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31.
In order to clarify if a peri-parturient rise of Cryptosporidium parvum oocysts occurs in cows, faecal samples from 42 cows on two farms were collected. These samples were taken during the pre-parturient, the peri-parturient and the post-parturient periods. Two methods were used to detect the oocysts, a nested-PCR coupled with sequencing and a duplex real-time PCR (qPCR) that quantified Cryptosporidium spp. DNA concentration. The qPCR results were adjusted using a hierarchical Bayesian model taking into account within and between run variation. Generalised Estimating Equation models (GEE) were used to determine if peri-parturient cows were at greater risk of being infected than pre- or post-parturient cows. Fourteen dairy cows exhibited a peri-parturient and post-parturient rise in the excretion of Cryptosporidium spp. oocysts, other than the zoonotic C. parvum. The cows in the suckler beef farm were the only ones infected with the zoonotic species C. parvum at calving. Due to the low concentration of oocysts excreted mainly from species other than C. parvum, it would appear unlikely that cows act as a source of infection for their calves or contribute significantly to environmental contamination.  相似文献   
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Data from recent oceanographic cruises show that phytoplankton community structure in the Ross Sea is related to mixed layer depth. Diatoms dominate in highly stratified waters, whereas Phaeocystis antarctica assemblages dominate where waters are more deeply mixed. The drawdown of both carbon dioxide (CO2) and nitrate per mole of phosphate and the rate of new production by diatoms are much lower than that measured for P. antarctica. Consequently, the capacity of the biological community to draw down atmospheric CO2 and transport it to the deep ocean could diminish dramatically if predicted increases in upper ocean stratification due to climate warming should occur.  相似文献   
34.
Climate Change During the Last Deglaciation in Antarctica   总被引:1,自引:0,他引:1  
Greenland ice core records provide clear evidence of rapid changes in climate in a variety of climate indicators. In this work, rapid climate change events in the Northern and Southern hemispheres are compared on the basis of an examination of changes in atmospheric circulation developed from two ice cores. High-resolution glaciochemical series, covering the period 10,000 to 16,000 years ago, from a central Greenland ice core and a new site in east Antarctica display similar variability. These findings suggest that rapid climate change events occur more frequently in Antarctica than previously demonstrated.  相似文献   
35.
The humoral immune response was analysed in goats immunised with FhCL1, FhPrx, Sm14, and experimentally challenged with Fasciola hepatica. All immunised animals developed significant levels of anti-fluke specific antibodies and those immunised with FhCL1 showed the highest antibody titre. After experimental infection, an increase in the antibody level was detected only in goats immunised with FhCL1. In the adjuvant-control animals, the experimental challenge induced significant production of specific antibodies against FhCL1, FhPrx and Sm14. While liver fluke specific humoral responses were seen in all groups, no significant protection in any of the vaccinated groups was found.  相似文献   
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This study was conducted to measure the concentration of cefquinome in the endometrium of mares after intrauterine treatment and to evaluate associated inflammation. Mares (n = 14) were randomly assigned to one of the following groups: (i) control (n = 4) were either not treated (n = 2) or received (n = 2) lactated Ringer's intrauterine for 1 or 3 days; (ii) treated mares (n = 10) received intrauterine cefquinome for 1 or 3 days. After at least 10 days had passed following the last treatment and ovulation, mares were given Prostaglandin F2α (PGF2α) and were randomly assigned to an alternate treatment. Endometrial biopsy samples were taken at 2, 8, 24 and 48 h, or at 4, 12 and 36 h, after the last treatment. Biopsy samples were taken at the same time points from control mares (n = 2) and lactated Ringer-treated mares (n = 2). Cefquinome concentrations were quantified using a high-performance liquid chromatography (HPLC) assay and inflammation was assessed using haematoxylin and eosin (H&E)-stained sections. Concentrations of cefquinome [559 (1 day) and 595 μg/g (3 days) at 2 h, and 403 (1 day) and 370 μg/g (3 days) at 4 h] were similar between treatment groups at 2 and 4 h after treatment (p > 0.05). At 8 h, as well as at 24 and 48 h, concentrations were greater in the 3-day group (17 vs 301 μg/g, 3 vs 80 μg/g and 0.1 vs 0.2 μg/g, respectively) (p < 0.05). No significant differences (p > 0.05) in the inflammatory response at 2–48 h after treatment were found between groups.  相似文献   
37.
Fear and anxiety have been studied extensively in humans and other animals. However, far less attention has been focused on the clinical and ethical implications of nonhuman animals’ susceptibility to psychological disorders. Behavioral signs of psychopathology in nonhuman animals, including our closest phylogenetic relatives, are rarely described as clinical syndromes. In this study, we drew on approaches described in child psychiatry, veterinary medicine, and primatology, to identify behavioral clusters in chimpanzees comparable with human anxiety disorders, such as generalized anxiety disorder and obsessive–compulsive disorder.In phase 1 of this study, we accessed published case reports of 20 chimpanzees subjected to maternal separation, social isolation, experimentation, or similar experiences. We tested the inter-rater reliability of the Diagnostic and Statistical Manual of Mental Disorders (fourth edition; DSM-IV) criteria for generalized anxiety disorder and obsessive–compulsive disorder when applied to chimpanzees in these case studies. Additionally, based on the DSM-IV, veterinary approaches, and ethograms, we defined behaviorally anchored alternative criteria, which proved more reliable than the DSM-IV criteria in phase 1. In phase 2, the new behaviorally anchored criteria were applied to chimpanzees living in wild sites in Africa (n = 196) and those with previous histories of experimentation, orphanage, illegal seizure, or violent human conflict (n = 168) living in sanctuaries. In phase 2, 18% of chimpanzees living in sanctuaries met the set of behaviorally anchored criteria for generalized anxiety disorder, compared with 0.5% of those in the wild (P = 0.036), and 19% of chimpanzees in sanctuaries met the set of behaviorally anchored criteria for obsessive–compulsive disorder, compared with 0% of those in the wild (P = 0.071).Chimpanzees display behavioral clusters similar to anxiety disorders described in humans, underscoring the importance of ethical considerations regarding their use in experimentation and other captive settings.  相似文献   
38.
The rise of the angiosperms: a genecological factor   总被引:1,自引:0,他引:1  
In the primitive angiosperms, closed carpels are believed to have evolved as protection for ovules, which would otherwise be injured by animal pollinators. The hypothesis is presented that, whatever the origin and other functions of angiosperms, insect pollination and closed carpels may, in combination, reduce the influence of random variation on pollen tube competition, thus enhancing the ability of natural selection to act on the gametophytic phase of the life cycle. The microgametophytic phase represented by vast numbers of haploid individuals can then serve, by insect pollination and closed carpels, as a screen against any genome not functioning with a high degree of metabolic vigor. Poorly balanced genomes could thus be eliminated at relatively little cost. Insect-pollinated angiosperms would therefore benefit from positive aspects of sexual recombination. Such a system may have allowed the angiosperms to undergo their rise to dominance.  相似文献   
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A gelatin bolus containing the infective stage of Fasciola hepatica was prepared and administered to adult cattle. The bolus was formed to fit into the nozzle of a standard size bolus-type dosing gun. Administration proved easy and effective causing minimal stress to the animal, yet ensuring that experimental infection took place.  相似文献   
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