Validity of hair mineral testing

The variance of testing was compared between the College of American Pathologists clinical survey and that of a recent review about hair mineral testing. The review suggested that the accuracy of hair mineral testing was unreliable. In general, there was a greater range of variance in the College of American Pathologists testing results. These latter results are based on laboratory testing and are used as a “yardstick” to determine if a laboratory passes or fails that analyte and are considered a “gold standard.” An extract, which resulted from a method that avoided the washing step, was compared among five laboratories. Very good precision resulted, indicating that the varied washing steps used by the laboratories in a recent review were probably the source of much variance. Analysis of hair analysis seemed to yield important information in several historical or forensic cases involving Ludwig von Beethoven, Napoleon Bonaparte, ex-US-presidents Zachary Taylor and Andrew Jackson, and Charles Hall, an Arctic explorer. Several elements that were reviewed, including arsenic, cadmium, cobalt, germanium, lead, lithium, manganese, mercury, nickel, and thallium, showed relationships between body burden, dosage, and exposure or toxicity. Evidence of toxicity could not be found by measuring hair aluminum or vanadium. Chromium, selenium, and zinc seemed to have nutritional value. Ratios of hair elements with clinical importance could not be found.     

Performance evaluation of a new algorithm for the detection of remote homologs with sequence comparison

A detailed analysis of the performance of hybrid, a new sequence alignment algorithm developed by Yu and coworkers that combines Smith Waterman local dynamic programming with a local version of the maximum-likelihood approach, was made to access the applicability of this algorithm to the detection of distant homologs by sequence comparison. We analyzed the statistics of hybrid with a set of nonhomologous protein sequences from the SCOP database and found that the statistics of the scores from hybrid algorithm follows an Extreme Value Distribution with lambda approximately 1, as previously shown by Yu et al. for the case of artificially generated sequences. Local dynamic programming was compared to the hybrid algorithm by using two different test data sets of distant homologs from the PFAM and COGs protein sequence databases. The studies were made with several score functions in current use including OPTIMA, a new score function originally developed to detect remote homologs with the Smith Waterman algorithm. We found OPTIMA to be the best score function for both both dynamic programming and the hybrid algorithms. The ability of dynamic programming to discriminate between homologs and nonhomologs in the two sets of distantly related sequences is slightly better than that of hybrid algorithm. The advantage of producing accurate score statistics with only a few simulations may overcome the small differences in performance and make this new algorithm suitable for detection of homologs in conjunction with a wide range of score functions and gap penalties.     

Modelling spatial dynamics of fish

Our ability to model spatial distributions of fish populations is reviewed by describing the available modelling tools. Ultimate models of the individual's motivation for behavioural decisions are derived from evolutionary ecology. Mechanistic models for how fish sense and may respond to their surroundings are presented for vision, olfaction, hearing, the lateral line and other sensory organs. Models for learning and memory are presented, based both upon evolutionary optimization premises and upon neurological information processing and decision making. Functional tools for modelling behaviour and life histories can be categorized as belonging to an optimization or an adaptation approach. Among optimization tools, optimal foraging theory, life history theory, ideal free distribution, game theory and stochastic dynamic programming are presented. Among adaptation tools, genetic algorithms and the combination with artificial neural networks are described. The review advocates the combination of evolutionary and neurological approaches to modelling spatial dynamics of fish.     

Sustainability Indicators at the Firm Level

After reviewing recent attempts to develop sustainability indicators, this article shows how the principles of productive efficiency can be used to elaborate such indicators at the firm level. The theory of productive efficiency is somewhat expanded to incorporate fundamental issues of sustainable development: environment, equity, and futurtty. Efficiency, in the expanded notion of productive efficiency, is viewed as a necessary condition for sustainability. Working with aggregate performance indicators, it is important not to lose track of the relevant basic information. Therefore, instead of elaborating one unique indicator; we propose to implement several kinds of indicators, each of which stresses one particular focus (e.g., environmental vs. social concems). The definition of sustainable development indicators is illustrated with reference to a small data set of U.S. fossil fuel-fired electric utilities. In a sustainabiltty perspective, two important aspects are stressed, namely, the use of nonmewable resources and the inclusion of employment as a variable to maximize rather than an input to minimize. The article ends with a discussion of the significance of, and limits to, the proposed indicators.     

Lactate Production from Glucose and Response to Insulin in Perifused Adipocytes from Mesenteric and Epididymal Regions of Lean and Obese Rats

Lactate, an important metabolic substrate for peripheral tissues and the liver, is released in significant amounts from adipose tissue. Using a perifusion system, we measured lactate production from glucose and response to insulin in isolated mesenteric and epididymal adipocytes removed from fed or fasted male Wistar rats at two stages of growth and development: (a) lean rats (7 weeks to 9 weeks old, weighing ～250 g), and (b) fatter rats (6 months to 8 months old, weighing ～550 g). The results show that lactate production in perifused adipocytes is regulated by the prior nutritional state of the animals, by the adipose tissue region, and by the presence of insulin in the perifusate. In fat cells from lean rats, basal lactate production was significantly higher (p<0.05) in mesenteric cells when compared with epididymal cells, both in the fed state (7.8 nmol/10⁷ fat cells per minute vs. 2.9 nmol/10⁷ fat cells per minute) and after 2 days of fasting (13.6 nmol vs. 3.5 nmol). When the response to 1 mU/mL insulin was studied, however, the relative increase in lactate production produced by insulin was greater in the epididymal cells than in the mesenteric cells, in both the fed (194% vs. 91% over basal, respectively) and fasted (360% vs. 55% over basal, p<0.05) state. When larger epididymal adipocytes from fatter rats were compared with an equal number of smaller epididymal cells from leaner rats, the larger cells produced 4.99 nmol of lactate/10⁷ fat cells per minute, whereas the smaller cells produced 2.93 nmol (p=0.08). Large fat cells showed a small and nonsignificant response to insulin in either type of cell (epididymal vs. mesenteric) or nutritional state (fed vs. fasted). This study indicates that distinct regional differences exist in lactate production and response to insulin. Mesenteric adipose tissue, which drains directly into the portal vein and provides substrates to the liver, may be an important source of lactate for the hepatic processes of gluconeogenesis and glycogenesis.     

The influence of predation risk on diet selectivity: A theoretical analysis

Studies that have examined the effect of experimental increases in predation risk on diet selectivity have shown both decreased and increased diet selectivity. A possible explanation for these disparate results emerges from an examination of the prey sets used in these studies, which differed in the relationship between the values of risk components associated with the capture of different prey types (‘danger’) and their profitabilities. When less profitable prey were more dangerous, selectivity increased with predation risk. When prey were equally dangerous, selectivity did not change. Finally, when the more profitable prey were also more dangerous, selectivity decreased with risk. Here, we examine theoretically the influence of a forager's estimate of the probability that a predator is present (φ) on the selection of diets from prey sets with varying danger–profitability relationships. A dynamic programming model is used to determine the maximum attack time (or distance) for each of two types of prey, differing in their energetic content, for a range of forager energy state and φ levels. The diets which would result if foragers attacked prey according to the rules provided by the dynamic model are then determined. The model results indicate that the prey danger–profitability relationship determines the diet selectivity response to φ, confirming that variation in this relationship could be responsible for the range of experimental results. This revised version was published online in July 2006 with corrections to the Cover Date.     

The regulation of brood reduction in Booted Eagles Hieraaetus pennatus through habitat heterogeneity

Brood reduction, the death of one or more chicks through siblicide or starvation, can occur through density‐dependence in fecundity. Brood reduction may arise in territorial breeding systems either as a response to a high level of territorial interference in a situation of high density or as a result of habitat heterogeneity. To test the predictions of the two main hypotheses that attempt to explain how density‐dependent fecundity is generated, the Habitat Heterogeneity Hypothesis (HHH) and the Individual Adjustment Hypothesis (IAH), we analysed the relationship between density and fecundity in an expanding population of Booted Eagles in Doñana National Park, Spain, using an 18‐year data series. We also studied the occurrence and frequency of brood reduction in the same Booted Eagle population to appreciate further its effects and the factors that influence its occurrence and frequency. Our results support the HHH in the present situation of high density, as fecundity in the better territories (older and more frequently occupied) was higher than in low quality territories and was not affected by population density in high density periods. Nevertheless, the fecundity of high quality territories was affected (although not significantly) by population density in periods of low density, suggesting that the IAH was supported when only high quality territories were occupied. Older territories were used more frequently and chicks in these areas hatched earlier and suffered lower mortality than in new territories. We found a significant negative relationship between mean fecundity and its skewness, a finding that also supports HHH. During years of food shortage, less frequently occupied territories suffered higher rates of brood reduction. Brood reduction in this Booted Eagle population was a consequence of the heterogeneous structure of the habitat, with some territories having a higher probability of brood reduction than others. Parental nutritional condition did not affect brood reduction. The effect of brood reduction on nestling quality and population dynamics is also discussed.     

Mycoheterotrophy evolved from mixotrophic ancestors: evidence in Cymbidium (Orchidaceae)

Background and Aims

Nutritional changes associated with the evolution of achlorophyllous, mycoheterotrophic plants have not previously been inferred with robust phylogenetic hypotheses. Variations in heterotrophy in accordance with the evolution of leaflessness were examined using a chlorophyllous–achlorophyllous species pair in Cymbidium (Orchidaceae), within a well studied phylogenetic background.

Methods

To estimate the level of mycoheterotrophy in chlorophyllous and achlorophyllous Cymbidium, natural ¹³C and ¹⁵N contents (a proxy for the level of heterotrophy) were measured in four Cymbidium species and co-existing autotrophic and mycoheterotrophic plants and ectomycorrhizal fungi from two Japanese sites.

Key Results

δ¹³C and δ¹⁵N values of the achlorophyllous C. macrorhizon and C. aberrans indicated that they are full mycoheterotrophs. δ¹³C and δ¹⁵N values of the chlorophyllous C. lancifolium and C. goeringii were intermediate between those of reference autotrophic and mycoheterotrophic plants; thus, they probably gain 30–50 % of their carbon resources from fungi. These data suggest that some chlorophyllous Cymbidium exhibit partial mycoheterotrophy (= mixotrophy).

Conclusions

It is demonstrated for the first time that mycoheterotrophy evolved after the establishment of mixotrophy rather than through direct shifts from autotrophy to mycoheterotrophy. This may be one of the principal patterns in the evolution of mycoheterotrophy. The results also suggest that the establishment of symbiosis with ectomycorrhizal fungi in the lineage leading to mixotrophic Cymbidium served as pre-adaptation to the evolution of the mycoheterotrophic species. Similar processes of nutritional innovations probably occurred in several independent orchid groups, allowing niche expansion and radiation in Orchidaceae, probably the largest plant family.     

An Approach to Integrating Environmental Considerations Within Managerial Decision‐Making

Recent environmental trends, including (1) an expansion of existing command and control directives, (2) the introduction of market‐based policy instruments, and (3) the adoption of extended producer responsibility, have created a need for new tools to help managerial decision‐making. To address this need, we develop a nonlinear mathematical programming model from a profit‐maximizing firm's perspective, which can be tailored as a decision‐support tool for firms facing environmental goals and constraints. We typify our approach using the specific context of diesel engine manufacturing and remanufacturing. Our model constructs are based on detailed interviews with top managers from two leading competitors in the medium and heavy‐duty diesel engine industry. The approach allows the incorporation of traditional operations‐planning considerations—in particular, capacity, production, and inventory—together with environmental considerations that range from product design through production to product end of life. A current hurdle to implementing such a model is the availability of input data. We therefore highlight the need not only to involve all departments within businesses but also for industrial ecologists and business managers to work together to implement meaningful decision models that are based on accurate and timely data and can have positive economic and environmental impact.     

Macronutrient balancing in free‐ranging populations of moose

At northern latitudes, large spatial and temporal variation in the nutritional composition of available foods poses challenges to wild herbivores trying to satisfy their nutrient requirements. Studies conducted in mostly captive settings have shown that animals from a variety of taxonomic groups deal with this challenge by adjusting the amounts and proportions of available food combinations to achieve a target nutrient balance. In this study, we used proportions‐based nutritional geometry to analyze the nutritional composition of rumen samples collected in winter from 481 moose (Alces alces) in southern Sweden and examine whether free‐ranging moose show comparable patterns of nutrient balancing. Our main hypothesis was that wild moose actively regulate their rumen nutrient composition to offset ecologically imposed variation in the nutritional composition of available foods. To test this, we assessed the macronutritional composition (protein, carbohydrates, and lipids) of rumen contents and commonly eaten foods, including supplementary feed, across populations with contrasting winter diets, spanning an area of approximately 10,000 km². Our results suggest that moose balanced the macronutrient composition of their rumen, with the rumen contents having consistently similar proportional relationship between protein and nonstructural carbohydrates, despite differences in available (and eaten) foods. Furthermore, we found that rumen macronutrient balance was tightly related to ingested levels of dietary fiber (cellulose and hemicellulose), such that the greater the fiber content, the less protein was present in the rumen compared with nonstructural carbohydrates. Our results also suggest that moose benefit from access to a greater variety of trees, shrubs, herbs, and grasses, which provides them with a larger nutritional space to maneuver within. Our findings provide novel theoretical insights into a model species for ungulate nutritional ecology, while also generating data of direct relevance to wildlife and forest management, such as silvicultural or supplementary feeding practices.