This study investigated the explanatory power of a sensor fusion of two complementary methods to explain performance and its underlying mechanisms in ski jumping. A differential Global Navigation ...Satellite System (dGNSS) and a markerless video-based pose estimation system (PosEst) were used to measure the kinematics and kinetics from the start of the in-run to the landing. The study had two aims; firstly, the agreement between the two methods was assessed using 16 jumps by athletes of national level from 5 m before the take-off to 20 m after, where the methods had spatial overlap. The comparison revealed a good agreement from 5 m after the take-off, within the uncertainty of the dGNSS (±0.05m). The second part of the study served as a proof of concept of the sensor fusion application, by showcasing the type of performance analysis the systems allows. Two ski jumps by the same ski jumper, with comparable external conditions, were chosen for the case study. The dGNSS was used to analyse the in-run and flight phase, while the PosEst system was used to analyse the take-off and the early flight phase. The proof-of-concept study showed that the methods are suitable to track the kinematic and kinetic characteristics that determine performance in ski jumping and their usability in both research and practice.
Imitation jumps are frequently used in training for ski jumping. Yet, the dynamics of these jumps differ considerably. Thus, the relevance of imitation jumps for ski jumping performance is not ...elucidated. The aim of this study was to investigate the relationship between the technical execution of imitation jumps and ski jumping performance level. We compared the imitation jumps of 11 ski jumpers of different performance levels using a Spearman correlation transform of time traces of the kinetics (measured using force cells and motion capture) of imitation jumps. The kinetic aspects that were related to performance centred on the moment arm of ground reaction force to the centre of mass before the onset of the push-off, angular momentum early in push-off, thigh angle during the main period of push-off and vertical velocity towards the end of push-off. We propose that the thigh angle may be a key element allowing high development of linear momentum while preparing for appropriate aerodynamic position. Furthermore, the findings suggest that the kinetic development prior to (and during) push-off is more important than the kinematic end state at take-off.
We examined the effect of boundary conditions in imitation ski jumping on movement dynamics and coordination. We compared imitation ski jumps with - and without - the possibility to generate shear ...propulsion forces. Six elite ski jumpers performed imitation jumps by jumping from a fixed surface and from a rolling platform. The ground reaction force vector, kinematics of body segments, and EMG of eight lower limb muscles were recorded. Net joint dynamics were calculated using inverse dynamics. The two imitation jumps differed considerably from each other with regard to the dynamics (moments, forces), whereas the kinematics were very similar. Knee power was higher and hip power was lower on the rolling platform than on the fixed surface. Mean EMG levels were very similar for both conditions, but differences in the development of muscle activity were indicated for seven of eight muscles. These differences are reflected in a subtle difference of the alignment of ground reaction force with centre of mass: the ground reaction force runs continuously close to but behind the centre of mass on the rolling platform and fluctuates around it on the fixed surface. This likely reflects a different strategy for controlling angular momentum.
Interval breast cancer reduce the effectiveness of mammography screening programs. We studied 95 interval cancers, diagnosed
during 1996 to 2001 as part of the population-based Norwegian Breast ...Cancer Screening Program. These cases were matched on
size (±2.0 mm) to 95 screen-detected breast cancers, and the tumors were compared by immunohistochemical methods using tissue
microarrays. Patients with interval cancers were more likely to be younger odds ratio (OR), 4.7; P = 0.0001, to have dense breasts (OR, 3.4; P = 0.004), and to have estrogen receptor–negative tumors (OR, 2.6, P = 0.01), and p53 expression was more frequent (OR, 4.0; P = 0.001). Notably, interval cancers were more likely to have a basal epithelial phenotype, in that expression of cytokeratin
5/6 (OR, 2.3; P = 0.04) and P-cadherin (OR, 2.5; P = 0.04) was more frequent in interval cases than in size-matched, screen-detected tumors. In a logistic regression model,
p53 expression, age, and breast density were independent predictors of interval cancers. Our data suggest that breast cancers
with a basal epithelial phenotype are more likely than nonbasal breast cancers to present between regular mammograms.
Background
Transpulmonary passage of air emboli can lead to fatal brain‐ and myocardial infarctions. We studied whether pigs with open chest and pericardium had a greater transpulmonary passage of ...venous air emboli than pigs with closed thorax.
Methods
We allocated pigs with verified closed foramen ovale to venous air infusion with either open chest with sternotomy and opening of the pleura and pericardium (n = 8) or closed thorax (n = 16). All pigs received a five‐hour intravenous infusion of ambient air, starting at 4‐6 mL/kg/h and increased by 2 mL/kg/h each hour. We assessed transpulmonary air passage by transesophageal M‐mode echocardiography and present the results as median with inter‐quartile range (IQR).
Results
Transpulmonary air passage occurred in all pigs with open chest and pericardium and in nine pigs with closed thorax (56%). Compared to pigs with closed thorax, pigs with open chest and pericardium had a shorter to air passage (10 minutes (5‐16) vs. 120 minutes (44‐212), P < .0001), a smaller volume of infused air at the time of transpulmonary passage (12 mL (10‐23) vs.170 mL (107‐494), P < .0001), shorter time to death (122 minutes (48‐185) vs 263 minutes (248‐300, P = .0005) and a smaller volume of infused air at the time of death (264 mL (53‐466) vs 727 mL (564‐968), P = .001). In pigs with open chest and, infused air and time to death correlated strongly (r = 0.95, P = .001).
Conclusion
Open chest and pericardium facilitated the transpulmonary passage of intravenously infused air in pigs.
Background
Transpulmonary passage of air emboli can lead to fatal brain- and myocardial infarctions. We studied whether pigs with open chest and pericardium had a greater transpulmonary passage of ...venous air emboli than pigs with closed thorax.
Methods
We allocated pigs with verified closed foramen ovale to venous air infusion with either open chest with sternotomy and opening of the pleura and pericardium (n = 8) or closed thorax (n = 16). All pigs received a five-hour intravenous infusion of ambient air, starting at 4-6 mL/kg/h and increased by 2 mL/kg/h each hour. We assessed transpulmonary air passage by transesophageal M-mode echocardiography and present the results as median with inter-quartile range (IQR).
Results
Transpulmonary air passage occurred in all pigs with open chest and pericardium and in nine pigs with closed thorax (56%). Compared to pigs with closed thorax, pigs with open chest and pericardium had a shorter to air passage (10 minutes (5-16) vs. 120 minutes (44-212), P < .0001), a smaller volume of infused air at the time of transpulmonary passage (12 mL (10-23) vs.170 mL (107-494), P < .0001), shorter time to death (122 minutes (48-185) vs 263 minutes (248-300, P = .0005) and a smaller volume of infused air at the time of death (264 mL (53-466) vs 727 mL (564-968), P = .001). In pigs with open chest and, infused air and time to death correlated strongly (r = 0.95, P = .001).
Conclusion
Open chest and pericardium facilitated the transpulmonary passage of intravenously infused air in pigs.
New data regarding a positive association between smoking and risk of epithelial ovarian cancer (EOC), especially the mucinous tumor type, has started to emerge. The purpose of this study was to ...examine the association between different measures of smoking exposures and subtypes of EOC in a large cohort of women from 10 European countries. The European Prospective Investigation into Cancer and Nutrition (EPIC) cohort is a multicenter prospective study initiated in 1992. The questionnaires included data about dietary, lifestyle, and health factors. Information about cigarette smoking was collected from individuals in all participating countries. We used Cox proportional hazard regression models to estimate hazard ratio (HR) of EOC overall and serous, mucinous, and endometroid histological subtypes, with 95% confidence intervals (CIs) associated with different measures of smoking exposures adjusting for confounding variables. Altogether 836 incident EOC cases were identified among 326,831 women. The tumors were classified as 400 serous, 83 mucinous, 80 endometroid, 35 clear cell, and 238 unspecified. Compared with never smokers, current smokers had a significantly increased risk for mucinous tumors HR = 1.85 (95% CI 1.08–3.16) and those smoking more than 10 cigarettes per day had a doubling in risk HR = 2.25(95% CI 1.26–4.03) as did those who had smoked less than 15 pack‐years of cigarettes HR = 2.18 (95% CI 1.07–4.43). The results from the EPIC study add further evidence that smoking increases risk of mucinous ovarian cancer and support the notion that the effect of smoking varies according to histological subtype.
To retrospectively investigate whether different review designs have an influence on the estimate of missed interval cancer in a population-based breast cancer screening program.
The Norwegian Breast ...Cancer Screening Program invites women aged 50-69 years to undergo biennial screening mammography. The current study was part of the evaluation and scientific aspects of the screening program and thus was covered by the general ethical approval of the screening program as a part of the Cancer Registry of Norway. All participants signed an informed consent that specified that data related to their screening visit could be used for evaluation and scientific purposes. Six radiologists (9-34 years of experience in mammography) reviewed previously obtained bilateral two-view screening and diagnostic mammograms of 231 interval cancers, 117 screening-detected cancers, and 373 normal cases. Four review designs were used: individual and paired blinded review and individual and consensus informed review. A five-point interpretation scale was used to reclassify the cancers into missed cancers, minimal signs, and true cancers. The number and proportion of subgroups were estimated with 95% confidence intervals.
Of 231 interval cancers, 46 (19.9%) were reclassified as missed cancers with the mixed blinded individual review and 54 (23.4%) were classified as missed cancers with the mixed blinded paired review. Eighty-three cancers (35.9%) were classified as missed cancers with individual informed review, and 78 (33.8%) were classified as missed cancers with consensus informed review. Thirty-nine cancers (16.8%) were reclassified as missed when four or more radiologists assigned a score of 2 or more (probably benign or more suspicious); three cancers (1.3%) were reclassified as missed when a score of 4 or more (probably malignant or more suspicious) was assigned.
The percentage of interval cancers classified as missed ranged from 1.3% to 35.9% according to review design. To encourage learning, a review protocol should include both blinded and informed designs.
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