are reported. Males were more commonly injured than females. There was a high incidence (86%) of serious injuries, 28% of which required surgical treatment. The wrist (23%) was the commonest region involved, followed by the shoulder (20%), the elbow (15%) and the ankle (12%). Collision with other skaters and loss of control were the main factors leading to injury. Better rink discipline, instruction classes and safety publicity should be helpful in minimising accidents. Images Fig. 2 & Fig. 3 PMID:3676638

  13. Design and engineering of a gas-engine driven heat pump heating station including heat distribution system and utilization of waste heat from an ice rink for the residential area Dorsten - Maria Lindenhof. Planung eines Gasmotor-Waermepumpenheizwerkes mit angeschlossenem Waermeverteilungsnetz und Abwaermenutzung einer Eisenbahn fuer das zentralstaedtische Gebiet 'Maria-Lindenhof' in Dorsten

    Energy Technology Data Exchange (ETDEWEB)

    Huelsemann, R.

    1984-05-01

    A gas-engine driven heat pump heating station including the required heat destribution system and utilization of waste heat from an ice rink to be realized in the residential area Dorsten - Maria Lindenhof. The total heat capacity was to be reached in two stages, corresponding to the progress of the building and housing structure in this specific area: First stage of construction 5,6 MW, final stage of construction 7,6 MW. With regard to the final stage of construction only a relatively small part of the buildings is provided with heating systems designed for supply and return temperatures of 90/70/sup 0/C respectively. The old people's home built in 1980 was already equipped with low temperature heating systems and all buildings still to be built shall be provided with low-temperature systems. As far as old heating systems are concerned, the required measures must be taken to reduce the temperature in the return lines.

  14. Energy efficiency in arenas : the effect of the distribution circuit on the surface ice temperature; L'efficacite energetique dans les arenas : effet du circuit de distribution sur la temperature de surface de la glace

    Energy Technology Data Exchange (ETDEWEB)

    Bellache, O.; Cummins, R.; Lavallee, H. [Systeme Energie TST, Laval, PQ (Canada)

    2009-03-15

    The ice in most arenas is cooled by brine chillers which consume large amounts of energy. The pump alone that circulates the brine in the piping system underneath the cement consumes as much as 15 per cent of the energy required to cool the ice. This article described a new brine system for skating rinks that has been used in 20 arenas in Montreal. The brine specifications in the arenas were first updated. Then, the commonly used two-pass brine distribution systems with evaporators connected in parallel were replaced with a four-pass brine distribution system with evaporators connected in series. Brine flow was reduced by half and pump horsepower was also significantly reduced while maintaining sufficient fluid velocity in the heat exchangers. Money was also saved because less salt was needed to top up the system. The new design for the brine system is recommended for replacing corroded headers, because payback can be immediate. The new system maintains optimal ice conditions. While the ice quality remains the same, the money saved is substantial, notably 8,500 per rink per year. 3 refs., 9 figs.

  15. Instructor's guide : - synchronized skating school

    OpenAIRE

    Mokkila, Eveliina

    2011-01-01

    The starting point to the Instructor’s guide for synchronized skating school was the situation that Turun Riennon Taitoluistelu figure skating club constantly struggles to get enough skaters to the Beginner team in synchronized skating. The guidebook was written to guide the skating school instructors towards providing more synchronized skating teaching in their lessons. As a result from introducing synchronized skating more in the skating school, it is expected to have more children conti...

  16. Getting the Angles Straight in Speed Skating : A Validation Study on an IMU Filter Design to Measure the Lean Angle of the Skate on the Straights

    NARCIS (Netherlands)

    Van Der Kruk, E.; Schwab, A. L.; Van Der Helm, F. C.T.; Veeger, H. E.J.

    2016-01-01

    To assist speed skaters in improving their skating performance, we would like to provide them with real time feedback on the orientation of the skate within a single stroke. While of course the forces generated by the skater on the ice determine the acceleration of the skater, the orientation of the

  17. Getting the angles straight in speed skating : A validation study on an IMU filter design to measure the lean angle of the skate on the straights

    NARCIS (Netherlands)

    van der Kruk, E.; Schwab, A.L.; van der Helm, F.C.T.; Veeger, H.E.J.; van der Helm, FCT; Jansen, AJ

    2016-01-01

    To assist speed skaters in improving their skating performance, we would like to provide them with real time feedback on the orientation of the skate within a single stroke. While of course the forces generated by the skater on the ice determine the acceleration of the skater, the orientation of

  18. A comparison of VO2max and metabolic variables between treadmill running and treadmill skating.

    Science.gov (United States)

    Koepp, Kriston K; Janot, Jeffrey M

    2008-03-01

    The purpose of this study was to determine differences in VO2max and metabolic variables between treadmill running and treadmill skating. This study also examined VO2max responses during a continuous skating treadmill protocol and a discontinuous skating treadmill protocol. Sixteen male high school hockey players, who had a mean age of 16 +/- 1 years and were of an above-average fitness level, participated in this study. All subjects completed 4 exercise trials: a 1-hour skating treadmill familiarization trial, a treadmill running trial, and 2 randomized skating treadmill trials. Minute ventilation (VE), oxygen consumption VO2), carbon dioxide production VCO2), respiratory exchange ratio (RER), and heart rate were averaged every 15 seconds up to VO2max for each exercise test. The results showed that there was a significant difference (P skating treadmill protocol. There was also a significant difference for maximal RER between the discontinuous and continuous skating treadmill protocol and between the discontinuous skating treadmill protocol and running treadmill protocol. In conclusion, the running treadmill elicited a greater VO2max (mL.kg.min) than the skating treadmill did, but when it comes to specificity of ice skating, the skating treadmill may be ideal. Also, there was no significant difference between the discontinuous and continuous skating treadmill protocols. Therefore, a continuous protocol is possible on the skating treadmill without compromising correct skating position and physiologic responses. However, the continuous skating treadmill protocol should undergo validation before other scientists, coaches, and strength and conditioning professionals can apply it correctly.

  19. Turg Tallinnas = A market for Tallinn / Max Rink

    Index Scriptorium Estoniae

    Rink, Max

    2007-01-01

    Hollandi arhitektuurikoolide lõputööde preemia Archiprix võitis 2007. a. Max Rink Delfti Tehnikaülikoolist Tallinna Balti jaama turu asemele kavandatud mitmefunktsioonilise turuhoone projektiga "Maja-turg". Juhendaja Klaske Havik

  20. Endurance in speed skating

    NARCIS (Netherlands)

    Kuper, Gerard H.; Sterken, Elmer

    2001-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

  1. Nonparticipant injuries associated with skating activities.

    Science.gov (United States)

    Knox, Christy L; Comstock, R Dawn

    2006-03-01

    Children are at risk for injury even if they are not active recreational participants. This study describes the epidemiology of pediatric nonparticipant skating-related injuries treated in hospital emergency departments in the United States from 1993 to 2003. Narratives of injuries identified by the US Consumer Product Safety Commission's National Electronic Injury Surveillance System consumer product codes as ice-skating, roller-skating, and in-line skating-related were reviewed. Fifty-eight children were treated for nonparticipant skating-related injuries in National Electronic Injury Surveillance System emergency departments. Mechanisms of injury included being stepped on (36.2%), dropped (34.5%), or kicked (12.1%) by skaters and collision with skaters (17.2%). The most common body regions injured were the lower extremities (41.4%), upper extremities (24.1%), and head (20.7%). Contusions/abrasions (32.8%), lacerations (20.7%), and fractures (19.0%) were the most common diagnoses. Children who were dropped sustained more head injuries than children injured by other mechanisms (relative risk [RR], 20.9; 95% confidence interval [CI], 2.9-150.5; P < 0.001) and were younger than those stepped on (RR, 1.5; 95% CI, 1.1-2.2; P = 0.02) or kicked (RR, 6.7; 95% CI, 1.1-40.9; P < 0.001). Children stepped on by skaters experienced more injuries to the extremities than children who were dropped by (RR, 3.3; 95% CI, 1.7-6.5; P < 0.001) or collided with skaters (RR, 1.7; 95% CI, 1.0-2.8; P < 0.01). Children are at risk for injury when they are around skaters. The risk of such injuries can be reduced if children are never carried by skaters, young children are closely supervised to avoid collisions, and skaters are cautioned against kicking or stepping on other children.

  2. Push-off mechanics in speed skating with conventional skates and klapskates.

    Science.gov (United States)

    Houdijk, H; de Koning, J J; de Groot, G; Bobbert, M F; And; van Ingen Schenau, G J

    2000-03-01

    Personal and world records in speed skating improved tremendously after the introduction of the klapskate, which allows the foot to plantar flex at the end of the push-off while the full blade continues to glide on the ice. The purpose of this study was to gain insight into the differences in skating technique with conventional versus klapskates and to unveil the source of power enhancement using klapskates. Ten elite speed skaters skated four 400-m laps at maximal effort with both conventional and klapskates. On the straight high-speed film, push-off force and EMG data were collected. An inverse dynamics analysis was performed in the moving reference plane through hip, knee, and ankle. Skating velocity increased 5% as a result of an increase in mean power output of 25 W when klapskates were used instead of conventional skates. The increase in mean power output was achieved through an 11-J increase in work per stroke and an increase in stroke frequency from 1.30 to 1.36 strokes x s(-1). The difference in work per stroke occurs during the final 50 ms of the push-off. This is the result of the ineffective way in which push-off forces are generated with conventional skates when the foot rotates about the long front end of the blade. No differences in muscle coordination were observed from EMG. A hinge under the ball of the foot enhances the effectiveness of plantar flexion during the final 50 ms of the push off with klapskates and increases work per stroke and mean power output.

  3. Analysis of High-Intensity Skating in Top-Class Ice Hockey Match-Play in Relation to Training Status and Muscle Damage

    DEFF Research Database (Denmark)

    Lignell, Erik; Fransson, Dan; Krustrup, Peter

    2018-01-01

    of training status. Male ice-hockey players (n = 36) from the National Hockey League participated. Match analysis was performed during a game and physical capacity was assessed by a submaximal Yo-Yo Intermittent Recovery Ice-hockey test, level 1 (YYIR1-IHSUB). Venous blood samples were collected 24-hour post...

  4. Medical issues in synchronized skating.

    Science.gov (United States)

    Abbott, Kristin; Hecht, Suzanne

    2013-01-01

    Synchronized skating is a unique sport of team skating and currently represents the largest competitive discipline in U.S. Figure Skating. Synchronized skating allows skaters to compete as part of a team with opportunities to represent their country in international competitions. As the popularity of the sport continues to grow, more of these athletes will present to sports medicine clinics with injuries and illnesses related to participation in synchronized skating. The purpose of this article is to review the common injuries and medical conditions affecting synchronized skaters.

  5. Endurance in speed skating

    NARCIS (Netherlands)

    Kuper, G.H.; Sterken, E.

    2002-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for bothmen and women. The historical data show that it is likely that the relation betweenskating speed and distance of the various events is non-linear and converges to a limitvalue. We pay special attention to technical

  6. A therapeutic skating intervention for children with autism spectrum disorder.

    Science.gov (United States)

    Casey, Amanda Faith; Quenneville-Himbeault, Gabriel; Normore, Alexa; Davis, Hanna; Martell, Stephen G

    2015-01-01

    The purpose of this study was to evaluate the effects of a highly structured therapeutic skating intervention on motor outcomes and functional capacity in 2 boys with autism spectrum disorder aged 7 and 10 years. This multiple-baseline, single-subject study assigned participants to three 1-hour skating sessions per week for 12 weeks focusing on skill and motor development. Multiple data points assessed (a) fidelity to the intervention and (b) outcomes measures including the Pediatric Balance Scale, Timed Up and Go, floor to stand, Six-Minute Walk Test, goal attainment, and weekly on-ice testing. Improvements were found in balance, motor behavior, and functional capacity by posttest with gains remaining above pretest levels at follow-up. Therapeutic skating may produce physical benefits for children with autism spectrum disorder and offer a viable, inexpensive community-based alternative to other forms of physical activity.

  7. Dental injuries in inline skating - level of information and prevention.

    Science.gov (United States)

    Fasciglione, Daniele; Persic, Robert; Pohl, Yango; Filippi, Andreas

    2007-06-01

    Inline skating belongs like ice hockey, rugby, and boxing to sporting activities with high-risk of suffering tooth accidents. Because of high velocity and loss of balance, especially on uneven ground, the injury potential in inline skating is higher. The objective of this work was to conduct a comparative study between Switzerland and Germany. The questions focussed on the frequency of tooth accidents, their prevention by mouthguard and the level of information about emergency measures after dental trauma and the resulting consequences for athletes. Using a standardized questionnaire totally 612 individuals, 324 men and 288 women, in two countries belonging to three different divisions (fun, fitness and speed) were surveyed. Fifty-six (9.2%) of these 612 interviewees have already experienced a tooth injury while inline skating. More than half of all interviewed players (68.3%) were aware of the possibility of replanting avulsed teeth. Only 32.4% were familiar with the tooth rescue kit. Just 65.4% knew mouthguard and only 1.9% of those athletes (n = 12) wore a mouthguard while inline skating. The results show that the area of inline skating requires more information about preventing dental trauma through sports associations and dentists.

  8. Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

    Directory of Open Access Journals (Sweden)

    Pantoja Patrícia Dias

    2014-07-01

    Full Text Available This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions.

  9. Neuromuscular Responses of Elite Skaters During Different Roller Figure Skating Jumps

    Science.gov (United States)

    Pantoja, Patrícia Dias; Mello, André; Liedtke, Giane Veiga; Kanitz, Ana Carolina; Cadore, Eduardo Lusa; Pinto, Stephanie Santana; Alberton, Cristine Lima; Kruel, Luiz Fernando Martins

    2014-01-01

    This study aimed to describe the neuromuscular activity of elite athletes who performed various roller figure skating jumps, to determine whether the muscle activation is greater during jumps with more rotations and in which phase the muscles are more active. This study also aimed to analyze if there is any difference in the muscle activity pattern between female and male skaters. Four elite skaters were evaluated, and each participated in two experimental sessions. During the first session, anthropometric data were collected, and the consent forms were signed. For the second session, neuromuscular data were collected during jumps, which were performed with skates at a rink. The following four roller figure skating jumps were evaluated: single Axel, double Axel, double Mapes and triple Mapes. The neuromuscular activity of the following seven muscles was obtained with an electromyograph which was fixed to the waist of each skater with a strap: biceps femoris, lateral gastrocnemius, tibialis anterior, rectus femoris, vastus lateralis, vastus medialis and gluteus maximus. The signal was transmitted wirelessly to a laptop. During the roller figure skating jumps, the lateral gastrocnemius, rectus femoris, vastus lateralis, biceps femoris and gluteus maximus, showed more activation during the jumps with more rotations, and the activation mainly occurred during the propulsion and flight phases. Female skaters demonstrated higher muscle activities in tibialis anterior, vastus lateralis, vastus medialis and gluteus maximus during the landing phase of the triple Mapes, when compared to their male counterparts. The results obtained in this study should be considered when planning training programs with specific exercises that closely resemble the roller figure skating jumps. This may be important for the success of elite skaters in competitions. PMID:25114728

  10. 75 FR 53261 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Reduction of Skate...

    Science.gov (United States)

    2010-08-31

    ...NMFS announces the reduction of the skate wing fishery possession limit for the Skate Management Unit for the remainder of the 2010 fishing year. Regulations governing the skate fishery require publication of this notification to advise skate-permitted vessels that 80 percent of the annual total allowable landings (TAL) of skate wings is projected to be harvested and to announce that the skate wing possession limit is reduced.

  11. High and dry skating in Inzell, Austria; Hoog en nu ook droog schaatsen in Inzell

    Energy Technology Data Exchange (ETDEWEB)

    Berends, E. [GEA Grenco Refrigeration, Den Bosch (Netherlands)

    2011-03-15

    In March 2010 work started on a roof to cover the ice rink in Inzell, Austria. This article provides a brief overview of the design (roof Construction), the air conditioning and the freezer installation. [Dutch] In maart 2010 is begonnen met de overkapping van de ijsbaan in Inzell, Oostenrijk. In dit artikel wordt kort een overzicht gegeven van het ontwerp (dakconstructie), de luchtbehandeling en de vriesinstallatie.

  12. Relationship between strength qualities and short track speed skating performance in young athletes.

    Science.gov (United States)

    Felser, S; Behrens, M; Fischer, S; Heise, S; Bäumler, M; Salomon, R; Bruhn, S

    2016-02-01

    This study analyzed the relationships between isometric as well as concentric maximum voluntary contraction (MVC) strength of the leg muscles and the times as well as speeds over different distances in 17 young short track speed skaters. Isometric as well as concentric single-joint MVC strength and multi-joint MVC strength in a stable (without skates) and unstable (with skates) condition were tested. Furthermore, time during maximum skating performances on ice was measured. Results indicate that maximum torques during eversion and dorsal flexion have a significant influence on skating speed. Concentric MVC strength of the knee extensors was higher correlated with times as well as speeds over the different distances than isometric MVC strength. Multi-joint MVC testing revealed that the force loss between measurements without and with skates amounts to 25%, while biceps femoris and soleus showed decreased muscle activity and peroneus longus, tibialis anterior, as well as rectus femoris exhibited increased muscle activity. The results of this study depict evidence that the skating times and speeds are primarily influenced by concentric MVC strength of the leg extensors. To be able to transfer the strength onto ice in an optimal way, it is necessary to stabilize the knee and ankle joints. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. The evaluation of speed skating helmet performance through peak linear and rotational accelerations.

    Science.gov (United States)

    Karton, Clara; Rousseau, Philippe; Vassilyadi, Michael; Hoshizaki, Thomas Blaine

    2014-01-01

    Like many sports involving high speeds and body contact, head injuries are a concern for short track speed skating athletes and coaches. While the mandatory use of helmets has managed to nearly eliminate catastrophic head injuries such as skull fractures and cerebral haemorrhages, they may not be as effective at reducing the risk of a concussion. The purpose of this study was to evaluate the performance characteristics of speed skating helmets with respect to managing peak linear and peak rotational acceleration, and to compare their performance against other types of helmets commonly worn within the speed skating sport. Commercially available speed skating, bicycle and ice hockey helmets were evaluated using a three-impact condition test protocol at an impact velocity of 4 m/s. Two speed skating helmet models yielded mean peak linear accelerations at a low-estimated probability range for sustaining a concussion for all three impact conditions. Conversely, the resulting mean peak rotational acceleration values were all found close to the high end of a probability range for sustaining a concussion. A similar tendency was observed for the bicycle and ice hockey helmets under the same impact conditions. Speed skating helmets may not be as effective at managing rotational acceleration and therefore may not successfully protect the user against risks associated with concussion injuries.

  14. Development and Validation of a Method for Determining Tridimensional Angular Displacements with Special Applications to Ice Hockey Motions.

    Science.gov (United States)

    Gagnon, Micheline; And Others

    1983-01-01

    A method for determining the tridimensional angular displacement of skates during the two-legged stop in ice hockey was developed and validated. The angles were measured by geometry, using a cinecamera and specially equipped skates. The method provides a new tool for kinetic analyses of skating movements. (Authors/PP)

  15. Welding skate with computerized controls

    Science.gov (United States)

    Wall, W. A., Jr.

    1968-01-01

    New welding skate concept for automatic TIG welding of contoured or double-contoured parts combines lightweight welding apparatus with electrical circuitry which computes the desired torch angle and positions a torch and cold-wire guide angle manipulator.

  16. Historical Improvement in Speed Skating Economy

    NARCIS (Netherlands)

    Noordhof, Dionne A; Tok, Elmy van; Joosten, Florentine S J G M; Hettinga, Florentina J; Hoozemans, Marco J M; Foster Jr., Carl; Koning, Jos J de

    Half the improvement in 1500-m speed-skating world records can be explained by technological innovations and the other half by athletic improvement. It is hypothesized that improved skating economy is accountable for much of the athletic improvement. PURPOSE: To determine skating economy in

  17. Experimental evaluation of the power balance model of speed skating.

    Science.gov (United States)

    de Koning, Jos J; Foster, Carl; Lampen, Joanne; Hettinga, Floor; Bobbert, Maarten F

    2005-01-01

    Prediction of speed skating performance with a power balance model requires assumptions about the kinetics of energy production, skating efficiency, and skating technique. The purpose of this study was to evaluate these parameters during competitive imitations for the purpose of improving model predictions. Elite speed skaters (n = 8) performed races and submaximal efficiency tests. External power output (P(o)) was calculated from movement analysis and aerodynamic models and ice friction measurements. Aerobic kinetics was calculated from breath-by-breath oxygen uptake (Vo(2)). Aerobic power (P(aer)) was calculated from measured skating efficiency. Anaerobic power (P(an)) kinetics was determined by subtracting P(aer) from P(o). We found gross skating efficiency to be 15.8% (1.8%). In the 1,500-m event, the kinetics of P(an) was characterized by a first-order system as P(an) = 88 + 556e(-0.0494t) (in W, where t is time). The rate constant for the increase in P(aer) was -0.153 s(-1), the time delay was 8.7 s, and the peak P(aer) was 234 W; P(aer) was equal to 234[1 - e(-0.153(t-8.7))] (in W). Skating position changed with preextension knee angle increasing and trunk angle decreasing throughout the event. We concluded the pattern of P(aer) to be quite similar to that reported during other competitive imitations, with the exception that the increase in P(aer) was more rapid. The pattern of P(an) does not appear to fit an "all-out" pattern, with near zero values during the last portion of the event, as assumed in our previous model (De Koning JJ, de Groot G, and van Ingen Schenau GJ. J Biomech 25: 573-580, 1992). Skating position changed in ways different from those assumed in our previous model. In addition to allowing improved predictions, the results demonstrate the importance of observations in unique subjects to the process of model construction.

  18. Commercialization of an electric propulsion unit for ecological ice resurfacers

    Energy Technology Data Exchange (ETDEWEB)

    Giroux, M. [MG Service, L' Assomption, PQ (Canada); Sylvestre, P. [Environment Canada, Montreal, PQ (Canada)

    2000-03-01

    Community health departments (CHD) and the general public are greatly concerned about the air quality at indoor skating rinks. A solution now exists whereby municipalities can convert their internal combustion resurfacers to electricity, using a system proposed by MG Service. This electric propulsion unit was developed and designed by MG Service, in conjunction with the Centre d'experimentation des vehicules electriques du Quebec (CEVEQ) and TPR Inc., an engineering firm. The main advantage of this technology is the ease of integration into the chassis of conventional resurfacers currently in use throughout the various municipalities. The propulsion unit is battery-powered and designed to replace the internal combustion engine. As a result, it eliminates carbon monoxide and nitrogen dioxide emissions, and more than meets the requirements set by health boards with regard to air quality at indoor skating rinks. Recyclable, maintenance-free and manufactured according to the standards set by the Underwriters Laboratories of Canada (ULC), the gel-sealed batteries display great advantages. The cost effectiveness of the electric propulsion unit is more impressive when considering that electricity is clean and costs five times less than conventional fuels currently in use. Regular verifications and calibrations are not required and the maintenance is minimal. The ventilation requirements are also reduced, leading to savings in energy costs required for the aeration of the indoor skating rink. Finally, the elimination of tank rental and fuel costs represent an added benefit. A detailed description of the components is provided. Following a series of trials, the operators were impressed by the surface gripability, traction and manoeuvrability. The resurfacers also gave an impression of greater raw power and were very quiet and easy to use, resulting in better overall operation when compared to conventional resurfacers. 1 fig.

  19. [Injury pattern caused by aggressive inline skating].

    Science.gov (United States)

    Hilgert, R E; Besch, L; Behnke, B; Egbers, H-J

    2004-12-01

    In order to evaluate the special injury pattern of aggressive inline skating, a field study was conducted in a local, non-commercial skate park equipped with all the typical features like ramps, halfpipes, gully areas. 66 unselected aggressive inline skaters were randomly enrolled and interviewed concerning their skating habits and their skating injury history. Average age was 15 (10 to 41) years, skating was performed since 2.1 (0.1 to 6) years, as aggressive skating since 1.3 (0.1 to 4) years. Medical treatment in a doctor's practice or in a hospital had been necessary in 66 cases, averaging 1.4 times per skater and year, averaging one injury per 586 hours of aggressive skating. The injury pattern reflected the regions typically injured in fitness skating, too, with a higher percentage of injuries concerning knee, tibia and ankle region. The use of protective devices varied from 41 % (wrist guards) to 94 % (knee pads), with an average of 69 %. Only 32 % of skaters wore all protective devices. As the personal thrill is an important motivation for aggressive skating, safer skating campaigns are quite unlikely to decrease the risk of injury in aggressive skaters.

  20. Historical Improvement in Speed Skating Economy.

    Science.gov (United States)

    Noordhof, Dionne A; van Tok, Elmy; Joosten, Florentine S J G M; Hettinga, Florentina J; Hoozemans, Marco J M; Foster, Carl; de Koning, Jos J

    2017-02-01

    Half the improvement in 1500-m speed-skating world records can be explained by technological innovations and the other half by athletic improvement. It is hypothesized that improved skating economy is accountable for much of the athletic improvement. To determine skating economy in contemporary athletes and to evaluate the change in economy over the years. Contemporary skaters of the Dutch national junior team (n = 8) skated 3 bouts of 6 laps at submaximal velocity, from which skating economy was calculated (in mL O 2 ・ kg -1 ・ km -1 ). A literature search provided historic data on skating velocity and submaximal V̇O 2 (in mL ・ kg -1 ・ min -1 ), from which skating economy was determined. The association between year and skating economy was determined using linear-regression analysis. Correcting the change in economy for technological innovations resulted in an estimate of the association between year and economy due to athletic improvement. A mean (± SD) skating economy of 73.4 ± 6.4 mL O 2 ・ kg -1 ・ km -1 was found in contemporary athletes. Skating economy improved significantly over the historical time frame (-0.57 mL O 2 ・ kg -1 ・ km -1 ・ y -1 , 95% confidence interval [-0.84, -0.31]). In the final regression model for the klapskate era, with altitude as confounder, skating economy improved with a nonsignificant -0.58 mL O 2 ・ kg -1 ・ km -1 ・ y -1 ([-1.19, 0.035]). Skating economy was 73.4 ± 6.4 mL O 2 ・ kg -1 ・ km -1 in contemporary athletes and improved over the past ~50 y. The association between year and skating economy due to athletic improvement, for the klapskate era, approached significance, suggesting a possible improvement in economy over these years.

  1. Choreography Styles in Figure Skating

    Science.gov (United States)

    Moormann, Peter Paul

    2006-01-01

    Fifty-eight figure skating trainers from fifteen different countries acted as volunteers in this study on choreography styles. The styles were based on reports of artistic-creative strategies in composing music, drawing, writing poems or novels, and in making dances. The prevalence of the Mozartian (at the onset the choreographer already has a…

  2. Nanofriction: Skating on hot surfaces

    Science.gov (United States)

    Meyer, Ernst; Gnecco, Enrico

    2007-03-01

    Simulations of nanoscale sharp tips sliding on a salt surface predict vanishing friction at temperatures close to the melting temperature, as the tip skates on a layer of liquefied salt. This insight opens the way to applications in MEMS, NEMS and auto/aerospace engines.

  3. Robust multiple cue fusion-based high-speed and nonrigid object tracking algorithm for short track speed skating

    Science.gov (United States)

    Liu, Chenguang; Cheng, Heng-Da; Zhang, Yingtao; Wang, Yuxuan; Xian, Min

    2016-01-01

    This paper presents a methodology for tracking multiple skaters in short track speed skating competitions. Nonrigid skaters move at high speed with severe occlusions happening frequently among them. The camera is panned quickly in order to capture the skaters in a large and dynamic scene. To automatically track the skaters and precisely output their trajectories becomes a challenging task in object tracking. We employ the global rink information to compensate camera motion and obtain the global spatial information of skaters, utilize random forest to fuse multiple cues and predict the blob of each skater, and finally apply a silhouette- and edge-based template-matching and blob-evolving method to labelling pixels to a skater. The effectiveness and robustness of the proposed method are verified through thorough experiments.

  4. [Injury patterns and prophylaxis in inline skating].

    Science.gov (United States)

    Jerosch, J; Heck, C

    2005-05-01

    Inline skating has become one of the fastest growing sports since its appearance in 1980. The increasing number of inline skaters has also led to a rising incidence of injuries. The most common injury is the distal fracture of the radius, which occurs in 50% of all fractures. There are several reasons for increasing serious injuries in inline skating. The majority of skaters do not wear proper protective equipment (helmet, elbow, knee and wrist protectors), however, many users can not handle their inline skates in dangerous situations. All skaters should take care by buying industrially tested inline skates and appropriate protective equipment; novice skaters should additionally attend special skating schools to learn skating, braking and the the correct falling techniques.

  5. The 1982 epidemic--roller skating injuries.

    Science.gov (United States)

    Bunker, T. D.

    1983-01-01

    A series of 100 roller skating injuries is presented. Roller skating injuries have been occurring at a higher rate than the previously reported skateboarding epidemic of 1977. The severity of injury has been lower, 32% fractures and dislocations occurring whilst roller skating, compared to 60% whilst skateboarding. In particular a striking reduction is seen in ankle fractures. Fifty questionnaires detailing method of injury were analysed. Images p205-a Fig. 1 Fig. 2 PMID:6652406

  6. Skate na cidade, imagens da cidade

    OpenAIRE

    Machado, Giancarlo Marques Carraro

    2014-01-01

    Apesar da existência de dezenas de pistas de skate na cidade de São Paulo – espaços considerados “próprios” para o skate -, a maioria dos skatistas da modalidade street skate confere maior importância à prática feita nas ruas, onde, para muitos, se “anda de skate de verdade”. A atração que elas exercem é a possibilidade de encontrar diferentes tipos de picos, ou seja, equipamentos urbanos (bancos, corrimãos, escadas, canteiros) obstáculos onde se realizam as manobras. Este artigo busca analis...

  7. [Intellectual exchange between Germany and Latin America: an interview with Stefan Rinke].

    Science.gov (United States)

    Rinke, Stefan; da Silva, André Felipe Cândido; Junghans, Miriam; Cavalcanti, Juliana Manzoni; de Muñoz, Pedro Felipe Neves

    2014-01-01

    Current and former students of the Casa de Oswaldo Cruz/Fiocruz interviewed German historian Stefan Rinke, of the Freie Universität Berlin, who specializes in examining the historical development of Latin America as it fits into the international context. Rinke's work uses dimensions such as economic and diplomatic relations, migratory flows, and ethnic conflict as tools in his analyses of the networks of interdependence that have tied Latin America to Europe and the USA. His lens goes beyond the Latin American continent to approach globalization as a historical process, with national and regional contexts placed within a general framework. In this interview, Rinke talks about his academic career, global and transnational history, and joint projects between Germany and Latin America.

  8. Tilintarkastusasiakkaan riskiluokittelu ja väärinkäytökset

    OpenAIRE

    Hieturi, Jonna

    2013-01-01

    Tilintarkastusasiakkaan riskiluokittelu on koko tilintarkastuksen ajan jatkuva prosessi. Riskiluokittelu alkaa toimeksiantosopimuksen solmimisesta ja päättyy tilintarkastuskertomuksen luovuttamiseen. Kyseisen luokittelun avulla yritetään vähentää riskiä mahdollisista väärinkäytöksistä. Erilaisia riskejä ovat väärinkäytösriskit, olennaisen virheellisyyden riskeihin lukeutuvat toiminta- ja kontrolliriski sekä merkittävät riskit. Yhdessä HTM-tilintarkastaja Jorma Nuutisen kanssa toteutimme haas...

  9. Race Factors Affecting Performance Times in Elite Long-Track Speed Skating.

    Science.gov (United States)

    Noordhof, Dionne A; Mulder, Roy C; de Koning, Jos J; Hopkins, Will G

    2016-05-01

    Analysis of sport performance can provide effects of environmental and other venue-specific factors in addition to estimates of within-athlete variability between competitions, which determines smallest worthwhile effects. To analyze elite long-track speed-skating events. Log-transformed performance times were analyzed with a mixed linear model that estimated percentage mean effects for altitude, barometric pressure, type of rink, and competition importance. In addition, coefficients of variation representing residual venue-related differences and within-athlete variability between races within clusters spanning ~8 d were determined. Effects and variability were assessed with magnitude-based inference. A 1000-m increase in altitude resulted in very large mean performance improvements of 2.8% in juniors and 2.1% in seniors. An increase in barometric pressure of 100 hPa resulted in a moderate reduction in performance of 1.1% for juniors but an unclear effect for seniors. Only juniors competed at open rinks, resulting in a very large reduction in performance of 3.4%. Juniors and seniors showed small performance improvements (0.4% and 0.3%) at the more important competitions. After accounting for these effects, residual venue-related variability was still moderate to large. The within-athlete within-cluster race-to-race variability was 0.3-1.3%, with a small difference in variability between male (0.8%) and female juniors (1.0%) and no difference between male and female seniors (both 0.6%). The variability in performance times of skaters is similar to that of athletes in other sports in which air or water resistance limits speed. A performance enhancement of 0.1-0.4% by top-10 athletes is necessary to increase medal-winning chances by 10%.

  10. Parameter analysis for speed skating performance

    NARCIS (Netherlands)

    van der Kruk, E.

    2018-01-01

    Speed skating is a rather special form of locomotion. While in most types of human locomotion, humans generate forces by pushing against the environment in the opposite direction of motion, in speed skating the skater pushes sideward to propel himself forward; Insight in the details of the technique

  11. Difference in Agility, Strength, and Flexibility in Competitive Figure Skaters Based on Level of Expertise and Skating Discipline.

    Science.gov (United States)

    Slater, Lindsay V; Vriner, Melissa; Zapalo, Peter; Arbour, Kat; Hart, Joseph M

    2016-12-01

    Slater, LV, Vriner, M, Zapalo, P, Arbour, K, and Hart, JM. Difference in agility, strength, and flexibility in competitive figure skaters based on level of expertise and skating discipline. J Strength Cond Res 30(12): 3321-3328, 2016-Figure skating is an extremely difficult sport that requires a combination of grace, artistry, flexibility, speed, and power. Although many skaters are involved with strength and conditioning programs, there is no current information about differences in off-ice performance measures based on skating discipline and level. The purpose of this study was to compare agility, strength, and flexibility performance based on skating discipline and level. A total of 343 figure skaters from 4 different disciplines (singles, dance, pair, and synchronized skating) and 3 different levels (novice, junior, and senior) completed combine testing with the United States Figure Skating Association. All subjects completed the hexagon agility test, t-test, triple bound jumps, vertical jump, timed tuck jumps, push-ups, v-ups, hand press, front split, seated reach, and stork pose. A multivariate analysis of variance with Scheffe's post hoc was used to identify differences in performance based on skating discipline and level. Mean differences, Cohen's d effect sizes, and 95% confidence intervals were reported for all significant differences. Senior and junior skaters tended to be faster and stronger than novice skaters. Singles, dance, and pair skaters tended to be more agile, stronger, and flexible than synchronized skaters, however, senior synchronized skaters tended to perform better than senior skaters in other disciplines. These results indicate that strength and conditioning professionals should consider skating discipline and level when designing strengthening programs for figure skaters.

  12. Nuevo centro olímpico en Lake Placid, EE.UU

    OpenAIRE

    Hellmuth, George; Obata, Gyo; Kassabaum, George

    1980-01-01

    This new sports center, site of the 1980 Winter Olympic Games, consists of a main ice rink of Olympic size with seating for 8000 spectators, in addition to a smaller rink used for the U.S. Games. The auxiliary services are found under the stands or in the structure which joins the new center to the rink used for the 1932 Games. The complex is completed with a Higher School and an oval rink for speed skating. With the combination of visible beams in white, seats in bright red...

  13. Design and verification of a simple 3D dynamic model of speed skating which mimics observed forces and motions.

    Science.gov (United States)

    van der Kruk, E; Veeger, H E J; van der Helm, F C T; Schwab, A L

    2017-11-07

    Advice about the optimal coordination pattern for an individual speed skater, could be addressed by simulation and optimization of a biomechanical speed skating model. But before getting to this optimization approach one needs a model that can reasonably match observed behaviour. Therefore, the objective of this study is to present a verified three dimensional inverse skater model with minimal complexity, which models the speed skating motion on the straights. The model simulates the upper body transverse translation of the skater together with the forces exerted by the skates on the ice. The input of the model is the changing distance between the upper body and the skate, referred to as the leg extension (Euclidean distance in 3D space). Verification shows that the model mimics the observed forces and motions well. The model is most accurate for the position and velocity estimation (respectively 1.2% and 2.9% maximum residuals) and least accurate for the force estimations (underestimation of 4.5-10%). The model can be used to further investigate variables in the skating motion. For this, the input of the model, the leg extension, can be optimized to obtain a maximal forward velocity of the upper body. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  14. Cardiovascular and vasoconstrictive actions of skate bradykinin in the little skate, Leucoraja erinacea (Elasmobranchii).

    Science.gov (United States)

    Dasiewicz, Patricia J; Conlon, J Michael; Anderson, W Gary

    2011-11-01

    The vasoconstrictive and cardiovascular actions of a recently identified bradykinin (BK)-related peptide (Gly-Ile-Thr-Ser-Trp-Leu-Pro-Phe) from the little skate, Leucoraja erinacea were examined in the unanesthetised little skate. Intra-arterial administration of a skate BK (0.1-1 nmolkg(-1)) produced a hypertensive response with a rise in blood pressure reaching a maximum elevation of 28.7±4.8% over baseline (Pskate BK. Further, in vivo administration of 1 nmolkg(-1) skate BK induced a significant delayed increase in stroke volume (reaching a maximum of 54.4±14.7% above baseline) without significant effect on either cardiac output or heart rate. In vitro, skate BK constricted the 1st branchial, mesenteric (EC(50) 2.7×10(-9)M) and coeliac (EC(50) 3.1×10(-9)M) arterial preparations of the skate. In contrast, skate [Arg(9)]BK, the mammalian B(1) receptor agonist des-[Arg(9)]BK, and the mammalian B(2) receptor antagonist HOE-140 failed to induce vasoconstriction in these isolated arterial preparations. The vasoconstrictor actions of skate BK in the isolated mesenteric, coeliac and branchial arterial preparations were significantly inhibited when co-administrated with esculetin and phentolamine. Indomethacin also inhibited the vasoconstrictor actions of skate BK in the isolated branchial artery. We conclude that, as in mammals and teleost fish, multiple pathways involving at least the alpha adrenergic and leukotriene synthesis pathway are involved in mediating the vasoconstrictive actions of BK in vascular smooth muscle of the little skate. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Changes in speed skating velocity in relation to push-off effectiveness.

    Science.gov (United States)

    Noordhof, Dionne A; Foster, Carl; Hoozemans, Marco J M; de Koning, Jos J

    2013-03-01

    Speed skating posture, or technique, is characterized by the push-off angle or effectiveness (e), determined as the angle between the push-off leg and the ice; the preextension knee angle (θ(0)); and the trunk angle (θ(1)). Together with muscle-power output and environmental conditions, skating posture, or technique, determines velocity (v). To gain insight into technical variables that are important to skate efficiently and perform well, e, θ(0), θ(1), and skating v were determined every lap during a 5000-m World Cup. Second, the authors evaluated if changes (Δ) in e, θ(0), and θ(1) are associated with Δv. One camera filmed the skaters from a frontal view, from which e was determined. Another camera filmed the skaters from a sagittal view, from which θ(0) and θ(1) were determined. Radio-frequency identification tags around the ankles of the skaters measured v. During the race, e progressively increased and v progressively decreased, while θ(0) and θ(1) showed a less consistent pattern of change. Generalized estimating equations showed that Δe is significantly associated with Δv over the midsection of the race (β = -0.10, P < .001) and that Δθ(0) and Δθ(1) are not significantly associated with Δv. The decrease in skating v over the race is not due to increases in power losses to air friction, as knee and trunk angle were not significantly associated with changes in velocity. The decrease in velocity can be partly ascribed to the decrease in effectiveness, which reflects a decrease in power production associated with fatigue.

  16. 36 CFR 1002.20 - Skating, skateboards and similar devices.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Skating, skateboards and similar devices. 1002.20 Section 1002.20 Parks, Forests, and Public Property PRESIDIO TRUST RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 1002.20 Skating, skateboards and similar devices. Using roller skates...

  17. The Protective Effect of Kevlar ® Socks Against Hockey Skate Blade Injuries: A Biomechanical Study

    Science.gov (United States)

    Nauth, Aaron; Aziz, Mina; Tsuji, Matthew; Whelan, Daniel B.; Theodoropoulos, John S.; Zdero, Rad

    2014-01-01

    simulate a typical ice hockey injury. Peak force, energy and power were calculated from the force-displacement data collected from the 7 matched pair trials. The cadavers were then dissected to identify the extent of the injury the skin and Achilles tendon from blade impact. Analysis of variance was used to test for a significant difference between the groups. Results: None (0/7) of the achilles tendons were lacerated when protected with Kevlar® reinforced socks; whereas all (7/7) achilles tendons tested using the standard synthetic sock were completely severed (Figure 1). Peak force (4030 +/- 1191 N vs. 2037 +/- 729 N), energy (81.4 +/- 38.9 J vs. 26.3 +/- 13.2 J) and power (471.2 +/- 166.7 W vs. 258.3 +/- 93.5 W) were all significantly (pKevlar® reinforced sock group compared to the standard synthetic sock group in our testing model (Figures 2 and 3). Conclusion: The Kevlar® reinforced socks provided significantly more cut resistance and were able to withstand a significantly larger peak force, energy and power from skate blade impact and prevent achilles tendon laceration when compared to standard synthetic hockey socks in a biomechanical testing model using human cadaver limbs. This is the first investigation to address the benefits of wearing Kevlar® reinforced hockey socks in a simulated model of hockey skate injuries and our results suggest a significant protective effect from the use of Kevlar® reinforced socks against hockey skate injuries.

  18. The association between changes in speed skating technique and changes in skating velocity

    NARCIS (Netherlands)

    Noordhof, D.A.; Foster Jr., C.C.; Hoozemans, M.J.M.; de Koning, J.J.

    2014-01-01

    A meaningful association between changes (Δ) in push-off angle or effectiveness (e) and changes in skating velocity (ν) has been found during 5000-m races, although no significant association was found between changes in knee (θ

  19. Observer-reported skate bycatch in the commercial groundfish fisheries of Alaska

    OpenAIRE

    Stevenson , Duane E.; Lewis , Kristy A.

    2010-01-01

    We analyzed skate catch data collected by observers in the North Pacific Groundfish Observer Program (NPGOP) from 1998 through 2008 to document recent changes in the identification of skates by observers and to examine the species composition of observed skate catch in Alaska’s groundfish fisheries as well as recent trends in skate retention by commercial fishermen. Historically, almost all skate bycatch has been reported by NPGOP observers as “skate unidentified.” However, since 2004 o...

  20. "Balancing on Skates on the Icy Surface of Work": a metasynthesis of work participation for persons with psychiatric disabilities.

    Science.gov (United States)

    Kinn, Liv Grethe; Holgersen, Helge; Aas, Randi W; Davidson, Larry

    2014-03-01

    To explore how persons with psychiatric disabilities experience facilitators of and barriers to participation in paid work in transitional, supported, and open employment settings, in order to provide guidance for efforts to attract and retain these persons in gainful employment as a key dimension of recovery and community life. A metasynthesis was conducted using 16 qualitative studies published between 1990 and 2011. Ten themes, two phases, and an overarching metaphor were identified. The first five themes describe facilitators of and impediments to getting a job (getting off the bench): (1) fighting inertia; (2) taking control; (3) encouraging peers; (4) disruptions related to the illness; (5) lack of opportunities and supports. The next five themes represent facilitators of and impediments to working (skating on the ice); (6) going mainstream; (7) social cohesion; (8) clarity in role and responsibilities; (9) environmental factors; (10) managing self-disclosure. We chose as our overarching metaphor "Balancing on Skates on the Icy Surface of Work," as we view both iceskaters and workers with psychiatric disabilities as needing to achieve and maintain their balance while being "on the edge" between various extremities. We have shown that, for persons with psychiatric disabilities to "get off the bench" and "onto the ice" of employment, they may need to be supported in finding and maintaining their balance in new situations through a combination of learning new skills and competencies (learning how to skate) while receiving in vivo assistance from empathic and knowledgeable supporters (being coached while on the ice).

  1. Stay Safe Riding Bikes or Skating Outside

    Centers for Disease Control (CDC) Podcasts

    2011-02-02

    In this podcast for kids, the Kidtastics talk about safety when outside, riding bikes or skating.  Created: 2/2/2011 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 2/2/2011.

  2. Variable-speed, portable routing skate

    Science.gov (United States)

    Pesch, W. A.

    1967-01-01

    Lightweight, portable, variable-speed routing skate is used on heavy metal subassemblies which are impractical to move to a stationary machine. The assembly, consisting of the housing with rollers, router, and driving mechanism with transmission, weighs about forty pounds. Both speed and depth of cut are adjustable.

  3. Roller Skating; Physical Education: 9.8414.

    Science.gov (United States)

    Amacker, Kathy; Mikell, Lenora

    GRADES OR AGES: Grades 7-12. SUBJECT MATTER: Methods and procedures of roller skating. ORGANIZATION AND PHYSICAL APPEARANCE: The contents are divided into six areas, which are Course Guidelines, Course Description and Accreditation Standard Broad Goal, Course of Study Behavioral Objectives, Course Content, Learning Activities and Teaching…

  4. Volumetric analysis of cerebellum in short-track speed skating players.

    Science.gov (United States)

    Park, In Sung; Lee, Nam Joon; Kim, Tae-Young; Park, Jin-Hoon; Won, Yu-Mi; Jung, Yong-Ju; Yoon, Jin-Hwan; Rhyu, Im Joo

    2012-12-01

    The cerebellum is associated with balance control and coordination, which might be important for gliding on smooth ice at high speeds. A number of case studies have shown that cerebellar damage induces impaired balance and coordination. As a positive model, therefore, we investigated whether plastic changes in the volumes of cerebellar subregions occur in short-track speed skating players who must have extraordinary abilities of balance and coordination, using three-dimensional magnetic resonance imaging volumetry. The manual tracing was performed and the volumes of cerebellar hemisphere and vermian lobules were compared between short-track speed skating players (n=16) and matched healthy controls (n=18). We found larger right cerebellar hemisphere volume and vermian lobules VI-VII (declive, folium, and tuber) in short-track speed skating players in comparison with the matched controls. The finding suggests that the specialized abilities of balance and coordination are associated with structural plasticity of the right hemisphere of cerebellum and vermian VI-VII and these regions play an essential role in balance and coordination.

  5. Improvement of Ice Hockey Players' On-Ice Sprint With Combined Plyometric and Strength Training.

    Science.gov (United States)

    Dæhlin, Torstein E; Haugen, Ole C; Haugerud, Simen; Hollan, Ivana; Raastad, Truls; Rønnestad, Bent R

    2017-08-01

    Combined plyometric and strength training has previously been suggested as a strategy to improve skating performance in ice hockey players. However, the effects of combined plyometric and strength training have not previously been compared with the effects of strength training only. To compare the effects of combined plyometric and strength training on ice hockey players' skating sprint performance with those of strength training only. Eighteen participants were randomly assigned to 2 groups that completed 5 strength-training sessions/wk for 8 wk. One group included plyometric exercises at the start of 3 sessions/wk (PLY+ST), and the other group included core exercises in the same sessions (ST). Tests of 10- and 35-m skating sprints, horizontal jumping, 1-repetition-maximum (1 RM) squat, skating multistage aerobic test (SMAT), maximal oxygen consumption, repeated cycle sprints, and body composition were performed before and after the intervention. The participants increased their 1RM squat, lean mass, and body mass (P plyometric and strength training for 8 wk was superior to strength training alone at improving 10-m on-ice sprint performance in high-level ice hockey players.

  6. Pacing and sprint performance in speed skating during a competitive season.

    Science.gov (United States)

    Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

    2010-06-01

    This study assessed the effect of time spent in several race sectors (S) on finishing time and determined the variance in distribution of skating time and in total race time for official 1000-m sprint races conducted during a competitive season. Total race and sector times for the first 200 m (S1) and the following two 400-m laps (S2 and S3) of 34 female and 31 male elite speed skaters performed during a series of World Cup Meetings were analyzed. Overall, skaters started fast, reached their peak in S2, and slowed down in S3, irrespective of race category considered (eg, rank of athlete, number of race, altitude of rink, starting lane). Regression analyses revealed that spending a shorter fraction of time in the last (women in S3: B = 239.1; P < .0001; men in S3: B = 201.5; P < .0001) but not in the first (women in S1: B = -313.1; P < .0001; men in S1: B = -345.6; P < .0001) race sector is associated with a short total race time. Upper- compared with lower-ranked skaters varied less in competition-to-competition sector and total race times (women: 0.02 to 0.33 vs 0.02 to 0.51; men: 0.01 to 0.15 vs 0.02 to 0.57). This study confirmed that skaters adopted a fast start pacing strategy during official 1000-m sprint races. However, analyses indicate that shortening time in the closing but not in the starting sector is beneficial for finishing fast. In addition, findings suggest that lower-ranked skaters should concentrate training on lowering their competition-to-competition variability in sector times.

  7. Skating crossovers on a motorized flywheel: a preliminary experimental design to test effect on speed and on crossovers.

    Science.gov (United States)

    Smith, Aynsley M; Krause, David A; Stuart, Michael J; Montelpare, William J; Sorenson, Matthew C; Link, Andrew A; Gaz, Daniel V; Twardowski, Casey P; Larson, Dirk R; Stuart, Michael B

    2013-12-01

    Ice hockey requires frequent skater crossovers to execute turns. Our investigation aimed to determine the effectiveness of training crossovers on a motorized, polyethylene high-resistance flywheel. We hypothesized that high school hockey players training on the flywheel would perform as well as their peers training on ice. Participants were 23 male high-school hockey players (age 15-19 years). The study used an experimental prospective design to compare players who trained for 9 sessions on the 22-foot flywheel with players who trained for 9 sessions on a similarly sized on-ice circle. Both groups were compared with control subjects who were randomly selected from the same participant pool as those training on ice. All players were tested before and after their 3-week training regimens, and control subjects were asked to not practice crossovers between testing. Group 1 trained in a hockey training facility housing the flywheel, and group 2 trained in the ice hockey arena where testing occurred. Primary outcome measures tested in both directions were: (a) speed (time in seconds) required to skate crossovers for 3 laps of a marked face-off circle, (b) cadence of skating crossovers on the similarly sized circles, and (c) a repeat interval speed test, which measures anaerobic power. No significant changes were found between groups in on-ice testing before and after training. Among the group 1 players, 7 of 8 believed they benefited from flywheel training. Group 2 players, who trained on ice, did not improve performance significantly over group 1 players. Despite the fact that no significant on-ice changes in performance were observed in objective measures, players who trained on the flywheel subjectively reported that the flywheel is an effective cost-effective alternative to training on ice. This is a relevant finding when placed in context with limited availability of on-ice training.

  8. Influences of a yoga intervention on the postural skills of the Italian short track speed skating team

    Science.gov (United States)

    Brunelle, Jean-François; Blais-Coutu, Sébastien; Gouadec, Kenan; Bédard, Éric; Fait, Philippe

    2015-01-01

    Introduction In preparation for a short track speed skating season, eight men and seven women were given yoga sessions during an 8-week high volume training cycle. The sessions were planned according to the postural aspects specific to short track speed skating technical requirements. Three specific goals were selected for the intervention: 1) to observe whether the practice of yoga as postural training could improve the efficiency and the athlete’s repertoire along the muscular synergies solicited in the short track speed skating specific technique; 2) to enhance and diversify the motor time-on-task of athletes without changing the prescription of other training stimulus; and 3) to lower the risk of injury during periods with high volumes of training. Methods A total of 36 sessions of yoga were given. Three postural tests were administered before and after the intervention with 14 angles analyzed. Non-parametric Wilcoxon test was used to compare angles’ variations. Results The 36 yoga sessions totalized 986 minutes of motor time-on-task, registering a proportion of 30% of the global motor time-on-task of the training cycle. Improvements were found in eleven of the 14 angles measured when comparing pre- and post-postural tests (P-value from 0.01 to 0.005). During the 8 weeks, excepting traumatic injuries due to short track speed skating accidents, no skaters suffered injuries linked to the high volume of training. Following the intervention, coaches noticed, following their on-ice feedbacks, an adjustment in the efficiency of the skating technique, in particular regarding hip dissociation. Conclusion These results suggest that yoga could be inserted into out-of-season training cycles, even in a high volume training cycle. Planned with the decision training tools, it allows athletes to diversify their motor time-on-task by integrating a new functional range of generic movements with the solicitation of neuromuscular synergies related to the specificity of their

  9. The association between changes in speed skating technique and changes in skating velocity.

    Science.gov (United States)

    Noordhof, Dionne A; Foster, Carl; Hoozemans M, J M; de Koning, Jos J

    2014-01-01

    A meaningful association between changes (Δ) in push-off angle or effectiveness (e) and changes in skating velocity (v) has been found during 5000-m races, although no significant association was found between changes in knee (θ0) and trunk angle (θ1) and Δv. It might be that speed skating event, sex, and performance level influence these associations. To study the effect of skating event, sex, and performance level on the association between Δe and Δv and between Δθ0 and Δθ1 and Δv. Video recordings were made from frontal (e) and sagittal views (θ0 and θ1) during 1500- and 5000-m men's and women's World Cup races. Radio-frequency identification tags provided data of v. Skating event influenced the association between Δe and Δv, which resulted in a significant association between Δe and Δv for the 5000-m (β = -0.069, 95% confidence interval [-0.11, -0.030]) but not for the 1500-m (β = -0.011 [-0.032, 0.010]). The association between Δθ0 and Δθ1 and Δv was not significantly influenced by skating event. Sex and performance level did not substantially affect the association between Δe and Δv and between Δθ0 and Δθ1 and Δv. Skating event significantly influenced the association between Δe and Δv; a 1° change in e results in a 0.011-m/s decrease in v during the 1500-m and a 0.069-m/s decrease in v during the 5000-m. Thus, it seems especially important to maintain a small e during the 5000-m.

  10. “Vasaknų dvaro” alaus įvedimo į rinką rinkodaros strategijos formavimas

    OpenAIRE

    Kievišaitė, Inga

    2009-01-01

    Šiame darbe buvo suformuota naujai įsikūrusios įmonės “Vasaknų dvaras” alaus įvedimo į rinką rinkodaros strategija. Darbo tikslas buvo sukurti šią strategiją, o uždaviniai buvo išanalizuoti aplinką, kurioje veikia įmonė bei įmonės galimybes šioje aplinkoje; išsiaiškinti alaus gamybos ir pardavimo subtilybes, apklausiant šios srities ekspertus; pateikti sprendimus dėl produkto pozicionavimo ir rinkodaros komplekso elementų. Darbe buvo naudojamas kokybinis tyrimas – rinkos ekspertų giluminis in...

  11. Real time computer controlled weld skate

    Science.gov (United States)

    Wall, W. A., Jr.

    1977-01-01

    A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.

  12. Evaluation of layback spin in figure skating

    Directory of Open Access Journals (Sweden)

    Jastšenjski Ksenija

    2011-01-01

    Full Text Available Layback spin is considered as one of the most beautiful and elegant spins performed in figure skating. It is also one of the required spins in competitive short program in female category. Different techniques of executing layback spin with variations in changing the positions of free parts of the body, as well as the evaluation of layback spin in accordance with ISU rules and regulations, which have been used in all International Skating Federation competitions since 2004 (World and European championships, Olympic Games are presented in this paper. Due to very difficult position of the body while performing a layback spin, it is essential that the skaters who want to master it should have excellent agility (especially of the spinal column and shoulder and knee joints and balance. Layback spin performance requires significant skating knowledge, so it cannot be performed by beginners. Depending on the fl exibility and creativity, a skater can execute various positions of the head, arms, body and free leg while performing a layback spin. In some cases, these variations can increase the level of difficulty, and in others only the mark given for executing this spin.

  13. 50 CFR 648.320 - Skate FMP review and monitoring.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Skate FMP review and monitoring. 648.320 Section 648.320 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the NE Skate Complex Fisheries §...

  14. 36 CFR 2.20 - Skating, skateboards, and similar devices.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Skating, skateboards, and similar devices. 2.20 Section 2.20 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE PROTECTION, PUBLIC USE AND RECREATION § 2.20 Skating, skateboards, and...

  15. Endurance in speed skating : The development of world records

    NARCIS (Netherlands)

    Kuper, GH; Sterken, E

    2003-01-01

    We analyse the development of world records speed skating from 1893 to 2000 for both men and women. The historical data show that it is likely that the relation between skating speed and distance of the various events is non-linear and converges to a limit value. We pay special attention to

  16. Judging Anomalies at the 2010 Olympics in Men's Figure Skating

    Science.gov (United States)

    Looney, Marilyn A.

    2012-01-01

    The purpose of this study was to determine if the 2010 Olympic figure skating judges had trouble scoring Plushenko and the transitions program component, and if the International Skating Union's (ISU) "corridor" method flagged the same judging anomalies as the Rasch analyses. A 3-facet (skater by program component by judge) Rasch rating…

  17. Connecting Mathematics and Writing Workshop: It's Kinda like Ice Skating

    Science.gov (United States)

    Carter, Susan

    2009-01-01

    Second-grade students struggle with writing about mathematical topics during math class, so the teacher begins to integrate mathematical topics into their Writing Workshop. Content journals are used during math, and students are encouraged to write about personal connections to mathematical situations, as well as incorporate mathematical concepts…

  18. Spatial segregation in eastern North Pacific skate assemblages.

    Directory of Open Access Journals (Sweden)

    Joseph J Bizzarro

    Full Text Available Skates (Rajiformes: Rajoidei are common mesopredators in marine benthic communities. The spatial associations of individual species and the structure of assemblages are of considerable importance for effective monitoring and management of exploited skate populations. This study investigated the spatial associations of eastern North Pacific (ENP skates in continental shelf and upper continental slope waters of two regions: central California and the western Gulf of Alaska. Long-term survey data were analyzed using GIS/spatial analysis techniques and regression models to determine distribution (by depth, temperature, and latitude/longitude and relative abundance of the dominant species in each region. Submersible video data were incorporated for California to facilitate habitat association analysis. We addressed three main questions: 1 Are there regions of differential importance to skates?, 2 Are ENP skate assemblages spatially segregated?, and 3 When skates co-occur, do they differ in size? Skate populations were highly clustered in both regions, on scales of 10s of kilometers; however, high-density regions (i.e., hot spots were segregated among species. Skate densities and frequencies of occurrence were substantially lower in Alaska as compared to California. Although skates are generally found on soft sediment habitats, Raja rhina exhibited the strongest association with mixed substrates, and R. stellulata catches were greatest on rocky reefs. Size segregation was evident in regions where species overlapped substantially in geographic and depth distribution (e.g., R. rhina and Bathyraja kincaidii off California; B. aleutica and B. interrupta in the Gulf of Alaska. Spatial niche differentiation in skates appears to be more pronounced than previously reported.

  19. Spatial segregation in eastern North Pacific skate assemblages.

    Science.gov (United States)

    Bizzarro, Joseph J; Broms, Kristin M; Logsdon, Miles G; Ebert, David A; Yoklavich, Mary M; Kuhnz, Linda A; Summers, Adam P

    2014-01-01

    Skates (Rajiformes: Rajoidei) are common mesopredators in marine benthic communities. The spatial associations of individual species and the structure of assemblages are of considerable importance for effective monitoring and management of exploited skate populations. This study investigated the spatial associations of eastern North Pacific (ENP) skates in continental shelf and upper continental slope waters of two regions: central California and the western Gulf of Alaska. Long-term survey data were analyzed using GIS/spatial analysis techniques and regression models to determine distribution (by depth, temperature, and latitude/longitude) and relative abundance of the dominant species in each region. Submersible video data were incorporated for California to facilitate habitat association analysis. We addressed three main questions: 1) Are there regions of differential importance to skates?, 2) Are ENP skate assemblages spatially segregated?, and 3) When skates co-occur, do they differ in size? Skate populations were highly clustered in both regions, on scales of 10s of kilometers; however, high-density regions (i.e., hot spots) were segregated among species. Skate densities and frequencies of occurrence were substantially lower in Alaska as compared to California. Although skates are generally found on soft sediment habitats, Raja rhina exhibited the strongest association with mixed substrates, and R. stellulata catches were greatest on rocky reefs. Size segregation was evident in regions where species overlapped substantially in geographic and depth distribution (e.g., R. rhina and Bathyraja kincaidii off California; B. aleutica and B. interrupta in the Gulf of Alaska). Spatial niche differentiation in skates appears to be more pronounced than previously reported.

  20. System planning of Nagano Olympic Memorial Arena; Naganoshi Olympic kinen arena

    Energy Technology Data Exchange (ETDEWEB)

    Omae, Y.; Nakamura, M. [Kume Sekkei Co. Ltd., Tokyo (Japan); Hayakawa, M.; Kondo, J. [Kajima Corp., Tokyo (Japan); Ito, T. [Daidan Co. Ltd., Osaka (Japan); Yosoyama, Y. [Suga Engineering Co. Ltd., Tokyo (Japan)

    1999-11-05

    Nagano Olympic Memorial Arena, well known as hosting the Speed Skate Competition in 1998 Winter Olympic Game, is the first multi-purpose facility with 400 m long ice-skate rink in Japan. The superior system for saving energy and resources is the main concept of the arena. This system covers not only the Olympic Game but also multi-functional general usage. The world records and the variety of use are the proof of the accomplishment. (author)

  1. Effect of race distance on muscle oxygenation in short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine M; Laing, Stewart; Cardinale, Marco; Cooper, Chris E

    2013-01-01

    Previous work identified an asymmetry in tissue desaturation changes in the left and right quadriceps muscles during on-ice skating at maximal speed in males. The effect of changing race distance on the magnitude of desaturation or leg asymmetry is unknown. Six elite male skaters (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm) and four elite female skaters (age = 21 ± 4 yr, height = 1.6 ± 0.1 m, mass = 65.2 ± 4.3 kg, midthigh skinfold thickness = 10 ± 1 mm) were studied. Subjects completed time trials over three race distances. Blood lactate concentration and O2 uptake measurements were combined with near-infrared spectroscopy measures of muscle oxygenation (TSI) and blood volume (tHb) in the right and left vastus lateralis. Neither race distance nor gender had a significant effect on the magnitude of maximal muscle desaturation (ΔTSI(max)). Pattern of local changes in tHb during individual laps was dependent upon subtle differences in skating technique used for the different race distances. Linear regression analysis revealed asymmetry between the right and left leg desaturation in males during the final stages of each race distance, but not in females. At all race distances, local muscle desaturation reached maximal values much more quickly than global VO(2peak). The use of wearable near-infrared spectroscopy devices enabled measurement of muscle oxygenation during competitive race simulation, thus providing unique insight into the effects of velocity and technique changes on local muscle oxygenation. This may have implications for training and race pacing in speed skating.

  2. V̇O2 and Muscle Deoxygenation Kinetics During Skating: Comparison Between Slide Board and Treadmill Skating.

    Science.gov (United States)

    Piucco, Tatiane; Soares, Rogério; Diefenthaeler, Fernando; Millet, Guillaume; Murias, Juan

    2017-11-15

    this study aimed to compare the oxygen uptake (V̇O 2 ) kinetics during skating on a treadmill and skating on a slide board and discuss potential mechanisms that might control the V̇O 2 kinetics responses during skating. breath-by-breath pulmonary V̇O 2 and near-infrared spectroscopy-derived muscle deoxygenation ([HHbMb]) were monitored continuously in 12 well-trained young long track speed skaters. On-transient V̇O 2 and [HHbMb] responses to skating on a treadmill and skating on a slide board at 80% of the estimated gas exchange threshold were fitted as mono-exponential function. The signals were time aligned, and the individual [HHbMb]-to-V̇O 2 ratio was calculated as the average value from 20-120 s after exercise starts. the time constants for the adjustment of phase II V̇O 2 (τ V̇O 2 ) and [HHbMb] (τ[HHbMb]) were low and similar between slide board vs. treadmill skating (18.1 ± 3.4 vs. 18.9 ± 3.6 for τ V̇O 2 and 12.6 ± 4.0 vs. 12.4 ± 4.0 s for τ[HHbMb]). The [HHbMb]/V̇O 2 ratio was not different from 1.0 (p > 0.05) in both conditions. the fast V̇O 2 kinetics during skating suggest that chronical adaptation to skating might overcome any possible restriction in leg blood flow during low intensity exercise. The [HHbMb]/V̇O 2 ratio values also suggest a good matching of O 2 delivery to O 2 utilization in trained speed skaters. The similar τ V̇O 2 and τ [HHbMb] values between slide board and treadmill further reinforce the validity of using a slide board for skating testing and training purposes.

  3. Failure of the chassis of roller skates for agonistic figure skating

    Directory of Open Access Journals (Sweden)

    Giorgio Olmi

    2015-04-01

    Full Text Available The subject of this work was to investigate the early failure, which occurred in the chassis of a roller skate for figure skating. The paper deals with the preliminary analysis of the crack and with the integrated approach, which had to be followed to overcome the problem. Literature in the fields of physiology and biomechanics was studied to correctly simulate the load distribution on the chassis. Finite element simulation, experimental stress analysis and analytical modeling of impact phenomena had to be combined together to estimate the entity of dynamic loads and the corresponding state of stress. The analysis led to the determination of the primary cause of failure, bending fatigue, and to the suggestion of a simple solution to improve and optimize the project.

  4. Skate Genome Project: Cyber-Enabled Bioinformatics Collaboration

    Science.gov (United States)

    Vincent, J.

    2011-01-01

    The Skate Genome Project, a pilot project of the North East Cyber infrastructure Consortium, aims to produce a draft genome sequence of Leucoraja erinacea, the Little Skate. The pilot project was designed to also develop expertise in large scale collaborations across the NECC region. An overview of the bioinformatics and infrastructure challenges faced during the first year of the project will be presented. Results to date and lessons learned from the perspective of a bioinformatics core will be highlighted.

  5. Prokaryotic community composition in alkaline-fermented skate (Raja pulchra).

    Science.gov (United States)

    Jang, Gwang Il; Kim, Gahee; Hwang, Chung Yeon; Cho, Byung Cheol

    2017-02-01

    Prokaryotes were extracted from skates and fermented skates purchased from fish markets and a local manufacturer in South Korea. The prokaryotic community composition of skates and fermented skates was investigated using 16S rRNA pyrosequencing. The ranges for pH and salinity of the grinded tissue extract from fermented skates were 8.4-8.9 and 1.6-6.6%, respectively. Urea and ammonia concentrations were markedly low and high, respectively, in fermented skates compared to skates. Species richness was increased in fermented skates compared to skates. Dominant and predominant bacterial groups present in the fermented skates belonged to the phylum Firmicutes, whereas those in skates belonged to Gammaproteobacteria. The major taxa found in Firmicutes were Atopostipes (Carnobacteriaceae, Lactobacillales) and/or Tissierella (Tissierellaceae, Tissierellales). A combination of RT-PCR and pyrosequencing for active bacterial composition showed that the dominant taxa i.e., Atopostipes and Tissierella, were active in fermented skate. Those dominant taxa are possibly marine lactic acid bacteria. Marine bacteria of the taxa Lactobacillales and/or Clostridia seem to be important in alkaline fermentation of skates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. SKATE: a docking program that decouples systematic sampling from scoring.

    Science.gov (United States)

    Feng, Jianwen A; Marshall, Garland R

    2010-11-15

    SKATE is a docking prototype that decouples systematic sampling from scoring. This novel approach removes any interdependence between sampling and scoring functions to achieve better sampling and, thus, improves docking accuracy. SKATE systematically samples a ligand's conformational, rotational and translational degrees of freedom, as constrained by a receptor pocket, to find sterically allowed poses. Efficient systematic sampling is achieved by pruning the combinatorial tree using aggregate assembly, discriminant analysis, adaptive sampling, radial sampling, and clustering. Because systematic sampling is decoupled from scoring, the poses generated by SKATE can be ranked by any published, or in-house, scoring function. To test the performance of SKATE, ligands from the Asetex/CDCC set, the Surflex set, and the Vertex set, a total of 266 complexes, were redocked to their respective receptors. The results show that SKATE was able to sample poses within 2 A RMSD of the native structure for 98, 95, and 98% of the cases in the Astex/CDCC, Surflex, and Vertex sets, respectively. Cross-docking accuracy of SKATE was also assessed by docking 10 ligands to thymidine kinase and 73 ligands to cyclin-dependent kinase. 2010 Wiley Periodicals, Inc.

  7. Bilirubin metabolism in the spiny dogfish, Squalus acanthias, and the small skate, Raja erinacea

    NARCIS (Netherlands)

    Jansen, P. L.; Arias, I. M.

    1977-01-01

    1. The main bilirubin conjugate in bile of spiny dogfish (Squalus Acanthias) and small skate (Raja Erinacea) is bilirubin monoglucuronide. 2. Microsomal preparations from dogfish and small skate liver have similar bilirubin UDPglucuronyltransferase (UDPGT) activity and catalyze the conjugation of

  8. 75 FR 3434 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Amendment 3

    Science.gov (United States)

    2010-01-21

    ...NMFS proposes regulations to implement measures in Amendment 3 to the Northeast Skate Complex Fishery Management Plan (Skate FMP). Amendment 3 was developed by the New England Fishery Management Council (Council) to rebuild overfished skate stocks and implement annual catch limits (ACLs) and accountability measures (AMs) consistent with the requirements of the reauthorized Magnuson-Stevens Fishery Conservation and Management Act (Magnuson-Stevens Act). Amendment 3 would implement a rebuilding plan for smooth skate and establish an ACL and annual catch target (ACT) for the skate complex, total allowable landings (TAL) for the skate wing and bait fisheries, seasonal quotas for the bait fishery, reduced possession limits, in-season possession limit triggers, and other measures to improve management of the skate fisheries. This proposed rule also includes skate fishery specifications for fishing years (FY) 2010 and 2011.

  9. 77 FR 25097 - Fisheries of the Northeastern United States; 2012-2013 Northeast Skate Complex Fishery...

    Science.gov (United States)

    2012-04-27

    ... landings of thorny skate, increase discards, and ultimately hinder the rebuilding of this stock. The... ongoing education and outreach efforts in the skate fishery to improve prohibited species compliance (e.g...

  10. A rapid real-time PCR method to differentiate between mottled skate (Beringraja pulchra) and other skate and ray species.

    Science.gov (United States)

    Kim, Mi-Ra; Kwon, Kisung; Jung, Yoo-Kyung; Kang, Tae Sun

    2018-07-30

    Skates and rays are commercially important fish in South Korea, and among them, Beringraja pulchra has the highest economic value. However, the similar morphological traits among skates and rays are often exploited for seafood fraud. Here, we designed both Beringraja pulchra-specific and skate-universal primer sets, capable of detecting short sequences in the cytochrome oxidase subunit I gene, and developed highly sensitive and reliable quantitative real-time PCR (qPCR) assays to differentiate between Beringraja pulchra and other skate and ray species. AΔCq method based on differences in the amplification efficiency was developed, validated, and then used to confirm the presence of Beringraja pulchra in twenty-six commercial skate products. The averageΔCq value obtained for other skate species (18.94 ± 3.46) was significantly higher than that of Beringraja pulchra (1.18 ± 0.15). For on-site applications, we developed an ultra-fast qPCR assay, allowing for completion of the entire analytical procedure within 30 min. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. 76 FR 28328 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Framework Adjustment 1

    Science.gov (United States)

    2011-05-17

    ... possession limits for the skate wing fishery in order to slow the rate of skate wing landings, so that the... (Council), 50 Water Street, Newburyport, MA 01950. These documents are also available online at http://www... skate wings on board. This ratio, based upon established wing-to-whole weight conversion factor for...

  12. Pediatric fractures during skateboarding, roller skating, and scooter riding.

    Science.gov (United States)

    Zalavras, Charalampos; Nikolopoulou, Georgia; Essin, Daniel; Manjra, Nahid; Zionts, Lewis E

    2005-04-01

    Skateboarding, roller skating, and scooter riding are popular recreational and sporting activities for children and adolescents but can be associated with skeletal injury. The purpose of this study is to describe the frequency and characteristics of fractures resulting from these activities. Fractures from skateboarding, roller skating, and scooter riding compose a considerable proportion of pediatric musculoskeletal injuries. Case series; Level of evidence, 4. Demographic data and injury characteristics were analyzed for all patients who presented to the pediatric fracture clinic of the level I trauma center from January 2001 to May 2002 after sustaining fractures due to skateboarding, roller skating, and scooter riding. Among a total of 2371 fractures, the authors identified 325 fractures (13.7%) that occurred during one of these activities. There were 187 patients (mean age, 13 years; 95% male) who sustained 191 skateboard-related fractures, 64 patients (mean age, 10.8 years; 54% male) who sustained 65 fractures while roller skating, and 66 patients (mean age, 9.7 years; 64% male) who sustained 69 fractures while riding a scooter. The forearm was fractured most often, composing 48.2% of skate-boarding fractures, 63.1% of roller-skating fractures, and 50.7% of fractures due to scooter riding. Of the forearm fractures, 94% were located in the distal third. In the skateboarding group, 10 of 191 (5.2%) fractures were open injuries of the forearm, compared to 6 of 2046 (0.3%) fractures caused by other mechanisms of injury (significant odds ratio, 18.8). Skateboarding, roller-skating, and scooter-riding accidents result in a large proportion of pediatric fractures. An open fracture, especially of the forearm, was more likely to be caused by skateboarding than by other mechanisms of injury. Use of wrist and forearm protective equipment should be considered in all children who ride a skateboard.

  13. Skateboarding: more dangerous than roller skating or in-line skating.

    Science.gov (United States)

    Osberg, J S; Schneps, S E; Di Scala, C; Li, G

    1998-10-01

    To describe the circumstances, severity, and outcomes of skating-related injuries among children admitted to trauma centers. A cross-sectional comparison of roller skaters (n = 154), in-line skaters (n = 190), and skateboarders (n = 254) aged 5 to 19 years who were hospitalized with injuries. Seventy-nine hospitals and pediatric trauma centers participating in the National Pediatric Trauma Registry between October 1988 and April 1997. Three quarters (75.8%) of the study sample were male, nearly half (47.8%) were injured on roads, and more than one third (37.1%) had head injuries. Among skateboarders, 50.8% had head injuries compared with 33.7% of in-line skaters and 18.8% of roller skaters (Pskateboarders were 8 times more likely to be severe or critical compared with roller skaters' injuries and more than 2 times as likely to be severe or critical compared with in-line skaters' injuries. Mean hospital length of stay was 6.0 days for skateboarders, 3.4 days for in-line skaters, and 2.4 days for roller skaters (PSkateboarders were more likely to be male and to be injured on roads than were in-line skaters or roller skaters. Skateboarding-related injuries are more severe and have more serious consequences than roller skating or in-line skating injuries. Research is needed to identify ergonomic and behavioral factors responsible for higher head injury risk to skateboarders, and interventions are needed to reduce the risk.

  14. Reliability and Validity of the Inline Skating Skill Test

    Science.gov (United States)

    Radman, Ivan; Ruzic, Lana; Padovan, Viktoria; Cigrovski, Vjekoslav; Podnar, Hrvoje

    2016-01-01

    This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male) were randomized into two groups (competitive level vs. recreational level). They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8–2.6%] – 2.2% [95% CI: 0.0–4.5%]). In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2–2.4%] – 2.7% [95% CI: 2.1–4.0%]) and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92–0.99] – 0.99 [95% CI: 0.98–1.00]). The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2) revealed that the skill test was able to track changes in skaters’ performances. Competitive-level skaters needed shorter time (24.4–26.4%, all p skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters. Key points Study evaluated the reliability and construct validity of a newly developed inline skating skill test. Evaluated test is a first protocol designed to assess specific inline skating skill. Two groups of amateur skaters with different skating proficiency repeated the skill test in four separate occasions. The results suggest that evaluated test is reliable and valid to evaluate inline skating skill in amateur skaters. PMID:27803616

  15. Validation of a Maximal Incremental Skating Test Performed on a Slide Board: Comparison With Treadmill Skating.

    Science.gov (United States)

    Piucco, Tatiane; Diefenthaeler, Fernando; Soares, Rogério; Murias, Juan M; Millet, Guillaume Y

    2017-11-01

    To investigate the criterion validity of a maximal incremental skating test performed on a slide board (SB). Twelve subelite speed skaters performed a maximal skating test on a treadmill and on a SB. Gas exchange threshold (GET), respiratory compensation point (RCP), and maximal variables were determined. Oxygen uptake ([Formula: see text]) (31.0 ± 3.2 and 31.4 ± 4.1 mL·min -1 ·kg -1 ), percentage of maximal [Formula: see text] ([Formula: see text]) (66.3 ± 4 and 67.7 ± 7.1%), HR (153 ± 14 and 150 ±12 bpm), and ventilation (59.8 ± 11.8 and 57.0 ± 10.7 L·min -1 ) at GET, and [Formula: see text] (42.5 ± 4.4 and 42.9 ± 4.8 mL·min -1 ·kg -1 ), percentage of [Formula: see text] (91.1 ± 3.3 and 92.4 ± 2.1%), heart rate (HR) (178 ± 9 and 178 ± 6 bpm), and ventilation (96.5 ± 19.2 and 92.1 ± 12.7 L·min -1 ) at RCP were not different between skating on a treadmill and on a SB. [Formula: see text] (46.7 ± 4.4 vs 46.4 ±6.1 mL·min -1 ·kg -1 ) and maximal HR (195 ± 6 vs 196 ± 10 bpm) were not significantly different and correlated (r = .80 and r = .87, respectively; P  .8) with athletes' best times on 1500 m. The incremental skating test on a SB was capable to distinguish maximal ([Formula: see text] and HR) and submaximal ([Formula: see text], % [Formula: see text], HR, and ventilation) parameters known to determine endurance performance. Therefore, the SB test can be considered as a specific and practical alternative to evaluate speed skaters.

  16. The impact of dry-land sprint start training on the short track speed skating start.

    Science.gov (United States)

    Haug, William B; Drinkwater, Eric J; Cicero, Nicholas J; Barthell, J Anthony; Chapman, Dale W

    2017-05-05

    This investigation sought to determine the effects of dry-land sprint start training on short track speed skating (STSS) start performance. Nine highly trained short track athletes completed a control period of normal STSS training followed by a four-week training intervention. Before and after the control and intervention periods, athletes performed three electronically timed dry-land and on-ice 14.43 m maximal sprint start efforts. The intervention consisted of two sprint sessions per week consisting of nine electronically timed 14.43 m dry-land sprint starts in addition to normal STSS training. The control period resulted in no substantial change in on-ice start performance (Mean Δ: -0.01 s, 95% Confidence Limits (CL): -0.08 to 0.05 s; Effect Size (ES): -0.05; Trivial) however, a small change was observed in dry-land start performance (Mean Δ: -0.07 s, 95% CL: -0.13 to -0.02 s; ES: -0.49). Following brief specific dry-land sprint start training a small improvement was observed in both on-ice (Mean Δ: -0.07 s, 95% CL: -0.13 to -0.01 s; ES: -0.33) and dry-land (Mean Δ: -0.04 s, 95% CL: -0.09 to 0.00 s; ES: -0.29) start performance. This investigation suggests STSS start performance can be improved through a brief dry-land sprint start training program.

  17. Skate Bathyraja spp. egg predation in the eastern Bering Sea.

    Science.gov (United States)

    Hoff, G R

    2009-01-01

    Predation on skate eggs by snails was examined for three skate species at seven nursery sites in three regions (north, middle and south) of the eastern Bering Sea. Mean predation levels were 6.46% for the Alaska skate Bathyraja parmifera, 2.65% for the Aleutian skate Bathyraja aleutica and 22.25% for the Bering skate Bathyraja interrupta. Predation levels were significantly higher at the middle and north sites than the south sites for all species combined. Predation levels decreased with increasing egg-case densities at all nursery sites, and the highest predation levels occurred where egg-case densities were very low. Predated egg-case density increased with increasing snail densities across all nursery sites examined. The Oregon triton Fusitriton oregonensis was the most abundant snail species at all nursery sites and displayed ability to drill holes in the egg case of B. parmifera. Holes left by predatory snails in egg cases of B. parmifera were significantly larger, and of different shape at the middle site compared to the south site. Holes in B. parmifera were also significantly larger than those in egg cases of B. interrupta across all sites examined. Egg cases of B. aleutica possess surface spines that cover the egg case and may inhibit predation by snails at a greater rate than that of the B. parmifera and B. interrupta, which have a smoother egg-case surface.

  18. Double-push skating versus V2 and V1 skating on uphill terrain in cross-country skiing.

    Science.gov (United States)

    Stöggl, Thomas; Kampel, Wolfgang; Müller, Erich; Lindinger, Stefan

    2010-01-01

    The aims of the study were a) to compare the double-push skating technique with the V2 and the V1 skating techniques on an uphill terrain by a kinematic and kinetic analysis, b) to provide kinetic and kinematic data of the V1 technique at maximal skiing speeds, and c) to test the hypotheses that the double-push skating technique is faster compared with the V2 and the V1 skating techniques. Six elite skiers performed maximum speed sprints over a 60-m uphill section (7 degrees -10 degrees) using the double-push, the V2, and the V1 techniques. Pole and plantar forces and cycle characteristics were analyzed. The double-push skating technique was approximately 4.3% faster (P push and the V2 techniques demonstrated longer cycle lengths, lower cycle rates (both P push technique compared with the V2 technique (all P values push technique compared with the other two techniques (P push techniques compared with the V2 technique stress the mechanical advantage of those techniques on uphill terrain. Because of larger cycle lengths, lower cycle rate, longer recovery times, and equal poling frequency, the double-push technique might be seen as more economic on steep uphills compared with the V1 technique. From a tactical point of view compared with the V1 technique, the double-push technique needs less space due to less lateral displacement, and no technique transitions are necessary when entering and leaving an uphill section.

  19. Common Ice Hockey Injuries and Treatment: A Current Concepts Review.

    Science.gov (United States)

    Mosenthal, William; Kim, Michael; Holzshu, Robert; Hanypsiak, Bryan; Athiviraham, Aravind

    Injuries are common in ice hockey, a contact sport where players skate at high speeds on a sheet of ice and shoot a vulcanized rubber puck in excess of one hundred miles per hour. This article reviews the diagnoses and treatment of concussions, injuries to the cervical spine, and lower and upper extremities as they pertain to hockey players. Soft tissue injury of the shoulder, acromioclavicular joint separation, glenohumeral joint dislocation, clavicle fractures, metacarpal fractures, and olecranon bursitis are discussed in the upper-extremity section of the article. Lower-extremity injuries reviewed in this article include adductor strain, athletic pubalgia, femoroacetabular impingement, sports hernia, medial collateral and anterior cruciate ligament tears, skate bite, and ankle sprains. This review is intended to aid the sports medicine physician in providing optimal sports-specific care to allow their athlete to return to their preinjury level of performance.

  20. After swimming one goes on the ice. Multifunctional complex of sports and leisure uses energetic synergies; Nach dem Schwimmen geht's aufs Eis. Multifunktionaler Sport- und Freizeitkomplex nutzt energetische Synergien

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Frank Peter [Redaktionbuero Archikontext, Berlin (Germany); Vonseelen, Tanja

    2012-11-01

    In Lentpark (Cologne, Federal Republic of Germany) skating and swimming are combined in one building - an unusual combination of use with tradition in Cologne. Recently the bureau Schulitz Architecture + Technology (Braunschweig, Federal Republic of Germany) designed the completed new building of the ice ring and swimming hall. The new building develops the energetic synergies of the coexistence of ice preparation and water heating. The new building was commissioned by KoelnBaeder GmbH (Cologne, Federal Republic of Germany) and is a unique of modern skating arena with spectacular ice overhead way, swimming pool and sauna in Europe.

  1. Wireless instrumented klapskates for long-track speed skating

    NARCIS (Netherlands)

    van der Kruk, E.; den Braver, O.; Schwab, A.L.; van der Helm, F.C.T.; Veeger, H.E.J.

    2016-01-01

    In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a

  2. Wireless instrumented klapskates for long-track speed skating

    NARCIS (Netherlands)

    van der Kruk, E.; den Braver, O.; Schwab, Arend L.; van der Helm, Frans C T; Veeger, H. E J

    2016-01-01

    In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a

  3. Skate Parks as a Context for Adolescent Development

    Science.gov (United States)

    Bradley, Graham L.

    2010-01-01

    All people influence, and are influenced by, the contexts they inhabit. Leisure contexts are no exception. The current research comprised three studies investigating the links between one leisure context, skate parks, and adolescent development. Using interview, observation, and questionnaire methods, the research shed light on several of the…

  4. Towards real-time feedback in high performance speed skating

    NARCIS (Netherlands)

    van der Eb, Jeroen; Zandee, Willem; van den Bogaard, Timo; Geraets, Sjoerd; Veeger, H.E.J.; Beek, Peter; Potthast, Wolfgang; Niehoff, Anja; David, Sina

    2017-01-01

    The aim of the current study is to evaluate several performance indicators to be used as real-time feedback in the coming experiments to enhance performance of elite speeds skaters. Six speed skaters, wearing one IMU per skate, collected data over one full training season to evaluate and pinpoint

  5. Reliability and Validity of the Inline Skating Skill Test.

    Science.gov (United States)

    Radman, Ivan; Ruzic, Lana; Padovan, Viktoria; Cigrovski, Vjekoslav; Podnar, Hrvoje

    2016-09-01

    This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male) were randomized into two groups (competitive level vs. recreational level). They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8-2.6%] - 2.2% [95% CI: 0.0-4.5%]). In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2-2.4%] - 2.7% [95% CI: 2.1-4.0%]) and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92-0.99] - 0.99 [95% CI: 0.98-1.00]). The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2) revealed that the skill test was able to track changes in skaters' performances. Competitive-level skaters needed shorter time (24.4-26.4%, all p skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters.

  6. Ice Sheets & Ice Cores

    DEFF Research Database (Denmark)

    Mikkelsen, Troels Bøgeholm

    Since the discovery of the Ice Ages it has been evident that Earth’s climate is liable to undergo dramatic changes. The previous climatic period known as the Last Glacial saw large oscillations in the extent of ice sheets covering the Northern hemisphere. Understanding these oscillations known....... The first part concerns time series analysis of ice core data obtained from the Greenland Ice Sheet. We analyze parts of the time series where DO-events occur using the so-called transfer operator and compare the results with time series from a simple model capable of switching by either undergoing...

  7. Ice, Ice, Baby!

    Science.gov (United States)

    Hamilton, C.

    2008-12-01

    The Center for Remote Sensing of Ice Sheets (CReSIS) has developed an outreach program based on hands-on activities called "Ice, Ice, Baby". These lessons are designed to teach the science principles of displacement, forces of motion, density, and states of matter. These properties are easily taught through the interesting topics of glaciers, icebergs, and sea level rise in K-8 classrooms. The activities are fun, engaging, and simple enough to be used at science fairs and family science nights. Students who have participated in "Ice, Ice, Baby" have successfully taught these to adults and students at informal events. The lessons are based on education standards which are available on our website www.cresis.ku.edu. This presentation will provide information on the activities, survey results from teachers who have used the material, and other suggested material that can be used before and after the activities.

  8. The Biomechanics of Cranial Forces During Figure Skating Spinning Elements.

    Science.gov (United States)

    Wang, David H; Kostyun, Regina O; Solomito, Matthew J

    2015-03-01

    Several facets of figure skating, such as the forces associated with jumping and landing, have been evaluated, but a comprehensive biomechanical understanding of the cranial forces associated with spinning has yet to be explored. The purpose of this case study was to quantify the cranial rotational acceleration forces generated during spinning elements. This case report was an observational, biomechanical analysis of a healthy, senior-level, female figure skating athlete who is part of an on-going study. A triaxial accelerometer recorded the gravitational forces (G) during seven different spinning elements. Our results found that the layback spin generated significant cranial force and these forces were greater than any of the other spin elements recorded. These forces led to physical findings of ruptured capillaries, dizziness, and headaches in our participant.

  9. Wireless instrumented klapskates for long-track speed skating

    OpenAIRE

    van der Kruk, E.; den Braver, O.; Schwab, Arend L.; van der Helm, Frans C T; Veeger, H. E J

    2016-01-01

    In the current project, we aim to provide speed skaters with real-time feedback on how to improve their skating performance within an individual stroke. The elite skaters and their coaches wish for a system that determines the mechanical power per stroke. The push-off force of the skater is a crucial variable in this power determination. In this study, we present the construction and calibration of a pair of wireless instrumented klapskates that can continuously and synchronously measure this...

  10. Pacing and Performance in Competitive Middle-Distance Speed Skating

    Science.gov (United States)

    Muehlbauer, Thomas; Schindler, Christian; Panzer, Stefan

    2010-01-01

    Data from speed skating during World Cup 1,500-m middle-distance races were analyzed to (a) determine the time/velocity distribution during the race and (b) assess the impact of time spent in several race sectors on performance outcome. Absolute and relative sector times for the first 300 m (S1) and the following three 400-m laps (S2-S4) and their…

  11. Biologic Collagen Cylinder with Skate Flap Technique for Nipple Reconstruction

    Directory of Open Access Journals (Sweden)

    Brian P. Tierney

    2014-01-01

    Full Text Available A surgical technique using local tissue skate flaps combined with cylinders made from a naturally derived biomaterial has been used effectively for nipple reconstruction. A retrospective review of patients who underwent nipple reconstruction using this technique was performed. Comorbidities and type of breast reconstruction were collected. Outcome evaluation included complications, surgical revisions, and nipple projection. There were 115 skate flap reconstructions performed in 83 patients between July 2009 and January 2013. Patients ranged from 32 to 73 years old. Average body mass index was 28.0. The most common comorbidities were hypertension (39.8% and smoking (16.9%. After breast reconstruction, 68.7% of the patients underwent chemotherapy and 20.5% underwent radiation. Seventy-one patients had immediate breast reconstruction with expanders and 12 had delayed reconstruction. The only reported complications were extrusions (3.5%. Six nipples (5.2% in 5 patients required surgical revision due to loss of projection; two patients had minor loss of projection but did not require surgical revision. Nipple projection at time of surgery ranged from 6 to 7 mm and average projection at 6 months was 3–5 mm. A surgical technique for nipple reconstruction using a skate flap with a graft material is described. Complications are infrequent and short-term projection measurements are encouraging.

  12. Biologic collagen cylinder with skate flap technique for nipple reconstruction.

    Science.gov (United States)

    Tierney, Brian P; Hodde, Jason P; Changkuon, Daniela I

    2014-01-01

    A surgical technique using local tissue skate flaps combined with cylinders made from a naturally derived biomaterial has been used effectively for nipple reconstruction. A retrospective review of patients who underwent nipple reconstruction using this technique was performed. Comorbidities and type of breast reconstruction were collected. Outcome evaluation included complications, surgical revisions, and nipple projection. There were 115 skate flap reconstructions performed in 83 patients between July 2009 and January 2013. Patients ranged from 32 to 73 years old. Average body mass index was 28.0. The most common comorbidities were hypertension (39.8%) and smoking (16.9%). After breast reconstruction, 68.7% of the patients underwent chemotherapy and 20.5% underwent radiation. Seventy-one patients had immediate breast reconstruction with expanders and 12 had delayed reconstruction. The only reported complications were extrusions (3.5%). Six nipples (5.2%) in 5 patients required surgical revision due to loss of projection; two patients had minor loss of projection but did not require surgical revision. Nipple projection at time of surgery ranged from 6 to 7 mm and average projection at 6 months was 3-5 mm. A surgical technique for nipple reconstruction using a skate flap with a graft material is described. Complications are infrequent and short-term projection measurements are encouraging.

  13. 76 FR 18505 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Framework Adjustment 1

    Science.gov (United States)

    2011-04-04

    ... Council (Council) to adjust the possession limits for the skate wing fishery in order to slow the rate of... Council (Council), 50 Water Street, Newburyport, MA 01950. These documents are also available online at... skate wings on board. This ratio, based upon established wing-to-whole weight conversion factor for...

  14. Chemical and Nutritional Characteristics of long nose skate (Raja rhina) byproducts from Alaska

    Science.gov (United States)

    Skates have recently become a small commercial fishery in Alaska and along the western United States coast, but have long been associated with bycatch. The fins are marketed as "skate wings" and mainly sold fresh, frozen, and dried or salted and dehydrated for Asian markets. Byproducts generated inc...

  15. 50 CFR 648.322 - Skate allocation, possession, and landing provisions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Skate allocation, possession, and landing provisions. 648.322 Section 648.322 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the NE Skate...

  16. The Olympic 500-m speed skating; the inner-outer lane difference

    NARCIS (Netherlands)

    Kamst, Richard; Kuper, Gerard H.; Sierksma, Gerard

    2010-01-01

    In 1998, the International Skating Union and the International Olympic Committee decided to skate the 500-m twice during World Single Distances Championships, Olympic Games, and World Cups. The decision was based on a study by the Norwegian statistician N. L. Hjort, who showed that in the period

  17. Interjoint coordination of the lower extremities in short-track speed skating.

    Science.gov (United States)

    Khuyagbaatar, Batbayar; Purevsuren, Tserenchimed; Park, Won Man; Kim, Kyungsoo; Kim, Yoon Hyuk

    2017-10-01

    In short-track speed skating, the three-dimensional kinematics of the lower extremities during the whole skating cycle have not been studied. Kinematic parameters of the lower extremities during skating are presented as joint angles versus time. However, the angle-time presentation is not sufficient to describe the relationship between multi-joint movement patterns. Thus, angle-angle presentations were developed and used to describe interjoint coordination in sport activities. In this study, 15 professional male skaters' full body motion data were recorded using a wearable motion capture system during short-track speed skating. We investigated the three-dimensional kinematics of the lower extremities and then established the interjoint coordination between hip-knee and knee-ankle for both legs during the whole skating cycle. The results demonstrate the relationship between multi-joint movements during different phases of short-track speed skating. This study provides fundamentals of the movement mechanism of the lower extremities that can be integrated with physiotherapy to improve skating posture and prevent injuries from repetitive stress since physiological characteristics play an important role in skating performance.

  18. Sensitivity of the International Skating Union's Mathematical Criteria to Flag Potential Scoring Anomalies

    Science.gov (United States)

    Looney, Marilyn A.; Howell, Steven M.

    2015-01-01

    This article describes the "mathematical criteria" employed by the International Skating Union (ISU) to identify potential judging anomalies within competitive figure skating. The mathematical criteria have greater sensitivity to identify scoring anomalies for technical element scores than for the program component scores. This article…

  19. Inner-Outer Lane Advantage in Olympic 1000 Meter Speed Skating

    NARCIS (Netherlands)

    Kamst, Richard; Kuper, Gerard H.; Sierksma, Gerard; Talsma, Bertus G.

    During the Olympic Games and the World Championships Single Distances the 1000m is skated by every skater only one time. However, there may be a difference in skating a 1000m race with a start in the inner and the outer lane that introduces an externality that introduces unfairness. We show that

  20. The Olympic 500-m speed skating; the inner-outer lane difference

    NARCIS (Netherlands)

    Kamst, Richard; Kuper, Gerard H.; Sierksma, Gerard

    In 1998, the International Skating Union and the International Olympic Committee decided to skate the 500-m twice during World Single Distances Championships, Olympic Games, and World Cups. The decision was based on a study by the Norwegian statistician N. L. Hjort, who showed that in the period

  1. Acute physiological responses to recreational in-line skating in young adults.

    Science.gov (United States)

    Orepic, Paula; Mikulic, Pavle; Soric, Maroje; Ruzic, Lana; Markovic, Goran

    2014-01-01

    We examined the physiological responses to in-line skating exercise at self-selected paces in recreationally trained adults. Seven men and 10 women performed in-line skating exercise during which oxygen uptake (VO2) and heart rate (HR) were recorded continuously. Ratings of perceived exertion (RPE) and blood lactate concentration were also obtained at the end of exercise. Furthermore, subjects' peak VO2, peak HR, RPE and gas-exchange thresholds were determined in laboratory settings. The average exercise intensity during in-line skating was 90% of peak HR, 67% of peak VO2, 84% of HR reserve and 64% of VO2 reserve. When expressed as RPE and as metabolic equivalents (METs), the average exercise intensity was 13.1 RPE and 9.4 METs. Overall, these indicators of exercise intensity categorise in-line skating at self-selected paces as a vigorous physical activity. Notably, at similar VO2 values, significantly higher HR (174 ± 16 vs. 156 ± 6 bpm; pskating compared with treadmill running. We conclude that 1. recreational in-line skating induces physiological responses that are sufficient for improving and maintaining cardiovascular fitness in healthy adults, 2. HR- and RPE-based methods for quantifying the exercise intensity during in-line skating may overestimate the actual metabolic load and 3. the derivation of exercise prescriptions for in-line skating should be preferably based on specific (i.e. in-line skating) graded exhaustive exercise test.

  2. Reliability and Validity of the Inline Skating Skill Test

    Directory of Open Access Journals (Sweden)

    Ivan Radman, Lana Ruzic, Viktoria Padovan, Vjekoslav Cigrovski, Hrvoje Podnar

    2016-09-01

    Full Text Available This study aimed to examine the reliability and validity of the inline skating skill test. Based on previous skating experience forty-two skaters (26 female and 16 male were randomized into two groups (competitive level vs. recreational level. They performed the test four times, with a recovery time of 45 minutes between sessions. Prior to testing, the participants rated their skating skill using a scale from 1 to 10. The protocol included performance time measurement through a course, combining different skating techniques. Trivial changes in performance time between the repeated sessions were determined in both competitive females/males and recreational females/males (-1.7% [95% CI: -5.8–2.6%] – 2.2% [95% CI: 0.0–4.5%]. In all four subgroups, the skill test had a low mean within-individual variation (1.6% [95% CI: 1.2–2.4%] – 2.7% [95% CI: 2.1–4.0%] and high mean inter-session correlation (ICC = 0.97 [95% CI: 0.92–0.99] – 0.99 [95% CI: 0.98–1.00]. The comparison of detected typical errors and smallest worthwhile changes (calculated as standard deviations × 0.2 revealed that the skill test was able to track changes in skaters’ performances. Competitive-level skaters needed shorter time (24.4–26.4%, all p < 0.01 to complete the test in comparison to recreational-level skaters. Moreover, moderate correlation (ρ = 0.80–0.82; all p < 0.01 was observed between the participant’s self-rating and achieved performance times. In conclusion, the proposed test is a reliable and valid method to evaluate inline skating skills in amateur competitive and recreational level skaters. Further studies are needed to evaluate the reproducibility of this skill test in different populations including elite inline skaters.

  3. From Morphology to Neural Information: The Electric Sense of the Skate

    Science.gov (United States)

    Camperi, Marcelo; Tricas, Timothy C; Brown, Brandon R

    2007-01-01

    Morphology typically enhances the fidelity of sensory systems. Sharks, skates, and rays have a well-developed electrosense that presents strikingly unique morphologies. Here, we model the dynamics of the peripheral electrosensory system of the skate, a dorsally flattened batoid, moving near an electric dipole source (e.g., a prey organism). We compute the coincident electric signals that develop across an array of the skate's electrosensors, using electrodynamics married to precise morphological measurements of sensor location, infrastructure, and vector projection. Our results demonstrate that skate morphology enhances electrosensory information. Not only could the skate locate prey using a simple population vector algorithm, but its morphology also specifically leads to quick shifts in firing rates that are well-suited to the demonstrated bandwidth of the electrosensory system. Finally, we propose electrophysiology trials to test the modeling scheme. PMID:17571918

  4. First evidence of persistent organic contaminants as potential anthropogenic stressors in the Barndoor Skate Dipturus laevis.

    Science.gov (United States)

    Lyons, Kady; Adams, Douglas H

    2017-03-15

    Although exploited populations of elasmobranchs may be able to recover from fishing pressure, there is little information regarding the Barndoor Skate's ability to cope with other anthropogenic stressors such as organic contaminants (OCs). Legacy OCs were measured in liver, muscle and ova from fourteen Barndoor Skates with mature skates having significantly greater mean concentrations of OCs than immature skates, demonstrating bioaccumulation with age. Using Toxic Equivalency Factors, skates were found to have levels of PCBs that have been shown to elicit negative physiological responses in other fishes and these results highlight the need for future studies to investigate the potential impacts that bioaccumulated organic contaminants have on the recovery and conservation of this vulnerable species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. From morphology to neural information: the electric sense of the skate.

    Directory of Open Access Journals (Sweden)

    Marcelo Camperi

    2007-06-01

    Full Text Available Morphology typically enhances the fidelity of sensory systems. Sharks, skates, and rays have a well-developed electrosense that presents strikingly unique morphologies. Here, we model the dynamics of the peripheral electrosensory system of the skate, a dorsally flattened batoid, moving near an electric dipole source (e.g., a prey organism. We compute the coincident electric signals that develop across an array of the skate's electrosensors, using electrodynamics married to precise morphological measurements of sensor location, infrastructure, and vector projection. Our results demonstrate that skate morphology enhances electrosensory information. Not only could the skate locate prey using a simple population vector algorithm, but its morphology also specifically leads to quick shifts in firing rates that are well-suited to the demonstrated bandwidth of the electrosensory system. Finally, we propose electrophysiology trials to test the modeling scheme.

  6. Captive breeding of the barndoor skate (Dipturus laevis) at the Montreal Biodome, with comparison notes on two other captive-bred skate species.

    Science.gov (United States)

    Parent, Serge; Pépin, Serge; Genet, Jean-Pierre; Misserey, Laurent; Rojas, Salvador

    2008-03-01

    In 1997, the Montreal Biodome obtained five barndoor skates (Dipturus laevis) from the waters off Boston, Massachusetts. Six years later, those specimens began reproducing, and the first egg case was collected in November 2003. Since then, 73 hatchlings have been born and raised. Egg cases were observed year round, and annual fecundity was measured for the first time: one female laid 69 eggs in 2005, 85 in 2006 and 115 in 2007. Egg incubation was longer than believed previously, ranging from 342 to 494 days. Hatching occurred throughout the year. Hatchlings averaged 193 mm total length and 128 mm disk width and weighed 32 g. They were fed krill and diced fish. All but one survived the first month. A photo identification system was useful in recognizing two groups of 10 specimens during their first year, and transponders could be inserted in the wing muscles of 1-year-old skates. Total lengths at birth and at age 2 were similar to the data reported from the wild, suggesting a similar growth pattern in captivity. The reproduction characteristics of the barndoor skate were compared with those of two other skate species currently bred at the Montreal Biodome, the winter skate (Leucoraja ocellata) and the thorny skate (Amblyraja radiata). Zoo Biol 27:145-153, 2008. (c) 2008 Wiley-Liss, Inc.

  7. Relay exchanges in elite short track speed skating.

    Science.gov (United States)

    Hext, Andrew; Heller, Ben; Kelley, John; Goodwill, Simon

    2017-06-01

    In short track speed skating, the relay exchange provides an additional strategic component to races by allowing a team to change the skater involved in the pack race. Typically executed every 1½ laps, it is the belief of skaters and coaches that during this period of the race, time can be gained or lost due to the execution of the relay exchange. As such, the aim of this study was to examine the influence of the relay exchange on a team's progression through a 5000 m relay race. Using data collected from three World Cup relay events during the 2012-2013 season, the time taken to complete the straight for the scenarios with and without the relay exchange were compared at different skating speeds for the corner exit prior to the straight. Overall, the influence of the relay exchange was found to be dependent on this corner exit speed. At slower corner exit speeds (12.01-13.5 m/s), relay exchange straight times were significantly faster than the free skating scenario (P < 0.01). While at faster corner exit speeds (14.01-15 m/s), straight times were significantly slower (P < 0.001). The findings of this study suggest that the current norm of executing relay exchanges every 1½ laps may not be optimal. Instead, varying the frequency of relay exchange execution throughout the race could allow: (1) time to be gained relative to other teams; and (2) facilitate other race strategies by providing an improved opportunity to overtake.

  8. Interannual variability in the skate assemblage on the South Patagonian shelf and slope.

    Science.gov (United States)

    Winter, A; Pompert, J; Arkhipkin, A; Brewin, P E

    2015-12-01

    Observer data from the commercial fishery on the Patagonian shelf and slope around the Falkland Islands (home to an assemblage of >16 skate species (Rajiformes), for which commercial catches have been recorded since 1987), as well as survey data from an area closed to skate target fishing after exploitation, were summarized by species to examine changes in the population status of individual skate species. Total skate catch per unit effort increased significantly in the target fishery since 1994, and four species have made up >85% of all skate catch. Bathyraja brachyurops and Zearaja chilensis increased significantly in catch proportions and abundance from 1994 to 2013. Bathyraja albomaculata and Bathyraja griseocauda decreased significantly before rebounding with trends of increasing abundance. Concurrently, B. brachyurops and Z. chilensis showed decreasing trends in size at 50% maturity in areas where skates continue to be targeted commercially. The increasing abundances and concomitant reductions in size at maturity of B. brachyurops and Z. chilensis suggest either plasticity in life-history traits or a density-dependent growth response to fishing pressure. Bathyraja griseocauda decreased in size at 50% maturity in the area that was closed to skate target fishing, where it was initially larger, but only decreased to the same average size as in the commercially targeted areas. Bathyraja albomaculata and Z. chilensis are IUCN-listed as vulnerable and B. griseocauda is listed as endangered, but their abundance trends since 1994 indicate that these populations are not declining in Falkland waters. © 2015 The Fisheries Society of the British Isles.

  9. The Vibe of Skating; Design and Testing of a Vibro-Tactile Feedback System

    Directory of Open Access Journals (Sweden)

    Arjen J. Jansen

    2018-03-01

    Full Text Available Providing athletes with real-time feedback on their performance is becoming common in many sports, also in speed skating. This research-by-design project aims at finding a tool that allows the speed skater to get real-time feedback on his performance. Speed skaters often mention a so-called “good feeling” when skating behind a better skater. It is the feeling nearly every speed skater is after when skating alone; skate with less power while maintaining the same speed and feeling of ease. A longer push-off phase at a constant cadence has proven to contribute to this ideal situation but is hard for the coach alone to influence this. Therefore, a system was designed that measures the skating cadence and challenges the skater to change his skating stroke by means of vibro-tactile feedback. Four subjects have tested the feedback system. From this test, we concluded that the system provides meaningful feedback towards changing the skating cycle.

  10. Solitary Waves of Ice Loss Detected in Greenland Crustal Motion

    Science.gov (United States)

    Adhikari, S.; Ivins, E. R.; Larour, E. Y.

    2017-12-01

    The annual cycle and secular trend of Greenland mass loading are well recorded in measurements of solid Earth deformation. While bedrock vertical displacements are in phase with loading as inferred from space observations, horizontal motions have received almost no attention. The horizontal bedrock displacements can potentially track the spatiotemporal detail of mass changes with great fidelity. Our analysis of Greenland crustal motion data reveals that a significant excitation of horizontal amplitudes occurs during the intense Greenland melting. A suite of space geodetic observations and climate reanalysis data cannot explain these large horizontal displacements. We discover that solitary seasonal waves of substantial mass transport traveled through Rink Glacier in 2010 and 2012. We deduce that intense summer melting enhanced either basal lubrication or shear softening, or both, causing the glacier to thin dynamically. The newly routed upstream sublglacial water was likely to be both retarded and inefficient, thus providing a causal mechanism for the prolonged ice transport to continue well into the winter months. As the climate continues to produce increasingly warmer spring and summer, amplified seasonal waves of mass transport may become ever more present in years of future observations. Increased frequency of amplified seasonal mass transport may ultimately strengthen the Greenland's dynamic ice mass loss, a component of the balance that will have important ramifications for sea level rise. This animation shows a solitary wave passing through Rink Glacier, Greenland, in 2012, recorded by the motion of a GPS station (circle with arrow). Darker blue colors within the flow indicate mass loss, red colors show mass gain. The star marks the center of the wave. Credit: NASA/JPL-Caltech

  11. Effect of ice surface size on collision rates and head impacts at the World Junior Hockey Championships, 2002 to 2004.

    Science.gov (United States)

    Wennberg, Richard

    2005-03-01

    To determine if collision rates and head impacts in elite junior hockey differed between games played on the small North American ice surface (85 ft wide), an intermediate-size Finnish ice surface (94 ft wide), and the large standard international ice surface (100 ft wide). Videotape analysis of all games involving Team Canada from the 2002 (large ice, Czech Republic), 2003 (small ice, Canada), and 2004 (intermediate ice, Finland) World Junior Championships. All collisions were counted and separated into various categories (volitional player/player bodychecks, into boards or open ice, plus accidental/incidental player/boards, player/ice, head/stick, head/puck). Further subdivisions included collisions involving the head directly or indirectly and notably severe head impacts. Small, intermediate, and large ice surface mean collisions/game, respectively, were 295, 258, 222, total collisions; 251, 220, 181, volitional bodychecks; 126, 115, 88, into boards; 125, 106, 93, open ice; 71, 52, 44, total head; 44, 36, 30, indirect head; 26, 16, 13, direct head; and 1.3, 0.5, 0.3, severe head (P < 0.05 for small-intermediate ice and intermediate-large ice differences in total collisions; P < 0.005 for small-large ice difference; P < 0.05 for small-intermediate ice differences in head impacts; P < 0.01 for small-large ice differences in total and severe head impacts). There is a significant inverse correlation between ice size and collision rates in elite hockey, including direct, indirect, and severe head impacts. These findings suggest that uniform usage of the larger international rinks could reduce the risk of injury, and specifically, concussions in elite hockey by decreasing the occurrence of collisions and head impacts.

  12. Estado de fluxo em praticantes de escalada e skate downhill Flow state in climbing and skate downhill practitioners

    Directory of Open Access Journals (Sweden)

    Lenamar Fiorese Vieira

    2011-12-01

    Full Text Available Este estudo teve como objetivo investigar a prevalência do estado de fluxo em praticantes de escalada e skate downhill. Foram sujeitos 37 praticantes. Como instrumentos foram utilizadas a Escala de Motivação para o Esporte (SMS e a Ficha de Percepção de Capacidade de Realização da Tarefa. A coleta foi realizada nos locais de prática das atividades. Para análise dos dados foram utilizados Shapiro-Wilk, Mann-Whitney e Anova one-way. Os resultados demonstraram: 4,54% dos praticantes de escalada e 13,33% de skate downhill atingiram os elementos do estado de fluxo; a maioria dos praticantes situou-se entre a fase de fluxo estados de ansiedade ou relaxamento e exaltação ou controle; o tempo de prática contribuiu para atingir metas e estado de fluxo. Concluiu-se: o estado de Fluxo teve baixa incidência nos praticantes, havendo interferência da falta de equilíbrio entre percepção das metas, habilidades e desafios nas atividades de aventura.This study aimed to investigate the prevalence of Flow state in climbing and skate downhill practitioners. The subjects were 37 practitioners. The instruments used were the Sport Motivations Scale (SMS and Perception Capacity Achievement Task Form. Data collection was performed at the locations of these practice activities. For data analysis it was used the Shapiro-Wilk, Mann-Whitney and Anova one-way. The results showed: 4,54% of climbing practitioners and 13,33% of skate-downhill reached flow state elements; most of practitioners prevailed between the flow phase of anxiety or relaxation and phase of exaltation or control; and the practice time contributed to reach goals and Flow State. It was concluded that the Flow State had low prevalence in practitioners with interference of lack of balance between the perception of the goals, skills and challenges in the adventure activities.

  13. Progressive hypoxia decouples activity and aerobic performance of skate embryos.

    Science.gov (United States)

    Di Santo, Valentina; Tran, Anna H; Svendsen, Jon C

    2016-01-01

    Although fish population size is strongly affected by survival during embryonic stages, our understanding of physiological responses to environmental stressors is based primarily on studies of post-hatch fishes. Embryonic responses to acute exposure to changes in abiotic conditions, including increase in hypoxia, could be particularly important in species exhibiting long developmental time, as embryos are unable to select a different environment behaviourally. Given that oxygen is key to metabolic processes in fishes and aquatic hypoxia is becoming more severe and frequent worldwide, organisms are expected to reduce their aerobic performance. Here, we examined the metabolic and behavioural responses of embryos of a benthic elasmobranch fish, the little skate (Leucoraja erinacea), to acute progressive hypoxia, by measuring oxygen consumption and movement (tail-beat) rates inside the egg case. Oxygen consumption rates were not significantly affected by ambient oxygen levels until reaching 45% air saturation (critical oxygen saturation, S crit). Below S crit, oxygen consumption rates declined rapidly, revealing an oxygen conformity response. Surprisingly, we observed a decoupling of aerobic performance and activity, as tail-beat rates increased, rather than matching the declining metabolic rates, at air saturation levels of 55% and below. These results suggest a significantly divergent response at the physiological and behavioural levels. While skate embryos depressed their metabolic rates in response to progressive hypoxia, they increased water circulation inside the egg case, presumably to restore normoxic conditions, until activity ceased abruptly around 9.8% air saturation.

  14. Ice Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice...

  15. 76 FR 66856 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Secretarial...

    Science.gov (United States)

    2011-10-28

    ... still protecting skates from overfishing. DATES: Effective November 28, 2011, through April 30, 2012... conservation concerns (e.g., overfishing), and Magnuson-Stevens Act emergency actions have been used in the...

  16. The effects of the arm swing on biomechanical and physiological aspects of roller ski skating.

    Science.gov (United States)

    Hegge, Ann Magdalen; Ettema, Gertjan; de Koning, Jos J; Rognstad, Asgeir Bakken; Hoset, Martin; Sandbakk, Øyvind

    2014-08-01

    This study analyzed the biomechanical and physiological effects of the arm swing in roller ski skating, and compared leg-skating (i.e. ski skating without poles) using a pronounced arm swing (SWING) with leg-skating using locked arms (LOCKED). Sixteen elite male cross-country skiers performed submaximal stages at 10, 15 and 20kmh(-1) on a 2% inclined treadmill in the two techniques. SWING demonstrated higher peak push-off forces and a higher force impulse at all speeds, but a longer cycle length only at the highest speed (all Pskating increases the ski forces and aerobic energy cost at low and moderate speeds, whereas the greater forces at high speed lead to a longer cycle length and smaller anaerobic contribution. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Three-dimensional Force and Kinematic Interactions in V1 Skating at High Speeds.

    Science.gov (United States)

    Stöggl, Thomas; Holmberg, Hans-Christer

    2015-06-01

    To describe the detailed kinetics and kinematics associated with use of the V1 skating technique at high skiing speeds and to identify factors that predict performance. Fifteen elite male cross-country skiers performed an incremental roller-skiing speed test (Vpeak) on a treadmill using the V1 skating technique. Pole and plantar forces and whole-body kinematics were monitored at four submaximal speeds. The propulsive force of the "strong side" pole was greater than that of the "weak side" (P skating at high speeds. The faster skiers exhibit more symmetric leg motion on the "strong" and "weak" sides, as well as more synchronized poling. With respect to methods, the pressure insoles and three-dimensional kinematics in combination with the leg push-off model described here can easily be applied to all skating techniques, aiding in the evaluation of skiing techniques and comparison of effectiveness.

  18. The physiological and biomechanical contributions of poling to roller ski skating.

    Science.gov (United States)

    Sandbakk, Øyvind; Ettema, Gertjan; Holmberg, Hans-Christer

    2013-08-01

    Poling is considered to make a significant contribution to cross-country skiing with the skating technique. To better understand this contribution, the current investigation compared roller ski skating on a treadmill with the so-called G3 skating technique with (G3-P) and without poling (G3-NP). Seven male elite skiers performed 5-min submaximal tests at 8, 12, and 15 km h(-1), as well as an incremental test to exhaustion with both techniques on a 5 % incline. Ventilatory variables were assessed by open-circuit indirect calorimetry and three-dimensional kinematics analyzed using the Qualisys Pro Reflex system. G3-P was associated with approximately 15 % higher peak velocity and 10 % higher peak oxygen uptake than G3-NP in the incremental test (both P skating, specifically by enhancing peak oxygen uptake, skiing efficiency and associated biomechanical variables.

  19. Ice Cream

    NARCIS (Netherlands)

    Scholten, E.

    2014-01-01

    Ice cream is a popular dessert, which owes its sensorial properties (mouth feel) to its complex microstructure. The microstructure is a result of the combination of the ingredients and the production process. Ice cream is produced by simultaneous freezing and shearing of the ice cream mix, which

  20. Ice targets

    International Nuclear Information System (INIS)

    Pacheco, C.; Stark, C.; Tanaka, N.; Hodgkins, D.; Barnhart, J.; Kosty, J.

    1979-12-01

    This report presents a description of ice targets that were constructed for research work at the High Resolution Spectrometer (HRS) and at the Energetic Pion Channel and Spectrometer (EPICS). Reasons for using these ice targets and the instructions for their construction are given. Results of research using ice targets will be published at a later date

  1. In situ observations of a possible skate nursery off the western Antarctic Peninsula.

    Science.gov (United States)

    Amsler, M O; Smith, K E; McClintock, J B; Singh, H; Thatje, S; Vos, S C; Brothers, C J; Brown, A; Ellis, D; Anderson, J; Aronson, R B

    2015-06-01

    A dense aggregation of skate egg cases was imaged during a photographic survey of the sea floor along the western Antarctic Peninsula in November 2013. Egg cases were noted in a narrow band between 394 and 443 m depth. Although some skate species in other oceans are known to utilize restricted areas to deposit eggs in great numbers, such nurseries have not been described in the Southern Ocean. © 2015 The Fisheries Society of the British Isles.

  2. Anti-Runaway Prevention System with Wireless Sensors for Intelligent Track Skates at Railway Stations.

    Science.gov (United States)

    Jiang, Chaozhe; Xu, Yibo; Wen, Chao; Chen, Dilin

    2017-12-19

    Anti-runaway prevention of rolling stocks at a railway station is essential in railway safety management. The traditional track skates for anti-runaway prevention of rolling stocks have some disadvantages since they are operated and monitored completely manually. This paper describes an anti-runaway prevention system (ARPS) based on intelligent track skates equipped with sensors and real-time monitoring and management system. This system, which has been updated from the traditional track skates, comprises four parts: intelligent track skates, a signal reader, a database station, and a monitoring system. This system can monitor the real-time situation of track skates without changing their workflow for anti-runaway prevention, and thus realize the integration of anti-runaway prevention information management. This system was successfully tested and practiced at Sunjia station in Harbin Railway Bureau in 2014, and the results confirmed that the system showed 100% accuracy in reflecting the usage status of the track skates. The system could meet practical demands, as it is highly reliable and supports long-distance communication.

  3. Anti-Runaway Prevention System with Wireless Sensors for Intelligent Track Skates at Railway Stations

    Directory of Open Access Journals (Sweden)

    Chaozhe Jiang

    2017-12-01

    Full Text Available Anti-runaway prevention of rolling stocks at a railway station is essential in railway safety management. The traditional track skates for anti-runaway prevention of rolling stocks have some disadvantages since they are operated and monitored completely manually. This paper describes an anti-runaway prevention system (ARPS based on intelligent track skates equipped with sensors and real-time monitoring and management system. This system, which has been updated from the traditional track skates, comprises four parts: intelligent track skates, a signal reader, a database station, and a monitoring system. This system can monitor the real-time situation of track skates without changing their workflow for anti-runaway prevention, and thus realize the integration of anti-runaway prevention information management. This system was successfully tested and practiced at Sunjia station in Harbin Railway Bureau in 2014, and the results confirmed that the system showed 100% accuracy in reflecting the usage status of the track skates. The system could meet practical demands, as it is highly reliable and supports long-distance communication.

  4. Push-off forces in elite short-track speed skating.

    Science.gov (United States)

    van der Kruk, Eline; Reijne, Marco M; de Laat, Bjorn; Veeger, DirkJan H E J

    2018-05-30

    This study performed an analysis of the push-off forces of elite-short-track speed skaters using a new designed instrumented short-track speed skate with the aim to improve short-track skating performance. Four different skating strokes were distinguished for short-track speed skaters at speed. The strokes differed in stroke time, force level in both normal and lateral directions, and the centre of pressure (COP) on the blade. Within the homogeneous group of male elite speed skaters (N = 6), diversity of execution of the force patterns in the four phases of skating was evident, while skating at the same velocities. The male participants (N = 6) with a better personal record (PR) kept the COP more to the rear of their blades while hanging into the curve (r = 0.82, p < 0.05), leaving the curve (r = 0.86, p < 0.05), and entering the straight (r = 0.76, p < 0.10). Furthermore, the male skaters with a better PR showed a trend of a lower lateral peak force while entering the curve (r = 0.74, p < 0.10). Females showed a trend towards applying higher body weight normalised lateral forces than the males, while skating at imposed lower velocities.

  5. Curvature singularity and film-skating during drop impact

    Science.gov (United States)

    Duchemin, Laurent; Josserand, Christophe

    2011-09-01

    We study the influence of the surrounding gas in the dynamics of drop impact on a smooth surface. We use an axisymmetric model for which both the gas and the liquid are incompressible; lubrication regime applies for the gas film dynamics and the liquid viscosity is neglected. In the absence of surface tension a finite time singularity whose properties are analysed is formed and the liquid touches the solid on a circle. When surface tension is taken into account, a thin jet emerges from the zone of impact, skating above a thin gas layer. The thickness of the air film underneath this jet is always smaller than the mean free path in the gas suggesting that the liquid film eventually wets the surface. We finally suggest an aerodynamical instability mechanism for the splash.

  6. Peak effect versus skating in high-temperature nanofriction

    Science.gov (United States)

    Zykova-Timan, T.; Ceresoli, D.; Tosatti, E.

    2007-03-01

    The physics of sliding nanofriction at high temperature near the substrate melting point, TM, is so far unexplored. We conducted simulations of hard tips sliding on a prototype non-melting surface, NaCl(100), revealing two distinct and opposite phenomena for ploughing and for grazing friction in this regime. We found a frictional drop close to TM for deep ploughing and wear, but on the contrary a frictional rise for grazing, wearless sliding. For both phenomena, we obtain a fresh microscopic understanding, relating the former to `skating' through a local liquid cloud, and the latter to linear response properties of the free substrate surface. We argue that both phenomena occur more generally on surfaces other than NaCl and should be pursued experimentally. Most metals, in particular those possessing one or more close-packed non-melting surfaces, such as Pb, Al or Au(111), are likely to behave similarly.

  7. Validity of Lactate Thresholds in Inline Speed Skating.

    Science.gov (United States)

    Hecksteden, Anne; Heinze, Tobias; Faude, Oliver; Kindermann, Wilfried; Meyer, Tim

    2015-09-01

    Lactate thresholds are commonly used as estimates of the highest workload where lactate production and elimination are in equilibrium (maximum lactate steady state [MLSS]). However, because of the high static load on propulsive muscles, lactate kinetics in inline speed skating may differ significantly from other endurance exercise modes. Therefore, the discipline-specific validity of lactate thresholds has to be verified. Sixteen competitive inline-speed skaters (age: 30 ± 10 years; training per week: 10 ± 4 hours) completed an exhaustive stepwise incremental exercise test (start 24 km·h, step duration 3 minutes, increment 2 km·h) to determine individual anaerobic threshold (IAT) and the workload corresponding to a blood lactate concentration of 4 mmol·L (LT4) and 2-5 continuous load tests of (up to) 30 minutes to determine MLSS. The IAT and LT4 correlated significantly with MLSS, and the mean differences were almost negligible (MLSS 29.5 ± 2.5 km·h; IAT 29.2 ± 2.0 km·h; LT4 29.6 ± 2.3 km·h; p > 0.1 for all differences). However, the variability of differences was considerable resulting in 95% limits of agreement in the upper range of values known from other endurance disciplines (2.6 km·h [8.8%] for IAT and 3.1 km·h [10.3%] for LT4). Consequently, IAT and LT4 may be considered as valid estimates of the MLSS in inline speed skating, but verification by means of a constant load test should be considered in cases of doubt or when optimal accuracy is needed (e.g., in elite athletes or scientific studies).

  8. Jaunimo užimtumas ir jų įsitraukimą į darbo rinką lengvinančios priemonės

    OpenAIRE

    Kvedaraitė, Nida; Repečkienė, Aušra; Glinskienė, Rasa; Žvirelienė, Renata

    2012-01-01

    Pastarųjų dešimtmečių vieno svarbiausių fenomeno – globalizacijos – transformacinės galimybės stipriai skverbiasi į ekonominio-socialinio gyvenimo sritis ir neišvengiamai lemia darbo rinkos pokyčius, kelia naujus reikalavimus ir iššūkius visuomenei, susidedančiai iš skirtingų socialinių grupių. Viena jautriausių socialinių grupių yra jaunimas, kurio integracija į darbo rinką tampa bene aktualiausia šių dienų ekonomine, socialine ir politine problema. Europos Komisijos komunikato „Judus jaunim...

  9. Sea Ice

    Science.gov (United States)

    Perovich, D.; Gerland, S.; Hendricks, S.; Meier, Walter N.; Nicolaus, M.; Richter-Menge, J.; Tschudi, M.

    2013-01-01

    During 2013, Arctic sea ice extent remained well below normal, but the September 2013 minimum extent was substantially higher than the record-breaking minimum in 2012. Nonetheless, the minimum was still much lower than normal and the long-term trend Arctic September extent is -13.7 per decade relative to the 1981-2010 average. The less extreme conditions this year compared to 2012 were due to cooler temperatures and wind patterns that favored retention of ice through the summer. Sea ice thickness and volume remained near record-low levels, though indications are of slightly thicker ice compared to the record low of 2012.

  10. Ice-ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

    Science.gov (United States)

    Chauché, N.; Hubbard, A.; Gascard, J.-C.; Box, J. E.; Bates, R.; Koppes, M.; Sole, A.; Christoffersen, P.; Patton, H.

    2014-08-01

    Warm, subtropical-originating Atlantic water (AW) has been identified as a primary driver of mass loss across the marine sectors of the Greenland Ice Sheet (GrIS), yet the specific processes by which this water mass interacts with and erodes the calving front of tidewater glaciers is frequently modelled and much speculated upon but remains largely unobserved. We present a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estimation from Rink and Store glaciers, two major marine outlets draining the western sector of the GrIS during 2009 and 2010. We characterise the main water bodies present and interpret their interaction with their respective calving fronts. We identify two distinct processes of ice-ocean interaction which have distinct spatial and temporal footprints: (1) homogenous free convective melting which occurs across the calving front where AW is in direct contact with the ice mass, and (2) localised upwelling-driven melt by turbulent subglacial runoff mixing with fjord water which occurs at distinct injection points across the calving front. Throughout the study, AW at 2.8 ± 0.2 °C was consistently observed in contact with both glaciers below 450 m depth, yielding homogenous, free convective submarine melting up to ~200 m depth. Above this bottom layer, multiple interactions are identified, primarily controlled by the rate of subglacial fresh-water discharge which results in localised and discrete upwelling plumes. In the record melt year of 2010, the Store Glacier calving face was dominated by these runoff-driven plumes which led to a highly crenulated frontal geometry characterised by large embayments at the subglacial portals separated by headlands which are dominated by calving. Rink Glacier, which is significantly deeper than Store has a larger proportion of its submerged calving face exposed to AW, which results in a uniform, relatively flat overall frontal geometry.

  11. Cooper-pair and Bose-Einstein condensations in two dimensions: A critical analysis based on the Nozieres and Schmitt-Rink formalism

    International Nuclear Information System (INIS)

    Tokumitu, A.; Miyake, K.; Yamada, K.

    1993-01-01

    The crossover between the Cooper-pair condensation and the Bose-Einstein condensation of ''di-electronic'' molecules in two-dimensional superconductors is investigated in detail on the basis of the Nozieres and Schmitt-Rink formalism. It is shown that temperature dependence of the chemical potential μ so calculated is classified into two classes as decreasing temperatures; i.e., class (a) where μ approaches the point of Bose-Einstein condensation of two-dimensional ideal Bose gas of ''di-electronic'' molecules, and class (b) where μ diverges positively along the line of BCS-type mean-field pair condensation. This feature is rather universal irrespective of strength V of the attractive interaction of the s-wave type. While the former class (a) has been found by Schmitt-Rink, Varma, and Ruckenstein, existence of the latter class (b) is recognized here. In the case where V is fixed, class (a) is realized for electron number density N smaller than N cr , which is an increasing function of V, and class (b) is realized for N larger than N cr . If N much-gt N cr in particular, there exists a regime, where the Fermi-liquid-like description is valid, between the BCS-type mean-field transition temperature and the Fermi temperature. In the situation where V is changed with N being fixed, low-temperature states for the strong-coupling case belong to class (a) while those for the weak-coupling case belong to class (b). Therefore, with decreasing V, the chemical potential μ(T), at temperatures far below the Fermi temperature, shows a discontinuous jump at V=V cr (N) corresponding to the transition from class (a) to (b)

  12. Trends and Variability of the Outdoor Skating Season in Canada during 1951-2005

    Science.gov (United States)

    Damyanov, Nikolay Nikolaev

    Climate change affects a range of human activities, including one of Canada's prime sources of entertainment: ice skating. Whether done recreationally or as hockey, its outdoor component is heavily dependent on weather and climate. Based on information obtained from public works officials from various Canadian cities, I have established a meteorological criterion for the initiation of an outdoor skating season (OSS) as the last day in a sequence of the first three consecutive fall/winter days with a maximum temperature below -5 °C. In addition, I derive a proxy of the OSS length, defined as the total number of days with a maximum temperature below -5 °C after the OSS start date and before the start of March. Using these filters, I have extracted the start dates and the lengths of the OSS for each year during the fifty-five year period 1951-2005 from a comprehensive daily temperature dataset (Vincent et al., 2002). For each station, I created time series of both the OSS start dates and OSS lengths, and calculated the magnitude, sign and statistical significance of the slopes of the best-fit lines to each time series. In order to establish a relationship of the OSS with large-scale climate patterns, I grouped stations into six climatic regions. Depending on location, I then tested each region for correlation with the Pacific North-American teleconnection pattern (PNA) or the North Atlantic Oscillation (NAO), using a composite analysis method. Lastly, I removed the signal due to these climate fluctuations from the OSS start date and length trends in order to determine how much of the variability was caused by these interannual climate oscillations. The results of the study indicate that most stations in British Columbia and southwest Alberta, as well as these in the southern Ontario/Quebc region have witnessed a progressively later onset of the OSS over time. The Prairies, northwest Canada, and some Maritime locales show the opposite trend, although the magnitudes

  13. 75 FR 73981 - Fisheries of the Exclusive Economic Zone Off Alaska; Big Skate in the Central Regulatory Area of...

    Science.gov (United States)

    2010-11-30

    ...NMFS is prohibiting retention of big skate in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2010 total allowable catch (TAC) of big skate in the Central Regulatory Area of the GOA has been reached.

  14. 78 FR 27863 - Fisheries of the Exclusive Economic Zone Off Alaska; Big Skate in the Central Regulatory Area of...

    Science.gov (United States)

    2013-05-13

    ...NMFS is prohibiting retention of big skate in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2013 total allowable catch of big skate in the Central Regulatory Area of the GOA has been reached.

  15. 77 FR 75399 - Fisheries of the Exclusive Economic Zone Off Alaska; Big Skate in the Central Regulatory Area of...

    Science.gov (United States)

    2012-12-20

    ...NMFS is prohibiting retention of big skate in the Central Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2012 total allowable catch of big skate in the Central Regulatory Area of the GOA has been reached.

  16. 75 FR 73982 - Fisheries of the Exclusive Economic Zone Off Alaska; Longnose Skate in the Western Regulatory...

    Science.gov (United States)

    2010-11-30

    ...NMFS is prohibiting retention of longnose skate in the Western Regulatory Area of the Gulf of Alaska (GOA). This action is necessary because the 2010 total allowable catch (TAC) of longnose skate in the Western Regulatory Area of the GOA has been reached.

  17. Modern technology of the specialists in the figure skating on ice.

    Directory of Open Access Journals (Sweden)

    Medvedeva I.M.

    2010-12-01

    Full Text Available The process of teaching of future specialists is presented in the complex - coordinated types of sport in higher educational establishments, as a system of knowledge for future teachers-trainers. Basic approaches are exposed in forming of their pedagogical trade. It is certain that they are based on the study of the modern system of preparation of sportsmen, built taking into account features and their progress trends, directed on achievement of maximally possible sporting result.

  18. Evaluating the injury incidence from skate shoes in the United States.

    Science.gov (United States)

    Ruth, Erin; Shah, Binisa; Fales, Willliam

    2009-05-01

    The goals of this study were to evaluate whether the increased use of skate shoes may lead to an increase in injuries for children and adolescents aged 5 to 14 years in the United States and to describe the types of injuries reported by emergency departments as a result of skate shoe use. Retrospective analysis of the National Electronic Injury Surveillance System database from January 1, 2002 to December 31, 2006 for injuries resulting from footwear in children and adolescents aged 5 to 14 years. Injuries resulting from skate shoe use were identified by manual review of the data. For the 5-year period, an estimated 3525 patients between 5 and 14 years of age were treated in United States emergency departments for injuries resulting from skate shoe use. The percentage of injuries resulting from skate shoes of total footwear-related injuries varied by year, however, with 1.0%, 1.0%, 0.8%, and 1.9% occurring in 2002 to 2005, respectively, and 11.8% occurring in 2006. This substantial increase in 2006 accounts for 73.6% of skate shoe-related injuries and is statistically significant (chi, P = skate shoe sales, with a correlation coefficient of 0.9982.Most of the injured children and adolescents were white, and there was a slight, nonsignificant predominance of boys. Most injuries in all 5-year-olds were fractures (46.7%), followed by contusions (17.9%) and sprains (17.2%). The most frequent site of fracture was the forearm (38.4%), followed by the wrist (35.1%) and the leg (14.9%). Other injuries included lacerations (7.3%), concussions (6.6%), internal organ injuries (0.9%), hematomas (0.2%), dislocations (0.2%), and injuries not otherwise specified (3.1%). Based on national estimates, 104 (0.01%) patients required admission to the hospital. No injuries recorded in the National Electronic Injury Surveillance System database resulted in death. As the first study analyzing injury rates as a result of skate shoe use in the United States, this study demonstrated a recent

  19. Numerical and functional responses of intestinal helminths in three rajid skates: evidence for competition between parasites?

    Science.gov (United States)

    Randhawa, Haseeb S

    2012-11-01

    Host-parasite interactions generally involve communities of parasites. Within these communities, species will co-exist and/or interact with one another in a manner either benefiting the species involved or to the detriment of one or more of the species. At the level of helminth infracommunities, evidence for intra- and inter-specific competition includes numerical responses, i.e. those regulating helminth intensity of infection, and functional responses, i.e. where the presence of competitors modifies the realised niche of infrapopulations. The objectives of this study are to assess the numerical and functional responses of helminths in infracommunities from 3 rajid skates using general linear models. Despite a lack of numerical responses, functional responses to intra- and inter-specific interactions were observed. A positive correlation between the number of individuals in an infrapopulation and its niche breadth (functional response) was observed for the tapeworms Pseudanthobothrium spp. and Echeneibothrium spp., in all their respective hosts, and for the nematode Pseudanisakis sp. in the little skate. Evidence for inter-specific competition includes niche shifts in Pseudanthobothrium purtoni (ex little skate) and Pseudanisakis sp. (ex thorny skate) in the presence of Pseudanisakis sp. and the tapeworm Grillotia sp., respectively. These results are consistent with other studies in providing evidence for competition between helminths of skates.

  20. Molecular cloning and characterization of preproorexin in winter skate (Leucoraja ocellata).

    Science.gov (United States)

    MacDonald, Erin E; Volkoff, Hélène

    2010-12-01

    A 815 base pairs (bp) cDNA encoding for preproorexin (preproOX) was cloned in winter skate, a cartilaginous fish. Winter skate preproOX is 159 amino acids (aa) long and contains a 34 aa orexin A and 28 aa orexin B. The amino acid sequence of winter skate preproOX is more similar to tetrapod preproOXs (36-40% identity) than teleost preproOXs (23-33% identity). Whereas orexin B appears relatively well conserved among vertebrates, orexin A displays more variability, in particular due to an "insertion sequence" that is present in teleost fish, but not in skate and tetrapods. RT-PCR studies show that preproOX mRNA has a widespread distribution within the brain and is present in several peripheral tissues, including gastrointestinal tract, heart and testes. Fasting induced increases in preproOX expression in the hypothalamus, suggesting that orexin might play a role in the regulation of food intake in winter skate. Copyright © 2010 Elsevier Inc. All rights reserved.

  1. Habituation of 10-year-old hockey players to treadmill skating.

    Science.gov (United States)

    Lockwood, Kelly L; Frost, Gail

    2007-05-01

    This study assessed changes in selected physiological and kinematic variables over 6 weeks of treadmill skating in an effort to understand the process of habituation to this novel training modality. Seven male, Atom-A hockey players who were injury-free and had no previous treadmill skating experience participated in the study. Players performed four 1-min skating bouts at progressively increasing speeds, each week, for 6 weeks. One speed (10.5 km/h) was repeated weekly to allow for assessment of the habituation process. Our criteria for habituation were: a decrease in stride rate, heart rate and rating of perceived exertion, and an increase in stride length, trunk angle and vertical movement of the centre of mass, leading to a plateau, over the course of the 6-week study. Significant decreases were seen in stride rate, heart rate and ratings of perceived exertion, and significant increases were found in stride length. Some of these changes were evident after only one week of training and all were present by week 4. After 6 weeks (24 min) of exposure to treadmill skating, all participants displayed a visibly more efficient skating style.

  2. Speed and heart-rate profiles in skating and classical cross-country skiing competitions.

    Science.gov (United States)

    Bolger, Conor M; Kocbach, Jan; Hegge, Ann Magdalen; Sandbakk, Øyvind

    2015-10-01

    To compare the speed and heart-rate profiles during international skating and classical competitions in male and female world-class cross-country skiers. Four male and 5 female skiers performed individual time trials of 15 km (men) and 10 km (women) in the skating and classical techniques on 2 consecutive days. Races were performed on the same 5-km course. The course was mapped with GPS and a barometer to provide a valid course and elevation profile. Time, speed, and heart rate were determined for uphill, flat, and downhill terrains throughout the entire competition by wearing a GPS and a heart-rate monitor. Times in uphill, flat, and downhill terrain were ~55%, 15-20%, and 25-30%, respectively, of the total race time for both techniques and genders. The average speed differences between skating and classical skiing were 9% and 11% for men and women, respectively, and these values were 12% and 15% for uphill, 8% and 13% for flat (all P skating and classical, respectively, with corresponding numbers of 11% and 14% for uphill, 6% and 11% for flat, and 4% and 5% for downhill terrain (all P skating and classical techniques and between the 2 genders were found on uphill terrain. Therefore, these speed differences could not be explained by variations in exercise intensity.

  3. Neuromuscular Activation During Short-Track Speed Skating in Young Athletes.

    Science.gov (United States)

    Felser, Sabine; Behrens, Martin; Fischer, Susanne; Baeumler, Mario; Salomon, Ralf; Bruhn, Sven

    2016-10-01

    To investigate differences in muscle activation of both legs between the straight and the curve and changes in muscle activity during a 1000-m time trial (TT) and their relationship to the change in skating velocity in 9 young short-track speed skaters. The authors recorded skating times and EMG data from different leg muscles during maximum-effort skating trials on the straight and in the curve, as well as during a 1000-m TT. Muscle activation differs between the straight and the curves and between legs; ie, average activities of selected muscles of the right leg were significantly higher during skating through the curves than in the straights. This could not be observed for the left leg. The reduction in speed during the 1000-m TT highly correlates with the decrease in the muscle activity of both the tibialis anterior and the rectus femoris of the right leg. Muscle recruitment is different in relation to lap section (straight vs curve) and leg (right vs left leg). The decreased muscle activity of the tibialis anterior and rectus femoris of the right leg showed the highest relationships with the reduction in skating speed during the 1000-m TT.

  4. Ice Hockey Lung – A Case of Mass Nitrogen Dioxide Poisoning in The Czech Republic

    Directory of Open Access Journals (Sweden)

    Kristian Brat

    2013-01-01

    Full Text Available Nitrogen dioxide (NO2 is a toxic gas, a product of combustion in malfunctioning ice-resurfacing machines. NO2 poisoning is rare but potentially lethal. The authors report a case of mass NO2 poisoning involving 15 amateur ice hockey players in the Czech Republic. All players were treated in the Department of Respiratory Diseases at Brno University Hospital in November 2010 – three as inpatients because they developed pneumonitis. All patients were followed-up until November 2011. Complete recovery in all but one patient was achieved by December 2010. None of the 15 patients developed asthma-like disease or chronic cough. Corticosteroids appeared to be useful in treatment. Electric-powered ice-resurfacing machines are preferable in indoor ice skating arenas.

  5. Head-impact mechanisms in men's and women's collegiate ice hockey.

    Science.gov (United States)

    Wilcox, Bethany J; Machan, Jason T; Beckwith, Jonathan G; Greenwald, Richard M; Burmeister, Emily; Crisco, Joseph J

    2014-01-01

    Concussion injury rates in men's and women's ice hockey are reported to be among the highest of all collegiate sports. Quantification of the frequency of head impacts and the magnitude of head acceleration as a function of the different impact mechanisms (eg, head contact with the ice) that occur in ice hockey could provide a better understanding of this high injury rate. To quantify and compare the per-game frequency and magnitude of head impacts associated with various impact mechanisms in men's and women's collegiate ice hockey players. Cohort study. Collegiate ice hockey rink. Twenty-three men and 31 women from 2 National Collegiate Athletic Association Division I ice hockey teams. We analyzed magnitude and frequency (per game) of head impacts per player among impact mechanisms and between sexes using generalized mixed linear models and generalized estimating equations to account for repeated measures within players. Participants wore helmets instrumented with accelerometers to allow us to collect biomechanical measures of head impacts sustained during play. Video footage from 53 games was synchronized with the biomechanical data. Head impacts were classified into 8 categories: contact with another player; the ice, boards or glass, stick, puck, or goal; indirect contact; and contact from celebrating. For men and women, contact with another player was the most frequent impact mechanism, and contact with the ice generated the greatest-magnitude head accelerations. The men had higher per-game frequencies of head impacts from contact with another player and contact with the boards than did the women (P < .001), and these impacts were greater in peak rotational acceleration (P = .027). Identifying the impact mechanisms in collegiate ice hockey that result in frequent and high-magnitude head impacts will provide us with data that may improve our understanding of the high rate of concussion in the sport and inform injury-prevention strategies.

  6. Movement Characteristics and Heart Rate Profiles Displayed by Female University Ice Hockey Players

    Directory of Open Access Journals (Sweden)

    Joel Jackson

    2016-01-01

    Full Text Available Background: Women’s ice hockey is widely popular but the various movement patterns, heart rate responses and work to rest ratios during competitive games has not been adequately investigated.  Objectives: This study determined the frequency and duration of movements that female players perform in ice hockey games using time-motion analysis. The intensity of the game activities were also assessed by heart rate (HR responses and work to rest ratios (W:R. Methods: Twenty-two university female ice hockey players were filmed performing a number of movements during three regular season league games. Results: The following movement patterns were categorized in percent of time performed during the games: forward gliding on ice (36.3 ± 6.2%, forward skating at a moderate intensity (31.2 ± 6.2%, backward glide (9.5 ± 4.1%, standing (7.1 ± 5.9%, struggling (6.3 ± 2.6%, forward skating at maximal intensity (5.3 ± 3.3%, backwards skating at moderate intensity (3.1 ± 3.3%. Defense stood and glided backward more than forwards but skated less at a high or maximal intensity. Positional differences were also observed during different game play situations. The highest HR (±SD achieved during shifts was 182 ± 10 and HR averaged 174 ± 9 bpm for the whole duration of the shifts. The shift and game W:R ratios for all players were 1:1.6 and 1: 3.7, respectively. Conclusions: The findings of this study indicate that female ice hockey games are played at a low to moderate intensity most of the time (~84% of the time spent and are interspersed with brief, intermittent high intensity activities that vary according to player position and game play situation. It was also apparent that female players display markedly high HR responses during game-play indicative of a substantial cardiovascular demand in ice hockey. Keywords: game analysis, work to rest ratios, exercise intensity

  7. The effects of poling on physiological, kinematic and kinetic responses in roller ski skating.

    Science.gov (United States)

    Grasaas, Erik; Hegge, Ann Magdalen; Ettema, Gertjan; Sandbakk, Øyvind

    2014-09-01

    We investigated the effects of poling on physiological, kinematic and kinetic responses in the G4 skating technique where the poling movement is synchronized with the leg push-off on one side (strong side) followed by a forward arm swing during the leg push-off on the other side (weak side). G4 skating with (G4-P) and without (G4-NP) poling was compared in 17 elite male cross-country skiers during 4-min submaximal tests on a 2% inclined roller ski treadmill at 10, 15 and 20 km h(-1). G4-P demonstrated less ventilatory stress and higher gross efficiency compared to G4-NP at all velocities, and the blood lactate concentration was lower at the high velocity (all P skating technique. Thus, poling provides possibilities to increase total propulsion, to reduce ski forces and to enhance skiing efficiency.

  8. Inline skating for balance and strength promotion in children during physical education.

    Science.gov (United States)

    Muehlbauer, Thomas; Kuehnen, Matthias; Granacher, Urs

    2013-12-01

    Deficiencies in balance and strength are common in children and they may lead to injuries. This study investigated the effects of inline skating exercise on balance and strength performance in healthy children. Twenty 11-12-year-old children (8 girls, 12 boys) were assigned to an intervention (n = 10) or a control (n = 10) group. Participants in the intervention group underwent a 4-week inline skating program (2 times/week, 90 min. each) integrated in their physical education lessons. Balance and strength were measured using the Star Excursion Balance test and the countermovement jump test. As compared to the control group, the intervention group significantly improved balance (17-48%, Cohen's d = 0.00-1.49) and jump height (8%, Cohen's d = 0.48). In children, inline skating is a safe, feasible (90% adherence rate), and effective program that can be integrated in physical education lessons to promote balance and strength.

  9. From coexistence to competitive exclusion: can overfishing change the outcome of competition in skates (Chondrichthyes, Rajidae?

    Directory of Open Access Journals (Sweden)

    Natalia L Ruocco

    2012-03-01

    Full Text Available Competition for food could be a major force driving changes in the community structure of skates (Rajidae subjected to fishing exploitation. Under this hypothesis, small skates are released from competition with larger skates after fishing has depleted the larger species. Here, we compare the abundance patterns of two sympatric skates with similar niches but different life histories, Bathyraja albomaculata (larger and slow-reproducing and Bathyraja macloviana (smaller and faster-reproducing, before (1971, 1978 and after (1998-2004 a 108% increase in industrial bottom trawling on the southeastern South American shelf in order to test the prediction that B. macloviana should competitively exclude B. albomaculata after the increase in fishing mortality. In 1971 and 1978, there was no relationship between the abundance of both species, indicating that they coexisted over large scales. In 1998-2004, the relationship between the abundances of these skates was bell-shaped, indicating that both species increased in abundance at low densities until peaking, after which B. albomaculata decreased when B. macloviana became more abundant, consistent with resource competition. We tested whether food may be a potential limiting resource by comparing the diet of both species. The two species consumed mostly polychaetes, differing only in the consumption of polychaetes from the family Nephthyidae, which was much higher for B. macloviana. Bathyraja macloviana could replace B. albomaculata at high densities when food resources may become scarce. These results support the hypothesis that competition release is an important factor explaining the changes in skate communities in overexploited areas.

  10. Detection of weak electric fields by sharks, rays, and skates.

    Science.gov (United States)

    Adair, Robert K.; Astumian, R. Dean; Weaver, James C.

    1998-09-01

    The elasmobranchs-sharks, rays, and skates-can detect very weak electric fields in their aqueous environment through a complex sensory system, the ampullae of Lorenzini. The ampullae are conducting tubes that connect the surface of the animal to its interior. In the presence of an electric field, the potential of the surface of the animal will differ from that of the interior and that potential is applied across the apical membrane of the special sensory cells that line the ampullae. The firing rate of the afferent neurons that transmit signals from the ampullae has been shown to vary with that potential. We show that those firing rates can be described quantitatively in terms of synchronous firing of the sensory cells that feed the neurons. We demonstrate that such synchronism follows naturally from a hypothetical weak cell-to-cell interaction that results in a self-organization of the sensory cells. Moreover, the pulse rates of those cells-and the neurons that service the cells-can be expected to vary with the imposed electric fields in accord with measured values through actions of voltage gated transmembrane proteins in the apical sector of the cell membranes that admit Ca(++) ions. We also present a more conjectural model of signal processing at the neuron level that could exploit small differences in firing rates of nerve fibers servicing different ampullae to send an unambiguous signal to the central nervous system of the animal. (c) 1998 American Institute of Physics.

  11. Diet and scavenging habits of the smooth skate Dipturus innominatus.

    Science.gov (United States)

    Forman, J S; Dunn, M R

    2012-04-01

    The diet of smooth skate Dipturus innominatus was determined from examination of stomach contents of 321 specimens of 29·3-152·0 cm pelvic length, sampled from research and commercial trawlers at depths of 231-789 m on Chatham Rise, New Zealand. The diet was dominated by the benthic decapods Metanephrops challengeri and Munida gracilis, the natant decapod Campylonotus rathbunae and fishes from 17 families, of which hoki Macruronus novaezelandiae, sea perch Helicolenus barathri, various Macrouridae and a variety of discarded fishes were the most important. Multivariate analyses indicated the best predictors of diet variability were D. innominatus length and a spatial model. The diet of small D. innominatus was predominantly small crustaceans, with larger crustaceans, fishes and then scavenged discarded fishes increasing in importance as D. innominatus got larger. Scavenged discards were obvious as fish heads or tails only, or skeletal remains after filleting, often from pelagic species. Demersal fish prey were most frequent on the south and west Chatham Rise, in areas where commercial fishing was most active. Dipturus innominatus are highly vulnerable to overfishing, but discarding practices by commercial fishing vessels may provide a positive feedback to populations through improved scavenging opportunities. © 2012 NIWA. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  12. Skate, espacios urbanos y jóvenes en la ciudad de La Plata

    OpenAIRE

    Saraví, Jorge Ricardo

    2012-01-01

    El objetivo general que nos hemos planteado fue analizar la práctica del skate que llevan adelante los y las jóvenes en la ciudad. Por otro lado, nuestros objetivos específicos fueron: 1) relevar y describir acciones, características, particularidades, lugares, que asumen las diferentes prácticas del skate en la ciudad; 2) conocer las representaciones que acerca de esa práctica tienen los propios jóvenes y la sociedad; 3) profundizar en las implicancias sociales que tiene una práctica corpora...

  13. Arctic skate Amblyraja hyperborea preys on remarkably large glacial eelpouts Lycodes frigidus.

    Science.gov (United States)

    Byrkjedal, I; Christiansen, J S; Karamushko, O V; Langhelle, G; Lynghammar, A

    2015-01-01

    During scientific surveys on the continental slopes north-west of Spitsbergen and off north-east Greenland (c. 600 and 1000 m depths), two female Arctic skates Amblyraja hyperborea were caught while swallowing extraordinary large individuals of glacial eelpout Lycodes frigidus. The total length (LT) of the prey constituted 50 and 80% of the LT of the skates, which reveal that A. hyperborea are capable predators of fishes of surprisingly large relative size. © 2014 The Fisheries Society of the British Isles.

  14. Diet and feeding behaviour of longnosed skate Dipturus oxyrinchus.

    Science.gov (United States)

    Mulas, A; Bellodi, A; Cannas, R; Cau, Al; Cuccu, D; Marongiu, M F; Porcu, C; Follesa, M C

    2015-01-01

    A total of 255 longnosed skate Dipturus oxyrinchus caught in Sardinian waters (central-western Mediterranean Sea), was analysed with respect to fish total length (LT ), season and depth, in order to provide information on diet and feeding behaviour. Specimens ranging from 93 to 1153 mm LT , were collected at depths between 121 and 671 m, during experimental trawl surveys carried out from 2005 to 2010. The diet comprised crustaceans [prey specific index of relative importance (%IPSRI ) = 72·69], teleosts (%IPSRI  = 10·28) and molluscs (%IPSRI  = 10·94). Levins' index (Bi ) showed a narrow niche breadth (Bi  = 0·35). The mean ± s.e. trophic level (TL ) was 3·63 ± 0·50. The analysis showed major ontogenetic changes in the feeding behaviour. Early life stages were characterized by a benthic diet, which changed to benthopelagic during growth. Mysids, particularly Lophogaster typicus (%IPSRI  = 34·51), were the main prey items of immature individuals, replaced by euphausiids, mainly Meganyctiphanes norvegica (%IPSRI  = 13·19), in maturing fish. Crustaceans became less important in mature specimens, being replaced by molluscs (%IPSRI  = 28·99) and teleosts (%IPSRI  = 24·56). A concomitant increase of the TL was recorded (mean ± s.e. = 3·41 ± 0·44, 3·75 ± 0·54 and 4·28 ± 0·61 for immature, maturing and mature individuals). These feeding patterns ensured low levels of intraspecific competition. This study provides new information about the role that the D. oxyrinchus plays in the marine food chain and data now essential to formulate new and effective management plans for this species. © 2014 The Fisheries Society of the British Isles.

  15. Falling drops skating on a film of air

    Science.gov (United States)

    Rubinstein, Shmuel

    2012-02-01

    When a raindrop hits a window, the surface immediately becomes wet as the water spreads. Indeed, this common observation of a drop impacting a surface is ubiquitous in our everyday experience. I will show that the impact of a drop on a surface is a much richer, more complex phenomenon than our simple experience may suggests: To completely wet the surface the drop must first expel all the air beneath it; however, this does not happened instantaneously. Instead, a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the fluid spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate laterally outward at strikingly high velocities. Simultaneously, the wetting fluid spreads inward at a much slower velocity, trapping a bubble of air within the drop. However, these events occur at diminutive length scales and fleeting time scales; therefore, to visualize them we develop new imaging modalities that are sensitive to the behavior right at the surface and that have time resolution superior to even the very fastest cameras. These imaging techniques reveal that the ultimate wetting of the surface occurs through a completely new mechanism, the breakup of the thin film of air through a spinodal like dewetting process that breaks the cylindrical symmetry of the impact and drives an anomalously rapid spreading of a wetting front. These results are in accord with recent theoretical predictions and challenge the prevailing paradigm in which contact between the liquid and solid occurs immediately, and spreading is dominated by the dynamics of a single contact line.

  16. Optimal pacing strategy: From theoretical modeling to reality in 1500m speed skating

    NARCIS (Netherlands)

    Hettinga, F.J.; de Koning, J.J.; Schmidt, L.J.I.; Wind, N.A.C.; McIntosh, B.; Foster, C.

    2011-01-01

    Purpose: Athletes are trained to choose the pace which is perceived to be correct during a specific effort, such as the 1500-m speed skating competition. The purpose of the present study was to "override" self-paced (SP) performance by instructing athletes to execute a theoretically optimal pacing

  17. Optimal pacing strategy : from theoretical modelling to reality in 1500-m speed skating

    NARCIS (Netherlands)

    Hettinga, F. J.; De Koning, J. J.; Schmidt, L. J. I.; Wind, N. A. C.; MacIntosh, B. R.; Foster, C.

    Purpose Athletes are trained to choose the pace which is perceived to be correct during a specific effort, such as the 1500-m speed skating competition. The purpose of the present study was to "override" self-paced (SP) performance by instructing athletes to execute a theoretically optimal pacing

  18. Pacing Strategy, Muscle Fatigue and Technique in 1500m Speed Skating and Cycling Time-Trials

    NARCIS (Netherlands)

    Stoter, Inge K; MacIntosh, Brian R; Fletcher, Jared R; Pootz, Spencer; Zijdewind, Inge; Hettinga, Florentina J

    2016-01-01

    PURPOSE: To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500m speed skating and cycling time-trials, when a faster or slower start is instructed. METHODS: Nine speed skaters and nine cyclists, all competing at regional or national level, performed two 1500m

  19. Shark and skate egg-cases cast up on two South African beaches ...

    African Journals Online (AJOL)

    Collections of chondrichthyan egg-cases cast ashore at two sites along the South African coastline were identified and examined for cause of mortality. A total of 574 egg-cases collected from False Bay could be attributed to five species of scyliorhinid shark. two skates and the elephantfish or chimaera, while the 538 ...

  20. Population structure and historical demography of the thorny skate (Amblyraja radiata, Rajidae) in the North Atlantic

    NARCIS (Netherlands)

    Chevolot, M.; Wolfs, P.H.J.; Palsson, J.; Rijnsdorp, A.D.; Stam, W.T.; Olsen, J.L.

    2007-01-01

    Population genetic structure of the thorny skate (Amblyraja radiata) was surveyed in >300 individuals sampled from Newfoundland, Iceland, Norway, the Kattegat and the central North Sea. A 290-bp fragment of the mt cytochrome-b gene was first screened by SSCP. Sequences of SSCP haplotypes revealed

  1. Community annotation and bioinformatics workforce development in concert--Little Skate Genome Annotation Workshops and Jamborees.

    Science.gov (United States)

    Wang, Qinghua; Arighi, Cecilia N; King, Benjamin L; Polson, Shawn W; Vincent, James; Chen, Chuming; Huang, Hongzhan; Kingham, Brewster F; Page, Shallee T; Rendino, Marc Farnum; Thomas, William Kelley; Udwary, Daniel W; Wu, Cathy H

    2012-01-01

    Recent advances in high-throughput DNA sequencing technologies have equipped biologists with a powerful new set of tools for advancing research goals. The resulting flood of sequence data has made it critically important to train the next generation of scientists to handle the inherent bioinformatic challenges. The North East Bioinformatics Collaborative (NEBC) is undertaking the genome sequencing and annotation of the little skate (Leucoraja erinacea) to promote advancement of bioinformatics infrastructure in our region, with an emphasis on practical education to create a critical mass of informatically savvy life scientists. In support of the Little Skate Genome Project, the NEBC members have developed several annotation workshops and jamborees to provide training in genome sequencing, annotation and analysis. Acting as a nexus for both curation activities and dissemination of project data, a project web portal, SkateBase (http://skatebase.org) has been developed. As a case study to illustrate effective coupling of community annotation with workforce development, we report the results of the Mitochondrial Genome Annotation Jamborees organized to annotate the first completely assembled element of the Little Skate Genome Project, as a culminating experience for participants from our three prior annotation workshops. We are applying the physical/virtual infrastructure and lessons learned from these activities to enhance and streamline the genome annotation workflow, as we look toward our continuing efforts for larger-scale functional and structural community annotation of the L. erinacea genome.

  2. Community annotation and bioinformatics workforce development in concert—Little Skate Genome Annotation Workshops and Jamborees

    Science.gov (United States)

    Wang, Qinghua; Arighi, Cecilia N.; King, Benjamin L.; Polson, Shawn W.; Vincent, James; Chen, Chuming; Huang, Hongzhan; Kingham, Brewster F.; Page, Shallee T.; Farnum Rendino, Marc; Thomas, William Kelley; Udwary, Daniel W.; Wu, Cathy H.

    2012-01-01

    Recent advances in high-throughput DNA sequencing technologies have equipped biologists with a powerful new set of tools for advancing research goals. The resulting flood of sequence data has made it critically important to train the next generation of scientists to handle the inherent bioinformatic challenges. The North East Bioinformatics Collaborative (NEBC) is undertaking the genome sequencing and annotation of the little skate (Leucoraja erinacea) to promote advancement of bioinformatics infrastructure in our region, with an emphasis on practical education to create a critical mass of informatically savvy life scientists. In support of the Little Skate Genome Project, the NEBC members have developed several annotation workshops and jamborees to provide training in genome sequencing, annotation and analysis. Acting as a nexus for both curation activities and dissemination of project data, a project web portal, SkateBase (http://skatebase.org) has been developed. As a case study to illustrate effective coupling of community annotation with workforce development, we report the results of the Mitochondrial Genome Annotation Jamborees organized to annotate the first completely assembled element of the Little Skate Genome Project, as a culminating experience for participants from our three prior annotation workshops. We are applying the physical/virtual infrastructure and lessons learned from these activities to enhance and streamline the genome annotation workflow, as we look toward our continuing efforts for larger-scale functional and structural community annotation of the L. erinacea genome. PMID:22434832

  3. Complete Genome Sequence of a Rhodococcus Species Isolated from the Winter Skate Leucoraja ocellata.

    Science.gov (United States)

    Wiens, Julia; Ho, Ryan; Fernando, Dinesh; Kumar, Ayush; Loewen, Peter C; Brassinga, Ann Karen C; Anderson, W Gary

    2016-09-01

    We report here a genome sequence for Rhodococcus sp. isolate UM008 isolated from the renal/interrenal tissue of the winter skate Leucoraja ocellata Genome sequence analysis suggests that Rhodococcus bacteria may act in a novel mutualistic relationship with their elasmobranch host, serving as biocatalysts in the steroidogenic pathway of 1α-hydroxycorticosterone. Copyright © 2016 Wiens et al.

  4. Population structure and historical demography of the thorny skate (Amblyraja radiata, Rajidae) in the North Atlantic

    NARCIS (Netherlands)

    Chevolot, Malia; Wolfs, Peter H. J.; Palsson, Jonbjorn; Rijnsdorp, Adriaan D.; Stam, Wytze T.; Olsen, Jeanine L.; Palson, J.

    Population genetic structure of the thorny skate (Amblyraja radiata) was surveyed in > 300 individuals sampled from Newfoundland, Iceland, Norway, the Kattegat and the central North Sea. A 290-bp fragment of the mt cytochrome-b gene was first screened by SSCP. Sequences of SSCP haplotypes revealed

  5. Comparison of split double and triple twists in pair figure skating.

    Science.gov (United States)

    King, Deborah L; Smith, Sarah L; Brown, Michele R; McCrory, Jean L; Munkasy, Barry A; Scheirman, Gary I

    2008-05-01

    In this study, we compared the kinematic variables of the split triple twist with those of the split double twist to help coaches and scientists understand these landmark pair skating skills. High-speed video was taken during the pair short and free programmes at the 2002 Salt Lake City Winter Olympics and the 2003 International Skating Union Grand Prix Finals. Three-dimensional analyses of 14 split double twists and 15 split triple twists from eleven pairs were completed. In spite of considerable variability in the performance variables among the pairs, the main difference between the split double twists and split triple twists was an increase in rotational rate. While eight of the eleven pairs relied primarily on an increased rotational rate to complete the split triple twist, three pairs employed a combined strategy of increased rotational rate and increased flight time due predominantly to delayed or lower catches. These results were similar to observations of jumps in singles skating for which the extra rotation is typically due to an increase in rotational velocity; increases in flight time come primarily from delayed landings as opposed to additional height during flight. Combining an increase in flight time and rotational rate may be a good strategy for completing the split triple twist in pair skating.

  6. Pacing Behavior and Tactical Positioning in 500-and 1000-m Short-Track Speed Skating

    NARCIS (Netherlands)

    Noorbergen, Olaf S.; Konings, Marco J.; Micklewright, Dominic; Elferink-Gemser, Marge T.; Hettinga, Florentina J.

    Purpose: To explore pacing behavior and tactical positioning during the shorter 500- and 1000-m short-track competitions. Methods: Lap times and intermediate rankings of elite 500- and 1000-m short-track-skating competitors were collected over the 2012-13 season. First, lap times were analyzed using

  7. The Vibe of Skating : Design and Testing of a Vibro-Tactile Feedback System

    NARCIS (Netherlands)

    Jansen, A.J.; Dekker, M.C.; van der Steen, Diederik; Espinosa, Hugo G.; Rowlands, David R.; Shepherd, Jonathan; Thiel, David V.

    2018-01-01

    Providing athletes with real-time feedback on their performance is becoming common in many sports, also in speed skating. This research-by-design project aims at finding a tool that allows the speed skater to get real-time feedback on his performance. Speed skaters often mention a so-called “good

  8. Validation of the Sensewear Armband during recreational in-line skating.

    Science.gov (United States)

    Soric, Maroje; Mikulic, Pavle; Misigoj-Durakovic, Marjeta; Ruzic, Lana; Markovic, Goran

    2012-03-01

    Multi-sensor body monitors that combine accelerometry with other physiological data are designed to overcome drawbacks of accelerometers in assessing activities with little or no vertical movement. One of such devices is the Sensewear Armband (SWA) which has been extensively validated during various activities. However, very few of the validation studies included activities other than walking and running. The aim of this investigation was to assess the validity of the SWA during recreational in-line skating. Nineteen participants (11 females and 8 males), 28 (±6) years of age, performed in-line skating exercise on a circular track at a self-selected pace. Energy expenditure was measured with the SWA and the Cosmed K4b(2) breath-by-breath portable metabolic unit. The mean (SD) energy expenditure during in-line skating estimated by the SWA [25.5 (5.8) kJ/min] was significantly lower compared with indirect calorimetry [44.2 (9.7) kJ/min, P skating by as much as 24-56% compared with indirect calorimetry. In conclusion, the results of the present study indicate that the SWA is not able to overcome the drawbacks of accelerometry in assessing activities with limited vertical movement.

  9. 76 FR 53872 - Fisheries of the Northeastern United States; Northeast Skate Complex Fishery; Secretarial...

    Science.gov (United States)

    2011-08-30

    ... scientific information indicating significant increases in skate biomass. DATES: Public comments must be... may submit comments, identified by NOAA-NMFS-2011-0197, by any one of the following methods... from the resulting list and click on the ``Submit a Comment'' icon on the right of that line. Fax: (978...

  10. Bacterial succession during curing process of a skate (Dipturus batis) and isolation of novel strains.

    Science.gov (United States)

    Reynisson, E; Thornór Marteinsson, V; Jónsdóttir, R; Magnússon, S H; Hreggvidsson, G O

    2012-08-01

    To study the succession of cultivated and uncultivated microbes during the traditional curing process of skate. The microbial diversity was evaluated by sequencing 16Sr RNA clone libraries and cultivation in variety of media from skate samples taken periodically during a 9-day curing process. A pH shift was observed (pH 6·64-9·27) with increasing trimethylamine (2·6 up to 75·6 mg N per 100 g) and total volatile nitrogen (TVN) (from 58·5 to 705·8 mg N per 100 g) but with relatively slow bacterial growth. Uncured skate was dominated by Oceanisphaera and Pseudoalteromonas genera but was substituted after curing by Photobacterium and Aliivibrio in the flesh and Pseudomonas on the skin. Almost 50% of the clone library is derived from putative undiscovered species. Cultivation and enrichment strategies resulted in isolation of putatively new species belonging to the genera Idiomarina, Rheinheimera, Oceanisphaera, Providencia and Pseudomonas. The most abundant genera able to hydrolyse urea to ammonia were Oceanisphaera, Psychrobacter, Pseudoalteromonas and isolates within the Pseudomonas genus. The curing process of skate is controlled and achieved by a dynamic bacterial community where the key players belong to Oceanisphaera, Pseudoalteromonas, Photobacterium, Aliivibrio and Pseudomonas. For the first time, the bacterial population developments in the curing process of skate are presented and demonstrate a reservoir of many yet undiscovered bacterial species. No Claim to Norwegian Government works Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  11. Hepatic uptake and biliary excretion of manganese in the little skate, Leucoraja erinacea.

    Science.gov (United States)

    Madejczyk, Michael S; Boyer, James L; Ballatori, Nazzareno

    2009-05-01

    The liver is a major organ involved in regulating whole body manganese (Mn) homeostasis; however, the mechanisms of Mn transport across the hepatocyte basolateral and canalicular membranes remain poorly defined. To gain insight into these transport steps, the present study measured hepatic uptake and biliary excretion of Mn in an evolutionarily primitive marine vertebrate, the elasmobranch Leucoraja erinacea, the little skate. Mn was rapidly removed from the recirculating perfusate of isolated perfused skate livers in a dose-dependent fashion; however, only a small fraction was released into bile (skate hepatocytes in culture. Mn uptake was inhibited by a variety of divalent metals, but not by cesium. Analysis of the concentration-dependence of Mn uptake revealed of two components, with apparent K(m) values 1.1+/-0.1 microM and 112+/-29 microM. The K(m) value for the high-affinity component was similar to the measured skate blood Mn concentration, 1.9+/-0.5 microM. Mn uptake was reduced by nearly half when bicarbonate was removed from the culture medium, but was unaffected by a change in pH from 6.5 to 8.5, or by substitution of Na with Li or K. Mn efflux from the hepatocytes was also rapid, and was inhibited when cells were treated with 0.5 mM 2,4-dinitrophenol to deplete ATP levels. These data indicate that skate liver has efficient mechanisms for removing Mn from the sinusoidal circulation, whereas overall biliary excretion is low and appears to be mediated in part by an ATP-sensitive mechanism.

  12. The influence of increased distal loading on metabolic cost, efficiency, and kinematics of roller ski skating.

    Science.gov (United States)

    Bolger, Conor M; Bessone, Veronica; Federolf, Peter; Ettema, Gertjan; Sandbakk, Øyvind

    2018-01-01

    The purpose of the present study was to examine the influence of increased loading of the roller ski on metabolic cost, gross efficiency, and kinematics of roller ski skating in steep and moderate terrain, while employing two incline-specific techniques. Ten nationally ranked male cross-country skiers were subjected to four 7-minute submaximal intervals, with 0, 0.5, 1.0, and 1.5 kg added beneath the roller-ski in a randomized order. This was done on two separate days, with the G2 skating at 12% incline and 7 km/h speed and G3 skating at 5% incline and 14 km/h speed, respectively. At 12% incline, there was a significant increase in metabolic rate and a decrease in gross efficiency with added weight (P0.05). No changes in cycle characteristics were observed between the different ski loadings at either incline, although the lateral and vertical displacements of the foot/skis were slightly altered at 12% incline with added weight. In conclusion, the present study demonstrates that increased loading of the ski increases the metabolic cost and reduces gross efficiency during steep uphill roller skiing in G2 skating, whereas no significant effect was revealed when skating on relatively flat terrain in G3. Cycle characteristics remained unchanged across conditions at both inclines, whereas small adjustments in the displacement of the foot coincided with the efficiency changes in uphill terrain. The increased RPE values with added ski-weight at both inclines indicates that other factors than those measured here could have influenced effort and/or fatigue when lifting a heavier ski.

  13. AFSC/REFM: Movement of Alaska skates (Bathyraja parmifera) in the Bering Sea , determined through conventional tagging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains the results of a tagging study being conducted on the Alaska skate (Bathyraja parmifera) in the eastern Bering Sea. The purpose of the study is...

  14. Calcium activated K⁺ channels in the electroreceptor of the skate confirmed by cloning. Details of subunits and splicing.

    Science.gov (United States)

    King, Benjamin L; Shi, Ling Fang; Kao, Peter; Clusin, William T

    2016-03-01

    Elasmobranchs detect small potentials using excitable cells of the ampulla of Lorenzini which have calcium-activated K(+) channels, first described in 1974. A distinctive feature of the outward current in voltage clamped ampullae is its apparent insensitivity to voltage. The sequence of a BK channel α isoform expressed in the ampulla of the skate was characterized. A signal peptide is present at the beginning of the gene. When compared to human isoform 1 (the canonical sequence), the largest difference was absence of a 59 amino acid region from the S8-S9 intra-cellular linker that contains the strex regulatory domain. The ampulla isoform was also compared with the isoform predicted in late skate embryos where strex was also absent. The BK voltage sensors were conserved in both skate isoforms. Differences between the skate and human BK channel included alternative splicing. Alternative splicing occurs at seven previously defined sites that are characteristic for BK channels in general and hair cells in particular. Skate BK sequences were highly similar to the Australian ghost shark and several other vertebrate species. Based on alignment of known BK sequences with the skate genome and transcriptome, there are at least two isoforms of Kcnma1α expressed in the skate. One of the β subunits (β4), which is known to decrease voltage sensitivity, was also identified in the skate genome and transcriptome and in the ampulla. These studies advance our knowledge of BK channels and suggest further studies in the ampulla and other excitable tissues. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Calcium Activated K+ Channels in The Electroreceptor of the Skate Confirmed by Cloning. Details of Subunits and Splicing

    Science.gov (United States)

    King, Benjamin L.; Shi, Ling Fang; Kao, Peter; Clusin, William T.

    2015-01-01

    Elasmobranchs detect small potentials using excitable cells of the ampulla of Lorenzini which have calcium-activated K+ channels, first described in l974. A distinctive feature of the outward current in voltage clamped ampullae is its apparent insensitivity to voltage. The sequence of a BK channel α isoform expressed in the ampulla of the skate was characterized. A signal peptide is present at the beginning of the gene. When compared to human isoform 1 (the canonical sequence), the largest difference was absence of a 59 amino acid region from the S8-S9 intracellular linker that contains the strex regulatory domain. The ampulla isoform was also compared with the isoform predicted˜ in late skate embryos where strex was also absent. The BK voltage sensors were conserved in both skate isoforms. Differences between the skate and human BK channel included alternative splicing. Alternative splicing occurs at seven previously defined sites that are characteristic for BK channels in general and hair cells in particular. Skate BK sequences were highly similar to the Australian ghost shark and several other vertebrate species. Based on alignment of known BK sequences with the skate genome and transcriptome, there are at least two isoforms of Kcnma1α expressed in the skate. One of the β subunits (β4), which is known to decrease voltage sensitivity, was also identified in the skate genome and transcriptome and in the ampulla. These studies advance our knowledge of BK channels and suggest further studies in the ampulla and other excitable tissues. PMID:26687710

  16. Ice Ages

    Indian Academy of Sciences (India)

    that the precession of the earth's orbit caused ice ages. The precession of the earth's orbit leads to changes in the time of the year at which ... than in the southern hemisphere. ..... small increase in ocean temperature implies a large increase in.

  17. Investigation of Positional Differences in Fitness of Male University Ice Hockey Players and the Frequency, Time Spent and Heart Rate of Movement Patterns during Competition

    Directory of Open Access Journals (Sweden)

    Joel Jackson

    2017-07-01

    Full Text Available Background:  Men’s university ice hockey has received little scientific attention over the past 30 years, a time in which the traits of the players and the demands of the game have evolved.  Objectives: This study compared the physiological characteristics of university ice hockey players and examined the frequency and duration of the different movement patterns and heart rate (HR responses during competition. Methods: Twenty male ice hockey players from the same team ( age ± SD = 22±2 years underwent a fitness evaluation and were filmed and HR monitored during regular season games. Results: Forwards and defense had similar fitness and only differed on % fatigue index and peak heart during on-ice sprinting (P<0.05. Defense stood, glided and skated backwards more than forwards and forwards skated at a moderate intensity and glided forward more than defense (P<0.05. All players spent the majority of game time gliding forward (60% of the time followed by skating forward at a moderate intensity (17% and standing with little movement (9%. Average HR during the game reached 96 and 92 % and peak HR was 100 and 96 % of maximum in forwards and defense, respectively. Conclusions: Male university hockey players present with a high level of physical fitness in a variety of categories with few differences between forwards and defense. Movement patterns during games suggest that players are performing low to moderate intensity on-ice activities the majority of the time. Paradoxically, HR continues to climb to near maximum during on ice shifts.

  18. Biomechanical comparison of the double-push technique and the conventional skate skiing technique in cross-country sprint skiing.

    Science.gov (United States)

    Stöggl, Thomas; Müller, Erich; Lindinger, Stefan

    2008-09-01

    The aims of the study were to: (1) adapt the "double-push" technique from inline skating to cross-country skiing; (2) compare this new skiing technique with the conventional skate skiing cross-country technique; and (3) test the hypothesis that the double-push technique improves skiing speed in a short sprint. 13 elite skiers performed maximum-speed sprints over 100 m using the double-push skate skiing technique and using the conventional "V2" skate skiing technique. Pole and plantar forces, knee angle, cycle characteristics, and electromyography of nine lower body muscles were analysed. We found that the double-push technique could be successfully transferred to cross-country skiing, and that this new technique is faster than the conventional skate skiing technique. The double-push technique was 2.9 +/- 2.2% faster (P push technique had a longer cycle length and a lower cycle rate, and it was characterized by higher muscle activity, higher knee extension amplitudes and velocities, and higher peak foot forces, especially in the first phase of the push-off. Also, the foot was more loaded laterally in the double-push technique than in the conventional skate skiing technique.

  19. Effects of Climate Change on Outdoor Skating in the Bei Hai Park of Beijing and Related Adaptive Strategies

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2017-06-01

    Full Text Available This paper reports findings derived from a study of the impacts of climate change on winter outdoor skating activities in the Chinese park of Bei Hai from 1989 to 2015. Based on field observation data and in-depth interviews, it was concluded that the outdoor skating activities, with a history of more than 1000 years, are being threatened by the warming climate. The opening dates and duration times of skating over the last 26 years showed periodic variations over three-year cycles. Increases of temperatures by 1 °C in December were associated with a 3.80-day delay in the skating-field opening dates and a 4.49-day decrease in the operation duration times. In particular, climate change has resulted in a loss of the skating field area and a reduction in the operation duration times, and tourists are moving north for skating-related recreation or conducting alternative activities. The current adaptive strategies are not very effective.

  20. cDNA cloning and characterization of Type I procollagen alpha1 chain in the skate Raja kenojei.

    Science.gov (United States)

    Hwang, Jae-Ho; Yokoyama, Yoshihiro; Mizuta, Shoshi; Yoshinaka, Reiji

    2006-05-01

    A full-length cDNA of the Type I procollagen alpha1 [pro-alpha1(I)] chain (4388 bp), coding for 1463 amino acid residues in the total length, was determined by RACE PCR using a cDNA library constructed from 4-week embryo of the skate Raja kenojei. The helical region of the skate pro-alpha1(I) chain consisted of 1014 amino acid residues - the same as other fibrillar collagen alpha chains from higher vertebrates. Comparison on denaturation temperatures of Type I collagens from the skate, rainbow trout (Oncorhynchus mykiss) and rat (Rattus norvegicus) revealed that the number of Gly-Pro-Pro and Gly-Gly in the alpha1(I) chains could be directly related to the thermal stability of the helix. The expression property of the skate pro-alpha1(I) chain mRNA and phylogenetic analysis with other vertebrate pro-alpha1(I) chains suggested that skate pro-alpha1(I) chain could be a precursor form of the skate Type I collagen alpha1 chain. The present study is the first evidence for the primary structure of full-length pro-alpha1(I) chain in an elasmobranch.

  1. The physiological and biomechanical differences between double poling and G3 skating in world class cross-country skiers.

    Science.gov (United States)

    Sandbakk, Øyvind; Leirdal, Stig; Ettema, Gertjan

    2015-03-01

    The current study compared differences in cycle characteristics, energy expenditure and peak speed between double poling (DP) and G3 skating. Eight world class male sprint skiers performed a 5-min submaximal test at 16 km h(-1) and an incremental test to exhaustion at a 5% incline during treadmill roller skiing with two different techniques: DP where all propulsion comes from poling, and G3 skating where leg skating is added to each double poling movement. Video analyses determined cycle characteristics; respiratory parameters and blood lactate concentration determined the physiological responses. G3 skating resulted in 16% longer cycle lengths at 16% lower cycle rates, whereas oxygen uptake was independent of technique during submaximal roller skiing. The corresponding advantages for G3 skating during maximal roller skiing were reflected in 14% higher speed, 30% longer cycle length at 16% lower cycle rate and 11% higher peak oxygen uptake (all p skating. This was done by major increases in cycle lengths at slightly lower cycle rates and a higher aerobic energy delivery. However, the oxygen uptake for a given submaximal speed was not affected by technique although higher cycle rate was used in DP.

  2. A simple video-based timing system for on-ice team testing in ice hockey: a technical report.

    Science.gov (United States)

    Larson, David P; Noonan, Benjamin C

    2014-09-01

    The purpose of this study was to describe and evaluate a newly developed on-ice timing system for team evaluation in the sport of ice hockey. We hypothesized that this new, simple, inexpensive, timing system would prove to be highly accurate and reliable. Six adult subjects (age 30.4 ± 6.2 years) performed on ice tests of acceleration and conditioning. The performance times of the subjects were recorded using a handheld stopwatch, photocell, and high-speed (240 frames per second) video. These results were then compared to allow for accuracy calculations of the stopwatch and video as compared with filtered photocell timing that was used as the "gold standard." Accuracy was evaluated using maximal differences, typical error/coefficient of variation (CV), and intraclass correlation coefficients (ICCs) between the timing methods. The reliability of the video method was evaluated using the same variables in a test-retest analysis both within and between evaluators. The video timing method proved to be both highly accurate (ICC: 0.96-0.99 and CV: 0.1-0.6% as compared with the photocell method) and reliable (ICC and CV within and between evaluators: 0.99 and 0.08%, respectively). This video-based timing method provides a very rapid means of collecting a high volume of very accurate and reliable on-ice measures of skating speed and conditioning, and can easily be adapted to other testing surfaces and parameters.

  3. Eulerian Method for Ice Crystal Icing

    NARCIS (Netherlands)

    Norde, Ellen; van der Weide, Edwin Theodorus Antonius; Hoeijmakers, Hendrik Willem Marie

    In this study, an ice accretion method aimed at ice crystal icing in turbofan engines is developed and demonstrated for glaciated as well as mixed-phase icing conditions. The particle trajectories are computed by an Eulerian trajectory method. The effects of heat transfer and phase change on the

  4. Sea ice - Multiyear cycles and white ice

    Science.gov (United States)

    Ledley, T. S.

    1985-01-01

    The multiyear thickness cycles represent one of the interesting features of the sea ice studies performed by Semtner (1976) and Washington et al. (1976) with simple thermodynamic models of sea ice. In the present article, a description is given of results which show that the insulating effect of snow on the surface of the sea ice is important in producing these multiyear cycles given the physics included in the model. However, when the formation of white ice is included, the cycles almost disappear. White ice is the ice which forms at the snow-ice interface when the snow layer becomes thick enough to depress the ice below the water level. Water infiltrates the snow by coming through the ice at leads and generally freezes there, forming white ice.

  5. Purification, structural characterization, and myotropic activity of a peptide related to des-Arg(9)-bradykinin from an elasmobranch fish, the little skate, Leucoraja erinacea.

    Science.gov (United States)

    Anderson, W Gary; Leprince, Jérôme; Conlon, J Michael

    2008-08-01

    A bradykinin (BK)-related peptide was isolated from heat-denaturated plasma from an elasmobranch fish, the little skate, Leucoraja erinacea after incubation with porcine pancreatic kallikrein. The primary structure of the peptide (H-Gly-Ile-Thr-Ser-Trp-Leu-Pro-Phe-OH; skate BK) shows limited structural similarity to the mammalian B1 receptor agonist, des-Arg(9)-BK. The myotropic activities of synthetic skate BK, and the analog skate [Arg(9)]BK, were examined in isolated skate vascular and intestinal smooth muscle preparations. Skate BK produced a concentration-dependent constriction of the mesenteric artery (EC(50)=4.37x10(-8)M; maximum response=103.4+/-10.23% of the response to 60mM KCl) but the response to skate [Arg(9)]BK was appreciably weaker (response to 10(-6)M=73.0+/-23.4% of the response to 60mM KCl). Neither the first branchial gill arch nor the ventral aorta responded to either purified peptide. Skate BK also produced a concentration-dependent constriction of intestinal smooth muscle preparations (EC(50)=2.74x10(-7)M; maximum response 31.0+/-12.2% of the response to 10(-5)M acetylcholine). Skate [Arg(9)]BK was without effect on the intestinal preparation. The data provide evidence for the existence of the kallikrein-kinin system in a phylogenetically ancient vertebrate group and the greater potency of skate BK compared with the analog skate [Arg(9)]BK suggests that the receptor mediating vascular responses resembles the mammalian B1 receptor more closely than the B2 receptor.

  6. The complete validated mitochondrial genome of the yellownose skate Zearaja chilensis (Guichenot 1848) (Rajiformes, Rajidae).

    Science.gov (United States)

    Vargas-Caro, Carolina; Bustamante, Carlos; Bennett, Michael B; Ovenden, Jennifer R

    2016-01-01

    The yellownose skate Zearaja chilensis is endemic to South America. The species is the target of a valuable commercial fishery in Chile, but is highly susceptible to over-exploitation. The complete mitochondrial genome was described from 694,593 sequences obtained using Ion Torrent Next Generation Sequencing. The total length of the mitogenome was 16,909 bp, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Comparison between the proposed mitogenome and one previously described from "raw fish fillets from a skate speciality restaurant in Seoul, Korea" resulted in 97.4% similarity, rather than approaching 100% similarity as might be expected. The 2.6% dissimilarity may indicate the presence of two separate stocks or two different species of, ostensibly, Z. chilensis in South America and highlights the need for caution when using genetic resources without a taxonomic reference or a voucher specimen.

  7. An Improved method for separation of leucocytes from peripheral blood of the little skate (Leucoraja erinacea)

    Science.gov (United States)

    Tomana, Mitsuru; Parton, Angela; Barnes, David W.

    2008-01-01

    Cartilaginous fish, especially sharks, rays and skates (elasmobranchs) hold interest as comparative models in immunology because they are thought to be among the organisms most closely related to the ancestor animal that first developed acquired immunity. The aim of this study was to improve methods used for the purification of viable leucocytes from peripheral blood of elasmobranchs. Here we describe modifications of density gradient centrifugation and medium formulation that improve isolation and analysis of highly-purified leucocytes from peripheral blood of a model elasmobranch, Leucoraja erinacea, the little skate. These techniques contribute to the preparation of elasmobranch immune cells that can be reliably analyzed by a variety of means, including the study of immune function. PMID:18474431

  8. Forecasting Turbine Icing Events

    DEFF Research Database (Denmark)

    Davis, Neil; Hahmann, Andrea N.; Clausen, Niels-Erik

    2012-01-01

    In this study, we present a method for forecasting icing events. The method is validated at two European wind farms in with known icing events. The icing model used was developed using current ice accretion methods, and newly developed ablation algorithms. The model is driven by inputs from the WRF...... mesoscale model, allowing for both climatological estimates of icing and short term icing forecasts. The current model was able to detect periods of icing reasonably well at the warmer site. However at the cold climate site, the model was not able to remove ice quickly enough leading to large ice...

  9. The complete mitochondrial genome of the endangered spotback skate, Atlantoraja castelnaui.

    Science.gov (United States)

    Duckett, Drew J L; Naylor, Gavin J P

    2016-05-01

    Chondrichthyes are a highly threatened class of organisms, largely due to overfishing and other human activities. The present study describes the complete mitochondrial genome (16,750 bp) of the endangered spotback skate, Atlantoraja castelnaui. The mitogenome is arranged in a typical vertebrate fashion, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 control region.

  10. Ground reaction forces produced by two different hockey skating arm swing techniques.

    Science.gov (United States)

    Hayward-Ellis, Julie; Alexander, Marion J L; Glazebrook, Cheryl M; Leiter, Jeff

    2017-10-01

    The arm swing in hockey skating can have a positive effect on the forces produced by each skate, and the resulting velocity from each push off. The main purpose of this study was to measure the differences in ground reaction forces (GRFs) produced from an anteroposterior versus a mediolateral style hockey skating arm swing. Twenty-four elite-level female hockey players performed each technique while standing on a ground-mounted force platform, and all trials were filmed using two video cameras. Force data was assessed for peak scaled GRFs in the frontal and sagittal planes, and resultant GRF magnitude and direction. Upper limb kinematics were assessed from the video using Dartfish video analysis software, confirming that the subjects successfully performed two distinct arm swing techniques. The mediolateral arm swing used a mean of 18.38° of glenohumeral flexion/extension and 183.68° of glenohumeral abduction/adduction while the anteroposterior technique used 214.17° and 28.97° respectively. The results of this study confirmed that the mediolateral arm swing produced 37% greater frontal plane and 33% less sagittal plane GRFs than the anteroposterior arm swing. The magnitudes of the resultant GRFs were not significantly different between the two techniques; however, the mediolateral technique produced a resultant GRF with a significantly larger angle from the direction of travel (44.44°) as compared to the anteroposterior technique (31.60°). The results of this study suggest that the direction of GRFs produced by the mediolateral arm swing more closely mimic the direction of lower limb propulsion during the skating stride.

  11. Reproductive characteristics and population decline of four species of skate (Rajidae) off the eastern coast of Canada.

    Science.gov (United States)

    Mcphie, R P; Campana, S E

    2009-07-01

    Four of the most common species of skate (Rajidae) were studied off eastern Canada to determine if their reproductive characteristics were linked to their population trajectories. The fecundity of the winter skate Leucoraja ocellata, the little skate Leucoraja erinacea, the thorny skate Amblyraja radiata and the smooth skate Malacoraja senta averaged between 41 and 56 egg cases per year for each species. For all species but L. ocellata, males matured at larger sizes and at later ages than females. Theoretical rates of population increase for non-equilibrium populations of L. ocellata (c. 0.07), M. senta (c. 0.14) and L. erinacea and A. radiata (c. 0.20) were low compared to most fishes, indicating that north-west Atlantic skates are intrinsically unproductive, yet are theoretically capable of supporting low-level fisheries. Nevertheless, the results of 36 years of research surveys indicate that the abundance of mature L. ocellata, A. radiata and M. senta all decreased by >90% since 1970, indicating that past fishing mortality (both directed and undirected) has outstripped the net productivity of the skate populations on the eastern Scotian Shelf. The relationship between maximum age (t(max)) and age of maturity (t(mat)) was a better predictor of population growth rate than was body size, with the species exhibiting the highest ratios of t(mat) :t(max) (L. ocellata = 0.68, M. senta = 0.66) having the lowest predicted population growth rates. L. ocellata appears to have the lowest productivity and has experienced the greatest population decline, thus raising concerns over its future status.

  12. Skate blade neck lacerations: a survey and case follow-up.

    Science.gov (United States)

    Stuart, Michael J; Link, Andrew A; Smith, Aynsley M; Krause, David A; Sorenson, Matthew C; Larson, Dirk R

    2009-11-01

    To learn about neck lacerations caused by skate blades in hockey. A retrospective Web-based survey and follow-up of registered USA Hockey players. Three hundred twenty-eight thousand eight hundred twenty-one of 457 038 registered USA Hockey players with a current e-mail address were contacted and invited to participate in the survey. Of 26 589 players (5.8% of all USA registered players) who responded to the survey, 247 were excluded due to incomplete data. Of 26 342 surveys analyzed, 23 199 respondents were men (88%), 3015 women (11.4%), and 128 (0.5%) did not designate gender. An original survey instrument was developed, formatted, and linked to a Mayo Clinic Web site. Neck lacerations from a skate blade, including mechanism, severity, treatment required, and the type of neck protector worn. Of the 26 342 respondents, 11 935 (45.4%) currently wear neck protection and 485 (1.8%) have sustained a neck laceration. When the laceration occurred, 132 of the players (27%) were wearing neck protection. Interviews with 33 injured players established that lacerations were superficial: 20 (61%) required bandaging only, 11 were sutured, and 2 were glued. Based on this survey, the currently available neck laceration protectors do not eliminate the risk of a neck laceration from a skate blade.

  13. Seamount egg-laying grounds of the deep-water skate Bathyraja richardsoni.

    Science.gov (United States)

    Henry, L-A; Stehmann, M F W; De Clippele, L; Findlay, H S; Golding, N; Roberts, J M

    2016-08-01

    Highly localized concentrations of elasmobranch egg capsules of the deep-water skate Bathyraja richardsoni were discovered during the first remotely operated vehicle (ROV) survey of the Hebrides Terrace Seamount in the Rockall Trough, north-east Atlantic Ocean. Conductivity-temperature-depth profiling indicated that the eggs were bathed in a specific environmental niche of well-oxygenated waters between 4·20 and 4·55° C, and salinity 34·95-35·06, on a coarse to fine-grained sandy seabed on the seamount's eastern flank, whereas a second type of egg capsule (possibly belonging to the skate Dipturus sp.) was recorded exclusively amongst the reef-building stony coral Solenosmilia variabilis. The depths of both egg-laying habitats (1489-1580 m) provide a de facto refuge from fisheries mortality for younger life stages of these skates. © 2016 The Authors. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of The Fisheries Society of the British Isles.

  14. A role for the CXCR4-CXCL12 axis in the little skate, Leucoraja erinacea.

    Science.gov (United States)

    Hersh, Taylor A; Dimond, Alexandria L; Ruth, Brittany A; Lupica, Noah V; Bruce, Jacob C; Kelley, John M; King, Benjamin L; Lutton, Bram V

    2018-04-11

    The interaction between C-X-C chemokine receptor type 4 (CXCR4) and its cognate ligand, C-X-C motif chemokine ligand 12 (CXCL12), plays a critical role in regulating hematopoietic stem cell activation and subsequent cellular mobilization. Extensive studies of these genes have been conducted in mammals, but much less is known about the expression and function of CXCR4 and CXCL12 in non-mammalian vertebrates. In the present study, we identify simultaneous expression of CXCR4 and CXCL12 orthologues in the epigonal organ (the primary hematopoietic tissue) of the little skate, Leucoraja erinacea. Genetic and phylogenetic analyses were functionally supported by significant mobilization of leukocytes following administration of Plerixafor: a CXCR4 antagonist and clinically important drug. Our results provide evidence that, as in humans, Plerixafor disrupts CXCR4/CXCL12 binding in the little skate, facilitating release of leukocytes into the bloodstream. Our study illustrates the value of the little skate as a model organism, particularly in studies of hematopoiesis, and potentially for pre-clinical research on hematological and vascular disorders.

  15. STUDY CONCERNING THE ELABORATION OF CERTAIN ORIENTATION MODELS AND THE INITIAL SELECTION FOR SPEED SKATING

    Directory of Open Access Journals (Sweden)

    Vaida Marius

    2009-12-01

    Full Text Available In realizing this study I started from the premise that, by elaborating certain orientation models and initial selection for the speed skating and their application will appear superior results, necessary results, taking into account the actual evolution of the high performance sport in general and of the speed skating, in special.The target of this study has been the identification of an orientation model and a complete initial selection that should be based on the favorable aptitudes of the speed skating. On the basis of the made researched orientation models and initial selection has been made, things that have been demonstrated experimental that are not viable, the study starting from the data of the 120 copies, the complete experiment being made by 32 subjects separated in two groups, one using the proposed model and the other formed fromsubjects randomly selected.These models can serve as common working instruments both for the orientation process and for the initial selection one, being able to integrate in the proper practical activity, these being used easily both by coaches that are in charge with the proper selection of the athletes but also by the physical education teachers orschool teachers that are in contact with children of an early age.

  16. Selected plantar pressure characteristics associated with the skating performance of national in-line speed skaters.

    Science.gov (United States)

    Wu, Wen-Lan; Hsu, Hsiu-Tao; Chu, I-Hua; Tsai, Feng-Hua; Liang, Jing-Min

    2017-06-01

    In order to help coaches analyse the techniques of professional in-line speed skaters for making the required fine adjustments and corrections in their push-off work, this study analysed the specific plantar pressure characteristics during a 300-m time-trial test. Fourteen elite in-line speed skaters from the national team were recruited in this study. The total completion time of the 300-m time-trial test, duration of each skating phase, and plantar pressure distribution were measured. The correlation between plantar pressure distribution and skating performance was assessed using Pearson correlation analyses. The results showed that the contact time of the total foot and force-time integral (FTI) in the medial forefoot were significantly correlated with the duration of the start phase, and the FTIs in the medial forefoot of the gliding (left) leg and lateral forefoot of the pushing (right) leg were significantly correlated with the duration of the turning phase. The maximum force in the medial heel, medial forefoot, and median forefoot and the FTI in the medial heel and medial forefoot were significantly correlated with the duration of the linear acceleration phase. The results suggest that a correct plantar loading area and push-off strategy can enhance the skating performance.

  17. Effects of frequency on gross efficiency and performance in roller ski skating.

    Science.gov (United States)

    Leirdal, S; Sandbakk, O; Ettema, G

    2013-06-01

    The purpose of the present study was to examine the effect of frequency on efficiency and performance during G3 roller ski skating. Eight well-trained male cross-country skiers performed three submaximal 5-min speeds (10, 13, and 16 km/h) and a time-to-exhaustion (TTE) performance (at 20 km/h) using the G3 skating technique using freely chosen, high, and low frequency at all four speeds. All tests were done using roller skis on a large treadmill at 5% incline. Gross efficiency (GE) was calculated as power divided by metabolic rate. Power was calculated as the sum of power against frictional forces and power against gravity. Metabolic rate was calculated from oxygen consumption and blood lactate concentration. Freely chosen frequency increased from 60 to 70 strokes/min as speed increased from 10 to 20 km/h. GE increased with power. At high power (20 km/h performance test), both efficiency and performance were significantly reduced by high frequency. In regard to choice of frequency during G3 roller ski skating, cross-country skiers seems to be self-optimized both in relation to energy saving (efficiency) and performance (TTE). © 2011 John Wiley & Sons A/S.

  18. Great Lakes Ice Charts

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season through the 2001/2002...

  19. Embryo developmental events and the egg case of the Aleutian skate Bathyraja aleutica (Gilbert) and the Alaska skate Bathyraja parmifera (Bean).

    Science.gov (United States)

    Hoff, G R

    2009-02-01

    Embryo development events were correlated with egg-case changes for the Aleutian skate Bathyraja aleutica and the Alaska skate Bathyraja parmifera. Yolk absorption underwent two phases: that of steady absorption during early development and that of rapid yolk absorption during the final development stages. Total length (L(T)) for 50% of the pre-hatching embryos egg-case jelly disappearance was 92.04 mm (range 81-102 mm) and 99.36 mm (range 81-100 mm) for B. aleutica and B. parmifera, respectively, allowing the inner chamber to open to seawater flow. The tail filament underwent three phases of growth: rapid elongation during early development (70 mm L(T) for both species and the sex ratio was 1:1 well before hatching. Egg cases that were devoid of an ova or developing embryo were c. 5.0 and 6.5% of the egg cases examined for B. aleutica and B. parmifera, respectively. Measurements showed that egg cases containing only egg jelly were smaller in both width and length than those possessing an ova. Embryo stages were punctuated with distinct events that correlated with egg case changes controlling the internal environment of the developing embryo.

  20. Age group athletes in inline skating: decrease in overall and increase in master athlete participation in the longest inline skating race in Europe - the Inline One-Eleven.

    Science.gov (United States)

    Teutsch, Uwe; Knechtle, Beat; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

    2013-01-01

    Participation and performance trends in age group athletes have been investigated in endurance and ultraendurance races in swimming, cycling, running, and triathlon, but not in long-distance inline skating. The aim of this study was to investigate trends in participation, age, and performance in the longest inline race in Europe, the Inline One-Eleven over 111 km, held between 1998 and 2009. The total number, age distribution, age at the time of the competition, and race times of male and female finishers at the Inline One-Eleven were analyzed. Overall participation increased until 2003 but decreased thereafter. During the 12-year period, the relative participation in skaters younger than 40 years old decreased while relative participation increased for skaters older than 40 years. The mean top ten skating time was 199 ± 9 minutes (range: 189-220 minutes) for men and 234 ± 17 minutes (range: 211-271 minutes) for women, respectively. The gender difference in performance remained stable at 17% ± 5% across years. To summarize, although the participation of master long-distance inline skaters increased, the overall participation decreased across years in the Inline One-Eleven. The race times of the best female and male skaters stabilized across years with a gender difference in performance of 17% ± 5%. Further studies should focus on the participation in the international World Inline Cup races.

  1. Molecular Characterization of the Skate Peripherin/rds Gene: Relationship to Its Orthologues and Paralogues

    Science.gov (United States)

    Li, Chibo; Ding, Xi-Qin; O’Brien, John; Al-Ubaidi, Muayyad R.

    2010-01-01

    PURPOSE A great deal of information about functionally significant domains of a protein may be obtained by comparison of primary sequences of gene homologues over a broad phylogenetic base. This study was designed to identify evolutionarily conserved domains of the photoreceptor disc membrane protein peripherin/rds by analysis of the homologue in a primitive vertebrate, the skate. METHODS A skate retinal cDNA library was screened using a mouse peripherin/rds clone. The 5′ and 3′ untranslated regions of the skate peripherin/rds (srds) cDNA were isolated by the rapid amplification of cDNA ends (RACE) approach. The gene structure was characterized by PCR amplification and sequencing of genomic fragments. Northern and Western blot analyses were used to identify srds transcript and protein, respectively. RESULTS A new homologue of peripherin/rds was identified from the skate retinal cDNA library. SRDS is a glycoprotein with a predicted molecular mass of 40.2 kDa. The srds gene consists of two exons and one small intron and transcribes into a single 6-kb message. Phylogenetic analysis places SRDS at the base of peripherin/rds family and near the division of that group and the branch leading to rds-like and rom-1 genes. SRDS protein is 54.5% identical with peripherin/rds across species. Identity is significantly higher (73%) in the intradiscal domains. Sequence comparison revealed the conservation of all residues that have been shown, on mutation, to associate with retinitis pigmentosa and showed conservation of most residues associated with macular dystrophies. Comparison with ROM-1 and other rds-like proteins revealed the presence of a highly conserved domain in the large intradiscal loop. CONCLUSIONS Srds represents the skate orthologue of mammalian peripherin/rds genes. Conservation of most of the residues associated with human retinal diseases indicates that these residues serve important functional roles. The high degree of conservation of a short stretch within

  2. Measuring is winning. FlevOnice reduces energy consumption by 50%; Meten is winnen. FlevOnice halveert energiegebruik

    Energy Technology Data Exchange (ETDEWEB)

    Van der Stoel, H. [Sparkling Projects, Apeldoorn (Netherlands)

    2011-01-15

    FlevOnice is a 5 kilometers outdoor speed skating rink in Biddinghuizen, Netherlands. This article addresses what is needed to conduct good measurements aimed at maintaining the ice floor of FlevOnice and to save energy. [Dutch] FlevOnice is een vijf kilometer lange buiten gelegen ijsbaan in Biddinghuizen. In dit artikel wordt aandacht besteed aan wat nodig is om goede metingen uit te voeren waarmee de ijsvloer van FlevOnice kan worden onderhouden en waarmee energie kan worden bespaard.

  3. Energy models. Integrated heating and cooling in different sports fields and halls; Energiamalli. Urheilupaikkojen integroitu laemmitys ja jaeaehdytys (UPILAEJAE)

    Energy Technology Data Exchange (ETDEWEB)

    Aittomaeki, A.; Maekinen, A.

    2009-07-01

    The efficient use of energy is playing an increasing role in saving natural resources and in maintaining competitiveness. The system integration plays an essential role when efficiency is maximized. Expressed in thermodynamical terms the question is about minimizing the loss of energy. When planning the integration of heating and cooling the impacts of different coupling possibilities and measurements should be compared. In this report the modeling or simulation of energy balances studies in different systems is described. In the system integration of different sports buildings the modeling parts are the following: office space with heating systems, indoor ice-skating rink, skiing tunnel, indoor swimming pool, sports-field and sport center

  4. Physiological and technical commitment during a 300-m in-line skating trial in athletes of different age categories.

    Science.gov (United States)

    Invernizzi, Pietro L; Scurati, Raffaele; Crotti, Matteo; Bosio, Andrea; Longo, Stefano; Esposito, Fabio

    2018-01-04

    This study investigated the differences in strength, technique and time performance in in-line skaters of three age categories during a 300 m trial. Possible correlations among these variables were also assessed. Thirty-six elite in-line skaters (Cadets, Juniors and Seniors, n=12 each; 14±1, 16±1, and 24±6 years of age, respectively) performed a 300-m trial on an outdoor oval track. Total time (Ttot), 100-m fractions and duration of each skating technique (initial acceleration phase, straight push and cross-over) were recorded. A squat jump (SJ) was performed before and after the trial. Heart rate, blood lactate concentration ([La-]) and rate of perceived exertion (RPE) were collected before, during and at the end of the trial. Ttot was longer and SJ lower in Cadets compared to the other groups. Seniors employed the cross-over technique for a longer period than the straight push technique, compared to Juniors and Cadets. Ttot correlated negatively with SJ in Seniors. The number of significant correlations between skating techniques' duration and both Ttot and SJ increased with age category. No differences among groups were found for heart rate, [La-] and RPE. With increasing age category, leg strength appeared to be the more related aspect to skating performance. To improve 300-m in-line skating performance, trainers should pay particular attention to the enhancement of leg strength and cross-over skating technique.

  5. A esportivização do skate (1960-1990: relações entre o macro e o micro

    Directory of Open Access Journals (Sweden)

    Tony Honorato

    2013-03-01

    Full Text Available O objetivo deste estudo foi apresentar elementos da esportivização da prática cultural skate (1960-1990, como conhecimento para o entendimento da relação entre o micro e o macro processo sócio-histórico do skate. Como fonte de pesquisa histórica para a esportivização do skate no Brasil, dimensão macro, utilizamos a Revista Tribo Skate e para a de Piracicaba/SP, dimensão micro, entrevistamos dois colaboradores a partir do método da história oral. Os resultados evidenciaram que o skate surgiu para gerar fortes tensões agradáveis, suas formas de lazer precedem as formas esportivas e, guardadas as particularidades, os seus processos macro e micro-históricos são interdependentes.

  6. A esportivização do skate (1960-1990): relações entre o macro e o micro

    OpenAIRE

    Honorato, Tony

    2013-01-01

    O objetivo deste estudo foi apresentar elementos da esportivização da prática cultural skate (1960-1990), como conhecimento para o entendimento da relação entre o micro e o macro processo sócio-histórico do skate. Como fonte de pesquisa histórica para a esportivização do skate no Brasil, dimensão macro, utilizamos a Revista Tribo Skate e para a de Piracicaba/SP, dimensão micro, entrevistamos dois colaboradores a partir do método da história oral. Os resultados evidenciaram que o skate surgiu ...

  7. A new temperate deepwater skate of the genus Bathyraja (Rajoidei: Arhynchobatidae) from the South-West Pacific.

    Science.gov (United States)

    Last, Peter R; Stewart, Andrew L; Séret, Bernard

    2016-06-28

    A single specimen of a new Bathyraja skate was collected by the authors in 2003 during a survey of the deepwater biota of the northern Tasman Sea by the New Zealand FRV Tangaroa. This skate, labelled the 'blonde skate' by voyage participants, is uniformly white on all surfaces of the body and the skin is partly translucent. It belongs to a subgroup of Bathyraja with a large, almost smooth, quadrangular disc and well-developed and equally spaced median tail thorns. Other similar and probably closely related Bathyraja specimens have been caught in seas to the south of New Zealand since the discovery of this species, but their identity is yet to be confirmed.

  8. Characterization of little skate (Leucoraja erinacea) recombinant transthyretin: Zinc-dependent 3,3',5-triiodo-l-thyronine binding.

    Science.gov (United States)

    Suzuki, Shunsuke; Kasai, Kentaro; Yamauchi, Kiyoshi

    2015-01-01

    Transthyretin (TTR) diverged from an ancestral 5-hydroxyisourate hydrolase (HIUHase) by gene duplication at some early stage of chordate evolution. To clarify how TTR had participated in the thyroid system as an extracellular thyroid hormone (TH) binding protein, TH binding properties of recombinant little skate Leucoraja erinacea TTR was investigated. At the amino acid level, skate TTR showed 37-46% identities with the other vertebrate TTRs. Because the skate TTR had a unique histidine-rich segment in the N-terminal region, it could be purified by Ni-affinity chromatography. The skate TTR was a 46-kDa homotetramer of 14.5kDa subunits, and had one order of magnitude higher affinity for 3,3',5-triiodo-l-thyronine (T3) and some halogenated phenols than for l-thyroxine. However, the skate TTR had no HIUHase activity. Ethylenediaminetetraacetic acid (EDTA) treatment inhibited [(125)I]T3 binding activity whereas the addition of Zn(2+) to the EDTA-treated TTR recovered [(125)I]T3 binding activity in a Zn(2+) concentration-dependent manner. Scatchard analysis revealed the presence of two classes of binding site for T3, with dissociation constants of 0.24 and 17nM. However, the high-affinity sites were completely abolished with 1mM EDTA, whereas the remaining low-affinity sites decreased binding capacity. The number of zinc per TTR was quantified to be 4.5-6.3. Our results suggest that skate TTR has tight Zn(2+)-binding sites, which are essential for T3 binding to at least the high-affinity sites. Zn(2+) binding to the N-terminal histidine-rich segment may play an important role in acquisition or reinforcement of TH binding ability during early evolution of TTR. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Getting in shape: Reconstructing three-dimensional long-track speed skating kinematics by comparing several body pose reconstruction techniques.

    Science.gov (United States)

    van der Kruk, E; Schwab, A L; van der Helm, F C T; Veeger, H E J

    2018-03-01

    In gait studies body pose reconstruction (BPR) techniques have been widely explored, but no previous protocols have been developed for speed skating, while the peculiarities of the skating posture and technique do not automatically allow for the transfer of the results of those explorations to kinematic skating data. The aim of this paper is to determine the best procedure for body pose reconstruction and inverse dynamics of speed skating, and to what extend this choice influences the estimation of joint power. The results show that an eight body segment model together with a global optimization method with revolute joint in the knee and in the lumbosacral joint, while keeping the other joints spherical, would be the most realistic model to use for the inverse kinematics in speed skating. To determine joint power, this method should be combined with a least-square error method for the inverse dynamics. Reporting on the BPR technique and the inverse dynamic method is crucial to enable comparison between studies. Our data showed an underestimation of up to 74% in mean joint power when no optimization procedure was applied for BPR and an underestimation of up to 31% in mean joint power when a bottom-up inverse dynamics method was chosen instead of a least square error approach. Although these results are aimed at speed skating, reporting on the BPR procedure and the inverse dynamics method, together with setting a golden standard should be common practice in all human movement research to allow comparison between studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Differences in Muscle Oxygenation, Perceived Fatigue and Recovery between Long-Track and Short-Track Speed Skating.

    Science.gov (United States)

    Hettinga, Florentina J; Konings, Marco J; Cooper, Chris E

    2016-01-01

    Due to the technical nature of speed skating, that is affecting physiological mechanisms such as oxygenation and blood flow, this sport provides a unique setting allowing us to uncover novel mechanistic insights of the physiological response to exercise in elite middle-distance and endurance sports. The present study aimed to examine the influence of skating mode (short-track vs. long-track) on muscle oxygenation, perceived fatigue, and recovery in elite speed skating. Muscle oxygenation of 12 talented short-track speed skaters was continuously monitored during a long-track (LT) and a short-track (ST) skating time-trial of maximal effort using near-infrared spectroscopy (NIRS) on the m. vastus lateralis for both legs. Video captures were made of each testing session for further interpretation of the muscle oxygenation. To determine recovery, perceived exertion was measured 2 and 4 h after each testing sessions. Repeated measures ANOVA's were used for statistical analysis ( p skating (TSI%-slope: left = 0.050 ± 0.052, right = 0.001 ± 0.053, p skating modes in muscle oxygenation. Respectively, two ( ST = 5.8 ± 2.0; LT = 4.2 ± 1.5) and 4 h ( ST = 4.6 ± 1.9; LT = 3.1 ± 1.6) after the time-trials, a higher rate of perceived exertion was found for ST. Based on our results, ST seems more physiologically demanding, and longer periods of recovery are needed after training compared to LT. Technical aspects unique to the exercise mode seem to impact on oxygenation, affecting processes related to the regulation of exercise intensity such as fatigue and recovery.

  11. Alterations in aerobic energy expenditure and neuromuscular function during a simulated cross-country skiathlon with the skating technique.

    Science.gov (United States)

    Fabre, Nicolas; Mourot, Laurent; Zoppirolli, Chiara; Andersson, Erik; Willis, Sarah J; Holmberg, Hans-Christer

    2015-04-01

    Here, we tested the hypothesis that aerobic energy expenditure (AEE) is higher during a simulated 6-km (2 loops of 3-km each) "skiathlon" than during skating only on a treadmill and attempted to link any such increase to biomechanical and neuromuscular responses. Six elite male cross-country skiers performed two pre-testing time-trials (TT) to determine their best performances and to choose an appropriate submaximal speed for collection of physiological, biomechanical and neuromuscular data during two experimental sessions (exp). Each skier used, in randomized order, either the classical (CL) or skating technique (SK) for the first 3-km loop, followed by transition to the skating technique for the second 3-km loop. Respiratory parameters were recorded continuously. The EMG activity of the triceps brachii (TBr) and vastus lateralis (VLa) muscles during isometric contractions performed when the skiers were stationary (i.e., just before the first loop, during the transition, and after the second loop); their corresponding activity during dynamic contractions; and pole and plantar forces during the second loop were recorded. During the second 3-km of the TT, skating speed was significantly higher for the SK-SK than CL-SK. During this second loop, AEE was also higher (+1.5%) for CL-SKexp than SK-SKexp, in association with higher VLa EMG activity during both isometric and dynamic contractions, despite no differences in plantar or pole forces, poling times or cycle rates. Although the underlying mechanism remains unclear, during a skiathlon, the transition between the sections of classical skiing and skating alters skating performance (i.e., skiing speed), AEE and neuromuscular function. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Dead-ice environments

    DEFF Research Database (Denmark)

    Krüger, Johannes; Kjær, Kurt H.; Schomacker, Anders

    2010-01-01

    glacier environment. The scientific challenges are to answer the key questions. What are the conditions for dead-ice formation? From which sources does the sediment cover originate? Which melting and reworking processes act in the ice-cored moraines? What is the rate of de-icing in the ice-cored moraines...

  13. DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in 'ray' products sold across Ireland and the UK.

    Science.gov (United States)

    Griffiths, Andrew Mark; Miller, Dana D; Egan, Aaron; Fox, Jennifer; Greenfield, Adam; Mariani, Stefano

    2013-01-01

    Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of "skate" or "ray". The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., "winged") and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a single retailer

  14. The phylogenetic position of the roughskin skate Dipturus trachyderma (Krefft & Stehmann, 1975) (Rajiformes, Rajidae) inferred from the mitochondrial genome.

    Science.gov (United States)

    Vargas-Caro, Carolina; Bustamante, Carlos; Lamilla, Julio; Bennett, Michael B; Ovenden, Jennifer R

    2016-07-01

    The complete mitochondrial genome of the roughskin skate Dipturus trachyderma is described from 1 455 724 sequences obtained using Illumina NGS technology. Total length of the mitogenome was 16 909 base pairs, comprising 2 rRNAs, 13 protein-coding genes, 22 tRNAs and 2 non-coding regions. Phylogenetic analysis based on mtDNA revealed low genetic divergence among longnose skates, in particular, those dwelling the continental shelf and slope off the coasts of Chile and Argentina.

  15. Rate of ice accumulation during ice storms

    Energy Technology Data Exchange (ETDEWEB)

    Feknous, N. [SNC-Lavalin, Montreal, PQ (Canada); Chouinard, L. [McGill Univ., Montreal, PQ (Canada); Sabourin, G. [Hydro-Quebec, Montreal, PQ (Canada)

    2005-07-01

    The rate of glaze ice accumulation is the result of a complex process dependent on numerous meteorological and physical factors. The aim of this paper was to estimate the distribution rate of glaze ice accumulation on conductors in southern Quebec for use in the design of mechanical and electrical de-icing devices. The analysis was based on direct observations of ice accumulation collected on passive ice meters. The historical database of Hydro-Quebec, which contains observations at over 140 stations over period of 25 years, was used to compute accumulation rates. Data was processed so that each glaze ice event was numbered in a chronological sequence. Each event consisted of the time series of ice accumulations on each of the 8 cylinders of the ice meters, as well as on 5 of its surfaces. Observed rates were converted to represent the average ice on a 30 mm diameter conductor at 30 m above ground with a span of 300 m. Observations were corrected to account for the water content of the glaze ice as evidenced by the presence of icicles. Results indicated that despite significant spatial variations in the expected severity of ice storms as a function of location, the distribution function for rates of accumulation were fairly similar and could be assumed to be independent of location. It was concluded that the observations from several sites could be combined in order to obtain better estimates of the distribution of hourly rates of ice accumulation. However, the rates were highly variable. For de-icing strategies, it was suggested that average accumulation rates over 12 hour periods were preferable, and that analyses should be performed for other time intervals to account for the variability in ice accumulation rates over time. In addition, accumulation rates did not appear to be highly correlated with average wind speed for maximum hourly accumulation rates. 3 refs., 2 tabs., 10 figs.

  16. Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

    Directory of Open Access Journals (Sweden)

    Carolin Stangier, Thomas Abel, Julia Mierau, Wildor Hollmann, Heiko K. Strüder

    2016-03-01

    Full Text Available The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour for 8 weeks. Training intensity was determined within non-specific (cycling or running and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m and one non-specific (30s cycling or 200m running all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa and glucose (BGL 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak was significantly increased (+17%; p = 0.01 in both groups and highly correlated with the sprint performance (r = -0.71. BLa values decreased significantly (-18%, p = 0.02 after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04 in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group.

  17. Pacing Behavior and Tactical Positioning in 1500-m Short-Track Speed Skating.

    Science.gov (United States)

    Konings, Marco J; Noorbergen, Olaf S; Parry, David; Hettinga, Florentina J

    2016-01-01

    To gain more insight in pacing behavior and tactical positioning in 1500-m short-track speed skating, a sport in which several athletes directly compete in the same race. Lap times and intermediate rankings of elite 1500-m short-track- skating competitors were collected over the season 2012-13 (N = 510, 85 races). Two statistical approaches were used to assess pacing behavior and tactical positioning. First, lap times were analyzed using a MANOVA, and for each lap differences between sex, race type, final rankings, and stage of competition were determined. Second, Kendall tau b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined. In 1500 m (13.5 laps of 111.12 m), correlations between intermediate and final ranking gradually increased throughout the race (eg, lap 1, r = .05; lap 7, r = .26; lap 13, r = .85). Moreover, the percentage of race winners skating in the leading position was over 50% during the last 3 laps. Top finishers were faster than bottom-place finishers only during the last 5 laps, with on average 0.1- to 1.5-s faster lap times of the race winners compared with the others during the last 5 laps. Although a fast start led to faster finishing times, top finishers were faster than bottom-placed finishers only during the last 5 laps. Moreover, tactical positioning at 1 of the foremost positions during the latter phase of the race appeared to be a strong determinant of finishing position.

  18. Identification of potential essential fish habitats for skates based on fishers' knowledge.

    Science.gov (United States)

    Serra-Pereira, Bárbara; Erzini, Karim; Maia, Catarina; Figueiredo, Ivone

    2014-05-01

    Understanding of spatio-temporal patterns of sensitive fish species such as skates (Rajidae) is essential for implementation of conservation measures. With insufficient survey data available for these species in Portuguese Continental waters, this study shows that fishery-dependent data associated with fishers' knowledge can be used to identify potential Essential Fish Habitats (EFH) for seven skate species. Sites with similar geomorphology were associated with the occurrence of juveniles and/or adults of the same group of species. For example, sites deeper than 100 m with soft sediment include predominantly adults of Raja clavata, and are the habitat for egg deposition of this species. Raja undulata and R. microocellata are the more coastal species, preferring sand or gravel habitats, while coastal areas with rocks and sand seabed are potential nursery areas for R. brachyura, R. montagui and R. clavata. The main output of this study is the identification of preferential fishing sites enclosing potential EFH for some species, associated with egg-laying and nursery grounds. The location of these areas will be considered for future seasonal closures, and studies will be conducted to evaluate the biological and socio-economic impacts of such measures. As in the past, fishermen will collaborate in the process of evaluating those impacts, since they have practical and applied knowledge that is extremely valuable for evaluating the advantages and disadvantages of such closures. In conclusion, this study is a first contribution to the understanding and identification of EFH for skate species, associated with nursery and egg deposition sites, with direct application to management.

  19. Identification of Potential Essential Fish Habitats for Skates Based on Fishers' Knowledge

    Science.gov (United States)

    Serra-Pereira, Bárbara; Erzini, Karim; Maia, Catarina; Figueiredo, Ivone

    2014-05-01

    Understanding of spatio-temporal patterns of sensitive fish species such as skates (Rajidae) is essential for implementation of conservation measures. With insufficient survey data available for these species in Portuguese Continental waters, this study shows that fishery-dependent data associated with fishers' knowledge can be used to identify potential Essential Fish Habitats (EFH) for seven skate species. Sites with similar geomorphology were associated with the occurrence of juveniles and/or adults of the same group of species. For example, sites deeper than 100 m with soft sediment include predominantly adults of Raja clavata, and are the habitat for egg deposition of this species. Raja undulata and R. microocellata are the more coastal species, preferring sand or gravel habitats, while coastal areas with rocks and sand seabed are potential nursery areas for R. brachyura, R. montagui and R. clavata. The main output of this study is the identification of preferential fishing sites enclosing potential EFH for some species, associated with egg-laying and nursery grounds. The location of these areas will be considered for future seasonal closures, and studies will be conducted to evaluate the biological and socio-economic impacts of such measures. As in the past, fishermen will collaborate in the process of evaluating those impacts, since they have practical and applied knowledge that is extremely valuable for evaluating the advantages and disadvantages of such closures. In conclusion, this study is a first contribution to the understanding and identification of EFH for skate species, associated with nursery and egg deposition sites, with direct application to management.

  20. Preliminary observations on the effects of selenate on the development of the embryonic skate, Raja eglanteria

    Science.gov (United States)

    Conrad, G. W.; Luer, C. A.; Paulsen, A. Q.; Funderburgh, J. L.; Spooner, B. S. (Principal Investigator)

    1993-01-01

    Morphogenesis of the clearnose skate, Raja eglanteria, was not significantly inhibited as a result of 7 days of exposure to 1-2 mM selenate in the sea water during Days 59-69 of embryonic development (hatching would normally have occurred at 82 +/- 4 days of incubation). Although corneal transparency appeared normal in the eye, preliminary measurements of the thickness of Bowman's layer of the cornea suggested that it was significantly thinner in the corneas of embryos exposed to 1-2 mM selenate. Selenate is an ion reported to inhibit sulfation of glycosaminoglycans in connective tissue.

  1. Survey of Antibiotic-producing Bacteria Associated with the Epidermal Mucus Layers of Rays and Skates

    Directory of Open Access Journals (Sweden)

    Kim B. Ritchie

    2017-07-01

    Full Text Available Elasmobranchs represent a distinct group of cartilaginous fishes that harbor a remarkable ability to heal wounds rapidly and without infection. To date very little work has addressed this phenomenon although it is suggested that antibiotic capabilities associated with epidermal surfaces may be a factor. The study of benefits derived from mutualistic interactions between unicellular and multicellular organisms is a rapidly growing area of research. Here we survey and identify bacterial associates of three ray and one skate species in order to assess the potential for antibiotic production from elasmobranch associated bacteria as a novel source for new antibiotics.

  2. Reception of low-intensity millimeter-wave electromagnetic radiation by the electroreceptors in skates

    International Nuclear Information System (INIS)

    Akoev, G.N.; Avelev, V.D.

    1995-01-01

    Low intensity millimeter-wave electromagnetic radiation of less than 10 mW cm -2 power intensity has a nonthermal effect on the body and it is widely used in medical practice for treatment of various diseases. Nevertheless, the effect of EMR on biological tissues is not understood. The skin and its sensory receptors are considered to be responsible for EMR reception, but this has yet to be confirmed. The present experiments were designed to study the effect of millimeter-wave electromagnetic radiation on the ampullae of Lorenzini in skates, which are very sensitive to weak electrical stimuli at low frequency. (author)

  3. Effects of Cycling Versus Running Training on Sprint and Endurance Capacity in Inline Speed Skating

    Science.gov (United States)

    Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K.

    2016-01-01

    The purpose of this study was to compare the effects of running versus cycling training on sprint and endurance capacity in inline speed skating. Sixteen elite athletes (8 male, 8 female, 24 ± 8 yrs) were randomly assigned into 2 training groups performing either 2 session per week of treadmill running or ergometer cycling in addition to 3 skating specific sessions (technique, plyometrics, parkour) for 8 weeks. Training intensity was determined within non-specific (cycling or running) and effects on specific endurance capacity within a specific incremental exercise test. Before and after the intervention all athletes performed a specific (300m) and one non-specific (30s cycling or 200m running) all-out sprint test according to the group affiliation. To determine the accumulation of blood lactate (BLa) and glucose (BGL) 20 μl arterialized blood was drawn at rest, as well as in 1 min intervals for 10 min after the sprint test. The sport-specific peak oxygen uptake (VO2 peak) was significantly increased (+17%; p = 0.01) in both groups and highly correlated with the sprint performance (r = -0.71). BLa values decreased significantly (-18%, p = 0.02) after the specific sprint test from pre to post-testing without any group effect. However, BGL values only showed a significant decrease (-2%, p = 0.04) in the running group. The close relationship between aerobic capacity and sprint performance in inline speed skating highlights the positive effects of endurance training. Although both training programs were equally effective in improving endurance and sprint capacities, the metabolic results indicate a faster recovery after high intensity efforts for all athletes, as well as a higher reliance on the fat metabolism for athletes who trained in the running group. Key points In addition to a highly developed aerobic performance inline speed skaters also require a highly trained anaerobic capacity to be effective in the sprint sections such as the mass start, tactical attacks

  4. Lower Leg Anterior and Lateral Intracompartmental Pressure Changes Before and After Classic Versus Skate Nordic Rollerskiing.

    Science.gov (United States)

    Woods, Katherine M; Petron, David J; Shultz, Barry B; Hicks-Little, Charlie A

    2015-08-01

    Chronic exertional compartment syndrome (CECS) is a debilitating condition resulting in loss of function and a decrease in athletic performance. Cases of CECS are increasing among Nordic skiers; therefore, analysis of intracompartmental pressures (ICPs) before and after Nordic skiing is warranted. To determine if lower leg anterior and lateral ICPs and subjective lower leg pain levels increased after a 20-minute Nordic rollerskiing time trial and to examine if differences existed between postexercise ICPs for the 2 Nordic rollerskiing techniques, classic and skate. Crossover study. Outdoor paved loop. Seven healthy Division I Nordic skiers (3 men, 4 women; age = 22.71 ± 1.38 y, height = 175.36 ± 6.33 cm, mass = 70.71 ± 6.58 kg). Participants completed two 20-minute rollerskiing time trials using the classic and skate technique in random order. The time trials were completed 7 days apart. Anterior and lateral ICPs and lower leg pain scores were obtained at baseline and at minutes 1 and 5 after rollerskiing. Anterior and lateral ICPs (mm Hg) were measured using a Stryker Quic STIC handheld monitor. Subjective measures of lower leg pain were recorded using the 11-point Numeric Rating Scale. Increases in both anterior (P = .000) and lateral compartment (P = .002) ICPs were observed, regardless of rollerskiing technique used. Subjective lower leg pain increased after the classic technique for the men from baseline to 1 minute postexercise and after the skate technique for the women. Significant 3-way interactions (technique × time × sex) were observed for the anterior (P = .002) and lateral (P = .009) compartment ICPs and lower leg pain (P = .005). Postexercise anterior and lateral ICPs increased compared with preexercise ICPs after both classic and skate rollerskiing techniques. Lower leg pain is a primary symptom of CECS. The subjective lower leg pain 11-point Numeric Rating Scale results indicate that increases in lower leg ICPs sustained during Nordic

  5. Conservative management of an elite ice hockey goaltender with femoroacetabular impingement (FAI): a case report

    Science.gov (United States)

    MacIntyre, Kyle; Gomes, Brendan; MacKenzie, Steven; D’Angelo, Kevin

    2015-01-01

    Objective: To detail the presentation of an elite male ice hockey goaltender with cam-type femoroacetabular impingement (FAI) and acetabular labral tears. This case will outline the prevalence, clinical presentation, imaging criteria, pathomechanics, and management of FAI, with specific emphasis on the ice hockey goaltender. Clinical Features: A 22-year old retired ice hockey goaltender presented to a chiropractor after being diagnosed by an orthopaedic surgeon with MRI confirmed left longitudinal and chondral flap acetabular labral tears and cam-type femoroacetabular impingement (FAI). As the patient was not a candidate for surgical intervention, a multimodal conservative treatment approach including manual therapy, electroacupuncture and rehabilitation exercises were implemented. Summary: FAI is prevalent in ice hockey players, particularly with goaltenders. Both skating and position-dependent hip joint mechanics involved in ice hockey may exacerbate or contribute to acquired and congenital forms of symptomatic FAI. As such, practitioners managing this population must address sport-specific demands in manual therapy, rehabilitation and physical training, to improve functional outcomes and prevent future injury. PMID:26816416

  6. Stochastic ice stream dynamics.

    Science.gov (United States)

    Mantelli, Elisa; Bertagni, Matteo Bernard; Ridolfi, Luca

    2016-08-09

    Ice streams are narrow corridors of fast-flowing ice that constitute the arterial drainage network of ice sheets. Therefore, changes in ice stream flow are key to understanding paleoclimate, sea level changes, and rapid disintegration of ice sheets during deglaciation. The dynamics of ice flow are tightly coupled to the climate system through atmospheric temperature and snow recharge, which are known exhibit stochastic variability. Here we focus on the interplay between stochastic climate forcing and ice stream temporal dynamics. Our work demonstrates that realistic climate fluctuations are able to (i) induce the coexistence of dynamic behaviors that would be incompatible in a purely deterministic system and (ii) drive ice stream flow away from the regime expected in a steady climate. We conclude that environmental noise appears to be crucial to interpreting the past behavior of ice sheets, as well as to predicting their future evolution.

  7. Sea Ice Ecosystems

    Science.gov (United States)

    Arrigo, Kevin R.

    2014-01-01

    Polar sea ice is one of the largest ecosystems on Earth. The liquid brine fraction of the ice matrix is home to a diverse array of organisms, ranging from tiny archaea to larger fish and invertebrates. These organisms can tolerate high brine salinity and low temperature but do best when conditions are milder. Thriving ice algal communities, generally dominated by diatoms, live at the ice/water interface and in recently flooded surface and interior layers, especially during spring, when temperatures begin to rise. Although protists dominate the sea ice biomass, heterotrophic bacteria are also abundant. The sea ice ecosystem provides food for a host of animals, with crustaceans being the most conspicuous. Uneaten organic matter from the ice sinks through the water column and feeds benthic ecosystems. As sea ice extent declines, ice algae likely contribute a shrinking fraction of the total amount of organic matter produced in polar waters.

  8. O DISCURSO CARISMÁTICO E A ROTINIZAÇÃO DO CARISMA NA SKATE PLAZA DO COMPLEXO AMBIENTAL GOVERNADOR MANOEL RIBAS -PONTA GROSSA - PR

    OpenAIRE

    ADRIANO ALBUQUERQUE BARRETO

    2012-01-01

    As Skate Plazas surgem no início dos anos 2000 como um modelo possível na construção de pistas de skate. Este modelo surgiu na perspectiva de uma construção cada vez mais semelhante dos lugares que se encontram nas ruas das cidades. Até então além dos obstáculos mais comuns encontrados nas ruas, como os caixotes, os trilhos e as escadas, as rampas faziam parte das pistas que vinham sendo construídas. Nos modelos mais recentes de Skate Plaza vemos com menor intensidade a este tipo de obs...

  9. Ross Ice Shelf, Antarctic Ice and Clouds

    Science.gov (United States)

    1991-01-01

    In this view of Antarctic ice and clouds, (56.5S, 152.0W), the Ross Ice Shelf of Antarctica is almost totally clear, showing stress cracks in the ice surface caused by wind and tidal drift. Clouds on the eastern edge of the picture are associated with an Antarctic cyclone. Winds stirred up these storms have been known to reach hurricane force.

  10. The role of incline, performance level and gender on the gross mechanical efficiency of roller ski skating

    Directory of Open Access Journals (Sweden)

    Øyvind eSandbakk

    2013-10-01

    Full Text Available The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points (the Federation of International Skiing approved scoring system for ski racing where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r=-0.89-0.98 and P

  11. 77 FR 10463 - Fisheries of the Northeastern United States; Proposed 2012-2013 Northeast Skate Complex Fishery...

    Science.gov (United States)

    2012-02-22

    ... information on skates. The ABC is calculated by multiplying the median catch/biomass ratio by the most recent... readily available, and individual vessel profitability cannot be determined directly; therefore, expected changes in gross revenues were used as a proxy for profitability. This action does not introduce any new...

  12. Gastric inhibitory peptide, serotonin, and glucagon are unexpected chloride secretagogues in the rectal gland of the skate (Leucoraja erinacea).

    Science.gov (United States)

    Kelley, Catherine A; Decker, Sarah E; Silva, Patricio; Forrest, John N

    2014-05-01

    Since the discovery of the rectal gland of the dogfish shark 50 years ago, experiments with this tissue have greatly aided our understanding of secondary active chloride secretion and the secretagogues responsible for this function. In contrast, very little is known about the rectal gland of skates. In the present experiments, we performed the first studies in the perfused rectal gland of the little skate (Leucoraja erinacea), an organ weighing less than one-tenth of the shark rectal gland. Our results indicate that the skate gland can be studied by modified perfusion techniques and in primary culture monolayers, and that secretion is blocked by the inhibitors of membrane proteins required for secondary active chloride secretion. Our major finding is that three G protein-coupled receptor agonists, the incretin gastric inhibitory polypeptide (GIP), also known as glucose-dependent insulinotropic peptide, as well as glucagon and serotonin, are unexpected potent chloride secretagogues in the skate but not the shark. Glucagon stimulated chloride secretion to a mean value of 1,661 ± 587 μeq·h(-1)·g(-1) and serotonin stimulated to 2,893 ± 699 μeq·h(-1)·g(-1). GIP stimulated chloride secretion to 3,733 ± 679 μeq·h(-1)·g(-1) and significantly increased tissue cAMP content compared with basal conditions. This is the first report of GIP functioning as a chloride secretagogue in any species or tissue.

  13. Evaluation of skate meal and sablefish viscera meal as fish meal replacement in diets for Pacific threadfin (Polydactylus saxfilis)

    Science.gov (United States)

    The objectives of this study were to investigate the nutritional value of skate meal (SM) and black cod viscera meal (BCVM) from Alaska and to ascertain their suitability as replacements for commercial pollock fishmeal in diets for Pacific threadfin (Polydactylus sexfilis). Test diets were made by r...

  14. Puberty and Physical Self-Perceptions of Competitive Female Figure Skaters II: Maturational Timing, Skating Context, and Ability Status

    Science.gov (United States)

    Monsma, Eva V.

    2008-01-01

    One study of figure skaters found that menarcheal status was a stronger predictor than age in explaining the variance in their self-perceptions. Postmenarcheal skaters had significantly lower self-esteem and physical self-concept and were less satisfied with their appearance than premenarcheal skaters. Surprisingly, skating context (i.e., skating…

  15. The role of incline, performance level, and gender on the gross mechanical efficiency of roller ski skating.

    Science.gov (United States)

    Sandbakk, Oyvind; Hegge, Ann Magdalen; Ettema, Gertjan

    2013-01-01

    The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level, and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points [the Federation of International Skiing (FIS) approved scoring system for ski racing] where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r = -0.89 to 0.98 and P gender differences being apparent. Significant correlations between gross efficiency and performance level were found for both inclines and genders (r = -0.65 to 0.81 and P genders used less metabolic energy to perform the same amount of work at steeper inclines, and that the better ranked elite male and female skiers skied more efficiently.

  16. DNA barcoding unveils skate (Chondrichthyes: Rajidae) species diversity in ‘ray’ products sold across Ireland and the UK

    Science.gov (United States)

    Egan, Aaron; Fox, Jennifer; Greenfield, Adam; Mariani, Stefano

    2013-01-01

    Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba). Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged”) and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene) was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura), spotted ray (Raja montagui), thornback ray (Raja clavata), cuckoo ray (Leucoraja naevus) small-eyed ray (Raja microocellata) and shagreen ray (Leucoraja fullonica). Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern. Interestingly, a

  17. DNA barcoding unveils skate (Chondrichthyes: Rajidae species diversity in ‘ray’ products sold across Ireland and the UK

    Directory of Open Access Journals (Sweden)

    Andrew Mark Griffiths

    2013-08-01

    Full Text Available Skates are widely consumed across the globe, but many large species are subject to considerable concern regarding their conservation and management. Within Europe such issues have recently driven policy changes so that, for the first time, reports of skate landings now have to be made under species-specific names. Total allowable catches have also been established for many groups, which have been set to zero for a number of the most vulnerable species (e.g., Dipturus batis, Raja undulata and Rostoraja alba. Whilst accurate species identification has become an important issue for landings, the sale of skates is still usually made under a blanket term of “skate” or “ray”. The matter of identifying species of skate is further complicated by their morphologically conservative nature and the fact that they are commercially valued for their wings. Thus, before sale their bodies are usually discarded (i.e., “winged” and often skinned, making morphological identification impossible. For the first time, DNA barcoding (of the mitochondrial COI gene was applied to samples of skate wings from retail outlets across the British Isles, providing insight into which species are sold for consumption. A total of 98 wing samples were analysed, revealing that six species were sold; blonde ray (Raja brachyura, spotted ray (Raja montagui, thornback ray (Raja clavata, cuckoo ray (Leucoraja naevus small-eyed ray (Raja microocellata and shagreen ray (Leucoraja fullonica. Statistical testing demonstrated that there were significant differences in the species sold in the distinct retail groups which suggests complex drivers behind the patterns of sale in skates. The results also indicate that endangered species are not commonly being passed on to consumers. In addition, the practice of selling skate wings under ambiguous labels is highlighted as it makes it extremely difficult for consumers to exercise a right to avoid species of conservation concern

  18. Variations in relative age effects in individual sports: skiing, figure skating and gymnastics.

    Science.gov (United States)

    Baker, Joseph; Janning, Christina; Wong, Harmonie; Cobley, Stephen; Schorer, Jörg

    2014-01-01

    In many sports, policy-makers and administrators employ annual cohorts to reduce differences between athletes during childhood and youth. Although well-intended, unintended relative age effects (RAEs) usually occur. RAEs refer to the specific selection, participation and attainment disadvantages associated with participants' birthdates relative to an arbitrary 'cutoff' date used to group participants within annual age groups. To date, we have little understanding of RAEs in individual sports. In this article, Study 1 considered the presence of RAEs in 1474 ski jumping, 7501 cross-country skiing, 15,565 alpine skiing, 4179 snowboarders and 713 Nordic combined athletes. Chi-square analyses revealed significant RAEs for most of these contexts across sexes. In Study 2, RAEs in the aesthetic sports of figure skating (n=502) and female gymnastics (n=612) were considered. There was no effect for the figure skaters and an atypical effect for the gymnasts. The significant effects across most ski sports coupled with the null effects in figure skating and atypical effect in gymnastics suggest that sport-specific contextual factors are important elements in understanding the mechanisms of RAEs, although further work is necessary to validate these findings.

  19. Analysis of food habits of skate Rioraja agassizii (Elasmobranchii, Rajidae from southern Brazil

    Directory of Open Access Journals (Sweden)

    N. S. Motta

    Full Text Available Abstract Catches and exports of skate Rioraja agassizii place this species as “vulnerable to extinction” on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N, weight (%M, frequency of occurrence (% FO, and index of relative importance (IRI. The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.

  20. Structural and Functional Components of the Skate Sensory Organ Ampullae of Lorenzini.

    Science.gov (United States)

    Zhang, Xing; Xia, Ke; Lin, Lei; Zhang, Fuming; Yu, Yanlei; St Ange, Kalib; Han, Xiaorui; Edsinger, Eric; Sohn, Joel; Linhardt, Robert J

    2018-05-09

    The skate, a cartilaginous fish related to sharks and rays, possesses a unique electrosensitive sensory organ known as the ampullae of Lorenzini (AoL). This organ is responsible for the detection of weak electric field changes caused by the muscle contractions of their prey. While keratan sulfate (KS) is believed to be a component of a jelly that fills this sensory organ and has been credited with its high proton conductivity, modern analytical methods have not been applied to its characterization. Surprisingly, total glycosaminoglycan (GAG) analysis demonstrates that the KS from skate jelly is extraordinarily pure, containing no other GAGs. This KS had a molecular weight of 20 to 30 kDa, consisting primarily of N-linked KS comprised mostly of a monosulfated disaccharide repeating unit, →3) Gal (1→4) GlcNAc6S (1→. Proteomic analysis of AoL jelly suggests that transferrin, keratin, and mucin serve as KS core proteins. Actin and tropomyosin are responsible for assembling the macrostructure of the jelly, and parvalbumin α-like protein and calreticulin regulate calcium and potassium channels involved in the transduction of the electrical signal, once conducted down the AoL by the jelly, serving as the molecular basis for electroreception.

  1. Analysis of food habits of skate Rioraja agassizii (Elasmobranchii, Rajidae) from southern Brazil.

    Science.gov (United States)

    Motta, N S; Della-Fina, N; Souza, C C A; Rodrigues, E S; Amorim, A F

    2016-06-01

    Catches and exports of skate Rioraja agassizii place this species as "vulnerable to extinction" on the IUCN Red List; therefore, biological and ecological knowledge becomes an important instrument for its conservation control. This study described and quantified the diet composition of R. agassizii by means of stomach analysis contents in the periods 2005-2006 and 2012-2013. We analyzed and quantified stomach contents in terms of abundance (%N), weight (%M), frequency of occurrence (% FO), and index of relative importance (IRI). The results showed differences in the food rates between the periods. However, the groups of food items were the same: Teleostei fish, decapods, and mollusks. In 2005-2006, the diet consisted mainly of shrimp, however, in 2012-2013 it consisted of fish, followed by decapods, especially shrimps. The differences in diets may be attributed to shrimp abundance, which do not characterize a change in the eating habits in 2012-2013, because, in addition to fish, shrimps were also important food sources. The presence of a certain prey is more related to its availability rather than the feeding preference of skate. The amount of ingested items is associated to biological and environmental factors, so that further studies relating diet with capture area, seasonality, depth, and other factors should be conducted.

  2. Batoid locomotion: effects of speed on pectoral fin deformation in the little skate, Leucoraja erinacea.

    Science.gov (United States)

    Di Santo, Valentina; Blevins, Erin L; Lauder, George V

    2017-02-15

    Most batoids have a unique swimming mode in which thrust is generated by either oscillating or undulating expanded pectoral fins that form a disc. Only one previous study of the freshwater stingray has quantified three-dimensional motions of the wing, and no comparable data are available for marine batoid species that may differ considerably in their mode of locomotion. Here, we investigate three-dimensional kinematics of the pectoral wing of the little skate, Leucoraja erinacea , swimming steadily at two speeds [1 and 2 body lengths (BL) s -1 ]. We measured the motion of nine points in three dimensions during wing oscillation and determined that there are significant differences in movement amplitude among wing locations, as well as significant differences as speed increases in body angle, wing beat frequency and speed of the traveling wave on the wing. In addition, we analyzed differences in wing curvature with swimming speed. At 1 BL s -1 , the pectoral wing is convex in shape during the downstroke along the medio-lateral fin midline, but at 2 BL s -1 the pectoral fin at this location cups into the flow, indicating active curvature control and fin stiffening. Wing kinematics of the little skate differed considerably from previous work on the freshwater stingray, which does not show active cupping of the whole fin on the downstroke. © 2017. Published by The Company of Biologists Ltd.

  3. Development of real-time PCR assay for genetic identification of the mottled skate, Beringraja pulchra.

    Science.gov (United States)

    Hwang, In Kwan; Lee, Hae Young; Kim, Min-Hee; Jo, Hyun-Su; Choi, Dong-Ho; Kang, Pil-Won; Lee, Yang-Han; Cho, Nam-Soo; Park, Ki-Won; Chae, Ho Zoon

    2015-10-01

    The mottled skate, Beringraja pulchra is one of the commercially important fishes in the market today. However, B. pulchra identification methods have not been well developed. The current study reports a novel real-time PCR method based on TaqMan technology developed for the genetic identification of B. pulchra. The mitochondrial cytochrome oxidase subunit 1 (COI) nucleotide sequences of 29 B. pulchra, 157 skates and rays reported in GenBank DNA database were comparatively analyzed and the COI sequences specific to B. pulchra was identified. Based on this information, a system of specific primers and Minor Groove Binding (MGB) TaqMan probe were designed. The assay successfully discriminated in 29 specimens of B. pulchra and 27 commercial samples with unknown species identity. For B. pulchra DNA, an average Threshold Cycle (Ct) value of 19.1±0.1 was obtained. Among 27 commercial samples, two samples showed average Ct values 19.1±0.0 and 26.7±0.1, respectively and were confirmed to be B. pulchra based on sequencing. The other samples tested showed undetectable or extremely weak signals for the target fragment, which was also consistent with the sequencing results. These results reveal that the method developed is a rapid and efficient tool to identify B. pulchra and might prevent fraud or mislabeling during the distribution of B. pulchra products. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Chondroitin Sulfate-Rich Extract of Skate Cartilage Attenuates Lipopolysaccharide-Induced Liver Damage in Mice.

    Science.gov (United States)

    Song, Yeong Ok; Kim, Mijeong; Woo, Minji; Baek, Jang-Mi; Kang, Keon-Hee; Kim, Sang-Ho; Roh, Seong-Soo; Park, Chan Hum; Jeong, Kap-Seop; Noh, Jeong-Sook

    2017-06-15

    The protective effects of a chondroitin sulfate-rich extract (CSE) from skate cartilage against lipopolysaccharide (LPS)-induced hepatic damage were investigated, and its mechanism of action was compared with that of chondroitin sulfate (CS) from shark cartilage. ICR mice were orally administrated 200 mg/kg body weight (BW) of CS or 400 mg/kg BW of CSE for 3 consecutive days, followed by a one-time intraperitoneal injection of LPS (20 mg/kg BW). The experimental groups were vehicle treatment without LPS injection (NC group), vehicle treatment with LPS injection (LPS group), CS pretreatment with LPS injection (CS group), and CSE pretreatment with LPS injection (CSE group). Hepatic antioxidant enzyme expression levels in the CS and CSE groups were increased relative to those in the LPS group. In LPS-insulted hepatic tissue, inflammatory factors were augmented relative to those in the NC group, but were significantly suppressed by pretreatment with CS or CSE. Moreover, CS and CSE alleviated the LPS-induced apoptotic factors and mitogen-activated protein kinase (MAPK). In addition, CS and CSE effectively decreased the serum lipid concentrations and downregulated hepatic sterol regulatory element-binding proteins expression. In conclusion, the skate CSE could protect against LPS-induced hepatic dyslipidemia, oxidative stress, inflammation, and apoptosis, probably through the regulation of MAPK signaling.

  5. Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

    Science.gov (United States)

    Sakurai, Yoshihisa; Fujita, Zenya; Ishige, Yusuke

    2016-01-01

    This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions. PMID:27049388

  6. Cardiorespiratory demands during an inline speed skating marathon race: a case report.

    Science.gov (United States)

    Stangier, Carolin; Abel, Thomas; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

    2016-09-01

    This study was designed to investigate the intensity profile during an inline speed skating marathon road race. A highly-trained male athlete (20 y, 73.4 kg, 178 cm, V̇O2 peak: 60.8 mL·kg-1·min-1) participated in a marathon road race. Oxygen uptake (V̇O2), respiratory exchange ratio (RER), heart rate (HR) and speed were measured using a portable gas analysis system with a HR monitor and GPS-Sensor integrated. The athlete´s peak V̇O2, HR and speed at ventilatory thresholds were assessed during an incremental field test (22 km·h-1, increase 2 km·h-1 every 5 min) one week before the race. During the race, the absolute time spent in the "easy intensity zone" (V̇O2 below VT1) was 1 min, 49 min "moderate intensity zone" (V̇O2 between VT1 and VT2), and 26 min in the "hard intensity zone" (V̇O2 above VT2). The average HR was 171±6 bpm, corresponding to 95% of the maximum. This study shows that inline speed skating road races over a marathon are conducted at moderate to high V̇O2 and heart rate levels. The physiological racing pattern is very intermittent, requiring both a high level of aerobic and anaerobic capacity.

  7. Optimal pacing strategy: from theoretical modelling to reality in 1500-m speed skating.

    Science.gov (United States)

    Hettinga, F J; De Koning, J J; Schmidt, L J I; Wind, N A C; Macintosh, B R; Foster, C

    2011-01-01

    Athletes are trained to choose the pace which is perceived to be correct during a specific effort, such as the 1500-m speed skating competition. The purpose of the present study was to "override" self-paced (SP) performance by instructing athletes to execute a theoretically optimal pacing profile. Seven national-level speed-skaters performed a SP 1500-m which was analysed by obtaining velocity (every 100 m) and body position (every 200 m) with video to calculate total mechanical power output. Together with gross efficiency and aerobic kinetics, obtained in separate trials, data were used to calculate aerobic and anaerobic power output profiles. An energy flow model was applied to SP, simulating a range of pacing strategies, and a theoretically optimal pacing profile was imposed in a second race (IM). Final time for IM was ∼2 s slower than SP. Total power distribution per lap differed, with a higher power over the first 300 m for IM (637.0 (49.4) vs 612.5 (50.0) W). Anaerobic parameters did not differ. The faster first lap resulted in a higher aerodynamic drag coefficient and perhaps a less effective push-off. Experienced athletes have a well-developed performance template, and changing pacing strategy towards a theoretically optimal fast start protocol had negative consequences on speed-skating technique and did not result in better performance.

  8. Motor unit firing frequency of lower limb muscles during an incremental slide board skating test.

    Science.gov (United States)

    Piucco, Tatiane; Bini, Rodrigo; Sakaguchi, Masanori; Diefenthaeler, Fernando; Stefanyshyn, Darren

    2017-11-01

    This study investigated how the combination of workload and fatigue affected the frequency components of muscle activation and possible recruitment priority of motor units during skating to exhaustion. Ten male competitive speed skaters performed an incremental maximal test on a slide board. Activation of six muscles from the right leg was recorded throughout the test. A time-frequency analysis was performed to compute overall, high, and low frequency bands from the whole signal at 10, 40, 70, and 90% of total test time. Overall activation increased for all muscles throughout the test (p  0.80). There was an increase in low frequency (90 vs. 10%, p = 0.035, ES = 1.06) and a decrease in high frequency (90 vs. 10%, p = 0.009, ES = 1.38, and 90 vs. 40%, p = 0.025, ES = 1.12) components of gluteus maximus. Strong correlations were found between the maximal cadence and vastus lateralis, gluteus maximus and gluteus medius activation at the end of the test. In conclusion, the incremental skating test lead to an increase in activation of lower limb muscles, but only gluteus maximus was sensitive to changes in frequency components, probably caused by a pronounced fatigue.

  9. Asymmetry of quadriceps muscle oxygenation during elite short-track speed skating.

    Science.gov (United States)

    Hesford, Catherine Mary; Laing, Stewart J; Cardinale, Marco; Cooper, Chris E

    2012-03-01

    It has been suggested that, because of the low sitting position in short-track speed skating, muscle blood flow is restricted, leading to decreases in tissue oxygenation. Therefore, wearable wireless-enabled near-infrared spectroscopy (NIRS) technology was used to monitor changes in quadriceps muscle blood volume and oxygenation during a 500-m race simulation in short-track speed skaters. Six elite skaters, all of Olympic standard (age = 23 ± 1.8 yr, height = 1.8 ± 0.1 m, mass = 80.1 ± 5.7 kg, midthigh skinfold thickness = 7 ± 2 mm), were studied. Subjects completed a 500-m race simulation time trial (TT). Whole-body oxygen consumption was simultaneously measured with muscle oxygenation in right and left vastus lateralis as measured by NIRS. Mean time for race completion was 44.8 ± 0.4 s. VO2 peaked 20 s into the race. In contrast, muscle tissue oxygen saturation (TSI%) decreased and plateaued after 8 s. Linear regression analysis showed that right leg TSI% remained constant throughout the rest of the TT (slope value = 0.01), whereas left leg TSI% increased steadily (slope value = 0.16), leading to a significant asymmetry (P skating has implications for training and performance.

  10. Automatic Identification of Subtechniques in Skating-Style Roller Skiing Using Inertial Sensors

    Directory of Open Access Journals (Sweden)

    Yoshihisa Sakurai

    2016-04-01

    Full Text Available This study aims to develop and validate an automated system for identifying skating-style cross-country subtechniques using inertial sensors. In the first experiment, the performance of a male cross-country skier was used to develop an automated identification system. In the second, eight male and seven female college cross-country skiers participated to validate the developed identification system. Each subject wore inertial sensors on both wrists and both roller skis, and a small video camera on a backpack. All subjects skied through a 3450 m roller ski course using a skating style at their maximum speed. The adopted subtechniques were identified by the automated method based on the data obtained from the sensors, as well as by visual observations from a video recording of the same ski run. The system correctly identified 6418 subtechniques from a total of 6768 cycles, which indicates an accuracy of 94.8%. The precisions of the automatic system for identifying the V1R, V1L, V2R, V2L, V2AR, and V2AL subtechniques were 87.6%, 87.0%, 97.5%, 97.8%, 92.1%, and 92.0%, respectively. Most incorrect identification cases occurred during a subtechnique identification that included a transition and turn event. Identification accuracy can be improved by separately identifying transition and turn events. This system could be used to evaluate each skier’s subtechniques in course conditions.

  11. Identification guide to skates (Family Rajidae) of the Canadian Atlantic and adjacent regions

    Science.gov (United States)

    Sulak, Kenneth J.; MacWhirter, P. D.; Luke, K.E.; Norem, A.D.; Miller, J.M.; Cooper, J.A.; Harris, L.E.

    2009-01-01

    Ecosystem-based management requires sound information on the distribution and abundance of species both common and rare. Therefore, the accurate identification for all marine species has assumed a much greater importance. The identification of many skate species is difficult as several are easily confused and has been found to be problematic in both survey data and fisheries data collection. Identification guides, in combination with training and periodic validation of taxonomic information, improve our accuracy in monitoring data required for ecosystem-based management and monitoring of populations. This guide offers a comparative synthesis of skate species known to occur in Atlantic Canada and adjacent regions. The taxonomic nomenclature and descriptions of key morphological features are based on the most up-to-date understanding of diversity among these species. Although this information will aid the user in accurate identification, some features vary geographically (such as colour) and others with life stage (most notably the proportion of tail length to body length; the presence of spines either sharper in juveniles or in some cases not yet present; and also increases in the number of tooth rows as species grow into maturity). Additional information on juvenile features are needed to facilitate problematic identifications (e.g. L. erinacea vs. L. ocellata). Information on size at maturity is still required for many of these species throughout their geographic distribution.

  12. Identification of a single sinusoidal bile salt uptake system in skate liver

    International Nuclear Information System (INIS)

    Fricker, G.; Hugentobler, G.; Meier, P.J.; Kurz, G.; Boyer, J.L.

    1987-01-01

    To identify the sinusoidal bile acid uptake system(s) of skate liver, photoaffinity labeling and kinetic transport studies were performed in isolated plasma membranes as well as intact hepatocytes. In both preparations photoaffinity labeling with the photolabile bile salt derivative revealed the presence of a predominant bile salt binding polypeptide with an apparent molecular weight of 54,000. The [ 3 H]-labeling of this polypeptide was inhibited by taurocholate and cholate in a concentration-dependent manner and was virtually abolished by 1 mM of the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. Kinetic studies of hepatic uptake with taurocholate, cholate, and the photoreactive bile salt derivative indicated the involvement of a single transport system, and all three substrates mutually competed with the uptake of each other. Finally, irreversible inhibition of the bile salt uptake system of photoaffinity labeling of hepatocytes with high concentrations of photolabile derivative reduced the V max but the K m of taurocholate uptake. These findings strongly indicate that a single polypeptide with an apparent molecular weight of 54,000 is involved in sinusoidal bile salt uptake into skate hepatocytes. These findings contrast with similar studies in rat liver that implicate both a 54,000- and 48,000-K polypeptide in bile salt uptake and are consistent with a single Na + -independent transport mechanism for hepatic bile salt uptake in this primitive vertebrate

  13. Conditioning Methodologies for DanceSport: Lessons from Gymnastics, Figure Skating, and Concert Dance Research.

    Science.gov (United States)

    Outevsky, David; Martin, Blake Cw

    2015-12-01

    Dancesport, the competitive branch of ballroom dancing, places high physiological and psychological demands on its practitioners, but pedagogical resources in these areas for this dance form are limited. Dancesport competitors could benefit from strategies used in other aesthetic sports. In this review, we identify conditioning methodologies from gymnastics, figure skating, and contemporary, modern, and ballet dance forms that could have relevance and suitability for dancesport training, and propose several strategies for inclusion in the current dancesport curriculum. We reviewed articles derived from Google Scholar, PubMed, ScienceDirect, Taylor & Francis Online, and Web of Science search engines and databases, with publication dates from 1979 to 2013. The keywords included MeSH terms: dancing, gymnastics, physiology, energy metabolism, physical endurance, and range of motion. Out of 47 papers examined, 41 papers met the inclusion criteria (validity of scientific methods, topic relevance, transferability to dancesport, publication date). Quality and validity of the data were assessed by examining the methodologies in each study and comparing studies on similar populations as well as across time using the PRISMA 2009 checklist and flowchart. The relevant research suggests that macro-cycle periodization planning, aerobic and anaerobic conditioning, range of motion and muscular endurance training, and performance psychology methods have potential for adaptation for dancesport training. Dancesport coaches may help their students fulfill their ambitions as competitive athletes and dance artists by adapting the relevant performance enhancement strategies from gymnastics, figure skating, and concert dance forms presented in this paper.

  14. A natural ice boom

    Energy Technology Data Exchange (ETDEWEB)

    Hopper, H.R. [Manitoba Hydro, Winnipeg, MB (Canada)

    1998-10-01

    Planning for ice jams and ice movements are critical on the Nelson River in northern Manitoba in designing cofferdams. Experience on the St. Lawrence River demonstrated the possibility of exercising some control over ice action by judicious placement of log booms or ice control structures. The success of experiments with man-made controls led to field tests in which an ice sheet of sufficient magnitude and competence was introduced into the open water stream of the Nelson River. The ice sheet was subsequently jammed in a narrow channel, thereby creating a natural ice bridge or boom upstream of a proposed hydro development. Under favourable conditions, this boom would initiate the progression of the ice cover from its location upstream, cutting off the downstream reach from the ice producing potential of the upstream reach. Although ice would still be generated downstream, the length of the reach between the ice boom and the development site would be short enough that ice jamming at the development site would never occur. Although problems in blasting prevented the introduction of a competent ice sheet into the main stream of the river at the location chosen, sufficient confidence in the theory was gained to warrant further consideration. 4 refs., 1 tab., 10 figs.

  15. The relationship between ventilatory threshold and repeated-sprint ability in competitive male ice hockey players

    Directory of Open Access Journals (Sweden)

    Matthew R. Lowery

    2018-04-01

    Full Text Available Background/objective: The relationship between ventilatory threshold (VT1, VT2 and repeated-sprint ability (RSA in competitive male ice hockey players was investigated. Methods: Forty-three male ice hockey players aged 18–23 years competing in NCAA Division I, NCAA Division III, and Junior A level participated. Participants performed an incremental graded exercise test on a skate treadmill to determine V˙O2peak, VT1, and VT2 using MedGraphics Breezesuit™ software (v-slope. Participants performed an on-ice repeated shift (RSA test consisting of 8-maximal skating bouts, lasting approximately 25 s and interspersed with 90 s of passive recovery, to determine first gate, second gate, and total sprint decrement (%dec. Pearson product-moment correlations and multiple regressions were used to assess relationships between ventilatory threshold variables (VT1, VT2, Stage at VT1, and Stage at VT2 and RSA (first gate, second gate, and total course decrement. Results: Stage at VT2 was the only variable substantially correlated with first gate (r = −0.35; P < 0.05, second gate (r = −0.58; P < 0.001 and total course decrement (r = −0.42; P < 0.05. Conclusion: The results of this study demonstrated that VT is substantially associated with RSA, and VT2 is more strongly correlated with RSA than V˙O2peak. This study suggests that longer duration high-intensity interval training at intensities that increase workrate at VT2 may lead to possible improvements in RSA. Keywords: Athletes, Aerobic capacity, Fatigue, Sprint decrement

  16. Forecast Icing Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Forecast Icing Product (FIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The FIP algorithm uses...

  17. Current Icing Product

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Current Icing Product (CIP) is an automatically-generated index suitable for depicting areas of potentially hazardous airframe icing. The CIP algorithm combines...

  18. Resistance and Spray Characteristics of a 1/13-Scale Model of the Consolidated Vultee Skate 7 Seaplane, TED No. NACA DE 338

    Science.gov (United States)

    McKann, Robert E.; Coffee, Claude W.; Arabian, Donald D.

    1949-01-01

    A model of a Consolidated Vultee Aircraft Corporation Skate 7 sea-plane:was tested in Langley tank no= 2. Resistance data, 'spray photographs, and underwater photographs,are given in this report without discussion.

  19. Take-off Stability Characteristics of a 1/13-scale Model of the Consolidated Vultee Skate 7 Seaplane (TED No. NACA DE 338)

    Science.gov (United States)

    McKann, Robert; Coffee, Claude W.; Abrabian, Donald D.

    1949-01-01

    The take-off stability characteristics of a Consolidated Vultee Aircraft Corporation Skate 7 seaplane were determined in the Langley tank no. 2. Trim limits of stability, trim tracks, and elevator limits of stability are presented.

  20. Exposure to 3,3’,4,4’,5-pentachlorobiphenyl (PCB 126) impacts multiple organ systems in developing little skate (Leucoraja erinacea).

    Science.gov (United States)

    Effects of exposure to coplanar polychlorinated biphenyls (PCBs) and other dioxin-like chemicals on developing vertebrates involve many organ systems, including the skeletal and cardiovascular systems. Apex predators, including those from the class Chondrichthyes (sharks, skates,...

  1. Sputtering of water ice

    International Nuclear Information System (INIS)

    Baragiola, R.A.; Vidal, R.A.; Svendsen, W.; Schou, J.; Shi, M.; Bahr, D.A.; Atteberrry, C.L.

    2003-01-01

    We present results of a range of experiments of sputtering of water ice together with a guide to the literature. We studied how sputtering depends on the projectile energy and fluence, ice growth temperature, irradiation temperature and external electric fields. We observed luminescence from the decay of H(2p) atoms sputtered by heavy ion impact, but not bulk ice luminescence. Radiolyzed ice does not sputter under 3.7 eV laser irradiation

  2. Study on the conditions of methanol use as a secondary refrigerant; Etude sur les conditions d'utilisation du methanol comme refrigerant secondaire

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-11-01

    This study examined the advantages and safe use of a water and methanol solution for use in a piped cooling network in skating rinks. A methanol/water solution offers simple repair solutions for leaks under ice, because unlike brine, it does not leave spots or soften the ice. The solution is less corrosive than brine and offers efficient heat transfer in heat exchangers. The standards and regulations that apply to the methanol/water solution were outlined. The following preventive measures are recommended to minimize risk associated with methanol in skating rinks: solutions should be diluted to 25 per cent methanol to avoid storing and handling of more concentrated products; methanol vapour detectors should be installed in service rooms where spills may occur; respiratory and protective eye protection should be available in service rooms; and, protection should be provided against freezing when the product is circulated outside of the arena. This study also examined the negative effects on health, including toxicity. Risks related to the environment, flammability and the physicochemical compatibility of methanol with materials were examined. The properties of the methanol/water solution were listed with reference to flash point, autoignition temperature, and the lower and upper flammable or explosive limits. tabs., figs. appendices.

  3. Helicopter Icing Review.

    Science.gov (United States)

    1980-09-01

    helicopter (i.e. in an icing tunnel or engine test cell ) and therefore can be subjected to controlled icing where spe- cific problems can be safely...evaluation. 69 2.2.5.2 Ice Protection Systems Demonstration Many of the systems noted in 2.2.5.1 can be evaluated in icing test cells or icing wind tunnels...Figure 2-32 illustrates a typical rotor deice system control arrangement. 104 (N >4 A.dO INaH -E- C4) uo U En 9 E-1 H m I ~z O 04 04iH U 0 El4 E-f C E

  4. Effects of Cycling vs. Running Training on Endurance Performance in Preparation for Inline Speed Skating.

    Science.gov (United States)

    Stangier, Carolin; Abel, Thomas; Hesse, Clemens; Claen, Stephanie; Mierau, Julia; Hollmann, Wildor; Strüder, Heiko K

    2016-06-01

    Winter weather conditions restrict regular sport-specific endurance training in inline speed skating. As a result, this study was designed to compare the effects of cycling and running training programs on inline speed skaters' endurance performance. Sixteen (8 men, 8 women) high-level athletes (mean ± SD 24 ± 8 years) were randomly assigned to 1 of 2 groups (running and cycling). Both groups trained twice a week for 8 weeks, one group on a treadmill and the other on a cycle ergometer. Training intensity and duration was individually calculated (maximal fat oxidation: ∼52% of V[Combining Dot Above]O2peak: 500 kcal per session). Before and after the training intervention, all athletes performed an incremental specific (inline speed skating) and 1 nonspecific (cycling or running) step test according to the group affiliation. In addition to blood lactate concentration, oxygen uptake (V[Combining Dot Above]O2), ventilatory equivalent (VE/V[Combining Dot Above]O2), respiratory exchange ratio (RER), and heart rate were measured. The specific posttest revealed significantly increased absolute V[Combining Dot Above]O2peak values (2.9 ± 0.4, 3.4 ± 0.7, p = 0.01) and submaximal V[Combining Dot Above]O2 values (p ≤ 0.01). VE/V[Combining Dot Above]O2 and RER significantly decreased at maximal (46.6 ± 6.6, 38.5 ± 3.4, p = 0.005; 1.1 ± 0.03, 1.0 ± 0.04, p = 0.001) and submaximal intensities (p ≤ 0.04). None of the analysis revealed a significant group effect (p ≥ 0.15). The results indicate that both cycling vs. running exercise at ∼52% of V[Combining Dot Above]O2peak had a positive effect on the athletes' endurance performance. The increased submaximal V[Combining Dot Above]O2 values indicate a reduction in athletes' inline speed skating technique. Therefore, athletes would benefit from a focus on technique training in the subsequent period.

  5. Ice slurry applications

    Energy Technology Data Exchange (ETDEWEB)

    Kauffeld, M. [Karlsruhe University of Applied Sciences, Moltkestr. 30, 76133 Karlsruhe (Germany); Wang, M.J.; Goldstein, V. [Sunwell Technologies Inc., 180 Caster Avenue, Woodbridge, L4L 5Y (Canada); Kasza, K.E. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2010-12-15

    The role of secondary refrigerants is expected to grow as the focus on the reduction of greenhouse gas emissions increases. The effectiveness of secondary refrigerants can be improved when phase changing media are introduced in place of single-phase media. Operating at temperatures below the freezing point of water, ice slurry facilitates several efficiency improvements such as reductions in pumping energy consumption as well as lowering the required temperature difference in heat exchangers due to the beneficial thermo-physical properties of ice slurry. Research has shown that ice slurry can be engineered to have ideal ice particle characteristics so that it can be easily stored in tanks without agglomeration and then be extractable for pumping at very high ice fraction without plugging. In addition ice slurry can be used in many direct contact food and medical protective cooling applications. This paper provides an overview of the latest developments in ice slurry technology. (author)

  6. Autonomous Aerial Ice Observation for Ice Defense

    Directory of Open Access Journals (Sweden)

    Joakim Haugen

    2014-10-01

    Full Text Available One of the tasks in ice defense is to gather information about the surrounding ice environment using various sensor platforms. In this manuscript we identify two monitoring tasks known in literature, namely dynamic coverage and target tracking, and motivate how these tasks are relevant in ice defense using RPAS. An optimization-based path planning concept is outlined for solving these tasks. A path planner for the target tracking problem is elaborated in more detail and a hybrid experiment, which consists of both a real fixed-wing aircraft and simulated objects, is included to show the applicability of the proposed framework.

  7. Arctic landfast sea ice

    Science.gov (United States)

    Konig, Christof S.

    Landfast ice is sea ice which forms and remains fixed along a coast, where it is attached either to the shore, or held between shoals or grounded icebergs. Landfast ice fundamentally modifies the momentum exchange between atmosphere and ocean, as compared to pack ice. It thus affects the heat and freshwater exchange between air and ocean and impacts on the location of ocean upwelling and downwelling zones. Further, the landfast ice edge is essential for numerous Arctic mammals and Inupiat who depend on them for their subsistence. The current generation of sea ice models is not capable of reproducing certain aspects of landfast ice formation, maintenance, and disintegration even when the spatial resolution would be sufficient to resolve such features. In my work I develop a new ice model that permits the existence of landfast sea ice even in the presence of offshore winds, as is observed in mature. Based on viscous-plastic as well as elastic-viscous-plastic ice dynamics I add tensile strength to the ice rheology and re-derive the equations as well as numerical methods to solve them. Through numerical experiments on simplified domains, the effects of those changes are demonstrated. It is found that the modifications enable landfast ice modeling, as desired. The elastic-viscous-plastic rheology leads to initial velocity fluctuations within the landfast ice that weaken the ice sheet and break it up much faster than theoretically predicted. Solving the viscous-plastic rheology using an implicit numerical method avoids those waves and comes much closer to theoretical predictions. Improvements in landfast ice modeling can only verified in comparison to observed data. I have extracted landfast sea ice data of several decades from several sources to create a landfast sea ice climatology that can be used for that purpose. Statistical analysis of the data shows several factors that significantly influence landfast ice distribution: distance from the coastline, ocean depth, as

  8. Differences in muscle oxygenation, perceived fatigue and recovery between long-track and short-track speed skating

    Directory of Open Access Journals (Sweden)

    Florentina Johanna Hettinga

    2016-12-01

    Full Text Available Due to the technical nature of speed skating, that is affecting physiological mechanisms such as oxygenation and blood flow, this sport provides a unique setting allowing us to uncover novel mechanistic insights of the physiological response to exercise in elite middle-distance and endurance sports. The present study aimed to examine the influence of skating mode (short-track vs. long-track on muscle oxygenation, perceived fatigue, and recovery in elite speed skating. Muscle oxygenation of twelve talented short-track speed skaters was continuously monitored during a long-track (LT and a short-track (ST skating time-trials of maximal effort using near-infrared spectroscopy (NIRS on the m. vastus lateralis for both legs. Video captures were made of each testing session for further interpretation of the muscle oxygenation. To determine recovery, perceived exertion was measured two and four hours after each testing sessions. Repeated measures ANOVA’s were used for statistical analysis (p<.05. After a rapid desaturation in both legs directly after the start, an asymmetry in muscle oxygenation between both legs was found during LT (tissue saturation-index (TSI%-slope: left=0.053±0.032; right=0.023±0.020, p<.05 and ST speed skating (TSI%-slope: left=0.050±0,052, right=0.001 ±0.053, p<.05. Re-Resaturation of the right leg was relatively lower in ST compared to LT. For the left leg, no difference was found between skating modes in muscle oxygenation. Respectively, two (ST=5.8±2.0; LT=4.2±1.5 and four hours (ST=4.6±1.9; LT=3.1±1.6 after the time-trials, a higher rate of perceived exertion was found for ST. Based on our results, ST seems more physiologically demanding, and longer periods of recovery are needed after training compared to LT. Technical aspects unique to the exercise mode seem to impact on oxygenation, affecting processes related to the regulation of exercise intensity such as fatigue and recovery.

  9. Reproductive biology of the Alaska skate Bathyraja parmifera, with comments on an intersexual individual.

    Science.gov (United States)

    Matta, M E

    2015-09-01

    A total of 1357 specimens of Alaska skate Bathyraja parmifera were collected in the eastern Bering Sea by fisheries observers and during scientific groundfish surveys from 2003 to 2005. Male and female gonads were examined for maturity stage and seasonal reproductive timing. Based on seasonal reproductive data, including the occurrence of egg cases, ovum size, ovum number, shell-gland width and gonado-somatic index, this species appears to reproduce continually throughout the year. Potential effects of maternal size upon the size and number of mature oocytes were also investigated, with total length having a significant, although weak, influence on both. Morphology of a single intersexual individual encountered during the collection period is also described. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

  10. Dipturus amphispinus sp. nov., a new longsnout skate (Rajoidei: Rajidae) from the Philippines.

    Science.gov (United States)

    Last, Peter R; Alava, Moonyeen

    2013-01-01

    A new long-snouted skate, Dipturus amphispinus sp. nov., is formally described based on material caught in the Sulu Sea and later acquired from fish markets of the central and southern Philippines. It differs from its congeners in the western North Pacific, apart from D. wuhanlingi (East and South China Seas), in having a variably-defined, parallel row of posterolaterally directed lumbar thorns, and well-developed scapular thorns on each side of the disc. However, the paired rows of lumbar thorns are better defined in Dipturus amphispinus sp. nov. than in D. wuhanlingi, and these species also differ in some aspects of their morphometrics, meristics and squamation. Dipturus amphispinus sp. nov. displays marked sexual dimorphism with adult males having a relatively broader mouth, much longer teeth, a relatively shorter snout, head and disc, a taller first dorsal fin, and a proportionally longer posterior pelvic-fin lobe and tail, than adult-sized females.

  11. O que o skate pode dizer sobre o ensino de geografia?

    Directory of Open Access Journals (Sweden)

    Luciano Hermes da Silva

    2014-07-01

    Full Text Available Este artigo pretende problematizar a prática do skate de rua como objeto de reflexão no âmbito do ensino de Geografia. Objetiva demonstrar como os skatistas protagonizam a ressignificação da cidade através de usos originais do mobiliário urbano. Trata-se de reforçar o movimento que articula as práticas espaciais dos jovens aos conteúdos e temas tradicionais da Geografia. A partir da referência ao conceito de espaço público, busca-se demonstrar que o recurso às práticas cotidianas da juventude permite problematizar conflitos, relações identitárias e processos relacionados à produção social do espaço.

  12. Skating on a Film of Air: Drops Impacting on a Surface

    Science.gov (United States)

    Kolinski, John M.; Rubinstein, Shmuel M.; Mandre, Shreyas; Brenner, Michael P.; Weitz, David A.; Mahadevan, L.

    2012-02-01

    The commonly accepted description of drops impacting on a surface typically ignores the essential role of the air that is trapped between the impacting drop and the surface. Here we describe a new imaging modality that is sensitive to the behavior right at the surface. We show that a very thin film of air, only a few tens of nanometers thick, remains trapped between the falling drop and the surface as the drop spreads. The thin film of air serves to lubricate the drop enabling the fluid to skate on the air film laterally outward at surprisingly high velocities, consistent with theoretical predictions. Eventually this thin film of air breaks down as the fluid wets the surface via a spinodal-like mechanism. Our results show that the dynamics of impacting drops are much more complex than previously thought, with a rich array of unexpected phenomena that require rethinking classic paradigms.

  13. Polarizability of KC60: Evidence for Potassium Skating on the C60 Surface

    Science.gov (United States)

    Rayane, D.; Antoine, R.; Dugourd, Ph.; Benichou, E.; Allouche, A. R.; Aubert-Frécon, M.; Broyer, M.

    2000-02-01

    We present the first measurement of the polarizability and the permanent dipole moment of isolated KC60 molecules by molecular beam deflection technique. We have obtained a value of 2506+/-250 Å3 for the polarizability at room temperature. The addition of a potassium atom enhances by more than a factor of 20 the polarizability of a pure C60 molecule. This very high polarizability and the lack of observed permanent dipole show that the apparent polarizability of KC60 is induced by the free skating of the potassium atom on the C60 surface, resulting in a statistical orientation of the dipole. The results are interpreted with a simple model similar to the Langevin theory for paramagnetic systems.

  14. Engineering movement of qualified skiers-racers skating style in the current development of ski races

    Directory of Open Access Journals (Sweden)

    Sergey Kotliar

    2015-08-01

    Full Text Available Purpose: analysis of technique of skiing skating style of leading sportsmen of the world. Material and Methods: research was conducted by means of analysis of video data and кинограмм of of skilled racing cross-country ski and biathlon of leading countries of the world. Results: the analysis of dynamic descriptions of technique of the same name ski motions educed the row of factors, from that sportsmen, what applied «Double Push» in the technique of skiing, increase speed of passing of short segments on 4-6%. Conclusions: implementation of «Double Push» can useful for racing cross-country ski and biathlon on competitions on a sprint, on rollers-ski and at implementation of short accelerations on distance, and also on a finish

  15. Energy pumping analysis of skating motion in a half pipe and on a level surface

    Science.gov (United States)

    Feng, Z. C.; Xin, Ming

    2015-01-01

    In this paper, an energy pumping mechanism for locomotion is analysed. The pumping is accomplished by exerting forces perpendicular to the direction of motion. The paper attempts to demonstrate an interesting application of the classical mechanics to two sporting events: a person skating in a half pipe and a person travelling on a level surface on a skateboard. The equations of motion based on simplified mechanical models are derived using the Lagrange mechanics. The energy-pumping phenomenon is revealed through numerical simulations with simple pumping actions. The result presented in this paper can be used as an interesting class project in undergraduate mechanics or physics courses. It also motivates potential new applications of energy pumping in many engineering fields.

  16. Energy pumping analysis of skating motion in a half pipe and on a level surface

    International Nuclear Information System (INIS)

    Feng, Z C; Xin, Ming

    2015-01-01

    In this paper, an energy pumping mechanism for locomotion is analysed. The pumping is accomplished by exerting forces perpendicular to the direction of motion. The paper attempts to demonstrate an interesting application of the classical mechanics to two sporting events: a person skating in a half pipe and a person travelling on a level surface on a skateboard. The equations of motion based on simplified mechanical models are derived using the Lagrange mechanics. The energy-pumping phenomenon is revealed through numerical simulations with simple pumping actions. The result presented in this paper can be used as an interesting class project in undergraduate mechanics or physics courses. It also motivates potential new applications of energy pumping in many engineering fields. (paper)

  17. Removable cruciform for ice condenser ice basket

    International Nuclear Information System (INIS)

    Scrabis, C.M.; Mazza, G.E.; Golick, L.R.; Pomaibo, P.

    1987-01-01

    A removable cruciform for use in an ice basket having a generally cylindrical sidewall defining a central, vertical axis of the ice basket and plural, generally annular retaining rings secured to the interior of the cylindrical sidewall of the ice basket at predetermined, spaced elevations throughout the axial height of the ice basket is described comprising: a pair of brackets, each comprising a central, base portion having parallel longitudinal edges and a pair of integral legs extending at corresponding angles relative to the base portion from the perspective parallel longitudinal edges thereof; a pair of support plate assemblies secured to and extending in parallel, spaced relationship from one of the pair of brackets; a pair of slide support plates secured to the other of the pair of brackets and extending therefrom in spaced, parallel relationship; and spring means received within the housing and engaging the base portions of the brackets and applying a resilient biasing force thereto for maintaining the spaced relationship thereof

  18. Ice cream structure modification by ice-binding proteins.

    Science.gov (United States)

    Kaleda, Aleksei; Tsanev, Robert; Klesment, Tiina; Vilu, Raivo; Laos, Katrin

    2018-04-25

    Ice-binding proteins (IBPs), also known as antifreeze proteins, were added to ice cream to investigate their effect on structure and texture. Ice recrystallization inhibition was assessed in the ice cream mixes using a novel accelerated microscope assay and the ice cream microstructure was studied using an ice crystal dispersion method. It was found that adding recombinantly produced fish type III IBPs at a concentration 3 mg·L -1 made ice cream hard and crystalline with improved shape preservation during melting. Ice creams made with IBPs (both from winter rye, and type III IBP) had aggregates of ice crystals that entrapped pockets of the ice cream mixture in a rigid network. Larger individual ice crystals and no entrapment in control ice creams was observed. Based on these results a model of ice crystals aggregates formation in the presence of IBPs was proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. The feeding habits of the eyespot skate Atlantoraja cyclophora (Elasmobranchii: Rajiformes in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Alessandra da Fonseca Viana

    2014-04-01

    Full Text Available The stomach contents of the eyespot skate, Atlantoraja cyclophora (Regan, 1903, were examined with the goal to provide information about the diet of the species. Samples were collected off the southern coast of Rio de Janeiro, Brazil, near Ilha Grande, between January 2006 and August 2007, at a depth of about 60 m. The diet was analyzed by sex, maturity stages and quarterly to verify differences in the importance of food items. The latter were analyzed by: frequency of occurrence, percentage of weight and in the Alimentary Index. The trophic niche width was determined to assess the degree of specialization in the diet. Additionally, the degree of dietary overlap between males and females; juveniles and adults and periods of the year were defined. A total of 59 individuals of A. cyclophora were captured. Females and adults were more abundant. The quarters with the highest concentrations of individuals were in the summer of the Southern Hemisphere: Jan-Feb-Mar 06 and Jan-Feb-Mar 07. Prey items were classed into five main groups: Crustacea, Teleosts, Elasmobranchs, Polychaeta, and Nematoda. The most important groups in the diet of the eyespot skate were Crustacea and Teleosts. The crab Achelous spinicarpus (Stimpson, 1871 was the most important item. The value of the niche width was small, indicating that a few food items are important. The comparison of the diet between males and females and juveniles and adults indicates a significant overlap between the sexes and stages of maturity; and according to quarters, the importance of prey groups differed (crustaceans were more important in the quarters of the summer and teleost in Jul-Aug-Sep and Oct-Nov-Dec 06, indicating seasonal differences in diet composition. Three groups with similar diets were formed in the cluster analysis: (Jan-Feb-Mar 06 and 07; (Apr-May-Jun 06 and Jul-Aug-Sep 07; (Jul-Aug-Sep 06 and Oct-Nov-Dec 06.

  20. Two novel antioxidant nonapeptides from protein hydrolysate of skate (Raja porosa) muscle.

    Science.gov (United States)

    Hu, Fa-Yuan; Chi, Chang-Feng; Wang, Bin; Deng, Shang-Gui

    2015-04-03

    In the current study, the preparation conditions of neutrase hydrolysate (SMH) from skate (Raja porosa) muscle protein were optimized using orthogonal L9(3)4 tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S) 2%, and enzymolysis time 5 h, EC50 of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B) were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A) and NWDMEKIWD (SP-B) with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC50 0.390 and 0.176 mg/mL), DPPH· (EC50 0.614 and 0.289 mg/mL), and O2-· (EC50 0.215 and 0.132 mg/mL) in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp), acidic (2Asp and Glu), and basic (Lys) amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.

  1. Two Novel Antioxidant Nonapeptides from Protein Hydrolysate of Skate (Raja porosa Muscle

    Directory of Open Access Journals (Sweden)

    Fa-Yuan Hu

    2015-04-01

    Full Text Available In the current study, the preparation conditions of neutrase hydrolysate (SMH from skate (Raja porosa muscle protein were optimized using orthogonal L9(34 tests, and R values indicated that pH was the most important factor affecting HO· scavenging activity of SMH. Under the optimum conditions of pH 7.0, enzymolysis temperature 60 °C, enzyme/substrate ratio (E/S 2%, and enzymolysis time 5 h, EC50 of SMH on HO· was 2.14 ± 0.17 mg/mL. Using ultrafiltration, gel filtration chromatography, and RP-HPLC, two novel antioxidant nonapeptides (SP-A and SP-B were isolated from SMH and their amino acid sequences were found to be APPTAYAQS (SP-A and NWDMEKIWD (SP-B with calculated molecular masses of 904.98 Da and 1236.38 Da, respectively. Both showed strong antioxidant activities. SP-A and SP-B exhibited good scavenging activities on HO· (EC50 0.390 and 0.176 mg/mL, DPPH· (EC50 0.614 and 0.289 mg/mL, and O2−· (EC50 0.215 and 0.132 mg/mL in a dose-dependent manner. SP-B was also effective against lipid peroxidation in the model system. The aromatic (2Trp, acidic (2Asp and Glu, and basic (Lys amino acid residues within the sequences of SP-B might account for its pronounced antioxidant activity. The results of this study suggested that protein hydrolysate and peptides from skate muscle might be effective as food additives for retarding lipid peroxidation occurring in foodstuffs.

  2. Pacing Strategy, Muscle Fatigue, and Technique in 1500-m Speed-Skating and Cycling Time Trials.

    Science.gov (United States)

    Stoter, Inge K; MacIntosh, Brian R; Fletcher, Jared R; Pootz, Spencer; Zijdewind, Inge; Hettinga, Florentina J

    2016-04-01

    To evaluate pacing behavior and peripheral and central contributions to muscle fatigue in 1500-m speed-skating and cycling time trials when a faster or slower start is instructed. Nine speed skaters and 9 cyclists, all competing at regional or national level, performed two 1500-m time trials in their sport. Athletes were instructed to start faster than usual in 1 trial and slower in the other. Mean velocity was measured per 100 m. Blood lactate concentrations were measured. Maximal voluntary contraction (MVC), voluntary activation (VA), and potentiated twitch (PT) of the quadriceps muscles were measured to estimate central and peripheral contributions to muscle fatigue. In speed skating, knee, hip, and trunk angles were measured to evaluate technique. Cyclists showed a more explosive start than speed skaters in the fast-start time trial (cyclists performed first 300 m in 24.70 ± 1.73 s, speed skaters in 26.18 ± 0.79 s). Both trials resulted in reduced MVC (12.0% ± 14.5%), VA (2.4% ± 5.0%), and PT (25.4% ± 15.2%). Blood lactate concentrations after the time trial and the decrease in PT were greater in the fast-start than in the slow-start trial. Speed skaters showed higher trunk angles in the fast-start than in the slow-start trial, while knee angles remained similar. Despite similar instructions, behavioral adaptations in pacing differed between the 2 sports, resulting in equal central and peripheral contributions to muscle fatigue in both sports. This provides evidence for the importance of neurophysiological aspects in the regulation of pacing. It also stresses the notion that optimal pacing needs to be studied sport specifically, and coaches should be aware of this.

  3. Food habits of the broad nose skate, Bathyraja brachyurops (Chondrichthyes, Rajidae, in the south-west Atlantic

    Directory of Open Access Journals (Sweden)

    Mauro Belleggia

    2008-12-01

    Full Text Available Food habits of Bathyraja brachyurops were studied based on stomach content analyses of 346 specimens collected from research cruises carried out from 2003 to 2005 on the Argentinean continental shelf (36ºS-55ºS. A total of 265 stomachs (76.6% contained food, and thirty-five taxonomic levels of prey were identified. The most important prey were fishes followed by isopods. Trophic level analysis revealed that B. brachyurops is a tertiary consumer throughout its life history. There were no differences between sexes and regions in the diet composition, but dietary shifts with ontogeny were found. The Levins’ standardized index indicated wider niche breadth for small skates, whereas larger skate specimens showed a narrow niche breadth with a specialization in fishes.

  4. Feeding ecology of Bathyraja macloviana (Rajiformes, Arhynchobatidae: a polychaete-feeding skate from the South-west Atlantic

    Directory of Open Access Journals (Sweden)

    Ezequiel Mabragaña

    2005-09-01

    Full Text Available The present paper analyses the diet, feeding strategy and niche width of B. macloviana in a sector of the Argentinean Continental Shelf (ACS. Individuals (n = 147 were collected from 43 sampling stations in late summer and autumn 2001. Thirty one alimentary items in the gut contents were found, with a clear dominance of polychaetes. Crustaceans were secondary alimentary items. The polychaete Travisia kerguelensis was the main food item ingested, followed by Nepthyidae, Sabellidae and Lumbrineridae, while Gammaridae and Cirolanidae were the main items among crustaceans. The niche width and feeding strategy displayed by B. macloviana support the specialisation towards polychaetes throughout this study. Slow motile and infaunal species constitute major preys. The results suggest that this skate actively selects worms, reflecting, in some sense, the composition of the polychaete assemblage, and allowing a low dietary overlap with other sympatric skates of the ACS.

  5. Relationship between gene polymorphisms and development of physical qualities in athletes (based on the material of speed skating

    Directory of Open Access Journals (Sweden)

    Анна Ильютик

    2017-09-01

    Full Text Available The paper summarizes the results of the studies on the identification of the relationship between the polymorphisms in a number of genes with the manifestation of speed-strength qualities and endurance in speed skaters. The theoretical and experimental substantiation is presented for the algorithm of determining the sports specialization of athletes specializing in speed skating on the basis of the results of polymorphism analysis of the genes ACE, NOS3, BDKRB2, ACTN3, PPARG, and CYP17A1. The algorithm consists of determining both the polymorphism of individual genes and the combinations of gene polymorphisms, thus making it possible to estimate the number of alleles and genotypes associated with endurance and/or speed-strength qualities. The use of this algorithm enables identifying physical qualities, to the development of which there is the greatest genetic predisposition, and choosing on their basis a skating specialization of the athlete.

  6. Morphological Characters of the Thickbody Skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with Notes on Its Biology

    Science.gov (United States)

    Bustamante, Carlos; Lamilla, Julio; Concha, Francisco; Ebert, David A.; Bennett, Michael B.

    2012-01-01

    Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries. PMID:22768186

  7. Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968) (Rajiformes: Rajidae), with notes on its biology.

    Science.gov (United States)

    Bustamante, Carlos; Lamilla, Julio; Concha, Francisco; Ebert, David A; Bennett, Michael B

    2012-01-01

    Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries.

  8. "Extreme" or tariff sports: their injuries and their prevention (with particular reference to diving, cheerleading, gymnastics, and figure skating).

    Science.gov (United States)

    Foley, E C; Bird, H A

    2013-04-01

    The interface between sports medicine and performing arts medicine is closest for "tariff" sports, where the sportsperson can select their own programme of varying difficulty with the more complex skills carrying potential for higher marks. Inevitably, some performers over-reach themselves. Examples of injuries and prevention strategies to avoid such injuries are discussed in a preliminary analysis of four sports: diving, cheerleading, gymnastics, and figure skating.

  9. The role of incline, performance level, and gender on the gross mechanical efficiency of roller ski skating

    Science.gov (United States)

    Sandbakk, Øyvind; Hegge, Ann Magdalen; Ettema, Gertjan

    2013-01-01

    The ability to efficiently utilize metabolic energy to produce work is a key factor for endurance performance. The present study investigated the effects of incline, performance level, and gender on the gross mechanical efficiency during roller ski skating. Thirty-one male and nineteen female elite cross-country skiers performed a 5-min submaximal session at approximately 75% of VO2peak on a 5% inclined treadmill using the G3 skating technique. Thereafter, a 5-min session on a 12% incline using the G2 skating technique was performed at a similar work rate. Gross efficiency was calculated as the external work rate against rolling friction and gravity divided by the metabolic rate using gas exchange. Performance level was determined by the amount of skating FIS points [the Federation of International Skiing (FIS) approved scoring system for ski racing] where fewer points indicate a higher performance level. Strong significant correlations between work rate and metabolic rate within both inclines and gender were revealed (r = −0.89 to 0.98 and P < 0.05 in all cases). Gross efficiency was higher at the steeper incline, both for men (17.1 ± 0.4 vs. 15.8 ± 0.5%, P < 0.05) and women (16.9 ± 0.5 vs. 15.7 ± 0.4%, P < 0.05), but without any gender differences being apparent. Significant correlations between gross efficiency and performance level were found for both inclines and genders (r = −0.65 to 0.81 and P < 0.05 in all cases). The current study demonstrated that cross-country skiers of both genders used less metabolic energy to perform the same amount of work at steeper inclines, and that the better ranked elite male and female skiers skied more efficiently. PMID:24155722

  10. THE ROLE OF AEROBIC CAPACITY IN HIGH-INTENSITY INTERMITTENT EFFORTS IN ICE-HOCKEY

    Directory of Open Access Journals (Sweden)

    A. Stanula

    2014-08-01

    Full Text Available The primary objective of this study was to determine a relationship between aerobic capacity ( ·VO2max and fatigue from high-intensity skating in elite male hockey players. The subjects were twenty-four male members of the senior national ice hockey team of Poland who played the position of forward or defence. Each subject completed an on-ice Repeated-Skate Sprint test (RSS consisting of 6 timed 89-m sprints, with 30 s of rest between subsequent efforts, and an incremental test on a cycle ergometer in the laboratory, the aim of which was to establish their maximal oxygen uptake ( ·VO2max. The analysis of variance showed that each next repetition in the 6x89 m test was significantly longer than the previous one (F5,138=53.33, p<0.001. An analysis of the fatigue index (FI calculated from the times recorded for subsequent repetitions showed that the value of the FI increased with subsequent repetitions, reaching its maximum between repetitions 5 and 6 (3.10±1.16%. The total FI was 13.77±1.74%. The coefficient of correlation between ·VO2max and the total FI for 6 sprints on the distance of 89 m (r =–0.584 was significant (p=0.003. The variance in the index of players’ fatigue in the 6x89 m test accounted for 34% of the variance in ·VO2max. The 6x89 m test proposed in this study offers a high test-retest correlation coefficient (r=0.78. Even though the test is criticized for being too exhaustive and thereby for producing highly variable results it still seems that it was well selected for repeated sprint ability testing in hockey players.

  11. Aircraft Icing Handbook. (Update)

    Science.gov (United States)

    1993-01-01

    Report 1946-1947, U. S. Air Material Command Tech. Rept. 5676. Findeisen , W., *Meteorological Commentary of D (air) 1209, Icing,* Germany, Reichsamt fur...Wetterdienst, Forschungs-und Krfahrungsberichte, Ser. a, No. 29, 1943. Findeisen , W., *Meteorological-Physical Limitations of Icing on the Atmosphere...Apparatus for Measurement,’ Harvard - Mt. Washington Icing Research Report 1946-1947, U. S. Air Material Command Tech. Rept. 5676.. Findeisen , W., "The

  12. Safe Loads on Ice Sheets (Ice Engineering. Number 13)

    National Research Council Canada - National Science Library

    Haynes, F. D; Carey, Kevin L; Cattabriga, Gioia

    1996-01-01

    Every winter, ice sheets that grow on lakes and rivers in northern states are used for ice roads, ice bridges, construction platforms, airstrips, and recreational activities, It becomes very important...

  13. Seasonal variations in the physiological stress response to discrete bouts of aerial exposure in the little skate, Leucoraja erinacea.

    Science.gov (United States)

    Cicia, Angela M; Schlenker, Lela S; Sulikowski, James A; Mandelman, John W

    2012-06-01

    Aerial exposure and acute thermal stress have been shown to elicit profound physiological disruptions in obligate water-breathing teleosts. However, no study has investigated these responses in an elasmobranch. To address this, venous blood samples were collected and evaluated from little skates (Leucoraja erinacea) subjected to discrete aerial exposure durations (0, 15, and 50 min) coupled with differing abrupt thermal changes (gradient between seawater and air; winter: ΔT=-3 °C; summer: ΔT=+9 °C) in two distinct laboratory studies. In general, blood acid-base properties (e.g. decline in pH; elevation in PCO(2)) and select metabolites (elevated whole-blood lactate) and electrolytes (elevated plasma K(+)) were significantly disrupted by aerial exposure, and were most disturbed after skates were exposed to air for 50 min. However, the magnitude of the blood acid-base perturbations, metabolic contribution to the resulting blood acidosis, elevations to ionic and metabolic parameters, and delayed mortality were more extreme during the summer study, suggesting that acute thermal stress exacerbates the physiological impairments associated with aerial exposure in little skates. Conversely, a reduced thermal gradient (from seawater to air) may attenuate the magnitude of metabolic and ionic perturbations, resulting in a high physiological threshold for coping with extended aerial exposure. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Effects of basic fibroblast growth factor and insulin-like growth factor on cultured cartilage cells from skate Raja porasa

    Science.gov (United States)

    Fan, Tingjun; Jin, Lingyun; Wang, Xiaofeng

    2003-12-01

    Effects of basic fibroblast growth factor (bFGF) and insulin-like growth factor II (IGF-II) on cartilage cells from proboscis of skate, Raja porasa Günther, were investigated in this study. The cartilage cells were cultured in 20% FBS-supplemented MEM medium at 24°C. Twelve hours after culture initiation, the cartilage cells were treated with bFGF and IGF-II at different concentration combinations. It was found that 20 ng/ml of bFGF or 80 ng/ml of IGF-II was enough to have obvious stimulating effect on the growth and division of skate cartilage cells. Test of bFGF and IGF-II together, revealed that 20 ng/ml of bFGF and 80 ng/ml of IGF-II together had the best stimulating effect on the growth and division of skate cartilage cells. The cartilage cells cultured could form a monolayer at day 7.

  15. Common skate (Raja kenojei) secretes pentraxin into the cutaneous secretion: The first skin mucus lectin in cartilaginous fish.

    Science.gov (United States)

    Tsutsui, Shigeyuki; Yamaguchi, Motoki; Hirasawa, Ai; Nakamura, Osamu; Watanabe, Tasuku

    2009-08-01

    A lactose-specific lectin with a molecular mass of about 25 kDa was purified from the skin mucus of a cartilaginous fish-the common skate (Raja kenojei). The complementary DNA sequence of the lectin was 1540 bp long and contained a reading frame encoding 226 amino acids, which showed approximately 38% identity to pentraxins of mammals and teleosts. Gene expression was observed in the skin, gill, stomach and intestine in the healthy skate. We also identified an isotype gene from the liver whose deduced amino-acid sequence shared 69.0% identity with the skin type gene. The antiserum detected protein in the skin, where the lectin is localized in the epidermal cells, and in the blood plasma. The lectin genes are multicopied in the common skate genome. Although pentraxins are acute phase proteins, mRNAs of both the isotypes were not upregulated after the in vivo challenge with formalin-killed Escherichia coli, which suggests that they are constantly present in the skin mucus and blood plasma to protect against pathogenic invasion. This lectin is the fifth type of lectin found in the cutaneous secretions of fish, demonstrating that skin mucus lectins have evolved with marked molecular diversity in fish.

  16. A new species of velvet skate, Notoraja sereti n.sp. (Rajiformes: Arhynchobatidae) from Papua New Guinea.

    Science.gov (United States)

    White, William T; Last, Peter R; Mana, Ralph R

    2017-03-19

    A new arhynchobatin skate, Notoraja sereti n. sp., is described based on three specimens collected from off Madang (Papua New Guinea) at depths of 800-980 m. This medium-size Notoraja skate shares with other velcro skates from the Western Pacific, N. alisae, N. fijiensis, N. inusitata and N. longiventralis, a ventral surface covering of fine denticles giving the skin a velvety feel. Notoraja sereti differs from all of these species in having a shorter snout (preorbital length 10.1-11.1 vs. 11.5-14.5% TL, prenasal length 8.2-8.9 vs, 9.8-12.1% TL), shorter head (dorsal head length 15.2-16.2 vs. 17.1-19.3% TL, ventral head length 21.6-22.9 vs. 22.9-25.9% TL), fewer pectoral-fin radials (total radials 58-60 vs. 61-74), and fewer vertebrae (predorsal diplospondylous centra 66-71 vs. 72-82, predorsal centra 90-95 vs. 98-107, total centra 126-131 vs. 135-152).

  17. An Analysis of US Emergency Department Visits From Falls From Skiing, Snowboarding, Skateboarding, Roller-Skating, and Using Nonmotorized Scooters.

    Science.gov (United States)

    Nathanson, Brian H; Ribeiro, Kara; Henneman, Philip L

    2016-07-01

    We analyzed the US incidence of emergency department (ED) visits and hospitalizations for falls from skiing, snowboarding, skateboarding, roller-skating, and nonmotorized scooters in 2011. The outcome was hospital admission from the ED. The primary analysis compared pediatric patients aged 1 to 17 years to adults aged 18 to 44 years. The analysis used ICD-9 E-codes E885.0 to E885.4 using discharge data from the Nationwide Emergency Department Sample, Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality. Approximately 214 000 ED visits met study criteria. Skiing injuries had the highest percentage of hospitalizations (3.30% in pediatric patients and 6.65% in adults 18-44 years old). Skateboard and snowboard injuries were more likely to require hospitalization than roller skating injuries in pediatric patients (odds ratio = 2.42; 95% CI = 2.14-2.75 and odds ratio = 1.83; 95% CI =1.55-2.15, respectively). In contrast, skateboard and snowboard injuries were less severe than roller-skating injuries in adults. © The Author(s) 2015.

  18. Molecular markers reveal spatially segregated cryptic species in a critically endangered fish, the common skate (Dipturus batis).

    Science.gov (United States)

    Griffiths, Andrew M; Sims, David W; Cotterell, Stephen P; El Nagar, Aliya; Ellis, Jim R; Lynghammar, Arve; McHugh, Matthew; Neat, Francis C; Pade, Nicolas G; Queiroz, Nuno; Serra-Pereira, Bárbara; Rapp, Toby; Wearmouth, Victoria J; Genner, Martin J

    2010-05-22

    Many sharks and skates are particularly vulnerable to overfishing because of their large size, slow growth, late maturity and low fecundity. In Europe dramatic population declines have taken place in common skate (Dipturus batis L.), one of the largest demersal fish in regional shelf seas, leading to extirpations from substantial parts of its former range. Here we report the discovery of cryptic species in common skate collected from the northeast Atlantic continental shelf. Data from nuclear microsatellite markers indicated two clearly distinct clades and phylogenetic analysis of mitochondrial DNA sequences demonstrated monophyly of each one of them. Capture locations showed evidence of strong spatial segregation, with one taxon occurring mainly in waters off the southern British Isles and around Rockall, while the other was restricted to more northerly shelf waters. These apparently cryptic species showed overlapping substrate and depth preferences, but distributional limits were closely related to temperature gradients, potentially indicating thermal limits to their distributions. This discovery of hidden diversity within a large, critically endangered marine vertebrate demonstrates how marine biodiversity can be underestimated, even in such a relatively well-studied and heavily exploited region.

  19. Molecular markers reveal spatially segregated cryptic species in a critically endangered fish, the common skate (Dipturus batis)

    Science.gov (United States)

    Griffiths, Andrew M.; Sims, David W.; Cotterell, Stephen P.; El Nagar, Aliya; Ellis, Jim R.; Lynghammar, Arve; McHugh, Matthew; Neat, Francis C.; Pade, Nicolas G.; Queiroz, Nuno; Serra-Pereira, Bárbara; Rapp, Toby; Wearmouth, Victoria J.; Genner, Martin J.

    2010-01-01

    Many sharks and skates are particularly vulnerable to overfishing because of their large size, slow growth, late maturity and low fecundity. In Europe dramatic population declines have taken place in common skate (Dipturus batis L.), one of the largest demersal fish in regional shelf seas, leading to extirpations from substantial parts of its former range. Here we report the discovery of cryptic species in common skate collected from the northeast Atlantic continental shelf. Data from nuclear microsatellite markers indicated two clearly distinct clades and phylogenetic analysis of mitochondrial DNA sequences demonstrated monophyly of each one of them. Capture locations showed evidence of strong spatial segregation, with one taxon occurring mainly in waters off the southern British Isles and around Rockall, while the other was restricted to more northerly shelf waters. These apparently cryptic species showed overlapping substrate and depth preferences, but distributional limits were closely related to temperature gradients, potentially indicating thermal limits to their distributions. This discovery of hidden diversity within a large, critically endangered marine vertebrate demonstrates how marine biodiversity can be underestimated, even in such a relatively well-studied and heavily exploited region. PMID:20106849

  20. Ice and ocean velocity in the Arctic marginal ice zone: Ice roughness and momentum transfer

    Directory of Open Access Journals (Sweden)

    Sylvia T. Cole

    2017-09-01

    Full Text Available The interplay between sea ice concentration, sea ice roughness, ocean stratification, and momentum transfer to the ice and ocean is subject to seasonal and decadal variations that are crucial to understanding the present and future air-ice-ocean system in the Arctic. In this study, continuous observations in the Canada Basin from March through December 2014 were used to investigate spatial differences and temporal changes in under-ice roughness and momentum transfer as the ice cover evolved seasonally. Observations of wind, ice, and ocean properties from four clusters of drifting instrument systems were complemented by direct drill-hole measurements and instrumented overhead flights by NASA operation IceBridge in March, as well as satellite remote sensing imagery about the instrument clusters. Spatially, directly estimated ice-ocean drag coefficients varied by a factor of three with rougher ice associated with smaller multi-year ice floe sizes embedded within the first-year-ice/multi-year-ice conglomerate. Temporal differences in the ice-ocean drag coefficient of 20–30% were observed prior to the mixed layer shoaling in summer and were associated with ice concentrations falling below 100%. The ice-ocean drag coefficient parameterization was found to be invalid in September with low ice concentrations and small ice floe sizes. Maximum momentum transfer to the ice occurred for moderate ice concentrations, and transfer to the ocean for the lowest ice concentrations and shallowest stratification. Wind work and ocean work on the ice were the dominant terms in the kinetic energy budget of the ice throughout the melt season, consistent with free drift conditions. Overall, ice topography, ice concentration, and the shallow summer mixed layer all influenced mixed layer currents and the transfer of momentum within the air-ice-ocean system. The observed changes in momentum transfer show that care must be taken to determine appropriate parameterizations

  1. Bacterial Ice Crystal Controlling Proteins

    Science.gov (United States)

    Lorv, Janet S. H.; Rose, David R.; Glick, Bernard R.

    2014-01-01

    Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions. PMID:24579057

  2. Sputtering of water ice

    DEFF Research Database (Denmark)

    Baragiola, R.A.; Vidal, R.A.; Svendsen, W.

    2003-01-01

    We present results of a range of experiments of sputtering of water ice together with a guide to the literature. We studied how sputtering depends on the projectile energy and fluence, ice growth temperature, irradiation temperature and external electric fields. We observed luminescence from...

  3. Ice sheet in peril

    DEFF Research Database (Denmark)

    Hvidberg, Christine Schøtt

    2016-01-01

    Earth's large ice sheets in Greenland and Antarctica are major contributors to sea level change. At present, the Greenland Ice Sheet (see the photo) is losing mass in response to climate warming in Greenland (1), but the present changes also include a long-term response to past climate transitions...

  4. Turning into Ice

    Science.gov (United States)

    Pietsch, Renée B.; Hanlon, Regina; Bohland, Cynthia; Schmale, David G., III

    2016-01-01

    This article describes an interdisciplinary unit in which students explore biological "ice nucleation"--by particles that cause water to freeze at temperatures above -38°C--through the lens of the microbial ice nucleator "Pseudomonas syringae." Such This activity, which aligns with the "Next Generation Science…

  5. GLERL Radiation Transfer Through Freshwater Ice

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Radiation transmittance (ratio of transmitted to incident radiation) through clear ice, refrozen slush ice and brash ice, from ice surface to ice-water interface in...

  6. Torque and Axial Loading Physics for Measuring Atmospheric Icing Load and Icing Rate

    OpenAIRE

    Mughal, Umair Najeeb; Virk, Muhammad Shakeel

    2015-01-01

    Measuring icing load and icing rate are important parameters for an atmospheric icing sensor. A new icing sensor has recently been designed and developed at Narvik University College for measuring atmospheric icing rate, icing load and icing type. Unlike the existing atmospheric icing sensors commercially available in market, which uses the axial loading for measuring icing load and icing rate, this new sensory system measures icing load and icing rate using the torque loading physics. The pe...

  7. Structure and mechanical implications of the pectoral fin skeleton in the Longnose Skate (Chondrichthyes, Batoidea).

    Science.gov (United States)

    Huang, Wei; Hongjamrassilp, Watcharapong; Jung, Jae-Young; Hastings, Philip A; Lubarda, Vlado A; McKittrick, Joanna

    2017-03-15

    Animal propulsion systems are believed to show high energy and mechanical efficiency in assisting movement compared to artificial designs. As an example, batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming via enlarged wing-like pectoral fins. The aim of this work is to illustrate the hierarchical structure of the pectoral fin of a representative batoid, the Longnose Skate (Raja rhina), and explain the mechanical implications of its structural design. At the macro level, the pectoral fins are comprised of radially oriented fin rays, formed by staggered mineralized skeletal elements stacked end-to-end. At the micro level, the midsection of each radial element is composed of three mineralized components, which consist of discrete segments (tesserae) that are mineralized cartilage and embedded in unmineralized cartilage. The radial elements are wrapped with aligned, unmineralized collagen fibers. This is the first report of the detailed structure of the ray elements, including the observation of a 3-chain mineralized tesserae. Structural analyses demonstrate that this configuration enhances stiffness in multiple directions. A two-dimensional numerical model based on the morphological analysis demonstrated that the tessera structure helps distributing shear, tensile and compressive stress more ideally, which can better support both lift and thrust forces when swimming without losing flexibility. Batoid fishes have very light cartilaginous skeletons that facilitate their elegant swimming by applying their enlarged wing-like pectoral fins. Previous studies have shown structural features and mechanical properties of the mineralized cartilage skeleton in various batoid fishes. However, the details of the pectoral fin structure at different length scales, as well as the relationship between the mechanical properties and structural design remains unknown. The present work illustrates the hierarchical structure of the pectoral fin of

  8. Embryonic development of the axial column in the little skate, Leucoraja erinacea.

    Science.gov (United States)

    Criswell, Katharine E; Coates, Michael I; Gillis, J Andrew

    2017-03-01

    The morphological patterns and molecular mechanisms of vertebral column development are well understood in bony fishes (osteichthyans). However, vertebral column morphology in elasmobranch chondrichthyans (e.g., sharks and skates) differs from that of osteichthyans, and its development has not been extensively studied. Here, we characterize vertebral development in an elasmobranch fish, the little skate, Leucoraja erinacea, using microCT, paraffin histology, and whole-mount skeletal preparations. Vertebral development begins with the condensation of mesenchyme, first around the notochord, and subsequently around the neural tube and caudal artery and vein. Mesenchyme surrounding the notochord differentiates into a continuous sheath of spindle-shaped cells, which forms the precursor to the mineralized areolar calcification of the centrum. Mesenchyme around the neural tube and caudal artery/vein becomes united by a population of mesenchymal cells that condenses lateral to the sheath of spindle-shaped cells, with this mesenchymal complex eventually differentiating into the hyaline cartilage of the future neural arches, hemal arches, and outer centrum. The initially continuous layers of areolar tissue and outer hyaline cartilage eventually subdivide into discrete centra and arches, with the notochord constricted in the center of each vertebra by a late-forming "inner layer" of hyaline cartilage, and by a ring of areolar calcification located medial to the outer vertebral cartilage. The vertebrae of elasmobranchs are distinct among vertebrates, both in terms of their composition (i.e., with centra consisting of up to three tissues layers-an inner cartilage layer, a calcified areolar ring, and an outer layer of hyaline cartilage), and their mode of development (i.e., the subdivision of arch and outer centrum cartilage from an initially continuous layer of hyaline cartilage). Given the evident variation in patterns of vertebral construction, broad taxon sampling, and

  9. O Skate e suas possibilidades educacionais The skateboarding and its educational possibility

    Directory of Open Access Journals (Sweden)

    Igor Armbrust

    2010-09-01

    Full Text Available Os esportes radicais têm sido objetos de discussões, devido ao interesse de aplicabilidade de seus conteúdos relacionados ao lazer, ao esporte e a educação. Todavia, ainda há certo despreparo profissional para empreender essas atividades, o que dificulta implantar tais práticas nos âmbitos educacionais. Este estudo, de natureza qualitativa, teve como objetivo apresentar uma proposta metodológica para organização de um curso de extensão universitária para graduandos e professores de educação física, com a finalidade de promover reflexões sobre os processos de iniciação à prática do skate atrelados ao esporte educacional. O estudo constou de pesquisa bibliográfica, apoiada em levantamentos de artigos, teses, dissertações, livros e sites, em que se relacionavam a prática do skate e sua ação educativa. Além disso, houve uma proposição de implementar uma proposta metodológica, no sentido de complementar os elementos da cultura corporal a ser vivenciada em âmbito escolar e efetivamente contribuir no processo de desenvolvimento do ser humano nos aspectos biológico, psicológico, social e cultural.The radical sports have been discussions' objects due to the interest of applicability of its contents related to leisure, sport, and education. Nevertheless, there is still some professional unprepared to undertake these activities, which makes difficult to introduce these practices in the educational ambit. This study, which has a qualitative character, had the aim to present a methodological proposal of organizing a college extension course for undergraduate students and teachers of physical education with the goal of promoting reflections about the processes of starting in the skateboarding practice coupled to educational sport. The study was consisted of a bibliographic research supported by a survey of articles, thesis, dissertations, books and, websites related to the skateboarding practice and its educative action

  10. Modelling snow ice and superimposed ice on landfast sea ice in Kongsfjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    Caixin Wang

    2015-08-01

    Full Text Available Snow ice and superimposed ice formation on landfast sea ice in a Svalbard fjord, Kongsfjorden, was investigated with a high-resolution thermodynamic snow and sea-ice model, applying meteorological weather station data as external forcing. The model shows that sea-ice formation occurs both at the ice bottom and at the snow/ice interface. Modelling results indicated that the total snow ice and superimposed ice, which formed at the snow/ice interface, was about 14 cm during the simulation period, accounting for about 15% of the total ice mass and 35% of the total ice growth. Introducing a time-dependent snow density improved the modelled results, and a time-dependent oceanic heat flux parameterization yielded reasonable ice growth at the ice bottom. Model results suggest that weather conditions, in particular air temperature and precipitation, as well as snow thermal properties and surface albedo are the most critical factors for the development of snow ice and superimposed ice in Kongsfjorden. While both warming air and higher precipitation led to increased snow ice and superimposed ice forming in Kongsfjorden in the model runs, the processes were more sensitive to precipitation than to air temperature.

  11. A esportivização do skate (1960-1990: relações entre o macro e o micro La deportivización del skate (1960-1990: relaciones entre lo macro y micro The sportivization of skateboarding (1960-1990: relations between the macro and the micro

    Directory of Open Access Journals (Sweden)

    Tony Honorato

    2013-03-01

    Full Text Available O objetivo deste estudo foi apresentar elementos da esportivização da prática cultural skate (1960-1990, como conhecimento para o entendimento da relação entre o micro e o macro processo sócio-histórico do skate. Como fonte de pesquisa histórica para a esportivização do skate no Brasil, dimensão macro, utilizamos a Revista Tribo Skate e para a de Piracicaba/SP, dimensão micro, entrevistamos dois colaboradores a partir do método da história oral. Os resultados evidenciaram que o skate surgiu para gerar fortes tensões agradáveis, suas formas de lazer precedem as formas esportivas e, guardadas as particularidades, os seus processos macro e micro-históricos são interdependentes.El objetivo del estudio fue presentar elementos de la deportivización de la práctica cultural skate (1960-1990, como conocimiento para el entendimiento de la relación entre el micro y macro proceso socio-histórico del mismo. Como fuente de investigación histórica para la deportivización del skate en Brasil, dimensión macro, utilizamos la Revista Tribo Skate y para la de Piracicaba/SP, dimensión micro, entrevistamos dos colaboradores a partir del método de historia oral. Los resultados evidenciaron que el skate surgió para generar fuertes tensiones agradables, sus formas de ocio preceden a sus formas deportivas y, salvando las particularidades, los procesos macro y micro-históricos son interdependientes.The objective of this study is to present the elements of the sportivization of the cultural practice of skateboarding (1960-1990, as knowledge for the understanding of the relation between the micro and the macro social and historical processes of skateboarding. We used the magazine Revista Tribo Skate as source of historical research for the sportivization of skateboarding in Brazil, the macro dimension, and for the micro dimension, the city of Piracicaba/SP, where we interviewed two collaborators based on the method of oral history. The results

  12. Surgical Repair of an Impalement Genital Injury from an Inline Skating Accident in a 7-Year-Old Prepubertal Girl: A Case Report.

    Science.gov (United States)

    Csorba, Roland; Engel, Joerg B; Wieg, Christian

    2017-02-01

    In girls who present with vaginal trauma, sexual abuse is often the primary diagnosis. The differential diagnosis must include patterns and the mechanism of injury that differentiate accidental injuries from inflicted trauma. A 7-year-old prepubertal girl presented to the emergency department with genital bleeding after a serious accidental impaling injury from inline skating. After rapid abduction of the legs and a fall onto the blade of an inline skate this child incurred an impaling genital injury consistent with an accidental mechanism. The dramatic genital injuries when repaired healed with almost imperceptible residual evidence of previous trauma. To our knowledge, this case report represents the first in the medical literature of an impaling vaginal trauma from an inline skate and describes its clinical and surgical management. Copyright © 2016 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

  13. Coulombic charge ice

    Science.gov (United States)

    McClarty, P. A.; O'Brien, A.; Pollmann, F.

    2014-05-01

    We consider a classical model of charges ±q on a pyrochlore lattice in the presence of long-range Coulomb interactions. This model first appeared in the early literature on charge order in magnetite [P. W. Anderson, Phys. Rev. 102, 1008 (1956), 10.1103/PhysRev.102.1008]. In the limit where the interactions become short ranged, the model has a ground state with an extensive entropy and dipolar charge-charge correlations. When long-range interactions are introduced, the exact degeneracy is broken. We study the thermodynamics of the model and show the presence of a correlated charge liquid within a temperature window in which the physics is well described as a liquid of screened charged defects. The structure factor in this phase, which has smeared pinch points at the reciprocal lattice points, may be used to detect charge ice experimentally. In addition, the model exhibits fractionally charged excitations ±q/2 which are shown to interact via a 1/r potential. At lower temperatures, the model exhibits a transition to a long-range ordered phase. We are able to treat the Coulombic charge ice model and the dipolar spin ice model on an equal footing by mapping both to a constrained charge model on the diamond lattice. We find that states of the two ice models are related by a staggering field which is reflected in the energetics of these two models. From this perspective, we can understand the origin of the spin ice and charge ice ground states as coming from a dipolar model on a diamond lattice. We study the properties of charge ice in an external electric field, finding that the correlated liquid is robust to the presence of a field in contrast to the case of spin ice in a magnetic field. Finally, we comment on the transport properties of Coulombic charge ice in the correlated liquid phase.

  14. Recipe and technology development for minced canned products of special purpose based on the underutilized north region fishery object (thorny skate

    Directory of Open Access Journals (Sweden)

    Raibulov S. P.

    2016-09-01

    Full Text Available The paper presents the results of justifying the use of thorny skate in the technology of minced meat canned products of special purpose. The key criterion determined the specialized purpose of canned food is the high content of physiologically functional food ingredient of chondroitin sulfate in the cartilage of thorny skate wings. The high content of chondroitin sulfate in raw materials ensures that the content of the physiologically functional ingredient in the finished canned food will be at the level from 220 to 250 mg per 100 g of product. The method of IR blanching is presented for removing urea from the thorny skate muscle tissue. To confirm the efficiency of the developed method of urea removal, it has been proposed to use a modified photocolorimetric method for determination of mass fractions of urea in feed flour according to the governmental standard GOST R 50032–92 "Feed flour made of fish, marine mammals, crustaceans and invertebrates. Methods of determining the mass fraction of urea and calculation of the crude protein with a given mass fraction of carbamide". With the help of this technique, the efficiency of urea removal from the thorny skate tissue by the proposed method has been determined. The residual urea content in the meat of thorny skate after IR blanching is 0.76 %, which is two times lesser than border value of sensitivity of the person (approximated as 1.2 %. The paper presents the materials of experimental substantiation of optimum formulation of new canned meat based on the method of fuzzy modeling. The ratio of the main components of the meatballs recipe (thorny skate and Atlantic cod close to the optimum is 48 % by weight of meat for each component separately.

  15. Creep of ice: further studies

    International Nuclear Information System (INIS)

    Heard, H.C.; Durham, W.B.; Kirby, S.H.

    1987-01-01

    Detailed studies have been done of ice creep as related to the icy satellites, Ganymede and Callisto. Included were: (1) the flow of high-pressure water ices II, III, and V, and (2) frictional sliding of ice I sub h. Work was also begun on the study of the effects of impurities on the flow of ice. Test results are summarized

  16. Nitric oxide production by nurse shark (Ginglymostoma cirratum) and clearnose skate (Raja eglanteria) peripheral blood leucocytes.

    Science.gov (United States)

    Walsh, Cathy J; Toranto, Jason D; Gilliland, C Taylor; Noyes, David R; Bodine, Ashby B; Luer, Carl A

    2006-01-01

    Reactive nitrogen intermediates, such as nitric oxide (NO), are important immunomodulators in vertebrate immune systems, but have yet to be identified as mediators of host defence in any member of class Chondrichthyes, the cartilaginous fishes. In the present study, production of NO by nurse shark (Ginglymostoma cirratum) peripheral blood leucocytes (PBL) stimulated with bacterial cell wall lipopolysaccharide (LPS) was investigated. PBL were cultured for 24 to 96 h following stimulation with LPS at concentrations ranging from 0 to 25 microg ml(-1), in both serum-supplemented and serum-free culture conditions. Production of NO was measured indirectly using the Griess reaction, with maximal NO production occurring after 72 h using 10% FBS and 10 microg LPS ml(-1). Application of these culture conditions to PBL from another cartilaginous fish (clearnose skate, Raja eglanteria) resulted in a similar NO response. Addition of a specific inhibitor of inducible nitric oxide synthase (iNOS), L-N(6)-(1-iminoethyl)lysine (L-NIL), resulted in a significant decrease in the production of NO by PBL from both species.

  17. A new skate genus Orbiraja (Rajiformes: Rajidae) from the Indo-West Pacific.

    Science.gov (United States)

    Last, Peter R; Weigmann, Simon; Dumale, Don

    2016-11-02

    Molecular analyses and information gleaned from an examination of the newly available adult male of the North-West Pacific skate, Okamejei jensenae Last & Lim, supported earlier concerns that the species might be mis-assigned. Morphological data based on this specimen supported its placement in a new genus Orbiraja that is assigned to the recently named Rostrorajini based on molecular evidence. This subgroup of the family Rajidae also includes Malacoraja, Neoraja, Rostroraja and an unresolved 'amphi-American Assemblage' (sensu McEachran & Dunn, 1998). Orbiraja is unique within the rajids in having the combination of three, very closely spaced median thorn rows on the tail, no dark-edged ventral pores, and a clasper skeleton with a prominent accessory terminal 3 cartilage formed by a medio-distal extension of the accessory terminal 2 cartilage. Its spiracle appears to be situated posteriorly with respect to the orbit. The group contains two other nominal species, Orbiraja powelli (Alcock) and O. philipi (Lloyd), and an un-named species from Indonesia that needs further investigation. Orbiraja jensenae is rediagnosed based on characteristics of the adult male.

  18. Reproductive biology of the spotback skate Atlantoraja castelnaui in the south-west Atlantic Ocean.

    Science.gov (United States)

    Colonello, J C; García, M L; Lasta, C A; Menni, R C

    2012-06-01

    This study provides information on the reproduction of spotback skate Atlantoraja castelnaui. A total of 232 individuals (119 females and 113 males) were obtained from surveys carried out between 2003 and 2006, from the south-west Atlantic Ocean, between 34 and 42° S and <50 m deep; another 514 specimens (241 females and 273 males) were obtained between 2005 and 2007 from commercial fishery operations carried out in the same area and landings in the port of Mar del Plata, Argentina. Males ranged from 185 to 1250 mm total length (L(T) ) and females from 243 to 1368 mm L(T) . Length at maturity was estimated to be 980 mm for males and 1089 mm L(T) for females. Lack of variation of testis mass together with the continuous production of mature spermatocyst and spermatozoa in deferent ducts suggested that males can reproduce throughout the year. Females reproduced year-round with peaks of reproductive activity an integral part of a continuous cycle. This conclusion is corroborated by the seasonal variation of ovaries, oviducal gland and the occurrence of females with eggs in the uterus throughout the year. Results from this study indicate that A. castelnaui is very susceptible to fishery pressure. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  19. Application of environmental DNA to detect an endangered marine skate species in the wild.

    Science.gov (United States)

    Weltz, Kay; Lyle, Jeremy M; Ovenden, Jennifer; Morgan, Jessica A T; Moreno, David A; Semmens, Jayson M

    2017-01-01

    Environmental DNA (eDNA) techniques have only recently been applied in the marine environment to detect the presence of marine species. Species-specific primers and probes were designed to detect the eDNA of the endangered Maugean skate (Zearaja maugeana) from as little as 1 L of water collected at depth (10-15 m) in Macquarie Harbour (MH), Tasmania. The identity of the eDNA was confirmed as Z. maugeana by sequencing the qPCR products and aligning these with the target sequence for a 100% match. This result has validated the use of this eDNA technique for detecting a rare species, Z. maugeana, in the wild. Being able to investigate the presence, and possibly the abundance, of Z. maugeana in MH and Bathurst harbour (BH), would be addressing a conservation imperative for the endangered Z. maugeana. For future application of this technique in the field, the rate of decay was determined for Z. maugeana eDNA under ambient dissolved oxygen (DO) levels (55% saturation) and lower DO (20% saturation) levels, revealing that the eDNA can be detected for 4 and 16 hours respectively, after which eDNA concentration drops below the detection threshold of the assay. With the rate of decay being influenced by starting eDNA concentrations, it is recommended that samples be filtered as soon as possible after collection to minimize further loss of eDNA prior to and during sample processing.

  20. Application of environmental DNA to detect an endangered marine skate species in the wild.

    Directory of Open Access Journals (Sweden)

    Kay Weltz

    Full Text Available Environmental DNA (eDNA techniques have only recently been applied in the marine environment to detect the presence of marine species. Species-specific primers and probes were designed to detect the eDNA of the endangered Maugean skate (Zearaja maugeana from as little as 1 L of water collected at depth (10-15 m in Macquarie Harbour (MH, Tasmania. The identity of the eDNA was confirmed as Z. maugeana by sequencing the qPCR products and aligning these with the target sequence for a 100% match. This result has validated the use of this eDNA technique for detecting a rare species, Z. maugeana, in the wild. Being able to investigate the presence, and possibly the abundance, of Z. maugeana in MH and Bathurst harbour (BH, would be addressing a conservation imperative for the endangered Z. maugeana. For future application of this technique in the field, the rate of decay was determined for Z. maugeana eDNA under ambient dissolved oxygen (DO levels (55% saturation and lower DO (20% saturation levels, revealing that the eDNA can be detected for 4 and 16 hours respectively, after which eDNA concentration drops below the detection threshold of the assay. With the rate of decay being influenced by starting eDNA concentrations, it is recommended that samples be filtered as soon as possible after collection to minimize further loss of eDNA prior to and during sample processing.

  1. The complete mitochondrial genome of the Korean skate: Hongeo koreana (Rajiformes, Rajidae).

    Science.gov (United States)

    Jeong, Dageum; Kim, Sung; Kim, Choong-Gon; Lee, Youn-Ho

    2014-12-01

    The complete mitochondrial genome of the Korean skate, Hongeo koreana, the sole member of its genus, is investigated for the first time. The genome consists of 16,906 bp in length including 2 rRNA, 22 tRNA and 13 protein coding genes with the same gene order and structure of the genome as those of other Rajidae species. The overall nucleotide composition of the L-strand is A = 29.8%, C = 27.9%, T = 27.9% and G = 14.3%, showing a high A + T bias. The anti-G bias (6.0%) is more significant in the third codon position. Twelve of the 13 protein-coding genes use ATG as their start codon while the COX1 gene starts with GTG. For stop codon, ND3 and ND4 genes show incomplete stop codon T. The mitogenome sequence of H. koreana will provide important information on the evolution and the phylogenetic relation of the genus Hongeo in relation to the other genera of the family Rajidae.

  2. Description and quantitative analysis of the dentition of the southern thorny skate Amblyraja doellojuradoi.

    Science.gov (United States)

    Delpiani, G; Spath, M C; Deli Antoni, M; Delpiani, M

    2017-06-01

    A description of the tooth morphology of 234 jaws from the southern thorny skate Amblyraja doellojuradoi in the south-west Atlantic Ocean is given. Seven rows of teeth were selected and length and width of each tooth in these rows were measured. It was found that functional series corresponds to the third teeth and the average width and length of these teeth were compared among jaws, maturity stages, sexes and rows. Generalized linear models were used to determine the subset of measures that most contribute to explain the variability between groups. It was observed that males have longer teeth than females, but the teeth of females are wider. These differences are attributed to reproductive behaviour, in which males bite females to hold them during copulation. This study provides a description of the teeth of A. doellojuradoi, supplying a valuable tool for identification of species. In addition, the establishment of the main variations observed in the dentition, improves the understanding of the species' biology. © 2017 The Fisheries Society of the British Isles.

  3. Complete mitochondrial genome of the mottled skate: Raja pulchra (Rajiformes, Rajidae).

    Science.gov (United States)

    Jeong, Dageum; Kim, Sung; Kim, Choong-Gon; Myoung, Jung-Goo; Lee, Youn-Ho

    2016-05-01

    The complete sequence of mitochondrial DNA of a mottled skate, Raja pulchra was sequenced as being circular molecules of 16,907 bp including 2 rRNA, 22 tRNA, 13 protein-coding genes (PCGs), and an AT-rich control region. The organization of the PCGs is the same as those found in other Rajidae species. The nucleotide of L-strand is composed of 29.8% A, 28.0% C, 27.9% T, and 14.3% G with a bias toward A + T slightly. Twelve of 13 PCGs are initiated by the ATG codon while COX1 starts with GTG. Only ND4 harbors the incomplete termination codon, TA. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA with the exception of [Formula: see text] which has a reduced DHU arm. This mitogenome will provide essential information for better phylogenetic resolution and precision of the family Rajidae and the genus Raja as well as for establishment of a fish stock recovery plan of the species.

  4. Complete mitochondrial genome of the Yellow-spotted skate Okamejei hollandi (Rajiformes: Rajidae).

    Science.gov (United States)

    Li, Weidong; Chen, Xiao; Liu, Wenai; Sun, Renjie; Zhou, Haolang

    2016-07-01

    The complete mitochondrial genome of the Yellow-spotted skate Okamejei hollandi was determined in this study. It is 16,974 bp in length and contains 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and one putative control region. The overall base composition is 30.5% A, 27.8% C, 14.0% G, and 27.8% T. There are 28 bp short intergenic spaces located in 12 gene junctions and 31 bp overlaps located in nine gene junctions in the whole mitogenome. Two start codons (ATG and GTG) and two stop codons (TAG and TAA/T) were used in the protein-coding genes. The lengths of 22 tRNA genes range from 68 (tRNA-Ser2) to 75 (tRNA-Leu1) bp. The origin of L-strand replication (OL) sequence (37 bp) was identified between the tRNA-Asn and tRNA-Cys genes. The control region is 1311 bp in length with high A + T and poor G content.

  5. The complete mitochondrial genome of the Longnose skate: Raja rhina (Rajiformes, Rajidae).

    Science.gov (United States)

    Jeong, Dageum; Lee, Youn-Ho

    2015-02-01

    The complete sequence of mitochondrial DNA of a longnose skate, Raja rhina was determined for the first time. It is 16,910 bp in length containing 2 rRNA, 22 tRNA and 13 protein coding genes with the same gene order and structure as those of other Rajidae species. The nucleotide of L-strand is composed of 30.1% A, 27.2% C, 28.5% T and 14.2% G, showing a slight A + T bias. The G is the least used base and markedly lower at the third codon position (5.4%). Twelve of the 13 protein coding genes use ATG as their start codon while the COX1 starts with GTG. As for stop codon, only ND4 shows incomplete stop codon TA. This mitogenome is the first report for a species of the genus Raja, and providing a valuable resource of genetic information for understanding the phylogenetic relationship and the evolution of the genus Raja as well as the family, Rajidae.

  6. Complete mitochondrial genome of the Yellownose skate: Zearaja chilensis (Rajiformes, Rajidae).

    Science.gov (United States)

    Jeong, Dageum; Lee, Youn-Ho

    2016-01-01

    The complete sequence of mitochondrial DNA of a Yellownose skate, Zearaja chilensis was determined for the first time. It is 16,909 bp in length covering 2 rRNA, 22 tRNA and 13 protein coding genes with the identical gene order and structure as those of other Rajidae species. The nucleotide of L-strand is composed of low G (14.3%), and slightly high A + T (58.9%) nucleotides. The strong codon usage bias against the use of G (6.0%) is found at the third codon positions. Twelve of the 13 protein coding genes use ATG as the start codon while COX1 starts with GTG. As for the stop codon, only ND4 shows an incomplete stop codon TA. This is the first report of the mitogenome for a species in the genus Zearaja, providing a valuable source of genetic information on the evolution of the family Rajidae and the genus Zearaja as well as for establishment of a sustainble fishery management plan of the species.

  7. Complete mitochondrial genome of the Kwangtung skate: Dipturus kwangtungensis (Rajiformes, Rajidae).

    Science.gov (United States)

    Jeong, Dageum; Kim, Sung; Kim, Choong-Gon; Lee, Youn-Ho

    2015-01-01

    The complete sequence of mitochondrial DNA of a Kwangtung skate, Dipturus kwangtungensis, was determined as being circular molecules of 16,912 bp including 2 rRNA, 22 tRNA, 13 protein coding genes (PCGs) and a control region. The arrangement of the PCGs is the same as that found in other Rajidae species. The nucleotide of L-strand which encodes most of the proteins is composed of 30.2% A, 27.4% C, 28.2% T and 14.2% G with a bias toward A+T slightly. Twelve of 13 PCGs are initiated by the ATG codon while COX1 starts with GTG. Only ND4 harbors the incomplete termination codon, TA. All tRNA genes have a typical clover-leaf structure of mitochondrial tRNA with the exception of tRNA(Ser)AGY, which has a reduced DHU arm. This mitogenome is the first report for a species of the genus Dipturus, which will become an important source of information on the phylogenetic relationship and the evolution of the genus Dipturus within the family Rajidae.

  8. THE CORRELATION BETWEEN THE PHYSICAL TRAINING AND THE SPORT PERFORMANCES IN SPEED SKATING AT CHILDREN

    Directory of Open Access Journals (Sweden)

    VAIDA Marius

    2010-04-01

    Full Text Available Sport practice at an early age is a problem of high actuality, this being debated intensely by specialists,the solving of the problem in cause being appreciated as a highly important factor in the general conception ofthe complex process of sport practice, in this process a very important role being held by the physical training.The present paper approaches the complex problem of the connection between the physical training andthe sport performances at children through an experiment realized on 6 speed skaters, 4 boys and 2 girls, withages of 8-9, experiment that had as purpose the demonstration of the importance of the multilateral physical training at skaters of an early age, of course without excluding the importance of the other factors necessary for superior results.Through the obtained results we proved that there is a direct connection between the physical training and the sport performances at children, knowing that the superior results in speed skating, on a long period, depend also by the training quality at an early age

  9. Vortex ice in nanostructured superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Reichhardt, Charles [Los Alamos National Laboratory; Reichhardt, Cynthia J [Los Alamos National Laboratory; Libal, Andras J [Los Alamos National Laboratory

    2008-01-01

    We demonstrate using numerical simulations of nanostructured superconductors that it is possible to realize vortex ice states that are analogous to square and kagome ice. The system can be brought into a state that obeys either global or local ice rules by applying an external current according to an annealing protocol. We explore the breakdown of the ice rules due to disorder in the nanostructure array and show that in square ice, topological defects appear along grain boundaries, while in kagome ice, individual defects appear. We argue that the vortex system offers significant advantages over other artificial ice systems.

  10. Ice Engineering Research Area

    Data.gov (United States)

    Federal Laboratory Consortium — Refrigerated Physical Modeling of Waterways in a Controlled EnvironmentThe Research Area in the Ice Engineering Facility at the Cold Regions Research and Engineering...

  11. Ice Cream Stick Math.

    Science.gov (United States)

    Paddock, Cynthia

    1992-01-01

    Described is a teaching technique which uses the collection of ice cream sticks as a means of increasing awareness of quantity in a self-contained elementary special class for students with learning disabilities and mild mental retardation. (DB)

  12. Global ice sheet modeling

    International Nuclear Information System (INIS)

    Hughes, T.J.; Fastook, J.L.

    1994-05-01

    The University of Maine conducted this study for Pacific Northwest Laboratory (PNL) as part of a global climate modeling task for site characterization of the potential nuclear waste respository site at Yucca Mountain, NV. The purpose of the study was to develop a global ice sheet dynamics model that will forecast the three-dimensional configuration of global ice sheets for specific climate change scenarios. The objective of the third (final) year of the work was to produce ice sheet data for glaciation scenarios covering the next 100,000 years. This was accomplished using both the map-plane and flowband solutions of our time-dependent, finite-element gridpoint model. The theory and equations used to develop the ice sheet models are presented. Three future scenarios were simulated by the model and results are discussed

  13. The Antartic Ice Borehole Probe

    Science.gov (United States)

    Behar, A.; Carsey, F.; Lane, A.; Engelhardt, H.

    2000-01-01

    The Antartic Ice Borehole Probe mission is a glaciological investigation, scheduled for November 2000-2001, that will place a probe in a hot-water drilled hole in the West Antartic ice sheet. The objectives of the probe are to observe ice-bed interactions with a downward looking camera, and ice inclusions and structure, including hypothesized ice accretion, with a side-looking camera.

  14. Intraindividuální komparace vybraných koordinačních ukazatelů bruslařského kroku na ledě a při in-line

    OpenAIRE

    Hospůdka, Jakub

    2010-01-01

    4 Summary: Title: Intraindividual comparison of selected indicators of coordinating steps on the ice skating and in-line. Objective: Assessment of coordination relationship rate of the skating forward during ice hockey and inline skating. Methods: Surface electromyography combinated with kinematography analysis used synchronized video recording. Results: Kinesiological content of movement during ice skating and inline skating is not the same. The general stereotype of the skating step is sign...

  15. Sexual dimorphism in sister species of Leucoraja skate and its relationship to reproductive strategy and life history.

    Science.gov (United States)

    Martinez, Christopher M; Rohlf, F James; Frisk, Michael G

    2016-01-01

    Instances of sexual dimorphism occur in a great variety of forms and manifestations. Most skates (Batoidea: Rajoidei) display some level of body shape dimorphism in which the pectoral fins of mature males develop to create a distinct bell-shaped body not found in females. This particular form of dimorphism is present in each of the sister species Leucoraja erinacea and Leucoraja ocellata, but differences between sexes are much greater in the former. In order to understand the nature and potential causes of pectoral dimorphism, we used geometric morphometrics to investigate allometry of fin shape in L. erinacea and L. ocellata and its relationship to the development of reproductive organs, based on previous work on the bonnethead shark, Sphyrna tiburo. We found that allometric trajectories of overall pectoral shape were different in both species of skate, but only L. erinacea varied significantly with respect to endoskeleton development. Male maturation was characterized by a number of sex-specific morphological changes, which appeared concurrently in developmental timing with elongation of cartilage-supported claspers. We suggest that external sexual dimorphism of pectoral fins in skates is a byproduct of skeletal growth needed for clasper development. Further, the magnitude of male shape change appears to be linked to the differential life histories of species. This work reports for the first time that pectoral dimorphism is a persistent feature in rajoid fishes, occurring in varying degrees across several genera. Lastly, our results suggest that pectoral morphology may be useful as a relative indicator of reproductive strategy in some species. © 2016 Wiley Periodicals, Inc.

  16. Ice recrystallization inhibition in ice cream by propylene glycol monostearate.

    Science.gov (United States)

    Aleong, J M; Frochot, S; Goff, H D

    2008-11-01

    The effectiveness of propylene glycol monostearate (PGMS) to inhibit ice recrystallization was evaluated in ice cream and frozen sucrose solutions. PGMS (0.3%) dramatically reduced ice crystal sizes in ice cream and in sucrose solutions frozen in a scraped-surface freezer before and after heat shock, but had no effect in quiescently frozen solutions. PGMS showed limited emulsifier properties by promoting smaller fat globule size distributions and enhanced partial coalescence in the mix and ice cream, respectively, but at a much lower level compared to conventional ice cream emulsifier. Low temperature scanning electron microscopy revealed highly irregular crystal morphology in both ice cream and sucrose solutions frozen in a scraped-surface freezer. There was strong evidence to suggest that PGMS directly interacts with ice crystals and interferes with normal surface propagation. Shear during freezing may be required for its distribution around the ice and sufficient surface coverage.

  17. Method for maintenance of ice beds of ice condenser containment

    International Nuclear Information System (INIS)

    Scrabis, C.M.; Hardin, R.T. Jr.

    1987-01-01

    This patent describes a method of maintaining ice baskets associated with a nuclear reactor system and disposed in an array of plural such ice baskets, supported in generally vertically oriented and parallel relationship by a lattice support structure which extends between the individual ice baskets and includes lateral supports adjacent the tops of the comprising: selecting an ice basket of the array requiring replenishment of the ice therewithin due to sublimation voids within the ice charges in the basket; isolating the selected ice basket; drilling a hole downwardly through the ice charges in the ice basket in general parallel axial relationship with respect to the cylindrical sidewall of the ice basket, utilizing a rotary drill bit connected through an auger to a rotary drive means; maintaining the rotary drive means in a fixed axial position and reversing the direction of rotation thereof for driving the auger in reverse rotation; and supplying ice in particulate form to the vicinity of the auger and conveying the particulate ice through the drilled hole by continued, reverse rotation of the auger so as to fill the sublimated voids in communication with the drilled hole, from the lowest and through successively higher such voids in the ice charges within the ice basket, and withdrawing the auger from the drilled hole as the voids are filled

  18. Morphological characters of the thickbody skate Amblyraja frerichsi (Krefft 1968 (Rajiformes: Rajidae, with notes on its biology.

    Directory of Open Access Journals (Sweden)

    Carlos Bustamante

    Full Text Available Detailed descriptions of morphological features, morphometrics, neurocranium anatomy, clasper structure and egg case descriptions are provided for the thickbody skate Amblyraja frerichsi; a rare, deep-water species from Chile, Argentina and Falkland Islands. The species diagnosis is complemented from new observations and aspects such as colour, size and distribution are described. Geographic and bathymetric distributional ranges are discussed as relevant features of this taxońs biology. Additionally, the conservation status is assessed including bycatch records from Chilean fisheries.

  19. Long-PCR based next generation sequencing of the whole mitochondrial genome of the peacock skate Pavoraja nitida (Elasmobranchii: Arhynchobatidae).

    Science.gov (United States)

    Yang, Lei; Naylor, Gavin J P

    2016-01-01

    We determined the complete mitochondrial genome sequence (16,760 bp) of the peacock skate Pavoraja nitida using a long-PCR based next generation sequencing method. It has 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and 1 control region in the typical vertebrate arrangement. Primers, protocols, and procedures used to obtain this mitogenome are provided. We anticipate that this approach will facilitate rapid collection of mitogenome sequences for studies on phylogenetic relationships, population genetics, and conservation of cartilaginous fishes.

  20. Icing losses on wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, T.; Fotsing, I.; Pearson, S. [Garrad Hassan Canada Inc., Ottawa, ON (Canada)

    2010-07-01

    This PowerPoint presentation discussed some of the energy losses that can occur as a result of icing on wind turbines. Airfoil deterioration can occur in the presence of rime and glaze ice. Anemometers are also impacted by ice, and shut-downs can occur as a result of icing events. Availability deficits that occur during the winter months can lead to annual energy losses of 0.5 percent. The impact of icing events on total wind power energy production in Quebec is estimated at between 1.3 percent to 2.7 percent. Ice loss estimates are considered during the pre-construction phases of wind power projects. However, ice loss prediction methods are often inaccurate. Studies have demonstrated that preconstruction masts show a reasonable correlation with wind turbine icing, and that icing losses are site-specific. tabs., figs.

  1. Age group athletes in inline skating: decrease in overall and increase in master athlete participation in the longest inline skating race in Europe – the Inline One-Eleven

    Science.gov (United States)

    Teutsch, Uwe; Knechtle, Beat; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

    2013-01-01

    Background Participation and performance trends in age group athletes have been investigated in endurance and ultraendurance races in swimming, cycling, running, and triathlon, but not in long-distance inline skating. The aim of this study was to investigate trends in participation, age, and performance in the longest inline race in Europe, the Inline One-Eleven over 111 km, held between 1998 and 2009. Methods The total number, age distribution, age at the time of the competition, and race times of male and female finishers at the Inline One-Eleven were analyzed. Results Overall participation increased until 2003 but decreased thereafter. During the 12-year period, the relative participation in skaters younger than 40 years old decreased while relative participation increased for skaters older than 40 years. The mean top ten skating time was 199 ± 9 minutes (range: 189–220 minutes) for men and 234 ± 17 minutes (range: 211–271 minutes) for women, respectively. The gender difference in performance remained stable at 17% ± 5% across years. Conclusion To summarize, although the participation of master long-distance inline skaters increased, the overall participation decreased across years in the Inline One-Eleven. The race times of the best female and male skaters stabilized across years with a gender difference in performance of 17% ± 5%. Further studies should focus on the participation in the international World Inline Cup races. PMID:23690697

  2. Ice flow Modelling of the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Nielsen, Lisbeth Tangaa

    Models of ice flow have a range of application in glaciology, including investigating the large-scale response of ice sheets to changes in climate, assimilating data to estimate unknown conditions beneath the ice sheet, and in interpreting proxy records obtained from ice cores, among others. In t...... a steady state with respect to the reference climate at the end of the simulation and that the mass balance of the ice sheet at this time was more sensitive to recent climate fluctuations than the temperature forcing in the early or mid-Holocene.......Models of ice flow have a range of application in glaciology, including investigating the large-scale response of ice sheets to changes in climate, assimilating data to estimate unknown conditions beneath the ice sheet, and in interpreting proxy records obtained from ice cores, among others....... In this PhD project, the use of ice flow models for the interpretation of the age-structure of the Greenland ice sheet, i.e. the depth within the ice, at which ice deposited at given times are found at present day. Two different observational data sets of this archive were investigated. Further, paleo...

  3. Modeling Commercial Turbofan Engine Icing Risk With Ice Crystal Ingestion

    Science.gov (United States)

    Jorgenson, Philip C. E.; Veres, Joseph P.

    2013-01-01

    The occurrence of ice accretion within commercial high bypass aircraft turbine engines has been reported under certain atmospheric conditions. Engine anomalies have taken place at high altitudes that have been attributed to ice crystal ingestion, partially melting, and ice accretion on the compression system components. The result was degraded engine performance, and one or more of the following: loss of thrust control (roll back), compressor surge or stall, and flameout of the combustor. As ice crystals are ingested into the fan and low pressure compression system, the increase in air temperature causes a portion of the ice crystals to melt. It is hypothesized that this allows the ice-water mixture to cover the metal surfaces of the compressor stationary components which leads to ice accretion through evaporative cooling. Ice accretion causes a blockage which subsequently results in the deterioration in performance of the compressor and engine. The focus of this research is to apply an engine icing computational tool to simulate the flow through a turbofan engine and assess the risk of ice accretion. The tool is comprised of an engine system thermodynamic cycle code, a compressor flow analysis code, and an ice particle melt code that has the capability of determining the rate of sublimation, melting, and evaporation through the compressor flow path, without modeling the actual ice accretion. A commercial turbofan engine which has previously experienced icing events during operation in a high altitude ice crystal environment has been tested in the Propulsion Systems Laboratory (PSL) altitude test facility at NASA Glenn Research Center. The PSL has the capability to produce a continuous ice cloud which are ingested by the engine during operation over a range of altitude conditions. The PSL test results confirmed that there was ice accretion in the engine due to ice crystal ingestion, at the same simulated altitude operating conditions as experienced previously in

  4. Life-history traits of the long-nosed skate Dipturus oxyrinchus.

    Science.gov (United States)

    Bellodi, A; Porcu, C; Cannas, R; Cau, Al; Marongiu, M F; Mulas, A; Vittori, S; Follesa, M C

    2017-03-01

    This work investigates life-history traits of the long-nosed skate Dipturus oxyrinchus, which is a common by-catch in Sardinian waters. The reproductive variables were analysed from 979 specimens sampled during scientific and commercial hauls. Females (10·4-117·5 cm total length, L T ) attained larger sizes than males (14·5-99·5 cm L T ). To evaluate age and growth, a sub-sample of 130 individuals (76 females and 54 males) were used. The age was estimated by annuli counts of sectioned vertebral centra. Four models were used for the length-at-age data: the von Bertalanffy, the exponential, the Gompertz and the logistic functions. According to the Akaike's information criterion, the Gompertz model seemed to provide the best fitting curve (L ∞ mean ± s.e.: 127·55 ± 4·90 cm, k: 0·14 ± 0·09, IP: 3·97 ± 0·90 years). The oldest female and male were aged 17 (115·5 cm L T ) and 15 years (96·0 cm L T ), respectively. Lengths at maturity were 103·5 cm for females and 91·0 cm for males, corresponding to 90% of the maximum observed length in both sexes. The monthly distribution of maturity stages highlighted an extended reproductive cycle, with spawning females and active males being present almost throughout the year, as confirmed by the gonado-somatic index. Ovarian fecundity reached a maximum of 26 yolked follicles with a mean ± s.e. size of 19·7 ± 6·5 mm. © 2016 The Fisheries Society of the British Isles.

  5. New African species of Echinobothrium (Cestoda: Diphyllidea) and implications for the identities of their skate hosts.

    Science.gov (United States)

    Caira, J N; Rodriguez, N; Pickering, M

    2013-10-01

    Two new species of diphyllidean cestodes of the genus Echinobothrium, each hosted by a different skate species in the Raja miraletus complex, are described. Echinobothrium mercedesae n. sp. is described from R. cf. miraletus 2 off Senegal. Echinobothrium yiae n. sp. is described from R. cf. miraletus 1 off South Africa. Both species are small worms that differ from their 29 described congeners in the combination of number of cephalic peduncle spines per column, hook formula, number and arrangement of testes, and arrangement of vitelline follicles. They are easily distinguished from one another in that whereas the vitelline follicles of E. yiae n. sp. are circumcortical, they are lateral in E. mercedesae n. sp., and also in number of cephalic peduncle spines per column (14-17 vs. 10-12). Echinobothrium yiae n. sp. is also unusual in that the cephalic peduncle spines stop short of the anterior margin of the peduncle. In addition, although the paucity of available material precluded their formal description, evidence of 2 additional new species parasitizing R. miraletus also from Senegal is presented. In combination these worms provide support for the interpretation that what is currently recognized as Raja miraletus actually consists of a complex of geographically restricted species, rather than a polymorphic species of multiple parapatric or allopatrically distributed populations. This interpretation is not only supported by previously published molecular data, but also by newly collected morphological data involving differences in the color patterns of disc ocelli among host specimens of the 3 forms available as a result of digital efforts to ensure the accuracy of host identifications, which are also presented here.

  6. Neurotransmitter modulation of extracellular H+ fluxes from isolated retinal horizontal cells of the skate

    Science.gov (United States)

    Molina, Anthony J A; Verzi, Michael P; Birnbaum, Andrea D; Yamoah, Ebenezer N; Hammar, Katherine; Smith, Peter J S; Malchow, Robert Paul

    2004-01-01

    Self-referencing H+-selective microelectrodes were used to measure extracellular H+ fluxes from horizontal cells isolated from the skate retina. A standing H+ flux was detected from quiescent cells, indicating a higher concentration of free hydrogen ions near the extracellular surface of the cell as compared to the surrounding solution. The standing H+ flux was reduced by removal of extracellular sodium or application of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), suggesting activity of a Na+–H+ exchanger. Glutamate decreased H+ flux, lowering the concentration of free hydrogen ions around the cell. AMPA/kainate receptor agonists mimicked the response, and the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) eliminated the effects of glutamate and kainate. Metabotropic glutamate agonists were without effect. Glutamate-induced alterations in H+ flux required extracellular calcium, and were abolished when cells were bathed in an alkaline Ringer solution. Increasing intracellular calcium by photolysis of the caged calcium compound NP-EGTA also altered extracellular H+ flux. Immunocytochemical localization of the plasmalemma Ca2+–H+-ATPase (PMCA pump) revealed intense labelling within the outer plexiform layer and on isolated horizontal cells. Our results suggest that glutamate modulation of H+ flux arises from calcium entry into cells with subsequent activation of the plasmalemma Ca2+–H+-ATPase. These neurotransmitter-induced changes in extracellular pH have the potential to play a modulatory role in synaptic processing in the outer retina. However, our findings argue against the hypothesis that hydrogen ions released by horizontal cells normally act as the inhibitory feedback neurotransmitter onto photoreceptor synaptic terminals to create the surround portion of the centre-surround receptive fields of retinal neurones. PMID:15272044

  7. Glutamate modulation of GABA transport in retinal horizontal cells of the skate

    Science.gov (United States)

    Kreitzer, Matthew A; Andersen, Kristen A; Malchow, Robert Paul

    2003-01-01

    Transport of the amino acid GABA into neurons and glia plays a key role in regulating the effects of GABA in the vertebrate retina. We have examined the modulation of GABA-elicited transport currents of retinal horizontal cells by glutamate, the likely neurotransmitter of vertebrate photoreceptors. Enzymatically isolated external horizontal cells of skate were examined using whole-cell voltage-clamp techniques. GABA (1 mm) elicited an inward current that was completely suppressed by the GABA transport inhibitors tiagabine (10 μm) and SKF89976-A (100 μm), but was unaffected by 100 μm picrotoxin. Prior application of 100 μm glutamate significantly reduced the GABA-elicited current. Glutamate depressed the GABA dose-response curve without shifting the curve laterally or altering the voltage dependence of the current. The ionotropic glutamate receptor agonists kainate and AMPA also reduced the GABA-elicited current, and the effects of glutamate and kainate were abolished by the ionotropic glutamate receptor antagonist 6-cyano-7-nitroquinoxaline. NMDA neither elicited a current nor modified the GABA-induced current, and metabotropic glutamate analogues were also without effect. Inhibition of the GABA-elicited current by glutamate and kainate was reduced when extracellular calcium was removed and when recording pipettes contained high concentrations of the calcium chelator BAPTA. Caffeine (5 mm) and thapsigargin (2 nm), agents known to alter intracellular calcium levels, also reduced the GABA-elicited current, but increases in calcium induced by depolarization alone did not. Our data suggest that glutamate regulates GABA transport in retinal horizontal cells through a calcium-dependent process, and imply a close physical relationship between calcium-permeable glutamate receptors and GABA transporters in these cells. PMID:12562999

  8. Objectifying Tactics: Athlete and Race Variability in Elite Short-Track Speed Skating.

    Science.gov (United States)

    Konings, Marco J; Hettinga, Florentina J

    2018-02-01

    To objectively capture and understand tactical considerations in a race, the authors explored whether race-to-race variation of an athlete and the variation of competitors within a race could provide insight into how and when athletes modify their pacing decisions in response to other competitors. Lap times of elite 500-, 1000-, and 1500-m short-track speed-skating competitions from 2011 to 2016 (N = 6965 races) were collected. Log-transformed lap and finishing times were analyzed with mixed linear models. To determine within-athlete race-to-race variability, athlete identity (between-athletes differences) and the residual (within-athlete race-to-race variation) were added as random effects. To determine race variability, race identity (between-races differences) and the residual (within-race variation) were added as random effects. Separate analyses were performed for each event. Within-athlete race-to-race variability of the finishing times increased with prolonged distance of the event (500-m, CV = 1.6%; 1000-m, CV = 2.8%; 1500-m, CV = 4.1%), mainly due to higher within-athlete race-to-race variability in the initial phase of 1000-m (3.3-6.9%) and 1500-m competitions (8.7-12.2%). During these early stages, within-race variability is relatively low in 1000-m (1.1-1.4%) and 1500-m (1.3-2.8%) competitions. The present study demonstrated how analyses of athlete and race variability could provide insight into tactical pacing decisions in sports where finishing position is emphasized over finishing time. The high variability of short-track skaters is a result of the decision to alter initial pacing behavior based on the behavior of other competitors in their race, emphasizing the importance of athlete-environment interactions in the context of pacing.

  9. Pacing Behavior and Tactical Positioning in 500- and 1000-m Short-Track Speed Skating.

    Science.gov (United States)

    Noorbergen, Olaf S; Konings, Marco J; Micklewright, Dominic; Elferink-Gemser, Marije T; Hettinga, Florentina J

    2016-09-01

    To explore pacing behavior and tactical positioning during the shorter 500- and 1000-m short-track competitions. Lap times and intermediate rankings of elite 500- and 1000-m short-track-skating competitors were collected over the 2012-13 season. First, lap times were analyzed using a MANOVA, and for each lap, differences between sex, race type, final ranking, and stage of competition were determined. Second, Kendall tau-b correlations were used to assess relationships between intermediate and final rankings. In addition, intermediate rankings of the winner of each race were examined. Top-placed athletes appeared faster than bottom-placed athletes in every lap in the 500-m, while in the 1000-m no differences were found until the final 4 laps (P < .05). Correlations between intermediate and final rankings were already high at the beginning stages of the 50-m (lap 1: r = .59) but not for the 1000-m (lap 1: r = .21). Although 500- and 1000-m short-track races are both relatively short, fundamental differences in pacing behavior and tactical positioning were found. A fast-start strategy seems to be optimal for 500-m races, while the crucial segment in 1000-m races seems to be from the 6th lap to the finish line (ie, after ± 650 m). These findings provide evidence to suggest that athletes balance between choosing an energetically optimal profile and the tactical and positional benefits that play a role when riding against an opponent, as well as contributing to developing novel insights in exploring athletic behavior when racing against opponents.

  10. Nuevo centro olímpico en Lake Placid, EE.UU

    Directory of Open Access Journals (Sweden)

    Hellmuth, George

    1980-09-01

    Full Text Available This new sports center, site of the 1980 Winter Olympic Games, consists of a main ice rink of Olympic size with seating for 8000 spectators, in addition to a smaller rink used for the U.S. Games. The auxiliary services are found under the stands or in the structure which joins the new center to the rink used for the 1932 Games. The complex is completed with a Higher School and an oval rink for speed skating. With the combination of visible beams in white, seats in bright red, dark blue ceilings, outside stairways enclosed in glass and outside walls with white insulating panels, a pleasant overall effect is achieved both on the outside as well as inside.

    Este nuevo centro deportivo, sede de los Juegos Olímpicos de Invierno de 1980, consta de una pista principal de hielo de dimensiones olímpicas con unos graderíos para 8.000 personas, y de una pista más pequeña utilizada para los Juegos U.S.A. Los servicios auxiliares se encuentran debajo de las gradas o en la estructura que enlaza el nuevo Centro con la pista ya empleada en los anteriores Juegos de 1932. Completa el complejo una Escuela Superior y una pista de forma oval para patinaje de velocidad. Con la combinación de vigas al descubierto en color blanco, asientos en color rojo brillante, techos en color azul oscuro, escaleras exteriores rodeadas de cristal y muros exteriores con paneles aislantes en color blanco se obtiene un agradable conjunto tanto en el aspecto exterior como en el interior.

  11. Gosto musical e hexis corporal: a questão do estilo na prática do skate de rua em Ponta Grossa-PR

    Directory of Open Access Journals (Sweden)

    Adriano Albuquerque Barreto

    2017-04-01

    Full Text Available http://dx.doi.org/10.5007/2175-8042.2017v29n50p50 Nosso trabalho é uma análise da estética musical incorporada por um grupo de skatistas e sua relação com do estilo de skate desenvolvido pelos praticantes. A hexis corporal na prática do skate de rua, em nosso espaço de investigação, se mostrou associada com o gosto musical do grupo em questão. Deste modo, nosso propósito foi evidenciar essas referências musicais e seu impacto na formação do estilo do skate praticado. Nossa experiência antropológica com os skatistas e o referencial teórico inspirado pela leitura dos trabalhos de Bourdieu sobre estética musical e a hexis corporal foram nossas fontes de pesquisa. Partindo de uma breve história da skatemusic e da exposição dos skatistas sobre a influência do estilo musical no estilo da prática do skate, exploramos o habitus destes enquanto interdependências dos grupos e parte de um charme ou carisma na conformação dos skaters.

  12. La cultura skate en las sociedades contemporáneas: una aproximación etnográfica a la ciudad de Madrid

    Directory of Open Access Journals (Sweden)

    Israel Márquez

    2015-01-01

    Full Text Available Este artículo propone un acercamiento al fenómeno del skate en la ciudad de Madrid a partir de un estudio etnográfico multisituado en el que se combina investigación online y offline. A partir de esta metodología, ofrecemos una interpretación de algunas de las principales características que presenta la cultura skate en nuestra sociedad, particularmente en la ciudad de Madrid, poniendo énfasis en los aspectos más intersubjetivos y culturales de esta realidad. La práctica del skate en Madrid ha experimentado un visible incremento en los últimos años y el marco analítico que proponemos para el estudio de su difusión y generalización responde a cambios en el orden cultural de las sociedad occidentales y de la propia cultura skate, en dinámica interdependencia con la esfera económica, como orden de producción y distribución de servicios y productos culturales y deportivos.

  13. The ICES system

    International Nuclear Information System (INIS)

    Inzaghi, A.

    1983-01-01

    ICES is an integrated system used in the various engineering fields. It is made up of the Basic System and the applied Subsystems. ICES is controlled by the Operating System of the computer, from which it calls for suitable services: space allocation, loading of the modules etc... To be able to use software of this type on a computer the Operating System should be made more general. The Subsystems are developed with special programs included in the ICES Basic System. Each Subsystem is associated with an area of application. In other words, a Subsystem can only treat a previously defined ''class of problems''. The engineer (user) communicates with the Subsystem using a language oriented towards the problem (POL) also previously defined using the CDL language. The use of the (POL) language makes the engineer-computer contact much easier. The applied programs written in ICETRAN, once supplied as input to the ICETRAN Precompiler, become Fortran programs with special characteristics. A Fortran compiler produces the corresponding object programs with which, using the ICES ''Link-edit'' procedures, one obtains the modules which can be executed by an ICES Subsystem

  14. Ice Engineering. Number 25, September 2000. Remote Ice Motion Detection

    National Research Council Canada - National Science Library

    2000-01-01

    .... Government agencies, and the engineering community in general. The potential exists for property damage, serious injury, and fatalities during ice-related flooding, evacuations, and other ice mitigation operations...

  15. Anticancer Activity of a Hexapeptide from Skate (Raja porosa Cartilage Protein Hydrolysate in HeLa Cells

    Directory of Open Access Journals (Sweden)

    Xin Pan

    2016-08-01

    Full Text Available In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY, which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC50 of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p < 0.01. Thus, FIMGPY could induce apoptosis by upregulating the Bax/Bcl-2 ratio and caspase-3 activation. Using a DNA ladder method further confirmed that the anti-proliferation activity of FIMGPY was attributable to its role in inducing apoptosis. These results suggest that FIMGPY from skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer.

  16. Anticancer Activity of a Hexapeptide from Skate (Raja porosa) Cartilage Protein Hydrolysate in HeLa Cells.

    Science.gov (United States)

    Pan, Xin; Zhao, Yu-Qin; Hu, Fa-Yuan; Chi, Chang-Feng; Wang, Bin

    2016-08-16

    In this study, the hexapeptide Phe-Ile-Met-Gly-Pro-Tyr (FIMGPY), which has a molecular weight of 726.9 Da, was separated from skate (Raja porosa) cartilage protein hydrolysate using ultrafiltration and chromatographic methods, and its anticancer activity was evaluated in HeLa cells. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay indicated that FIMGPY exhibited high, dose-dependent anti-proliferation activities in HeLa cells with an IC50 of 4.81 mg/mL. Acridine orange/ethidium bromide (AO/EB) fluorescence staining and flow cytometry methods confirmed that FIMGPY could inhibit HeLa cell proliferation by inducing apoptosis. Western blot assay revealed that the Bax/Bcl-2 ratio and relative intensity of caspase-3 in HeLa cells treated with 7-mg/mL FIMGPY were 2.63 and 1.83, respectively, significantly higher than those of the blank control (p skate cartilage protein hydrolysate may have applications as functional foods and nutraceuticals for the treatment and prevention of cancer.

  17. Spawning Characteristics and Artificial Hatching of Female Mottled Skate, Beringraja pulchra in the West Coast of Korea.

    Science.gov (United States)

    Kang, Hee-Woong; Jo, Yeong-Rok; Kang, Duk-Yong; Jeong, Gyeong-Suk; Jo, Hyun-Su

    2013-09-01

    The gonadsomatic index (GSI) of mottled skate was the highest in April, GSI and HSI showed a reverse phase for its reproductive cycle. The fish had one pair of egg capsules, having 1 to 7 fertilized eggs, and spawned all the year round. When surveying the reproductive characteristics of females over 63 ㎝ in disc width, we found the spawning peak was between April to June, and the appearance ratio of egg capsules was the highest in May (32.1%). The eggs were hatched at 8°C, 13°C, 18°C, water temperature (12.8 to 24.2°C), and the best hatching temperature was 18°C. The number of fish hatched was 4 to 5 fish/egg capsules, and the hatching rate was 100%. The sex ratios of hatching larvae were 45.5% female and 54.5% male. Therefore this study will provide fundamental data and information for artificial reproduction of the mottled skate.

  18. Angiotensin-I converting enzyme inhibitory peptides from antihypertensive skate (Okamejei kenojei) skin gelatin hydrolysate in spontaneously hypertensive rats.

    Science.gov (United States)

    Ngo, Dai-Hung; Kang, Kyong-Hwa; Ryu, BoMi; Vo, Thanh-Sang; Jung, Won-Kyo; Byun, Hee-Guk; Kim, Se-Kwon

    2015-05-01

    The aim of this study was to investigate antihypertensive effect of bioactive peptides from skate (Okamejei kenojei) skin gelatin. The Alcalase/protease gelatin hydrolysate below 1 kDa (SAP) exhibited the highest angiotensin-I converting enzyme (ACE) inhibition compared to other hydrolysates. SAP can decrease systolic blood pressure significantly in spontaneously hypertensive rats. SAP inhibited vasoconstriction via PPAR-γ expression, activation and phosphorylation of eNOS in lungs. Moreover, the expression levels of endothelin-1, RhoA, α-smooth muscle actin, cleaved caspase 3 and MAPK were decreased by SAP in lungs. Vascularity, muscularization and cellular proliferation in lungs were detected by immunohistochemical staining. Finally, two purified peptides (LGPLGHQ, 720Da and MVGSAPGVL, 829Da) showed potent ACE inhibition with IC50 values of 4.22 and 3.09 μM, respectively. These results indicate that bioactive peptides isolated from skate skin gelatin may serve as candidates against hypertension and could be used as functional food ingredients. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Modeling of competitive activity of skilled athletes specialized at 1500 m distance on short-track skating

    Directory of Open Access Journals (Sweden)

    O.S. Kholodova

    2013-10-01

    Full Text Available Background: Models of competitive activity at the 1500 m distance on short-track skating are developed on the basis of defining the relationship between sports results and major characteristics which describe speed of running at different parts of the distance. Material: we analyzed reports of competitions at the European and World Championships, World Cups 2007-2011. The dynamics of the speed finalists of the competition at the 1500 m - in hits (n = 33, quarterfinals (n = 34, semi-finals (n = 32 and finals (n = 39. Results: it was determined that for a distance of 1500 m short track skating is the most appropriate model with factors of influence: the speed of the first to sixth part of distance , the speed difference between the first and second half of the distance, time of the slowest circle, the difference between the time of the slowest and fastest circles. Conclusions: time of overcoming of distance will diminish at the rational change of model indexes. It will allow to increase possibility of output in the next circle of competitions and accordingly improve a place in final protocol.

  20. On the Ice Nucleation Spectrum

    Science.gov (United States)

    Barahona, D.

    2012-01-01

    This work presents a novel formulation of the ice nucleation spectrum, i.e. the function relating the ice crystal concentration to cloud formation conditions and aerosol properties. The new formulation is physically-based and explicitly accounts for the dependency of the ice crystal concentration on temperature, supersaturation, cooling rate, and particle size, surface area and composition. This is achieved by introducing the concepts of ice nucleation coefficient (the number of ice germs present in a particle) and nucleation probability dispersion function (the distribution of ice nucleation coefficients within the aerosol population). The new formulation is used to generate ice nucleation parameterizations for the homogeneous freezing of cloud droplets and the heterogeneous deposition ice nucleation on dust and soot ice nuclei. For homogeneous freezing, it was found that by increasing the dispersion in the droplet volume distribution the fraction of supercooled droplets in the population increases. For heterogeneous ice nucleation the new formulation consistently describes singular and stochastic behavior within a single framework. Using a fundamentally stochastic approach, both cooling rate independence and constancy of the ice nucleation fraction over time, features typically associated with singular behavior, were reproduced. Analysis of the temporal dependency of the ice nucleation spectrum suggested that experimental methods that measure the ice nucleation fraction over few seconds would tend to underestimate the ice nuclei concentration. It is shown that inferring the aerosol heterogeneous ice nucleation properties from measurements of the onset supersaturation and temperature may carry significant error as the variability in ice nucleation properties within the aerosol population is not accounted for. This work provides a simple and rigorous ice nucleation framework where theoretical predictions, laboratory measurements and field campaign data can be

  1. Rheology of planetary ices

    Energy Technology Data Exchange (ETDEWEB)

    Durham, W.B. [Lawrence Livermore National Lab., CA (United States); Kirby, S.H.; Stern, L.A. [Geological Survey, Menlo Park, CA (United States)

    1996-04-24

    The brittle and ductile rheology of ices of water, ammonia, methane, and other volatiles, in combination with rock particles and each other, have a primary influence of the evolution and ongoing tectonics of icy moons of the outer solar system. Laboratory experiments help constrain the rheology of solar system ices. Standard experimental techniques can be used because the physical conditions under which most solar system ices exist are within reach of conventional rock mechanics testing machines, adapted to the low subsolidus temperatures of the materials in question. The purpose of this review is to summarize the results of a decade-long experimental deformation program and to provide some background in deformation physics in order to lend some appreciation to the application of these measurements to the planetary setting.

  2. Ice accreditation vs wind

    Energy Technology Data Exchange (ETDEWEB)

    Sabourin, G. [Hydro-Quebec, PQ (Canada). TransEnergie Div.; Chouinard, L. [McGill Univ., Montreal, PQ (Canada); Feknous, N. [SNC-Lavalin, Montreal, PQ (Canada)

    2002-07-01

    Wind and ice data from Hydro Quebec and Environment Canada indicates that winds during ice storms are in the general direction of the St. Lawrence River. This observation is important for upgrading existing power transmission lines from the Manicouagan and Churchill generation system because they are parallel to the St. Lawrence and they were designed with lower criteria than is currently accepted. ASCE 74 suggests an accumulation ratio based on thickness of 0.70 for winds parallel to the line. The Goodwin model was used to calculate this ratio. The presentation includes illustrations showing the accumulation ratio for a north wind, as well as the accumulation ratios and wind roses at Quebec. A table showing a comparison of ratios from passive ice meters shows that results are similar to mean values from the theoretical model.

  3. Ice cores and palaeoclimate

    International Nuclear Information System (INIS)

    Krogh Andersen, K.; Ditlevsen, P.; Steffensen, J.P.

    2001-01-01

    Ice cores from Greenland give testimony of a highly variable climate during the last glacial period. Dramatic climate warmings of 15 to 25 deg. C for the annual average temperature in less than a human lifetime have been documented. Several questions arise: Why is the Holocene so stable? Is climatic instability only a property of glacial periods? What is the mechanism behind the sudden climate changes? Are the increased temperatures in the past century man-made? And what happens in the future? The ice core community tries to attack some of these problems. The NGRIP ice core currently being drilled is analysed in very high detail, allowing for a very precise dating of climate events. It will be possible to study some of the fast changes on a year by year basis and from this we expect to find clues to the sequence of events during rapid changes. New techniques are hoped to allow for detection of annual layers as far back as 100,000 years and thus a much improved time scale over past climate changes. It is also hoped to find ice from the Eemian period. If the Eemian layers confirm the GRIP sequence, the Eemian was actually climatically unstable just as the glacial period. This would mean that the stability of the Holocene is unique. It would also mean, that if human made global warming indeed occurs, we could jeopardize the Holocene stability and create an unstable 'Eemian situation' which ultimately could start an ice age. Currenlty mankind is changing the composition of the atmosphere. Ice cores document significant increases in greenhouse gases, and due to increased emissions of sulfuric and nitric acid from fossil fuel burning, combustion engines and agriculture, modern Greenland snow is 3 - 5 times more acidic than pre-industrial snow (Mayewski et al., 1986). However, the magnitude and abruptness of the temperature changes of the past century do not exceed the magnitude of natural variability. It is from the ice core perspective thus not possible to attribute the

  4. ICE Online Detainee Locator System

    Data.gov (United States)

    Department of Homeland Security — The Online Detainee Locator datasets provide the location of a detainee who is currently in ICE custody, or who was release from ICE custody for any reason with the...

  5. Ice recrystallization inhibition in ice cream as affected by ice structuring proteins from winter wheat grass.

    Science.gov (United States)

    Regand, A; Goff, H D

    2006-01-01

    Ice recrystallization in quiescently frozen sucrose solutions that contained some of the ingredients commonly found in ice cream and in ice cream manufactured under commercial conditions, with or without ice structuring proteins (ISP) from cold-acclimated winter wheat grass extract (AWWE), was assessed by bright field microscopy. In sucrose solutions, critical differences in moisture content, viscosity, ionic strength, and other properties derived from the presence of other ingredients (skim milk powder, corn syrup solids, locust bean gum) caused a reduction in ice crystal growth. Significant ISP activity in retarding ice crystal growth was observed in all solutions (44% for the most complex mix) containing 0.13% total protein from AWWE. In heat-shocked ice cream, ice recrystallization rates were significantly reduced 40 and 46% with the addition of 0.0025 and 0.0037% total protein from AWWE. The ISP activity in ice cream was not hindered by its inclusion in mix prior to pasteurization. A synergistic effect between ISP and stabilizer was observed, as ISP activity was reduced in the absence of stabilizer in ice cream formulations. A remarkably smoother texture for ice creams containing ISP after heat-shock storage was evident by sensory evaluation. The efficiency of ISP from AWWE in controlling ice crystal growth in ice cream has been demonstrated.

  6. Veřejné bruslařské školy

    OpenAIRE

    Vejpravová, Dominika

    2014-01-01

    Title of the thesis: Public skating schools Aim: Mapping of teaching in public skating schools in the selected region. Comparison of methods of teaching skating at these schools on the base of observations and interviews with the coaches. The proposal optimal model of teaching skating suitable for use in public skating schools. The work covers the fundamentals of skating. Key words: Ice - skating, child, school.

  7. The IceProd Framework

    DEFF Research Database (Denmark)

    Aartsen, M.G.; Abbasi, R.; Ackermann, M.

    2015-01-01

    of computational resources. IceProd is a distributed management system based on Python, XML-RPC and GridFTP. It is driven by a central database in order to coordinate and admin- ister production of simulations and processing of data produced by the IceCube detector. IceProd runs as a separate layer on top of other...

  8. 2006 Program of Study: Ice

    Science.gov (United States)

    2007-03-01

    form a debris flow. One such debris flow, initiated by a glacial lake flood in Peru in 1941, devastated the city of Huaraz, killing over 6000 people [5...ice, a series of’ prototype interlocking fingers is formed which grow ats the ice floes areI compressed and the ice floes plough through one another

  9. Polar Ice Caps: a Canary for the Greenland Ice Sheet

    Science.gov (United States)

    Honsaker, W.; Lowell, T. V.; Sagredo, E.; Kelly, M. A.; Hall, B. L.

    2010-12-01

    Ice caps are glacier masses that are highly sensitive to climate change. Because of their hypsometry they can have a binary state. When relatively slight changes in the equilibrium line altitude (ELA) either intersect or rise above the land the ice can become established or disappear. Thus these upland ice masses have a fast response time. Here we consider a way to extract the ELA signal from independent ice caps adjacent to the Greenland Ice Sheet margin. It may be that these ice caps are sensitive trackers of climate change that also impact the ice sheet margin. One example is the Istorvet Ice Cap located in Liverpool Land, East Greenland (70.881°N, 22.156°W). The ice cap topography and the underlying bedrock surface dips to the north, with peak elevation of the current ice ranging in elevation from 1050 to 745 m.a.s.l. On the eastern side of the ice mass the outlet glaciers extending down to sea level. The western margin has several small lobes in topographic depressions, with the margin reaching down to 300 m.a.s.l. Topographic highs separate the ice cap into at least 5 main catchments, each having a pair of outlet lobes toward either side of the ice cap. Because of the regional bedrock slope each catchment has its own elevation range. Therefore, as the ELA changes it is possible for some catchments of the ice cap to experience positive mass balance while others have a negative balance. Based on weather observations we estimate the present day ELA to be ~1000 m.a.s.l, meaning mass balance is negative for the majority of the ice cap. By tracking glacier presence/absence in these different catchments, we can reconstruct small changes in the ELA. Another example is the High Ice Cap (informal name) in Milne Land (70.903°N, 25.626°W, 1080 m), East Greenland. Here at least 4 unconformities in ice layers found near the southern margin of the ice cap record changing intervals of accumulation and ablation. Therefore, this location may also be sensitive to slight

  10. Polar Stereographic Valid Ice Masks Derived from National Ice Center Monthly Sea Ice Climatologies, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — These valid ice masks provide a way to remove spurious ice caused by residual weather effects and land spillover in passive microwave data. They are derived from the...

  11. Gastro-intestinal handling of water and solutes in three species of elasmobranch fish, the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate Raja eglanteria.

    Science.gov (United States)

    Anderson, W Gary; Dasiewicz, Patricia J; Liban, Suadi; Ryan, Calen; Taylor, Josi R; Grosell, Martin; Weihrauch, Dirk

    2010-04-01

    The present study reports aspects of GI tract physiology in the white-spotted bamboo shark, Chiloscyllium plagiosum, little skate, Leucoraja erinacea and the clear nose skate, Raja eglanteria. Plasma and stomach fluid osmolality and solute values were comparable between species, and stomach pH was low in all species (2.2 to 3.4) suggesting these elasmobranchs may maintain a consistently low stomach pH. Intestinal osmolality, pH and ion values were comparable between species, however, some differences in ion values were observed. In particular Ca(2+) (19.67+/-3.65mM) and Mg(2+) (43.99+/-5.11mM) were high in L. erinacea and Mg(2+) was high (130.0+/-39.8mM) in C. palgiosum which may be an indication of drinking. Furthermore, intestinal fluid HCO(3)(-) values were low (8.19+/-2.42 and 8.63+/-1.48mM) in both skates but very high in C. plagiosum (73.3+/-16.3mM) suggesting ingested seawater may be processed by species-specific mechanisms. Urea values from the intestine to the colon dropped precipitously in all species, with the greatest decrease seen in C. plagiosum (426.0+/-8.1 to 0mM). This led to the examination of the molecular expression of both a urea transporter and a Rhesus like ammonia transporter in the intestine, rectal gland and kidney in L. erinacea. Both these transporters were expressed in all tissues; however, expression levels of the Rhesus like ammonia transporter were orders of magnitude higher than the urea transporter in the same tissue. Intestinal flux rates of solutes in L. erinacea were, for the most part, in an inward direction with the notable exception of urea. Colon flux rates of solutes in L. erinacea were all in an outward direction, although absolute rates were considerably lower than the intestine, suggestive of a much tighter epithelia. Results are discussed in the context of the potential role of the GI tract in salt and water, and nitrogen, homeostasis in elasmobranchs.

  12. User's guide for ICE

    International Nuclear Information System (INIS)

    Fraley, S.K.

    1976-07-01

    ICE is a cross-section mixing code which will accept cross sections from an AMPX working library and produce mixed cross sections in the AMPX working library format, ANISN format, and the group-independent ANISN format. User input is in the free-form or fixed-form FIDO structure. The code is operable as a module in the AMPX system

  13. Autosub under ice

    OpenAIRE

    Griffiths, G.

    2005-01-01

    Autosub made headlines recently when it became trapped under 200m of ice in Antarctica.Here we explore the ideas behind the £5.86 million research programme, and look back at an earlier expedition which took place last summer off the coast of Greenland.

  14. Melting ice, growing trade?

    Directory of Open Access Journals (Sweden)

    Sami Bensassi

    2016-05-01

    Full Text Available Abstract Large reductions in Arctic sea ice, most notably in summer, coupled with growing interest in Arctic shipping and resource exploitation have renewed interest in the economic potential of the Northern Sea Route (NSR. Two key constraints on the future viability of the NSR pertain to bathymetry and the future evolution of the sea ice cover. Climate model projections of future sea ice conditions throughout the rest of the century suggest that even under the most “aggressive” emission scenario, increases in international trade between Europe and Asia will be very low. The large inter-annual variability of weather and sea ice conditions in the route, the Russian toll imposed for transiting the NSR, together with high insurance costs and scarce loading/unloading opportunities, limit the use of the NSR. We show that even if these obstacles are removed, the duration of the opening of the NSR over the course of the century is not long enough to offer a consequent boost to international trade at the macroeconomic level.

  15. Ecology under lake ice

    NARCIS (Netherlands)

    Hampton, Stephanie E.; Galloway, Aaron W. E.; Powers, Stephen M.; Ozersky, Ted; Woo, Kara H.; Batt, Ryan D.; Labou, Stephanie G.; O'Reilly, Catherine M.; Sharma, Sapna; Lottig, Noah R.; Stanley, Emily H.; North, Rebecca L.; Stockwell, Jason D.; Adrian, Rita; Weyhenmeyer, Gesa A.; Arvola, Lauri; Baulch, Helen M.; Bertani, Isabella; Bowman, Larry L., Jr.; Carey, Cayelan C.; Catalan, Jordi; Colom-Montero, William; Domine, Leah M.; Felip, Marisol; Granados, Ignacio; Gries, Corinna; Grossart, Hans-Peter; Haberman, Juta; Haldna, Marina; Hayden, Brian; Higgins, Scott N.; Jolley, Jeff C.; Kahilainen, Kimmo K.; Kaup, Enn; Kehoe, Michael J.; MacIntyre, Sally; Mackay, Anson W.; Mariash, Heather L.; Mckay, Robert M.; Nixdorf, Brigitte; Noges, Peeter; Noges, Tiina; Palmer, Michelle; Pierson, Don C.; Post, David M.; Pruett, Matthew J.; Rautio, Milla; Read, Jordan S.; Roberts, Sarah L.; Ruecker, Jacqueline; Sadro, Steven; Silow, Eugene A.; Smith, Derek E.; Sterner, Robert W.; Swann, George E. A.; Timofeyev, Maxim A.; Toro, Manuel; Twiss, Michael R.; Vogt, Richard J.; Watson, Susan B.; Whiteford, Erika J.; Xenopoulos, Marguerite A.

    Winter conditions are rapidly changing in temperate ecosystems, particularly for those that experi-ence periods of snow and ice cover. Relatively little is known of winter ecology in these systems,due to a historical research focus on summer ‘growing seasons’. We executed the first global

  16. Ice shelf fracture parameterization in an ice sheet model

    Directory of Open Access Journals (Sweden)

    S. Sun

    2017-11-01

    Full Text Available Floating ice shelves exert a stabilizing force onto the inland ice sheet. However, this buttressing effect is diminished by the fracture process, which on large scales effectively softens the ice, accelerating its flow, increasing calving, and potentially leading to ice shelf breakup. We add a continuum damage model (CDM to the BISICLES ice sheet model, which is intended to model the localized opening of crevasses under stress, the transport of those crevasses through the ice sheet, and the coupling between crevasse depth and the ice flow field and to carry out idealized numerical experiments examining the broad impact on large-scale ice sheet and shelf dynamics. In each case we see a complex pattern of damage evolve over time, with an eventual loss of buttressing approximately equivalent to halving the thickness of the ice shelf. We find that it is possible to achieve a similar ice flow pattern using a simple rule of thumb: introducing an enhancement factor ∼ 10 everywhere in the model domain. However, spatially varying damage (or equivalently, enhancement factor fields set at the start of prognostic calculations to match velocity observations, as is widely done in ice sheet simulations, ought to evolve in time, or grounding line retreat can be slowed by an order of magnitude.

  17. Ice shelf fracture parameterization in an ice sheet model

    Science.gov (United States)

    Sun, Sainan; Cornford, Stephen L.; Moore, John C.; Gladstone, Rupert; Zhao, Liyun

    2017-11-01

    Floating ice shelves exert a stabilizing force onto the inland ice sheet. However, this buttressing effect is diminished by the fracture process, which on large scales effectively softens the ice, accelerating its flow, increasing calving, and potentially leading to ice shelf breakup. We add a continuum damage model (CDM) to the BISICLES ice sheet model, which is intended to model the localized opening of crevasses under stress, the transport of those crevasses through the ice sheet, and the coupling between crevasse depth and the ice flow field and to carry out idealized numerical experiments examining the broad impact on large-scale ice sheet and shelf dynamics. In each case we see a complex pattern of damage evolve over time, with an eventual loss of buttressing approximately equivalent to halving the thickness of the ice shelf. We find that it is possible to achieve a similar ice flow pattern using a simple rule of thumb: introducing an enhancement factor ˜ 10 everywhere in the model domain. However, spatially varying damage (or equivalently, enhancement factor) fields set at the start of prognostic calculations to match velocity observations, as is widely done in ice sheet simulations, ought to evolve in time, or grounding line retreat can be slowed by an order of magnitude.

  18. Autonomous Ice Mass Balance Buoys for Seasonal Sea Ice

    Science.gov (United States)

    Whitlock, J. D.; Planck, C.; Perovich, D. K.; Parno, J. T.; Elder, B. C.; Richter-Menge, J.; Polashenski, C. M.

    2017-12-01

    The ice mass-balance represents the integration of all surface and ocean heat fluxes and attributing the impact of these forcing fluxes on the ice cover can be accomplished by increasing temporal and spatial measurements. Mass balance information can be used to understand the ongoing changes in the Arctic sea ice cover and to improve predictions of future ice conditions. Thinner seasonal ice in the Arctic necessitates the deployment of Autonomous Ice Mass Balance buoys (IMB's) capable of long-term, in situ data collection in both ice and open ocean. Seasonal IMB's (SIMB's) are free floating IMB's that allow data collection in thick ice, thin ice, during times of transition, and even open water. The newest generation of SIMB aims to increase the number of reliable IMB's in the Arctic by leveraging inexpensive commercial-grade instrumentation when combined with specially developed monitoring hardware. Monitoring tasks are handled by a custom, expandable data logger that provides low-cost flexibility for integrating a large range of instrumentation. The SIMB features ultrasonic sensors for direct measurement of both snow depth and ice thickness and a digital temperature chain (DTC) for temperature measurements every 2cm through both snow and ice. Air temperature and pressure, along with GPS data complete the Arctic picture. Additionally, the new SIMB is more compact to maximize deployment opportunities from multiple types of platforms.

  19. Improved ice loss estimate of the northwestern Greenland ice sheet

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Wahr, J.

    2013-01-01

    We estimate ice volume change rates in the northwest Greenland drainage basin during 2003–2009 using Ice, Cloud and land Elevation Satellite (ICESat) laser altimeter data. Elevation changes are often reported to be largest near the frontal portion of outlet glaciers. To improve the volume change...... estimate, we supplement the ICESat data with altimeter surveys from NASA's Airborne Topographic Mapper from 2002 to 2010 and NASA's Land, Vegetation and Ice Sensor from 2010. The Airborne data are mainly concentrated along the ice margin and thus have a significant impact on the estimate of the volume...... change. Our results show that adding Airborne Topographic Mapper and Land, Vegetation and Ice Sensor data to the ICESat data increases the catchment-wide estimate of ice volume loss by 11%, mainly due to an improved volume loss estimate along the ice sheet margin. Furthermore, our results show...

  20. Heterogeneous ice nucleation

    Energy Technology Data Exchange (ETDEWEB)

    Bogdan, A. [Helsinki Univ. (Finland). Dept. of Physics

    1994-12-31

    The classical theory of heterogenous ice nucleation is reviewed in detail. The modelling of ice nucleation in the adsorbed water films on natural particles by analogous ice nucleation in adsorbed water films on the walls of porous media is discussed. Ice nucleation in adsorbed films of purewater and the HNO{sub 3}/H{sub 2}0 binary system on the surface of porous aerosol (SiO{sub 2}) was investigated using the method of NMR spectroscopy. The median freezing temperature and freezing temperature region were shown to be highly sensitive both to the average thickness of the adsorbed films and to the amount of adsorbed nitric acid. The character of the ice phase formation tends to approach that of bulk liquid with increasing adsorbed film thickness. Under the given conditions the thickness of the adsorbed films decreases with an increasing amount of adsorbed nitric acid molecules The molar concentration of nitric acid in the adsorbed films is very small (of the order of 10{sup -}3 10{sup -}2 (M/l)). Nitric acid molecules tend to adsorb on the surface of aerosol to a greater extent than in subsequent layers. The concentration is greatest in layers situated close to the surface and sharply decreases with the distance from the surface. The difference between the median freezing temperatures for adsorbed pure water and for the binary system was found to be about 9 K for films of equal thickness. This is about 150 times greater than the difference between the median freezing temperatures of bulk pure water and a solution with the same concentration of nitric acid. (orig.)