scholarly journals Uncertainty caused by resistances in evapotranspiration

2019 ◽  
Author(s):  
Wen Li Zhao ◽  
Yu Jiu Xiong ◽  
Kyaw Tha Paw U ◽  
Pierre Gentine ◽  
Baoyu Chen ◽  
...  
Keyword(s):  
Surface Resistance ◽  
Aerodynamic Resistance ◽  
Northwest China ◽  
Mean Absolute Percent Error ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Impact ◽  
Absolute Percent Error ◽  
Better Than

Abstract. Quantifying the uncertainties induced by resistance parameterization is fundamental to understanding, improving, and developing terrestrial evapotranspiration (ET) models. Using high-density eddy covariance (EC) tower observations in a heterogeneous oasis in Northwest China, this study evaluates the impact of resistances on latent heat flux (LE) estimations, the energy equivalent of ET, by comparing resistance parameterizations with varied complexity under one- and two-source Penman-Monteith (PM) equations. We then discuss possible solutions for reducing such uncertainties by employing a three-temperature (3T) model, which does not explicitly include resistance-related parameters. The results show that the mean absolute percent error (MAPE) varied from 32 % to 39 % for the LE estimates from the one- and two-source PM equations. When only surface resistance (rs) was parameterized under the one-source network, then the uncertainty (defined as the difference between MAPEs) dropped to 12 %. When both rs and aerodynamic resistance (ra) were parameterized differently under the one- and two-source networks, then the uncertainties in the estimates were 11~23 %, emphasizing that multiple resistances add uncertainties. Additionally, the 3T model performed better than the PM equations, with MAPE of 19 %. The results suggest that 1) although prior calibration of the parameters required in resistance estimations can improve the PM-based LE estimates, resistance parameterization process can generate obvious uncertainties, 2) more complex resistance parameterizations leads to more uncertainty in the LE estimation, and 3) the relatively simple 3T model avoids resistance parameterization, thus introducing less uncertainty in the LE estimation.

Uncertainties Caused by Resistances in Evapotranspiration Estimation Using High-Density Eddy Covariance Measurements

2020 ◽  
Vol 21 (6) ◽  
pp. 1349-1365 ◽  
Author(s):  
Wen Li Zhao ◽  
Guo Yu Qiu ◽  
Yu Jiu Xiong ◽  
Kyaw Tha Paw U ◽  
Pierre Gentine ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Northwest China ◽  
High Density ◽  
Biophysical Parameters ◽  
Mean Absolute Percent Error ◽  
Eddy Covariance Measurements ◽  
The Mean ◽  
Evapotranspiration Estimation ◽  
The One ◽  
Absolute Percent Error

AbstractQuantifying the uncertainties caused by resistance parameterizations is fundamental for understanding, improving, and developing terrestrial evapotranspiration (ET) models. Using high-density eddy covariance (EC) tower observations in a heterogeneous oasis in northwest China, this study evaluates the impacts of resistances on the estimation of latent heat flux (LE), the energy equivalent of ET, by comparing resistance parameterizations with different complexities under one- and two-source Penman–Monteith (PM) equations. The results showed that the mean absolute percent error (MAPE) for the LE estimates from the one- and two-source PM equations varied from 32% to 53%, and the uncertainties were caused mainly by the resistance parameterizations. Calibrating the parameters required in the resistance estimations could improve the performance of the PM equations; specifically, the MAPEs for the one-source PM equations were approximately 16%, whereas they were 38% for the two-source PM equations, emphasizing that multiple resistances result in increased uncertainties. The following conclusions were reached: 1) the empirical and biophysical parameters required in resistance estimations were responsible for the uncertainty; 2) increasingly complex resistance parameterizations resulted in greater uncertainties in LE estimates; and 3) models without resistance parameterizations exhibited reduced uncertainties in LE estimates.

Simulation Analysis of Penetration Performance of Tungsten Alloy and Tungsten Carbide Rod Penetrator

2012 ◽  
Vol 182-183 ◽  
pp. 283-287
Author(s):  
Qun Biao Wu ◽  
Pei Hui Shen ◽  
Rong Zhong Liu
Keyword(s):  
Tungsten Carbide ◽  
Simulation Analysis ◽  
Tungsten Alloy ◽  
Distinct Advantage ◽  
Penetration Mechanics ◽  
Armor Steel ◽  
The One ◽  
The Impact ◽  
Better Than ◽  
And Tungsten

In penetration mechanics, the material parameters of the rod penetrator are very important factors which influence the effect of penetration. The effect of each parameter changes with the impact velocity. Simulation analysis of two models filled with tungsten alloy and tungsten carbide separately penetrating semi-infinite armor steel target at medium to high velocities has been made to quantitatively analyze the key roles that the density and hardness play. Simulation results indicate that a dividing line of velocity exists between the penetrations of two materials. Above the line, tungsten alloy rod with greater density has a distinct advantage with increasing velocity. Below the line, the advantage of tungsten carbide rod with greater hardness is significantly more with the decreasing velocity. In the process of penetration, penetration velocity decreases rapidly from a high value to zero. The simulation result provides quantitative analytic basis which can be used to prove that the penetrator composed of two different materials is better than the one composed of homogenous material.

scholarly journals Retinomotor movements in the Antarctic fish Trematomus newnesi Boulenger submitted to different environmental light conditions

2007 ◽  
Vol 24 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Lucélia Donatti ◽  
Edith Fanta
Keyword(s):  
Pigment Epithelium ◽  
Antarctic Fish ◽  
Constant Darkness ◽  
Time Intervals ◽  
Mean Values ◽  
Environmental Light ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Antarctic

The Antarctic fish Trematomus newnesi (Boulenger, 1902) occurs from benthic to pelagic habitats, in seasonally and daily varied photic conditions that induce retinomotor movements. Fish were experimentally kept under constant darkness or light, and 12Light/12Dark for seven days. The retinomotor movement of the pigment epithelium was established through the pigment index, while that of the cones was calculated as the length of the myoid. The retinomotor movement of the pigment epithelium in T.newnesi,revealed that the adaptation to constant light occurred in the one hour of exposure, remaining constant for the next seven days. However, the adaptation to constant darkness, was slower. The difference between the mean values of the pigment indices in the time intervals of sampling was significant in the first hours of the experiment, and only after six hours they were not significant any more. The myoid of cones became elongated in darkness and contracted in light. In the experiments where T.newnesiwas exposed initially to 12 hours light followed by 12 hours darkness 12 was evidenced that the speed and intensity of the retinomotor movements was higher when darkness changed into light, than when light changed into darkness.

scholarly journals The influence of kihap on the impact of Dolio-chagui kicks in taekwondo

2014 ◽  
Vol 20 (1) ◽  
pp. 54-57
Author(s):  
Rodrigo Dias Martins ◽  
Debora Cantergi ◽  
Jefferson Fagundes Loss
Keyword(s):  
Martial Arts ◽  
Random Order ◽  
T Test ◽  
Real Effect ◽  
The Real ◽  
The Mean ◽  
The Difference ◽  
The Impact

The kihapis a technique used in several oriental martial arts. It is a yell used by practitioners with the ex pectation of enhancing the force of a hit. However, the real effect of using the kihapis unknown. Therefore, this study aims to compare the peak of acceleration of the Dolio-chaguikick in taekwondo performed with and without the use of kihap. Twenty two experienced taekwondo practitioners performed 30 kicks each against a punching bag, alternating in random order with and without kihap, while the acceleration of the punching bag was measured. A t-test was used to compare the difference between the mean acceleration in both conditions. Higher values were found with the use of kihap(7.8 ± 2.8 g) than without the use of kihap(7.1 ± 2.4 g), p< 0.01, r= 0.57. The results indicate that kihapenhances the impact of the kick.

scholarly journals INFLUENCE OF DIFFERENT VERSIONS ARTIFICIAL INSEMINATION OF GILTS OF THEIR TRAITS OF THE REPRODUCTIVE ABILITY CONSOLIDATION

2018 ◽  
Vol 56 ◽  
pp. 130-135
Author(s):  
M. V. Tserenyuk ◽  
O. M. Tserenyuk
Keyword(s):  
Artificial Insemination ◽  
Reproductive Capacity ◽  
Mean Square ◽  
Mean Square Deviation ◽  
Reproductive Ability ◽  
Coefficient Of Variability ◽  
Current Instruction ◽  
The Mean ◽  
The Difference ◽  
The Impact

In addition to assessing the absolute performance of animals, the impact of certain technological approaches, breeding influence and other external organized factors on the consolidation of pigs groups on certain grounds should be evaluated. Breeding consolidation is a desirable breeding process that is realized through more motivated consolidation of intra-breeding structural units for maintaining a significant level of intergroup differentiation and variability. If the issue relates to the rearing young animals that are introduced into the herd, this is the most urgent issue that needs to be monitored. The purpose of the research is to determine the consociality of the main signs of reproductive ability of the gilts, which are checked at different rates of artificial insemination of sows of the main herd. The research was carried out at the Shubs`ke farm in the Bogoduhivsky District of Kharkiv Oblast at the pig farm for the pure breeding of the Welsh breed pigs (breeding reproductive status from 2014). In order to evaluate the optimal multiplicity (from single to triple), a gilts with a total of 30 heads was selected. The main indicators of reproductive ability of gilts (multiplicity, weight of nest at birth and excommunication and keeping piglets before weaning on day 28) were evaluated. Recalculation on the weight of the litter at weaning at the weight of the nest at extermination in 60 days was carried out in accordance with the current instruction on the boning of pigs. The results of researches were worked out according to traditional methods by the method of variation statistics. Consolidation of individual indicators of reproductive capacity of gilts was calculated to the total number of evaluated animals. In the previous stage of the research, it was found that the use of multiple insemination of gilts compared to single insemination is positively reflected at the level of their reproductive ability. A decrease in the percentage of non-productive inseminants in animal groups has been established. Triple insemination of gilts allows for 1.14 piglets to be obtained more compared to single insemination of the same pigs (p < 0.01). Also, for three times insemination of gilts, in comparison with single insemination, larger nest for weaning were obtained (by 14.24 kg, converted to 60th day p < 0.01). At the same time, the reduction in the keeping of piglets to weaning for increase frequency of insemination of gilts. According to the multiplicity of gilts, the most consolidated level of symptoms per group was obtained for single insemination. Increasing the multiplicity of insemination negatively affected the consolidation of the multiplicity of the piglets (as for determining the coefficients of phenotypic consolidation due to the mean square deviation, so, and for determining the coefficient of variability). The least consolidated in terms of multiplicity were uterus for double insemination. It should also be noted that there is little difference, in general, on the indicators of the theonotypical consolidation of the multiplicity of piglets between different groups of animals. So this difference between the most contrasting groups was 0.447 points for determining the coefficients due to the mean square deviation and 0.397 points for the determination due to the coefficient of variability, respectively. By weight of the same litters at birth, the most consolidated group was gilts, which was inseminated twice. The least consolidated are trimmed three times, respectively. The difference as a whole, according to the indicators of the theonotype consolidation of the mass of the litter’s piglets at birth, between different groups of pigs was even smaller. The difference between the most contrasting groups was 0.270 points for determining the coefficients due to the mean square deviation and 0.260 points for the determination due to the coefficient of variability, respectively. On the basis of the mass of the litter at weaning, the most consolidated level of symptoms was obtained in the group of gilts for triple insemination. The least consolidated group, respectively, was gilts for single insemination. At the same time, on the basis of the weight of the litter at weaning, the slightest differences were obtained after the consolidation of the signs between different groups of pigs. The difference between the most contrasting groups was 0.173 points for determining the coefficients due to the mean square deviation and 0.248 points for the determination due to the coefficient of variation, respectively. At different rates of insemination of gilts, there are no significant differences between the groups between the groups in terms of the consolidation of signs of reproductive ability. Also, there was no clear effect on increasing the multiplicity of insemination of gilts to the consolidation of their signs of reproductive qualities.

Effects of Orthokeratology Lens On Axial Length Elongation in Myopia With Anisometropia Children

2021 ◽  
Author(s):  
Ziyang Chen ◽  
Kai-Ming Chen ◽  
Ying Shi ◽  
Zhao-Da Ye ◽  
Sheng Chen ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Axial Length ◽  
Statistical Significance ◽  
Spherical Equivalent ◽  
Significant Difference ◽  
The Mean ◽  
The Difference ◽  
Better Than ◽  
Group 1

Abstract AimTo investigate the effect of orthokeratology (OK) lens on axial length (AL) elongation in myopia with anisometropia children.MethodsThirty-seven unilateral myopia (group 1) and fifty-nine bilateral myopia with anisometropia children were involved in this 1-year retrospective study. And bilateral myopia with anisometropia children were divided into group 2A (diopter of the lower SER eye under − 2.00D) and group 2B(diopter of the lower SER eye is equal or greater than − 2.00D). The change in AL were observed.The datas were analysed using SPSS 21.0.Results(1) In group 1, the mean baseline AL of the H eyes and L eye were 24.70 ± 0.89 mm and 23.55 ± 0.69 mm, respectively. In group 2A, the mean baseline AL of the H eyes and L eyes were 24.61 ± 0.84 mm and 24.00 ± 0.70 mm respectively. In group 2B, the mean baseline AL of the H eyes and L eyes were 25.28 ± 0.72 mm and 24.70 ± 0.74 mm. After 1 year, the change in AL of the L eyes was faster than the H eyes in group 1 and group 2A (all P<0.001).While the AL of the H eyes and L eyes had the same increased rate in group 2B. (2) The effect of controlling AL elongation of H eyes is consistent in three groups (P = 0.559).The effect of controlling AL elongation of L eyes in group 2B was better than that in group 1 and group 2A (P < 0.001). And the difference between group 1 and group 2A has no statistical significance. (3) The AL difference in H eyes and L eyes decreased from baseline 1.16 ± 0.55mm to 0.88 ± 0.68mm after 1 year in group 1.And in group 2A, the AL difference in H eyes and L eyes decreased from baseline 0.61 ± 0.34mm to 0.48 ± 0.28mm. There was statistically significant difference (all P<0.001). In group 2B, the baseline AL difference in H eyes and L eyes has no significant difference from that after 1 year (P = 0.069).ConclusionsMonocular OK lens is effective on suppression AL growth of the myopic eyes and reduce anisometropia value in unilateral myopic children. Binocular OK lenses only reduce anisometropia with the diopter of the low eye under − 2.00D. Binocular OK lenses cannot reduce anisometropia with the diopter of the low eye equal or greater than − 2.00D. Whether OK lens can reduce refractive anisometropia value is related to the spherical equivalent refractive of low refractive eye in bilateral myopia with anisometropia children after 1-year follow-up.

scholarly journals Specialization and Performance: Evidence from NCAA 4 × 400 m Relay Times

Economies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 96
Author(s):  
Candon Johnson ◽  
Robert Schultz ◽  
Joshua C. Hall
Keyword(s):  
Performance Measure ◽  
Division I ◽  
Division Iii ◽  
Overall Performance ◽  
The Difference ◽  
And Performance ◽  
Using Data ◽  
The Impact ◽  
Better Than

This paper investigates the impact of having open 400 meter (400 m) runners on NCAA relay teams. Using data from 2012–2016 containing the top 100 4 × 400 m in each NCAA Division relay times for each year, it is found that more 400 m specialists lead to an increase in the overall performance of the team, measured by a decrease in relay times. The effect is examined across Division I–III NCAA track teams. The results are consistent across each division. We view this as a test of the role of specialization on performance. Using runners who specialize in 400 m races should increase overall team performance as long as specialization does not lead to an inefficient allocation of team human capital. An additional performance measure is used examining the difference between projected and actual relay times. Divisions I and II are found to perform better than projected with an increase in 400 m runners, but there is no effect found in Division III.

scholarly journals Persepsi Petani terhadap Pilihan Menjual Padi Kepada Penebas atau Perpadi (Kasus Subak Benel, Desa Kaliakah, Kecamatan Negara, Kabupaten Jembrana)

2017 ◽  
pp. 563
Author(s):  
I MADE PRASADA ARY WIRAWAN ◽  
I DEWA PUTU OKA SUARDI ◽  
I MADE SARJANA
Keyword(s):  
T Test ◽  
Mean Difference ◽  
P Value ◽  
Food Crops ◽  
Test Program ◽  
Qualitative Descriptive ◽  
The Mean ◽  
The Difference ◽  
The Government ◽  
Better Than

Farmers Perception Of Options To Sell Rice Penebas Or Perpadi(especially in Subak Benel, Kaliakah Village, Negara districts,Jembrana Regency) Various efforts have been implemented by the Provincial Food Crops Agency of Balito stabilize the price of grain, this is done by giving Funds of Rural EconomicEmpowerment Capital to the government for the purchase of rice. Although it hasbeen done from 2003, farmers are still selling it to Penebas with a bondage system.The purpose of this study to determine the perception of farmers to the choice ofselling rice to Perpadi or Penebas seen and differences in farmers' perceptions of thechoice of selling rice to Penebas or Perpadi. The research location is located in SubakBenel, Kaliakah Village, State District, Jembrana District. The analytical methodused is qualitative descriptive that aided with score, to answer the purpose ofresearch by using questionnaire. The results of this study indicate that the perceptionof farmers to the choice of selling rice to Perpadi better than to Penebas. This is seenin the achievement of the farmers' choice of selling paddy to Perpadi is very goodand to Penebas is good. The difference of Perpadi with Penebas is measured throughDifferent Test with SPSS Independent Sample T test program which the result of Sigvalue. Or p value of 0.004 where <0.05 then there is a statistically significantdifference in probability 0.05, the mean difference or mean of both groups is shownin Mean Difference ie .29559.

The Effect of Waking Suggestion on Post-Hypnotic Amnesia

1981 ◽  
Vol 11 (1) ◽  
pp. 44-46 ◽  
Author(s):  
D.P. Fourie
Keyword(s):  
Point Of View ◽  
The Other ◽  
Hypnotic Susceptibility ◽  
The Subject ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
The Relationship ◽  
Female Subjects

It is increasingly realized that hypnosis may be seen from an interpersonal point of view, meaning that it forms part of the relationship between the hypnotist and the subject. From this premise it follows that what goes on in the relationship prior to hypnosis probably has an influence on the hypnosis. Certain of these prior occurences can then be seen as waking suggestionns (however implicitly given) that the subject should behave in a certain way with regard to the subsequent hypnosis. A study was conducted to test the hypothesis that waking suggestions regarding post-hypnotic amnesia are effective. Eighteen female subjects were randomly divided into two groups. The groups listened to a tape-recorded talk on hypnosis in which for the one group amnesia for the subsequent hypnotic experience and for the other group no such amnesia was suggested. Thereafter the Stanford Hypnotic Susceptibility Scale was administered to all subjects. Only the interrogation part of the amnesia item of the scale was administered. The subjects to whom post-hypnotic amnesia was suggested tended to score lower on the amnesia item than the other subjects, as was expected, but the difference between the mean amnesia scores of the two groups was not significant.

scholarly journals III. On the uneliminated instrumental error in the observations of magnetic dip

1869 ◽  
Vol 17 ◽  
pp. 427-429
Keyword(s):  
Mean Value ◽  
Usual Method ◽  
Centre Of Gravity ◽  
Single Reading ◽  
The Mean ◽  
The Difference ◽  
The One ◽  
Number Of Passes ◽  
Source Of Error ◽  
Complete Observation

A single reading of one end of a dipping-needle placed in a dip-circle provided with microscopes for observing is liable to a variety of instrumental errors, which are eliminated by taking the mean of the sixteen readings of the two ends in the eight different positions included in a complete observation. Nevertheless it is found that with the best modern instruments a mean value results from these sixteen observations different for each different needle, and that the difference between the results obtained with two different needles is not the same at all times. The irregularities in the values of the dip observed at Bombay with two needles of excellent character made by Barrow of London, led the author to investigate the effect of a hypothetical irregularity in the shape of the axle of the needle, such that a section of the axle by a plane perpendicular to its axis would be elliptical instead of circular in form. Another source of error, which was brought to the notice of the Royal Society many years ago in a paper published in the Proceedings, is the displacement of the centre of gravity of the needle from the centre of the axle, combined with inequality in the magnetization of the needle when the poles are direct and reversed. Experience has led the author to the conclusion that the usual method of magnetization, by a definite number of passes of the same pair of bar-magnets, communicates magnetism to the needle very unequally when the one end of the needle is made north and when the other end is made north. Consequently it is advisable to investigate the effects of ellipticity of the axle and of displacement of the centre of gravity at the same time, which the author proceeds to do.

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