Individual variability of behavioural responses by Wandering Albatrosses (Diomedea exulans) to human disturbance

Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.

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Formation of Oil/Water Emulsions due to Electrochemical Instability at the Liquid/Liquid Interface

This study is dedicated to the development of manufacturing principles of food emulsions for food functionalization and formulation. In the experiments presented, the emulsions are generated using the effects of electrochemical instability and surface tension decrease at a polarized liquid/liquid interface. Polarization of the oil/liquid interface is studied in various aqueous systems including electrolytes and water-based solutions of cationic, anionic, zwitterionic, and nonionic surfactants. The physical features of the obtained emulsions, such as hydrodynamic flow patterns, droplet size distribution, and emulsion organization, are described. The efficacy of different electrode configurations is also evaluated. The theoretical model of the liquid/liquid interface polarization and experimental data obtained from various emulsification regimes are presented.

Behavioural and physiological mechanisms of polarized light sensitivity in birds

Polarized light (PL) sensitivity is relatively well studied in a large number of invertebrates and some fish species, but in most other vertebrate classes, including birds, the behavioural and physiological mechanism of PL sensitivity remains one of the big mysteries in sensory biology. Many organisms use the skylight polarization pattern as part of a sun compass for orientation, navigation and in spatial orientation tasks. In birds, the available evidence for an involvement of the skylight polarization pattern in sun-compass orientation is very weak. Instead, cue-conflict and cue-calibration experiments have shown that the skylight polarization pattern near the horizon at sunrise and sunset provides birds with a seasonally and latitudinally independent compass calibration reference. Despite convincing evidence that birds use PL cues for orientation, direct experimental evidence for PL sensitivity is still lacking. Avian double cones have been proposed as putative PL receptors, but detailed anatomical and physiological evidence will be needed to conclusively describe the avian PL receptor. Intriguing parallels between the functional and physiological properties of PL reception and light-dependent magnetoreception could point to a common receptor system.     

Leitlinien zur molekulargenetischen Diagnostik: Fragiles-X und Fragiles-X assoziiertes Tremor/Ataxie Syndrom

Ohne Zusammenfassung

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Manipulations of polarized skylight calibrate magnetic orientation in a migratory bird

1. Young migratory birds enter the world with two representations of the migratory direction, one coded with respect to the magnetic field, the other with respect to celestial rotation. The preferred magnetic direction of migratory orientation is malleable early in life: it may be calibrated by celestial rotation, observed either in daytime or at night.
2. Previous experiments showed that early experience with skylight polarization was necessary for calilbration to occur in daytime. In this study, we performed a direct manipulation of patterns of polarized skylight at dawn and dusk.
3. Hand-raised Savannah sparrows (Passerculus sandwichensis) were allowed to observe the clear sky for 1 h prior to local sunrise and for one h following local sunset. They never saw the Sun nor stars. The birds observed the sky through bands of polarizing material (HNP'B) aligned with the e-vector axis in one of three orientations with respect of the azimuth of sunrise and sunset: group 1) 90°; group 2) 45° CW; group 3) 45° CCW.
4. Tested indoors in covered cages in both shifted and unshifted magnetic fields, the autumn migratory orientation of the three groups differed significantly. Group 1 oriented magnetic N-S, group 2 oriented magnetic NW-SE, and group 3 oriented magnetic NNE-SSW. These observed orientation directions are very close to those predicted by the manipulations of polarized skylight.
5. These results indicated that a fairly simplified, static polarized light pattern viewed a limited number of times only in dawn and dusk snapshots is sufficient to produce calibration of the preferred magnetic migratory orientation direction.

     

Threatened species and the spatial concentration of humans

Public policies that encourage high-density human living arrangements have been predicated explicitly on the assumption that certain spatial distributions of a fixed-size human population are less environmentally damaging than others. We examine the empirical validity of this assumption across 127 countries by analyzing whether the concentration of human presence in each country is related statistically to the percentage of species that were on the IUCN Red List in 2004. Our findings indicate that concentration of the human population is associated with reduced imperilment among amphibians but increased imperilment among reptiles, and birds.

Responses of marine organisms to physical and chemical impacts

Studies on the effects of a variety of exogenous and anthropogenic environmental factors, including endocrine disruptors, heavy metals, UV light, high temperature, and others, on marine organisms have been presented at the 2nd Bilateral Seminar Italy–Japan held in November 2006. Reports were discussed in order to reveal the current situation of marine ecosystems, aiming at evaluation and prediction of environmental risks.

Sunset,skylight polarization and the migratory orientation of yellow-rumped warblers,Dendroica coronata

Celestial light cues visible at sunset appear to play an important role in the nocturnal orientation of several species of night-migrating birds. The pattern of skylight polarization, an especially prominent geographical reference at sunrise and sunset, influences the orientation behaviour of migratory birds. Yellow-rumped warblers were capable of seasonally appropriate cage orientation at dusk and were sensitive to manipulation of the axis of skylight polarization (E-vector). A series of experimental treatments was designed to examine the relationship between sunset position and skylight polarization. The window panels of hexagonal enclosures were fitted with a depolarizer and a polaroid filter to rotate the E-vector, and mirrors to reflect the position of sunset. The results indicate that this migrant minimizes sunset position as an orientation relative to skylight polarization and may depend upon the latter to orient at dusk. The possibility that yellow-rumped warblers calibrate their sun compass in relation to polarized light remains a question for future research.     

Hennigian Phylogenetic Systematics and the ‘Groundplan’ vs. ‘Post-Groundplan’ Approaches: A Reply to Kukalová-Peck

The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.

Is it a revolution?

Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence properties is also discussed.

Gridcast—a next generation broadcast infrastructure?

Gridcast is an R&D project investigating grid ideas and technologies in the broadcasting technical infrastructure. In this paper I discuss the business and technical issues in building infrastructures to support broadcasters and outline the structure of the Gridcast grid-based service oriented architecture for broadcasting playout support.

Evidence of gonochorism in a grouper, <Emphasis Type="Italic">Mycteroperca rosacea</Emphasis>, from the Gulf of California,Mexico

The sexual pattern and sexual development of the leopard grouper, Mycteroperca rosacea, were investigated from 483 specimens collected from the Gulf of California, Mexico. Histological and population data indicated a gonochoric sexual pattern. Some juveniles passed through an immature bisexual phase of gonadal development, but no evidence of post-maturational sex change was found. The immature bisexual phase is believed to be associated only with male development. The size distribution and size at sexual maturity were similar for both males and females. In accordance with predictions of the size-advantage model, the gonochoric sexual pattern of M. rosacea is likely influenced by its group-spawning mating system.

Hierarchical analysis of piecewise affine models of gene regulatory networks

A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions. In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.

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Superposition of masking releases

We are constantly exposed to a mixture of sounds of which only few are important to consider. In order to improve detectability and to segregate important sounds from less important sounds, the auditory system uses different aspects of natural sound sources. Among these are (a) its specific location and (b) synchronous envelope fluctuations in different frequency regions. Such a comodulation of different frequency bands facilitates the detection of tones in noise, a phenomenon known as comodulation masking release (CMR). Physiological as well as psychoacoustical studies usually investigate only one of these strategies to segregate sounds. Here we present psychoacoustical data on CMR for various virtual locations of the signal by varying its interaural phase difference (IPD). The results indicate that the masking release in conditions with binaural (interaural phase differences) and across-frequency (synchronous envelope fluctuations, i.e. comodulation) cues present is equal to the sum of the masking releases for each of the cues separately. Data and model predictions with a simplified model of the auditory system indicate an independent and serial processing of binaural cues and monaural across-frequency cues, maximizing the benefits from the envelope comparison across frequency and the comparison of fine structure across ears.

The connectionist framework for gene regulation

I show that gene regulation networks are qualitatively consistent and therefore sufficiently similar to linearly seperable connectionist networks to warrant that the connectionist framework be applied to gene regulation. On this view, natural selection designs gene regulation networks to overcome the difficulty of development. I offer some general lessons about their evolvability that can be learned by examining the generic features of connectionist networks.

Causal Explanation of Indonesian Forest Fires: Concepts, Applications, and Research Priorities

Problems with studies, claims, and assumptions that have been made about the causes of fires in Indonesia's tropical moist forests are identified, and the kinds of concepts, methods, prioritizing, and data needed to resolve the problems are discussed. Separate sections are devoted to studying ignitions, studying fire susceptibility and fire behavior, and using the goal of causal explanation to guide interdisciplinary research.