Morphological quality of black walnut (Juglans nigra L.) seedlings largely dictates their capacity to establish well in plantations and their performance potential for use as rootstocks in grafting. Larger seedlings and rootstocks, attained from propagation at relatively low nursery sowing densities, have comparatively more expansive root systems for exploitation of soil resources and greater n...

This study describes the effects of different stocking densities on texture/colour characteristics, protein content /amino acid and lipid content/fatty acid composition of rainbow trout fillet. Stocking density was selected 5 (Group A), 15 (Group B), 25 (Group C) kg fish m−3. Tukey’s Multiple Comparison Test showed insignificant differences between measured size/weight measurement and condition f...

This study aims to understand the spatial distribution of organic carbon and its sequestration potential in Tunisian soils. Soil organic carbon (SOC) stock was estimated in the 0-30 cm and to 0-100 cm soil depth for Tunisia using maps of soils and of the departments, combined with results from a soil database. The original soil classification was simplified to nine soils. Tunisia contains 24 go...

The conservation of tropical forest carbon stocks offers the opportunity to curb climate change by reducing greenhouse gas emissions from deforestation and simultaneously conserve biodiversity. However, there has been considerable debate about the extent to which carbon stock conservation will provide benefits to biodiversity in part because whether forests that contain high carbon density in t...

The aim of this paper is to discuss the validity of the results of Wada and Jacobson (Can. J. Fish. Aquat. Sci. 55, 1998) and to propose a new concept of the stock-recruitment relationship for the Japanese sardine. Two regression analyses were used: simple regression and Deming regression. Reproductive success was defined as recruitment (R) divided by egg production. A false decreasing trend wa...

Estimating the amount of variation due to spatial dependence at different scales provides a basis for designing effective experiments. Accurate knowledge of spatial structures is needed to inform silvicultural guidelines and management decisions for long term sustainability of forests. Furthermore, geostatistics is a useful tool to describe and draw map the spatial variability and estimation o...

Effects of low-density broiler breeder diets on offspring performance and mortality were studied using 2,100 female and 210 male Cobb 500 breeders. Breeder treatments involved 4 experimental groups and a control group with normal density diets (ND, 2,600 kcal of AME/kg during rearing and 2,800 kcal of AME/kg during laying). In treatment 2, nutrient densities were decreased by 12% (LD12) and 11%...

This paper studies the optimal control of an animal-vegetation system where growth in the animal stock is density independent. The ecological system is shown to have a limit cycle, under certain parameter values, but can also be stabilized by a simple harvesting rule. The managing unit maximizes profits from selling the meat, over an infinite planning horizon. With a domestic animal stock, cost...

Understanding how combinations of fishing effort and selectivity affect productivity is central to fisheries research. We investigate the roles of fishing regulation in comparison with ecosystem status for Baltic Sea cod stock productivity, growth performance, and population stability. This case study is interesting because three cod populations with different exploitation patterns and stock st...

The nature and intensity of intraspecific competition can vary greatly among taxa, yet similarities in these interactions can lead to similar population dynamics among related organisms. Variation along the spectrum of intraspecific competition, with contest and scramble competition as endpoints, leads to vastly different responses to population density. Here we investigated the diversity of in...