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31.
To study the effect of time and different forms of hyperketonemia, with or without puerperal metritis, on insulin and glucose responses, 31 Holstein cows were subjected to glucose (GTT) and insulin tolerance tests (ITT) between 18 and 22 d before, and on days 7 and 60-70 after calving. Plasma concentrations of beta-hydroxybutyrate (BHB), nonesterified fatty acids, glucose, insulin, insulin-like growth factor I and leptin were measured from 18 d before until 70 d after calving. The revised quick insulin sensitivity index (RQUICKI) was calculated at each time point. First postpartum (PP) ovulation was monitored by milk progesterone. Based on BHB patterns and clinical findings, animals were classified as 1) Normoketonemic (NK, n = 9); 2) Transiently hyperketonemic (tHK, n = 7); 3) Continuously HK (cHK, n = 7); and 4) Continuously HK, with signs of puerperal metritis (cHK + PM, n = 6). Insulin area under the curve (AUC) and insulin response to glucose were significantly lower in the early PP period than in late-pregnancy (P < 0.001), and on day 7 after calving in cHK and cHK + PM groups compared to NK and tHK groups (P < 0.001). On day 7, insulin stimulated a decrease in plasma glucose in cHK, cHK + PMthan NK, and tHK groups. Normoketonemic cows (group 1) ovulated earlier than all other groups (P = 0.002). There was no correlation between GTT and ITT variables and the RQUICKI. Time had a significant effect on RQUICKI. Long-term hyperketonemia, especially combined with puerperal metritis, interacts with secretion of insulin and whole-body IR, and results in a significant delay in PP ovarian activity in dairy cows.  相似文献   
32.
Although hormonal changes during different phases of the oestrous cycle of bitches are well-described, knowledge about the luteal phase and anoestrus is incomplete. Furthermore, which paracrine and autocrine critical factors that differentiate between follicles destined for atresia and those that continue to develop are unknown. In this study, ovarian tissue was collected from 39 healthy bitches that were subject to ovariectomy or ovariohysterectomy for surgical neutering or medical purposes such as unwanted pregnancy. Bitches were allocated to different groups depending on the stage of the oestrous cycle. Serum progesterone, LH, FSH and 17β-estradiol (E2) -levels were determined and immunhistochemistry was performed for a variety of receptor antigens; Ki-67, vimentin, pan cytokeratin antibody, p53 and oestrogen receptor (ER) α antigens. Marked differences were found in progesterone concentration between pregnant and non-pregnant animals. Oestrogen concentration was significantly lower in pro-oestrus and ovulation than during the luteal phase. Although progesterone could be detected in cytoplasm of ovarian cells at each stage, its presence was restricted to follicular cells during anoestrus. A strong presence of AE1/AE3, vimentin and p53 was found in each oestrous stage, in contrast with Ki67. The localization of ERα appeared to vary during the oestrous cycle, a phenomenon that suggests a switch between target cells of oestrogen; while as a proliferation marker, the mild reaction of p53 during parturition suggests an apoptotic process at this stage of the cycle.  相似文献   
33.
The total concentration of all mercuryspecies in water, [THg]w, is a key water qualitymeasure. This paper proposes an analytical framework forthe analysis, interpretation and eventual projection ofstream (and river) [THg]w. Mercury (Hg) isconceptualized as being distributed among four carriergroups in water: suspended mineral particles, particulateorganic carbon, dissolved organic carbon, and inorganiccomplexes and ions. The conceptual understanding is used asa statistical analytical framework and turned into aquantitative model for Minnesota and Wisconsin based on some1000 data cases from 18 streams (watershed area: 9 ha–115500km2). The resultant model yields a coefficient ofdetermination of 92% for [THg]w of the fitting datasubset, or 94% for the evaluation subset. Its coefficientshave well defined physical meanings, and are generallyconsistent with independent field measurements from the sameregion or elsewhere. The model provides a comprehensive andquantitative view of the Hg contents of the carriers: thecontents increase with the proportion of watershed area aswetlands or as forests, rise drastically and then fallprecipitously during spring snowmelt, and otherwise peak inthe growing season and reach a minimum in the presence ofsnowpack. The model further reveals that dissolved Hg tendsto increase with emission-related wet sulfate depositionacross the data region.  相似文献   
34.
Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.  相似文献   
35.
To study the possible effects of different inclusion levels of distillers dried grain with solubles (DDGS) on the lipid peroxidation and glutathione redox status of chickens, 200 three-week-old Ross 308 cockerels were assigned to four treatment groups of 50 birds each. The groups were fed a control and three experimental, isocaloric and isonitrogenous grower diets containing 15, 20 and 25% DDGS, respectively, combined with lysine (Lys) and methionine (Met) supplementation until 6 weeks of age. It was found that DDGS inclusion increased the ether extract content of the diets which resulted in higher reduced glutathione (GSH) content and elevated glutathione peroxidase activity (GSHPx) in the liver. However, DDGS addition with Lys and Met supplementation did not influence the malondialdehyde content of the blood and the liver. The oleic acid proportion of the diet showed a close positive correlation with GSH content of the liver. A smaller ratio of methionine and cysteine in the diet with DDGS resulted in significantly higher liver GSH content. GSHPx activity increased parallel with the elevated GSH content of the liver homogenate, suggesting that the enzyme is activated by the actual supply of its co-substrate. In conclusion, the results show that DDGS, even at a high inclusion level combined with Lys and Met supplementation, has no initiative effect on lipid peroxidation in the blood and liver of broiler chickens.  相似文献   
36.
The effects of abiotic and biotic drivers on soil respiration (Rs) were studied in four grassland and one forest sites in Hungary in field measurement campaigns (duration of studies by sites 2-7 years) between 2000 and 2008. The sites are within a 100 km distance of each other, with nearly the same climate, but with different soils and vegetation. Soil respiration model with soil temperature (Ts) and soil water content (SWC) as independent variables explained larger part of variance (range 0.47-0.81) than the Lloyd and Taylor model (explained variance: 0.31-0.76). Direct effect of SWC on Rs at much smaller temporal and spatial scale (1.5 h, and a few meters, respectively) was verified.Soil water content optimal for Rs (SWCopt) was shown to significantly (positively) depend on soil clay content, while parameter related to activation energy (E0) was significantly (negatively) correlated to the total organic carbon content (TOC) in the upper 10 cm soil layer. Dependence of model parameters on soil properties could easily be utilized in models of soil respiration. The effect of current (a few hours earlier) assimilation rates on soil respiration after removing the effect of abiotic covariates (i.e. temperature and water supply) is shown. The correlation maximum between the Rs residuals (Rs_res, from the Rs (SWC, Ts) model) and net ecosystem exchange (NEE) was found at 13.5 h time lag at the sandy grassland. Incorporating the time-lagged effect of NEE on Rs into the model of soil respiration improved the agreement between the simulated vs. measured Rs data. Use of SWCopt and E0 parameters and consideration of current assimilation in soil respiration models are proposed.  相似文献   
37.

Purpose

The Oh?e River has received contamination from metal mining and metallurgy (mainly Cu, Pb, Sn, U, Zn) over the previous five centuries. This contamination history has been poorly documented. Contamination has entered the river system in its middle reach, where the channel is incised and bedrock confined, which impedes overbank deposition. Our objective was to locate and describe a sedimentary record in this unfavourable depositional setting.

Materials and methods

Three former channel bars that have coalesced with the riverbank were revealed by examination of historical and current maps and a digital terrain model. Manual coring in the bar and in situ (handheld) X-ray fluorescence (XRF) spectroscopy provided data for developing a contamination chemostratigraphy, which was correlated with the mining history in the region. Detailed topographic examination of the bar and valley edge was important to understanding the evolution of one of the bars. Optically stimulated luminescence (OSL) dating was used to verify the timing of deposition.

Results and discussion

Handheld XRF for in situ analysis of element composition is efficient for studying contaminated sediment bodies with complex stratigraphy, which require extensive coring and stratigraphic correlation. Despite the unfavourable settings, the channel bars trapped sufficient sediment to produce a record that correlates with the history of contamination in the drainage basin. In the bar studied in greatest detail, we observed a surprising amount of contamination passing through the Oh?e River channel (up to 300 mg kg?1 of Cu, 340 mg kg?1 of Pb and 630 mg kg?1 of Sn in fine sand and silt deposits) associated with a pollution climax in the sixteenth and seventeenth centuries. Modern contamination (Hg and U deposited in the nineteenth and twentieth centuries) was entrapped with low efficiency based on comparable concentrations of Hg and U located 90 km downstream.

Conclusions

The efficacy of the use of historical maps and detailed fieldwork was demonstrated by identification of unique depositional meso-environments, which are rare in bedrock-confined fluvial systems. The contamination chemostratigraphy of the bar deposits was correlated with the local mining and pollution history and contributed to an understanding of the bar evolution. The approach used in our study may be applicable to other montane rivers with historic ore mining and processing in their basins.
  相似文献   
38.
In cats, accuracy of parturition day prediction by ultrasonographic measurement of foetal structures is decreasing towards the end of gestation. Foetal measurements during the last days of pregnancy are scarce. We determined foetal biparietal, abdominal and eye diameter (BPD, AD and ED, respectively) by ultrasonography as well as maternal blood progesterone (P4) within five days of delivery to predict parturition date and calculate accuracy of prediction. Foetal BPD at birth was compared with newborn kitten head diameter (HD). Kitten HD, crown‐rump length (CRL) and body weight were compared by breed and gender. Ultrasonography measurements were carried out on the day of parturition in 14 queens, and on days 62–63 after the first mating and repeated 24–72 hr later in ten other cats. Accuracy of parturition day prediction using BPD and AD was determined based on the equations of Beccaglia et al. (2008) Veterinary Research Communications, 32(Suppl 1), S99 and Garcia Mitacek et al. (2015) Theriogenology, 84, 1131. Progesterone was measured at the time of presentation and repeated 24–72 hr later if parturition did not occur. Data were analysed with linear regression, t test, Mann–Whitney U test, one‐way anova and Kruskal–Wallis test. There was a moderate relationship between BPD, days before birth (DBB) and litter size. AD and DBB had a low agreement, and ED was not associated with DBB. BPD at birth was significantly related to HD. The accuracy of parturition day prediction using BPD and AD was 27–53% and 17–35%, respectively. Kitten HD was associated with body weight, and both were inversely related to litter size. Newborn biometric measurements differed by breed but not by gender. Progesterone decreased towards parturition and reached 3.18 ± 1.68 ng/ml on the day of delivery. In conclusion, close to birth, the combination of foetal ultrasonography and maternal blood P4 rather than each as a sole predictor of parturition is recommended.  相似文献   
39.
Two experiments were performed to evaluate the normal development of the rabbit heart. In the first experiment the most intensive period of heart development was determined in rabbit embryos. The second experiment studied the most intensive period of heart development, determined in the first experiment, by concentrated sampling at 8-hour intervals. After cutting open the uterine wall opposite the discoid placenta, rabbit embryos were removed from the ampullae of the uterus using capillary tubes, under stereomicroscope at fivefold magnification. The embryos were subsequently placed into 4% formalin solution for 24 h. After fixation, slides stained with haematoxylin and eosin were made for histological examination. In the first experiment 51 embryos were examined, while during the second experiment a total of 113 embryos, representing different stages of development, were collected. Finally the data obtained on rabbits were compared with the well-known development of the heart in humans and mice.  相似文献   
40.
The expanding field of Veterinary Public Health places new demands on the knowledge and skills of veterinarians. Veterinary curricula must therefore adapt to this new profile. Through the introduction of case studies dealing with up-to-date issues, students are being trained to solve (real-life) problems and come up with realistic solutions. At the Department of Public Health and Food Safety of the Veterinary Faculty at the University of Utrecht in the Netherlands, positive experiences have resulted from the new opportunities offered by the use of information and communication technology (ICT) in education. The possibility of creating a virtual classroom on the Internet through the use of WebCT software has enabled teachers and students to tackle emerging issues by working together with students in other countries and across disciplines. This article presents some of these experiences, through which international exchange of ideas and realities were stimulated, in addition to consolidating relations between universities in different countries. Long-distance education methodologies provide an important tool to achieve the increasing need for international cooperation in Veterinary Public Health curricula.  相似文献   
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