Comparison of fecal samples collected per rectum and off the ground for estimation of environmental contamination attributable to beef cattle

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.     

Re-Visiting Calcium Concentration and Distribution in Apple Fruit (Malus domestica Borkh.)

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.     

Water and Fertilizer Nitrogen Management to Minimize Nitrate Pollution from a Cropped Soil in Southwestern Quebec,Canada

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.     

Impacts of biodiversity loss on ocean ecosystem services

Human-dominated marine ecosystems are experiencing accelerating loss of populations and species, with largely unknown consequences. We analyzed local experiments, long-term regional time series, and global fisheries data to test how biodiversity loss affects marine ecosystem services across temporal and spatial scales. Overall, rates of resource collapse increased and recovery potential, stability, and water quality decreased exponentially with declining diversity. Restoration of biodiversity, in contrast, increased productivity fourfold and decreased variability by 21%, on average. We conclude that marine biodiversity loss is increasingly impairing the ocean's capacity to provide food, maintain water quality, and recover from perturbations. Yet available data suggest that at this point, these trends are still reversible.     

Gaseous and leaching nitrogen losses from no-tillage and conventional tillage systems following surface application of cattle manure

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.     

Comparison study of therapeutic results of closed tibial shaft fracture with intramedullary nails inserted with and without reaming

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.     

Endophyte effects on reproduction of a root-knot nematode (Meloidogyne marylandi) and osmotic adjustment in tall fescue

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.     

Global patterns of predator diversity in the open oceans

The open oceans comprise most of the biosphere, yet patterns and trends of species diversity there are enigmatic. Here, we derive worldwide patterns of tuna and billfish diversity over the past 50 years, revealing distinct subtropical "hotspots" that appeared to hold generally for other predators and zooplankton. Diversity was positively correlated with thermal fronts and dissolved oxygen and a nonlinear function of temperature (approximately 25 degrees C optimum). Diversity declined between 10 and 50% in all oceans, a trend that coincided with increased fishing pressure, superimposed on strong El Ni?o-Southern Oscillation-driven variability across the Pacific. We conclude that predator diversity shows a predictable yet eroding pattern signaling ecosystem-wide changes linked to climate and fishing.     

Ecosystem effects of invertebrate fisheries

Since the 1950s, invertebrate fisheries catches have rapidly expanded globally to more than 10 million tonnes annually, with twice as many target species, and are now significant contributors to global seafood provision, export, trade and local livelihoods. Invertebrates play important and diverse functional roles in marine ecosystems, yet the ecosystem effects of their exploitation are poorly understood. Using 12 ecosystem models distributed worldwide, we analysed the trade‐offs of various invertebrate fisheries and their ecosystem effects as well as ecological indicators. Although less recognized for their contributions to marine food webs, our results show that the magnitude of trophic impacts of invertebrates on other species of commercial and conservation interest is comparable with those of forage fish. Generally, cephalopods showed the strongest ecosystem effects and were characterized by a strong top‐down predatory role. Lobster, and to a lesser extent, crabs, shrimp and prawns, also showed strong ecosystem effects, but at lower trophic levels. Benthic invertebrates, including epifauna and infauna, also showed considerable ecosystem effects, but with strong bottom‐up characteristics. In contrast, urchins, bivalves, and gastropods showed generally lower ecosystem effects in our simulations. Invertebrates also strongly contributed to benthic–pelagic coupling, with exploitation of benthic invertebrates impacting pelagic fishes and vice versa. Finally, on average, invertebrates produced maximum sustainable yield at lower levels of depletion (~45%) than forage fish (~65%), highlighting the need for management targets that avoid negative consequences for target species and marine ecosystems as a whole.     

Nitrate nitrogen in the soil profile and drainage water as influenced by manure and mineral fertilizer application in a Barley–Carrot production system

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.