The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

Advancements in development and characterization of biodiesel: A review

An ever increasing demand of fuels has been a challenge for today’s scientific workers. The fossil fuel resources are dwindling day by day. Biodiesel seems to be a solution for future. Biodiesel is an environmentally viable fuel. Out of the four ways viz. direct use and blending, micro-emulsions, thermal cracking and transesterification, most commonly used method is transesterification of vegetable oils, fats, waste oils, etc. Latest aspects of development of biodiesel have been discussed in this work. Yield of biodiesel is affected by molar ratio, moisture and water content, reaction temperature, stirring, specific gravity, etc. Biodegradability, kinetics involved in the process of biodiesel production, and its stability have been critically reviewed. Emissions and performance of biodiesel has also been reported. 2008 Elsevier Ltd. All rights reserved.

Review article Advancements in development and characterization of biodiesel: A review

Biodiesel, defined as the mono-alkyl esters of vegetable oils or animal fats, is an environmentally attractive alternative to conventional petroleum diesel fuel (petrodiesel). Produced by transesterification with a monohydric alcohol, usually methanol, biodiesel has many important technical advantages over petrodiesel, such as inherent lubricity, low toxicity, derivation from a renewable and domestic feedstock, superior flash point and biodegradability, negligible sulfur content, and lower exhaust emissions. Important disadvantages of biodiesel include high feedstock cost, inferior storage and oxidative stability, lower volumetric energy content, inferior low-temperature operability, and in some cases, higher NO
 x
 exhaust emissions. This review covers the process by which biodiesel is prepared, the types of catalysts that may be used for the production of biodiesel, the influence of free fatty acids on biodiesel production, the use of different monohydric alcohols in the preparation of biodiesel, the influence of biodiesel composition on fuel properties, the influence of blending biodiesel with other fuels on fuel properties, alternative uses for biodiesel, and value-added uses of glycerol, a co-product of biodiesel production. A particular emphasis is placed on alternative feedstocks for biodiesel production. Lastly, future challenges and outlook for biodiesel are discussed.

https://www.biofuelscoproducts.umn.edu/sites/biodieselfeeds.cfans.umn.edu/files/2009-moser-biodiesel_production.pdf

Biodiesel production, properties, and feedstocks

Birds in Europe: Their conservation status

How much do PCB toxic equivalents account for PHAH toxicity in predatory birds

We use a simple multiplicative spatio-temporal model to describe variability in a sequence of water quality monitoring data from headwater streams in the Conwy catchment, North Wales. The spatial component of the model treats concentrations as due to simple mixing of a small number of distinct source types, each associated with particular upstream catchment characteristics. The temporal component allows concentration variability due to seasonal or hydrological change. We apply the model using three candidate catchment characteristic classifications to generate mixing concentrations, and a seasonal component to describe temporal variability, and test a range of sub-models. We identify a cross-classification of soil and land cover as providing the best spatial indicator of water quality of the classifications considered. The spatial model based on a selected grouped cross-classification was shown to account for between 35% and 90% of the spatial variability and the seasonal model accounted for between 45% and 100% of the temporal variability in the data. Analysis of residuals showed an inverse relationship between DOC and sulphate and between hydrogen ion concentration and calcium and magnesium. We also found residual correlations between sites which are strongly related to landscape class. These are attributed to landscape class by time interactions which are not accounted for in the simple multiplicative model.

/pdf/application-of-a-simple-multiplicative-spatio-temporal-1afpr49x4n.pdf

Application of a simple multiplicative spatio-temporal stream water quality model to the river Conwy, North Wales

Neonicotinoid use on cereals and sugar beet is linked to continued low exposure risk in honeybees

Neonicotinoids are currently licensed for use in 120 countries, making accurate nontarget species sensitivity predictions critical Unfortunately, such predictions are fraught with uncertainty, as sensitivity is extrapolated from only a few test species and neonicotinoid sensitivities can differ greatly between closely related taxa Combining classical toxicology with de novo toxicogenomics could greatly improve sensitivity predictions and identify unexpectedly susceptible species We show that there is a >30-fold differential species sensitivity (DSS) for the neonicotinoid imidacloprid between five earthworm species, a critical nontarget taxon This variation could not be explained by differential toxicokinetics Furthermore, comparing key motif expression in subunit genes of the classical nicotinic acetylcholine receptor (nAChR) target predicts only minor differences in the ligand binding domains (LBDs) In contrast, predicted dissimilarities in LBDs do occur in the highly expressed but nonclassical targets, acetylcholine binding proteins (AChBPs) Critically, the predicted AChBP divergence is capable of explaining DSS We propose that high expression levels of putative nonsynaptic AChBPs with high imidacloprid affinities reduce imidacloprid binding to critical nAChRs involved in vital synaptic neurotransmission This study provides a clear example of how pragmatic interrogation of key motif expression in complex multisubunit receptors can predict observed DSS, thereby informing sensitivity predictions for essential nontarget species

Off-Target Stoichiometric Binding Identified from Toxicogenomics Explains Why Some Species Are More Sensitive than Others to a Widely Used Neonicotinoid.

M. Glória Pereira

Papers

How much do PCB toxic equivalents account for PHAH toxicity in predatory birds

Application of a simple multiplicative spatio-temporal stream water quality model to the river Conwy, North Wales

Neonicotinoid use on cereals and sugar beet is linked to continued low exposure risk in honeybees

Off-Target Stoichiometric Binding Identified from Toxicogenomics Explains Why Some Species Are More Sensitive than Others to a Widely Used Neonicotinoid.

Polymerisation versus degradation of sunflower oil spilled in the marine environments.