Carving

Using skis with a deep sidecut (as carving skis have it) it's not necessary to learn a new techniques. Different carving skis are developed for all target groups. They simplify the steering of turns on the ski-edge, but the skier needs some more muscle-effort as with usual skis. Lately physical researches proved that there's no higher risk of false cutting with carving skis than with common, normal sidecut skis. Mainly the condition of the ski-edge and the height of the skier's position over the ski do cause false cutting.     

Carving in comparison with ski technique of the skiing athlete (competitive skier) and the leisure and comfort level skier

In skiing there is principally no difference between the operating mechanism of a ski-racer and a skier who masters the technic of carving. Both try to ski with as less sliding as possible. The pressure distribution on the ski in a curve is very important. Near the end of the curve the pressure on the edge of the ski must be increased through various methods, on the one hand to avoid sliding and on the other hand to prepare the next curve correctly. In mastering the necessary mechanism of movements, the carving with the more wasted skis will be easier, because it is not necessary to put as much pressure on the last section of the ski, as it is necessary with the original skies to have the same result. Therefore even the holiday-skier has the possibility with carving-skis to master the ski-technic of the ski-racer and to have the pleasure of carving instead of sliding.     

Comparisons of the ski turn techniques of experienced and intermediate skiers

We compared selected kinematic variables for four different ski turn techniques performed by five experienced and five intermediate male skiers. The four ski turn techniques were the upstem turn, the downstem turn, the parallel turn and the parallel step turn. Each turn was divided into the initiation phase and the first and second steering phases. Most of the statistically significant differences (P < 0.05) between the two groups were found for the initiation phases of the four turns. Both the hip axis-hand axis angle and the edging angle of the uphill ski were significantly different between the two groups for the upstem turn at the beginning of the initiation phase. For the downstem turn, significant differences between the groups were found at the start of the initiation phase for the hip axis-hand axis angle, the shoulder axis-fall line angle, and the edging angle of the uphill ski. The standard deviation of the distance between the tips of the two skis over the second steering phase also differed significantly between the two groups. For the parallel step turn, significant differences were found at the start of the initiation phase for the edging angle of the downhill ski and the downhill ski to movement direction angle. Significant differences were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. For the initiation phase of the parallel turn, significant differences were found for the timing of setting the ski pole, the uphill knee angle at the start of this phase and the range of the knee angle of the uphill leg from the start to the end of this phase. For this turn, significant differences between the two groups were also found for the edging angle of the downhill ski in the middle of the second steering phase and the shoulder axis to movement direction angle at the end of this phase. One of the reasons it was possible to identify a few significant differences only for the turns analysed, was the variability within the intermediate group: for most of the variables analysed, the standard deviation was much higher for the intermediate than for the experienced group.     

Anterior cruciate ligament injury in elite Alpine competitors

Balance in Alpine skiing is dynamic and tenuous. Loss of balance typically leads to the accumulation of forces that create severe bending moments at the knee. The modern ski binding, while effective at protecting the ankle and lower leg, is much less effective at protecting the knee. The result: knee injuries have increased nearly three-fold since 1972 with anterior cruciate ligament (ACL) injuries currently accounting for approximately 10% of all skiing injuries. The mechanism of ACL injury in elite competitors is distinct from recreational skiers and is typically associated with a characteristic, deeply flexed, seated body position, with the feet accelerating forward relative to the upper body. The risk of ACL injury in elite skiers is compounded by the functional characteristics of the modern ski binding and further exacerbated by the protocols used to set release tension for competition. It is apparent that the physical abilities of the elite competitor, combined with modern ski technique and equipment, expose the skier to forces that the human body cannot tolerate. Presently, the only solution to the problem would appear to be the development of "smarter" bindings and/or the adoption of standards that set limitations on performance for the sake of safety.     

Genetic mapping of the mouse stromal cell-derived factor gene (Sdf1) to mouse and rat chromosomes

OBJECTIVE: To establish the demographics of ski injury in relation to age, gender, and perceived cause during a representative season to identify potential injury prevention strategies. SETTING: Blackcomb Mountain, a world class ski resort in British Columbia, Canada. METHODS: Data were collected from the lift ticket records and from ski patrol injury reports for one season, November to May 1991-2. RESULTS: There were 720,066 skier and snowboarder day visits counted by the mountain's lift ticket records, with a total of 2,092 injury reports (incidence 2.91 per 1,000 day visits). Of those with significant injuries (those requiring physician care), 1,210 (58%) were male. The highest injury rate was among children (age 7-12) and teens (age 13-17) with incidences of 3.18 and 3.34 significant injuries per 1,000 skier days, respectively. Head and face injuries constituted 17% and 22% of injuries, respectively in these groups. Overall 22% of head and face injuries were severe enough to cause loss of consciousness or clinical signs of concussion. This was the body region injured most frequently in males. For females over 7 years of age, the knee was the most common site of injury. For youths, the incidence of injuries during school organized activities was 25% higher than during other outings. CONCLUSIONS: The vulnerability of school group participants suggests special education is warranted. The high incidence of head injuries, particularly among young males, needs to be addressed. In light of the high proportion of this group who already wear helmets, the role of helmets in both protection and possible causation of head injury needs objective research.     

Acute lung injury after inhalation of water-proofing spray while smoking a cigarette

A 34-year-old Japanese woman developed acute lung injury soon after inhaling a water-proofing spray which she applied onto her ski suit while smoking a cigarette at the same time. She initially demonstrated arterial hypoxemia (PaO2 = 59 mm Hg) and ground-glass opacities in both lung fields on the CT scan, which both returned to normal without any medication. Several water-proofing sprays, which are easily obtainable in Japan, contain 1,1,1-trichloroethane, liquefied petroleum gas and fluoride resin. Although these components have not been reported to be toxic to the lung yet, high concentrations of these components and/or the pyrolytic products of fluoride resin may have caused acute lung injury in this case.     

Snowboarding injuries

Snowboarding is a popular winter sport that involves riding a single board down a ski slope or on a half-pipe snow ramp. Compared with injuries resulting from traditional alpine skiing, snowboarding injuries occur more frequently in the upper extremities and ankles and less frequently in the knees. Different types of snowboard equipment, rider stance and snowboarding activity tend to result in different types of injury. Snowboarder's ankle, a fracture of the lateral talus, must be considered in a snowboarder with a "severe ankle sprain" that has not responded to treatment. Risk of injury may be lowered by using protective equipment, such as a helmet and wrist guards.     

Ski Jump Hydraulics

Ski jumps are a major element of each dam spillway because these are the only structures able to accomplish satisfactory energy dissipation for takeoff velocities in excess of some 20?m/s. This research aims to add to several hydraulic problems with ski jumps that have not yet been systematically solved so far. Based on an experimental campaign, the following problems were addressed: (1) pressure head maximum and pressure distribution along a circular-shaped flip bucket; (2) takeoff characteristics for a certain bucket deflection and a relative bucket curvature including the jet trajectories of both the lower and the upper nappes; (3) impact characteristics in a prismatic tailwater channel with details of shock wave formation and height of recirculation depth; (4) energy dissipation across the ski jump, from the upstream channel to downstream of jet impact; and (5) choking flow conditions by the flip bucket. These results demonstrated the significant effect of the approach Froude number, the relative bucket curvature and the bucket angle. The results allow immediate application to the design of ski jumps in hydraulic engineering.     

Fine-needle aspiration biopsy of metastatic Ewing''s sarcoma with MIC2 (CD99) immunocytochemistry

A 16-year-old female was involved in a jet ski (water craft) accident resulting in bilateral lower extremity fractures but no loss of consciousness or any other evidence of head trauma. Thirty hours later she became comatose. Magnetic resonance imaging was consistent with diffuse axonal injury. She recovered after several weeks without any clinical sequelae. This patient demonstrates an unusual example of diffuse axonal injury without direct head trauma and with delayed onset of symptoms. The authors recommend that patients involved in high-velocity accidents, even without immediate evidence of head injury, be observed for signs of diffuse axonal injury.     

Cardiovascular effects of nepicastat (RS-25560-197), a novel dopamine beta-hydroxylase inhibitor

PURPOSE: The aim of the present study was to develop a standard protocol for evaluating peak oxygen uptake and anaerobic threshold during upper body work by cross-country skiers. METHODS: All tests were performed on a specially developed ski ergometer and incorporated the double poling technique. In series I, continuous and discontinuous protocols for measuring VO2peak at different inclinations of the ski ergometer were performed. In series II, a protocol for evaluating anaerobic threshold during upper body work was established. Eleven well trained regional male cross-country skiers participated in the study. All tests in each series were carried out during a period of 14 d. RESULTS: VO2peak did not differ using continuous or discontinuous protocol while working on the ski ergometer. Inclination was found to influence VO2peak, which was reduced at 7 degrees compared with 3 degrees, 5 degrees, and 6 degrees. Th(an) working on the ski ergometer was reached at a power output, VO2, or fc, which gave on average a blood lactate concentration of 1.8 mmol.L-1 higher than those found after the warm-up period during a graded protocol. CONCLUSIONS: Testing only the traditional Th(an) and VO2max while running on a treadmill hides important determinants of endurance in cross-country skiing as shown by that no correlation was found between VO2max and VO2peak in the present study.     

Aeration Characteristics of Ski Jump Jets

Scour downstream of ski jumps may be avoided by jet deflection to an area where the energy dissipation is accomplished. The main purpose of this experimental study was the analysis of the jet air entrainment downstream of a ski jump, both for pure water and preaerated approach flow conditions. A systematic variation of the Froude number and the flow depth in the approach flow channel resulted in a range of discharge characteristics, whereas the geometry of the ski jump was maintained for all tests. The air concentration profile was measured at different locations downstream from the ski jump to evaluate the: (1) jet air concentration distribution; (2) location of minimum air concentration along the mixture flow jet and development of the minimum and the cross-sectional average air concentrations; (3) jet trajectories; and (4) process of air entrainment characteristics and jet disintegration. The results demonstrate the significant effect of the approach flow Froude number, the approach flow depth, and of preaeration on jet disintegration.     

通信工程专业教学模式改革

通信技术的飞速发展对通信专业人才的培养提出了更高的要求。改革通信工程专业教学模式,构建个性化人才培养模式;优化课程结构,实行课程负责人制;建立导师指导制度,引导学生自主学习,鼓励学生自主创业;进行多层次、开放性实验教学,培养学生的实践能力和创新精神;加强校企合作,促进产、学、研一体化,以培养适应于信息化时代要求的高级通信专业人才。     

Effect of ski tapering on turning radius and stress

The first part of this paper deals with the influence of the side cut on the turn radius, which was examined by measuring the turn radius of a self-running sledge-like construction and by comparing it to Howe's prediction. The turn radius at the beginning of the turn has proved to be between 65 and 85% of the theoretically expected result. In the second part a carvers turn radius was determined and the reaction force acting on the skier was calculated. The result shows a strong reduction of the turn radius along the path which increases the load on the skier. The effect of side cut and velocity on the load was examined. Using carver skis even small changes in velocity resulted in considerable load changes.     

Association between somatic symptoms and 24-hour ambulatory blood pressure levels

A wide variety of irritants can lead to respiratory failure after inhalation injuries. We present a case of adult respiratory distress syndrome after exposure to a fluorocarbon resin (PFF 1020) used as ski wax. The patient sustained a mild but prolonged exposure to this substance, which subsequently led to symptoms of severe respiratory failure over the next 24 hours. Except for hypocalcemia, there were no systemic manifestations and recovery was uneventful. Ski wax is considered to be nontoxic and there are no reported side effects of these products. Injury was related to the heated fluorocarbon particles. This case report of a severe lung inhalation injury points out the increasing risk of environmental hazards associated with the use of synthetic substances.     

Debris- and Ice-Skimming Booms at Riverside Diversions

Hydraulic-design guidelines are presented for deploying debris- and ice-skimming booms at riverside diversions such as water intakes for thermal power stations, municipal water-supply facilities, and irrigation canals. Based on laboratory-flume tests and boom literature, the guidelines aim to reduce debris passage into and accumulations at diversions. Important design variables include boom distance out from the diversion entrance, boom orientation to the diversion, and boom draft. Optimal deployment of skimming booms is related to the flow field at riverside diversions. The flume tests established how these variables influence the physical processes governing skimming-boom performance, and they led to recommendations on effective deployment of straight and bent booms for debris flushing. Bent booms, which comprise two segments (one angled from upstream and one parallel to the diversion), are the more effective boom type for wider ranges of river and diversion flows.     

Deflector Ski Jump Hydraulics

Ski jumps are a standard element of dam spillways for an efficient energy dissipation if takeoff velocities are large, and stilling basins cannot be applied. This laboratory study investigates the hydraulic performance of a triangular-shaped, rather than the conventional circular-shaped, bucket placed at the takeoff of ski jumps. The following items were addressed: (1) pressure head maximum and pressure distribution along the triangular-shaped bucket; (2) takeoff characteristics as a function of the bucket deflector angle and the relative bucket height including the lower and the upper jet trajectories; (3) jet impact characteristics in a prismatic tailwater channel including the shock wave formation and the height of recirculation depth below the jet cavity; (4) energy dissipation across the ski jump, from the approach flow channel to downstream of jet impact; and (5) choking flow conditions of the flip bucket. A significant effect of the approach flow Froude number, the relative bucket height, and the deflector angle is found. A comparison with previous results for the circular-shaped bucket geometry indicates a favorable behavior of the novel bucket design.     

Evaluation of alpine skiing and snowboarding injury in a northeastern state

BACKGROUND: To demonstrate the injury patterns of Alpine skiing and snowboarding in a northeastern state and evaluate potential risk factors. METHODS: The medical records of a single pediatric and adult Level I trauma center were evaluated from January 1, 1990, through December 31, 1995. All admissions with injuries caused by Alpine skiing or snowboarding were reviewed. Those patients arriving from two local ski resorts, all of whose injuries are referred to the institution for care, were separated out for consideration. Age, sex, type of injury, date of injury, Injury Severity Score, operations performed, and outcome (including mortality) were evaluated. In addition, resort utilization for the study period was obtained from the two resorts included in the evaluation. Mortality data was obtained from the Vermont office of the Chief Medical Examiner for the same time period. RESULTS: For the 6-year period of the study approximately 2,978,000 skier and snowboarder days were recorded at the study sites. Approximately 447,000 of those days were attributed to snowboarders (15%). In all, 279 patients were admitted for injuries (0.01%), 238 were related to Alpine skiing (incidence 0.01%) and 40 to snowboarding (incidence 0.01%). Snowboarders were statistically younger (20 years; range, 4-44 years) than skiers (29 years; range, 6-70 years) (p < 0.001) and had a significantly lower Injury Severity Score (15 in snowboarders vs. 27 in skiers, p < 0.03). Two female patients were injured snowboarding and 68 female patients were injured skiing. Eight percent of injured snowboarders and 16% of injured skiers sustained multiple injuries (p < 0.01). Injury patterns were significantly different. Upper extremity injuries were almost exclusively found in snowboarders (24% vs. 7%, p < 0.003), whereas cruciate ligament injuries occurred far more commonly in skiers (45% vs. 4%, p < 0.001 Lower extremity injuries in general were more common in skiers (78% vs. 38%, p < 0.001). Central nervous system injuries, including head and spine, were evenly distributed over the two groups, although the snowboarders with central nervous system injuries were younger. In addition, splenic injuries were more common in snowboarders (13% vs. 2%, p < 0.01). Snowboarding accidents were far more common in December, March, and April than other months. Fifty-one patients sustained abdominal or chest injuries and only two of these required operative intervention (two splenectomies). Other operative interventions were limited to extremity injuries, injuries of the spine, or placement of an intracranial pressure monitor. There were no fatalities recorded in this population, although over the 6.5 years, there were 25 deaths related to alpine skiing and one to snowboarding in the State (incidence 0.0000009 skier days). Victims tended to be male: 96% of the skiers and the one snowboarder. The predominant cause of death was blunt head trauma followed by blunt chest trauma. Helmets were not worn by those sustaining head injuries or fatalities. Spine injuries were recorded only in extremely young snowboarders and skiers out of control. CONCLUSION: Snowboarders and Alpine skiers are equally prone to injury. Snowboarding accidents are typically less severe and show significantly different injury patterns than skiing accidents. Abdominal and chest injuries in this population are generally amenable to nonoperative management. Prevention programs are best targeted at safe skiing and snowboarding practices, not skiing or snowboarding in poor conditions, use of helmets for skiers, and restraint of snowboard use in very young children.     

Traumatic head injury: A challenge to rehabilitation psychologists.

Traumatic head injury is a tragedy for all whom it affects. Many families of injured individuals report that the most painful aspects of the injury are the lack of accurate information available to them at all points following the injury and the fact that, because a head injury's effects are so different from those of other illnesses and injuries, no one seems to understand. It is hoped that this Special Issue of Rehabilitation Psychology will not only help more people to understand, but will also impel some readers to participate in the search for answers. In pulling these papers together, I struggled with the question of whether to include papers from the wide spectrum of rehabilitation efforts in which psychologists are involved (including neuropsychological assessment, cognitive retraining, vocational rehabilitation, etc.), or to focus on one major area. Given the increasing number of books that provide the broader perspective, I have chosen the latter route, including papers dealing with the psychosocial issue that is a prerequisite for success in other areas—how patients and their families come to terms with the injury and its consequences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)