Iron limitation of primary productivity prevails across much of the Southern Ocean but there are exceptions; in particular, the phytoplankton blooms associated with the Kerguelen Plateau, Crozet Islands, and South Georgia. These blooms occur annually, fertilized by iron and nutrient-rich shelf waters that are transported downstream from the islands. Here we use a high-resolution (1/128) ocean g...

The antifertility effects of Abrus precatorius root bark meal (APRB) on Coptodon zillii juvenile was determined by a 42 days feeding experiment, with the inclusion levels 0g, 6g, 12g, 18g and 24g/kg diet. Water volume 20 litres in plastic tank (50cm x 27cm 35 cm dimension) maintained throughout period experiment. fed at 4% body weight. In male fish, testis weight, milt volume, count motility du...

Ecologists have long treated temperate forests as systems limited by nitrogen (N) availability. Widespread concern about the effects of anthropogenic N on forested ecosystems has inspired experimental simulation of the effects of chronic N addition. This study investigates the effects of 8 years (1996–2003) of simulated chronic N deposition on tree growth and mortality in an upland mixed-oak fo...

INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 Gametogenesis and fertilization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 358 Inheritance of scutellum color. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

Soil organic carbon (SOC) and nitrogen (N) are directly influenced by tillage, residue return and N fertilization management practices. Soil samples for SOC and N analyses, obtained from a 23-year field experiment, provided an assessment of nearequilibrium SOC and N conditions. Crops included corn (Zea mays L.) and soybean [Glycine max L. (Merrill)]. Treatments of conventional and conservation ...

BACKGROUND In vitro fertilization (IVF) of eggs by frozen and thawed C57BL/6J mouse sperm is inhibited by dead sperm and enhanced by preincubation of the sperm in calcium-free medium. In other species, the presence of sperm killed by freezing and thawing has been associated with the generation of hydrogen peroxide. METHODOLOGY/PRINCIPAL FINDINGS The proportion of eggs fertilized by cryopreser...

With the introduction of intracytoplasmic sperm injection (ICSI), couples with severe male factor infertility have achieved fertilization and clinical pregnancy rates comparable to other in-vitro fertilization (IVF) patients. However, failure of fertilization still occurs in some patients despite the utilization of microsurgical sperm injection techniques. How such fertilization failure after I...

Fertilization of the sea urchin egg is accompanied by the assembly of an extracellular glycoprotein coat, the fertilization membrane. Assembly of the fertilization membrane involves exocytosis of egg cortical granules, divalent cation-mediated association of exudate proteins with the egg glycocalyx (the vitelline layer), and cross-linking of the assembled structure by ovoperoxidase, a fertiliza...

In many species, females are thought to benefit from polyandry due to the reduced risks of fertilization by genetically incompatible sperm. However, few studies that have reported such benefits have directly attributed variation in female reproductive success to the interacting effects of males and females at fertilization. In this paper, we determine whether male x female interactions influenc...

Genetic variation within populations depends on population size, spatial structuring, and environmental variation, but is also influenced by mating system. Mangroves are some of the most productive and threatened ecosystems on earth and harbor a large proportion of species with mixed-mating (self-fertilization and outcrossing). Understanding population structuring in mixed-mating species is cri...