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101.
Koontz HV Prince RP Koontz RF 《HortScience : a publication of the American Society for Horticultural Science》1987,22(3):424-425
Radiation from high-pressure sodium (HPS) lamps provided more than a 50% increased yield (fresh and dry weight of tops) of loose-leaf lettuce cultivars Grand Rapids Forcing and RubyConn, compared to that obtained by radiation from cool-white fluorescent (CWF) lamps at equal photosynthetic photon flux; yet, input wattage was approximately 36% less. It was postulated that the considerable output of 700 to 850 nm radiation from the HPS lamp was a significant factor of the increased yield. Under HPS lamps, the leaves of both cultivars were slightly less green with very little red pigmentation ('RubyConn') and slightly elongated, compared to CWF, but plant productivity per unit electrical energy input was vastly superior with HPS. 相似文献
102.
Koontz HV Prince RP Berry WL 《HortScience : a publication of the American Society for Horticultural Science》1990,25(6):707
A system was developed in which nutrient flow to plant roots is controlled by a thin (0.98 or 1.18 mm) porous (0.2 or 0.5 microns) stainless steel sheet membrane. The flow of nutrient solution through the membrane is controlled by adjusting the relative negative pressure on the nutrient solution side of the membrane. Thus, the nutrient solution is contained by the membrane and cannot escape from the compartment even under microgravity conditions if the appropriate pressure gradient across the membrane is maintained. Plant roots grow directly on the top surface of the membrane and pull the nutrient solution through this membrane interface. The volume of nutrient solution required by this system for plant growth is relatively small, since the plenum, which contains the nutrient solution in contact with the membrane, needs only to be of sufficient size to provide for uniform flow to all parts of the membrane. Solution not passing through the membrane to the root zone is recirculated through a reservoir where pH and nutrient levels are controlled. The size of the solution reservoir depends on the sophistication of the replenishment system. The roots on the surface of the membrane are covered with a polyethylene film (white on top, black on bottom) to maintain a high relative humidity and also limit light to prevent algal growth. Seeds are sown directly on the stainless steel membrane under the holes in the polyethylene film that allow a pathway for the shoots. 相似文献
103.
D. RUGG D. THOMPSON RP GOGOLEWSKI GR ALLERTON RA BARRICK JS EAGLESON 《Australian veterinary journal》1998,76(5):350-354
Objective To investigate the efficacy of ivermectin in an intraruminal controlled-release capsule (CRC) against blowfly strike.
Design Pen and field trials with controls.
Animals Pen studies: Two breech strike trials involving 60 Romney and 60 Merino sheep. One body strike trial using 100 Merino sheep.
Field trials: Eight trials in New Zealand used 1000 Romney and Romney-cross sheep. Fifty Merino lambs in one trial in Australia.
Procedure Pen studies: Sheep were allocated to two equal groups. One was not treated, the other sheep received a CRC that delivered ivermectin at 20 μg/kg/day for 100 days. In the breech strike trials, each animal was given an oral laxative 2 days before exposure to adult Lucilia cuprina . In the body-strike trial, the sheep sheep were kept wet to increase susceptibility prior to the release of blowflies.
Field trials: Fifty or 200 sheep allocated to equal groups of nontreated or treated with the CRC and grazed at pasture exposed to natural blowfly challenge.
Results Pen studies: Breech strikes developed in 24 of 60 controls but in none of 60 CRC-treated sheep. There was a 35% reduction in the number of CRC-treated sheep struck on the body.
Field trials: The average number of breech strikes in CRC-treated sheep was reduced by 86% (P < 0.001). The number of body strikes in the treated groups was a reduced by 27% (P < 0.05).
Conclusion The ivermectin CRC is a useful aid in controlling breech strike, but provides only moderate reduction in the incidence of body strike. 相似文献
Design Pen and field trials with controls.
Animals Pen studies: Two breech strike trials involving 60 Romney and 60 Merino sheep. One body strike trial using 100 Merino sheep.
Field trials: Eight trials in New Zealand used 1000 Romney and Romney-cross sheep. Fifty Merino lambs in one trial in Australia.
Procedure Pen studies: Sheep were allocated to two equal groups. One was not treated, the other sheep received a CRC that delivered ivermectin at 20 μg/kg/day for 100 days. In the breech strike trials, each animal was given an oral laxative 2 days before exposure to adult Lucilia cuprina . In the body-strike trial, the sheep sheep were kept wet to increase susceptibility prior to the release of blowflies.
Field trials: Fifty or 200 sheep allocated to equal groups of nontreated or treated with the CRC and grazed at pasture exposed to natural blowfly challenge.
Results Pen studies: Breech strikes developed in 24 of 60 controls but in none of 60 CRC-treated sheep. There was a 35% reduction in the number of CRC-treated sheep struck on the body.
Field trials: The average number of breech strikes in CRC-treated sheep was reduced by 86% (P < 0.001). The number of body strikes in the treated groups was a reduced by 27% (P < 0.05).
Conclusion The ivermectin CRC is a useful aid in controlling breech strike, but provides only moderate reduction in the incidence of body strike. 相似文献
104.
GR ALLERTON RP GOGOLEWSKI D. RUGG RE PLUE RA BARRICK JS EAGLESON 《Australian veterinary journal》1998,76(1):39-43
Objective To confirm the efficacy of ivermectin released from a controlled-release capsule administered to young sheep and to breeding ewes under field conditions. Design Randomised field trials. Procedure In each of ten field trials 25 weaned lambs were treated with ivermectin controlled-release capsules and 25 remained untreated. Eight similar field trials were conducted using adult ewes. Efficacy against infections of gastrointestinal nematodes was assessed by faecal egg counts and faecal larval culture. Body weights were recorded and faecal soiling of the breech wool (dags) was assessed. Results Nematode faecal egg counts in the two groups were not different (P = 0.13) before treatment in the weaner trials or before treatment in the ewe trials (P = 0.49), but thereafter eggs in the untreated sheep persisted, whereas counts in sheep given capsules were negligible (P ≤ 0.01). In the weaner trials, dag scores for the two groups were not different at the start of the trials (P = 0.18) but at the end, untreated sheep had significantly more dags (P = 0.04) than treated sheep. In the ewe trials, dag scores remained low in both groups. Weaners treated with the capsule gained 1.4 kg (95% CL: 0.7, 3.1) more weight over the 16 week trial period compared to untreated weaners (P = 0.01). Both groups of ewes lost weight as a result of parturition but the mean loss by week 16 was greater for untreated (3.7 kg) (95% CL: -5.1,-2.2) than for treated ewes (1.8 kg) (95% CL: -3.3, -0.4). The mean change in ewe body weight for the two groups was however not significant (P = 0.07). Differentiation of nematode larvae recovered from cultures of faeces from untreated animals indicated that the capsules were effective against the common parasites of sheep. Conclusion The capsule was efficacious against gastrointestinal nematodes judging from faecal egg counts. It has the potential to significantly reduce contamination of pasture with nematode eggs. Treated weaners had less dags for 16 weeks and gained more weight than untreated weaners. 相似文献
105.
RP Cervera MA Silvestre N Martí E García‐Mengual R Moreno M Stojkovic 《Reproduction in domestic animals》2010,45(5):e12-e20
Among the factors that affect the efficiency of somatic cell nuclear transfer (SCNT) in pigs, the activation protocol is the most variable among the current SCNT procedures. The aim of this study is focused on defining an efficient activation treatment of porcine oocytes. In Experiment 1, we studied the effects of nine different oocyte activation procedures (including chemical‐ and electrical‐based treatments) on parthenogenetic embryo development. In Experiment 2, we studied the effect of the more efficient activation procedures on the gene expression profile of Oct4 and Igf2r in parthenogenetic blastocysts. In conclusion, ionomycin as a first calcium stimulus is not able to activate porcine oocytes efficiently in comparison with electric procedures. Electrical treatments with 6‐DMAP significantly increased the level of Oct4 expression, whereas the single and double pulse treatments alone maintained the same profile as the IVF group. 相似文献
106.
Prince Leslie Leo L. Gowane G. R. Swarnkar C. P. Singh D. Arora A. L. 《Tropical animal health and production》2010,42(4):785-791
Genetic parameters for faecal egg count were estimated in naturally challenged Avikalin sheep developed and maintained at
Central Sheep & Wool Research Institute, Avikanagar, India, over a period of 4 years (2004–2007). The data on faecal egg count
for 433 animals descended from 41 sires, and 151 dams were used for the study. Genetic analyses were carried out using restricted
maximum likelihood, fitting an animal model and ignoring or including maternal genetic or permanent environmental effects.
Direct heritability for the trait was 0.149 ± 0.096 when maternal effects were ignored. In the model which takes in to account
direct genetic, maternal genetic and maternal permanent environment effect together, it was observed that maternal heritability
(m2) accounts for 0.6% of total variation whereas maternal permanent environmental effect (c2) accounts for 6.14% of total phenotypic variation. Effect of faecal egg count on the growth characteristics was observed
to be significant. It was seen that wherever FEC was high, body weight or average daily gain declined in active infective
stage. After termination of the infection, these effects were found to be non-significant. Result suggests that direct genetic
and maternal permanent environmental effects were important for this trait; thus, they need to be considered for improvement
in the trait. 相似文献
107.
REASONS FOR PERFORMING STUDY: Equine grass sickness is a dysautonomia characterised by widespread destruction of autonomic ganglia, resulting in the clinical signs of dysphagia, constipation, profuse sweating, tachycardia, rhinitis sicca and high mortality rate. Rhinitis sicca is a common finding in horses with the chronic form and we have postulated that alterations in autonomic innervation of the nasal mucosa might underlie this clinical presentation. OBJECTIVES: In this study, the expression and distribution of nerve fibres immunoreactive for calcitonin gene-related peptide (CGRP), substance P (SP), the general neuronal marker protein gene-product 9.5 (PGP 9.5; ubiquitin) and the intermediate neurofilaments (PAN-N; neurorfilaments L, M and H) in the nasal mucosa of normal horses (n = 10) and horses with EGS (n = 18; acute n = 8, subacute n = 3, chronic n = 7) was assessed. METHODS: Innervation density and distribution was investigated in the different groups using standard immunohistochemical techniques. RESULTS: Significant differences were noted when comparing the density and distribution of nerve fibres immunoreactive for PGP 95 and PAN-N, with PGP 95 consistently giving better staining in all groups and at all sites in the nasal mucosa. An apparent increase in the density of innervation was noted for acute vs. normal cases. A significant reduction in the density of innervation was noted only with PAN-N when comparing normal horses and acute cases with the chronic group (P < 0.05). CGRP and SP immunoreactive nerve fibres were typically most abundant in the epithelial and subepithelial layers, but the quality of staining and nerve fibre density was greater for SP, achieving significant difference in several comparisons. The density of innervation for SP was significantly reduced in the chronic group compared to the normal and acute groups (P < 0.01). A significant decrease was noted for CGRP only for the acute and chronic groups (P<0.05). CONCLUSIONS: These results demonstrate a reduction in the expression of the sensory neuropeptides in nasal mucosal innervation as a consequence of equine dysautonomia, and may underlie the clinical presentation of rhinitis sicca noted with this disease. POTENTIAL RELEVANCE: Nasal biopsy may be of use in antemortem diagnosis of grass sickness and identification of mucosal denervation; and might also be useful in the treatment of rhinitis in EGS cases. 相似文献
108.
Corcoran BM Mayhew IG Hahn CN Prince DR 《American journal of veterinary research》2000,61(12):1619-1624
OBJECTIVE: To determine the distribution of nerve fibers containing calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), and intermediate neurofilaments in nasal mucosa of horses. ANIMALS: 6 horses without evidence of nasal disease. PROCEDURE: Full-thickness nasal tissue specimens were obtained from the rostral portion of the nasal septum at necropsy, and fluorescence immunohistochemistry was performed to assess mucosal distribution of nerve fibers. RESULTS: Nerve fibers with CGRP-like immunoreactivity (CGRP-Li) formed a dense subepithelial network, and a large number of fibers were found coursing between epithelial cells. Fibers with CGRP-Li were also associated with blood vessels and mucous glands. Fibers with SP-like immunoreactivity (SP-Li) had a similar distribution and density. In contrast, there were few fibers with VIP-like immunoreactivity. Fibers containing intermediate neurofilaments were prominent and appeared as large nerve fiber bundles mainly adjacent to the nasal septum but also close to mucous glands and within the lamina propria. Intermediate neurofilaments were also identified in single nerve fibers at all sites, but the density of fibers with intermediate neurofilaments did not match that of fibers with CGRP- or SP-Li. CONCLUSIONS: The density and distribution of nerve fibers containing SP- or CGRP-Li in nasal mucosa of horses was similar to that reported for other species. However, expression of VIP in nerve fibers was low. Antibodies against intermediate neurofilaments identified many nerve fibers in nasal mucosa of horses but did not appear to identify small diameter fibers expressing SP or VIP. 相似文献
109.
Thalamocortical relay neurons: antidromic invasion of spikes from a cortical epileptogenic focus 总被引:18,自引:0,他引:18
Thalamocortical relay neurons whose axons project into a penicillininduced cortical epileptogenic focus generate bursts of action potentials during spontaneous interictal epileptiform discharges. These bursts originate in intracortical axons and propagate antidromically into thalamic neurons. Repetitive spike generation in cortical axons and presynaptic terminals could produce a potent excitatory drive and contribute to the generation of the large depolarization shifts which are seen in cortical elements during focal epileptogenesis. 相似文献
110.
Three experiments involving 304 pigs were conducted to determine the related effects of copper (Cu), calcium (Ca) and phosphorus (P) on the performance and liver Cu stores of growing-finishing pigs. Rate and efficiency of gain were improved by the addition of 250 ppm of Cu to the diets. Improvements in rate of gain averaged 6.6% (652 vs 696 g/d) to 60.5 kg body weight and 1.7% (713 vs 725 g/d) to 94.5 kg body weight. Feed:gain ratio was improved by 1.4% to 60.5 kg and 1.6% to 94.5 kg body weight when Cu was added to the diet. Increasing the dietary Ca and P levels from .65% Ca and .55% P to 1.2% Ca and .86 or 1.0% P resulted in increased (P less than .01) growth rate to 60 and 95 kg (649 vs 699 g/d and 700 vs 737 g/d, respectively), but feed efficiency was not affected (2.86 vs 2.84 and 3.18 vs 3.17 kg feed/kg gain, respectively.) Feeding the higher Ca and P levels resulted in increased liver Cu levels in pigs fed 250 ppm Cu (189 vs 323 ppm), but Ca and P did not affect liver Cu of pigs fed low Cu diets (29 vs 28 ppm). When dietary Ca and P were varied independently, the high Ca level increased liver Cu, but P had little effect on liver Cu. Increasing the dietary P level partially alleviated the effect of Ca on liver Cu. 相似文献