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71.
The hydraulic performance of canals designed to deliver water by proportional allocation is highly dependent on the accuracy of construction of water division structures. If construction is inaccurate then inequity of water delivery is built into the system from the onset. A survey of hydraulic performance of Kalpnai distributary in NWFP Pakistan immediately after construction showed that the canal could only deliver 90% of designed discharge due to deficiencies in construction of two siphons, and that the tail end of the canal only received 70% of designed discharge. When operated at 70% of design discharge tail end reaches received 50% of designed discharge. Measurements of outlet structures showed that 57% of structures were built as intended and had not been damaged. All orifice outlets delivered more than 115% of design discharge and on average delivered 40% more than intended. Only 20% of open flumes were within 10% of design width, while 58% were more than 30% wider. As a result of these construction defects many watercourses were able to obtain much higher discharges than intended. The lack of control gates means there is no managerial remedy to redress the existing inequity. The only solution is to reconstruct a high proportion of outlet structures. Potential causes of poor construction are many, including lack of involvement of the agency responsible for subsequent operation, lack of dialogue with water users, and lack of accountability built into the project framework. 相似文献
72.
Cyanobacteria often produce severe illness and in some cases spectacular fatality on livestock and wildlife world-wide. Heavy cyanobacterial waterblooms usually form patches of dense surface scum, and terrestrial animals drinking such concentrated dirty froth can consume a fatal dose. Surprisingly, animals do not avoid swallowing concentrated microbial scum. Different experiments of drink selection were performed with laboratory mice to determine why animals drink these concentrated scum. These experiments showed that animals elected to consume dense cultures of the toxic cyanobacteria Microcystis aeruginosa in preference to limpid water. When M. aeruginosa cells were supplied ad libitum, mice avidly swallowed these toxic cyanobacteria until this led to their death. Mice were unable to detect the phycotoxin (microcystin). In contrast, mice did not select cultures containing other non-toxic phytoplanktonic organisms. Observations in nature suggest that this preference in the consumption of toxic cyanobacteria is common among other animal species. 相似文献
73.
Tracking escaped Atlantic cod (Gadus morhua L.) aggregated around Norwegian farms: Considerations for management strategies
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R. D. Hedger R. M. Serra‐Llinares P. Arechavala‐Lopez R. Nilsen P. A. Bjørn I. Uglem 《Fisheries Management and Ecology》2017,24(4):265-273
To examine site fidelity and potential for ecosystem impacts, 20 escapee cod (Gadus morhua L.) from fjord‐based cod farms were tagged with acoustic transmitters, released in the vicinity of the same farm, and their subsequent behaviour and survival monitored using a fixed array of acoustic receivers. Most individuals demonstrated high fidelity to their farm where tagged, and this increased during the polar night. Only five individuals (25%) were occasionally detected at another farm (4 km distance), and only three cod (15%) migrated out of the fjord during the 6‐month study period. Vertical movements were consistently greater in the hours around noon than at night, a behaviour inconsistent with that observed for wild fish. A high mortality rate (40%) was observed during the first 4 months post‐release, and actual mortality may have been even higher, limiting the potential for negative ecosystem effects from cod escapees. Findings from this study are used to discuss the development of recapture strategies for minimising potential impacts from cod escapees to ensure sustainable farming activity. 相似文献
74.
Meghan OGrady Milbrath Peter Daniel Fowler Samuel K Abban Dawn Lopez Jay D Evans 《Journal of insect science (Online)》2021,21(6)
One of the most serious bacterial pathogens of Western honey bees (Apis mellifera Linnaeus [Hymenoptera: Apidae]) is Melissococcus plutonius, the cause of the disease European foulbrood. Because European foulbrood is highly variable, with diverse outcomes at both the individual and colony levels, it is difficult to diagnose through visual inspection alone. Common lab diagnostic techniques include microscopic examination and molecular detection through PCR. In 2009, a lateral flow device was developed and validated for field diagnosis of European foulbrood. At the time, M. plutonius was thought to be genetically homogenous, but we have subsequently learned that this bacterium exists as multiple strains, including some strains that are classified as ‘atypical’ for which the lateral flow device is potentially less effective. These devices are increasingly used in the United States, though they have never been validated using strains from North America. It is essential to validate this device in multiple locations as different strains of M. plutonius circulate in different geographical regions. In this study, we validate the field use of the lateral flow device compared to microscopic examination and qPCR on larval samples from 78 commercial honey bee colonies in the United States with visual signs of infection. In this study, microscopic diagnosis was more sensitive than the lateral flow device (sensitivity = 97.40% and 89.47%, respectively), and we found no false positive results with the lateral flow device. We find high concurrence between the three diagnostic techniques, and all three methods are highly sensitive for diagnosing European foulbrood. 相似文献
75.
Spread of the yellow‐legged hornet Vespa velutina nigrithorax du Buysson (Hymenoptera: Vespidae) across Northern Spain
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A. Goldarazena I. P. de Heredia P. Romon J. C. Iturrondobeitia M. Gonzalez S. Lopez 《EPPO Bulletin》2015,45(1):133-138
The yellow‐legged hornet Vespa velutina nigrithorax du Buysson (Hymenoptera: Vespidae) is an Asian native species which has now established in parts of Europe. Since its detection in France in 2005 it has spread quickly across the country and also spread to the Iberian Peninsula. This paper compiles the most recent data about its spread and distribution on the Spanish mainland. The efficacy of using Véto‐Pharma© traps as a control method is also discussed. 相似文献
76.
Antonio Paoli Tatiana Moro Gerardo Bosco Antonino Bianco Keith A. Grimaldi Enrico Camporesi Devanand Mangar 《Marine drugs》2015,13(2):996-1009
Background: the ketogenic diet (KD) has become a widely used nutritional approach for weight loss. Some of the KD’s positive effects on metabolism and cardiovascular risk factors are similar to those seen after n-3 polyunsaturated fatty acids (ω-3) supplementation. We hypothesized that a ketogenic Mediterranean diet with phytoextracts combined with ω-3 supplementation may have increased positive effects on cardiovascular risk factors and inflammation. Methods: We analyzed 34 male overweight subjects; aged between 25 and 65 years who were overall healthy apart from overweight. The subjects followed a ketogenic diet protocol for four weeks; with (KDO3) or without (KD) ω-3 supplementation. Results: All subjects experienced a significant loss of body weight and body fat and there was no significant differences between treatment (body weight: KD—4.7 kg, KDO3—4.03 kg, body fat KD—5.41 kg, KDO3—5.86 kg). There were also significant decreases in total cholesterol, LDL-c, and glucose levels. Triglycerides and insulin levels decreased more in KDO3 vs. KD subjects, with a significant difference. All the investigated inflammatory cytokines (IL-1β, IL-6, TNF-α) decreased significantly in KDO3 subjects whilst only TNF-α showed a significant decrease in KD subjects over the 12 month study period. No significant changes were observed in anti-inflammatory cytokines (IL-10 and IL-1Ra), creatinine, urea and uric acid. Adiponectin increased significantly only in the KDO3 group. Conclusions: ω-3 supplementation improved the positive effects of a ketogenic Mediterranean diet with phytoextracts on some cardiovascular/metabolic risk factors and inflammatory state. 相似文献
77.
Rodolfo Enrique del Rio‐Rodriguez Atahualpa Sosa‐Lopez Daniel Pech 《Aquaculture Research》2014,45(5):907-912
This study presents an Ex‐Post Facto analysis of diseases of wild juvenile and adults of Litopenaeus setiferus collected from a field survey at the Natural Protected Area of Terminos lagoon, southern Mexico. The objective of the present approach was to determine if sampling site and/or shrimp age were contributing risk factors for disease between juvenile and adult shrimp; if there was a determined period of time in a year cycle when diseases were more critical, and if the analysis would help to decision‐ making considering what population would pose less risk of disease‐carrying when withdrawn for experimental purposes; all under an after‐the‐fact (ex‐post facto) approach. We identified that juvenile shrimp were at more risk of contracting some diseases in the estuarine environment and June, July and August months, were found to be a critical period when colonizing and parasitic diseases maintained a significant high prevalence in the shrimp population. These assumptions may help for decision‐making when wild shrimp have to be withdrawn from their natural environment for research purposes. 相似文献
78.
Christiana M. Glover Lisa M. Miller Noel O. Dybdal Alfonso Lopez Wendy M. Duckett Dianne McFarlane 《Journal of Equine Veterinary Science》2009
The objective of this study was to describe the histopathologic changes observed in extrapituitary organs as well as the pituitary glands of horses with pituitary pars intermedia dysfunction (PPID). Adrenal gland, thyroid gland, liver, lung, kidney, heart, and pituitary gland from 32 horses with clinical and histologic evidence of PPID and 20 control horses were reviewed histologically. Ten of the control horses were aged animals (≥15 years), allowing those changes attributed to age to be identified. In addition to previously reported changes in adrenal gland and liver, an association was established between PPID and several extrapituitary histopathologic changes, namely bronchiolitis, proliferative glomerulopathy, and myocardial lipofuscinosis and fibrosis. The potential biologic significance of these changes is discussed and, although the retrospective design of the current study precludes establishment of causal relationships between the observed extrapituitary changes and PPID, these findings suggest that further investigations are warranted. 相似文献
79.
Chalinulasterol (1) a new chlorinated sterol disulfate was isolated from the Caribbean sponge Chalinula molitba. Its structure was elucidated using mass spectrometry and NMR experiments. The possible role of chalinulasterol as modulator of the PXR nuclear receptor was investigated but, in spite of the close structural relationship with the PXR agonist solomonsterol A (2), it showed no activity. The structural requirements for the PXR nuclear receptor activity were discussed. 相似文献
80.
Biological Variability in Serum Cortisol Concentration Post‐adrenocorticotropic Hormone Stimulation in Healthy Dogs
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