Calculations of the number of curves on a Calabi-Yau manifold via an instanton expansion do not always agree with what one would expect naively. It is explained how to account for continuous families of instantons via deformation theory and excess intersection theory. The essential role played by degenerate instantons is also explained.

Cell proliferation is coupled with nutrient availability. If nutrients become limited, proliferation ceases, because growth factor and/or PI3-kinase activity levels become attenuated. Here, we report an exception to this generality within a subpopulation of Drosophila neural stem cells (neuroblasts). We find that most neuroblasts enter and exit cell cycle in a nutrient-dependent manner that is ...

The effect of various concentrations of sulphates in the nutrient solutions (I – 200, II – 400, and III – 600 mg SO4 2dm) on sulphur content in plants as well as plant height and leaf area of tomato plants grown with nutrient film technique (NFT) were investigated. Total-S and S-SO4 levels were determined in the leaf blades of the upper, medium and lower plant parts, during 3 phases of tomato g...

two experiments were conducted to evaluate the different levels of selenium supplements on performance, blood metabolites and nutrient digestibility in mehraban male lambs. the first experiment consisted of 18 lambs, 4-5 months of age and 35.9±2.7 kg average in weight randomly allotted to 3 treatments. treatments were: 1) control diet (a diet without selenium, containing 0.06 ppm of selenium), ...

Cushion plants are important components of alpine and Arctic plant communities around the world. They fulfill important roles as facilitators, nurse plants and foundation species across trophic levels for vascular plants, arthropods and soil microorganisms, the importance of these functions increasing with the relative severity of the environment. Here we report results from one of the few expe...

The response of soil biogeochemical properties to external nutrient loading may serve as sensitive indicators of eutrophication in wetland ecosystems. We investigated the effects of nutrient loading on the distribution of soil C, N and P in four wetlands of the Florida Everglades: Water Conservation Area (WCA)-1, WCA-2a, WCA-3a and Taylor Slough. The nutrient-impacted zones extended from water-...

water and nutrient availability are two major constraints to forage maize production in arid and semi-arid areas; however, the effect of different n levels from organic and inorganic sources on nutrient (i.e., n and p) efficiency under drought stress conditions is not well known for maize faming. thus, a field study was conducted with the objective of determining the effect of n fertilization a...

Type 2 diabetes (T2D) burden is increasing globally. However, evidence regarding nutrient patterns associated with the biomarkers of T2D is limited. This study set out to determine the nutrient patterns associated with fasting glucose and glycated haemoglobin the biomarkers of T2D. Factor analysis was used to derive nutrient patterns of 2010 participants stratified by urban/rural status and gen...

background and objectives: the quefts model is using for optimizing fertilizer managements in crops, but it has not been used in iran yet. quefts accounts for interactions among npk affecting the ie of n, p and k and allows differentiation according to different yield levels targeted. it is necessary to determine crops parameters before application the model in the studying area. the first step...