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Quadratic Effect (quadratic + effect)
Selected AbstractsHabitat selection by Ortolan Buntings Emberiza hortulana in post-fire succession in Catalonia: implications for the conservation of farmland populationsIBIS, Issue 4 2009MYLES H. M. MENZ The Ortolan Bunting Emberiza hortulana is a long-distance migrant that has suffered major population declines across much of its European breeding range. While northern populations are bound largely to farmland, Mediterranean populations are largely confined to habitats subject to recurrent wildfires. Habitat selection of the Ortolan Bunting was assessed in a recently burnt area in Catalonia at landscape and habitat scales. A Zero-inflated Poisson procedure was used to model the abundance of birds in relation to landscape and habitat variables. The most parsimonious landscape model predicted the highest abundance on south-facing slopes, with a gradient above 10°. The most parsimonious habitat model showed a positive quadratic effect of bare ground and regenerating oak Quercus spp., with predicted optima for abundance around 20,30% and 20% cover, respectively. There was a clear relationship between predicted abundance of the Ortolan Bunting and post-fire regenerating oak shrubs. South-facing, moderately sloping areas were favoured and bare ground was a key feature of the species' habitat. A matrix combining patches of sparse oak shrubs and patches of bare ground appears to be the optimal breeding habitat in the Mediterranean. The maintenance or provision of similar habitat features, especially patches of bare ground, may prove crucial for the conservation of rapidly declining Ortolan Bunting populations on farmland across temperate Europe. [source] Fat, wheat bran and salt effects on cooking properties of meat patties studied by response surface methodologyINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2010Hasibe Tekin Summary Response surface methodology was used to investigate the main effects and interactions of composition (processing) variables such as fat (10,30%), wheat bran (5,15%) and NaCl (0,2%) on cooking properties of beef patties. In addition, the ridge analysis was conducted to find the values of processing variables that maximise and minimise the cooking parameters (moisture retention, fat retention, reduction in thickness, reduction in diameter, cooking yield, shrinkage and water-holding capacity). It was found that the moisture and fat retention, reduction in thickness and cooking yield values decreased; however, reduction in diameter and shrinkage values increased, respectively, as the amount of fat increased. However, wheat bran addition increased fat retention, moisture retention, cooking yield and water-holding capacity values of the patties. Increasing NaCl levels decreased water-holding capacity value by its quadratic effect and moisture and fat retention value by its interaction effect with wheat bran. [source] RESPONSE SURFACE METHODOLOGY FOR STUDYING THE QUALITY CHARACTERISTICS OF COWPEA (VIGNA UNGUICULATA)-BASED TEMPEHJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2010GEORGE AMPONSAH ANNOR ABSTRACT Response surface methodology was used to optimize the processing conditions in the preparation of cowpea tempeh. The independent factors studied were boiling time (varying from 5 to 30 min), incubation time (varying from 12 to 48 h) and incubation temperatures (varying from 25 to 50C), whereas the dependent factors were protein content, protein solubility, pH, titratable acidity and total color difference (using L, a* and b*). Regression models were generated and adequacy was tested with regression coefficients (R2) and the lack-of-fit tests. Optimum processing conditions were determined by method of superimposition. There was a strong and significant influence (P < 0.01) of the quadratic effect of the incubation time on the protein content of the cowpea tempeh, with similar significance (P < 0.01) noted in protein solubility with increasing boiling time. The optimum processing conditions observed for the preparation of cowpea tempeh were boiling time of about 20 min, incubation time of about 28 h and incubation temperature of about 37C. PRACTICAL APPLICATIONS Response surface methodology (RSM), as a statistical tool, has been effectively used in food process applications. This study embraced the use of RSM in the optimization of the processing conditions involved in the preparation of cowpea tempeh. Superimposition of the contour plots developed from the regression models indicated that cowpea with optimum quality characteristics should be processed at a boiling time of 20 min, incubation time of 28 h and incubation temperature of 37C. These conditions could be adopted for the industrial production of cowpea tempeh. [source] Nutrient digestibility response to graded dietary levels of sodium chloride in weanling pigsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2008Yu-long Yin Abstract BACKGROUND: Sodium (Na+), chloride (Cl,) and phosphorus (Pi) are involved in a number of metabolic and physiological processes in the body, and these mineral elements must be supplied to the animal via the diet. The intention of this study was to evaluate the effect of dietary supplementation with different levels of sodium chloride (0.1, 0.2, 0.3, 0.4, 0.5 and 0.6% NaCl) on apparent and true P digestibility (APD and TPD) and dry matter (DM), crude protein (CP) and calcium (Ca) digestibility in weanling pigs. RESULTS: Dietary NaCl had a quadratic effect on both APD and TPD (P < 0.05) but not on DM, CP and Ca digestibility (P > 0.05). At an NaCl concentration of 0.41% the APD and TPD values were 41.5 and 53.3% respectively. CONCLUSION: These results suggest that a high level of dietary Na+ may enhance P absorption and improve its digestibility by coupling Na+ transportation to Pi absorption via the energy-requiring Na+/Pi co-transporter. Copyright © 2008 Society of Chemical Industry [source] | ||||||||||