The assessment of harsh working conditions requires a correct evaluation of the metabolic rate. This paper revises the basis described in the ISO 8996 standard for the evaluation of the metabolic rate at a work station from the recording of the heart rate of a worker during a representative period of time. From a review of the literature, formulas different from those given in the standard are ...

A study was carried out over 2 years (2008/2009 and 2009/2010) in Greece, in order to evaluate the weed control using reduced rates of the herbicide mesosulfuron-methyl+iodosulfuron-methyl-sodium of four major weeds (Avena sterilis, Phalaris minor, Papaver rhoeas and Sinapis arvensis), grain yield and yield components of five wheat cultivars (Bob, Cosmodur, Meridiano, Quadrato and Simeto). The ...

Abscisic acid (ABA) concentrations and growth rates of developing soybean (Glycine max [L.] Merr. cv. Wye) seeds and pod walls were determined from anthesis to maturation using high pressure liquid chromatographic techniques. Developing soybean seeds contain up to 12,200 ng/g fresh weight of ABA compared to 330 ng/g fresh weight for pod walls. In the developing seeds ABA levels correlated with ...

Plant-pollinator interactions are one of the most important and variable mutualisms in nature. Multiple pollinators often visit plants and can vary in visitation rates, pollen removal and deposition, and spatial and temporal distribution, altering plant reproduction and patterns of pollinator-mediated selection. Although some visitors may not be effective pollinators, pollinator effectiveness i...

A central goal of comparative life-history theory is to derive the general rules governing growth, metabolic allocation, and biomass partitioning. Here, we use allometric theory to predict the relationships among annual leaf, stem, and root growth rates (GL, GS, and GR, respectively) across a broad spectrum of seed plant species. Our model predicts isometric scaling relationships among all thre...

This study was conducted at the Agricultural Research Station, King Abdulaziz University at Hada El-Sham during 2007 and 2008 seasons to improve the seed yield of sesame (Sesamum indicum L.) in the Makkah Region, Saudi Arabia. Split plot design with four replications was used in this study. Main plot treatments were four nitrogen rates (0, 100, 150 and 200 kg N/ha) and the sub plot treatments w...

The conservation of rare plant species hinges on our ability to identify the underlying mechanisms that limit rare plant populations. Theory on rarity suggests that both predispersal seed predation and competition can be important mechanisms influencing abundance and/or distribution of rare plant populations. Yet few studies have tested these interactions, and those that have evaluated each mec...