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Beras merupakan makanan pokok di Indonesia. Beberapa varietas padi gogo unggul baru telah dilepas dan perlu dilengkapi pemupukan yang akurat di lokasi tertentu. Salah satu jenis pupuk tersebut adalah nitrogen (N). Penelitian ini bertujuan untuk mengetahui efisiensi penggunaan N pada padi gogo IPB 9G sebagai respon terhadap dosis pupuk N. Dosis pupuk yang diaplikasikan adalah 0, 46, 92, 138, dan 184 kg N ha-1 dalam bentuk urea (46% N). Percobaan dilakukan menggunakan rancangan acak kelompok dengan 3 ulangan di Darmaga, Bogor pada Maret-Juli 2018. Petak percobaan berukuran 3.5 m x 3.0 m. Padi gogo ditanam dengan jarak 50 cm x 10 cm. Efisiensi penggunaan N dinilai dari pertumbuhan padi, serapan N, efisiensi agronomi dan fisiologis. Peningkatan tinggi tanaman dan jumlah anakan mengikuti peningkatan dosis N. Serapan N dan hasil gabah memiliki respon kuadratik terhadap dosis N dan dapat menjadi indikator efisiensi pemupukan N. Serapan N dan hasil gabah yang maksimum diperoleh dari dosis pupuk N yang hampir sama, rata-rata 143.8 kg N ha-1 (312.5 kg urea ha-1). Untuk efisiensi pemupukan N padi gogo IPB 9G pada tanah dengan N total sedang (0.27%) di musim kering dapat diaplikasikan 143.8 kg N ha-1 (urea 312.5 kg N ha-1). Kata kunci: efisiensi agronomis, efisiensi fisiologis, hasil biji, serapan N

In pharmaceutical industry, statistically valid experimental design can be utilized to optimize data in order to provide an economic and effective formulation, which could overcome several product and process development problems. Domperidone is a BCS Class II drug and has wide range of use, but has very poor bioavailability when administered orally because of degradation in intestinal fluid. The present study was focused on formulation, evaluation and optimization of mucoadhesive tablets of domperidone using a four-factor, three-level Box-Behnken design (BBD) so as to retain the prepared optimized formulation in gastric fluid for a prolong period of time in order to have better bioavailability and to get a sustained action. Physicochemical properties of the prepared formulations were determined according to the USP pharmacopeia official method and found satisfactory, except friability which was optimized to get the acceptable value. In-vitro dissolution study was performed for 8 hours for all the prepared formulations using USP II (paddle type) dissolution tester having 0.1N HCl (pH 1.2) as dissolution medium. Obtained data was further analyzed by means of quadratic response surface models so as to find out an optimize formulation in terms of desirable condition of dissolution rate after 1 hour, after 8 hours, total mucoadhesion time and tablet friability. Optimized formulation was further evaluated and it was found that, it was almost similar to the proposed optimized data. The formulation can provide a high degree of patient compliance, as sustained release formulation reduces the side effects and the cost of the formulation will be minimal as lesser amount of effort will be needed employing statistical model instead of conventional trial and error method. Dhaka Univ. J. Pharm. Sci. 19(1): 65-76, 2020 (June)

A study was conducted to determine the standardized total tract digestible phosphorus (STTD P) requirement for 24- to 130-kg finishing pigs housed under commercial conditions. A total of 1,130 barrows and gilts (PIC 359 × 1050, Hendersonville, TN; initially 24.2 kg) were used, with 26 to 27 pigs per pen with 7 replicates per treatment. Pens of pigs were allotted to treatments in a randomized complete block design with body weight (BW) as the blocking factor. The dietary treatments were fed in 4 phases and were formulated to contain 80%, 90%, 100%, 115%, 130%, and 150% of the National Research Council (NRC) requirement estimate for finishing pigs within each phase. Weight ranges for each phase were: 27 to 49, 49 to 76, 76 to 90, and 90 to 130 kg. Treatments were achieved by increasing the amount of monocalcium phosphate at the expense of corn in the diet with no added phytase. All diets were formulated to contain a similar 1.14:1 to 1.16:1 total Ca:P ratio across treatments in all phases. Increasing STTD P resulted in a quadratic response (P < 0.05) in average daily gain (ADG), gain-to-feed ratio (G:F), and final BW. The greatest improvement was observed with STTD P at 130% of NRC for ADG and final BW and at 115% STTD P for G:F. Average daily feed intake increased linearly (linear, P < 0.05) with the inclusion of STTD P. Increasing STTD P resulted in an increase (quadratic, P < 0.05) in hot carcass weight (HCW) and carcass ADG with the greatest response observed with STTD P at 130% of NRC. There was a marginally significant response (quadratic, P < 0.10) in carcass G:F, with the greatest improvement with STTD P at 115% of NRC. Carcass yield decreased (linear, P < 0.05) with increasing STTD P, while there was a marginally significant (linear, P < 0.10) decrease in backfat and increase in fat-free lean. At the end of the study, a metacarpal was collected and analyzed for bone ash. Increasing STTD P resulted in an increase (linear, P < 0.05) in bone ash weight and percentage ash. For ADG and G:F, the quadratic model demonstrated the best fit. The maximum response in ADG and G:F was estimated at 122% and 116% of NRC STTD P, respectively. The broken-line linear model best fit the data for percentage bone ash, with a plateau achieved at 131% of the NRC STTD P. In conclusion, the estimated STTD P requirement of 24 to 130 kg ranged from 116% to 131% of the NRC publication (2012) requirement estimate.

This study aimed to compare three methods of estimating the optimum plot size to evaluate the fresh matter productivity of pearl millet (Pennisetum glaucum L.), slender leaf rattlebox (Crotalaria ochroleuca), and showy rattlebox (Crotalaria spectabilis). Twenty-seven uniformity trials were carried out with pearl millet, slender leaf rattlebox, and showy rattlebox cultivated alone and intercropped. Fresh matter productivity was evaluated in 972 basic experimental units (BEU) of 1 m × 1 m (36 BEU per trial). The optimum plot size was determined using the methods modified maximum curvature, linear response with plateau model, and quadratic response with plateau model. The optimum plot size differs between methods and decreases in the following order: quadratic response with plateau model (9.94 m2), linear response with plateau model (7.41 m2), and modified maximum curvature (3.49 m2). The optimum plot size to evaluate the fresh matter productivity of pearl millet, slender leaf rattlebox, and showy rattlebox cultivated alone or intercropped is 7.41 m2. This size could be used as a reference for future experiments. O objetivo deste trabalho foi comparar três métodos de estimação do tamanho ótimo de parcela para avaliar a produtividade de matéria fresca de milheto (Pennisetum glaucum L.), crotalária ochroleuca (Crotalaria ochroleuca) e crotalária spectabilis (Crotalaria spectabilis). Foram conduzidos 27 ensaios de uniformidade com milheto, crotalária ochroleuca e crotalária spectabilis, em cultivo solteiro e em consórcio. Foi avaliada a produtividade de matéria fresca em 972 unidades experimentais básicas (UEB) de 1 m × 1 m (36 UEB por ensaio). Foi determinado o tamanho ótimo de parcela por meio dos métodos da curvatura máxima modificado, do modelo linear de resposta com platô e do modelo quadrático de resposta com platô. O tamanho ótimo de parcela difere entre os métodos e decresce na seguinte ordem: modelo quadrático de resposta com platô (9,94 m2), modelo linear de resposta com platô (7,41 m2) e curvatura máxima modificado (3,49 m2). O tamanho ótimo de parcela para avaliar a produtividade de matéria fresca de milheto, crotalária ochroleuca e crotalária spectabilis, em cultivo solteiro ou em consórcio é de 7,41 m2. Esse tamanho pode ser utilizado como referência para futuros experimentos. &nbsp

Background Two experiments were conducted to determine the effects of increasing amounts of soybean meal (SBM) in swine diets and estimate the energy value of SBM. Methods A total of 2233 pigs (PIC 337 × 1050, Hendersonville, TN) and 3796 pigs (PIC 359 × C40), initially 11.0 kg and 17.6 kg body weight (BW), were used in Exp. 1 and 2, respectively. In Exp. 1, pigs were placed in 92 pens each containing 20 to 27 pigs. In Exp. 2, pigs were placed in 84 pens each containing 37 to 43 pigs. Treatments were assigned in a randomized complete block design with BW as the blocking factor. Dietary treatments consisted of 21%, 27%, 33%, or 39% SBM in Exp. 1 and 17.5%, 22%, 26.5%, 31%, 35.5%, or 40% SBM in Exp. 2, obtained by changing the inclusion rate of feed-grade amino acids and corn grain. For Exp. 1, representative samples of corn grain, SBM, and distillers dried grains with solubles were analyzed for total AA content prior to diet formulation. For Exp. 2, diets were formulated using NRC (2012) nutrient loadings. Treatment diets were fed for 21 and 22 d (Exp. 1 and 2) and there were 23 replicates in Exp. 1 and 14 replicates in Exp. 2. Pigs were weighed and feed disappearance measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI), gain-to-feed ratio (G:F), and caloric efficiency (CE). Data were analyzed with block as a random effect and treatment as a fixed effect, and contrasts were constructed to test the linear and quadratic effects of increasing SBM. Results In Exp. 1, there was a tendency (linear, P = 0.092) for a decrease in ADFI as SBM increased. There was a tendency (P = 0.090) for a quadratic response for ADG, with a decrease in ADG observed with 39% SBM inclusion. Pigs fed diets with increasing SBM had a tendency (quadratic, P = 0.069) for an increase in G:F up to 33% SBM and an improvement (linear, P = 0.001; quadratic, P = 0.063) in CE with increasing SBM. Using CE to estimate the energy of SBM relative to corn, a value of 105.4% of corn energy or 2816 kcal/kg NE was determined using all data points. When removing the CE value of the 39% SBM treatment due to the quadratic tendency, SBM was estimated to have 121.1% of corn energy or 3236 kcal/kg NE. In Exp. 2, there was a decrease (linear, P = 0.001) in ADFI. Pigs fed increasing SBM had a tendency (linear, P = 0.065) for reduced ADG but an improvement (linear, P = 0.001) in G:F and CE as SBM increased. The energy value of SBM was estimated as 124.7% of corn energy or 3332 kcal/kg NE. Conclusions The results suggest that feeding increasing levels of SBM improves G:F and CE. The energy value of SBM was estimated to be between 105% and 125% of corn, which is much greater than the NRC (2012) would indicate.

An experiment was carried out at farmer’s field of Kushtia district under High Ganges River Floodplain Soil (AEZ-11) during Rabi seasons of 2013-14, 2014-15 and 2015-16. The objectives of the study were to evaluate the effect of boron on the yield of hybrid maize (cv. BARI Hybrid Bhutta-9) and to find out the optimum dose of boron for higher yield and economic return. There were 6 treatments comprising 6 levels (0, 0.5, 1.0, 1.5, 2.0 and 2.5 kg B ha -1 ) of boron along with a blanket dose of N 256 P 65 K 45 S 27 Zn 3 kg ha -1 and cowdung 5 tha -1 . Boron fertility of the initial soil was in medium level (0.33 μg g -1 ). The experiment was conducted in RCB design with three compact replications. Results of three years study revealed that hybrid maize responded significantly to added boron for the first two years but for the third year the effect was statistically non significant. The highest grain yield was obtained with 2.5 kg B ha -1 , which was marginally significant with boron control but statistically identical to rest of the boron levels. Although, the yield increased linearly up to 2.5 kg ha -1 but the effect was relatively better fitted with quadratic response function (R 2 = 0.943). The mean highest grain yield found to be 8.55 t ha -1 for 2.5 kg B ha -1 against 8.20 t ha -1 from 0.5 kg B ha -1 and 7.84 t ha -1 from boron control. Considering the boron fertilty of soil, response of maize to boron and economic return, the optimum dose of boron may be 0.5 kg ha-1 for the cultivation of hybrid maize for medium level boron fertile soil under AEZ-11 of Kushtia district or alike. Bangladesh J. Agril. Res. 43(2): 281-288, June 2018

Heat treated EN24 steel is turned with uncoated tungsten carbide inserts in dry cutting environment following Taguchi L16 design of experiments (DOE); and influence of machining process parameters on the surface roughness characteristics (i.e. Ra and Rz) is investigated. The multiple responses are optimized simultaneously using Taguchi based grey relational analysis. Analysis of Variance (ANOVA) for grey relational grade reveals that cutting speed is the most significant parameter followed by feed; and the influence of depth of cut is insignificant. Quadratic response surface models are generated for both the responses; and their adequacy is verified.

Two experiments were conducted to determine the standardized total tract digestible phosphorus (STTD P) requirement for 11- to 23-kg nursery pigs fed diets with or without phytase. A total of 1,080 and 2,140 pigs (PIC 359 × Camborough, Hendersonville, TN; initially 11.4 ± 0.29 and 11.1 ± 0.24 kg) were used in Exp. 1 and Exp. 2, respectively. There were 23 to 27 pigs per pen with 6 and 12 replicate pens per treatment in Exp. 1 and Exp. 2, respectively. After weaning, pigs were fed a common pelleted diet with 0.45% STTD P for 7 d, and a common phase 2 meal diet with 0.40% STTD P for 14 d in Exp. 1 and 18 d in Exp. 2. Pens of pigs were then allotted to dietary treatments in a randomized complete block design with body weight (BW) as the blocking factor. In Exp. 1, dietary treatments consisted of 0.26%, 0.30%, 0.33%, 0.38%, 0.43%, 0.48%, and 0.53% STTD P. Treatments were achieved with the inclusion of monocalcium phosphate at the expense of corn. In Exp. 2, diets contained 1,000 phytase units (FYT; Ronozyme Hiphos 2500, DSM Nutritional Products, Inc., Parsippany, NJ) with assumed release value 0.132% STTD P, and treatments consisted of 0.30%, 0.33%, 0.38%, 0.43%, 0.48%, 0.53%, and 0.58% STTD P. These STTD P concentrations included the expected phytase release of 0.132% STTD P. In both experiments, a similar 1.17:1 Ca:P ratio was maintained across treatments. Statistical models included linear model (LM), quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). In Exp. 1, increasing STTD P increased (linear, P < 0.001) ADG, ADFI, G:F, final BW, and grams of STTD P intake per day and per kilogram of gain. There was also a marginal quadratic response for G:F (P < 0.066). In Exp. 2, ADG and G:F increased quadratically (P < 0.05), whereas ADFI increased linearly (P = 0.060) with increasing STTD P. The BLL and QP model provided similar fit to G:F in Exp. 1, estimating the requirement for maximum G:F at 0.34% and 0.42%, respectively. The BLL was the best fitting model for ADG and G:F in Exp. 2, estimating the breakpoint at 0.40% and 0.37% STTD P, respectively. The BLL and BLQ models estimated the breakpoint for ADG as a function of STTD P intake in grams per day at 2.92 and 3.02 g/d, respectively. These data provide empirical evidence that for 11- to 23-kg pigs, the NRC (2012) accurately estimates the STTD P requirement on a g/d basis. As a percentage of the diet, the STTD P requirement for diets without or with 1,000 FYT added phytase ranged from 0.34% to 0.42%.

Published literature elucidating dietary valine (Val) requirements for female broilers is limited and lacks data for the finisher phase. Three experiments (Exp) were conducted to determine the Val requirement for Cobb MX × 500 females during the grower (Exp 1; 14–28 days), finisher (Exp 2; 28–42 days), and withdraw periods (Exp 3; 42–56 days). Two additional Exp were conducted to determine the Val requirement for Cobb MV × 500 male (Exp 4) and female (Exp 5) broilers from 14–35 days. Corn-soybean meal diets were fed in the experimental period of all Exp to create Val dose response titration diets. Dietary titration levels of digestible Val to digestible Lys (Val/Lys) ratios were: 64–82 in Exp 1; 65–83 in Exp 2 and 3; and 57–92 in Exp 4 and 5. Body weight (BW) gain, feed intake, and feed conversion ratio were determined for each experimental period. At the conclusion of Exp 2 through 5, broilers were processed to determine carcass traits. Requirements were determined using regression analysis, considering the requirement to be 95 % of the quadratic response. No significant linear or quadratic responses were determined for Exp 1 through 3. In Exp 4 and 5, significant responses were observed for feed conversion ratio, but not processing yields. The lack of responsiveness in Exp 1 through 3 are likely due to an inadequate reduction in dietary Val to observe female quadratic responses. Valine requirements were determined to be 78 and 77 Val/Lys for males and females, respectively, based on feed conversion responses.

The number of replications is assumed to interfere in the estimates of the path analysis coefficients. Thus, the objective of this work was to determine the sufficient number of replications for the path analysis of traits in maize cultivars. An experiment was conducted with 15 maize cultivars in a complete randomized block design with nine replications, and seven variables were measured. Then, 511 data files (matrices) formed by all combinations of the nine replications were organized, in groups of 1, 2, 3, 4, 5, 6, 7, 8 and 9 replications. In each matrix, containing the averages of 15 cultivars for the seven variables, Pearson's linear correlation coefficients were estimated, the multicollinearity diagnostics and path analysis were performed and dispersion diagrams were constructed. The sufficient number of replications for the path analysis was determined from the parameter estimates of the quadratic response plateau model. With the replications number increases, the accuracy of the path analysis coefficient estimates improves, but the gains in accuracy gradually decrease. Six replications are sufficient to perform the path analysis of agronomic traits of maize cultivars and can be used as a reference for designing future experiments.

We consider the linear and quadratic higher order terms associated to the response of the statistical properties of a dynamical system to suitable small perturbations. These terms are related to the first and second derivative of the stationary measure with respect to the change of some parameters, expressing how the statistical properties of the system varies under the perturbation. We show a general framework in which one can obtain rigorous convergence and formulas for these two terms. The framework is flexible enough to be applied both to deterministic and random systems. We give examples of such an application computing linear and quadratic response for Arnold maps with additive noise and deterministic expanding maps., Comment: 28 pages. Electronic copy of final peer-reviewed manuscript accepted for publication in Chaos

The present study reports statistical optimization of growth conditions of an opportunistic fungal strain Pichia guilliermondii, isolated from the blood of patients suffering from bancroftian filariasis. Seven key determinants, namely, primary inoculums size (%), volume (mL) and pH of media, serum proportion, temperature (°C), incubation time (hr), and agitation speed (rpm) that influence in vitro growth of the pathogen were optimized statistically using response surface methodology (RSM). RSM with seven factors and two-level Box-Behnken design was employed for designing experimental run, prediction of case statistics, suitable exploration of quadratic response surfaces, and constructing a second-order polynomial equation. Analysis of variance (ANOVA) showed that primary inoculums size, volume of culture media, temperature, incubation time, and agitation speed exert most significant influence over fungal growth. The RSM study predicted that optimum fungal growth can be obtained using 10% primary inoculums size in 100 mL culture media with pH 6.0, 6.28% serum, 32.5°C temperature, and 24 hr of incubation, alongside agitation speed at 400 rpm. The desirability of the optimized growth model for P. guilliermondii is 99.123%, which indicated its accuracy and acceptability. Finally, the optimized growth module illustrated in the study could be useful in improving in vitro growth of clinically important P. guilliermondii.

International audience; The study presented here consisted of the calculation of cross relationships between growth performance parameters, body growth composition, and feed characteristics, using data from an experiment reported in 2 previous publications. In the previous experiment, 30 pelleted diets were given to broiler chickens (8/diet) (21 to 35 d) for in vivo measurement and prediction of AMEn and net energy (NE) values of diets, using 3 trials with 10 diets/trial. In the course of NE determination, individual values for growth, feed intake, and deposition of lipid and protein were measured. Average energy deposited as lipid and protein represented 25.4 and 19.1% AME intake, respectively. Using a multiple regression predicting AME intake, the partial efficiencies of AME for energy deposition as lipid and protein were calculated to be 91.6 and 67.3%, respectively, and the daily amount of AME required for maintenance was evaluated at 0.683 MJ/kg BW0.7. The mean diet NE/AMEn ratios were predicted by an equation combining the lipid content of body growth (positive coefficient) and the apparent digestible protein (ADP) to AMEn ratio (ADP/AMEn), with a quadratic expression for the latter variable. This quadratic response expressed a positive asymptotic relationship, with a plateau for ADP/AMEn values above 1.45 [%/(MJ/kg)]. The equations predicting growth always included either the dietary percentage of water-insoluble cell wall or the AMEn value. The other major parameters predicting growth were either the lipid content of body growth or the CP/AMEn ratio. In many cases, quadratic responses were observed in growth prediction equations. Regressions predicting feed efficiency showed only linear responses. Feed efficiency was predicted precisely by multiple linear regressions based only on AMEn and a dietary protein parameter. According to these regressions, 1% CP was equivalent to 0.247 MJ/kg AMEn in terms of feed efficiency. The most efficient regression predicting the individual lipid content of body growth combined the protein efficiency value (negative coefficient), the CP/AMEn ratio (negative coefficient), AMEn (positive coefficient), and the feather content of body growth (positive coefficient).

Spiral concentrator and spiral plant modelling of chromite bearing ore is investigated in this paper. Spiral product stream responses (grade and recovery) were modelled according to variations in feed conditions (grade, density, flow rate) and primary splitter settings. The two modelling approaches constituted a quadratic response surface and an extension (to accommodate feed conditions) on the original Holland-Batt (1990) spline model. Additional validation of the extended Holland-Batt model behaviour was performed via regression on a second data set, based on hematite separation using spiral concentrators (Sadeghi, 2015). The quadratic model showed higher performance values on the training set; however, the extended Holland-Batt model showed better performance on the test data. Finally, both models were compared in terms of spiral concentrator plant modelling ability (based on an industrial spiral concentration plant). Quadratic response surface models were unable to produce acceptable grade-recovery curve simulations. The extended Holland-Batt model proved to be the superior spiral plant simulation model due to its ability to produce valid grade-recovery curves. The extended Holland-Batt spline-based model shows promise as an improvement over RSM for spiral modelling (and spiral plant simulation). The extended Holland-Batt model can provide the same screening, characterization and optimization functionality of RSM models for single-spiral experimental modelling, with the added benefit of simple extension to spiral plant simulation.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Outra Agência The optimum plot size for ‘Gigante’ cactus pear can be estimated by several methods; thus, ultimately aiming for efficiency, simple use and high precision, the objective of this study was to compare methods for estimating plot sizes: modified maximum curvature method, Hatheway’s convenient plot size method, linear and quadratic response plateau models, and comparison of variances method for evaluating phenotypic characteristics in experiments with ‘Gigante’ cactus pear. Plot sizes were estimated by conducting a uniformity trial. Estimated optimum plot sizes varied with the method and vegetative characteristic. The quadratic response plateau regression estimated the largest plot sizes, whereas Hatheway’s method estimated the smallest plot sizes. Comparison of variances method estimated intermediate plot sizes in comparison with the other methods for most measured characteristics. Plots sizes estimated by modified maximum curvature method are more consistent with results reported by studies on ‘Gigante’ cactus pear. 10 basic unit plot sizes estimated by the linear response plateau model can be used with high precision and practical feasibility for growing cactus pear, thereby improving the use of resources. O tamanho ótimo de parcela para palma forrageira ‘Gigante’ pode ser estimado por vários métodos; assim, visando em última análise a eficiência, uso simples e alta precisão, o objetivo deste estudo foi comparar métodos para estimar tamanhos de parcelas: método de curvatura máxima modificada, método de tamanho de parcela conveniente de Hatheway, modelos de platô de resposta linear e quadrática e método de comparação de variâncias para avaliação de características fenotípicas em experimentos com palma forrageira 'Gigante'. Os tamanhos das parcelas foram estimados através da realização de um ensaio de uniformidade. Os tamanhos ótimos estimados de parcela variaram com o método e a característica vegetativa. A regressão de platô de resposta quadrática estimou os maiores tamanhos de parcelas, enquanto o método de Hatheway estimou os menores tamanhos de parcelas. O método de comparação de variâncias estimou tamanhos de parcelas intermediários em comparação com os outros métodos para a maioria das características medidas. Os tamanhos de parcelas estimados pelo método da curvatura máxima modificada são mais consistentes com os resultados relatados por estudos sobre a palma forrageira ‘Gigante’. 10 tamanhos de parcelas de unidades básicas estimados pelo modelo de platô de resposta linear podem ser usados ​​com alta precisão e viabilidade prática para o cultivo de palma forrageira, melhorando assim o uso dos recursos.

Slow release fertilizers have become an alternative for better efficiency in substrate fertilization for seedlings production, however, there are not many studies approaching the use of such fertilizers in the production of native forest species seedlings. This work aimed to evaluate the effect of different doses of a slow release fertilizer (SRF) on the development and quality of the Inga heterophylla seedlings. The experiment was conducted in a vivarium with 50% of shade for a 150-day period. Randomized blocks were the chosen experimental design, constituted of four treatments and four replications, with twenty plants per experimental unit. The treatments were four doses of Osmocote® FLL (0, 4.1, 8.2 and 12.3 g dm-3) in NPK 15-09-12 formulation, with evaluated variables being the height of the seedling (H), collar diameter (CD), number of leaf pairs (NLP), leaf area (LA), aerial part dry mass (APDM), root dry mass, total dry mass (TDM) and Dickson quality index (DQI). All the evaluated parameters responded significantly to the SRF doses and fit the positive quadratic polynomial model. For all of the analyzed variables, results show that the best averages were obtained by using the doses between 5.7 and 6.5 g dm-3, but due to the quadratic response they presented a decrease in the mean values after doses which were superior to the maximum performance point of each characteristic.

Field studies were conducted in 2011 and 2012 at the Horticultural Crops Research Station near Clinton, NC, to determine ‘Covington' sweetpotato tolerance to S-metolachlor rate and application timing. Treatments were a factorial arrangement of four S-metolachlor rates (0, 1.1, 2.2, or 3.4 kg ai ha−1) and six application timings (0, 2, 5, 7, 9, or 14 d after transplanting [DAP]). Immediately following application, 1.9 cm of irrigation was applied to individual plots. Sweetpotato injury was minimal for all treatments (≤ 10%). No. 1 grade sweetpotato yield displayed a negative linear response to S-metolachlor rate, and decreased from 25,110 to 20,100 kg ha−1 as S-metolachlor rate increased from 0 to 3.4 kg ha−1. Conversely, no. 1 sweetpotato yield displayed a positive linear response to S-metolachlor application timing and increased from 19,670 to 27,090 kg ha−1 as timing progressed from 0 to 14 DAP. Total marketable sweetpotato yield displayed a quadratic response to both S-metolachlor application rate and timing. Total marketable yield decreased from 44,950 to 30,690 kg ha−1 as S-metolachlor rate increased from 0 to 3.4 kg ha−1. Total marketable yield increased from 37,800 to 45,780 kg ha−1 as application timing was delayed from 0 to 14 DAP. At 1.1 kg ha−1S-metolachlor, sweetpotato storage root length to width ratio displayed a quadratic relationship to application timing and increased from 1.87 to 2.23 for applications made 0 to 14 DAP. At 2.2 kg ha−1 of S-metolachlor, sweetpotato length to width ratio displayed a quadratic response to application timing, increased from 1.57 to 2.09 for 0 to 10 DAP, and decreased slightly from 2.09 to 2.03 for 10 to 14 DAP. Application timing did not influence length to width ratio of sweetpotato storage roots for those plots treated with S-metolachlor at either 0 or 3.4 kg ha−1.

1. Research focused on lower light intensity levels is required to set minimum standards appropriate for production and welfare of intensively housed broilers. The objective of this research was to study light intensity (0.1 to 10 lx) effects on Ross × Ross 308 and 708 genotypes. 2. Three experiments (35 d each) using 18 720 broilers were conducted with the initial experiment using two replicates of 0.1, 1, 5 and 10 lx. The second and third experiments examined 0.5, 1, 5 and 10 lx with treatments replicated twice in each experiment in a randomised complete block design with experiment acting as a block. In each experiment, mixed sex broilers from each genotype were housed in 6 equally sized pens per room. 3. In Experiment 1, the introduction of 0.1 lx at d 7 caused high levels of mortality and poor growth rate from d 7 to 14 and was discontinued. 4. In Experiments 2 and 3, increasing light intensity increased body weight gain (0-35 d) and feed intake (0-35 d) in a quadratic and linear fashion, respectively. Similarly, mortality corrected gain to feed ratio (FCR, 0-35 d) demonstrated a quadratic response with a maximum at 5 lx. Carcass, breast meat and skin, abdominal fat and drum skin, as a percentage of live weight, increased while drum bone and wing yield decreased in a linear fashion with increasing light intensity. Total carcass composition was unaffected by light intensity. 5. Genotype effects were numerous. No interactions were found between genotype and light intensity. 6. Ocular dimensions and the incidence of foot pad lesions decreased in a quadratic and linear fashion, respectively, with increasing light intensity. In contrast, welfare-associated gait score and mortality levels were not affected by light intensity. 7. It was concluded that performance, breast meat yield and bird welfare improved with increasing light intensity. The data support 5 lx as a minimum light intensity in broiler production.

A method for characterization of butter cookie quality by assessing the surface browning and water content using multispectral images is presented. Based on evaluations of the browning of butter cookies, cookies were manually divided into groups. From this categorization, reference values were calculated for a statistical prediction model correlating multispectral images with a browning score. The browning score is calculated as a function of oven temperature and baking time. It is presented as a quadratic response surface. The investigated process window was the intervals 4–16 min and 160–200°C in a forced convection electrically heated oven. In addition to the browning score, a model for predicting the average water content based on the same images is presented. This shows how multispectral images of butter cookies may be used for the assessment of different quality parameters. Statistical analysis showed that the most significant wavelengths for browning predictions were in the interval 400–700 nm and the wavelengths significant for water prediction were primarily located in the near-infrared spectrum. The water prediction model was found to correctly estimate the average water content with an absolute error of 0.22%. From the images it was also possible to follow the browning and drying propagation from the cookie edge toward the center.

Mediante un modelo general de respuesta cuadrático se generan recomendaciones sobre dosis óptimas económicas de nitrógeno (N) y fósforo (P) en maíz en dos dominios de recomendación en la Provincia de Chiriquí, Panamá. Para el dominio de recomendación 1 (DR1), caracterizado por alto contenido inicial de P en el suelo y bajos niveles de materia orgánica (MO), las dosis óptimas fueron de 184 kg N/ha y la no aplicación de P. Para el dominio de recomendación 2 (DR2), caraterizado por bajo contenido inicial de P y altos niveles de MO, las dósis óptimas fueron de 72 kg N/ha y 51 kg P2O5/ha. La rentabilidad de la inversión en fertilizantes en el DRl fuesignificativamente superior que aquella alcanzada en el DR2. Para que la fertilización fuera rentable, la tasa m ínima de retorno aceptable debe ser como máximo de 42% para los agricultores en el DR1 y de 93% para aquellos pertenecientes al DR2.

An experiment was conducted to determine dietary energy (ME) and CP requirements of quail chicks using response surface methodology. A total of 40 floor pens of 20 birds each were assigned to 9 diets of central composite design (CCD) containing 5 levels of ME (2,809 to 3,091 kcal/kg) and CP (19 to 24.8% of diet) from 7 to 14 d of age. The experimental results of CCD were fitted with quadratic response models, and ridge analysis was used to compute the optimal response for BW gain (BWG) and feed conversion ratio (FCR). Regression analysis showed that the linear effect of independent variables was significant on bird responses. The quadratic and cross-product effects did not have significant effects on performance. Dietary levels of CP linearly affected BWG and FCR, but the effect of dietary ME was not significant. The ridge maximum analysis on BWG and minimum analysis on FCR models revealed that the maximum BWG may be achieved with 2,950 kcal of ME/kg and 25% CP; and minimum FCR may be obtained with 2,878 kcal of ME/kg and 24.4% CP. The results of this study showed that response surface analysis with the CCD platform was successfully used to optimize dietary requirements of Japanese quail and this methodology could be used for other nutrients.

Studies of drug combinations have become increasingly important, especially in treating malignant cancers. Researchers are interested in identifying compounds that act synergistically when combined. Such synergy is usually measured through an interaction index. The existing statistical methods, in general, estimate the interaction index using pooled data from compounds administered individually and in combination. In this article, we propose a two-stage response surface approach. Parameters of monotherapy dose–response curves are estimated and then incorporated in estimating the interaction index through a quadratic response surface model. Using multiple simulation studies, we demonstrate that the new method gives less biased estimates for both monotherapy dose–response curves and interaction index. Also developed is a bootstrapping method that allows constructing a confidence interval for interaction index at any combination dose levels. An example is provided to illustrate the method.

Observation of leaf spectral profile (color) enables suitable management measures to be taken for crop production. An optical scanner was used: 1) to obtain an equation to determine the greenness of plant leaves and 2) to examine the power to discriminate among plants grown under different nutritional conditions. Sweet basil seedlings grown on vermiculite were supplemented with one-fifth-strength Hoagland solutions containing 0, 0.2, 1, 5, 20, and 50 mM NH4+. The 5 mM treatment resulted in the greatest leaf and shoot weights, indicating a quadratic growth response pattern to the NH4+ gradient. An equation involving b*, black and green to describe the greenness of leaves was provided by the spectral profiling of a color scale for rice leaves as the standard. The color scale values for the basil leaves subjected to 0.2 and 1 mM NH4+ treatments were 1.00 and 1.12, respectively. The other treatments resulted in significantly greater values of 2.25 to 2.42, again indicating a quadratic response pattern. Based on the spectral data set consisting of variables of red-green-blue and other color models and color scale values, in discriminant analysis, 81% of the plants were correctly classified into the six NH4+ treatment groups. Combining the spectral data set with the growth data set consisting of leaf and shoot weights, 92% of the plant samples were correctly classified whereas, using the growth data set, only 53% of plants were correctly classified. Therefore, the optical scanning of leaves and the use of spectral profiles helped plant diagnosis when biomass measurements were not effective. A observação do perfil espectral da folha (cor) permite medidas de gestão adequadas a serem consideradas na produção. Um scanner óptico foi usado para: 1) obter uma equação para determinar o verde das folhas e 2) examinar o poder de discriminar entre as plantas cultivadas sob diferentes condições nutricionais. Mudas de manjericão cultivadas em vermiculita foram suplementadas com solucão de Hoagland contendo um quinto de força e suplementado com 0, 0,2, 1, 5, 20 e 50 mM NH4+. O tratamento de 5 mM resultou em maior peso de folha e parte aérea, indicando um padrão de resposta quadrática para o gradiente de NH4+. Uma equação envolvendo b* , preto e verde para descrever o verde das folhas foi fornecido pelo perfil espectral de uma escala de cores para folha de arroz como padrão. Os valores de cor de escala para as folhas de manjericão submetidos aos tratamentos NH4+ contendo 0,2 e 1 mM foram 1,00 e 1,12, respectivamente. Os outros tratamentos resultaram em valores significativamente superiores, de 2,25 a 2,42 indicando novamente um padrão de resposta quadrática. Com base no conjunto dos dados espectrais constituído por variáveis de cores vermelho-verde-azul e outros modelos de cores e valores da escala de cores, na análise discriminante, 81% das plantas foram corretamente classificadas em a seis NH4+ grupos da planta. Combinando os dados espectrais com os dados de crescimento composto pelo peso das folhas e parte aérea, 92% das amostras de plantas foram corretamente classificadas, enquanto que usando somente o conjunto de dados de crescimento, apenas 53% das plantas foram corretamente classificadas. Neste contexto, a digitalização óptica das folhas e do uso de perfis espectrais auxiliou no diagnóstico da planta, quando as medidas da biomassa não foram efitivas.

A fim de obter confiabilidade nas estimativas, geradas por meio da análise de trilha, é importante definir o número necessário de experimentos. O objetivo deste trabalho foi determinar o número de experimentos necessários para a análise de trilha do número de vagens por planta, do número de sementes por vagem e da massa de cem grãos sobre a produtividade de grãos de cultivares de feijão (Phaseolus vulgaris L.). Treze cultivares de feijão foram avaliadas em nove experimentos conduzidos em Santa Maria, Estado do Rio Grande do Sul, entre os anos agrícolas de 2000/2001 e 2004/2005. Foram mensurados os caracteres produtividade de grãos, número de vagens por planta, número de sementes por vagem e massa de cem grãos. Foram planejadas 511 matrizes de dados (13 cultivares e 4 caracteres) e realizadas análises de correlação, de diagnóstico de multicolinearidade e de trilha, além de construir diagramas de dispersão. O número de experimentos, necessários para a análise de trilha, foi determinado a partir das estimativas dos parâmetros do modelo quadrático de resposta com platô. Na região da depressão central do Estado do Rio Grande do Sul, sete experimentos são suficientes para a análise de trilha em feijão. In order to obtain reliable estimates, generated through path analysis, it is important to define the necessary number of experiments. The objective of this work was to determine the number of experiments necessary for the path analysis the number of pods per plant, number seed per pod and weight of 100 grains on grain yield the common bean cultivars (Phaseolus vulgaris L.). Thirteen common bean cultivars were evaluated in nine experiments conducted in Santa Maria, in Rio Grande do Sul State, Brazil, in the growing seasons between 2000/2001 and 2004/2005. We measured the characters grain yield, number of pods per plant, number seed per pod and weight of 100 grains. Were planned 511 data matrices (13 cultivars and four characters). Analyses of correlation, diagnoses of multicollinearity, path analysis and scatter plots were carried out. The number of experiments necessary for the path analysis, was determined by the estimates of the parameters of the quadratic response plateau model. In the central depression region of Rio Grande do Sul State, Brazil, seven experiments are sufficient for the path analysis in common bean.

Whole field peas were fed at 0, 10, 20, and 30% of DM to 139 yearling steers (British cross; 409 ± 31 kg of initial BW) for a 119-d finishing period. Carcass data and Choice grade strip loins (n = 98) were collected from a commercial abattoir in Lexington, Nebraska. Consumer sensory and Warner-Bratzler shear force analyses were performed on 2.5-cm strip steaks. No differences (P ≥ 0.17) were observed in final BW, ADG, DMI, and G:F of steers. Likewise, no differences (P ≥ 0.23) were observed for HCW, LM area, fat thickness at the 12th rib, yield grade, and marbling scores. However, KPH responded quadratically to increasing dietary amount of field peas (P = 0.02). Regarding the sensorial analysis, feeding peas linearly increased subjective tenderness (P < 0.01) and led to a quadratic response of overall like ratings (P = 0.01) and flavor like ratings (P = 0.12). Feeding peas did not alter (P ≥ 0.64) juiciness, but decreased shear force values linearly when quantities were increased (P = 0.02). These data suggest that feeding peas does not affect steer performance or carcass characteristics differently from dry-rolled corn, but does improve objective and subjective tenderness, overall desirability, and flavor of beef. Field peas could be fed to cattle and give positive attributes to the quality of the meat up to 30% inclusion in the diet.

In response surface analysis, a second order polynomial model is often used for inference on the stationary point of the response function. The standard confidence regions for the stationary point are due to Box & Hunter (1954). The authors propose an alternative parametrization, in which the stationary point is the parameter of interest; likelihood techniques and Bayesian analysis are then easier to perform. The authors also suggest an approximate method to get highest posterior density regions for the maximum point (not simply for the stationary point). Furthermore, they study the coverage probabilities of these Bayesian regions through simulations. Approches vraisemblantiste et bayesienne pour I'inference portant sur le point stationnaire d'une surface de reponse quadratique Resume: Dans l'analyse des surfaces de reponse, un polynǒme du second degre est souvent utilise pour l'inference portant sur le point stationnaire de la fonction de reponse. Les regions de confiance standards pour le point stationnaire sont dues a Box & Hunter (1954). Les auteurs proposent une parametrisation differente dans laquelle le point stationnaire est le parametre d'interět; ceci facilite l'emploi des techniques de vraisemblance et l'analyse bayesienne. Les auteurs suggerent aussi une facon d'approximer les regions de plus haute densite a posteriori pour le point maximum (et non seulement pour le point stationnaire). De plus, ils etudient les proprietes de couverture des regions bayesiennespar voie de simulation.

Para determinar la influencia de la edad al corte en la composicion quimica del ensilado de maiz blanco, se sembraron 36 parcelas (cuatro surcos; 8 m) con el hibrido de maiz blanco Asgrow-7573. En un diseno en bloques completos (DBCA) al azar con cuatro repeticiones, fueron asignadas a nueve fechas de corte: 103, 107, 111, 115, 119, 123, 127, 131 y 135 dias a partir de la siembra. La planta se corto 12 cm del suelo y fue picada a 3 cm; se prepararon mini-silos (5 kg) en bolsa de plastico y se les extrajo el aire. Los silos se abrieron despues de 45 dias y se les determino materia seca, cenizas, proteina cruda, FDN, FDA y pH. A los resultados se les aplico ANDEVA para un DBCA y analisis por polinomios. La materia seca del forraje verde y del ensilado, asi como el pH aumentaron de manera lineal ( P < 0.00001) a como se incremento la edad al corte. La proteina cruda fue mayor ( P < 0.05) en las primeras fechas. FDN y FDA mostraron un comportamiento cuadratico ( P < 0.00001). Se concluye que el corte entre los dias 123 y 127 favorece la composicion quimica del ensilado de maiz blanco. ABSTRACT To determine the influence of cutting age on the chemical composition of white corn silage, 36 plots were planted (four rows; 8 m) with the white corn hybrid Asgrow-7573. In completely randomized block design, with four replications assigned to nine cutting ages: 103, 107, 111, 115, 119, 123, 127, 131, and 135 days from seeding date. Plants were cut 12 cm over ground, and chopped to 3 cm size; mini-silages (5 kg) were prepared in plastic bags, and the air was extracted. The silages were open after 45 days, and dry matter, ashes, crude protein NDF, ADF and pH were determined. Results were analyzed by ANOVA for a completely randomized block design and polynomial analyses were performed. The dry matter (from fresh forage and silage) as pH (P < 0.00001) when cutting age increased. Crude protein was higher (P < 0.05) during early cutting ages. NDF and ADF showed a quadratic response (P < 0.00001). It is concluded that cutting age from 123 to 127 days improves chemical composition of white corn silage.

SUMMARYCrop yield and optimum nitrogen fertilization rates (Nopt) are often calculated ex post by specific functions of the nitrogen fertilization rate, but in doing this, uncertainties in terms of model choice, annual nitrogen response variations and parameter estimation are neglected. In the present study, Nopt, grain yields, net revenues and N balances were estimated for the three crops of an oilseed rape (OSR)–winter wheat–winter barley rotation. The effects of uncertainties were considered using three different statistical models, estimating an identical Nopt over the years and carrying out Monte-Carlo simulations where model parameters were varied according to their estimated standard errors. The statistical models used were the quadratic (Q) polynomial function, the linear response and plateau (LRP) function and the quadratic response and plateau (QRP) function.The Q model tended to estimate the highest Nopt values for the three crops, followed by the QRP and the LRP model in an initial ex post analysis. The highest corresponding mean net revenues in the rotation were estimated by the LRP model, followed by the Q and QRP model; mean N balances increased in the order LRP, QRP and Q. In the comparison of the crops, OSR showed the highest N balances followed by wheat and barley. Considering the protein concentration in wheat, Nopt values estimated by the Q model were considerably higher than without the economic effects of grain quality.In order to consider uncertainties in annual nitrogen response, an ex ante Nopt over the years was determined by maximizing the cumulated net revenues over all years in the rotation. Ex ante Nopt was higher as the mean of the ex post Nopt values for the QRP and LRP model. Average grain yields and net revenues were lower, N balances were higher. Running the Monte-Carlo simulations, ex post Nopt was obtained by 10 000 generated functions in each year and ex ante Nopt by 50 000 generated functions of years 1996, 1997, 1998, 1999 and 2002. This led to an increase in Nopt especially for the LRP model, while effects on the estimation of Nopt by the Q model were rather small. For the LRP model, corresponding mean net revenue decreased and mean N balance rose. In contrast, due to marginal changes in Nopt, the consideration of uncertainties in the estimations had only a small effect on net revenue and N balance in the Q model.In general, all kinds of uncertainty tended to increase Nopt but this effect was much higher for the LRP model as compared to the Q model. This increase in Nopt was associated with decreasing net revenues and increasing N balances. Exceptionally in OSR using the Q model, however, the ex ante approaches considering uncertainty led to slightly lower Nopt values compared to the ex post value.

Combinations of two vegetative N application schemes (single pre-flood [SPF]) and two-way split [2WS]) and five top-dress (TD) N timings (internode elongation [IE], IE+7, 14, 21, and 28 d) were tested for 'Cocodrie' and 'Wells' rice. When averaged across TD timings, the average grain yield for Cocodrie was 9142 kg ha -1 when the SPF scheme was used, compared with 8736 kg ha -1 for the 2WS scheme. Whole and total milled rice percentage showed a quadratic response to TD timing and was greatest when the TD application was made at IE+28 d for Cocodrie; however, only the early vegetative N application scheme affected the net return, which, when averaged across TD timings, was $75 ha -1 greater when the SPF scheme was used. When N was top-dressed at the IE timing, whole milled rice was 52.9% with the SPF scheme, compared with 49.8% with the 2WS scheme. In addition, where the SPF scheme was used, whole milled rice responded quadratically to TD timing compared with linearly when the 2WS scheme was used. Sensitivity analyses indicated that at three N prices ($0.16, $0.33, and $0.48 kg -1 ), the relative difference in net returns among treatment combinations were not changed. Rice grain yields for semi-dwarf cultivars respond more favorably to a higher percentage of the total N being applied pre-flood. Growers should implement N fertilizer practices that produce the highest economic grain yield, which for Cocodrie is to use the SPF vegetative N application scheme regardless of the TD N timing.

In this article we develop the asymptotic distribution for the eigenvalues of a quadratic response surface by using the result of Eaton and Tyler to extend the results of Carter, Chinchilli, and Campbell and Bisgaard and Ankenman to the case including nondistinct eigenvalues. In particular, we suggest a method for estimating the confidence regions for multiple roots.

Com o objetivo de determinar a densidade populacional e espaçamento entre fileiras ideais para milho no Oeste Catarinense, foram conduzidos dois experimentos (um com híbrido de ciclo precoce e outro com híbrido de ciclo normal) nos anos agrícolas 1995/96, 1996/1997 e 1997/98, em Chapecó. O delineamento experimental foi blocos casualizados arranjados em parcelas subdivididas, com a parcela principal composta de quatro espaçamentos entre fileiras (70, 85, 100 e 115cm) e a sub-parcela de quatro densidades populacionais (30000, 50000, 70000 e 90000 plantas ha-1). Os híbridos responderam de forma quadrática ao aumento da população de plantas, apresentando máxima eficiência técnica ao redor de 74000 plantas ha-1. As populações de 50000, 70000 e 90000 plantas ha-1, de ambos os híbridos, tiveram produtividade de grãos semelhantes entre si e superiores a 30000 plantas ha-1. O híbrido de ciclo precoce foi mais produtivo a 70 e 85cm do que a 115cm, enquanto o híbrido de ciclo normal não teve diferença entre os espaçamentos. O aumento da população de plantas reduziu significativamente o peso de mil grãos, o número de grãos/espiga e o número de espigas/planta. To determine the ideal plant population and row spacing for corn, two trials were carried out (one with earlier hybrid and other with normal cycle hybrid) during the growing seasons of 1995/96, 1996/97 and 1997/98, in Chapecó, in the West of Santa Catarina, Brazil. The experimental design of both trials was complete randomized blocks arranged in split-plots, with main plot composed of four row spacings (70, 85, 100 and 115cm) and subplot composed of four stands (30000, 50000, 70000 and 90000 plants ha-1). Both hybrids had quadratic response to the increase in plant population with maximum technical efficiency around 74000 plants ha-1. Populations of 50000, 70000 and 90000 plants ha-1 of both hybrids had similar grain yields and superior to 30000 plants ha-1. The earlier hybrid had grain yields at 70 and 85cm superior to 115cm, while normal cycle hybrid did not present differences among spacings. The increase in plant population reduced significantly the weight of one thousand grains, the number of grains per ear and the number of ears per plant.

Use of the right amount of nitrogenous fertilizer is fundamental for farm profitability and environmental protection. For efficient fertilizer use, it is necessary to have information on the optimum rates under different soil‐climatic conditions. Curve fitting techniques are often used to estimate optimal fertilizer rates, but a significant problem exists in selecting a proper model for a particular soil‐cropping situation. The objective of the work reported here was to compare and evaluate the linear and quadratic response models with yield plateau specifications and modified Mitscherlich's equation. The three models gave good fit to the data when evaluated by R2. Even though all three models predicted nearly the same maximum yields, the fertilization recommendations estimated by linear response plateau (LRP) and quadratic response plateau (QRP) models were considerably lower than that given by modified Mitscherlich's equation and also the systematic bias with Mitscherlich's model was higher. It is sugge...

Made available in DSpace on 2015-02-02T12:39:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-07-01Bitstream added on 2015-02-02T13:07:52Z : No. of bitstreams: 1 S0103-84782014000701204.pdf: 120544 bytes, checksum: 116b4f5ee2979f0809d29970d733948a (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) O objetivo deste trabalho foi avaliar a influência do número e posição de níveis nutricionais utilizados em ensaios dose-resposta na estimativa do nível-ótimo (OL) e ajuste dos modelos polinomial quadrático (QP), exponencial (EXP), linear response plateau (LRP) e quadratic respose plateau (QRP). Utilizaram-se dados provenientes de ensaios dose-resposta realizados na FCAV-Unesp Jaboticabal, atendendo as pressuposições de homocedasticidade e normalidade. O ajuste dos modelos foi avaliado considerando as seguintes estatísticas: coeficiente de determinação ajustado (R²adj), coeficiente de variação (CV) e soma dos quadrados dos desvios (SSD).Verificou-se que, nos modelos QP e EXP, pequenas mudanças na localização e distribuição dos níveis ocasionam grandes alterações na estimativa do OL. O modelo LRP foi influenciado pela ausência ou presença do nível intermediário às fases de resposta e estabilização (mudança da reta crescente para platô). O modelo QRP precisou de um número maior de níveis na fase de resposta e o último nível da fase de estabilização para estimar corretamente o platô. Pôde-se concluir que a determinação do OL e o ajuste dos modelos dependem da posição e quantidade de níveis, além das características específicas de cada modelo, mas níveis definidos próximos do verdadeiro requerimento e não muito espaçados são melhores para estimar corretamente o OL. The aim of this research was to evaluate the influence of the number and position of nutrient levels used in dose-response trials in the estimation of the optimal-level (OL) and the goodness of fit on the models: quadratic polynomial (QP), exponential (EXP), linear response plateau (LRP) and quadratic response plateau (QRP). It was used data from dose-response trials realized in FCAV-Unesp Jaboticabal considering the homogeneity of variances and normal distribution. The fit of the models were evaluated considered the following statistics: adjusted coefficient of determination (R²adj), coefficient of variation (CV) and the sum of the squares of deviations (SSD).It was verified in QP and EXP models that small changes on the placement and distribution of the levels caused great changes in the estimation of the OL. The LRP model was deeply influenced by the absence or presence of the level between the response and stabilization phases (change in the straight to plateau). The QRP needed more levels on the response phase and the last level on stabilization phase to estimate correctly the plateau. It was concluded that the OL and the adjust of the models are dependent on the positioning and the number of the levels and the specific characteristics of each model, but levels defined near to the true requirement and not so spaced are better to estimate the OL. Universidade Estadual Paulista UNESP Departamento de Ciências Exatas FCAV Universidade Estadual Paulista UNESP Departamento de Ciências Exatas FCAV

We compute linear and quadratic static density response functions of three-dimensional Yukawa liquids by applying an external perturbation potential in molecular dynamics simulations. The response functions are also obtained from the equilibrium fluctuations (static structure factors) in the system via the fluctuation-dissipation theorems. The good agreement of the quadratic response functions, obtained in the two different ways, confirms the quadratic fluctuation-dissipation theorem. We also find that the three-point structure function may be factorizable into two-point structure functions, leading to a cluster representation of the equilibrium triplet correlation function.

In searching for optimum conditions, the response surface methods comprise two phases. In the first phase, the method of the steepest ascent with a 2 k-p design is used in searching for a region of improved response. The curvature of the response surface is checked in the second phase. For testing the evidence of curvature, a reasonable design is a 2 k-p fractional factorial design augmented by centre runs. Using c-optimality criterion, the optimal number of centre runs is investigated. Incorporating c-efficiencies for the curvature test with D-efficiencies and G-efficiencies of CCDs for the quadratic response surfaces and then, adopting the Mini-Max principle, i.e. maximizing the worst efficiency, we propose robust centre runs with respect to the three optimality criteria to be chosen.

A paint manufacturing company was facing the problem of Vehicle Separation and Settling in one of its prime products. These two abnormalities are, in general, opposing in nature. The manufacturer tried several modifications in the existing recipe for the product but failed to control them. Experimentation was carried out using mixture design, a special type of designed experiment, and quadratic response surface models were fitted for both the responses. Finally, optimum formulation was obtained by simultaneously optimizing the two response surface models. During the determination of optimal formulation, different methods were compared. The optimum formulation is currently being used for regular manufacturing.

To study the relationship between the amount of soil mineral nitrogen before sowing of onions (Nmin) and the optimum amount of nitrogen fertilizer (Nopt), 36 multilevel fertilizer nitrogen trials were conducted in the Netherlands between 1978 and 1982. For 26 trials Nopt was within the studied range (0-200 kg N/ha) and could be estimated using a quadratic response function. A significant linear relationship between Nopt and Nmin before sowing was only found when Nmin in the layer 0-30 cm was considered. The same 26 trials were analysed together using a quadratic and a linear exponential response function. However, with both methods the yield predicted from Nmin did not prove to be superior to a fixed nitrogen application rate of about 125 kg of nitrogen/ha. A verification pointed out that the relationship overestimated the opt. amount of fertilizer nitrogen found in 8 independent multilevel fertilizer nitrogen trials. A fixed rate of 100-125 kg of nitrogen/ha yielded better results. The possible reasons for the absence of a strong relationship between the amount of soil mineral nitrogen before sowing and the opt. amount of nitrogen fertilizer are discussed.

Predictive equations to compute the chilling time, mass loss at the end of chilling, temperature history at the geometric center of round and mass loss history during beef carcass chilling were developed using validated computer models and response surface analysis. Central composite rotatable design was used to obtain quadratic response surfaces for various chilling parameters. Temperatures at the geometric center of round muscle were predicted within 95% confidence interval. Mass loss histories were also predicted within 95% confidence interval after 5 h postmortem. Temperature predictions were within ± 2C and mass loss predictions were within ± 1.0%.

This article considers the selection of experimental designs for the estimation of second-order response surface metamodels in a simulation environment. Rather than construct designs based on the premise that the postulated model exactly represents the simulated response, as is the case in optimal design theory, we assume that the estimation process may be biased by the presence of unfitted third-order terms. We therefore seek to specify experimental plans that address the bias due to possible model misspecification as well as traditional variance considerations. The performance measure used for this “fit-protect” scenario is Box and Draper's design criterion of average mean squared error of predicted response. Four important classes of response surface experimental plans are examined: (1) central composite designs, (2) Box-Behnken plans, (3) three-level factorial experiments, and (4) small central composite designs. Each design class is studied in conjunction with three pseudorandom number assignment strategies: (1) the use of a unique set of streams at each design point; (2) the assignment of a common stream set to all experimental points: and (3) the simultaneous use of common and antithetic streams through design blocking. Comparisons of both design classes and assignment strategies are presented to assist the user in the selection of an appropriate experimental strategy.

Polynomial equations, relating the growth rate of Yersinia enterocolitica to temperature (0–25°C) and pH (4.5–6-5) in a liquid medium were constructed for four different acidulants. The logarithm of the time for a 100-fold increase in bacterial numbers could be represented by a quadratic response surface function of pH and temperature. The interactions between pH and temperature on growth rate were found to be additive. Values for a 2 log cycle increase in growth derived from the model were in good agreement with experimental values. Predictions from the quadratic model and from a square root model were compared with experimental values in laboratory media and UHT milk. The mean square error (MSE) for the quadratic response surface model was smaller than that for the square root model in 81% of cases. In UHT milk the square root model increasingly underestimated growth rate, as the temperature decreased and would ‘fail dangerous’ if used for predictive purposes. This indicated that the response surface model is more reliable for predicting the growth of Y. enterocolitica under conditions of sub-optimal temperature and pH.

O objetivo desse experimento foi avaliar o valor bromatológico da pastagem de aveia preta e azevémsubmetida a diferentes alturas de pastejo, obtida pela simulação de pastejo. O experimento foi conduzido naFazenda Experimental da COAMO, Campo Mourão/PR. O delineamento experimental adotado foi de blocosao acaso, com quatro tratamentos e duas repetições. Os tratamentos foram constituídos por diferentesalturas da pastagem: 7 cm de altura; 14 cm de altura; 21 cm de altura e 28 cm de altura. O método deamostragem utilizado foi a simulação manual do pastejo. Os valores médios de proteína bruta foram de23,8%; 21,8%; 20,8% e 20,9% para os tratamentos de 7 cm; 14 cm; 21 cm e 28 cm respectivamente. Aanálise de regressão demonstra que houve resposta quadrática da altura da pastagem sobre os teoresmédios de proteína bruta. Os valores médios de fibra em detergente ácido (FDA) foram de 25,5%; 28,0%;27,2% e 26,0% para os tratamentos de 7 cm; 14 cm; 21 cm e 28 cm respectivamente. E os valores de fibraem detergente neutro (FDN) foram de 58,5%; 62,2%; 59,7% e 60,5% para os tratamentos de 7 cm; 14 cm;21 cm e 28 cm respectivamente. Os valores médios de fibra em detergente ácido (FDA) e fibra emdetergente neutro (FDN) não apresentaram diferença entre as alturas de pastejo. A utilização da pastagemde aveia preta e azevém em menor altura implicou no aumento dos teores de proteína bruta da forragemobtida na simulação de pastejo dos animais.

The present numerical study provides strong evidence that at standard parameters the response of the Lorenz system to small perturbations of the control parameter r is linear. This evidence is obtained not only directly by determining the response in the observable A(x)=z, but also indirectly by validating various implications of the assumption of a linear response, like a quadratic response at twice the perturbation frequency, a vanishing response in A(x)=x, the Kramers-Kronig relations, and relations between different response functions. Since the Lorenz system is nonhyperbolic, the present results indicate that in contrast to a recent speculation the large system limit (thermodynamic limit) need not be invoked to obtain a linear response for chaotic systems of this type.

In this paper, two approaches for computing statistical confidence intervals for reliability estimated using response surface methods (RSM) are presented. In the first method, three limit states are used to obtain the upper, mean and lower probability of failure at the design point of interest. This approach is integrated with popular probabilistic design algorithms like the MeanValue First-Order-Second-Moment (MV-FOSM), Monte Carlo (MC) and Hazofer-Lind-RackwitzFiessler (HLRF) algorithms. In the second approach, a close form solution to predict confidence intervals for reliability obtained using the MV-FOSM approach is proposed. Analytical derivations for both methods are presented and the methods are validated via a representative case study. The proposed methods are applicable to any quadratic response surface approximation obtained using design-of-experiment methods.

If similar compounds have similar activity, rational subset selection becomes superior to random selection in screening for pharmacological lead discovery programs. Traditional approaches to this experimental design problem fall into two classes: (i) a linear or quadratic response function is assumed (ii) some space filling criterion is optimized. The assumptions underlying the first approach are clear but not always defendable; the second approach yields more intuitive designs but lacks a clear theoretical foundation. We model activity in a bioassay as realization of a stochastic process and use the best linear unbiased estimator to construct spatial sampling designs that optimize the integrated mean square prediction error, the maximum mean square prediction error, or the entropy. We argue that our approach constitutes a unifying framework encompassing most proposed techniques as limiting cases and sheds light on their underlying assumptions. In particular, vector quantization is obtained, in dimensions up to eight, in the limiting case of very smooth response surfaces for the integrated mean square error criterion. Closest packing is obtained for very rough surfaces under the integrated mean square error and entropy criteria. We suggest to use either the integrated mean square prediction error or the entropy as optimization criteria rather than approximations thereof and propose a scheme for direct iterative minimization of the integrated mean square prediction error. Finally, we discuss how the quality of chemical descriptors manifests itself and clarify the assumptions underlying the selection of diverse or representative subsets.

Foi avaliada por intermédio da simulação a produtividade e eficiência de sistemas de criação de bovinos de corte no Rio Grande do Sul diferindo na idade das novilhas ao primeiro parto (IP, anos) e na taxa de natalidade (TN): "Sistema Tradicional" (ST) IP=4; "Sistema Melhorado" (SM) IP=3; e o "Sistema Um Ano" (SU) IP=2. Em cada sistema foi avaliado o efeito da TN variando entre 50 e 90%. Foi usado um modelo estático determinístico. A resposta em produtividade e eficiência à redução na IP foi dependente da TN. No SM e SU foi determinada resposta curvilinear a aumentos na TN, atingindo uma produção máxima de 83,9 e 77,9 quilos de bezerro desmamado (BD)/ha com TN de 82,5 e 92,3%, respectivamente. No ST a resposta foi linear, com aumentos de 6,1 kg BD/ha a cada 10% de aumento na TN. O custo energético por quilo BD produzido diminuiu linearmente, na medida em que a TN aumentou. A simulation model was used to evaluate productivity and efficiency of beef cow-calf systems in Rio Grande do Sul State with different heifers first calving age (CA, years) and calving rates (CR): "Traditional System" (TS) CA=4; "Improved System (IS)" CA=3; "One Year System (OYS)" CA=2. In each system it was studied the effect of CR varying from 50 to 90%. A statistic deterministic model was used. The effect of reducing CA on productivity and efficiency was dependent of CR. IS and OYS showed a quadratic response curve, with maximum production of 83,9 and 77,9 kg of weaned calf (WC)/ ha for CR of 82,5 and 92,3%, respectively. TS response was linear, with increments of 6,1 kg WC/ha for each 10% increase in CR. Energetic cost per quilogram of WC was reduced linearly with increments in CR.

Analisou-se oito experimentos realizados em áreas irrigadas do Submédio São Francisco, entre os anos de 1988 e 1993, com o objetivo de relacionar a resposta do tomateiro industrial (Lycopersicon esculentum, Mill) à adubação fosfatada em solos com diferentes teores de fósforo disponível determinado pelos métodos Mehlich-1 ou Bray-1. Nos solos com conteúdo de P disponível igual ou inferior a 2 mg.dm-3, os aumentos em produtividade, provocados pela adubação foram, em média, de 190,8%, enquanto no solo com teor de P de 8 mg.dm-3, o aumento foi de apenas 21,7%. Porém, em solos com teor de P igual ou superior a 14 mg dm-3, não foi verificada resposta do tomateiro à adubação fosfatada. Para os dois experimentos onde foi possível ajustar equações quadráticas, as produtividades máximas econômicas de tomate (56,47 e 69,35 t.ha-1) foram obtidas com os níveis de 143 e 182 kg.ha-1 de P2O5, respectivamente. Results of eight field experiments carried out in irrigated areas of the Submédio São Francisco River Valley, Northeast Brazil, from 1988 to 1993, were statistically analysed to evaluate the response of processing tomato (Lycopersicon esculentum, Mill) to phosphorus fertiliser, in soils with different available phosphorus contents by the methods of Mehlich - 1 or Bray - 1. The analysis showed that in soils where available P content was equal to or lower than 2 mg.dm-3, the mean increment in tomato yield due to P fertilisation was 190.8%, while in soils where the P content was 8 mg/dm³, the increment was only 21.7%. However, in soils with P content equal or higher than 14 mg dm-3, there was no response of the tomato crop to phosphorus fertilisation. In the two experiments where a quadratic response was observed, the maximum economical yields of 56.47 and 69.35 ton. ha-1 of tomatoes were obtained with 143 and 182 kg.ha-1 of P2O5, respectively.

The use of response surface methodology in the analysis of a factorial trial in the development of a combination treatment for hypertension is discussed. The analysis plan and efficacy results are reviewed with special attention to the quadratic response surface methods that were applied. A key issue is how to test to establish the existence of an effective dose combination. This issue also impacts current designs for combination drugs at fixed doses. Several direct approaches using quadratic response surface methods are discussed. Estimating the combination dose that maximizes the minimum gain of combination over each monotherapy seems most promising.