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61.
Holstein heifer calves from selected and control lines were treated with growth hormone-releasing factor to determine whether the magnitude of the pituitary growth hormone response is associated with genetic potential for milk yield. Cows in the selected line were bred to highest Predicted Difference milk sires available each year, while control line cows were bred to bulls that were average for 1964 milk production. Eight calves from each line of similar age (206 to 210 days) and weight (205 kg average) were injected intravenously with .1 microgram/kg growth hormone-releasing factor. Dams' first lactation 305-day mature equivalent records were 10,192 +/- 495 kg for selected calves and 6,908 +/- 376 kg for control calves. Before treatment, GH tended to be higher in selected than control calves (mean +/- SE: selected = 7.5 +/- 1.8, control = 4.6 +/- .4 ng/ml). After injection, peak GH were reached within 20 min and were similar in selected and control calves, averaging 66 +/- 16 and 73 +/- 13 ng/ml, respectively. Results indicate that the magnitude of the growth hormone response to growth hormone-releasing factor is not related to future performance of dairy calves. 相似文献
62.
A compact dipole antenna for the terrestrial digital multimedia broadcasting (TDMB) application is presented. The length of the antenna is about 0.06λ at the TDMB resonance frequency of 190 MHz. Miniaturization of the antenna is achieved by using meander structures and lumped elements. The proposed antenna has two resonance frequencies and covers the TDMB band from 174 MHz to 216 MHz in Korea. The antenna has good impedance bandwidth and radiation characteristics for the TDMB. The experimental results of the designed dipole antenna are presented and analyzed. 相似文献
63.
Onishi K. Rino Choi Chang Seok Kang Hag-Ju Cho Young Hee Kim Nieh R.E. Jeong Han Krishnan S.A. Akbar M.S. Lee J.C. 《Electron Devices, IEEE Transactions on》2003,50(6):1517-1524
Bias-temperature instabilities (BTI) of HfO/sub 2/ metal oxide semiconductor field effect transistors (MOSFETs) have been systematically studied for the first time. NMOS positive BTI (PBTI) exhibited a more significant V/sub t/ instability than that of PMOS negative BTI (NBTI), and limited the lifetime of HfO/sub 2/ MOSFETs. Although high-temperature forming gas annealing (HT-FGA) improved the interface quality by passivating the interfacial states with hydrogen, BTI behaviors were not strongly affected by the technique. Charge pumping measurements were extensively used to investigate the nature of the BTI degradation, and it was found that V/sub t/ degradation of NMOS PBTI was primarily caused by charge trapping in bulk HfO/sub 2/ rather than interfacial degradation. Deuterium (D/sub 2/) annealing was found to be an excellent technique to improve BTI immunity as well as to enhance the mobility of HfO/sub 2/ MOSFETs. 相似文献
64.
Advances in internet congestion control 总被引:1,自引:0,他引:1
Ryu Seungwan Rump Christopher Qiao Chunming 《Communications Surveys & Tutorials, IEEE》2003,5(1):28-39
In this survey, we first review the concept of congestion control with a focus on the Transmission Control Protocol⁄Internet Protocol (TCP⁄IP). We describe many recently proposed algorithms to combat congestion and improve performance, particularly active queue management (AQM) algorithms such as random early detection (RED) and its variants. We then survey control-theoretic analysis and design of TCP congestion control with an AQM scheme. In addition, we discuss three problems associated with AQM proposals: parameter setting, the insensitivity to the input traffic load variation, and the mismatch between macroscopic and microscopic behavior of queue length dynamics. As alternatives to AQM algorithms, we also survey architectural approaches such as modification of source or network algorithms, and economic approaches including pricing or optimization of allocated resources. Finally, we list many open issues that persist in the design, operation, and control of the Internet. 相似文献
65.
We propose an efficient scheme for camera motion characterization in MPEG‐compressed video. The proposed scheme detects six types of basic camera motions through threshold‐based qualitative interpretation, in which fixed thresholds are applied to motion model parameters estimated from MPEG motion vectors (MVs). The efficiency and robustness of the scheme are validated by the experiment with real compressed video sequences. 相似文献
66.
Si-Woong Lee Jae Gark Choi Byoung-Ju Yun 《Electronics letters》2003,39(9):712-714
An adaptive contour smoothing algorithm designed as a preprocessor for shape coders is presented. In the method, the degree of the adaptive smoothing is controlled based on the significance of each contour point, which is quantified according to inter-region contrast in an intensity image. The actual smoothing consists of an expansion operator and a thinning algorithm. 相似文献
67.
R Albrecht TC Awes C Baktash P Beckmann F Berger R Bock G Claesson G Clewing L Dragon A Eklund RL Ferguson A Franz S Garpman R Glasow HA Gustafsson HH Gutbrod J Idh P Jacobs K Kampert BW Kolb P Kristiansson IY Lee H Loehner I Lund FE Obenshain A Oskarsson I Otterlund T Peitzmann S Persson F Plasil AM Poskanzer M Purschke H Ritter S Saini R Santo HR Schmidt T Siemiarczuk SP Sorensen E Stenlund ML Tincknell GR Young 《Canadian Metallurgical Quarterly》1991,44(6):2736-2752
68.
AB Young 《Canadian Metallurgical Quarterly》1997,153(8-9):496-498
The gene for Huntington's disease is widely expressed in brain and yet the illness is characterized pathologically by a distinct regional pattern of cell death. Various theories for this selective vulnerability have been offered but the most compelling remains that of abnormal energy metabolism. These issues are reviewed. 相似文献
69.
Hansen P.B. Raybon G. Koren U. Miller B.J. Young M.G. Newkirk M.A. Chien M.-D. Tell B. Burrus C.A. 《Electronics letters》1993,29(9):739-741
A 2 cm long three-contact multisection laser has been fabricated for modelocking at very low repetition rates. Active modelocking yields 8.0-12.3 ps pulses at 2.2, 4.3 and 6.5 GHz corresponding to the fundamental, first, and second harmonics of the cavity resonance frequency. This device demonstrates the feasibility of fabricating monolithic pulse sources operating at rates as low as the OC-48 Sonet transmission rate (2.488 Gbit/s).<> 相似文献
70.