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排序方式: 共有192条查询结果,搜索用时 31 毫秒
1.
1. Variations in the concentration of plasma cholesterol available to the developing oocyte over a three week period in Gallus domesticus are described.
2. There are small changes in concentration between weeks for individual birds, but no changes between consecutive days within weeks or times within days.
3. It is recommended that future attempts to assess the relationship between variation in blood and yolk cholesterol concentrations estimate blood cholesterol concentration from two samples taken a week apart. 相似文献
2.
The copper status of dairy herds in the Waikato, Taranaki and Northland regions between 1 August and 30 September was assessed by copper determinations made on composite sera from ten cows in each herd. Comparisons were made between two major groups categorised as as received and supplemented. In the latter, the cows received 2.0-6.0 g/day of copper sulphate orally from late gestation to the end of lactation. Mean copper values were determined from pastures in Taranaki and Northland and from pastures from three soil types in the Waikato. The lowest were in Northland (134.3 micromol/kg) and the highest in Taranaki (173.3 micromol/kg). Calculated dietary available copper levels showed the lowest were from pastures grown on organic soils in the Waikato. These soils also had high molybdenum levels. Serum copper values as received were lowest in Northland (7.30 micromol/l), and were marginal for both Taranaki (9.91 micromol/l) and the Waikato (9.93 micromol/l). The levels in supplemented herds were considerably higher, i.e. from the Waikato 11.7 micromol/l and from Taranaki 11.5 micromol/l. When liver and serum copper levels from paired samples were compared there was a reasonable correlation (r = 0.64) but the standard deviation approximated the mean liver copper level, i.e. 155 +/- 141 micromol/l. 相似文献
3.
During the past two decades with farmer participation in irrigation management moving to center stage, the traditional view of having a centralized control over the water resources for better management has changed. Nevertheless, success of irrigation management transfer depend on a whole set of institutional arrangements or the rules-in-use and the willingness of the users to comply and enforce and/or change the rules in the light of changing circumstances. There are many institutional analyses of water sector, much of them touch on law, policy and administration, and characteristics of the users. The present paper is based on the study carried out to examine the institutional arrangements in one of the water users association that was first in the Maharashtra state. It focuses on the institutional arrangements governing water use and distribution and attempts to elicit the perceptions of the members regarding the rules-in-use. The findings reveal that the WUA has been successful in devising and enforcing the rules for water distribution, fee collection and conflict resolution for over a decade. However, current socio-economic developments such as political heterogeneity have required explicit conflict resolution mechanisms. These issues have now become issues demanding immediate attention and may be use of existing courts or legal institutions to help the WUA sustain in future. 相似文献
4.
Deirdre B. Gleeson Anke M. Herrmann Stephen J. Livesley Daniel V. Murphy 《Applied soil ecology》2008,40(1):189-194
The objective of this study was to examine the relationship between soil water potential, nitrifier community structure and nitrification activity in semiarid soils. Soils were collected after a 5-month dry period (end of summer) and subsequently rewetted to specific water potentials and incubated for 7 days prior to analysis of nitrification activity and nitrifier community structure. The approach used in this study targeted a 491bp segment of the amoA gene which encodes the active site of the ammonia monooxygenase enzyme, which is the key enzyme for all aerobic ammonia oxidisers. amoA serves as a useful target for environmental studies since it is both specific and universal for all ammonia oxidisers and reflects the phylogeny of the ammonia oxidisers. Our results suggest that in semiarid soils water potential plays a key role in determining the structure of ammonia oxidising bacteria (AOB), and that additionally AOB community structure is correlated to potential nitrification rate in these soils. 相似文献
5.
Kemner KM Kelly SD Lai B Maser J O'loughlin EJ Sholto-Douglas D Cai Z Schneegurt MA Kulpa CF Nealson KH 《Science (New York, N.Y.)》2004,306(5696):686-687
High-energy x-ray fluorescence measurements were used to make elemental maps and qualitative chemical analyses of individual Pseudomonas fluorescens strain NCIMB 11764 cells. Marked differences between planktonic and adhered cells were seen in the morphology, elemental composition, and sensitivity to Cr(VI) of hydrated cells at spatial scales of 150 nm. This technology can be applied to natural geomicrobiological systems. 相似文献
6.
Surveillance data on the distribution of viral haemorrhagic septicaemia virus (VHSV) in the North Sea (UK), targeting Atlantic herring in areas with previous virus detection, were obtained from research cruises conducted during 2005. The sensitive molecular approach of real‐time RT‐PCR (qRT‐PCR) was applied alongside a newly developed endogenous positive control assay specific for herring (elongation factor 1α) to ensure integrity of template. Three hundred and five pools from 1937 individual herring were tested, and no evidence of VHSV in association with wild Atlantic herring was detected. Samples were obtained from Scottish waters where marine aquaculture is conducted. The results confirm that previous tissue culture studies have most likely not significantly underestimated the prevalence of carrier herring in this area. The significance of migratory species such as herring as a reservoir species for VHSV, with the potential to translocate virus genotypes between geographical areas, is discussed. 相似文献
7.
Anthocyanins and proanthocyanidins were characterized by HPLC-ESI-MS/MS coupled with a diode array and/or fluorescent detector in seven cultivars of Ribes nigrum (black currant) and Ribes rubrum (red currant, Red Lake), six cultivars of Ribes grossularia (gooseberries), Aronia melanocarpa(chokeberry), and Sambucus nigra (elderberry). Thirty-one different anthocyanins were detected in these berries, but not every anthocyanin was observed in each berry. A number of minor anthocyanins were identified from these berries for the first time. The concentrations of individual anthocyanins in all of the berries were quantified using relevant anthocyanidin 3-glucoside standards. Among the berries studied in this paper and in berries in general, chokeberry has the highest total anthocyanin concentrations [1480 mg/100 g of fresh weight (FW)], whereas the lowest total anthocyanin concentration in the berries studied was found in the gooseberry cv. Careless, which contained only 0.07 mg/100 g of FW. Two cultivars of gooseberries (Marigold and Leveller) did not contain any anthocyanins. Total proanthocyanidin concentrations in the berries studied ranged from 23 to 664 mg/100 g of FW in elderberry and chokeberry, respectively. Procyanidin or prodelphinidin polymers were the predominant components (>65% w/w) in most of the berries. The lipophilic and hydrophilic antioxidant capacities were measured by the oxygen radical absorbance capacity (ORAC(FL)) procedure. The total antioxidant capacity varied from 21 micromol of TE/g of FW in Careless gooseberry to 161 micromol of TE/g of FW in chokeberry. Total phenolics in the berries in general paralleled hydrophilic antioxidant capacity. 相似文献
8.
Joy DA Feng X Mu J Furuya T Chotivanich K Krettli AU Ho M Wang A White NJ Suh E Beerli P Su XZ 《Science (New York, N.Y.)》2003,300(5617):318-321
The emergence of virulent Plasmodium falciparum in Africa within the past 6000 years as a result of a cascade of changes in human behavior and mosquito transmission has recently been hypothesized. Here, we provide genetic evidence for a sudden increase in the African malaria parasite population about 10,000 years ago, followed by migration to other regions on the basis of variation in 100 worldwide mitochondrial DNA sequences. However, both the world and some regional populations appear to be older (50,000 to 100,000 years old), suggesting an earlier wave of migration out of Africa, perhaps during the Pleistocene migration of human beings. 相似文献
9.
10.
Results of a Preliminary Trial with Sphaerophorus necrophorus Toxoids to Control Liver Abscesses in Feedlot Cattle 总被引:1,自引:1,他引:0 下载免费PDF全文
M. M. Garcia D.C. Alexander K. A. McKay W. J. Dorward S. E. Magwood 《Canadian journal of veterinary research》1974,38(3):222-226
A preliminary field experiment was undertaken to evaluate the efficacy of alum precipitated toxoids of Sphaerophorus necrophorus prepared from sonicated whole cells and cell fractions to reduce the incidence of bovine abscesses. A total of 108 calves were divided into five groups and treated as follows: I. uninoculated control, II. adjuvant inoculated control, III. 15.5 mg protein of sonicated (fragmented cells) toxoid, IV. 10.5 mg protein of cytoplasmic toxoid. V. 15.5 mg protein of cytoplasmic toxoid. All animals were maintained under similar conditions to those prevailing in feedlots in Alberta. Livers were examined at slaughter. The most promising result was achieved with the injection of 15.5 mg protein of cytoplasmic toxoid. In this treatment group, no scars (healed lesions) were found in the liver and the incidence of liver abscesses was reduced to 10% from the average 35% liver abscesses and scars found in the uninoculated and adjuvant inoculated groups. The toxoid from sonicated whole cells did not reduce liver abscess incidence. These data suggest that the incidence of liver abscesses in cattle fattened in feedlots may be reduced by immunization. 相似文献