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排序方式: 共有152条查询结果,搜索用时 15 毫秒
1.
《Journal of dairy science》2022,105(12):9623-9638
A simulation study was conducted to examine accuracy of estimating daily O2 consumption, CO2 and CH4 emissions, and heat production (HP) using a spot sampling technique and to determine optimal spot sampling frequency (FQ). Data were obtained from 3 experiments where daily O2 consumption, emissions of CO2 and CH4, and HP were measured using indirect calorimetry (respiration chamber or headbox system). Experiment 1 used 8 beef heifers (ad libitum feeding; gaseous exchanges measured every 30 min over 3 d in respiration chambers); Experiment 2 used 56 lactating Holstein-Friesian cows (restricted feeding; gaseous exchanges measured every 12 min over 3 d in respiration chambers); Experiment 3 used 12 lactating Jersey cows (ad libitum feeding; gaseous exchanges measured every hour for 1 d using headbox style chambers). Within experiment, averages of all measurements (FQALL) and averages of measurements selected at time points with 12, 8, 6, or 4 spot sampling FQ (i.e., sampling every 2, 3, 4, and 6 h in a 24-h cycle, respectively; FQ12, FQ8, FQ6, and FQ4, respectively) were compared. Within study a mixed model was used to compare gaseous exchanges and HP among FQALL, FQ12, FQ8, FQ6, and FQ4, and an interaction of dietary treatment by FQ was examined. A regression model was used to evaluate accuracy of spot sampling within study [i.e., FQALL (observed) vs. FQ12, FQ8, FQ6, or FQ4 (estimated)]. No interaction of diet by FQ was observed for any variables except for CH4 production in experiment 1. No FQ effect was observed for gaseous exchanges and HP except in experiment 2 where CO2 production was less (5,411 vs. 5,563 L/d) for FQ4 compared with FQALL, FQ12, and FQ8. A regression analysis between FQALL and each FQ within study showed that slopes and intercepts became farther from 1 and 0, respectively, for almost all variables as FQ decreased. Most variables for FQ12 and FQ8 had root mean square prediction error (RMSPE) less than 10% of the mean and concordance correlation coefficient (CCC) greater than 0.80, and RMSPE increased and CCC decreased as FQ decreased. When a regression analysis was conducted with combined data from the 3 experiments (mixed model with study as a random effect), results agreed with those from the analysis for the individual studies. Prediction errors increased and CCC decreased as FQ decreased. Generally, all the estimates from FQ12, FQ8, FQ6, and FQ4 had RMSPE less than 10% of the means and CCC greater than 0.90 except for FQ6 and FQ4 for O2 consumption and CH4 production. In conclusion, the spot sampling simulation with 3 indirect calorimetry experiments indicated that FQ of at least 8 samples (every 3 h in a 24-h cycle) was required to estimate daily O2 consumption, CO2 and CH4 production, and HP and to detect changes in those in response to dietary treatments. This sampling FQ may be considered when using techniques that measure spot gas exchanges such as the GreenFeed and face mask systems. 相似文献
2.
有近20年历史的爱立信AXE10交换机在信息时代到来之际再放异彩,目前,它作为公共平台广泛应用于PSTN、ISDN、IN,PLMN、信令网和商务通信等。 相似文献
3.
Poly(vinylbenzyltrimethylammonium chloride)‐graft‐cotton cellulose, an anion‐exchange matrix, was synthesized by a mutual radiation‐induced grafting technique with a 60Co γ‐radiation source. The grafted matrix was characterized by grafting yield estimation, elemental analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The grafting yield decreased with the increase in the dose rate. However, the grafting yield and nitrogen content of grafted samples increased almost linearly with an increase in the total irradiation dose. To evaluate the performance of the grafted anion‐exchange matrix, the protein adsorption and elution behavior were investigated in a continuous column process under various experimental conditions, with bovine serum albumin used as a model protein. The binding and elution behavior of the anion‐exchange matrix depended on different experimental parameters, such as the grafting yield, ionic strength, pH of the medium, and amount of protein loaded. From a breakthrough curve, the equilibrium binding capacity and elution percentage of the grafted anion‐exchange matrix were estimated to be 40 mg/g and 94%, respectively. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5512–5521, 2006 相似文献
4.
Todd Michael; Armeli Stephen; Tennen Howard; Carney Margaret Anne; Affleck Glenn 《Canadian Metallurgical Quarterly》2003,17(4):303
Data from 2 daily diary studies of stress, negative affect, and drinking were used to examine the correspondence between global self-reports of drinking to cope (DTC) and within-person stress/negative affect-drinking associations. In Study 1, 83 community-residing drinkers recorded data in nightly booklets on negative events, perceived stress, negative affect, and drinking for 60 consecutive days. In Study 2, 88 community-residing drinkers recorded data on negative events and negative interpersonal exchanges nightly and negative affect and drinking in near-real time on palmtop computers for 30 consecutive days. Both studies showed only modest correspondence between self-reported DTC and between-person differences in within-day, daily, and weekly associations between stress/negative affect and drinking. The findings indicate that individuals who report higher DTC simply may drink across a wider variety of conditions than those who report relatively lower DTC. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
李太 《湖北工业大学学报》2014,(3):8-12
在34个团队共688份问卷的基础上,从资源为导向的发展观出发,探讨领导-部属交换水平对员工职业成长的影响机制,并检验了领导-部属交换差异性在上述资源分配影响过程中的调节作用。通过跨层次的研究方法,研究发现领导-部属交换水平对员工职业成长有正向相关作用,并且对员工的迎合行为有正向影响,员工迎合行为在上述影响过程中起到中介作用。在探讨领导-部属交换差异性对上述影响机制的调节作用时,通过数据发现,领导-部属交换差异性在领导-部属交换水平对员工职业成长的影响中有调节作用。阐述了上述研究结论所产生的原因,探讨了领导-部属交换过程领导所面临的双重困境。 相似文献
6.
《Journal of the European Ceramic Society》2019,39(1):59-65
The performances of mixed ionic and electronic conductors is used in many applications, such as oxygen transport membranes or electrodes in solid oxide fuel cells. The performances of these systems depend mainly on two fundamental parameters including oxygen diffusion (DO) and the oxygen exchange coefficient (k). This work focuses on the impact of the oxygen partial pressure on oxygen diffusion and surface exchange coefficients of mixed conducting materials, as reported studies are scarce in the literature. In this way, two different mixed conducting materials are studied, namely, La0.6Sr0.4Fe0.6Ga0.4O3-δ, a perovskite-type material, and the nickelate La2NiO4+δ. The DO and k coefficients are determined by a specific oxygen permeation measurement and by the isotopic exchange depth profile method. 相似文献
7.
文章以唐代中日佛教干漆造像交流为研究对象,以鉴真东渡为切入点,通过历史文献等资料整理,从历史学和社会学,艺术学,设计学的角度对鉴真东渡的历史背景、鉴真六次东渡及东渡后对日本佛教干漆造像的影响三个方面进行分析和阐述,结合日本奈良时代特定的历史环境和背景,探究唐代中日佛教干漆造像交流脉络,揭示鉴真东渡及其团队对日本佛教干漆造像的深远影响,为唐代中日佛教干漆造像交流研究提供新的研究思路。 相似文献
8.
9.
Tangirala Subrahmaniam; Green Stephen G.; Ramanujam Rangaraj 《Canadian Metallurgical Quarterly》2007,92(2):309
Dyadic relationships in an organizational hierarchy are often nested within one another. For instance, the relationship between a supervisor and an employee is nested within the relationship between that supervisor and his or her boss. In that context, the authors propose that the supervisor's relationship with his or her boss (leader-leader exchange) moderates the effects of the supervisor's relationship with the employee (leader-member exchange). Specifically, the authors argue that leader-member exchange has a stronger positive effect on employees' attitudes toward the organization and its customers when leader-leader exchange is higher. Cross-level analysis of data from 581 frontline nurses and 29 supervisors in a midwestern hospital supports this contention. Implications for research and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
The study of leadership exchanges is extended by studying both leader-member exchanges (LMXs) and, coworker exchanges (CWXs). Data from 110 coworker dyads were used to examine relationships between LMXs and CWXs and between exchange relationships and work attitudes. As predicted, the interaction between 2 coworkers' LMX scores predicted CWX quality for the coworker dyad. Also, after controlling for LMX, greater diversity in a worker's CWX relationships was negatively related to his or her organizational commitment but not job satisfaction. The quality of a worker's CWX relationships, however, did not moderate the relationship between CWX diversity and work attitudes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献