De Lima R.A.F.,University of Sao Paulo |
Batista J.L.F.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
Prado P.I.,University of Sao Paulo
Forest Science | Year: 2015
In forestry, the description of tree sizes is commonly performed by fitting statistical models to diameter distributions. However, there is little agreement on which models are more flexible to this end, especially in tropical forests. Here we provide the simultaneous evaluation at species and subplot levels of 10 models using large data sets from four representative forest types in Brazil. We aimed to detect which models provide best fits and under which sample properties (size, median, variance, skewness, and kurtosis). We show that the combination of the logit-logistic, odd Weibull, Weibull, and Johnson’s special bounded models provided reasonable descriptions for nearly all species (94.8%) and subplots (99.6%). However, there was little overlap between these four models, meaning that single models were rarely appropriate to describe the majority of cases. This complementarity was evident between the odd Weibull (better performance for more symmetrical, bimodal, or rotated-sigmoid patterns) and logit-logistic models (typical right-skewed and heavy-tailed patterns). The performance of all models was significantly related to forest type or sample properties. Models with more than three parameters had more problems related to optimization convergence, confidence interval estimation, and unrealistic fits. Finally, we discuss some theoretical issues related to the choice of appropriate models. © 2015 Society of American Foresters.
Priolli R.H.G.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
Wysmierski P.T.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
da Cunha C.P.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
Pinheiro J.B.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
Vello N.A.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo
Genetics and Molecular Biology | Year: 2013
Soybean is one of the most valuable and profitable oil crop species and a thorough knowledge of the genetic struc-ture of this crop is necessary for developing the best breeding strategies. In this study, a representative collection of soybean cultivars recommended for farming in all Brazilian regions was genotyped using 27 simple sequence repeat (SSR) loci. A total of 130 alleles were detected, with an average allelic number of 4.81 per locus. These alleles deter-mined the core set that best represented this soybean germplasm. The Bayesian analysis revealed the presence of two clusters or subgroups within the whole collection (435 soybean cultivars) and the core set (31 entries). Cultivars of similar origin (ancestral) were clustered into the same groups in both analyses. The genetic diversity parameters, based on the SSR loci, revealed high similarity between the whole collection and core set. Differences between the two clusters detected in the core set were attributed more to the frequency of their ancestors than to their genetic base. In terms of ancestry, divergent groups were presented and a panel is shown which may foster efficient breed-ing programs and aid soybean breeders in planning reliable crossings in the development of new varieties. © 2013, Sociedade Brasileira de Genética.
Bicudo A.J.A.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
Sado R.Y.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo |
Cyrino J.E.P.,Escola Superior Of Agricultura Luiz Of Queirozuniversidade Of Sao Paulo
Aquaculture Nutrition | Year: 2010
Improper dietary protein and energy levels and their ratio will lead to increased fish production cost. This work evaluated effects of dietary protein: energy ratio on growth and body composition of pacu, Piaractus mesopotamicus. Fingerling pacu (15.5 ± 0.4 g) were fed twice a day for 10 weeks until apparent satiation with diets containing 220, 260, 300, 340 or 380 g kg-1 crude protein (CP) and 10.9, 11.7, 12.6, 13.4 or 14.2 MJ kg-1 digestible energy (DE) in a totally randomized experimental design, 5 × 5 factorial scheme (n = 3). Weight gain, specific growth rate increased and feed conversion ratio (FCR) decreased significantly (P < 0.05) when CP increased from 220 to 271, 268 and 281 g kg-1 respectively. Pacu was able to adjust feed consumption in a wide range of dietary DE concentration. Fish fed 260 CP diets showed best (P < 0.05) protein efficiency ratio and FCR with 11.7-12.6 MJ kg-1; but for the 380 CP-diets group, significant differences were observed only at 14.2 MJ kg-1 dietary energy level, suggesting that pacu favours protein as energy source. DE was the chief influence on whole body chemical composition. Minimum dietary protein requirement of pacu is 270 g kg-1, with an optimum CP: DE of 22.2 g MJ-1. © 2009 Blackwell Publishing Ltd.