Effects of administration of bovine somatotropin on milk yield and composition

Thirty-two Holstein cows were assigned to four treatment groups in a continuous lactation trial to evaluate effects of daily subcutaneous injections of 0 (A), 5.15 (B), 10.3 (C), and 20.6 mg (D) of recombinantly derived bovine somatotropin monomer. Responses were milk yield and composition, component yields, net energy intake, body weight, and somatic cell counts. Treatments began in fall, 28 to 35 d postpartum, and continued for 266 d. Base ration was corn silage and concentrate. Least squares means of milk and constituent yields and gross efficiency of milk production differed among treatments, but percentage fat and protein, energy intake, body weights, and somatic cell counts did not. Least squares means of 3.5% FCM were 21.3 (A), 25.0 (B), 26.2 (C), and 28.5 kg/d (D); fat and protein yields showed similar response to treatment. Milk yields adjusted for pretreatment yields were 21.1 (A), 25.5 (B), 26.5 (C), and 29.3 kg/d (D). Orthogonal contrasts showed lower milk and constituent yields and net energy intake for control (A) than for hormone-injected cows (B, C, D), but no differences were detected between treatments B, C, and D. Gross efficiency of production (3.5% FCM/feed net energy intake) was greater for hormone-injected cows.     

Evaluation of heat transfer correlations for HCCI engine modeling

Combustion in HCCI engines is a controlled auto-ignition of well-mixed fuel, air and residual gas. The thermal conditions of the combustion chamber are governed by chemical kinetics strongly coupled with heat transfer from the hot gas to the walls. The heat losses have a critical effect on HCCI ignition timing and burning rate, so it is essential to understand heat transfer process in the combustion chamber in the modeling of HCCI engines. In the present paper, a comparative analysis is performed to investigate the performance of well-known heat transfer correlations in an HCCI engine. The results from the existing correlations are compared with the experimental results obtained in a single-cylinder engine. Significant differences are observed between the heat transfer results obtained by using Woschni, Assanis and Hohenberg correlations.     

Supplementing Holstein cows with low doses of bovine somatotropin prepartum and postpartum reduces calving-related diseases

The objective of this study was to evaluate whether supplementing Holstein cows with bovine somatotropin (bST; 142.8 mg/14 d), beginning at 21 d (±3 d) before expected calving and continuing through 42 d in milk (±3 d), affected the incidence rates of retained fetal membranes (RFM), metritis (MET), clinical mastitis (MAS), digestive problems (DIG), ketosis (KET), milk fever (MF), displaced abomasum (DA, left or right), lameness (LAM), or number of sick cows during the first 60 d in milk. Data for multiparous Holstein cows from 3 separate trials were merged for analyses (n = 437). Cows in the bST-supplemented group (n = 162) received biweekly subcutaneous injections of Posilac, whereas control cows (n = 166) and a group of cohorts (n = 109) were not supplemented. Incidences of disease were collected from the herd health records. Across all treatment groups, the incidence rates (number of diseased cows divided by the total number of cows) for RFM, MET, MAS, DIG, KET, MF, DA, and LAM were 8.47, 18.31, 16.02, 4.35, 4.35, 3.66, 3.20, and 3.66%, respectively. The incidence rates of RFM, MET, MAS, DIG, KET, MF, DA, and LAM for cows in the bST-supplemented, control, and cohort groups were 6.79, 7.83, and 11.93%; 16.05, 7.47, and 22.94%; 10.49, 18.07, and 21.10%; 1.23, 5.42, and 7.34%; 1.23, 6.02, and 6.42%; 2.47, 4.22, and 4.59%; 2.47, 3.61, and 3.67%; and 3.70, 3.61, and 3.67%, respectively. The percentages of sick cows (number of cows having one or more cases of disease divided by the total number of cows) in the bST-supplemented, control, and cohort groups were 33.95, 43.37, and 49.54%, respectively. Significant chi-squared values were detected between the bST-supplemented and control groups for MAS, DIG, and KET, with a greater number of healthy cows in the bST-supplemented group. No differences in incidences of diseases or sick cows were detected between the control and cohort groups. Results indicated that a low dose of bST supplemented to Holstein cows for 3 wk prepartum through 60 d in milk reduced the incidences of some calving-related diseases compared with nonsupplemented controls or cohorts. Importantly, no negative effects of bST supplementation on postpartum calving diseases were detected compared with nonsupplemented cows.     

Processed dietary plants demonstrate broad capacity for angiotensin converting enzyme and angiotensin II receptor binding inhibition in vitro

While the consumption of fruit and vegetables is protective against cardiovascular disease, the relative efficacy of specific plants is poorly substantiated. In addition, although most plants are consumed in a ‘processed’ state (i.e., including cooking), the bioactivity of processed forms of plants is also generally unknown. Effects on elements of the renin-angiotensin system (RAS) were studied in a selection of 131 dietary plant species, fungi or varietals, across 44 families, after standardised processing. Products were tested for in vitro inhibition of angiotensin converting enzyme (ACE) and of angiotensin II (AngII) binding to its receptor (AT₁R). The results indicated that ACE inhibition activity was weakly correlated with AngII to AT₁R inhibition and that ACE inhibitory activity was positively correlated with total polyphenolic content. These results highlight that processed forms of dietary plants exhibit broad capacity for in vitro modulation of RAS. Furthermore, considering the extensive ACE inhibitory activity reported for peptides derived from many dietary proteins, this implicates broad potential for RAS regulation by several dietary factors. With RAS elements also known to function in the gastro-intestinal (GI) tract, there is a need to understand the physiological role of dietary factors on GI function, blood pressure regulation and salt excretion.     

减少离散大系统两级镇定控制的保守性

The aim of this paper is to propose a new algorithm for multilevel stabilization of large scale systems. In two-level stabilization method, a set of local stabilizers for the individual subsystems in a completely decentralized environment is designed. The solution of the control problem involves designing of a global controller on a higher hierarchical level that provides corrective signals to account for interconnections effect. The principle feature of this paper is to reduce conservativeness in global controller design. Here, the key point is to reduce the effect of interactions instead of neutralizing them. In fact, unlike prior methods, our idea does not ignore the possible beneficial aspects of the interactions and does not try to neutralize them.     

地下商场的通风与空调设计

地下空间的内部环境优劣是影响人们身心健康的重要指标。作者通过地下商场通风空调施工实践,提出控制地下内部环境与节能所采取的措施,并谈几点粗浅看法,以供设计与运行管理参考。