Resting Energy Expenditure: Systematic Organization and Critique of Prediction Methods

There are many published methods for predicting resting energy expenditure (REE) from measured body composition. Although these published reports extend back almost a century, new related studies appear on a regular basis. It remains unclear what the similarities and differences are among these various methods and what, if any, advantages the newly introduced REE prediction models offer. These issues led us to develop an organizational system for REE prediction methods with the goal of clarifying prevailing ambiguities in the field. Our classification scheme is founded on body composition level (whole‐body, tissue‐organ, cellular, and molecular) and related components as the REE predictor variables. Each existing REE prediction method by body composition must belong to one body composition level. The suggested classification system, founded on a conceptual basis, highlights similarities and differences among the diverse REE‐body composition prediction methods, provides a framework for teaching REE‐body composition relationships, and identifies important future research opportunities.     

Annual, daily and intradiurnal variation of Celtis pollen in the city of La Plata, Argentina

The behaviour of Celtis airborne pollenwas studied for a period of three years(1998–2000) in the city of La Plata. The pollengrains were captured with a Lanzoni trap andthe maximum pollination period was observed tooccur during the end of winter and spring inthe three years. The annual values of pollenconcentration varied, and a significantdecrease was observed during 2000. The greatestairborne pollen record was in October with anaverage of 82.3% in relation to its totalconcentration during 1998–2000. Based on theintradiurnal behaviour analysis, it wasobserved that the maximum pollination peakoccurs at 2H when the temperaturereaches its maximum values. Considering thethree sampling years, the meteorologicalvariables that most influenced the processes of pollen emission,dispersion and transportation in the atmospherewere: maximum and minimum temperature andrainfall.     

Avian richness and abundance in temperate Danish forests: tree variables important to birds and their conservation

Many studies on avian diversity and forest structure have focused onfiner scale forest variables such as foliage height diversity, foliagediversity, foliage density, vertical distribution of vegetation and horizontalvegetation density. From a conservation and forestry operational point of viewit would be of great interest if tree variables influenced directly by forestrymanagement decisions also had significant influence on avian richness andabundance. The species, age and size of a tree are examples of such treevariables. A great number of studies also have focused on avian diversityindices to reveal relationships with vegetation variables. However, it may bemore appropriate for foresters and conservation officers to operate withrichness and abundance measures directly, because indices complicateinterpretations on the relative importance of the two variables (richness andabundance) constituting the index. Fourteen managed temperate forests in Denmarkwere investigated for avian species richness and abundance and related tomeasures on different tree variables influenced directly by forestry managementdecisions. A rapid assessment method of avian richness and abundance wasemployed. It consisted of point-counts of bird richness and abundance within 1km² of forest. General linear models were tested byanalyses of variance statistics to reveal the tree variables most important toavian richness and abundance. It was found that more old trees, more treespecies and more tree size-classes correlated with more bird species andindividuals. However, some variation in bird richness and abundance was alsorelated to site quality and/or chance colonization. Moreover, it was shown thatthe guild of cavity-nesting birds correlated positively to age of tree stand.The potential number of bird species in Danish forest is similar to that innearly pristine forest in Poland, and much larger than that recorded in any ofthe forests investigated. Together with the results above, this indicates a highpotential for squeezing in more avian species in a higher quality forest from abiodiversity point of view. Modern Danish forestry affects tree variablesinfluenced directly by forestry management decisions. Such tree variables havegreat influence on avian richness and abundance, but simple measures in forestrypractices can be taken to enhance the conservation of bird richness andabundance.     

Airborne pollen data of Platanaceae in Santiago de Compostela (Iberian Peninsula)

The pollen count of the Platanus genus in the atmosphere of Santiago de Compostela (Galicia, Spain) was carried out from 1993 to 1998, with the pollen of this taxon representing 6% of total identified pollen. The principal pollination period (P.P.P.) was centred on the months of March and April, with an average duration of 23 days.During the study period we obtained negative correlations with precipitation and humidity and positive ones with temperature and hours of sunshine, with a confidence index of more than 90%. On the basis of the six-year study period, we also calculated the average accumulated temperature required to trigger the onset of flowering, which oscillated between 330 and 456 °C, with this result being confirmed for 1999 (437 °C). We also observed that the values of maximum pollen concentration of this taxon in the last 7 years (1993–1999), were obtained on days during the P.P.P. with maximum temperatures above 18 °C. The model of intradiurnal variation reflects, for the majority of years, a greater representation during the central hours of the day.     

On Model-Choice in Discrimination with Categorical Variables

An algorithm for model selection in discrimination with categorical variables is presented. It is based on four models applied hierarchically and linked with a build-up procedure of feature-selection. The choice of models and features is ensured by a consequent cross-validation. Results of an application in medical diagnostics are described.     

Randomized Blocks Analysis for the Exponential Distribution

A procedure for analyzing randomized blocks experiments for uncensored exponential random variables is presented. Its small sample behavior is studied in several simulations. Sample size requirements are given.     

Spectral resolution of cardio-circulatory variations in men measured by autorhythmometry over 2 years

An analogue of the periodogram method for unequally spaced data is presented with a view to resolving the frequency structure of the observations. The algorithm is explicitly based on the sequential least squares procedure. In particular, the key concept is that the with-in-plot spectral analysis can be augmented by the between-plot information to make inferences about common characteristics. It is also shown how the between-plot random variations can be incorporated into the multiple harmonic regression model. A detailed spectral analysis investigates the periodic fluctuations in four cardio-circulatory variables, measured by autorhythmometric observation by eight men at rest and extending over a time span of 2 years. The spectral curves show the existence of circadian and circaseptan rhythmicities. The amplitude modulation of the dian rhythm by circaseptan variation is assimilated with the rhythmicity of work during the week. The blood-pressure variables situate their maximum annual peak in the winter period. These quasi-periodic fluctuations appear to be related to the amount of physical activity performed in time by the subjects.