RESUMO

Predictive models based on empirical similarity are instrumental in biology and data science, where the premise is to measure the likeness of one observation with others in the same dataset. Biological datasets often encompass data that can be categorized. When using empirical similarity-based predictive models, two strategies for handling categorical covariates exist. The first strategy retains categorical covariates in their original form, applying distance measures and allocating weights to each covariate. In contrast, the second strategy creates binary variables, representing each variable level independently, and computes similarity measures solely through the Euclidean distance. This study performs a sensitivity analysis of these two strategies using computational simulations, and applies the results to a biological context. We use a linear regression model as a reference point, and consider two methods for estimating the model parameters, alongside exponential and fractional inverse similarity functions. The sensitivity is evaluated by determining the coefficient of variation of the parameter estimators across the three models as a measure of relative variability. Our results suggest that the first strategy excels over the second one in effectively dealing with categorical variables, and offers greater parsimony due to the use of fewer parameters.

RESUMO

The growth of Haematococcus pluvialis in two alternative culture media NPK (10:10:10) and ME (macrophyte extract), under mixotrophic conditions using sugarcane molasses as a carbon source were evaluated for 28 days. The molasses was used in two different ways, in a native form (untreated) and a hydrolyzed (pretreated). Cell density of Haematococcus pluvialis in mixotrophic cultivation was higher in pretreated molasses. Growth rate was higher when pretreated molasses were employed in mixotrophic cultivation with NPK culture medium (k=0.5 7th growth day). Biomass, chlorophyll-a, conductivity and total inorganic nitrogen were not significantly different (p>0.05) during the experimental period for two mixotrophic cultivation and culture media. Protein contents of H. pluvialis biomass were higher in NPK culture medium with pretreated molasses (50% dry biomass). Annual biomass production was 520 kg-1 dry biomass with untreated molasses for two culture media, and 650 and 520 kg-1 dry biomass with pretreated molasses for NPK and ME culture media, respectively. The use of NPK and ME culture media in mixotrophic cultivation may be a new protocol for H. pluvialis cultivation due to the low cost and similar annual production.

O crescimento de Haematococcus pluvialis foi avaliado em dois meios de cultura alternativos NPK (10:10:10) e ME (extrato de macrófita), em condições mixotróficas utilizando melaço de cana-de-açúcar como fonte de carbono durante 28 dias. O melaço foi utilizado de duas maneiras diferentes, bruto (não tratado) e hidrolisado (pré-tratado). A densidade celular de Haematococcus pluvialis em cultivo mixotrófico foi maior em melaço pré-tratado. A taxa de crescimento foi maior no cultivo mixotrófico pré-tratado em meio de cultura NPK com k=0,5 (7º dia). Biomassa, clorofila-a, condutividade e nitrogênio inorgânico total não foram significativamente diferentes (p>0,05) durante o período experimental para as duas condições mixotróficas e meios de cultura. Os teores de proteína de H. pluvialis foram maiores no meio de cultura NPK em melaço pré-tratado, acima de 50% da biomassa seca. A produção anual de biomassa foi de 520 kg-1 de biomassa seca em melaço não tratado para os dois meios de cultura e de 650 e 520 kg-1 de biomassa seca em melaço pré-tratado para meios de cultura NPK e ME, respectivamente. O uso de meios de cultura NPK e ME em cultivo mixotrófico pode se tornar um novo protocolo adotado para o cultivo de H. pluvialis devido ao baixo custo e similar produção anual de biomassa.

Assuntos

RESUMO

This study analyzes data on the biology of sperm whales, Physeter macrocephalus Linnaeus, 1758, obtained between 1965 and 1980 by the COPESBRA at the Costinha Whaling Station, Paraíba, Brazil. The data come from the log books of the whaling ships and from the spreadsheets containing biological information filled out by employees of the SUDEPE at the flensing plan of the whaling station. The catches occurred from June to December, in an area delimited by 06º22'-07º52'S and 33º26'-34º58'W. A total of 641 sperm whales were killed in this period. The average sex ratio was 2.05 females to each male. The mean largest frequency of females was recorded in the first and the last months of the season, and that of males in July/August. The mean total length (TL) of males was 11.4 m (minimum 7.2 m, maximum 17.6 m). The females had a mean TL of 10.1 m (minimum 8.6 m, maximum 12.9 m). A decrease was observed in the TL of females along the years. Fetuses were observed in 8.3% of the catches. They had TL between 0.24 and 4.3 m. All sperm whales had food in their stomachs, showing that they feed in the area. As in other places north to the 40ºS, there was a higher frequency of females than males. The difference between the time of maximum catch of males and females may reflect a temporal segregation in the arrival of sperm whales in the area. The reproductive activity of sperm whales in these tropical waters occurs year-round.

RESUMO

This study analyzes data on the biology of sperm whales, Physeter macrocephalus Linnaeus, 1758, obtained between 1965 and 1980 by the COPESBRA at the Costinha Whaling Station, Paraíba, Brazil. The data come from the log books of the whaling ships and from the spreadsheets containing biological information filled out by employees of the SUDEPE at the flensing plan of the whaling station. The catches occurred from June to December, in an area delimited by 06º22'-07º52'S and 33º26'-34º58'W. A total of 641 sperm whales were killed in this period. The average sex ratio was 2.05 females to each male. The mean largest frequency of females was recorded in the first and the last months of the season, and that of males in July/August. The mean total length (TL) of males was 11.4 m (minimum 7.2 m, maximum 17.6 m). The females had a mean TL of 10.1 m (minimum 8.6 m, maximum 12.9 m). A decrease was observed in the TL of females along the years. Fetuses were observed in 8.3% of the catches. They had TL between 0.24 and 4.3 m. All sperm whales had food in their stomachs, showing that they feed in the area. As in other places north to the 40ºS, there was a higher frequency of females than males. The difference between the time of maximum catch of males and females may reflect a temporal segregation in the arrival of sperm whales in the area. The reproductive activity of sperm whales in these tropical waters occurs year-round.

RESUMO

This study analyzes data on the biology of sperm whales, Physeter macrocephalus Linnaeus, 1758, obtained between 1965 and 1980 by the COPESBRA at the Costinha Whaling Station, Paraíba, Brazil. The data come from the log books of the whaling ships and from the spreadsheets containing biological information filled out by employees of the SUDEPE at the flensing plan of the whaling station. The catches occurred from June to December, in an area delimited by 06º22'-07º52'S and 33º26'-34º58'W. A total of 641 sperm whales were killed in this period. The average sex ratio was 2.05 females to each male. The mean largest frequency of females was recorded in the first and the last months of the season, and that of males in July/August. The mean total length (TL) of males was 11.4 m (minimum 7.2 m, maximum 17.6 m). The females had a mean TL of 10.1 m (minimum 8.6 m, maximum 12.9 m). A decrease was observed in the TL of females along the years. Fetuses were observed in 8.3% of the catches. They had TL between 0.24 and 4.3 m. All sperm whales had food in their stomachs, showing that they feed in the area. As in other places north to the 40ºS, there was a higher frequency of females than males. The difference between the time of maximum catch of males and females may reflect a temporal segregation in the arrival of sperm whales in the area. The reproductive activity of sperm whales in these tropical waters occurs year-round.