The relationship between velocity utilization rate and pole vault performance

In the pole vault event, the velocity of approach is a highly vital factor. As velocity of approach improvements highly impact performance improvements. This study analysed the relationships between sprint running’s speed (SR), pole running (PR, without jump), and the pole vault approach (PVA, with real jump). Analysed too were the relationships between both the approach and performance’s respective running distance, velocity, and velocity utilization rates. Methods: Ten male pole vaulters were recruited. Measured was each 5-meter segment’s average velocity of his respective SR, PR, and PVA, along with the distance to maximum velocity. Results: The maximum average velocity of the PR’s 5m segments altogether was significantly positively correlated with pole vault (PV) performance; The maximum average velocity of the PR’s 5m segments altogether was significantly positively correlated with the last 5m PVA average velocity; The PVA velocity’s utilization rate was significantly negatively correlated with the difference between the distance to the PR’s maximum velocity and the PVA’s distance. Conclusion: The PR segment’s maximum speed capability can evaluate both a pole vaulter’s potential and pole vault-specific abilities. This study’s recruited pole vaulters’ respective approach distances were generally insufficient that resulted in a lower velocity utilization rate. Suggested is that in training, the pole vaulter could first find the distance required to reach the highest velocity upon starting from the PR test. Thus, this subsequently known distance could be applied in tandem with the pole vault’s approach to both improve the PVA’s utilization rate and reach the individual highest speed level

Sampling for area estimation: A comparison of full-frame sampling with the sample segment approach

The effect of sampling on the accuracy (precision and bias) of crop area estimates made from classifications of LANDSAT MSS data was investigated. Full-frame classifications of wheat and non-wheat for eighty counties in Kansas were repetitively sampled to simulate alternative sampling plants. Four sampling schemes involving different numbers of samples and different size sampling units were evaluated. The precision of the wheat area estimates increased as the segment size decreased and the number of segments was increased. Although the average bias associated with the various sampling schemes was not significantly different, the maximum absolute bias was directly related to sampling unit size

Effect of season, explants, growth regulators and sugar level on induction and long term maintenance of callus cultures of Ficus religiosa L.

The effects of antioxidant treatments, 2,4-D concentrations and sucrose level were examined in order to optimize the induction and long term maintenance of callus cultures of Ficus religiosa L. from different explants including nodal segments, inter-nodal segments and shoot apices. The explants subjected to incubation for 40 min in antioxidant solution (2% ascorbic acid + 2% citric acid) exhibited maximum percent culture establishment (73.33%). Establishment was reduced when incubation time was longer than 40 min. The explants collected in May and June gave maximum response (100 %). The highest frequency of callus induction (100%) was observed in nodal segments on Murashige and Skoog medium supplemented with 2.26 μM 2,4-dichlorophenoxyacetic acid and 3% sucrose after an average of 8.38 days. Maximum callus proliferation, resulting in fresh weight of 4.29 g after four weeks of culture, was also observed for callus initiated from nodal segments on the earlier mentioned medium. Higher concentrations of 2,4-D and lower concentrations of sucrose were found to be unfavourable for callus induction as well as proliferation. Callus cultures, initiated from nodal segments, could be  successfully maintained in healthy and proliferative form for consecutive nine months on the earlier said medium.Key words: Ficus religiosa L., explants, callus induction, callus proliferation,callus maintenance, in vitro

Separating atrial near fields and atrial far fields in simulated intra-Atrial electrograms

The detailed characterization of complex forms of atrial flutter relies on the correct interpretation of intra-atrial electrograms. For this, the near fieldcomponents, which represent the local electrical activity, are decisive. However, far field components arising from distant electrical sources in the atria can obscure the diagnosis.We developed a method to separate and characterize atrial near field and atrial far field components from bipolar intra-atrial electrograms. First, a set of bipolar electrograms was created by simulating different propagation scenarios representing common clinical depolarizationpatterns. Second, near and far fields were detected as active segments usinga non-linear energy operator-based approach. Third, the maximum slope and the spectralpower were extracted as features for all active segments. Active segments were grouped accounting for both the timing and the location of their occurrence. In a last step, the active segments were classified in near and far fields by comparing their feature values to a threshold.All active segments were detected correctly. On average, near fields showed 15.1x larger maximum slopes and 40.4x larger spectral powers above 100 Hz than far fields. For 135 active segments detected in 72 bipolar electrograms, 5.2% and 6.7% were misclassified using the maximum slope and the spectral power, respectively. All active segments were classified correctly if only one near field segment was assumed to occur per electrogram.The separation of atrial near andatrial far fields was successfully developed and applied to in silico electrograms.Theseinvestigations providea promising basis fora future clinical study to ultimatelyfacilitatethe precise clinical diagnosis of atrial flutter

Evaluation of fine root length and diameter measurements obtained using RHIZO image analysis

Image analysis systems facilitate rapid measurement of root length and diameter, but their accuracy is not easily determined. The objective of this study was to develop a set of simple experiments for evaluating the accuracy of fine root measurements obtained using image analysis. Using the system RHIZO (trademark of Regent Instruments, Quebec), we tested the accuracy of (i) length measurements made over a range of root lengths per unit area, (ii) average diameter measurements and length per diameter distributions in string, wire, and fine root samples of varying diameter, and (iii) diameter measurements on short segments of diagonally oriented objects. Our results suggest that preliminary testing of image analysis systems is absolutely necessary for producing reliable root measurements. Total length was accurately determined for typically encountered length per unit areas of <1.5cm cm-2. For samples with higher values, however, the method underestimated total length by >5%. It is therefore recommended that users of image analysis systems determine this maximum length per unit area for accurate determinations of total root length. In samples that contained different string diameters, the total sample length and average string diameter could accurately be measured. However, the length per diameter class was underestimated by >20% when the string diameter was less than one pixel smaller than the upper limit of the diameter class. Adjustment of diameter intervals and increasing the scanner resolution are required to reduce this underestimation. Both the length and the angle of the short segments analyzed were found to influence diameter measurements. Similar sets of experiments are proposed for a rigorous evaluation of the performance of other image analysis systems on root measurements

Classification of the Alaskan Beaufort Sea Coast and estimation of carbon and sediment inputs from coastal erosion

A regional classification of shoreline segments along the Alaskan Beaufort Sea Coast was developed as the basis for quantifying coastal morphology, lithology, and carbon and mineral sediment fluxes. We delineated 48 mainland segments totaling 1,957 km, as well as 1,334 km of spits and islands. Mainland coasts were grouped into five broad classes: exposed bluffs (313 km), bays and inlets (235 km), lagoons with barrier islands (546 km), tapped basins (171 km) and deltas (691 km). Sediments are mostly silts and sands, with occasional gravel, and bank heights generally are low (2–4 m), especially for deltas (<1 m). Mean annual erosion rates (MAER) by coastline type vary from 0.7 m/year (maximum 10.4 m/year) for lagoons to 2.4 m/year for exposed bluffs (maximum 16.7 m/year). MAERs are much higher in silty soils (3.2 m/year) than in sandy (1.2 m/year) to gravelly (−0.3 m/year) soils. Soil organic carbon along eroding shorelines (deltas excluded) range from 12 to 153 kg/m2 of bank surface down to the water line. We assume carbon flux out from depositional delta sediments is negligible. Across the entire Alaskan Beaufort Sea Coast, estimated annual carbon input from eroding shorelines ranges from –47 to 818 Mg/km/year (Metric tones/km/year) across the 48 segments, average 149 Mg/km/year (for 34 nondeltaic segments), and total 1.8×105 Mg/year. Annual mineral input from eroding shorelines ranges from −1,863 (accreting) to 15,752 Mg/km/year, average 2,743 Mg/km/year, and totals 3.3 ×106 Mg/year

Load displacement behavior of the human Lumbo-sacral joint

The three-dimensional load displacement behavior of nine fresh adult L5-S1 spine motion segments was studied. Static test forces up to 160 N in anterior, posterior, and lateral shear, test forces up to 320 N in compression, and test moments up to 15.7 Nm in flexion, extension, lateral bending, and torsion were used. The six displacements of the center of the inferior L5 endplate were measured 15 and 60 s after the load was applied. Specimens were then retested after posterior element excision. The results show that at the maximum test force, intact specimen mean (sd) displacements ranged from 1.65 mm (0.63 mm) in lateral shear to 2.21 mm (0.87 mm) in posterior shear. Posterior element excision resulted in an average 1.66-fold increase in shear translations. At the maximum moment, rotations ranged from 3.38° (1.03°) in torsion to 7.19° (1.77°) in flexion. Posterior element excision resulted in an average 2.09-fold increase in bending rotations and a 2.74-fold increase in the average torsional rotation. In general, these L5-S1 joints were stiffer than more cranial lumbar segments in flexion, extension, and lateral bending and were less stiff in torsion tests.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50380/1/1100050404_ftp.pd

Kinematic Patterns Associated with the Vertical Force Produced during the Eggbeater Kick

The purpose of this study was to determine the kinematic patterns that maximized the vertical force produced during the water polo eggbeater kick. Twelve water polo players were tested executing the eggbeater kick with the trunk aligned vertically and with the upper limbs above water while trying to maintain as high a position as possible out of the water for nine eggbeater kick cycles. Lower limb joint angular kinematics, pitch angles and speed of the feet were calculated. The vertical force produced during the eggbeater kick cycle was calculated using inverse dynamics for the independent lower body segments and combined upper body segments, and a participant-specific second degree regression equation for the weight and buoyancy contributions. Vertical force normalized to body weight was associated with hip flexion (Average, r=0.691; Maximum, r=0.791; Range of Motion, r=0.710), hip abduction (Maximum, r=0.654), knee flexion (Average, r=0.716; Minimum, r=0.653) and knee flexion-extension angular velocity (r=0.758). Effective orientation of the hips resulted in fast horizontal motion of the feet with positive pitch angles. Vertical motion of the feet was negatively associated with vertical force. A multiple regression model comprising the non-collinear variables of maximum hip abduction, hip flexion range of motion and knee flexion angular velocity accounted for 81% of the variance in normalized vertical force. For high performance in the water polo eggbeater kick players should execute fast horizontal motion with the feet by having large abduction and flexion of the hips, and fast extension and flexion of the knees

Determining the best sectioning method and intestinal segment for morphometric analysis in broilers

Brazilian poultry production is very efficient and demands maximum broiler performance. Therefore, digestive system pathologies have a relevant role. Considering it is difficult to obtain consistent information on intestinal morphometric analysis, this study aimed at establishing essential and clear criteria for the collection of intestinal segments for morphometric analysis. Fifteen 13-d-old broilers were sacrificed and three intestinal segments were collected per bird. Two 3-cm long sections were obtained from each of the intestinal segments. Samples were collected open or closed. The closed samples were transversely, hemicylindrically, or longitudinally sectioned. Samples were processed and stained with hematoxylin and eosin. The number of microscopic fields in each section was counted. Villi presenting the base clearly embedded in the submucosa, no damage or folds, and simple columnar epithelium at the tip were considered adequate for measurements. These villi were counted in each sample. The results shows that hemicylindrical sections presented the highest number of observation fields, with an average of 9.76 fields. Jejunum samples were among the three highest average villi counts, with 18.23 in longitudinal sections and 15.61 in hemicylindrical sections. The results of the present study indicate that hemicylindrical sectioning and jejunal samples were, respectively, the best sectioning method and the best intestinal segment for the morphometric analysis of the intestines of broilers

Fluctuation Properties of Steady-State Langevin Systems

Motivated by stochastic models of climate phenomena, the steady-state of a linear stochastic model with additive Gaussian white noise is studied. Fluctuation theorems for nonequilibrium steady-states provide a constraint on the character of these fluctuations. The properties of the fluctuations which are unconstrained by the fluctuation theorem are investigated and related to the model parameters. The irreversibility of trajectory segments, which satisfies a fluctuation theorem, is used as a measure of nonequilibrium fluctuations. The moments of the irreversibility probability density function (pdf) are found and the pdf is seen to be non-Gaussian. The average irreversibility goes to zero for short and long trajectory segments and has a maximum for some finite segment length, which defines a characteristic timescale of the fluctuations. The initial average irreversibility growth rate is equal to the average entropy production and is related to noise-amplification. For systems with a separation of deterministic timescales, modes with timescales much shorter than the trajectory timespan and whose noise amplitudes are not asymptotically large, do not, to first order, contribute to the irreversibility statistics, providing a potential basis for dimensional reduction.Comment: 8 pages, to be published in Physical Review