Configural Frequency Analysis (CFA) Revisited — a New Look at an Old Approach

Configural frequency analysis (CFA) is a widely used method for the identification of types and syndromes in contingency tables. However, the type model of CFA shows some major deficiencies. In this paper, we propose an alternative modeling of types eliminating the shortcomings of CFA. Basically, a type is modeled as a combination of traits or symptoms that deviates from the pattern of association holding true for the complementary configurations of the contingency table. The new approach is formulated in terms of a log-linear model. It is shown that parameter estimation can be performed with methods known from the analysis of incomplete contingency tables. Test procedures for confirmatory analysis and methods for exploratory search for type configurations are developed. We illustrate the methodology with two practical examples.     

Functional morphology of the feeding system in the ruff — Gymnocephalus cernua (L. 1758) — (Teleostei,Percidae)

The ruff, Gymnocephalus cernua, is a European freshwater fish that feeds by sucking up small invertebrates from the bottom of ponds and slow flowing rivers. The feeding movements have been studied by simultaneous electromyography of seventeen muscles of the head and cinematographic techniques. A theoretical model of movements imposes the functional demands of suction upon an abstraction of the form of a teleost head. Three phases in the feeding act, a preparatory phase, a suction phase and a transport phase, could be correlated with the observed movements and EMGs. Differences between the predicted and the actual movement are discussed. Two different types of feeding occur. The direction, magnitude and duration of the suction forces during feeding are modified, according to the position of the prey. A mechanism preventing early mandibular depression allows sudden and strong suction. Retardation of the suspensorial abduction during the overall expansion of the buccal cavity is ascribed to kinetic interrelations with the hyoid arch. Protrusion of the upper jaws also permits an earlier closure of the mouth and directs the food-containing waterflow posteriorly. When the fish is feeding on sinking prey, protrusion occurs later in the sequence of movements than when it is feeding from the bottom. As the protruded jaws produce a downwardly pointed mouth this retardation aims the suction force.     

A Note on the Estimation of the Population Mean in Stratified Random Sampling Using Two Auxiliary Variables

In this paper, a two‐phase sampling estimator for a stratified population mean using two auxiliary variables x and z is considered when the stratum mean of x is unknown but that of z is known. The suggested estimator under its optimal condition is found to be more efficient than the one using only x.     

A possible explanation of emergence patterns of Baetis vernus curtis (Ins.: Ephemeroptera) on the breitenbach — schlitz studies on productivity,Nr. 22—

Baetis vermis, a major contributor to the biomass of the Breitenbach, shows a remarkable degree of fluctuation in its emergence, which — in the years under observation (1969–1975)—ranges from univoltine to trimodal patterns. It is postulated, that warm overwintering temperatures produce unimodal emergence whereas cold winter temperatures (esp. periods with less than 5° C) produce bimodal or trimodal emergence. The relations between egg-hatching, larval growth and temperature are discussed.     

Tooth replacement in the bowfin (Amia calva — Holostei)

The dissected tooth bearing bones of 20 specimens of Amia calva (Pisces:Holostei) ranging from the third to tenth season have been examined radiographically and in alizarin red S stained and cleared specimens. Although forms of alternate (1:1) tooth series replacement (sensu Edmund, '60) were frequently observed, even in the youngest, immature specimens, many examples of irregular replacement were recorded. In several bones, the maxillae in particular, series with every third (2:1) or fourth (3:1) tooth replacing were seen and possible patterns of 2:2, were recorded. It is concluded that these data are not consistent with the Zahnreihen concept but support a morphogenic field concept of tooth development.     

Urine Marking and Territoriality in Galago alleni (Waterhouse, 1837 — Lorisoidea,Primates) — A Field Study by Radio-telemetry

Behavioral interactions among color-marked individual Vidua chalybeata that shared common song dialects were observed for 5 years in two populations at Lochinvar National Park, Zambia. Social interactions involved ♂♂ visiting and competing for mating sites and ♀♀ visiting ♂♂ in an apparent sampling of potential copulating partners. Differences in mating success among the polygynous ♂♂ were compared with male behavior and territory resources, and criteria were developed to test the importance of intrasexual male competition and female mate choice in explaining the mating system of the populations. Song behavior best explained differences in mating success of ♂♂ with lesser effects of neighboring ♂♂ and the defensible resources around the call-sites. The social organization of song populations resembles that of a dispersed lek with ♀♀ visiting many ♂♂ but mating with few ♂♂. We discuss the observations on indigobirds in relation to behavioral selection, sexual selection, and mating systems. Mating systems of certain populations and species are compared using statistics of individual mating success.