Estimation of variance components including competitive effects of Large White growing gilts     

Arango J  Misztal I  Tsuruta S  Culbertson M  Herring W 《Journal of animal science》2005,83(6):1241-1246

Records of on-test ADG of Large White gilts were analyzed to estimate variance components of direct and associative genetic effects. Models included the effects of contemporary group (farm-barn-batch), birth litter, pen group, and direct and associative additive genetic effects. The area of each pen was 14 m2. The additive genetic variance was a function of the number of competitors in a group, the additive relationships between the animal performing the record and its pen mates, and the additive relationships between pen mates. To partially account for differences in the number of pen mates, a covariable (qi = 1, 1/n, or 1/n(1/2)) was added to the associative genetic effect. There were 4,946 records from 2,409 litters and 362 pen groups. Pen group size ranged from 12 to 16 gilts. Analyses by REML converged very slowly. A grid search showed that the likelihood function was almost flat when the additive genetic associative effect was fitted. Estimates of direct and associative heritability were 0.15 and 0.03, respectively. Within the BLUPF90 family of programs, the mixed-model equations can be set up directly. For variance component estimation, simple programs (REMLF90 and GIBBSF90) worked without modifications, but more optimized programs did not. Estimates obtained using the three values of qi were similar. With the data structure available for this study and under an environment with relative low competition among animals, accurate estimation of associative genetic effects was not possible. Estimation of competitive effects with large pen size is difficult. The magnitude of competition effects may be larger in commercial populations, where housing is denser and food is limited.  相似文献   

Assessing the efficacy of Duddingtonia flagrans chlamydospores per gram of faeces to control Haemonchus contortus larvae     

Nadia Florencia Ojeda-Robertos  Juan Felipe de Jesus Torres-Acosta  Armando Jacinto Aguilar-Caballero  Armín Ayala-Burgos  Ligia Amira Cob-Galera  Carlos Alfredo Sandoval-Castro  Roberto Carlos Barrientos-Medina  Pedro Mendoza de Gives 《Veterinary parasitology》2008

The aims were (a) to quantify the number of Duddingtonia flagrans chlamydospores per gram of faeces (CPG) recovered from sheep administered with different oral doses and, (b) to describe the relationship between CPG and eggs per gram of faeces (EPG) on the efficacy to reduce Haemonchus contortus infective larvae. Three doses of chlamydospores per kg BW were orally administered during seven days: (T1) non treated control group, (T2) 1 × 10⁶, (T3) 2.5 × 10⁶ and (T4) 5 × 10⁶. Three lambs, infected with H. contortus, were used per group. Faeces were obtained from the rectum of each lamb during the fungal administration period (days 0–6) and for six days after that period. Four coproculture replicates were made from each animal in days 2, 4, 6, 8 and 10. A higher chlamydospore dose produced higher CPG in faeces (p < 0.05), but a clear dose dependent effect was not found either in the larvae reduction or in the CPG:EPG ratio. When ratios were re-analyzed, independently of the treatment groups of origin, a better efficacy was obtained with a ratio from 5 to 10 CPG:EPG and a higher ratio (>10 per egg) showed a lower reduction efficacy (p < 0.05). The binomial analysis showed that for each unit of increment in CPG:EPG ratio there was a reduction of larvae number until a point (between 5 and 10 CPG:EPG) where no further reduction was detected. The surface response test indicated that the number of larvae was reduced by CPG until possible saturation. The highest CPG:EPG ratios did not necessarily improve efficacy of D. flagrans.  相似文献   

Intrafollicular treatment with prostaglandins PGE2 and PGF2α inhibits the formation of luteinised unruptured follicles and restores normal ovulation in mares treated with flunixin‐meglumine          下载免费PDF全文

R. Martínez‐Boví  J. Cuervo‐Arango 《Equine veterinary journal》2016,48(2):211-217

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Organizational learning through participatory research: CIP and CARE in Peru     

Oscar Ortiz  Guillermo Frias  Raul Ho  Hector Cisneros  Rebecca Nelson  Renee Castillo  Ricardo Orrego  Willy Pradel  Jesus Alcazar  Mario Bazán 《Agriculture and Human Values》2008,25(3):419-431

Participatory research (PR) has been analyzed and documented from different points of view, with emphasis on the benefits generated for farmers. The effect of PR on organizational learning has, however, received little attention. This paper analyzes the interaction between a research and a development institution, the International Potato Center (CIP) and CARE in Peru, respectively, and makes the case that PR can contribute to creating a collaborative learning environment among organizations. The paper describes the evolution of the inter-institutional collaborative environment between the two institutions for more than a decade, including an information-transfer period (1993–1996), an action-learning period (1997–2002), and a social-learning period (2003–2007). Several lessons learned from each period are described, as are changes in institutional contexts and stakeholders’ perceptions. The case shows that research and development-oriented organizations can interact fruitfully using PR as a mechanism to promote learning, flexibility in interactions, and innovation. Interactions foster the diffusion of information and the sharing of tacit knowledge within and between organizations, which in turn influences behavior. However, the paper also argues that long-term inter-organizational interactions are needed to facilitate learning, which can be used to influence the way organizations implement their interventions in a constantly changing environment.  相似文献   

Sorption-desorption of flucarbazone and propoxycarbazone and their benzenesulfonamide and triazolinone metabolites in two soils     

Koskinen WC  Calderón MJ  Rice PJ  Cornejo J 《Pest management science》2006,62(7):598-602

Sorption-desorption interactions of pesticides with soil determine the availability of pesticides in soil for transport, plant uptake and microbial degradation. These interactions are affected by the physical and chemical properties of the pesticide and soil and, for some pesticides, their residence time in the soil. While sorption-desorption of many herbicides has been characterised, very little work in this area has been done on herbicide metabolites. The objective of this study was to characterise sorption-desorption of two sulfonylaminocarbonyltriazolinone herbicides, flucarbazone and propoxycarbazone, and their benzenesulfonamide and triazolinone metabolites in two soils with different physical and chemical properties. K(f) values for all four chemicals were greater in clay loam soil, which had higher organic carbon and clay contents than loamy sand. K(f-oc) ranged from 29 to 119 for the herbicides and from 42 to 84 for the metabolites. Desorption was hysteretic in every case. Lower desorption in the more sorptive system might indicate that hysteresis can be attributed to irreversible binding of the molecules to soil surfaces. These data show the importance of characterisation of both sorption and desorption of herbicide residues in soil, particularly in the case of prediction of herbicide residue transport. In this case, potential transport of sulfonylaminocarbonyltriazolinone herbicide metabolites would be overpredicted if parent chemical soil sorption values were used to predict transport.  相似文献   

Effluents from Anaerobic Digestion of Organic Wastes: Treatment by Chemical and Electrochemical Processes     

Annabel Fernandes  Tatiana Jesus  Rodrigo Silva  Maria José Pacheco  Lurdes Ciríaco  Ana Lopes 《Water, air, and soil pollution》2017,228(11):441

The treatment of effluent from anaerobic digestion of organic wastes was carried out using chemical and electrochemical processes, namely, chemical coagulation (CC) with lime, electrocoagulation (EC) with iron consumable electrodes, and electrochemical oxidation (EO) with a boron-doped diamond anode, at different experimental conditions. In the CC assays, the highest chemical oxygen demand (COD) removal, 50%, was achieved for a lime concentration of 70 g L^?1 after 2 h experiment. Under the experimental conditions studied, EC promoted COD removals of 80% after 5 h and EO led to COD removals of 43% after 6 h electrolysis, being this last removal increased to 60% when chloride was added to the effluent. A combined EC+EO treatment was also performed, utilizing the most favorable experimental conditions obtained in the individual processes, and global removals of 95% in COD and 44% in ammonia nitrogen were attained after 5 h of EC followed by 6 h of EO. These results proved that the combined process can be an efficient alternative in the treatment of effluents from anaerobic digestion of organic wastes with the characteristics of the studied effluent.  相似文献   

Multiparameter Quantitative Optimization in the Synthesis of a Novel Coagulant Derived from Tannin Extracts for Water Treatment     

Jesus Beltrán-Heredia  Jesus Sánchez-Martín  Leticia Martín-García 《Water, air, and soil pollution》2012,223(5):2277-2286

A novel tannin-based coagulant has been synthesized at lab scale. A multiparameter optimization was performed on the production process, and up to five variables were studied according to the response surface methodology in a face-centered design of experiments which included two temperatures, two pH levels, and the reaction time in the chemical process. The coagulant involved diethanolamine, formaldehyde, and a tannin extract from Acacia mearnsii de Wild. The results revealed an average optimum combination for dye and surfactant removal which was able to remove either Alizarin Violet 3R and sodium dodecylbenzene sulfonate efficiently from water effluents.  相似文献   

Multiclass method for the determination of pesticides in stem of coconut palm using matrix solid-phase dispersion prior to liquid chromatography analysis     

Jemmyson Romário de Jesus  Sandro Navickiene 《Wood Science and Technology》2014,48(6):1317-1326

A method was developed using matrix solid-phase dispersion and liquid chromatography with ultraviolet diode array detection for the determination of bromopropylate, clofentezine, coumaphos, difenoxuron, diniconazole, fenvalerate, flumetralin, fluometuron, and teflubenzuron in the stem of coconut palm. The parameters evaluated included the type of sorbent (C₁₈-bonded silica, neutral alumina, silica gel, and Florisil) and the volume of the eluting solvent, acetonitrile. The best results were obtained using 0.25 g of stem, 1.0 g of neutral alumina as sorbent, and 5 mL of acetonitrile. The method was validated using stem samples spiked with pesticides at different concentration levels (0.01–10.0 µg mL^?1). Average recoveries (using three replicates) ranged from 70 to 91 %, with relative standard deviations between 1.6 and 10 %. Detection and quantification limits were in the ranges 0.01–0.05 and 0.05–0.2 µg g^?1, respectively.  相似文献   

Variable selection, outlier detection, and figures of merit estimation in a partial least-squares regression multivariate calibration model. A case study for the determination of quality parameters in the alcohol industry by near-infrared spectroscopy     

Valderrama P  Braga JW  Poppi RJ 《Journal of agricultural and food chemistry》2007,55(21):8331-8338

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Land cover monitoring by fractal analysis of digital images     

Jaime Velázquez-García  Jesus Arcadio Muñoz-Villalobos  Mario Martínez Menes  Gabor Korvin 《Geoderma》2010,160(1):83-2

Quantitative information about the land cover is a fundamental issue for any soil management practice. The use of high-resolution remote sensing for this purpose is still questionable because of some poorly measurable or unknown parameters involved in the interaction between the electromagnetic waves and the soil surface. The recorded heterogeneous, highly variable and multi-temporal numerical databases require new analytical tools for signal's pattern recognition and space/time interpretation. In this research we use a novel and versatile low-cost technique (Fractal Image Informatics) for indirect measurement of the soil cover by in situ digital imagery and fractal interpretation. The roughness of gray level distribution across the images is measured in terms of Hurst exponent (H) computed at the global (“firmagram”) and local (“reference lines”) scales and correlated with some direct physical measurements of the residues' weight and the degree of surface covering. The comparative analysis of six contrasting tillage systems was carried out on Mollic Andosol of Michoacan State, Mexico. The results show that H extracted from the soil surface images reveals the differences in land cover in a statistically significant manner. The image roughness, and therefore its Hurst exponent, had a negative correlation with the total weight of plant residues (R² = 0.80) as well as with the degree of soil covering (R² = 0.92). Strong positive correlation (R² = 0.86) was observed between the local H (extracted from the reference lines of the image) and global H (determined from the firmagram), confirming the scale invariance of the studied Andosol and the fractal nature of its digital images. All results are in qualitative and quantitative agreement with the in situ visualized patterns of residue distribution across the experimental plots. We conclude that Fractal Image Informatics is a precise and low-cost technique suitable to monitor the land cover in real time/space by digital imaging.  相似文献