Understanding physical clogging in drip irrigation: in situ,in-lab and numerical approaches     

Salim Bounoua  Séverine Tomas  Jérôme Labille  Bruno Molle  Jacques Granier  Pierre Haldenwang  Surani Nuur Izzati 《Irrigation Science》2016,34(4):327-342

Dripper clogging is a major drawback of microirrigation systems that must be addressed to improve their efficiency and durability. Particle-induced clogging is first studied in situ. The experiments consist in observing in real conditions the behavior of a series of drippers fitted on an agricultural plot in the south of France. The plot is supplied from a canal with Durance River water. The latter is loaded with sediments that gradually clog drippers and filters. Water analysis reveal that physicochemical clogging prevails over biological clogging. This characterization helps in setting in-lab experiment protocol. Indeed, besides field observation of clogging, laboratory analyses of both the irrigation water and the clogging material are performed with reactive and inert clay: smectite and an illite–calcite mix. A surprising tendency is observed: Salt concentration in smectite seeded water decreases the clogging, whereas it increases agglomerate size. Computational fluid dynamic simulations are carried out to investigate the impact of particles on flow behavior. Results demonstrate that clay particles interacting with the flow govern the complex structure of the fluid velocity fields inside the dripper labyrinth channel.  相似文献   

QTL mapping of a partial resistance to the corn delphacid‐transmitted viruses in Lepidopteran‐resistant maize line Mp705     

Jacques A. Dintinger  Sylvia Salgon  Bernard Reynaud 《Plant Breeding》2014,133(1):19-27

A partial resistance to maize mosaic virus (MMV) and maize stripe virus (MStV) was mapped in a RILs population derived from a cross between lines MP705 (resistant) and B73 (susceptible). A genetic map constructed from 131 SSR markers spanned 1399 cM with an average distance of 9.6 cM. A total of 10 QTL were detected for resistance to MMV and MStV, using composite interval mapping. A major QTL explaining 34–41% of the phenotypic variance for early resistance to MMV was detected on chromosome 1. Another major QTL explaining up to 30% of the phenotypic variation for all traits of resistance to MStV was detected in the centromeric region of chromosome 3 (3.05 bin). After adding supplementary SSR markers, this region was found to correspond well to the one where a QTL of resistance to MStV already was located in a previous mapping study using an F₂ population derived from a cross between Rev81 and B73. These results suggested that these QTL of resistance to MStV detected on chromosome 3 could be allelic in maize genome.  相似文献   

Expression of conserved mucin domains by epithelial tissues in various mammalian species     

Lacunza E  Bara J  Segal-Eiras A  Croce MV 《Research in veterinary science》2009,86(1):68-478

Mucins are related to infectious and non-infectious diseases in Veterinary and Human Medicine. MUC1 mucin is a transmembrane glycoprotein expressed on the apical surface of human epithelia while MUC5AC is the predominant secreted mucin expressed in human gastric epithelium and goblet cells of lung and eyes. MUC5AC C-terminus cysteine rich regions and the cytoplasmic tail of MUC1 domains are conserved among several mammalian species. Objective: to compare the expression of MUC1 and MUC5AC mucins in mammalian epithelia. CT33 anti-MUC1 cytoplasmic tail (MUC1CT) polyclonal antibody and 45M1 anti-MUC5AC monoclonal antibody were employed. By immunohistochemistry, MUC1CT was expressed in most tissues while MUC5AC was restricted to gastric surface epithelium and goblet cells from trachea and lung. By western blot, MUC1CT showed a band at approximately 35 kDa in most tissues; MUC5AC revealed bands at >180 kDa in stomach and lung secretions from rat, cat, pig and cow. When rat MUC5AC was immunoprecipitated, a band at about 180 kDa was obtained.  相似文献   

Laminin receptor 1 is differentially expressed in thoracic and limb wounds in the horse     

Vincenzo Miragliotta  Jacques G. Lussier†  Christine L. Theoret† 《Veterinary dermatology》2009,20(1):27-34

Healing of wounds located on the distal limbs of horses is often complicated by retarded epithelialization and the development of exuberant granulation tissue (proud flesh). Treatments that definitively resolve this pathological process are still unavailable. Molecular studies of the repair mechanism might contribute to the development of new therapeutic strategies. The study presented herein aimed to clone the full length cDNA and to study the spatio-temporal expression profile of mRNA and protein for LAMR1, previously attributed a role in wound epithelialization, during the repair of body and limb wounds in the horse. Cloning was achieved by screening a cDNA library previously derived from 7-day wound biopsies. Expression was studied in unwounded skin and in samples from 1-, 2-, 3-, 4- and 6-week-old wounds of the body and limb. Temporal gene expression was determined by real time polymerase chain reaction (RT-PCR) while protein expression was mapped immunohistochemically. Full-length cDNA for equine LAMR1 was shown to be highly similar to that of other species. The mRNA expression of LAMR1 was significantly up-regulated only in thoracic wounds, 4 and 6 weeks following wounding (upon epithelialization). Cutaneous wounding induced protein expression at both locations. Our data suggest that up-regulation of LAMR1 protein might favour epithelialization during wound healing. However, its interaction with ligands other than laminin complicates data interpretation. Future studies should quantitatively verify the temporal expression of this protein in order to provide the basis for targeted therapies that might enhance epithelialization.  相似文献   

Comparison of postharvest changes in mango (cv Cogshall) using a Ripening class index (Rci) for different carbon supplies and harvest dates     

Jacques Joas  Yanis Caro  Mathieu Lechaudel 《Postharvest Biology and Technology》2009,54(1):25-31

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Effect of Crude Palm Oil Incorporation on Growth,Survival, Feed Efficiency,and Body Composition of Heterobranchus longifilis Fingerlings     

Athanase K. Otchoumou  Yao L. Alla  Genevieve Corraze  Sebastien L. Niamke  Jacques K. Diopoh 《Journal Of Applied Aquaculture》2013,25(2):169-178

An 8-week feeding trial was carried out to determine the effect of increasing dietary palm oil levels on African catfish juvenile growth and nutrient utilization. Six isonitrogenous diets were formulated to contain 0.5% to 15% crude palm oil with dietary lipid levels ranging from 5% to 20%. Growth performance and protein utilization efficiency of African catfish responded in a positive manner to palm oil addition up to 9% (diet 14% lipid). No further improvement in growth was observed with higher levels of palm oil in the diets, and lower survival was observed with inclusion of 15% palm oil (diet 20% lipid). Whole-body lipid content increased when fish were fed with increasing levels of dietary lipid. Under our experimental conditions, the best growth rate and nutrient utilization were observed with the inclusion of 9% crude palm oil in the diets for African catfish.  相似文献   

Agronomic performance of no-tillage relay intercropping with maize under smallholder conditions in Central Brazil     

Alpha Bocar Baldé  Eric ScopelFrançois Affholder  Marc Corbeels  Fernando Antonio Macena Da SilvaJosé Humberto Valadares Xavier  Jacques Wery 《Field Crops Research》2011,124(2):240-251

In the context of conservation agriculture on small scale farms of the Brazilian Cerrado, we hypothesized that planting a cover crop in relay with a commercial crop improves the efficiency of use of available natural resources, increasing biomass for use as fodder without reducing the grain yield of the main crop. The objective of this study was to measure the performance of two intercropped systems in terms of total above-ground biomass production and maize (Zea mays) grain yield: pigeon pea (Cajanus cajan) and Brachiaria (Brachiaria ruziziensis) sown as cover crops in established maize under a no-tillage management. The cover crops were sown at two different dates and a comparison was made with the three crops sown as a sole crop at the early sowing date. The experiment was conducted during the 2007-2008 and 2008-2009 growing seasons. Maize grain yield was not reduced by the presence of the relay cover crops in comparison with maize as the sole crop, even when the cover crop was sown soon after maize emergence. In contrast, the production of above-ground biomass by the cover crop was significantly lower when grown with maize than it was when grown as a sole crop. In the intercropped systems, when sown early, the cover crop produced higher total biomass than when sown late. Total above-ground biomass production of maize intercropped with a cover crop was much higher than that of any of the crops sown alone: the total biomass (average of the two growing seasons) produced by maize and pigeon pea was more than double that of maize grown alone. The land equivalent ratio (LER) of maize grain yield and biomass production was higher than one whatever the intercropped system used. It was particularly high when maize was intercropped with early sown pigeon pea; grain yield LER and biomass LER reaching, respectively, 1.72 and 1.73 in 2007-2008 and 2.02 and 2.03 in 2008-2009. These high LER values provide evidence for the complementary and the high efficiency of use of available resources by the intercropped plants and thus the advantage of such systems to produce both maize grain and cover crop forage under the conditions of our study.  相似文献   

The present and future of withdrawal period calculations for milk in the European Union: dealing with data below the limit of quantification          下载免费PDF全文

J. Henri  A.‐M. Jacques  P. Sanders  A. Chevance  M. Laurentie 《Journal of veterinary pharmacology and therapeutics》2017,40(2):116-122

The assessment of withdrawal periods for milk is affected by the occurrence of data below the lower analytical quantification limit (BLQ data) and the resulting uncertainty. The current regulatory approach for dealing with BLQ residues is simple and easy: BLQ data (and missing data) are arbitrarily reassigned a value of one‐half the LOQ before any calculation on the data with one of the three currently applicable methods. Here, we reconsider the determination of the withdrawal period of milk with data below the limit of quantification. Theoretical background on analytical limits and pharmacometric considerations will be established. Then, we analyze the uncertainty problems caused by the current approach and propose a calculation solution (maximum‐likelihood estimation handling left‐censored data) included in nonlinear mixed‐effects modeling. Finally, we illustrate this issue using a case example.  相似文献   

Prevalence and associated risk factors of mycobacterial infections in slaughter pigs from Mubende district in Uganda     

Adrian Muwonge  Clovice Kankya  Jacques Godfroid  Berit Djonne  John Opuda-Asibo  Demelash Biffa  Takele Ayanaw  Musso Munyeme  Eystein Skjerve 《Tropical animal health and production》2010,42(5):905-913

To date, the public health relevance of mycobacterial infections in pigs is not well investigated despite high risk of infection. Recently, there has been a documented increase in opportunistic infections and risk of acquiring opportunistic mycobacterial infections in HIV/AIDS patients in Mubende district; unfortunately, there has been no published information on the epidemiology of mycobacterial infections in this area. This study was carried out between September 2008 and February 2009. Investigations were done to assess the prevalence and associated risk factors of mycobacterial infections in slaughtered pigs in Mubende district of Uganda. A total of 997 pigs (53.7% male and 46.3% female) from 31 different slaughterhouses were examined for the presence of lesions compatible with TB and mycobacterial infections. Pathologic tissue specimens were collected for culturing and isolation of mycobacteria. A cross-sectional technique was used based on convenient visits to slaughterhouses but random selection of individual slaughtered pigs for a detailed post-mortem inspection on a daily basis. The results reflected a 9.3% and 3.1% (95% CI) prevalence of Mycobacterium species based on necropsy examinations and culture isolation, respectively. The highest prevalence of mycobacterial infection was recorded in Buwekula County (the mixed agro-zone) whilst the lowest was in Kassanda County (pastoral zone). A multivariable logistical regression analysis identified age (P ≤ 0.001) and sex (P ≤ 0.05) as risk factors for mycobacterial infections in pigs. Post-estimation statistics of the regression model evaluation and validation fit it well into the data (HL, χ ² = 5.9; P = 0.69 for necropsy, HL χ ² = 2.9; P = 0.94 for culturing). This study documented a high prevalence of mycobacterial infections in slaughter pigs in Mubende district. The fact that pigs and human often share common housing and environment poses a high risk of zoonotic transmission. This then warrants further molecular investigation to identify the specific Mycobacterium species and their public health importance in this area.  相似文献   

Organic residue mass at planting is an excellent predictor of tree growth in Eucalyptus plantations established on a sandy tropical soil     

Jean-Paul Laclau  Joseph Levillain  Philippe Deleporte  Jean de Dieu Nzila  Jean-Pierre Bouillet  Laurent Saint André  Antoine Versini  Louis Mareschal  Yann Nouvellon  Armel Thongo M’Bou  Jacques Ranger 《Forest Ecology and Management》2010

Tropical plantation forests are meeting an increasing proportion of global wood demand and comprehensive studies assessing the impact of silvicultural practices on tree and soil functioning are required to achieve sustainable yields. The objectives of our study were: (1) to quantify the effects of contrasting organic residue (OR) retention methods on tree growth and soil nutrient pools over a full Eucalyptus rotation and (2) to assess the potential of soil analyses to predict yields of fast-growing plantations established on tropical sandy soils. An experiment was set up in the Congo at the harvesting of the first rotation after afforestation of a native herbaceous savanna. Six treatments were set up in 0.26 ha plots and replicated in 4 blocks, with OR mass at planting ranging from 0 to 46.5 Mg ha⁻¹. Tree growth over the whole rotation was highly dependent on OR management at planting. Over-bark trunk volume 7 years after planting ranged from 96 m³ ha⁻¹ in the treatment with forest floor and harvest residue removal at planting to 164 m³ ha⁻¹ in the treatment with the largest amount of OR. A comparison of nutrient stocks within the ecosystem at planting and at the end of the rotation suggested that nutrient contents in OR were largely involved in the different response observed between treatments. OR management treatments did not significantly modify most of the nutrient concentrations in the upper layers of the mineral soil. Conventional soil analyses performed before planting and at ages 1 and 3 years were unable to detect differences between treatments despite large differences in tree growth. In contrast, linear regressions between stand aboveground biomass at harvesting and OR mass at planting (independent variable) showed that OR mass was an excellent predictor of stand yield (R² = 0.99). A large share of soil fertility comes from organic material above the mineral soil in highly weathered sandy soils and OR mass at planting might be used in conjunction with soil analyses to assess the potential of these soils to support forest plantations.  相似文献