Analysis of Synergistic and Antagonistic Effects of Herbicides Using Nonlinear Mixed-Model Methodology

2004 ◽  
Vol 18 (2) ◽  
pp. 464-472 ◽  
Author(s):  
David C. Blouin ◽  
Eric P. Webster ◽  
Wei Zhang
Keyword(s):  
Repeated Measures ◽  
Mixed Model ◽  
Block Design ◽  
Nonlinear Function ◽  
Nonlinear Mixed Model ◽  
Antagonistic Effects ◽  
Randomized Block Design ◽  
Using Data ◽  
Mixed Model Methodology ◽  
Proc Nlmixed

When herbicides are applied in mixture, and infestation by weeds is less than expected compared with when herbicides are applied alone, a synergistic effect is said to exist. The inverse response is described as being antagonistic. However, if the expected response is defined as a multiplicative, nonlinear function of the means for the herbicides when applied alone, then standard linear model methodology for tests of hypotheses does not apply directly. Consequently, nonlinear mixed-model methodology was explored using the nonlinear mixed-model procedure (PROC NLMIXED) of SAS System®. Generality of the methodology is illustrated using data from a randomized block design with repeated measures in time. Nonlinear mixed-model estimates and tests of synergistic and antagonistic effects were more sensitive in detecting significance, and PROC NLMIXED was a versatile tool for implementation.

scholarly journals PSIV-10 Preference evaluation of plant functional types grasses in calves

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 225-226
Author(s):  
María A Vulliez ◽  
María Bruni ◽  
Ana I Trujillo ◽  
Martín Durante ◽  
Lucrecia Lezana ◽  
...  
Keyword(s):  
Repeated Measures ◽  
Fixed Effects ◽  
Mixed Model ◽  
Block Design ◽  
Neutral Detergent Fiber ◽  
Functional Types ◽  
Randomized Block Design ◽  
Functional Types Of Plants ◽  
Group B ◽  
Cut Leaves

Abstract The functional types of plants (PFT) ecological approach could be used to link the preferences of ruminants. In order to investigate if ruminant preferences were associated with this approach, three PFT groups were evaluated. A group “B”, represented by Paspalum urvillei (PU-B), “C” by Nassella neesiana (NN-C) and Sporobolus indicus (SI-C) and “D” by Andropogon lateralis (AL-D). In a randomized block design with repeated measures over time, two independent cafeteria trials (autumn-winter, A-W, and spring-summer, S-S) were carried out in calves (n = 8 for A-W; n = 4 for S-S; BW=240–270 kg) arranged in four pens. In three sessions of ten minutes each, calves received 120–160 gDM of fresh cut leaves from the different species. Dry matter intake (DMI), nitrogen intake (NI) and neutral detergent fiber intake (NDFI) were measured. Data were analyzed with a mixed model that included specie and session as fixed effects and blocks as a random. The statistical analyses were performed with SAS (University Edition), data is expressed as lsmeans and was considered to differ when Tukey test presented P < 0.05. No significant differences were observed between sessions. The DMI and NI were higher in NN-C and lower in AL-D (P < 0.01) during A-W. However, in S-S, higher DMI and NI were observed in AL-D and SI-C while NN-C presented the lower DMI and NI (P < 0.01). The FDNI did not show differences in A-W meanwhile in S-S was positively associated with DMI (Table1). Interestingly, when the season changed, it was observed a change in PFT preference, in A-W calves preferred NN-C whereas in S-S preferred AL-D. However, attributes associated with preferences were maintained in both stations, for instance, higher DMI was associated with higher NI. Additional research is required on the interactions between PFT approach and the preference of animals for different species.

scholarly journals Genetic parameters and simultaneous selection for root yield, adaptability and stability of cassava genotypes

2013 ◽  
Vol 48 (12) ◽  
pp. 1562-1568 ◽  
Author(s):  
João Tomé de Farias Neto ◽  
Elisa Ferreira Moura ◽  
Marcos Deon Vilela de Resende ◽  
Pedro Celestino Filho ◽  
Sebastião Geraldo Augusto
Keyword(s):  
Genetic Parameters ◽  
Mixed Model ◽  
Block Design ◽  
Genotypic Variation ◽  
Root Yield ◽  
Growing Seasons ◽  
Randomized Block Design ◽  
Simultaneous Selection ◽  
Selection For ◽  
Mixed Model Methodology

The objective of this work was to estimate genetic parameters and to evaluate simultaneous selection for root yield and for adaptability and stability of cassava genotypes. The effects of genotypes were assumed as fixed and random, and the mixed model methodology (REML/Blup) was used to estimate genetic parameters and the harmonic mean of the relative performance of genotypic values (HMRPGV), for simultaneous selection purposes. Ten genotypes were analyzed in a complete randomized block design, with four replicates. The experiment was carried out in the municipalities of Altamira, Santarém, and Santa Luzia do Pará in the state of Pará, Brazil, in the growing seasons of 2009/2010, 2010/2011, and 2011/2012. Roots were harvested 12 months after planting, in all tested locations. Root yield had low coefficients of genotypic variation (4.25%) and broad-sense heritability of individual plots (0.0424), which resulted in low genetic gain. Due to the low genotypic correlation (0.15), genotype classification as to root yield varied according to the environment. Genotypes CPATU 060, CPATU 229, and CPATU 404 stood out as to their yield, adaptability, and stability.

scholarly journals Genetic parameters and estimated genetic gains in young rubber tree progenies

2013 ◽  
Vol 48 (4) ◽  
pp. 411-416 ◽  
Author(s):  
Cecília Khusala Verardi ◽  
Erivaldo José Scaloppi Junior ◽  
Guilherme Augusto Peres Silva ◽  
Lígia Regina Lima Gouvêa ◽  
Paulo de Souza Gonçalves
Keyword(s):  
Genetic Gain ◽  
Genetic Parameters ◽  
Block Design ◽  
Rubber Tree ◽  
First Year ◽  
Genetic Gains ◽  
Selection Gain ◽  
Randomized Block Design ◽  
Using Data ◽  
Selection Of

The objective of this work was to assess the genetic parameters and to estimate genetic gains in young rubber tree progenies. The experiments were carried out during three years, in a randomized block design, with six replicates and ten plants per plot, in three representative Hevea crop regions of the state of São Paulo, Brazil. Twenty-two progenies were evaluated, from three to five years old, for rubber yield and annual girth growth. Genetic gain was estimated with the multi-effect index (MEI). Selection by progenies means provided greater estimated genetic gain than selection based on individuals, since heritability values of progeny means were greater than the ones of individual heritability, for both evaluated variables, in all the assessment years. The selection of the three best progenies for rubber yield provided a selection gain of 1.28 g per plant. The genetic gains estimated with MEI using data from early assessments (from 3 to 5-year-old) were generally high for annual girth growth and rubber yield. The high genetic gains for annual girth growth in the first year of assessment indicate that progenies can be selected at the beginning of the breeding program. Population effective size was consistent with the three progenies selected, showing that they were not related and that the population genetic variability is ensured. Early selection with the genetic gains estimated by MEI can be made on rubber tree progenies.

scholarly journals PSIV-3 Effect of winter-feeding system and roughage level in feedlot ration on subsequent spring grazing behavior and dry matter intake of beef growing heifers

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 228-229
Author(s):  
María Victoria Burjel ◽  
Alvaro Simeone ◽  
Oscar Bentancur ◽  
Natalia Zabalveytia ◽  
Virginia Beretta
Keyword(s):  
Repeated Measures ◽  
Dry Matter ◽  
Block Design ◽  
Ingestive Behavior ◽  
Dry Matter Intake ◽  
Feeding System ◽  
Grazing Behavior ◽  
Randomized Block Design ◽  
Winter Feeding

Abstract This study aimed to evaluate the effect of winter-feeding system (grazing, GFS vs. feedlot, FFS) and ration roughage level (RL), on subsequent spring grazing behavior and forage dry matter intake (DMI). Thirty-two Hereford female calves (149 ± 13 kg) were assigned to four winter dietary treatments (110 days) in a randomized block design (n = 2/treatment): three feedlot rations differing RL (Setaria italica) (0%, 35% or 70% DM) or oats grazing (5 kg DM/100 kg LW). In spring (84 days) all treatments grazed a mixed grass-legume pastures (4317 ± 1009 kg DM/ha; 6 kg DM/100 kg LW). During weeks 1, 3 and 5 after changing diets, diurnal behavior activity (effective/search grazing, rumination, idling or water intake) was visually recorded and DMI estimated from the in vivo DM digestibility (DMD) and fecal production. Data were analyzed according to a block design with repeated measures, with general model including block, treatment (T), week (W) and T×W effects. Means were compared through orthogonal contrasts (Table 1). Spring DMI varied with T (P = 0.0084) regardless of W effect (P = 0.1619), with higher values for GFS compared to FFS (1.55 vs. 1.16 kg/100 kg LW, P = 0.0034) and for 70RL compared to 35RL (P = 0.0286). DMD did not differ between treatments (P = 0.2488) but was lower on W1 than W5 (55 vs. 64 %, P = 0.0150). T×W was significant (P < 0.0001) for effective grazing, rumination and idling. On W1, heifers from GFS grazed less (0.40 vs. 0.49, P = 0.0268) but tended to ruminate more (0.26 vs. 0.18, P = 0.0591) than FFS. As pasture DMD improved (W5) GFS grazed more (0.64 vs. 0.51, P = 0.0020) but ruminated less (0.14 vs. 0.21, P = 0.0450) than FFS. Transition from FFS to spring grazing might reduce pasture DMI modifying animal ingestive behavior compare to animals from GFS. Impact could be higher when ration RL is below 70%.

scholarly journals Comparison of growth curves of two genotypes of dairy goats using nonlinear mixed models

2013 ◽  
Vol 152 (5) ◽  
pp. 829-842 ◽  
Author(s):  
J. G. L. REGADAS FILHO ◽  
L. O. TEDESCHI ◽  
M. T. RODRIGUES ◽  
L. F. BRITO ◽  
T. S. OLIVEIRA
Keyword(s):  
Random Effects ◽  
Growth Curve ◽  
Mixed Model ◽  
Growth Curves ◽  
Growth Patterns ◽  
Dairy Goat ◽  
Residual Variance ◽  
Nonlinear Mixed Model ◽  
Error Structure ◽  
Mixed Model Methodology

SUMMARYThe objective of the current study was to assess the use of nonlinear mixed model methodology to fit the growth curves (weightv.time) of two dairy goat genotypes (Alpine, +A and Saanen, +S). The nonlinear functions evaluated included Brody, Von Bertalanffy, Richards, Logistic and Gompertz. The growth curve adjustment was performed using two steps. First, random effectsu1,u2andu3were linked to the asymptotic body weight (β1), constant of integration (β2) and rate constant of growth (β3) parameters, respectively. In addition to a traditional fixed-effects model, four combinations of models were evaluated using random variables: all parameters associated with random effects (u1,u2andu3), onlyβ1andβ2(u1andu2), onlyβ1andβ3(u1andu3) and onlyβ1(u1). Second, the fit of the best adjusted model was refined by using the power variance and modelling the error structure. Residual variance ($\sigma _e^2 $) and the Akaike information criterion were used to evaluate the models. After the best fitting model was chosen, the genotype curve parameters were compared. The residual variance was reduced in all scenarios for which random effects were considered. The Richards (u1andu3) function had the best fit to the data. This model was reparameterized using two isotropic error structures for unequally spaced data, and the structure known in the literature as SP(MATERN) proved to be a better fit. The growth curve parameters differed between the two genotypes, with the exception of the constant that determines the proportion of the final size at which the inflection point occurs (β4). The nonlinear mixed model methodology is an efficient tool for evaluating growth curve features, and it is advisable to assign biologically significant parameters with random effects. Moreover, evaluating error structure modelling is recommended to account for possible correlated errors that may be present even when using random effects. Different Richard growth curve parameters should be used for the predominantly Alpine and Saanen genotypes because there are differences in their growth patterns.

scholarly journals PSVI-19 Evaluating the addition of an alpha-amylase enzyme to two bulk-flake density weights of corn fed to beef finishing steers

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 219-220
Author(s):  
Caleb Lockard ◽  
Cathy Lockard ◽  
Wyatt Smith ◽  
Brian Campbell ◽  
Jenny Jennings
Keyword(s):  
Fixed Effects ◽  
Mixed Model ◽  
Block Design ◽  
Carcass Characteristics ◽  
Feedlot Cattle ◽  
Alpha Amylase ◽  
Beef Steers ◽  
Finishing Cattle ◽  
Subsequent Performance ◽  
Randomized Block Design

Abstract An alpha-amylase enzyme has the potential to increase starch digestibility, thus improving feedlot cattle performance and efficiency. The objective of this experiment was to evaluate the addition of an alpha-amylase enzyme on two steam-flaked bulk densities and subsequent performance of finishing beef steers. Forty-eight crossbred steers (325 ± 19 kg), were used in a complete randomized block design with a 2 × 2 factorial treatment design. Factors were corn processing and enzyme addition. Dietary treatments were steam-flaked corn-based diets with two bulk-flake density weights of corn (0.32 kg/L vs. 0.39 kg/L). Experimental treatments were 1) 0.32 kg/L with no enzyme (32NE), 2) 0.39 kg/L with no enzyme (39NE), 3) 0.32 kg/L with enzyme (32E), and 4) 0.39 kg/L with enzyme (39E) on a DM basis. The enzyme was applied at 0.50 kg/T of steam-flaked corn (As-fed basis). Data were analyzed using a mixed model with fixed effects of flake weight, enzyme, and flake weight × enzyme interaction. Throughout the feeding period, starch availability for 0.32 kg/L and 0.39 kg/L corn averaged 60.7% and 42.2%, respectively. Steers receiving the alpha-amylase enzyme had no differences in BW (P ≥ 0.62), ADG (P ≥ 0.55), and DMI (P ≥ 0.56) compared to NE steers. Furthermore, carcass characteristics did not differ (P ≥ 0.26) between E and NE steers. Feeding an alpha-amylase enzyme to finishing cattle had no detrimental effects on performance or carcass characteristics. Overall, a more highly processed corn was observed to decrease dry matter intake and increase the potential for digestive upsets. This may limit the use of the alpha-amylase enzyme to a lesser processed corn.

scholarly journals A Noninvasive Method for Assessing Oocyte Competency

2020 ◽  
pp. 1-5
Author(s):  
Cara Wessels Wells ◽  
Cara Wessels Wells ◽  
L. Penrose ◽  
M. Orth ◽  
S. Prien
Keyword(s):  
Ethylene Glycol ◽  
Membrane Permeability ◽  
Repeated Measures ◽  
Block Design ◽  
Membrane Integrity ◽  
Oocyte Cryopreservation ◽  
Vitro Fertilization ◽  
Randomized Block Design ◽  
Pre Treatment

There is an increasing demand to evaluate oocyte competency and viability for oocyte cryopreservation and use for in vitro fertilization. Oocytes suffer decreased survival of cryopreservation as compared to embryos, due to physical characteristics of the oocyte. The objective of this study is to determine if a specific gravity device (SGD) can estimate oocyte viability based on oocyte descent through the buoyancy system. All experiments were performed in a research laboratory with a randomized block design with repeated measures. Three hundred-seventy-six oocytes were collected from seven mice and randomly assigned to one of four treatments: exposure to 60C for 30 min, acidified media for 1h, ethylene glycol-glycerol cryoprotectant for 1h, or standard culture to serve as control. To further analyze the relationship between oocyte descent time and viability, 98 additional oocytes were passed through SGD before and after treatment. Oocytes were stained with Coomassie Blue to determine membrane permeability and estimate viability based on treatment. Oocytes treated with 60C heat, acidified media and ethylene glycol/ glycerol cryoprotectant solution demonstrated altered descent times from control and pre-treatment oocytes (P<0.05). Oocytes exposed to heat and cryoprotectants descended more rapidly through SGD than control and pre-treatment oocytes (P<0.05). Oocytes treated with acidified media descended more slowly through SGD (P<0.05). Permeation of stain into oocytes exposed to lethal treatments confirmed changes in membrane integrity post-treatment and further indicates SGD can detect such shifts. This suggests SGD can predict competency between live and dead oocytes. In conclusion, SGD can detect shifts in oocyte density due to altered membrane permeability, which can suggest information about oocyte competency. This information can help differentiate between high- and low-quality fresh oocytes to help select which oocytes to freeze and result in improved oocyte cryopreservation and fertilization.

scholarly journals Nutritional Status and Productive Components of Maize Fertilized With Sewage Sludge

2018 ◽  
Vol 10 (6) ◽  
pp. 86
Author(s):  
Carlos Cesar Breda ◽  
Renan Francisco Rimoldi Tavanti ◽  
Onã Da Silva Freddi ◽  
Tauan Rimoldi Tavanti ◽  
Aline Regina Piedade ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Grain Yield ◽  
Repeated Measures ◽  
Block Design ◽  
Mineral Fertilizer ◽  
Mineral Fertilizers ◽  
Randomized Block Design ◽  
Productive Potential ◽  
Phosphorus And Potassium ◽  
Maize Fertilization

The response of crops to the application of biofertilizers in the soil is not yet well established. Therefore, we carried out this study with the objective of evaluating the productive potential of maize fertilized with doses of sewage sludge, comparing with the use of mineral fertilizer over four agricultural seasons. The experiment was conducted in a Red Dystroferric Nitosol (Ultisol) in a randomized block design and repeated measures in time. The treatments consisted of five doses of sewage sludge and one treatment using nitrogen, phosphorus and potassium in formulation. All fertilizations were carried out at maize sowing at four planting times (summer and 2nd crop of 1st agricultural year and, summer and 2nd crop of 2nd agricultural year) and replicates. The results showed a cumulative increase in the P, Ca, Mg and Zn leaf concentrations over the four seasons crops, when the sewage sludge was used in the 30 and 40 Mg ha-1 doses. However, reductions in plant height, weight and maize cob diameter, mass and grain yield were observed at the end of the last harvest. The treated sewage sludge is a viable alternative for maize fertilization in the first harvest, provides increases in grain yield in the order of 1.35 Mg ha-1 and can be recommended instead of NPK mineral fertilizers in built-up fertility soils.

scholarly journals Identification of Trichomonas vaginalis in Different Papanicolaou Test Preparations: Trends Over Time in the College of American Pathologists Educational Interlaboratory Comparison Program

2013 ◽  
Vol 137 (8) ◽  
pp. 1043-1046
Author(s):  
Lydia Pleotis Howell ◽  
Teresa M. Darragh ◽  
Rhona J. Souers ◽  
Nicole Thomas ◽  
Ann T. Moriarty
Keyword(s):  
Proficiency Testing ◽  
Repeated Measures ◽  
Trichomonas Vaginalis ◽  
Mixed Model ◽  
Interlaboratory Comparison ◽  
Papanicolaou Test ◽  
Nonlinear Mixed Model ◽  
Before And After ◽  
Performance Results ◽  
Over Time

Context.—The College of American Pathologists' Interlaboratory Comparison Program in Gynecologic Cytology has seen an increase in enrollment in liquid-based Papanicolaou test challenges with a decrease for conventional Papanicolaou tests. Trichomonas vaginalis can be difficult to identify in all preparation types. Objectives.—To evaluate 20 years of participant results from the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology for Trichomonas to ascertain whether performance has changed because of the introduction of liquid-based Papanicolaou and proficiency testing. Design.—Concordance rates for the target diagnosis of Trichomonas vaginalis were evaluated for 167 956 participant responses (1990–2010). A nonlinear mixed model was fit with participant type, preparation type, and a 2-level program year (1990–2005 and 2006–2010) reflecting before and after proficiency testing began. A repeated-measures component allowed modeling of the slide-specific performance to ensure that the overall results were not based on the performance of a few slides. Results.—Cytotechnologists had higher concordance with the target diagnosis than did pathologists (89.8% [72 992 of 81 319] versus 83.4% [72 271 of 86 637], P &lt; .001) and better performance for each preparation type (P = .003). Concordance initially dropped after the introduction of proficiency testing (P &lt; .001) for conventional and liquid-based (SurePath) preparations by both participant types, followed by quick, parallel improvement. Conclusions.—Performance is high in the detection of Trichomonas vaginalis in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology. Liquid-based Papanicolaou and proficiency testing minimally affected participant performance. Cytotechnologists performed better over time and across preparation types than did pathologists, although pathologists showed performance results parallel to that of the cytotechnologists. Awareness of the performance differences by pathologists and cytotechnologists, as well as their difference in proficiency among liquid-based techniques, may help ensure accurate results in clinical practice.

scholarly journals 375 The effect of supplemental protein from weaning until first breeding on heifer development and uterine environment characteristics

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 140-140
Author(s):  
Kiernan J Brandt ◽  
Taylor B Ault ◽  
Liesel G Schneider ◽  
Phillip R Myer ◽  
Kyle J McLean
Keyword(s):  
Repeated Measures ◽  
Mixed Model ◽  
Block Design ◽  
Protein Supplementation ◽  
Control Group ◽  
Weight Class ◽  
Uterine Fluid ◽  
Uterine Environment ◽  
Heifer Development ◽  
Supplemental Protein

Abstract Replacement heifer development is one of the most critical components of productive beef operations. By identifying the ideal uterine environment in pre-breeding heifers, fertility and reproductive efficiency can be maximized. Our hypothesis was that different levels of protein supplementation would affect the rate of development and uterine environment of beef heifers. To test the effects of dietary supplementation on these outcomes, a randomized complete block design with repeated measures was implemented. Commercial Angus heifers (n = 60) were blocked by BW into 4 weight classes. Within each weight class, three pens of 5 heifers each were randomly assigned to one of three treatment groups of supplemental protein [10% (control), 20% (P20), and 40% (P40)]. All heifers were allowed access to ad libitum grass hay. Bodyweight and BCS were collected every 2 weeks to monitor heifer development. Uterine fluid samples were collected monthly by flushing with sterile saline to evaluate components of the uterine environment. Relative uterine pH was calculated by subtracting saline pH from the uterine flush pH. Separate mixed model ANOVAs and mean separation via PROC GLIMMIX (SAS 9.4, Cary, NC) were used to determine if protein supplementation treatments, time and their interactions influenced BW, BCS, or uterine environment. Bodyweight of the control group was significantly lower (P &lt; 0.05) than P20 or P40 groups from December to March. There was an interaction between treatment and time for relative uterine pH (P = 0.002). In November, the P40 group exhibited less change in pH compared to the control group (0.33±0.1 vs. 0.74±0.1; P &lt; 0.05). Whereas in December the P40 (0.23±0.1) group showed more basic uterine environment compared to the P20 (-0.22±0.1) or control (-0.13±0.1) groups (P &lt; 0.05). In conclusion, higher protein supplementation does improve heifer growth and development, as well as altering the pH of the uterine fluid from weaning to first breeding

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