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The purpose of the stratification is to group stands basing on the homogeneity of the measured feature. During periodic forest inventory in Poland, strata are created on the basis of age and the main species in stand within the boundary of forest district. In this work an improvement of distinguishing the strata during the forest inventory is presented. Three variants are considered: (1) distinguishing homogeneous strata in boundary of the whole forest district, not separately in forest subdistricts, (2) splitting species−aged strata into homogeneous substrata with respect to site quality, and (3) dividing strata of stands in the regeneration class with respect to stand density. Study was conducted in four mountain forest districts located in the Kłodzko Basin (SW Poland). Total area of these stands amounted to 43,052 ha, where 6,648 sample plots were established during the periodic inventory. ANOVA was used to test significance of the differences in tree volume and to assess variability reducing in distinguished substrata. Results indicated that in stands with age up to 70 years mean volume of trees on the sample plot does not differ significantly between sites, but in older stands difference was significant. Dividing age−species strata of stands older than 70 years into substrata according to site conditions influenced reduction of volume variability from 10 to 57% in newly created substrata. Dividing strata consisted of stands in regeneration class according to stand density index allowed to decrease the volume variability from 9 to 20%. Mean volume of trees in stands on similar sites does no differ significantly between subdistricts in the same forest district. Strata distinguished within the whole forest district are bigger and represented by more sample plots than on the subdistrict level, which significantly reduced standard error of volume and improved effectiveness of stratification in forest inventory.
Statistical representative method of inventory based on stratified sampling is used for elaborate forest management plans in Poland. Strata are created according to the dominant tree species and age of stands. First stratum include stands with age from 21 to 30 years and the interval in the next strata is 10 years. Sample plot size depends on stand age and varies from 0.005 to 0.05 ha. According to the allocation pattern number of samples is proportional to age and total area of stands in a stratum. Diversification of number and size of sample plots has a profound influence of inventory precision in an age classes. The aim of the study is to analyse the accuracy of the stand volume determination on the level of age−species strata. Research was conducted based on the data obtained from periodic forest inventory in seven mountainous forest subdistricts located in the Kłodzko Basin (SW Poland). Norway spruce stands with total area of 39,935.45 ha and 6102 sample plots were chosen for analysis. Sampling fraction, mean number and volume of trees on a sample plot, coefficient of volume variability and standard error of volume were calculated for each stratum in analyzed forest subdistricts. Sample plots with size of 0.005 ha established in young stands (21−30 years) are characterized by small number of trees (4.3−7.6 in average) and the highest coefficient of volume variability (93%). Additionally, because of low age of stands, the number of plots is also small (18 on average), which influences the low precision of volume inventory in this stratum. Standard error of volume was on the mean level of 23% in the youngest age stratum and decreased with age of stands to 5% in the stands of 41−71 years and below this level in the strata with the older stands. Increasing the plot size in the youngest stratum will be effective way to improve accuracy of forest inventory in the method based on stratified sampling.
The goal of this study was to determine the frequency of anomalies in incisor teeth depending on the horse’s age, sex, diet, diseases and floating frequency. A total of 255 horses from three Polish voivodeships, Kuyavian-Pomeranian, Greater Poland and Upper Silesia, were examined. The testing of incisor teeth was non-invasive and protocol-based. The most common defects were sharp edges of incisors in the maxilla and mandible, as well as a shortened mandible in relation to the maxilla. A relationship was proved between incisor anomalies and the horses’ age, floating frequency and bad habits. Anomalies of incisors are a common problem in horses in Poland, but they do not cause serious problems in the use of these animals.
The study describes a new method of assessing the average age of the forest range with significant share of stands in the regeneration class. In proposed method, average age of stands in regeneration layer is calculated as a mean age of tree layer as well as layer of upgrowth, recruitment and saplings weighed by these layers fraction. Example of calculation of average age was performed for 7 ranges located in Kotlina Kłodzka (SW Poland) with total area of 48 653 ha. Average age of stands calculated by proposed method vary from 62 to 73 years and is lower in comparison to average age calculating according to current regulations from 5 to 14 years. Proposed method of calculation the average age of stands in shelter wood cutting system takes into account composed structure of stands in regeneration period by using age and share of all trees generation in stand.
Speed skating is a competitive form of ice skating in which the athletes race each other at distances from 500 to 10000 m. In speed skating the main components of specific fitness include acceleration, anaerobic sprint ability and explosive power of the lower extremities. A specific starting pattern in speed skating affects the relationships between strength of individual muscle groups. The main aim of this study was to analyse the pattern of internal structure of specific speed skating movements depending on their velocity – % PSE. The study examined six female athletes from the Polish National Speed Skating Team. The results of muscle activity index (4/7 and 4/10 PES mean) revealed statistically significant differences for the GM (Z=2.36; p=0.017), A (Z=2.02; p=0.04) and BF (Z=2.20; p=0.027) muscles respectively. The same analysis was performed for differences between peak activities at intensities of 4/7 PES and 4/10 PES. The results revealed statistically significant differences for the TFL (Z=2.52; p=0.011) and A (Z=2.20; p=0.027) and BF (Z=2.36; p=0.017) muscles. The results obtained in this study show that the more effective use of Gluteus Medius (GM), Adductor (A), Biceps Femoris (BF) and Tensor Fasciae Latae (TFL) muscles substantially improves starting speed in speedskating.
Introduction. Luge is a winter Olympic sport. The level of performance in luge depends on the cumulative time of runs (typically two) performed on the track. The fastest times of the best male lugers on the Königssee luge track in Germany are around 49 seconds, with the speeds reaching 140 km per hour. Aim of Study. The aim of the present study was to examine the pattern of internal movement structure of the push and paddle phases of the luge start in a group of Polish national elite lugers, with regard to the speed at which these motor tasks are performed. Material and Methods. The study examined the performance of six male members of the Polish National Luge Team. The study participants were randomized. The study was carried out on the Königssee luge track in Germany. The lugers’ motor activity was measured in six muscles: anterior deltoid (AD), biceps brachii (BB), triceps brachii (TB), latisimuss dorsi (LD), flexor carpi ulnaris (FCU), and trapezius (T). Results. The repeated measures ANOVA for peak muscle activity between two speeds of the push phase revealed statistically significant intragroup differences for the TB (F = 21.232; p = 0.001) and LD (F = 23.412; p = 0.001) muscles. The paddle phase revealed statistically significant intragroup differences for the LD (F = 34.121; p = 0.001), T (F = 22.111; p = 0.001) and TB (F = 19.211; p = 0.001). Conclusions. The results of the study show that a more effective use of the latisimuss dorsi, triceps brachii and trapezius muscles substantially improves the speed of the luge start.
Background: The aim of study was to evaluate the effect of kinaesthetic differentiation during the in-run position on the in-run speed and jump length in ski-jumping team. Material and methods: The examinations were conducted on a group of 14 elite athletes from the A (n = 7) and B (n = 7) national ski-jumping team. The measurement of the angle of attack for an athlete maintaining the in-run position was made using the Zebris CMS 10 device for a precise and replicable analysis of spinal mobility. Results: Mean length of the jump in the team A was 97.16 (50,95 %) ± 2.78 for the first jump and 93.58 (49.05 %) ±4.23 for the second. In team B, jump length was 87.75 (51.27 %) for the first jump and 83.41 (48.73 %) ±5.77 for a second. The difference between the jump length of the 1st and 2nd jumps was a statistical significance at p < 0.05. Conclusions: In athletes from team B, lower angular deviations were observed in the in-run position, which means that these athletes were characterized by better reproduced position, whereas they adopted a relatively higher in-run position compared to athletes form team A.
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