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1.
OBJECTIVES: To determine whether sampling feces off the ground replicates prevalence estimates for specific pathogens obtained from fecal samples collected per rectum of adult cows, and to determine characteristics of feces on the ground (fecal pats) that are associated with subsequent identification of Campylobacter spp, Cryptosporidium parvum, and Giardia duodenalis. ANIMALS: A random sample of adult beef cattle from 25 herds located throughout California. PROCEDURE: 1,115 rectal and ground fecal samples were obtained. Samples were submitted for culture of Campylobacter spp and examined, using a direct fluorescent antibody assay, to detect C parvum oocysts and G duodenalis cysts. Characteristics of fecal pats, such as volume and consistency, were recorded. RESULTS: Prevalence of Campylobacter spp was 5.0% (20/401) for rectal fecal samples, which was significantly greater than prevalence determined for ground fecal samples (2/402; 0.5%). Most isolates were C jejuni subsp jejuni. Prevalence of C parvum was higher in rectal fecal samples (6/557; 1.1%) than in ground fecal samples (1/558; 0.2%), but this difference was not significant. Prevalence of G duodenalis did not differ for rectal (36/557; 6.5%) versus ground (26/558; 4.7%) fecal samples. CONCLUSIONS AND CLINICAL RELEVANCE: Evaluation of ground fecal samples may not accurately indicate the prevalence of Campylobacter spp or C parvum in cattle but may reflect prevalence of G duodenalis. Differences in prevalence estimates between the 2 methods suggest inactivation of pathogens in feces after cattle have defecated. Prevalence estimates generated by evaluation of ground fecal samples, however, may more accurately estimate environmental pathogen burden.  相似文献   
2.
Distribution of calcium in the apple has been quantified using mineral analyses of fruit sections during the mid-1900s by various researchers. Most of the work was done either at harvest, or after storage. We used Proton-induced X-ray spectrometry (PIXE) and Scanning Electron Microscopy to correlate Ca distribution in apples to results obtained from mineral analyses (MA). For fruit at harvest transverse distribution of Ca in ‘Braeburn’ apples determined by PIXE confirmed similar analyses with MA. It was not possible to establish a significant relationship between the total Ca concentration determined by PIXE and soluble Ca concentration from MA in this paper, either at harvest, or 80 days after full bloom (dafb). A significant correlation was found between PIXE and SEM results 80 dafb.  相似文献   
3.
Nitrate-N (NO3 --N) pollution of water resources is a widely recognized problem. Water and nitrogen fertilizer are the two most important factors affecting NO3 --N movement to surface and groundwater. Field trials were conducted from 1998 to 2000 growing seasons to investigate the combined impacts of water table management (WTM) and N fertilization rate on NO3 --N concentration in the soil profile and in drain discharge. There were two water table treatments: free drainage (FD) with open drains at a 1.0 m depth from the soil surface and subirrigation (SI) with a target water table depth of 0.6 m below the soil surface, and two N fertilizer rates: 120 kg N ha-1 (N120) and 200 kg N ha-1 (N200) in a split-plot design. Compared to FD, SI reducedNO3 --N concentration in the soil by up to 50% averaged over the two N rates. Concentrations of NO3 --N in drainage water fromSI plots were lower than those from FD by 55 to 73%. These findings suggest that SI can be used as a means of reducing soil NO3 --N pollution and drainage water NO3 --N concentrations.  相似文献   
4.
Previous studies have demonstrated inconsistent results on the impact of tillage systems on nitrogen (N) losses from field-applied manure. This study assessed the impact of no-tillage (NT) and conventional tillage (CT) systems on gaseous N losses, N2O:N2O + N2 ratios and NO3-N leaching following surface application of cattle manure. The study was undertaken during the 2003/2004 and 2004/2005 seasons at two field sites in Nova Scotia namely, Streets Ridge (SR) in Cumberland County and the Bio-environmental Engineering Centre (BEEC) in Truro. Results showed that the NT system had higher (p < 0.05) NH3 losses than CT. Over the two seasons, manure incorporation in CT reduced NH3 losses on average by 86% at SR and 78% at BEEC relative to NT. At both sites and during both seasons, denitrification rates and N2O fluxes in NT were generally higher than in CT plots, presumably due to higher soil water and organic matter content in NT. Over the two seasons, mean denitrification rates at SR were 239 and 119 g N ha−1 d−1, while N2O fluxes were 120 and 64 g N ha−1 d−1 under NT and CT, respectively. At BEEC mean denitrification rates were 114 and 71 g N ha−1 d−1, while N2O fluxes were 52 and 27 g N ha−1 d−1 under NT and CT, respectively. Conversely, N2O:N2O + N2 ratios were lower in NT than CT suggesting more complete reduction of N2O to N2 under NT. When averaged across all soil depths, NO3-N was higher (p < 0.05) in CT than NT. Nitrate-N decreased with depth at both sites regardless of tillage. In most cases, NO3-N was higher under CT than NT at all soil depths. Similarly, flow-weighted average NO3-N concentrations in drainage water were generally higher under CT. This may be partly attributed to higher denitrification rates under NT. Therefore, NT may be a viable strategy to remove NO3-N from the soil, and thus, reduce NO3-N contamination of groundwater. However, it should be noted that while the use of NT reduces NO3-N leaching it may come with unintended environmental tradeoffs, including increased NH3 and N2O emissions.  相似文献   
5.
Tibia fractures are the most common type of long bone fractures in US. This study aimed at comparing the therapeutic results of closed tibial shaft fracture with intramedullary nails inserted with and without reaming. In this randomized clinical trial study, 60 patients with a fracture of the tibia were examined. The patients were randomly divided into two groups. Thirty patients treated through inserting intramedullary nail with reaming technique (group A). The other 30 patients treated through inserting intramedullary nail without reaming technique (group B). After operation physical examination and control radiography were taken up to 6 month and results were compared. Sixty patients suffering from closed tibial diaphysis fractures were studied. Mean age of the group A and B were 40.24 +/- 12.32 and 38.42 +/- 14.28, respectively. Group A consisted of 24 (80%) males and 6 (20%) females while group B consisted of 24% females and 76% males. Considering fracture based on OTA criteria (p = 0.4) and severity of soft tissue damage based on Tscherne classification (p = 0.6), there was no statistically meaningful difference between groups A and B. The study demonstrated that degree of horizontal displacement, mean time of surgery, post-operation infection, organ shortness at the end of the follow-up period, organ deviation in patients of the group A was significantly more than that of the group B. Time required for callus formation (mean time of union), mean time of full weight bearing time and mean time of return to normal activities in group B was significantly more than that of the group A.  相似文献   
6.
In a 2 × 2 × 2 factorial experiment, plants of one genotype of tall fescue ( Festuca arundinacea ) were grown in soil in pots in a glasshouse on two occasions. The treatments were either with (E+) or without (E–) infection by the fungal endophyte Neotyphodium coenophialum ; with (N+) or without (N–) inoculation by the root-knot nematode Meloidogyne marylandi ; and with or without water deficit stress. In the first experiment, nematode numbers after 5 weeks had increased 10 times in the E–/N– watered pots and 22 times in the E–/N+ stressed plants. Root dry weight was decreased in all E–/N+ pots, compared with E–/N–. In contrast, nematode numbers in all E+/N+ pots decreased to nearly zero and root dry weight was unaffected. Osmotic adjustment in the growing zone of stressed plants was –0·35 MPa in E–/N– pots, but only –0·10 MPa in E–/N+ pots. Osmotic adjustment was greatest (–0·64 MPa) in E+ pots of both nematode treatments and almost no nematodes survived in the N+ pots. In the second experiment, there was complete nematode mortality in the E+ pots. Plant water relations were unaffected by treatments, however. It is concluded that endophyte-enhanced persistence of tall fescue in M. marylandi -infested soils that are prone to drought may be explained at least partly by endophyte protection of roots from nematode damage. Nematode inhibition by the endophyte may operate in addition to direct influences of the endophyte on enhancing drought tolerance of the host.  相似文献   
7.
Nitrate-N (NO3 ?-N) is a ubiquitous pollutant in both surface and groundwater in many agro-ecosystems. This has elicited a concerted effort to identify management strategies that mitigate NO3 ?–N pollution, without compromising crop yield. This study was conducted on a field site located at the Bio-Environmental Engineering Centre (BEEC) in Truro, NS, Canada during 1999 and 2000. The site has been used since 1997 to investigate the relative effect of inorganic versus organic fertilizer (liquid hog manure; LHM) applied at rates (70 kg N ha?1) on NO3 ?-N leaching from a carrot rotation system. NO3 ?-N concentrations were monitored in both the soil profile and in tile drainage effluents from eight treatment plots. The LHM treatment elicited significantly (P < 0.01) higher soil NO3 ?-N concentrations than inorganic fertilizer (IF) in June and October during 1999, but not 2000. The sampling date and soil depth were significant in most cases. Annual flow weighted averages (FWA) of NO3 ?-N in drainage water were generally greater for plots receiving LHM (15.4 and 10.5 mg L?1 for 1999 and 2000, respectively), when compared to IF (8.9 and 6.0 mg L?1 for 1999 and 2000, respectively), but the difference was significant (P < 0.05) only in 1999. Maximum NO3 ?-N concentrations in drainage water were similar for both treatments, while the LHM treatment had a significantly higher percentage of samples that were > 10 mg L?1. The total NO3 ?-N load was greater for the LHM treatment when compared to the IF treatment in 1999. Barley and carrot yields were unaffected by treatment applications.  相似文献   
8.
The effects of corn particle size and dietary fibre on the performance, coefficient of apparent ileal digestibility (CAID) and intestinal characteristics in broiler starters fed pelleted diets were studied. The experiment included 10 treatments arranged as a 2 × 5 factorial with two corn particle sizes (GMD of 1071 [CGC] vs. 534 [FGC]) and five diets that consisted in a low-fibre diet and four extra diets resulting from the inclusion of insoluble fibre sources (10 g/kg of lignocellulose (LC), and 30 g/kg of oat hulls; OH, rice hulls; RH, and sunflower hulls; SFH). In coarse grinding, all-fibre sources improved body weight gain and feed intake compared to the control diet (p < 0.01). Feed conversion ratio (FCR) improved with fibre supplementation (p < 0.01) and fine grinding of corn (FGC) (p < 0.01). Coarse grinding of corn (CGC) and inclusion of RH, SFH and OH reduced gizzard pH (p < 0.01). Fibre inclusion increased ileal fat and Ca digestibility (p < 0.01), gizzard weight (p < 0.01), digesta transit time (p < 0.01) and length of duodenum and small intestine (p < 0.01). The CAID of phosphorus increased in CGC fed birds and inclusion of RH, SFH and OH (p < 0.05). The weight of gizzard, proventriculus and pancreas (p < 0.01) was greater in CGC fed birds. Feeding SFH, RH and OH (p < 0.01), and CGC (p < 0.01) increased the villus height (VH) of the duodenum. The OH, RH and SFH supplementation increased the caecal population of Lactobacillus spp. and total anaerobic bacteria (p < 0.01) only in FGC fed birds. Overall, birds fed pelleted diets containing RH, OH and SFH (3%) exhibited improved performance, and increased nutrient digestibility, which may be caused by developed gizzards and intestine. Furthermore, coarse grinding of corn is beneficial to gizzard development.  相似文献   
9.
Bitter pit in apples still causes significant losses, especially in the export markets of ‘Golden Delicious’ apples from South Africa. Orchard practices to reduce the possibility of bitter pit are followed, as well as destructive methods to predict the probability thereof, but the occurrence of bitter pit is still unacceptably high. Fluorescence imaging is a fast, non-destructive technique, able to evaluate numerous fruit within a short time span. By applying fluorescence imaging on individual fruit before any symptoms of bitter pit were apparent, lower fluorescence was shown to be associated with bitter pit development in apples in selective cases. Our results showed that, using averaged cumulative distribution functions (CDFs) of pitted and non-pitted fruit classes, it was possible to show a difference between these classes with fluorescence imaging. However, the individual distinction between all pitted and non-pitted fruit of our total sample, could not been defined as clearly.

In the majority of cases, on a single fruit basis, separation in groups was not satisfactory (less than 100% accurate) based on industry requirements for a prediction technique. Results of pre-harvest imaging on apples to identify fruit with bitter pit potential at harvest showed that pitted fruit were correctly classified (75–100%). However, misclassification of non-pitted fruit (50% and less) with fluorescence imaging is still too high to be of any commercial use.  相似文献   

10.
Pre-harvest foliar applications to increase fruit calcium (Ca) content and reduce bitter pit incidence, is a standard practice world wide. We re-evaluated the effectiveness of early season applications versus late applications of calcium nitrate (Ca(NO3)2) to reduce bitter pit in ‘Golden Delicious,’ under the present environmental conditions of the Western Cape, South Africa. Two periods of efficient uptake of external Ca were identified, viz., during cell division and the last few weeks before harvest. Foliar Ca applications during mid season (from 40 d after full bloom) were more effective in increasing fruit Ca content and reducing bitter pit incidence, than later applications. Thus, it is important to apply the bulk of the Ca(NO3)2 during the first few weeks after cell division to maximize the Ca content of ‘Golden Delicious’ apples.  相似文献   
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